NUMERICAL ANALYSIS OF HOMOGENEOUS MIXTURE FORMATION FOR A DIRECT INJECTION LIQUID LPG ENGINE |
B. Y. XU1, X. C. ZHANG1, J. XU2, Y. L. QI1, S. L. CAI3 |
1Shandong Jianzhu University 2Shandong Academy of Science 3Jinan University |
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ABSTRACT |
A method to form a homogeneous mixture using low pressure direct injection of liquid phase LPG, pent-roof combustion chamber, flat-top piston and center-located injector layout is presented. To validate the method, the mixture formation processes in the cylinder were investigated using the CFD code. The effect of different injection timing and engine loads on the mixture formation processes were researched. The simulated results showed that, the intake tumble for high load conditions or the inclined intake swirl for part load conditions would break into small-scale vortex (turbulence) near the end of compression stroke, which enhanced the homogeneous mixture formation. The results also showed that if the liquid phase LPG was injected at 60-80oCA ATDC in intake stroke even at different loads, the homogeneous mixture would be formed under any engine load conditions. |
Key Words:
Liquid phase LPG, Low pressure direct injection, Homogeneous mixture, Numerical analysis |
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