InTake/ThrottlePlates/VAGElectronicThrottle (2010-12-21 08:18:46)

Overview

This is a DBC (Drive by Cable) VAG throttle body used on a large range of VAG models. The newest VAG models have DBW (Drive By Wire) throttle bodies.

How it works

The DBC throttle body contains

Inside

See [DBC circuit diagram].

Cropped%20Full%20Size%20AEB_TB_IAC_Labels.gif


Pictures:

VAG_throttlebody.jpg

Can Someone tell me if the connector is micro-power-timer or junior-power-timer (likely) size? (see ConnectorSelection or tycoelectronics.com if unsure about sizes, or just measure the pin dimensions, like "2.68 x 0.8mm"). I saw an apparently matching female 2x4 one-end-rounded connector housing on the front-cover of a tyco catalog (could not find the product inside though, except in 2x4 pin microtimer size - on http://www.tycoelectronics.com ).

[2]

[3]

[4]

note that it has 2 speed-down gears inside, about 1/7 and 1/8 ratios (1/56 effectively).

Pictured throttle body is not fully motor driven.


NEW Kevin sent the following information:

It is for the VW/Audi cars made from 1996-1999. Drive by Cable.

It is a small electric motor and gear that turns a larger gear, that opens the actual throttle plate up to ~15%,

and

I have tried to use a PWM to control this, but the throttle plate movement is "weak".

For example, I can have it slightly open, and take my finger and physically move the plate, and it will not "self correct".

This translates to the engine speed fluctuates greatly, and proper control is impossible.

yes, because from the schematic it looks like +12V and -12V bidirectional drive is needed on the motor to move one direction or the other

This units operates OK at 100% open, and it will close to the resting position when the DC is 0%. But everything in between is bad.

(And I don't know how to close the plate from it's resting position to lower the idle from base)


Cropped%20Full%20Size%20AEB_TB_IAC_Labels.gif


Sensors

Finally, there is an "Idle Circuit" that I cannot use, because it is wired (internally) to make the TPS% go to "100%"

when connected.

This means that the TPS% moves when the IAC is active.


Wishlist summation:

Please measure current, and try to confirm that reverse driving voltage closes it (try to be careful, and use fuses).


Jorgen's comments :

There can be different versions of this throttle, but the ones I have seen worked fine.

There is an idle switch in the throttle, you need to use that to short the TPS signal to ground.

Possible interference with TPS-acceleration enrichment

There will be a sudden jump in TPS voltage when the idle switch become inactive as the TPS signal go from 0v to the output of the TPS instantly. I have expected this to give a squirt of fuel through the acc enrich but I have not tuned any of these cars myself and the customers who did the tuning didn't notice a problem even if I asked them to look for the problem. I'm sure that we can come up with a workaround if it's needed.

But it would obviously be best if we could have an idle signal input on the ECU.


Plan - steps

We need to find out

  1. hardware requirements, like current consumption in both direction (when moving, and likely higher when stopped)
  2. if the +-12V drive assumption is correct
  3. voltage mapping of the analog feedback signals for min 8 points, and min 4 points around idle
  4. implement firmware code for it
  5. find/tune suitable PID parameters
  6. write some vemstune help text for the new dialog

I'm pretty certain that Jorgen Karlsson is more knowledgeable than me, and he might confirm or deny some of our assumptions.


(OLD) Sources

Costs > 350 Euro. Anyone knows good sources ?

Anybody knows VW partnumbers of TPS sensors ? Or good sources of any TPS sensor?


See also