Clutch Slipping Point Estimation Under Drag Torque
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Solution Overview
Problem
Existing methods for estimating the clutch slipping point position in gearboxes, particularly in heavy-duty vehicles, are not reliable due to clutch drag torque issues, which can lead to inaccurate synchronization with the engine, making it difficult to determine the precise slipping point.
Innovation Solution
A method involving the application of a predetermined brake torque to prevent input shaft rotation when the clutch is fully disengaged, followed by moving the clutch towards an engaged position and using clutch transfer characteristics to define the slipping point position, ensuring accurate and controlled estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If clutch transfer characteristics are used to define slipping point position, then measurement precision is improved, but device complexity increases due to additional braking means and control mechanisms
Solution Approach 1:
The braking means is activated before the clutch engagement measurement to pre-establish the braked condition. This preliminary action ensures the input shaft is properly constrained before torque transfer begins, eliminating the need for complex real-time detection systems and simplifying the overall measurement approach while maintaining high precision
Solution Approach 2:
The braking means acts as an intermediary element between the clutch and the measurement system. By introducing this controlled braking mechanism, the system can accurately isolate and measure the clutch slipping point without the interference of uncontrolled input shaft rotation, thereby improving measurement precision while keeping the added complexity manageable
2Reliability
If clutch dragging is present during disengagement, then reliability of slipping point detection deteriorates, but applying braking means increases device complexity
Solution Approach 1:
The braking means applies a counteracting force to the clutch drag torque before the slipping point measurement begins. This preliminary anti-action neutralizes the harmful effect of clutch dragging, ensuring reliable detection of the slipping point without requiring complex real-time compensation algorithms or additional sensors
Solution Approach 2:
The braking means converts the harmful clutch drag torque into a beneficial controlled condition. By deliberately applying known brake torque, the system transforms the unpredictable drag torque into a controlled parameter that can be accounted for in the measurement, thereby improving reliability while adding only moderate complexity
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 approach provides a more reliable and swift estimation of the clutch slipping point position by eliminating drag torque effects, allowing for precise synchronization and verification of the desired slipping point torque, thereby improving clutch control.
Implementation Method 1
applying the braking means with a predetermined brake torque and so that the input shaft is not rotating
Data Source
Figure 1~2
Figure 3~4
AI summary
The present disclosure relates to a method for defining a clutch slipping point position(Xsp) of a clutch (2) in a gearbox (1), wherein the gearbox comprises an input shaft (3) and wherein the input shaft is arranged to be braked by a braking means (4), the method comprising: -determining (S1) if the clutch is dragging when the clutch is fully disengaged; -when it is determined that the clutch is dragging, applying (S2) the braking means with a predetermined brake torque (Tb) and so that the input shaft is not rotating; and thereafter: -moving (S3) the clutch from the fully disengaged position towards an engaged position; -determining (S4) when the input shaft starts to rotate with a predetermined rotation value indicative of a rotational speed of the input shaft; -registering (S5) a clutch position (Xb) in which the clutch is positioned when the predetermined rotation value is reached; -using (S6) a clutch transfer characteristics of the clutch, the predetermined brake torque (Tb) and the registered clutch position (Xb) to define the clutch slipping point position (Xsp).