Ionized Electret Air Filter Layout for Low Pressure Drop
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Solution Overview
Problem
Existing air filter units for vehicles face challenges in achieving high particle separation efficiency while maintaining low flow resistance and pressure drop over the filter's lifetime, especially in polluted urban areas.
Innovation Solution
The air filter unit incorporates an ionization unit with a corona discharge electrode and a counter-electrode, combined with a filter medium that includes an electret layer, a mechanically separating layer, and an electrically conductive layer, ensuring effective particle separation and low flow resistance throughout its service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a filter element with a fibrous filter layer is used to separate particles, then particle separation efficiency is improved, but flow resistance and pressure drop increase
Solution Approach 1:
The filter element uses a porous fibrous filter layer with carefully controlled porosity to achieve particle separation while maintaining adequate airflow. The porous structure allows air to pass through while capturing particles, balancing filtration efficiency with flow resistance.
Solution Approach 2:
The filter element combines multiple materials including fibrous filter media and electrostatically charged materials to create a composite structure that enhances both particle separation efficiency and airflow characteristics through the synergistic effect of different materials.
2Productivity
If the filter layer is made very porous to ensure adequate airflow, then flow resistance is reduced, but mechanical dust separation efficiency decreases
Solution Approach 1:
The filter element introduces electrostatically charged particles or surfaces as an intermediary mechanism to enhance dust separation. This electrostatic attraction works in conjunction with the porous structure, allowing the filter to capture dust particles effectively even with higher porosity that maintains good airflow.
3Manufacturing precision
If electrostatically charged filter media are used to attract dust particles, then particle separation efficiency is improved, but the electrostatic charge decreases with aging and dust exposure
Solution Approach 1:
The filter element is pre-charged electrostatically during the manufacturing process to provide immediate particle separation capability. This preliminary electrostatic charging ensures high filtration efficiency from the beginning of service, though the charge gradually decreases over time with use.
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 configuration maintains a high particle separation efficiency over the entire lifetime of the filter medium, reducing the particle load for vehicle occupants while maintaining a low pressure drop, comparable to conventional cabin air filters.
Implementation Method 1
the at least one ionization unit has at least one corona discharge electrode
Implementation Method 2
filter media that attract electrostatically charged particles
Data Source
AI summary
An air filter unit may include at least one ionization unit and at least one filter medium arranged downstream of the ionization unit. The ionization unit may include at least one corona discharge electrode, at least one counter-electrode, and at least one voltage source. The at least one filter medium may include at least one electret layer, at least one mechanically separating layer, and at least one electrically conductive layer adjoining the mechanically separating layer. In an airflow direction extending from an inflow side toward an outflow side, the electret layer, the mechanically separating layer, and the electrically conductive layer may be arranged one after another in this order.