An Experimental Investigation on the Combustion and Heat Release Characteristics of an Opposed-Piston Folded-Cranktrain Diesel Engine

Fukang Ma,Changlu Zhao,Zhaoyi Xie,Zhenfeng Zhao,Fujun Zhang,Hao Wang,Zhenyu Zhang

doi:10.3390/en8076365

Fukang Ma, Changlu Zhao + Show 5 more

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https://doi.org/10.3390/en8076365

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Abstract

In opposed-piston folded-cranktrain diesel engines, the relative movement rules of opposed-pistons, combustion chamber components and injector position are different from those of conventional diesel engines. The combustion and heat release characteristics of an opposed-piston folded-cranktrain diesel engine under different operating conditions were investigated. Four phases: ignition delay, premixed combustion, diffusion combustion and after combustion are used to describe the heat release process of the engine. Load changing has a small effect on premixed combustion duration while it influences diffusion combustion duration significantly. The heat release process has more significant isochoric and isobaric combustion which differs from the conventional diesel engine situation, except at high exhaust pressure and temperature, due to its two-stroke and uniflow scavenging characteristics. Meanwhile, a relatively high-quality exhaust heat energy is produced in opposed-piston folded-cranktrain diesel engines.

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]
Based on the differences between opposed-piston folded-cranktrain (OPFC) diesel engines and conventional diesel engines, this study aims to analyze the OPFC diesel engine rate of heat release (ROHR) and combustion characteristics and evaluate the effect of the unique combustion system and opposed-piston relative movement rule on the performance and combustion characteristics of OPFC diesel engines by using a ROHR and waste heat exergy analysis
The peak cylinder gas pressure (CGP) mainly depends on combustion rate in the initial stages, which is influenced by the fuel participating in the uncontrolled heat release (HR) phase

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 measures for diesel engines. They have focused their study and practice on new types of diesel engines, too [3,4,5]. In the first half of the 20th century, the OP2S engine concept was developed in multiple countries for a wide variety of applications, modern emissions regulations essentially put an end to the spread of two-stroke engines in the latter half of the 20th century [6]. With the application of advanced design technology, modern analytical tools, materials and engineering technology development, electrical assisted turbochargers and high pressure common rail injection technology, the emission problem is no longer a limiting factor for the successful design of a clean and efficient OP2S engine [7], OP2S engines have again attracted intensive attention to improve the engine efficiency and emissions [8,9]

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