Linear Solenoid Valve Dither Control Across Oil Temperatures
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Solution Overview
Problem
Existing controllers for linear solenoid valves face challenges in optimizing dither cycle vibrations due to unstable oil temperatures, making it difficult to properly vibrate the spool and maintain hydraulic pressure stability.
Innovation Solution
A controller that executes pulse-width-modulation control and dither control with multiple dither cycles, adjusting the first and second dither cycles based on oil temperature to effectively manage viscosity changes, ensuring proper spool vibration and hydraulic pressure adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single dither cycle is used for dither control, then the control structure is simple, but the spool cannot be properly vibrated when oil temperature varies
Solution Approach 1:
The patent applies dynamics by making the dither cycle variable rather than fixed. The control unit dynamically adjusts the dither cycle based on detected oil temperature, selecting from multiple predetermined dither cycles (first, second, third dither cycles with different lengths). This allows the system to adapt to changing viscosity conditions while maintaining reliable spool vibration across the full temperature range.
2Temperature
If the dither cycle is lengthened for low temperature operation, then the spool can be vibrated properly in high viscosity oil, but the spool cannot be properly vibrated when oil temperature is high
Solution Approach 1:
The patent applies parameter changes by varying the dither cycle length according to oil temperature. The control unit stores multiple predetermined dither cycles with different lengths and selects the appropriate cycle based on the detected temperature. At low temperatures, longer dither cycles are used to overcome high viscosity, while at high temperatures, shorter dither cycles are used for proper spool vibration in low viscosity oil.
3Temperature
If the dither cycle is shortened for high temperature operation, then the spool can be vibrated properly in low viscosity oil, but the spool cannot be properly vibrated when oil temperature is low
Solution Approach 1:
The patent applies parameter changes by varying the dither cycle length according to oil temperature. The control unit stores multiple predetermined dither cycles with different lengths and selects the appropriate cycle based on the detected temperature. At high temperatures, shorter dither cycles are used for proper spool vibration in low viscosity oil, while at low temperatures, longer dither cycles are selected to overcome high viscosity effects.
4Device complexity
If dither control is executed without considering oil temperature, then the control system is simple, but hydraulic pressure stability deteriorates
Solution Approach 1:
The patent applies feedback by using a temperature detection unit to monitor oil temperature and feeding this information back to the control unit. The control unit then selects the appropriate dither cycle from multiple predetermined cycles based on the detected temperature, ensuring stable hydraulic pressure control across varying temperature conditions while maintaining reasonable system 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
The controller ensures stable spool vibration and hydraulic pressure control across varying oil temperatures by dynamically adjusting dither cycles, improving controllability and responsiveness of the linear solenoid valve.
Implementation Method 1
a electromagnet 33 that moves the spool 32 in the axial direction
Implementation Method 2
a spring 34 that biases the spool 32 toward one side in the axial direction
Implementation Method 3
a dither control that cyclically increases and decreases an exciting current so as to vibrate a spool of the linear solenoid valve
Implementation Method 4
to reduce the static friction between a sleeve and a spool of a linear solenoid valve
Data Source
AI summary
A controller executes a dither control that cyclically increases and decreases an exciting current in a linear solenoid valve so as to vibrate a spool of the linear solenoid valve. A vibration cycle of the spool obtained through the dither control is referred to a dither cycle. The dither control includes a first dither control that vibrates the spool in a first dither cycle and a second dither control that vibrates the spool in a second dither cycle that is shorter than the first dither cycle. The controller executes the first dither control and the second dither control when an oil temperature of the hydraulic oil is between a first oil temperature and a second oil temperature that is higher than the first oil temperature.