Drive by wire functionality
We had some bad experience with the ref limiter and gear change ignition cut on our rotary engine. We are not sure it broke the engine but fact is that the engine hasn't broke any more since we deactivated the systems. Maybe it is just a coincidence. To be honnest the engine calibration has been changed also since then.
I fear activating these systems again and was looking for a solution.
With an DBW system I think we are able to restore the same functionalities as before and don't have to touch the ignition-system.
I found the following functionalities in the ECU manager software and want to check if they correspond with my understanding. If not could you please correct me so I do not have false hope when I go over to the purchase.
I want to use the throttle for up-shift. So the throttle angle changes towards 0% during a predefined time to get the load of the engine. The driver keeps his foot on the accelerator pedal. Typical behavior for dog engaged transmissions. But automatically done by the ECU and triggered by a load cell in the shift lever.
I want to use the throttle for down-shifts (throttle blip). To be able to shift faster into lower gear. The blip depends on the wheelspeed and gear which it is in and triggered by a load cell in the shift lever.
This I didn't find but never the less I would like to know if it is possible :
I would like to use the throttle to perform the pit limiter function. Throttle valve works like a PID with wheelspeed as feedback channel.
I would like to use the throttle for RPM limit when the driver revs to high. The throttle valve is controled in closed loop with rpm as feedback channel.
And of course with every change in throttle position the logic needs to follow the injection and ignition which comes with this throttle position.
Somebody did this before ? And who can give me some usefull tips and hints ?
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well I can tell you that with DBW you can incorporate Throttle Up (closing throttle) and Throttle down (blipping throttle) with the DBW.
Under the Function > Gear Shift > Up Shift DBW position/Duration or Down Shift DBW Position/Duration
The other items. That might sound out of scope as the pit limiter function won't be a DBW item as otherwise, from a logic bases, that means cruise control ;) of course I can be wrong and there is a way to do this "cruise control" logic which would be nice for street duties but if there is, I am not aware of it.
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Yes Figgie correct, you would use the Gear Shift function for your upshift "de-blip" and your down shift "blip". The strain gauge on the gear lever is the best way to do this....is it an H pattern or a sequential box? The problem on an H pattern is how do you tell the ECU if a rise or drop in force is an up or down shift.
The pit speed would not be closed loop but you should be able to make this work quite effectively through the DBW Translation table and Compensation table. This will be fairly easy if the driver stays in the one gear coming into the pits. The RPM limiter can be done in a similar way.
Just a note on the engine damage scenario (not being a rotary expert myself), some work that was done a few years ago showed the retard for the flat shift to be a problem if you went too far....resulting in broken apex seals.
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For determining blip/"deblip" you can use a clutch switch, most people will use the clutch on downshifts even if it is sequential/dogbox so they dont upset the balance of the car, you can actually make the rpms follow the exact road speed based on the best gear if you use a ton of tables so even if you have the clutch in for an extended period of time you will still have a perfectly matched engine/road speed granted this isn't built into the software but its easily possible with the number of user definable maps and i have done so successfully.
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In our case it is a sequential transmission. So the loadcell can do the job.
I do not understand how the DBW translation table and compensation table can do the Ref limiter and pit limiter function ? There should be a condition when it has to activate a certain table. I mean for example when the pit button is pushed then the table should be activated. Could you please clarify this a bit and also how it could work for the ref limiter ?
About the down-blip. The relation between RPM, gear and speed I can figure out with I2. But how I should implement this in the ECU manager software that is not clear for the moment. You say that with the range of the user definable maps it can be easily done. I know that the X and Y axle can be changed in all graph but the graph are all related to a certain subject. I mean fuel, ignition, auxilaries or functions. I can't see where I can find a user definable table with a complete freedom like the user conditions in the ADL2.
Can you please explain this also a bit more in detail how you did this ?Currently we have 3 throttle valves(manual) which are connected with each other. I was thinking to put one steppermotor on the axle and have them activated with one motor at the same time.
Is this possible ? Or do I have to mount 3 electrical throttle valves and expand with a DBW4 unit ?0 -
I do not know a way to do the ref and pit limiter function though im sure it could be done. How many axis is your position translation table currently? You can use any extra aux table to effectively add a table to your DBW position translation along with using your comp table that should give you all the feedback you need to have a throttle follower for vehicle speed, by using the clutch or default gear as one axis somewhere in there you can effectively turn the vehicle speed follow "function" on and off. Like i said its not made to do this but is possible. Doing this AND trying to build in limiter functions in the same manner could get pretty complicated and might not even be possible but either on their own should be very do-able...
As for the 3 throttles on 1 axle i would think as long as the motor had enough power to turn all 3 throttles as quickly as needed it would be no different than driving a single throttle so it should definitely work.
for the motec guys, why arent the limiter and pit speed functions dbw? this seems to make the most sense...
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ref limiter and gear change ignition cut on our rotary engine.
for the motec guys, why arent the limiter and pit speed functions dbw? this seems to make the most sense...
We broke cranks on our superbikes during pit lane speed limiter. If not dbw, can we have a bit more control over the cut functions? Control of cut patterns or cut % versus target error has worked really well. Also, a retard then cut function like you do with TC might be helpful.
Another thing that works for pit limiter is to set the ignition timing to a static, retarded number when the limiter is active. This takes a lot of response out of the motor and keeps the timing from moving around if the drivers is moving the throttle a lot.
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"Ben-S" wrote:
You can use any extra aux table to effectively add a table to your DBW position translation along with using your comp table that should give you all the feedback you need to have a throttle follower for vehicle speed, by using the clutch or default gear as one axis somewhere in there you can effectively turn the vehicle speed follow "function" on and off. Like i said its not made to do this but is possible.
Hi Ben,
Im not following here but is this what you are menaing?
DBW has Positition translation, and a Comp table....if you want more tables...can you use a unused AUX output table and set it up to generate a channel? Can you feed this generated value as an input into the COMP or POSITION TRANSLATION tables?
I have looked, you would be able to feed lets say a duty cycle of an unused output into another table, do you have other means of doing it?
Regards,
Martin
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This is much more difficult to explain than it is to show someone but i'm trying. Lets say you have your regular translation table already 3d and you are using your comp table... well if you want to have 2 more things effecting that channel your out of luck right? but if you use "aux 1 output" (for example) as the 2nd axis then you have another table than you can make 3d defining your 2nd axis so even though you have only added 1 axis to the control table that axis is based on two other parameters. It sounds more complicated than it is and im sure if you mess with it some you can get it working.
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thanks, ive figured it out :)
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So many bits in the one thread, I leave you alone for five minutes.... :lol:
Ok. Putting any old motor on three throttle boddies is definitely not recommended. All DBW setups should be correctly characterized by us to ensure they will not hurt anyone when they fail. Custom setups are something we really do not like for the simple fact that trial and error of a DBW throttle setup is just down right dangerous. Three smaller throttle with a DBW4 would be recommended.
Secondly I do not really like the idea of using the Cut Level as an axis for reducing power through the DBW simply because you get a level of cut to reduce power calculated by the pit speed function, for example, this then is used to reduce throttle, reducing the throttle reduces power and therefore the need for cut.....cut reduces and then so does the throttle reduction, it is a big vicious loop. Having said that I am sure messing with it enough will give you some kind of result...I am happy to be proven wrong.
If you only had the 3D comp table to do rev limiting and pit speed you would simple put your pit switch into an AT input and do a custom calibration for a 0 or 1 channel, this would be your axis on the comp table. The second axis could be RPM. Pit Switch off ("0" line of graph), the RPM axis is used to drop the throttle position where you want the RPM limit to be, I would also probably use some ignition retard aswell as was mentioned earlier. Pit Switch on ("1" line of graph), the RPM axis is again used for a lower RPM limit for in the pits again with some retard. You can also use the 0/1 channel as an axis with RPM for an Ignition Comp table for the retard in both situations.
Ben, just a note you are correct when you say "it is not designed to do it"...for a point of view. The whole idea of the Version 3 software was to give people the freedom the always asked for, unfortunately this needs to be balanced with a certain number of "lables" for various parts of the software to not totally confuse the average user. Realistically a lot of the software was not designed to do anything in particular (yes, it may have a lable on it) it is really up to you to decide what each part does.
The sequential box makes all of this much easier for the throttle blip/de-blip.
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Can we connect the pit limit button also to a dig input ? And link the digital input to an axle. Or does it has to be a AT input ? Because it is wired to a DIG input for the moment.
I mean :
If we want to exclude the coïncidence where the driver shifts in a different gear which is not foreseen as to be used with the pit limiter. Can we then use another table to solve this
Refer to an aux table on the Y-axle instead of the AT or DIG input. And use for the aux table on the x-axle : gear and on the y-axle : pit limit button. To be able to :
When the pit limit button is not pushed to limit the revs.
When the pit limit button is pushed to limit the revs depending on the gear which it is in.0 -
Provided you have enough tables you can do just about anything you can think of. Use the same concept with the throttle follower with this one, you know the channels involved you just have to find a place for them.
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In the meantime it is clear that the DBW can be used for :
pit speed
DBW de-blip for upshifts
throttle blip for downshifts (drive speed related)
rev limiter
TCSThe only thing where I still have some doughts is the reaction speed of the DBW.
For example for the rev limiter.
Lets say the rev limiter is at 8500 rpm.
And it is configured that from 8400 to 8500 rpm the throttle has to go from 100 % to 0 %.
I checked the logging (in 4th gear) how much time it takes to increase 100 rpm between 8400 and 8500 and its about 154 ms.
What is the time an electrical throttle valve can move from 0 % to 100 % and from 100% to 0%
Does anybody have a clue.0 -
well
I can tell you the LS2 DBW throttle can do it as fast as you mash or take your foot off the pedal. OF course with the motec you can adjust the sensitivity and limits (ie instead of 0%-100% you can do 0%tps=0% DBW & 100%tps = 40%DBW, of course not recommended :) ) Time, I am not sure as I never measured the LS2 DBW. Perhaps MoTeC can answer that.
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I didn't find any electrical throttles in the motec catalogue.
I need 3 throttles of 60 mm diameter. Can anyone recommend a unit which he already tested in combination with a 100 series ECU.
Can all functions like upshift DBW, downshift DBW etc... be used when I install a DBW4-unit.To have a window to return to the previous configuration I would like to connect the load-cel and throttle postion driver to the ADL2. And feed these channels through CAN to the M600. Will this be fast enough ?
This way I do not need to change the wiring of the M600 and in case it doesn't work we can change the inlet manifold with the old version.
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I'm using a generic Bosch 68mm DBW here but I know they do smaller units and MoTeC have the mapping for them.
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To easily use the pit button as a table axis it needs to be in an AT.
I would wire the TPD sensors dirrectly to the ECU but realistically there would not be enough delay in the CAN bus for you to notice.
I did some logging on the bench here with a big GM DBW throttle once (can't find the logging at this time) but the overview was this. The response of the throttle butterfly was as figgie said it was as fast as you could mash your foot, or in my case my hand. The 0-100% time was something like 20msecs but the interesting thing was that 0-5% the thing was speeding up and 95-100% it had to slow down but from 5-95% was frighteningly fast. I would be quite happy in saying it could be used for RPM limiting. Practically speaking you probably would not need it to go all the way from 100% back to 0% to stop the engine accelerating especially in the higher gears.
If you have an ADL2 and CAN back to the ECU I would not strees about running out of tables you could do all your trick calculations for pit speed and RPM limiting and CAN it back. Probably even do a closed loop speed control.
We don't actually sell any DBW throttle we just calibrate factory ones. The Honda CRV BDW I have on my 4AG is 60mm, is the same as some of the Subaru ones and we already have a calibration for it. Part number from the throttle is GMB1A J10000077940 40126.
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I see only one possibility to use the extra's of the ADL for the throttle position.
And that is for the DBW throttle blip. To create an RPM follower.
you create a 3D table in the ADL with
x-axle : speed
y-axle : gear
--> the output is rpm, this I should feed in a GP channel and rename it towards RpmVsLinkThen create a PID with :
feedback channel : RPM
Aim value : RpmVsLink
Output : GP renamed towards ThrottleBlipGet this ThrottleBlip over with CAN to the M600 and feed it in a user channel and then create a 1 on 1 2D table in Down Shift DBW Position table.
But for the Pit limit and RPM limit I do not have a clue. Can you make some suggestions so I can figure out a way to do this ?
In the meantime I found in our warehouse a throttel of 60 mm.
It is a Fomoco(ford) throttle, Mazda part no : L35M-13-640 originally used on the Mazda3 and 6 MPS.
Is the calibration for this electrical throttle known ?
I think the basics are the same as the L4 engine range from Ford.I mean the 1.8, 2.0, 2.3, 2.5 cc.0 -
P 25
I 10
D 20
Per. 2
DB .2
FF 4
Neg Int -25
Freq 8000
MV 14Keep in mind these values are not from motec i came up with them on a test bench, the values i was supplied by motec did not work (they did not test my throttle but had done mazda 6 throttles before). Neither myself or motec know why i would have had to use different values but i ran the car for over a year with those settings with great response and absolutely no problems. Use them at your own risk.
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"figgie" wrote:
wellI can tell you the LS2 DBW throttle can do it as fast as you mash or take your foot off the pedal. OF course with the motec you can adjust the sensitivity and limits (ie instead of 0%-100% you can do 0%tps=0% DBW & 100%tps = 40%DBW, of course not recommended :) ) Time, I am not sure as I never measured the LS2 DBW. Perhaps MoTeC can answer that.
Hi,
The GM DBW butterfly`s, ive read that they are not very reliable because of its internal gears that fail easier than most other units. Any comment on this?
How big is the LS2 unit? Whats the biggest DBW unit that you have calibrated at motec?
Thanks
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ElsmorrtelG,
It think you want to keep your setup quite simple to start with.Up Shift De-Blip: 3D table in the Gear Shift Function
Down Shift Blip: 3D table in Gear Shift FunctionNot sure why you want to throttle blip over CAN.
RPM Limiter: 3D comp table for DBW one axis is RPM. Do a big "-" comp when you get to the RPM limit you want.
Pit Limiter: Second Axis of comp table can be a 0 or 1. The 0 or 1 channel can be from the pit limiter switch changed to an AT or if you want to get tricky send the current digital status to the ADL to create a channel and send it back. If the driver can stay in one gear for the pits it will be easy, you would just need to do the same big "-" compensation at the RPM you want.About the only thing you may want to do in the furture maybe a PID RPM for the pit speed but for now it may be over complicating things. (sorry, trying to keep track of where we're at with this one).
All throttle bodies that have not been calibrated by MoTeC should be sent to us via your local dealer so we can generate a drawing for them.
The Earlier GEN3 V8 throttle bodies were pretty weak in the gear department, a problem that I believe GM picked up on quite a few years ago. The current ones seem to be fine and I have not heard of anyone breaking one in years.
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Can the calibration be done by Motec Europe headquarters ?
Is it possible to sent it directly over there not to waste time.An item where I didn't get a clear answer on. The 3 throttles I want to connect to the DBW4-unit are they capable to have the same opening angle with the same acceleration to have the same balance and AFR on the 3 rotors ?
The migration to DBW is getting its chape and you are right I need to keep it simple for starters.
So your proposition for the comp map is a thing I will do.I want to keep a window to go back when I am not able to get a good result. So I will connect the accelerator pedal, load cell and pit limit button to the ADL2.
That way I do not need to modify the engine wiring.We will have the ADL2, M600, Beacon Receiver, DBW-4 on the CAN bus.
So quite some info will be on the bus. When (how many channels sent and received) could we notice the delay ?Do I need to connect the pit button to an AT input on the ADL2 or can I use a switch input ? What is the problem why we can not use the dig input in the comp table ?
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"Martin" wrote:
Hi,The GM DBW butterfly`s, ive read that they are not very reliable because of its internal gears that fail easier than most other units. Any comment on this?
How big is the LS2 unit? Whats the biggest DBW unit that you have calibrated at motec?
Thanks
MartinNot sure were you read that. Most all DBW have to be gear reduced so the motor can actually open the throttle plate. The "motor" needs the mechanical advantage.
The LS2 DBW is 90mm in size. 90mm is the biggest DBW I have heard of. I know gm is going down to 82mm for the LS9 supercharged engine.
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Figgie,
Read it in the motec note "D11 GM DBW Motor.pdf"
Is the 90mm found on the LS2, which car?
In South Africa the Chevrolet Lumina SS Runs the LS2. Ill try and find out what the size is on this particular model.Does anybody know of aftermarker DBW units that might be available in future?
Martin
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"Martin" wrote:
Figgie,Read it in the motec note "D11 GM DBW Motor.pdf"
Is the 90mm found on the LS2, which car?
In South Africa the Chevrolet Lumina SS Runs the LS2. Ill try and find out what the size is on this particular model.Does anybody know of aftermarker DBW units that might be available in future?
Martin
Well in North America. The Corvette carries that engine and so does the GTO which is actually a holden Commodore in Australia.
Aftermarket DBW, Bosch makes alot of them. So does Magnetti Marelli.
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Figgie,
Do you mean aftermarket for racing applications? Has Motec characterised any of these? If you`ve got any links to sites regarding aftermarket DBW units please post it :)
The Holden Commodore is the same as the Chevrolet Lumina SS here.
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"Martin" wrote:
Figgie,Do you mean aftermarket for racing applications? Has Motec characterised any of these? If you`ve got any links to sites regarding aftermarket DBW units please post it :)
The Holden Commodore is the same as the Chevrolet Lumina SS here.
The bosch 68mm unit. Yes. the Magnetti Marrelli unit. I don't think so but I could be wrong.
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The DBW 4 only has one aim value going to it so all four (or three) throttles are always driven to the same aim point. There are no options to have the three throttles drive to different positions.
So, you need to be pretty careful in your calibration of the High and Low values fro the TP sensors in the throttle body, i.e they will all get driven to, say 100%, you need to make sure they are all set with 100% on the sensor being the same amount of throttle opening.
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Ive just measured an LS2 butterlfly on a Cev Lumina SS and its 90mm, must be the same thing.
"MarkMc" wrote:
The DBW 4 only has one aim value going to it so all four (or three) throttles are always driven to the same aim point. There are no options to have the three throttles drive to different positions.
So, you need to be pretty careful in your calibration of the High and Low values fro the TP sensors in the throttle body, i.e they will all get driven to, say 100%, you need to make sure they are all set with 100% on the sensor being the same amount of throttle opening.
Mark,
Would it be a big problem to have the DBW4 with multiple independant aim values? Could be very useful in turbo engines...
Martin
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When I did the ECU training course I was given the illusion that the DBW4 would be able to run 4 servo motors independently. Is this info incorrect????
I wanted to use a DBW4 to control 2 X throttle bodies, 1 X Exhaust Power Valves, and possibly 1 servo motor to control clutch actuation. Will the DBW4 DO this or not???
Has any one used a servo motor to control clutch actuation???
This is to be used on a 2 stroke GP bike...
Thanks for the input..
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