Vehicle HVAC Air Inlet Valve Layout for Quiet Recirculation
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Solution Overview
Problem
Conventional HVAC systems in vehicles experience a significant increase in noise levels when operating with recirculated air from the passenger compartment, which is undesirable and has not been adequately addressed.
Innovation Solution
The HVAC system incorporates a movable valve system with blocking surfaces that can selectively control the flow of air through multiple inlets, allowing for the integration of both outside and recirculated air while minimizing noise by optimizing airflow paths and using a housing design that reduces turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If recirculated air is used from the passenger compartment, then HVAC system efficiency is improved, but noise levels significantly increase
Solution Approach 1:
The air inlet is divided into multiple separate inlets: a first air inlet for recirculated air from the passenger compartment and a second air inlet for outside air. This segmentation allows independent control of each air source, enabling the system to optimize for efficiency by using recirculated air while managing noise through separate pathways and treatments for each inlet stream.
Solution Approach 2:
A valve with a blocking surface is introduced as an intermediary component to control and regulate the airflow from the first air inlet. The valve can be positioned to allow or block recirculated air, providing intermediate control states that balance efficiency and noise considerations by adjusting the mixture of recirculated and outside air based on operating conditions.
2Object-affected harmful factors
If a valve system is added to control airflow, then noise is reduced, but device complexity increases
Solution Approach 1:
The valve design applies local quality by positioning the blocking surface at a specific location within the housing to target noise reduction at the air inlet. The blocking surface is disposed radially outboard of the torque input, creating a localized control mechanism that addresses noise at its source without requiring complex systems throughout the entire HVAC assembly.
Solution Approach 2:
Instead of using complex active noise control systems or multiple moving parts, the invention uses a simple blocking surface that can be positioned to either allow or block airflow. This inverted approach—using a blocking mechanism rather than an active modulation system—reduces complexity while still achieving noise reduction through strategic placement and simple rotational movement.
Data Source
AI summary
An air intake system for a vehicle HVAC system is provided. The system includes a housing with air inlets and an outlet where air flows to a fan within an HVAC system. The air inlet comprising a first air inlet that is aligned to allow air to flow therethrough and into the inner volume from a passenger compartment of a vehicle and a second air inlet that is configured to allow air to flow into the inner volume from outside of a vehicle. A valve with a blocking surface that is movable with respect to the housing to allow or block air flow through a recirculating air inlet. The blocking surface receives torque from an input that is disposed radially outboard of the blocking surface.