DIY Traction Control

Tue Apr 2 08:53:20 GMT 2002

Once in wheelspin with a healthy v8 20d wasn't hardly enough to stop it.  It
took a 1 in 7 and 1 in 5 cylinder firing defeat strategy.
The trick is stop the wheelspin before it gets out of hand.   At least with
the simple stuff I was working with
Bruce

----- Original Message -----
From: "Perry Harrington" <pedward at apsoft.com>
To: <diy_efi at diy-efi.org>
Sent: Tuesday, March 26, 2002 3:15 AM
Subject: Re: DIY Traction Control

> I was thinking about traction control on my Mustang.  Since I have
> a Crane HI-6 that can pull out 20 degrees via a boost reference (simple
> analog input), you could use that retard to do the same thing commercial
> traction control does.
>
> You would use the abs sensors to read wheelspeed, simply compare the
pulsewidths
> of the front and rear wheels.
>
> Simply retard the ignition based on the percentage difference between the
> sum of the front wheel speeds vs the rear wheels.
>
> --Perry
>
> On Thu, Mar 21, 1996 at 03:08:04PM -0500, Bruce wrote:
> >
> >
> > I'd first tackle things a bit differently.  You way seems to really beat
on
> > the engine.
> > I'd start with a timing and fuel map, that is referenced to TPS, and VSS
(of
> > a none slipping wheel).  It would be just enough timing and fuel to
possibly
> > haz the tires, and then use the Traction Control to fine tune that set
of
> > maps with some feed back.
> >    With a displacement of 1.8L that would seem to be a 4 banger,
dropping
> > one cylinder is going to be like a 30+% drop in power, which is alot
> > Bruce
> >
> >
> >
> >
> >
> > ----- Original Message -----
> > From: "Jorgen Karlsson" <jorgen.m.karlsson at home.se>
> > To: <diy_efi at diy-efi.org>
> > Sent: Thursday, March 14, 2002 6:53 PM
> > Subject: RE: DIY Traction Control
> >
> >
> > > Hi,
> > >
> > > Lets assume that you have a turbo car with no catalytic converter.
> > >
> > > I think that we want to keep the boost as high as possible even when
TC is
> > > doing its job, this would require us to alternate between cutting
sparc
> > and
> > > fuel.
> > >
> > > Cutting spark will limit power and send raw fuel out into the exhaust
> > > manifold where it will ignite, this will cause very high exhaust
> > > temperatures and lots of exhaust energy that drives ther turbine.
> > >
> > > Cutting fuel will limit power and will not provide any energy that
drives
> > > the turbine.
> > >
> > > Changing spark timing would be nice as it can act like something
between a
> > > cut spark and a normal combustion. It will provide some power and a
bit
> > more
> > > exhaust energy to drive the turbine. But lets stay away from that for
now.
> > >
> > >
> > > If we want to do this right we need to know: if the clutch is
released,
> > real
> > > vehicle speed, driven wheel speed, Boost, throttle and exhaust
> > temperature.
> > >
> > > The exhast temperature tell us if we can cut spark without melting the
> > > manifold or the turbine.
> > >
> > > The throttle position can be used to tell the system what boost level
we
> > > want to keep when the TC is working.
> > >
> > > The boost tell us if we need can cut fuel without letting the boost
drop
> > to
> > > much or if we need to dump some fuel to keep the turbo spinning.
> > >
> > >
> > > Example.
> > > Car:
> > > Honda civic FWD, manual, 1.8l, turbo, no cat, lots of power.
> > > Maximum boost 1.2bar gauge, maximum exhast temperature 1800oF.
> > > We want to optimize this car for streetracing on low profile tires,
this
> > > mean that we can let the exhaust gas temperature get as high as 1800oF
and
> > > that we will have our share of traction problems.
> > >
> > > We want to keep the boost above 1.0bar if the EGT permits.
> > >
> > > A two step rev limiter will simplify the starting procedure a lot on a
FWD
> > > dragrace car and that function is best built into the TC box too but
we'll
> > > ignore that for now.
> > >
> > > The TC is not activated until the clutch is released and this occurs
when
> > > the speed is high enough to keep the engine above 5k. Because of the
TC
> > the
> > > throttle is floored until we reach the finish line.
> > >
> > > The front wheels lose traction at once and are spinning 70% faster
then we
> > > want them too, EGT=1300, BOOST=0.5. This tell us that we want to cut
lots
> > of
> > > power, we want more boost and the EGT is very safe. We try cutting 40%
> > power
> > > by running this sequence:
> > > no spark, fire, no spark, fire, fire.
> > >
> > > After a few cycls of this we find:
> > >
> > > 30% wheel spin, Boost 0.8bar, EGT 1350(probably sensor lag.)
> > > Need to decrease power a bit, Boost still to low, EGT still safe.
> > >
> > > We don't want to cut one spark after an other because we pay our own
> > turbos
> > > and are forced to run this sequence (40% of total power):
> > > no spark, fire, no spark, fire, no fuel.
> > >
> > > After a few cycls of this we find:
> > >
> > > 5% wheel spin, Boost 0.9bar, EGT 1400.
> > > Need to increase power a bit, Boost still to low, EGT still safe.
> > > We jump back to the 60% power sequence:
> > > no spark, fire, no spark, fire, fire.
> > >
> > > After a few cycls of this we find:
> > >
> > > 15% wheel spin, Boost 1.1bar, EGT 1450
> > > Power is ok, Boost higher then needed, EGT still safe.
> > > We modify the 60% power sequence:
> > > no spark, fire, no fuel, fire, fire.
> > >
> > > After a few cycls of this we find:
> > >
> > > 15% wheel spin, Boost 1.2bar, EGT 1500
> > > Power is ok, Boost high enough to open the wastegate, EGT still safe.
> > > We modify the 60% power sequence again to limit exhaust energy:
> > > no fuel, fire, no fuel, fire, fire.
> > >
> > >
> > > Depending on the amount of wheel spin compared with the current engine
> > > output we decide the amount of power we want to try next time. The way
we
> > > decrease the power is decided by the boost level unless the exhaust
> > > temperature is to high.
> > >
> > > Power to high>cut more cylinders.
> > >
> > > Power to low> cut less cylinders.
> > >
> > > Low boost> cut more spark and less fuel.
> > >
> > > High boost> cut less spark and more fuel.
> > >
> > > High EGT> cut less spark and more fuel.
> > >
> > >
> > > The software pick the right power level depending on wheel spin and
the
> > > right sequence depending on boost and EGT.
> > > Sequences suitable for a four cylinder engine:
> > >
> > > 80% Power
> > > spark, fire, fire, fire, fire
> > > fuel, fire, fire, fire, fire
> > >
> > > 60% Power
> > > spark, fire, spark, fire, fire
> > > spark, fire, fuel, fire, fire
> > > fuel, fire, fuel, fire, fire
> > >
> > > 40% Power
> > > spark, fire, spark, fire, fuel
> > > spark, fire, fuel , fire, fuel
> > > fuel, fire, fuel, fire, fuel
> > >
> > > 20% Power
> > > spark, fire, spark, fuel, fuel
> > > spark, fire, fuel, fuel, fuel
> > > fuel, fire, fuel, fuel, fuel
> > >
> > >
> > > This system would only need an rpm input to allow it to double as 2
step
> > > revlimiter, launch control, flatshift, ALS and ALS cooldown idle
control.
> > > All of them very cool functions.
> > >
> > > Comments are welcome!
> > >
> > >
> > > Jorgen Karlsson
> > > Gothenburg, Sweden.
> > >
> > >
> > > ----- End of forwarded message from owner-diy_efi at diy-efi.org -----
> >
> --------------------------------------------------------------------------
> > --
> > > To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the
> > quotes)
> > > in the body of a message (not the subject) to
majordomo at lists.diy-efi.org
> > >
> >
> > ----- End of forwarded message from owner-diy_efi at diy-efi.org -----
>
> --------------------------------------------------------------------------
--
> > To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the
quotes)
> > in the body of a message (not the subject) to
majordomo at lists.diy-efi.org
>
> --
> 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
>
> ----- End of forwarded message from owner-diy_efi at diy-efi.org -----
> --------------------------------------------------------------------------
--
> To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the
quotes)
> in the body of a message (not the subject) to majordomo at lists.diy-efi.org
>

----- End of forwarded message from owner-diy_efi at diy-efi.org -----
----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org