Lubrication methods of automobile engines can be classified into four basic types: pressure cycle lubrication, splash lubrication, oil mist lubrication and grease lubrication. According to different lubrication parts, these four lubrication methods all play an effective role according to their own characteristics.
Pressure circulation lubrication
For the lubrication of friction surfaces bearing heavy load, such as main bearing, connecting rod bearing, camshaft bearing, valve rocker mechanism, etc., lubricating oil is injected into the friction surfaces with a certain pressure by using a lubricating oil pump, which is called pressure circulation lubrication. It is characterized by reliable operation, good lubrication effect and good cleaning and cooling effect, but the system structure is more complicated.
Grease lubrication
For the parts of other auxiliary mechanisms, such as fan, water pump shaft and engine shaft, due to the small load and little friction loss, grease is regularly added for lubrication.
Oil mist lubrication
For the lubrication of friction parts with less load or relatively low movement speed, such as the ball head of the valve adjusting screw, the top end of the valve rod and the rocker arm, oil mist is used to adhere around the friction surface, and then slowly converge and penetrate into the friction parts. This way is oil mist lubrication.
Splash lubrication
For the lubrication of friction parts that are difficult to reach or bear little load by pressure oil delivery, such as cylinder wall, timing gear, cam surface, etc., the splashing or falling action of moving parts is used to deliver lubricating oil to the friction surface, which is called splash lubrication. It is characterized by simple structure and low power consumption, but the lubrication reliability is low, which is easy to cause oxidation and pollution of lubricating oil.