TOD controller - knob, wheel, or buttons?

[orion]

the rear wheels are not controlled by the TOD at all. the front "shares" torque with the rear. so 100% the the front is just all the torque it can receive, not no rear torque. I like a simple 4 way split, I can't see why I'd need 67.4% the the front

[VehiGAZ]

I can't see why I'd need 67.4% the the front

That's a really good point. It's nice to have choices, but what would you do with all those intermediate choices? I mean, what driving conditions really demand only a 25%-75% split and nothing else?

The only "forced" split ratio I am interested in is 50%-50% F-R (or 100% engagement of the front axle - however you want to look at it). That would be the equivalent of full-time 4WD-hi, which we don't have. I find the ToD system to be at a loss on smooth dirt or somewhat snowy roads when there is enough traction loss to confuse the ToD system (that constant on-off-on-off-on-off). That's when I find the system lacking and I want a locked 50%-50% split. When the conditions get worse, you go to 4WD low range and slow down. If they improve, regular ToD operation is fine.

I would also suggest to include a 0% front-axle engagement setting or a circuit that cuts power to the ToD entirely in order to achieve RWD (when used with unlocking front hubs). The ToD clutch pack is designed to operate with some slippage constantly, so I am not worried about trashing it with a 0% setting or cutting the power.

[taylorRichie]

I figure the intermediate choices may come in handy, I don't know... With winter driving I'm not sure what split will give the best control between over and understeer. Basically it's not an issue to add it so why not? The only expense would come if people wanted to have infinite control 0-100%. But I didn't think that was necessary.

We can add it, but it will be with a strict warning, I really don't want to be responsible for damage to people's vehicles, and MBEACH really cautioned us against this.

[VehiGAZ]

With winter driving I'm not sure what split will give the best control between over and understeer.

Good point!! I like the balance when in 4WD-low, but who knows what will feel best at higher speeds in 4WD-high.

Normal ToD operation is somewhere around 90%-10% to 85%-15%, so there's not much point in doing a 75%-25% on top of that. Maybe 66%-33% and 50%-50% would be good increments. If I had my druthers, it would be these choices:

ToD Off (100%-0%)
ToD On (85%-15% nominal)
Locked 66%-33%
Locked 50%-50%

[twistedsymphony]

I'd be happy to help in the electronics department if it's needed... I do lots of custom circuits in my spare time (Meche by trade EE by hobie )

as for the splits...

if you're going to split it PERFECTLY 4 ways you're looking at
5% - 20% - 35% - 50% that a clean 15% change with every "click"
however I get the impression most people are really only looking for this:
5% - AUTO - 50% where "auto" is simply letting the TOD do its thing, 5% gives you the best fuel eco and 50% gives you the best traction.

if you wanted it to be really snazzy you could go with "wheel" type adjuster (think like the scroll wheel on your mouse but tighter to hold itself in place) that "clicks" on both ends... meaning wheel it all the way down and click for 5%, wheel it all the way up and click for 50% and then infinite adjustment in the middle... you could have a 2nd switch that would allow you to switch between TOD control and whatever you have the wheel set to.

[taylorRichie]

Thanks for the offer, and insight.

We're thinking 4 positions just as you said, and more than likely it'll be a 5 position dial. This is the where we haven't fully decided.

5-20-35-50-TOD

We have all the firmware and circuitry done, just waiting for another project to wrap before getting the boards shot.

[twistedsymphony]

sounds like you're using an MCU... are you going PIC or AVR... or something else altogether?