Open-source engine tuning hardware development

[phrozen]

I'm starting this thread to get input from the srt-4 community.

I am going to develop my own engine tuning controller. This will most likely start as a piggy-back system to allow minor tweaks of the ECU operation. It may develop into a complete stand-alone system as the hardware and software matures. However, for right now it will just have lots of inputs and outputs to "tweak" signals just a bit to fine tune the engine without sacrificing drivability.

This isn't going to be a product. It is mainly for my own use. I will publish all my schematics, board layouts and software, so you're all free to use it at will, but it will require some programming ability and some hardware knowledge.

I realize things like this exist already, namely VEMS and megasquirt, but they just didn't suit what I wanted.

Here's the thread that started my ideas flowing, if you want background:
http://www.srtforums.com/forums/show....php?p=2033863

Ok. Lets get down to business. I'd like some input on what the architecture should be.

To begin, I will base the first rev of the circuits around this Motorola demo board just to make initial development easier.
http://www.freescale.com/webapp/sps/...de=DEMO56F8013

Here are pictures of the demo board.
http://www.geocities.com/phrozenphre...img_3154sm.jpg
http://www.geocities.com/phrozenphre...img_3155sm.jpg
http://www.geocities.com/phrozenphre...img_3156sm.jpg
http://www.geocities.com/phrozenphre...img_3157sm.jpg

To develop code for it you will need:
http://www.metrowerks.com/MW/downloa...=Hybrid56800v7

Get Codewarrior v7.0 for the 56800/E. They will also send you an 8k special edition license. That will should be enough for us, given the processor only has 8k words of program FLASH.

Then get the 7.2 upgrade, here:
ftp://ftp.metrowerks.com/pub/updates...7.2_Update.exe

Then you will need an updated license file. Let me know when you're ready for it. I'll PM it to you. I had to work with their support team to get the correct 8k license for 7.2.



In later revs I will add the DSP directly to my own design, reducing the processor cost from $65 to $3.

Now, inputs and outputs. What will we need? I'm going to try and design for lots of future uses, but I will only start by using a few of these at a time. So, just because it is on this list doesn't mean you'll have to use it.

• PWM Outputs @ 12 volts (6 available)
• 4 fuel injectors
• W/I pump or HSV (see aquamist) or other variable speed motor drive
• Ignition coil - 2 outputs
  
  General Purpose 12 volt outputs
• Boost solenoid
  
  12 volt PWM inputs
• measuring the stock ECU fuel injector drivers
• ignition coil drive signal - 2 inputs
  
  General purpose 12 volt inputs
• Solenoid drive
  
  Analog inputs, 0-5 V range (For measuring / intercepting analog sensors)
• stock sensors like MAP, TIP, TPS
• aftermarket sensors like wideband O2, EGT probe, W/I flow meter (self-tuning!)
  
  Analog outputs, 0-5 V range (For outputing "modified" sensor outputs)
• MAP, TIP, TPS
  
  5V digital inputs
• wheel speed sensors
• crank position sensor
• A few button inputs for real-time user adjustments.
  
  5V digital ouputs
• Driving LEDs, what else?
  
  Serial port
• laptop connection
• GPS input (I've got some ideas for that one)
• OBD scanning for extra sensor information
  
  Other connections
• LCD driver for real time displays
• Secure Digital or MMC card interface for data logging
  

Ok. Let me know what you think. I'll update this post to include schematics as I create them.

New! Parts List for Design

• DACs - MAX534 (8-bit, 4 outputs) or AD5318 (10-bit) or AD5328 (12-bit) (both 8 outputs)
• A2Ds - TLC2543 (12-bit, 11 inputs)
• LCD - CFAG12864B-TMI-V http://www.crystalfontz.com/products...CFAG12864BTMIV
• SPI to Parallel Convertors for LCD - 74HCT595
• Parallel to SPI convertor for extra digital inputs - ?? HCT-something!
• RS-422 bus driver - sn75c1167 - use to drive SPI bus over cat 5 for remote LCD, Data card slot, User input device....

Block Diagram Version 1.0
http://geocities.com/phrozenphreak20...agram_v1_0.gif


Digital Design Summary:
On the main board there will be:
14 High Speed Digital I/Os (half inputs, half outputs)
16 Low-speed Digital I/Os (half inputs, half outputs)
11 Analog inputs
8 Analog outputs
2 Serial Ports

On the Remote Data unit there will be:
8 Digital Inputs (buttons, switches, etc)
8 Digital Outputs (LEDs, etc)
LCD
SD / MMC Interface

[sour kraut]

Just posted on the other thread. You sound like you know what you're getting yourself into. Good luck with it man!

[sour kraut]

Quote: Originally Posted by phrozen

-6 PWM outputs @ 12 volts (4 fuel injectors, W/I pump or HSV, etc)

-Four injectors
-boost selenoid
-water injection(if you can find a fast enough selenoid)

Quote: Originally Posted by phrozen

-6 12 volt PWM inputs for measuring the duty cycle of ECU outputs (measuring the stock ECU fuel injector drivers, for example)

-Four injectors
-one of the two trigger wires on the coil(for rpms)
-boost selenoid

Quote: Originally Posted by phrozen

-8 Analog inputs, 0-5 V range. For measuring / intercepting analog sensors, such as the MAP, TIP, and TPS. Also for connecting things like a wideband O2 and EGT probe.

-You have five good readings sensors above
-water injection nozzle clog
-intake temp
-knock sensor

Quote: Originally Posted by phrozen

-8 analog outputs, 0-5 V range. For outputing "modified" sensor outputs. Think of this as a completely adjustable MAP clamp. You can create any clamping curve you like...

-Nothing else I can think of to use a 5volt out for.

Quote: Originally Posted by phrozen

-Some number of 5V digital inputs for sensors like the wheel speed sensors, crank position sensors (I'm assuming they output 5V logic pulses)

-sounds good, the wheel triggers combined with the rpms can be used to calculate the gear you are in, thus gear specific boost levels.
-crank sensor is a little trickier, we use a messed up tooth count. It can be done though.

Quote: Originally Posted by phrozen

-Some number of 5V digital ouputs
-Serial port for laptop connection or GPS input (I've got some ideas for that one)

- creating maps for boost and injector pulses( or make it self tune giving a specific a/f target.

Quote: Originally Posted by phrozen

-LCD driver for real time displays...

-A kick ass scrolling display of certain inputs across from the odometer display in the gauge cluster!

Quote: Originally Posted by phrozen

-A few button inputs for real-time adjustments.

-switching between stock and predefined boost/fuel maps, 2 stage rev limiter,yada yada yada

Quote: Originally Posted by phrozen

Ok. Let me know what you think. I'll update this post to include schematics as I create them.

Thanks!

I'm already drooling at the thought of it!!

[DSrt]

First I don't know jack diddly about embedded processors .. but I am willing to help out where I can. I do alot of programming of various control systems utilizing PLC components. C and VB are hobbies. I know they are different worlds.

It seems to me that another alternative you could use to do this is to somehow read the program from the existing ECU and then reverse engineer it. It shouldn't be too difficult to figure out what inputs go where and what lookup tables are used. Then you could just adjust the lookup tables to adjust the exisiting PWM for instance. I imagine it operates on some type of linear curve probably between multiple setpoints to determine the various engine parameters. It may operate on some other formula but I would think it would be easier for DC to develop if they had some fixed points to reference for barometric pressure, boost, temperature etc.

Is this too much or perhaps the wrong path ya think? It would make it more difficult to integrate additional functions such as whatever you have in mind for the GPS (altitude readings?). But if the exisintg CPU is doing all the work already why not let it and just tweak it? This is the reason I have not gone in for a piggy back control of any kind yet. I am waiting for an integrated stand alone system because I think piggy backs introduce alot of potential issues.

ne hows .. my $.02 .. If I can do ne thing to help holler.

[sour kraut]

People on here have been trying to reverse engineer this pcm since day one. I think it would be easier to just admit mother mopar got us good on this one and try to find away around it that makes the computer happy.

[phrozen]

Ok. Some good ideas. A few things I probably can't do.

Probably can't change the rev limiter without creating my own ignition control. If the stock ECU stops giving me ignition pulses, I'll be at a loss for what to drive the ignition with.

Also, driving the LCD in the stock gauge cluster would require a lot of hacking of wiring and isn't worth it for such a small display. I'm talking about adding some small extra graphical display, perhaps next to the boost gauge.

The crank sensor shouldn't be too hard. As long is it gives some constant number of pulses per rotation... All you have to do is count them once and enter it as a constant.

The GPS input is to make a self-calibrating G-meter. That would take a whole new post to explain that idea. Basically, use GPS and the ABS rear-wheel speed sensors to very accurately determine the tire diameter while driving normally. Then with the calibration, you can use the very accurate wheel rear diameter and position measurement to calculate acceleration. The rest falls out easily. 1/4 mile timer, 0-60, torque (after putting in the car weight).

You just can't use the front wheels for this. Well, for obvious reasons.

[FastAttack]

Quote: Originally Posted by Sour Kraut

People on here have been trying to reverse engineer this pcm since day one. I think it would be easier to just admit mother mopar got us good on this one and try to find away around it that makes the computer happy.

yes its called lawyers on your ass if you release any info if you cracked the code..

If I was an ECU hacker.. I wouldn't even touch the SRT-4 ECU unless it was for personal use only with no sharing with friends