Effective Use of EGR Rate to Reduce NOx and Soot using Multiple Injections in Light Commercial Diesel Engines 2013-01-2424

Exhaust gas recirculation is one important measure to achieve the Bharat Stage IV, Bharat Stage V as well as the Euro V emissions legislation. EGR is one of the most promising solutions to reduce NOx to achieve Bharat Stage IV emission norms for any high specific power engine. An emissions and performance study was conducted to explore the effects of EGR and multiple injections on particulate, NOx, and BSFC. Recent work has shown that multiple injections are effective at reducing particulate. Thus, it was of interest to examine the possibility of simultaneously reducing particulate and NOx with the combined use of EGR and multiple injections. The tests were conducted on a four cylinder four valve light duty truck engine. Tests were done at emission modes (A, B & C Modes) with EGR are variation along with different injection strategies. The fuel system used was an electronically controlled, common rail injector and supporting hardware. Particulate versus NOx trade-off curves were generated over a range of injection timings for each injection scheme and EGR rate studied. The results show that the combined use of EGR and multiple injections is very effective at simultaneously reducing particulate and NOx. This work was conducted to quantify the EGR rate necessary to reach Bharat Stage IV and above. Injection and atomization characteristics were determined in a high pressure high temperature combustion chamber and emissions and performance tests were conducted in a four cylinder engine. The effectiveness of both, rail pressure and boost pressure, to improve EGR compatibility was assessed.