Lexus introduced electrified technology in 2005, and with each successive generation, the benefits of this technology have incrementally improved. But while the focus on making cars cleaner and more efficient remains, the arrival of the new Lexus RX 500h demonstrates that we believe the time is right to offer an evolution of this technology that delivers a more exciting driving experience.
Detailed further below, the innovative hybrid powertrain at the heart of the RX 500h F Sport Performance consists of a new, turbocharged 2.4-litre petrol engine (see image below), front electric motor, six-speed automatic transmission, and a separate, high-output rear electric eAxle for precise all-wheel drive control.
RX 500h – new parallel hybrid architecture
The Lexus RX 500h is equipped with an all-new hybrid powertrain. Unlike anything Lexus has ever produced before, it offers forced induction and a new parallel hybrid architecture. This means that while the familiar principle of self-charging remains the same, the front electric motor is now sandwiched between a turbocharged 2.4-litre engine (known internally as T24A-FTS) and a new six-speed automatic transmission. Clutches on either side of the electric motor allow it to work in conjunction with, or independently from, the petrol engine. It is a layout that delivers strong power delivery and retains the EV driving capability that has always been a characteristic of our full hybrid electric system.
The RX 500h is the most powerful model in its five-generation history, with a total power output of 366bhp and 550Nm torque. This translates into 0-62mph acceleration in 6.2 seconds – the kind of performance you might expect of a 3.0-litre V6 engine but with superior economy. In that respect, 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 is employed instead of the eCVT system in other Lexus hybrid electric powertrains in order to better harness the higher levels of torque being produced by the turbo engine and motor. The transmission is programmed to capitalise on that torque and avoid frequent shifts, while offering the driver the option of instructing manual gear changes through 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 to use a bi-polar nickel-metal hydride battery (NiMH). This technology improves the battery’s load and unload capacity and allows 40% more cells to be accommodated, not to mention double the power output, within the same space as a traditional NiMH unit. The driver enjoys the benefit of stronger acceleration, while the battery is also quieter, thanks to refinement of its air-cooling system.
The RX 500h is also the first RX to adopt DIRECT4 all-wheel drive technology. This intelligent electronic control system constantly and seamlessly adjusts torque bias between the front and rear wheels to provide optimum grip and stability. Drive to the rear wheels is provided by the rear eAxle, which contains a separate electric motor and inverter to communicate a more connected feel between the road and the steering wheel.
Like the rest of the new RX range, the RX 500h is built on our GA-K platform, which gives the SUV a low centre of gravity, high body rigidity and a balanced chassis with good inertia characteristics. The performance focus continues with Dynamic Rear Steering, which automatically adjusts the angle of the rear wheels according to the car’s speed and direction – up to four degrees from the straight-ahead. 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 to keep the car stable.
The RX 500h model is also unique in being equipped with larger, more powerful front brakes. Compared to the ventilated 340mm diameter discs of its RX siblings, the RX 500h has 400mm diameter ventilated front discs. These are paired with high-performance six-piston aluminium calipers instead of the single-piston floating calipers of the other models. And as a distinguishing feature of this top-spec model, the calipers are notable for being painted black and bearing the Lexus logo. Finally, Adaptive Variable Suspension is specified, with fast-response, independent damping control applied at each corner.
The new hybrid experience explained by its engineer
The advanced powertrain is just one element in the equation. As chief engineer Takaaki Ohno explains, it works in harmony with a fine-tuned dynamic package that gives the driver a constant sense of connection, control comfort and confidence. He said: “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 further evolved the Lexus Driving Signature by thoroughly strengthening the vehicle fundamentals, as well as adopting [our] 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.”
All information is correct at the time of publishing