重型柴油机预热器结构改进分析

Structure Improvement Analysis of Heavy Duty Diesel Engine Preheater

摘要:

通过对两款预热器进行台架试验和对比分析，提出了燃油预热器结构对其工作效率提高具有重要影响，同时提出了燃油预热器结构改进的方向，即在燃烧室内加装扰流板.利用CFD软件对加装了扰流板的燃烧室进行仿真分析，分别得到了不同的扰流板位置和不同扰流板尺寸下燃烧室的温度分布云图、CO分布云图以及O2分布云图.通过对比分析发现：扰流板的最佳直径为70 mm，与无扰流板的设计相比，燃油预热器效率提高了17%；扰流板的最佳位置为距离底部80 mm，与原扰流板距离底部60 mm的旧设计结构相比，燃油预热器的效率提高了11.4%.

关键词:柴油机; 燃油预热器; 优化; 结构改进

Abstract:

The vehicle fuel preheater is an important and effective means to improve operating condition during cold engine starting. A conclusion is reached that the fuel preheater improves operating efficiency of the engine effectively through a series of tests and analyses. A more efficient way to improve operating efficiency of fuel preheater is to install spoiler in the combustion chamber. In this paper, the CFD software is used to simulate the preheater combustion chamber installed spoiler. The temperature distribution, CO distribution, and O2 distribution of the combustion chamber are obtained at different spoiler locations and different spoiler sizes. The comparative analysis indicate that the optimal spoiler diameter is 70 mm, compared with the nonspoiler design, and the fuel preheater efficiency is increased by 17%. The optimal position of the spoiler is 80 mm from the bottom, and the efficiency of the fuel preheater is 11.4% higher than the original design in which the spoiler is 60 mm from the bottom spoiler.

Key words:diesel engine; fuel preheater; optimization; structural improvement