Quote:
Originally Posted by CurtEgerer
But where are you finding a 56MPG average with a Prius? The magazine tests all seem to report real world mileage in the high 30's / low 40's. Obviously, the mileage will be fantastic if you do mainly city driving on electric, otherwise it's just another small gasoline powered car ruining the environment  |
Real world is around high-40s in city, driving "normally". Even my leadfoot wife usually gets around that. On freeway, 50s is normal. On a suburban or freeway commute, I might get 56, but not on the all-city and somewhat hilly route that Madam Leadfoot drives. To get high-30s, you usually need quite adverse circumstances (short trips with cold engine in cold weather, or lots of hills). To get 60s and higher, as some do, you need an near-optimal route and a very economical driving style.
"Mainly city driving on electric" is not possible. The traction battery is small and gives only a couple miles range, then the gas motor kicks in. Plus the gas motor kicks in if you do more than lightly press the throttle pedal or if you exceed 25 or 30 mph (don't recall exactly).
Go back in the thread a bit, I think I posted a description of how the Prius works. Basically, think of it as a very aerodynamic car with low-rolling resistance tires, powered by a gas engine much smaller than a car of its size and class would usually have. Then imagine that you shut the gas motor off every time you take your foot off the throttle pedal (stoplights, coasting, etc) rather than letting it idle. That is basically 90% of how the Prius gets its MPG. For the last 10%, imagine that for short distances at low speed you can switch on an electric motor. Oh, and the drivetrain uses a sort of continuously variable transmission.
Toyota is working on a next-gen Prius that will have a larger traction battery, probably using lithium-ion, which can be plugged in to recharge overnight or when parked at work. That will allow you to make modest trips (maybe 20 miles) on battery power, with the gas engine kicking in for more acceleration or when the battery is mostly drained. Recharging from a wall socket will of course consume energy, in the US much of that will be coal-generated, so not free and not non-polluting, but not from Middle East oil anyway. There are prototypes running around Japan and the US. But I think it will be a couple more years before this is in production. My guess is that one concern is the safety of such a large lithium ion battery. Look at all the recent recalls of cellphone and laptop lithium ion batteries. Another issue may be the longevity of a battery that is put through a full discharge cycle daily. The current Prius keeps its battery state of charge within a narrow range, which is why the battery can be warranteed for such a long period.
It is a very interesting car with a lot of technology. Not for everyone, but we like it a lot.