New Lexus RX 450h

The new Lexus RX 450h introduces second generation Lexus Hybrid Drive technology, following on from the 2005 launch of the original, ground-breaking RX 400h. This new, full hybrid SUV Lexus Hybrid Drive takes the RX range into its third generation as the world’s best selling luxury SUV.

The new model perfectly expresses the kaizen and forward-thinking inherent in Lexus’s L-finesse design philosophy. While many rival manufacturers are yet to produce a first generation hybrid, Lexus has drawn on more than a decade of experience in full hybrid powertrain technology to bring about improvements in every aspect of the vehicle’s Lexus Hybrid Drive system.

As a result, the RX 450h’s real-world efficiency has been significantly improved, with a 10 per cent increase in engine power, a 28 per cent reduction in combined cycle fuel consumption, a 30 per cent improvement in cold weather fuel efficiency and an unparalleled reduction in CO2 emissions.

Lexus Hybrid Drive

Unlike mild hybrids, which use supplementary electric motor power simply to boost the performance of the petrol engine, the RX 450h is a full series/parallel hybrid, capable of operation in both petrol and electric modes alone, or in a combination of both. It combines the fuel efficiency and reduced emissions benefits of a series hybrid with the acceleration benefits of a parallel hybrid.

It shares the RX 400h’s drivetrain configuration of a series/parallel hybrid system, employing a highly efficient V6 petrol engine and two powerful electric motors working in tandem to provide an ‘intelligent’ four-wheel drive capability.

Total power output is 295bhp (299 DIN hp), enabling a top speed of 124mph and nought to 62mph acceleration in 7.8 seconds. Conversely, the RX 450h has the lowest fuel consumption of any premium SUV model with a combined cycle figure of 44.8mpg. CO2 emissions are also remarkably low at just 148g/km. The 3.5-litre DOHC petrol engine is based on that used in the RX 350, but has been adapted specifically for use in the hybrid powertrain. It produces a maximum 246bhp (249 DIN hp) at 6,000rpm and 317Nm of torque at 4,800rpm, and features three Lexus hybrid ‘firsts’ to optimise the fuel efficiency: Atkinson Cycle, Cooled Exhaust Gas Recirculation (EGR) and Exhaust Heat Recovery (EHR).

The hybrid drive system benefits from refinements in drivability through expanded electric motor maximum torque bands and a new AI-SHIFT transmission control strategy to optimise engine efficiency.

Three new driving modes, ECO, EV and SNOW, further improve the system’s fuel efficiency and driving performance. EV mode, available only with the full hybrid capability of Lexus Hybrid Drive and not available to drivers of mild hybrid vehicles, allows the car to be driven under electric power alone, with minimal noise and zero CO2 and NOx exhaust emissions.

Driving Dynamics

The new RX 450h was designed specifically to meet the dynamic handling requirements of the European market and sets new standards for handling and driving enjoyment in the SUV segment. It delivers the high-speed cruising comfort and composure of a premium saloon, responsive handling and agility on winding roads and, through its electric four-wheel drive system, stable and tenacious performance.

A new double wishbone rear suspension configuration replaces the strut-type system used in the RX 400h. Allied to an increase in wheelbase length and track width, this enhances body roll and pitch control. The front suspension has also been extensively re-engineered, with new shock absorbers, optimised springs, anti-roll bar and component geometry.

Dynamic ability is further improved by an active stabiliser system, reducing body roll by almost 40 per cent in 0.5G corners. Electronically Controlled Air Suspension gives the driver a choice of four vehicle height settings over a 60mm range and automatically lowers when travelling at speed to optimise aerodynamic performance, stability and fuel economy.

Design

The new RX 450h combines the road presence of a premium SUV with the most compact packaging possible. It is 15mm 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 circle. The reduction of panel gaps and the management of airflow under the vehicle combine with several multi-function aerodynamic elements to minimise turbulence and give the RX 450h a class leading drag coefficient (Cd) of 0.32.

Inside the vehicle, the new advanced cockpit design showcases numerous advanced features. The design divides the dashboard into two distinct zones: an upper Display Zone, which includes the Head-Up Display and an eight-inch LCD multi-display screen, and a lower Operation Zone, which contains system controls such as the steering wheel-mounted multi-information switch and Remote Touch control.

Technology
The RX 450h marks the debut of the innovative Remote Touch control, an integral part of the new Lexus Navigation System. It operates on the same basic principles as a computer mouse, with tactile force feedback when operated. It is quick and intuitive to use in conjunction with icons presented on the central multi-display screen to access and adjust the vehicle’s audio, navigation, ventilation, phone and set-up systems.

The new Head-Up Display presents key driving data in the driver’s line of sight at the base of the windscreen. The white display is designed for perfect clarity in all conditions. The information presented includes vehicle speed, turn-by-turn navigation instructions, audio information and Adaptive Cruise Control and Pre-Crash Safety system status.

A multi-information toggle switch mounted on the steering wheel lets the driver activate and customise numerous vehicle functions and information systems without taking a hand off the wheel. The control is linked to a new white OLED multi-information display set within the driver’s instrument binnacle.

Other key features of the new RX 450h range include a Smart Entry and Start system, automatic moving of the driver’s seat and steering wheel for easy entry and exit, dual-speed power windows and a new, more efficient dual-zone climate control system.

Lexus builds on its established high standards in in-car hi-fi with three new powerful audio systems for the RX 450h. These include a top-of-the-range 15-speaker Mark Levinson® Premium Surround System that gives perfect 7.1-channel surround sound. Using the navigation system’s Hard Disc Drive, the audio system has a ‘sound library’ facility that uses Compact Disc Data Base technology to transfer and store up to 10Gb of music files.

The new navigation system, accessed by the Remote Touch control, has a 40Gb HDD capacity, making it one of the fastest and most accurate systems on the market. It covers the whole of Europe and includes traffic information infrastructure and 3D mapping.

Safety

The RX 450h’s Pre-Crash Safety (PCS) system sets a new benchmark for anticipatory, preventive safety. Operating at speeds above 3mph, it uses a millimetre-wave radar sensor to detect objects ahead, determines the collision risk and helps the driver reduce the chances of an accident happening.

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 to supplement the driver’s braking effort. If the driver does not brake and a collision is inevitable, the Pre-Crash Brake will automatically apply the brakes to reduce impact speed. 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.

Lexus’s unique Vehicle Dynamics Integrated Management (VDIM) system 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.