Holset VGT HE351VE Controller
05-14-2010, 02:12 AM
#31
0.0 BAR
Join Date: Sep 2008
Posts: 22
Thanks for the update... I check the forum often... I want to build my controller yesterday!!! 
So, If I understood right... you're saying that even after your success with the Picaxe and the MAP sensor input you still want to try the factory electronics?
Would you care elaborating on why you find that route still more appealing over you current design using the microcontroller... am I missing anything the factory board will do that your design won't?
Easier to get running? (no modifications) Cheaper? More reliable?... Just curiousity that arises from plain ignorance... remember I have never programmed a pic.. let alone understand about generating PWM and interacting with these complex electronics...
So, If I understood right... you're saying that even after your success with the Picaxe and the MAP sensor input you still want to try the factory electronics?
Would you care elaborating on why you find that route still more appealing over you current design using the microcontroller... am I missing anything the factory board will do that your design won't?
Easier to get running? (no modifications) Cheaper? More reliable?... Just curiousity that arises from plain ignorance... remember I have never programmed a pic.. let alone understand about generating PWM and interacting with these complex electronics...
05-15-2010, 09:28 AM
#32
0.0 BAR
Join Date: May 2010
Posts: 20
Hey dude, congrats on getting results with the factory motor, awesome stuff. I was thinking of using a servo to move the arm on the turbo but I'm a bit scared of the heat getting to it so I thought of doing the same and came across this thread while researching and I got a question or two.
Why did you feel it necessary to use the pot for position feedback? From what I learnt in control systems, the control loop would have MAP sensor input and VGT rack position as output with maximum boost as target. I can understand having it as an additional sensor to make sure the VGT rack's moving but it would add to the complexity of the programming and I personally see no need for it. Don't get me wrong, I'm not saying it's a waste of time but can you elaborate on why it's there? Are you moving the rack to X position for Y boost?
Second question: I've taken the five screws that hold the board to the 'lid' of the actuator unit but the board won't budge, do the 3 black round screw head looking things have anything to do with it? Do I have to unsolder the motor from the board to remove the board?
Last thing, the microcontroller on the actuator's board might have PWM pins but I don't think they'd be programmed to accept inputs from third parties. If they are used it's maybe for the controllers that were PWM controlled? Props for going down this path, it's not something I'd dare try. It'd be nice if it was as simple as feeding a PWM signal to somewhere on the board.
Why did you feel it necessary to use the pot for position feedback? From what I learnt in control systems, the control loop would have MAP sensor input and VGT rack position as output with maximum boost as target. I can understand having it as an additional sensor to make sure the VGT rack's moving but it would add to the complexity of the programming and I personally see no need for it. Don't get me wrong, I'm not saying it's a waste of time but can you elaborate on why it's there? Are you moving the rack to X position for Y boost?
Second question: I've taken the five screws that hold the board to the 'lid' of the actuator unit but the board won't budge, do the 3 black round screw head looking things have anything to do with it? Do I have to unsolder the motor from the board to remove the board?
Last thing, the microcontroller on the actuator's board might have PWM pins but I don't think they'd be programmed to accept inputs from third parties. If they are used it's maybe for the controllers that were PWM controlled? Props for going down this path, it's not something I'd dare try. It'd be nice if it was as simple as feeding a PWM signal to somewhere on the board.
05-15-2010, 10:21 AM
#33
0.0 BAR
Join Date: Sep 2008
Posts: 22
Hi there Skylar,
From what I've read here or in other forums, yes... you will have to desolder the motor to remove the PCB... and... just to make you even happier the motor is pressed into the housing... so getting it out won't be easy either.
As to your concern of using a servo in this hi-temp environment... well... you know the CHRA has ports for engine coolant to run through the actuator housing right? ... I don't know if even with this cooling the servo would fry though, internal temp should not exceed 90-95ēC but that would probably be more than some of the plastic components in regular servos can stand... it would seem to me that if the PCB components can survive in 90-95ēC, a hi-temp servo (if such thing even exists) would survive as well but that's only as I see it...
The best approach for sure is using the factory motor as It's been done here by CivicTsi as it was surely designed/tested to live happily in this enviroment. I'm just hoping that actuator failure due to hi-temps is NOT the reason so many of these turbos have been replaced under warranty at the dealers', I know it's excessive soot blocking the VGT system which triggers a service signal or prevents the turbo to work properly and then dealers just replace the whole unit under warranty.
My 0.2$
From what I've read here or in other forums, yes... you will have to desolder the motor to remove the PCB... and... just to make you even happier
the motor is pressed into the housing... so getting it out won't be easy either.As to your concern of using a servo in this hi-temp environment... well... you know the CHRA has ports for engine coolant to run through the actuator housing right? ... I don't know if even with this cooling the servo would fry though, internal temp should not exceed 90-95ēC but that would probably be more than some of the plastic components in regular servos can stand... it would seem to me that if the PCB components can survive in 90-95ēC, a hi-temp servo (if such thing even exists) would survive as well but that's only as I see it...
The best approach for sure is using the factory motor as It's been done here by CivicTsi as it was surely designed/tested to live happily in this enviroment. I'm just hoping that actuator failure due to hi-temps is NOT the reason so many of these turbos have been replaced under warranty at the dealers', I know it's excessive soot blocking the VGT system which triggers a service signal or prevents the turbo to work properly and then dealers just replace the whole unit under warranty.
My 0.2$
Last edited by Turboedmav; 05-15-2010 at 10:44 AM.
05-15-2010, 11:20 AM
#35
0.0 BAR
Join Date: May 2010
Posts: 20
Responding to your edited post:
If I were to use servo, I would mount it out of the way of the heat, well not in the midst of the heat. Probably on a bracket off the compressor housing, not bolted to the CHRA like the OEM actuator. I'm really just tossing ideas around at this point because I know RC servos are real easy to control (already have a real simple board with a PIC controlling a servo). Although controlling a RC ESC is no different to controlling an RC servo, I see the difficulty in setting end points so the motor isn't fighting the endpoints of the VGT rack, which I guess is the point of the feedback pot in CivicTsi's design.
I've got some experimenting to do I guess.
If I were to use servo, I would mount it out of the way of the heat, well not in the midst of the heat. Probably on a bracket off the compressor housing, not bolted to the CHRA like the OEM actuator. I'm really just tossing ideas around at this point because I know RC servos are real easy to control (already have a real simple board with a PIC controlling a servo). Although controlling a RC ESC is no different to controlling an RC servo, I see the difficulty in setting end points so the motor isn't fighting the endpoints of the VGT rack, which I guess is the point of the feedback pot in CivicTsi's design.
I've got some experimenting to do I guess.
05-15-2010, 09:00 PM
#36
0.0 BAR
Join Date: Sep 2008
Posts: 22
I'd like to know abut your progress as well Skylar... I'm really interested in learning to program microcontrollers and I know I'll get there somehow... later on... in the meantime I'll keep learning about analogic electronics and soon, hopefully, I'll jump into digital electronics and PICs...the possibilities are fascinating and endless for DIY guys like ourselves...
I agree with you on using the servo away from the exhaust housing, proably mounted on the compressor housing as you suggest, but keep in mind that the torque needed to actuate the VGT mechanism reliably is obtained through a couple of gears inside the actuator... I don't know if stand-alone servos are capable of such push/pull forces... considering levers to multiply force? How u addressing this?
I agree with you on using the servo away from the exhaust housing, proably mounted on the compressor housing as you suggest, but keep in mind that the torque needed to actuate the VGT mechanism reliably is obtained through a couple of gears inside the actuator... I don't know if stand-alone servos are capable of such push/pull forces... considering levers to multiply force? How u addressing this?
05-16-2010, 12:04 AM
#37
0.0 BAR
Join Date: May 2010
Posts: 20
Pushing the actuator arm around by hand, it seemed easy enough but it's been a while since I played with the he351ve. I'm guessing a 1/10th scale servo won't do it but a big sucker off a 1/4 scale should do it. but, that's to find out in testing.
With motors, especially, AC motors/brushless, it's easier to build them as small units with little torque and high rpm. To build low rpm, high torque units it requires 4 times the material to make is twice as slow or something. So they just end up gearing it like in the 351ve's actuator. I learned this in one unit at school but I didn't really like it/get into it. I might have it backwards but it goes something like what I explained.
I was thinking a servo used to control a wastegate flap on an internally gated turbo might struggle since there's a heap of pressure in the exhaust housing acting on the flap trying to force it open, but in the case of the VGT rack, I'm not sure if the pressure in the exhaust housing will force the rack open and whether it'll behave differently between bench testing and actual operation on a car.
You don't really need a huge understanding of electronics to do anything like this. I didn't really do analogue electronics, did a little bit of digital but I was really confused learning it and didn't really stick in my head. I just learned it all again while playing with PIC's although it did help having previously done it. I can recommend a book or two to read or write up a crash course in PIC's if you want.
With motors, especially, AC motors/brushless, it's easier to build them as small units with little torque and high rpm. To build low rpm, high torque units it requires 4 times the material to make is twice as slow or something. So they just end up gearing it like in the 351ve's actuator. I learned this in one unit at school but I didn't really like it/get into it. I might have it backwards but it goes something like what I explained.
I was thinking a servo used to control a wastegate flap on an internally gated turbo might struggle since there's a heap of pressure in the exhaust housing acting on the flap trying to force it open, but in the case of the VGT rack, I'm not sure if the pressure in the exhaust housing will force the rack open and whether it'll behave differently between bench testing and actual operation on a car.
You don't really need a huge understanding of electronics to do anything like this. I didn't really do analogue electronics, did a little bit of digital but I was really confused learning it and didn't really stick in my head. I just learned it all again while playing with PIC's although it did help having previously done it. I can recommend a book or two to read or write up a crash course in PIC's if you want.
05-16-2010, 12:56 AM
#38
0.0 BAR
Thread Starter
Join Date: Mar 2009
Posts: 45
Thanks for the update... I check the forum often... I want to build my controller yesterday!!!
So, If I understood right... you're saying that even after your success with the Picaxe and the MAP sensor input you still want to try the factory electronics?
Would you care elaborating on why you find that route still more appealing over you current design using the microcontroller... am I missing anything the factory board will do that your design won't?
Easier to get running? (no modifications) Cheaper? More reliable?... Just curiousity that arises from plain ignorance... remember I have never programmed a pic.. let alone understand about generating PWM and interacting with these complex electronics...
So, If I understood right... you're saying that even after your success with the Picaxe and the MAP sensor input you still want to try the factory electronics?
Would you care elaborating on why you find that route still more appealing over you current design using the microcontroller... am I missing anything the factory board will do that your design won't?
Easier to get running? (no modifications) Cheaper? More reliable?... Just curiousity that arises from plain ignorance... remember I have never programmed a pic.. let alone understand about generating PWM and interacting with these complex electronics...
05-16-2010, 01:13 AM
#40
0.0 BAR
Thread Starter
Join Date: Mar 2009
Posts: 45
Hey dude, congrats on getting results with the factory motor, awesome stuff. I was thinking of using a servo to move the arm on the turbo but I'm a bit scared of the heat getting to it so I thought of doing the same and came across this thread while researching and I got a question or two.
Why did you feel it necessary to use the pot for position feedback? From what I learnt in control systems, the control loop would have MAP sensor input and VGT rack position as output with maximum boost as target. I can understand having it as an additional sensor to make sure the VGT rack's moving but it would add to the complexity of the programming and I personally see no need for it. Don't get me wrong, I'm not saying it's a waste of time but can you elaborate on why it's there? Are you moving the rack to X position for Y boost?
Second question: I've taken the five screws that hold the board to the 'lid' of the actuator unit but the board won't budge, do the 3 black round screw head looking things have anything to do with it? Do I have to unsolder the motor from the board to remove the board?
Last thing, the microcontroller on the actuator's board might have PWM pins but I don't think they'd be programmed to accept inputs from third parties. If they are used it's maybe for the controllers that were PWM controlled? Props for going down this path, it's not something I'd dare try. It'd be nice if it was as simple as feeding a PWM signal to somewhere on the board.
Why did you feel it necessary to use the pot for position feedback? From what I learnt in control systems, the control loop would have MAP sensor input and VGT rack position as output with maximum boost as target. I can understand having it as an additional sensor to make sure the VGT rack's moving but it would add to the complexity of the programming and I personally see no need for it. Don't get me wrong, I'm not saying it's a waste of time but can you elaborate on why it's there? Are you moving the rack to X position for Y boost?
Second question: I've taken the five screws that hold the board to the 'lid' of the actuator unit but the board won't budge, do the 3 black round screw head looking things have anything to do with it? Do I have to unsolder the motor from the board to remove the board?
Last thing, the microcontroller on the actuator's board might have PWM pins but I don't think they'd be programmed to accept inputs from third parties. If they are used it's maybe for the controllers that were PWM controlled? Props for going down this path, it's not something I'd dare try. It'd be nice if it was as simple as feeding a PWM signal to somewhere on the board.
