Technical Paper
Electronic Continuous Variable Valve Timing for Small SI Engine
2008-06-23
2008-01-1778
An electronic variable valve timing system for a spark ignition engine was designed and built in order to investigate the performance of ideal valve actuation timing and facilitate further research. The solenoid actuated EVVT system was installed on a single cylinder 80 ccm, 1.7 kW Briggs & Stratton SI engine. The system is controlled by a PIC micro-controller unit, which in turn controls a 120V solenoid driver circuit to power the solenoids. The continuous variable valve timing adjustment enables ideal combustion conditions during all speed ranges and loads. This leads to cleaner, more efficient and more powerful combustion once the control algorithm is mapped for all conditions. Furthermore, it makes controlled auto ignition achievable using negative valve overlap, which is a promising emission-reducing combustion mode.