When does the electro motor kick in?

[zijlstra]

I've had my Prius for about 4 weeks now and I've noticed that it virtually NEVER drives with the electric motor alone. The regular gas engine is almost always on, especially when I stop at a stoplight and start driving again. Unless I go ULTRA slow (like walking-speed), the gas engine immediately kicks in. Is this normal? When we bought it the sales-guy kept pointing out that the Prius can go up to 35 mph on electric alone, so how come it NEVER does this, but is always running in combination with the gas engine??

[efusco]

Yea, it's a bit frustrating that the salesmen use that "electric only up to...." stuff to sell the car.

The car IS capable of speeds up to 41mph on electric only, but it's essentially impossible to get it to that speed from a stop unless you're on a pretty good downhill grade. the reason is b/c it is less fuel efficient to drive on the battery power alone than it is to drive with the ICE...particularly when accelerating from a stop. The ICE will kick off when you slow down at speeds below 41mph and you'll use the battery only in very slow moving situations such as traffic jams.

Your car is working normally and being it's most fuel efficient in doing so.

[Sufferin' Prius Envy]

<div class='quotetop'>QUOTE(alaskaprius @ Apr 22 2007, 04:14 PM) [snapback]427973[/snapback]</div>

I've had my Prius for about 4 weeks now and I've noticed that it virtually NEVER drives with the electric motor alone. The regular gas engine is almost always on, especially when I stop at a stoplight and start driving again. Unless I go ULTRA slow (like walking-speed), the gas engine immediately kicks in. Is this normal? When we bought it the sales-guy kept pointing out that the Prius can go up to 35 mph on electric alone, so how come it NEVER does this, but is always running in combination with the gas engine??[/b]

First of all . . . Anchorage . . . burrrrrrrrrr. [Just reliving a couple of very cold December days I spent in Anchorage ]

That could be problem #1. Cold weather.

Cold weather and high MPG don't go hand in hand with a Prius.

If you have the heater on and/or are driving short distances, the gas engine will run longer than if the car were in warm weather and no heating or air conditioning running.

If you only drive short distances, the Prius doesn't have an opportunity to finish it's warm-up cycle . . . the gas engine will continue to run, even when the car is at a standstill.

Sometimes you can force the gas engine off early if you shift into neutral and then back to drive. This often can be accomplished after just a few blocks of driving, but chances are much better with the heater off.

Try accelerating slowly.

The sales creature got it wrong. It can get up to approximately 41 MPH on only battery power.

[efusco]

Sufferin's right on the cold thing and it's an important point. The ICE will run quite a lot in cold weather just to keep itself and the Catalytic converter warm. Also, the battery works less efficiently when it's cold, so if you park outside it'll be pretty cold and less able to provide the power it could if warm.

There are several threads here that discuss engine block heaters (are they standard in Alaska?) and blocking the grills on the Prius...both of these will go a long way to pre-warm and keep warm the ICE and reduce it's superfluous running time.

[donee]

Hi Alaska...

Accellerating on All Electric is really a mileage no-no. And the car is programmed to not use electric acceleration, except at very very slow acceleration.

Once up to a speed between 25 and 41 mph, with the state of charge (SOC) up above half, and the car well warmed (its also easier if the battery is warm - use solar gain to keep the inside of the car warm when possible in the winter) an experienced Prius driver can drop the car into electric readily.

Its good to accellerate a little faster than than other cars on the road, but just a little. Then, when up to speed lift off the throttle completely, see the green arrows, then slowly increase the throttle till the yellow arrows light. If your in a slighly downhill situation, and warm temps (low tire drag), you may be able to maintain speed without bringing the yellow arrows on (this is called "glide"). In that case, just push down the throttle till the green arrows go out but not farther. In steep downhills, you may maintain speed with the green arrows on.

[zijlstra]

Thanks for all the replies! Good to know that my Prius is functioning 'normally'.

BTW, it is not as cold up here as many of you might think. I'm pretty sure that many states in the MidWest get temperature just as cold (or colder) as Anchorage, which has relatively 'mild' winters for Alaska. Right now we're in the upper 40s to mid 50s range, so the heater in the Prius isn't even on any longer, unless it gets real chilly over night.

[darelldd]

<div class='quotetop'>QUOTE(alaskaprius @ Apr 23 2007, 09:55 PM) [snapback]428864[/snapback]</div>

Thanks for all the replies! Good to know that my Prius is functioning 'normally'. [/b]

And too bad that the sales guys can't get a handle on it!

As others have said, it is more efficient for the Prius to use the ICE primarily, and blend in the e-motor when acceleration is needed. The guys who get the best mileage use the battery as little as possible. The traction battery and motor are there for a reason - but that reason is NOT to make the car an EV - it is to make the ICE a bit more efficient at certain times of high demand. You are driving a gasoline car, with a bit of electric assist.

But hey - I have the opposite problem in my Rav4EV. I can't get the gasoline engine to ever turn ON! (Here comes the 2x4).

[Charles Suitt]

Perhaps you remember "HAL" the computer on the space mission movie of some years back.

Think this way... HAL (Prius computers) decides when and how much ICE (Internal Combustion Engine) and Electric Motor power to use at a given time depending on all factors, especially your power requests. So, you are relieved of the responsibility of controlling how much of which power source to apply... or even the ability to exert your influence. Some Prius owners have installed the "EV" (Electric Vehicle) button modification which allows the driver to prevent the ICE from being engaged, so those drivers can override HAL for limited periods.

Previous posts are correct, ambient temperatures will most certainly cause the ICE to run more and the block heater modification would be beneficial in your area.