Emission Reduction Strategies for Small Single Cylinder Diesel Engine using Valve Timing and Swirl Ratio

Document Type: Original Article


1 VIT University, Vellore

2 Vellore Institute of Technology University, Vellore India 632014

3 Powertrain Engineering Department, The Automotive Research Association of India, Pune India, 411038


Small diesel engines are widely used for commercial vehicle and passenger car applications due to higher torque requirements, fuel economy and better thermal efficiency. These engines are exposed to different operating and environmental condition and hence emissions from these engines are erratic. Strategies are required to enhance performance and reduce engine-out emissions considering environmental pollution and regulations. The main objective of this experimental study is to develop strategies for performance improvement and emission reduction for naturally aspirated engines, which can further be used for emission reduction of the multicylinder engine. Experimental Work has been carried out on a single cylinder naturally aspirated diesel engine to study the impact of engine operating parameters like valve timing, swirl ratio and injection pressure on engine performance and emissions. Parameters considered for the study are; three Intake valve opening timings, two Fuel injection pump pressures, two cylinder head Swirls and three Start of injection timings. Results show improvement in performance, lower exhaust gas temperature and reduction of engine-out emission. Exhaust gas temperature is reduced by 5-18% with advanced valve opening and lower cylinder head Swirl option. NOx emission is reduced by 5-50% at advanced IVO options with retarded SOI and lower swirl cylinder head. This has a penalty on CO and HC emissions since the availability of fresh air is less due to higher internal EGR. Higher pressure fuel injection pump helps in improving engine torque with an adverse effect on engine-out NOx emission.