News - Mazda
Mazda i-Activ AWD uses predictive tech
Cold as ice:Mazda's predictive i-Activ all-wheel drive tech is available in different forms on the CX-3, CX-5 and the imminent new CX-9.
Simple, affordable tech drives Mazda’s i-Activ predictive AWD system
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4 February 2016
MAZDA’S rebranded i-Activ all-wheel drive system as found on its SkyActiv
models such as the CX-5 and all-new CX-9, uses software technology to improve
the effectiveness and efficiency of what is a relatively simple and inexpensive
alternative to rival products.
Speaking to GoAuto at the Mazda Ice Academy global media event in Colorado,
Mazda Motor Corporation assistant manager for drivetrain and powertrain
development Tetsushi Marutani revealed that the goal was to slash torque
transfer times, reduce lag, cut weight, and close the consumption gap that
exists between two-wheel and all-wheel drives.
“Previously, our all-wheel-drive system was about (increasing) performance
only,” he said. “Now our focus has moved to improving efficiency, but still
with best-possible performance too.”
Essentially the same design in terms of hardware as Mazda’s previous on-demand
AWD set-up, introduced with the original Mazda6 in 2002, i-Activ uses advances
in software to achieve its desired results.
Mr Tetsushi was also the brains behind the earlier system, and started work on
i-Activ when the SkyActiv technologies development started in earnest in Japan
There are two versions – a compact one for the CX-3 crossover and Japanese
home-market Mazda2/Demio AWD, and a larger and stronger one for vehicles from
the CX-5 to CX-9 SUVs.
The big news is that Mazda’s system is predictive. Building on the old system
that determined traction loss and then sent torque to whichever wheel needed it
according to wheel speed, engine RPM, air/fuel mixture present, gear shift
position, and accelerator pedal position, i-Activ now also collates engine,
transmission, steering, brake, and prevailing weather data.
More specifically, sensors ‘read’ the car’s steering torque and its electric
motor current levels, steering angle, electronic stability control longitudinal
g-force readings, ambient temperature, and even if the wipers are activated.
In all, some 27 sensors feed data to a central control module at a rate of 200
times per second, via an Active Torque Control Coupling, which is
electromagnetically activated. As these can all be tell-tale evidence that
traction loss may be imminent, i-Activ’s software then pre-empts tyre slippage
before it happens by sending drive to the wheel that is about to need it.
Mazda says that the upshot of this anticipation tech is more precise and safer
control, with the far-faster torque transfer already driving the wheels. And
since the inertia of slippage has been mitigated, less torque is required to
keep the wheels gripping, thus saving fuel.
Additionally, minute torque levels are constantly fed to the rear wheels so
there is no “backlash” when drive does kick in. Seamless operation is the goal.
Mr Marutani said that lag has not yet been totally eliminated, but that the
next generation of i-Activ due when the CX-5 is renewed in about two years time
will feature even quicker reaction times.
The physical hardware now weighs less (by at least 25kg – the total amount is a
secret, but it is believed that the CX-9’s system has dropped from 80kg to
54kg), with the SkyActiv-Drive six-speed automatic transmission featuring a
lightweight propeller shaft with a damper that cuts noise, vibration and
Also new is a smaller and lighter rear differential with smaller innards,
better cooling properties, a lower-viscosity synthetic oil, and detailed casing
improvements to reduce friction.
Mazda says the point of the i-Activ’s operation is to be completely invisible
to the driver – no lights, no switches, no tyre slipping – so that they won’t
even be aware that a potential traction hazard has been avoided or minimised.
While most rival on-demand systems from Toyota, Nissan, Honda, Volkswagen and
Audi were studied during development, Subaru’s Symmetrical AWD set-up was the
benchmark for i-Activ.