Parameter Optimization on the Uniflow Scavenging System of an OP2S-GDI Engine Based on Indicated Mean Effective Pressure (IMEP)

Fu-Kang Ma,Yan-Gang Zhang,Jun Wang,Yi Zhang,Yu-Hang Liu,Yao-Nan Feng,Tie-Xiong Su

doi:10.3390/en10030368

Fu-Kang Ma, Yan-Gang Zhang + Show 5 more

Open Access

https://doi.org/10.3390/en10030368

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Abstract

In this paper, an opposed-piston two-stroke (OP2S) gasoline direct injection (GDI) engine is introduced and its working principles and scavenging process were analyzed. An optimization function was established to optimize the scavenging system parameters, include intake port height, exhaust port height, intake port circumference ratio, the exhaust port circumference ratio and opposed-piston motion phase difference. The effect of the port height on the effective compression ratio and effective expansion ratio were considered, and indicated mean effective pressure (IMEP) was employed as the optimization objective instead of scavenging efficiency. Orthogonal experiments were employed to reduce the calculation work. The effect of the scavenging parameters on delivery ratio, trapping ratio, scavenging efficiency and indicated thermal efficiency were calculated, and the best parameters were also obtained by the optimization function. The results show that IMEP can be used as the optimization objective in the uniflow scavenging system; intake port height is the main factor to the delivery ratio, while exhaust port height is the main to engine trapping ratio, scavenging efficiency and indicated thermal efficiency; exhaust port height is the most important factor to effect the gas exchange process of OP2S-GDI engine.

Highlights

Pressured by the energy crisis and environmental pollution, the car industry is faced with unprecedented challenges due to its high energy consumption and pollution emissions [1,2]
Ratio,trapping trapping efficiency and scavenging efficiency were employed usually employed as Delivery efficiency and scavenging efficiency were usually as evaluation evaluation index on the two-stroke system
Delivery ratio increases with the raise last time, that the mass flow of flow the intake scavenging lastimproves time, that improves therate mass rate ofport

Summary

Introduction

Pressured by the energy crisis and environmental pollution, the car industry is faced with unprecedented challenges due to its high energy consumption and pollution emissions [1,2]. Over the past two decades, researchers and manufacturers have proposed effective energy-saving and emission reduction methods. They have focused their study and practice on new types of engines too [3,4,5]. OP2S engines are different from conventional engines in structure and have better fuel efficiency, power density and balance performance [3]. Compared with conventional engines opposed-piston engines have some advantages such as high power density, low heat transfer loss and mean piston velocity, and good balance performance [5]. The emission performance is worse because of the high oil consumption.

Results

Discussion

Conclusion