First Look: GM hybrid SUVs coming at the right time
Thursday, August 09, 2007

By Don Hammonds, Pittsburgh Post-Gazette

Timing is everything in the car and truck business.

Introduce new products at the right time, and you just might sell a slew of them. And that's what might happen to General Motors.

Against the backdrop of anguish over rising fuel prices and falling SUV sales, GM is introducing two new full-size hybrid SUVs, the Chevy Tahoe and the GMC Yukon.

Both get about 25 percent better fuel economy in combined city-highway driving, and about 40 percent better mileage in city driving. Although figures have not been set by the EPA, GM said the pair could get about 20 mpg in the city, about 22 on the highway, and about 21 overall.

While those figures may not seem like much in the days of hybrids that get 50 mpg, they certainly look good compared with other SUVs.

And remember, we are talking about two really big trucks here. They can haul seven passengers with all their cargo, and tow 6,000 to 6,200 pounds. They also have the traction benefits that come with all-wheel drive.

Competitively, that makes these two far and away the most economical full-size SUVs around.

Power comes from a two-mode hybrid system. That is, the engine has two electric motors instead of one. That allows for more flexibility and more options to save gasoline.

The SUV runs on electric power only, engine power only (a 6-liter, 332-horsepower V-8) or any combination of engine and electric power. In lightning quick calculations, the SUV automatically decides what is needed.

The active fuel-management system allows the engine to shut down some cylinders when strong acceleration is not needed.

The system also has electric power steering instead of a belt-driven system that uses more gas.

Other steps intended to lighten the weight of these SUVs include changes to the seat design and lighting fixtures, aluminum hoods and liftgates, lightweight wheels and low rolling-resistance tires.

Driving the hybrid Chevy Tahoe proved to be much like driving any Tahoe. It's quiet, comfortable and easy to handle in traffic.

As you drive, a gauge helps you obtain the best mileage if you keep the arrow indicator in the noon to 2 p.m. position. If you're curious what the truck's hybrid system is doing, there's an easy to understand graph on the navigation screen that illustrates which parts of the system are working and under what conditions. That's better than the bewildering bar graphs and charts used in other hybrids.

Although the automaker has yet to announce prices for the hybrids, I expect them to be $1,000 to $2,000 more than a conventional model.

Timing is everything in the car and truck business.

Introduce new products at the right time, and you just might sell a slew of them. And that's what might happen to General Motors.

Against the backdrop of anguish over rising fuel prices and falling SUV sales, GM is introducing two new full-size hybrid SUVs, the Chevy Tahoe and the GMC Yukon.

Both get about 25 percent better fuel economy in combined city-highway driving, and about 40 percent better mileage in city driving. Although figures have not been set by the EPA, GM said the pair could get about 20 mpg in the city, about 22 on the highway, and about 21 overall.

While those figures may not seem like much in the days of hybrids that get 50 mpg, they certainly look good compared with other SUVs.

And remember, we are talking about two really big trucks here. They can haul seven passengers with all their cargo, and tow 6,000 to 6,200 pounds. They also have the traction benefits that come with all-wheel drive.

Competitively, that makes these two far and away the most economical full-size SUVs around.

Power comes from a two-mode hybrid system. That is, the engine has two electric motors instead of one. That allows for more flexibility and more options to save gasoline.

The SUV runs on electric power only, engine power only (a 6-liter, 332-horsepower V-8) or any combination of engine and electric power. In lightning quick calculations, the SUV automatically decides what is needed.

The active fuel-management system allows the engine to shut down some cylinders when strong acceleration is not needed.

The system also has electric power steering instead of a belt-driven system that uses more gas.

Other steps intended to lighten the weight of these SUVs include changes to the seat design and lighting fixtures, aluminum hoods and liftgates, lightweight wheels and low rolling-resistance tires.

Driving the hybrid Chevy Tahoe proved to be much like driving any Tahoe. It's quiet, comfortable and easy to handle in traffic.

As you drive, a gauge helps you obtain the best mileage if you keep the arrow indicator in the noon to 2 p.m. position. If you're curious what the truck's hybrid system is doing, there's an easy to understand graph on the navigation screen that illustrates which parts of the system are working and under what conditions. That's better than the bewildering bar graphs and charts used in other hybrids.

Although the automaker has yet to announce prices for the hybrids, I expect them to be $1,000 to $2,000 more than a conventional model.

http://www.post-gazette.com/pg/07221/808031-97.stm

 

Sounds good. When are they going to be available?

 

why did you repeat the story in your post?

 

i dont get it why has gm been what to me so late to the hybrid market. not only that but how many hybrids do most company's have 1? this is going to be what gms 3 or 4th

 

GM's 2 mode system is THE most advanced hybrid powertrain on the planet. It puts all others to shame. In addition to the V8 RWD version there will be a FWD v6 version and also a FWD i4 version coming EACH of which will be more advanced than Toyota's synerdrive system.

 

When will the two-mode hybrids come to passenger cars?

 

I didnt repeat the story, I just copied and pasted the information and included to link where it came from.


I think a Tahoe getting near 20mpg in city driving is incredible. My 03 bonneville is only averaging 15-16mpg in the city.
Now GM needs to get this technology downsized into passenger cars soon.

 

Likely about the same time as the Volt hits the streets (2010).

 

Hows so? And how is it different to the other hybrid systems other car companies use? (i'm not trying to start an argument, I just really don't know)

 

As the name implies, there are two modes - a "power split" mode that's very similar to Toyota's Hybrid Synergy Drive, and a parallel mode that runs one or both electric motors in parallel with a stepped-gear automatic transmission. In (very) rough terms, it's a bit like a combination of a Toyota hybrid and a typical four-speed auto.

Power-split drivetrains are mechanically simple and rather efficient from a standing start and within a narrow speed range, but step outside of that range and they actually go downhill in efficiency rather fast (remove the HSD system from a Prius and it'd achieve better economy in typical highway usage). Parallel hybrids suffer from unimpressive low-speed economy, as they still require the use of the IC engine to launch from a stop, but they can definitely offer some performance and economy benefits throughout a wide range of operating speeds. The GM two-mode system offers the best of both worlds, although it's horrendously complicated; I'd go so far as to call it the most complex piece of technology ever implemented in a mass-market automobile.

 

Like what Eric said . I don't know the specifics, but I've been told (by ppl who know) that the Toyota system is very crude, from an engineering point of view. Kind of just thrown together for the tree hugging brownie points. Given how much PR it's got them, I can't say it was the wrong move, but GM's system is far more advanced, hopefully they get their due credit and some tree hugging brownie points.

 

Makes sense and I hope that's true. GM needs the hybrid system that is far and away better than the rest. Will it help them sell more SUV's I'd say it can't hurt.

 

Anybody with a decent understanding of engineering should be extremely respectful of Toyota's system, as it's by no means "just thrown together". The HSD is indeed the most sophisticated chunk of powertrain engineering yet assembled into a production car. As I said, it's mechanically simple (just a small IC engine, a couple of motors, and a planetary gearset), but it more than makes up for that in the stunningly complex electronics that are required to balance the energy flow between the two motors and the battery pack.

Where the Prius falls short is with a battery pack that's too small for effective plug-in use, and with an overall system architecture that's poorly-suited to driving at steady high speeds.

 

ok i apologize.. you didn't repeat the story.. the story does repeat though

 

$1000-$2000 premium for the 2-mode? I really doubt it will be that cheap, but if GM does manage to bring the hybrids to market at that price, they will easily sell all they can make.