Quantitative planar laser-induced fluorescence imaging of multi-component fuel/air mixing in a firing gasoline-direct-injection engine: Effects of residual exhaust gas on quantitative PLIF

被引：47

作者：

Williams, Ben

Ewart, Paul ^{[1
]}

Wang, Xiaowei ^{[2
]}

Stone, Richard ^{[2
]}

Ma, Hongrui ^{[3
]}

Walmsley, Harold ^{[3
]}

Cracknell, Roger ^{[3
]}

Stevens, Robert ^{[4
]}

Richardson, David ^{[4
]}

Fu, Huiyu ^{[4
]}

Wallace, Stan ^{[4
]}

机构：

[1] Univ Oxford, Dept Phys, Clarendon Lab, Parks Rd, Oxford OX1 3PU, England

[2] Univ Oxford, Dept Engn Sci, Oxford OX1 3PJ, England

[3] Shell Global Solut UK, Shell Res Ctr Thornton, Chester CH1 3SH, Cheshire, England

[4] Jaguar Cars, Ctr Engn, Coventry CV3 4LF, W Midlands, England

来源：

COMBUSTION AND FLAME | 2010年 / 157卷 / 10期

基金：

英国工程与自然科学研究理事会;

关键词：

Quantitative PLIF; Fuel/air mixing; Gasoline engines; Direct injection; Exhaust gas residuals; DROPLET VAPORIZATION; COMBUSTION; TEMPERATURE; RATIO; DIAGNOSTICS;

D O I：

10.1016/j.combustflame.2010.06.004

中图分类号：

O414.1 [热力学];

学科分类号：

摘要：

A study of in-cylinder fuel-air mixing distributions in a firing gasoline-direct-injection engine is reported using planar laser-induced fluorescence (PLIF) imaging. A multi-component fuel synthesised from three pairs of components chosen to simulate light, medium and heavy fractions was seeded with one of three tracers, each chosen to co-evaporate with and thus follow one of the fractions, in order to account for differential volatility of such components in typical gasoline fuels. In order to make quantitative measurements of fuel-air ratio from PLIF images, initial calibration was by recording PLIF images of homogeneous fuel-air mixtures under similar conditions of in-cylinder temperature and pressure using a re-circulation loop and a motored engine. This calibration method was found to be affected by two significant factors. Firstly, calibration was affected by variation of signal collection efficiency arising from build-up of absorbing deposits on the windows during firing cycles, which are not present under motored conditions. Secondly, the effects of residual exhaust gas present in the firing engine were not accounted for using a calibration loop with a motored engine. In order to account for these factors a novel method of PLIF calibration is presented whereby 'bookend' calibration measurements for each tracer separately are performed under firing conditions, utilising injection into a large upstream heated plenum to promote the formation of homogeneous in-cylinder mixtures. These calibration datasets contain sufficient information to not only characterise the quantum efficiency of each tracer during a typical engine cycle, but also monitor imaging efficiency, and, importantly, account for the impact of exhaust gas residuals (EGR). By use of this method EGR is identified as a significant factor in quantitative PLIF for fuel mixing diagnostics in firing engines. The effects of cyclic variation in fuel concentration on burn rate are analysed for different fuel injection strategies. Finally, mixture distributions for late injection obtained using quantitative PLIF are compared to predictions of computational fluid dynamics calculations. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

引用

页码：1866 / 1878

页数：13