Wheel Loader Cooling Fan Control for Rapid Cab Temperature Pull-Down
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Solution Overview
Problem
Existing construction machine cooling systems fail to stably cool the cab interior, particularly when the operator requests rapid temperature reduction, due to limitations in fan rotation based on radiator and oil temperatures without considering the air conditioner's operation status.
Innovation Solution
A construction machine equipped with a cab, air conditioning unit, cooling fan, temperature setting section, room temperature sensor, and controller that adjusts the cooling fan's rotation to maintain a predetermined level when the cab temperature exceeds the set temperature, ensuring efficient cooling and heating by optimizing the refrigerant's circulation and fan operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fan rotation amount is limited based on radiator and oil temperatures, then the cooling system operates efficiently under normal conditions, but the cab interior cannot be rapidly cooled when the air conditioner is activated
Solution Approach 1:
The fan rotation control is made dynamic by introducing multiple control modes (first control mode for normal operation, second control mode for rapid cooling) that switch based on air conditioner operation status. This allows the system to adapt fan rotation requirements to different operational contexts, enabling rapid cooling when needed while maintaining energy efficiency during normal operation.
Solution Approach 2:
The control system changes the parameter of fan rotation amount based on the operational state of the air conditioner. When the air conditioner is activated and cab temperature exceeds the set temperature, the system increases fan rotation to a higher level than the normal temperature-based control would permit, thereby enabling rapid cooling without permanently compromising energy efficiency.
2Productivity
If the fan rotation amount is increased to rapidly cool the cab, then cooling efficiency improves, but the cooling capacity for radiator and oil cooler is reduced
Solution Approach 1:
The system dynamically switches between control modes based on priority needs. The second control mode temporarily prioritizes cab cooling by increasing fan rotation, while the first control mode maintains balanced cooling for all components. This dynamic adjustment allows rapid cab cooling without permanently sacrificing the cooling capacity of other components.
Solution Approach 2:
The control system periodically evaluates the operational state of the air conditioner and adjusts fan rotation accordingly. When rapid cooling is needed, the system activates the second control mode temporarily; when normal operation suffices, it returns to the first control mode, creating a periodic adjustment pattern that balances competing cooling demands.
3Ease of operation
If the fan rotation is controlled solely by temperature sensors, then the control system remains simple, but it cannot respond to operator requests for rapid cooling
Solution Approach 1:
The control system achieves multi-functionality by integrating both automatic temperature-based control and manual operator-requested rapid cooling control into a single unified system. The controller can operate in either the first control mode (automatic) or the second control mode (rapid cooling), providing both automated efficiency and operator control without requiring separate systems.
Solution Approach 2:
The control system incorporates feedback from the air conditioner operation status and cab temperature to automatically determine when to activate rapid cooling mode. This feedback mechanism allows the system to respond to operator needs (when AC is on and temperature exceeds set point) without requiring direct manual input, maintaining ease of operation while enabling rapid cooling when needed.
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 solution enables stable and rapid cooling of the cab interior according to operator requests by maintaining the cooling efficiency of the refrigerant and achieving maximum heating effects, while also effectively cooling radiators, torque converter oil coolers, and operating oil coolers.
Implementation Method 1
The cooling fan cools the capacitor
Implementation Method 2
a compressor which is connected to the capacitor
Implementation Method 3
an evaporator which is connected to the capacitor and the compressor, a blower fan which blows a wind to the evaporator
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A wheel loader (1) is provided with a cab (5), an air conditioning unit (60), a cooling fan (46) which has a capacitor (43) and a compressor (64), an air conditioning switch (83) which receives the operation or non-operation of the compressor (64), a temperature setting portion (82) which sets a set temperature inside the cab (5), a room temperature sensor (90) which detects a room temperature inside the cab (5), and a controller (70). In a case where the air conditioning switch (83) is operated and the room temperature is higher than a set temperature, the controller (70) adjusts so that the rotation amount of the cooling fan (46) is maintained at a limited rotation amount (RLMT) or more.