[Diy_efi] Traction control strategy (solution offered)

[Perry Harrington]

I'm not planning on making any TC devices, but here is how I'd implement it,
I'll give 2 examples.

Example 1:  My 1989 Mustang 5.0 (heh ;).

Since I have SN95 spindles, I'd add the ABS sensor to the front.  For the rear,
rather than futzing with reluctor rings, I'd just use the VSS, it's conveniently
mounted to the driveshaft and monitors the exact same thing (driveshaft speed)
as the Lightning TCS does (they have a reluctor ring on the ring gear in the diff).

Since I have 3 channels, I'd work it out like this:

LF + RF / 2 = F
R           = R

Slip = F/R

If Slip > 2% (.02) Then engage TCS until Slip < 2% in closed loop

Example 2:

FWD Acura.  Use all 4 ABS sensors in this fashion:

LF + RF = F
LR + RR = R

Slip = R/F

Note that the Slip bias is based on driven wheels.

Apply same TCS strategy as above with 2% slip reg.

Both of these methods allow for cornering and can act on open diffs, closed
diffs, and FWD.

As far as the electrical configuration:

An LM339 configured as a zero crossing detector, each output going to an IRQ
input on an MCU.

The MCU maintains the math internal.

The other option is to use 4 timer input capture trigger inputs and write
code to work around the overflow for sitting still.

The A/D approach is simple, but full of unneccesary hardware and possible problems.

A direct digital approach like the OEMs is simpler even.

--Perry

-- 
Perry Harrington             Linux rules all OSes.               APSoft      ()
perry at apsoft dot com 			                 Think Blue. /\

Those who would give up essential liberty to purchase a little temporary safety
deserve neither liberty or safety. Nor, are they likely to end up with either.
                             -- Benjamin Franklin


_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi