Is EV button/mode a novelty??

I only use it as a feel good factor- at the end of my homeward commute, I can slowly roll down hill and get a tiny boost in mpg if I remember to do so- also, if you drive thru a lot of parking lots to find a good parking spot, its useful.

 

Great question. I just let the car computer decide.

 

I definitely CAN turn EV mode on after about 10 minutes of driving in the morning - I do it every day when I drop my daughter at school, first thing in the morning. The limitation is that you must go slowly enough, and not up the hill. I get up to 28 mph on EV, if I go without accelerating fast.

 

There are limited circumstances you can take advantage of the EV. For me, it was turning into my neighborhood and concluding that final drive using only electricity and with extra power the button provides. In the ramp at work, it came in quite handy too. For both situations, the engine was always fully warmed.

Now driving the PHV, it's nice knowing the regular models have the button. That makes explaining how the same system can provide quite a bit more power & speed simply by having more battery available easier. You get a small taste of the difference without having a plug.

 

I use it all the time when I need to move between parking spaces.

 

Get an aftermarket device, so you can see coolant temperature. Otherwise, you'll continue to guess. The mode is only available when the engine is fully warmed.

 

Cold engine, EV = 10 mph max

Warm engine, EV = 25 mph max

Warm engine, STEALTH = 46 mph max

Both EV and STEALTH are electric-only driving modes. EV offers more power, but has a lower maximum speed. It must also be manually requested. STEALTH is automatic, but with a faster maximum.

 

I find this more power to be extremely limited. It doesn't take pushing the accelerator much past the middle of the HSI for the car decide to deactivate the requested EV mode for excessive acceleration.

 

The only time I ever use the EV button is to prevent the ICE from starting when moving the car a short distance, ie. driveway to garage. The rest of the time I just feather the pedal to get in to and out of EV mode up to 46 mph once the car is warm.

 

Just remember, too, that if you use EV mode, the power for its recharge has to come back from somewhere (that is, the ICE). So unless you're moving it in a parking space or your driveway as others have mentioned, you won't really be positively affecting your mpg numbers.

 

No vital utility here. Yeah, changing parking spaces, if one enjoys the idea of doing this without turning on the engine (nifty but not essential). If you disconnect the "growler" speaker, maybe Eco mode is useful for sneaking up to and/or away from a location in silence (useful for criminal activity or escaping awkward social encounters). Impress your friends with a short hop on an underpowered electric vehicle.

As has been noted, the "Eco" label is misleading, because there's nothing ecological about this mode. The energy all comes from the gas engine; Eco mode just says to get it later rather than now. It's the distinction between earning a paycheck and spending money from your savings or borrowing.

 

That misconception seems to be spreading.

ECO mode changes the tolerances for both the Heater and A/C, which most definitely has an effect on efficiency.

 

It also remaps the throttle at lower pedal positions...

 

The button is a novelty that is near useless. The EV mode itself is not, however- it is a critical part of pulse and glide (shutting off the engine, but not using EV power) that can lead to enormous mpg below 43-45 mph.

 

We seem to be confusing eco and EV mode. Eco mode changes climate control settings and gas pedal response. EV mode is driving with the ICE off. EV mode is not always bad. Why do we have to argue extremes? First someone says to use EV mode as much as possible, and then someone replies and says that EV mode is the work of the devil.

If you only need a little acceleration, EV is more efficient than running the ICE, unless your battery is in serious need of charge (because it's low, you're about to climb a hill, etc.). This depends on where you're going to drive next, temperature, climate control, etc., but there are definitely times when EV use is appropriate. In other words, there are times when the ICE-battery conversion losses are less than the loss in efficiency when running the ICE at a low acceleration/lower efficiency state.

 

We're also confusing putting the car into EV mode without using any or using only very little battery power (gliding) and using much EV power to accelerate or maintain speed of the car.

Basically, below 43-45 mph you should be attempting to pulse and glide as much as possible (Google it or search here on the forums- not you, minkus ). Pulse and glide is especially useful on a slight decline (it is very difficult, and perhaps not a good idea, to do when going uphill). However, this is not the same thing as putting the car into EV mode and then cranking up the EV power to push it along, which, in most situations, will be an inefficient use of power. There would have to either already be a surplus of energy in the battery (from braking or otherwise) or an upcoming opportunity to replenish the battery using the brakes for it to be an efficient use of EV mode.

The beauty of the Prius is being able to shut the engine off. The traction battery adding power also helps mpg in many ways, but the "big-time" mpg comes from the fact that, at in-town speeds, you can gain distance in the car without the engine running (AND without using much or any EV power), you can shut off the engine at stoplights, use the traction battery only at very low speeds in parking lots, etc.