Sutdy of drive circuit for the control of needle lift of direct acting common rail system

YANG Tengfei, ZHOU Wenhua, ZHANG Yue

 

(Department of Energy Engineering, Zhejiang University, Hangzhou 310027, China)

 

 

Abstract: Aiming at the control of the injection rate of diesel engine, control methods of injection rate were summarized. Based on the analyses of the advantages of direct acting common rail system and the control method of needle of the direct acting piezoelectric injector, the charge and discharge strategies were analyzed and a drive circuit was designed. The thought of variable resistance was applied to the design of the voltage feedback circuit to control the driving voltage. By choosing the feedback resistances, the stairlike control of driving voltage and needle lift were realized. The drive circuit designed was optimized by simulation and verified by experiment, using the existing piezoelectric actuator. The results show that the charge period and discharge period are both about 120μs. The change of driving voltage between different values is in 100μs, which meets the requirement of the needle lift. The drive circuit can control the injection rate by changing the driving voltage during the injection process.

 

Key words: direct acting; piezoelectric actuator; drive circuit; needle lift