In today's state of the art vehicle drive trains, there is hardly any major component that is not controlled or monitored electronically. Especially the complex modern combustion have a wide variety of parameters like injection, ignition, variable valve timing, variable port geometry, EGR etc. This variability allows unprecedented performance, fuel consumption, emission levels and driveability, but requires a tremendous effort for calibration of the ECU.
Modern test bed technology, DOE, design of experiments, and powerful calibration software are required to handle the increased number of test runs which are necessary to for calibration of such a complex, modern combustion engine system. However, high dynamic engine test beds, drive train test beds, or the simulation of climatic conditions increase testing costs, and after all, even the most sophisticated technologies can't reproduce the complexity of a complete vehicle and real driving conditions.
Therefore, taking measurements in the vehicle in addition to best bed measurements, provides a potentially cost and time saving alternative, with the advantage of absolutely realistic measurement conditions, but at the expense of reproducibility of measurement runs. It has proven to improve the quality and reliability of the engine application, control systems and components in the vehicle, and according to a major car manufacturer, was for example crucial for bringing SULEV vehicles into production.
Using combustion diagnosis systems in combination with an ECU application system to measure data in correlation to the combustion cycles has opened new insight into the processes and the interrelations between ECU, injection system, combustion system, exhaust system, engine mechanics, on-board electronics and other parts of the vehicle.
The detailed information about every single combustion and its parameters enables application and development engineers to optimize the vehicle performance under all conditions. It helps to identify and consequently correct ECU function errors, to optimize the strategies for emission reduction, and to improve the responsiveness and driveability of the vehicle. Additionally, these aspects of vehicle quality can be verified and tested under all climatic conditions or sea levels.
This paper will take a look at the measurement system that can be used for such measurements, and the type of data which can be acquired. It will discuss some examples of improvements in engine calibration, emissions, performance and engine hardware. It will show how the in-vehicle measurement approach ideally supplements testbed testing to reach emission limits, and to improve and fine tune engine performance and driveability while keeping costs under control.