I would like to learn more about E.C.U's. This relatively tiny piece of equipment carries out so many functions at such high speed I suspect that there might be witchcraft involved. I have an electrical/mechanical background, a rudimentary knowledge of computer architecture , and some experience of working with P.L.C's. Can anybody point me in a direction where I can learn more about them please?
There was a guy trying to map out the differing parameters on a Guzzi, think it was a 15M so he built a simulator to try to split out the differences. Might be of no help whatsoever but an interesting project all the same Marelli 15M ECU - Understanding the correlation between the different parameters John
i suspect you know more than you think. just a series of switches receiving information from various sensors providing an earth to components or relays on a pre programmed map.
Well El Trollo that clearly made you laugh. Whilst a simplistic analogy it is, nether the less it is true. Whilst typical applications for PLC’s are much slower, the processing requirements of an engine isn’t particularly high to the extent that there are PLC’s on the market with a fast enough scan time to do it.
Danger Mouse I believe that EL T found the abbreviations amusing! What I find fascinating is that the ecu is performing so many functions so quickly. I find it hard to visualize a piston thrashing up and down inside a cylinder at 10,000rpm, and even harder to visualize the injectors snapping open and shut with the solenoid operated mechanism, under the control of signals from the ecu. At 10,000rpm the injector is opening and shutting approx 40 times per second to do it's job of squirting a precise amount of fuel . As I understand it, the amount of fuel injected is dependent on the duration that the injector is open. So consequently the longer the injector is open the more fuel is injected. ( please feel free to correct me on this if I'm not correct). So, the ecu is looking at the inputs of many variables, such as throttle position, engine temp, crankshaft speed, air temp, e.t.c, e.tc and determining how long and when to open and shut the injector. I don't understand how such a complex map/programme can be written and stored in an eprom ( is that right?) to take account of the almost infinite amount of variation of all the sensors that are necessary for the ecu to calculate how long and when to open and shut the injector. @Old Jock. Thanks for the link to the Guzzi setup, fascinating stuff!
Yes. Brad writes in a way that is straight forward and easy to understand without gobbledegook and jargon. I discovered his work years ago when I had a carby 900SS and found his reports invaluable when I was l learning how to do a TPS set up on the 4V bikes. He appears on a few of the other forums and sees to be very approachable.
