A High-Efficiency Two-Stroke Engine Concept: The Boosted Uniflow Scavenged Direct-Injection Gasoline (BUSDIG) Engine with Air Hybrid Operation  

一种高效的二冲程发动机概念——结合空气混合动力系统的增压直流扫气式直喷汽油(BUSDIG)发动机

作　　者：Xinyan Wang Hua Zhao 

机构地区：[1]Center for Advanced Powertrain and Fuels, Brunel University London, Uxbridge UB8 3PH, UK

出　　处：《Engineering》2019年第3期535-547,共13页工程（英文）

基　　金：financial support from the Engineering and Physical Sciences Research Council (EPSRC)

摘　　要：A novel two-stroke boosted uniflow scavenged direct-injection gasoline (BUSDIG) engine has been proposed and designed in order to achieve aggressive engine downsizing and down-speeding for higher engine performance and efficiency. In this paper, the design and development of the BUSDIG engine are outlined discussed and the key findings are summarized to highlight the progress of the development of the proposed two-stroke BUSDIG engine. In order to maximize the scavenging performance and produce sufficient in-cylinder flow motions for the fuel/air mixing process in the two-stroke BUSDIG engine, the engine bore/stroke ratio, intake scavenge port angles, and intake plenum design were optimized by three-dimensional (3D) computational fluid dynamics (CFD) simulations. The effects of the opening profiles of the scavenge ports and exhaust valves on controlling the scavenging process were also investigated. In order to achieve optimal in-cylinder fuel stratification, the mixture-formation processes by different injection strategies were studied by using CFD simulations with a calibrated Reitz–Diwakar breakup model. Based on the optimal design of the BUSDIG engine, one-dimensional (1D) engine simulations were performed in Ricardo WAVE. The results showed that a maximum brake thermal efficiency of 47.2% can be achieved for the two-stroke BUSDIG engine with lean combustion and water injection. A peak brake toque of 379 N·m and a peak brake power density of 112 kW·L^-1 were achieved at 1600 and 4000 r·min^-1, respectively, in the BUSDIG engine with the stoichiometric condition.A novel two-stroke boosted uniflow scavenged direct-injection gasoline（BUSDIG）engine has been proposed and designed in order to achieve aggressive engine downsizing and down-speeding for higher engine performance and efficiency.In this paper,the design and development of the BUSDIG engine are outlined discussed and the key findings are summarized to highlight the progress of the development of the proposed two-stroke BUSDIG engine.In order to maximize the scavenging performance and produce sufficient in-cylinder flow motions for the fuel/air mixing process in the two-stroke BUSDIG engine,the engine bore/stroke ratio,intake scavenge port angles,and intake plenum design were optimized by three-dimensional（3 D）computational fluid dynamics（CFD）simulations.The effects of the opening profiles of the scavenge ports and exhaust valves on controlling the scavenging process were also investigated.In order to achieve optimal in-cylinder fuel stratification,the mixture-formation processes by different injection strategies were studied by using CFD simulations with a calibrated Reitz-Diwakar breakup model.Based on the optimal design of the BUSDIG engine,one-dimensional（1D）engine simulations were performed in Ricardo WAVE.The results showed that a maximum brake thermal efficiency of 47.2% can be achieved for the two-stroke BUSDIG engine with lean combustion and water injection.A peak brake toque of 379 N.m and a peak brake power density of 112 kW·L-1 were achieved at 1600 and 4000 r·min-1,respectively,in the BUSDIG engine with the stoichiometric condition.

关 键 词：TWO-STROKE ENGINE Uniflow SCAVENGING ENGINE design simulation SCAVENGING performance Thermal efficiency 

分 类 号：N[自然科学总论]