Hybrid Car – More Fun with Less Gas

What is the "optimum driving style" for mpg?

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Posted by Lon on April 22, 2008, 6:11 pm
 
My '04, purchased in late '03, has about 52k miles on it
and has averaged about 43mpg since new - less in winter,
more in summer. I'm in S Calif, so "winter" is a period
on the calendar rather than a season. 90% of the time
there's just me aboard, so I benefit from the HOV
sticker! The tires are inflated properly (+2psi) and the
wheels are aligned.

I envy those who consistently report 10-20% better
mileage than I have attained, and suspect that the
deficiency is in my driving.

My "technique" is to stay off the brakes, doing a lot of
coasting and careening around corners, on the theory
that neither regen nor friction braking are as good as
using kinetic energy to continue moving. That means I
must take my foot off the gas as soon as it becomes
evident that the car will have to stop.

What else can I do to improve mileage?

Thanks,

Lon Ranger

Posted by Mr. G on April 22, 2008, 11:10 pm
 
(angry@none.com) says...

I think the most important key is to keep your speed as steady as
possible, neither accelerating nor decelerating quickly (light on the
gas, light on the brake.)  It isn't necessary to drive very slowly, and
in fact it seems that moderate acceleration yields better results than
driving like a tortoise.  If you see a that you need to slow/stop for
traffic, a traffic light, etc. start to slow as soon as possible.  If
you can keep moving, so the traffic starts moving before you catch up to
it, is the ideal.  On the highway slowing down a bit, say from 75 to 65,
will make a difference.

As far as careening around corners, I think you'd be better off slowing
down a bit, allowing the dynamic braking to recover some energy.  Yes, I
know a lot of folks will say regen isn't close to 100% efficient, but it
doesn't have to be.  When you turn, you're losing energy to a number of
forces.  A change in direction is a form of positive acceleration, which
takes energy.  And if you have any wheel slip, that's also wasted energy
(not to mention the wear on your tires.)  So slow down enough that you
can take the corner easily, then slowly accelerate again after the
corner.

My 2

Posted by Tomes on April 23, 2008, 1:30 am
 "Lon" ...

Hi Lon,
Here is what I do that I believe gets me more MPG.  As much as I can I try
to get it to run in stealth mode at all speeds.  All speeds on flat or
downward slopes.  To do this I use what I call PriusFoot.  I get up to my
speed and then lift the foot off of the pedal for an instant.  This shuts
the motor off.  Then I lightly press on the gas pedal again only so much
that it engages the battery drive, but not the engine.

This takes a trained foot and it took me a bit to get it reliably right.  I
do it without thinking now.

I do it as much as I can.  I am almost always generating more electricity
than I use, so I try to use as much as I can.
Tomes


Posted by Lon on April 23, 2008, 4:15 pm
 Tomes wrote:

I can "force" electric drive in either of two ways. For
example, I installed a red LED that illuminates only
when the fuel pump is ON. I could add a switch to the
circuit that powers that pump, but the total energy in
the traction battery is about equivalent to a martini
glass full of gasoline. And, of course, there's Pin 27.

I'll discover that "Priusfoot" thing today and see if
it's feasible without becoming an obstacle to others.

Thanks!

Hi yo, Silver!

Posted by Chas Gill on April 23, 2008, 4:36 pm
 

I'm really not sure that it is a good idea to "force" the electric drive.
The car has several primary directives built into it's management systems
and one of the most important (so I read) is to manage the battery for long
life.  I'm not at all convinced that dragging every spare watt out of it
(deep cycling) on a regular basis will do it a lot of good.  Why not just
drive the thing and let it look after itself, as designed.  Early battery
failure is likely to be the alternative outcome.

Chas



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