VW 1.8T trothel "idle Valve" discution

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juansh2385
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VW 1.8T trothel "idle Valve" discution

Post by juansh2385 »

So as many other have try before I want to control the Idle valve of and 1.8t using Jean pwm converter and a standard ms. I read here that a special circuit can be made to control the valve but I was not convinced by the info posted and the lack of information in the details of this circuit.

To the point I have found that is possible to control the valve but I think a couple code mods are needed any help is appreciated.

Some of my findings are:

playing with the throttler in the bench I have manage to make it open and close. This valve is weird it only close at 0 dc and with my settings it start to open at 24 dc up to 32(full open) the only problem is that after the valve opens it does not close at all until the code reach around 0dc so if it open at 27 and I want to go down to 24 the valve have to go to 0 dc and then open until 24 as you can imagine this is a great inconvenience for the ms algorithm. I think I am going to need custom code to drive this valve correctly. ( The oem have another aproach witch invert the polarity of the cables to close the valve and revert to maintain the new position really fast)

the code needs command 0 dc the instant it needs to close the valve then as soon as the rpm goes down maybe look into a table that can be use for reference for a quick opening and then slowly increasing dc until it is at the desire rpm. a dead rage also might be necessary.
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Re: VW 1.8T trothel "idle Valve" discution

Post by piubrazil »

VAG throttle body is servo controlled plate for idle control. MS2 will never control this kind of plate without a specific hardware designed for it. It's pretty much like a DBW throttle, but the servo only actuates in the idle portion of the plate movement.
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juansh2385
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Re: VW 1.8T trothel "idle Valve" discution

Post by juansh2385 »

I know what you mean but I am planing on controlling this in a different way Believe it or not Right know is pretty functional just not as quick to close as I would like.

I know that the plate have also a different tps just for idle position and it probably also can be use to do what I want to do stop dc until x volts from that tps goes down to y (in a table) the hold position with Z dc (table).

Right know I am trying a rudimentary way trying to code that if I need to close the valve output 0 dc for X(ms) then go back to Y(dc) to hold that position until rpm gown down to z(rpm) If I need to increase rpm i just increase dc a(steps) and hold that position for H(s) in order to not open the throttler to much.
juansh2385
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Re: VW 1.8T trothel "idle Valve" discution

Post by juansh2385 »

I am trying to do this with the current hardware at hand right know is functional but not ideal. I a do not manage to do this the way I am trying then I'll look into designing a circuit to interface with the valve in a different way.
mike2coupe
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Re: VW 1.8T trothel "idle Valve" discution

Post by mike2coupe »

ive noticed similar behavior with the vw vr6 throttle body. I have the idle working ok by keeping the dc from going over 22.

if there was a special code option for the vw throttle body I think it would be better to have the code fully open the throttle body when the ecu comes on. and then lower the dc to the desired posion. that is how it works on the factory vr6 ecu.
juansh2385
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Re: VW 1.8T trothel "idle Valve" discution

Post by juansh2385 »

lowering the dc will not have any effect as piubrazil mention those (vr6 too) are servo plate and lowering dc will not make them close but in our cases when dc it 0 the plate return to a fairly close position on their own I am trying to take advantage of that. If I can't make them work fairly good like i think i can I'll just design and interface that can control the servo plate like they are ment to be. Maybe reverse engineering the factory design or using piubrazil suggestion that look acceptable and fairly easy to make with a little time to develop the circuit even though he did not gave specific components he described pretty well his design and how to make the compatible with a pwm signal like the one on ms systems (thanks for that piu I understand why you did not share the complete design but you did help a lot with that description of the over all design).

Juan
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Re: VW 1.8T trothel "idle Valve" discution

Post by eMTea »

I have connected the idle motor inverted compared to how vag does it (and running output signal inverted, 100%dc is no signal, "fully open") , so it only operates from rest position to fully closed.
I have only used open loop, but with an opprox 64% it idles at 900-950rpm...
With the valve in rest position is idle on hot motor about 12-1300rpm, so it is working better than nothing.
The downside with this, is at cold motor (-10 to -15degC), rest position does not provide enough air, so I have to keep the foot on the pedal the first 30-60sec.. No big deal, but not like the oem....

Rest position will also not provide enough air for antilag.
-MS3X, (V3 PCB) 1.2 RC 1 firmware. Controlling a light modified Audi 1.8TQ AEB 20v engine with Holset HE221W turbo, 299.4 HP and 400Nm at the hubs in Dynapack.
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Re: VW 1.8T trothel

Post by prof315 »

eMTea wrote:I have connected the idle motor inverted compared to how vag does it (and running output signal inverted, 100%dc is no signal, "fully open") , so it only operates from rest position to fully closed.
I have only used open loop, but with an opprox 64% it idles at 900-950rpm...
With the valve in rest position is idle on hot motor about 12-1300rpm, so it is working better than nothing.
The downside with this, is at cold motor (-10 to -15degC), rest position does not provide enough air, so I have to keep the foot on the pedal the first 30-60sec.. No big deal, but not like the oem....

Rest position will also not provide enough air for antilag.
I'm running the same way on my OBD2 ABA 2.0L with MS3 Pro. I found that by thoroughly cleaning the throttle things work fine cold. Also I actually have fairly decent control running closed loop. Not perfect, it tends to idle high the first time I idle after driving at a steady speed for 5 minutes or longer but in around town stop and go traffic it works quite well maintaining target idle.
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16vboost
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Re: VW 1.8T trothel "idle Valve" discution

Post by 16vboost »

So it sounds like there is a DC motor that will move the throttle body stop against spring return force. And there is a potentiometer that gives position feed back on the idle position. The spring isn't quite enough to always return it unless you remove all power from the motor. Am I correct?

If so, what I'd do is build a circuit that controls the idle using the pot as a reference. You could output idle PWM from MS (which can be essentially converted into a voltage). Compare this voltage to the voltage from the pot in the throttle body and move the motor accordingly. You could use an analog comparator to do this and amplify the output to drive the motor if it's low current. Or you could build a simple arduino circuit that does the same thing with an H-bridge motor driver. Has anyone done this? I'm sure some electronic gurus will chime in.

-Alex
juansh2385
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Re: VW 1.8T trothel "idle Valve" discution

Post by juansh2385 »

yes it has been done. I am replicating a design from piubrazil but I will not give details because he plans to make a commercial product out of it and is not my design to share. I will share the general information that he already share from the throttle.

http://www.msextra.com/forums/viewtopic ... ve#p340251
16vboost
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Re: VW 1.8T trothel "idle Valve" discution

Post by 16vboost »

Very cool. I found this chip http://www.onsemi.com/PowerSolutions/pr ... id=MC33030 which will take a reference voltage (PWM from megasquirt) and a feedback voltage and drive a DC motor up to 1 amp with its internal H-bridge. The data sheet has a schematic for an external, higher output H-bridge if needed though.

I'm running a GM stepper idle valve in my VW. I must say it works well, but I wouldn't mind the mechanical simplicity of this type of idle valve. Plus no need to wait for it to home. Let us know how this works out for you.

-Alex
eMTea
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VW 1.8T trothel "idle Valve" discution

Post by eMTea »

This is interesting!
I hope some with electronic interest will take a look at this :)
-MS3X, (V3 PCB) 1.2 RC 1 firmware. Controlling a light modified Audi 1.8TQ AEB 20v engine with Holset HE221W turbo, 299.4 HP and 400Nm at the hubs in Dynapack.
juansh2385
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Re: VW 1.8T trothel "idle Valve" discution

Post by juansh2385 »

it should hold at least 2 amp to be in the safe side
Last edited by juansh2385 on Sun Mar 03, 2013 8:06 pm, edited 2 times in total.
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Re: VW 1.8T trothel "idle Valve" discution

Post by racingmini_mtl »

One more problem is that this chip doesn't seem to be available from any distributor.

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piubrazil
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Re: VW 1.8T trothel "idle Valve" discution

Post by piubrazil »

My contribution for the comunity.

I'm using this circuitry to control the vag hybrid throttle:
Throttle 150T schematic.png
The PCB:
Throttle 150T PCB.png
The wiring to the MS:
Throttle 150T wiring.png
This circuit makes the PWM idle control totally transparent to the MS, and this circuit also work with Gslender's mod code.
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eMTea
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VW 1.8T trothel "idle Valve" discution

Post by eMTea »

Do you sell them?
-MS3X, (V3 PCB) 1.2 RC 1 firmware. Controlling a light modified Audi 1.8TQ AEB 20v engine with Holset HE221W turbo, 299.4 HP and 400Nm at the hubs in Dynapack.
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Re: VW 1.8T trothel "idle Valve" discution

Post by colossusuk »

I would be very interested in this, even if you could just supply the bare pcb and components I'm more then happy to solder it up myself. Idling on the vag throttle body has always been a pig as it never worked correctly and I bought a ford idle valve but never had a chance to fit. This would be ideal.

Many thanks
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Re: VW 1.8T trothel "idle Valve" discution

Post by prof315 »

Also interested (very!)
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16vboost
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Re: VW 1.8T trothel "idle Valve" discution

Post by 16vboost »

I don't think there's enough users of this throttle body to warrant this but a MS-controlled solution would be great. A separate full bridge circuit would have to be added to drive the DC motor back and fourth, and then the code could just check the analog value from the pot, run a PID algorithm and output to the motor. There are several half-bridge IC's available that have plenty of integrated features, requiring very little external components or electronics knowledge. But like I said, I don't think there's enough users that would benefit from this to warrant the development time.

-Alex
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VW 1.8T trothel "idle Valve" discution

Post by Paul_VR6 »

I am going to try a tip 120/125 pair on it next. It might be interesting to use the js0/1 pair from the stepper drive, its just not an option in the code at the moment.
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