Adaptive Flow Control Solenoid Valve Compensation
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Solution Overview
Problem
Existing flow control solenoid valves in hydraulic systems face challenges in adapting to changes due to age, wear, and temperature variations, leading to inconsistencies in fluid flow and clutch performance, which affect shift quality and durability.
Innovation Solution
A controller learns the actual flow characteristics of the valve over time by updating lookup tables with commanded and actual flow rates at different temperatures, calculating a compensation scale factor to adjust flow control signals, ensuring accurate fluid flow and improving clutch performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flow control solenoid valve is used in a hydraulic system, then fluid flow control is achieved, but the valve performance deteriorates over time due to age, wear, and temperature variations
Solution Approach 1:
The controller continuously monitors the actual flow rate through the valve by measuring clutch position and compares it with the commanded flow rate. This feedback loop enables the system to detect deviations caused by valve wear or temperature changes and automatically compensate by adjusting the flow control commands, thereby maintaining reliable performance throughout the valve's service life.
Solution Approach 2:
The system adapts to changing valve characteristics by modifying control parameters (flow control commands) based on learned actual flow characteristics. The controller updates lookup tables with compensation scale factors that adjust the commanded flow rates to account for valve degradation or temperature effects, ensuring consistent performance over time.
2Measurement precision
If generic flow vs. current characteristic tables are used for valve control, then initial flow control accuracy is achieved, but inaccuracies develop due to differences between generic data and actual valve performance
Solution Approach 1:
The controller performs preliminary learning of the actual valve characteristics during initial operation or calibration phases. By measuring the relationship between commanded and actual flow rates under various conditions, the system builds customized lookup tables specific to that valve instance, eliminating the need to rely on generic manufacturer data and ensuring high accuracy from the start.
Solution Approach 2:
The system automatically characterizes its own valve by monitoring actual flow rates and generating customized compensation tables without requiring external calibration equipment or manual intervention. This self-learning capability enables the controller to adapt to the specific valve's characteristics and maintain accurate flow control throughout its operational life.
3Device complexity
If temperature variations are not compensated, then system simplicity is maintained, but fluid flow consistency deteriorates due to changes in oil viscosity and temperature-dependent factors
Solution Approach 1:
The controller monitors clutch position to infer actual flow rate and compares it with commanded values, detecting temperature-induced flow deviations. By using this feedback to update compensation tables, the system automatically adapts to temperature variations without adding complex temperature sensors or separate thermal management systems.
Solution Approach 2:
The existing position sensor and controller are used for multiple purposes: clutch position control, actual flow rate measurement, and temperature compensation. This multi-functionality allows the system to maintain fluid flow consistency across temperature variations without increasing device complexity, as the same hardware components serve multiple control functions.
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 adaptive methodology enhances shift feel and clutch durability by accounting for variations in valve performance, resulting in more predictable and accurate fluid flow control.
Implementation Method 1
a flow control solenoid valve that opens in response to flow control signals... electrical current commands required for energizing windings of the solenoid portion of the valve
Data Source
AI summary
A vehicle includes an engine, first clutch, transmission, and controller. The transmission includes a gearbox, position sensors, and a fluid circuit. The gearbox contains a second clutch. The fluid circuit includes a pump and a flow control solenoid valve. The controller opens the valve via flow control signals to allow fluid to pass into or from the particular clutch it feeds. The controller executes steps of a method to determine an actual flow rate through the valve as the clutch moves, and also calculates a compensation scale factor as a ratio of the commanded and actual flow rates. The controller modifies the flow control signals in a subsequent clutch actuation using the compensation scale factor, such as by multiplying a commanded flow rate corresponding to the flow control signals by the compensation scale factor. A system includes rotatable members connected by a clutch, the controller, valve, and position sensor.