automatic transmission

[dribach]

i'm trying to design an automatic shifter for a manual transmission car, using pneumatics and based off of rpm and speed readings. i can do the pneumatics. that's just simple valve controls, and i can program pretty well, but i'm not to experienced in electronics. i'm looking at using the atmel atmega128L or something similar. if anybody has any experience working with atmel microcontrollers, your wisdom would be very helpful. any advice whatsoever from anybody is greatly appreciated. thanks

[Chris Smith]

Put a torque converter in instead of a manual clutch, and make it even easier? <p>The Citroen GS [Maserati motor] also had a Electric disengage clutch against the back drop of a torque convertor, and had real a winner. Just touch the shift lever and it disengages.

[josmith]

Can't help you with the processor.
Sounds like you have an interesting challenge considering that the auto manufacturers haven't solved all the issue involved in controlling a transmission.
Good luck and give us a progress report.

[Donald S. Lambert]

Didn't the Hudson have an automatic shift deal that was vacuum operated. You could do automatically or manually if a remember right. A fellow emplyee had one that he took the automatic feature off because it didn't work right. Guessing that it was a late 1940's to early 1950's model.Possibly late than that. Greybie

[russlk]

I had a 1952 Hudson Hornet, great car! The transmission was regular hydramatic. It had an unique feature: The foot brake was linked to the emergency brake, so if the hydraulic brakes failed, the emergency brake took over. Too bad no one uses that safety feature today.

[Chris Smith]

Joesmith.......the world solved it 50 years ago,..... we just resist?

[Bernius1]

$.02 ; How will you keep throttle control ? If you read on GM's EFI control, you'll find how they get tach. & veh.speed sensed, and throttle position. A "Standard/Blue Streak Emissions Parts Illustration" catalog will be very helpful. Don't waste any time with NAPA knuckleheads. If I find a link, I'll post it. ALSO, call your local Federal-Mogul / National Seal distributor. They make hydraulic throw-out bearings which obviate the clutch fork & linkage. For shift control, maybe a rev-limiter output to some flip-flops to upshift. Remember, engine loading is read by manifold vacuum. Hi-vac, down-shift, lo-vac, up-shift. Good luck.

[Bernius1]

it's standard motor parts . Only a home page, but REQUEST THE ILLUSTRATED FUEL SYSTEMS CATALOG ! You guys doing PIC control in harsh environments will also benefit. Most EFI sensors balance a resistive change against a 5V reference, all pre-wired.

[dribach]

wow... i'm really impressed with the number and quality of these responses. i plan to make the clutch pneumatic, because i still want to be able to drive it like a standard manual when i want. russ, i like that brake idea, i might add that feature later if i get around to it. no_vice, i think you are the most helpful so far... i plan to disconnect the gas pedal from the throttle, then put a linear position sensor on the pedal and probably a solenoid (with PWM) or maybe a servo on the throttle. that way everything is controlled by the chip. i was definitely not aware of the manifold vacuum technique, i was wondering how that could be determined. thank all of you for your comments, this is awesome.

[josmith]

It seems that things went downhill when converter clutches were added as an economy measure. When the converter is unclutched it makes the shift points less critical. When the converter is locked it becomes more like a manual transmission with one big exception. A driver can anticipate road conditions and shift when necessary or in some cases ride out a short grade without shifting. The transmission can only see load and shift accordingly and often unnecessarily.
Someday they may make a GPS controlled transmission that knows the road.<p>[ September 11, 2003: Message edited by: josmith ]</p>

[dribach]

hmmm... good idea