Science and Education Publishing American Journal of Vehicle Design 1 1 2013 07 31 Investigation in Adjusting the Parameters of a Diesel Engine Converted to Forced Aspiration Gas Engine 9 15 EN Rachid Maamri Department of Mechanical Engineering, Quebec University in Trois Rivi¨¨res, Trois Rivi¨¨res, Canada Fedor Ivanovitsh Abramtshuk Alexandre Nikolaevitsh Kabanov Mekhael Sergeevitsh Lipinsky Yves Dub¨¦ Lotfi Toubal Agbossou Kodjo AJVD2013112 10.12691/ajvd-1-1-2 2013 07 01 2013 07 29 2013 07 31 Many cities and countries today have programs to convert older, polluting diesel transit buses and trucks to run on clean, economical natural gas. Properly implemented, this is an excellent way to quickly reduce fuel costs, clean up the air and reduce noise with minimum capital costs. A poorly executed conversion program, however, can lead to higher exhaust emissions, much higher fuel consumption, unacceptable power losses, poor durability and high maintenance costs. This article gives the results of our investigation of a forced aspiration gas engine 6GCHN13/14 converted from diesel. The mathematical model of the combustion process specified for the gas engine uses a variable Wiebe combustion factor. Use of the developed characteristic maps has shown improvement of engine power indicators in comparison with that of a naturally aspirated engine, as well as a decrease in average operational emissions with the use of adjustable forced aspiration.