Cylinder leak detection using the cylinder leak detector.The basic principle of the test is to use the compressed air filled into the cylinder, with a pressure gauge to detect the piston at the end of the compression at the end of the cylinder when the Yanhua DR-Key adapter pressure changes, to characterize the entire cylinder group of OBD2 sealing.That is, not only the seal of the piston piston friction, but also to characterize the intake and exhaust valve, cylinder liner, cylinder head and cylinder seal.
(1) cylinder leak detector structure and working principleDomestic QLY-1 type cylinder leak detection Diagspeed MB Key device mainly by the pressure reducing valve, intake pressure gauge, measuring table, calibration orifice, rubber hose, quick change pipe fittings and inflatable mouth and other components, as shown in Figure 2-12 The In addition, there must be an external air supply, a pointer to the piston position and a piston positioning plate.The pressure of the external air supply should be equivalent to the cylinder compression pressure, generally should be 600 ~ 900kPa. Compressed air according to the direction of the arrow into the cylinder leak detector, the pressure from the intake pressure gauge display.
WithAfter which it enters the cylinder at the end of the compression end through the pressure reducing valve，Fcar FVCI Passthru tool the calibration orifice plate, the rubber hose, the quick change pipe fitting, and the inflatable nozzle. The pressure change in the cylinder is shown by the gauge. The pressure changesThe condition indicates the seal of the cylinder block.Cylinder Leakage Diagnostic Parameter StandardFor the cylinder leak, China has not developed a unified diagnostic parameters. Auto Repair
QLY-1 Cylinder Air Leakage Detector In the instruction manual, for the engine of the domestic truck, when the inlet, the exhaust valve and the cylinder liner are well sealed, the cylinder seal condition (mainly refers to the cylinder piston) Judgments can be dealt with in Table 2-6. When the meter reading is greater than 250kPa,Cylinder piston with sub-sealing conditions meet the requirements, the engine can continue to use; when the meter reading is less than 250kPa, the cylinder plug with the deputy seal does not meet the requirements of the engine cylinder to be ring or boring cylinder. Transportation industry standard JT / T201-1995 "vehicle maintenance process specifications" in the vehicle before the second maintenance of the use of the reference diagnostic parameters of the standard requirements of domestic Dongfeng EQ1090 and the liberation of CA1091 car cylinder leak, When the cylinder piston is placed in the static compression top dead center position, the measured gauge pressure should be ≥ 250kPa.