Cooling Fan Drive System Engine Load Management
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Solution Overview
Problem
Existing cooling fan drive systems for travel type working machines increase engine load and reduce travel acceleration performance when temperatures are high, leading to poor exhaust gas quality and environmental pollution.
Innovation Solution
A cooling fan drive system that includes temperature and rotational speed detecting means, with a control mechanism to optimize cooling fan rotational speed based on engine cooling water temperature and restrict speed increases during engine acceleration, using a variable displacement hydraulic pump and motor to manage delivery pressure and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the tilting angle or displacement volume of the hydraulic pump is controlled to a large value to increase cooling fan rotational speed when temperatures are high, then the cooling fan can provide adequate cooling, but the engine load increases and travel acceleration performance deteriorates
Solution Approach 1:
The system dynamically adjusts the priority between cooling and acceleration based on real-time operating conditions. During normal high-temperature operation, the hydraulic pump tilting angle is increased to boost cooling fan speed. However, during detected acceleration requests, the system temporarily reduces the tilting angle to minimize engine load, then restores it after acceleration completes, ensuring both cooling needs and acceleration performance are met.
Solution Approach 2:
The system changes the operational parameters of the hydraulic pump (tilting angle and displacement volume) based on detected conditions. When acceleration is detected, the tilting angle is reduced from its high-temperature setting to a lower value, temporarily sacrificing cooling capacity to enable smooth acceleration. After acceleration, the parameter is restored to maintain cooling effectiveness.
2Temperature
If the cooling fan rotational speed is increased to cool the engine when temperatures are high, then the engine cooling effectiveness improves, but the engine load increases and exhaust gas quality deteriorates
Solution Approach 1:
The system dynamically modulates the hydraulic pump tilting angle based on acceleration detection. During acceleration events, the tilting angle is temporarily reduced to decrease the driving pressure required by the hydraulic motor, thereby reducing engine load and improving exhaust gas quality. When acceleration is complete, the tilting angle is restored to maintain adequate cooling fan speed for temperature control.
Solution Approach 2:
The system applies preliminary anti-action by detecting acceleration requests before they fully manifest and preemptively reducing the hydraulic pump tilting angle. This prevents the exacerbation of engine load during acceleration, thereby proactively maintaining better exhaust gas quality while still ensuring cooling needs are met after acceleration completes.
3Temperature
If the delivery capacity of the hydraulic pump is increased to drive the cooling fan at high speed, then the cooling performance improves, but the driving pressure increases and engine load worsens
Solution Approach 1:
The system dynamically adjusts the hydraulic pump tilting angle based on real-time acceleration detection. During acceleration, the tilting angle is reduced to lower the delivery pressure and engine load, even if this temporarily reduces cooling fan speed. After acceleration, the tilting angle is restored to maintain cooling performance, creating a time-varying control strategy that balances competing demands.
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 ensures optimal cooling fan speed control, reducing engine load and enhancing travel acceleration performance while minimizing exhaust gas deterioration and environmental impact.
Implementation Method 1
a hydraulic pump driven by an engine... delivering a hydraulic fluid
Implementation Method 2
a hydraulic motor actuated by a hydraulic fluid delivered by the hydraulic pump for rotating the cooling fan
Implementation Method 3
The radiator and the oil cooler are cooled by air produced by a cooling fan
Data Source
Figure 1
Figure 2
Figure 3
AI summary
It is provided a cooling fan drive device system (21; 21A; 21B) for a travel type working machine including a cooling fan (9) for cooling an engine cooling water, a hydraulic pump (22; 22A) driven by an engine (1), a hydraulic motor (23; 23A) actuated by a hydraulic fluid delivered by the hydraulic pump for rotating the cooling fan, and temperature detecting means (31) for detecting the temperature of the engine cooling water, wherein said cooling fan drive system comprises: rotational speed detecting means (34) for detecting the rotational speed of the engine; and cooling fan control means (24, 35a, 35b, 35c, 35d, 35e, 35f, 35g, 35h; 24, 35a, 35b, 35c, 35d, 35f, 35g, 35h, 35i; 44, 35a, 35b, 35c, 35d, 35e, 35f, 35h, 35j; 54, 35a, 35b, 35c, 35d, 35e, 35f, 35h, 35k) for controlling the rotational speed of the hydraulic motor on the basis of the detection values of the temperature detecting means and the rotational speed detecting means so that the rotational speed of the cooling fan is increased as the temperature of the engine cooling water rises up and the increase of the rotational speed of the cooling fan is limited when the rotational speed of the engine increases. It is an object of the present invention to provide a cooling fan drive device system with an improved functionality. Therefore the rotational speed detecting means (34) has means (34) for detecting the target rotational speed of the engine (1) and means (34) for detecting the actual rotational speed of the engine, and the cooling fan control means (24; 35a, 35b, 35c, 35d, 35f, 35g, 35h, 35i) calculates the fan target rotational speed that increases as the temperature of the engine cooling water rises up, calculates the limiting value of the fan target rotational speed that is lowered as the rotational speed difference between the target rotational speed and the actual rotational speed of the engine increases, corrects the fan target rotational speed so that the fan target rotational speed does not exceed the limiting value, and controls the rotational speed of the hydraulic motor (23) so as to achieve the corrected fan target rotational speed.