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GM Announces First Production Passenger-Car Hybrid: Saturn Aura Green Line

The 2007 Saturn Aura

At the New York Auto Show, GM is unveiling the all-new 2007 Saturn Aura mid-size sedan, based on last year’s concept car of the same name. Uplevel models of the Aura will feature GM’s first application of a new six-speed automatic transmission mated with the 3.6L DOHC V6.

Later in the 2007 model year, Saturn will offer the Aura Green Line, a 2.4L Ecotec-based hybrid that will use a powertrain system similar to the Vue Green Line. (Earlier post.) It marks the first application of a hybrid powertrain in a production GM passenger car.

The non-hybrid Aura goes on sale late this summer in two trim levels: entry and uplevel. Saturn will offer two powertrains at launch: a standard entry-level 3.5L V6 with variable valve timing (VVT), and the uplevel 3.6L DOHC V6 with VVT.

The entry-level 3.5-liter engine generates 224 hp (167 kW) and 298 Nm of torque. The higher-end 3.6-liter engine is rated at 252 hp (188 kW) and 340 Nm of torque.

This latter engine is mated with the all new Hydra-Matic 6T70 six-speed automatic transmission, the first application of this in the GM Powertrain portfolio. The transmission allows for strong performance combined with strong fuel efficiency.

The Green Line hybrid system, as applied in the VUE, is based on a Belt Alternator Starter system—essentially what underlies a Start-Stop system—albeit one with some modifications that provide a small degree of traction assistance.

This system is GM’s third production hybrid system, the others being the high end two-mode hybrid system that GM will apply first in the Tahoe and Yukon full-size SUVs and the low end micro-hybrid applied in the Silverado Sierra.

Combined with other vehicle modifications to decrease fuel consumption, the Saturn VUE Green Line hybrid delivers an estimated 20% improvement in fuel economy.

GM has not yet announced the level of fuel savings to be delivered by the Aura Green Line hybrid implementation—but the automaker’s choice of a 2.4-liter Ecotec rather than the standard 3.5-liter V6 is an indication that GM may be trying to optimize fuel economy in the model over performance.



I hope I'm wrong, but it sounds like a hybrid for the namesake. A marginal 10% economy gain (like the VUE?) could undermine the public's perception of hybrid technology and its benefit/cost ratio. A 94 mpg Prius does just the opposite.


Not to worry -- the process of "Natural Selection" will take care of GM and others that continue to live in denial.


It is an improvement over a non-hybrid and if it can be classified as a PZEV and can be sold in CA as such then it serves its purpose.

This mod may make sense cost benefit wise where a several thousand dolar premium for a prius can't be recovered in gas savings over the life of the vehicle at current fuel prices.

This could also be applied to most any vehicle in the GM fleet without a major redesign.
with any hybrid system the main gains come in a stop and go driving cycle.

Unless you have an all electric drive that is more efficent than a mechanical coupling (transmission) that allows the engine to run at its most efficent operating point .... a hybrid will have zero advantage over a non in a "normal" for USA high speed long distance interstate driving.

In town the hybrid may have an advantage with the ability to recover energy that would normaly be lost in braking, ideling, and reduce the energy required (from the engine) to accelerate.


10%? The article said 20%. Nice try on GM's part but unless they ramp up to full hybrids they will get left in the dust as "fuel shocks" pile up and consumers start shopping MPG bigtime.

OK in GM's favor this is a good steping stone however because this system is much cheaper and can be adapted to many of their vehicles that use the Ecotec. It uses a 36volt battery pack and many of the accessories are electric rather than belt driven. The R&D that went into the accessories and the start/stop can be carried over to full hybrids. We better be seeing them soon because the cheap gas party is over.


I gave someone a lift to Saturn (for service on their Vue). It was interesting to walk around the lot and see 24/32 mpg stickers on all the windows. For what used to be an economy brand, that doesn't seem that high to me.

(did they have more efficient models, sold out?)


Here are some things to realize about hybrids:

Usually (other than the micro hybrids with 14V starter/alternators) they utilize higher voltage motors & generators. A higher voltage system enables the use of electric air conditioning and power steering units. Electric a/c and p/s are more efficient then mechanical units PERIOD. That gives an additional reduction in fuel consumption (although very small in the overall scheme of fuel consumption for an engine). This does help more than simply the start/stop function of hybrids.

Additionally, this helps to usher in the age of 42V (36V battery) automotive electrical systems. A greater range of power hungry safety/telematics/ and automation systems can be employed with a higher voltage system. I'm not saying cars should drive themselves, but nearly all (sorry, I don't have the stats) accidents are caused by DRIVER error and such additional "guardian" systems could help reduce the chance for error (whether passive or active is a discussion for elsewhere).

tom deplume

Anybody care to give odds on GM going bancrupt before these hybrids go to market?

Lance Funston

The Aura is GM's attempt to reintroduce their Opel cars that are popular with the rest of the world but they claim that "Americans don't want". I'm not hearing much excitement in this forum anyway. I guess we'll see if that's true or not.

I think its a great platform for introducing their BAs hybrid on passenger cars, but I'm not in the market.


I'd like to see some numbers on the power consumption of electric vs mechanical air conditioners. That electric a/cs should use less energy seems non-intuitive to me, considering that an air conditioner is mechanical -- it works on the compression/decompression/moving around of some coolant. In a car, to make an air conditioner electric you need an electric motor to run the compressor, whereas if you make it mechanical you're basically running the compressor off of a belt from the engine, aren't you? So an electrical system has the weight of an electric motor and beefier alternator vs the weight of a belt.

Joseph Willemssen

"a several thousand dolar premium for a prius can't be recovered in gas savings over the life of the vehicle at current fuel prices."

I'm amazed at how persistent this myth is, no matter how many times it's disproven.

At current gas prices, assuming a $4,000 premium without tax breaks, the simple breakeven mileage is roughly 123,000 miles -- well below the useful life of a Toyota sedan.


in terms of which Opels we "want" ... I some smaller ones on the German Opel website. This 6cyl, 252 hp, choice isn't exactly "green." Maybe they think it is a Camry competetor?

It certainly does not position well against the Civic or Corolla, which would make it more of a serious answer to higher prices and global warming in my book.

(The little Opel Agila is more like what we see on GCC ;-)


odograph: Saturn was once GM's innovative small/cheap car division. It had originally quite a devoted following. It along with Saab could have been GM's high-tech innovative divisions, Saturn at the low end, Saab at the high. It along with Saab were in the event ignored and underinvested for years and as a result completely wasted as forward-looking resources, and the reputations of both have plummeted. (You can add the EV1 and the PNGV Precept as more wasted efforts) GM is perhaps finally realizing this, and I hope they can turn the corner. They have some first rate engineers, significant technical resources, but completely incompetent management.


Actauly the hybrid system they are using combined with the new transmission will in fact get it very close to many full hybrids at far less cost and with the ability to ramp it into the millions of units.

The transmission itself trims about 5% off and the new hybrid setup is partway between a micro hybrid and a full hrbid and will get middle ground fuel eff percentages..

Together they are solid. Oh and combined with a fuel eff tuned engine they likely will bring a MUCH higher milage set then the normal version.


Does it accept E85?

To Bryant,
I think the electric a/c is more efficient because:
1) when the a/c isn't in use the belt is still a drag on the engine.
2) the a/c can run with the engine off. (only important for a hybrid)


Wintermane, for what it's worth my prius mpg seems very closely related to the "engine off" time I can manage. That is more than at stop. It is also in mild acceleration, and at steady speed cruising (esp. given a slight downgrade). Do you really thinkthe Greenline can manage that much time "engine off?"

I mean, in order for it to get to Prius or Civic Hybrid territory?

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