Introduction to the cylinder pressure detection technique

Cylinder is in use process, due to wear and ablation, sticking, carbon deposition and other reasons, the cylinder piston group of technical conditions deteriorate, which makes the cylinder sealing, engine performance and fuel economy decline. Cylinder compression pressure detection is check the sealing quality of piston rings, valve and combustion chamber. Engine cylinder pressure is too low, will cause the engine power decline, fuel or oil consumption increase, the emission levels of start-up difficulties. Engine cylinder pressure is too high, will cause the engine detonation, start the difficulties. Each cylinder uneven pressure of engine, will cause the engine running rough, or lack of cylinder. This failure occurs for engine cylinder pressure detection. Through the analysis of the engine cylinder pressure detection, diagnosis of engine cylinder sealing and inlet and exhaust system is unobstructed, supplemented by other detection and analysis to find out the fault point, to determine which aspects need to repair. Cylinder pressure check method first look at the engine working conditions of engine cylinder pressure. Most of efi engine cylinder pressure in kPa ~, a high compression ratio of engine cylinder pressure above the kPa. Original design engine cylinder pressure mainly depends on the size of the volume of the combustion chamber and the engine compression ratio, and is there a pressurization mechanism; Actual use of the main factors influencing the engine cylinder pressure have how much carbon deposition in the combustion chamber, and the sealing condition of the combustion chamber and exhaust is obstructed, etc. Attention, checking cylinder compression pressure ( ) Cannot be measured cylinder pressure when cool car, due to the influence of factors such as temperature and atmospheric pressure, only when the engine to normal operating temperature measured cylinder pressure, is the substantial reference value. ( ) For efi engine in the test have to remove the fuel pump insurance or other relay measurement again, otherwise often lead to 'submerged cylinder and the cylinder pressure is low. ( ) Testing, throttle choke valve must be opened entirely, otherwise the shortage of the combustion chamber into the gas in cylinder pressure is low. ( ) Due to cylinder pressure measurement has certain chanciness, measuring only one often inaccurate, only through to the test, and then take the average test result is valid and reliable. ( ) Test the starter operation time is not too long or too short. Time is too long will consume too much power and damage to the starter, it can not meet the test standard are too short.