Faster and more efficient: new processes for on-board diagnostics system
The on-board diagnostics system detects whether the emissions-related systems in the vehicle are working properly. Compliance with legal requirements is checked before the start of production and later verified during ongoing series production. In the process, Porsche Engineering increases efficiency with testing and simulation tools developed in-house.
On-board diagnostics (OBD) monitors the functionality of exhaust-related components over the life of the vehicle. If an electronic control unit (ECU) returns implausible feedback, a corresponding code is stored in the OBD error memory of the ECU—for example if AFR sensor no longer correctly detects the oxygen content in the exhaust gas and the engine control unit then changes the combustion parameters.
Two years later, stricter emissions limits led to the more powerful OBD II system still in use today, which monitors emissions more precisely, includes other components in the check, and offers more detailed diagnostic options for workshops.
Coordination with certification authorities
To this end, Porsche AG coordinates test series with the certification authorities in the individual regions around the world, which the experts in Porsche Engineering’s testing department then work their way through. Unlike in the rest of the world, a positive test report will then no longer be sufficient in China to certify a new vehicle model. Rather, the OBD test must be carried out on site and under the supervision of the authorities, explains Dr. Sebastian Rüger, who is responsible for OBD certification at Porsche AG, among other roles.
As Porsche China’s exclusive strategic partner, Porsche Engineering supports on-site certification by providing technical services such as conducting the test series. Porsche AG is responsible for coordinating the test results with the respective certification authorities. Thanks to close cooperative relationships and continuous exchange of information between the colleagues of Porsche Engineering in China and Germany as well as Porsche AG, we are able to implement the approval of the vehicle model on a tight timeframe in the process, says Rauner.
Simulation of errors
Instead of installing and removing defective components for test bench examinations or road tests at great expense, we modify the respective sensor signals or messages in the vehicle’s electronic data system, explains Bach. This requires an in-depth understanding of the component and its function in the overall system, which Porsche Engineering, as an OBD service provider from the very beginning, has gained in countless development projects. Our strength is our expertise in the areas of complete vehicles and testing. On this basis, we have developed our own testing and simulation tools, which can be used to reproduce around 95 percent of the defects in the OBD system, explains Bach.
For example, the function of the throttle valve actuator is simulated externally during engine operation, so the throttle valve installed in the vehicle can be tested separately. When it comes to simulating networking faults in the electronics architecture, we are always up to date thanks to our strong cooperation with colleagues in development and can therefore present the appropriate test procedure as soon as new diagnostic functions are introduced, says Bach.
Info Text: Richard Backhaus
Nov 20, 2021 at 09:22