Using Road Test for Inspection of an Automotive Engine

Abstract

The engine power could be measured accurately using an engine dynamometer but this process is time and money consuming due to difficulty of coupling the engine to the dynamometer. The coupling process can be eliminated using chassis dynamometer. Hence the chassis dynamometer is a road resistance simulator. Why not to take the actual road as the source of resistance instead of using chassis dynamometer? This process will be faster and cheaper taking less than a minute on road for a single test and will help to detect the condition of the engine and power train easily. The aim of this paper is to evaluate the use of the road as a source of resistance for the calculation of engine power. Nowadays, there are many software products that claim the possibility to measure the engine power on road. In our study road tests have been performed using OBD (On Board Diagnostic System) reader devices and high-speed GPS (Global Positioning System) receiver to measure vehicle speed variation with time during acceleration process. Three different vehicles are used to validate the road tests obtained data using chassis dynamometer. The proposed method proved its ability of using road test during automotive engine inspection process. Based on the validation the OBD and GPS data shows a difference between both methods by ±2% .