Expansion Tank With Actuated Bladder For Coolant Level Control
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Solution Overview
Problem
Conventional vehicle cooling system expansion tanks face challenges in maintaining the coolant elevation level above the engine coolant fill level due to engine packaging constraints, leading to potential air entrapment and inefficient gas removal.
Innovation Solution
An expansion tank design featuring a bladder with a flexible membrane actuated by an engine-start or temperature-activated mechanism, which adjusts the coolant elevation level by moving air volumes within the tank to ensure the coolant level remains at or above the engine fill level, utilizing a communicating line to manage air displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the expansion tank is mounted at a lower position due to engine packaging constraints, then the tank can be integrated into the engine bay, but the coolant elevation level falls below the engine coolant fill level
Solution Approach 1:
The patent employs a movable bladder that dynamically adjusts its position within the expansion tank based on coolant temperature and volume. When the engine is cold or stopped, the bladder moves to allow lower coolant levels. When the engine is running and coolant expands, the bladder rises to maintain the coolant surface above the fill level line, thus resolving the contradiction between low tank mounting and adequate coolant elevation.
Solution Approach 2:
The system changes the physical state and position of the bladder based on temperature parameters. The bladder is positioned at different elevations depending on whether the engine is cold or hot, thereby adjusting the coolant level relative to the fill level line without changing the tank's fixed mounting position.
2Reliability
If the coolant elevation level is below the engine fill level line, then air may be trapped in the cooling system, but raising the tank position is constrained by engine packaging
Solution Approach 1:
The movable bladder dynamically adjusts to maintain the coolant-air interface above the fill level line regardless of the tank's fixed low mounting position. This ensures that air can be effectively vented through the vent line while the tank remains in a packaging-friendly location.
Solution Approach 2:
The bladder acts as an intermediary element between the coolant and the tank wall, allowing the system to decouple the tank's fixed mounting position from the functional requirement of maintaining adequate coolant elevation for air removal.
3Reliability
If a movable bladder is added to adjust coolant level, then coolant elevation can be maintained above fill level, but device complexity increases
Solution Approach 1:
The bladder is designed to move automatically based on coolant temperature and volume changes without requiring external actuators or complex control systems. The bladder's movement is driven by the natural expansion and contraction of the coolant and the compression of trapped air, making the system self-regulating and minimizing added complexity.
Solution Approach 2:
The system utilizes the phase transition and thermal expansion properties of the coolant and trapped air to drive the bladder's movement. As coolant heats up and expands, it compresses the air pocket and pushes the bladder upward, automatically maintaining the required coolant level without mechanical actuators.
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 design effectively maintains the coolant elevation level above the engine fill level, ensuring efficient air removal and system pressure management, even when the tank is positioned lower than conventional systems, thereby enhancing the overall performance of the vehicle cooling system.
Implementation Method 1
when the engine is stopped or is below a predetermined temperature, the flexible membrane is moveable to a first position which lowers the coolant elevation level, and when the engine is started or reaches a predetermined temperature, the flexible membrane is moveable to a second position which raises the coolant elevation level
Data Source
AI summary
An expansion tank (10) for a vehicle cooling system (18) of an engine using a liquid coolant (16) includes a tank body (12) defining a first volume (V1) containing coolant (16), wherein the coolant defines a variable coolant elevation level (CEL) within the tank body. The tank body (12) also defines an upper volume (20) containing air. A bladder (14) is disposed in the tank body (12) and defines a second volume (V2) containing air. The bladder (14) includes a flexible membrane (36) actuated by an actuator (46). When the engine is stopped or is below a predetermined temperature, the flexible membrane (36) is moveable to a first position (FP) which lowers the coolant elevation level (CEL), and when the engine is started or reaches a predetermined temperature, the flexible membrane (36) is moveable to a second position (SP) which raises the coolant elevation level. A communicating line (38) is in fluid communication between the upper volume (20) and the second volume (V2) to fluidly communicate air therebetween.