NOx Emissions Control for Small Single-cylinder Diesel Engine Using Exhaust Gas Recirculation Strategy

Small Diesel engines pose a very tough challenge of simultaneously meeting NOx and particulate matter (PM) emissions, without hampering performance and fuel consumption. Frequent revision in small diesel engines pose a very tough challenge of simultaneously meeting NOx and PM emissions, without hampering performance and fuel consumption. Frequent revision in emission norms for small diesel engines makes it further difficult, as they need to be upgraded in design and for combustion. These small, low-capacity engines are predominantly used in specific regions/countries where cost plays a major role and hence these engines lack a clear emission reduction strategy. It is required to develop an emission reduction strategy considering available technologies and cost implications. Current research work aims to develop a cost-effective emission reduction strategy by modifying the engine using conventional technologies. The present work is an experimental study of the effect of cylinder head Swirl, static injection timing (SIT), intake valve opening (IVO), and Exhaust gas recirculation (EGR) on a 0.4 l single-cylinder diesel engine's performance and emission. Baseline vehicle has HC+NOx and PM emission levels are 0.61 g/kM and 0.04 g/KM, respectively; which is higher considering existing and upcoming emission norms. The lower Swirl cylinder head,  advanced IVO timings with retarded injection timings shows an 18% reduction in NOx emission with a 3% improvement in performance at the engine dynamometer. Different EGR rates were also studied and effects were analyzed on emission and fuel consumption and emissions. EGR rate of 25% with advanced IVO of 16° with SIT of 5° and 1.9 Swirl cylinder head had shown 48% improvement in HC+NOx emissions, 20% improvement in PM emission, and 11% improvement on CO emissions at the Chassis dynamometer.