Motorcycle IAC valve

[lutorm]

Hey all,

I'm looking for options for an IAC valve for my 400cc bike Microsquirt setup. It's gotta be small. Anyone know of an existing bike PWM valve? I think the car options are going to be too large (and likely flow too much air.) Any suggestions would be appreciated.

Alternatively, a manual bleed valve might work too, just to have some sort of adjustment. I'd just like to avoid having to bo it with the throttle butterfly.

Thanks,

/Patrik

[robandnoah]

Maybe a small pneumatic valve like what we use for boost control...

[dontz125]

The '07+ CBR600RR uses a stepper IACV, the electrical parts of which can be had for $30-100 on eBay. Unfortunately the valve housing is part of the TB castings, thus the difficult part then becomes designing and fabbing a suitably sized body.

[lutorm]

The '07+ CBR600RR uses a stepper IACV, the electrical parts of which can be had for $30-100 on eBay. Unfortunately the valve housing is part of the TB castings, thus the difficult part then becomes designing and fabbing a suitably sized body.

Hmm interesting. Fabbing a body wouldn't be a problem, but I'd need to know what it's supposed to look like. Do you know the dimensions of that part?

Since I have a uS, I'd also need to put together a stepper driver. Do those look at the PWM output and convert those to stepper pulses, or is there a way to output the desired stepper pulses directly, like over CAN or something?

Edit: Upon further reading, it looks like you can configure the uS to get the stepper control IACEN/1/2 out on the spare pins. I assume "EN" is the motor enable, but are IAC1/2 step and direction as usually are input to stepper drivers? It might be just as easy to take a NEMA-8 stepper and build a little housing for it as adapting some existing thing.

[dontz125]

I don't know the dims for the IACV. Sorry.

I -do- have a PWM to Stepper controller. As you noted, it takes the PWM signal and converts it to a stepper position, based on driving it home on start-up. The 0-100% duty cycle converts to 255 or 510 steps, depending on internal switches. Based on a customer's request, I've talked to Jean Belanger (who wrote the code for this product) about adding options for 64 or 128 steps as well; he says it should be an easy change.

IACEN, IAC1 and IAC2 (PB4, PT7, and PT6) are only available on the MicroSquirt Module; bringing them out from the processor on a cased uS would involve significant surgery -and- changing both the firmware and the serial monitor (requires a BDM cable).

[lutorm]

IACEN, IAC1 and IAC2 (PB4, PT7, and PT6) are only available on the MicroSquirt Module; bringing them out from the processor on a cased uS would involve significant surgery -and- changing both the firmware and the serial monitor (requires a BDM cable).

Are you sure? I'm looking at the "Microsquirt hardware setup 3.3" pdf and in section 8.1 "Optional hardware - stepper idle driver" it shows the uS hooked up to the stepper driver using FIDLE, SPAREADC and SPAREADC2. And in TS I can select "stepper" for idle control and then in "connection" pick which pins the output should go to.

[dontz125]

Look again - that's not IACEN, IAC1 and IAC2; it is exactly what you listed - FIdle, SpareADC and SpareADC2. This is a code mod written by James to accommodate a particular design of PWM to stepper controller without any physical mods to the uS. Since you can't use the 3 'IAC' ports, you're giving up the two spare ADCs (you'd be using the FIdle pin for a PWM IACV anyway). I believe one of the options is to use ALED instead of SpareADC.

My controller doesn't allow the 'Holding current' or 'Moving only' options; it's effectively 'Always on'. That said, it only uses the single FIdle pin - not something to sneer at on an ECU as chronically short on I/O as a Microsquirt ...

[lutorm]

Look again - that's not IACEN, IAC1 and IAC2; it is exactly what you listed - FIdle, SpareADC and SpareADC2. This is a code mod written by James to accommodate a particular design of PWM to stepper controller without any physical mods to the uS. Since you can't use the 3 'IAC' ports, you're giving up the two spare ADCs (you'd be using the FIdle pin for a PWM IACV anyway). I believe one of the options is to use ALED instead of SpareADC.

My controller doesn't allow the 'Holding current' or 'Moving only' options; it's effectively 'Always on'. That said, it only uses the single FIdle pin - not something to sneer at on an ECU as chronically short on I/O as a Microsquirt ...

Well sure, those are the pins, but the tooltip says

Selects between normal stepper motor output connections or optional connections for Microsquirt add-on board.
For Microsquirt, the three options listed are the connections for IACEN, IAC1, IAC2

This makes it seem that the functions IACEN/IAC1/IAC2 are being routed to those selected pins (and yes there are other alternatives). So the question remains: what do the outputs on those three pins mean when you set this setting?

However, I think I found the iac stepper position in the CAN data, so then I think the easiest will be to use that. I already have an Atmega328 talking to the uS over CAN to send the wideband data anyway (that was my solution to the "chronically short on I/O", plus I'm allergic to analog... ) so it won't be a big deal to add a stepper driver to it.

[dontz125]

The new CBR500 (and a few others) uses the same stepper motor BUT has a separate valve body. There are weird openings on the valve body that would need an adaptor plate, but at least you have something for the actuator piston to ride in. The connector used on the actuator remains a mystery BUT the 2008-11 CBR1000RR has a separate throttle body wiring harness that includes this connector.

VALVE SET, IDLE AIR CONTROL; 16430-MGZ-D01; MSRP US$122.78, $90.49 at Partzilla
SUB-HARNESS, THROTTLE; 32104-MFL-000; MSRP US$29.91,$22.21 at Partzilla

$22 is a lot to spend on a connector / pigtail, but I'm hoping my connector connection can figure something out.

[prof315]

You might look at using a Canister Purge solenoid from a car..... They are mostly PWM and have 3/16-5/16" nipples I have used a VW purge solenoid on a number of small displacement applications as an IAC

[dontz125]

Agreed; I got myself focussed on the Honda stepper IACVs from dealing with a potential customer who IS working with such a thing. There are AC Delco solenoids for a LOT less than the $100+ I just blithely rattled off, using easy-to-find MetriPak connectors.

I'll sit down and drink my coffee ...

[prof315]

The VW valve uses a standard EV1 fuel injector connector.

[FAHR451]

I know this is quite an old thread but it has taken me this long to register on both MS forums ! I have had a V3 for around 10 years which I originally set up for a V12 Jaguar aero engine . I am refitting a V3 for a Triumph 675R 3 cylinder motorcycle engine which has a Keihin stepper that works on the shaft by opening the throttle valves and has no air passages to mess around with . . They also have a small air type solenoid which allows air into the cam cover for emission control .This could also be used as it is quite small about half the size of the common Bosch thing ! If you want one of the Supplementary air valves I have 2 I dont need. I will be using both the idle steppers on the 2 race engines Im afraid .The pin arrangement is standard 4 pin but wired diagonally so that each of the opposite corners show continuity . Work out which if forward and back by trial and error .I managed to get an engine loom so no problems but there are many of these available in breakers with damaged looms which have been cut by accident for the connectors.
I hope this helps further readers.