Effect of piston geometry design and spark plug position on the engine performance and emission characteristics

This paper investigates the influence of piston geometry design and spark plug position on the engine performance and emission characteristics at a range of speeds from 1200 rpm to 2200 rpm. Accordingly, the parameters of the indentation depth, the spark plug position, the location of the recess, and the engine's compression ratio are changed and evaluated. The concave center depth improved the mixture of air and fuel, increased power, and reduced fuel consumption. The power can be improved by up to 3% when the piston top recess is 25 mm. In addition, within a limited range, the combustion process and the engine's power and emission characteristics are enhanced when the engine's compression ratio rises. Increasing the depth of the depression on the top of the piston improves fluid flow in the cylinder, resulting in increased power, fuel efficiency, and emissions; however, the improvement between the indentations remains unclear.