Vehicle Cabin Air Filter Separation Efficiency Assessment

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Solution Overview

Problem

Current air filter control systems in vehicles lack an effective method to determine the optimal replacement time for cabin air filters, leading to either premature replacement with unnecessary costs or delayed replacement that compromises air quality due to the inability to accurately assess the filter's capacity to remove fine particles, particularly PM1, PM2.5, and PM10.

Innovation Solution

A method utilizing an aerosol generator to create a gas flow with fine particles of varying sizes, which is filtered through the existing air filter, and then using optical detection means to measure particle concentrations before and after filtration, calculating a separation efficiency rate to determine if the filter should be replaced based on real-time measurements and reference thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If regular replacement of air filter is performed based on fixed maintenance intervals, then cabin air quality is maintained, but unnecessary replacements occur generating additional costs for the end user

Engineering Contradiction:
Improvecabin air qualityVSAvoidunnecessary filter replacement costs
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent implements a feedback mechanism by continuously monitoring the actual filtration performance of the air filter using particle counters and aerosol generators. The system measures particle concentrations before and after the filter to calculate separation efficiency, providing real-time feedback on filter condition. This allows the system to determine the optimal replacement moment based on actual performance degradation rather than following fixed maintenance intervals, thus avoiding unnecessary replacements while ensuring cabin air quality.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system enables the air filter to essentially monitor its own condition through integrated sensors and measurement devices. The filter's effectiveness is self-assessed by measuring its ability to separate particles, allowing the vehicle to determine when replacement is truly necessary based on the filter's actual state rather than external scheduling, reducing unnecessary replacements.

Inventive Principle:
Principle #25Self-service

2Reliability

If air filter is replaced based on fixed maintenance intervals, then cabin air quality is maintained, but the replacement may occur before the filter actually deteriorates

Engineering Contradiction:
Improvecabin air qualityVSAvoidpremature replacement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical/time-based replacement system with an optical/electronic measurement system. Instead of relying on mileage-based or time-based schedules, the system uses particle counters, aerosol generators, and optical detection to continuously assess the filter's actual separation efficiency. This substitution allows replacement decisions to be based on real performance data rather than predetermined intervals, preventing premature replacements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system monitors changes in key performance parameters (particle separation efficiency, pressure differential) to determine filter condition. By tracking these parameter changes in real-time, the system can identify the actual moment when filter performance deteriorates below acceptable thresholds, rather than replacing based on fixed time or mileage parameters, thus avoiding premature replacement.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If visual examination of air filter is performed to assess filter condition, then replacement decision can be made, but the examination is delicate and often located in difficult to access mounting area

Engineering Contradiction:
Improvefilter condition assessmentVSAvoidfilter diagnostic tool
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary measurement system (aerosol generator and particle counter) that indirectly assesses filter condition without requiring direct visual inspection of the filter element. The intermediary devices measure particle concentrations in the air flow before and after the filter to calculate separation efficiency, providing an easy-to-obtain metric of filter health that avoids the complexity of physical inspection in difficult-to-access locations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces manual visual inspection with automated optical/electronic measurement systems. The particle counters and aerosol generators automatically assess filter condition through non-contact or minimal-contact measurements, eliminating the need for technicians to physically access and visually examine the filter in difficult-to-reach mounting areas, thus improving ease of operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If conventional pressure or flow rate monitoring is used to detect filter degradation, then clogging state can be precisely determined, but the method does not directly reflect alteration in capacity to block fine particles

Engineering Contradiction:
Improveclogging state detectionVSAvoidparticle blocking capacity assessment
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies local quality by specifically targeting the measurement of fine particle separation efficiency rather than general flow characteristics. The system uses particle counters to measure concentrations of specific particle size ranges (PM1, PM2.5, PM10) before and after the filter, providing localized information about the filter's ability to block fine particles. This complements or replaces broad pressure/flow measurements with targeted particle-specific measurements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes the measured parameter from general flow rate or pressure differential to specific particle separation efficiency. By measuring particle concentrations before and after the filter and calculating the reduction ratio, the system directly quantifies the filter's capacity to block fine particles, providing a more relevant and reliable indicator of actual filtration performance than conventional flow-based methods.

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 allows for reliable, real-time assessment of the filter's effectiveness in retaining fine particles, ensuring healthy cabin air quality by accurately determining when the filter needs to be replaced, thereby preventing health risks associated with particulate exposure.

Implementation Method 1

using an aerosol generator type diffuser making it possible to generate a gas flow loaded with fine particles of different sizes

Methodology Applied
Scientific EffectAerosol generation: Aerosol

Implementation Method 2

a particle filter, an odor filter or their combinations come into play to filter particles contained in the air

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 3

In ventilation ducts leading to an interior passenger compartment, impaction effects generally make it possible to limit the quantity of such particles

Methodology Applied
Scientific EffectImpaction: Impact Force

Implementation Method 4

carry out, using optical detection means, real-time measurements of particle concentrations as a function of their size distribution, in the collected fraction

Methodology Applied
Scientific EffectOptical detection:

Data Source

PatentEP3845404B1Method and device for controlling the condition of an air filter of a passenger compartment of a vehicle, by determining a barrier effect against fine particles
Publication Date: 2022.08.10 SOGEFI FILTRATION
  • EP3845404B1 patent drawingFigure 1~3
  • EP3845404B1 patent drawingFigure 4~5
  • EP3845404B1 patent drawing

AI summary

A removable air filtration filter element is being tested. A fine particulate matter concentration detection unit (C2) is placed in the vehicle's passenger compartment (8). The test comprises the following steps: - generating, via a diffuser (3), a gas stream (F) laden with fine particles outside the vehicle and directed towards a ventilation inlet (5); - performing optical detection by said unit (C2) to measure in real time (53) particle concentrations as a function of their size, in a fraction of the stream collected in the passenger compartment; - determining (54) a respective separation efficiency rate of the filter element with respect to PM1, PM2.5, and PM10 particles, using the measurements and reference information on the stream generated outside; and - developing and transmitting (55), at least in the event of a required change, a test result to a receiving terminal.