氩氧氛围下天然气缸内燃烧的离子电流特性

Study on Ion Current of Natural Gas in Cylinder under Ar/O2 Atmosphere

摘要:

在一台改装的直列双缸火花点火发动机上，将进气由空气改为具有更高比热比的氩气和氧气的混合气，进气道喷射天然气，研究了氩-氧氛围下天然气缸内燃烧的离子电流特性。结果表明，相比于空气氛围，氩-氧氛围下缸内离子电流信号强度显著增强；在氩气体积分数为79%及以下时，离子电流信号特征值与基于缸压计算的燃烧特征值具有很强的一致性；离子电流信号能够检测缸内的爆震燃烧，具有很好的可靠性，但对爆震强度的敏感程度较弱。

关键词:氩氧氛围;离子电流;天然气发动机;爆震

Abstract:

Experimental study on the effects of Ar-O2 atmosphere on ion current characteristic of natural gas in an SI engine was conducted. Engine fueled by natural gas was modified base on an inline two-cylinder diesel engine. Air was replaced by oxygen and argon (with higher specific heat ratio) mixture as engine intake gas. Results show that the ion current strength increase significantly under Ar-O2 atmosphere compared with air. When argon percentage is 79% or lower, the eigenvalue of ion current is corresponding very well with combustion characteristics calculated by pressure. Ion current can detect knock reliably, but it is insensitive to knock’s intensity.

Key words:Ar/O2 atmosphere; ion current; natural gas engine; knock