[Guest]

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?

 

[Guest]

"bicycle6228" <tomdempster at comcast dot net> wrote in message
news:[email protected]
> 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?
>

The vehicle is not designed to needlessly start the gas engine, but it is
designed to start the gas engine if the battery's state of charge falls
below the optimal range or if load on the drivetrain exceeds a certain
amount. The vehicle's propulsion is supplied by a combination of the
electric and internal combustion motors. If the rate of acceleration is
more than the electric motors can provide, the internal combustion motor
will kick in.

Some accessories draw more power and deplete the battery more quickly, like
the air conditioner (including the front defogger), rear defogger,
headlamps, wipers, blowers.

The dealer can plug in a diagnostic scanner to check the hybrid system's
operation, but it sounds like yours is functioning properly.
--

Ray O
(correct punctuation to reply)

 

[Guest]

"bicycle6228" <tomdempster at comcast dot net> wrote in message
news:[email protected]
> 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.

 

[Guest]

Chuck Olson <[email protected]> wrote:
>
> 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.

Chuck, do you ever put the transmission in B (brake) to recover energy?
I am starting to experiment with it, but haven't drawn any conclusions yet.
Here is a relatively good article on improving Prius mileage, most of which
probably applies to the Highlander Hybrid.

http://hybridcars.com/gas-saving-tips/maximizing-mileage-toyota-prius.html

And here is a not-so-good article on pulse and glide, the method by which
some drivers got 100 mpg, probably at 35-40 mph on a closed track.

http://hybridcars.about.com/od/ownership/a/pulseandglide.htm

Seems like putting the transmission in N (neutral) is the same as gliding
by feathering the accelerator, but some advice columns on the internet
say to avoid using N.

 

[Guest]

In article <[email protected]> [email protected] "Bill
Tuthill" writes:

> [...] do you ever put the transmission in B (brake) to recover
> energy? [...]

AFAIK, it's actually "B(attery)", though a lot of people think as
you do. I use it only occasionally; on the whole my Prius does a
good job of maintaining its charge ("B" is for charging where you
the driver know better what the landscape ahead will be like) and
handling the braking. However, I try not to brake hard unless it
is necessary: partly for the same reasons one tries not to in any
vehicle; partly to encourage the car to bank the energy as charge
in the battery, not waste it as heat in the brake pads.
--
Andrew Stephenson

 

[Guest]

In article <[email protected]> [email protected] "Bill
Tuthill" writes:

> Seems like putting the transmission in N (neutral) is the same
> as gliding by feathering the accelerator, but some advice
> columns on the internet say to avoid using N.

Sorry, forgot to add this to my other post. IIRC, the manual too
advises against use of N(eutral). In practice, it is not needed.
As you say, careful pressure on the accelerator (and oddly on the
brake, too) puts the car into neutral (depending on how anxiously
the charging system is watching the battery condition -- when the
charge needs topping, finding the pedal's neutral setting is much
trickier).
--
Andrew Stephenson

 

[Guest]

Andrew Stephenson <[email protected]> wrote:
>
>> Seems like putting the transmission in N (neutral) is the same
>> as gliding by feathering the accelerator...
>
> IIRC, the manual advises against use of N(eutral). In practice,
> it is not needed.

I've spotted several factual errors in the manual, many probably
the result of copy 'n' paste from manuals for non-hybrid Toyotas.
I've also spotted at least 20 grammatical errors, but I read Usenet
so I'm used to that type of thing. ;-}

Observation indicates that the best mileage is produced in one of
two conditions: 1) in accelerator glide or Neutral; 2) when operating
exclusively on electric motor at < 40 mph with battery fully charged
(green not blue bars to the top).

In other words, I see no reason not to use Neutral. The only problem
is that the '07 Prius transmission won't go from N into Battery/Brake
without first going into Drive, so at the top of a steep hill, a quick
double-shift is necessary if I want to save the brake pads.

Maybe the manual advises against use of B and N because drivers might
leave the vehicle in the wrong mode: N when the light turns green,
or B when trying to accelerate quickly.

> As you say, careful pressure on the accelerator (and oddly on the
> brake, too) puts the car into neutral (depending on how anxiously
> the charging system is watching the battery condition -- when the
> charge needs topping, finding the pedal's neutral setting is much
> trickier).

Aha, that explains why accelerator-pedal glide is hard to achieve
when the car is warming up. I have never gotten > 30 mpg during
the first 5 minutes (I'll have to ask my wife if she has) so I bet
a plug-in battery charger would start the car in battery-full mode
and yield better mileage on short trips.

 

[Guest]

In article <[email protected]> [email protected] "Bill Tuthill" writes:

> I've spotted several factual errors in the manual, many probably
> the result of copy 'n' paste from manuals for non-hybrid Toyotas.
> I've also spotted at least 20 grammatical errors, but I read Usenet
> so I'm used to that type of thing. ;-}

That manual is an annoying piece of work all over. As I laboured
through it, I estimated at least a third could have been got rid
of by removing repetition.

> Aha, that explains why accelerator-pedal glide is hard to achieve
> when the car is warming up. I have never gotten > 30 mpg during
> the first 5 minutes (I'll have to ask my wife if she has) so I bet
> a plug-in battery charger would start the car in battery-full mode
> and yield better mileage on short trips.

Keep in mind that mpg improves as the petrol engine warms. That
will be why they go to the trouble of storing engine coolant in
an insulated container between runs. And the engine starts at a
low speed. Even a really "clever" battery charger seems unlikely
to help there unless the trip is laughably short, such as a few
hundred feet, and then you would have to keep the speed down.
--
Andrew Stephenson

 

[Guest]

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.

 

[Guest]

In article <[email protected]> [email protected] "Bill
Tuthill" writes:

> [...] it would be nice to have a setting for "do not use
> gasoline engine until notified otherwise."

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.
--
Andrew Stephenson

 

[Guest]

As is the case with all hybrids one is not likely to save, in fuel costs,
anywhere near the premium it costs to buy the vehicle during the time the
average new vehicle buy keeps their vehicle. Those that keep them longer
than average needs to be concerned about the battery repayment cost. If
your are rich and your intention is to save the world, that's another story.



mike


"Bill Tuthill" <[email protected]> wrote in message
news:[email protected]
> 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.
>

 

[Guest]

Andrew Stephenson <[email protected]> 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.

 

[Guest]

"Bill Tuthill" <[email protected]> wrote in message
news:[email protected]
> Andrew Stephenson <[email protected]> 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 hybrid controller on the Prius keeps the NiMH batteries at between 45%
and 65% charged to maximize battery life. Here is an article about how it
works: http://oregonstate.edu/~tongt/camry/index.html

--

Ray O
(correct punctuation to reply)

 

[Guest]

On 28 Dec 2006 18:11:27 -0800, Bill Tuthill <[email protected]>
wrote:
>Andrew Stephenson <[email protected]> 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 >>--

 

[Guest]

In article <[email protected]> [email protected] "Bill
Tuthill" writes:

> [...] 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 now feel, from later experiments, that the car switched back to
normal mode from EV because of the speed it had reached, rather
than the charge level. However, the points made by Ray and Bruce
would seem valid. Either way, attainable range on EV is not big.
--
Andrew Stephenson

 

[Guest]

Ray O <rokigawaATtristarassociatesDOTcom> wrote:

> The hybrid controller on the Prius keeps the NiMH batteries at between
> 45% and 65% charged to maximize battery life. Here is an article about
> how it works: http://oregonstate.edu/~tongt/camry/index.html

Thanks, but that link has Camry information and nothing I can find
about the Prius or hybrid synergy drive. Can you give another URL?

---
Bruce L. Bergman <[email protected]> wrote:
>
>> I thought NiMH batteries could go near 0% without damage.
>
> 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.

The Prius manual says there is a 12V accessory battery in there somewhere.
Wouldn't it be enough to start the gasoline engine?

My mom lives in upstate NY where it gets very cold, and Toyota replaced
her 12V NiMH accessory battery with lead-acid, which performs better
in cold weather. This helped her Prius start up better on cold mornings
after many days of non-operation.

 

[Guest]

"Bill Tuthill" <[email protected]> wrote in message
news:[email protected]
> Ray O <rokigawaATtristarassociatesDOTcom> wrote:
>
>> The hybrid controller on the Prius keeps the NiMH batteries at between
>> 45% and 65% charged to maximize battery life. Here is an article about
>> how it works: http://oregonstate.edu/~tongt/camry/index.html
>
> Thanks, but that link has Camry information and nothing I can find
> about the Prius or hybrid synergy drive. Can you give another URL?

I found the link I posted by doing a google search. You could try searching
"Prius hybrid synergy drive battery" and see what comes up. For what it's
worth, the Prius and Camry hybrid drive essentially work the same way, and
the state of battery charge will be the same.
--

Ray O
(correct punctuation to reply)


>
> ---
> Bruce L. Bergman <[email protected]> wrote:
>>
>>> I thought NiMH batteries could go near 0% without damage.
>>
>> 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.
>
> The Prius manual says there is a 12V accessory battery in there somewhere.
> Wouldn't it be enough to start the gasoline engine?
>
> My mom lives in upstate NY where it gets very cold, and Toyota replaced
> her 12V NiMH accessory battery with lead-acid, which performs better
> in cold weather. This helped her Prius start up better on cold mornings
> after many days of non-operation.
>