Measuring vehicle's powertrain parameters using diagnostics interface

Abstract

This article presents a method of measuring vehicle’s powertrain parameters using a diagnostics interface, performed on a compact passenger car, during real driving conditions, as well as validating them in comparison with mathematical calculations. The parameters of the driving system which can be measured using the diagnostics tool are: the nominal and maximum torque / rotational speed of the Internal Combustion Engine (ICE), ambient temperature, coolant and oil temperature, alternator’s loading, 12V battery’s voltage, fuel consumption, injection timing, vehicle’s speed and acceleration, as well as many other parameters. Based on a few of them, it can be easily determined the instantaneous power produced by the vehicle’s engine, which can be used, for example, for designing hybrid powertrains in a very simple manner, allowing to measure all the values directly via the On Board Diagnostics II (OBD-II) port of the vehicle, in any conditions, on any road, in a real environment, thus eliminating the need of utilizing expensive equipment, such as dynamometers, which can be used just stationary.