HiProfile

Well I just purchased one of these turbos, I'm hoping mine isn't a dud. It should just barely fit in my engine bay (I have A/C), but I'll have to change the outlet direction from 180* from the inlet to the usual 90* from the inlet. I noticed in your DSM board threads they said it was basicly an HX40 compressor, so I'm wondering if it might be easier to get an HX40 cover.

What I'm hoping is the turbo will spool nearly like the GT32 I was planning on getting, but will make more power. Any updates on the 57trim links?

series8217

Anyone here have access to electrical schematics for the Dodge truck that uses this turbo?

Also, I hate to destroy your guys' VGT control dreams but it's not a stepper motor. All you have to do is twist the shaft once to realize its not a stepper, but rather is a brushless DC motor.

That's right, the HE351VE actuator control does not use a stepper motor at all. There is an ST microprocessor on the board that runs a Freescale motor control chip. The chip controls the 6 MOSFETs you see on the top of the board. This for control of the 3-phase brushless DC motor. You should have been able to see those MOSFETs when you took the cover off the module. You can't see the controller devices in your partial disassembly because they're on the bottom of the board. If you want to get to them you have to carefully desolder the motor pins and external wires in order to take the board off. This isn't easy. It took me and my friend about 90 minutes to get the whole thing apart.
Another interesting note, the board is something like 5 layers. I didn't count but there's more than just the visible sides and a center line. It won't be fun to trace.

There are 3 hall effect sensors in a cage around the brushless motor. I haven't figured out what they're for yet but probably for determining relative motor movement. To figure out what the actuator position is.

The motor is geared very high against the actuator crosshaft. One of the gears in the gear set has a magnet on it. I think this may do some position encoding but I'm not sure yet; I don't see any detector that the magnet goes near. It may have been installed in the system but not implemented on board. Perhaps the prototypes did not work correctly.
A serial bus EEPROM is on board (also hidden on the backside IIRC) and may contain some usable program data.

Your best bet is to just make your own actuator assembly. You'll have to figure out how to get feedback on the actuator position. Unlike the HE351Ve here, the HE341Ve uses a completely different actuator system that has an external 0-5V position sensor. I would get that turbocharger if you want to have it easy for home made stuff..

I'll let you guys know when I have the HE351Ve system totally hacked. It'll be some time, I need to carefully remove the microcontroller and EEPROM and put it on a development board so I can unload the software and see if I can disassemble the program code.

Tom-Guy

Have you run the part numbers to verify that? They are more likely to be IGBTs.


Mmm, more likely they are there to monitor that the turbine fins don't become stuck/jammed, as the frequency the motor is cycled at dictates speed, which measured vs time results in relative position give or take a little slip. Without ever having seen one of these setups in front of me I have a mental image of a motor that doesn't spin far in one direction or the other, just flux the correct poles in slow motion to get the motor to turn over a third of a rotation and of course in the right direction. I could be wrong about all that, as I'm basing it off of AC inductor motor theory as I'm not a big expert on DC motors, but it's the way I'd design the system if it could be made to work like that.

HiProfile

I would have trashed all that nonesense and just gone with a simple geared motor, TPS-like possition sensor, and maybe an old-fasioned wastegate too (with a boost solenoid). This would be a lot easier to sense and control, especially where an exhaust brake is concerned. It would also allow some fail-safe function with the WG, so you aren't stranded if the VGT system DOES fail.

Anyways mine is scheduled for delivery tomorrow, so I'll see what I can do. I'm still trying to figure out how to combine the EBC's low & high boost settings with this. I want to have a free-flowing turbine after hitting low boost, but also not sacrafice high-boost spool time. I could use a solenoid valve with the actuator and use a GPO to only allow full VGT with a certain throttle %. Running all the scenerios through my head is making me

series8217

Actually I have not run the part numbers because they're upside down or covered in potting compound so I couldn't see them. I didn't think they are IGBTs based on the datasheet for the suspected controller:
http://www.freescale.com/files/analo...et/MC33395.pdf
If IGBTs are 100% interchangeable in MOSFETs in that application, then yeah they could certainly be them. I don't know that much about motor control. In any case, it doesn't matter.. all the control circuitry is there.. just write new code for the ST uC and do what you want. Assuming the board hasn't failed*.
The "H"s on the application diagram are the three hall effect sensors around the motor.
Wouldn't the turbine fins being stuck/jammed result in a change in current? The motor control unit has current sensing capability; I thought that would be to determine when the motor stops, so the MCU can map out the endpoints of the actuator when the system is first powered on.

Note: the motor control may be a custom IC from Freescale. It has the Freescale logo and a Freescale part number on it (google search resulted in some pages with the part listed with no description except "SSOP-32" package), but I can't find any reference to what it actually is based on those part numbers. It's just an 8 digit number. I ended up just looking up Freescale's 32-pin components and saw they had these MOSFET drivers... and sure enough the pinout and package matches the connections on the Holset board exactly. This is the ONLY such motor control chip listed on Digikey made by Freescale. I would like to find a pic of one, perhaps they just don't print "33395" on it and the part number is just some specific production run for this device.


The motor spins numerous complete rotations to get the full range out of the actuator arm. There is a big gearset in there to gear it down. I haven't had a chance to get the ratio yet. I thought they would just count the on time as well, but then I noticed that the clip that aligns the circuit board to the motor does in fact have three sensors in it, and I believe they're connected to the microcontroller. The motor control unit doesn't support them.


You should buy an HE341Ve then. It has the 0-5 TPS-like sensor for the position, and the actuator already uses a rod design which should be easier for you to adapt to your own controller.
You will still need a wastegate. The variable vanes act as a wastegate on the diesel turbos. Apparently there is gain in efficiency on the diesels by not completely bypassing the turbine, that's why they didn't go with a wastegate. You can read about Holset's reasoning in one of the papers on the UK site (www.holset.co.uk).

*What I've heard is the reason the HE351Ve units are so plentiful on ebay is because the actuator control units ARE failing, so dealers are replacing them with a newer style unit. I don't know why they would junk the whole turbo but I heard there is a new low-force actuator so perhaps there are internal changes that makes them obselete.

Tom-Guy

They are both FET based devices where voltage, not current, dictates how much voltage they pass. An IGBT is just a darlington pair arraingement with a FET switching on a big, robust BJT. So, yeah, they accept compatible signals. It's not really motor control specific, most of my understanding of DC/simulated AC phasing is from H bridges in welder or retarder brake applications. I get the feeling we both have our feet about as wet as the other, they've just been dipped in different ends of the pond. :P

The Table 5 Truth Table shows how the controller can offer +/-PWM control of pole pairs, as well as high/low control of individual poles. Looks pretty ripped, IMO, nice piece.


I don't see ay H's on the application diagram of the 33395 you linked to on the Freescale site? Are you looking at a different sheet or something? I'm not seeing any Hall pickups at all. If there's aythig of the sort it's controlled by the MCU and not the 33395 driver.


Yeah, it can probably be worked that way. It probably is.

Amazing what I'd discover if I read your post in it's entirety before i start replying to pieces of it. :P


Bypassing the turbine wheel is bad for efficiency on any application. Even when not producting positive boost pressure a turbo substantially increases an engine's power output... I have some dyno graphs somewhere comparing a pull with open wastegate (no spring, gate wired open) vs spring installed and me modulating TPS to stay ~0 psi vs a wastegate pull. The two runs with the wastegate spring installed and the gate closed made substantially more power from ~1500 rpms all the way to where the turbo makes first positive pressure at ~3600 rpms. Pretty crazy stuff.

series8217

Yes they are shown connected to the MCU. The 33395 doesn't use them directly.
It's on the first page.. the "simplified application diagram". I don't know why they're in the "simplified" diagram but not the detailed "typical application diagram". *scratches head*

Tom-Guy

Oh, they hid it in plain site. I hate when people do that ----.

Looks interesting. The MCU is looking for positioning information all right. Keep us updated, pretty please?

series8217

Yep I'll let you guys know what else I find out. The next step will probably be to finish identifying components on the board.. and then I want to pull the EEPROM and MCU off and download the code.

I also reaalllyyy need a Dodge truck wiring diagram for this turbo... so if anyone reading this has one, please post it. Even just a labeled pinout for the turbo actuator connector would help.

Another thing I need to do is find the sensor board for the RPM pickup, or design one. I think it's integrated into the chassis-side of the wiring on the Dodge. I wish they would've put that on the turbo too..

Tom-Guy

I've got Mitchell 5.8 on my laptop, when I get home I'll see what I can find out.