Engine Cooling Flow Resistance Adjustment
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Solution Overview
Problem
The engine cooling system experiences thermal gradients and component degradation due to uneven coolant distribution across heat exchangers, particularly in the sub-cooled return line, as engine speed decreases, leading to reduced coolant flow and pressure, which can result in non-homogeneous temperatures and potential engine shutdown.
Innovation Solution
Adjusting the resistance of the radiator main return line to be greater than the sub-cooled return line when engine speed is below a threshold, using a restrictive element like a dual-orifice ball valve, to ensure complete flooding of all components by increasing coolant flow through the sub-cooled return line, thereby maintaining homogeneous temperatures across the cooling system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the sub-cooled return line includes more heat exchangers to increase cooling capacity, then the cooling performance is improved, but the flow resistance increases causing incomplete flooding at low engine speeds
Solution Approach 1:
The patent applies a dynamically adjustable restrictive element (ball valve with movable ball) in the radiator main return line that changes flow resistance based on engine speed. At low engine speeds, the ball moves to block the larger first orifice and open the smaller second orifice, increasing resistance in the radiator main return line to redirect flow to the sub-cooled return line and ensure complete flooding of its heat exchangers.
Solution Approach 2:
The patent changes the flow resistance parameter in the radiator main return line by switching between two orifice sizes. The restrictive element transitions between two discrete resistance states, effectively changing the flow distribution parameter to maintain complete flooding in the sub-cooled return line at low engine speeds while allowing higher flow through the radiator main return line at high engine speeds.
2Device complexity
If the coolant pump is driven by engine crankshaft to reduce complexity, then the device complexity is reduced, but the coolant flow and pressure decrease at low engine speeds causing thermal gradients
Solution Approach 1:
The patent changes the flow resistance parameter in the radiator main return line using an engine-speed-sensitive restrictive element. As engine speed decreases, the restrictive element automatically increases resistance in the radiator main return line, redirecting coolant flow to ensure complete flooding of the sub-cooled return line heat exchangers and maintaining homogeneous temperatures without requiring a more complex pump system.
Solution Approach 2:
The restrictive element acts as an intermediary device that mediates between the engine speed (drive system characteristics) and the coolant flow distribution. It translates engine speed variations into appropriate flow resistance adjustments, ensuring complete flooding in the sub-cooled return line while maintaining the simple engine-driven pump configuration.
3Productivity
If the radiator main return line has lower resistance to maximize coolant flow, then the coolant flow rate is improved, but the sub-cooled return line components are not completely flooded at low engine speeds
Solution Approach 1:
The patent employs a dynamic flow distribution mechanism where the restrictive element's position changes with engine speed. At high engine speeds, the ball valve allows maximum flow through the radiator main return line by opening the larger first orifice. At low engine speeds, it automatically increases resistance by blocking the first orifice and opening the smaller second orifice, redirecting sufficient flow to completely flood the sub-cooled return line heat exchangers.
Solution Approach 2:
The patent applies different flow resistance characteristics to different return lines based on local requirements. The restrictive element creates localized high resistance in the radiator main return line at low engine speeds, while the sub-cooled return line maintains lower resistance to ensure complete flooding. This local differentiation of flow characteristics ensures optimal cooling in both parallel paths.
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 approach ensures complete flooding of heat exchangers in the sub-cooled return line, reducing thermal gradients and mechanical stress, and preventing unintended engine shutdowns by maintaining optimal coolant distribution at varying engine speeds.
Implementation Method 1
adjusting a first resistance of a radiator main return line to be greater than a second resistance of a sub-cooled return line
Implementation Method 2
a cooling system may route coolant through a single cooling circuit that includes the engine, a coolant pump, a radiator, and additional heat exchangers
Implementation Method 3
The coolant pump may be driven by an engine crankshaft and as engine speed decreases, flow and pressure in the engine cooling system may decrease
Data Source
AI summary
Various methods and systems are provided for adjusting flow resistances in an engine cooling system. In one example, a method for an engine includes adjusting a first resistance of a radiator main return line to be greater than a second resistance of a sub-cooled return line in response to an engine speed below a threshold speed, the sub-cooled return line arranged in parallel with the radiator main return line in an engine cooling system.