LabCON-V Operating Manual

Transcription

1 LabCON-V Operating Manual T-EIOM.8035 Rev. 008

2 Revisions Date June 1995 August 20th, 1997 March 9th, 1998 May 10th, 2001 Description Original Issue Revised to include the Proto Calibration function and changes in software revision Revised to include 1997 ASTM Standards changes and changes in software revision 4.0. Revised to clarify configuration of LOA.INI file. March 28, 2003 Revised to include changes for versions 4.04 and June 18, 2003 May 26, 2006 April 3, 2007 Revised to include instructions for history file archival. Revised to include details of the CR calibration per ASTM. Revise to add TSF lean steps in section 12.7 and clarify the troubleshooting section. Manual approved by: CSD Any amendment to this manual shall be recorded on this AMENDMENT LOG PAGE. Superseded pages shall be removed, destroyed, and replaced by the amended pages including the updated AMENDMENT LOG PAGE. AMENDMENT NUMBER DATE DESCRIPTION ALL INFORMATION CONTAINED IN THIS MANUAL AND ANY ASSOCIATED DRAWINGS OR ILLUSTRATIONS ARE CONSIDERED PROPRIETARY. THIS MATERIAL MAY NOT BE REPRODUCED WITHOUT THE WRITTEN CONSENT OF CORE LAB REFINERY SYSTEMS. T-EIOM.8035 Rev. 008

3 Table of Contents LabCON-V Operating Manual 1.0 INTRODUCTION... i 1.1 Definitions... i 2.0 OPERATION General DESCRIPTION OF EQUIPMENT Computer Control Chassis Compression Ratio (CR) Converter Knock Intensity FUEL SYSTEM Carburetor Fuel Cooling Sample Shelf Fuel Pumps THEORY OF OPERATION General LabCON Menu Structure GETTING STARTED Introduction System Setup Set Time/Date KI Calibration Compression Ratio (CR) Calibration System Data Barometer Calibration UTILITY MENU FUNCTIONS Utilities Menu Microvalve Initialization Set Barometer I/O Control Fuel Flow Control Microvalve Search Engine Analysis Sample History Display CR Table Monitor Engine T-EIOM.8035 Rev. 008

4 Table of Contents LabCON-V Operating Manual 8.0 CR METHOD OCTANE RATING Preliminary Setup Summary Fuel Identification Rating a Toluene Standard Fuel Toluene Standard Fuel Data Entry TSF Advanced Setup Toluene Standard Fuel Report Temperature Tuning Sample Rating Data Entry Fuel Pump Sequences Sample Rating Report CR Advanced Setup CR METHOD OCTANE RATING DETAILS General Preliminary Adjustments Fuel/Air Search Procedure Final Adjustments Octane Number Tolerance BRACKETING METHOD OCTANE RATING General Bracketing Method Data Entry Bracketing Method Advanced Setup Temperature Tuning Final Report BRACKETING METHOD OCTANE RATING DETAILS General Preliminary Adjustments Fuel/Air Search Procedure Final Adjustments Fuel Sequencing PROTOTYPE CALIBRATION Description Preparation Data Entry Prototype Calibration Details Final Report Calibration History T-EIOM.8035 Rev. 008

5 Table of Contents LabCON-V Operating Manual 12.7 Options File TROUBLE SHOOTING LABCON-V LABCON ALARMS Description Low Priority Alarms High Priority Alarms Appendix A - ASTM Tables and Parameters Appendix B - Archiving History Files T-EIOM.8035 Rev. 008

6 1.0 INTRODUCTION 1.1 Definitions The terms used in this manual are the same as those found in the "ASTM Manual for rating fuels by the Research and Motor Methods". 1 Cylinder Height - the relative position of the engine cylinder with respect to the piston which is indicated by a micrometer, dial indicator, or digital counter. Detonation meter - the electronic amplifier/signal conditioning equipment that accepts the electrical signal from the detonation pickup and provides an electrical signal for display on a knock meter or strip chart recorder. Digital Counter Reading - a numerical indication of cylinder height, indexed to a basic setting at a prescribed compression pressure when the engine is motored. Guide Tables - the specific relationship between cylinder height (compression height) and octane number at standard knock intensity for specific primary reference fuel blends tested at standard barometric pressure. Knock Intensity - a measure of the level of combustion-related knock produced when fuel is evaluated in the knock testing unit. Maximum knock intensity fuel/air ratio - that proportion of fuel to air which produces the highest knock intensity for each fuel in the knock testing unit, provided this occurs within specified carburetor sight glass level limits. Octane Number - the measure of the resistance of a fuel to knock, which is assigned to a test fuel based upon the operation in the knock testing unit at the same standard knock intensity as that of a specific primary reference fuel blend. 1 ASTM Annual Book of Standards, Vol T-EIOM.8035 i Rev. 008

7 Primary reference fuels - ASTM iso-octane, ASTM n-heptane, volumetrically proportioned mixtures of ASTM iso-octane and ASTM n-heptane, or blends of ASTM dilute tetraethyllead in ASTM iso-octane which define the octane number scale. Spread - the sensitivity of the detonation meter expressed in knock meter divisions per octane number. Standard knock intensity - that level of knock produced when a primary reference fuel blend of specific octane number is used in the knock testing unit at maximum knock intensity fuel/air ratio, with the cylinder height (compression ratio) set to the prescribed guide table value, and the detonation meter adjusted to produce a knock meter reading of 50. Toluene standardization fuel - those volumetrically proportioned blends of two or more of the following: reference fuel grade toluene, ASTM n-heptane, dilute tetraethyl lead, and ASTM iso-octane that have empirically determined octane numbers and prescribed rating tolerances. These blends are sensitive to engine operating conditions and dictate whether a knock testing unit is in acceptable condition as a prerequisite to fuel testing at any specific octane level. T-EIOM.8035 ii Rev. 008

8 2.0 OPERATION 2.1 General LabCON-V is a laboratory octane analyzer developed by Core Lab Refinery Systems to determine the Research or Motor Method octane number of motor fuels. Using a computer and a special fuel handling system, it is designed to provide automatic octane analysis on single or multiple samples using Knock Intensity (KI) and Compression Ratio (CR) signals. Operation is via simple menu driven instructions. Results are displayed on a computer display and stored in a history file for later retrieval. Knock intensity (KI) is a measure of the level of combustion related knock produced when a fuel is evaluated in a knock testing unit. This knock intensity signal generated by each fuel is measured and stored. The signal from the CR converter is a measure of the cylinder height in relation to the piston. This measure is related to compression ratio as described in the method and also stored in the computer. In operation, a primary reference fuel is run to determine standard knock intensity as described in ASTM Methods D2699, D2700 and IP Methods 237 and 236. Subsequent samples are then run, first resolving the fuel/air setting for maximum knock, and then adjusting the compression ratio to arrive at the knock intensity set point determined on the primary reference fuel. For the compression ratio method, this compression ratio setting, automatically compensated for barometric pressure, is then compared against the cylinder height versus octane number guide tables to determine the final octane. For the bracketing method, the knock intensity of the sample is bracketed at a constant compression ratio between the knock intensity of the two reference fuels. The octane number is then calculated by method of interpolation. Knock Intensity is graphically displayed along with other information throughout the test. At the completion of the final sample in a group, results of all samples are displayed on the display, stored in a file for later access, and sent to a printer. LabCON, by way of its sophisticated software, "learns" as it makes adjustments Core Lab Refinery Systems 1 T-EIOM.8035 Rev 008

9 during the ratings. All of this is transparent to the engine operator and provides a more efficient and precise octane result. A hard disk, large enough to retain approximately 1000 ratings, is used to store results. LabCON-V has the ability to print rating reports to virtually any attached printer. Core Lab Refinery Systems 2 T-EIOM.8035 Rev 008

10 3.0 DESCRIPTION OF EQUIPMENT The industrial computer specifications are included in the Appendix of this document. Due to varying availability of computer equipment, not all LabCON's use identical computer systems. 3.1 Computer Control Chassis The control chassis is mounted in the CFR engine console. Mounted on the chassis is a 24vdc power supply, a relay board, and 4 solid state relays. The 24vdc power supply provides the power to run the fuel pumps and microvalve stepper motor. The relay board is used to provide the following functions; fuel pump selection, CR motor brake control, microvalve direction control, auto/manual CR interrupt control (power to the manual CR switch is interrupted when under computer control). The 4 solid state relays provide CR raise and lower control, CR auto/manual control, and microvalve stepper motor pulse control. Core Lab Refinery Systems 3 T-EIOM.8035 Rev 008

11 3.2 Compression Ratio (CR) Converter Compression ratio position is measured as the output of a voltage across a CR position converter. Calibration of the converter correlates the output voltage to the engine's cylinder height. This signal is then filtered and converted to digital counter units. The older LabCON-V model's use a linear potentiometer for the CR converter, whereas the newer models use a load variable differential transformer (LVDT) for converting the compression ratio. The potentiometer has been replaced with the LVDT device to provide greater accuracy and reliability. 3.3 Knock Intensity The knock intensity signal is an input from the detonation meter. This signal is conditioned and calibrated to agree with the Weston knock meter. Since the meter is not linear there are 6 calibration points required. 4.0 FUEL SYSTEM The overall fuel system consists of three sub-assemblies: the carburetor, sample pumps and rotometer valves, and a heat exchanger. This section describes each assembly in further detail. Core Lab Refinery Systems 4 T-EIOM.8035 Rev 008

12 4.1 Carburetor LabCON samples are handled through a special fuel system attached to the right side of the standard carburetor. Bowls #1 and #2 on the left side of the standard carburetor have been retained for additional use. A major difference between the two sides of the carburetor is the means by which the fuel to air ratio (fuel/air) can be determined for maximum knock intensity. With the original equipment carburetor, fuel/air is changed by varying the liquid head height against a fixed orifice metering jet. The liquid head is varied by raising or lowering the float chamber by turning a knurled knob below the respective bowl. The fuel level is observed in the sight glass to the right of the float chambers. The #1 or #2 position of the fuel selector valve is used when operating the standard system. LabCON uses the spill tower and microvalve side of the carburetor. The fuel selector valve must be in #4 position for LabCON operation. The spill method maintains a fixed liquid head in the center column. This liquid head is equal to a 1.3 setting on the standard fuel sight glass, well within the limits of 0.7 to 1.7. Fuel to air ratio is changed by means of a variable metering jet, also called the microvalve. Maximum knock is determined very accurately utilizing a microvalve in.0005" steps. The fuel/air search routine utilizes a stepper motor under computer control to move the microvalve through a series of "rich" and "lean" steps to arrive at a fuel/air setting for maximum knock. The fixed liquid head requirement for the spill type carburetor is met by supplying more fuel than the engine consumes. The excess fuel overflows the center spill section into the spill trough and then through the spill drain. The #4 position on the selector valve is used for the spill system. Sample fuel is supplied to the microvalve by individual fuel pumps. These pumps take the fuel from a sample container, where it passes through a heat exchanger and then to the pump. From the pump, fuel flow to the carburetor is regulated by a flow rotometer control valve. The four fuel nozzles are mounted in an aluminum dome with a glass cap. The fuel nozzles are located over the spill trough and depend on fuel velocity to reach the center Core Lab Refinery Systems 5 T-EIOM.8035 Rev 008

13 position of the carburetor. This design eliminates the possibility of fuel contamination from the nozzles dripping when not in use. 4.2 Fuel Cooling A heat exchanger, located within the sample handling system is for use with a self contained water chilling unit. The heat exchanger cools the sample which is necessary to minimize problems associated with high vapor pressure fuels and because of the effect of temperature on fuel density. 4.3 Sample Shelf A sample shelf furnished with LabCON is bolted to the crankcase. This shelf while providing a place to set samples, also provides mounting for the fuel flow rotometers, housing for the fuel pumps, and the heat exchanger and electrical connections. 4.4 Fuel Pumps Fuel pumps are mounted to the underside of the sample shelf. They are used to transfer fuel from the sample container to the carburetor. Each pump has an probe which is placed into the sample container during an analysis. Core Lab Refinery Systems 6 T-EIOM.8035 Rev 008

14 5.0 THEORY OF OPERATION 5.1 General LabCON has been programmed to emulate ASTM Methods D-2699, D2700 and IP Methods 237 and 236, for Rating Motor Fuels by Research and Motor Methods using the ASTM-CFR engine. It utilizes memory resident tables and parameters as outlined in both Research and Motor methods. By means of a special fuel handling and carburetor system, LabCON-V can automatically sequence through up to 4 samples that are pumped directly from the sample container to the carburetor. The carburetor is a spill type carburetor using a computer controlled microvalve and jet to regulate fuel flow to the engine. By identifying Primary Reference fuels by their octane, adjustments are made to realize standard knock intensity and arrive at a mid-scale knock intensity set point. Samples rated by the compression ratio method are then run by adjusting the sample to standard knock intensity using the set point determined by the PRF, and reading the octane corrected to 29.92" (101.3kPa) from a table. Samples rated by the bracketing method are also adjusted to standard knock intensity and then bracketed between two reference fuels at a constant compression ratio. The octane number is then calculated by mathematical interpolation. Toluene Standardization Fuels (TSF or TBlends) are identified as to their calibrated value, run by LabCON, and the final results are then checked for acceptance. If the final results exceed the allowable limits, a message is sent to the display making the operator aware of the condition. The operator can continue testing or take corrective action. During any portion of a fuel/air search or a rating, knock intensity versus time is graphically depicted on the screen with the ability to re-scale for increased resolution. Many checks are made in the course of a test to ensure an efficient rating without a loss in precision. These include an initial knock intensity stability check on each fuel to determine whether the engine is stable enough to rate that fuel. Additional stability checks Core Lab Refinery Systems 7 T-EIOM.8035 Rev 008

15 are made to ascertain stability prior to controlling the compression motor or prior to a octane number calculation. Spread (knock vs. octane), is examined to determine sensitivity and calculate compression movements so as to avoid over and under-shooting of KI set points. A sophisticated fuel/air search algorithm is performed to determine a very precise fuel/air ratio. Upon conclusion of the test, additional checks are performed to determine if the final octane number is within acceptable tolerances. A full complement of alarm parameters is constantly monitored to provide a safe operation along with dependable results. Among these are high, low, or unstable knock intensity, and microvalve movement that attempted to move past the physical limits (see section LabCON V Software Alarms). Barometric compensation to 29.92" (101.3kPa) for compression ratio versus octane tables is automatic on entry of the barometric pressure or if obtained from pressure transducer (later models). Context sensitive help screens are available for assistance on all displays and data fields. When the operator is not using the LabCON, selecting the Screen Saver option from the main menu (F4) will turn the screen blank until a key is pressed. This allows for uninterrupted testing during longer test runs. Core Lab Refinery Systems 8 T-EIOM.8035 Rev 008

16 5.2 LabCON Menu Structure The tree structure below illustrates the layout of the LabCON processes. The menus are divided into three groups, Octane Analysis, Utilities Menu and System Menu. These 3 groups are accessible from the main menu. Each of these groups is then broken down to permit accessing their specific functions. Main Menu Octane Analysis Menu (F1) Utilities Menu (F2) System Menu (F3) CR Sample Ratings (F1) I/O Control (F1) KI Calibration (F1) CR Toluene Rating (F2) History (F2) CR Calibration (F2) Bracketing (F3) MV Initialize (F3) System Setup (F3) Proto Calibration (F4) MV Search (F4) Set Time/Date (F4) Display CR Table (F5) System Data (F5) Monitor Engine (F6) Barometer Calibration (F6) Set Barometer (F7) Engine Analysis (F8) Core Lab Refinery Systems 9 T-EIOM.8035 Rev 008

17 6.0 GETTING STARTED - After Installation LabCON-V Operating Manual 6.1 Introduction On power up, LabCON will automatically display the Main Menu. From here you can access the octane analysis menu, utilities menu, or the system menu. NOTE: The function key F9 is used to exit all displays except the Help display which uses the function key F10. After installation, some preliminary calibration and testing must be performed before running an octane analysis. The tests will generate data and adjustment factors which LabCON will use when rating samples. They include the following: System Setup Define permanent parameters. Set Time/Date Define the current time and date. KI Calibration Calibrate the knock meter to LabCON. CR Calibration Calibrate the compression ratio to LabCON. Barometer Calibration Enter the site barometer reading. Core Lab Refinery Systems 10 T-EIOM.8035 Rev 008

18 MV initialization Initialize the microvalve position. Engine Analysis Perform a stability check on the engine. From the Main Menu, items 1 through 5 above are accessible from the System Menu. Items 6 and 7 are accessible form the Utilities Menu. The above commands are menu driven with help screens to further explain the procedure and the frequency required. 6.2 System Setup This procedure will define the test method, research or motor, the elevation, ASTM toluene tables to use, and the customer name and location. It is only invoked when the test method, elevation, or customer name is to be changed. If the engine type is changed, all calculated system information is lost and the KI and CR must be calibrated followed by an Engine Analysis. On the system setup screen press F1 to setup for a research motor or F2 to setup for motor method. After selecting RON or MON, the customer name field will appear. Enter the customer name with an external keyboard or obtain alpha characters by pressing the up and down arrow keys. Use the right and left arrow keys to move right and left. If MON is selected as the engine type, LabCON-V will prompt you to select the elevation in which the engine will be operating by pressing the F1, F2 or F3 keys. You will then be prompted for the ASTM tables to use. F1 chooses the 1986 ASTM tables and F2 chooses the current ASTM table as defined by the 1997 ASTM manual. Upon completion you will be returned to the setup menu. Core Lab Refinery Systems 11 T-EIOM.8035 Rev 008

19 6.3 Set Time/Date Use this function to set the LabCON V time and date. Time is represented using a 24 hour clock. For example, 1:00 pm is shown as 13:00. Use the up and down arrow keys or the Enter key to change fields. Select the field and enter the correct value in the field to be changed. To exit, press enter or the down arrow while the cursor is on the minutes field. 6.4 KI Calibration This procedure accessed via the F1 function key on the system menu will calibrate the system knock intensity display to the CFR engine knock meter. If the engine is equipped with a 501-C meter, the zero adjusting screw can be used to vary the voltage for the calibration. If it is not a C meter then an external millivolt source (P/N 7800, supplied with LabCON V ) should be used. If an external source is used, disconnect the cable from the rear of detonation meter terminal labeled METER, and connect to the millivolt source. Use the knob on the millivolt source to vary the voltage source. To calibrate, adjust the calibration voltage to the different voltage levels as prompted. Press Enter after adjusting to each level. On completion, LabCON s knock intensity will agree with the knock meter. If the 501-C zero screw was used to vary the voltage, it should be reset for zero output. This procedure should be repeated whenever the knock meter is changed. Core Lab Refinery Systems 12 T-EIOM.8035 Rev 008

20 6.5 Compression Ratio (CR) Calibration CR calibration is an important function of LabCON. It indexes and scales the output voltage of the compression ratio converter to the cylinder height. The engine must be running and thoroughly warm before starting. This function should be repeated whenever the CR converter s mounting hardware is disturbed. Before starting this procedure, it is necessary to set the barometer to the uncompensated value because compensation per ASTM tables will be in reference to inches Hg. To set the barometer to 29.92, first disable the transducer using the calibration option from the System menu. Then manually enter the value using the Set Barometer option from the Utilities menu. To ensure the reading on the engine mechanical digital counter is the uncompensated value, adjust the compression until the upper and lower counters read the same value. To run this procedure, select the CR Calibration option from the System menu and follow the prompts. You will be asked to set the engine's mechanical digital counter to the uncompensated value (research 755, motor 595) displayed on the screen and press enter. Follow the prompts to set the CR at the higher value (1179 for Research and 1019 for Motor), pressing enter, and then return to the first value. The compression ratio is now calibrated and should match the digital counter to +/- 1 unit. You will now be prompted to enter the high and low CR limits. These are limits that LabCON V will observe whenever controlling the CR and should provide a safe operating range. If while performing CR control, LabCON tries to exceed these limits, the test will be aborted and the message, "CR Limit - Exceeded Limits Entered in by Operator", will be displayed. It will be necessary to reset these limits whenever this occurs or it is known the octane lies outside the limits. Suggested limits are: Engine Type Lower Limit Upper Limit Research Engine 400 (49.6 Octane) 1000 (102.6 Octane) Motor Engine 300 (58.0 Octane) 900 (97.5 Octane) Core Lab Refinery Systems 13 T-EIOM.8035 Rev 008

21 After performing the calibration, set the barometer reading to match the site value using either the manual entry or calibrated entry which will use the built-in transducer, if available. The CR digital counter units should now match the ASTM correction tables. 6.6 System Data The system data display contains factors used by LabCON-V during rating cycles. Some of the data is updated every rating to increase the efficiency of the rating. The KI STABILITY FACTOR is an average slope of the knock intensity trace versus time. The stability factor is determined during the engine analysis procedure and is used during all CR ratings to determine when to perform compression motor control. During the rating, when the knock intensity is considered to be un-stable CR control is delayed until the engine stabilizes. This value is only updated during an engine analysis procedure and typical stability factors can be anywhere from.035 to.110. The CR DRIVE FACTOR is used by LabCON to determine the duration of the CR motor control to obtain a desired digital counter setting. For most CR motors, a value of approximately is usually normal. This means that for every 100 milliseconds of motor control the cylinder head moves approximately 1 digital counter unit. This value is updated only during the engine analysis procedure. The CALCULATED SPREAD value is the number of knock meter units equal to one octane Core Lab Refinery Systems 14 T-EIOM.8035 Rev 008

22 number. This value is updated every time a spread check is performed; either during an engine analysis procedure or during an octane rating. If the spread check option is turned off, then default values of 10 for Motor method and 15 for Research method engines are used and displayed. The CR TRANSDUCER ERROR is determined during the engine analysis procedure and is a measure of the error introduced to the CR converter due to the vibration of the engine during the combustion stroke. When the engine is firing, the combustion cycle causes the cylinder head to rise slightly, which causes the CR converter signal to be erratic. This errata is filtered out of the signal to achieve a very accurate cylinder height measurement. The percentage of data filtered from the acquired data is called the CR transducer error. Normal transducer errors are usually in the range of 5-35%. If the error exceeds this typical range, some adjustments may be required. The adjustment may be as simple as tightening the clamping sleeve tension or may require a more drastic step like verifying the clamping sleeve shims are to specifications. The CR/KI RESPONSE FACTOR is calculated during the engine analysis procedure and is a measure of knock intensity response to the compression motor control. For example, if the CR raise response factor is 5.9 sec/ki, this would indicate that when the CR motor was driven up (to increase the CR) for one second than the knock would increase approximately 6 units. This value is used during a CR rating when trying to control the CR motor to obtain a knock value equivalent to that of the PRF set point. The CR LIMITS are the alarm limits as entered in during the system setup exercise. The PRF MV AVERAGE and SAMPLE MV AVERAGE values are running averages of the fuel/air ratio setting for both a PRF and the unknown samples. These values are used as an approximate starting fuel/air position during sample ratings. These values significantly decrease overall rating time by allowing the engine to run very close to the optimum fuel/air ratio before it is actually determined. These values are updated during every CR or Bracketing sample rating. The TOLUENE TABLE YEAR and ASTM CR TABLE values simply describe the compression ratio guide table currently in use by LabCON-V. Core Lab Refinery Systems 15 T-EIOM.8035 Rev 008

23 6.7 Barometer Calibration The later model LabCON-V is equipped with an internal automatic barometric pressure transducer. The reading generated by this transducer can be used directly or calibrated to match the local on-site barometer reading. Calibrating to match the local reading is recommended. Calibration of the barometer is available by selecting F6 on the System Menu. During the calibration, LabCON V will provide an un-calibrated barometer reading and prompt for the local reading. If the internal reading is acceptable, press Enter. If it is desired to have the internal reading agree with the local barometer, then enter the local reading. Upon entering the local reading, LabCON will compare and store any difference in the configuration file. It will then use this difference to make the internal reading match the local reading. If the transducer should fail and the signal is not sensed, LabCON will produce an error message and the barometric pressure will have to be manually entered in from the Utilities Menu. The automatic pressure transducer can be disabled by pressing F1 during the calibration. Once the transducer is disabled, manual is entry is required. After calibration the LabCON CR reading will equal the uncompensated digital counter reading plus any offset, as determined from the ASTM tables for research or motor method, required for the current barometric pressure. Core Lab Refinery Systems 16 T-EIOM.8035 Rev 008

24 7.0 UTILITY MENU FUNCTIONS 7.1 Utilities Menu During routine startup, the utilities menu is normally the first selection from the main menu. The utility menu provides functions used daily following a routine engine startup. It also contains selections to help analyze engine instability problems. The MV Initialization should be the first selection from this menu (if LabCON was powered off) and can be done with the engine down or running. After initializing the microvalve position then the next step would be to set the current barometric pressure. If an automatic barometric sensor is installed then there is no need to set the barometer. 7.2 Microvalve Initialization MV initialization is accomplished by reading the microvalve position from the barrel of the micrometer and entering the value. This step is necessary because LabCON does not read the position. LabCON remembers the number of steps it has taken and calculates its position using the MV initialization entry. Therefore this must be entered every time LabCON is powered up or whenever the microvalve is turned manually. After entering the current microvalve position, pressing enter will store the position. Pressing F1 after entering the position will reset the microvalve running averages. They should only be reset if the microvalve was initialized improperly and the accumulated averages are incorrect. Pressing F7 or F8 will store the entered microvalve position in the PRF average or sample average respectively. This allows for quick adaptation to high octane or component fuel's microvalve settings and afterwards returning to the normal setting. Core Lab Refinery Systems 17 T-EIOM.8035 Rev 008

25 7.3 Set Barometer Barometric pressure can be entered by pressing F7 on the Utilities Menu or during the start of a sample rating. This value will be used to automatically compensate the compression ratio to 29.92" Hg. Enter the barometer reading at the cursor and press Enter. Note: Later models with the barometric pressure transducer can also enter the pressure at this prompt if a faulty transducer is suspected. First, you will need to disable the transducer from the barometer calibration display. 7.4 I/O Control The I/O Control display is usually used during engine warm-up and is provided as diagnostic tool for troubleshooting the electronics. From this display, you can adjust the compression and microvalve settings, select a fuel pump, and set the fuel flow. The function keys, F1 through F7, are used as toggle switches. Pressing them once will start or enable a function. Pressing them a second time will stop or disable a function. The function keys perform the following functions: Core Lab Refinery Systems 18 T-EIOM.8035 Rev 008

26 F1 - F4: Turns pumps 1-4 on or off respectively. Can be used to flush pumps or select a pump for warm-up. LabCON won t allow exiting this display with more than one pump running. CAUTION - Avoid running pumps without fuel for extended periods of time. This will cause premature pump failure. F5: Enables the operator to manually raise or lower the CR using the up and down arrows. F6: Enables the operator to manually move the fuel microvalve rich or lean by using the up and down arrow keys. The up arrow moves the microvalve rich, and the down arrow moves the microvalve lean. F7: Enables the operator to manually operate the CR lockout feature. This feature is used by LabCON to ensure that the operator does not use the manual CR switch at the same time as LabCON thereby causing damage to the CR motor. Note: The computer cabinet temperature will be displayed below the CR units. If equipped with a barometric transducer, the transducer voltage will be displayed below CR voltage. 7.5 Fuel Flow Control Fuel flow is very important in all phases of octane testing. Sufficient fuel must be supplied to the center of the carburetor to provide continuous overflow, but not so great as to distort the meniscus. This will generally be in the area of 30 to 40 ml per minute. The flow is controlled by the valve in the flow meter (see figure). This should be set during warm-up, Core Lab Refinery Systems 19 T-EIOM.8035 Rev 008

27 under knocking conditions, and rechecked before performing a fuel/air search. When setting the valve it is better to first open the valve more than needed, and then slowly close it until you reach the correct fuel flow. Experience has shown that it is better to set the flow at a higher level (40ml) then needed to avoid starving the engine for fuel. If the engine doesn t get enough fuel, the fuel/air will be inaccurate and may cause the test terminate prematurely or report inaccurate results. 7.6 Microvalve Search This function accessed via function key F4 will perform a fuel/air search for maximum knock using the current fuel pump. This function should only be performed on a thoroughly warm engine. A knock intensity versus time graph will be displayed on the screen during the search. The status bar at the bottom of the display will update every 5 seconds. Displayed from left to right are the microvalve setting, knock intensity, CR setting, fuel pump number, and the search status. Status is displayed as: CR Control, SearchB (broad), SearchN (narrow) and FINAL. LabCON will move to a series of microvalve settings to establish the area of peak knock intensity and then calculate the final result. At the completion of the fuel/air search the status will change to FINAL. 7.7 Engine Analysis An engine analysis is only required after the system setup has been invoked. Information obtained during this test is utilized by LabCON for a more efficient rating without any loss in precision. For example, it calculates a CR/KI response factor to minimize over and under driving of the CR motor and a KI stability factor which is used to determine when an engine has reached equilibrium. Since this procedure only takes 5 or 6 minutes, it is recommended that this test be run each shift. This information, along with other information, can be seen on the system data screen. See section LabCON System Core Lab Refinery Systems 20 T-EIOM.8035 Rev 008

28 Data for further information. To run an engine analysis, a fuel pump must be selected and the engine must be warmed up and running at standard knock intensity. Pressing F8 from the Utilities Menu invokes the engine analysis procedure. As mentioned earlier, the procedure takes approximately five to six minutes. During the analysis, the knock intensity versus time is graphically depicted on the display. Upon completion, the KI SPREAD, the KI STABILITY FACTOR, and the CR TRANSDUCER ERROR results are displayed. The values can be viewed at any time after exiting the Research Engine Detonation Meter Spread Motor Engine Detonation Meter Spread KnockUnits peroctane Research Octane Number Knock Units per Octane Motor Octane Number results report by going to the system data display. The KI spread value varies depending on the engine type and the octane range of the fuel. Refer to the illustrations above for typical knock meter spreads usually obtained during the engine analysis. The KI stability factor is a measure of the engine s stability while running a fuel at standard knock intensity. Typical values for the stability factor are from to LabCON will use the stability Core Lab Refinery Systems 21 T-EIOM.8035 Rev 008

29 factor to determine when the engine has reached equilibrium after make control adjustments or before calculating an octane number. The CR transducer error is a measure of the error introduced to the CR converter due to the vibration of the engine during the combustion stroke. When the engine is firing, the combustion cycle causes the cylinder head to rise slightly which causes the CR converter signal to be erratic. This errata is filtered out of the signal to achieve a very accurate cylinder height measurement. The percentage of data filtered from the acquired data is called the CR transducer error. Normal transducer errors are usually in the range of 5-35%. If the error exceeds this typical range, some adjustments may be required or an electronic component may have failed. The adjustment may be as simple as tightening the clamping sleeve tension or may require a more drastic step like verifying the clamping sleeve shims are to specifications. To verify that the electronics is working properly, go to the I/O Test display and verify that the CR voltage is steady when at a fixed compression ratio position and the engine is not running. 7.8 Sample History The history option on the Utilities menu will list all samples in the current working directory. There are three directories of files maintained; CR method samples, bracketing method samples, and proto calibration reports. Press the function key F7 to switch between the directories of the files. There is a maximum of 1000 files allowed in each directory. If the limit is approaching LabCON will not allow any more samples to be run until some files are deleted from the history directory by using the delete key F5. Each file can be retrieved for operator review and printing by using the directional arrows to highlight the selection and press Enter. If you Core Lab Refinery Systems 22 T-EIOM.8035 Rev 008

30 don t know the sample identifier of a particular sample you can search for it if you know a few letters by selecting the search key F1. All PRF are stored with a P prefixed to the identifier entered as well as a T for Toluene and an S for sample. All data files all have a 1", 2", or a 3" appended to the identifier which designates the history file as the reading number taken on the fuel. 7.9 Display CR Table This option, accessible from F5 on the Utilities menu, displays the compression ratio guide table currently in use. This table is useful when setting the engine in the range of the sample you are about to rate. The table is displayed in the familiar row and column format as show in the ASTM Book of Standards Monitor Engine This selection accessed by pressing F6 on the utilities menu is used to graphically observe the knock intensity over time for stability and drifting. The utility is helpful when diagnosing engine ignition, carburetor, and valve problems. You can press function keys F4, F5, or F6 to re-scale for better resolution. The data acquired from the monitor engine function can be saved to a file for later recall under the monitor identifier. The time limit for the monitor engine utility is 16 minutes. The monitor data file is overwritten at the end of each monitor engine function. Core Lab Refinery Systems 23 T-EIOM.8035 Rev 008

31 8.0 CR METHOD OCTANE RATING 8.1 Preliminary Setup Summary Octane is determined on a thoroughly warmed engine operating at standard knock intensity. A routine sequence of events for a daily startup of LabCON could proceed in the following manner. A full complement of help screens with examples is available for each screen and data entry field as needed. 1. Power up LabCON and start the engine. 2. Check to see that fuel cooler is running. The carburetor jacket should be cold. Normally, the fuel cooling unit should not be shut down. 3. From the Utilities menu, select F3 - MV Initialization and enter the microvalve position followed by pressing Enter. 4. Select F1 - I/O control and select a fuel pump for warm-up fuel. Using the control keys F5 and F6 with the arrow keys, adjust the compression ratio and microvalve for suitable knock. 5. At completion of the warm-up period (20-45 minutes), exit the I/O control display and go to the main menu. Press F1 for the octane analysis menu followed by F1 for CR Method octane analysis and F2 for a CR Method toluene rating. See section Rating a Toluene Standard Fuel for details on entering data and starting a TSF rating. 8.2 Fuel Identification LabCON requires that all fuels be identified. Fuels consist of primary reference fuels (PRF), toluene standardization fuels (TSF), and unknown samples for testing. Identification can only be entered as a numeric value if an external keyboard is not available. The identifier s can be up to 8 characters in length, however the input fields are limited to 6 Core Lab Refinery Systems 24 T-EIOM.8035 Rev 008

32 characters. The limit of 6 characters is so LabCON can add additional symbolic characters to the identifiers that are entered. LabCON adds the letter P, T, or S to the beginning of the identifier to denote the history file as a PRF, TSF, or sample respectively. In addition, LabCON appends the character 1", 2", or 3" to identifier to indicate the history file s reading number. CR method fuels have a maximum of 2 readings, whereas the bracketing method fuels have a maximum of 3 readings possible. 8.3 Rating a Toluene Standard Fuel A toluene rating should be performed a least once during each 12 hour period of rating to verify that the engine is able to provide accurate results. In addition, a TSF rating should be performed if the engine has been shut down for more than two hours or has not been operating at standard knock intensity for a long period of time. The CR method toluene rating is invoked from the Main Menu by selecting F1- Octane Analysis followed by F2 - CR Toluene Rating. At this time, the data entry display Toluene Standardization Rating is displayed as depicted below. Refer to section Toluene Standard Fuel Data Entry for further details on the data entry process. Core Lab Refinery Systems 25 T-EIOM.8035 Rev 008

33 8.4 Toluene Standard Fuel Data Entry Data entry is performed by navigating from field to field by pressing the Enter key or the Arrow keys. To display a help window for a particular field, move the cursor to the field and press the F10 function key. The help window will describe the parameter and provide you with the entry range for the data field. In addition, examples will be present where applicable. Consult the TSF Data Entry table for further details on the data entry fields. Toluene Standardization Rating Data Entry TSF Field Barometric Pressure Intake Air Temp (RON) Mixture Temp.(MON) Toluene Identifier Field Description Enter the present barometer reading or if a pressure transducer is installed the current PSI will be displayed. This value will be used to offset the CR guide table to 29.92" Hg. Press F1 to retrieve the correct intake air temperature for the barometric pressure entered previously. Press Enter to accept the recommended temperature or F1 to enter another temperature. Press F1 to view the allowed mixture temperature range. The ASTM recommended range is 285 to 325 degrees Fahrenheit. LabCON will accept a temperature from 250 to 350 degrees Fahrenheit. Type in the identifier of the toluene standard fuel. Most alphanumeric characters are allowed. Up to 6 characters can be entered to identify the TSF. The data can be accessed later using this identifier. The default identifier for a TSF is PRF Identifier Type in the identifier of the primary reference fuel. Up to 6 characters can be entered to identify the TSF. The default identifier for a PRF is When accepting the defaults you will overwrite any previously saved TSF and PRF. PRF Oct. PRF Pump No. TSF Octane Number Enter the octane number of the primary reference fuel. If the reference octane differs from the TSF octane by more than the allowed tolerance an error message will be displayed before the rating is started. Enter the pump number of the primary reference fuel. LabCON will run the primary reference fuel first during the rating. Be sure the flush old fuel from the system before starting the rating. Enter the TSF octane number manually or press F1 to retrieve the octane number from the TSF table. If you use the table, select the octane number using the up and down arrow keys and the Enter key. Core Lab Refinery Systems 26 T-EIOM.8035 Rev 008

34 TSF Field TSF Pump No. Default Pump Halt for KI setpoint Adjust? Global Pump Flush? Use previous PRF Fuel/Air? Field Description Enter the pump number of the toluene standard fuel. LabCON will run the toluene standard after running the reference fuel. Be sure the flush old fuel from the system before starting the rating. Enter a pump to be turned on at the completion of the rating. If entered, the pump will be turned on when the rating is finished. Any pump number from 1 to 4 can be used as the default pump. If this field is left with a dash then the TSF pump will remain on at the completion of the rating. When using a default pump LabCON will automatically adjust the compression to avoid excessive knocking at the rating completion. Use the F1 key to toggle the field to Yes or No. If set to Yes, then LabCON will stop after rating the PRF for operator set point adjustment using the detonation meter. If set to No, then LabCON will only stop if the final PRF knock intensity is outside the 30 to 70 range. Use the F1 key to toggle Yes or No. If set to yes, all pumps selected in the batch will be run for 20 seconds at the start of the first fuel in the sequence. Use the F1 key to toggle Yes or No. If set to Yes, then any previously run PRF fuel/air s will be used as the fuel/air set point. A previous fuel/air set point must be within octane numbers and run within the last 24 hours to be eligible for reuse. Note: All previous PRF fuel/air values are erased when LabCON is powered off. Upon completion of the data entry process selecting function key F8 will instruct LabCON to perform the rating. Before LabCON starts the rating process, it will examine all the entered data for completeness and accuracy. If any of the data is suspect, LabCON will display an error message explaining the condition. For example, entering in a value of 10.0 for the barometric pressure would cause LabCON to issue an Invalid Barometric Pressure message. To acknowledge the message press the F9 key and at this time you must enter in a valid barometric pressure value and press F8 again. Occasionally after pressing the F8 run key LabCON will generate a warning report which displays low priority messages. These messages can be ignored by pressing the F1 Ignore key or the data can be changed by pressing the F2 Change key. At any time before starting the rating you can press the function key F7 to recall all the entered data from the previous rating. This tool is Core Lab Refinery Systems 27 T-EIOM.8035 Rev 008

35 helpful to eliminate repetitive data entry when the entered data is similar from rating to rating. In addition, the F6 key displays the Advanced Setup display which allows changing some less frequently used parameters. See the section titled TSF Advanced Setup for further details. Pressing the function key F10 during the data entry process will display a context sensitive help window to assist you. 8.5 TSF Advanced Setup In addition to the standard data entry display, the advanced setup option also contains data parameters which may be changed. The advanced setup display is accessed by selecting function key F6 at any time during the data entry process. The advanced setup display contains parameters which may need not be changed from rating to rating. The parameters available are; FUEL FLUSH TIME, PERFORM SPREAD CHECK, SEARCH NARROW ONLY, and REPEAT READING. The advanced setup parameters are set to defaults during the system setup process and are saved permanently to the engine configuration file when changed by the LabCON operator. Advanced Setup Defaults Advanced Setup Parameter Default Fuel Flush Time 0 Perform Spread Check Search Narrow Only Repeat Reading NO YES NO The fuel flush time when increased from 0 seconds adds time to the fuel flush period when the fuel pump is first turned on. Some fuels may cause the engine to respond much slower, Core Lab Refinery Systems 28 T-EIOM.8035 Rev 008

36 such as ones that contain TEL. If this is the case, you can increase the total fuel flush time by setting the desired time in this field. The time entered in this field is added to the default fuel flush time already used by LabCON. The standard fuel flush times during a CR method rating are 30 seconds for a PRF or unknown sample, and 50 seconds for a toluene standard fuel. The number of seconds entered into the fuel flush period field is added to all of the fuels standard flush time. The perform spread check option is available to reduce overall rating time during a sample sequence. When this option is set to YES, a spread check is performed on each PRF run in a batch of fuels. The spread is determined by increasing the compression ratio for 2 seconds (approximately 20 DC units) and dividing the knock intensity difference by the octane difference of the two CR positions. This value is then later used by LabCON (CR method rating only) to reduce the error caused by the sample KI set point not exactly equaling the PRF KI set point. Since this error is very small, and in most cases will amount to hundredths of an octane number, LabCON is able to use default spread values in lieu of exact spread values. When setting this option to NO, LabCON uses a spread value of 10 KI units for the motor method engine and 15 KI units for the research method engine. Using these default values can reduce the overall rating time by up to 4 minutes. The search narrow only parameter when set to YES will instruct LabCON to only perform a fuel/air ratio search procedure using the fine or narrow increments. This value in most cases should be set to YES to reduce overall rating times. If LabCON has no history of a valid fuel/air starting point to use, then both the broad and narrow fuel/air increments will be used during the fuel/air ratio search procedure. The repeat reading parameter when set to YES, instructs LabCON to repeat each fuel in the sequence. If there are two fuels in the sequence, then LabCON will take 4 readings, 2 for each fuel. Upon completion of the rating, LabCON will display the octane number for each set of readings and also display the average of the two results. In 1997, the ASTM Book of Standards has indicated that this is the preferred method for running a CR method octane rating. However, the method does also mention that it is permissible to avoid repeating the rating under certain circumstances. Consult the ASTM Book of Standards for further Core Lab Refinery Systems 29 T-EIOM.8035 Rev 008

37 information. 8.6 Toluene Standard Fuel Report After completion of the TSF rating, the final report will be displayed. Accompanied with the report on the lower half of the display will be the rating status message. This message will inform you if the toluene standardization rating has passed or failed. The figure shown depicts a rating report with a passing status message. Other status messages displayed may instruct you to temperature tune to come closer to the calibrated blend value or may inform you that your engine may require maintenance and that temperature tuning is not allowed. If you are instructed to temperature tune than you must increase the mixture or intake air temperature to lower the octane number or lower the temperature to increase the octane number. To print the rating report to an attached printer press the F1 function key. See the next section titled Temperature Tuning for further information. Core Lab Refinery Systems 30 T-EIOM.8035 Rev 008

38 8.7 Temperature Tuning - (Toluene Repeat Option) To take advantage of the TSF temperature tuning option, you must remain on the toluene sample results screen. Temperature tuning is accomplished by adjusting the appropriate temperature on the engine as necessary (intake air temperature on RON or mixture temperature on MON) and repeating the rating by pressing the repeat function key F8. At this time a window will appear with the prompt Enter the new temperature: The toluene repeat function will not perform a fuel/air search and will remain on each fuel approximately 3.5 minutes. Upon completion of the toluene repeat, the new calculated octane will be displayed. If you still do not receive a passing status message then you can continue raising or lowering the engine temperature until the correct octane is achieved. When adjusting the engine temperature be sure to allow enough time for the engine temperature to stabilize after each adjustment. Remember when adjusting the temperature that increasing the temperature decreases the octane number and the exact opposite occurs when decreasing the temperature. For the research engine, vary the temperature approximately 10 Fahrenheit to achieve a rating change of 0.1 to 0.2 octane numbers. For the motor engine, vary the temperature approximately 2 Fahrenheit to achieve a rating change of 0.1 octane numbers. 8.8 Sample Rating Data Entry The CR sample rating data entry display is shown by selecting the function key F1 followed by F1 again from the Main Menu. This display is used for all CR method ratings excluding the TSF blends. Data entry is performed by navigating from field to field by pressing the Enter key or the Arrow keys. To display a help window for a particular field, move the cursor to the field and press the F10 function key. The help window will describe the parameter and provide you with the entry range for the data field. In addition, examples will be present where applicable. Consult the Sample Setup Data Entry table for further details on the data entry fields. Core Lab Refinery Systems 31 T-EIOM.8035 Rev 008

39 Sample Setup Data Entry Table LabCON-V Operating Manual Sample Data Field Barometric Pressure Intake Air Temp (RON) Mixture Temperature PRF KI Setpoint Action/Description Enter the present barometer reading or if a pressure transducer is installed the current PSI will be displayed. This value will be used to offset the CR guide table to 29.92" of Hg. Press F1 to retrieve the correct intake air temperature for the barometric pressure entered previously. Press Enter to accept the recommended temperature or F1 to enter another temperature. Press F1 to view the allowed mixture temperature range. The ASTM recommended range is 285 to 325 degrees Fahrenheit. LabCON will accept a range from 250 to 350 degrees Fahrenheit. * Optional Parameter If you have previously run a reference fuel and obtained a knock set point you may enter that set point in this field. This will prevent LabCON from running the reference fuel again. LabCON will use the entered set point to rate the sample. IMPORTANT NOTE: Leave the fields PRF KI Set point and PRF Octane Number blank if LabCON will be running the reference fuel and determining the reference set point. PRF Octane Number Halt for SP Adjustment? Default Pump Global Pump Flush? *Optional Parameter Enter the octane number of a previously run reference fuel (see PRF KI Set point). IMPORTANT NOTE: Leave the fields PRF KI Set point and PRF Octane Number blank if LabCON will be running the reference fuel and determining the reference set point. Use the F1 key to toggle the field to Yes or No. If set to Yes, then LabCON will stop after rating the PRF for operator set point adjustment using the detonation meter. If set to No, then LabCON will only stop if the final PRF knock intensity is outside the 30 to 70 range. IMPORTANT NOTE: When this option is set to YES, be sure to be present when LabCON prompts you during the rating so the engine won t run out of fuel. Enter a pump to be turned on at the completion of the rating. If entered, the pump will be turned on when the rating is finished. Any pump number from 1 to 4 can be used as the default pump. If this field is left with a dash then the TSF pump will remain on at the completion of the rating. When using a default pump LabCON will automatically adjust the compression to avoid excessive knocking at the rating completion. Use the F1 key to toggle Yes or No. If set to Yes, all pumps Core Lab Refinery Systems 32 T-EIOM.8035 Rev 008

40 Sample Data Field Use Previous PRF Fuel/Air? Sample Identifiers Pumps 1 to 4 Fuel Pump Sequence 1st, 2nd, 3rd, etc. Octane No. Action/Description selected will be run for a 20 second flush period at start of the first pump in the sequence. Use the F1 key to toggle Yes or No. If set to Yes, then any previously run PRF fuel/air s will be used as the fuel/air set point. A previous fuel/air set point must be within octane numbers and run within the last 24 hours to be eligible for reuse. Note: All previous fuel/air values are deleted after powering down the LabCON computer. Type in the identifier of the fuel being run in the pump. Most alphanumeric characters are allowed. The data can accessed later using this identifier. The default identifiers are samp(n), where "n" is the pump number. Up to 6 characters are accepted as an identifier. Note: Only the last default ID's are saved, as the next default will overwrite the old data. A pump sequence must be entered, there isn t a default sequence. The pump sequence can be any order and up to six fuels can be scheduled. See the examples illustrated in the next section titled Fuel Pump Sequences. The PRF used in the rating is identified by entering the PRF octane number below the corresponding PRF pump number in the sequence. See the examples illustrated in the next section Fuel Pump Sequences. Be sure to leave this field blank to identify the pump as containing an unknown sample. Upon completion of the data entry process selecting function key F8 will instruct LabCON to perform the rating. Before LabCON starts the rating process, it will examine all the entered data for completeness and accuracy. If any of the data is suspect, LabCON will display an error message explaining the condition. For example, entering in a value of 10.0 for the barometric pressure would cause LabCON to issue an Invalid Barometric Pressure message. To acknowledge the message press the F9 key and at this time you must enter in a valid barometric pressure value and press F8 again. Occasionally after pressing the F8 run key LabCON will generate a warning report which displays low priority messages. These messages can be ignored by pressing the F1 Ignore key or the data can be changed by pressing the F2 Change key. At any time before starting the rating you can Core Lab Refinery Systems 33 T-EIOM.8035 Rev 008

41 press the function key F7 to recall all the entered data from the previous rating. This tool is helpful to eliminate repetitive data entry when the entered data is similar from rating to rating. In addition, the F6 key displays the Advanced Setup display which allows changing some less frequently used parameters. See the section titled CR Rating Advanced Setup for further details. Pressing the function key F10 during the data entry process will display a context sensitive help window to assist you. 8.9 Fuel Pump Sequences A fuel pump sequence must be entered since there isn t a default sequence. The pump sequence can be in any order and up to six fuels can be scheduled. Example 1 illustrates one PRF and three samples to be run. The sequence below instructs LabCON to run pump number 2 first, followed by pumps 1, 3, and 4. Pump number 2 contains a primary reference fuel of 91.0 octane and the other pumps contain a sample of unknown octane. If any Octane No. field is left blank LabCON assumes that an unknown sample is to be run in the corresponding pump above. The dash in the 5th sequence slot indicates the end of the fuel pump sequence. Example 2 illustrates one primary reference fuel and three samples are to be run by LabCON. However, by selecting pump number 2 again 5th in the sequence you can verify if the reference fuel s set point had changed during the course of the ratings. When repeating reference fuels, LabCON will not run a complete test on the second scheduling of the PRF, it will only re-establish the KI set point. Core Lab Refinery Systems 34 T-EIOM.8035 Rev 008

42 LabCON can also rate samples in different octane ranges in the same group by scheduling a second PRF pump with a different octane number associated with it. In example 3 a PRF of 84.0 octane is run first followed by an unknown sample. Immediately following a PRF of 88.0 octane is run followed by an unknown sample of assumed higher range. The reference fuel, if present, must always be scheduled to run first and then the sample. A PRF is not required if the reference fuel s set point has been previously determined. If the reference fuel s set point has already been determined simply enter the values into the PRF KI Set point field and PRF Octane Number fields as explained in the Sample Data Entry section Sample Rating Report The following example shows the final rating results of a primary reference fuel and two unknown samples. The reference fuel has been identified as PTEST12. The identifier PTEST12 is also stored with the unknown sample in history so as to identify the reference fuel when displaying only the sample from history. A default spread of 10.0 knock meter units was used to eliminate small dead band errors. PRF KI set points of 45.3 and 46.2 were arrived at on the reference fuel and they were used to determine the two octane number readings on the sample. The final octane number was then averaged from the two readings and rounded to the nearest even tenth of an octane number. At this time, pressing the function key F1 will Core Lab Refinery Systems 35 T-EIOM.8035 Rev 008

43 print a report to an attached printer CR Advanced Setup In addition to the standard data entry display, the advanced setup option also contains data parameters which may be changed. The advanced setup display is accessed by selecting function key F6 at any time during the data entry process. The advanced setup display contains parameters which may need not be changed from rating to rating. The parameters available are; FUEL FLUSH TIME, PERFORM SPREAD CHECK, SEARCH NARROW ONLY, and REPEAT READING. The advanced setup parameters are set to defaults during the system setup process and are saved permanently to the engine configuration file when changed by the LabCON operator. Advanced Setup Defaults Advanced Setup Parameter Default Fuel Flush Time 0 Perform Spread Check Search Narrow Only Repeat Reading NO YES NO The fuel flush time when increased from 0 seconds adds time to the fuel flush period when the fuel pump is first turned on. Some fuels may cause the engine to respond much slower, such as ones that contain TEL. If this is the case, you can increase the total fuel flush time by setting the desired time in this field. The time entered in this field is added to the default fuel flush time already used by LabCON. The standard fuel flush times during a CR method rating are 30 seconds for a PRF or unknown sample, and 50 seconds for a Core Lab Refinery Systems 36 T-EIOM.8035 Rev 008

44 toluene standard fuel. The standard fuel flush times during a bracketing method rating are 45 seconds for a PRF or unknown sample, and 50 seconds for a toluene standard fuel. The number of seconds entered into the fuel flush period field is added to all of the fuels standard flush time. The perform spread check option is there to reduce overall rating time during a sample sequence. When this option is set to YES, a spread check is performed on each PRF run in a batch of fuels. The spread is determined by increasing the compression ratio for 2 seconds (approximately 20 DC units) and dividing the knock intensity difference by the octane difference of the two CR positions. This value is then later used by LabCON (CR method rating only) to reduce the error caused by the sample KI set point not exactly equaling the PRF KI set point. Since this error is very small, and in most cases will amount to hundredths of an octane number, LabCON is able to use default spread values in lieu of exact spread values. When setting this option to NO, LabCON uses a spread value of 10 KI units for the motor method engine and 15 KI units for the research method engine. Using these default values can reduce the overall rating time by up to 4 minutes. The search narrow only parameter when set to YES will instruct LabCON to only perform a fuel/air ratio search procedure using the fine or narrow increments. This value in most cases should be set to YES to reduce overall rating times. If LabCON has no history of a valid fuel/air starting point to use, both the broad and narrow fuel/air increments will be used during the fuel/air ratio search procedure. The repeat reading parameter when set to YES, instructs LabCON to repeat each fuel in the sequence. If there are two fuels in the sequence, then LabCON will take 4 readings, 2 for each fuel. Upon completion of the rating, LabCON will display the octane number for each set of readings and also display the average of the two results. In 1997, the ASTM Book of Standards has indicated that this is the preferred method for running a CR method octane rating. However, the method does also mention that it is permissible to avoid repeating the rating under certain circumstances. Consult the ASTM Book of Standards for further information. Core Lab Refinery Systems 37 T-EIOM.8035 Rev 008

45 9.0 CR METHOD OCTANE RATING DETAILS LabCON-V Operating Manual 9.1 General The primary reference fuel, if present, must be scheduled to run first and then the sample or toluene standard fuel. A reference fuel is required when rating a toluene but is not required in a sample group. A previously determined reference fuel set point can be entered manually for a sample group. The rating procedure for toluene and a gasoline sample are the same, except for an additional check on toluene to determine if the final result is within the tolerances of the toluene calibrated octane. The fuel sequence depends on whether CR Toluene Rating or CR Sample Rating was selected from the Octane Analysis Menu. If the toluene rating was selected, then a TSF will be the next fuel to run. If the sample rating was selected, then a sample will be selected in the order specified on the sample setup screen. 9.2 Preliminary Adjustments A flushing cycle is run on any new fuel to assure that no traces of the previous fuel remain. If the fuel is a known reference fuel, immediately following the flushing cycle the compression motor is driven to the guide table value for the fuel s octane number. The prevailing barometric pressure is used to offset the compression ratio position. After the compression adjustment, LabCON will wait for the engine s knock intensity to stabilize and then proceed with the fuel/air ratio search procedure. If the fuel is an unknown sample, the compression will not be adjusted unless the knock is too high or low to initiate a the fuel/air search procedure. If CR adjustment is required on a sample, LabCON will adjust the compression to obtain a knock intensity within the 35 to 65 range. At this time LabCON will wait for the engine to reach equilibrium before starting the fuel/air ratio search procedure. Core Lab Refinery Systems 38 T-EIOM.8035 Rev 008

46 9.3 Fuel/Air Search Procedure A fuel/air search is Knock Intensity Microvalve Fuel/Air Position the process in which LabCON moves the fuel microvalve in precise steps, calculated for direction, until a peak knock intensity is achieved or can be calculated. LabCON usually starts a fuel/air search procedure by setting the microvalve to a previously known setting for that fuel. This helps to obtain substantial knock from the engine before actually starting the microvalve movement logic. If the fuel is a PRF, then LabCON checks to see if a PRF has been run previously within one octane of the current PRF. If so, then LabCON can re-use this value and avoid the fuel/air ratio search. This option is selectable during the sample data entry procedure. By using statistical regression analysis, LabCON can determine the optimum fuel/air ratio setting for the microvalve without actually arriving at the position during the procedure. The fuel air search plot shown depicts a fuel air search with 17 different microvalve positions. LabCON can determine that 146 is the optimum fuel/air position with as little as 3 different microvalve positions. At the completion of the fuel/air search, a stability check is performed by calculating the knock intensity stability over a prescribed time period. After the knock stabilizes LabCON will continue with the rating. Core Lab Refinery Systems 39 T-EIOM.8035 Rev 008

47 9.4 Final Adjustments The final check on the reference fuel is the knock intensity spread check. However, this check can be bypassed to decrease the overall rating time (See advanced setup options). If there is no reference fuel in the sample group, then the check is conducted on the first sample. This check is performed to calculate the number of knock units equal to one octane number. The spread value is then used later to eliminate small Move CR to Table Value. Movetoknown F/A. Start Sequence. Is Reference Fuel? Previous F/A Available? LabCON-V Operating Manual Move CR for sufficient knock. compression adjustment dead band errors. The check is performed by reading the cylinder head s position and KI before and after a head adjustment. After the spread check is complete, LabCON will monitor the knock until the engine reaches equilibrium. If the knock is within the range of 40 to 60 KI, LabCON will save the current knock as the set point for later use. If the KI is outside the 40 to 60 range, LabCON will prompt with the message Adjust KI to Mid-Scale. At this time the detonation meter setting should be adjusted to obtain a knock of approximately 50 on the meter. This knock set point will be the target knock when adjusting the compression ratio for a toluene standard fuel or an unknown Yes Yes Perform Spread Check (if enabled). Obtain KI Setpoint. Yes No No Fuel Flush Period. PerformF/A Search (if req'd). Is Reference Fuel? No Control KI toprf Setpoint. Calculate Results. Is Repeat Enabled? No View Results. Yes Core Lab Refinery Systems 40 T-EIOM.8035 Rev 008

48 gasoline sample. After achieving a reference fuel set point, a new fuel is selected and a similar series of events occur; fuel flush period, compression ratio adjustment, fuel/air ratio determination, final CR adjustments, and final octane calculations. 9.5 Octane Number Tolerance The octane number of the sample is not acceptable if it differs by more than the appropriate value given below from the octane number of the reference fuel blend last used to establish standard knock intensity. Octane Number Range Maximum Permissible Difference (Reference Fuel & Sample) Below to to to Above NOTE: When the above parameters are exceeded, LabCON will generate the message "Sample rated out of tolerance from PRF". At this time you should run another reference fuel closer in octane to the sample. LabCON makes use of an extensive array of alarms to monitor conditions and engine data during a test. A complete list of these alarms and resulting actions is shown in the section title Alarms. Core Lab Refinery Systems 41 T-EIOM.8035 Rev 008

49 10.0 BRACKETING METHOD OCTANE RATING LabCON-V Operating Manual 10.1 General The Bracketing Method is thought by some to be a more stable and reliable method of determining final octane; however, it can also be more time consuming. Unlike the Compression Ratio Method, where the octane is read from a table for the cylinder height, the bracketing method requires multiple readings on three fuels as opposed to two. This method takes a knock meter reading for the sample at a constant compression ratio and brackets between the knock meter readings for the two reference fuels. The octane of the sample is then calculated by mathematic interpolation. To make this method more effective for routine ratings, while maintaining precision and accuracy, some deviations from the method are available. However, it is strongly recommended that the full rating process be used for final or certified ratings Bracketing Method Data Entry The bracketing method utilizes different data entry displays for data input and final reports than the CR method. However, it has the same look and feel as the other data entry displays. The Enter and Arrow keys are used to navigate from field to field and the F1 key is used to toggle fields between Yes or No. Upon completion of data entry the F8 key is used to verify all entered data and start the rating. The F7 key is used for retrieving all entered data from the previous rating. To Core Lab Refinery Systems 42 T-EIOM.8035 Rev 008

50 obtain on line help with a data field press the F10 key while the cursor is in the corresponding data entry field. Pressing F10 again will exit from the help window. Bracketing Data Entry Parameters Field Barometric pressure Intake Air Temperature (RON) Mixture Temperature (MON) Default Pump Global Pump Purge? Use Previous PRF Fuel/Air? Force Sample S2 SP? Search 1st PRF Only? Action/Description Enter the present barometer reading or if a pressure transducer is installed the current pressure will be displayed. This value will be used to offset the CR guide table to 29.92" Hg. Press F1 to retrieve the correct intake air temperature for the barometric pressure entered previously. Press Enter to accept the recommended temperature or F1 to enter another temperature. Press F1 to view the allowed mixture temperature range. The recommended ASTM range is 285 to 325 degrees Fahrenheit. LabCON will accept a value from 250 to 350 degrees. Enter a pump to be turned on at the completion of the rating. If entered, the pump will be turned on when the rating is finished. Any pump number from 1 to 4 can be used as the default pump. If this field is left with a dash then the TSF pump will remain on at the completion of the rating. When using a default pump LabCON will automatically adjust the compression to avoid excessive knocking at the rating completion. Use the F1 key to toggle Yes or No. If set to Yes, all pumps selected will be run for a 20 second flush period at start of the first pump in the sequence. Use the F1 key to toggle Yes or No. If set to Yes, then any previously run PRF fuel/air s will be used as the fuel/air set point. A previous fuel/air set point must be within octane numbers and run within the last 24 hours to be eligible for reuse. Note: All previous fuel/air values are erased when the LabCON is powered off. Use the F1 key to toggle Yes or No. If set to Yes, LabCON will adjust the compression ratio if the final knock of the second sample is outside the 45 to 55 KI range. This is a requirement by ASTM but can be overridden by setting this option to No. If LabCON adjusts the CR on the second sample the reference readings must be re-sampled thereby extending the overall rating time. Use the F1 key to toggle Yes or No. If set to Yes, LabCON will only perform a fuel/air search on the first reference fuel in the Core Lab Refinery Systems 43 T-EIOM.8035 Rev 008

51 sequence. The second reference fuel in the sequence will use the fuel/air value determined on the first reference fuel. If this option is used with the Use Previous PRF Fuel/Air option, LabCON will use same fuel/air value for both reference fuels even if the first reference was not searched. S2 Shortcut? Sample Identifiers Pumps 1 to 4. Fuel Pumps - Sample One Fuel Pumps - Low PRF Fuel Pumps - High PRF Fuel Pumps - Sample Two Max Readings *TSF O.N. Use the F1 key to toggle Yes or No. If set to Yes, LabCON will run sample two back to back with sample one when the KI is between 40 & 60 and Force Sample S2 SP has not been selected. This technique re-uses the reference fuel readings from the first sample on the second sample. This will cut down on overall rating time (by 2 reference fuel readings - approximately 4 minutes) but will deviate from the ASTM method of bracketing analysis. Type in the identifier of the fuel being run in the pump. Most alphanumeric characters are allowed. The data can accessed later using this identifier. The default identifiers are brack(n), where "n" is the pump number. Up to 6 characters are allowed as the identifier. Note: Only the last default ID's are saved, as the next default will overwrite the old data. Enter the pump number of the first unknown gasoline sample. Enter the pump number of the lower octane primary reference fuel. Enter the pump number of the higher octane primary reference fuel. Enter the pump number of the second unknown sample. Enter the number 1..3 which will define the maximum number of readings LabCON will perform on each fuel. To comply with ASTM standard this number should be set to 3. When the readings parameter is set to 3, under normal conditions LabCON will only perform 2 readings. To decrease the overall sample rating time set this number to 1. When running a toluene standard fuel enter the known octane number of the standard. Leave this field blank if you are running a gasoline sample. IMPORTANT NOTE: When using the F7 Recall option LabCON will NOT retrieve this field. This is to prevent running a sample as a TSF accidentally. Core Lab Refinery Systems 44 T-EIOM.8035 Rev 008

52 Upon completion of the data entry process selecting the F8 function key will instruct LabCON to perform the rating. Before LabCON starts the rating process, it will examine all the entered data. If any of the data is suspect, LabCON will display an error message explaining the condition. For example, entering in a value of 450 for the mixture temperature would cause LabCON to issue an Invalid Mixture Temperature message. To acknowledge the message press the F9 key. At this time you must enter in a valid mixture temperature and press F8 again. Occasionally after pressing the F8 run key, LabCON will generate a warning report which displays low priority messages. These messages can be ignored by pressing the F1 Ignore key or the data can be changed by pressing the F2 Change key. A typical warning message may be informing you that a sample identifier will be overwritten in the history directory. At this time if you wanted to avoid overwriting a history file you would change the identifier. Data entry help is available at any time by pressing the F10 help key when the cursor is in the data entry field. To decrease the time needed for data entry you can press the F7 Recall key to retrieve all the data entered during the last sample setup and simply change the required parameters. When using the recall option, LabCON never retrieves the *TSF O.N. field. This is by design so that a blind sample won t be run as a TSF in error Bracketing Method Advanced Setup In addition to the standard data entry display, the advanced setup option also contains data parameters which may be changed. The advanced setup display is accessed by selecting function key F6 at any time during the data entry process. The advanced setup display contains parameters which may need not be changed from rating to rating. The parameters available are; FUEL FLUSH TIME, FUEL RUN IN TIME, and SEARCH NARROW ONLY. The advanced setup parameters are set to defaults during the system setup process and are saved permanently to the engine Core Lab Refinery Systems 45 T-EIOM.8035 Rev 008

53 configuration file when changed by the LabCON operator. LabCON-V Operating Manual Bracketing Advanced Setup Defaults Advanced Setup Parameter Default Fuel Flush Time 0 Fuel Run In Time 120 Search Narrow Only YES The fuel flush time when increased from 0 seconds adds time to the fuel flush period when the fuel pump is first turned on. Some fuels may cause the engine to respond much slower, such as ones that contain TEL. If this is the case, you can increase the total fuel flush time by setting the desired time in this field. The time entered in this field is added to the default fuel flush time already used by LabCON. The standard fuel flush times during a bracketing method rating are 45 seconds for a PRF or unknown sample, and 50 seconds for a toluene standard fuel. The number of seconds entered into the fuel flush period field is added to all fuels standard flush time. The fuel run in time parameter defines the time period that LabCON will remain monitoring a fuel before acquiring the final knock intensity readings. The normal time period is set to two minutes and will satisfy the equilibrium requirements for most fuels. If you find that the fuels being run require more or less time you can adjust this parameter accordingly. Use caution when decreasing this time period as it can affect the accuracy of the final octane number. LabCON will accept values from 90 to 240 seconds. The search narrow only parameter when set to YES, in most cases will force LabCON to only perform a fuel/air ratio search procedure using the fine or narrow increments. This value in most cases should be set to YES to reduce overall rating times. If LabCON has no history of a valid fuel/air starting point to use, both the broad and narrow fuel/air increments will be used during the fuel/air ratio search procedure. Core Lab Refinery Systems 46 T-EIOM.8035 Rev 008

54 10.4 Temperature Tuning - (Toluene Repeat Option) To take advantage of the TSF temperature tuning option, you must remain on the sample results screen. Temperature tuning is accomplished by adjusting the appropriate temperature on the engine as necessary (intake air temperature on RON or mixture temperature on MON) and repeating the rating by pressing the repeat function key F8. At this time a window will appear with the prompt Enter the new temperature: The toluene repeat function will not perform a fuel/air search and will remain on each fuel for the run-in time specified in the advanced setup display. Upon completion of the toluene repeat, the new calculated octane will be displayed. If you still do not receive a passing status message (view the status message by pressing the F2 function key) then you can continue raising or lowering the engine temperature until the correct octane is achieved. When adjusting the engine temperature be sure to allow enough time for the engine temperature to stabilize after each temperature adjustment. Remember when adjusting the temperature, that increasing the temperature decreases the octane number and the exact opposite occurs when decreasing the temperature. For the research engine, vary the temperature approximately 10 Fahrenheit to achieve a rating change of 0.1 to 0.2 octane numbers. For the motor engine, vary the temperature approximately 2 Fahrenheit to achieve a rating change of 0.1 octane numbers. Core Lab Refinery Systems 47 T-EIOM.8035 Rev 008

55 10.5 Final Report The bracketing final report displays final octane numbers on up to two samples. In addition to the octane number results, various other data is displayed. With the knock data readings supplied by the report, you can calculate the average octane number or read it from the display. The knock readings are displayed in a tabular format for each sample. The report on this page shows data for 1 reading taken on a single sample. The data shown under the Readings section of the report is what LabCON used to calculate the final octane number by method of interpolation. If more than one reading is taken on the fuels then the additional data is shown in the second and thirds rows below the first. Up to three readings may be taken on each fuel if necessary. The number of readings taken is controlled by the Max Readings parameter on the data entry display. Pressing the F1 function key will print the final report to an attached printer. If you had run a toluene standard fuel you would be given the opportunity to view the status message by pressing F2 or the option to repeat the rating by pressing F7. Core Lab Refinery Systems 48 T-EIOM.8035 Rev 008

56 11.0 BRACKETING METHOD OCTANE RATING DETAILS LabCON-V Operating Manual 11.1 General This section describes in detail the bracketing rating procedure performed by LabCON. Up to two unknown samples can be determined in sequence using this method. The sample is run first in the sequence and standard knock intensity is established. After standard knock intensity is reached the next fuel run through the engine is the lower octane primary reference fuel. Again, standard knock intensity is determined and the knock intensity results are stored for the final calculations. Next, the higher octane primary reference fuel is run through the engine and standard knock intensity is reached. After storing the results, the test will end with an octane rating report or the complete fuel sequence will be repeated up to the number of times specified during the data entry procedure. If multiple readings are performed, the results are displayed in a table and the average octane number is calculated and reported Preliminary Adjustments A flushing cycle is first run on any fuel to assure that no traces of the previous fuel remain. This period also allows the engine to initially respond to the fuel. The normal flush period is 45 seconds for a PRF or sample and 50 seconds for a TSF. These times can be extended by entering in an additional flush period in the advanced setup. During the flush period LabCON proceeds through a series of checks to determine an approximate fuel/air ratio of the fuel. For example, if the fuel is a PRF and LabCON has run a PRF within the last 24 hours in close proximity to the octane of the current PRF then the known fuel/air position will be used. This option is only used when the Use Previous Fuel/Air parameter is set to YES. This feature helps the engine stabilize much quicker and in most cases will reduce the overall rating time significantly. If a previous fuel/air position is not available then LabCON will make use of the stored fuel/air averages. A separate average microvalve Core Lab Refinery Systems 49 T-EIOM.8035 Rev 008

57 position is stored and maintained for the primary reference fuels and unknown samples. If the average is unavailable (reset to 0), then LabCON only guesses that a sample fuel operates at a leaner fuel/air ratio then a reference fuel. No assumptions are made if running a PRF and no historical fuel/air ratios are available. If the fuel is a sample, then compression control will be performed at the end of the flush period to achieve a suitable knock of 35 to 65 knock meter units. Once the knocking condition is stable then the fuel/air ratio search will begin Fuel/Air Search Procedure A fuel/air search is the process in which LabCON moves the fuel microvalve in precise steps, calculated for direction, until a peak knock intensity is achieved or can be calculated. LabCON usually starts a fuel/air search 48 procedure by setting the microvalve to a previously known setting for that fuel. This helps to obtain substantial knock from the engine before actually starting the microvalve movement logic. If the fuel is a PRF, then LabCON checks to see if a PRF has been run previously within Knock Intensity Microvalve Fuel/Air Position one octane of the current PRF. If so, then LabCON can re-use this value and avoid the fuel/air ratio search. This option is selectable during the sample data entry procedure. By using statistical regression analysis, LabCON can determine the optimum fuel/air ratio setting for the microvalve without actually arriving at the position during the procedure. The Core Lab Refinery Systems 50 T-EIOM.8035 Rev 008

58 fuel air search plot shown depicts a fuel air search with 17 different microvalve positions. LabCON can determine that 146 is the optimum fuel/air position with as little as 3 different microvalve positions. During the search LabCON will monitor the knock after each movement to detect a sharp decrease in KI. If this occurs, then the logic will advance to the next movement. This is to prevent the engine from knocking at severely lean or rich conditions. For example, if the engine is knocking at 40 units and a lean movement is initiated, if the knock drops 10 units within 10 seconds of the move, then LabCON immediately drives to a much richer fuel/air ratio to correct this condition. At the completion of the fuel/air search, a stability check is performed by calculating the knock intensity stability over a prescribed time period. After the knock stabilizes LabCON will continue with the rating Final Adjustments After the fuel/air search is complete, LabCON will wait a 60 second period for the engine to reach equilibrium and maintain standard knock intensity. If the fuel is a primary reference fuel then an average is calculated over a specified period of time. If the fuel is a sample, then CR control is performed to achieve an approximate knock of 50 units. Again, LabCON waits for the engine to reach equilibrium. At this time an average knock is then calculated over a specified period of time. Upon completion of the fuel the next fuel is switched on in the sequence and the process is repeated Fuel Sequencing When running the bracketing method LabCON can perform up to 3 readings on every fuel in the sequence. A sequence consists of running all the fuel pumps listed on the data entry display once. ASTM recommends running a sequence twice and average the results to attain an accurate octane number. In addition, if the two individual readings differ by more than a specified tolerance than a third reading should be taken. The standard Core Lab Refinery Systems 51 T-EIOM.8035 Rev 008

59 sequence (two readings) for a single sample is shown in the illustration below. Standard Fuel Sequence for a Single Rating S1 - P1 - P2 - S1 - P2 - P1 The S1 is sample one followed by P1 which is the low octane reference fuel. Third in the sequence is P2 which is the higher octane reference fuel. The lower octane PRF must have a higher standard knock intensity than the sample whereas the higher octane PRF must have a lower standard knock intensity than the sample. If these conditions are not met, than the test will end prematurely with an error message. If the conditions are met then the sequence is repeated as illustrated above. LabCON supports a small variation to the standard fuel sequence when rating two samples. It includes using the PRF readings from sample one to calculate results on sample two. This technique is only applied when the two samples are in the same octane range. The standard fuel sequence for a dual rating is shown in the illustration. Standard Fuel Sequence for a Dual Rating S1 - P1 - P2 - S1 - P2 - P1 - S2 - P1 - P2 - S2 - P2 - P1 As you can see by the complexity of the sequence, these readings could take a considerable amount of time to complete. Therefore LabCON incorporates the S2 Shortcut option to eliminate two of the readings. This method will reduce the overall rating time for Core Lab Refinery Systems 52 T-EIOM.8035 Rev 008

60 S2 Shortcut Fuel Sequence for a Dual Rating S1 - P1 - P2 - S1 - P2 - P1 - S2 - P1 - P2 two samples by approximately 4 minutes. In cases where a single octane estimate is desired, a short sequence can be used. Short Fuel Sequence for a Single Rating S1 - P1 - P2 Using the short sequence can give you an octane number estimate and assist you in mixing the appropriate PRF for a standard rating sequence. The number of readings taken on the fuel sequences is selectable by changing the max readings parameter on the data entry display. Core Lab Refinery Systems 53 T-EIOM.8035 Rev 008

61 12.0 PROTOTYPE CALIBRATION 12.1 Description The Prototype Calibration procedure is used to determine the octane number of an unknown prototype tank as defined by the ASTM D-2885 standard. Although LabCON is a laboratory analyzer, the derived octane of the prototype tank is used for on-line blend monitoring purposes. LabCON uses a standard fuel (or golden prototype) of known octane number and compares the knock characteristics of the known octane to the knock characteristics of the unknown octane number and determines the average octane number. The proto calibration requires a considerable amount of time to complete and performs many cyclic comparisons of the known and unknown fuels. All data acquired by LabCON during the test is stored in history for later review and hardcopy reporting. Data entry of the required parameters for the proto calibration is similar to the laboratory rating procedure Preparation To perform the calibration exercise, ample amounts of the standard fuel and the prototype fuel should be available for about 2 hours of operation (1 hour on prototype fuel and 1 hour on standard fuel). These quantities should be stored in cans next to the LabCON sample shelf close enough to the sample probes for easy fuel delivery. The engine should be warm and the compression ratio should be set to that of the standard fuel s octane number as defined by the ASTM guide table. See the ASTM manual section D-2885 for further fuel handling procedures Data Entry The proto calibration data entry display is accessed by selecting F1 followed by F4 from the Main Menu. As in all laboratory ratings, a pump must be selected and the Core Lab Refinery Systems 54 T-EIOM.8035 Rev 008

62 microvalve must be initialized before entering a data entry display. The data entry display has a similar look and feel as the sample rating displays. To retrieve the information entered during the last calibration select the F7 function key. To start the calibration exercise select the F8 function key. The proto calibration is identified in history by the tank identifier. The tank identifier field accepts up to 5 alpha-numeric characters and is required before LabCON will start the calibration exercise. The standard fuel pump and the prototype pump fields must contain the pump numbers 1 to 4 which identify the pump to use respectively. The default pump is turned on at the completion of the proto calibration. The standard octane number field Core Lab Refinery Systems 55 T-EIOM.8035 Rev 008

63 contains the octane number of the standard fuel. This number should be the average octane of many laboratories rating the same fuel. The standard auto f/a option, if turned on, tells LabCON to perform a fuel to air ratio search function to determine standard knock intensity on the standard fuel. If this option is not set to YES then a manual fuel air entry must be entered. The prototype auto f/a, option if turned on, instructs LabCON to perform a fuel to air ratio search procedure to determine standard knock intensity on the prototype fuel. If this option is not set to YES then a manual fuel air entry must be supplied. The analysis method is changed by pressing the F1 key to toggle between KI Method and CR Method. Both methods are accepted by ASTM as valid tests to determine the prototype octane number. The knock intensity spread field is required when using the KI method of analysis. Enter the number of knock meter units equal to one octane number in this field. Acceptable spread values are from 5 to 50 knock units. When running the CR Method of analysis, the CR spread is determined from the ASTM compression ratio guide table. After data entry is completed press the F8 function key to start the proto calibration function. LabCON will check all the entered data and produce an error message if any data field is in error Prototype Calibration Details LabCON starts the proto calibration by turning on the pump with the standard fuel. If an automatic fuel air search has been selected then a fuel air search is initiated. If a prototype fuel air search has been selected then the prototype search is initiated subsequently. At the completion of the fuel air search LabCON cycles from standard to prototype fuel 26 times to determine the individual knock and compression ratio average values for each fuel. Each fuel cycle entails 2 minutes of fuel delay and 2 minutes of fuel sampling to total 4 minutes in length. The entire process requires 104 minutes of fuel cycling time. The first 6 cycles are not included in the prototype octane running average. During the calibration, the cycle number, the cycle octane number, and the running average octane number will be displayed at the bottom of the graphical knock display. Core Lab Refinery Systems 56 T-EIOM.8035 Rev 008

64 12.5 Final Report The proto calibration report is displayed upon completion of the test. Each fuel cycle s data is displayed in a row and column format for detailed examination. To view all 26 cycles use the up and down arrow keys to scroll the display. The final octane number will be inserted in the Final Proto Octane field. If the proto calibration was not run to completion (i.e. operator aborted after 20 cycles), than the last running average in the table can be used for estimation purposes. To print the report to an attached printer press the F1 function key Calibration History The proto calibration history reports are viewed from the sample history option in the utilities menu. After displaying a sample history list select the F7 function key to switch between the 3 history file directories; CR Sample History, Bracketing Sample History, and Proto Calibration History. Once the proto calibration history list is displayed, select the desired history report and press Enter. The report will be displayed and can be printed at this time. Core Lab Refinery Systems 57 T-EIOM.8035 Rev 008