Hybrid Car – More Fun with Less Gas

Thinking of getting a prius - Page 2

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Posted by Bob & Holly Wilson on October 20, 2007, 11:35 am

During the engine warm-up, the car runs at about twice the rate of fuel
consumption than after warm-up. The trigger appears to be 70C. The North
American Prius has a hot water thermos to accelerate warm-up but this is
missing from the Asian and Eurpoean Prius.

The block heater brings the engine block to a temperature closer to 70C,
which means the engine controller goes into higher efficiency, lower
fuel rate burns, than when coold. This shortens the warm-up cycle and
reduces warm-up fuel burn.

In North America, we can use a block heater that fits in a receptical
located behiind the engine, close to the firewall. We have 120VAC power
for this 450W heater element. In other countries with different power,
they will need either an interface transformer or a block heater that
works on their power grid.

If you look at your mileage graph, you'll notice the first 1-3 bars
usually are ascending and the the milege levels out. The engine block
heater reduces the number and lengthens (improves) the warm-up mileage.

Bob Wilson

Posted by Doug on October 20, 2007, 2:00 pm

I live in the Midwest USA and have driven through blizzard-like
conditions and severe thunderstorms in my 2005 Prius with no problems
while driving below the speed limit.

Posted by Alan on October 20, 2007, 11:31 pm

Thanks guys for your help in responding to my initial question.
 I managed to get a longer test drive today and was even more impressed.
 One other thing I wanted to check up on ,which the dealer was unable to
answer was how real is the possibility of the battery completely discharging
when going up hilly roads and the car reducing its speed significantly
because it only has the petrol engine left. I am asking the question because
the NW of Scotland where I live does have some rather steep winding roads up
the hillsides. I know I am only talking about sea level to about 1500 feet
which is small by US standards  but some of these are roads are 7 to 10
miles before they reach the highest point. Is this an issue or am I worrying
unnecessarily? The Dealer is situated on the east of the country where the
land somewhat flatter so could not answer this.
Thanks again.

Posted by Elmo P. Shagnasty on October 21, 2007, 11:11 am

OK, listen up.  I'll say this once:

the car is a gasoline car.  Period.  It runs on gasoline.  The only
source of energy that you put into the car is gasoline.  Everything in
the car is powered by gasoline.

It is NOT an electric car.  At all.

It is a highly engineered gasoline car, with some goodies to maximize
the use of that gasoline--in other words, designed to extract as much
energy out of that gasoline as is practical and reduce waste of energy.  
One--ONE--of those goodies is a battery to store gasoline energy that
would otherwise have gone to waste.

The mechanism for storing/releasing this energy is managed not at ALL by
the end user, but by a computer.  The computer takes its cues from the
driver's gas pedal use and the car's speed and acceleration.  It also
takes its cues from the state of the battery.

The computer NEVER lets the battery get below 40% charge and NEVER lets
the battery get above 80% charge.  This is designed specifically to
protect the battery and maximize its life.

Thus, the battery will NEVER discharge completely.

The system--yes, it's a system, not just an engine--is always balancing
the driver's needs with the battery's needs, and is figuring out where
to apportion the gasoline's energy at any given moment.

You will never, ever reduce speed to any degree going up hilly roads.  
The system is designed to give you everything it's designed to give you
at any time.

Posted by Piper on October 21, 2007, 11:13 am


I'm not technical at all, and I'm sure one of these guys will tell you
why you don't have to worry about this.  All I know is that my Prius
can manage hills and mountains like any other car.  Better, in fact,
than some I've had.  Besides, I don't think the batteries ever
completely discharge.  The engine is constantly recharging them.
That's the beauty of "hybrid".

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