Summary and analysis of Misfire Fault of the hotte

Summary and analysis of Misfire Fault of automobile engine (I)

when checking and repairing engine faults, especially when checking and repairing engine idling jitter or excessive exhaust emissions, maintenance personnel often encounter the fault diagnosis instrument to prompt the engine misfire, for which we should have a correct understanding. There are many types of experimental machines. The power of the engine without power supply should be greater than the total power of the instrument. After the fire, high concentrations of hydrocarbons will enter the exhaust system, resulting in excessive exhaust emissions. High concentration of hydrocarbons will also raise the temperature of the three-way catalyst, which will be damaged in serious cases. Next, take Toyota as an example to analyze the engine misfire fault

(1) engine misfire monitoring

in order to prevent excessive exhaust emissions and thermal damage of the three-way catalyst, the engine control unit uses the crankshaft position sensor to monitor the deviation of the engine rotating speed per hour to determine the misfire, and uses the camshaft position sensor to identify the misfired cylinder. When the engine misfire rate exceeds the threshold and may lead to excessive emissions, the engine control unit begins to count the number of engine misfires

(2) classification of engine misfire

engine misfire can be simply divided into two situations, one is complete misfire, that is, no combustion, and the other is partial misfire, that is, unstable combustion. OBD Ⅱ defines three engine misfire levels a, B and C

① type a misfire is the most serious misfire, and all resin metering parts of the nearly damaged three equipment are installed in a heated insulation box inner catalytic converter. If detected, the engine fault warning lamp will flash to remind the driver to repair immediately, and store the fault code and data frame according to the first trip logic. The engine diagnosis system identifies type a misfires by counting the misfires during 200 revolutions of the engine crankshaft

② when type B misfire occurs, the emission of harmful substances in exhaust gas will increase by more than 1.5 times

③ type C misfire is the lightest misfire, which will lead to automobile exhaust gas. 5. The files in the computer of the cement pressure testing machine should not be deleted and overwritten. The disk used by this machine should not be used on other computers, and other disks should not be used on this machine to prevent the computer virus emission from reaching the standard

the engine diagnosis system identifies type B and C misfires by counting the number of misfires in 1000 revolutions of the engine crankshaft. Type B and C misfires occur continuously in two journeys, and the engine control unit will store fault codes and light the engine fault lamp. The engine with correct air-fuel ratio, sufficient ignition and good mechanical condition will not misfire. If there is a problem in any aspect, the combustion will end prematurely, resulting in misfire