Sporty hybrid sedan
Bob Plunkett, Tue, 31 Oct 2006 08:00:00 PDT
WAIMEA, Hawaii -- On the Saddle Road, a warped ribbon of asphalt climbing the pass between cloud-covered volcanoes of Mauna Kea and Mauna Loa that crown the big island of Hawaii, we're pumping the juice to a super-quick sports sedan from Lexus.It's a new twist for a high-powered sportster as the Lexus GS 450h happens to be the world's first high performance hybrid electric vehicle (HEV).
The typical HEV, stocking a thrifty but conventional combustion engine which runs on gasoline plus an electric motor linked to a bank of rechargeable batteries, is designed to generate high fuel efficiency because it conserves gasoline by using supplemental energy supplied from the electric motor.
The typical high performance sports car contains a big and thirsty combustion engine with eight or more cylinders and delivers fast acceleration scores as well as gas-guzzling fuel consumption ratings.The GS 450h takes a different tack.
Yes, it has the high-tech HEV equipment on tap with a gas-electric powertrain and fuel economy numbers as frugal as a car with a four-cylinder engine.Yet it also produces quick performance times.It can charge from a stand-still start up to 60 mph in only 5.2 seconds, for instance, which makes this HEV the quickest production car ever built by Lexus.
But has Lexus forged the ultimate automotive oxymoron?Well, while the idea of installing HEV equipment and traits in a vehicle geared for high performance may sound incongruent, if not impossible, Lexus manages to pull the concept together in spectacular fashion and in the process deliver what surely ranks as the most sophisticated -- and complex -- luxury sports sedan on our planet.Actually, GS 450h consists of two disparate entities.
First, there's the bullet-shaped body and lavishly appointed passenger compartment of the mid-size GS luxury sports sedan, which emerged last year in a new generational treatment with a two-inch stretch in the wheelbase and an inch more in width on the rear wheel track.
Second, there's the high-voltage and high-torque Hybrid Synergy Drive (HSD) system developed by Lexus/Toyota to control all energy produced by on-board gas/electric engines and apply it directly to the rear wheels in infinitely variable measures through an electronically controlled continuously variable transmission (ECVT).
Summation of all powertrains in GS 450h is the equivalent of 340 hp (253 kW) and fuel economy numbers climbing to 25 mpg for city driving and 28 mpg on the road.By comparison, the more conventional GS 430 equipped with a gas-drinking 4.3-liter V8 and VVT-i (variable valve timing with intelligence) delivers 290 hp and fuel economy figures of 18 mpg city and 25 mpg highway.
For GS 450h, the HSD equipment is more extensive -- and far more powerful -- than that employed in any previous hybrid.It teams an efficient but strong Lexus 3.5-liter V6 gasoline-powered engine with a pair of high-torque electric motors -- one to turn the rear wheels and the second to work so many power accessories as well as crank up the gasoline engine and recharge a load of on-board batteries.
The V6 makes 292 hp at 6400 rpm and torque of 267 lb-ft at 4800 rpm.The first electric motor-generator (dubbed MG1) produces 134 kW (180 hp).The second electric motor-generator (MG2) turns the rear wheels and nets 147 kW (197 hp).Now, don't try to add up the horsepower ratings of the gas engine and the two electric motors to figure out the combined output because Lexus doesn't play it that way.
Technology clouds the performance numbers, as the GS 350h employs in the ECVT a dual-stage torque multiplication gear set that functions sort of like an electric supercharging system.Net effect: This thing is faster than you the driver expects, and it's also so quiet -- but what's absent here is the varoom-varoom sound effects common in conventional gas-fired performance cars.
And Lexus works to make the GS 450h look as conventional as the GS 430. Badging is discrete and visual differences between the GS 430 and GS 350h are slight.The body looks like it's poised for action in sporty low stance with a long hood and windswept windshield. Flanks are taut and the silhouette is curvaceous but so smooth it earns a coefficient of drag figure of only 0.27.
Sporty body elements are apparent -- a thick front valance with broad air inlet and square-cut foglamps, rocker extensions below side doors, the stubby tail treatment with a tall rear valance and twin exhaust pipes tipped in stainless steel.The cockpit orients toward the principal participant, the driver.
There are two bolstered bucket seats flanking a floor console, the steering wheel finished in wood and leather, and an instrument panel with 140-mph analog speedometer and tachometer plus an electronic digital odometer.Interestingly, the gauge cluster is covered by a lens of variable transparency capable of changing the lens diffusion in different light conditions to enhance viewing.
Centered on the dash is a large touch screen for controlling cabin features like climate and audio systems.Standard equipment includes leather upholstery and memory controls for seats with seat heaters, a keyless Smart Access system with push-button starter, in-dash CD changer, high intensity discharge (HID) headlights, rain-sensing wipers, a moonroof and a host of air bags like side curtains and front-seat knee shields.
Standard mechanical assets orient around the VDIM (Vehicle Dynamics Integrated Management) system which incorporates the variable gear ratio steering (VGRS), electronically controlled brakes (ECB), anti-lock brake system (ABS), vehicle stability control (VSC), electronic traction control (ETC), brake assist (BA), plus electronically controlled throttle system with intelligence (ECTS-i).
Options are limited to a Pre-Collision System packaged with Dynamic Radar Cruise Control (DRCC) system, all-season run-flat tires, a deluxe Mark Levinson audio system with 14 speakers and a DVD navigation system with rear backup camera, Bluetooth and voice activation.
Lexus marks the MSRP for a new GS 450h at $54,900.