Variable Speed Cooling Fan for Construction Machines
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Solution Overview
Problem
Existing cooling systems in construction machines, such as hydraulic excavators, face challenges in reducing noise and ensuring a required cooling air flow rate, particularly when using a hydraulically driven cooling fan that is not adequately controlled for the intercooler, radiator, and oil cooler.
Innovation Solution
A cooling system that includes an intercooler, radiator, oil cooler, and condenser, driven by a fan hydraulic motor and pump, with temperature sensors and control means to adjust the cooling fan rotation speed based on detected temperatures and air conditions, ensuring the maximum required flow rate is maintained while minimizing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cooling fan directly driven by the engine is used, then the cooling fan rotation speed is proportional to engine revolution speed, but the cooling water and working oil are overcooled and warm-up operation time increases
Solution Approach 1:
The patent applies dynamics by making the cooling fan rotation speed variable rather than fixed. The fan speed is dynamically adjusted based on real-time temperature conditions (cooling water temperature, working oil temperature) and engine revolution speed, allowing the system to adapt to varying operational requirements and prevent both overcooling and insufficient cooling scenarios
Solution Approach 2:
The patent changes the parameter of fan rotation speed from a fixed proportional relationship with engine speed to a controlled variable parameter. By using a fan hydraulic motor with variable displacement pump, the system can independently control fan speed parameters based on multiple sensed conditions, optimizing cooling efficiency while preventing excessive cooling during warm-up phases
2Power
If a hydraulically driven cooling fan is used to forcibly cool the radiator and oil cooler, then cooling capability is improved, but the rotation speed is not adequately controlled for the intercooler resulting in insufficient cooling air flow rate
Solution Approach 1:
The patent applies universality by designing a single cooling fan system that serves multiple heat exchangers simultaneously - the intercooler, radiator, and oil cooler. The fan hydraulic motor and variable displacement pump create a unified controlled cooling system that can distribute cooling air to all components based on their respective temperature conditions, ensuring comprehensive and reliable cooling coverage
Solution Approach 2:
The patent implements feedback control by using temperature sensors on the cooling water, working oil, and intercooler air outlet, along with an engine revolution speed sensor. The controller continuously receives this feedback information and adjusts the fan hydraulic pump delivery displacement accordingly, ensuring the cooling air flow rate meets the required standards for all heat exchangers under varying operational conditions
3Reliability
If the cooling fan rotation speed is increased to ensure cooling air flow rate, then cooling performance is improved, but noise increases
Solution Approach 1:
The patent applies dynamics by making the fan rotation speed variable and adaptive rather than fixed or constantly high. The system dynamically adjusts fan speed based on actual cooling requirements determined by temperature sensors and engine conditions, maintaining sufficient cooling air flow rate only when necessary and reducing speed when cooling demand is low, thereby minimizing noise generation while ensuring cooling reliability
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
The system effectively reduces noise and ensures reliable cooling air flow rates for the intercooler, radiator, and oil cooler, preventing unnecessary increases in cooling fan speed and maintaining optimal performance across varying conditions.
Implementation Method 1
a cooling fan for producing cooling air introduced to the intercooler, the radiator and the oil cooler
Implementation Method 2
an intercooler for cooling compressed air pressurized by a turbo charger
Implementation Method 3
a radiator for cooling engine cooling water
Implementation Method 4
an oil cooler for cooling working oil in a hydraulic driving system
Data Source
AI summary
A cooling system for a construction machine, which can reduce noise of a cooling fan and can reliably produce cooling air at a required flow rate.The cooling system comprises a cooling fan 25 for producing cooling air introduced to an intercooler 22, a radiator 23 and an oil cooler 24, a fan hydraulic motor 26 for driving the cooling fan 25, a fan hydraulic pump 27 for delivering a hydraulic fluid to the fan hydraulic motor 26, an air temperature sensor 31 for detecting an air temperature T1 at an outlet of the intercooler 22, a cooling water temperature sensor 33 for detecting a temperature T2 of cooling water for the radiator 23, a working oil temperature sensor 36 for detecting a temperature T3 of working oil for the oil cooler 24, and a controller 29 for outputting a control signal corresponding to a maximum value among calculation values N1, N2 and N3 of cooling fan rotation speed, which correspond respectively to detected values T1, T2 and T3 from the air temperature sensor 31, the cooling water temperature sensor 33 and the working oil temperature sensor 36.