Methanol injection

Projects General Guidance
1

So I am trying to build a better control system for methanol injection. My first step is motor control.

I purchased an off the shelf motor controller that could handle the 10 amps that i needed. The one I grabbed was a MXA033 from MAXX Tronic. It was cheap and it meant I didn't have to make a shitty soldered up radio shack board that I was unsure would work. I am new to this stuff. The controller is rated for 15 amps so I am not worried about it not holding up.

I tested the board and notices that the control voltage to the IC1/2 was a range of 4.45v for 0 percent output and 0v for 100%. Here is the question. I am using an old arduino board to control it. I am not 100% on the best approach but this is what I think would work based on my limited knowledge of discrete components. Keep in mind I am a college dropout with no formal electronics training other than 10th grade physics. I am just throwing this out there.

If i remove the pot from the board and place a 10k ohm resistor between the legs from r5 and pin 3 of IC1/2. this would pull up the voltage to 4.45vdc.
Then if I place a npn transistor from the r6 connection to the pin 3 of the IC1/2 and use a pwm pin of the arduino with a pull down resistor on the output from the arduino I should be able to control the output of the motor controller using the 0-100% output of the pwm on the arduino.

Does this hold any water? Please do not pick apart my method. I was just trying to modular-ize and make this easy. I was going to mount all this in an aluminum box and make it easy to repair since it will be my first real project with an arduino.

IMG_0206[1].JPG

2

Do I need to have an opto-isolator?

3

And I suppose I need a capacitor to smooth out the pwm of the arduino. What a mess. Wouldnt it be easier to just use the native pwm to a mosfet or is that not as simple as it is?

4

Could you expand on that? Is this to be an independent standalone fuel injection system for an engine running on methanol, or an add-on to add a second fuel to a petrol engine, or what? What sort of injectors are you planning to use? What sensors and control logic?

5

First off this is going to be a water/methanol injection system for my 2006 LBZ Duramax Diesel. Currently I use EFI Live to modify the engine tune and transmission shift logic. I plan on creating a map within EFI live to use the old EGR control outputs to give a signal of 0-100% to arduino. I am leaning towards this method because there is the ability to also change the injection timing and pulse width based on current egr function (really going to be methanol function). I then would use a spare input to tell the ECU what the input rate is. This would then allow the truck to fall back to a standard mapping without injection. The whole goal of the system is to improve fuel economy and towing performance.

I am using the standard pump controlled injection method. I have a 1gpm devilsown pump, 2 mcmaster carr fogger nozzles, 2 solenoids, tank low level switch, motor speed controller, tank etc.

The arduino will be mapped to stage the nozzles and pump speed to allow me to flow the appropriate amount of water/methanol.

My first step was to control the pump so I can figure out the mapping. I was going to use the off-the-shelf pump controller becasue I have never tried to motor control and was unsure about frequency and such and I also never found a shield to allow me to control a motor that pulls 10amps.

I was looking at the motor control board the other night and I think I am just going to pull the IC and directly drive the transistors connected to the the IC pwm output for now. Then I can elaborate on it later. I have no way of building a decent board so this was the easy way for me to prototype.

I guess I posted a little early in the game. IT seems that nobody really wants to touch the subject. I don't know why?

6

I think I get the general idea. I'm doing something similar, but in my case it's in a supercharged petrol engine with MegaSquirt. I just used an extra fuel map and injector driver circuit, and my WI controller does pressure/flow monitoring to give a healthy/unhealthy signal to the ECU to switch the ECU between aggressive and conservative maps.

I don't know what form the EGR control output takes, but if it's an analog control then using an Arduino to convert that to PWM seems reasonable. The Motors/Mechanics/Power section of the forum is the place to go for advice on switching those currents. I think it's more than you could expect any normal shield or protoboard to cope with and you will probably need to design your own circuit. You might consider just bolting the transistors to a heat sink and using discrete wires to connect these to your vehicle wiring connectors and the Arduino signal/ground, rather than trying to use a PCB. In electronic terms the circuit is relatively simple and probably doesn't warrant the cost and hassle of buying motor shields and trying to adapt them.

7

I agree. I think I will be going a different direction with the case and such. I wish I new of a good supplier of decent aluminum enclosures. I looked on the internet but always find ones that look like shit. I think I am going to try and find something like the one my old megasquirt came in.

8

I wish I new of a good supplier of decent aluminum enclosures.

There was a guy in Products and Services making aluminum cases:
http://arduino.cc/forum/index.php/topic,130588.0.html

Custom doesn't seem to be a problem. It couldn't hurt to contact him.

9

Oddly enough I forgot my buddy at work has a stockpile of old school car amps. I will be taking on of them and modifying the case. IT is perfect since it is already setup for transistor cooling banks. I just have to be creative.

10

Hello,

I m wondering if you can share the Arduino code because I want to do the same on my car.
I have another code found on internet for a boost controller, I can share it with you if you need it. I wish somehow to combine these 2 codes in one app with a small graphical interface (if I find someone with Arduino experience to do it for me)
I ve ordered a Arduino Mega and a 2.4 touch screen , it would be so awesome to have the water injection, boost controller and live data for boost, air intake temp, cooling fluid temp and EGT on that tiny screen.
I was tinking to put a RACE mode and a ECONOMY mode buttons to make things easy.

11

Don't revive a 6 year old thread. Start your own. Make a link back to this one to let us know what you've already read. The originator definitely won't be getting any notifications that you've posted in his thread.