The effects of intake VVT on the BSFC and combustion characteristics of a gasoline engine with low pressure EGR were studied based on a port fuel injection gasoline engine of small displacement with a low pressure EGR system. Results show that the smaller the EGR rate

the greater the pump loss

and when the EGR rate is small

the variation of the pump loss with EGR rate is also small

and vice versa; besides

the pump loss decreases when the intake valve open time is advanced or retarded. At 1850 r/min and 0.45 MPa

when the intake valve open timing is set at 10° and 28° before TDC

as well as 24° after TDC

the pump loss decreases by 2.3%

11.9% and 18.8% respectively; when the open timing is advanced to before TDC or lagged behind after TDC with higher EGR

the combustion duration and ignition delay increases and the BSFC decreases. The lowest BSFC is 283.44 g/(kW•h) achieved by the optimization of the EGR rate and intake valve open timing

and it decreases by 3.8% compared with the original one of 294.49 g/(kW•h).