Accel enrichment

[Raymond C Drouillard]

On Mon, 23 Mar 1998 21:49:27 -0600 Joe Boucher <jboucher at ctelcom.net>
writes:

<snip>

>>When you open the throttle, a whole bunch of air rushes in.  As the
>>pressure equalizes, the air is still moving.  The inertia of the fast
>>moving column of air "rams" more air in.  This effect is used to
increase
>>low-end torque in an engine.  An engine designed for low-end torque
will
>>have narrow passages in the intanke and exhaust manifolds.  This
>>increases the velocity of the gas.
>
>I agree that has some effect, but the increase in pressure over the new
>steady state value lasts for as long as the vehicle accelerates.  The
>rushing in effect is almost immediate.  The only thing that comes to
mind
>is possibly the accelerating piston speed in some way causes an increase
in
>the flow rate.

When I give an automobile engine partial throttle, the manifold pressure
goes up.  As the engine speed increases, the pressure starts to drop
because more gas is being pumped out of the manifold.  If I hold that
throttle position long enough, equalibrium will be reached.  The engine
will be producing exactly the amount of power needed to keep it moving at
that speed.  In that case, the pressure rises suddenly, then slowly
decreases until equalibrium is reached.

If I reduce the opening before equalibrium us reached (I am going as fast
as I want [dare] to go), the manifold pressure will suddenly rise when I
increase the throttle opening, slowly decrease, then decrease suddenly
when I partially close the throttle in order to maintain speed.

>Joe Boucher
>'70 RS/SS Camaro  '81 TBI Suburban


Ray Drouillard

_____________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]