Plugged Honeycomb Structure Thermal Shock Resistance
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Solution Overview
Problem
The frequent reduction in regeneration frequency of diesel particulate filters (DPFs) leads to increased soot deposition, causing thermal shock and potential damage due to temperature rises, which existing materials fail to adequately mitigate, resulting in compromised fuel efficiency and filter durability.
Innovation Solution
A plugged honeycomb structure with porous partition walls composed of a porous body including α-Al2O3 as a main phase, combined with aluminum titanate and glass, offering enhanced heat capacity and thermal shock resistance, thereby inhibiting temperature rises during high-temperature use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the number of regeneration cycles is decreased to improve fuel efficiency, then fuel consumption is reduced, but thermal shock damage increases due to larger temperature rises from accumulated soot burning
Solution Approach 1:
The patent changes the thermal parameters of the partition wall material by using a porous body with specific heat capacity between 2.0 to 4.0 J/cm³K and thermal conductivity between 0.5 to 2.0 W/mK. This parameter optimization allows the material to accumulate less heat during soot combustion, reducing temperature rises to 800°C or below even during infrequent regeneration cycles, thereby preventing thermal shock damage while maintaining fuel efficiency
Solution Approach 2:
The patent employs a composite porous body structure combining materials with complementary properties: α-Al2O3 (40-70 mass%) provides high temperature stability, aluminum titanate (10-50 mass%) contributes to low thermal conductivity and appropriate heat capacity, and glass phase (5-30 mass%) fills pores to optimize thermal properties. This composite structure achieves the desired balance between heat capacity and thermal conductivity to mitigate thermal shock during extended operation between regenerations
2Object-affected harmful factors
If the heat capacity of the porous body is increased to reduce temperature rise, then thermal shock resistance is improved, but the material composition becomes more complex
Solution Approach 1:
The patent establishes specific parameter ranges for the porous body: heat capacity of 2.0 to 4.0 J/cm³K and thermal conductivity of 0.5 to 2.0 W/mK. These quantified parameters provide clear design targets that balance temperature rise control with material simplicity, enabling manufacturers to select from various porous body types (ceramic foams, extruded structures, molded bodies) that meet these specifications without requiring overly complex compositions
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
The structure effectively reduces thermal shock damage and maintains fuel efficiency by providing a higher heat capacity per unit volume, allowing for fewer regeneration cycles without compromising filter integrity.
Implementation Method 1
a heat capacity C represented by a product of specific heat c (kJ/kg·K) and a specific gravity ρ (kg/m3) is from 400.0 to 2000.0 (kJ/m3·K)
Implementation Method 2
a thermal conductivity κ is from 1.0 to 30.0 (W/m·K)
Data Source
AI summary
There is disclosed a plugged honeycomb structure. A plugged honeycomb structure includes a pillar-shaped honeycomb structure body having porous partition walls defining a plurality of cells which become through channels for a fluid and extend from a first end face to a second end face, and plugging portions disposed in open ends of predetermined cells in the first end face and open ends of residual cells in the second end face, and the partition walls are constituted of a porous body including α-Al2O3 as a main phase and further including aluminum titanate and glass.