Vehicle Transmission Pre-Synchronization Control
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Solution Overview
Problem
Conventional control methods for vehicle automatic transmissions struggle to simultaneously improve drive power response and reduce synchronization shock when a one-way clutch is brought to a synchronized state, as they require instantaneous changes in engine torque control, making it difficult to achieve both quick power response and reduced shock.
Innovation Solution
A control apparatus and method that includes a pre-synchronization control to transmit torque through a predetermined friction engagement device, maintaining the one-way clutch in an idling state and gradually changing its rotational direction towards synchronization, and a post-synchronization control to adjust torque capacity and output torque accordingly, ensuring the clutch is synchronized before power is transmitted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If engine torque increase control is executed to promote one-way clutch synchronization, then drive power response is improved, but synchronization shock increases
Solution Approach 1:
The system executes preliminary synchronization control before the one-way clutch is fully engaged. During this phase, torque is gradually applied through the friction engagement device to pre-synchronize the clutch, reducing the shock when full engagement occurs. This preliminary action allows the system to prepare the clutch for synchronization while maintaining drive power response.
Solution Approach 2:
The control system dynamically adjusts torque application based on the synchronization state of the one-way clutch. By continuously monitoring clutch engagement progress and adjusting torque in real-time, the system optimizes both drive power response and minimizes synchronization shock throughout the engagement process.
2Object-generated harmful factors
If engine torque is controlled to reduce synchronization shock, then shock is reduced, but drive power response deteriorates
Solution Approach 1:
Instead of waiting until the last moment to apply torque, the system begins torque application in advance during the preliminary synchronization phase. This allows drive power to be transmitted earlier while the clutch is still synchronizing, improving response without causing shock at full engagement.
Solution Approach 2:
The control system maintains continuous torque application throughout the synchronization process rather than interrupting or delaying it. This continuous action ensures drive power is consistently transmitted while the clutch transitions from idle to synchronized state, improving response while managing shock through controlled torque progression.
3Speed
If instantaneous change from torque increase to torque decrease control is executed, then both drive power response and synchronization shock control are targeted, but control complexity increases and response time is extended
Solution Approach 1:
The control system uses dynamic, continuous adjustment of torque rather than abrupt transitions between increase and decrease modes. This dynamic approach simplifies control logic while achieving both fast response and shock reduction through smooth torque progression based on real-time clutch state feedback.
Solution Approach 2:
By initiating torque application during the preliminary synchronization phase rather than waiting for full engagement, the system eliminates the need for instantaneous control reversals. The torque is gradually increased from the start, simplifying control while improving response and reducing shock.
Data Source
AI summary
In a control apparatus and a control method for a vehicle automatic transmission in which a plurality of gears with different speed ratios are achieved by selectively engaging a plurality of friction engagement devices and a one-way clutch, if an acceleration request is made in the case where the one-way clutch is in an idling state when a first predetermined gear is to be achieved by engaging the one-way clutch, a pre-synchronization control is executed to transmit torque through a predetermined friction engagement device used to achieve a second predetermined gear at which the one-way clutch is maintained in an idling state, and to continue to change a rotational direction of the one-way clutch toward a rotational direction in which the one-way clutch is brought to a synchronized state, according to the acceleration request.