Angelo

it is very Clear that I have an anti-GM sentiment and for good reasons, but I praise their effort on the Volt no problem. I just have worries that because of questionnable technical choices that put together will result in a very heavy car, that will have hard time to get what they claim and wll be expensive, But I am quite impatient to see the result indeed.

if the 1.4 Liters is lighter than a 1 liter fine, but the weight is not the main thing, dowsizing is a way to reduce to reduce pumping losses, friction, and reduction of number of cylinder reduces thermal a losses as well (for a agiven size) that's what fiat and peugeot or honda are doing to reach better efficiency.

Stan Peterson, before blaming my attitude you should look at yours, you keep spreading your political views and insulting californian people as well as whom who are not from your politcal side, as a matter of fact I am californian and I am not on your political side. And anyway you are so convinced that the american auto industry is the finest in the world, right and that's me who is close minded..right

An analysis of trying to climb mountains when the SOC is already at 30%, would require a battery recharger to drive full 53KW rated generator output into the battery for extended amounts of time.

Absolutely correct. People who say Volt engine should be 25 kW don't get it. And thank you Mr. Peterson for correcting other misinformation. However, I disagree about the 1.0L turbo. It can deliver 53 kW just fine, this decision was driven purely by cost. GM will use 1.4L engines in other US models but not the 1.0L. A custom US 1.0L engine line just for the Volt or importing it from Europe with the euro at $1.60 are both cost-prohibitive.

Anyone griping about the 1.4L should realize a couple things. First, the added weight (if any) will not measurably affect EV range. It may affect the 50 mpg, but does that really matter? A normal 25 mpg sedan uses 500 gal/yr to go 12,500 miles. A typical Volt driver might use gasoline for 2250 miles/year. At 45 mpg he cuts his gas consumption 90%. At 50 mpg the reduction is 91%. Let's try to keep our eye on the ball, folks.

There is a really informative article at gm-volt.com on the topic. http://gm-volt.com/2008/07/26/gm-explains-why-the-14-l-ice-range-extender-was-chosen-for-the-volt/

GM explains their choice of 1.4 liter over 1.0 liter turbo arguing the 1.4 liter is actually more efficient in the steady state mode the engine is going to run, it is lighter, quieter and it cost less.

Also very interesting in my opinion they say “Nitz also states that GM has refined the charging window of the pack as 35% to 85%, whereas previously GM had said it would be 30% to 80%. He does say though that the battery could be discharged below 35% if it has to on rare occasions, but that when steady state resumes, the battery will recharge as the engine then produces more output than the car requires at that time.” So this rare occasion is probably if the gasoline tank is empty. In that case you may press a bottom in order to get the 35% of the remaining kWh to get you to the nearest gas station with a warning possibly that this is emergency only and that the battery will be degraded when you do it.

It makes sense. A turbocharged downsized motor is only good in standard ICE configurations because most of the time you are not using anywhere near full output so the smaller displacement for idle and very low power (like cruising) needs little fuel and when power is needed the turbo-charged engine can provide power equivalent to a larger motor. At full output power a turbocharged engine will have higher SFC than a non-turbocharged engine of equal horsepower but the naturally aspirated engine will use more fuel at idle due to larger displacement. In a generator application where you will not be "idling" the engine as you would in a standard ICE powered vehicle so therefore the turbo charged vehicle loses its advantage.

As an electro-mechanical engineer and a Honda Insight owner, I too had reservations about the selection of a 1.4L engine. After visiting the GM site that explained the rationale;

- For one thing, per Nitz, "the 1.4L NA four has better brake-specific fuel consumption than the 1.0L turbo when used in steady state mode, as it will be in the Volt application."

A positive point for the 1.4L

- Also Nitz claims the four cylinder engine will provide for a smoother transition from EV to range extension saying "the objective is to keep the engine off and when the engine comes on, you don’t want to know it’s on. You want it really smooth and four cylinder is smoother than a three."

Not much of a point at all. My 3 cylinder Insight engine engagement is almost imperceptible. And I'd be willing to bet a large percentage of Volt owners would want to know when they start consuming gas instead of remaining on electricity.

- Nitz also noted that the four cylinder has a lower cost and that when the turbocharging architecture is added to the 3-cylinder engine, the non-turbo four cylinder engine setup is actually lighter.

Both positive points for the 1.4L, if true.

The real point is "what are the assumptions by which power requirements are determined?". The starting point should be the power requirements for 60mph straight and level driving, which would be far, far less than 53kW. Some amount of hilliness can be factored in, though it must be remembered that hills have a downside as well. Recharge time is the next factor; what assumptions has GM made and on what criteria? Getting the car back to where it can be recharged via the grid would seem to be a more plausible criteria that recharging it as fast as possible using gasoline.

I would strongly disagree with the assumption by a couple here that basing the engine sizing on starting a mountain climb with exhausted batteries is a priority. I don't see this as a frequent occurrence with most potential Volt owners, and in those infrequent cases, climbing a mountain at 55 mph instead of 65 mph is hardly a hardship. I have run into this about twice with my Insight, and much prefer to have the 1.0L engine for the 99.9% of the time that it is better suited than a larger engine.

I have a feeling that the 40 mile EV range GM has hung their hat on along with their buyer performance preference guessing is going to raise the price beyond most buyers' budgets, so this will simply be a low volume green front for them (unless they are able to quickly produce another PHEV in the $20k range). Having an option to have a smaller battery pack that gives 20 miles EV would drop the price appreciably.

I am not fully convinced by the argument of GM of 1.4 versus 1.0, but they had to justify their choice, the real reason is that they have other use for the 1.4 when they don't for the 1.0 so the choice is easy to make. At best they will sell 100 000 Volts a year (until they find a way to bring the price below 25K without loosing moneay...) so 100K is not a volume than can justify the development of a new engine.

Like Stan Peterson said (sometimes he is right) this is a first platform, if they are successful they will developp the perfect engine for this type of vehicle, maybe a free piston HCCI or (clean) diesel engine, maybe a micro-turbine with heat recovery.

@ Will S.,
GM may not have as smooth 1.0 L engine as Honda. Also GM may know that there may be some reliability issues with the smaller engines (or with turbochargers) they avoided.
Looks like GM don't want to take chances with ICE, they have already too many issues and unknowns with batteries. It's a very prudent approach after all, they're developing a car to be mass produced, not a technology demonstrator.

The selection of ICE power based on uphill driving makes sense - they want to have a car with the range limited only by the size of gasoline tank, like existing cars, many customers would demand that.
The EREV models with limited range (for mostly city driving) should follow.

MG

It is very clear that GM doesn't have the background of Honda, Peugeot or Fiat in designing small engine, anybody who has drove a Renault Megane diesel with a 1.5L turbo charged diesel would realized how big the gap between european and US technology is, in that matter.

Treehugger,
It's true, US carmakers (excluding their European branches Opel/Vauxhall, and Euro Ford) don't have good small engines (below 2 L).
Until 3-4 years ago there was not much demand in US for them, gasoline was cheap, but now it changed.
In Europe gasoline was heavily taxed, so they needed to develop frugal small engines.
On the other hand US has superior military technology, military bases all over the world, using it they were able to ensure reliable oil supply (didn't Greenspan say that the Iraq war was about oil). Until recently it worked well for US, how it will work in the future, we're going to see.
Another issue is the morality of that approach.

Obviously GM know they can just barely build the Volt, but can't hit all the requirements to make it into a commercial success. On the one hand we can't blame them for these difficulties, but on the other hand no one forced GM into a serial hybrid or bust approach. These are all self-inflicted wounds.

Making the Volt a two-seater sport PHEV would make it lighter.

Maybe if Europe hadn't rolled over and played dead for Hitler in 1930s - there wouldn't have been a European theatre world war - and the Americans would have no reason to put bases there (and avoided the ensuing cold war).

"Then again no one sees the retardation in your comments,"

On contrary, quite a few people do.

On topic: Lutz commented that the 1.0L test engine was coming on rough - meaning the vibration was an issue. The subsequent explanations more than justify the choice. Some people live by projected catastrophe - positive messages are alien to them.

Wow Lulu - it's enlightening to read psycho-babble.

"Maybe if Europe hadn't rolled over and played dead for Hitler in 1930s - there wouldn't have been a European theatre world war - and the Americans would have no reason to put bases there (and avoided the ensuing cold war)."

The war started in 1939, Americans turned their backs on it until 1941 when after their manipulation of oil supplies irritated the Japanese enough to start the war with the USA. Again the USA went to war over oil....

Obviously GM is using this engine because it is coming on stream at about the same time that it is needed for this low volume application. In non-Atkinson, light pressure turbo form, it is the same new powerplant being used for the Cavalier replacement. GM is just trying to keep its costs in check, that's all.

Personally, I'd rather see them invest in a high compression (efficiency)diesel powerplant in a vertical arrangement of two opposed cylinders, with two valves per cylinder, a turbo, and water injection on the 3rd stroke.

That's why we're the dreamers and they're the manufacturers!

No European diesel (or turbodiesel) passenger vehicle engine meets U.S. emissions specs.

It's also unlikely any European gasoline engine meets U.S. emission requirements.

If the 1.4 L engine
1. Costs less and
2. Gets better SFC and
3. Weighs about the same or less
it is the clear choice.
Hill climbing is better.
Reserve power is better.
What’s the minus? More power than needed would result in lower highway mpg? Nope, it has BETTER SFC when running and would likely run intermittently or in severe "Atkinson mode" so it's averags size might be 0.8L.
The minus? The big engine offends.

ToppaTom,
The Minus of larger engine may be that it occupies more room, which ultimately could mean a heavier car (even if the engine itself is not heavier).
But there are advantages as well.

A good point MG. Might take more room. But 0.4 liters is only 24 cubic inches; 3" x 4" x 2". A turbo is larger. An intercooler is larger. One more OH cam is larger.
Besides, maybe they will use the same casting as a 1.0L engine and remove 24 CUIN of aluminum from the bore - umm, maybe not.

I can understand this. It is simpler and more dependable. Saab may produce turbo engines, but that 3 cylinder turbo was from the Geo era and not suited for this. You need to show that the car will run for 200k miles and going with what will work makes sense.