Work Vehicle Fan Control via Variable Relief Valve
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Solution Overview
Problem
Existing work vehicle fan control systems do not effectively manage hydraulic motor rotational speed and fluid flow rates to optimize engine performance and reduce the risk of hydraulic motor damage from low viscosity hydraulic fluid, especially at varying engine speeds and temperatures.
Innovation Solution
A control method that adjusts the current supplied to a solenoid in a variable relief valve to control the flow rate of hydraulic fluid through an oil passage, with specific current magnitudes and flow rates based on engine rotational speed thresholds and temperature, to manage fan rotational speed and reduce hydraulic fluid flow to the hydraulic motor when viscosity is low.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a hydraulic motor is used to rotate the fan at engine start, then the fan can be rotated without engine load, but the hydraulic motor may be damaged by low viscosity hydraulic fluid at low temperatures
Solution Approach 1:
The control device supplies a first current to the solenoid before the engine reaches normal operating conditions to pre-regulate the relief valve, ensuring that hydraulic fluid flow to the hydraulic motor is restricted when fluid viscosity is high due to low temperature, thereby preventing motor damage while enabling fan rotation
Solution Approach 2:
The control device changes the current magnitude supplied to the solenoid based on engine rotational speed thresholds and temperature conditions, dynamically adjusting the relief valve opening degree to optimize hydraulic fluid flow rate and protect the hydraulic motor from low viscosity fluid damage
2Use of energy by moving object
If the fan rotational speed is reduced by controlling hydraulic fluid flow, then power consumption is saved, but the cooling effectiveness may be insufficient at high engine speeds
Solution Approach 1:
The control device dynamically adjusts the second current supplied to the solenoid based on real-time engine rotational speed and temperature sensor readings, continuously optimizing the relief valve opening degree to balance fan power consumption with adequate cooling effectiveness under varying operating conditions
Solution Approach 2:
The control device uses temperature sensor feedback to monitor cooling system performance and adjusts the solenoid current accordingly, ensuring that fan rotational speed is optimized to maintain effective cooling while minimizing power consumption at high engine speeds
3Device complexity
If the relief valve opening degree is fixed, then the control system is simple, but it cannot adapt to varying engine speeds and temperatures
Solution Approach 1:
The control device replaces complex mechanical linkage systems with an electrical control system using a solenoid actuated by variable current from a controller, enabling adaptive adjustment of the relief valve opening degree based on engine rotational speed and temperature sensor inputs while maintaining relatively simple overall system architecture
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 improves power saving and reduces the risk of hydraulic motor damage by optimizing hydraulic fluid flow and managing fan rotational speed according to engine conditions, ensuring efficient operation and longevity of the hydraulic system.
Implementation Method 1
a variable relief valve connected to the oil passage and having a solenoid, the variable relief valve being configured to control the flow rate of the hydraulic fluid flowing through the oil passage in accordance with current flowing to the solenoid
Implementation Method 2
a hydraulic pump to be driven by the engine to supply hydraulic fluid
Implementation Method 3
a hydraulic motor provided in the oil passage to be rotated by the hydraulic fluid, a fan connected to the hydraulic motor to rotate together with the hydraulic motor
Data Source
AI summary
A control method for a fan of a work vehicle includes supplying, when an engine is started, a first current to a solenoid of a variable relief valve such that the hydraulic fluid flows by a first flow rate, supplying, when a rotational speed of the engine becomes larger than a first rotational speed threshold value, a second current larger than the first current to the solenoid such that the hydraulic fluid flows by a second flow rate smaller than the first flow rate to reduce the rotational speed of the fan, and supplying, when the rotational speed of the engine becomes larger than a second rotational speed threshold value that is larger than the first rotational speed threshold value, a current to the solenoid to change the rotational speed of the fan, the current corresponding to a temperature of liquid flowing in the work vehicle.