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We just got delivery on a 2006 Prius and have a huge 123 miles on it. Its a great car, but I would swear that there are situations on flat gound in which the engine cuts in unnecessarily when the car would function just fine on electric alone. Is the low-end point for engine operation something that the dealer can adjust, or is this just the way Toyota designed it. Also, when I back up on flat gound out of the garage in reverse, it won't do it on electric - the engine comes one (unnessarily, I think).
 

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It could be that the ICE temperature was a little low and the ICE needed to run to warm up. It will do that in cold weather. As for backing out of the garage, the ICE will come on about 15 to 30 seconds (can't remember the exact time) after powering up to warm up and throw a charge on the battery.

From what you have described, I would say everything is normal. Enjoy the car and don't try to analyze it.
 

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There are any number of reasons the ICE may have kicked in. Your flat terrain may actually have been a slight uphill grade and your energy demand from the battery exceeded ~40 amps...the approximate threshold for non-EV button 'stealth' driving.

It may be that the ICE was cool, as suggested.

It may be that you had the defroster on or the heat or A/C on.

It may be that you slightly depressed the accelerator.

It may be that you were going over 42mph where the ICE is already spinning (but not consuming fuel) and the threashold for ICE coming on is lower.

This is stuff that is integral to the efficient functining of the HSD and is not adjustable at the consumer level.
 

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"Also, when I back up on flat gound out of the garage in reverse, it won't do it on electric - the engine comes one (unnessarily, I think)."


Everything efusco said...

Also, the Prius can ONLY use electric going in reverse, since there is no reverse gear on the CVT.

Cheers!
-Ray
 

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The car uses fuzzy logic, so there are times when either all electric, or with ICE could be used. Sometimes I too find that it may use ICE when all electric would be better, judging from the instantaneous MPG display. As you gain experience with the car, you can make your own judgements and encourage the car to go one way or the other, based on what would be more efficient.

Keep in mind though, the car totally runs on gasoline, whether the gasoline is used immediately, or deferred for later consumption. If you go all electric, you have to replace that energy somehow. Usually that would be with ICE, though regen on a long downhill run would appear as free energy (as opposed to friction brakes).

As for reverse, it is true that the wheels are driven completely by the electric motor MG2, however its power can come from ICE through MG1 rather than or in addition to the battery.
 

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DanMan32 said:
As for reverse, it is true that the wheels are driven completely by the electric motor MG2, however its power can come from ICE through MG1 rather than or in addition to the battery.
That's a good clarification. While the actual drive power is solely from an electric motor (in reverse,) the power to RUN that electric motor might come from the gas engine. That's how I read RED's comment the first time, but for a 'newbie', I can see the confusion.

I have a pretty steep driveway that I often back out of (when my wife forgets to back in,) and unless I floor the pedal, I can get up it with no problem using only the battery. (And, it's a gravel driveway, so if I floor it, the traction control tends to kick in, anyway.)

As the original poster is in Bremerton, Washington, I'm leaning toward either cold ICE or defroster on. I know that mornings here in Portland are cold enough to keep the ICE going for 5-10 minutes, regardless of driving habits. And if I have the defrsoter on, the ICE will go for the first 15-20 minutes. (I tend to only use it until the windshield is defogged, then go to 'Auto A/C'. Even then, I turn it off at stop lights until the ICE has warmed up enough to turn off automatically.)
 

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efusco said:
There are any number of reasons the ICE may have kicked in. Your flat terrain may actually have been a slight uphill grade and your energy demand from the battery exceeded ~40 amps...the approximate threshold for non-EV button 'stealth' driving.

It may be that the ICE was cool, as suggested.

It may be that you had the defroster on or the heat or A/C on.

It may be that you slightly depressed the accelerator.

It may be that you were going over 42mph where the ICE is already spinning (but not consuming fuel) and the threashold for ICE coming on is lower.

This is stuff that is integral to the efficient functining of the HSD and is not adjustable at the consumer level.
Adding to Evan's comments...

It may be that the vehicle is in the Stage-3 of warming up process and going to do "idling check".

It may be that the SOC of HV battery is too low.

It may be that the SOC of HV battery is too high.

[email protected]
 

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Unnecessary ICE...

I had the same feeling when I picked up our '06. Especially when on a down slope. Now we're on our 3rd tank, and it seems to run on the battery more. The MPG are up about 7-8 since the first tank of fuel.
 

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Hi Jveatch,

I am in a similar situation to you, except being in Chicagoland and having put about 400 miles on my new Prius since Wednesday morning.

One thing I noticed was the accelerator pedal action. In a standard car, one accellerates pushing the pedal maybe 2/3 s the way down, then back off the pedal to 1/3 to 1/2 to maintain speed.

In the Prius, that cruise point is more like 1/8 to 1/4 pedal depression. That is were the engine might turn off, in cold weather driving, in a warmed up car. Maintaining the pedal depression at 1/2 will keep the engine running. My guess is it was programmed this way to give the operator a way to have the car ready for quick response, say in merging traffic.

The lack of rythmic noise takes getting used to. As a Ham Radio operator, but not blind, but having known blind Ham Radio operators; they have a box which hooks up to the meters on power amplifiers. The box emits a pitch depending on the meter position, and this aids them in tuning up the amplifier for the frequency they will be transmitting on.

Subconciously in a standard car, the engine-rythmic-noise provides that feed back as, even with an automatic transmission, the car speed is relatively proportional to the engine speed , at least at cruise. In the Prius, the engine speed is not closely related to vehicle speed, and the engine is hard to hear over the road noise, or may even be off!. I figured out the pedal thing by looking quickly back and forth at the speedometer, the MFD and the road. It would be nice to have an tonal aural, or vibrator (steering wheel or seat?) feedback for vehicle speed, or MFD funcional displays however. The MFD Hybrid functional displays appear to me to be about 1/2 second behind what the car is actually doing. So, one needs to maintain an action for at least 1/2 second and then get the MFD feedback.

On the drive home yesterday, I obtained the first warp-cruise (All electric at 40 mph - if I have the terminology right?) operation out of the car.
 

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I used to use aural queues to determine vehicle speed (or at least change in speed) myself. My first car was LOUD, especially when I had some exhaust issues. When I would get my next car, it was quieter, so it took some time to be able to hear the queue of the engine rev.

Tire noise may be what we need to queue on, since there's not much else.
 
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