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Hello all, I am writing a research paper for a computer science class and have chosen to write about computerized engine management. Does anybody know of good resources for information that can help me do research? I have found some but wanted to ask if anybody has some reputable resources about the history and how the computers used for engine management work (like for fuel, spark, timing, etc.). Thanks (I can wait to finish this paper)!
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I don’t know how to answer this without turning it into a full-blown class/lecture……
But I *DO* want to see what you’ve gotten so far!!!
A quick ‘Google’ search yielded this – http://www.autotap.com/techlibrary/Intr … gement.asp
The whole point of computerized controlled engine management is Emissions, period.
Dreamer, I have to respectfully disagree with you on that last statement. Computers ARE indeed used for Emissions, as you correctly stated. However, that is not the sole purpose of their existence. Your ECT (Engine Coolant Temp Sensor) sends a signal to the PCM that says: “Hey, we’re getting hot here!” So the PCM says: “Ok, let’s close my ground-side switch, and kick on that cooling fan.”
The CKP (CranKshaft Position Sensor) or CMP (CaMshaft Position Sensor) sends a signal to the PCM and says: “Hey, we’ve reached TDCC #1 (Top Dead Center Compression, Cyl #1).” The PCM reads that signal and commands the firing order to begin.
The Up-Stream HO2S (Heated O2 Sensor) sends a signal and says: “Hey, we’re running lean here.” So the PCM commands the Fuel Injector Solenoids to open sooner, further, and/or close later to spray more fuel. This will bring your AFR from say…IDK….15.9:1 as an example, back down to the perfect Stoichiometric AFR of 14.7:1.
The KS (Knock Sensor) says: “Hey, we’ve got some Pre-Ignition going on here.” So the PCM says: “Alright, soccer-mommy here decided to save money by giving us cheap, low-octane bad gas, so let’s Retard our Spark timing a bit.
And of course, the MAF (Mass Air-Flow Sensor) says: “Hey, we’ve got a higher volume of air entering the system here.” The PCM says: “Yup, I’m getting a higher reading from the TPS (Throttle Position Sensor) as well, so the driver wants to go faster. Let’s unlock that TCC (Tq Converter Clutch), Down-shift, and get those Injectors pumping more fuel.
And so on, and so-forth. And of course, as an easy and simple example, let’s say a Rat chews the freakin TPS wires all to h3ll. So the PCM is going to throw a MIL/CEL (Malfunction Indicator Lamp/Check Engine Light), and store a DTC (Diagnostic Trouble Code). Joe Customer tells the Dealership Service Writer: “Damn car has a Check Engine Light, and no Throttle response.
So, the old Tech grabs his (Insert the name of your favorite CAN/OBDII Scanner) and the tool says: “Hey PCM, what’s going on here?” And the PCM says: “I’ve got a P0177 for you.” (DON’T shoot me if I remembered the wrong DTC numbers, you get the idea.)
Tech sees that and says: “Oh, this vehicle has a problem with the TPS. Hmm, let me look at the connection there…..Damn rat chewed through the wires!” So, he solders them up, and takes the keys back to the Service Writer.
SW calls the customer forward and says: “So that’s a standard 1-hour Diagnostic fee, and a (wild guess here) 0.5 hour repair. Labor rate is $100/hr…$150, plus $1.30 for shop supplies/consumables. Now, the Government wants to molest you so that’s $17.83 Sales-tax. Grand total today is $169.13. Will that be Cash, Check, or Credit today, sir?”
Then, the Tech gets paid $20 Flat-Rape, so he takes home a whopping $30 for an hour and a half’s worth of work that (hopefully) took him just 45 minutes to perform.
DISCLAIMER: Clearly, I have not worked in the field (yet) so all times, and monies are *NOT* to be accepted as reality. They are merely S.W.A.G.’s for illustrational purposes only.
Chevypower – The reason we have all those sensors is to control emission output from the vehicles tail pipe, hence why we don’t have carburetors on vehicles anymore due to the regulations set by the EPA. C8-)
Thats why engineers developed computerized control systems to help reduce emission output by our vehicles and maintain the standard set by the EPA.
This is a good read for whenever you have time – http://www.obdii.com/background.html#Where
Yeah, Dreamer’s right on this one. Chevy, why do you think those sensors are telling the ECU/PCM what to do? Ultimately, it’s to make the engine run more efficiently and that reduces a car’s waste (i.e. emissions). I remember driving through LA as a kid and it was like being in a cloud. Absolutely disgusting. You could literally see a wall of smog as you approached the city.
It’s where computers on vehicles are going that is more interesting (and maybe more bothersome) to me. There’s going to be a lot of big brother going on with OBD-III, where the computers will use GPS, dynamometers, gyroscopes, etc. to keep track of your driving habits and they can even be used like cell phones to track your movements. Don’t think that some agency (be it government or commercial) somewhere won’t take advantage of that technology. Also, the idea of self-driving cars bothers me, and of course you’re going to be using computers to do that and it’ll have nothing to do with emission controls. I think that once we get to that point, I’ll be looking into kit cars or something where I can control the level of control (so to speak).
That being said, Ryan, I’d like to see the paper too when you’re done. Post it after you’ve turned it in.
You don’t have to worry about self-driving cars, because that would transfer liability to the manufacturer.
Research: Try Google Scholar for papers on the most recent research on your topic. Narrow your focus to only one part of computer management of automobiles, such as the control network used (i.e. compare CAN vs. FlexRay).
http://en.wikipedia.org/wiki/FlexRay
http://en.wikipedia.org/wiki/Controller_area_network
http://www.iestcfa.org/presentations/wfcs2006/WFCS2006_FlexRay_v2b-1.pdf
some papers are subscriber based ($$$$). PM me if you can’t open it.
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