"Effect of Fuel Injection Pulse and Dwell Period in Split Injections on the Performance and Emissions of a Diesel Engine"

Abstract

The diesel-fuelled engines are fuel efficient but are prone to high levels of NOx and soot emission. It has become easier to have precise control over fuel injection parameters with electronics-embedded diesel engine components mostly available on the common rail injection system of multi-cylinder engines. In the present competitive market, to utilize and continue the usage of diesel-fuelled engines efficiently, an attempt has been made with an in-house developed computational code to employ a split or multiple injection strategies for a direct injection single-cylinder diesel engine to obtain lower harmful emissions with appreciable engine performance. A quasi-dimensional model involving the engine parameters; equivalence ratio, injection timing, exhaust gas recirculation, pilot injection timing and its quantity. In addition, injection pulses with two different dwell periods are considered. The capabilities of the quasi-dimensional model have been verified and the trends are observed to be in line with the literature. The results of numerical experiments considering split injections with a variation of fuel quantities in the first pulse [10% -75%] with two dwell periods [8•CA and 3•CA] in conjunction with moderate boost pressures [10% to 30%] resulted in effective NOx-soot-piston work trade-off. Injection strategies with lower pilot quantity and larger dwell have resulted in lower NOx emissions and larger pilot quantity with retarded main injection timing has effectively addressed perennial NOx-soot trade-offs and would effectively address stringent emission norms.