One of the more enjoyable things to do in this business is having the opportunity to see new products months before they will be introduced to the public. This week we had the chance to preview and drive the new Saturn Vue Green Line. The new Vue will be the first of several ''value'' hybrid vehicles GM will introduce over the next few years.
GM has already released a ''mild hybrid'' in the Silverado pickup. The Silverado adds a 14 kw electric motor/generator sandwiched between the engine and transmission to add a start/stop capability to engine. The generator feature can even be used at jobsites to provide 115V AC power. GM claims up to 10% fuel savings with this system. But most people expect more fuel savings from a hybrid.
The new Saturn is significant in that the cost of the hybrid system will come it at under $2,000 over the cost of a standard Vue. This makes this GM hybrid system the least expensive in the industry by far. The cost savings was achieved primarily in two ways. One, by designing a hybrid drive that could be added on to an existing powertrain and secondly, by limiting the electric drive system voltage to 36 volts. The Vue Green Line starts with the proven Ecotec 2.4 liter 4 cylinder engine mated to a Hydra-Matic 4 speed transmission. The electric drive features a motor/generator that drives the Ecotec engine through a patented belt drive system. The belt drive is unique in that it is able to both transmit and absorb power without an excessively tight tension. This is important to reduce wear on the both the electric motor/generator and the gasoline engine. Because of the relatively standard engine/transmission used, the hybrid operates and feels very similar to the regular Vue while obtaining 20% fuel savings. The most noticeable difference is when at a stop, the Ecotec engine shuts down, leaving a surprising silence to the first time hybrid pilot. The tachometer pointer indicates the ''Auto Stop'' position. Another gauge informs the driver whether the 36 volt hybrid battery is supplying power or is being charged (regen) and an ''ECO'' light illuminates whenever the EPA mileage figure is being exceeded. This is the extent of the changes the driver sees. The lack of fancy electronic graphic indicators helps keep the costs down.
To achieve the impressive fuel savings, GM uses several strategies. First, the engine is shut down when the Vue is stopped. The engine restarts quietly once the brake pedal is released. Whenever the driver lifts their foot off the accelerator, like coasting down a hill, the fuel is shut off to the engine. The electric motor is used smooth out the transitions that would otherwise be felt by the driver. Variable valve timing is also used to achieve maximum efficiency of the gasoline engine. Again, the electric motor helps smooth out transitions. Regenerative braking is used in conjunction with the four wheel disk brakes to slow the Vue and recharge the battery. The system also looks for opportune times to charge the battery without harming fuel efficiency.
How is the hybrid Vue to drive? Thanks to the torque of the electric motor, off-the-line performance is very good, in fact the zero to sixty time beats the standard Vue by a full second. Don't let anyone tell you all hybrids are slow! Acceleration, cruising and braking feel identical to a regular car. We reported in our road test of the Honda Civic hybrid, click here for the article, that during braking, there was a detectable transition from the point where the regenerative braking turned off and the driver had to press slightly harder on the brake pedal to maintain the same braking load. Well, I could look right at the regen indicator on the Vue and could not feel when the regen was cut off. Very nice! GM estimates the Vue will achieve EPA mileage estimates of 27 mpg city and 32 highway. With the current controversy surrounding EPA figures and hybrids, GM hired an independent company to test the Vue Green Line under ''real world'' conditions. The Vue Green Line achieved 29.7 mpg compared to a standard Vue's 25.0 mpg over the same test route. The testing was done with the A/C on and driving 5 mph over the posted limit on real roads in normal traffic including full-throttle acceleration when entering freeways. GM has done their homework on hybrid systems and is offering a very nice vehicle at a reasonable price. Look for the 2007 Vue Green Line at Saturn dealers late this summer. The MSRP will be right around $23,000. Hopefully, Saturn dealers will stick with their ''one price'' strategy and not get too greedy, as I am sure the initial demand will be great.
More information and a ''driving demo'' can be found at www.saturn.com
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