Vehicle Heat Pump Control for Stable Cabin Discharge Temperature
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Solution Overview
Problem
Conventional heat pump systems for vehicles face issues with temperature convergence instability and increased operational noise due to simultaneous variable control of the compressor and electric heater, leading to passenger dissatisfaction and reduced system durability.
Innovation Solution
A heat pump system that variably controls the compressor based on its revolutions below the maximum limit and operates the electric heater only when the compressor reaches its upper limit, ensuring stable temperature convergence and reducing noise by differentiating the compressor's maximum revolutions according to conditions in the maximum heating mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the compressor and electric heater are simultaneously controlled to satisfy target discharge temperature, then the heating performance is improved, but the temperature convergence stability deteriorates and operational noise increases
Solution Approach 1:
The control method segments the heating control into two distinct stages: first controlling only the compressor to reach a preliminary temperature, then controlling only the electric heater for final temperature adjustment. This segmentation prevents simultaneous control instability and improves temperature convergence stability while maintaining heating performance.
2Temperature
If the compressor operates at maximum revolutions to satisfy heating demand, then the heating performance is improved, but the operational noise increases and passenger satisfaction decreases
Solution Approach 1:
The system dynamically adjusts the compressor's maximum revolutions based on operating conditions such as vehicle speed and outdoor temperature. By making the compressor speed limit variable rather than fixed, the system reduces operational noise during moderate heating conditions while maintaining sufficient heating performance when needed.
Solution Approach 2:
The electric heater serves as an intermediary device that handles final temperature adjustments after the compressor reaches preliminary heating. This allows the compressor to operate at lower, quieter revolutions while the electric heater provides the additional heating capacity needed to meet the target temperature.
3Power
If the compressor revolutions are continuously increased to meet heating demand, then the heating capacity is improved, but the system durability decreases
Solution Approach 1:
The control method uses partial action by operating the compressor at variable revolutions that are often below maximum capacity. The electric heater supplements the heating capacity when needed, allowing the compressor to avoid continuous maximum operation and thereby improving system durability while maintaining sufficient heating capacity.
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 prevents temperature instability, reduces passenger dissatisfaction from compressor noise, and enhances system durability by controlling the compressor's revolutions and electric heater operation effectively.
Implementation Method 1
a compressor (100) connected to a refrigerant circulation line to compress and discharge refrigerant
Implementation Method 2
an interior heat exchanger (110) connected to the refrigerant circulation line and arranged inside an air-conditioning case
Implementation Method 3
an electric heater (115) mounted inside the air-conditioning case (150)
Data Source
AI summary
Disclosed therein are a heat pump system for a vehicle and a method of controlling the heat pump system, which variably controls only a compressor if the number of revolutions of the compressor is less than the upper limit of the number of the maximum revolutions of the compressor and operates an electric heater only when the number of revolutions of the compressor reaches the upper limit of the number of the maximum revolutions of the compressor in order to satisfy a target discharge temperature in a heat pump mode, thereby preventing that convergence of an air discharge temperature of the interior of the vehicle is deteriorated or becomes unstable when the compressor and the electric heater are variably controlled at the same time in order to satisfy the target discharge temperature.