Cooling Fan Control for Rapid Wheel Loader Cab Cooling
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Solution Overview
Problem
Existing construction machine cooling systems fail to stably cool the cab interior, especially when the operator requests rapid temperature reduction, due to limitations in fan rotational speed based on radiator and oil temperatures without considering the air conditioner's operation status.
Innovation Solution
A construction machine equipped with a cooling fan control system that includes a controller, air conditioning unit, temperature sensor, and hydraulic pump, which adjusts the fan's rotational speed based on cab temperature and air conditioning switch operation to maintain cooling efficiency and allow rapid temperature changes, and adjusts the hydraulic pump's capacity to optimize heating and cooling effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotational speed of the cooling fan is limited based on radiator and oil temperatures, then energy consumption is reduced and system stability is improved, but the cooling speed of the cab interior becomes insufficient when rapid temperature reduction is needed
Solution Approach 1:
The cooling fan rotational speed is made dynamically adjustable based on different operating conditions. The control unit increases fan speed when the air conditioner operates in cooling mode and the cab temperature exceeds the set temperature, while maintaining lower speeds during heating mode or normal temperature conditions. This dynamic adjustment resolves the contradiction by allowing high cooling speed when needed while maintaining system stability during normal operation.
Solution Approach 2:
The system changes the operational parameters of the cooling fan based on the air conditioner's operating mode. When cooling mode is activated, the fan speed parameter is increased to enhance heat dissipation from the condenser, thereby improving cab cooling efficiency. This parameter change allows the system to achieve rapid cooling when required while maintaining energy efficiency during heating or stable temperature conditions.
2Productivity
If the fan rotational speed is increased to improve cooling effect, then cab cooling performance is enhanced, but energy consumption increases
Solution Approach 1:
The cooling fan speed is dynamically adjusted based on actual cooling demand. The control unit monitors cab temperature and air conditioner mode, increasing fan speed only when cooling mode is active and cab temperature exceeds the set temperature. During heating mode or when temperature is within acceptable range, fan speed is reduced. This dynamic adjustment enhances cooling performance when needed while minimizing energy consumption during normal operation.
Solution Approach 2:
The system changes the fan speed parameter based on operational conditions. High fan speed is applied only during cooling mode when cab temperature exceeds the set temperature, maximizing cooling effect. During heating mode or stable temperature conditions, fan speed is reduced to minimize energy consumption. This conditional parameter change resolves the contradiction between cooling effectiveness and energy efficiency.
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 enables stable and rapid cooling of the cab interior by maintaining minimum cooling efficiency when needed and maximizing heating efficiency, effectively addressing the limitations of previous systems by ensuring consistent temperature control.
Implementation Method 1
a cooling fan 46 which cools the condenser 43
Implementation Method 2
a radiator for cooling the refrigerant which circulates in an engine
Implementation Method 3
an evaporator which is connected to the condenser and the compressor
Implementation Method 4
The hydraulic pump has a swash plate for adjusting the amount of oil which is sent to the cooling fan
Data Source
AI summary
A wheel loader is provided with a cab, an air conditioning unit, a cooling fan which has a condenser and a compressor, an air conditioning switch which receives the operation or non-operation of the compressor, a temperature setting portion which sets a set temperature inside the cab, a room temperature sensor which detects a room temperature inside the cab, and a controller. In a case where the air conditioning switch is operated and the room temperature is higher than a set temperature, the controller maintains the rotation amount of the cooling fan at a limited rotation amount or more.