Refrigerant Control Valve Rotor Rotation Limits
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Solution Overview
Problem
In refrigerant circulation systems, the all-closed state of refrigerant circuits can lead to boiling when the refrigerant temperature is high, which is undesirable and can cause engine component damage.
Innovation Solution
A refrigerant circulation system with a control valve equipped with a rotor that controls the opening and closing of refrigerant circuits, where the operation plan includes an all-passing mode and partial cutoff mode, and the rotor's rotation is prohibited when the refrigerant temperature exceeds an upper limit, preventing all circuits from closing and allowing the opening area of the first refrigerant circuit to increase if a mode switch request is issued.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the rotor is rotated based on the operation plan to control opening and closing states of refrigerant circuits, then the installation space for the control valve is saved and the opening and closing states of the respective refrigerant circuits can be controlled, but all of the refrigerant circuits may be closed due to the structure of the rotor
Solution Approach 1:
The control plan is designed to prevent the all-closed state by anticipating the problem. When the refrigerant temperature is high, the control plan prohibits rotation to positions that would close all circuits, thereby preventing the harmful state before it occurs. This is a preliminary anti-action because it proactively avoids the dangerous configuration rather than reacting after the fact.
Solution Approach 2:
The system uses feedback from the refrigerant temperature to dynamically adjust the permissible rotation range of the rotor. When temperature is high, the feedback signal restricts rotation to positions that keep at least one circuit open. When temperature is low, the feedback signal allows full rotation range. This feedback mechanism resolves the contradiction by adapting the control behavior to current system conditions.
2Device complexity
If all refrigerant circuits are closed, then the control valve structure can be simplified, but the refrigerant is not cooled and is likely to be boiled when the refrigerant has a high temperature
Solution Approach 1:
The control plan preemptively prevents the all-closed state when refrigerant temperature is high by restricting the rotor's permissible positions. This preliminary anti-action ensures that at least one cooling circuit remains open, allowing continuous heat dissipation and preventing refrigerant boiling, while still permitting the simplified rotor structure.
Solution Approach 2:
The system dynamically adjusts the operational constraints of the rotor based on refrigerant temperature. The permissible rotation range is not fixed but varies dynamically with temperature conditions. This dynamic adaptation allows the simplified control structure to function safely across different operating conditions without requiring complex additional components.
3Adaptability or versatility
If the opening degrees of the respective branch valves are independently controlled, then the flow rates of the refrigerant can be individually controlled, but the device complexity increases
Solution Approach 1:
The patent merges the control functions of multiple branch valves into a single rotary valve mechanism. By combining all the opening and closing operations into one rotational motion, the system achieves individual circuit control capability while avoiding the complexity of multiple independently actuated valves. This merging principle resolves the contradiction between adaptability and device complexity.
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
Prevents refrigerant boiling by prohibiting rotor rotation during high-temperature conditions and increasing the opening area of the first refrigerant circuit to facilitate heat exchange, thus reducing the refrigerant temperature and avoiding engine damage.
Implementation Method 1
a first refrigerant circuit for returning a refrigerant that passes through a main body of an internal combustion engine to the main body after causing the refrigerant to perform heat exchange with a first heat exchanger
Implementation Method 2
a control valve that is provided in the first refrigerant circuit, and includes a rotor that rotates around a rotation axis
Implementation Method 3
the controller is programmed to prohibit rotation of the rotor following a mode switch request, when a temperature of the refrigerant which passes through the main body is higher than an upper limit temperature of the refrigerant
Implementation Method 4
increasing the opening area of the first refrigerant circuit to facilitate heat exchange, thus reducing the refrigerant temperature
Data Source
AI summary
In order to shift a rotation angle of a rotor to a region of a normal mode (for example, a region c) from a region of a heater cut mode (for example, a region e), the rotation angle needs to pass through a region where a flow rate of a refrigerant which is caused to flow through all branch channels becomes zero (a region d). When the refrigerant has a high temperature, there is a possibility of the refrigerant being not cooled, and boiling. Therefore, when a request to switch a normal mode and a heater cut mode is issued, permission/non-permission of switch of the mode is determined by comparison of a temperature of the refrigerant detected by the temperature sensor 26 and an upper limit temperature of the refrigerant.