I have a challenge for all the electronics gurus out there. I am currently running my MS3/3X on a basically stock 97 2.0L VW 8V motor code ABA. Well all pre-Drive by Wire OBD2 VWs and Audis use a throttle body with built in idle control. I have it _sort of_ working with PWM warm up control but closed loop is out of the question. After doing a bunch of research and testing I have come to the conclusion that the idle motor in the throttle is actually a bi-directional DC motor.
Sooooooo....... can anybody out there come up with a practical way to properly control this d*** thing? It does have a second TPS built in for position dectection and I could provide a factory ECU and throttle for reverse engineering purposes, but this is way beyond my skill set.
Jeff
A challenge for the electronics gurus
Moderators: jsmcortina, muythaibxr
A challenge for the electronics gurus
Linfert Performance/321 Motorsports
SCCA 2019 SM National Champion Crew Chief
SCCA 2023 FP National Champion Tuner/electrical engineer
100s of MS systems built installed and tuned
Support the developers!
SCCA 2019 SM National Champion Crew Chief
SCCA 2023 FP National Champion Tuner/electrical engineer
100s of MS systems built installed and tuned
Support the developers!
Re: A challenge for the electronics gurus
Doing that right would not be easy - it would require a combination of custom hardware and firmware changes.
Hardware-wise, you'd need what's called an "H-bridge driver" to feed the motor. That driver would basically have two signal inputs: one to increase the throttle position and the other to decrease it. You might be able to use something like this: https://www.sparkfun.com/products/9670 although it's only rated 2 amps which I'm not sure would be enough. The inputs on that module would have to be connected to two outputs on the Megasquirt.
Then, the firmware would have to be modified to send the appropriate signals to the module at the right times. That's the fun part! Although it might not be that hard, there are probably "increase" and "decrease" hooks in there already due to the stepper capability.
Hardware-wise, you'd need what's called an "H-bridge driver" to feed the motor. That driver would basically have two signal inputs: one to increase the throttle position and the other to decrease it. You might be able to use something like this: https://www.sparkfun.com/products/9670 although it's only rated 2 amps which I'm not sure would be enough. The inputs on that module would have to be connected to two outputs on the Megasquirt.
Then, the firmware would have to be modified to send the appropriate signals to the module at the right times. That's the fun part! Although it might not be that hard, there are probably "increase" and "decrease" hooks in there already due to the stepper capability.
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking
Be alert! America needs more lerts.
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking
Be alert! America needs more lerts.
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Re: A challenge for the electronics gurus
The stepper motor driver IC on the MS3 card is a dual H-bridge driver. It can drive a bidirectional DC motor by connecting the motor's leads to IAC1A and IAC1B, or IAC2A and IAC2B. Granted, it can handle less current than the SparkFun module: ~750mA.
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Re: A challenge for the electronics gurus
Not need to make firmware changes. Just the PWM signal from the Fidle set to 100Hz and this circuit:
Luiz Henrique - Piu
São Paulo
Brazil
São Paulo
Brazil
Re: A challenge for the electronics gurus
piubrazil wrote:Not need to make firmware changes. Just the PWM signal from the Fidle set to 100Hz and this circuit:
Nice! Do you have a components list?
Linfert Performance/321 Motorsports
SCCA 2019 SM National Champion Crew Chief
SCCA 2023 FP National Champion Tuner/electrical engineer
100s of MS systems built installed and tuned
Support the developers!
SCCA 2019 SM National Champion Crew Chief
SCCA 2023 FP National Champion Tuner/electrical engineer
100s of MS systems built installed and tuned
Support the developers!