Automatic Transmission Lockup Control for High-Resistance Starts
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Solution Overview
Problem
Existing lockup control systems in automatic transmissions face challenges in maintaining fuel economy and reducing driver discomfort during lockup engagement, particularly when starting on roads with high traveling resistance, as they often result in premature lockup engagement leading to sudden engine rotation decreases and discomfort.
Innovation Solution
A lockup control device with a determination unit, engagement continuation unit, and start delay unit that starts lockup engagement when vehicle speed reaches a predetermined speed, continues engagement if the speed meets a determination vehicle speed, and restarts engagement when the speed exceeds a restart vehicle speed set higher than the start speed, thereby managing lockup engagement based on traveling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lockup engagement is executed based on normal lockup control when acceleration requirement condition is not satisfied (large traveling resistance), then fuel economy improvement is achieved, but lockup capacity occurs in lower vehicle speed range causing driver discomfort
Solution Approach 1:
The control device determines in advance whether the vehicle is in a high traveling resistance state by monitoring acceleration requirements. When high resistance is detected, the control device preliminarily adjusts the lockup control strategy by setting a higher lockup start vehicle speed, preventing premature lockup engagement before the vehicle gains sufficient momentum to overcome the resistance.
Solution Approach 2:
The invention changes the lockup start vehicle speed parameter dynamically based on traveling resistance conditions. Under high traveling resistance conditions (when acceleration requirement is not satisfied), the lockup start vehicle speed is set to a higher value than under normal conditions. This parameter adjustment delays lockup engagement until the vehicle reaches a speed where engagement will not cause sudden engine rotation decreases and driver discomfort.
2Object-affected harmful factors
If lockup engagement is delayed to prevent driver discomfort on high resistance roads, then driver comfort is improved, but energy consumption reduction performance deteriorates
Solution Approach 1:
The lockup control strategy is made dynamic by continuously monitoring vehicle acceleration and determining traveling resistance conditions in real-time. The control device switches between different lockup start vehicle speed thresholds based on whether the acceleration requirement is satisfied, optimizing the balance between comfort and energy efficiency for each driving condition rather than using a fixed conservative threshold.
Solution Approach 2:
The control device uses feedback from acceleration sensors and vehicle state monitoring to determine traveling resistance conditions. Based on this feedback, the system automatically adjusts the lockup engagement timing - enabling earlier engagement when acceleration is sufficient (saving energy) and delaying engagement when acceleration is insufficient (maintaining comfort), thus resolving the contradiction through condition-based adaptive control.
Data Source
AI summary
The controller starts an output of an engagement instruction of the lockup clutch when a vehicle speed becomes a lockup start vehicle speed under a state where the lockup clutch is disengaged. When the vehicle speed, which is obtained a predetermined time after the output of the engagement instruction is started due to the vehicle speed becoming the lockup start vehicle speed, has reached a predetermined vehicle speed, the controller continues the output of the engagement instruction. When the vehicle speed has not reached the predetermined vehicle speed, the controller stops the output of the engagement instruction and restarts the output of the engagement instruction when the vehicle speed reaches a lockup restart vehicle speed which is set to a vehicle speed higher than the lockup start vehicle speed while the output is stopped.