The Optimization And Design Of Performance For New Marine Middle-speed Diesel Engine

Not only can the four-stroke medium speed diesel engine be used as a generator's prime mover, but also it can be used as main propulsion plant on vessels. The optimization of the diesel engine can improve production level of the domestic diesel engine. The calculations of medium speed diesel engine' working process could provide direction for its working performance. Faults-simulation research could provide reference for trouble shooting which is good for its working life. The valve gear multi-body system dynamic simulation forecast its movement and force through virtual prototype. This reduces production cost. The fuel injection system's performance optimization supplies design suggestions for its good work. The research work as follows:(1) CM-6L21/32 marine middle-speed diesel engine is chosen as the research object. Making use of AVL Boost software establish zero-dimension numerical model. According to test data, verify the validity of the model. Based on this, CM-6L21/32 model is established, get the indicator diagram, gas-flow and pressure curves at inlet or outlet and load characteristic curves. This is provided as guidance for the diesel engine production design. After CM -6L21/32 is in production, it can be used to test model validity. In addition,8 faults simulation calculation is conducted on CM-6L21/32 and 14 performance parameters are extracted to reflect the engine performance. The simulation results show that different faults have different affections on the performance of engine and this provides an important basis for diesel engine fault prediction.(2) CM-6L21/32 marine middle-speed diesel engine's valve gear is chosen as research object, kinematics and dynamics simulation model is constructed by using of MSC.ADAMS software to get dynamic and kinematic parameters. Dynamic parameters include:contact stress between valve and valve seat, cam and tappet, valve and rocker. Kinematic parameters include:displacement, velocity and acceleration of valve. After their comparison with the similar type of diesel engine's values, they are in the allowed limits.(3) CM-6L21/32 marine middle-speed diesel engine's fuel injection system as the research object. Its simulation model of working process is built by the use of AVL Hydsim software. Change fuel injection pump plunger diameter, high-pressure tube length and diameter, injector holes'number and the diameter of holes so on, analyze their affections to fuel injection system needle valve lift, fuel Injection quantity and fuel injection pressure. This can supply reference for its performance optimization.