Clutch Solenoid Current Oscillation for Fast VKP Calibration
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Solution Overview
Problem
Existing methods for setting the control reference value for a hydraulic multi-plate clutch in vehicle transmissions are not accurate or efficient, particularly in learning and updating the volumetric kiss point (VKP) during manufacturing and while the vehicle is in operation.
Innovation Solution
A method involving the application of a test current with a predetermined amplitude and frequency to a solenoid valve, followed by a checking current that oscillates based on the central value, to determine the VKP by comparing pressure amplitudes within a reference range, with iterative adjustments to ensure accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to set the volumetric kiss point (VKP) for clutch control, then the control reference value can be established, but the learning and setting process is slow and inaccurate
Solution Approach 1:
The patent applies periodic triangular wave currents to the solenoid valve during VKP learning. The controller generates test currents with specific frequencies and amplitudes that periodically vary, allowing rapid detection of pressure changes. This periodic action enables the system to quickly identify the VKP point through multiple oscillations within a short time frame, significantly reducing the learning time while improving accuracy through repeated measurements.
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors clutch pressure in response to applied test currents and adjusts subsequent currents based on the observed pressure responses. The system uses the pressure feedback to determine when the VKP is reached and to refine the measurement through iterative checking currents, enabling rapid and accurate VKP identification without time-consuming conventional methods.
2Productivity
If the clutch control reference value is not accurately set, then the manufacturing process can proceed quickly, but the clutch control accuracy and gear-shifting quality deteriorate
Solution Approach 1:
The patent performs preliminary VKP learning and setting actions during the manufacturing process using automated test procedures. The controller executes a series of predetermined test currents and pressure measurements before the transmission is installed in a vehicle, establishing an accurate initial VKP value. This preliminary action ensures high clutch control accuracy from the start while maintaining manufacturing efficiency through automated testing rather than manual adjustment.
Solution Approach 2:
The patent enables the transmission system to perform self-testing and self-calibration during manufacturing. The controller automatically generates test currents, monitors pressure responses, and determines the VKP without requiring external manual intervention or complex adjustment equipment. This self-service capability accelerates the manufacturing process while ensuring precise clutch control reference values are established.
3Reliability
If simple current application methods are used, then the control system is simple, but the VKP detection accuracy and updating speed are insufficient
Solution Approach 1:
The patent employs dynamic control strategies where the controller adjusts current amplitude, frequency, and waveform characteristics based on the learning stage and observed pressure responses. The system transitions from static conventional current application to dynamic adaptive current patterns, including triangular waves with varying parameters and checking currents with different amplitudes. This dynamic approach improves VKP detection reliability while the complexity is managed through software control rather than hardware 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 method enables more precise and rapid learning of the VKP, improving clutch control accuracy and gear-shifting quality in vehicle transmissions.
Implementation Method 1
controlled by hydraulic pressure supplied through a solenoid valve
Implementation Method 2
a plurality of clutch plates and a plurality of clutch discs are alternately arranged to overlap each other between two rotation bodies and are pressed by a piston
Data Source
AI summary
A method of setting a clutch control reference value includes monitoring the pressure of a clutch while a controller applies test current having a predetermined amplitude and frequency to a solenoid valve in the manner of gradually reducing the magnitude of the test current from a predetermined entry value, applying, when the amplitude of the pressure of the clutch starts to change, predetermined checking current, the checking current vertically oscillating based on the magnitude of current when the amplitude of the pressure of the clutch starts to change as a central value, and determining a volumetric kiss point (VKP) by comparing the amplitude of the pressure of the clutch according to application of the checking current with a predetermined reference range.