Hydraulic Fan Drive Control for Overspeed and Pressure Loss
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Solution Overview
Problem
Hydraulic fan systems in work machines suffer from inefficient speed control, leading to potential damage due to overspeeding and lack of operational monitoring, with existing solutions causing efficiency losses and safety hazards.
Innovation Solution
A method and system for controlling hydraulic fan speed independently of fluid flow, using a hydraulic variable displacement pump with an adjustable tilt angle, combined with a control unit and shutdown valve, to maintain stable operation and prevent overspeeding, and provide real-time monitoring and notification of system conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic orifices or valves are arranged in the hydraulic circuit to reduce motor inlet pressure and prevent fan overspeed, then fan safety is improved, but hydraulic efficiency deteriorates due to pressure losses
Solution Approach 1:
The patent replaces the mechanical hydraulic pressure control system (orifices and valves) with an electronic control system that monitors hydraulic parameters and actively adjusts pump displacement. This substitution eliminates the inherent pressure losses of passive hydraulic restriction elements while maintaining fan speed protection through electronic monitoring and active pump control.
Solution Approach 2:
The patent implements a feedback control system that continuously monitors hydraulic pressure, flow rate, and fan speed, then adjusts the variable displacement pump to maintain optimal operating conditions. This closed-loop feedback eliminates the need for passive pressure-reducing orifices and valves, thereby preventing energy losses while ensuring fan safety.
2Ease of operation
If traditional hydraulic control means are used to control fan speed, then fan speed control is achieved, but control precision and efficiency deteriorate
Solution Approach 1:
The patent replaces traditional mechanical hydraulic control means with an electronic control system that uses sensors and electronic actuators. This substitution enables precise measurement of hydraulic parameters and accurate control of pump displacement, thereby achieving superior control precision and efficiency compared to mechanical systems.
Solution Approach 2:
The patent utilizes a variable displacement pump whose displacement can be continuously adjusted by changing the tilt angle of its swashplate through electronic control. This parameter change capability allows precise control of hydraulic flow rate and consequently fan speed, overcoming the limited control options of traditional fixed-displacement hydraulic systems.
3Adaptability or versatility
If pressure control is used in hydraulic fan systems, then load-dependent operation is achieved, but fan speed stability deteriorates when suction fan or grill is blocked
Solution Approach 1:
The patent implements feedback control that monitors both pressure and flow rate parameters, allowing the system to distinguish between normal load variations and abnormal conditions such as grill blockage. When blockage is detected, the system can maintain stable fan speed by adjusting pump displacement, preventing the runaway speed increase that occurs in pure pressure-controlled systems.
Solution Approach 2:
The patent creates a control system that performs multiple functions: it provides load-dependent operation like traditional pressure control, but also detects abnormal conditions (grill blockage, fan overspeed risk) and actively stabilizes fan speed. This multi-functionality resolves the contradiction by maintaining adaptability while adding stability under abnormal conditions.
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
Enhances system efficiency by reducing hydraulic losses and preventing damage, while enabling real-time monitoring and proactive safety measures to address potential hazards.
Implementation Method 1
a hydraulic pump (10) with variable displacement... The pump outlet (16) is connected via a shutdown valve (30) to an inlet line (22) of the hydraulic motor (20)
Implementation Method 2
The hydraulic motor (20) is connected via a motor outlet line (24) to a hydraulic tank (5)... drives a fan (25)
Data Source
AI summary
The fan system includes a fan operated by a hydraulic motor which is driven by a hydraulic variable displacement pump that includes 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 includes means for determining the volumetric flow rate of the pump and a control unit having: 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, wherein an ideal tilt current value is derived from the calculated fan speed and safety actions are performed in order to prevent damage to the fan, if the difference between the ideal tilt current value and the adapted tilt current is higher than a tilt current threshold value.