The 20% gain is presumably relative to the conventional base model with a naturally aspirated V6 and a five-speed slushbox.

The mild hybrid system alone will not deliver gains that high. It must be combined with engine downsizing, i.e. lopping off a couple of cylinders (V6 to I4 w/ balancing shafts) and adding a turbo, preferably homogenous GDI as well. Adding gears to the transmission is also desirable. The electric motor can mask turbo lag and provide transient boost torque at low RPM such that the entire system can deliver the same performance characteristics as the one in the base vehicle.

GM bashers, start your engines!!!!

Rafael - the 20% is also a numbers game. The comparison is between a V6+Auto trans (as base) with torque converter and an I-4 with auto trans and torque converter, with the vehicle having low rolling resistance tires, aero treatments and all that stuff. So, you are absolutely correct. The fuel economy improvement from the hybrid system alone is not more than 10%. The same was the case also for the hybrid Civic, but that's how the game is being played.

With this system I can see them closing the valves, and to roll forward just making the engine go around without starting. This is not as efficient, but it means that they don't have to add the expense and complexity of an additional clutch or speed and gear matching system.

-Michael

Harvey:

Because large organizations have a great deal of institutional inertia. They also have those massive legacy costs (pensions, health care) for hundreds of thousands of retired workers. Their labor costs thus eat into the R&D money that would otherwise go into new products. But then, we've been over that ground before.

I think you guys are underestimating the importance of this. Considering the existing mild hybrid system GM currently makes, it seems more than reasonable that a 20% increase in fuel economy can be achieved, and over 100,000 for just this one type of hybrid allows them to get significant economies of scale, and mild-hybrids are significantly cheaper anyway.

Considering this is comming along with the introduction of the two-mode hybrid and the volt (wich is essentially the first mass produced electric car, as the electric is the only thing providing power to the wheels, which allows you to put whatever engine you want, even a fuel cell, and allow them to opperate always at their peak efficency), GM is really putting some signficant effort into hybrids. They're really the only ones after toyota who have put a signficant effort into hybrids.

Bob Lutz wrote a whole page in "Newsweek" a couple
of weeks back, about how he was convinced that the future
of the car industry lay with driving the wheels with electric
motors , and not with the ICE . what with this post and the fact
that GM are spending 690 million on a new diesel engine
plant , it makes me wonder, does Bob still work for GM !

Is this GM's Plan A? I hope they have a Plan B.

SJC:
The volt's innitial production run will be 60,000 per year, which is 12 times the innitial production run of the Prius. Honda stopped producing the Insight and hybrid Accord. Also, the return on investment for a hybrid drivetrain on an SUV or truck are better than those for small cars, and the majority of gasoline consumption in the US is from trucks/SUVs. Given all that, how do you figure GM's not taking this seriously

It remains to be seen how many Volts will be produced, if any. The number of large hybrid SUVs sold this year will be few. The number of BAS cars sold so far are few. The numbers speak for themselves and the marketing press releases seem to go on forever.

@Angelo
Fuel cells will prove to be a non starter for passenger sedans. Ballard Power systems who've been working to supply the automobile industry for what seems like forever dumped their passenger vehicle business a few months ago to concentrate on transit vehicle powertrains, so much for fuel cells being a viable candidate in the short/medium term.

Regarding these BAS systems. Similar to Honda's IMA, Integrated Motor Assist, was introduced first with the Civic and then with the Accord. Honda and its customers, who, unwittingly, were the guinea pigs for the major field testing found the system not to provide the benefits expected particularly in the colder climes and the Honda Accord hybrid ran only for two model years before being discontinued after the 2007 year. It's a fact, any uninsulated battery box will suffer from 'cold soak' when left outside in the open for long enough in the snow belt and leave the car as a Hybrid in name only. The Panasonic Battery site displays the temperature/power curve for the NiMH battery chemistry showing the drop off at -10 deg C, it's brutal. The Prius is affected to a much lesser degree since its modus operandi is to run the ICE, which is only partially coupled to the wheels, at the lowest possible speed at all times. By supplying power at almost the lowest engine speeds but at commensurately higher torques, before the onset of lugging, the system is able to minimise the effect of friction per engine revolution. This is full hybrid system is also implemented in the Ford Escape I should mention.

I believe disappointment in the mileage from the mild hybrids not living up to expectations was damaging to Honda's future prospects of selling to these owners later on so they quietly took the HAH off the market. That's my opinion anyway. In any event I had been posting about why this IMA was not a particularly good system from the electrical engineering perspective at least three years before on the Honda Civic Hybrid board. Anyway you'll see the arguments Toyolla2 was advancing in the Edmunds board at the time if you're interested. After I made the case to one owner he managed to have all his posts removed from the board which kind of killed the thread. I didn't think he would take it so badly. I lay off those hatchet jobs today. Although sometimes it takes an AXE to get peoples attention.

Accusations of GM bashing, well don't look at me. I want GM to succeed. Heck in my immediate area a major supplier to the Big three just closed shop let 800 people go. Two years ago there were 2000 people working there. And that was just one of several companies that have had major layoffs here in the past year. Despite taking hundreds of millions of dollars in inducements from our government to set up shop here in the first place.
So I want to see GM retain its customer base particularly from those Asian companies that are allowed to ship cars in by the boatload. It has to be making the right decisions . Sound decisions. This BAS idea is just terrible. It continues to perpetuate the large gasoline engine with equally large and complicated stepped transmissions for channeling power to the wheels, irregardless of the fact that alternatively controlling electrical power instead of mechanical poer is a comparitively simple matter. Control of a hundred kilowatts can fit inside a shoe box and connect to an induction motor on the transaxle differential. Job done.
The mechanical method requires variable rpms with variable torque and those torque reactions have to be nursed all the way from the engine block mountings to the transaxle supports with special considerations all the way through to prevent sending powerful vibrations into the body frame. A seies hybrid setup gets you away from all that. Then again there would be no DSG with its own ECU which no transmission shop will understand when you take it there. Here's a scenario - It could be a mechanical problem or it could be an electronic sensor problem with the DSG. How about we replace the whole thing Sir that way we'll be sure. Er... would you mind if we just run your plastic now Sir it's not going to be cheap and we don't want to have to hang on to your car do we Sir! Who wants that outside warranty ?
In the industrial setting involving the machines I helped design we sometimes used 200Hp drivelines. But even if it was only 60Hp the procedure was standard. Connect the motor to the controller, download parameters. Tune. Test. Job done.
But in the auto industry -with these announcements- you would think they were launching the damn space shuttle.
T2

Somehow the announcement lacks the impact that would get me excited. They need to get more weight reduction ideas going to have a more attractive offering. A hybrid should be smaller, lighter, more efficient, and more reliable. The age of the lumbering giant is over.

Doggywood:
I've read 60,000 from Bloomberg News, but also 10,000 from an automotive blog which was more recent. Even still, the Toyota only produced 5000 priusus in it's first year, and the volt is easily as revolutionary.

Also the idea that mild hybrids just aren't "serious" hybrids is a pretty dumb idea--it's comparing apples to oranges. One is a highly expensive, complicated drivetrain, which gives a large improvment in mileage. The other is a relatively simple, relatively cheap drivetrain, which provides a much more modest increase in mileage. I haven't crunched the numbers, but it's certainly possible the mild hybrid can give you a better return on investment.

Also, while the innitial production of the two-mode hybrid will be 10,000 per year, that's only on two different models. It's going to be available on three more models by the end of the year. I'd bet that they're going to increase that production some time in the future, similar to what they did with the BAS.

Every time GM does something, you get people like Treehugger and Lulu that'll either say that they're not doing enough, or that they're not actually serious enough. If Toyota on the other hand does something, it's the best thing since sliced bread.