Dynamic Simulation of Engine Based on Variable Inertia and Multi-body Crankshaft System

The dynamic model of engine was established by analyzing the inertia of connecting rod,the friction torque of piston and the indicating torque of gas pressure with the Lagrange equation.With the internal point coordinate and equation of ADAS software,the parameterized graphics user interface(GUI) that integrated the crankshaft structure parameters,the friction torque,the load torque and the ignition order was developed.The crankshaft modal neutral file was acquired by the flexible treatment of crankshaft,the multi-body dynamics virtual prototype was built by importing the ADAMS/FLEX module into ADAMS software and finally the dynamic simulation was carried out on an engine.The simulation results show that the engine effective output torque is influenced by the friction torque and variable inertia torque.Compared with the rigid crankshaft,the flexible crankshaft can simulate the actual engine crankshaft more accurately.Accordingly,the model is suitable for the vehicle dynamic performance simulation and its produced accurate load is helpful for the design,strength verification and lifetime calculation of crankshaft.