[imflyn]

If the volt is predicted to get 50 mpg when operating in it's range extender mode, why don't we have more vehicles made like that without the battery aspect? Locomotives have been doing it for a long time. This is OLD technology, but was never implemented into cars. Why don't we have cars that are purely electric drive with an ice/gen combo to power the whole thing. Weight and cost would be reduced with no battery to muck around with. I wondered about this several years ago. Most hybrids use the engine as part of the drivetrain and a motor to suplement it, correct?

 

[Texas]

Great question! The answer: If you had the Volt's ICE in your car without the help from the battery the performance would be horrible. People don't realize it but you only need about 20 hp to keep an aerodynamic car moving at a good speed on the highway. You need the burst of energy from the battery (much higher than 55 kW) to give you the good performance. They didn't do it before because battery technology was too expensive.

I have a little secret for you. Don't repeat it too loudly because the other posters will run me out of town. Using the Volt's ICE and hooking it up to a standard transmission to the Volt's wheels would give you better mileage on the highway then going from the ICE to the gen-set to the electric motor (assuming no battery - weigh of both cars are identical). Other posters will yell and scream but it's true! "How can you say that Texas, have you gone crazy?" No. It's just that the efficiency losses are greater for the ICE - Generator - electric motor - drive linkages - wheels than ICE - standard transmission - drive linkages - wheels. Crazy stuff. Huh? I didn’t even bring up the fact that the generator and motor are heavier than the standard transmission. Ouch!

 

[pdt]

Orion buses

There are buses (Orion) that use this setup, but they need a battery just like a normal hybrid (e.g. Prius) needs a battery to handle regenerative braking to recover braking energy and to handle acceleration. I think this setup works well for buses because you don't need a massive transmission and you also get the great torque of electric motors. I believe that is why this setup is used on trains too.

In my opinion, the reason one would not use this setup for a car is that you would need a very large electric motor to move the car, as well as a large generator. In a normal HEV design (Prius) you can use smaller electric motors and a smaller ICE. You do not need the massive torque and thus the transmission requirements are not as heavy duty.

When I asked a GM Volt engineer at Volt Nation what they think the advantage of the E-REV design is, she said it was to maximize use of grid power.

My current thoughts on this are that if you are going to have a plug-in with a long range on battery power, the E-REV design is best. If ther is no plug-in ability or a very small range on battery power the Prius-type setup makes the most sense. GM is doing both with the E-Flex and the 2-mode designs.

 

[imflyn]

I would have figured a couple good capacitors could handle the requirements of acceleration, stop and go, etc. The engine powering the generator could be tuned to be quite effecient seems how it would have a narrow RPM band. Oh well. This is why I didn't go into engineering. I make my own brain hurt with all the questions.
I guess the real reason all the hybrids and stuff are now coming to market is oil prices. It was so cheap for so long, low cost engines were cheaper than expensive hybrids that would never make up for the extra purchase price... until now with $100/barrel oil.

 

[WOW_FCTR]

Great question! The answer: If you had the Volt's ICE in your car without the help from the battery the performance would be horrible. People don't realize it but you only need about 20 hp to keep an aerodynamic car moving at a good speed on the highway. You need the burst of energy from the battery (much higher than 55 kW) to give you the good performance. They didn't do it before because battery technology was too expensive.

I have a little secret for you. Don't repeat it too loudly because the other posters will run me out of town. Using the Volt's ICE and hooking it up to a standard transmission to the Volt's wheels would give you better mileage on the highway then going from the ICE to the gen-set to the electric motor (assuming no battery - weigh of both cars are identical). Other posters will yell and scream but it's true! "How can you say that Texas, have you gone crazy?" No. It's just that the efficiency losses are greater for the ICE - Generator - electric motor - drive linkages - wheels than ICE - standard transmission - drive linkages - wheels. Crazy stuff. Huh? I didn’t even bring up the fact that the generator and motor are heavier than the standard transmission. Ouch!

So this means that GM could build a 50+mpg ICE car today and they aren't?

I was taking a look at the Volt because I liked the concept styling (which I've read here, I might be disappointed in the actual styling?) and because it looked like I could get 50 mpg. The way I would use the car, I would rather not plug it in at all (I know why am I here then ) Hey it was going to be the Camaro or this

I've learned a lot from reading the posts here. And imflyn's question was one of my biggest questions....just wish the answer was different....

I'll have to keep checking in here just to see how it's going....

 

[Steve Brown]

If the volt is predicted to get 50 mpg when operating in it's range extender mode, why don't we have more vehicles made like that without the battery aspect? Locomotives have been doing it for a long time. This is OLD technology, but was never implemented into cars. Why don't we have cars that are purely electric drive with an ice/gen combo to power the whole thing. Weight and cost would be reduced with no battery to muck around with. I wondered about this several years ago. Most hybrids use the engine as part of the drivetrain and a motor to suplement it, correct?

A battery is required anyway to start the internal combustion engine, so it could have additional capacity to supply power for a burst of acceleration, but still be much smaller and lighter than the battery in the standard version of the Volt. The reduced weight would improve efficiency, and because the battery is smaller, the car should cost less. This may not work out too well in mountainous areas, where the battery would be drained long before the car reaches the summit, so it would just chug slowly up the mountain, but it would work great in the plains states. Maybe Chevy could name it the Voltette or the Voltaire.

 

[MrBogey]

I was taking a look at the Volt because I liked the concept styling (which I've read here, I might be disappointed in the actual styling?) and because it looked like I could get 50 mpg. The way I would use the car, I would rather not plug it in at all (I know why am I here then )

That's the whole point of the Volt. the first 40 miles or so of a trip cost a couple of dimes while each 50 miles after cost a few dollars.

 

[Tom]

The other part of the secret is poor performance

"I have a little secret for you. Don't repeat it too loudly because the other posters will run me out of town. Using the Volt's ICE and hooking it up to a standard transmission to the Volt's wheels would give you better mileage on the highway then going from the ICE to the gen-set to the electric motor (assuming no battery - weigh of both cars are identical)."

Yes, but it would have miniscule power and torque and would probably need a transmission to keep from stalling out - very poor performance.