Friction Clutch Torque Control at Low Temperatures
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Solution Overview
Problem
The existing methods for controlling automated drive trains fail to prevent the friction clutch from slipping at low temperatures, as the coefficient of friction of the clutch lining decreases, leading to reduced engine torque transmission.
Innovation Solution
Adapting the engine torque based on the detected clutch temperature using a temperature model and friction value map, which eliminates the need for a temperature sensor and ensures reliable torque transmission by limiting the engine torque to the maximum permissible value associated with the coefficient of friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engine torque is increased to improve power transmission, then the productivity increases, but the friction clutch slips at low temperatures due to reduced coefficient of friction
Solution Approach 1:
The patent implements dynamic adaptation of engine torque based on real-time clutch temperature monitoring. The control unit continuously adjusts the maximum permissible engine torque according to the detected clutch temperature, ensuring optimal power transmission while preventing clutch slip at low temperatures. This dynamic adjustment resolves the contradiction by making the torque limit adaptive rather than fixed.
Solution Approach 2:
The patent employs a feedback mechanism where the control unit monitors clutch temperature and uses this information to adjust the engine torque limit. The temperature sensor provides continuous feedback about clutch state, and the control unit responds by modifying the maximum permissible torque accordingly. This closed-loop control ensures that power transmission is maximized when safe and prevented from causing clutch slip when temperatures are low.
2Measurement precision
If a temperature sensor is installed in the clutch to monitor temperature, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent introduces a control unit as an intermediary that receives temperature data from a sensor and processes this information to determine the maximum permissible engine torque. The control unit acts as a mediator between the temperature measurement and the engine torque control, allowing the system to benefit from precise temperature monitoring while keeping the sensor and clutch structure relatively simple. The control unit contains the complexity of the control logic rather than requiring complex modifications to the clutch itself.
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 prevents clutch slippage at any temperature by reducing the maximum engine torque at low temperatures, allowing for reliable torque transmission and extending the usability of friction linings with low coefficients of friction.
Implementation Method 1
the crankshaft (3) is connected to a transmission input shaft (5) via a friction clutch (4)
Implementation Method 2
a temperature model in a control unit for predicting the temperature of a clutch system
Data Source
Figure 1
AI summary
The invention relates to a method for controlling the drivetrain of a motor vehicle, comprising an internal combustion engine driving a crankshaft with a predetermined engine torque, wherein the crankshaft is connected to a transmission input shaft of a gearbox via a friction clutch for driving the drivetrain. In a method in which slippage of the friction clutch is reliably prevented even at low temperatures, the engine torque of the internal combustion engine is changed when the temperature of the friction clutch changes.