Project : DBW throttle with Jean's TinyIOX & Polulu JRK12v12

A forum for discussing the MegaSquirt related (but non-B&G) board development, assembly, installation, and testing.

Moderators: jsmcortina, muythaibxr

Re: Project : DBW throttle with Jean's TinyIOX & Polulu JRK1

Postby Matt Cramer » Mon Oct 02, 2017 7:16 am

anzelmi wrote:Now also Maxxecu and Ecumaster include DBW feature. When does Ms3pro get this feature?


When we can absolutely, positively guaranty we won't repeat Toyota's "Moving Forward - whether you're on the gas or the brakes!" disaster. One of our engineers had a racing teammate whose car got pushed into the wall when a DBW system from a big name motorsports ECU manufacturer got locked fully open.

Any DBW device we build at DIYAutoTune is going to take a similar approach to Haltech's "redundant watchdog" type approach. The MS3 architecture doesn't have this feature, but it could be implemented in an external CAN device, or in a next generation device running a different processor.
Matt Cramer
Super MS/Extra'er
 
Posts: 13743
Joined: Thu Apr 16, 2009 8:08 pm

Re: Project : DBW throttle with Jean's TinyIOX & Polulu JRK1

Postby ol boy » Tue Oct 17, 2017 9:38 am

I was playing with a GM DBW this past weekend using a teensy3.2 receiving CAN messages from an MS2 for throttle position. Driving the DC motor was simple with a low side driver but it took some fooling around to get the valve to hold position correctly. The return spring is stout enough that the valve snaps shut quickly so I don't see much need for a H-bridge. Since the motor also winds up the internal return spring a bit of hold current is required to hold the valve in the desired position. As the spring is wound up the hold current also needs to increase to get better response from a changing input.

Has anyone sorted a control loop for a DBW yet?

Matt. I though Toyota's problem was the floor mats getting stuffed under the pedal assembly, not the manufactures software/hardware problem.
306 SBFord, Torquer II EFI intake, 60 lbs injectors, 8 LS2 coils, VS Racing 7668 turbo, 4R70W, MS2extra 3.4.x_ish
ol boy
Super MS/Extra'er
 
Posts: 1198
Joined: Mon Sep 10, 2007 3:06 am
Location: Tucson, Az

Re: Project : DBW throttle with Jean's TinyIOX & Polulu JRK1

Postby jsmcortina » Tue Oct 17, 2017 10:17 am

ol boy wrote:Matt. I though Toyota's problem was the floor mats getting stuffed under the pedal assembly, not the manufactures software/hardware problem.

That was their initial excuse.

The court found that their software was hopeless.

James
I can supply, repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: viewtopic.php?f=104&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
jsmcortina
Site Admin
 
Posts: 33991
Joined: Mon May 03, 2004 1:34 am
Location: Birmingham, UK

Re: Project : DBW throttle with Jean's TinyIOX & Polulu JRK1

Postby ol boy » Tue Oct 17, 2017 11:08 am

I have a 2000 Ford diesel pick up, it's DBW as all non injector pump diesels are. I poked my head under the dash and found a single pot style pedal sensor. I guess a diesel being only fuel based(no throttle valve) system has it's own level of fail safes while a gas motor in theory only needs air volume for the injection system to produce power output.

Shouldn't both the desired commanded throttle position(foot pedal) be checked against the current condition/state of the motor? If foot pedal is at zero and engine is at 5K rpm making 10# then something is wrong.

Are all DBW throttle bodies the same? are they all a geared DC motors? The GM truck unit I was playing with doesn't shut all the way and would require a H-bride to get the last 10%, but would the engine even run with the valve completely shut or is that the default cranking position? so many questions..
306 SBFord, Torquer II EFI intake, 60 lbs injectors, 8 LS2 coils, VS Racing 7668 turbo, 4R70W, MS2extra 3.4.x_ish
ol boy
Super MS/Extra'er
 
Posts: 1198
Joined: Mon Sep 10, 2007 3:06 am
Location: Tucson, Az

Re: Project : DBW throttle with Jean's TinyIOX & Polulu JRK1

Postby jsmcortina » Tue Oct 17, 2017 11:21 am

You need to be able to close it beyond the spring position.
All DBW safe pedals have multiple pots.

James
I can supply, repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: viewtopic.php?f=104&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
jsmcortina
Site Admin
 
Posts: 33991
Joined: Mon May 03, 2004 1:34 am
Location: Birmingham, UK

Re: Project : DBW throttle with Jean's TinyIOX & Polulu JRK1

Postby jsiedlicki » Tue Oct 17, 2017 3:33 pm

ol boy wrote:Are all DBW throttle bodies the same? are they all a geared DC motors? The GM truck unit I was playing with doesn't shut all the way and would require a H-bride to get the last 10%, but would the engine even run with the valve completely shut or is that the default cranking position? so many questions..


Most DBW throttle bodies use geared DC brush motors. Their neutral position is slightly open to allow the motor to run at a fast idle in case there is a malfunction and power to the throttle is cut.
MS3-Pro (6 cyclinder Subaru EZ36R)
MS2-extra (8 cyclinder Ford 347 stroker)
jsiedlicki
Helpful MS/Extra'er
 
Posts: 139
Joined: Sun Jun 23, 2013 3:52 pm

Re: Project : DBW throttle with Jean's TinyIOX & Polulu JRK1

Postby jamies » Tue Oct 17, 2017 5:46 pm

you could look at adapting GM TAC?
if you figure out the data stream, then it will also support cruise control etc too
jamies
Experienced MS/Extra'er
 
Posts: 342
Joined: Tue Apr 07, 2009 12:22 am

Re: Project : DBW throttle with Jean's TinyIOX & Polulu JRK1

Postby ol boy » Tue Oct 17, 2017 6:35 pm

Im thinking of an extender board.. Teensy3.2 or 3.5. Ive slowly moved my picaxe based transcontroller over to a 3.2 along with CAN data and uSD logging. I modded the end stops on a GM DBW unit and just low side switch the motor with feed back from one of the pots. The unit seemed to need around 25% duty at 8khz to just hold position and that hold duty seems to change with position and voltage applied to the motor.

I played with adding duty cycle based on the delta from the commanded position to the feedback position plus the hold value. Seemed pretty responcsive in both open and closeing. This was all bread boarded setting on the glove box with the DBW sitting on the dash.

Watched a youtube vid of a guy using a small DBW unit for blow off valve. Might be other uses than just for throttle...
306 SBFord, Torquer II EFI intake, 60 lbs injectors, 8 LS2 coils, VS Racing 7668 turbo, 4R70W, MS2extra 3.4.x_ish
ol boy
Super MS/Extra'er
 
Posts: 1198
Joined: Mon Sep 10, 2007 3:06 am
Location: Tucson, Az

Re: Project : DBW throttle with Jean's TinyIOX & Polulu JRK1

Postby Matt Cramer » Wed Oct 18, 2017 7:36 am

jamies wrote:you could look at adapting GM TAC?


That is one possibility under investigation.
Matt Cramer
Super MS/Extra'er
 
Posts: 13743
Joined: Thu Apr 16, 2009 8:08 pm

Re: Project : DBW throttle with Jean's TinyIOX & Polulu JRK1

Postby jsmcortina » Wed Oct 18, 2017 12:24 pm

ol boy wrote:Watched a youtube vid of a guy using a small DBW unit for blow off valve. Might be other uses than just for throttle...

Using a servo throttle for functions like this or controlling bike secondary throttles etc. is all fine and shouldn't have the safety-critical implications.

The primary throttle is a different matter altogether.

James
I can supply, repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: viewtopic.php?f=104&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
jsmcortina
Site Admin
 
Posts: 33991
Joined: Mon May 03, 2004 1:34 am
Location: Birmingham, UK

Previous

Return to Expansion boards

Who is online

Users browsing this forum: No registered users and 1 guest