Variable vane geometry turbo

[Martin]

Has anybody worked with these?

More specifically the Garrett VNT turbo that to me seems to be servo controlled?
Any help would be greatly appreciated!

Thanks
M

[Mazi]

Maybe it will help a little.

Porsche 997 has duty cycle controlled servo (signal not power). I have to check the frequency. Frequency and duty cycle must be in range otherwise it will travel into the limit position and will stay there. Control signal must be present when servo is powered on otherwise it will stay in initial position. Vane position is sent back to ECU in duty cycle form with slightly different frequency.

[Martin]

Thank you Mazi,


Is this KKK or Garrett?

Do you have pinouts?


Thanks
M

[Mazi]

Aaaaaaa.... Maybe it was KKK. But not 100%.

Frequency is 250Hz and duty must be between 25% and 85%.

[SportsCarRacer]

Hi,

I am very familiar with the GARRETT version of the VNT turbo, as i work for a large multinational car company that uses them a lot...i'm in engine test/development.

You are correct, they are essentially a servo motor. The garrett type come in two flavours.....one with all the servo control built into the black box of the actuator, with only a 0-100% duty signal coming from the PCM, and the more common "povvo" version where the servo control parts move onto the PCM board, with the motor voltage controlled by the PCM, with the feedback for position fed back to th PCM via an LVDT (not a pot) 0-5v signal.

I have been playing with a couple of the latter type for my own racecar project, and have built a few servo boards to allow ANY PWM output from a spare motec M800 output to send 0-100% signal to control the VNT actuator...i don't have heaps of cash for DBW4..but i don't think they allow seperate setpoints anyway. I'm using two actuators to try to control the turbine speed of two seperate turbos......it all works fine on a HIL rig simulator, next step is to build the engine and try in car! My servo boards essentially turn one of the "povvo" dumb actuators into one of the duty-cycle driven type...much more versatile to control.

ONE THING TO BEWARE OF with the GARRETT actuators at least, is that they don't like being driven above 85-90%...there is the risk that the little worm nut inside comes off the worm above 90%...in a production application, they are limited to 5%-85% range....it's easy to fix to pull the actuator apart to fix though, but would be a pain if it happened in a race!

If you send/post some pics of your actuator & turbo, i'll probably be able to dig up the pinouts for it. Also, might have the motor drive volts/current limit as well.

What's your turbo off??

Sayonara!

[SportsCarRacer]

One thing i forgot.....the default or "standby" position of the vanes is usually the 50% point, driven by the PCM (the actuator by nature stays where it is after power removed from the motor)...

The 0% is the low speed setting (vanes closed, pointing directly onto turbine), 100% is high speed setting (open vanes, turned to open flow more tangentially to turbine)....bus as mentioned typically max is 85%.

hope this helps!

[Martin]

Hi,

Thanks a lot for your help and input. The turbo if of a BMW M57TUD30 Diesel, single turbo. Ill take a picture and mail it to you. If you can PM me your email address ill forward you all the information I have and the Pictures.

Thanks!
Martin

[Martin]

Here are the pictures of the turbo.
Is this good enough to identify it?

[Martin]

This is the exhaust housing with the actuator

[SportsCarRacer]

Hi Martin,

Sorry about the delay, been pretty busy the last week or so!

Thanks for ther pics, the one you have is the most common type (from Garrett, anyway), but it's the one that if the travel is exceeded, the gear comes of the end of the worm...don't woory, it's easy to fix, just flip of the case retaining clips, carefully pull the black cover up, and re-engage the gear! Cover on and away you go! As i said, robust range id 5-85% of total travel.

Pinouts are as follows: Pin one is at the "round end" of the connector (not the short side with the flat on it)
In your pic above, with the pins vertical on the page,the PIN1 is at the TOP of the connector

PIN1 Motor Pwr +
PIN2 Motor Pwr-
PIN3 Hall Posn sensor gnd (sigrtn)
PIN4 VGT Position signal
PIN5 Hall Posn sensor pwr (vref)

Other than that, it's a normal servo motor! Zero postion (really 5%) is vanes fully closed(low speed operation), full position (really 85%) is vanes fully open (high speed position)....typically controller should default to 50% postion to minimise risk of overboost...very easy to get with vanes fully closed and a bit of a rev!

Be VERY careful with exhaust temps with VNT turbos...the vanes begin to bind, and have seen it happen very quickly...sometimes they rcover, sometimes they are too distorted on the guide plate ring to work properly again.....don't go over 850, typically 780 degC is ideal (after all it is a diesel!)

Also, bear in mind that the actuator and turbo are a matched pair, and i know at least in our applications, the actuator is not available as a separate component...you need to buy a whole turbo......

Enjoy, would be interested to hear your exploits / progress!