Cooling Fan Noise Control in Electric Heavy Vehicles
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Solution Overview
Problem
Electric heavy vehicles face increased audible noise from cooling fans due to higher ambient temperatures, which is particularly disturbing without the masking effect of an internal combustion engine, especially when batteries are fully charged and regenerative braking generates excess heat.
Innovation Solution
A method and control system that determines a noise threshold for cooling fans, uses look-ahead road data to plan a speed profile that keeps cooling requirements within the fan's capacity, and adjusts fan speed to maintain noise below the threshold, optionally incorporating quiet mode settings and noise measurement feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling fan speed is increased to meet cooling demands, then cooling capacity is improved, but noise level increases
Solution Approach 1:
The system performs preliminary action by using look-ahead road data to predict upcoming cooling demands and proactively adjusting the speed profile before the vehicle reaches sections requiring high cooling. This allows the cooling fan to operate at lower speeds during normal conditions while still meeting peak cooling demands through pre-positioning the vehicle in a speed profile that anticipates future thermal loads.
Solution Approach 2:
The system applies dynamics by implementing a dynamic speed profile that continuously adapts based on real-time conditions including ambient temperature, battery state of charge, regenerative braking opportunities, and predicted road conditions. The cooling fan speed and vehicle speed are dynamically adjusted to balance cooling requirements against noise thresholds, rather than operating at fixed speeds.
2Object-generated harmful factors
If vehicle speed is reduced to lower cooling demands, then noise level decreases, but productivity decreases
Solution Approach 1:
The system uses look-ahead road data to identify upcoming sections with high cooling demands (such as steep climbs or hot ambient conditions) and proactively adjusts the speed profile in advance. This allows the vehicle to maintain higher speeds in sections where cooling demands are lower, while only reducing speed when necessary to meet noise thresholds during high-demand sections, thereby minimizing overall impact on productivity.
Solution Approach 2:
The system changes operational parameters by dynamically adjusting both vehicle speed and cooling fan speed based on real-time conditions. Rather than maintaining a fixed speed profile, the system modifies speed parameters adaptively, reducing vehicle speed only when cooling demands would otherwise cause the cooling fan to exceed noise thresholds, and maintaining higher speeds when cooling demands are manageable.
3Power
If cooling fan operates at high power to meet cooling requirements, then cooling capacity is improved, but noise threshold is exceeded
Solution Approach 1:
The system implements feedback by continuously monitoring actual cooling fan noise levels and comparing them against predetermined noise thresholds. Based on this feedback, the control system dynamically adjusts the cooling fan speed and vehicle speed profile to ensure noise remains below thresholds while still meeting cooling requirements. The feedback loop allows real-time optimization of the balance between cooling capacity and noise emission.
Solution Approach 2:
The system applies parameter changes by dynamically modifying cooling fan speed and vehicle operating parameters based on real-time thermal conditions, ambient temperature, battery state of charge, and noise measurements. Rather than operating at maximum power continuously, the system adjusts power parameters adaptively, increasing cooling fan power only when thermal conditions require it and keeping noise below thresholds through coordinated speed profile adjustments.
4Use of energy by moving object
If regenerative braking is used to charge batteries, then energy efficiency is improved, but cooling demands increase when batteries are full
Solution Approach 1:
The system applies dynamics by continuously monitoring battery state of charge and dynamically adjusting the regenerative braking strategy accordingly. When batteries approach full charge, the system reduces reliance on regenerative braking and transitions to friction braking, thereby reducing the thermal load on the braking system and subsequent cooling demands. This dynamic adjustment allows the system to maintain energy efficiency when batteries can accept charge while avoiding excessive cooling demands when they cannot.
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 reduces cooling fan noise to comfortable levels, enhancing ride comfort and compliance with noise regulations by proactively managing cooling fan speed based on anticipated road conditions and noise thresholds.
Implementation Method 1
Such cooling of the electric propulsion system of the vehicle is often handled by providing one or more cooling fans configured to transport excess heat into the ambient environment of the vehicle
Implementation Method 2
the remaining energy is converted into exhaust heat in for example a dedicated braking resistor
Data Source
Figure 1~2A
Figure 2B~3B
Figure 4
AI summary
A method of noise management in an electric heavy vehicle (100) is provided, including determining a noise threshold and corresponding reduced target speed for a cooling fan (120) providing cooling of a propulsion/braking system (130) of the vehicle, obtaining look-ahead data (140) pertinent to an upcoming section of a road (142), and to determine a speed profile (150) for the vehicle such that a cooling requirement of the propulsion/braking system does not exceed a cooling capacity of the cooling fan running at the reduced target speed. The method further includes, while driving along the section of the road, controlling (122) the cooling fan not to exceed the target speed, and controlling (152) the speed of the vehicle in accordance with the speed profile. A corresponding control system (101), heavy vehicle, computer program and computer program product are also provided.