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Old 03-15-2002, 04:51 PM   #1
Evaider
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Default Question for all you ECU guru's....

Ok, I just thought of this great idea for an ECU and wonder why no one has done this yet. What you can do is write a program for a laptop that will act as a replacement for the ECU. Then you design a cable to attach the computer to the various sensors that the ECU normall attaches to. Ive made quite a few custom cables and programs that interface with various things and I dont think this would be too terribly difficult to do.

The only thing I dont know how to do would be to calibrate the various sensors so that the computer would read them correctly.

The major advantage I see to a method like this is that you would be able to tune your own ECU without special equipment whenever you want and you would be able to store special mappings. IE Race mode, Street Mode etc.

So is this not as simple as I think it is? Or is it actually this simple?
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Old 03-15-2002, 05:18 PM   #2
[ /dev/null ]
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Umm... its not that simple.

First of all, are you a programmer? Have you ever tried to write a program to control an engine? I havent... nor could I any time soon. It would be a monumental programming task in the least.

2nd; you want to run this from a laptop? How are you going to input data from all the sensors and output data/signals to injectors, igntion, relays, etc, etc. You cant run the engine from the parallel port... wont work, sorry.

If you want full control with a laptop, but a stand alone engine management system.

peace
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Old 03-15-2002, 05:25 PM   #3
Evaider
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Quote:
Originally posted by [ /dev/null ]
Umm... its not that simple.

First of all, are you a programmer? Have you ever tried to write a program to control an engine? I havent... nor could I any time soon. It would be a monumental programming task in the least.

2nd; you want to run this from a laptop? How are you going to input data from all the sensors and output data/signals to injectors, igntion, relays, etc, etc. You cant run the engine from the parallel port... wont work, sorry.

If you want full control with a laptop, but a stand alone engine management system.

peace
Yes i am a pretty proficient programmer. And the parallel port is very versatile if you split it down the middle for send and receive you get 12 receive points and 12 send points. Would there be more than 12 of each? If so you could also use the serial port which would give you 4 more of each so you can have 16 send and 16 receive points. And as far as inputting and outputting various sensors and injectors that is what I am asking. I dont think it would be hard to figure some of this stuff out, write a simple program to read raw bits and piggy back that onto the ECU and drive around for a while, then look at the log you have recorded and figure out what is being sent where and when etc etc.

And along with being a very proficient programmer myself, I know quite a few programmers who are extremely good..

Last edited by Evaider; 03-15-2002 at 05:36 PM.
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Old 03-15-2002, 06:01 PM   #4
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http://www.diy-efi.org/diy_efi/members_projects.html

Some material here might be useful to you.

I am presently working on a uC based EBC, have completed a fuel cut lifter design, and in the future will be attempting a MAF sensor remap, but all these are interceptor/piggy back systems. Even for things this simple it is amazing how they snowball and take much longer to do than planned!

The factory ECU is quite sophisticated with quite a lot of resolution that tends to be superior to aftermarket solutions except the very expensive ones, with self diagnosis, and quite advanced knock control from what I hear. Why not just remap that? It is already being done on MY99/00 turbos through the diagnostic port plug in, program, unplug all in a few minutes. I am sure it will be about for the MY01/02 if someone hasn't done it already?

Whilst experimenting with code and mapping you could seriously put your engine at risk just from one tiny error resulting in detonation.

The development costs would be huge.
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Old 03-15-2002, 06:02 PM   #5
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Quote:
So is this not as simple as I think it is? Or is it actually this simple?


If it were this simple, it would be done. if it were this simple, replacement aftermarket ECU's would be much cheaper then a full laptop system.

Personally being in the industry like youself.... I think your not looking at the full picture. We all do this when making proposals on upcoming projects Then a client will tell you, "what if?" or "why not do it this way?" Think of all the reverse engineering you'd have to do to get the appropriate sensor values, electrical circuits designed and made, tuning to just get base maps, UI stuff... The list goes one. The time, money, and repairs that you'd have to go through do not justify doing it your self vs paying $1300 for a standalone.
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Old 03-15-2002, 06:45 PM   #6
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There are a whole bunch of analog inputs that would need to be converted to digital signals for your laptop to deal with. Also the timing is so critical that you would need custom hardware to get things to happen at exactly the right time.

So much custom hardware you might as well build something standalone. And besides.. you're out the cost of the laptop because it's sitting in your car 24/7. Laptops are pretty expensive.
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Old 03-15-2002, 08:31 PM   #7
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I personally would have better luck programming an embedded processor in assembly or embedded C than programming a laptop to do it, but that's what I have experience with. On the other hand, a www.computerboards.com sells reasonably priced I/O cards that are really easy to program and it can be done in VB. But you're not talking about a few hours of running wires and then setting up a quick program and debugging as you go. You could dedicate all your free time to it for months and not finish. I think it comes down to the fact that you have to weigh whether it is worth your time or not. You may be capable of the programming, and you may be capable of the external hardware required for the interface, but the time it would take to do it would be more than I think it would be worth. But that's subjective, I think it's possible, IMO it's just not worth it.

A better idea would be to invest in some already-built electronic controls, like something from HKS for boost, MSD for ignition, etc, and then get something like the AEM controller (if there is one for your car) and program that with a laptop to make minor changes.
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Old 03-15-2002, 08:37 PM   #8
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Quote:
Originally posted by oman
There are a whole bunch of analog inputs that would need to be converted to digital signals for your laptop to deal with. Also the timing is so critical that you would need custom hardware to get things to happen at exactly the right time.

So much custom hardware you might as well build something standalone. And besides.. you're out the cost of the laptop because it's sitting in your car 24/7. Laptops are pretty expensive.
The analog to digital is a very good point, I had not thought about that. Maybe I should work on trying to break the encryption on the existing ecu chip so that it could be reprogrammed on the fly. Anyone got a spare ecu I can have?
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Old 03-15-2002, 08:42 PM   #9
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Quote:
Originally posted by Narcisse91
I personally would have better luck programming an embedded processor in assembly or embedded C than programming a laptop to do it, but that's what I have experience with.
Yeah, I was thinking it would have to be programmed in assembly (which I know people that can) and run under dos so that you wouldnt have the processor overhead that you would have in windows. Also you wouldnt want to have to wait 5 minutes for your computer to boot up so you could start your car. I guess I should move on to the next project. Im determined to make something unique and useful for my wrx, figuring out what thou is the hard part.
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Old 03-15-2002, 08:51 PM   #10
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Would you want your car to be running on Windows? Might redefine the term "crash"
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Old 03-16-2002, 10:20 AM   #11
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Quote:
Originally posted by Evaider


The analog to digital is a very good point, I had not thought about that. Maybe I should work on trying to break the encryption on the existing ecu chip so that it could be reprogrammed on the fly. Anyone got a spare ecu I can have?

The analog to digital would be the EASIEST part. If you don't want to buy an A/D, you can just build one.
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Old 03-16-2002, 11:10 AM   #12
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Quote:
Originally posted by Evaider


The analog to digital is a very good point, I had not thought about that. Maybe I should work on trying to break the encryption on the existing ecu chip so that it could be reprogrammed on the fly. Anyone got a spare ecu I can have?
Yes break the code on the stock ECU, give yourself about a year. Just try to find out what chip #'s it uses...then see if you can find a reader (probably no way Denso is going to release it)...then see if you can get through the data coming and what represents what...then figure out where the maps are, TPS variables, MAF variables, static maps, WOT maps, detonation maps, etc...and the big holy grail of ECU tuning....cold start.

Usually takes a few $million$ in R&D to put together a useful ECU for a production vehicle. Then I've seen (Nissan) the factory revise their code several times over the year to continue "beta testing" the ECU. Then hire a team of programmers and engine tuners to give you meaningful feedback. Oh yeah, and 1/2 dozen test vehicles to go through various environmental conditions....then cross your fingers

Computer controlled cars are an enormous complexity if you think about all the variables, plus the monkey behind the wheel.

I'm not also sure an average consumer computer could respond to interrupts in a quick enough fashion for usefulness. The hardware in ECUs is dedicated and is very fast in what little it does. Oh yeah...what do you do when the computer crashes? If you spend enough money for a ruggedized box (Toshiba has them I think...milspec) to survive a vehicle...may as well have bought some other EMS.

Good, adaptive idea - I wish it could be done this easily.
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Old 03-16-2002, 02:29 PM   #13
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Default Re: Question for all you ECU guru's....

Quote:
Originally posted by Evaider
Ok, I just thought of this great idea for an ECU and wonder why no one has done this yet. What you can do is write a program for a laptop that will act as a replacement for the ECU. Then you design a cable to attach the computer to the various sensors that the ECU normall attaches to. Ive made quite a few custom cables and programs that interface with various things and I dont think this would be too terribly difficult to do.

The only thing I dont know how to do would be to calibrate the various sensors so that the computer would read them correctly.

The major advantage I see to a method like this is that you would be able to tune your own ECU without special equipment whenever you want and you would be able to store special mappings. IE Race mode, Street Mode etc.

So is this not as simple as I think it is? Or is it actually this simple?

Haha...almost sounds like you're talking about an emulator in the DSS hack world.
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Old 03-16-2002, 04:37 PM   #14
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Quote:
Originally posted by Evaider


Yeah, I was thinking it would have to be programmed in assembly (which I know people that can) and run under dos so that you wouldnt have the processor overhead that you would have in windows. Also you wouldnt want to have to wait 5 minutes for your computer to boot up so you could start your car. I guess I should move on to the next project. Im determined to make something unique and useful for my wrx, figuring out what thou is the hard part.
Controling an engine is a realtime control task requiring a deterministic realtime OS or task scheduler. Sorry but neither Dos, Windows or Linux are up to the task, at least not with my engine. Realtime kernels exist that require only 8k of memory and are very fast. C and Forth compilers are available for these so you shouldn't have to program it in assembler (unless you really want to). And yes you would need IO card(s) providing several channels of analog and digital input and ouput.
It would be interesting to know what language the Subaru engineers program the ECUs in.
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Old 03-16-2002, 11:17 PM   #15
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Default Re: Re: Question for all you ECU guru's....

Quote:
Originally posted by tmarcel



Haha...almost sounds like you're talking about an emulator in the DSS hack world.
Hmm. I dont know nothin about those...... cough cough...


Yeah.. thats kinda where I got the idea. And I will just say I have a lot more experience with this than the average Joe that uses it.
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Old 03-17-2002, 12:18 AM   #16
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Engine control is most definitely the task of an embedded system. I design, hardware and software, for embedded systems for a living. If someone were able to characterize the system, the sowtware and the hardware are not very complex. It's characterizing the system that's complex. How exactly do I determine timing at this exact point? Do I have a simple PWM output to each injector or do I need to be able to control slew rates? What does knock look like? These are the questions that have to be answered. There are thousands of them. After you anwswer them all you will find a thousand more.
I don't think the task is so complex that it should take decades and millions of dollars, but I'd be impressed if you released a product with less than 500G invested in R&D.

Good Luck,
Dustin
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Old 03-17-2002, 04:35 AM   #17
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Even just trying to get a fully functional boost controller/AFC going there is an intimate link with hardware setup, software and precise timing, and it is never as simple as one tends to think. And using a microcontroller it is setup for ADC, DAC, PWM, comparators etc, and although the resulting code looks and is simple, it takes a fair bit of fiddling with hardware and software setup to get there. The timing of everything is absolutely critical. But my learning curve is steep because I am an amateur.

Looking at some of the DIY EFI projects it is obvious to me that to say there is a lot to it is a gross understatement. But if you can do it without a whole team of people and retain your sanity and the safety of your engine it would be very impressive.
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Old 03-17-2002, 07:22 PM   #18
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Default Re: Re: Re: Question for all you ECU guru's....

Quote:
Originally posted by Evaider


Hmm. I dont know nothin about those...... cough cough...


Yeah.. thats kinda where I got the idea. And I will just say I have a lot more experience with this than the average Joe that uses it.

Evaider - that's hilarious, what a small world I think I'll have to indulge about this one (look for a PM).
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