Development of a piezoelectrically-controlled hydraulic actuator for a camless engine. Part 1: system design

A camless engine proof-of-concept prototype was completed on the basis of the use of piezoelectric control of a hydraulic actuator. This novel approach was taken in an attempt to enhance earlier solenoid-based camless engine prototypes, several of which are reviewed as an introduction to camless engine technology. Following a historical review, an overview of the piezoelectrically-controlled camless engine actuator is discussed. The prototype system is capable of displacing an engine valve up to 12.4 mm, and valve actuation frequencies of up to 500 Hz have been obtained. The proof of concept can be considered successful, as it demonstrates the potential of piezoelectric control of hydraulics for use as an internal combustion engine valve actuator. Furthermore, in conjunction with variable timing, the piezoelectric control based pilot allows for direct regulation of other engine valve parameters including variable lift and seating velocity.