Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia; Jockey Club Heavy Vehicle Emissions Testing and Research Centre, Vocational Training Council, Hong Kong.
Centre for Green Technology, School of Civil and Environmental Engineering, University of Technology Sydney, NSW 2007, Australia.
Sci Total Environ. 2020 May 10;716:137066. doi: 10.1016/j.scitotenv.2020.137066. Epub 2020 Feb 1.
The deterioration of emissions control systems in a spark ignition engine is predominantly a gradual process of wear and tear occurring as vehicles accumulate mileage. As new innovations in engine and emissions technology have been progressively introduced to meet lower emissions targets, the impact of gradual deterioration of hardware has become more challenging to identify and quantify in the repair industry. When a pioneering emissions control programme utilising remote sensing to detect high emitting gasoline and liquefied petroleum gas (LPG) vehicles was to be introduced in Hong Kong, it became apparent the repair industry needed specialised training to assist with identifying the types of failures which would lead to high vehicle emissions. To identify the impact of hardware deterioration and failures, a Toyota Crown Comfort LPG taxi was used to demonstrate simulated failures of engine hardware systems to measure their impact on emissions, fuel consumption and drivability using a chassis dynamometer. This novel study simulated a broad range of deterioration and failures covering the intake, fuel supply, ignition, and exhaust systems. The results of the study showed significant THC and CO increases of up to 317% (0.604 g/km) and 782% (5.351 g/km) respectively for a simulated oxygen sensor high voltage fault and a sticky mixture control valve. The largest increase in NO emissions was for restricted main fuel supply in the LPG vapouriser, producing an increase of 282% (1.41 g/km). Fuel consumption varied with increases of up to 15.5%. Drivability was impacted with poor idle from a number of faults and especially by a worn throttlebody which produced rough acceleration characteristics as well. This study clearly highlights the importance of having properly maintained emissions and engine hardware systems to achieve optimal fuel economy and compliant emissions levels, which could be reproduced in other regions for prescribed emissions regulation.
火花点火发动机排放控制系统的恶化主要是车辆行驶里程增加导致的磨损逐渐加剧的过程。随着发动机和排放技术的新创新逐步引入以满足更低的排放目标，硬件逐渐恶化的影响在维修行业中更难以识别和量化。当香港推出一项利用遥感技术检测高排放汽油和液化石油气 (LPG) 车辆的开创性排放控制计划时，很明显，维修行业需要专门的培训来协助识别导致车辆排放过高的故障类型。为了识别硬件恶化和故障的影响，使用一辆丰田皇冠舒适型 LPG 出租车来模拟发动机硬件系统的故障，使用底盘测功机测量它们对排放、燃油消耗和驾驶性能的影响。这项新颖的研究模拟了广泛的恶化和故障，涵盖了进气、燃油供应、点火和排气系统。研究结果表明，模拟氧气传感器高压故障和粘性混合气控制阀分别导致 THC 和 CO 显著增加，最高可达 317%（0.604g/km）和 782%（5.351g/km）。LPG 汽化器中主燃料供应受限导致 NO 排放最大增加，增加了 282%（1.41g/km）。燃油消耗随增加高达 15.5%而变化。由于多个故障以及特别是由于节气门体磨损导致怠速不良，驾驶性能受到影响，节气门体磨损导致加速特性粗糙。这项研究清楚地强调了保持排放和发动机硬件系统得到适当维护以实现最佳燃油经济性和合规排放水平的重要性，这可以在其他地区为规定的排放法规进行复制。
