Lexus-RX
The
Lexus RX is a crossover sport utility vehicle (SUV) sold since 1998 by Lexus, the luxury division of Toyota. Originally released in its home market of Japan in late 1997 as the
Toyota Harrier, exports began in early 1998 as Lexus RX. Three generations of the Lexus RX have been produced to date, the first being compact in size, and the latter two classified as mid-size. Both front- and four-wheel drive configurations have been used on the RX series, and several gasoline powertrain options, including V6 engines and hybrid systems, have been offered. In the Lexus model lineup, the RX sits below the larger GX and LX body-on-frame SUVs, and remains the marque's only crossover model. The RX name stands for Radiant Crossover.
It has also been labelled as "Recreation Cross Country" in some markets.
Introduced in 2009 as a 2010 model year vehicle, the RX 450h
(GLV10/GLV15) premiered alongside its non-hybrid counterpart, the RX
350. Manufacturer's specifications indicated largely identical outward
dimensions for the RX 450h with the RX 350.
The RX 450h was scheduled to go on sale in the U.S. in mid to late 2009,
with sales introductions for the RX 450h in Asia (including Japan) and
Europe in the same year. The RX 450h features an upgraded 3.5 L
2GR-FE V6 engine (shared with the RX 350) which produces 245 hp (183 kW) at 6000 rpm,
along with a new inverter which boosts total horsepower to 297 hp
(221 kW) (with the electric motors providing an added 22 hp (16 kW)).
The new inverter is 8 kg lighter, and more efficient. Up to three
electric motors are used in the hybrid system, including two dual motors
for the forward wheels (123 kW output), and a third for the rear wheels
on the AWD model (50 kW; engages when slippage is detected or the
throttle pressed firmly).
The RX 450h's V6 engine now runs on the Atkinson cycle for added efficiency.
Compared to the prior Otto cycle system, the Atkinson cycle has a lower compression ratio, along with higher expansion ratio inside engine cylinders. This system uses less energy to form fuel-air mixtures, and releases more energy.
A lighter, more free-flowing oil (0W-20) is also used, reducing friction energy loss and oil pump power requirements.
Two additional systems are added to the RX 450h's Lexus Hybrid Drive
powertrain, an exhaust-heat recovery system to reduce engine warm-up
periods (optimizing engine start-stop times, particularly in cold
conditions),
and a cooled exhaust gas-recirculation system to reduce fuel pumping loss
The electric motors use the first automotive application of liquid
cooling on both sides of the high-current transistors, allowing greater
contribution from the electric motors versus the gasoline engine.
Fuel efficiency for the RX 450h, according to EPA testing, is increased by twenty percent over the previous RX 400h.
Initial manufacturer data pointed to an increase of at least eight percent over the prior model.
In the U.S., the RX 450h is certified with a 2009 EPA fuel economy
rating of 32 mpg city, 28 highway for the FWD model, and 30 mpg city, 28
highway for the AWD model.
This 30 mpg combined rating compares with the 20 mpg combined rating of the non-hybrid RX model.
The powertrain is linked to an instrument panel Eco light indicator,
which enables drivers to monitor their fuel efficiency as it correlates
with accelerator modulation.
For 2013, RX450h models get a new “Sport” mode to complement the Normal,
Eco, and EV drive modes found in the current RX hybrid. When engaged,
Sport mode not only modifies the throttle and electric-power-steering
settings for faster response, but also is said to provide less-intrusive
operation of the car’s stability- and traction-control systems. That’s a
welcome change; we often find ourselves filling otherwise-serene Lexus
cabins with the sound of angry beeps when attempting any sort of
enthusiastic maneuver. Sport mode also changes the instrument panel’s
illumination from a peaceful hybrid blue hue to a fiery red, a touch
we’re not entirely convinced isn’t an attempt at subliminal political
commentary.
Current Lexus RX 450h
The Lexus RX 450h's 3.5-liter gas V6 engine and battery-pack-driven
electric motors/generators yield an impressive total output of 295 hp.
All that thrust runs through a specialized continuously variable
transmission (CVT), and despite its extra pounds, the hybrid RX is
still plenty quick. Fuel economy estimates stand at 30 mpg combined with
standard front-wheel drive, or 29 mpg combined with optional all-wheel
drive.
Standard luxury features include 18-inch alloy wheels, a power
liftgate, keyless ignition/entry, a power tilt-and-telescoping steering
wheel, dual-zone automatic climate control and a nine-speaker sound
system with an iPod/USB interface. A Sport driving mode is also
standard, which changes steering effort, throttle response and
transmission shifts for a livelier drive. Options (many grouped in
packages) include a blind-spot warning system, leather upholstery,
heated and cooled front seats, a navigation system, a rear DVD
entertainment system and a rearview camera.
