Dynamometer HA061-2 Handout Activity: HA061 Dynamometer The dynamometer applies various loads on the engine and measures the engine s ability to move the load. There are two types of dynamometer: Engine dynamometer and Chassis dynamometer. A dynamometer is a machine that measures the torque and power produced by an engine. It applies various loads to an engine and is usually connected to a computer that can analyze and calculate all the aspects of engine operation measured. Dynamometers are particularly useful in designing and refining engine technology. They can help identify how an engine or its drive train need to be modified or tuned to achieve more efficient power transfer. There are two types of dynamometer: Engine Dynamometer: This type measures engine performance only and usually when the engine is removed from the vehicle and mounted onto a special frame. It is coupled directly to the engine flywheel and measures performance independent of the vehicle s drive train such as its gearbox, transmission, or differential. Chassis Dynamometer: This type measures the power from the engine through a vehicle s driven wheels. The whole vehicle is mounted on rollers and fixed to the ground to prevent it jumping when it is driven during testing. The vehicle is driven in gear and turns the rollers without moving, while its power output is measured. 1. An engine dynamometer measures power and torque directly from the engine s (or flywheel), when the engine is removed from the vehicle. 2. This type is normally fixed in a special that allows engines to be mounted on to it and can be directly coupled to the engine flywheel. 3. Modern dynamometers are normally connected to a which uses math to calculate the output of the engine. 4. A chassis dynamometer measures power from the engine through the. Score / 4 20070903 Page 1
Pressure testers HA062-2 Handout Activity: HA062 Pressure testers There are a range of pressure testers used in the automotive industry. Each of them are used to provide information about the potential condition of various systems and components There are a range of pressure testers used in the automotive industry. Each of them is used to provide information about the potential condition of various systems and components. All gauges consist of a measurement scale from which a reading is taken. Depending on the type of fitting on the gauge, it is normally fitted to the vehicle component via a pipe or tube. Instructions provided with the gauge will describe how to take a correct reading. These should include the specific operational circumstances that the reading should be taken under, in order to interpret correctly the condition of the item being tested. Most gauges are designed to read zero at atmospheric pressure (14.7lbs/sq inch or 1 Bar at sea level) as a base measurement. Some types and applications: Tire pressure gauges 1: This type of gauge is the one most familiar to most people. Tire pressure gauges are normally part of a tire inflation device and are used to ensure that the air pressure inside the vehicle tires is maintained at the recommended setting. Tire pressure gauges 2: Gauges that only measure, that is, they just check the pressure without being able to inflate as well, are also quite common. The illustration on the left is an example of this type, known as a pencil-type pressure gauge. 20070905 Page 1
Pressure testers HA062-2 Vacuum gauges: These gauges are a particular type pressure gauge that measures negative pressure below atmospheric pressure. They are normally used to determine an engine s general operational condition. Depending on the reading a number of engine faults can be identified. Compression gauges: These gauges are used to measure the compression pressures inside an engine cylinder and can identify overall condition and pressure leakage situations that could be caused by a range of engine faults. Cooling system pressure gauges: These are used to identify faults in cooling systems and components like pressure caps. 20070905 Page 2
Pressure testers HA062-2 1. These gauges are used to measure the compression pressures inside an engine and can identify over all condition and pressure leakage situations that could be caused by a range of engine faults. 2. These gauges are not regarded by many as a pressure gauge, but in fact they are because the measure pressure below atmospheric pressure. 3. Each of them are used to provide information about the potential of various systems and components.. Score / 3 20070905 Page
Scan tools HA063-2 Handout Activity: HA063 Scan tools Scan tools are used to run diagnostic tests on vehicles to obtain information on the probable cause of faults. They are able to communicated with the on-board control computer fitted in a vehicle. A scan tool is a device that is able to communicate with the on board control computer fitted in a vehicle. The scan tool is a software driven device that contains information about the particular vehicle it is fitted to and communicates with the various on board systems to determine their status and condition. A scan tool can be a standalone battery operated piece of specialized equipment, or it can be a device that links the onboard computer system to a PC running on board diagnostic software. The automotive industry introduced on board diagnostics standards OBD1 and OBD2. The original OBD1 specification did not have a standard link connector, nor a standard data protocol, so the early on board diagnostic systems were highly proprietary to each manufacturer. The OBD2 specification standardized the connectors and the test signaling protocols, and also specified a common but extensible set of Diagnostic Trouble Codes (DTCs). OBD2 started to become mandatory for all vehicles in 1996. The scan tool connector is usually located in the front of the passenger compartment on the driver s side, so that the technician can operate the scan tool and see any Malfunction Indicator Lights (MIL) that may be on the instrument panel at the same time. The scan tool displays the Diagnostic Trouble Codes that have been stored by the vehicle s control system, and it can also carry out some diagnostic tests on vehicle systems. The intention is to provide the technician with enough diagnostic information to be able to identify and rectify faults. When the faults have been rectified, the scan tool can also reset or clear the DTCs. 20070905 Page 1
Scan tools HA063-2 1. OBD2 started to become for all vehicles in 1996. 2. The intention is to provide the technician with enough information to be able to identify and rectify faults. 3. The original OBD1 specification did not have a standard link connector, nor a standard data protocol, so the early on board diagnostic systems were highly proprietary to each. 4. A scan tool is a device that is able to with the on board control computer fitted in a vehicle. Score / 4 20070905 Page 2
Multimeters (DVOM) HA064-2 Handout Activity: HA064 Multimeters (DVOM) Multimeters are electrical test tools and are used to diagnose problems in vehicle electrical systems, however their use has been reduced with the advent of on-board diagnostics and the use of scan tools. Digital Multimeters (DMM) or Digital Volt Ohm Meters (DVOM) as they are also commonly known are very widely used in the automotive industry, and are the most generally useful testing tools. In the hands of a qualified operator the DVOM can be used to diagnose very complex problems in vehicle electrical systems, however some of this testing work has been shortened or eliminated with the introduction of on-board diagnostics and the use of scan tools. There are several types of DVOM available at different price points. The more substantial and usually more expensive types have more functions and are generally more reliable. In some locations many meters are known more commonly by their brand name. Description The DVOM is an electronic measuring instrument that combines several functions in one unit. The most basic instruments include an ammeter, voltmeter, and ohmmeter. The meter usually has a central rotating selection switch which is used to select the electrical test function that the meter is going to be used for, and a set of input points that are used to connect the meter to the item/circuit being tested by test leads. Most meters also have a safety fuse fitted (of about 10 amps maximum) for operational safety and to prevent damage to the meter should it be connected to excessive electrical loads. Some additional features available in some multimeter units: A continuity tester that makes an audible sound when a circuit is not broken, or shorted. Digital numerical output of the quantity under test. An amplifier to sense small voltages, currents and high resistances. Measurements of inductance and capacitance. Tests of diodes and transistors. Scales and sockets for temperature measurement with standard thermocouples. An intermediate-frequency oscillator, a detector and an audio amplifier with a speaker, to diagnose and tune radio circuits. A slow oscilloscope. This is available mainly in high-end computer-controlled multimeters. 20070905 Page 1
Multimeters (DVOM) HA064-2 1. The meter usually has a central selection switch which is used to select the electrical test function that the meter is going to be used for, and a set of input points that are used to connect the meter to the item/circuit being tested by test leads. 2. An amplifier to sense small voltages, currents and high. 3. The DVOM is an electronic measuring instrument that combines several functions in one unit. The most basic instruments include an ammeter, voltmeter, and. 4. A tester that makes an audible sound when a circuit is not broken, or shorted. 5. Tests of diodes and. Score / 5 20070905 Page 2
Test light HA065-2 Handout Activity: HA065 Test light A test light is a tool for testing circuits. It usually has a light that indicates the presence of an electrical current in the circuit to which it is attached. A test light is a basic circuit testing tool. It consists of a mobile probe with a small lamp or light bulb attached, connected via an insulated wire or cable to a small clip that can be clamped to a suitable return point for completing the circuit. When each end of the tester is connected to a circuit carrying a voltage, then the lamp will light up. The metal probe is usually sharp enough to penetrate cable insulation so that the tester can connect directly with the conducting wire inside. 1. It is normally constructed in such a way that the tester is from the user and has a small bulb in the circuit. 2. One end of the tester has a probe that is able to pierce the insulation of cables and the other end has a small clip that is able to be clamped to a suitable return point for of the circuit. 3. A test light is normally used as a basic testing tool to ensure that the circuit is carrying a voltage to enable an electrical component to operate. Score / 4 20070903 Page 1
Hydrometer HA066-2 Handout Activity: HA066 Hydrometer A hydrometer is an instrument used for determining the specific gravity of liquids. Common applications of a hydrometer are in battery testing for state of charge and coolant testing for coolant concentrate to water ratio. An hydrometer is an instrument that measures the specific gravity of fluids. Specific gravity means the relative density of the fluid in comparison to the density of water. The hydrometer is usually made of glass and it consists of a chamber to contain some of the fluid to be measured and a calibrated float. If the mass of any object is greater than its equivalent volume of fluid, then it will not float in the fluid, but will sink. For instance, a steel ball is heavier than an equivalent-sized ball of water, so it will not float in water. By contrast, if the mass of an object is less than the equivalent volume of fluid, it will float. For instance, a table tennis ball is much lighter than a table tennis ball-sized volume of water, so it will float in water. The floating force acting on the object is always equal to the weight of the fluid being displaced by the mass of the object. Therefore, if the fluid was a very heavy fluid, it is possible that the steel ball could float, and if the fluid was an extremely light fluid, it is possible that a ping-pong ball would not float, but instead would sink. In the hydrometer, the float will ride higher or lower in the water depending on the density of the fluid it is floating in. The calibrations on the float at the fluid level indicate the specific gravity of the fluid. In the automotive industry, hydrometers are used to measure the specific gravity of fluids such as battery electrolyte to assess the acid concentration; radiator coolant to assess the freeze point, and diesel fuel to determine the Cetane level. 20070905 Page 1
Hydrometer HA066-2 1. In each case the hydrometer is different because it has a particular on the float to suit the particular application. 2. Hydrometers usually contain a scale inside the stem, so that the specific gravity (or density) can be read directly in grams per cubic centimeter. 3. The function of the hydrometer is based on Archimedes principle that a solid suspended in a liquid will be buoyed up by a force equal to the of the liquid displaced. 4. A hydrometer is an instrument used for determining the specific of liquids. Score / 4 20070905 Page 2