| First shown in Europe at Geneva, the Lexus
LS 460 is the fourth incarnation of the flagship LS model since 1989,
and incorporates a very high level of integration of vehicle systems.
A key development is in safety, where Lexus has worked to the principle
of “accident avoidance through anticipation.”
Continuing to blur the distinction between active and passive safety,
Lexus says its pre-crash system includes four world firsts:
• Advanced obstacle detection system
• Emergency steering assist
• Rear pre-crash safety system
• Driver monitoring system.
Mercedes fits a pre-crash system to the S-Class and the new E-Class, which
adjusts seat position, pre-tensions seatbelts and closes all windows and
sunroof if the car, interrogating data from the ESP and brake assist systems,
believes an impact is imminent.
The Lexus advanced obstacle detection system relies on a combination of
millimetre-wave radar and stereo imaging cameras to detect objects in
front of the car, including pedestrians and animals. Should pre-crash
determine a potential impact, an alarm alerts the driver to the danger.
If then it is decided that impact is unavoidable, the seatbelts are pre-tensioned
and the brakes applied to mitigate the effects of the collision.
The Lexus LS460 features the world's first
eight-speed automatic transmission
Emergency steering assist improves steering response in a critical situation
by combining the effects of several systems: variable gear ratio steering,
adaptive suspension, braking and electronic chassis controls. The driver
is provided with the most direct steering gear ratio appropriate, and
the car best set up to respond to driver inputs.
Rear pre-crash again uses millimetre-wave radar to detect approaching
vehicles. Algorithms process information such as range and closing speed
and if the system determines a high probability of collision, seatbelts
are pre-tensioned and the front head restraints moved upwards and forward
to reduce the likelihood of whiplash.
Driver monitoring in this instance does not serve to combat driver fatigue,
rather to ensure that they are watching the road. A miniature camera mounted
on the steering column monitors the driver’s face: if pre-crash
detects an obstacle up ahead but the camera sees the driver not looking
in that direction, pre-crash triggers an alarm and gently applies the
brakes.
Another world-first for this car is the eight speed automatic transmission.
It is mated to a 4.6-litre V8 engine, novel in itself for using two fuel
injectors per cylinder – one in the combustion chamber and one in
the intake port – and electric motor drive for the variable valve
timing systems instead of hydraulics. Lexus says this improves response,
thus engine flexibility.
|
|
