Vehicle Air Conditioning Compressor Speed Control for Noise Masking
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Solution Overview
Problem
Vehicle air conditioning devices experience noise issues due to the operation of electric compressors, particularly at low vehicle speeds, which can be perceived as discomfort by occupants and require additional measures like sound insulation or mass increases in compressors.
Innovation Solution
A vehicle air conditioning device with a controller that adjusts the compressor's rotation speed based on vehicle speed and fan device rotation speed, setting upper limit values to minimize noise perception by masking compressor noise with fan noise, without increasing compressor mass or insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the compressor mass is increased to reduce noise, then noise perception is reduced, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent introduces a fan device as an intermediary noise source to mask the compressor noise. The fan generates airflow noise that covers up the compressor operation sound, particularly effective at low vehicle speeds when compressor noise is most noticeable to occupants.
Solution Approach 2:
The controller dynamically adjusts the fan rotation speed based on vehicle speed conditions. At low vehicle speeds, the fan operates at higher rotation speeds to generate sufficient masking noise. This parameter adjustment allows noise control without permanently increasing compressor mass or insulation.
2Object-affected harmful factors
If sound insulation measures are added to reduce noise perception, then noise perception is reduced, but the device complexity and manufacturing cost increase
Solution Approach 1:
Instead of adding physical sound insulation barriers, the system uses acoustic masking through the fan device. The fan's airflow noise serves as an intermediary that psychologically masks the compressor noise, achieving noise reduction without additional insulation structures.
Solution Approach 2:
The patent replaces mechanical sound insulation measures with an acoustic field-based solution. Rather than physically blocking sound transmission through insulation materials, the system uses generated sound fields from the fan to mask the unwanted compressor noise.
3Productivity
If the compressor rotation speed is increased to improve cooling performance, then cooling performance is improved, but noise perception increases at low vehicle speeds
Solution Approach 1:
The fan device acts as a noise mask that allows the compressor to operate at higher rotation speeds for improved cooling performance. The fan-generated noise covers up the compressor noise, enabling productivity improvement without the usual noise penalty at low vehicle speeds.
Solution Approach 2:
The system dynamically adjusts fan rotation speed in response to compressor operation and vehicle speed conditions. When the compressor operates at high speeds, the fan increases its rotation to provide adequate noise masking, allowing flexible optimization of both cooling performance and noise perception.
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
Improves cooling performance while reducing noise perception and avoiding the need for mass increases or sound insulation, maintaining sufficient refrigeration cycle performance with a low-mass electric compressor.
Implementation Method 1
The condenser cools the refrigerant discharged from the compressor by exchanging heat between the refrigerant and air
Implementation Method 2
The evaporator cools air-conditioning air, which is to be blown into a passenger compartment, by exchanging heat between the refrigerant discharged from the expansion valve and the air-conditioning air
Data Source
AI summary
A vehicle air conditioning device includes a compressor and a controller. The controller is configured to set an upper limit value of the rotation speed of the compressor based on a combination of whether the speed of the vehicle is lower than a predetermined speed and whether a rotation speed of a fan device for a condenser is lower than a predetermined rotation speed.