EGR strategy for DME engine‐out NOx to meet euro V

In this article, a 2102QB diesel engine was retrofitted to run on DME. The effects of EGR on the DME engine power output, DME fuel consumption, and emission characteristics were investigated. Experimental results show that, DME engine power and fuel economy are both improved. The stoichiometric air/fuel ratio of DME is 9/1. DME engine can run properly if the air/fuel ratio is leaner than that due to the introduction of EGR. Only under fuel rich conditions, DME engine power output, fuel economy, HC and CO emissions become worse. NOx emissions can be reduced easily by the use of EGR. Based on the experimental data, the specific NOx emissoin was calculated and then it was used to set the rate of EGR under the ESC 13 operating conditions. By the designed EGR strategies, the DME engine NOx emissions under ESC operating conditions meets the requirement of Euro IV and V. At the mean time, HC and CO emissions of the DME engine were evaluated. The increase of CO and HC emissions require oxidation after treatment to meet their own standards. (c) 2014 American Institute of Chemical Engineers Environ Prog, 2014 34: 881-889, 2015