Mathematical model for four-stroke gasoline engines based on a cylinder-by-cylinder engine modeling method that incorporates physical formulas such as engine geometry and empirical formulas such as combustion duration are applied in this study. In-cylinder pressure and temperature can be calculated for gasoline four-cycle engine. Modeling is done by treating each step in the cylinder as a volume control, solving the conservation equations of energy with submodules for combustion, heat transfer and dynamic analysis. Calculations in cycles are performed at each crank angle, so that the correct angle of ignition, variations in velocity, amount of intake mass and fuel burning speed can be predicted. Adjustment for the combustion parameter such as burn duration and form factor of the Wiebe function to increase the model accuracy was performed. It is shown that the optimization of the Wiebe function parameters able to improve the sum squared error of the engine pressure estimation by 58.17% compared to the result from generalized parameter functions, and the parameter of form factor and burn duration are influential by around twice of (1.86 and 2.55 times, respectively) the efficiency factor.

Currently the use of liquefied petroleum gas is urgently needed as a substituting fuel in both household sector and industrial sector. The Government’s program namely the conversion of kerosene to LPG encouraged people who still use kerosene as a fuel to switch to LPG. There are some public complaints about the quality of the conversion product such as conflagration that occurs frequently caused by the explosion of LPG tube. Application of SNI LPG tube related to the energy conversion program is expected to give a safer condition to the users. This study is conducted by analyzing the quality requirement of LPG tube products according to SNI as well as to identify the fulfillment of LPG tube products.

ABSTRACT

PT. XYZ is a company engaged in manufacturing porcelain

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