Dual-Zone Exhaust Filter for Ash Management

Solution Overview

Problem

Existing exhaust purification filters face challenges in reliably trapping particulate matter while preventing pressure loss due to accumulating ash, as large diameter through holes allow significant particulate matter to escape during engine operation and PM removal processing.

Innovation Solution

The filter is designed with a fine zone and a rough zone in the partition walls, where the median micropore diameter of the rough zone allows ash to pass through, and the fine zone has coat layers with smaller micropores to trap particulate matter, along with promoting members that guide and enhance gas flow to prevent pressure loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If through holes are formed in downstream side plugs to enable ash to flow out, then pressure loss due to ash accumulation is reduced, but particulate matter flows out from the particulate filter through the through holes

Engineering Contradiction:

Improvepressure lossVSAvoidparticulate matter trapping efficiency

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The partition walls are divided into two distinct zones: a fine zone with small micropores (0.03-3 μm) for trapping particulate matter, and a rough zone with large micropores (3-30 μm) for allowing ash to pass through. This local differentiation of pore sizes enables simultaneous achievement of particulate matter filtration and ash discharge functions in different regions of the same partition wall structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The partition wall is segmented into functionally distinct regions (fine zone and rough zone) along the exhaust gas flow direction. The fine zone is positioned upstream to trap particulate matter, while the rough zone is positioned downstream to allow ash passage. This segmentation resolves the contradiction by assigning different filtration functions to different segments of the partition wall.

Inventive Principle:

Principle #1Segmentation

2Loss of energy

If large diameter through holes are used to discharge ash, then pressure loss is suppressed, but the amount of particulate matter flowing out is considerably large

Engineering Contradiction:

Improvepressure lossVSAvoidparticulate matter discharge

Core Design Contradiction:

Loss of energyVSLoss of substance

Solution Approach 1:

The partition walls are divided into two distinct zones: a fine zone with small micropores (0.03-3 μm) for trapping particulate matter, and a rough zone with large micropores (3-30 μm) for allowing ash to pass through. This local differentiation of pore sizes enables simultaneous achievement of particulate matter filtration and ash discharge functions in different regions of the same partition wall structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The partition wall is segmented into functionally distinct regions (fine zone and rough zone) along the exhaust gas flow direction. The fine zone is positioned upstream to trap particulate matter, while the rough zone is positioned downstream to allow ash passage. This segmentation resolves the contradiction by assigning different filtration functions to different segments of the partition wall.

Inventive Principle:

Principle #1Segmentation

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 design effectively traps particulate matter while suppressing pressure loss by allowing ash to be discharged, ensuring reliable filtration and maintaining engine output.

Implementation Method 1

a fine zone is defined at an upstream side of the partition walls and a rough zone is defined at a downstream side of the partition walls, a median micropore diameter of the partition walls in the rough zone is set larger than a median micropore diameter of the partition walls in the fine zone and is set so that ash which is contained in the exhaust gas can pass through the partition walls

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Implementation Method 2

in the fine zone, coat layers with a median micropore diameter smaller than the median micropore diameter of substrates of the partition walls cover the surfaces of the substrates

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS10294838B2Exhaust purification filter

Publication Date: 2019.05.21 TOYOTA JIDOSHA KK

AI summary

An exhaust cleaning filter has an exhaust gas inflow passage and an exhaust gas outflow passage disposed in alternating fashion; and a porous partition wall for setting the exhaust gas inflow and outflow passages at a distance from each other. A small pore region is sectioned off on the upstream side and a large pore region is sectioned off on the downstream side of the partition wall. The average pore diameter of the partition wall in the large pore region is greater than in the small pore region, and is set so that ash contained in the exhaust gas is able to pass through the partition wall. The exhaust purification filter has a promoting member for promoting the passing of exhaust gas that has flowed into the exhaust gas inflow passage, through the partition wall in the small pore region, and promoting inflow into the exhaust gas outflow passage.