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Spork |
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An improtant part of this will be to talk to the engine ECU whether it be aftermarket or standard and retard timing to reduce engine power during shifts. Without this, particuarly on a modified engine the box will wear prematurely and shift poorly (or not at all!).
I know motec and some other aftermarket ecu's can accept a 'gear change ignition cut' signal or similar. Sounds like an interesting project. The problem will be not 'when' to shift but 'how' to shift. At the moment the transmission is extensively calibrated for each different varient of vehicle it is on. eg. LPG vehicles have a different calibration to sedans and are different to utes. Making a totally universal controller will be impossible, you have to select the right ammount of control to give to the customer to tune each vehicle type.
_________________ Manual EL Gli.
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mikejh |
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Quote: An improtant part of this will be to talk to the engine ECU whether it be aftermarket or standard and retard timing to reduce engine power during shifts. Without this, particuarly on a modified engine the box will wear prematurely and shift poorly (or not at all!).
I know motec and some other aftermarket ecu's can accept a 'gear change ignition cut' signal or similar. Yeah, you're right, then we can all have the Toyota Soarer/Supra f@rt when we change gears. I am not so sure the BTR uses this method. Torque reduction is applied in reverse gear, but the manual says nothing about torque reduction during gear changes. I think that is why they use the S5 solenoid to reduce line pressure during shifts - to soften the shift (and increase wear). The Toyota boxes don't have control over line pressure so they would have to control the torque by retarding the timing during shifts, hence the f@rt they put out. |
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FPV_GTp |
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mikejh wrote: justfordima - I would be using an Atmel AVR as I have done a lot of work with them in assembly. C is great if you like using up alot of your flash memory, but its been a while since I have used it, maybe its gotten better.
The Freescale processor is awesome but I don't think the trans controller will need such a powerfull processor. The AVR is a RISC processor and runs at 16MIPS so it should be up to the task. If the bands and clutches are larger, what are the other internal parts that would require sourcing. A lot of the wear in the clutches is due to their slow and sloppy shifting. If you used a higher shift pressure then they wont suffer as much punishment. Hi never enough processor power , leave more room for other functions the other components in the transmission will be fine for big power and the only way to find out is apply big horsepower to the transmission and see where all the weak pionts are may involve destroying several boxes until all faults are founf out clutches and bands can be made of better high temperature operating materials and greater work loads the other componets can also be improved several ways but i would be starting with the weakest parts first and then the hard componets second Do you guys that are into electronics wanna give it a go ?? cheers
_________________ WANTED - Complete BTr4 and zf 6hp26 automatic transmission 6 cylinder and V8 transmission(s) suit rebuild? Drop me a PM if you can help would be greatly appreciated - thanks |
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Spork |
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I have experience programming Atmel AVR micro's (the vehcile datalogger) and interfacing to vehicle sensors.
I also happen to know a bit about how ION 4speeds work. But I don't have enough time to make this a full project. If someone else wants to do this I can help with technical knowledge.
_________________ Manual EL Gli.
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FPV_GTp |
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[quote="Spork"]I have experience programming Atmel AVR micro's (the vehcile datalogger) and interfacing to vehicle sensors.
I also happen to know a bit about how ION 4speeds work. But I don't have enough time to make this a full project. If someone else wants to do this I can help with technical knowledge.[/quote hi would want it to be a full time thing for anyone otherwise it would be fair would be nice as a fordmods forum group to band together split the work load and help each other listen any ideas you guys may have to help the idea become reality cheers
_________________ WANTED - Complete BTr4 and zf 6hp26 automatic transmission 6 cylinder and V8 transmission(s) suit rebuild? Drop me a PM if you can help would be greatly appreciated - thanks |
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data_mine |
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One of the lesser know workshop manuals (not Gregories) actually tells you what voltages are required for each shift pattern. That's all the hard work done.
I'll see if I can find my copy, and I'll post back.
_________________ 1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow |
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FPV_GTp |
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data_mine wrote: One of the lesser know workshop manuals (not Gregories) actually tells you what voltages are required for each shift pattern. That's all the hard work done.
I'll see if I can find my copy, and I'll post back. i have all the factory manuals and a dedicated BTR tranny rebuild manual also but dig ur stuff out seems a few of u guys are keen on the idea here nice cheers
_________________ WANTED - Complete BTr4 and zf 6hp26 automatic transmission 6 cylinder and V8 transmission(s) suit rebuild? Drop me a PM if you can help would be greatly appreciated - thanks |
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mikejh |
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Quote: One of the lesser know workshop manuals (not Gregories) actually tells you what voltages are required for each shift pattern. That's all the hard work done.
I'll see if I can find my copy, and I'll post back. Sorry if I sound rude, but thats all the piss easy work done. The main shift solenoids and lockup TC solenoids need 12V and the S5 solenoid needs between 200mA and 1.2A of current - variable to change the shift feel. |
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FPV_GTp |
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mikejh wrote: Quote: One of the lesser know workshop manuals (not Gregories) actually tells you what voltages are required for each shift pattern. That's all the hard work done. I'll see if I can find my copy, and I'll post back. Sorry if I sound rude, but thats all the piss easy work done. The main shift solenoids and lockup TC solenoids need 12V and the S5 solenoid needs between 200mA and 1.2A of current - variable to change the shift feel. ok your not being rude the torque convertor solenoid need a dc current of a 12 volt supply thats easy where the s5 has to be pulsed at a variable frequency depending on the condition required from the trans so where do we start ????? seen some methods where guys have push buttons for gear selections for all the solenoids on other transmissions where the BTR is a little more tricker where the line pressure needs to be adjustable at the S5 solenoid wonder what the line pressure is if the solenoid is fully on ie 12volts supplied to it when the engine is running at light throttle cruise right upto wide open throttle ( LEAD FOOT MODE ) ok will set up a test rig at work with a transmission and start testing some of the stuff have a motor and trany ready to go cant do it to my every day car be funny driving around wif all these gauges and wiring and buttons in the front seat area LOL cheers
_________________ WANTED - Complete BTr4 and zf 6hp26 automatic transmission 6 cylinder and V8 transmission(s) suit rebuild? Drop me a PM if you can help would be greatly appreciated - thanks |
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mikejh |
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Hey FPV_GTp, where can I get one of those dedicated BTR tranny rebuild manuals, is it a genuine Ford manual ?
The S5 solenoid needs to idle at 200mA while in normal driving mode which gives a high line pressure. During shifts, the ECU ramps this current up, (anywhere up to 1.2A which would be fully on at 12V) which lowers the line pressure and therefore softens the shift. If you drive around with the solenoid on, you might not go anywhere, either that or it will slip so much during shifts you'll fry your clutches. If you use less current during a shift the shift will be firmer because the pressure will be closer to line. (And if you unplug the S5 you'll get damn hard shifts) Also, the S5 needs to be pulsed at a fixed frequency but variable pulse width. Its not entirely correct to refer to it as line pressure, its really shift pressure which is independant of line pressure. |
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FPV_GTp |
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hi
the BTR manual is available from APROVED TRANSMISSIONS in melbourne the ford workshop manaul is available from TECHNICAL BOOKSHOP Melbourne cheers
_________________ WANTED - Complete BTr4 and zf 6hp26 automatic transmission 6 cylinder and V8 transmission(s) suit rebuild? Drop me a PM if you can help would be greatly appreciated - thanks |
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Spork |
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The transmission control is really complex. -This is from a textbook on auto trans design.
To give an idea lets consider a 2-3 shift. One element is coming off (the front band) and another is coming on (the clutch). First the solenoids switch to direct fluid to the correct valves in the valvebody. The S5 is still at maximum line pressure to start filling the clutch piston. But it has to ramp the pressure off to allow the band to disengage then it has to ramp the pressure on again to engage the clutch. The trick is balanceing the release of the band against the apply of the clutch so that the transmission doesn't bind up or flare. This is very difficult and requires different setpoints depending on input shaft torque and RPM. Not only that but transmission fluid temperature has an effect aswell. Even that input shaft torque depends on where the torque converter is operating and can be up to twice the engine torque. Finally this shift requires the engine to limit it's torque at exactly the right moment to help with the balance of forces between the offgoing element and oncoming element. So don't underestimate the difficulty of this project. We are going to need a PWM duty cycle to run the S5 solenoid, this duty cycle has to be set by tables that allow the S5 to ramp to target points during the shift. Those points will have to be determined from lookup tables that depending on what RPM, Input shaft torque, transmission temp, and degree of shift firmness is required. You will need one profile for every shift that is possible. ie. not just 1-2 2-3 3-4 but 1-4 3-1 etc. Realistically we will never get as smooth shifting as stock, but I think it should be possible to define a set of shifts that work fairly well for one engine/transmission combo, then just make the engine torque adjustable so when someone mods their engine they just put in their new torque curve and the trans re-calibrates itself.
_________________ Manual EL Gli.
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justfordima |
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...it does sound complicated starting from scratch. But since there is so much information on the stock shifting and operation.. then we are just reverse engineering.. and then modifying, no?
Cheers
_________________ ;++JustForDimSim++;
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FPV_GTp |
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hi
spork " Realistically we will never get as smooth shifting as stock, but I think it should be possible to define a set of shifts that work fairly well for one engine/transmission combo, then just make the engine torque adjustable so when someone mods their engine they just put in their new torque curve and the trans re-calibrates itself. " Im sure with all the inputs from the varies sensors a microprocessor of some sort will be able to make the correct and smooth sifting points on the transmission once it is programmed a set of tasks give a example just one of many if cruising down the road from standing still right up to a speed of say 60 kmh , to get the mass of the car moving one will have to press the accelerator a little more the transmission should be in first gear at a pre programmed point when all the conditions are met it shifts into second gear and so forth until its reaches drive the power that's required to achieve this is anything between 10kwatts up to 20kwatts the S5 solenoid can be controlled to make the shift points nice and smooth between gear changes but image for high performance application where the throttle is planted down to the floor then we are talking about different power levels the engine will be producing and generally one uses the transmission in manual mode ie do the selection of the gear changes yourself but there will be guys that are lazy and let the transmission do the changing for them this would be the great benefit for the trans controller and a big test more fluid pressure is required to apply clutch packs and band to hold the power through the transmission these are just a few examples but im sure the system would work if a lot of thought and planning was put into the idea cheers
_________________ WANTED - Complete BTr4 and zf 6hp26 automatic transmission 6 cylinder and V8 transmission(s) suit rebuild? Drop me a PM if you can help would be greatly appreciated - thanks |
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mikejh |
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As Spork said !
Quote: So don't underestimate the difficulty of this project.
Its all very well talking about when the transmission needs to shift but just accomplishing ONE clean shift will be a massive project in itself. As Spork has outlined, there is a huge sequence of events that need to take place - perfectly - to make to box change gears, not to mention the number of variables involved in just driving the vehicle like engine torque, RPM, road speed, ambient temperature, fluid temperature, engine load, limp home modes, lockup control (not that hard), idling engine up when fluid is too hot, running in lock up mode when fluid is too hot, etc etc. Everyone complains about how the standard boxs do stupid things, and shift all wrong etc, and Ford would have thrown thousands of dollars and a team of twenty or more people (full time) at the project of designing their ECU. When a friend and I started designing an engine management system about three years ago, everyone said "controlling an engine is simple". Yeah right ! There are many people that could get an engine running using a scratch built ECU, but to make it run perfectly is a huge undertaking. We have only now got to the point where we can say we are happy with it, after thousands of hours of programming, and thousands of lines of code. I now have a much greater respect for those that design factory systems, and they only have one type of engine/vehicle to design for. Call me pessimistic, but I don't expect BTR control to be any less of a nightmare. If you're not scared now Skywalker - you will be |
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