TRACTION CONTROL

[Steve]

Scott wrote:


>Just a question about cutting the fuel at WOT:  Couldn't that be very
>very bad for a high cylinder pressure engine?  I know my race engines
>when just a little lean will start to pit the pistons very quickly and a
>supercharged car will just sneeze.  I've seen many Winston Cup cars come
>in puffing after they mis-calculate their mileage or get a little
>greedy.  Maybe that is a totally different situation than taking off
>from a standing start, but it just makes me uneasy running an engine
>lean under full throttle.  Does the fact that you are talking about
>shutting the fuel completely off for those durations mean that no
>residual fuel will be left over from a previous cycle to give it a lean
>condition?  Ease my mind please.
>--

In my earlier post I quoted the SAE paper number for the BOSCH Lamborghini
system that was used on the F1 engine until it was outlawed.  All the top
teams used essentially the same thing.  The amount of residual fuel in the
cylinder is non-combustable.  The issue is the next cycle when the injector
turns on and you now have to 'wet' the port walls and the back of the valve.
This will lean the cycle slightly.  That's why they rotate the injector cut
to avoid drying the walls.


Snipped out of my earlier post:

>There are several good SAE papers on traction control out there.  >One
(942474) is on the BOSCH system for the Chrysler F1 engine.  >They used a
rotating cylinder cut on fuel to control traction.  They >were concerned
with wall wetting issues and crankshaft torsion >vibrations so those were
the 2 biggest concerns that led to fuel cut.  >The ignition cut was ruled
out because of high EGT's with the fuel >buring in the pipes and it wastes
fuel. Retarded timing was ruled out >due to EGT being too high for the
exhaust valves.

Steve