Valve Configuration Dither-Modulation for Hysteresis Reduction
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Solution Overview
Problem
The increasing demand for high torque transmission in vehicles with electro-hydraulic steering and automatic transmissions leads to increased manufacturing and operational efforts due to friction and hysteresis issues in electro-hydraulic actuators, resulting in higher costs and reduced durability.
Innovation Solution
A valve configuration system using pulse-width modulation with Dither-Modulation activated only under specific operating conditions to reduce hysteresis and friction, optimizing pressure accuracy and minimizing wear by adjusting the amplitude and frequency of the Dither-Signal based on pre-defined parameters such as temperature, torque, and gear ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Dither-Modulation is continuously applied to reduce hysteresis and improve precision, then measurement precision and reliability improve, but device complexity and energy consumption increase
Solution Approach 1:
The patent applies conditional Dither-Modulation that dynamically activates and deactivates based on operating conditions. The control unit monitors parameters such as torque demand, gear position, and temperature, and only applies Dither-Modulation when precision requirements exceed a threshold or when operating conditions indicate benefit, thereby reducing unnecessary control complexity while maintaining precision when needed
Solution Approach 2:
The patent changes the operational parameters of the Dither-Modulation based on system state. By adjusting the modulation amplitude, frequency, or activation status according to torque demand, temperature, and gear position, the system optimizes precision performance while avoiding constant application that would increase control complexity and energy consumption
2Reliability
If Dither-Modulation is applied to reduce friction and hysteresis, then reliability and precision improve, but wear increases reducing duration of action
Solution Approach 1:
The patent implements periodic Dither-Modulation activated only during specific operating conditions such as gear shifts, torque transitions, or temperature variations. By applying the modulation periodically rather than continuously, the system maintains reliability during critical operations while significantly reducing cumulative wear and extending valve durability
Solution Approach 2:
The patent applies Dither-Modulation partially, only when and where it provides necessary benefit for reliability. By monitoring operating conditions and activating modulation only during critical phases (such as gear changes or high-torque conditions), the system achieves sufficient reliability without the excessive continuous application that would cause accelerated wear
3Measurement precision
If manufacturing tolerances are tightened to improve actuator precision, then measurement precision improves, but ease of manufacture deteriorates
Solution Approach 1:
The patent replaces mechanical precision requirements with an electronic control solution. By using Dither-Modulation and adaptive control algorithms, the system compensates for manufacturing tolerances in the valve and actuator components, achieving high measurement precision without requiring costly tight manufacturing tolerances
Solution Approach 2:
The patent implements a self-compensating control system that automatically adjusts for manufacturing variations. The control unit monitors system performance and dynamically adjusts Dither-Modulation parameters to compensate for individual component tolerances, allowing standard manufacturing tolerances to achieve the required precision performance
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 reduces hysteresis and friction in the valve system, enhancing precision and durability while minimizing wear, thus improving driving comfort and reducing operational costs by applying Dither-Modulation only when necessary.
Implementation Method 1
an electro-mechanical actuator which operates the valve unit
Implementation Method 2
The actuator anchor and the electro-mechanical parts of the actuator, physically connected to the valve gate, are undergoing a vibration
Implementation Method 3
The vibration causes a reduction of the friction in the valve, and, therefore, a reduction of the hysteresis
Implementation Method 4
through the valve unit, the actuator and a related pulse-width modulated signal at the actuator will produce an adjustable hydraulic pressure value
Data Source
AI summary
A method of operating a valve system of a transmission comprising part of the vehicle drive train through a valve unit and said valve unit's electro-magnetic activator configuration. In a transmission's hydraulic system and is part of the vehicle drive train, its hydraulic pressure value (p_EDS) can be employed and adjusted through a valve unit configuration by applying a pulse-width-modulated current signal (i_EDS) to the electro-magnetic activator system. The pulse-width modulated current signal (i_EDS) and its amplitude (A) and/or its pulse duration (pw1) will periodically change, during the applied Dither-Modulation, by maintaining the required pressure value (p_EDS) at the same time, whereby a lengthwise movable anchor, which is attached a valve shaft of the valve system, receives hereby an imposed vibrating oscillation. According to the invention, the Dither-Modulation is activated or deactivated during pre-defined operating conditions of the vehicle drive train.