EV Mode: How Far Do You Get?

I'd say you did just fine in EV mode. I can only get about a half mile and then I have to stay below about 10 MPH. EV is really not intended for driving on the open road, more just moving around a parking lot or such.

 

That's the Plug In Prius

 

It would need a MUCH bigger battery - hybrid design could incorporate that, but at a cost. Essentially you want to buy a PIP (which isn't available now) and use it as a hybrid.

Anything is a compromise - power, speed, battery range, fuel tank size, and TOYOTA has chosen the current Gen 4 specifications as a good balance. EV mode alone isn't a big factor in the overall fuel economy stakes, its more in the regeneration of energy when there is a surplus, temporary storage of that power, and usage of that power in conjunction with the ICE as the complex computer algorithms think best.

With your 199.9 MPG - I wonder if that is the maximum that it will display? The more real average would be to continue to drive till the battery is again full - which the computer may baulk at and drop into EV mode from time to time making it a frustrating exercise.

 

estimate for Prius Prime is 22 miles

 

To the original OP - to clarify: an hybrid vehicle is not meant to be driven in EV mode. It is a misconception driven from the desire to drive an EV - it is not.

Any hybrid car, that doesn't have a range extender, is a gasoline powered engine, that improves on the deficiencies of gasoline engines and required gear shifting typical of regular cars.

Typically a gas engine has little torque at low rpms. So a gear shifting is required to make it work more efficiently at higher rpms at lower speeds.
An electric engine instead has full torque already at 0 rpm.
So the combined work of the 2 provides a more constant availability of torque at all gasoline engine rpms, hence pushing the car more efficiently, thus increasing mpgs.

That said, as also the user's manual says, driving on purpose on EV mode, affects negatively fuel consumption. And rightly so: the current necessary for the EV driving comes from several conversions of types of energies from gasoline burning, to storage in the battery, and back to the electric engine to move the car. EV mode is to be used sparsely when moving the car for extemely short distances, e.g. in a parking lot, and it has to be seen as a positive "side effect" of having a battery and an electric motor to push the car around, when the gasoline engine is really not necessary (e.g.to prevent a warm up cycle or a portion of it, when moving the car out of the drive way).
EV, as in "sailing at speeds higher than 20 mph", is something different than driving in "EV mode" (EV button pushed).
EV sailing is avoiding using any fuel inefficiently to glide the car at constant speed (or slightly slowing down) by using the electric engine to just give that little torque to keep the car moving (essentially to counteract friction and change of road level - you need very little energy to keep the car moving up to a certain speeds (e.g. city driving) - beyond that you need a lot more energy to counteract aerodynamic friction).

The battery is not there to allow EV driving. The battery is there to act as a buffer to store a portion of the energy that would be otherwise wasted in heat, either from braking or the engine running at an efficient rpm to reduce pollution and deliver torque most efficiently, but this torque might not be required completely at the wheels. You can clearly see that when driving, and the gasoline engine is on, that there is an arrow going to the battery, even if there is no arrow going from the electric engine to the wheels. That is when the gas engine is pushing directly the car because the speed matches well with the current rpm, but the torque generated is high enough to be captured also as current in the battery to be used in the future, when the gas engine cannot be used efficiently.

The battery is also there to provide current to the electric engine, to support (i.e. reduce load) on the gas engine to avoid it running less efficiently.

That all being said, the Prius is mainly a very efficient gasoline engine car, that wastes as little as possible in heat, and compensates the inherent deficiencies of torque delivery of gasoline engines, by helping out with an electric one.
Last but not least, the Prius gasoline engine does not use an Otto cycle, rather a more efficient but less power dense Atkison cycle engine, compensated by an electric engine to provide a driving experience like with a regular engine with gears.

 

pip goes between about 6 and 16 miles on ev, (epa rated at 11 miles) depending on grade, acceleration and speed, with a battery that fills the whole under space of the hatch, which is where the spare and a huge storage area are on the gen 3 lift back.

 

it makes complete sense. the ev button is really only to keep the engine from firing up when you want to move the car a short distance. i use it to back my wf's hycam out of the garage and back.

the volt goes 50 miles on ev with a back up engine, and the bmw i3 with range extending engine goes about 80 miles on ev. neither sell in quantities that make toyota want to build one.

 

To get into EV mode with a cold engine, you need to press the EV mode button as soon as the car is turned on, *before* the engine starts. It is also mentioned in the user's manual if I remember correctly...

 

i think you're right, but in my wf's hycam, if it's too cold, you can't prevent the engine from starting for some reason. not sure what the temp threshold is. i was really hoping gen 4 would allow low speed ev with a cold engine for a limited time based on battery level.

 

I can do it on the Gen3 down to 3 bars.

 

nice! i wonder if that's true here? gets pretty cold there, right?

 

Yes, down to -15C sometimes, ever more rarely, in winter.
You can do it, if you press the Start button, and immediately after the beep you press the EV Mode button. One has to be quick, the lower the temperature.
With Gen4, let's see how sensitive it is.

 

A higher engine temperature is required for EV mode in the USA than elsewhere. That's why your observations don't match Pakitt's.

 

thank you for confirming my suspicions.

 

Why? On what basis should the ICE (gas engine) temp be higher (compared to what standard? regulation? EU law? etc) when not using it if driving in EV mode?