The gasoline version of the 2007 Saturn Aura impressed automotive journalists so much that the car won this year's title of North American Car of the Year. Now it's going green. Making use of the same Belt Alternator System hybrid-lite technology that we first saw in the Vue Green Line last year, the 2007 Aura Green Line is the second hybrid from Saturn, which promotes it as the cheapest hybrid car on the market. In keeping with this mission, there are precious few frills on the Aura Green Line: a basic, easy-to-use stereo and an off-board navigation service constitute the sum of its gadgetry. While its hybrid drive train may not be as sophisticated as that of other manufacturers, the Saturn Aura Green Line does succeed in its mission of delivering significantly improved gas mileage over its award-winning gasoline counterpart.
Test the tech: OnStar off-base
One of the few digital highlights of our 2007 Saturn Aura Green Line was GM's OnStar telematics system, which on our test vehicle included the Connections and Directions turn-by-turn navigation service. Unlike LCD-based systems, OnStar's in-car navigation delivers automated voice-guided directions and text-based information to the car's in-dash display. We resolved to test OnStar to the point of breaking by requesting directions and then willfully disobeying its guidance. To set one's destination via OnStar, the driver has to press the blue OnStar button, which connects to a real, live OnStar representative (GM recently announced a partnership with MapQuest to enable drivers to send routes directly from a computer to the car, cutting out this step, but we like the human touch).
Our Saturn Aura Green Line was equipped with GM's OnStar navigation service.
Being immediately connected to the OnStar rep, we told her that we needed to get to Tehama Street, a small, back alley near CNET's headquarters in San Francisco. This is where the first of our journey's problems began. According to the nice lady, OnStar was experiencing technical difficulties due to a disruption to its cellular network coverage. As such, the system was unable to send out the text data that we would need for our journey. (Interestingly, we experienced a similar outage the last time that we tried to use the service in our review of the 2007 Chevy HHR in June).
The OnStar rep told us that this kind of outage happened from time to time, and that there was a workaround: she would read out a list of the turn-by-turn directions, which we could record and play back to ourselves throughout the journey. We could activate playback by pressing the phone button and saying "Adviser playback." This would then give us the option of hearing the list of directions either from the start or from our last position. It sounded like a reasonable alternative--unless we took a wrong turn, in which case all subsequent directions would be wrong, and we would have to start the process over again by calling in to OnStar for new directions.
We set out north on St Joseph's Drive but soon lost our way.
Steeled with optimism, we resolved to give it a go. Starting out from St Joseph's Drive (see map) we were told by the recorded voice to "continue north to Geary Boulevard and turn right." We pulled off, drove north on St Joseph's, came to a T-junction, and turned right at what we thought must be Geary Boulevard. Alas, it was not. We had found ourselves on O'Farrell Street, and with no means of recalculating the route, we were left to our own devices to find our way to the destination. Rather than call back, we opened the glove box and pulled out a map.
In the cabin
The interior of the 2007 Saturn Aura hybrid is fitting for a car that promotes itself as "the lowest priced hybrid on the market." In contrast to other hybrids, the Aura's cabin is conspicuously low tech with very few obvious gadgets to play with. Interior materials are plain but tasteful: beneath the black plastic cowl, the Aura features a strip of metallic, matte plastic trim, which brings some welcome brightness to the dash. As we found in the gasoline-only Aura, fit and finish are less pleasing to the eye, and the misalignment between the door panels and the dash sill in our test car was particularly noticeable.
As we have observed in the past, there is more to GM's factory-installed stereos than meets the eye. We found the same with the Aura Hybrid. While the car's standard (and only available) stereo looks like it might struggle to read compact discs, it is in fact a surprisingly sophisticated digital audio player with the ability to play and index MP3 and WMA discs. Despite its simple dot-matrix display, the Aura's stereo shows full ID3 tag information for folder, artist, and song title with more than 20 characters visible at one time. Moreover, when playing compressed-audio-format discs, a soft button enables drivers to index all the songs on a disc by sorting the ID3 tag information into an alphabetized list for albums and artists. With the five-minute sort process complete, drivers have a very intuitive and easy-to-use means of navigating dozens of songs on their homemade discs.
The Aura Green Line's standard stereo comes with a sophisticated ID3 tag sorting feature.
Being a standard GM rig, the Aura Hybrid's stereo also comes with a generic auxiliary-input jack to enable drivers to connect iPods and other portable MP3 players when on the road. On the downside, there is no means of upgrading the Aura's factory-installed audio capabilities, and the car comes without any option for satellite radio--a curious omission, seeing as we've seen XM in many other GM models with the same basic stereo infrastructure. With its six speakers, the Aura Green Line's audio system sounds adequate at low-to-mid volume, but starts to distort at higher volumes, particularly at the low end of the acoustic range.
Aside from the mirror-mounted OnStar interface detailed above, the only other notable tech features of the Aura Hybrid's cabin are its three hybrid-related instrument gauges. On the right-hand side of the instrument cluster, the assist/charge meter indicates the status of the battery, and whether it is being used to assist the engine (a swing of the needle upwards), whether it is being charged up by the regenerative braking system (downward swing) or whether there is no engine-battery exchange. On the left of the instrument cluster, the Aura's Autostop gauge indicates when the car's gasoline engine is cut during idling. Finally, a green backlit ECO fuel economy indicator illumines when the car is meeting or exceeding its average EPA fuel economy. For more details on these systems, see the Under the Hood section below.
The charge/assist gauge shows drivers the status of the NiMH battery pack.
As with the 2007 Saturn Vue Green Line, the Aura Green Line's air-conditioning system has a hybrid setting that allows it to be powered either from the battery or directly from the engine. With the A/C set to a temperature of 65 degrees or above, the system can be run on electric only, enabling the Autostop function to kick in when the car is idling. With the air conditioning set to 60 degrees, however, the A/C motor requires additional propulsion from the engine, preventing the Autostop function from activating.
Under the hood
Saturn's cut-price hybrid relies on cut-price technology. The Aura Green Line does have an electric motor, powered by its onboard nickel metal hydride (NiMH) battery pack, but as this is a "mild" rather than "full" hybrid, the car cannot be driven in elecric-only mode like some "full" hybrids. As with the Vue Green Line, the Aura Green Line relies on a system called Belt Alternator Starter (BAS), which replaces the car's alternator with an electric motor. This motor can be used either to assist the 2.4-liter gasoline engine when accelerating from standing and with increased load demand, or to charge the battery by turning the car's braking and deceleration into electricity.
The BAS system is also able to shut off the engine for up to 2 minutes during idling (Autostop) and to cut off the fuel supply during deceleration. All electrical systems in the Aura Green Line, including the air-conditioning and stereo, run on a 48-volt system connected directly to the battery pack, and can therefore still be operated during the Autostop mode.
The Autostop function cuts the car's engine during idling for two minutes.
In practice, the Aura Green Line feels underpowered for its size, even with the electric boost from the battery. Flooring the gas pedal on the freeway results in a bleat from the engine and some movement in the charge/assist gauge, but very little in the way of throttle response. On the positive side, the Aura Green Line's regenerative braking system is much less intrusive and provides a far more linear braking experience than those in the Mercury Mariner and Ford Escape hybrids.
Around the city, the Aura Green Line feels soft and flaccid in cornering, demonstrating predictable understeer, while on the freeway, it cruises along comfortably provided it is not required to perform any sudden bursts of acceleration. In freeway driving we also noticed a commendable level of cabin damping, with very little road or wind noise getting in. Despite its entry-level technology, the BAS hybrid system does offer significantly improved fuel economy over the gasoline-only Aura. In our 250 miles of driving, we observed an average fuel economy of 26 mpg: significantly better than the 20 mpg that we observed in the Aura XR, and in line with the EPA's updated estimates for the car of 24 mpg city/32 highway.
Our 2007 Saturn Aura Green Line test car came with a base price of $22,045. To this we added the only available factory option in the form of the $375 Preferred Package, which gave us power-adjustable seats, steering wheel audio controls, and folding power outside mirrors. Including a $650 destination fee, the final sticker price of our test car was $23,070, making it cheaper by some margin than the Honda Civic Hybrid, particularly with the Aura's $1,300 Federal tax credit. The Saturn Aura Green Line generally fulfills its mission of being a stripped-down, entry-level hybrid. Those looking for LCDs showing the intricate workings of complex hybrid systems should keep driving to the Toyota dealer: those looking for a no frills sedan that gets more than 25 mpg for less than $25,000 should consider the Aura Green Line.