Hybrid Car – More Fun with Less Gas

Exhaust visible with car at stop light

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Posted by kaplan3jiim on March 22, 2008, 6:29 pm
Not an owner, but considering a Prius and have test driven one.  My
understanding is that the gasoline engine is not running at idle, but
this morning (a humid) morning, I pulled up besides a Prius at a stop
light and exhaust gases were obviously pouring out of the tail pipe.
How can this be? Assuming a Prius buyer is not do dumb as to be
sitting at a light revving the engine.

Posted by Reed on March 22, 2008, 6:41 pm
kaplan3jiim@example.com wrote:

Not an owner either, but maybe the battery (batteries ?) needed
charging ??

BTW, what happens if driver sets the heater (or A/C) to max ? Will gas
engine run as needed ???

Posted by Chas Gill on March 22, 2008, 7:00 pm

The gas engine will run under many specific circumstances but, when the car
is stationary, chiefly when (a) The cabin needs heat (b) the car has just
been started and the catalytic converter needs to be quickly brought up to
operational temperature and (c) the battery needs charging.

It is not possible to "rev" a Prius engine.  The accelerator pedal is
precisely that - it makes the car go.  It does NOT do this by varying engine
throttle, but by a complex combination of activities that cause the electric
motor to move the car, plus the gas motor - if needed.  "Blipping" the
throttle on a Prius has no effect whatsoever on engine revs when the car is
in Neutral.  This is unexpected and somewhat bizarre behaviour!

If the heater is set to max the engine will run until there is enough heat
in the engine coolant to provide sufficient heat to the cabin heater to
achieve the max temperature.  In practice I think this means that it will
run most of the time when the heater setting is max.  Oh, and by the way,
when it is the cabin gets VERY hot!.

I speak not as an expert but as an owner.



Posted by Tomes on March 23, 2008, 1:09 am
 "Chas Gill" ...

Yep, this pretty much says what it is.

Posted by kaplan3jiim on March 23, 2008, 6:49 pm
 On Sat, 22 Mar 2008 19:00:58 -0000, "Chas Gill"

Thanks for the clarification Chas and others.


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