Re: ECU Strategies??? Archived Message
Posted by Mike Walker on September 17, 2003, 8:27 am, in reply to "ECU Strategies??? "
Wow what a huge can of worms you have opened here. This one is really worth a discussion forum in it's own right (perhaps not). A few comments for the moment on ECU software strategies - taking one aspect at a time:-
a. Operational/ default strategies. These are designed with a number of conflicting requirements. The safety of the driver or limp-home (or at least get you to the side of the road), protection against engine damage and giving a warning to the driver that he shouldn't ignore the situation. This means some manufacturers program ECUs to 'if in any doubt - turn the fan on' for instance.
b.Diagnostic Strategies. Whether to turn on the MIL light or not , whether to try and 'adapt' to the condition or whether to flag a fault. These decisions may be modified from the engineering ideal by OBD requirements and marketing requirements of observed customer response. Most diagnostic strategies seem to be designed so that the average main-dealer trained chimp (Apologies to the ape family) can plug in a piece of equipment and appear knowlegable to a customer as the prime requirement (i.e. PR/Marketing will always be more important than engineering quality).
c.Adaptive strategies. How many parameters an ECU can 'learn' and what are the learn-cycle requirements. This is often done to reduce the requirements for vehicle servicing but seriously cloud the ability to diagnose the real fault.
d.Running out of space here - good topic though.
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