A Flexible, Electronically Controlled, Hydraulically Actuating Variable Valve System for Diesel Engine 2002-01-2173
An engine valve actuation system, called Electronic Hydraulic Variable Valve System (EHVVS), has been developed and tested for the first time. It is hydraulically actuated and electronically controlled. The valve springs are reserved to provide force for the valve to close. It consists of a common oil rail, an electronic hydraulic valve actuator, a Fast-Respond Powerful Great-flow (FPG) three-way solenoid valve, and a single-chip micro controller system to actuate engine poppet valve. In the EHVVS, the valve timing and duration can be changed easily by increasing or decreasing the high-level period of the signals to control the solenoid valve. Part-lift operation is also possible, which can be obtained either by decreasing the common oil rail pressure or by shortening the period of the signal to control the solenoid valve. The performance of the system has been analyzed in adjustable capability, matching capability for the engine, seating velocity and energy requirements by experiments and calculation. It is demonstrated that the EHVVS is a flexible, controllable, reliable variable valve system with good capability to vary timing, duration and lift, lower seating velocity and less energy require-ment. The prototype system has been run on the bench on an actual model 2135 diesel engine cylinder head at speed of 1500r/min. On the whole, it can meet the requirement of the primary design goal, and can be easily retrofitted onto the existing model 2135 engine. It might be used to improve the intake and exhaust system of model 2135 engine and the same type series diesel engines.