"Integrated Dynamic Drive System
The new RAV4 is available with either front-wheel drive or the Integrated Dynamic Drive System, an upgraded version of Toyota’s advanced all-wheel drive technology featuring a new Sport mode.
The Integrated Dynamic Drive System is a sophisticated, high-speed interactive management system which coordinates control of the RAV4’s Dynamic Torque Control AWD, Vehicle Stability Control (VSC) and Electric Power Steering (EPS) systems to enhance the compact SUV’s performance, handling and safety.
Using information from various sensors (speed, steering angle and yaw rate), the Dynamic Torque Control AWD system continuously controls the torque transfer between the front and rear wheels via an electromagnetically controlled coupling positioned in front of the rear differential.
Front to rear torque distribution can vary from 100:0 to 50:50, with front-wheel drive (100:0) automatically engaged under normal driving conditions to improve fuel consumption.
In normal mode -when neither Sport mode nor Lock mode are activated- torque transfer to the rear wheels now takes place not only when the front wheels are beginning to spin on slippery surfaces (as in the third generation RAV4) but also when the system detects understeer during cornering on road. As a result, the overall agility and driving performance of the vehicle is enhanced during both on- and off-road driving.
When the new Sport mode is selected, torque transfer to the rear wheels begins even before understeer develops. From the moment the steering wheel is turned, the Dynamic Torque Control AWD System operates a newly developed pre-torque control, automatically introducing a 90:10 front/rear torque distribution to help cornering force by transferring traction torque to rear.
If actual understeer develops, torque transfer to the rear wheels is automatically increased by up to 50% through a new yaw rate feedback control, to provide front tyres with improved lateral grip.
As well as activating the ‘Dynamic’ behaviour of the system’s front to rear torque transfer, the new Sport mode also decreases the RAV4’s power steering assistance by 20% and, depending on version, sharpens throttle response and offers higher revs for a more dynamic, sporting driving experience.
For off-road driving, the system incorporates an AWD Lock button. This allows drivers to lock torque distribution in a fixed, 50:50 ratio at speeds up to 40 km/h. Above this speed, the system automatically reverts to Normal mode.
From Integrated Active Drive System to Integrated Dynamic Drive System
The third generation RAV4 used Integrated Active Drive System, in which torque control was managed by an Active Torque Control 4WD system. The new RAV4 now uses a Dynamic Torque Control AWD System.
Compared to the third generation car, the new RAV4 keeps the following functions:
- Starting Control: traction performance when starting on snowy or muddy roads is ensured by increasing the rear torque distribution up to 50%. At speed above 25 km/h, the driving control switches to normal driving control.
- Normal driving control: on highways or urban roads, the rear torque distribution is reduced to 0% to enhance fuel efficiency. When detecting slippery roads in which wheel skidding occurs, torque control is immediately activated to ensure driving stability.
- VSC co-operative control: When the front wheels skid and the vehicle runs outside the driver’s intended path, EPS assists for the turning direction (by creating a torque in the steering wheel in order to show to the driver the right manoeuvre to do ), and torque is distributed to the rear wheels.
- Braking control: AWD is cancelled to enhance the effects of ABS a and the VSC System.
- Lock mode control: when the driver pushes the LOCK mode switch. 50% of torque is transmitted to each axle to enhance escape performance in situations such as when the vehicle is stuck.
The new function added on top of these 5 control modes is:
- Cornering control: Yaw rate feedback control is used to adapt rear wheel torque to assist cornering performance by generating optimal drive force distribution and balancing the load between front/rear wheels. With Sport mode, from the first steering input, 10% of the torque is directed to the rear wheels at the start of the corner which can increase to a maximum of 50% during cornering to ensure driving stability and a fun to drive experience.
Thanks to cornering control, Sport mode helps the driver to maintain his intended trajectory and, at the end, have more enjoyable driving experience."