Stupid question about the Prius and hybrids

[geezerman402]

If the electric motor is being charged by the combustion engine, wouldn't conservation of energy say that the electric motor is no help at all? And that the Prius and other hybrids are only good on fuel because of weight/wheel size/engine size?

[kronus]

The electric motor is a lot more efficient at low RPMs, especially when starting from a stop. Electric motors produce peak torque when almost not moving.

The Prius also uses regenerative braking, which converts kinetic energy of the car's motion into stored electrical energy when you stop or slow down. This stored energy is then used at a much higher efficiency than the small gas engine's to get the car going again.

The gas engine is used for cruising and keeping the batteries charged. The Prius tries to 'keep off the throttle' of the gas engine to save fuel.

[daniel]

i think it is charged by some regenerative braking system, not necessarily by the engine running.

http://en.wikipedia.org/wiki/Toyota_Prius#Design_and_technology

[e34john]

I think they only charge when you are on the brakes. They are only good on fuel while in the city, since the electric motor is used to take off. Once your on the highways its almost all gas and has about the same MPG as its gas counterpart.

[jflip2002]

Nissan Versas get more MPG than a Nissan Altima hybrid.

[StereoInstaller1]

I thought the Prius runs on human souls?

[jflip2002]

If by humans, you mean aborted babies, then yes.

[kylebes1]

The Prius uses an atkinson cycle engine... rather interesting. It has better low speed efficiency and blah blah... I did not realize the Prius has no transmission...

[StereoInstaller1]

Just an incinerator, no transmission

[TwoJ's]

Also note that electric motors have efficiency upwards of 95% while gasoline engines are around 40%.

The hybrid car is a great idea, but the technology needs to catch up before it can truly be effective.

[Hodge]

Can't tell you how many Prius's I see speeding on the highways, thinking they are getting exciting gas mileage, but in actuality they are using more gas than they think...

I would never buy one of those, especially since BMW Diesels in Europe get the same or better mileage, and actually have performance.

[Collin]

The Prius uses an atkinson cycle engine... rather interesting. It has better low speed efficiency and blah blah... I did not realize the Prius has no transmission...

All cars have transmissions. If they didn't there would be no transfer of power from the engine to the wheels (unless it's a direct gear which would be crazy for any motor not capable of 35,000 rpms). The Prius has a form of CVT, minus the belts like in Nissans.

The Prius' batteries receive charge from both the brakes and the gas engine, which combined provide enough energy to keep the batteries charged while still driving. Under medium-heavy acceleration the gas engine kicks on, and while cruising or lightly accelerating the electric motor propels the car.

It's an overly complicated system that can easily be matched by small diesel engines in both power and efficiency (MPG and carbon output). Though the 2009 model is supposedly going to make 94 MPG.

According to edmunds.com, US cars ranked by claimed mileage:

1. Honda Insight - 60/66 mpg
2. Toyota Prius 60/51
3. Honda Civic Hybrid — 49/51
4. Volkswagen Golf TDI — 37/44
   Volkswagen New Beetle TDI— 37/44
5. Volkswagen Jetta TDI — 36/41
6. Toyota Corolla — 32/41

[DCColegrove]

Also note that electric motors have efficiency upwards of 95% while gasoline engines are around 40%.

The hybrid car is a great idea, but the technology needs to catch up before it can truly be effective.

Currently battery technology isn't quite there yet...

Way back I was involved in some electric car R&D... We were working on a VW Rabbit Chassis... It weighed in at 5800 LBS...

So... Batteries have come a long way since the 80's but still have a way to go.

[s0urce]

The prius also runs on obama stickers.

[TwoJ's]

Currently battery technology isn't quite there yet...

Yeah, that's what I was getting at. We can regenerate all the energy we want from brakes and shit, but if there is no effective place to store it then it's not worth it.

The technology will come around though, and I will own an electric sports car some day, I'm sure.