Vehicle Clutch Control for Slope Stall Prevention
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Solution Overview
Problem
Existing vehicle clutch control systems face challenges in preventing overheating and engine stalling, especially when driving on steep slopes at low speeds, due to insufficient torque production and potential fuel efficiency deterioration.
Innovation Solution
A control device and method that determines the temperature of the clutch engaging portion and adjusts its state to prevent overheating by ensuring a torque is produced that exceeds the additional value of running and frictional resistance, using a determination unit and internal combustion engine control unit to manage the clutch and engine output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clutch is controlled to be in a semi-engaged state to prevent engine stall at low speed, then engine stall is prevented, but heat is generated at the engaging portion causing clutch overheat
Solution Approach 1:
The control device alternates between semi-engaged and engaged states periodically. When the clutch temperature reaches a predetermined threshold, the control switches from semi-engaged to engaged state, allowing the clutch to cool down. This periodic switching prevents continuous heat generation while maintaining engine operation stability.
Solution Approach 2:
The control device changes the clutch engagement parameter dynamically based on temperature conditions. At normal temperatures, the clutch maintains a semi-engaged state for smooth power transmission. When temperature exceeds the threshold, the engagement parameter is changed to a fully engaged state to reduce slippage and allow cooling, thus managing the temperature parameter.
2Temperature
If the clutch is brought into the engaged state to suppress heat generation, then clutch overheating is prevented, but engine stall may occur due to insufficient torque on steep slopes
Solution Approach 1:
The control device continuously monitors clutch temperature and provides feedback to the control unit. When the temperature reaches the predetermined threshold, this feedback triggers a state switch from semi-engaged to engaged. The system also monitors engine operation conditions to ensure that the engaged state does not cause engine stall, especially under high load conditions like steep slopes.
Solution Approach 2:
The clutch control system is made dynamic by allowing real-time switching between semi-engaged and engaged states based on temperature feedback. This dynamic adaptation enables the system to optimize between heat suppression and engine stability, adjusting the engagement state according to real-time operating conditions including temperature and load requirements.
3Temperature
If the driving torque is reduced to suppress heat generation, then clutch overheating is prevented, but fuel efficiency deteriorates due to unnecessary engine output increase
Solution Approach 1:
Instead of continuously reducing driving torque, the system uses periodic switching between semi-engaged and engaged states. This allows the clutch to cool down during engaged periods without maintaining reduced torque output, thereby suppressing heat generation while minimizing the impact on fuel efficiency during cooling periods.
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
This solution effectively suppresses clutch overheating, prevents engine stalling, and maintains fuel efficiency by ensuring sufficient torque is produced, even on steep slopes, thereby extending clutch lifespan and optimizing engine performance.
Implementation Method 1
heat is generated at an engaging portion between an input shaft and an output shaft, which heat is caused by slippage
Data Source
AI summary
An ECU executes a program including the steps of sensing a slope of a lane if an estimated temperature T of a clutch is higher than a predetermined threshold value (1) (YES in S100) (S102), calculating running resistance and friction resistance (S104), performing torque demand control (S106), controlling the clutch such that the clutch is engaged (S108), and performing normal control if the estimated temperature T of the clutch is lower than a predetermined threshold value (2) (YES in S110) (S112).