The purposes of the research were to create and efficiency validation of computer assisted for the courses of practiced disassembly and assembly fuel injection nozzles of Diesel Engine based standard 90/90 and analyse the learning achievement of the student after by using computer assisted instruction. The subjects in the study were 11 second year diploma students enrolled in Mechanical Power Department Rajamangala University of Technology Phra Nakhon. The Researcher using the experiment by let the students do until test before class and then stUdy by using computer assisted instruction focused on practiced disassembly and assembly fuel injection nozzles of Diesel Engine. After that let students do the unit test again at the class and calculate to find out the efficiency of the computer assisted instruction and analyse the learning achievement of students after study. The research result revealed that the efficiency of the computer assisted instruction was efficient in standard 90/90. Moreover after learning achievement at significant level of 0.01.

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.