TDG-F-113 CEC New Test Development Proposal for a New Engine Fuels Test Procedure DISI (Direct Injection spark ignited engine) Injector fouling Test 1. Demonstrated need- The proposed test will address injector deposits in direct injection spark ignited engines (DISI) and the deposit control ability of gasoline. Injector fouling influences the spray pattern and the injected fuel volume of the injector and therefore affects directly the driveability and performance and the exhaust gas emissions of the vehicle. Since the last decade DISI-engine equipped vehicles captured a mentionable market share in Europe and worldwide. Gasoline direct Injection and supercharging will be key measures to optimise the fuel efficiency of future engine. Injector cleanliness is one of the basic requirements to fulfil the different demands concerning driveability, performance and exhaust gas emissions even with a higher mileage. The introductions of more stringent vehicle emissions legislation will challenge to an engine/injector design with a higher sensitivity concerning any deposit formation. To fill that gap gasoline with a suitable deposit control ability will become more and more important. Current DCA ( Deposit Control Additives) engine performance tests are based on port fuel injection engines (PFI) with the assessment of the IVD (intake valve deposits) and the assessment of the deposit formation at port fuel injectors. A read across of PFI engine test results to predict the DCA ( Deposit Control Additives) performance in a DISI-engine is limited due to different ambient conditions (temperature, pressure, combustion gases, flow behaviour) at the injector tip. For a definition of a DISI-DCA ( Deposit Control Additives) performance a new test is required to be able to discriminate between fuels that generate low and high injector deposits formation, as high injector deposits formation fuels are not able to keep the injector clean enough to run the engine in compliance with the above mentioned requirements. The CEC test development will build on the in-house test procedure developed by Volkswagen. The CEC is not aware of any other official engine test procedure to evaluate DISI-DCA ( Deposit Control Additives) performance of gasoline. In the early 2000, an attempt to develop a similar test using a Mitsubishi engine was not conclusive. 2. Endorsement The members of the European automobile industry association (ACEA), European Fuel association (Concawe) and Additive industry association (ATC) give their full support to this new candidate test procedure. 3. Availability of Support The test engine is a widespread used version of the EA111 engine developed by Volkswagen AG, and will be available in production for at least five years after completion of the development of the test. Production of the engine is guaranteed until 2019. For CEC purposes, the availability of engines/parts will be secured beyond that date VW is the source of the hardware requirements for installing and running this candidate CEC test. Fuel and engine specialists of Volkswagen AG will provide technical support on the hardware, lubricant and fuel requirements of this engine during the development phase, including advice on reference fuels, and also if necessary once the test has been established. It is intended that advice will be given on setting up and running the engine on test benches. A sealed engine control unit will be made available to the laboratory installing the test. 2016/9/15 Final Version Page 1 of 7
4. Confidentiality The information provided to the CEC Project Group will be confidential where it pertains to the electronic engine control unit. The information provided by Volkswagen AG will also be confidential where it pertains to the design of the engine. The information so provided should be protected in the documented proceeding of the Group by the relevant CEC declaration. It is not intended that other OEM companies or fuel injection suppliers should be excluded from the test development and test use by this constraint. 2016/9/15 Final Version Page 2 of 7
1. General CEC New Test Development Terms of Reference Vehicle manufacturers are increasing the market share of direct injection spark ignited engines (DISI) to meet the demands of legislative regulations and the demands of car drivers. DISI engines offer multiple advantages over common port fuel injection engines (PFI) but they can be susceptible to deposit formation even at fuel injector nozzle. Fuel injector deposits have been identified as root cause for a number of negative effects that can impact the normal operating mode of the engine. New exhaust emission legislative activities may require injector types with a higher dependency on fuel DCA ( Deposit Control Additives) performance even for higher mileage. Industry DCA ( Deposit Control Additives) performance tests are solely designed for port fuel injection engines (PFI) with the assessment of the IVD (intake valve deposits) and the assessment of the deposit formation at port fuel injectors. An extrapolation of PFI engine test results to predict the DCA ( Deposit Control Additives) performance in a DISI-engine is limited due to different ambient conditions (temperature, pressure, combustion gases, flow behavior) at the injector tip. For this reason a new test is required that is able to discriminate between a fuel that produces no significant injector deposits and one which cannot prevent injector fouling and as such is not able to keep the injectors clean enough to run the engine in compliance with the above mentioned requirements. The CEC is not aware of any official engine test procedure to evaluate the effects of DISI injector fouling that is representative of the present and future risks due to injector fouling. In the early 2000, an attempt to develop a similar test using a Mitsubishi engine was not conclusive. Expected goals for the test development are: The test is required to be able to discriminate between a fuel that produces no significant injector deposits and one which cannot prevent injector fouling and could cause drivability issues due to a severe increase of the injection time (example figure 1). Another parameter to reflect potential drivability issues is A/F ratio A testing tool for gasoline additives performance based on a widespread used engine Develop a reliable and safe test with good precision The test should facilitate a practical, adoptable and easily understandable limit setting. A fully qualified CEC test procedure should be developed: o Test must be able to discriminate between calibration fuels of known field performance on the chosen parameters as per CEC requirements. o Test repeatability and reproducibility must meet CEC requirements. Timing target for completion of test development must be defined The laboratory chosen to lead the test development must: Meet CEC quality requirements. Registered office and test benches must be situated in Europe Have experience of running engine tests. 2016/9/15 Final Version Page 3 of 7
2. Test Hardware As test hardware operates a widespread turbocharged direct injecting engine of the EA111 family. The test engine has the highest power stage of this type series (maximum of downsizing). The 1.4 litre TSI Engine was first used in the fifth generation of the Volkswagen Golf. It combines a supercharger for low end torque with a turbocharger and direct injection technique. The test engine is sensitive to DISI injector fouling, thereby the EA111 engine seems to be suitable for test development. Table 1 lists some basic properties of the test engine. Engine Code BLG Type 4-cylinder in-line engine Displacement 1390 Bore 76,5 Stroke 75,6 Valves per Cylinder 4 Compression Ratio 10:1 Maximum Output 125 KW @ 6000 rpm Maximum Torque 220 Nm at 1750-4500 rpm Engine Management Bosch Engine Management Fuel Exhaust Gas Treatment Emission Standard Super Plus at RON 98 (Super unleaded at RON 95 with slightly higher consumption and torque reduction in the low rev ranges) Main catalytic converter, Lambda control EU4 Table 1: Test Engine Properties The Fuel system is fully demand controlled. The injection pressure is supported by a camshaft-driven single-piston high-pressure injection pump supplying up to 150 bars. The fuel pressure induced into common rail is reduced up to 172.5 bars by a pressure limiting valve. The injectors are sequential solenoid-controlled six-hole fuel injectors, mounted on the intake side between the intake port and cylinder head gasket level. The injection system for this engine test is actually used in commercial engine production. Therefore no specific support from the injector manufacturer is needed. VW has confirmed that this engine will be available for at least ten years. The lead lab for the test development will be required to pay VW AG for any EA111 engine(s) needed in the test development phase. VW will help with the installation of the engine(s) in the lead lab. Furthermore, VW fuel and engine engineering specialists will provide technical support on the hardware, lubricant and fuel requirements of this engine during the development and implementation phases, including advice on reference fuels and oils. It is intended that advice will be given on setting up and running the engine on test benches, and that sealed engine control units will be made available to laboratories interested in installing the engine for this test. 3. Test Procedure 2016/9/15 Final Version Page 4 of 7
It is recognized that this test development will need an investigation phase to define a practical and acceptable test. The following guidance is given and should be discussed and investigated during test development: General considerations: For the evaluation of the performance of a DCA it is required to develop a procedure to generate on one hand deposits with a high focus on reproducibility and on the other hand is able to discriminate between fuels. The procedure should be designed to address both keep clean and clean-up performances For cleanup testing the proposed test cycle should be used; for keep clean operations another test cycle might be developed. However, one test cycle to address both is preferable.. Develop a procedure which is optimized for both time and cost efficiency. Define the way to clean and reuse the injector set without affecting test precision. Define appropriate project timing for each stage of the development and frequency of reporting progress. The procedure to generate deposits developed by VW is not complicated and the duration is manageable. The measured variable for this test is the injection time (duration). Another measured variable is the air fuel ratio. It operates as termination condition for the test run. If the air fuel ratio runs out of operating range, the test is failed. The basic (keep clean or dirty up phase) test run consists of 48 hours deposit formation with a continuous measurement of the increase of injection time. The clean-up procedure will start with a dirty up phase of 48 h (see above) followed with additized fuel for 24 hours. Ideally the injection time reaches the initial value of the test run. An example with the complete procedure is shown in Figure 1. Dirty up phase: fuel w/o additive Clean up phase: fuel w/ additive Figure 1: Example of DISI injector fouling 2016/9/15 Final Version Page 5 of 7
A particular requirement exists for the injector nozzle. Each set of Injectors need to have a similar injection behavior. In addition all injectors have to pass a leakage test. The test procedure shall be defined during test development. Additional parameter such a visual inspection of spark plug fouling can be included but will not be considered as a limit setting criteria. 4. Reference Fluids The TDG will select the reference fuels either from existing CEC reference fuels or if required develop new reference fuels that will achieve: - Reproducible injector deposits formation (dirty up phase) defined as Low Reference Fuel - Discrimination between high and low injector deposits formation for both keep clean and clean up protocols, defined as Low and High Reference Fuels The reference fuels shall be, preferably, in accordance with EN 228 latest edition. For the running-in process, a fuel with low deposits formation tendency is recommended. This fuel can be the same as the High Reference Fuel. Reference lubricant: the TDG will select the reference lubricant that meets VW requirements for this engine. 5. CEC Management Board Approval Following CEC Management Board approval of the Template and Terms of Reference the lead development laboratory will be selected through the CEC tender process. A request for sponsors will also be made using the usual CEC defined process. Consideration should be given by the TDG as to whether a tender process is required to select a reference fuel(s) supplier and/or a reference oil supplier. The TDG must submit data showing the test repeatability before clearance is given by the CEC Management Board to progress the test development to phase 2, which is the installation of the test at additional test laboratories. 6. Proposed timeline - 09/ 2016: o CEC MB finalization and approval of terms of reference o Information published on CEC website and start of tendering process according to CEC Guidelines 10-10/2016 o Organization pre-tender meeting - 11-12/2016 o End of tender and selection of lead lab o Call for sponsors o Selection of TDG Chair - 1/2017 o Installment of TDG and start of work according to CEC Guidelines 11 o Start Phase 1-12/2017 o End Phase 1 and approval from CEC Board - 1/2018 o Start Phase 2-9/2018 o End phase 2 and approval from CEC Board 2016/9/15 Final Version Page 6 of 7
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