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The malfunction caused by the ECU of the electronic control engine computer

The malfunction caused by the ECU of the electronic control engine computer

The electronic control engine computer ECU cannot monitor the failures caused by the following reasons. (1) Generally, the ECU of low-end cars cannot monitor the failure of the high-voltage ignition circuit caused by the inoperative ignition coil, the polluted or damaged spark plug, and the broken core of the high-voltage line. (2) ECU cannot monitor the blockage of the inlet filter of the electric gasoline pump, the fuel filter pipeline, and the failure of the incoming fuel caused by the flattening of the fuel inlet pipeline or the return pipeline. Smooth, or the mixture is too thin. Loose rearview mirror in Mercedes-Benz car (3) The ECU cannot monitor the air filter inlet or the air filter plugging or throttling. The solution to the failure or vibration caused by the change of the air flow rate. Product brand summary Commonly used accessories for Mercedes-Benz maintenance and repair (4) ECU cannot monitor the high or low cylinder pressure, or the uniformity of each cylinder pressure (5) ECU cannot monitor the plug and the pins are damaged, but it will produce fault codes caused by this situation (6) ECU cannot monitor the bad grounding, but it will produce fault codes caused by this situation (7) ECU cannot monitor the leakage or throttling of the vacuum line of the vacuum booster in the engine control system. However, the vacuum degree of the absolute pressure sensor of the intake manifold will be monitored and the ECU will also record the fault code. The above 10 items are the causes of failures that cannot be detected by the electronic control engine, which should be paid attention to when repairing the electronic control engine. Whether it is an electronic control failure or a mechanical failure, the location and performance characteristics of the occurrence must be correctly distinguished in order to accurately and quickly determine and eliminate the failure During the inspection, if the engine is faulty and the engine fault warning light is not lit (the fault code is not displayed), it means that the engine fault may be in the mechanical part.

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Function and composition of engine block group

Function and composition of engine block group

Body group function The body group is the support of the engine, and is the assembly base of the crank connecting rod mechanism, the valve mechanism and the main components of the engine systems. The cylinder head is used to close the top of the cylinder and form a combustion chamber together with the top of the piston and the cylinder wall. In addition, the water jacket, oil passage and oil pan in the cylinder head and body are the components of the cooling system and lubrication system respectively. Body group composition structure Modern automobile engine block group is mainly composed of block, cylinder head, cylinder head cover, cylinder liner, main bearing cover and oil pan. For engines with cylinder liners, the body group also includes dry or wet cylinder liners.

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Engine start-stop technology

Engine start-stop technology

As the name implies, the engine start-stop system is to automatically turn off the engine when the vehicle is temporarily stopped (for example, waiting for a red light) while the vehicle is running. When it is necessary to move on, the system automatically restarts a set of systems of the engine. For models equipped with automatic transmissions, the automatic start-stop system works as follows: As long as you directly step on the brake pedal while driving, the engine will automatically turn off after about two seconds after the vehicle is completely stopped. If you keep stepping on the brake pedal, the engine will remain off. As soon as the brake is released or the steering wheel is turned, the engine will automatically ignite again, and the accelerator can be started immediately again, and the whole process is in the D gear state. In order to solve the problem of being too tired from stepping on the brake, as long as the AUTOHOLD electronic handbrake is also turned on, the engine will only be lightly stepped on the accelerator in the Mercedes-Benz car) After starting the board, the right foot does not need to be kept on the brake. Or vibrating The engine start-stop system is the most rapidly developed automotive environmental technology in recent years, especially suitable for stop-and-go urban road conditions. It is estimated that by 2012, 50% of newly launched cars in Europe will be equipped with a start-stop system. According to reports, this system can achieve 15% fuel-saving capacity under urban conditions. The working principle of engine start-stop technology The working principle of the start-stop system is when the vehicle stops due to congestion or intersection. The driver depresses the brake pedal, stops and picks up gear. At this time, the Start/St op system automatically detects: the engine is idling and not in gear: the wheel speed sensor of the anti-locking system shows zero; the electronic battery sensor shows that there is enough energy for the next start. After these three conditions are met, the engine automatically stops rotating. When the signal light turns green, the driver steps on the off-stage device, and then can start the "start stopper" and quickly start the engine. The driver engages in gear and steps on the accelerator, and the vehicle starts quickly. With the support of high-efficiency battery technology and corresponding engine management procedures, the start-stop system can also work normally at lower temperatures, and can be activated after a short warm-up process. Instructions: As long as you directly step on the brake pedal while driving, the engine will automatically turn off after about two seconds after the vehicle is completely stopped. If you keep stepping on the brake pedal, the engine will remain off. As soon as the brake is released or the steering wheel is turned, the engine will automatically ignite again, and the accelerator can be started immediately again, and the whole process is in the D gear state.

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Engine power evaluation index

Engine power evaluation index

Engine power evaluation indicators include: engine effective power (shaft power, rated power, standard power) and engine effective torque, calibrated speed, etc. are all evaluation indicators of engine power. Limit planting: The power of the vehicle in use cannot be lower than 75% of the rated power, and it cannot be lower than 90% after overhaul.

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How to judge and calculate the pressure difference of each cylinder of the engine

How to judge and calculate the pressure difference of each cylinder of the engine

Technical standards for gas pressure: CA6102: 934KPaEQ6100 is not less than 834KPa, the use limit is 670KPa The fourth cylinder does not meet the conditions, you should check and calculate the average of the two measurements of each cylinder: then calculate the average pressure of the six cylinders. Calculate whether the pressure difference of each cylinder exceeds 6% of the average The maximum value of the average value is: 802.5x(1+5%)=842.625Kp8 The minimum value of the average value is: 8025x(1-5%)=762.375Kpa If the measured average value is between (762.375-842625) Kpa, it meets the requirements. The fourth cylinder is less than the average value and should be checked. Measuring cylinder pressure is a simple and scientific method of diagnosing engine failures. The correct use of the method of measuring cylinder pressure can accurately and quickly diagnose some common engine failures, especially those drivers and repairers should master. The car should start smoothly when the ambient temperature is not lower than -5℃, and it is allowed to start no more than 3 times, and each start should not be more than 5s. Check that more than three starts or more than 5s are unqualified. Hot car starts on the engine. Under normal operating temperature, it can be started within 5 seconds. If it does not meet the requirements, the vacuum degree is unqualified. When the gasoline engine is idling, the vacuum degree of the intake manifold should be within the range of 57-70kPa. (The plane shall prevail) Failure to meet the requirements is the unqualified vacuum fluctuation range. When the engine is on, the intake manifold vacuum fluctuates The six-cylinder gasoline engine does not exceed 3kPa, and the Sijiang gasoline engine does not exceed 5kPa. Use a tachometer and vacuum gauge to check the atmospheric pressure based on sea level. Standard) Failure to meet the requirements is the unqualified cylinder pressure value. Cylinder compression pressure should meet the original design regulations. Use a tachometer. Cylinder pressure gauge inspection does not meet the requirements. The pressure difference of each cylinder is the difference between the pressure of each cylinder and the average pressure of each cylinder. Not exceed 89, diesel engine not more than 10% using tachometer, cylinder pressure gauge or engine comprehensive analyzer to measure failure to meet the requirements as unqualified

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