Dynamic Torque Management for Four-Wheel Drive Engagement

The patent implements dynamic torque management by continuously monitoring vehicle operating conditions (acceleration requests, vehicle speed, yaw rate) and adjusting the torque provided by the drive unit in real-time. The control system dynamically adapts torque limits based on whether four-wheel drive is engaged or disengaged, allowing high torque delivery when four-wheel drive is active to improve acceleration, while automatically reducing torque limits when four-wheel drive is disengaged to prevent excessive wheel slip.

The patent employs feedback control mechanisms where the electronic control unit continuously monitors vehicle dynamics parameters including wheel slip, yaw rate, and acceleration requests. Based on this feedback, the system adjusts the torque provided by the drive unit to maintain optimal performance. When four-wheel drive is disengaged, the feedback loop detects increased wheel slip and automatically reduces torque delivery to prevent loss of traction, thereby resolving the contradiction between maintaining high drive performance and preventing excessive slip.

The patent implements preliminary action by predicting when four-wheel drive engagement will be necessary based on monitored vehicle conditions such as acceleration requests, current torque levels, and drivetrain state. The control system proactively prepares for engagement scenarios and maintains four-wheel drive in a ready state only when predicted to be needed, rather than continuously engaging it. This predictive approach allows the system to maintain traction control reliability while minimizing unnecessary engagement time and associated energy consumption.

The patent dynamically changes operating parameters including torque limits, engagement timing, and drive mode selection based on real-time vehicle conditions. By adjusting these parameters optimally, the system achieves reliable traction control only when necessary, rather than maintaining constant four-wheel drive engagement. This parameter optimization resolves the contradiction by providing high reliability traction control during critical moments while minimizing overall energy consumption through selective engagement based on actual vehicle needs.

The patent applies preliminary action by pre-conditioning the drivetrain for rapid four-wheel drive engagement. The control system monitors vehicle conditions continuously and prepares the torque delivery system in advance of actual engagement needs. When engagement is initiated, the torque build-up follows an optimized trajectory that rapidly reaches required levels, minimizing the temporary period during which traction control might be compromised. This preparatory approach enables fast engagement response while maintaining reliable traction control throughout the transition.

The patent implements dynamic torque management during the engagement transition, where the torque build-up profile is continuously adjusted based on real-time vehicle conditions. Rather than using a fixed engagement timeline, the system dynamically adapts the rate of torque increase to match actual vehicle needs and drivetrain response characteristics. This dynamic approach allows the system to achieve rapid engagement response while ensuring torque levels are appropriately managed during the transition period, maintaining reliable traction control throughout the engagement process.