Lexus GS 450h Sport Sedan Remains the Only Hybrid in Its Segment
The Lexus GS 450h enters its third model year as still the only hybrid-powered luxury sport sedan in its segment. With its advanced technology, high performance and indulgent luxury, the rear-wheel-drive 2008 GS 450h is the premium model in the GS series.Engine/Transmission/Drivetrain/Performance
Based on the new-generation GS platform and featuring Lexus Hybrid Drive technology, the GS 450h offers V8-like performance with greater fuel efficiency. In addition to boosting performance and fuel efficiency while lowering emissions, Lexus Hybrid Drive technology also further accentuates the brand's renowned smooth, quiet operation.
A full hybrid, the GS 450h is capable of operating in gas-only or electric-only modes, or a combination of the two. With its unique transmission, the GS 450h was the first hybrid vehicle to enable the electric drive motor to contribute to highway performance, not just slow-speed driving. Other manufacturers are now adopting 'dual mode' transmissions for their hybrid vehicles.
The GS 450h model's version of the Lexus Hybrid Drive powertrain combines a powerful 3.5-liter V6 engine with a compact, permanent magnet electric motor - all driving the rear wheels. The hybrid powertrain collectively produces 340 horsepower and can effortlessly accelerate the GS 450h from zero-to-60 mph in just 5.2 seconds.
Just as impressive as the GS 450h's acceleration from a stop is how quickly and powerfully torque is delivered during mid-range acceleration. The hybrid system's electric-drive motor delivers maximum torque immediately upon demand. This unique power-delivery characteristic is most noticeable, and most useful, during 30-to-50 mph passing and in traffic-merging maneuvers. The GS 450h returns EPA-estimated fuel economy of 22 mpg city/25 mpg highway/23 mpg combined and is certified as a Super-Low Emissions Vehicle II (SÚLEV II).
One of a new generation of Lexus engines, the gasoline V6 uses an Electronic Throttle Control System with intelligence (ETCS-i) and a dual fuel-injection system that combines the benefits of direct injection with those of port injection. Dual Variable Valve Timing with intelligence (VVT-i) operates on the intake and exhaust valves to further enhance power and torque across a broad engine speed range.
The GS 450h hybrid powertrain uses two motor-generators, MG1 and MG2 (the drive motor). Each performs specific functions and can operate as both a motor and a generator, although MG1 is used as a starter motor and provides no motive force. The engine-driven generator (MG1) can charge the battery pack or provide additional power to MG2 as needed.
A 288-volt DC Nickel Metal Hydride (Ni-MH) battery pack is installed behind the rear seat area. The battery's power is directed through a 'boost converter' that can efficiently raise voltage to a maximum 650V DC. An inverter changes this to AC, providing its elevated power to the 147-kW electric motor, which turns as high as 14,400 rpm. A 12-volt auxiliary battery powers various vehicle systems, including audio and navigation. (posted on conceptcarz.com)
Engine : 3.5 L., 6-cylinder
Power: 292 hp
Torque: 267 ft-lbs
Power from the gas engine and electric drive motor (MG2) is distributed to the rear drive wheels via a planetary gear-type Electronically controlled Continuously Variable Transmission (ECVT). This special transmission, which eliminates specific gear ratios, features a two-speed torque-multiplication device that allows drivers to select from among three driving modes: power, normal and snow. 'Normal' provides the smoothest operation and is ideal for city or suburban driving; 'Power' sharpens accelerator pedal response and 'Snow' mode softens accelerator pedal response making it easier to travel on slippery road surfaces.
The ECVT consists of a motor generator, motive power-dividing mechanism, two-stage motor-reduction device, electrically powered oil pump and hydraulic control system. The two-stage torque-multiplication device varies the gear ratio in two stages by controlling a planetary gear and two wet brakes, similar to the way a conventional automatic transmission operates.
This configuration allows the electric drive motor to operate in high or low ranges, with seamless transitions between the two. MG2 can therefore contribute power not just for acceleration, but at higher cruising speeds as well.
The GS 450h is driven solely by its electric motor when starting, traveling slowly, and during low-load driving, the resulting super-quite operation enhancing the luxury experience. A regenerative braking system further boosts system efficiency. When the vehicle is coasting or the brakes are applied, the electric motors function as generators, capturing kinetic energy that would normally be lost as heat through the brakes and transforming it into useable electricity to recharge the batteries.Chassis/Body/Suspension/Tires/Brakes
The GS 450h matches its powerful acceleration with responsive handling while maintaining the ultra-comfortable ride that is synonymous with the Lexus brand. Instead of attempting to mask noise, the engineers designed fans and motors to significantly reduce cabin-noise intrusion. Fluid-filled front-engine mounts, additional sound-absorbing asphalt sheets behind the instrument panel, and a new sound-absorbing windshield further enhance the quiet ride that redefines the term 'Lexus-like.'
Double-wishbone front and multilink rear suspension systems endow the GS 450h with engaging handling performance. Like the V8-powered GS 460 model, the GS 450h is equipped as standard with Adaptive Variable Suspension (AVS), a driver-selectable shock absorber damping system.
The standard 18 x 8-inch aluminum alloy wheels have a finish that is unique to the GS 450h and are equipped with 245/40R18 Z-rated summer performance tires; all-season run-flat tires are available. An optional Active Power Stabilizer system helps to further reduce body sway during cornering. The system uses an Electronic Control Únit (ECÚ) to calculate the force needed to counter excess body sway, which is then applied to the stabilizer bars by front and rear electric-powered actuators.
The GS 450h is equipped with the brand's highest level of dynamic handling technology: the Vehicle Dynamics Integrated Management (VDIM) system that goes beyond the capability of other stability and traction-control systems. VDIM is designed to anticipate the onset of a vehicle slide while cornering and then help to automatically correct the situation with a combination of braking, throttle and steering control in a way that is essentially transparent to the driver. VDIM integrates Electric Power Steering (EPS), Variable Gear Ratio Steering (VGRS), Antilock Braking System (ABS), Electronic Brake-force Distribution (EBD), Brake Assist (BA), Vehicle Stability Control (VSC), Electronically Controlled Brakes (ECB), and Traction Control (TRAC).Safety/Security Features
All Lexus GS models implement a wide array of advanced safety systems. The Supplemental Restraint System (SRS) includes variable-force front airbags for both the driver and front passenger. Sensors determine the severity of an impact and in turn the airbag deployment force, helping to provide an appropriate level of occupant restraint. The GS features standard seat-mounted side airbags for the front seats, knee airbags for the driver and front passenger, and front and rear side-curtain airbags.
The optional Pre-Collision System (PCS) can help the driver to avoid an accident. A millimeter-wave radar sensor helps detect obstacles in front of the car, while vehicle speed, steering-angle and yaw-rate inputs help to determine whether a collision is unavoidable. In such a situation, PCS switches the AVS to sport mode for optimal chassis response, preemptively retracts front seat belts, and pre-initializes Brake Assist so that increased braking will be applied the instant the driver depresses the pedal. The active-braking feature will automatically apply the brakes up to a deceleration rate of 0.3 G's if the driver fails to react to system warnings.
The Adaptive Front-lighting System (AFS) helps illuminate a curve as the driver steers into it. Intuitive Park Assist (IPA) uses ultrasonic sensors to detect the presence of objects close by and warn the driver of their proximity.Source - Lexus
Lexus GS Sedans Offer Customers Four Performance Model Choices for 2009
The 2009 Lexus GS luxury sport sedan model line includes the V6-powered GS 350 and the GS 350 all-wheel drive (AWD), the V8-powered GS 460, and the only gasoline electric hybrid model in the segment, the GS 450h.Engine/Transmission/Drivetrain/Performance
Optimized for low internal friction, the GS 350's 3.5-liter V6 engine produces 303 horsepower at 6,200 rpm and 274 lb.-ft. of peak torque at 3,600 rpm. A direct fuel-injection system provides much finer fuel-mixture control to improve both power and fuel efficiency. Dual Variable Valve Timing with intelligence (VVT-i) acts on both intake and exhaust valves to further enhance performance through a wide rpm range. A smooth-shifting six-speed transmission allows manual shifting when desired.
The GS 460's V8 produces 342 horsepower at 6,400 rpm and 339 lb.-ft. of peak torque at 4,100 rpm. The GS 460, like the GS 350, meets the EPA's Últra Low Emission Vehicle (ÚLEV-II) certification. Lexus has been setting standards for powertrain smoothness since its inception, and the GS 460's V8 and eight-speed automatic transmission continue that tradition. The transmission, as the six-speed automatic in the GS 350 models, allows manual shifting for a more engaging driving experience, and to maximize performance in certain driving situations. The GS 460 can accelerate from zero to 60 mph in 5.4 seconds, the GS 350 in 5.7 (5.8 for AWD).
The Lexus GS combines proven chassis systems with advanced dynamic handling technology to provide both agile handling and the Lexus trademark smooth ride. The double-wishbone front suspension and multilink rear suspension virtually eliminate unwanted wheel-angle changes during suspension movement. The result is a natural, confident feel that's also spirited. A 34.1-ft. turning circle (35.4 ft. for GS 350 AWD) is comparable to that of smaller cars and helps make the GS highly maneuverable.
In all GS models, Brake Assist (BA), Electronic Brake-force Distribution (EBD) and the Anti-lock Braking System (ABS) help form a powerful safety front. EBD optimizes brake pressure at each wheel to help minimize body dive or sway during hard braking and cornering. Brake Assist is designed to determine if the driver is attempting emergency braking, and, if the driver has not stepped firmly enough on the brake pedal to activate the ABS, it will apply maximum braking force until pedal pressure is released.
Aluminum-alloy 18-inch wheels are standard on the GS 460 and available for the rear-wheel-drive GS 350, which features standard 17-inch wheels. For maximum handling capability, the GS 350 comes standard with 225/50R17 W-rated summer tires. The all-season 17-inch run-flat tires that are standard on the GS 350 AWD model are available on the GS 350 RWD. The GS 460 is equipped with 245/40R18 Z-rated summer tires or available all-season run-flats.
The GS 350's available all-wheel-drive system helps to enhance handling in diverse driving conditions. A planetary-gear center differential and a wet-type multi-disc clutch control front-to-rear power distribution. The system normally sends 70 percent of available power to the rear wheels to provide the traditional performance advantages of a rear-drive car and will vary the torque-split ratio from 30:70 to 50:50 in response to driving conditions and driver input. The AWD system's electronic-control strategy takes inputs such as steering and throttle angle from driver activity combined with vehicle signals from wheel speed and yaw rate sensors.
An Adaptive Variable Suspension (AVS) system, standard on the GS 460 and available on the GS 350, provides four settings, including 'sport' for tighter, more precise control. AVS can automatically select appropriate suspension damping for driving conditions. The GS 460 also offers the advanced Active Power Stabilizer system that reduces body sway and enhances vehicle control during cornering. An Electronic Control Únit (ECÚ) calculates the force needed to counter excess body sway, which is then applied to the stabilizer bars by the front and rear actuators. The GS 350 models are equipped with Vehicle Stability Control (VSC) with traction control. The system can be disengaged with the 'Trac Off' switch when the situation warrants doing so.
In the GS 460, the Lexus Vehicle Dynamics Integrated Management (VDIM) system integrates and manages a host of handling technologies, including VSC. Combining input from a variety of sensors, VDIM is designed to anticipate the onset of a vehicle skid or slide and then help correct the situation with a combination of braking, throttle, and steering control. VDIM integration helps to provide precise management for the Electronically Controlled Brakes (ECB), Variable Gear Ratio Steering (VGRS), Electric Power Steering (EPS), Vehicle Stability Control (VSC), Anti-lock Braking System (ABS), Brake Assist (BA), Electronic Brake-force Distribution (EBD), and engine torque via the electronically controlled throttle.
Electric Power Steering (EPS) in the GS 460 provides precise electric power assist using a DC motor built into the steering gear housing. Also in the GS 460, Variable Gear Ratio Steering (VGRS) can vary the steering from 2.7 turns lock-to-lock for low-speed maneuverability to a slower 3.2 turns lock-to-lock for highway-speed stability. VGRS also provides differential steering control, which helps correct for a delay in steering response -- something that occurs in all vehicles -- to help enhance driving feel during lane changes and other transitional maneuvers.
The GS 460's Electronically Controlled Brakes (ECB) is a brake-by-wire system. ECB translates brake pedal pressure into electric signals that, via computer control, help provide precise and optimized braking. Electronic control provides quick brake response when needed, helping the GS 460's VDIM system to anticipate and help correct skids before they occur. The ECB system is backed by conventional hydraulic brake control in the unlikely event of electronic failure.Safety/Security Features
The Adaptive Front lighting System (AFS), standard on the GS 460 and optional for the GS 350, helps illuminate a curve as the driver steers into it. A Tire Pressure Monitoring system can detect a critical loss in pressure in one or more tires and alert the driver. The available Intuitive Park Assist (IPA) system uses ultrasonic sensors to detect objects close to the car's front and rear bumpers and alerts the driver accordingly. A steering-input sensor helps to better judge changes in distance to objects.
The Supplemental Restraint System (SRS) in the GS sedans includes variable-force front airbags for both the driver and front passenger. The GS features standard seat-mounted side airbags for the front seats, knee airbags for the driver and front passenger, and front and rear side-curtain airbags.
The rear back-up camera, available in conjunction with the optional navigation system, automatically projects an image of what its lens can detect behind the vehicle onto the navigation screen when the vehicle is in reverse gear.
The optional Pre-Collision System (PCS) in the GS models can help the driver avoid an accident. A millimeter-wave radar sensor helps detect obstacles in front of the car, while vehicle speed, steering angle and yaw-rate inputs help to determine whether a collision is unavoidable. In such a situation, PCS switches the Adaptive Variable-air Suspension to sport mode for optimal chassis response, preemptively retracts front seat belts, and pre-initializes Brake Assist so that increased braking will be applied the instant the driver depresses the pedal. The active-braking feature will automatically apply the brakes up to a deceleration rate of 0.3 g if the driver fails to react to system warnings.Luxury/Comfort/Convenience
The standard Regency leather-trimmed, heated, 10-way power front seats (perforated leather trim on GS 460) are comfortably contoured for support on long trips. Ventilated front seats are standard for the GS 460 and available for the GS 350. A power-tilt and telescopic steering wheel helps ensure a comfortable driving position. The standard dual-zone climate-control system filters the air, and a standard rear power sunshade adds to passenger comfort on warm days.
All four windows offer one-touch up-and-down operation with jam protection. Both electrochromic auto-dimming side mirrors are power-retractable and feature automatic tilt-down to aid in parking when reverse gear is selected. A power trunk closer provides an added convenience on this extremely well equipped car.
The standard Lexus audio system features an AM/FM/cassette stereo and a 6-disc, in-dash CD changer. The system plays through 10 premium speakers while an Automatic Sound Levelizer (ASL) maintains consistent sound levels at varying vehicle speeds. Luxury Options
Within the ultra-quiet Lexus GS interior, all styles of music come to life with the optional Mark Levinson® Premium Sound system. Featuring 11 channels of amplification with a total of 330 watts playing through 14 speakers, the system allows users to play both CDs and DVDs. DVD movies can be viewed on the color seven-inch touch screen when the parking brake is engaged.
The optional Lexus DVD Navigation System allows the driver to enter a destination by voice command. Visual support is greatly enhanced with a central screen featuring a high-resolution 800 x 480 pixel display in 32,000 colors. On-screen details are crisp and clean, and maps and roads are highlighted by 3-D shadow effects. Text display options include English, Spanish and French.
The DVD map database contains more than five million Points of Interest (POI). The database for Chicago, Detroit, Los Angeles, and New York includes a building footprint-display feature that can show graphic representations of buildings and structures to help the driver identify surroundings. System functions include multiple route calculations, route preview, simplified highway junction graphics, and a dual-map screen mode. Bluetooth® wireless technology integrates with the navigation system to allow the driver to make hands-free phone calls via its touch-screen control panel. Personal phone books can be transferred via Bluetooth, as well.Exterior Design
The current generation GS sedans introduced the brand's L-finesse design language. A 112.2-inch wheelbase, long hood, pulled-back cabin and short rear deck create a confident, powerful stance for the GS. A sloped, vertical grille surrounded by four independent headlamps visually connects the current GS sedans with the previous-generation models while signaling the brand's design progression. The lower valance features integrated fog lamps, and a low 0.27 coefficient of drag (Cd) helps to minimize wind noise and maximize highway fuel efficiency.Interior Design
Últra-premium wood, polished-metal accents and leather trim endow the GS interior with a lavish yet high-precision feel. Touch points convey quality and controls that respond fluidly. The customer can choose from among three interior leather color combinations: Light Gray leather with Dark Gray Bird's-eye maple wood trim, Cashmere leather with Golden Bird's-eye Maple wood trim, or Black leather with Red Walnut wood trim. Each combination includes a matching wood and leather-trim steering wheel and shift knob.
Lexus designers strive to keep controls simple and intuitive, avoiding needless complexity. The SmartAccess keyless entry and push-to-start ignition allow the driver to keep the access fob in a pocket or purse. Audio and climate-control systems are easy to understand and operate. The unique instrument panel lighting system relies on variable-transparency glass to minimize reflections from the gauge faces and to help optimize visibility in all lighting conditions. Warranty
All new Lexus vehicles come with a 48-month/50,000-mile basic limited warranty with roadside assistance for 48-months/unlimited miles. Powertrain and restraint system coverage is provided for 72 months/70,000 miles. Corrosion perforation protection is covered for 72 months, regardless of mileage.Source - Lexus