New Owner Here

[darelldd]

<div class='quotetop'>QUOTE(Lil Mo @ Jun 30 2006, 06:07 PM) [snapback]279425[/snapback]</div>

A number of things on the Nav system get locked out.

Sometimes it really gets my goat!

On the other hand, it probably keeps me safe.

For several days after getting my 2006 Prius, I thought the Bluetooth phone had a problem because I could not consistently get to the functions. The I realized, they were greyed out during motion. Doh!!!
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Of course you can fix this grey-out problem quite easily! Just tell the car you aren't rolling. Presto. Everything works as if you are stopped.

http://www.darelldd.com/ev/prius_speed_wire.htm

[j24816]

<div class='quotetop'>QUOTE(Sarge @ Jun 26 2006, 11:05 AM) [snapback]276901[/snapback]</div>

My understanding is that the leaf car represents 50Wh that is regenerated, whether by regen braking or by coasting (simulated engine braking by running generator).
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I thought the cars only appeared if you were braking, and thus are not desirable, and provide useful feedback on driving technique.

If they are displayed when coasting then they are merely interesting.

Can anyone definatively answer?

[qbee42]

<div class='quotetop'>QUOTE(Sarge @ Jun 26 2006, 02:05 PM) [snapback]276901[/snapback]</div>

Hmmm... I disagree with both theories.

My understanding is that the leaf car represents 50Wh that is regenerated, whether by regen braking or by coasting (simulated engine braking by running generator).
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Simulated engine braking by running generator is regen braking. It works exactly the same way as when you press the brake pedal.

I don't think it is accurate to say a blanked statement about leaf cars being good or bad, as it would depend on the driving situation. It merely indicates that energy that would have been lost in a conventional car was preserved in this car.

Consider, if you are in bumper to bumper and constantly doing gas/brake/gas/brake, then you will see the cars appear for the braking, but this is less efficient driving than coasting at a moderate speed which will use less energy for both accelerating and decelerating (and in turn generate fewer leaf cars). So these leaf cars are bad with respect to efficient driving.

On the other hand, if you are rolling downhill applying no throttle, the 'engine braking' will run and generate 'free' power to be used later, of course assuming the SOC is not already full. So these leaf cars are good for efficient driving.
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Leaf cars are always bad. They are only good in the sense that they are better than throwing away the braking energy as is done with a conventional car. There are significant losses in the regen-battery-motor cycle. From an energy standpoint, it is always better to coast than regen. In your example of rolling downhill, it would be better from an energy standpoint to apply just enough throttle to turn off the 'engine braking' simulation and coast down the hill. This way all of the 'free' energy is stored in the car as kinetic energy without all of the losses associated with regen, batteries, and motors. In the case of coasting, there is a small extra loss associated with the increase of speed, but that is small compared to regen losses.

Obviously, you can't always coast, and some driving situations require a lot of braking, so you are going to get leaf cars on the display. Don't worry about it, but keep in mind that they are not desirable, just better than driving a regular car.

Tom

[Lil Mo]

<div class='quotetop'>QUOTE(darelldd @ Jun 30 2006, 07:17 PM) [snapback]279460[/snapback]</div>

Of course you can fix this grey-out problem quite easily! Just tell the car you aren't rolling. Presto. Everything works as if you are stopped.

http://www.darelldd.com/ev/prius_speed_wire.htm
[/b]

Cool. It may be some time before I am brave enough to start these kinds of mods, but it is great to know that it can be done.

Thanks,

[Sarge]

<div class='quotetop'>QUOTE(qbee42 @ Jul 2 2006, 08:45 AM) [snapback]280053[/snapback]</div>

Leaf cars are always bad. They are only good in the sense that they are better than throwing away the braking energy as is done with a conventional car. There are significant losses in the regen-battery-motor cycle. From an energy standpoint, it is always better to coast than regen. In your example of rolling downhill, it would be better from an energy standpoint to apply just enough throttle to turn off the 'engine braking' simulation and coast down the hill. This way all of the 'free' energy is stored in the car as kinetic energy without all of the losses associated with regen, batteries, and motors. In the case of coasting, there is a small extra loss associated with the increase of speed, but that is small compared to regen losses.

Obviously, you can't always coast, and some driving situations require a lot of braking, so you are going to get leaf cars on the display. Don't worry about it, but keep in mind that they are not desirable, just better than driving a regular car.
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Hi Tom, your explanation makes sense, and I am not doubting that you are right.

The theory behind my logic is more drawn from your last statement - compared to a regular car. I am sure that compared to true coasting with no arrows, regen is inefficient. But compared to a conventional car rolling downhill and either braking or engine braking (both = 100% energy loss), the Prius is able to recapture that energy, symbolized by the leaf cars. Which is good. My example of rolling downhill was probably not a good one as I left out key details such as rate of decline, which can have an effect on whether coasting vs engine braking is practical. If slowing down is necessary anyway, then we may as well collect leaf cars in the process, right?

So perhaps I just didn't explain my reasoning and examples completely...

Thanks for the feedback though... always happy to learn something!

- Kevin