Study On The Friction Power Of Diesel Engine By Loading High Pressure Gas On The Cylinder Rings

Friction loss in diesel engine is caused by mechanical friction, fluid resistance and driving auxiliary apparatus. Friction loss caused by cylinder liner-piston rings and crank shaft almost takes up 60% of total friction loss. Therefore, research about these friction pairs under different working condition will be helpful to reduce friction loss of diesel engine and improve mechanical efficiency and fuel economy.Cylinder liner-piston rings and crank shaft are analyzed in this paper. Electric motor is applied to drive shafting system. Cylinder cover, fuel ejection, cooling and air supply system have been removed. Additional air hole has been drilled between two piston ring grooves to supply compressed air from top of piston where air hole connected to. With compressed air, pressure of piston rings during ignition has been simulated. Oil proof seal ring is used to connect cylinder liner and cylinder block, which have been treated with thinning process to reduce weight Based on the preparation above, a test bench is designed and built to measure the friction of diesel engine by floated cylinder liner and simulated backpressure loading method. The varying mechanism of their friction work under different rotate speed, temperature and backpressure of piston rings are investigated. Testing results are as follows:(1)The test method which is designed and established in this paper can measure the friction work of cylinder liner-piston-piston rings friction pair and crank-link friction pair with high sensitivity. Through components simulation experiment, the influence of peak pressure of combustion chamber to the friction work can be analyzed.(2)Under the same temperature and back pressure, when the rotate speed vary from 200r/min-800r/min, friction work between cylinder liner-piston-piston rings rising gradually firstly and lower finally. Friction work of crank-link mechanism rises with the increase of speed from the beginning to the end.(3)Under the same rotate speed and back pressure, when the temperature vary from 15-90℃, friction work of cylinder liner-piston-piston rings and crank-link mechanism both rising with the increase of temperature.(4)Under the same rotate speed and temperature, when the working load vary from 0MPa-9MPa, friction work of cylinder liner-piston-piston rings and crank-link mechanism both rising with the increase of back pressure.