HVAC Control Door with Bleed Path for Defrost Vent Pressure Balance
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Solution Overview
Problem
The existing climate control systems for vehicles face challenges in efficiently and cost-effectively controlling the distribution of air to windshield defrost vents and side window defrost vents, particularly in managing pressure and noise, vibration, and harshness (NVH) due to differing pressure requirements and air distribution changes across operating modes.
Innovation Solution
The implementation of a rotatable control door in the conduit system that selectively adjusts between positions to block or allow airflow through a bleed path, combined with a control feature to manage volumetric flow rate and pressure, minimizes NVH and ensures consistent pressure at the outlets of side window defrost vents across various operating modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single door is used to control airflow to both windshield defrost vents and side window defrost vents, then device complexity is reduced, but the ability to independently control pressure and flow rate to each vent type deteriorates
Solution Approach 1:
The single door is segmented into two functional portions: a first portion that controls airflow to windshield defrost vents and a second portion that controls airflow to side window defrost vents. This segmentation allows each portion to be independently adjusted to meet different pressure and flow rate requirements for each vent type, resolving the contradiction between reduced device complexity and independent control capability
Solution Approach 2:
The single door is designed to perform multiple functions by incorporating both the first portion for windshield defrost control and the second portion for side window defrost control. This multi-functionality allows one component to replace what would traditionally require separate doors for each vent type, reducing overall device complexity while maintaining independent control over different airflow paths
2Object-affected harmful factors
If airflow to side window defrost vents is restricted to reduce NVH, then noise, vibration, and harshness are reduced, but the volumetric flow rate to these vents decreases
Solution Approach 1:
The door incorporates different local qualities in its two portions: the first portion has characteristics optimized for controlling airflow to windshield defrost vents, while the second portion has characteristics optimized for controlling airflow to side window defrost vents. This allows the second portion to be configured with specific flow resistance properties that reduce NVH while maintaining adequate volumetric flow rate for side window defrost functionality
3Productivity
If the door is positioned to optimize airflow distribution, then air distribution efficiency is improved, but the pressure drop across the conduit increases
Solution Approach 1:
The door is designed to be dynamically adjustable, allowing it to rotate to different angular positions. This dynamic positioning capability enables optimization of airflow distribution efficiency for different operating conditions while managing pressure drop characteristics. The door can be adjusted to balance the trade-off between distribution efficiency and pressure loss based on specific vehicle operating modes
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 solution effectively controls air distribution to both windshield and side window defrost vents, reducing NVH and maintaining consistent pressure, while minimizing the need for additional components, thus enhancing the efficiency and cost-effectiveness of the air handling system.
Implementation Method 1
The control door selectively rotates between a first position and a second position. The first position blocks passage of the air flowing through the conduit. The second position blocks passage of the air flowing through a first portion of the conduit and allows the air to flow through a second portion of the conduit.
Implementation Method 2
A control feature is disposed in the second portion of the conduit to control at least one of a volumetric flow rate and a pressure of the air flowing through the second portion.
Data Source
AI summary
An air handling system for a heating, ventilation, and air conditioning system of a motor vehicle includes a conduit configured to convey air from the air handling system to a vent of the air handling system. A control door is rotatably disposed in the conduit. The control door selectively rotates between a first position and a second position. The first position blocks passage of the air flowing through the conduit. The second position blocks passage of the air flowing through a first portion of the conduit and allows the air to flow through a second portion of the conduit. A control feature is disposed in the second portion of the conduit to control at least one of a volumetric flow rate and a pressure of the air flowing through the second portion.