Modelling and simulation tools to calibrate an engine management on board diagnostic system

Over the past decade, there has been a dramatic increase in the amount of electronic hardware applied to the control of automotive engines. The increase in usage of electronic engine control can be attributed mainly to the increasing pressure on vehicle manufacturers to reduce the tailpipe emissions of hydrocarbons (HC), carbon monoxide (GO) and nitric oxides (NOx). A degree of control over exhaust emissions can be achieved through the use of advanced electronic hardware/software, as part of an integrated engine management system (EMS), and such an approach offers greater flexibility and closer control than traditional mechanical devices. The paper describes the application of modelling and simulation methods to aid engine management calibration and, in particular, calibration of on-board diagnostic (OBD) systems. Two case studies are presented. The first is focussed on the calibration of an airflow meter and manifold pressure sensor of a 4.0 litre V8 engine. The second describes some aspects of a hardware in the loop (HIL) facility, and its use to perform a number of EMS diagnostic checks as defined by legislation. The objective is to make use of a HIL system to verify that EMS diagnostic software meets specified requirements. In both case studies, modelling tools have allowed accurate diagnostic checks to be developed and tested