Expansion Tank Pneumatic Pressurization for Low-Temperature Cooling
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Solution Overview
Problem
In cooling circuits of motor vehicles with electrified drive trains, low operating temperatures and high viscosity of coolants lead to reduced pressure build-up in expansion tanks, causing acoustic abnormalities, hose collapse, and pump cavitation, resulting in reduced efficiency and hydraulic power.
Innovation Solution
An expansion tank arrangement with a pneumatic connection and valve in the pneumatic supply line allows for selective pressurization of the expansion tank using a pneumatic medium, preventing pressure drops and maintaining adequate operation even at low temperatures and high viscosities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the cooling circuit operates at low temperatures with high viscosity coolant, then heat transfer efficiency is improved, but pressure build-up in the expansion tank is reduced causing cavitation and hose collapse
Solution Approach 1:
The patent introduces a pneumatic pressurization system that uses a compressor to deliver compressed air through a control valve to the expansion tank. This pneumatic approach compensates for the insufficient pressure build-up caused by low temperature and high viscosity conditions, preventing cavitation and hose collapse while maintaining the beneficial low operating temperature
Solution Approach 2:
The patent changes the pressure parameter in the expansion tank by introducing an active pressurization system. The control valve regulates the amount of compressed air delivered to the expansion tank, dynamically adjusting the pressure to compensate for the reduced pressure build-up that occurs at low temperatures with high viscosity coolant
2Temperature
If the coolant viscosity is high at low temperatures, then heat transfer in components is improved, but pump power requirements increase and hydraulic power is reduced
Solution Approach 1:
The pneumatic pressurization system provides additional hydraulic power through compressed air delivery to the expansion tank. This external pneumatic assistance compensates for the power losses due to high viscosity, maintaining adequate flow rates without requiring excessive pump power
Solution Approach 2:
The compressor delivers compressed air in advance to the expansion tank, creating a pressure reservoir that proactively compensates for the high viscosity effects before they cause cavitation or flow restrictions, rather than reacting after problems occur
3Device complexity
If the expansion tank is not adequately pressurized, then system simplicity is maintained, but acoustic abnormalities and cavitation occur reducing system reliability
Solution Approach 1:
The patent adds a pneumatic pressurization system with a compressor and control valve to the expansion tank. This relatively simple pneumatic addition effectively prevents cavitation, hose collapse, and acoustic abnormalities, significantly improving system reliability without requiring major structural changes to the cooling circuit
Solution Approach 2:
The control valve acts as an intermediary device that regulates the flow of compressed air from the compressor to the expansion tank. This simple valving mechanism provides precise control over the pressurization process, maintaining reliable operation while keeping the overall system design straightforward
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 enhances the operational efficiency of the cooling system by maintaining pressure in the expansion tank, reducing undesirable effects such as cavitation and improving hydraulic power, thus ensuring effective heat transfer and dissipation.
Implementation Method 1
a pneumatic connection (12) for connecting the expansion tank (6) to a pneumatic supply device (13) for pressurizing the expansion tank (6) with a pneumatic medium by means of a pneumatic supply line (14)
Implementation Method 2
A valve (15) for influencing the pressurization of the expansion tank (6) is provided in the pneumatic supply line (14) between the expansion tank (6) and the pneumatic supply device (13)
Implementation Method 3
these units are integrated into a cooling circuit, which may also be designed, for example, as a low-temperature cooling circuit
Data Source
AI summary
An expansion tank arrangement is for a cooling circuit. The expansion tank arrangement has: an expansion tank having a housing with an internal volume configured to receive a cooling fluid; a fluid connection configured to connect the expansion tank to the cooling circuit for supplying the cooling fluid; and a pneumatic connection configured to connect the expansion tank to a pneumatic supply device for pressurizing the expansion tank with a pneumatic medium using a pneumatic supply line. A valve that is configured to influence the pressurization of the expansion tank is in the pneumatic supply line between the expansion tank and the pneumatic supply device.