HE351VE vg turbo control

[TSwidecki]

Hi my name is Tim i have been exchanging emails with Matt at diyautotune about controlling a variable geometry turbo with a megasquirt set up I would like to monitor the turbo shaft speed boost and drive pressure along with throttle position so my question is has anyone tried this or been able to make one work the turbo has a stepper motor to control the veins

[TSwidecki]

Matt thought that maybe the current boost controller could run this I guess it's based off of throttle position and rpm currently

[elaw]

The biggest hurdle may be the stepper motor. A Megasquirt only has one stepper-motor-capable output, and it's dedicated to idle control.

So you'd either have to find some sort of stepper-control board that can translate some other sort of input like voltage or PWM% into stepper position, or replace the stepper with a vacuum actuator.

As far as monitoring the turbo's speed, MS3 has multiple speed inputs that can measure the rate of a pulse output, but the frequency of the output from the turbo's sensor may be too high (the MS inputs are designed more for lower-speed applications like wheels or driveshaft). So you might need some sort of divider board to scale the frequency down to something the MS can handle. I have a vague memory of there being a discussion here about that before, you might try searching the site.

[TSwidecki]

Thanks for the input I don't need the idle control since this will be going on a Diesel engine so could I just use that for the vein motor control?

[elaw]

As far as I know, that output can only be used for idle control.

[Matt Cramer]

As far as I know, that output can only be used for idle control.

With the current firmware, at least; it would take different firmware to allow it to be used for other functions.

[TSwidecki]

How do you get different firmware

[racingmini_mtl]

How do you get different firmware

The code has to be written for it. So unless the developers decide they want to include it, you have to write it yourself.

Jean

[TSwidecki]

What do you need for that is there a certain software program

[radial]

My personal opinion;
Why bother to use electronics to control VGT, when this is so easily fixed with vacuum/pressure actuators.

After all, VGT is there to make a small turbo, perform like a bigger one. Its all about quickly building boost, and then make the turbo scuff allot of air (without insane rpm causing very hot air), and with minimum turbine restriction (reducing efficiency).

It's all achievable with simple actuators.

[TSwidecki]

I haven't been able to find one that made the exhaust brake function work and with actuators the veins close down while low load cruising whitch will cause pore fuel mileage

[jsmcortina]

What do you need for that is there a certain software program

http://www.msextra.com/tools

James

[Suprazz]

I'm running a he351ve on a 2jzgte right now.

I'm monitoring the turbo shaft speed with a small lm1815 circuit.

I'm not controlling the van yet but I "hacked" the he351ve controller. After that I plan to control it with a pwm signal from the ms..

[fpvmustang]

i'm also running a he351ve using a lm1815 for shaft speed. I'm having a small problem with shaft speed not reading over 65,000 rpm. On my to do list.
I'm currently playing with just using a spring to close the vgt and a stop to keep it from closing to far.
I would recommenced watching turbine drive pressure. for my setup I want to run 10 psi higher turbine drive pressure, then boost for fast spool.
then a 3 to 5 over for steady state. like pulling a hill.

[jsmcortina]

i'm also running a he351ve using a lm1815 for shaft speed. I'm having a small problem with shaft speed not reading over 65,000 rpm

Up to 650,000 is allowed in the pre-1.3 firmwares.

James

[Suprazz]

I had the same problem about the 65 000 limit. I just increased the Speed sensor number of teeth to 10 so I see the shaft speed divided by 10.

[fpvmustang]

I have noise on my shaft speed. I have not had time to run shielded cable.
I don't remember the input I used. but I do know the turbo will come apart long before MS3 is out of it's range.
I will try the changing the trigger teeth for fun. have less then 2 hours playing with the setup

[jsmcortina]

The 1.3 code also allows a high-speed input capture to better support the fast turbo shaft speeds.

James

[karlo]

I'd volunteer to hack up some code to control the VGT, if someone can find out what J1939 messages the actuator responds to. I've been looking for information on how to control the Delphi SRA (which it actually is), but haven't been able to find any.

- Karl

[fpvmustang]

i have a vgt control if someone wants to play with it. the wires were ripped out, but board looks good.

I think pneumatic control makes the most scene.
This is my theory. subject to change with further testing.
With ms3 closed loop control. We can set vgt closed ( set pressure diff. back pressure over boost) and have ms3 open vgt at set boost.
Setting the boost table will take time. We have to know what boost for the throttle position and rpm. Problem is it will change with altitude. Has to be set on the conservative side.
My idea is to run boost pressure to a pneumatic actuator. The boost pressure would try to close vgt. Exhaust pressure natural opens vgt.
With spring tension set to hold 20 psi exhaust pressure. (30 to 10 depending on engine).
Boost pressure applied to actuator maintains back pressure over boost differential. the size and leverage is critical to maintain balance.
once set boost pressure is reached the ms3 closed loop control supply's turbine drive pressure to other side of actuator. Opening vgt reducing pressure diff.(boost vs back pressure, turbine drive pressure)
With the closed loop we can set boost goals low at small throttle opening. At cruise the vgt would be pushed open by exhaust pressure and pulled open by manifold vacuum. reducing pumping losses.
I have boost 2 going to waste gate for max boost control. I'm currently using turbine drive pressure to keep waste gate closed.

I should have testing done by end of July.
I will post finding when I get there. Good or bad.