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11 April 2006

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.

April 11, 2006 in Hybrids | Permalink | Comments (69) | TrackBack (0)


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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).

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

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.


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?


I don't think anyone really knows how good the baseline vehicle is. It's based off the epsilon platform that the G6 uses, and the G6 may not be getting rave reviews, but it is getting generally positive feedback. Assume the Aura is a decent vehicle to begin with, I think this hybrid can work. If the Aura hybid gets about 160 Hp (seems reasonable) and gets mixed mode driving in the mid to upper 30's, that would still be fairly powerful, and more efficient then almost any other midsize on the road. Assume a hybrid price less then $2000 over the standard, consumers really may save some cash relative other vehicles in it's class.

Anyway, GM and Ford should really be putting hybrid systems on their SUV's. More bang for the buck really. You need less then half the efficiency gain on a SUV to save the same amount of gas that a Prius does over a Matrix/Vibe.


Gas milage will become a more significant factor in the years to come. Just remember the basic rule. Per 100,000 miles, 25mpg means 4,000 gallons, 50mpg means 2,000 gallons. For gas costing $3, $4, $5, and $6 per gallon, this means that costs of fuel will correspond to a fuel savings of $6,000, $8,000, $10,000 and $12,000 for the 50 mpg vehicle as compared to the one at 25mpg.

This is a good start for GM, I welcome it... some on this form would boo anything that's not a Bio-Diesel PHEV Vespa or simular :)

As for efficiency of electric A/C:

The reason an electric A/C *CAN* (but isn't neccesarily) be more efficient than a purely mechanically driven one is quite simple.. mechanically driven A/Cs use a variable RPM design which wastes a lot of the power given to it (an A/C compressor nees to run at a constant RPM(except some newer digital systems that vary rpm by load but that's a different subject), where as an engine's RPMs vary.

So the efficiency of the mechanism that alters this RPM is directly responsible for how less/more efficient a belt driven one would be.

However I paticularly like Honda's approach on the newer civic hybrids, a hybrid A/C comrpessor... it runs off the belt when it can, but when at idle stop, orlow A/C load, or when rnning in learn burn, it switches to electric.

GM is again practicing "Planned Obsolescence", to insure future sales of equally obsolete automobiles.

The 'start/stop' feature should not be considered "hybrid", but will qualify for tax credit or rebate.

GM's grand vision is a future of jam-packed freeways and a miniscule reduction of air pollution when these psuedo-hybrid cars stop in bumper to bumper traffic.

It's some kind of country club joke, like when George Bush was overturning furniture in the Oval Office looking for WMDs; remember that little joke? Well, he was looking for his stock portfolio. Get it? Ahee hee, ahee hee. "Oh Georgie, we do so love your little wittisisms", members of George's country club chortle.

GM's corporate charter should be revoked, it's executive board of directors charged with crimes against humanity.

Why is everyone being so hard on GM? A 20% reduction in fuel consumption without downsizing and/or making it severly underpowered is pretty damn good, in my opinion. Are they better off doing nothing?

There are far too many extremists out there who think we can just shift to a transit structure similar to those made popular on The Jetsons, virtually overnight! We need some realistic steps in the right right direction, and here we have one, and people still complain. If you want people to EMBRACE hybrid technology, you do something like this - start with something reasonable, that costs about as much as a relatively unnecessary navigation option, but has tangible benefits.

As long as GM can keep up with demand, I don't think it's unreasonable to expect up to a quarter of these cars being sold as hybrids.

GM is evil!

GM is the next Hitler!!

GM is going to kill us all!!!

GM doesn't give a shit about humanity!!!!!

GM does however paint their cars pretty colors.
So that makes them OK.

Is there anyone on this board who is going to go out and buy a Saturn?
Alternatively, are there any Prius or HCH owners here and will there be anyone who will buy the 94mpg Prius, if it happens.

No doubt this Saturn Hybrid will be a great innovation, for others. But no one here, I expect. We've already gone way beyond what GM is offering here. Are we now supposed to get enthused about going backwards.

People are hard on GM because they missed the boat and aren't even really playing catchup. If boring sells, this should work.

It's pretty pathetic how some people always feel the need to bring up President Bush when it has zero relevance to the topic.

Good for GM, it's progress. I'm not a pessimist that whines and cries because at things that aren't a huge technological jump. Nevermind the fact that this is only one type of hybrid system GM is coming out with. They have FULL hybrid system, one that are supposedly better than Toyota's HSD (GM says their "two mode" full hybrid increases hwy milage where as Toyota's HSD doesn't really).


That's total vaporware for now, though.

By the time it comes out, Toyota will be on it's 3rd or 4th hybrid generation, have almost its whole lineup available with a hybrid drivetrain, and probably be the #1 automaker in the world. GM will be lucky if it's not bankrupt...

Don't get me wrong, I'd be the first to applaud if GM (or any other automaker) could pull off something really cool in the green transportation area, but I'll believe it when I see it. It's too easy to talk about what's on the drawing boards of the R&D department (I'm sure Toyota has some really cool unreleased stuff too...).

At least if GM hadn't scrapped their EV cars, maybe they could get some kind of halo effect out of it..


As with most GM cars, their most convincing selling point will be price. Because in the mid-size segment, it's going to be fighting against the Camry hybrid, the Altima hybrid (using Toyota tech) and the Accord hybrid.

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