Clutch Contact Point Detection via Input Shaft Acceleration
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Solution Overview
Problem
Existing methods for determining the contact point of an automatically controlled clutch in vehicles are inefficient, often requiring the gearbox to be stationary and relying on rotation speed sensors that cannot detect low speeds accurately, leading to incorrect or delayed detection of the clutch's contact point.
Innovation Solution
A method that accelerates the gearbox input shaft to a detectable speed, calculates the friction coefficient, and determines the clutch contact point by monitoring the torque transmitted when the clutch closes, allowing for accurate detection without halting the gearbox and at speeds where the speed sensor is reliable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the rotation speed sensor on the gearbox input shaft is used to detect the contact point, then the contact point detection can be performed, but the detection is inaccurate at low speeds because the sensor cannot detect speeds below a certain threshold
Solution Approach 1:
The patent changes the operating parameter of the gearbox input shaft from stationary (0 RPM) to rotating at a speed above the sensor's detection threshold. By accelerating the input shaft to a detectable speed before contact point determination, the rotation speed sensor can accurately detect the contact point when the clutch engages, resolving the issue of insufficient low-speed detection capability.
2Measurement precision
If the gearbox input shaft is halted before contact point determination, then the contact point can be detected when the shaft is stationary, but the process takes too long and affects vehicle operation
Solution Approach 1:
The patent performs preliminary acceleration of the gearbox input shaft to a detectable speed before the contact point determination is needed. This preliminary action ensures that when the clutch contact point needs to be determined, the shaft is already rotating at a speed suitable for accurate sensor detection, eliminating the need to halt the shaft and reducing the time required for contact point determination during actual operation.
3Measurement precision
If the clutch contact point is determined when the gearbox is in neutral position with stationary input shaft, then the estimation can be performed, but the method is too slow and the detected point is not the actual contact point
Solution Approach 1:
The patent changes the operational state of the gearbox from stationary neutral position to rotating neutral position. By maintaining the gearbox in neutral position (disconnected from engine and wheels) but rotating the input shaft above the sensor's detection threshold, the system achieves both accurate contact point detection and operational readiness, resolving the contradiction between detection accuracy and determination speed.
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
Enables quick and accurate determination of the clutch contact point during motion, reducing unwanted jerking and wear on the power train, and allowing for smoother gear changes without the need to halt the gearbox.
Implementation Method 1
a rotation speed sensor on the gearbox input shaft registers a speed
Data Source
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AI summary
The present invention relates to a method for determining the contact point for a clutch in a vehicle comprising an engine, a clutch, powered wheels and a gearbox. The gearbox comprises a first gearbox component which is connected to the clutch and disconnectable from the powered wheels. The method comprises the steps of - estimating (405) a friction torque for said first gearbox component, whereby said torque transmitted by the clutch is a function of said estimated friction torque, - closing (407) said clutch, whereby a representation of a torque transmitted by the clutch is determined for a plurality of positions for said clutch, - determining (409) said contact point by means of said determined representation of torque transmitted, - and the further step (402), before the closure of the clutch, of accelerating said first gearbox component if its rotation speed is below a certain value. The invention also relates to a system and a vehicle.