First, the engine cylinder tightness test
There are seven factors that affect the tightness of the cylinder, mainly including the wear of the cylinder, the damage of the piston ring, the wear of the piston, the damage of the valve seat, the wear of the valve guide, the damage of the cylinder pad, and the valve clearance.
What are the commonly used diagnostic methods? It mainly measures the vibration measurement of cylinder pressure, crankcase blow-by gas, cylinder leakage and leakage rate, intake pipe vacuum degree, abnormal noise caused by excessive wear of cylinder piston group, and the wear metal in crankcase is particle content. Determination.
For the measurement of cylinder compression pressure, it is mainly the pressure at the end of compression of a four-stroke engine. Due to factors such as the pressure of the cylinder and the viscosity of the oil and the cylinder piston group, whether the adjustment of the valve train is correct, the tightness of the cylinder gasket, and other factors, so when measuring the pressure of the engine cylinder, the cylinder piston group can be diagnosed If the sealing of the piston ring, valve and cylinder gasket is good, the clearance of the valve must be proper.
Second, the muffler firmness test
The muffler is composed of an outer cylinder and an inner honeycomb part. The two parts are combined by a mechanical buckle process due to the special environment such as high temperature and vibration. We know that the quality of this process depends on the precision of the design. If it is not firmly combined, it will loosen or fall off due to high temperature, vibration and other factors in the use of the car. But let us rest assured that the relevant quality first department has put forward quite strict requirements on this technology.
For the actual testing method industry, the testing tools are all-purpose material testing machines, and the pressure-resistant disc fixture is used to subject the two components of the muffler to the relevant shear forces. The repeat error of the measured results should be less than 5%.
Third, interior testing
The interior includes seat-forming materials, interior trim materials, and adhesives for bonding. Mainly test its safety: 1. Gas harmfulness 2. Flame retardant.