The benefits of electrification are not just about making cars cleaner and more fuel efficient. There are also real opportunities to deliver a more exciting driving experience, as Lexus’s radical new RX 500h F Sport Performance model proves
This exclusive member of the all-new RX family of large luxury SUVs is a new kind of hybrid electric model – one with a primary focus on performance. The hybrid powertrain is rich in innovation: a new, high-torque, turbocharged 2.4-litre engine, a six-speed automatic transmission and a separate rear electric eAxle enabling Lexus’s new DIRECT4 precision all-wheel drive control.
This advanced powertrain is just one element in the equation. It works in harmony with a fine-tuned dynamic package of chassis, steering, suspension and braking to give the driver a constant sense of connection, control comfort and confidence. These are the key elements in the brand-defining Lexus Driving Signature, delivered to great effect in the RX 500h.
Chief Engineer Takaaki Ohno explains: “Our goal with the RX 500h was to create a car that gives an exhilarating driving experience and generates a dialogue with the driver. To achieve this, we have further evolved the Lexus Driving Signature by thoroughly strengthening the vehicle fundamentals, as well as adopting Lexus’s new four-wheel drive force system, DIRECT4.
“The RX 500h delivers a powerful, direct, and responsive driving experience through a hybrid electric system with a new high output rear motor. The brakes offer excellent control and rigidity, and the car is equipped with Dynamic Rear Steering with a large steering angle that provides high manoeuvrability and a sense of security at high speeds. This further enhances interaction with the car and delivers a pleasant driving experience. Its addition to the RX range, along with fuel-efficient hybrid electric and plug-in hybrid electric models, provides a diverse line-up that can meet the needs and preferences of a wider range of customers.”
A new direction in hybrid electric technology
The new hybrid powertrain architecture is unlike anything Lexus has produced before. The essential self-charging principle is the same, but the front electric motor is positioned between the engine and the new automatic transmission, with a clutch on each side. This design gives strong power delivery while retaining the EV driving capability that’s characteristic of a Lexus full hybrid electric system. It is the most powerful RX yet, with total power output of 366bhp/273kW and 550Nm maximum torque. This translates into 0-62mph acceleration in 6.2 seconds. This is the kind of performance you might expect from a three-litre V6 engine, but with superior fuel economy – the RX 500h achieves 34 to 35.3mpg on the WLTP combined cycle.
A new, compact, six-speed automatic transmission has been introduced for the first time. It’s being used in preference to the eCVT system in other Lexus hybrid electric powertrains to better realise the potential of the high torque from the turbo engine and motor. It is engineered to avoid frequent shifts and offers the driver the option of manual operation using paddle controls on the steering wheel. When the driver presses the throttle, response is instant with a powerful, linear increase in speed.
The RX 500h is the first Lexus model to use a bi-polar nickel-metal hydride battery (NiMH). This technology reduces resistance so the battery has a higher load and unload capacity. It also allows the unit’s size to be optimised – 1.4 times the number of cells can be accommodated in the same space compared to the standard NiMH battery. These qualities enable twice the power to be achieved from a unit of the same size. The driver enjoys the benefit of stronger acceleration while the battery’s location beneath the car’s rear seat helps the low centre of gravity and avoids loss of cabin or load space. The battery is also quieter, thanks to refinement of its air-cooling system.
DIRECT4 all-wheel drive force control
The RX 500h is the first RX to adopt Lexus’s new DIRECT4, an intelligent electronic control system that instantaneously and seamlessly adjusts the front and rear drive torque to all four wheels to provide optimum grip and maintain stability. Drive to the rear wheels is provided by the rear eAxle with a separate electric motor and inverter. It makes for a more comfortable ride with better body control and a more rewarding experience for the driver, communicating a more connected feel between the road and the steering wheel.
Bespoke dynamic features
Like the rest of the new RX range, the RX 500h has the fundamental benefit of the Lexus GA-K platform, giving the car a low centre of gravity, high body rigidity and a balanced chassis with good inertia characteristics. Building on this, the car’s dynamic elements have been tuned and engineered with a performance focus. These include Dynamic Rear Steering which automatically adopts the best steering angle for the rear wheels, according to the car’s speed and direction. At low speeds, the wheels move counter to those at the front for nimble manoeuvring, while at high speeds they turn in line with the front axle, helping keep the car stable. The system gives the rear wheels turning angles of up to four degrees.
More powerful brakes are fitted – 400mm ventilated front discs with six-piston aluminium callipers that are opposed rather than floating (as on other new RX models), giving greater rigidity. With an enlarged pad surface area, they give linear, direct and stable stopping performance. They are also a distinctive feature for the model, being painted black and bearing the Lexus logo. Adaptive Variable Suspension is also provided, with fast-response, independent damping control applied at each wheel.
Performance styling
This is a car that stands out, with styling features added to the new RX’s “Next Chapter” design that express its performance character. These include dedicated split-spoke 21-inch alloy wheels, body colour wheel arch trims and sills, piano black details, aero profile bumpers, F Sport badging and an exclusive mesh pattern for the grille. Inside, the theme continues with the F Sport steering wheel, shift lever and scuff plates and an aluminium pedal set. The sports front seats are finished in leather with tactile Ultrasuede bolsters.
