Book Description

The engine industry is currently facing severe emissions mandates. Pollutant emissions from mobile sources are a major source of concern. For example, US EPA mandates require emissions of particulate and nitrogen oxides (NOx) from heavy-duty diesel engine exhaust to drop at least 90 percent between 1998 and 2010. Effective analysis of the combustion process is required to guide the selection of technologies for future development since exhaust after-treatment solutions are not currently available that can meet the required emission reduction goals. The goal of this project is to develop methods to optimize and control Low Temperature Combustion Diesel technologies (LTC-D) that offers the potential of nearly eliminating engine NOx and particulate emissions at reduced cost over traditional methods by controlling pollutant emissions in-cylinder. The work was divided into 5 Tasks, featuring experimental and modeling components: 1.) Fundamental understanding of LTC-D and advanced model development, 2.) Experimental investigation of LTC-D combustion control concepts, 3.) Application of detailed models for optimization of LTC-D combustion and emissions, 4.) Impact of heat transfer and spray impingement on LTC-D combustion, and 5.) Transient engine control with mixed-mode combustion. As described in the final report (December 2008), outcomes from the research included providing guidelines to the engine and energy industries for achieving optimal low temperature combustion operation through using advanced fuel injection strategies, and the potential to extend low temperature operation through manipulation of fuel characteristics. In addition, recommendations were made for improved combustion chamber geometries that are matched to injection sprays and that minimize wall fuel films. The role of fuel-air mixing, fuel characteristics, fuel spray/wall impingement and heat transfer on LTC-D engine control were revealed. Methods were proposed for transient engine operation during load and speed changes to extend LTC-D engine operating limits, power density and fuel economy. Low emissions engine design concepts were proposed and evaluated.