rusefi.com

We need a module to control stepper motors like the ones used in idle valves or in electronic throttle bodies.

Until such module is implemented, one can work on the software side using a module like http://www.ebay.com/itm//380764942691

Update: I am totally lost. How many kinds of electronic throttle bodies are out there?
1) regular motor
2) stepper motor (?)
3) solenoid (?)

For only a couple more $, you can get one with documentation and a supplier that will probably be around for years to come. http://www.pololu.com/product/1182 It costs less than $10 in qty 1, and doesn't need a heat sink. Also lots of example software can be found for this Pololu board.

kb1gtt wrote:For only a couple more $, you can get one with documentation and a supplier that will probably be around for years to come. http://www.pololu.com/product/1182 It costs less than $10 in qty 1, and doesn't need a heat sink. Also lots of example software can be found for this Pololu board.

Pololu makes a great second option as a development-phase board, thanks for the link!

With my modular approach, my idea is to gather all the schematics in the same KiCad format and test them all individually before all this would be combined into one larger board. It is a question of an opinion if we should dive into making the whole ECU boards from scratch, but that's the approach which works for me.

KICAD module for that AS4988 board found here. https://github.com/jharvey/Cinch_enclosure_template/tree/master/KICAD_Project/PCB-modules/pololu

kb1gtt wrote:KICAD module for that AS4988 board found here. https://github.com/jharvey/Cinch_enclosure_template/tree/master/KICAD_Project/PCB-modules/pololu

Jared, that was really helpful!

I've started an empty project with just this module to begin with - https://svn.code.sf.net/p/rusefi/code/trunk/hardware/A4988_stepper_motor_driver/

Cool, one caution with that module, which I need to fix, the via's are a bit to small for that footprint. The pins fit really tight, so just FYI, you'll want to open those holes up a bit.

kb1gtt wrote:Cool, one caution with that module, which I need to fix, the via's are a bit to small for that footprint. The pins fit really tight, so just FYI, you'll want to open those holes up a bit.

So far I've only used the http://svn.code.sf.net/p/rusefi/code/trunk/hardware/A4988_stepper_motor_driver/pololu_a4988.lib file - the pin-out I guess - and the standard QFN 28 package. With the standard QFN package from KiCad, am I going to be fine?

A4988 can be used to control low current actuators (for example idle valve). Throttle body motor requires much more current (about 6-8 Amp peak).

@, don't forget that all late throttle bodies (2002+ to now) use DC-motors with pulse duty control (about 500 Hz base frequency) and feedback from TPS.

Sergey89 wrote:A4988 can be used to control low current actuators (for example idle valve). Throttle body motor requires much more current (about 6-8 Amp peak).

How about http://www.digikey.com/product-detail/en/MC33926PNBR2/MC33926PNBR2CT-ND/3524219 ? Rumors are VAZ uses this chip

For $11 breakout board found here http://www.pololu.com/product/1212

russian wrote:

Sergey89 wrote:A4988 can be used to control low current actuators (for example idle valve). Throttle body motor requires much more current (about 6-8 Amp peak).

How about http://www.digikey.com/product-detail/en/MC33926PNBR2/MC33926PNBR2CT-ND/3524219 ? Rumors are VAZ uses this chip

I think it's ok because it is designed to control the throttle

Excuse my ignorance, but what is the benefit of an electronic TB? I can see how it would make cruise control easier to implement... but I can't imagine throttle response or reliability would be better than a good old cable, especially since most of the cars I have seen people post about are already cable operated.

The benefit is irrelevant if you have a car which already has an electronic TB. More and more cars will have ETB, one of my potential test vehicles (2003 Cooper) has an ETB already.

ETB is great thing for any car- stock,drag, drift, rally...
Cable throttle will stay in 20 century...
Because ETB give much stable and accurate response to accelerator position and requested torque.
Especially on powerful turbo engines where engine torque control is at edge of life and death.

Generally you'll find the TB is much more open when the computer can do it. Basically your foot pedal is for commanding power. Traditionally you commanded power by letting in more air. There is a complete range of rich and lean conditions that can obtain the same amount of desired power. When you had a cable to your foot, you would allow more air and the to compensate you would have to dump more fuel. However with ETB you can vary both fuel and air. So to get a certain amount of power, the ETB can open the TB, dump more fuel, then after a little bit of time, it can close the TB and vary the fuel ratio, all while your foot is at a single position. By using electronic TB, you can vary the amount of air in the cyl and maintain a more clean burn for the same amount of power. Picture Xtau but for intake air not fuel. I once had a VW with ETB. It basically opened the TB fully all the time, then controlled intake air by turbo controls.

ahha, thank you for a good explanation kb1gtt! It makes more sense now... I knew I must have been missing something.

Sorry for the slightly off-topic question, now back to the discussion at hand!