GM has selected the ICE

[KariK]

GM has selected the ICE for the Volt:

http://www.greencarcongress.com/2008...-14l.html#more

"GM has selected a 1.4L naturally aspirated engine as the range-extender in the Volt, according to Larry Nitz, Executive Director, Hybrid Powertrain Engineering.

[darthvader420]

I remember hearing the 50 mpg figure being thrown around in regards to the range extender but I think it was supposed to be a 1.0L engine then. Has GM given any new numbers?

[MrBogey]

Well it looks like if google is to believed it'll put out 66kW of power. Fuel consumption in the Opel seems to be around 40mpg.

[Texas]

I hope GM eventually gives us a much smaller ICE option for those of us who don't care if we have to limp around after the electricity is gone. I can get my jollies in full electric, thank you very much. If I have been bad then I can limp around at 50 + mpg. The ICE will be lighter and so will the gas tank and the gas in that tank as will the cooling system, The coolant in the radiator, the oil in the engine pan, etc. down and down we go.

[KariK]

So if the ICE outputs 66 kW, and we assume the generator eats 6 kW, that leaves 60 kW power for the electric motor. That's a bit more than the 53 kW we have heard before. Or will the generator eat more? And does that mean the ICE is only on part of the time at highway speeds, which would increase the effective ICE mpg rating.

So hypothetically if the ICE nominal rating is 45 mpg but it is only on 90% of the time, then the effective mpg rating would be 50 mpg. Is there enough info on this engine and on the Volt to get real numbers on that?

[wtiger]

The ICE only kicks on after the batteries depleted to 30%. If you drive less than 40 miles it should never kick on. I don't know how they're going to run the ICE after that point yet, but I've read that it will have 3 charging points depending on the load. Say it runs at the lowest rpm/highest efficiency point when the load is low. then kicks the generator up a notch to the 2nd rpm point when the load is moderate and the 3rd least efficient point when full power is needed. It seems silly to me to stop the genset once the battery is depleted and simply let it run at it's most efficient setting until the car is turned off, more power is needed, or the battery is recharged; because there is capacity to store any extra energy in the battery and that would reduce the wear and tear on all the mechanical parts.

This is mostly speculation on my part. Except for when the genset will start operating, but in my mind that seems like it would be the most efficient use of a series hybrid. It would make it very efficient and keep wear and tear on the mechanical parts at a minimum.

[darthvader420]

According to this chart on the front page, the ICE will be starting and stopping to meet the demand, keeping the batteries just above the magic 30% figure

[wtiger]

just kind of surprised they would cycle the engine like that. I figured they'd at least let it get up to about 50% before flipping it off. I wonder if they do it like that too extend the life of the battery.

[Texas]

Originally Posted by wtiger

just kind of surprised they would cycle the engine like that. I figured they'd at least let it get up to about 50% before flipping it off. I wonder if they do it like that too extend the life of the battery.

Don't worry, this standard "house furnace" mode is only one of many possible modes. The software guys (and gals) will have to play with the mules for quite some time to come up with different modes of operation that fit under different conditions. For example:

1) Long highway drives - would want a more constant ICE running mode.

2) Extreme driving mode - Hot driving followed by breathers.

3) Limp home mode - Almost home and want the minimum charge when I get in the garage.

4) Quiet mode - no ICE operation desired.

5) Custom selection - driver would like to select a different mode.


Thus, you can see there there's a lot more going on than at first glance. As I like to say, if GM doesn’t provide it... The hackers will!

[McTLD]

I'm certain GM is doing everything it can to make this car acceptable to the general public on the first go-around. I have more hope in that than I do them engineering some modern marvel and screwing it up on a gamble the first time - so the engine thing don't bother me too much. I think if they can get it "right', then we'll see GM dial changes in at all the right areas.