Diesel Engine Tappet Wear Analysis And Improvement

Valve train is one of the main component of diesel engine.It’s the key point of the engine combustion organization.The driving parts control the valve movements.Then the air can go into the cylinder and the exhaust can go out as needed.When the camshaft is in the cylinder block,the driving components mainly contain camshaft,tappet,push rod,rocker arm,etc.The camshaft is driven by gears and the speed ratio with crankshaft is 1:2.The cam pushes the tappet and the tappet moves along the tappet hole and the movements are vertical and return.The rocker arm is a lever which transmits the force from cam side to valve side.To let the valve move,the cam has to overcome the gas force from the valve side.That causes a big contact pressure between cam and tappet.To achieve the emission standard,based on mechanical diesel engine,the electronic engine is developed.The new engine is 6 cylinders in line.The PCP and rated speed is more competitive than current engine.The cam shaft is in the cylinder block and the camshaft,push rod,rocker arm is optimized.The tappet is cylindrical and flat subface.After the durability test,the tappet wear was detected.To learn the failure cause,the analysis about material,hardness,surface treatment and structure was done.And the simulation and test was done to get more details.Set up one-dimensional model,and calculate the valve train dynamic characters in different conditions.Do the parts test on separate parts test-bed to save the test resource and development cycle.Implement the optimization design and do the durability test again.No wear is detected on tappet surface.