NOISE AND TAIL PIPE EMISSION OF AFTERMARKET CONVERSION GASOLINE VEHICLE TO CNG OPERATION

Currently, in most countries, the converting gasoline vehicles to run on natural gas usually occurs aftermarket, without any modifications in its vehicle engines. This will continue to exist for a long time, thus the question of noise and exhaust emission of these vehicles over their useful life become very important. This paper presents the experimental results carried out on aftermarket conversion gasoline vehicle to CNG operation, to evaluate aftermarket conversion, from standpoint of noise and exhaust emission. However, a series of road tests were done under steady state condition, over 10000 km of converted vehicle life. The investigation was performed over a wide range of vehicle speeds and loads speed range started from 20 until 100 km/hr, with variation 20 and load range started from one passenger until 4 with Variation one. The noise was measured at the driver head position and exhaust emission at exhaust manifold. The results are compared between the two fuels, CNG and gasoline. The CNG fueled engine showed low emissions of reactive hydrocarbons and noise, but NOx emissions showed an increase in their amounts.