The Effect of Exhaust Gas Recirculation on Combustion and NOx Emissions in a High-Speed Direct-injection Diesel Engine

A number of tests were conducted on a 2.5 litre, high-speed, direct-injection diesel engine running at various loads and speeds. The aim of the tests was to gain understanding which would lead to more effective use of exhaust gas recirculation (EGR) for controlling exhaust NO_x. In addition to exhaust emission measurements, extensive in-cylinder sampling of combustion gases was carried out using a fast-acting, snatch-sampling valve. The results showed that the effectiveness of EGR in suppressing NO_x was enhanced considerably by intercooling the inlet charge and by cooling the EGR.

A companion paper (SAE 960841) deals with the effects of EGR on soot formation and emission [1].