Hydraulic Oil Temperature Control in Road Finisher Drives
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Solution Overview
Problem
Self-propelled road finishers and feeders face inefficiencies in energy usage due to the low viscosity of hydraulic media at high temperatures, leading to increased pumping losses and reduced energy efficiency, despite powerful hydraulic systems and internal combustion engines.
Innovation Solution
A hydraulic medium operating temperature adjustment and control device is implemented to maintain an optimal temperature range of 60°C to 80°C, independent of the engine cooling system, using a separate cooler and heating device to minimize pumping losses and optimize energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hydraulic medium is cooled to maintain low operating temperature (below 40°C) to avoid overheating and protect seals, then the reliability of the hydraulic system is improved, but the viscosity of the hydraulic medium increases significantly leading to high pumping losses and reduced energy efficiency
Solution Approach 1:
The patent applies dynamics by making the cooling system adjustable rather than fixed. The cooling rate of the hydraulic medium can be dynamically changed based on operating conditions, allowing the system to optimize between reliability and energy efficiency. The control device adjusts cooling intensity to maintain temperature within an optimal range rather than constantly cooling to minimum temperatures.
Solution Approach 2:
The patent changes the temperature parameter of the hydraulic medium from the conventional low temperature range (below 40°C) to an elevated optimal range (60°C to 80°C). This parameter change reduces viscosity and pumping losses while the control device ensures the temperature stays within safe limits to protect seals and maintain reliability.
2Use of energy by moving object
If a powerful internal combustion engine is used to compensate for high pumping losses, then the energy efficiency is maintained, but the fuel consumption increases significantly
Solution Approach 1:
By changing the hydraulic medium temperature parameter to an optimal range (60°C to 80°C), the viscosity is reduced which directly decreases pumping losses. This allows the system to maintain energy efficiency with a less powerful engine, thereby reducing fuel consumption.
Solution Approach 2:
The patent converts the previously harmful high temperature effect (which caused low viscosity but also risked overheating) into a beneficial condition. By carefully controlling the temperature in the 60°C to 80°C range, the system achieves low viscosity for reduced pumping losses while preventing the harmful effects of excessive heat through the adjustable cooling device.
3Power
If the cooling device is controlled based on engine operating temperature, then the engine performance is optimized, but the hydraulic medium is over-cooled causing excessive viscosity increase and energy loss
Solution Approach 1:
The patent segments the control functions by separating the engine cooling control from the hydraulic medium cooling control. The cooling device can independently adjust the cooling rate for the hydraulic medium based on hydraulic system temperature requirements rather than engine temperature, preventing over-cooling and associated energy losses.
Solution Approach 2:
The control device uses feedback from temperature sensors to continuously monitor and adjust the cooling rate of the hydraulic medium. This feedback mechanism ensures the temperature stays within the optimal range (60°C to 80°C), balancing engine performance requirements with hydraulic system efficiency needs.
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 significantly reduces fuel consumption and enhances the operational efficiency of the internal combustion engine and hydrostatic drive units, allowing for a less powerful engine to be used without compromising processing efficiency.
Implementation Method 1
a hydraulic medium cooling area (1c) which is structurally separated from the cooling liquid cooling area (1b)
Implementation Method 2
at least one heating device (20) for the hydraulic circuit (H), in particular for the hydraulic medium reservoir (12)
Data Source
Figure 1~5
Figure 2~3
AI summary
The machine (F) has a setting and regulating device for setting operation temperature of hydraulic medium to about 60[deg] C. The hydraulic medium cooling region includes a cooler having a fan that is switched ON and OFF, while regulating the speed of fan. The hydraulic medium cooler is structurally separated from the cooling liquid cooling region. The fan is connected with the setting and regulating device. A thermostatic valve controlled by the setting and regulating device is arranged in the hydraulic circuit within a bypass deviating from the cooler.