Saturn Vue 2 Mode Hybrid CUV earns high fuel economy scores
Bob Plunkett, Thu, 4 Dec 2008 08:00:00 PDT
BEAR MOUNTAIN, N.Y. -- A special edition of the Vue, Saturn's car-like crossover utility vehicle (CUV) for the compact class, effortlessly tackles acute curves on a steep grade as New York Route 17 runs up Bear Mountain out of the Hudson River Valley.
Well, the automaker proclaims that this 2009 Vue is the world's most fuel-efficient V6-equipped CUV. Its fuel economy estimates top 27 mpg and its reduced emissions score earns the classification of an advanced technology partial zero emission vehicle (ATPZEV).
To achieve such bragging rights, the Vue powering up Bear Mountain has to be a hybrid electric vehicle (HEV).
However, this particular HEV goes further than the 2009 Vue Hybrid, which employs a 2.4-liter in-line-four engine worth 164 hp and an electric motor/generator plus a control unit which shuts off the gas-drinking engine when the vehicle stops or converts vehicle kinetic energy to electrical energy through regenerative braking to charge the hybrid battery pack.
It seems this new HEV Vue stocks a special dual-mode hybrid propulsion system developed to improve fuel economy scores.
Thus, the tag for this version of Saturn's CUV is the Vue 2 Mode Hybrid.
The plant displaces 3.6 liters and contains dual overhead cams and variable valve timing (VVT) with direct injection technology applied to shoot the fuel directly into each of six combustion chambers and produce higher compression ratios. This device also pares cold-start hydrocarbon emissions by as much as 25 percent.
Vue's V6 knocks out 255 hp at 5800 rpm and keen torque up to 252 lb-ft at 4000 rpm.
In addition to the V6 gas-drinking engine, the Vue 2-Mode Hybrid carries supplemental power sources.
These electric motors are packaged with three planetary gearsets and four hydraulic wet clutches as components of GM's new electrically variable transmission (EVT).
A sophisticated control unit -- dubbed the Hybrid Optimizing System (HOS) -- manages all energy produced by the on-board gas/electric engines and applies it directly to Vue's front wheels in infinitely variable measures, as well as providing four fixed-gear ratios so the operation mimics a conventional automatic transmission.
Power to run the two electric motors flows from a 300-volt nickel-metal hydride battery pack, the Energy Storage System (ESS) which is housed in Vue's cabin below the second-row bench seat. The ESS also stores energy produced during regenerative braking and may be charged by the V6 engine with one of the electric motors used as a generator.
At low speed the CUV can move forward or backward using an electric motor or the gas-fired V6 or a combination of the V6 and electric motor.
At highway speed Vue's second mode works with all six cylinders of the gasoline engine pumping when commanded.
Or an electric assist may be added to enhance the gas V6 for high-demand power situations, such as when towing a trailer rig or climbing a steep grade like Route 17 on Bear Mountain.
And when the HEV-CUV stops, the V6 engine shuts down, leaving only electric motors running.
The point of using all of this equipment on a CUV like Vue is to trim the powertrain's fuel consumption and reduce tailpipe emissions.
However, the front-end cost to add all of the hybrid equipment on a Vue V6 amounts to some $6,000.
Saturn sets the MSRP for a 2009 Vue 2 Mode Hybrid around $33,000, while the tag for a 2009 Vue XR with only the 3.6-liter V6 tallies to about $27,000.
Variances from convention with Vue 2 Mode Hybrid include the unique electric power steering (EPS) system, which consists of an electrically driven 12-volt variable-assist power steering rack.
It eliminates the conventional hydraulic apparatus along with the power losses of an engine-driven pneumatic pump, and also pares pounds.
The brake system consists of a big disc at every wheel and a four-wheel anti-lock brake system (ABS) for straight-line brake tracking, plus a traction control system (TCS), electronic stability control (ESC), rollover detection system (RDS), electronic trailer sway control (TSC) and a tire pressure monitoring system (TPMS).
And the HEV has that regenerative braking system to capture electricity generated through vehicle braking and decelerating to recharge the ESS so it never needs to be plugged in for recharging like an electric vehicle.
The HEV version of Vue looks virtually identical to a conventional Vue, save for strips of decals denoting "2 Mode" and "Hybrid" plus special fender and tailgate badges.
But there are subtle modifications to pare the body weight and improve aerodynamics, such the lowered ride height and special low rolling-resistance tires (P225/65R17) to boost fuel economy.
Added touches of chrome mark the Vue 2 Mode Hybrid like chrome-coated door handles, twin exhaust tips in chrome and chrome skid plates on front and rear fascia.
Two doors on each side provide access for passengers into the cabin, while a liftgate in back leads into the cargo compartment.
On the instrument panel, the customary tachometer has been replaced by an efficiency gauge which indicates when the vehicle achieves maximum fuel economy and operating mode -- electric-only, engine-only, or a combination.
Since the HEV remains completely silent when you turn the ignition key for start-up, the IP also includes a telltale lamp to indicate when this Vue is running.