Design of Cam Profile Based on Miller-Cycle

The necessity which high-order polynomials are used for optimization design of cam profile is analyzed in valve train of high-speed engines. Basing on the basic idea of Miller-cycle delayed intake valve closing time to reduce the compression ratio, this method is used for re-optimize design of the cam profile in CY4D47 diesel engine. The general method is given by the five-order polynomial. So, the improved cam profile equations can be obtained, then, the lift, velocity, acceleration and Jerk curves are got, lastly, the cam profile are drew by AutoCAD soft.