The Effect of Variations in Spark Plug Electrode Tips on Power and BMEP of Motorcycle Engines

- The purpose of this study is to determine the largest and smallest power values and determine the maximum change in BMEP on the influence of the shape of the spark plug electrode tip on a 150 cc motorcycle engine. This study applies laboratory experiments as a research method with the open full-throttle test method. The increased power test for each spark plug with standard spark plugs yields the highest power of 6.64 kW at 6000 rpm and the lowest power at 2000 rpm of 2.04 kW. While the spherical electrode iridium spark plug produces the lowest power of 2.09 kW at 2000 rpm, the highest power at 6000 rpm of 6.68 kW, and the tapered iridium electrode spark plug produces the highest power among other spark plugs. The highest power is 7.09 kW at 6000 rpm, and the lowest power at 2000 rpm is 2.26 kW. Calculating the average effective pressure (Bmep) results in a pressure change in each spark plug from 2000 rpm to 6000 rpm, but not with a spherical electrode iridium spark plug; only 2500 rpm does not change. The calculation results in standard spark plugs with the lowest bmep value at 2500 rpm of 619 Kpa and the highest of 725.33 Kpa, while the tapered spark plug of the iridium electrode produces the lowest bmep of 606.34 Kpa at 2500 rpm and the highest of 749.78 Kpa at 6000 rpm. The tapered electrode iridium spark plug produces the highest bmep of any other spark plug, with the lowest bmep value of 670.61 Kpa at 3000 rpm and the highest of 774.23 Kpa at 6000 rpm.