Y'all need to drive a hybrid for a week or two.
The ICE is an internal combustion engine. It drives a generator (or alternator, with an accompanying inverter). This produces electricity which goes into the battery and/or powers the electric motor that drives the wheels. Every time energy is converted in form, there are losses. Thus, at least on the face of it, this little car with its multi-conversion drivetrain stands to be less efficient, when it is burning gasoline, than if that little ICE were hooked directly to the wheels. Now, there are some other mitigating factors (the ability to operate the ICE at a constant efficient speed, regenerative braking, etc), but there are also some exacerbating ones (hauling around hundreds of pounds of dead-weight discharged batteries).
Sam, those are good points. No matter how efficient the electric motor you are getting a cut in efficiency due to both the ICE and electric motor running. However, besides ERD50's points, you also have the fact that the car is still using the battery as well as the ICE.
I don't know what the performance hit will be, but I am not willing to assume that it will be miserable until I test drive it, or I hear a lot of reports from customers. Likewise, I am not willing to assume it will be a negligable hit to performance.
Yep, conversion losses suck. A plug-in car seems more "efficient" (more MPG) on battery because vehicle manufacturers don't have to care how the electricity got to the plug. As far as they're required to show, the electricity goes straight from the battery to the motor-generator to the transmission and to the wheels. The real "performance" difference is that the electricity is cheaper than gasoline, not more efficient. No car manufacturer wants to have to list how much atmospheric carbon was generated to produce the electricity that's at the plug. Or maybe a utility plant is more efficient than an ICE. I don't know.
The fact is that a hybrid without a plug is less efficient on battery because it has to burn its own gas, make electricity, store it in the battery, and then suck it back out of the battery to spin the wheels. That doesn't save gas. The vast majority of the hybrid's gas savings come from not having to idle the ICE all the time.
In fact a number of American Prius owners (me among them) are pissed off that when the engine is cold, the car's ICE runs for 45 seconds after startup. There's absolutely no engineering reason for this-- it's to warm up the engine (and catalytic converter) to qualify for the the EPA rating as "practically zero emissions". Non-American Priuses have dashboard buttons (as does the American 2010 model) to circumvent this bureaucratic nonsense, and some American Prius geeks (not me) wire in their own buttons.
Toyota actually tries to keep the engine hot when the car is parked. After a Prius is turned off, a small pump puts the hot radiator coolant into a thermos storage bottle, which can avoid the engine warmup upon startup after a short parking period. Some Prius owners in warm climates (again not me) actually install engine block heaters and turn them on 20 minutes before they start the car-- it satisifies the car's microprocessor controller that the catalytic converter is hot, so it avoids the 45-second warmup. But again the electricity to the engine block heater costs less than the gas. It's not necessarily more efficient.
IIRC Volkswagen used to make a high-MPG diesel car engine that shut down when the car was coasting. (It apparently freaked out drivers who worried about accelerator-pedal lag.) That VW would always use less gas than a Prius hauling hundreds of pounds of batteries.
When this 3400 lb car heads up a 20 mile long uphill grade with its discharged battery pack and a whopping 100HP, something's gotta give.
Whereas it was a sprightly performer when fully charged around town, now it is an entirely different vehicle. The pretty displays and soft warning voices are not gonna be enough to keep drivers safe when they hang their little pink bodies out into traffic and try to pass.
The car's always hauling around a battery pack with its whopping 100 HP. There's nothing to give in the first place. It's no more a "sprightly performer" when fully charged than when almost discharged. There's no acceleration performance difference between fully charged and fully discharged, any more than a conventional car's acceleration performance changes when the gas tank is nearly full or nearly empty. The Prius looks cute in the ads, but in terms of weight & volume it's more the size of a Ford Taurus station wagon than a sedan.
There's no noticeable difference in Prius acceleration between motor generator and ICE. That MG provides plenty of torque. Certainly
(ahem) more than enough to peel rubber and more than the average teen driver expects (or can handle). The nice thing about the car's propulsion train is that you can just stomp on the pedal without having to coordinate shifting gears or waiting through automatic transmission downshifts. A CVT is way better than any transmission I've ever driven before.
Another nice difference about a Prius is that when you accelerate from a stop, you punch it. You actually do a jackrabbit start. It's more efficient (more MPG!) than slowly accelerating on battery. The reason is that the car's microprocessor controller immediately spins up the ICE with the MG and
then gases the ICE. The ICE wasn't wasting gas at idle, and it begins operating at its most efficient speed without any inefficient burning of gas to get up to that speed. The car immediately begins operating on its most efficient means of propulsion, and fewer battery amps are wasted to get the car up to speed before starting up the engine. Feels kinda strange to teach your kid to drive by saying "Punch it!"
Jackrabbit starts would be bad on plug-ins. The plug-in goal would be to never run the ICE because its fuel costs more than the battery's receptacle plug.
I think a week or two behind a hybrid wheel would be worth a thousand words. If you feel that you need plenty of reserve to be able to pass uphill or accelerate into traffic... well... you either need to drive a car [-]that makes you feel safer[/-] with a higher thrust-to-weight ratio or you need to change your driving habits. Our teen always has far more acceleration than she needs for whatever she thinks she's doing. Me, I just try to avoid accelerating. I'm no hypermiler but a Prius dashboard display gives plenty of information to make a driver less wasteful of fuel, whether it's gasoline or electrons.
Now let's talk about "efficiency" when a plug-in hybrid is charged from a photovoltaic array!
