Vehicle Cabin Vent Control for Overpressure in Recirculation

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Solution Overview

Problem

Existing vehicle air-conditioning systems struggle to maintain optimal air quality by achieving overpressure in the vehicle interior independently of fresh air supply, especially in recirculation mode, leading to potential contamination through leakage points.

Innovation Solution

The system controls the flow resistance of the interior ventilation device using a final control element, which can be mechanically coupled to a fresh air/recirculated air flap or actuated by an actuator, to create overpressure relative to the ambient environment, allowing for improved air quality without excessive fan output and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If fan output is increased to achieve overpressure in the vehicle interior, then interior pressure is improved, but noise level increases

Engineering Contradiction:

Improveinterior pressureVSAvoidnoise level

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

The invention changes the flow resistance parameter of the interior ventilation device by adjusting the ventilation flap position. This allows overpressure to be achieved at low fan outputs by restricting the exhaust air flow path, thereby avoiding the need to increase fan output and the associated noise increase.

Inventive Principle:

Principle #35Parameter changes

2Stress or pressure

If fresh air supply is increased to achieve overpressure in the vehicle interior, then interior pressure is improved, but filter load increases

Engineering Contradiction:

Improveinterior pressureVSAvoidfilter load

Core Design Contradiction:

Stress or pressureVSLoss of substance

Solution Approach 1:

The invention changes the flow resistance parameter of the interior ventilation device by adjusting the ventilation flap position. This allows overpressure to be achieved by restricting exhaust flow rather than increasing fresh air supply, thereby reducing the load on the air filter.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If recirculation mode is used to prevent air pollution in the vehicle interior, then air quality is improved, but interior pressure control becomes difficult

Engineering Contradiction:

Improveair pollutionVSAvoidinterior pressure

Core Design Contradiction:

Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The ventilation flap is designed to be automatically actuated by the pressure difference between the vehicle interior and exterior. When recirculation mode is active and the interior pressure rises slightly, the pressure differential automatically adjusts the flap position to restrict exhaust flow, thereby maintaining overpressure without requiring additional control mechanisms.

Inventive Principle:

Principle #25Self-service

4Object-affected harmful factors

If ventilation flap is arranged in the flow path to prevent unfiltered air backflow, then air quality is improved, but pressure increase capability is limited

Engineering Contradiction:

Improveunfiltered air backflowVSAvoidinterior pressure

Core Design Contradiction:

Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The invention utilizes the ventilation flap to dynamically change the flow resistance parameter of the interior ventilation device. By adjusting the flap position, the system can restrict exhaust air flow to achieve overpressure while simultaneously preventing unfiltered air backflow when the flap closes in response to pressure differential or control signals.

Inventive Principle:

Principle #35Parameter changes

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 maintains superior air quality by ensuring overpressure in the vehicle interior, reducing unfiltered air entry and filter load, while allowing for efficient recirculation and rapid temperature adjustments, even at low fan outputs, thus enhancing interior cleanliness and energy efficiency.

Implementation Method 1

the pressure in the vehicle interior would therefore have to be greater than the pressure outside the vehicle interior

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

filter devices are used for filtering and purifying at least the fresh air supplied to the vehicle interior

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Implementation Method 3

varying the flow resistance of an interior ventilation device for conducting air out of the vehicle interior

Methodology Applied

Scientific EffectFlow resistance: Drag

Data Source

PatentUS11787266B2Vehicle air-conditioning system for ventilating a vehicle interior compartment

Publication Date: 2023.10.17 MERCEDES BENZ GROUP AG

AI summary

A system for ventilating a vehicle interior compartment operates, at least intermittently, to set an air quality mode in which fresh air and/or circulated air is supplied to the vehicle interior compartment, and to control an interior compartment pressure in the vehicle interior compartment through variation of the flow resistance of an interior compartment ventilation device in an open-loop and/or a closed-loop manner such that the interior compartment pressure is higher than an ambient pressure outside the vehicle interior compartment.