Combustion and Exhaust Emission Improvement in a 3-Cylinder Mpfi Engine Through Downsizing

This research aims to compare the potential and existing conditions of a small-sized spark ignition (SI) engine with a 1.0-liter capacity suitable for cylinder deactivation. The cylinder deactivation strategy is used to solve the issues of inefficient combustion and increased exhaust emission under part loading. Consequently, the possibility of implementing cylinder deactivation in terms of decreased exhaust pollution has been assessed. A computerized, 1.0-liter, 4-stroke, water-cooled, spark-ignition engine with an open engine control unit (ECU) and multi-point fuel injection (MPFI) was used for the trials. Both modes were tested at 2500 revolutions per minute (RPM) under loads of 15, 30, and 45 N-m. The spark plug and fuel injector deactivate the cylinder. The results show that when the highest possible load is used, the peak cylinder pressure is 55.78% higher, and the maximum heat release rate is 53.96% more in the deactivation mode than in the traditional mode. In deactivation mode, the mass fraction consumed is larger at each crank angle point, suggesting a faster rate of combustion and increased combustion efficiency. The increased mean gas temperature permits the catalytic converter to perform more efficiently after downsizing. When compared to the conventional mode, carbon monoxide (CO) emission is almost non-existent at full load, unburned hydrocarbon (UHC) is reduced by 92.89%, and oxides of nitrogen (NOx) are reduced by 35% in the deactivation mode. Furthermore, the experiment indicated that, when employed at part load, the deactivation mode is more beneficial than the standard mode in terms of better combustion stability and lesser emissions.