Dual-Compressors Vehicle HVAC Control for Engine-Off Cooling
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Solution Overview
Problem
Existing vehicle HVAC systems struggle to maintain a comfortable environment for drivers and passengers, especially when the engine is off, due to inefficiencies and the lack of effective cooling solutions at rest stops.
Innovation Solution
A climate system that includes a primary air conditioning system with dual compressors, an engine-driven compressor, and an electrically-driven compressor, controlled by a controller that automatically manages the compressors and engine based on thermal load thresholds to maintain a comfortable temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single engine-driven compressor is used in conventional HVAC systems, then the system structure is simple, but the system cannot provide effective cooling when the engine is off
Solution Approach 1:
The patent combines an engine-driven compressor and an electrically-driven compressor into a single HVAC system with a common refrigerant circuit. The controller coordinates both compressors to work together or independently based on system conditions, enabling cooling functionality both when the engine is running and when it is off, thus resolving the contradiction between cooling availability and system complexity.
Solution Approach 2:
The HVAC system is designed with dual compressors that can operate in multiple modes: the engine-driven compressor operates when the engine is running, and the electrically-driven compressor operates when the engine is off or provides supplemental cooling. This multi-functionality ensures continuous cooling availability while adapting to different operational conditions.
2Temperature
If the engine is continuously running to maintain cooling, then cooling effectiveness is maintained, but fuel consumption increases
Solution Approach 1:
The system dynamically switches between different compressor configurations based on real-time conditions. The controller monitors temperature, thermal load, and engine status to determine whether to use the engine-driven compressor alone, the electrically-driven compressor alone, or both together. This dynamic adaptation allows the system to maintain cooling effectiveness while minimizing fuel consumption by using the electrically-driven compressor when the engine is off.
Solution Approach 2:
The controller adjusts operational parameters including compressor selection, refrigerant flow distribution, and fan speeds based on thermal load calculations. By changing these parameters dynamically, the system optimizes energy efficiency while maintaining the required temperature in the compartment.
3Productivity
If both compressors operate simultaneously, then cooling capacity increases, but system complexity and control difficulty increase
Solution Approach 1:
The controller implements feedback control by continuously monitoring the compartment temperature, comparing it with the desired temperature, and calculating the thermal load. Based on this feedback, the controller automatically determines the appropriate compressor configuration and adjusts refrigerant flow distribution to achieve the desired cooling capacity while simplifying the control logic through rule-based decision making.
Solution Approach 2:
The refrigerant circuit is segmented into multiple zones with independent flow control for each compressor. The controller can selectively activate and control each compressor and its associated refrigerant circuit components, allowing flexible operation modes (engine-driven only, electrically-driven only, or both together) without requiring complex integrated control of the entire system at once.
4Use of energy by moving object
If the electrically-driven compressor is used when thermal load is low, then energy efficiency improves, but the system may not provide sufficient cooling when thermal load is high
Solution Approach 1:
The electrically-driven compressor is designed to provide sufficient cooling capacity for partial or moderate thermal loads, allowing it to operate independently when the thermal load is low to medium. The controller calculates the thermal load and compares it with the cooling capacity of the electrically-driven compressor to determine whether it can handle the load alone or if supplemental cooling from the engine-driven compressor is needed.
Solution Approach 2:
The system uses a composite compressor architecture combining two different compressor types with complementary characteristics. The engine-driven compressor provides high power for large thermal loads, while the electrically-driven compressor provides efficient operation for smaller loads. Together, they form a composite system that covers the full range of thermal load conditions.
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
The system efficiently maintains a comfortable temperature within the vehicle by automatically activating and deactivating the compressors and engine based on thermal load thresholds, ensuring effective cooling even when the engine is off.
Implementation Method 1
activates the first compressor, if the first compressor is off, to compress the refrigerant for cooling the compartment
Implementation Method 2
activates the second compressor, if the second compressor is off, to compress the refrigerant for cooling the compartment
Data Source
AI summary
Disclosed are climate systems for vehicles and methods for controlling the climate systems. In some implementations, a climate system includes: (1) a temperature sensor configured to measure a temperature within the compartment of the vehicle; (2) a first compressor powered by an engine of the vehicle to compress a refrigerant; (3) a second compressor driven by an electric motor to compress the refrigerant; and (4) a controller electrically coupled to the first compressor and the second compressor. The controller configured to: (1) calculate a thermal load of the compartment based on a difference between a desired temperature and a measured temperature; and, (2) based on the calculated load, selectively activate: (i) the engine, (ii) the first compressor, and/or (iii) the second compressor.