If I'm cruising in EV mode around town and the ICE comes on to charge the batteries my instantaneous MPG drops below 10MPG as long as I try to maintain my 25 miles per hour speed on level terrain.

Is the ICE really that inefficient?

It is inefficient when recharging a low battery. See my article On Hypermiling The Ford Escape Hybrid for details. http://www.cleanmpg.com/

GaryG

The Prius gasoline motor is actually pretty efficient for a spark ignition 4 stroke.The usual claim for a good spark motor is 30% efficiency changing chemical energy(burning) into mechanical energy(crank energy).
A well designed Diesel is supposed to be 40% efficient.
A electric motor will be very efficient-waaay over 85% is my crude guess-changing electrical (it is really chemical) energy into mechanical.
Our ICE is very good for an spark ice ICE.Luck,Charlie

its questions like these where I say, "that's why i try to leave it off as much as possible "

i got around 20 km a liter when i drove a civic 5 spd using advanced hypermiler techniques
and now I drive a salvage nwh20 prius that gets almost to 25 km/l with 195,000 km to date.

It's very efficient. More like 37% ( close to a Diesel due to the Atkinson cycle ).

Your MPG will always be low when your speed is slow.
After all, you get 0 MPG at 0 miles per hour, 1 MPG at 1 MPH, etc.....

But your example shows, it's not always best to run in EV and run the battery down, if you have a lot more driving to do.
Charging puts about 33% more load on the car.
It's a pretty heavy demand on a 2.3L engine.
That's why it is better to recharge with regenerative brakes, when possible.

Don -
Another way of of looking at what you are calling the inefficiency of the ICE is related to having it to do two things at once. Power the wheels and the generator to charge the battery (since your battery is low at start-up). Not really a compromise but a great engineering accomplishment. After the battery starts to fill, the load on the ICE will be less to the generator and more power directed to the wheels.

From AutoBlog (and Fords Manual)

In positive split mode, the gasoline engine is on and works in concert with the traction and generator motors to power the vehicle at moderate speeds or loads. In this mode, the generator is producing energy from the gasoline engine’s output. This energy can be used to charge the batteries or power the traction motor. The traction motor also contributes to the Escape’s motivation.


As far as for a 2.3L 133HP/124LB Torque ICE I think it does a pretty good job. Have used it both on long trips and in-town conditions. The combo of ICE and the added power of the Traction Motor, when you need or want to make a fast acceleration or when up at speed, the combo really pays off. Power when you need it with the balance of great MPG.

You ever pedal a bicycle?

You ever pedal a bicycle with a generator and a light on it?

With the generator on, it's a lot harder to pedal, and you have to work harder to go the same distance. Same thing is happening with the engine. It's both working to recharge the battery and move you forward. When the battery is charged, you'll find that at 35 miles per hour, on level ground, you can get MAX FE on your display. It's just a matter of what that combustion gets you.

And, as the others have said, yes is is efficient.

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