Advanced Automotive Diagnostic Systems at Volvo Technology
IQPC: The automotive industry has witnessed an ongoing increase in electronic components. What does that imply for fault tracing?
Henrik Hagstr÷m: Increased number of components in combination with more distributed systems makes it more difficult for a workshop mechanic or technicians to fault trace a system without having knowledge of system design and correlations between different sensors and actuators. This means that it is more complex functionality and hard to judge if it’s normal functional behavior or a certain failure mode. This means that that product development organization also needs to design for diagnostics and fault tracing in an even more informative way and maybe support the mechanics with tools like guided diagnostics.
IQPC: What are the major challenges for introducing model-based diagnosis? Can you give an example?
H.H.: Developing models takes time and might be hard to motivate during a specific project, but in long term it will take less time to maintain and update a model instead of written specifications.
There are also challenges how to translate the system into a model, what level of details etc.
But for the next project, some models can be re-used and will then take less time to develop. Most challenges are process related and need to fit into the current process.
But with this in place, the diagnostic quality will probably be better and you will also get help during system design and development.
IQPC: Where do you see room to improve both reliability and cost-efficiency of diagnostic systems?
H.H.: Usually diagnostics needs to be balanced between either reliability (high level of fault detection), or increased product cost. When doing this balancing it must also be decided what to detect onboard the vehicle and what to take help of the off-board tool. When considering this, there must also be some judgments around severity and probability of the specific failure? How complex will the fault tracing be? How long time will it take to find the actual fault?
With Model Based Diagnostics it is possible to make conclusions early in projects and analyze the diagnostic quality for the system based on fault tracing possibilities. By that it is easier to argue for better hardware support for fault detection and see if more fault codes are necessary to be implemented. In some cases it is better to have a low product cost but then take help of an off-board tool instead.
IQPC: Diagnosis affects the whole vehicle lifecycle. How will model-based solutions change Development, Production and After Sales?
H.H.: By utilizing Model Based Diagnostics during product development, it will be easier to develop the diagnostics in an early phase when there are possibilities to change or adjust the product design depending on the fault detection and fault tracing capabilities. The model information will also assist in creation of verification requirements and test cases to secure complete vehicle functionality when it comes to fault detection and failure information. With help of the models it is also possible to generate information for system FMEA.
When it comes to Production, it is possible to take help of the models if there are unknown problems and by that, be able to pinpoint possible areas where the problem is present.
For After Sales the models can be utilized for fault tracing purpose either by some guided diagnostics that is implemented from the exported decision trees or by simulation of the models.
IQPC: Which of today’s trends and developments will shape the future of automotive diagnosis? What will diagnostic systems look like in five years?
H.H.: An important area for the future will be better precision in fault detection for the onboard diagnostics. This can be solved by either designing new products with additional hardware or by implementing additional software functionality for system monitoring. There will probably also be more software support for system monitoring for being able to detect trends in system data and component signals and by that, be possible to predict a break-down before it really occurs and causing a problem for the customer. Remote fault tracing will also be of interest to provide information to back-office support for better assistance if a vehicle is having a problem.