Hydraulic Fan Speed Control With Variable Pump Feedback
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Solution Overview
Problem
Hydraulic fan systems face inefficiencies due to pressure-controlled speed control, leading to potential overspeed and damage, and lack of operational monitoring, making it difficult for operators to identify hazards like fan grill blockages.
Innovation Solution
A hydraulic fan system with a variable displacement pump driven by an electronic displacement control unit, allowing independent control of fan speed from fluid flow, and incorporating a control unit that measures operational parameters, calculates fan speed, and adjusts tilt current to maintain stable operation, while detecting potential hazards and initiating safety actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If pressure-controlled hydraulic means are used to control fan speed, then fan speed control is provided, but fan efficiency decreases and hydraulic losses increase
Solution Approach 1:
The patent replaces the traditional pressure-controlled hydraulic system with an electronically controlled system. A control unit receives signals from a sensor detecting fan speed and generates control signals to adjust the tilt angle of the swashplate, thereby controlling hydraulic motor speed and fan speed independently of hydraulic pressure, eliminating the need for pressure-controlled hydraulic means and reducing hydraulic losses
Solution Approach 2:
The patent changes the control parameter from hydraulic pressure to electronic signals based on actual fan speed feedback. The control unit adjusts the tilt angle parameter of the swashplate based on detected fan speed, enabling direct speed control rather than indirect pressure-based control, which improves efficiency by eliminating unnecessary pressure control mechanisms
2Reliability
If hydraulic orifices or valves are arranged to reduce motor inlet pressure, then fan overspeed is prevented, but efficiency losses occur
Solution Approach 1:
The patent replaces mechanical pressure-reducing orifices and valves with an electronic control system that directly regulates hydraulic motor speed. The control unit adjusts the swashplate tilt angle based on fan speed feedback, preventing overspeed through active electronic control rather than passive pressure reduction, thereby maintaining efficiency while ensuring safety
Solution Approach 2:
The patent implements a feedback control system where a sensor detects actual fan speed and sends signals to the control unit, which adjusts the hydraulic motor operation accordingly. This closed-loop feedback prevents fan overspeed by continuously monitoring and adjusting speed, replacing the open-loop pressure-reducing mechanism with an intelligent responsive system that maintains efficiency
3Speed
If traditional hydraulic control systems are used, then fan speed control is provided, but operational state monitoring is not available
Solution Approach 1:
The patent makes the control unit multi-functional by enabling it to not only control fan speed through tilt angle adjustment but also to receive signals from sensors, detect operational states, store information in memory, and generate warnings. This single control unit performs both control and monitoring functions, eliminating the need for separate monitoring systems and providing comprehensive operational state information
Solution Approach 2:
The patent implements comprehensive feedback by using sensors to detect operational parameters and feeding this information back to the control unit. The control unit processes this feedback information, stores it in memory, and can generate warnings, providing the operator with real-time operational state information while maintaining speed control functionality
Data Source
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AI summary
Hydraulic fan system and method for controlling the speed of a hydraulic fan system. The fan system comprises a fan operated by a hydraulic motor which is driven by a hydraulic variable displacement pump comprising a displacement volume adjusting element. A tilt angle of the displacement volume adjusting element can be adjusted by controlling a tilt current supplied to an electronic displacement control unit. The hydraulic fan system further comprises means for determining the volumetric flow rate of the pump and a control unit comprising: a signal connection to the means for determining the volumetric flow rate of the pump, a signal connection to a fan speed setting device, and a fan speed calculating unit for calculating a fan speed from the determined volumetric flow rate, a fan speed error determining unit for determining a fan speed error by comparing the calculated fan speed to the fan speed set by the fan speed setting device. The control unit can supply an adapted tilt current to the electronic displacement control unit in order to adjust the tilt angle of the displacement volume adjusting device, such that the volumetric flow rate can be adapted in order to reduce the fan speed error.