Refrigerant charging using weight and flow rate measurements
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Solution Overview
Problem
Current refrigerant charging processes in vehicle AC systems are inefficient due to the need for multiple stages, including slow charge and compensation stages, which prolong the charging time and introduce inaccuracies due to varying hose lengths and back pressure, making it desirable to maximize the fast-charge stage and minimize the slow charge stage.
Innovation Solution
A system that utilizes weight measurements and calculations to determine the flow rate of refrigerant, allowing for a maximally utilized fast-charge stage with an additional compensation mode to optimize accuracy, eliminating the need for specialized instruments and minimizing the slow charge stage by using solenoids and a controller to manage the flow rate and pressure differential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the charge process uses multiple stages (fast charge, slow charge, compensation), then the charging accuracy is improved, but the total charging time increases
Solution Approach 1:
The patent changes the control parameter from pressure differential (traditional method) to flow rate measurement. By directly measuring and controlling the refrigerant flow rate throughout the entire charging process, the system maintains accuracy without requiring multiple stages, thus reducing total charging time while preserving charging accuracy within ±15 grains
Solution Approach 2:
The patent replaces the mechanical multi-stage charging system with an electronic control system that uses flow rate sensors and electronic solenoid valves. This substitution allows for precise, continuous control of refrigerant flow, eliminating the need for manual stage transitions and reducing overall charging time while maintaining accuracy
2Measurement precision
If the slow charge stage is used to improve accuracy, then the charging precision is improved, but the charging speed decreases
Solution Approach 1:
The patent implements continuous flow rate measurement and control throughout the entire charging process, eliminating the interruption between fast charge and slow charge stages. The flow rate is continuously monitored and adjusted, maintaining both speed and precision without the need to switch between different charging modes
Solution Approach 2:
The system uses real-time flow rate measurement as feedback to continuously adjust the solenoid valve opening, maintaining optimal charging speed while ensuring accuracy. The controller constantly monitors the actual flow rate and modifies the valve position to keep the charging process within the desired accuracy range of ±15 grains
3Measurement precision
If hose compensation is applied to account for refrigerant remaining in hoses, then the charging accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the hose compensation calculation from the physical charging process and integrates it into the electronic control system. By measuring the actual flow rate and using electronic control to account for hose volume, the system eliminates the need for separate compensation mechanisms while maintaining charging accuracy
Solution Approach 2:
The system uses electronic measurement and calculation to create a virtual model of the hose compensation rather than requiring physical adjustment mechanisms. The controller calculates the equivalent hose compensation based on flow rate measurements and system parameters, replacing complex mechanical compensation devices with simple computational logic
4Productivity
If the fast charge stage is maximized to reduce charging time, then the productivity is improved, but the charging accuracy deteriorates
Solution Approach 1:
The patent replaces traditional mechanical flow control mechanisms with electronic solenoid valves and digital flow rate measurement. This substitution enables precise electronic control of the refrigerant flow throughout the fast charge process, maintaining accuracy within ±15 grains while operating at high speed without requiring slow charge stages
Solution Approach 2:
The system changes from pressure-based control to flow rate-based control, allowing the entire charging process to operate in a fast charge mode. By directly measuring and controlling flow rate rather than relying on pressure differential, the system maintains accuracy while maximizing charging speed and eliminating the need for multiple stages
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 enables accurate and efficient refrigerant charging, reducing the overall charging time and improving accuracy by relying solely on weight measurements and calculations to manage the flow rate, ensuring precise refrigerant delivery without specialized instruments.
Implementation Method 1
opening a set of charge solenoid valves between the two transfers refrigerant to the air conditioning system because of the pressure difference
Implementation Method 2
tank weight scales on the ACS machines may not have the sensitivity to accurately keep up with the transfer amount
Data Source
AI summary
An air condition service machine for charging an air conditioner with refrigerant in a fast-charge mode, the fast-charge mode controlled based upon the changing weight rate of a refrigerant tank providing the supply of refrigerant to the air conditioner. The embodiment may also include a compensation mode to provide greater accuracy of the charge after completion of the fast-charge mode. The rate of refrigerant flow is monitored and an end time as opposed to weight target ends the charge.