[FME]

No surprise here. Remember, they grabbed an off-the shelf engine to minimize cost and R&D for this car.

 

[RRRB]

It is a good decision by gm to keep the car closer to standard ICE systems. That gives the greatest flexibility over the Volt development cycle. It also makes the Volt maintenance more familiar. The Atkinson cycle can be a later generation.

One cannot do every new thing in a single step.

 

[Rashiid Amul]

GM engineers are not dumb. They have their reasons to use Otto over Atkinson. I'm just thankful they are making this car at all.

 

[MikeR1]

If they are going to spend billions on R&D perhaps they should have gone for the gold. This seems like a strange engineering decision when they are trying to make a very efficient car. Albeit, some may say it is an EV with a generator so the generator efficiency doesn't matter. I would like to be able to tell people that even in CS mode the Volt can get 50-60 MPG and this seems to all but throw that thought out the window.

 

[RRRB]

The Volt generator will also be used as a common part as it will also be the powerplant for the high volume Chevy Cruze.

That last sentence is remarkable. I am not sure what it means.
Any more details?

 

[RRRB]

4 MikeR : If they are going to spend billions on R&D perhaps they should have gone for the gold. This seems like a strange engineering decision when they are trying to make a very efficient car

I'm sure gm enginers have considered Atkinson, if for no other reasons than that it is in the Toyota and their own trucks. There probably details having to do with acceleration in CS mode, or production, or something else we haven't yet thought up

The good part is that if it is a good idea it still can come, even if not within generation one.

 

[Genfixer1]

RB : The Volt generator will also be used as a common part as it will also be the powerplant for the high volume Chevy Cruze.That last sentence is remarkable. I am not sure what it means.Any more details?   (Quote)

I believe he means that the 1.4L engine used in the Volt to drive the generator is the same engine as is used in the conventionally powered Cruze. This choice was clearly to minimize development costs & reduce component costs for the volt.

 

[JohnK]

I found this quote on another site, originally posted I suspect in Dec. of 2008. "The Cruze will be built in Ohio, and it will go on sale in June 2010 as a 2011 model. Although Chevy is mum about the subject, sources tell us the U.S. Cruze might use a 1.4-liter direct-injected turbocharged 4-cylinder that achieves 40 mpg on the highway."
That 1.4 liter engine sure does sound like the Volt's ICE, minus the turbo.

 

[Jim I]

Other than the MPG during charge sustaining mode, what else is affected by this decision, related to the Volt?

IMHO, this had everything to do with the short timeline to production the Volt has faced from day one. They had enough hurdles to overcome, without adding a different style ICE to the mix.

 

[Xed1]

I'm guessing it has more to do with the potential use of the engine in multiple vehicles.

They just sat down at a table a long while ago and said "ok, what engine do we already have available that will work for the Volt but keep in mind that we need to save some money here so if we can use 1 design for 2 cars instead of 2 designs for 2 cars then it will save us money. And remember we're bleeding money here folks."

This is just one of the compromises that it has taken to try to get the Volt on the showroom floor which is almost all that matters. Chalk it up to the nature of gen1 tech and hope for better things in gen2+.

 

[Tagamet]

RB :
I’m sure gm enginers have considered Atkinson, if for no other reasons than that it is in the Toyota and their own trucks.There probably details having to do with acceleration in CS mode, or production, or something else we haven’t yet thought up
The good part is that if it is a good idea it still can come, even if not within generation one.  

I totally agree with all your posts so far today. I think the GM engineering team is top shelf and may well want to minimize the learning curve for the dealership's garage crews. They are going to have to receive a lot of training even as it stands now.
Be well,
Tagamet

Let's Just Get The Volts' Wheels On The Road!!**********NPNS

 

[Tagamet]

Jim I : Other than the MPG during charge sustaining mode, what else is affected by this decision, related to the Volt?IMHO, this had everything to do with the short timeline to production the Volt has faced from day one.They had enough hurdles to overcome, without adding a different style ICE to the mix.  

I agree, they were probably reading the sign on the office wall that said Let's just get the Volt's wheels on the road! (lol)
Be well,
Tagamet

Let's Just Get The Volts' Wheels On The Road!!**********NPNS

 

[DrG5]

Ummmm. Y'all realize that the Volt is just another GM epic FAIL in the waiting right?

 

[Tagamet]

DrG : Ummmm. Y’all realize that the Volt is just another GM epic FAIL in the waiting right?  

PDNFTT
Be well,
Tagamet

Let's Just Get The Volts' Wheels On The Road!!**********NPNS

 

[dagwood55]

This would help explain the lousy charge-sustaining fuel economy.

 

[nasaman]

I'm curious as to whether the Otto cycle's different combustion/valve timing allows it to run any smoother or quieter than an Atkinson engine?

 

[loboc2]

Thanks fo this one Lyle. I was getting quite tired of hearing about Atkinson.

Atkinson cycle is less powerful than Otto because the intake charge is mixed with more exhaust. I am thinking that Otto was used for this reason and because the engine is 'off the shelf'.

Since the generator will not be used much by ~80% of drivers, it makes sense to use less expensive components rather than exotic ones. Yeah, they could've done a diesel or turbo or wankel or turbine, but, a plain ole normally-aspirated ICE is much simpler and less cost. Buy a Karma or Converj if you want higher end. At the end of the day, Volt is a Chevy.

With the additional battery capacity, Volt's AVERAGE mpg will be much higher than Prius. Even plug-in Prius. The shoot-out will be 2011 plug-in Prius vs 2011 Volt.

May the best car win!

 

[DrG5]

Rashiid Amul : GM engineers are not dumb.

GM management, on the other hand . . .