Valve Timing Based Optimization of Diesel Engine with High Exhaust Back Pressure

For the problems of larger pump loss,higher residual gas coefficient and worse fuel economy at high exhaust back pressure,the scheme of optimizing the valve timing was put forward.With GT-Power software,the model of LD1110 singlecylinder diesel engine was built and the optimization of valve timing was analyzed.The results showed that the brake mean effective pressure(BMEP)and the brake specific fuel consumption(BSFC)improved by 28.33% and 22.08% respectively by optimizing the exhaust late close angle at 2 200r/min with 0.3 MPa exhaust back pressure,45 mg fuel injection per cycle and constant intake valve timing.When the exhaust back pressure increased from 0.1MPa to 0.3MPa at 2 000r/min,the BMEP loss and the BSFC increase could decrease by 12.8% and 27.1% respectively.