What are the requirements for the installation of car engine
The piston ring of the engine works under high temperature, high pressure and high-speed reciprocating motion of the piston, so the piston ring must have wear resistance, corrosion resistance, heat resistance, and strong rigidity and elasticity. The current steel piston ring replaces the previous cast iron piston ring. For the high-power diesel engine, the piston ring material is generally made of gray cast iron, nodular cast iron, alloy cast iron and vermicular cast iron. There are two types of piston rings for an engine, one is an air ring and the other is an air ring. The role of the piston ring: 1. Has good air tightness: the combustion gas in the main sealed cylinder leaks to the crankcase, which is usually called the 'blow-by gas' phenomenon, and the gas leakage is controlled within a controllable minimum, thereby improving the thermal efficiency. 2. Has good thermal conductivity: It must be able to transfer the high temperature and heat generated by the combustion to the cylinder wall through the piston ring to play the role of cooling the piston. Generally, the heat of the cargo is also emitted to the cylinder wall, which is 30% to 40% of the heat received by the top of the piston. 3. It has the function of supporting the piston. Since the diameter of the piston is slightly smaller than the inner diameter of the cylinder, if there is no piston ring, the piston will contact the friction with the inner wall of the cylinder when moving up and down, causing the instability of the piston when moving up and down in the cylinder. The elasticity of the piston supports the movement of the piston without contacting the cylinder wall, but it slides against the cylinder wall by the outer surface of the piston ring. 4. Must have good oil tightness (the role of the oil ring): the engine oil that can seal the crankcase enters the cylinder and scrapes off the excess lubricating oil on the cylinder wall. At the same time, there is a thin layer on the cylinder wall The oil film ensures the normal lubrication of the cylinder, piston and piston ring. Engine piston ring installation requirements 1. Put the piston ring flat into the cylinder liner, and push it gently with the piston. Check that there is a certain opening gap at the piston ring interface. If the gap is too small, the cylinder wall will be damaged due to thermal expansion. If the gap is too large, it will affect the tightness. The end gap should be between 0.2 and 0.5 mm. The Swiss gap is different due to different materials and regulations. 2. The piston ring should be installed in the ring groove of the piston. The side of the piston ring has an upward arrow or 'TOP' logo, which is installed face up. If it is reversed, the oil will burn. 3. The chromium ring should be installed in the first lane, and the opening should not face the direction of the vortex pit on the top of the piston. 4. The opening of each piston ring should be at least 120 ° offset from each other, and it is not allowed to face the piston pin hole. 5. When installing the torsion ring, the chamfer or notch should be upward. When the conical section piston ring and the conical surface reverse torsion ring are installed, the conical surface is kept upward. 6. When installing the combination ring, the axial backing ring should be installed first, followed by the flat ring and the wave ring. A flat ring is installed above and below the wave ring, and the openings of the rings should be staggered from each other.