Construction Machine Hydraulic Circuit for Cold-Weather Battery Heating
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Solution Overview
Problem
In cold climates, the performance of batteries in construction machines using electric motors deteriorates due to low temperatures.
Innovation Solution
A hydraulic system with a heat exchanger that performs heat exchange between cooling water and hydraulic oil, and a circulation pump that circulates cooling water through a battery and a radiator, along with switching valves to control the flow of hydraulic oil and cooling water, is implemented to increase battery temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an electric motor is adopted instead of an engine, then environmental performance is improved, but battery performance deteriorates in cold climates
Solution Approach 1:
The patent converts the harmful effect of cold temperatures on battery performance into a beneficial heating system. The heat exchanger normally used for cooling the hydraulic oil is repurposed to heat the battery by circulating cooled hydraulic oil through the battery during cold conditions, thus converting a potential harm (cold weather) into a benefit (battery warming) using existing system components.
Solution Approach 2:
The heat exchanger and circulation system are designed to perform multiple functions: cooling the hydraulic oil during normal operation and heating the battery during cold conditions. The switching valve enables the system to alternate between these two functions based on operational requirements, making the thermal management system universal rather than dedicated to a single function.
2Temperature
If a heat exchanger is added to heat the battery, then battery temperature is improved, but system complexity increases
Solution Approach 1:
The patent merges the battery heating function with the existing hydraulic oil cooling system by integrating a heat exchanger that serves both purposes. The circulation pump and switching valve are added to enable the hydraulic oil to transfer heat to the battery when needed, combining two thermal management functions into a single integrated system rather than creating separate independent systems.
Solution Approach 2:
The system uses the hydraulic oil's own thermal energy to heat the battery, eliminating the need for external heating sources or additional energy consumption. The heat exchanger enables the hydraulic oil to self-regulate its temperature by transferring excess heat to the battery when the battery needs warming, creating a self-service thermal management mechanism.
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 raises the temperature of the battery, enhancing its performance in cold conditions.
Implementation Method 1
a heat exchanger that is connected to the circulation passage in parallel with the radiator and that performs heat exchange between the cooling water and hydraulic oil
Implementation Method 2
a circulation pump that circulates cooling water through a circulation passage that extends through the battery and a radiator
Data Source
Figure 1
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AI summary
A hydraulic system (2) of a construction machine according to one embodiment includes: an electric motor (21) that is supplied with electric power from a battery (13); a hydraulic pump (33) that is driven by the electric motor (21); and a circulation pump (71) that circulates cooling water through a circulation passage (7) that extends through the battery (13) and a radiator (76). The hydraulic system (2) further includes: a heat exchanger (24) that is connected to the circulation passage (7) in parallel with the radiator (76); a first switching valve (52) that switches whether or not to supply hydraulic oil that has been delivered from the hydraulic pump (33) to the heat exchanger (24); and a second switching valve (74) that switches whether to supply the cooling water that has passed through the battery (13) to the radiator (76) or to the heat exchanger (24).