Real Time AWD with Intelligent Control System
New for 2012, the CR-V offers Real Time AWD with Intelligent Control System™, which represents a major advancement to Honda's original Real Time 4WD system used in previous-generation models. The more compact and efficient Real Time AWD introduces a high degree of four-wheel-drive sophistication in rain, snow, dirt roads and dry pavement. System operation is completely automatic and virtually transparent in smoothness. Unlike some four-wheel-drive systems that require the driver to select a drive mode based on the perceived need, Real Time AWD's automatic operation means the system is always ready to transfer torque to the rear wheels, allowing the driver to focus more on driving when situations are demanding.
The capabilities of the system are prioritized to further support high fuel efficiency and all-around drivability on-road as well as off-road. Assisting the front wheels when it is beneficial, Real Time AWD instantly powers the rear wheels when starting from a stop, even on dry pavement, working in cooperation with Vehicle Stability Assist (VSA) and the new Motion-Adaptive Electric Power Steering (EPS). For comparison, the previous-generation Real Time 4WD was designed to allow the front wheels to slip a small degree before torque was transferred to the rear wheels and its primary benefit was at low speeds. Plus, it did not interact with VSA. The new Real Time AWD system can operate at all speeds when needed. When torque transfer to the rear wheels is not required such as when cruising, drive to the rear wheels is decoupled for reduced drag.
The Intelligent Control System function of Real Time AWD cooperates with the VSA and EPS to assist the driver in maintaining vehicle control. For efficiency, the electric motor activating the hydraulic pump is idled when not required, further reducing drag within the system and helping to reduce energy consumption. Compared to the previous model's Real Time 4WD, the new Real Time AWD design weighs 17 percent less (approximately 36 pounds total system weight) and has 60 percent less rotational drag compared to the previous-generation's Real Time 4WD system.
The CR-V's all-wheel drive system's major components consist of the conventional front-wheel-drive system, a compact transfer case that distributes torque to a propeller shaft running the length of the vehicle, the rear differential, a new electronically-controlled hydraulic pump, a multi-plate clutch, and left and right rear-wheel driveshafts.
The previous-generation Real Time 4WD system was mechanically actuated using a pair of hydraulic pumps (one driven by the front wheels and one driven by the rear wheels) along with a ball cam mechanism to operate the clutch that sent power to the rear wheels. If the front wheels began to turn faster than the rear wheels, as would be the case if they were spinning on snow or ice, the difference in pressure between the two pumps would cause the clutch to be engaged, sending power to the rear wheels. The ball cam mechanism was designed to help speed engagement. The system was designed to react to front wheelspin quickly and then send a portion of the vehicle's power to the rear wheels.
The new Real Time AWD still uses a multi-plate clutch, similar to the clutches used in Honda automatic transmissions, to connect the propeller shaft to the rear differential. But in place of the twin hydraulic pumps and ball cam mechanism used previously, the system now uses an electric motor driving a single hydraulic pump, which operates the clutch. The electric motor is controlled by the Intelligent Control System, which means that the system can actively apportion power based on the conditions. The system doesn't merely react to front wheelspin; it minimizes wheelspin before it happens by sending power to the rear wheels accordingly.
When starting on snow for example, the system sends power to the rear wheels right from the start, minimizing the potential for front wheelspin. The system can also detect when the CR-V is climbing a hill and send a greater amount of power to the rear wheels in cooperation with the newly added Hill Start Assist feature. Hill Start Assist maintains brake pressure briefly after the brake pedal is released, giving the driver time to accelerate and smoothly resume motion. The Intelligent Control System instantly assesses the road's slope angle using a G-sensor and the level of grip as detected by VSA in case of wheel spin, allowing added initial apportioning of torque to the rear wheels for smooth starts.
In summary, Real Time AWD offers the optimal balance of confident capability and user friendliness in a lightweight and fuel-efficient design. The driver can simply step on the accelerator and let the system maximize use of available grip and climbing capability.
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