Active Air Flap Control Using Preceding Vehicle Wake Prediction
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Solution Overview
Problem
Conventional active air flap (AAF) control systems do not adequately consider the wake generated by preceding vehicles, leading to insufficient cooling air volume and increased energy consumption for cooling the power train and power electronics.
Innovation Solution
An apparatus and method that includes sensors and a processing device to detect vehicle status information, calculate the initial speed of the wake generated by a preceding vehicle, and adjust the AAF opening degree to compensate for the reduced airflow, using vehicle speed, inter-vehicle distance, and air resistance coefficients to determine the corrected target opening degree.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the AAF opening degree is controlled based on conventional parameters (vehicle speed, engine load, cooling temperature) without considering wake effects, then the control system remains simple, but the cooling air volume becomes insufficient when a preceding vehicle is present
Solution Approach 1:
The system performs preliminary calculation of wake speed based on inter-vehicle distance and preceding vehicle characteristics before the wake actually reaches the vehicle. This allows the AAF opening degree to be pre-adjusted to compensate for the upcoming wake effect, ensuring adequate cooling air volume without waiting for the wake to arrive
Solution Approach 2:
The processing device acts as an intermediary that receives information from multiple sensors (distance sensor for inter-vehicle distance, communication device for preceding vehicle speed), calculates wake speed using a predetermined model, and translates this into corrected AAF opening degree commands. This intermediary processing layer integrates wake compensation without requiring direct modification of the AAF control mechanism
2Reliability
If the AAF opening degree is increased to compensate for wake effects, then the cooling air volume is maintained, but the energy consumption increases due to larger flap actuation and potential excessive cooling
Solution Approach 1:
The system applies partial compensation by calculating the wake speed and determining the precise degree of opening adjustment needed based on the predicted air flow reduction. Rather than simply increasing the opening degree maximally, it applies just enough additional opening to compensate for the expected wake effect, avoiding excessive cooling and associated energy waste
Solution Approach 2:
The system dynamically changes the AAF opening degree parameter based on calculated wake speed. By continuously adjusting this parameter in response to varying inter-vehicle distances and preceding vehicle conditions, the system optimizes the balance between maintaining adequate cooling air volume and minimizing energy consumption from unnecessary cooling
3Measurement precision
If the wake speed is calculated using detailed vehicle information (air resistance coefficient, overall height), then the wake speed prediction becomes more accurate, but the data acquisition and processing complexity increases
Solution Approach 1:
The system uses a communication device that can serve multiple functions: it communicates with the preceding vehicle for various vehicle-to-vehicle information exchange purposes, and simultaneously extracts the specific data needed for wake speed calculation (vehicle speed, air resistance coefficient, overall height). This multi-functional use of the communication device avoids adding dedicated sensors or measurement systems solely for wake prediction
Solution Approach 2:
Instead of directly measuring the wake speed (which would require complex flow sensors and measurement systems), the system creates a computational model that copies the essential physics of wake generation. It uses the preceding vehicle's parameters in a predetermined calculation model to predict wake speed, avoiding the need for direct physical measurement of the wake itself
Data Source
AI summary
An apparatus for controlling an active air flap (AAF) of a vehicle may include a plurality of sensors configured to detect status information of the vehicle; an opening degree controller configured to control an opening degree of the AAF; and a processor configured to determine a target flow and a target opening degree of the AAF based on the status information, calculate an initial speed of a wake generated by a preceding vehicle based on vehicle information of the preceding vehicle, obtain a speed of the wake when the wake arrives the vehicle based on a speed of the vehicle, an inter-vehicle distance between the vehicle and the preceding vehicle, and the initial speed of the wake, correct the target opening degree based on the speed of the wake, and adjust the opening degree of the AAF corresponding to the corrected target opening degree.