Automatic Transmission Select Pressure Release for Shock Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional automatic transmission hydraulic pressure control devices experience select shock during driver operations from the D range position to the P range position due to sudden hydraulic pressure loss when the clutch engaged at the D range position loses pressure during R→P select operations.
Innovation Solution
A select control device for automatic transmission that includes a controller performing pressure release control to gently decrease the engagement capacity of the starting clutch during select operations from the D range position to the N range position, and continuing this control during subsequent select operations from different travel range positions to suppress select shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic pressure control is performed based on D→N select operation only, then select shock is suppressed during D→N operation, but select shock occurs during R→P operation due to sudden hydraulic pressure loss
Solution Approach 1:
The controller is designed to universally handle multiple select operation types (D→N, R→P, and continuous operations) using a single pressure release control mechanism. The control unit identifies the engaged starting clutch and applies gentle pressure release regardless of the specific operation type, making the system adaptable to various select scenarios while maintaining shock suppression reliability.
2Speed
If the clutch engaged at D range position suddenly loses hydraulic pressure during R→P operation, then the select operation completes quickly, but select shock occurs
Solution Approach 1:
The controller implements beforehand cushioning by detecting when a starting clutch is engaged and applying pressure release control before the select operation completes. This gradual hydraulic pressure reduction cushions the transition, preventing sudden pressure loss and the resulting select shock while maintaining acceptable operation speed.
Solution Approach 2:
The system dynamically adjusts hydraulic pressure release based on real-time detection of engaged starting clutches. The pressure release control is applied selectively to the appropriate clutch during different select operations (D→N or R→P), making the pressure release profile adaptive to the current operational state rather than fixed.
3Reliability
If pressure release control is applied during continuous select operations, then select shock is suppressed, but control complexity increases
Solution Approach 1:
The controller uses feedback from the range position detection to continuously monitor which starting clutch is engaged. Based on this feedback, the control unit dynamically applies pressure release control to the appropriate clutch during continuous select operations (D→N→R→P), suppressing select shock while managing complexity through responsive rather than predetermined control logic.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively suppresses select shock during continuous select operations by gradually releasing hydraulic pressure, ensuring smooth transitions between travel and non-travel range positions, thereby enhancing the driving experience.
Implementation Method 1
the controller performs pressure release control to gently decrease the engagement capacity of the starting clutch that is engaged in the first travel range position
Data Source
AI summary
A select control device for an automatic transmission includes a select lever and a controller. The select lever is configured to select a range position in response to a select operation by a driver. The controller is configured to, when a first select operation from a first travel range position to a non-travel range position is performed, perform pressure release control that decreases at a prescribed descending gradient an engagement capacity of a starting clutch that is engaged in the first travel range position. The controller has a select hydraulic pressure control unit configured to continue the pressure release control during a second select operation from a second travel range position that is different from the first travel range position to the non-travel range position after the first select operation.