The Effect of Valve Gap on Lambda, AFR, and Fuel Consumption Rate of Octane Fuel Series
Jemmy Charles Kewas, Zuldesmi, Hendro M. Sumual, I. P. Tamba, Y. Rampo, H. Dj. Liow

Mechanical Engineering Departement, Faculty of Technique, State University of Manado, Indonesia

Abstract

On a four-stroke motorcycle engine there is a valve mechanism that functions as a regulator of the entry and exit of the air and fuel mixture, and combustion gases. In the valve mechanism there are rocker arm components and valve stems. Over time, the gap between the rocker arm and the valve stem can change due to wear and tear so that it can affect the performance of the motorcycle engine. Therefore, it is necessary to adjust the valve clearance periodically. Often the mechanics adjust the valve gap only based on feeling without measuring the gap with a feeler gauge, for this reason, research is carried out to determine the effect of valve gap variations on fuel consumption and exhaust emissions on 125 cc motorcycle engine.
The research method used is experimental, by testing the effect of valve gap variations of 0.03 mm, 0.05 mm, 0.08 mm and 0.10 mm on fuel consumption and exhaust emissions, which was carried out at a stationary rotation of 2000 RPM for two minutes using octane fuel variant. The results showed that the highest Lambda value is 1.487 occurred at a valve gap of 0.05 mm with Pertamax fuel, and the lowest is 1.304 occurred at a valve gap of 0.08 mm with Pertamax fuel. The highest Air Fuel Ratio (AFR) value is 20.84 gr air/gr fuel on Pertamax fuel with a valve gap of 0.03 mm, while the lowest is 19.14 gr air/gr fuel on Pertamax fuel with a valve gap of 0.08 mm. The most significant fuel consumption is 6.88 mL in Pertamax fuel with a valve gap of 0.08 mm, while the smallest is 5.84 mL in Pertamax fuel with a valve gap of 0.05 mm. So the conclusion of this study is the value of Lambda, AFR, and the Rate of Fuel Consumption have the same trend, there is the most significant value for each fuel occurs at the valve gap of 0.05 mm, while the smallest value occurs at the valve gap of 0.03 mm and 0.08 mm.

Keywords: Valve gap, Lambda, AFR, Fuel consumption

Topic: Optimization Research Based on Local Resources