Clutch Control System for Engine Hunting Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing clutch control systems, such as those described in Japanese Patent Application Publication No. 2002-286060, fail to provide satisfactory riding feeling during low engine rotational speed, particularly on steeply sloping roads, and suffer from unstable clutch behavior due to engine rotational speed hunting during rotational speed suppression control, leading to excessive loads on the engine and clutch.
Innovation Solution
A clutch control system that includes a rotational speed control unit for executing rotational speed suppression control and a clutch position control unit, which adjusts clutch engagement based on engine rotation information, switching between a first and second clutch position control mode depending on the execution of rotational speed suppression control, to minimize the influence of engine rotational speed hunting on clutch behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clutch is controlled to engage slowly or with small engagement amount when engine rotational speed is low (prior art), then the clutch engagement is optimized for accelerator stepping, but the riding feeling becomes unsatisfactory during low-speed travel on steeply sloping roads
Solution Approach 1:
The clutch control system dynamically adjusts the clutch engagement amount based on the current operational mode detected by the control unit. When acceleration demand is detected (accelerator opening degree increases), the clutch engages with larger amount for rapid acceleration. When deceleration is detected (accelerator opening degree decreases), the clutch engages slowly to prevent hunting. This dynamic adaptation resolves the contradiction between optimized engagement and riding feeling across different driving conditions.
Solution Approach 2:
The control unit changes the clutch engagement amount parameter based on detected operational conditions. During acceleration demand, the engagement amount is increased to improve response and riding feeling. During deceleration, the engagement amount is reduced to prevent hunting. This parameter adaptation allows the system to achieve both optimized engagement and satisfactory riding feeling in different scenarios.
2Reliability
If the clutch engagement is maintained when engine rotational acceleration is negative (prior art), then the clutch engagement is protected during deceleration, but unstable clutch behavior occurs due to engine rotational speed hunting during rotational speed suppression control
Solution Approach 1:
The control unit continuously monitors engine rotational acceleration and rotational speed to detect hunting conditions. When hunting is detected (repeated positive and negative acceleration cycles), the control unit adjusts the clutch engagement amount to prevent unstable behavior. This feedback mechanism allows the system to maintain reliability during normal deceleration while preventing instability during hunting conditions.
Solution Approach 2:
The control unit proactively detects hunting conditions by monitoring engine rotational acceleration patterns and takes preliminary action by adjusting clutch engagement amount before unstable behavior fully develops. This prevents the half-clutch state from being sustained and avoids excessive loads on the engine and clutch.
3Speed
If the clutch responds rapidly to engine rotational speed changes, then the clutch actuation response is sufficient during low-speed travel, but the clutch operation undergoes hunting and sustains half-clutch state during engine rotational speed hunting
Solution Approach 1:
The clutch control system dynamically adjusts its response characteristics based on operational conditions. During normal operation, the clutch responds rapidly to engine rotational speed changes for sufficient actuation response. During detected hunting conditions, the system dynamically reduces the response gain to prevent the clutch from following the hunting oscillations, thereby maintaining stability while preserving rapid response capability during normal operation.
4Force
If rotational speed suppression control is executed to suppress engine rotational speed, then loads on engine and clutch are lightened, but hunting of engine rotational speed occurs causing repeated inversion of engine rotational acceleration
Solution Approach 1:
The control unit monitors engine rotational acceleration during rotational speed suppression control to detect hunting conditions characterized by repeated positive and negative acceleration inversions. When hunting is detected, the control unit adjusts the clutch engagement amount to dampen the oscillations and stabilize engine rotational speed, thereby maintaining load reduction benefits while preventing unstable hunting behavior.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A clutch control system includes a hunting determining unit (10, S3, S40) that determines whether or not a hunting condition, under which hunting occurs in an engine rotational speed of an engine (2), is met, and a clutch position control unit (10, S10 to S19, S21 to S26, S31 to S36). The clutch position control unit (10, S10 to S19, S21 to S26, S31 to S35) executes a first clutch position control, which is in accordance with engine rotation information, on the clutch (3) if the hunting determining unit (10, S3, S40) determines that the hunting condition is not met, and executes a second clutch position control, which is lower in response to the engine rotation information than the first clutch position control, on the clutch (3) if the hunting determining unit (10, S3, S40) determines that the hunting condition is met.