农业工程学报2018，Vol.34Issue(7)：1-14,14.DOI:10.11975/j.issn.1002-6819.2018.07.001
农业机械污染排放控制技术的现状与展望
Progress of control technologies on exhaust emissions for agricultural machinery
摘要
Abstract
As an important type of non-road machinery, agricultural machinery plays an important role in national economy. At present, the main power source of agricultural machinery is diesel engine. However, the inherent combustion mode of diesel engine leads to large amounts of pollutant emission such as particulate matter (PM) and nitrogen oxide (NOx), and PM and NOx can cause great damage to human health and ecological environment. Therefore, exhaust emission control technology research for agricultural machinery is of great significance. From 3 aspects, this paper elaborates agricultural machinery emission legislation, individual technical routes to reduce agricultural machinery emissions, and combined technical routes to meet more stringent emission limits. Agricultural machinery emissions legislation part analyzes regulations of the EU (European union), the United States and China on exhaust emission limits, test cycles requirements, and their differences. The current agricultural machinery emission legislation for agricultural machinery in China is Stage Ⅲ. Compared with the standard of Stage Ⅳ implemented by the EU and the standard of Tier Ⅳ implemented by the United States, exhaust emission limits of China Ⅲ are relatively relaxed. Legislation of the EU, the United States and China for agricultural machinery increases the non-road transient cycle (NRTC) from StageⅢB, Tier Ⅳ and China Ⅳ, respectively. Unlike the EU, China and the United States stipulate that agricultural machinery diesel engines of non-constant speed below 19 kW can also be tested under the cycle of 6 working conditions.In EU and China, the final measuring results of exhaust emissions consist of 10% of the cold start and 90% of the hot start, while the United States reduced the proportion of cold start test cycle results to 5%. Ⅰndividual technical routes of agricultural machinery emission control mainly include oil technologies, engine purification technologies, and exhaust after-treatment technologies. Among them, oil technologies include improving the quality of fuel and lubricating oil, use of alternative fuels, and so on. Engine purification technologies include diesel engine optimization design for agricultural machinery, supercharging and supercharged intercooler, fuel injection optimization, and EGR (exhaust gas recirculation). Exhaust after-treatment technologies include DOC (diesel oxidation catalyst) technology, DPF (diesel particulate filter) technology and SCR (selective catalytic reduction) technology. Oil technology is a prerequisite for agricultural machinery exhaust emission control, while engine purification technology is the foundation. Advanced exhaust after-treatment technology is the key to meet stringent emission limits for agricultural machinery. Combined technology routes summarize the methods to meet China Ⅲ and Ⅳ emission limits and the latest foreign emission limits. Diesel engines using the "optimized combustion + SCR" route save 5%-7% fuel compared with diesel engines using the "EGR+ DPF/CDPF (catalytic diesel particulate filter)" route. Deducting urea consumption, the former route still saves 2%-3% fuel. "Optimized combustion + SCR" route is used in the EU commonly, while "EGR + DPF/CDPF" is usually used in the United States. Considering actual situation in China, there is still much room for improvement in fuel quality, but urea production is very common, so the implementation of China Ⅳ legislation prefers SCR. Of course, to find proper routes for agricultural machinery exhaust emission control, it needs to consider the power of agricultural machinery diesel engine, displacement and specific use of the environment, and other requirements. Finally, this paper summarizes the prospects of agricultural machinery emission control technologies. To meet the future China Ⅳlimits, it is a significant measure to install an exhaust after-treatment catalytic converter for agricultural machinery. Developing an integrated exhaust after-treatment catalytic converter with low cost and high purification efficiency may become an important research direction for the future emission control of agricultural machinery.关键词
农业机械/柴油机/排放控制/颗粒物/氮氧化物Key words
agricultural machinery/diesel engines/emission control/PM/NOx分类
能源科技引用本文复制引用
谭丕强,王德源,楼狄明,胡志远..农业机械污染排放控制技术的现状与展望[J].农业工程学报,2018,34(7):1-14,14.基金项目
国家重点研发计划资助(2017YFC0211202) （2017YFC0211202）
