Fuel injection plugs

[Raymond C Drouillard]

On Sun, 02 May 1999 01:46:50 -0400 James Ballenger <jballeng at vt.edu>
writes:
>
>
>Raymond C Drouillard wrote:
>
>> CHANGING THE GEARING CHANGES THE ENGINE SPEED!  THAT IS THE WHOLE
POINT!
>
>    Shifting gears changes the engine speed.  The point is if we didnt
need
>to shift and had a smooth transition through the whole range we could
keep
>the engine rpm constant.  When you are in first gear you rev up the
engine in
>a static gear and then shift it to start reving in a new static gear. 
You
>could make the gearing dynamic, a cvt, and be able to keep the engine
speed
>constant.
>
>
>> A CVT doesn't change the power (besides the ordinary efficiency
losses).
>> If you attempt to reduce the torque to the drive wheels by changing
the
>> gear ratio, you will either slow down the engine or speed up the
vehicle.
>>
>> An unthrottled engine running at a specific speed (max torque, for
>> example) is going to put out a specific amount of power.  If this is
more
>> power than is required to maintain the desired cruise speed, the
vehicle
>> will speed up.
>
>    A cvt wouldnt change the effective torque at the crank, but would
modify
>it at the drive wheels.  What happens if you keep your rpm constant and
shift
>from 1st to 4th?  You can keep the load on the engine constant and
therefore
>the rpm constant by changing the gear ratio.   I suppose a problem
occurs
>when there is little load on the engine, but the could be countered by
an
>insanely low (numerically) gear keeping in mind I am discussing a
perfect cvt
>with infinite range.
>
>> If you want to prevent this without throttling - that is, if you want
to
>> maintain the same cruise speed without throttling, you will need to
>> change the gear ratio.  Assuming that you don't speed up, the engine
will
>> HAVE to slow down.
>
>You don't have to slow the engine down, you reduce the transmission
ratio.
>
>James Ballenger
>

James,

Please find a textbook or go to the library and look up the formulas that
relate torque, speed, and power.  Also, look up the formulas that relate
gear ratio, torque multiplication, and speed multiplication.

I have memorized them long ago.

A lot of what you are saying flys directly in the face of those
mathematical relationships.  I have tried very patiently to explain how
such a system will work, but something just isn't working.

After you have memorized those formulas, reread the messages.  If you do
this, enlightenment will come.

Hint:
If you run an engine at WOT, it will produce a specific amount of power
at a specific speed.  If this power is more than necessary to overcome
friction, the vehicle WILL speed up.  It makes no difference whether you
are using a stepped or continuously variable transmission.

Adding a control system to a CVT will succeed in keeping the engine speed
stady, but the vehicle will STILL speed up.

It's simple physics.  Look up the formulas and try to apply them.


Ray Drouillard, BSEE

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