2006 Highlander Hybrid: Does yours do this?

"bicycle6228" <tomdempster at comcast dot net> wrote in message
news:9_udnUGjuP1xuRLYnZ2dnUVZ_oGlnZ2d@. ..
> Driving around town,
> -on flat & level terrain
> -with only the driver; no passengers
> -with no cargo
> -when not in any terrible rush:
> ...if the throttle is opened a VERY small amount, the vehicle runs on
> battery and the gas engine does not start, which is GREAT!
>
> HOWEVER:
> If the trottle is opened just slightly more than a small amount, the gas
> engine starts, when there is no pressing need to do so.
>
> I drive _very_ leasurly, coast to red lights, accelerate slowly, never
> exceed the speed limit, and yet the vehicle still falls short of the
> advertised fuel economy.
>
> Is the vehicle designed to needlessly start the gas engine, consuming more
> fuel than necessary, or is mine malfunctioning?
> How can I determine whether my vehicle is performing as intended by the
> manufacturer, in terms of the hybrid system's behavior with regard to gas
> vs. battery power usage?
>
I remember a report on the Prius that said coasting to a stop does not
recover much energy. It went on to say that the most efficient recovery of
energy happens when the motor is generating about 60 amperes, which
corresponds to pretty heavy braking. Of course, with passengers in the car,
heavy braking won't be treated with kindness, and waiting until the last 20
ft to put on the brakes might be courting disaster. But say you're on a
freeway off ramp from driving 70 mph and there's nobody following you - -
then you might hit the brakes and bring your speed down to 25 mph in a
fairly short distance, like 100 ft or so. Then you might find the engine
willing to let the electric motor run a while before starting up - -
especially if you can put it in cruise control at 34 mph for a while. At
least that's how my Prius behaves.

bicycle6228 <tomdempster at comcast dot net> wrote:
>
> If the trottle is opened just slightly more than a small amount,
> the gas engine starts, when there is no pressing need to do so.

As Ray O said, this is to charge the battery.
But you have a point -- it would be nice to have a setting for
"do not use gasoline engine until notified otherwise."

> I drive _very_ leisurly, coast to red lights, accelerate slowly,
> never exceed the speed limit, and yet the vehicle still falls short of
> the advertised fuel economy.

A friend got only 24 mph on a long trip from Texas to California.
The Highlander Hybrid is more overrated than the Prius for EPA mileage!
Consumer Reports got 16/28 in their testing, which, it should be noted,
is better than the EPA number for highway mileage.

The Highlander is not very aerodynamic and weighs over 4400 pounds.

Andrew Stephenson <ames@deltrak.> wrote:
>
> In an earlier post (months ago), I described experiments done on
> my UK-spec Prius T4, which comes with an "EV" (Electric Vehicle)
> button. With the current battery design, you don't get what any
> normal driver would regard as a useful open-road range; it's for
> pottering about in places where exhaust fumes would be disliked.

Thanks a lot-- I found (what I think is) the thread from September.
Interesting that when your battery gets 3/8-charged, the hybrid system
started up the gasoline engine. I wonder if there's something magic
about 3/8 charge? I always thought NiMH batteries could go near 0%
without damage. Many Lithium-ion batteries are damaged reaching 0%.

The UK-spec Prius T4 "EV" mode would be useful in a parking garage.

I suspect if you had a plug-in battery charger to make the battery
start out full, EV might be useful for more than 2 kilometers.

On 28 Dec 2006 18:11:27 -0800, Bill Tuthill <ccreekinm>
wrote:
>Andrew Stephenson <ames@deltrak.> wrote:

>> In an earlier post (months ago), I described experiments done on
>> my UK-spec Prius T4, which comes with an "EV" (Electric Vehicle)
>> button. With the current battery design, you don't get what any
>> normal driver would regard as a useful open-road range; it's for
>> pottering about in places where exhaust fumes would be disliked.
>
>Thanks a lot-- I found (what I think is) the thread from September.
>Interesting that when your battery gets 3/8-charged, the hybrid system
>started up the gasoline engine. I wonder if there's something magic
>about 3/8 charge? I always thought NiMH batteries could go near 0%
>without damage. Many Lithium-ion batteries are damaged reaching 0%.

Great theory, except for one teensy-weensy teeny tiny problem...
Let the HV battery pack drain down to zero with the engine still off,
and you are stuck. Even though it may not damage the battery pack.

You need the HV Battery to start the gasoline engine, it doesn't
have a 12V starter motor. And you want to stop discharging it at 3/8
on the off chance that the computer is being a *bit* too optimistic
about the battery charge level, leave a cushion.

My Norelco razor is starting to do that because the battery pack is
getting old, it counts the charge down to around "10 minutes left",
and then it suddenly stops dead. (The display has been recalibrating
lower after each charging, but it hasn't caught up with reality yet.)

If that was the Prius starting battery you'd be walking.

--<< Bruce >>--