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在过去的20年里,柴油机制造商面临着严格的氮氧化物和颗粒排放法规。为了应对排放的挑战,已运用了涡轮增压、废气再循环、高压共轨燃油喷射系统、柴油机排气后处理装置,以及发动机电子控制等多项技术。柴油机制造商面临的下一个挑战将是2014年开始实施的燃油经济性法规。作为应对该法规的序幕,美国能源部资助了1个“超级卡车”项目,旨在底盘测功器上展示50%的有效热效率,同时满足US 2010排放标准。为了低成本地满足排放和发动机效率目标,发动机制造商采取了系统性措施,因为单个节油技术具有局限性,不一定能在整车方面得到节油效果。着手的优化研究包括燃烧改进、后处理和余热回收技术。围绕2个典型的行驶循环模式工况点,扼要叙述了其试验结果。选定的发动机结构决定了后处理、燃烧和余热回收方法之间的折中。分别探讨了与高、低氮氧化物方法关联的高温和低温燃烧系统,以及为每种结构配置的发动机硬件。针对高、低氮氧化物燃烧模式,研究了以不断提高的喷油轨压实现的燃烧改进,以及以电子涡轮复合形式实现的余热回收。
For the past two decades, diesel engine manufacturers have been confronted with stringent NOx and particulate regulations. In order to meet the emission challenge, a number of technologies such as turbocharging, exhaust gas recirculation, high pressure common rail fuel injection systems, diesel exhaust aftertreatment devices, and engine electronic control have been utilized. The next challenge for diesel manufacturers will be the fuel economy regulations that will come into force in 2014. As a prelude to this rule, the U.S. Department of Energy funded a Super Truck project to demonstrate 50% effective thermal efficiency on chassis dynamometers while meeting US 2010 emission standards. Engine manufacturers have taken systematic steps to meet their emission and engine efficiency targets at a low cost because of the limitations of individual fuel economy technologies that may not necessarily result in fuel savings in the vehicle. Optimization studies that begin with include combustion improvement, aftertreatment, and waste heat recovery technologies. Around 2 typical driving cycle mode operating conditions, the experimental results are briefly described. The selected engine configuration determines the trade-off between aftertreatment, combustion and waste heat recovery methods. The high temperature and low temperature combustion systems associated with the high and low NOx approaches, respectively, and the engine hardware configured for each configuration were explored separately. For high and low NOx combustion modes, combustion improvements with increasing rail pressure were investigated, as well as waste heat recovery in the form of electronic turbine compounding.