Design And Test Validating Of The Forged Steel Piston

Internal combustion engine industry is one of the industries with multi-technique. Though it has such defects as large noises and pollution etc., Internal combustion engine(ICE) has being widely used in industry, agriculture, traffic and national defence fields due to its high thermal efficiency, excellent dynamic performance, wide range of power and its high reliability. ICE has being in continuous development. And this is based on the development of properties and life-circle of its primary components. As one of the main ICE parts piston plays an important role in the performance parameters of the whole engine. For years, traditional aluminium alloy piston has been becoming harder and harder to meet the continuously strengthened requirements and severe emission regulations(Euro III,Euro IV,Euro V).It becomes essential to design new type piston when aluminium alloy piston can't adapt the engine's reliability any more, especially when peak pressure is up to 20MPa and more. After introducing overseas design experience for forged steel piston, we designed a new-structured forged steel piston based on 6D diesel engine belongs to a domestic company. The piston was adopted large-areaed internal cooling gallery structure and optimized the profile and the oval of cross sections. The manufacturing process was also optimized by using friction welding technic. Finite element analysis(FEA) was run on FEA software to predict the temperature, stress and fatigue life of the piston on the basis of dynamics and thermodynamics theorys. The results indicated that the piston can meet the reliability requirement of the engine well. The thesis also gave further brief introduction of friction welding technic, manufacturing process, and validated the piston by integrated tests which includes pin bore fatigue test, thermal field test, marking test, scuff test and 1000-hour reliability test etc.. The piston passed all the tests and fulfilled the emission requirement. On all the tests above we can draw a conclusion that the forged steel piston has higher reliability, lower oil consumption and blow-by compared with aluminium alloy piston. Above all we can conclude that the forged steel piston meet the whole engine requirements, and now it has been used in heavy diesel engine successfully.