Cooling Fan Speed Control for Working Machine Horsepower Allocation
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Solution Overview
Problem
In heavy-duty work, the horsepower consumed by the cooling system of a working machine reduces the available horsepower for the working device and traveling device, leading to decreased workability due to a large load on the prime mover.
Innovation Solution
A working machine with a controller that performs reduction and restoration control of the cooling fan's rotation speed based on the prime mover's speed, adjusting the target fan rotation speed to optimize horsepower allocation and improve workability, while also considering temperature measurements to manage cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cooling fan rotation speed is maintained at a high level to ensure adequate cooling, then the cooling performance is improved, but the horsepower consumed by the cooling system increases, reducing the available horsepower for working operations
Solution Approach 1:
The patent implements dynamic adjustment of the cooling fan rotation speed based on real-time monitoring of prime mover rotation speed and load conditions. The controller dynamically modifies the target fan rotation speed according to actual operating conditions, transitioning from a static high-speed operation to a dynamic adaptive speed control system that optimizes the balance between cooling performance and power availability for work operations.
Solution Approach 2:
The patent changes the operational parameters of the cooling fan by adjusting its rotation speed based on prime mover load conditions. When the prime mover rotation speed decreases indicating heavy load, the system reduces the target fan rotation speed parameter, thereby reducing cooling power consumption and increasing available horsepower for working operations while maintaining adequate cooling when conditions permit.
2Power
If the cooling fan rotation speed is reduced to save horsepower during heavy-duty work, then the available horsepower for working operations increases, but the cooling performance may deteriorate
Solution Approach 1:
The patent implements a feedback control mechanism where the controller continuously monitors the prime mover rotation speed and uses this information to adjust the target cooling fan rotation speed. This closed-loop feedback system ensures that cooling fan speed is reduced only when appropriate (when prime mover speed indicates heavy load) and maintains or restores cooling performance when the prime mover operates at higher speeds, thereby balancing power availability with cooling requirements.
Solution Approach 2:
The patent performs preliminary action by setting a target fan rotation speed that is adjusted in advance based on prime mover rotation speed trends. The controller proactively modifies the cooling fan speed target before the cooling demand becomes critical, using the prime mover speed as an early indicator of load conditions, thus preventing both excessive power consumption and inadequate cooling.
3Power
If the target fan rotation speed is adjusted dynamically based on prime mover speed, then the horsepower allocation is optimized, but the control system complexity increases
Solution Approach 1:
The patent replaces complex mechanical speed control mechanisms with an electronic control system that uses sensors and a controller to monitor prime mover rotation speed and adjust the cooling fan target speed accordingly. This substitution of mechanical systems with electronic control simplifies the overall system architecture while achieving dynamic optimization of horsepower allocation between the cooling system and working operations.
Data Source
AI summary
A working machine includes a prime mover, a hydraulic pump driven by power of the prime mover, a cooler including a cooling fan rotated by either the power of the prime mover or hydraulic fluid delivered from the hydraulic pump, and a controller configured or programmed to perform a reduction control for reducing a target fan rotation speed that is a target rotation speed of the cooling fan in response to reduction of an actual prime mover rotation speed that is an actual rotation speed of the prime mover, and to perform, after the reduction control, a restoration control for restoring the target fan rotation speed. The controller is configured or programmed to make a difference between a reduction rate of the target fan rotation speed in the reduction control and an increase rate of the target fan rotation speed in the restoration control.