Vehicle HVAC Air Inlet Flap Layout for Ram Pressure Compensation
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Solution Overview
Problem
Existing air conditioning units in motor vehicles face issues with undesired bypass flows and ram pressure regulation, leading to inefficiencies, noise, and increased complexity, particularly at high speeds and low air intake requirements.
Innovation Solution
The air conditioning unit incorporates a bypass flow duct with a ram pressure air guiding device and an air guiding device, allowing independent control of flow cross sections, minimizing bypass flows and optimizing ram pressure compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flow cross section of the fresh air inlet is greatly reduced to compensate for high ram pressure, then bypass flows are avoided, but the air intake efficiency decreases and noise increases
Solution Approach 1:
The air inlet system is segmented into two independent control paths: the main fresh air inlet and the bypass flow duct. Each path has its own air guiding device, allowing independent control of flow cross sections. This segmentation enables the main inlet to maintain larger opening for efficiency while the bypass duct provides precise ram pressure compensation, resolving the contradiction between preventing bypass flows and maintaining air intake efficiency.
Solution Approach 2:
The bypass flow duct acts as an intermediary mechanism for ram pressure compensation. Instead of directly throttling the main fresh air inlet (which causes noise and efficiency loss), the system uses the bypass duct as a mediator to compensate for ram pressure effects. The bypass duct's air guiding device can be independently adjusted to provide the necessary compensation without affecting the main airflow path, thus preventing bypass flows while maintaining efficiency.
2Device complexity
If a single flap is used to control the fresh air inlet, then device complexity is reduced, but precise ram pressure regulation becomes difficult
Solution Approach 1:
The control function is segmented between two independent air guiding devices: one for the main fresh air inlet and another for the bypass flow duct. This segmentation allows each device to specialize in specific control tasks, with the bypass duct's device handling precise ram pressure compensation. The independent control paths enable precise regulation without requiring overly complex single-flap mechanisms.
Solution Approach 2:
The system adds another dimension of control by introducing the bypass flow duct as a separate control path. Instead of relying on a single flap to simultaneously manage both air intake and ram pressure compensation, the system distributes control across two dimensions: the main inlet for primary airflow management and the bypass duct for specialized ram pressure compensation. This dimensional addition enables precise regulation while keeping individual components relatively simple.
3Use of energy by moving object
If the air conditioning unit operates with less fresh air and more circulating air, then energy consumption decreases, but ram pressure effects become more significant
Solution Approach 1:
The bypass flow duct serves as an intermediary mechanism that specifically addresses ram pressure effects. When the system operates with less fresh air (to save energy), the bypass duct's air guiding device can be independently adjusted to provide precise ram pressure compensation. This intermediary control path allows the system to maintain low energy consumption while effectively managing the heightened ram pressure effects that occur at low fresh air intake conditions.
Solution Approach 2:
The system employs dynamic, independent control of the bypass flow duct's air guiding device that can be continuously adjusted based on operating conditions. When energy-saving mode is activated with reduced fresh air intake, the bypass device dynamically compensates for increased ram pressure effects. This dynamic adjustment capability allows the system to optimize the balance between energy consumption and ram pressure management across varying operating points.
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
Ensures robust, precise, and quiet operation with minimal installation space and cost, reducing energy consumption and maintaining passenger compartment comfort.
Implementation Method 1
an air guiding device in each case for independently varying flow cross sections of the air inlets. In each case the air guiding device is designed as an air flap which is movably mounted between two end positions
Implementation Method 2
The cause of the bypass flows is running the motor vehicle at high speed. In this case, at the inlet for the fresh air, there is a high ram pressure of the air
Data Source
AI summary
Air conditioning unit for a motor vehicle and climate control system with the air conditioning unit having a casing with at least one first air inlet for the intake of fresh ambient air and one second air inlet for the intake of circulating air from a passenger compartment, as well as an air guiding device in each case for independently varying flow cross sections of the air inlets, the air guiding device in each case is designed as an air flap which is arranged movably mounted between two end positions, a bypass flow duct with a ram pressure air guiding device is formed for the first air inlet, and the ram pressure air guiding device is arranged as an air flap movably mounted between two end positions and is designed in such a way as to fully close the bypass flow duct in an end position.