Electro-hydraulic variable valve system for hybrid pneumatic-internal combustion engine

YE Jin， LI Dao-fei， WANG Lei， XV Huan-xiang， YU Xiao-li
（Department of Energy Engineering， Zhejiang University， Hangzhou 310027， China）

Abstract： In order to switch among multiple working modes of the concept hybrid engine，including air motor mode，supercharged combustion mode and regenerative braking mode，an electro-hydraulic variable valve system was designed and manufactured. Based on a newly designed prototype，the intake and exhaust valving strategies in different modes were analyzed. The on/off of hydraulic line was controlled with high speed electromagnetic valves. By using NI-CompactRIO platform，the control system hardware and software of valve prototype were designed and optimized. Finally，preliminary tests of the variable valve were conducted. The results indicate that，though there is some dynamic delay of valve lift，by regulating the opening and duration of electromagnetic valves，the optimal lift and timing strategy of the engine valve can be achieved for the air motor mode of the hybrid engine concept.
Key words： hybrid powertrain； pneumatic engine； electro-hydraulic variable valve