EV Cooling Control for Compressor-Fan Noise Limits
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Solution Overview
Problem
Electrically driven vehicles face noise issues due to high rotational speeds of compressors and fans, which compromise cooling capability when noise suppression is attempted, as existing cooling fan control devices reduce fan rotational speed to limit noise but decrease cooling efficiency.
Innovation Solution
A cooling device for electrically driven vehicles that includes a compressor, fan, temperature and pressure detectors, and a controller that adjusts compressor and fan rotational speeds based on detected conditions to maintain cooling capability while limiting noise within a predetermined noise regulation value, prioritizing lower fan speeds for higher compressor speeds to minimize noise and maintain efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotational speed of the compressor or fan is increased to achieve higher cooling capability, then the cooling performance is improved, but noise increases beyond acceptable levels
Solution Approach 1:
The patent implements dynamic control of fan rotational speed based on real-time monitoring of compressor rotational speed and coolant temperature. The control device adjusts fan speed dynamically rather than operating at fixed high speed, allowing the system to maintain cooling capability while adapting fan speed to actual cooling requirements, thereby reducing noise during low-demand periods
Solution Approach 2:
The patent changes the operational parameters of the fan by setting different rotational speed thresholds and adjustment rates based on compressor speed ranges and temperature conditions. By modifying these parameters dynamically, the system achieves optimal balance between cooling performance and noise reduction across different operating conditions
2Object-generated harmful factors
If the fan rotational speed is reduced to suppress noise, then noise is decreased, but cooling capability deteriorates
Solution Approach 1:
The control device continuously monitors compressor rotational speed and coolant temperature, using this feedback to adjust fan rotational speed in real-time. This closed-loop control ensures the fan operates at the minimum necessary speed to maintain cooling capability, preventing both excessive noise and insufficient cooling
Solution Approach 2:
The system transitions from static fan speed control to dynamic adjustment based on actual cooling demand. The fan speed is continuously adapted to match the cooling requirements determined by compressor speed and temperature conditions, maintaining cooling effectiveness while minimizing noise
3Loss of time
If high rotational speeds are maintained for quick battery charging during vehicle stop, then charging speed is improved, but noise becomes particularly annoying to occupants
Solution Approach 1:
The control device implements periodic monitoring and adjustment of fan speed during battery charging operations. Rather than maintaining constant high speed, the system periodically assesses cooling requirements and adjusts fan speed accordingly, providing necessary cooling during quick charging while reducing continuous noise exposure for vehicle occupants
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 solution effectively suppresses noise during cooling while minimizing the decrease in cooling capability, allowing for efficient operation and reduced power consumption by optimizing compressor and fan rotational speed combinations.
Implementation Method 1
a compressor (3) that compresses the coolant
Implementation Method 2
a condensing device (4) that condenses, by cooling, the coolant compressed by the compressor (3)
Implementation Method 3
a fan (41) that draws outside air into the condensing device (4)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
When at least one of a first condition that a set compressor rotational speed is equal to or less than a compressor rotational speed limit set in advance based on a predetermined noise regulation value and a second condition that a set fan rotational speed is equal to or less than a fan rotational speed limit set in advance based on the predetermined noise regulation value is not satisfied, a cooling device 1 sets a corrected compressor rotational speed such that noise generated with actuation of a compressor 3 and a fan 41 takes the predetermined noise regulation value or less, and sets a corrected fan rotational speed based on the corrected compressor rotational speed. The cooling device 1 sets a lower value of the corrected fan rotational speed for a higher corrected compressor rotational speed.