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GM Saturn Aura Greenline Hybrid on Sale in 2006

The current Greenline BAS hybrid powertrain. Click to enlarge.

GM will have its Saturn Aura Greenline Hybrid sedan on sale by the end of 2006, according to Jill Lajdziak, Saturn’s general manager. Saturn introduced the Aura hybrid during the New York International Auto Show. (Earlier post.)

The Aura uses the same hybrid powertrain as the Saturn VUE Greenline hybrid: a 2.4-liter Ecotec engine with a Belt-Alternator-Starter (BAS) system augmented with a 36-Volt NiMH battery pack.

The hybrid accessory drive. The dual tensioner assembly that controls the motoring and generating loads is patent pending. Click to enlarge.

Functionally, the VUE hybrid system offers start-stop and regenerative braking—features expected in a simple Belt Alternator Starter system. GM, however, developed a dual tensioner assembly for the hybrid accessory drive (the motor/generator package) that will transfer a small amount of torque to the drive system for very brief periods of time.

The assembly combines an hydraulic strut tensioner and a friction-damped rotary tensioner on a common pivoting arm to the control the bi-directional loads (motoring and generating).

This assistance takes three forms: electrically motored creep at startup, light power assist during acceleration, and light electric mode during deceleration.

The system consists of six elements:

  • The electric motor/generator unit that replaces the alternator, and is capable of 156 Nm of auto-start torque;

  • Engine-coolant cooled power electronics that control the motor/generator unit and provide 12-volt vehicle accessory power;

  • A Cobasys NiMHax 36-Volt NiMH hybrid battery pack capable of delivering and receiving more than 10 kW of peak power;

  • An engine control module;

  • An engine accessory drive with new, dual-tensioner assembly and cord belt that enables transfer of motoring and generating torque;

  • Hybrid-enabled Hydra-Matic 4T45-E electronically controlled four-speed automatic transaxle that includes an auxiliary oil pump and unique hybrid controls.

GM is using the BAS-based Greenline hybrid system to try to deliver a simple hybrid architecture flexible enough—and at a sufficiently low cost—to implement globally on a broad spectrum of both powertrains and vehicles.

The Saturn VUE hybrid offers an estimated 29 mpg US combined and is priced at less than $23,000, compared to the Ford Escape hybrid with 33 mpg US combined at a starting price of $27,500. The Toyota Highlander and Lexus Rx 400h both are rated at 30 mpg US combined, and priced at $33,000 and $48,500 respectively.

GM has yet to indicate performance specifications on the Aura Greenline or pricing.



I remember when solid-state was the buzz word and manufactures would put a diode in a blender and call it a solid-state blender. No different here... GM is going for the buzz word of the day..


Just waiting for the hippies to start chiming in, claiming that a mid-size and adequately powered vehicle that will be on the market before the year is over for about $23k is a horrible thing, and how GM is the devil's instrument of worldwide destruction......let the entertainment commense!


". . .a simple hybrid architecture flexible enough and at a sufficiently low cost to implement globally on a broad spectrum of both powertrains and vehicles."

OK, if this allows GM to have a hybrid option on every vehicle in their lineup by 2010, then I'll give them a golf clap. Until then I'm calling GM management a bunch of junior varsity, Toyota-following wussies.


How is GM "following" Toyota if they are taking a significantly different approach towards hybrids? Do you think that Toyota invented the concept of the hybrid or something?


The prices and performance here were listed for the VUE. This didn't say anything about the Aura as to performance, mileage, and price. So, we hippies can't chime in yet.

Except to say that I have little use for any of the SUV offerings, regardless of manufacturer. As far as having 4 wheel drive, my wife would feel more comfortable here in the mountains of Colorado to have a 4 wheel drive during the snow season. I have a Prius. If I am to replace our Subaru, it will probably be a matrix when it comes out in hybrid form.

I don't think that the VUE or the Aura will be a horrible thing, I'm just skeptical about the potential success of marketing a poor man's hybrid. It's still a market niche with players who are willing to pay a significant premium for the best technology. When Toyota hybridizes their entire fleet, will GM be able to compete? By that time, Toyota will have reduced the differential between standard and hybrid. They will also have the better technology.

I am not saying that GM is the devil, but I am saying that they better be in a position soon to compete head to head with Toyota or they will end up in bankruptcy.

Ang's Jello

Like you don't have your own knee jerk reactions pre-programmed into your psyche Angelo. Let's give it a try....

I think this hybrid thing is great, but it's just precursor to GM's ultimate return to supremacy via the hydrogen fuel cell vehicle.

Always Room For Jello

Speaking of GM and fuel cells Ang's seem to be right on top of GM's plans. Did you see this quote today from Larry Burns, head of GM R&D...

"The world doesn't need another niche powertrain," said Larry Burns, GM's vice president for research, development and planning. "We need a solution that will solve energy issues and allow us to grow. The key is durability, cost and performance, and we've made dramatic progress." "Fuel cells and the hydrogen economy are absolutely the next great race for industry," GM's Burns said.


Hydrogen will never solve our energy issues. If anything, it will exacerbate them. Yes, we "need" an energy solution. But it isn't coming from hydrogen, a storage medium that still has an energy return of less than one.

GM would be better off pushing for universal health care. Now, there would be a cost savings and would put them on a more equal footing with the Japanese.


GM's "significantly different" approach to hybrids is less efficient and requires less engineering and manufacturing expertise than even Hondas.

And 35mpg out of a tiny little Aveo? Pfft. GM isn't interested in pushing the envelope. They're interested in riding coattails and cashing in on big, inefficient vehicles.


I feel like I'm beating a dead horse, but let's recap this wonderous hydrogen idea:

1. Extracting hydrogen from other elements through an energy intensive and yet unproven process
2. Compressing it into a liquid form through an energy intensive process
3. Transporting it using trucks to the hydrogen stations
4. Transfering the hydrogen to holding tanks at the stations
5. Making fuel cell vehicles drive to a hydrogen station only to transfer it to their own tank
6. Turning the hydrogen into electricity to power the electic components of the vehicle.

Yeah, really sounds like an efficient process.......

It is being pushed because it extends the use of fossil fuels much longer, as people just assume hydrogen to come from water, oblivious to the fact that it will come from the same fossil fuels that we are trying to get rid of. Plus, all of the oil companies are trying to find an excuse to tap into the huge supply of methane hydrates.


I wouldn’t be so quick to throw out the hydrogen fuel cell just yet. Most people in the field will tell you that their window is approximately 15 to 20 years away, but that it is VERY PROMISING technology. Every few weeks you can read about break throughs in fuel cell research.

This is also why so many people are excited about PHEV’s. They are a great STOP GAP, until the fuel cell can pay its own way! Plug-ins can catapult us to very high mileage (and low emissions!) very quickly, using existing technology. Half the people who commute, drive less than 25 miles to and from work. They could start going from, say, 23 mpg to 90 mpg and more.

Plug-ins also help with the fuel cell car design itself. Much of the design work for electric/ hybrid cars, contributes to the design of the fuel cell vehicle, which will have the same concepts: electric motor, more efficient mechanicals, and electronics, i.e. drive by wire, etc.

John W.

George: you post a reasonable piece of thinking. The tech in fuel cell cars is going places...but the problem with the whole hydrogen infrastructure if it ever comes out is the absolutely huge and inordinate amount of energy it takes in the first place just to split the hydrogen from the O2. It takes huge and massive amounts of energy at present, to the point that there is absolutely no advantage in the end, to be the most positive.

Sure the cars make water when they drive on the road: what about the kazillion tons of fossil fuels it will take to make the hydrogen and compress/store it, etc, at the refinery? Either a process has to develop to split the hydrogen out that is way cheaper/more efficient, or we need the whole thing powered by green power (wind, solar, etc), which isn't going to happen anytime soon b/c of how many turbines would be needed. The way to go is all electric with the new motor, battery and cap technology already out and coming out, and composite technology. With the right set up you could charge it right at home and it would pay for itself: solar is getting cheaper, consider the SunBall Solar Appliance. But we're off topic I guess.

I don't like GM but I am still applauding this development with the Aura. It's definately a step in the right direction and a whole lot better than no step at all! Surely, no one would argue with that?


Angelo: you miss the point. GM bets on SUV and hydrogen fuel cells for one same reason: they are both expensive and wasteful. Perfect set to skim high profit margin.

Aura hybrid technology is at least twenty years late. Toyota leap-frog it, GM no.


I'll agree that GM's approach has been flawed, but I still do not understand why GM takes the brunt of the abuse. They are a corporation, not a government. Their goal is to figure out what the public wants and make a profit from it. A couple years ago, there was no substantial proof that hybrids would catch on. What GM did know was that the government was willing to spend a ton of money promoting fuel cells, and that consumers were still infatuated with SUVs. If anyone is at fault here, it is our own government, and ourselves.

At least GM has developed their 2-mode hybrid drive for their full-size SUVs. What has Ford done with their mid-size or large SUVs? Dodge may have a hybrid Durango a year later, but have announced nothing with Jeep. Even the almighty Toyota has not announced anything for their larger SUVs.


Just to clarify an earlier statement - yes, fuel cells are a promising technology, but my point is that they have NO PLACE in vehicles. It's just plain dumb. Why bring the hydrogen to the car, only to turn it back into electricity? Larger scale fuel-cell "power plants" that are located wherever hydrogen can be produced and then pump that electricity into the grid would be a much better solution. It scales better with PHEVs and the advances in sugars-to-hydrogen concepts, butanol production (which gives off excess hydrogen) and other FT methods that produce excess hydrogen. Sure, our electrical grid may need some significant upgrades to handle this, but this is surely a less intensive effort than building this hydrogen network.

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