2022-11-17
How to analyze the results of engine cylinder sealing test.
The main factors affecting the sealing performance of the cylinder are cylinder wear, piston ring damage, piston wear, valve seat damage, valve guide wear, cylinder seal damage, valve clearance, etc.
What is the usual diagnostic method? Vibration measurement mainly includes cylinder pressure, crankcase flushing, cylinder leakage and leakage rate, intake pipe vacuum and abnormal noise caused by excessive wear of cylinder piston group. The wear metal in the crankcase is a measurement of the particle content.
For the measurement of cylinder pressure, it is mainly the pressure at the end of four stroke engine compression. Because of factors such as cylinder pressure and oil viscosity, compatibility of cylinder piston group, correct adjustment of valve distribution mechanism and sealing performance of cylinder seals, it is possible to diagnose whether the cylinder piston group is sealed when measuring engine cylinder pressure. If the piston rings, valves and cylinder seals are well sealed, the valve spacing must be sufficient.
Before removing the spark plug, we mainly use compressed air to clean the dust around the spark plug. For gasoline, we should disconnect the secondary high-voltage line of the ignition system and make it firmly grounded. This is to prevent electric shock and fire. Insert the conical rubber plug of the special cylinder pressure gauge into the spark plug hole measured in the cylinder. The spark plug hole must be straight and tightened. For special throttling valves, they must be fully opened. The starter must drive the corresponding rotation of the crankshaft. If the pointer of the pressure gauge remains unchanged to some extent, the rotation must be stopped after the worst pressure reading. Finally, remove the pressure gauge and record the measured value.
The National People's Congress and its annual session opened. The two meetings in 2011 only summarized the key points of the 11th Five Year Plan and predicted the 12th Five Year Plan. Therefore, there will be a lot of discussion on how to become bigger and stronger in the automotive industry at the two meetings in 2011.
The theme of the "Twelfth Five Year Plan" for the automotive industry is "to become bigger and stronger". The core of strengthening is core technology, core competitiveness and independent innovation. For some time, the independent innovation of finished vehicles has made some progress, and the existing foreign platforms can be used to develop new products, but the platform development is still weak. The independent innovation of auto parts has been ignored, and the auto parts industry with its own brand has been in a marginal position for a long time. As the automobile parts manufacturers may not be highly representative in the two national congresses, they have not understood this problem for many years.
The Ministry of Commerce said that foreign capital controls most of the market share of auto parts. The revenue of domestic spare parts only accounted for 20.25% of the whole industry. Foreign auto parts manufacturers account for more than 75% of the whole industry. Among these foreign suppliers, 55% are wholly owned enterprises and 45% are Sino foreign joint ventures. Local parts are mainly used for private brand vehicles with small market shares.
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