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RX 450h
The new RX 450h
luxury crossover introduces the
second generation Lexus Hybrid
Drive, a full hybrid system with
advanced powertrain technology
that delivers an unprecedented
combination of fuel economy, low
emissions and performance, well
beyond the scope of any of its
segment rivals.
All the full
hybrid system’s components have
been revised to achieve
dramatically improved
efficiency: fuel consumption is
reduced by 28 per cent, while at
the same time engine power is 10
per cent greater than in the RX
400h. The improvements Lexus has
made also contribute to
substantially lower emissions,
quieter operation and greater
driver satisfaction.
Total power
output is 295bhp, enabling a top
speed of 124mph and nought to
62mph acceleration in 7.9
seconds. This performance comes
with 44.8mpg combined cycle fuel
consumption and 148g/km CO2
emissions, a combination that
cannot be matched in the RX
450h’s class, not even by
smaller and less powerful
2.0-litre diesel models. This
has a direct impact on running
costs, for example in a 14 per
cent benefit-in-kind company car
tax rating – a level typically
associated with more modest
C-segment models, “eco” specials
and other hybrid vehicles, such
as the Toyota Prius.
Full Hybrid Drive
System Configuration
Lexus Hybrid Drive is a combined series/parallel full hybrid system that
comprises a highly efficient
petrol engine and two powerful
electric motors. As a full
hybrid the vehicle can operate
on its electric motors or petrol
engine alone, or with a
combination of both. Like its
predecessor, the RX 400h, the
new model’s second, rear-mounted
electric motor provides an
intelligent four-wheel drive
capability.
The system
combines distinct front and rear
driving units, with a power
control unit managing their
seamless, high-speed
interaction.
The front drive
unit features a 3.5-litre V6
petrol engine, a powerful
electric motor, generator, high
performance battery, power
control unit (PCU) 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 is
mechanically independent from
the front. It provides
four-wheel drive by means of a
second electric motor, which is
activated and continuously
adjusted by the Vehicle Dynamics
Integrated Management (VDIM)
system, working in conjunction
with the PCU.
Electric Motors
Although power from the front
and rear electric motors remains
the same as it was on the RX
400h, at 165bhp ( 167 DIN hp)
and 67bhp (68 DIN hp)
respectively, the improved
cooling of the PCU has increased
their continuous maximum torque
band width. This gives better
performance, in particular from
a standing start. The front and
rear motors now deliver maximum
torque of 335Nm and 139Nm from
zero rpm respectively, while the
range of the front motor’s
maximum toque is extended by
9mph and that of the rear by
22mph. |
