TRACTION CONTROL

[Raymond C Drouillard]

A friend of mine has a Camaro F-body.  It has a defeatable traction
control that actually uses a servo of some sort to push the accellerater
up.  He tells me that he can feel it kick back.  He (like many owners of
such cars) likes to press the "defeat" button and burn rubber.

One of the German car companies (BMW, I think) uses a traction control
system to help control skidding in slippery (winter, mostly) conditions.

Mercedes uses a brake-actuated traction control system (part of ABS, I
would assume)) to slow down a wheel that loses traction.  This is for
off-road use.

Jeep mechanically does something similar in the transfer case and in each
differential with its Quadratrack II (tm) system.  Instead of stopping
one of the wheels, it employs a cluch between the axles (in the axle) or
between the driveshafts (in the transfer case).  When a difference in
speed is detected, the cluch is engaged, limiting the slip or locking the
axle or transfer case.

If you want to simply limit the power, you might want to consider
blocking the injecter pulses rather than the ignition pulses.  If you are
using multipoint injection, you can selectively give any cylinder a
breath of pure air rather than air-fuel mixture.  Do this every seventh,
fifth, or third pulse as you described, and you'll have the same effect
without burdening the cat with lots of raw fuel.

My Holley Pro-Jection system has a rev-limiter built in.  It works by
cutting the fuel when the speed gets too high (I have it set to 5300, I
think).  I have demonstrated it a few times.  It works well.  It just
sort of bounces off the top of the limit and doesn't tend to smell up the
place.

Ray Drouillard


On Wed, 11 Nov 1998 19:34:54 -0500 "Bruce Plecan" <nacelp at bright.net>
writes:
>
>-----Original Message-----
>From: Stuart Bunning <stuart at kenelec.com.au>
>To: diy_efi at efi332.eng.ohio-state.edu 
><diy_efi at efi332.eng.ohio-state.edu>
>Date: Wednesday, November 11, 1998 6:27 PM
>Subject: TRACTION CONTROL
>
>
>My "idea" was using a sudden change in VSS.  Ran some 555's for
generating
>pulses on +and - transititions, to charge two caps.  Then a voltage
divide
>by 10.  To drop the power I did stage one at losing every 7th ignition
>pulse. then very 5th, then 3rd.Problem with my design was totally 
>dependent
>on temp to work.
>  Also tried using a MSD Multistep-Retard to back the timing up has
three
>stages, and you can add them together.
>
>>
>>I am wanting to do a DIY traction control.
>>Does anyone know if OEM systems use ABS/apply brakes or >retard timing
in
>the event of lost traction..
>>If it was retard timing maybe simulating a KNOCK would be a easy >way
to
>reduce power and get traction back. The only problem i >would see here
is
>how quickly doesn the ECU ( 808/165 ) give me >back full timing once a
knock
>has gone away.
>
>The decay rate is in the memcal, as well as the timing limits.
>
>Best idea I've seen is incorporating a front wheel speed sensor,
>and comparing it to the rears, or driveshaft.
>Bruce
>
>>Thanks in advance....
>>Best Regards,
>>STUART BUNNING
>>SALES ENGINEER
>>KENELEC PTY LTD
>>23-25 REDLAND DRIVE
>>MITCHAM VICTORIA 3132
>>AUSTRALIA
> stuart at kenelec.com.au
>>WEB:    http://www.kenelec.com.au/
>>
>
>

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