Clutch Torque Control for Slippery Road Starting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Starting a motor vehicle from a standstill on a slippery road surface poses challenges due to the risk of wheel slip, as existing systems require fine adjustment of clutch torque by the driver, which can be tricky and prone to errors, especially when the driver is unaware of the road conditions.
Innovation Solution
A system that determines the risk of a slippery road surface and adjusts the relationship between clutch torque and accelerator member position, reducing the sensitivity of clutch torque to accelerator input, allowing the driver to actuate the accelerator as if on a normal friction surface, thereby reducing the risk of wheel slip by decreasing clutch torque increases and slowing the torque reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the driver presses the accelerator pedal more to increase clutch torque for faster starting, then the vehicle starts more quickly, but the wheels may lose grip and spin on slippery road surfaces
Solution Approach 1:
The system changes the relationship parameter between accelerator pedal position and clutch torque based on detected road surface conditions. When slippery conditions are detected, the system modifies the torque multiplication factor or clutch engagement characteristics to reduce torque transmission sensitivity, allowing aggressive accelerator input without wheel spin while maintaining controlled torque delivery.
Solution Approach 2:
The system continuously monitors wheel slip conditions and road surface friction characteristics, using this feedback to dynamically adjust the clutch torque control strategy. When wheel slip is detected or low friction is anticipated, the system reduces clutch torque or modulates engagement to prevent loss of grip, then恢复正常 torque transmission when grip is restored.
2Reliability
If the driver manually fine-adjusts the accelerator pedal to control clutch torque on slippery surfaces, then wheel slip can be avoided, but the operation becomes tricky and errors are likely especially when the driver is unaware of road conditions
Solution Approach 1:
The system performs the complex task of clutch torque fine-adjustment automatically without requiring driver intervention. The control system monitors wheel slip and road conditions, then autonomously modulates clutch engagement and torque transmission to maintain optimal grip, freeing the driver from the need to manually fine-tune accelerator input while ensuring reliable wheel grip maintenance.
Solution Approach 2:
The control system acts as an intermediary between the driver's accelerator pedal input and the actual clutch torque delivery. It receives the driver's acceleration request, processes it through slip-control algorithms that consider current road conditions, and delivers the appropriately modulated torque to the clutch, thereby protecting the driver from the complexity of direct torque control while maintaining wheel grip stability.
3Power
If the clutch torque increases rapidly to provide strong acceleration, then the vehicle starts more forcefully, but the abrupt torque increase causes wheel spin on low-friction surfaces
Solution Approach 1:
The system dynamically adjusts the clutch torque delivery characteristics based on real-time wheel slip detection and road surface condition assessment. When slippery conditions are detected, the system modifies the torque ramp rate or engagement profile to provide smooth, progressive torque increase rather than abrupt application, preventing wheel spin while still delivering the power needed for effective starting.
Solution Approach 2:
The system anticipates potential wheel slip by detecting low-friction road conditions before the driver applies full accelerator input. When such conditions are predicted or detected, the system pre-adjusts the clutch engagement characteristics or torque multiplication to cushion against abrupt torque increases, preparing the drivetrain to handle aggressive acceleration requests without causing wheel spin.
Data Source
Figure 1
Figure 2~4
Figure 5
AI summary
A system for controlling an operation of starting a motor vehicle having an automated mechanical transmission as gearbox standing still on a road surface comprises an arrangement (42) adapted to determine, in a said operation of starting, whether there is a risk that said road surface is slippery and send information about this determination to a control unit (28). The control unit (28) is adapted to change a determined relationship between a clutch torque and an accelerator member position from a first such relationship in a first mode to a relationship making said clutch torque less sensitive to changes of the position of the accelerator member (27) of the vehicle in a second mode when said arrangement has determined that said risk exists.