Shift Controller Clutch Stroke Detection for Engagement Shock Prevention
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Solution Overview
Problem
In shift time controllers for vehicles with internal combustion engines and manual transmissions, it is challenging to prevent clutch engagement shocks due to thermal expansion and wear of the clutch disc, making it difficult to accurately position the half-clutch switch.
Innovation Solution
A shift controller that includes a detection mechanism for clutch stroke, a rotation synchronization mechanism to synchronize engine and transmission speeds, and a setting/learning mechanism to set and learn the shift operation position based on predetermined variation thresholds, ensuring appropriate synchronization control during clutch engagement and disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a half-clutch switch is used to detect the shift operation position, then rotation synchronization control can be started at the appropriate timing, but thermal expansion and wear of the clutch disc make it difficult to dispose the switch at an appropriate position, causing shock during clutch engagement
Solution Approach 1:
The patent replaces the mechanical half-clutch switch with a sensor-based detection system that measures clutch stroke position electronically. This substitution eliminates the need for precise mechanical switch positioning that is affected by thermal expansion and wear, while maintaining accurate detection of the shift operation position for initiating rotation synchronization control.
Solution Approach 2:
The patent changes the detection parameter from mechanical switch contact position to electronic sensor measurement of clutch stroke position. By using a sensor to detect the clutch stroke and comparing it with stored shift operation position data, the system achieves accurate position detection without being affected by the physical degradation issues that plague mechanical switches.
2Duration of action of stationary object
If the clutch disc thickness decreases due to wear, then the clutch disc becomes thinner, but this makes it difficult to dispose the half-clutch switch at an appropriate position
Solution Approach 1:
The patent replaces the mechanical half-clutch switch with an electronic sensor system that measures clutch stroke position. This substitution ensures that position detection accuracy is maintained throughout the entire service life of the clutch disc, regardless of wear-induced thickness changes, because the sensor measures the stroke position rather than relying on a fixed mechanical contact point on the clutch disc.
3Speed
If rotation synchronization control is started at the half-clutch position, then engine rotational speed can be synchronized with input shaft rotational speed, but shock occurs when the clutch is fastened due to improper switch positioning
Solution Approach 1:
The patent replaces the mechanical half-clutch switch with an electronic sensor-based detection system. This allows for more precise and reliable detection of the shift operation position, ensuring that rotation synchronization control is initiated at the correct clutch stroke position. The electronic system is not affected by thermal expansion or wear, thereby preventing the engagement shock that occurs with improperly positioned mechanical switches.
Solution Approach 2:
The patent implements a feedback mechanism where the sensor continuously monitors the clutch stroke position and compares it with the stored shift operation position data. This feedback ensures that rotation synchronization control is initiated at the precise moment when the clutch stroke reaches the shift operation position, optimizing the synchronization process and preventing engagement shock.
Data Source
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AI summary
A shift controller (ECU 8) includes, functionally, a detection part 811 that detects a clutch stroke St via a clutch stroke sensor 71 and a rotation synchronization part 815 that performs rotation synchronization control to synchronize a rotational speed Ne of an engine 1 with an input shaft rotational speed Ni of a manual transmission 2. When a clutch 3 is switched from an engaged state to a disengaged state, the rotation synchronization part 815 starts the rotation synchronization control under a condition in which the detection part 811 detects that the clutch stroke St reaches a position of a first stroke ΔSt1 that is set in advance on a side more engaged than a shift operation position St0 where a shift operation is performed while the clutch 3 is in the disengaged state. Thus, the rotation synchronization control is started while the clutch stroke St is at an appropriate position, accordingly a shock when the clutch 3 is fastened can be certainly prevented.