Thats some funny stuff. First of all. Nothing magical about “small” turbo-diesels. All turbo-diesels run similar diesel cycle with very high compression ratio.

Diesel cars are only mildly more efficient than standard gasoline cars. Diesel Fuel in the US has more than 10% more energy per gallon that gasoline. If you go to UK, where there are many Diesel/Gas cars, when looking at equvalent performance and engine technology, the Diesels only average around 15%-20% more efficient, which means more than 50% of this is just due to the higher energy content of the fuel (Yes there are exceptions to this rule). Furthermore, the Diesel Engine option often adds a few thousand to the bottom line.

Diesel engines do not make sense for the United States. Witness the number of canceled Diesel Plans in the past few years. GM is going the risker route, but one that might sell in the US, where-as Diesel is apparently not an option, even for car companys with efficient and clean engines that only need certification.

Total Energy use from Point A to Point B will be exactly the same regardless if you use the Battery Energy at the Start or the Finish.

It is possible that you can operate the ICE is a more efficient band when doing your steady state travel, but the comparison to this is the already insolated by battery engine efficieny, not a standard ICE.

Then there is the very real possibility that you “over” generate your power. IE, you get home with 40% SOC because you ran the ICE too long rather than 30% SOC. GPS tracking and route planning could help elevate this concern, but it seems like a tricky bit of software to allow someone to buy .19 gallons of fuel rather than .2 gallons of fuel. (at best, with a very skillful operator)

In the end, I think way that will be more efficient for almost all drivers is to use battery until it gones, then use ICE. Most drivers wouldn’t be able to adqueately hit the “cutoff” point to get home within the right SOC window, and GPS software won’t take into account the weather, traffic conditions, or your driving conditiongs well enough to consistantly provide better results.

And for the record, GM is actually aiming at a new category between AT PZEV and ZEV. This may give GM additional CARB benifits, or drivers of the Volt addition benifits in some states.

GM – We are tying to get the car to act quiet and respond the way a normal car would

steel- I want my generator running at maximum efficieny, whether or not it makes inherit sense. Show me, the driver, why at a stop light my car is running at 2500 rpm (because I need to bring the battery back to 30% SOC) and I will be fine with it running. Don’t feather it down (lose efficieny) to just feather it back up again (lose efficieny).

The flip of this is when my SOC is 35%, and I hit the accelerator, I -don’t- want my ice feathering up to 4000 rpm to meet HWY passing speed requirements. Leave it alone, and let me the driver know why my engine is staying at 2000 rpm (I have alot of excess charge).

All in all, I am not sure where I am even asking for more noise. Just more information and a willingness to have excess noise (provided I am getting better MPG from it)

I think a forum post is similiar to a converstation, where small gramatical errors are forgiven, provided the meaning is clear.

Which I think it is very clear in the context of the conversation (and topic) which unforuntely spans many many article posting.