In my last post, I detailed how the relays in the ECU system allow the system to flip to a default engine map. This lets the team keep running, even when something fails, and it decreases the chances of the ECU doing something that blows up the engine. Here’s a short explanation of what exactly an ‘engine map’ is and what it does.
Auto Club Speedway of California
Making New Race Fans, One at a Time
I got a call out of the blue in the office yesterday. A biomedical physicist/radiation oncologist from UC-Irvine who had just gone to his first NASCAR race at Auto Club Speedway had a question about my book, The Physics of NASCAR (which, by the way, you don’t have to be a physicist to read. In fact, it’s probably better if you’re not.) […]
Building Cars
What Next Season’s (Safest) Drivers are Wearing
I finally got to the NASCAR Hall of Fame last week. It was a lot of fun, especially since I was there on a Monday morning and it wasn’t all that crowded. The next day […]
Dean Sicking
An Open Letter to Randy LaJoie: What the Media Hasn’t Said.
It was quite a surprise getting into the car Tuesday and turning the radio to my favorite Sirius NASCAR show. A very distraught Randy LaJoie was explaining that NASCAR was about to announce that they […]
Good basic explanation. The ECU runs in either closed loop or open loop mode. In closed loop it is receiving info from all inputs (sensors) within correct parameters, and so follows the closed loop map.
If some sensors fail, or go outside the normal operational data parameters, such as a temperature, oxygen sensor, or air flow sensor (MAF) the ECU goes into open loop mode, ensuring the engine wont go way too lean or way too rich, for example, but follows a “limp home” mode for ignition timing, and injector pulse width..
There however is nothing it can do if a cam sensor or crank sensor goes bad, it will lose all timing reference for injector PW and ignition spark events and the engine will not run.
And if the TPS,( throttle position sensor) fails completely, the engine will either die or remain at idle only,, depending on the ECU programming.