Abstract
Keywords:
Variable valve timing (VVT), Brake specific fuel consumption (BSFC), Exhaust gas recirculation (EGR)
Abstract
Variable Valve Timing (VVT) system can be used to improve fuel economy, performance and emissions. This paper describes the effect of VVT in terms of wide open throttle torque, residual gas content, intake manifold pressure, pumping losses and fuel economy. Engine cycle simulations are performed on 2.5L gasoline in-line 6-cylinder engine by using WAVE of Ricardo. Results of the simulations had good agreement with WOT torque experimental data, and helped to predict the tendency of fuel economy as the valve timings change. WOT torque was higher when intake valves were closed early for low rpm and late for high rpm. Fuel consumption of part load was improved as the valve overlap increases by the internal EGR at BMEP 2bar condition.