Cylinder sealing and pressure detection

Cylinder seal and cylinder block, cylinder head, cylinder pad, piston, piston rings and into the technical conditions of the exhaust valve and so on parts. In engine in use process, because these parts wear, ablation, coking and carbon deposition, resulting in a decline in cylinder sealing and bring down the engine power, fuel consumption increase, shorten service life. Cylinder sealing is one of the important parameters represent engine technical status. Under the condition of without disassembly, detection of cylinder sealing of the commonly used methods are: measuring cylinder compression pressure. Measure the crankcase leap into gas; Measuring cylinder air leakage or cylinder gas leakage rate; Measuring the intake pipe pressure, etc. On vehicle detection, with one or two of them, can determine the stand or fall of cylinder sealing. A cylinder compression pressure testing, testing the check point on the end of the piston to compress the cylinder compression pressure can show the size of the cylinder seal. Detection methods, using cylinder pressure gauges to detect and cylinder pressure tester for testing. Cylinder pressure gauge is used to inspect due to cylinder pressure gauge is used to inspect the cylinder compression pressure ( Hereinafter referred to as the cylinder pressure) With low cost, convenient instrument is light, strong practicability and detection, and therefore they are widely used in automobile repair enterprises. ( ) Engine running test method, the water temperature reaches ℃ above. After downtime, remove the air filter, with compressed air blowing off the dust and dirt around the spark plug or fuel injector, then remove all the spark plug or fuel injector, and placed in a cylinder sequence. For gasoline engine, but also the distributor of the central electrode under the high tension line drawing and reliable iron, in order to prevent electric shock and fire, and then insert a rubber joint of cylinder pressure gauge in the spark plug hole of the measured cylinder, centralizer pressure. Throttle and choke valve in full open position, with the starter cranking ~ s ( No fewer than four compression stroke) With pressure meter pointer stop running after the maximum stress and maintain. Remove the cylinder pressure gauge, write down the readings, press the check valve pressure gauge pointer back to zero. According to the above method in measuring each cylinder, each cylinder measurement times no less than two times. Should be used on car testing diesel engine cylinder pressure, cylinder pressure gauge of nipple. If the machine requirements under the high speed measurement, the situation in addition to the tested cylinder, the cylinder should be work. Other same as gasoline engine test conditions and test methods. ( ) Diagnostic parameters standard cylinder compression pressure normal value provided by the manufacturer. According to GB/T. The car repair, quality inspection evaluation standard engine overhaul, the regulation of appendix B: overhaul completion of engine cylinder pressure should comply with the regulations of the original design, each cylinder pressure and average each cylinder pressure difference, no more than % of the gasoline engine, diesel engine is no more than %.