According to the research entitled “the innovative engine prototype powered by diesel and LPG as fuel for agricultural” in 2019 the problems found while using the engine were as follows: the accumulated heat in the auxiliary combustion chamber reached 300 C in case of gasoline engine use and a lot of black smoke in the exhaust was found at the speed higher than 1800 rpm in case of a diesel engine use. In order to extend the research and solve two foresaid problems the objectives of this study were 1) to develop an auxiliary combustion chamber for cooling 2) to develop a scalable gas-air mixing device and 3) to compare diesel and LPG consumption rates by modifying a small diesel engine Yanmar version TF120DI to install LPG fuel systems and ignition system. In addition a gas-air mixing device was modified while an auxiliary combustion chamber was developed to reduce the compression ratio to the same level as the gasoline engine for replacing the position of the original diesel fuel injector. This method could support LPG fueling only whose function was characterized by the function of a gasoline engine. The auxiliary combustion chamber could be removed and then installed a diesel injector to return using diesel fuel. From an experiment to compare the modified engine operating as a gasoline engine it was found that the temperature of the auxiliary combustion chamber and the temperature of the engine cylinder head of Honda GX160 were measured at the maximum speed of 182 C and 186 C respectively. It was found that carbon monoxide content was 0.41 % and 1315 ppm hydrocarbons. When used as a diesel engine it was found that the black smoke was exhausted at 1.5 % which was similar to the diesel engine before the modification. From the experiment of using the power engine for pumping water with an Irrigation propeller pump with the diameter of 8 inch at a constant engine speed of 1000 rpm it was found that the average diesel usage was 0.65 kg/hr or about 0.77 L/hr with the cost of 21.00 Baht/hr and if using LPG as fuel the average LPG consumption was 0.57 kg/hr with the cost of 13.71 Baht/hr which could save up to 34.71 % of costs.

Presently the rail transit system plays a major role in the commercial world that they currently use diesel engine not only causing to a lot of fuel consumption but also generating numerously pollution. Therefore this project aims to study the break-even point of investment under comparison of brake specific fuel consumption and pollution of locomotive engines. By experimental works there are 3 types of locomotive engine: Pielstick M.T.U. and Caterpillar which are the difference of the combustion chamber and the fuel injection systems. The simulation load on the static tests (Dynamometer) was used following the regulation characteristic curve which is standard of State Railway of Thailand. As a result of testing the engine using common rail type of fuel injection system M.T.U. was the lowest brake specific fuel consumption at all of engine by the average of all engine speed 206 g/kW-h of brake specific fuel consumption. It is lower than Caterpillar (Semi common rail with direct injection) which is 314 g/kW-h equivalent 34.39 % while Pielstick engine a mechanism fuel injection system is 389 g/kW-h equivalent 47.04 % For pollution area there are Hydrocarbon (HC) Nitrogen Oxide (NOX) and black smut. The engine with direct injection system relieved the previous substance less than the pre-combustion engine. Moreover the compound of carbon monoxide (CO) was found that the pre-combustion engine (Pielstick) discharged carbon monoxide (CO) less than the direct injection engine (Caterpillar) whereas the common rail engine emancipated same substan cenear by with the pre-combustion engine (Pielstick). However the new technology of the engines is high maintenance costs. Therefore a number of applications have to be needed to make a quantitative value for the investment.