The quadratic regression orthogonal composite experiments were performed on a modified ZH1115 type diesel/LPG dual fuel engine to study the influence of different operating conditions on the smoke emissions. The effect of advanced injection angle

injection pressure and mixed burning ratio of diesel/LPG

as well as their interaction on smoke emissions was analyzed on their influences on the smoke. The experimental results show that the effect of experimental factors on smoke emissions is a complex nonlinear function

and the interaction between these test factors has a significant effect on smoke emissions. The lowest smoke emissions could be achieved when the advanced injection angle

the injection pressure and diesel/LPG mixed burning ratio are taken as 27.2°

19 MPa and 1.94∶0.60 respectively.