Auto gearbox modification

[The Lovely Boyo]

"Apache...The only man to stall a Auto"

LOL - I was trying to imagine what it would be like too!

[Apache]

Which is why (further back in the thread - see post 12) I said that 'brakes', and the signals for 1st and 2nd gear will be logically OR'd in my controller design so stopping in lockup is not possible.

First I need to know why the box doesn't seem to change down in lockup. You chaps dont know?

[BUSHWHACKER]

Which is why (further back in the thread - see post 12) I said that 'brakes', and the signals for 1st and 2nd gear will be logically OR'd in my controller design so stopping in lockup is not possible.

First I need to know why the box doesn't seem to change down in lockup. You chaps dont know?

Evidently, I don't.

[The Lovely Boyo]

First I need to know why the box doesn't seem to change down in lockup. You chaps dont know?

I've mailed a write up on the toyota auto box to your surf sticker inbox

see if that has any info thats of use.

[Apache]

Thanks And, looks like interesting reading.

This is first draft of control / failsafe circuitry. Comments anyone? Matt F, i'm looking at you! PLEASE NOTE - resistors connected to inputs of OR gate are connected to 0v, not +12v volts as shown.




Single momentary pushbutton for lock / unlock via 4027 flipflop used as a latch. I'm using the active low O/P as I have then NOR'd the O/P so only a zero on each I/P will allow the operation of manual lockup.

This means I can OR imputs from brakes, solenoid 1 (only active during 1st and 2nd gear) and anything else which you'd like to disable lockup, and feed the output (normally '0') to the other input of the NOR.

Therefore a '1' from the latch (manual disengage of lockup) or any input to the OR gate will cause cancellation of lockup.

Also used the normally closed side of the relayfor the ECU (failsafe), and I *think* the latches start position should be with a '1' on Q bar, so lockup should be off initially. Even if it isn't, foot on the brake to start the engine will cancel lockup, and if lockup is on, there'll be a light in the switch so you can cancel it manually before selecting 'Drive'

Anything else? Any glaring bloopers?

[gwh200]

if you dont have a foot on the brake,and/or you fail to note the illuminated light,will it just not start,until the correct procedure is adhered to ??

just like when you try and start in gear ?

[Apache]

I dunno. I'm not sure if the ECU is smart enough.

I dont think it will start in lockup, as I think the latch will always power up with Q bar high.

I'll do a bit more looking into latches and see if there is a definitive way of ensuring that.

[The Lovely Boyo]

Apache - what have you started ????

OK - I've been doing some testing of my own on some quiet, flat roads this afternoon.

Drive around with the O/D off. You will find the shifts are quite pronounced/definite (accelerate at about 2200rpm, don't boher with the ECT). The convertor will still lock up, mine does it at about 45 mph.

Now drive around with the O/D on. It feels like the box now has about 5 or 6 gears. I think the ECU is using the O/D to 'slur' the changes. Much more difficult to check whats going on. At constant revs (again 2200) box almost feels like a CVT!!!!!

There's a lot more going on than you'd think.

[Apache]

Still early days re. the design Andy, but that is interesting. I'll go the long way home tonight and try that.

I definitely need to sort out an indication of what solenoids are operating and when. I feel some LEDs coming on!

Now I'm into this, I wont be happy until I've got a fully switchable manual / auto box with selectable lockup!

I wonder whether the box changes normally without OD on and with lockup selected - I think you may have put your finger on something there because I reckon with OD on, selecting lockup manually forces the box into OD too...

'Blizzard' seems to understand the mechanical side of the autobox pretty well. Wonder if he can shed some light on this?

[TonyN]

First I need to know why the box doesn't seem to change down in lockup. You chaps dont know?

Like the abuse earlier, if its locked up, you're gonna get get some nasty-ass clunkly gearchanges.

[Apache]

Like the abuse earlier, if its locked up, you're gonna get get some nasty-ass clunkly gearchanges.

Only in the lower gears I would imagine.

If that does happen, I need to think about an automatic momentary deselection of lockup during up and down changes.

[KERRSURF]

are you re-designing the ECU then.

[Apache]

Hehe.

All I'm aiming to do is make something useful, but something numpty-proof which will avoid stuffing the box - which needs more than a single switch.

Andy, tried with OD off on the way home and lockup at any speed forces (what feels like) 3rd gear. I think the ECU must push the box into the highest gear when it detects lockup - this means I can have high geared manual by using the OD button to select 3 - 4 (OD). Obviously, this isn't totally satisfactory, but it aint a bad start for what *I* want!

Incidentally Andy, the changes with OD off are as smooth as with OD on. What box is fitted to the 2.4s?

Next step is to instrument the ECU so I can see the decisions its making in real time. This will probably amount to a bit of veroboard full of LEDs labelled up with their function.

Its really getting interesting!

[gwh200]

Hehe.

All I'm aiming to do is make something useful, but something numpty-proof which will avoid stuffing the box - which needs more than a single switch.

Andy, tried with OD off on the way home and lockup at any speed forces (what feels like) 3rd gear. I think the ECU must push the box into the highest gear when it detects lockup - this means I can have high geared manual by using the OD button to select 3 - 4 (OD). Obviously, this isn't totally satisfactory, but it aint a bad start for what *I* want!

Incidentally Andy, the changes with OD off are as smooth as with OD on. What box is fitted to the 2.4s?

Next step is to instrument the ECU so I can see the decisions its making in real time. This will probably amount to a bit of veroboard full of LEDs labelled up with their function.

Its really getting interesting!

is there a fundamental difference bewteen the 2.4 and 3.0 liter box ??




geek

[The Lovely Boyo]

I'm pretty sure that most auto Surfs were fitted with the A340F box.

Some had the built in transfer case which was the A340H (I think, can't be bothered to look).

Andy, did you get that pdf about the Toyota ECT?