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3 March 2009
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INTRODUCING THE LEXUS RX 450h KEY POINTS
The new Lexus RX 450h follows on from the 2005 launch of the ground-breaking RX 400h to introduce second-generation Lexus Hybrid Drive technology. In the RX 450h, Lexus marked the first successful dovetailing of high performance with the hybrid benefits of fuel economy and low emissions, revolutionising powertrain technology in the premium segment. The system has undergone significant development in the RX 450h. Unlike mild hybrids, which use supplementary electric motor power simply to boost the performance of the petrol engine, the RX 450h is a full hybrid, capable of operation in both petrol and electric modes alone, or in a combination of both. It delivers the energy-saving benefits of a series hybrid and the acceleration performance of a parallel hybrid system. LEXUS HYBRID DRIVE However, comprehensive enhancements to all the system’s components have dramatically improved efficiency, achieving a 10 per cent increase in engine power and a 28 per cent reduction in fuel consumption. The improvements to achieve improved performance, driveability, fuel economy, noise and emissions include:
Total power output is 295bhp (299 DIN hp), enabling a top speed of 124mph and 0 to 62mph acceleration in 7.8 seconds. Conversely, the RX 450h has the lowest fuel consumption of any premium crossover model with a combined cycle figure of 44.8mpg. CO2 emissions are also remarkably low at just 148g/km. Hybrid Drive System Configuration The front drive unit is a series/parallel hybrid system featuring a 3.5-litre V6 petrol engine, a powerful electric motor, a generator, a high performance battery, a power control unit and a power split device with a planetary gear set to combine and re-allocate power from the engine, electric motors and generator as driving conditions require. The rear unit provides four-wheel drive by means of a second electric motor and is mechanically independent of the front unit. The motor is activated and continuously adjusted by the Vehicle Dynamics Integrated Management (VDIM) system, working in conjunction with the power control unit. V6 Petrol Engine In an Atkinson cycle engine the valves close late, delaying compression. This creates a high expansion ratio for less compression, reducing intake and exhaust energy losses and converting combustion energy into engine power more effectively. As a result the exhaust temperature is lower than in conventional engines. EGR reintroduces cooled exhaust gas into the combustion chamber, further reducing the engine’s operating temperatures. Together these technologies minimise the need for any fuel enrichment to provide a cooling effect and protect the catalytic converter from overheating damage, thereby improving fuel economy and reducing emissions. The EHR system uses exhaust gas heat to warm the engine coolant at start-up. This reduces the time the engine needs to warm up, allowing it to be shut off earlier for longer electric motor-only operation, particularly in winter. As a result, the RX 450h achieves an increase of more than 30 per cent in cold weather fuel efficiency compared to the RX 400h. Power Control Unit Electric Motors Hybrid Transaxle An improved flywheel damper, with a two-stage, torque absorbing damper, absorbs torque fluctuations and also the shock of engine stop and start. This significantly reduces vibration and noise, notably in urban driving when the engine stops and starts most often. Artificial Intelligence AI-SHIFT control has been adopted for the first time on a hybrid vehicle. The system determines whether the vehicle is travelling up or downhill by comparing vehicle speed with accelerator pedal angle. The transmission then selects the appropriate shift range – from third to sixth – to maintain engine rpm at an optimum speed for either uphill acceleration or downhill engine braking. Sequential shift-matic control is also available, by selecting ‘S’ in the transmission shift gate. In this mode the driver can select any of six speeds to gain more responsive performance, or to add engine braking assistance. Three New Driving Modes Linked to an indicator in the speedometer, the new ECO mode provides a modified, non-linear throttle action and air conditioning control to support fuel-efficient driving. The relationship between accelerator pedal movement and system output is automatically controlled to reduce throttle response to aggressive driver inputs, improving fuel economy and promoting smoother driving. The air conditioning load on the engine is also reduced sharply under acceleration, further adding to fuel efficiency. Activated by means of the Multi-information switch on the steering wheel, EV mode allows the RX 450h to be driven under electric motor power alone. This driving mode is not available to drivers of mild hybrid vehicles; it requires a full hybrid technology such as Lexus Hybrid Drive. In EV mode the vehicle can be driven around town with minimal noise and zero emissions, with driving range determined by the level of battery charge. As the petrol engine is switched off, the EV drive mode contributes to a significant reduction in overall fuel consumption. SNOW mode, also selected with the Multi-information switch, helps modulate use of the accelerator pedal and improve vehicle stability when pulling away on snow or other slippery road surfaces. Pedal inputs are automatically adjusted to reduce driving torque and minimise wheelspin; should there be any wheelspin, the rear electric motor engages to improve traction. DRIVING DYNAMICS High-rigidity Bodyshell All-new Rear and Revised Front Suspension The front MacPherson struts gain new shock absorbers and revised geometry, springs and stabilisers. The diameter of the front anti-roll bar has been increased, improving cornering stability. The RX 400h’s strut-type rear suspension has been replaced with a new trailing arm, double wishbone configuration that features high-tensile pressed steel components that are lightweight but highly rigid. The system’s wider arm span and rigid trailing arm and carrier joints contribute to a high level of agility and stability, while careful attention to packaging, including locating the springs under the vehicle floor and low, angled shock absorber mountings, minimises suspension intrusion into the luggage floor. As a result the loadspace floor width has increased by 150mm. Electronically Controlled Air Suspension The system automatically maintains a level vehicle posture, regardless of how many people or what size load is on board. Four suspension heights are available, selected using a control switch by the driver’s seat: Normal, High (+30mm), Low (-20mm front, -5mm rear) and a Loading mode (-30mm), available only when the vehicle is stationary. For convenience, a second Loading mode switch is located on the side wall of the luggage compartment, and the function can still be used when the hybrid system is switched off. Normal mode is suitable for everyday driving. When travelling at motorway speeds, the system will automatically lower to a height equivalent to Low mode to improve aerodynamic stability and fuel efficiency. Active Stabiliser System The system uses variable twist-torque front and rear anti-roll bars to enhance body control and steering precision in high-performance driving, without compromising straight-line ride comfort. In straight-line driving the system is inactive, in line with the energy-saving objectives of Lexus Hybrid Drive. Motors located at the centre of each anti-roll bar are activated when the vehicle is cornering and apply twist-torque to both left and right sections of the bar. By applying the right degree of twist force independently to the front and rear anti-roll bars, the highly responsive system controls vehicle roll motion, reducing body roll angles to promote vehicle stability, superior cornering performance, passenger comfort and greater agility through improved steering response.. Electric Four-wheel Drive Electric Power Steering Electronic Brake Control (EBC) System The second-generation Electronic Brake Control system has an independent power supply and works with VDIM to give improved brake pedal feel and linearity, optimum four-wheel independent brakeforce distribution, braking assistance and maximised energy regeneration. Lexus Hybrid Drive provides all four wheels with regenerative braking during deceleration and braking, recovering kinetic energy that would normally be lost as heat, as electrical energy for storage in the system’s high-performance battery. EXTERIOR DESIGN The new RX is strongly influenced by the powerful and streamlined monoform architecture of Lexus’s LF-Xh concept crossover, bringing together the seemingly contradictory ideas of a ‘robust, muscular stance’ and ‘elegance and intelligence’. The new RX combines the road presence of a pioneering crossover with the most compact packaging possible. It is 35mm longer, 40mm wider, 10mm higher and has a wheelbase that is 25mm longer than its predecessor, but these increases have been kept to a minimum in order to preserve the car’s agility and town-friendly manoeuvrability. RX maintains its class-leading 5.7m turning radius. The latest interpretation of the classic Lexus front grille flows from the bonnet and fuses with the front bumper, combining with the L-finesse positioning of the headlights and grille to emphasise the ‘Resolute Look’ that is common to every Lexus. Interlocking trapezoidal forms flowing from the bumper to the front wheelarches emphasise the wide track and the vehicle’s powerful stance. Optional, highly sculptural LED headlamps add more power to the design. The RX 450h’s streamlined silhouette preserves the classic image of a crossover, while the clear axis of the shoulder and distinct crease along the C-pillar form a new architectural framework. The pronounced wheelarches flow seamlessly into both bumper and doors, and the vehicle’s taut rear corners are emphasised by the smooth integration of the bumper. Distinctive side window mouldings adopt the L-finesse arrowhead shape, following a subtly concave line across the A and C-pillars before extending at either end. The plated door base mouldings increase in thickness towards the rear of the vehicle, giving a sense of strength and lowered centre of gravity. Aerodynamic Multi-function Design Distinctive Design Features INTERIOR DESIGN Crossover Cockpit The overall height of the dashboard has been significantly reduced thanks to the introduction of the world’s slimmest centre console air vents. The space is divided into two distinct zones: an upper Display Zone, which combines an optional head-up display with an eight-inch colour LCD multi-display screen ideally positioned for at-a-glance viewing, and a lower Operation Zone, which gives access to controls such as the multi-information switch on the steering wheel and Remote Touch (see below). Remote Touch To make it easier to select an icon, the system automatically ‘pulls’ the cursor to an icon if it passes close to it. This makes the system fast and easy to use, minimising driver distraction time. Head-up Display Multi-information Switch and OLED Display Smart Entry and Start System Easy Exit and Entry Dual-speed Windows Seating The full-leather seats are more comfortable thanks to increased backrest height and width and cushion thickness and width. A new, optional electric cushion length adjustment is also introduced for the front seats, while new heaters provide heat at different temperatures across different parts of the seat. The rear seats maintain the proven 40:20:40 split-folding design, which offers more flexibility and practicality than the usual 60:40 format. The seats can be slid forwards and backwards to increase legroom or luggage capacity, and can also be reclined. Storage and Luggage Compartment Thanks to the adoption of the new double wishbone rear suspension, there is significantly less intrusion in the luggage compartment. The floor width has been increased by 150mm and overall volume has grown to 496 litres. New levers are mounted on the side wall of the load space to allow one-touch remote folding of the rear seats. Models with air suspension also have a side wall-mounted height adjustment switch, which lets the vehicle be lowered by 30mm to facilitate easier loading. Air Conditioning Fan and vent noise levels have been substantially reduced and a clean air filter prevents pollen and dust from entering the cabin. An exhaust gas-detecting recirculation function automatically switches between fresh and recirculated air modes to maintain good cabin air quality. Audio Systems Three systems are available. The entry-level system comprises a six-disc in-dash CD changer, steering wheel-mounted controls and nine speakers. DAB-ready, it provides USB and audio jack plug connections for fully controlled use of portable music players such as iPods, and Bluetooth mobile phone connectivity with an audio/video streaming function. A 12-speaker system is also available, with all the above features and the Lexus Navigation System. The new top-of-the-range 15-speaker Mark Levinson premium surround sound system allows RX owners to enjoy perfect home theatre 7.1-channel surround sound from selected CDs and DVDs. It also makes use of the navigation system’s hard disk drive (HDD) to provide a sound library facility, using compact Disc Data Base technology to transfer and store music files up to a 10GB capacity. Lexus Navigation System Parking Assist and Side Monitors The system uses Charged Coupled Device (CDD) cameras built into the passenger door mirror and the rear of the vehicle, which work in conjunction with the front and rear parking sensors to give a view of areas around the vehicle that are difficult to see from the driver’s seat. Real-time images are shown on either the central display (on models equipped with the Lexus Navigation System), or the interior rear-view mirror. For added security, the door mirror camera will continue to work even if the mirrors are folded back when negotiating a narrow space. SAFETY Passive Safety The new Crossover Cockpit design is ergonomically excellent and offers maximum instrument clarity, allowing drivers to relax and concentrate on the road. The new head-up display combines with a multi-information screen to keep all essential data within the driver’s field of view, and a multi-information switch that lets the driver monitor vehicle information while keeping both hands on the wheel. The RX 450h is equipped with 10 airbags, including knee airbags for driver and front seat passenger and full-length curtain shield airbags. The front passenger benefits from a dual-stage twin-chamber airbag that safely cradles the face like a baseball catcher’s glove. This design has won a ‘breakthrough technology award’ in the USA. Further protection is provided by active front seat headrests, which pop up and forwards in the event of a rear collision, closing the distance between the occupant and the headrest to minimise the risk of whiplash. Active Safety If PCS judges a collision to be highly possible, it will alert the driver and when he or she begins to brake, it will activate Pre-Crash Brake Assist. The Pre-Crash seatbelt is also activated under emergency braking, or if there is a risk of a loss of vehicle stability. Adaptive Cruise Control (ACC) works in tandem with PCS at speeds between 31 and 106mph (50 to 170km/h). ACC automatically maintains a selected distance from the vehicle in front, returning to the original cruising speed once the road ahead is clear. The new RX 450h also features a new Hill-start Assist Control (HAC). This briefly maintains brake pressure as the driver moves his or her foot from the brake to the accelerator, to prevent the vehicle from rolling backwards on an incline. Because the system requires less accelerator input, it reduces wheelspin and gives smoother pulling-away performance. Lexus’s Vehicle Dynamics Integrated Management (VDIM) processes vehicle status data from sensors located through the car, integrating the function of the ABS, traction control (TRC), Vehicle Stability Control (VSC) and Electronically Controlled Brakes (ECB) with the Electric Power Steering, and also co-ordinating control of the Lexus Hybrid Drive and electric four-wheel drive systems. Through its integrated control of all the elements relating to vehicle movement, including motor torque, brakes and steering, VDIM not only optimises activation of braking, stability and traction control systems, it further improves the vehicle’s overall dynamic performance. For example, when braking on a surface with unequal grip, VDIM automatically counteracts the different left and right-side braking forces to maintain straight-line braking. In the event of under or oversteer, VDIM seamlessly combines engine output and braking control to stabilise the vehicle. Moreover, via the EPS actuator, VDIM will augment VSC operation by providing steering assistance to reduce torque steer under braking on surfaces with varying grip. It will also introduce steering torque assistance in under and oversteer conditions to help the driver make the appropriate steering input to maintain vehicle stability. ENDS This and further Lexus information and pictures can be downloaded from the Lexus media website on: http://www.lexusgb-press.co.uk or through www.newspress.co.uk For further information contact one of the following: Ref: 090303N 57127/020309
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