Catalyst Filter Uniformity Reduces Pressure Loss
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Solution Overview
Problem
The existing wall flow type particulate filters for gasoline engines have limitations in soot collection performance without increasing pressure loss due to the formation of the catalyst layer in the partition wall.
Innovation Solution
The solution involves adjusting the maldistribution degree and wash coat amount of the catalyst layer in the partition wall of the wall flow type substrate, ensuring an absolute maldistribution degree of 4.50 or less and a wash coat amount of 40 g/L to 50 g/L, using a single layer catalyst layer composed of Pd and/or Rh with Al oxide, Zr oxide, and/or Ce oxide as carrier components, and avoiding Ba, to enhance soot collection performance without increasing pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a catalyst layer is formed in the partition wall of a wall flow type substrate, then exhaust gas purification function is enhanced, but pressure loss increases
Solution Approach 1:
The invention optimizes the wash coat amount parameter to 40-50 g/L and controls the maldistribution degree to 4.50 or less, which changes the physical and chemical parameters of the catalyst layer formation process. This results in a catalyst layer with appropriate porosity and distribution that maintains purification function while minimizing pressure loss.
Solution Approach 2:
The invention focuses on creating a uniform catalyst layer distribution across the partition wall by controlling the maldistribution degree. This local quality control ensures that the catalyst layer has consistent properties throughout, optimizing both purification performance and pressure drop characteristics.
2Reliability
If the wash coat amount of the catalyst layer is increased, then soot collection performance is improved, but pressure loss increases
Solution Approach 1:
The invention identifies that increasing the wash coat amount beyond 50 g/L improves soot collection performance but also increases pressure loss. By optimizing the parameter to 40-50 g/L, the invention achieves the minimum effective wash coat amount for soot collection while preventing excessive pressure loss.
3Reliability
If the catalyst layer is formed with high maldistribution degree, then soot collection performance is improved, but pressure loss increases
Solution Approach 1:
The invention emphasizes uniform catalyst layer distribution by controlling the maldistribution degree to 4.50 or less. This local quality control ensures consistent catalyst properties across the partition wall, which optimizes both soot collection efficiency and pressure drop characteristics.
Solution Approach 2:
The invention optimizes the maldistribution degree parameter to 4.50 or less, which controls the uniformity of catalyst layer formation. This parameter control ensures that the catalyst layer has appropriate distribution characteristics that balance soot collection performance with pressure loss minimization.
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 results in improved soot collection performance and reduced pressure loss, enhancing the overall exhaust gas treatment system's efficiency.
Implementation Method 1
a catalyst layer formed in a pore of the partition wall
Implementation Method 2
a wall flow type substrate in which an introduction-side cell having an open exhaust gas introduction-side end, and a discharge-side cell adjacent to the introduction-side cell and having an open exhaust gas discharge-side end are defined by a porous partition wall
Data Source
AI summary
It is an object of the present invention to provide an exhaust gas purifying catalyst filter which has enhanced soot collection performance without increasing pressure loss caused by the formation of a catalyst layer in a partition wall of a wall flow type substrate.A gasoline engine exhaust gas purifying catalyst filter for purifying exhaust gas of a gasoline engine includes: a wall flow type substrate in which an introduction-side cell having an open exhaust gas introduction-side end, and a discharge-side cell adjacent to the introduction-side cell and having an open exhaust gas discharge-side end are defined by a porous partition wall; and a catalyst layer formed in a pore of the partition wall. An absolute value of a maldistribution degree of the catalyst layer formed in the pore of the partition wall is 4.50 or less. A wash coat amount, excluding a mass of a platinum group, of the catalyst layer formed in the pore of the partition wall, is 40 g/L or more and 50 g/L or less. The catalyst layer formed in the pore of the partition wall is a single layer. The catalyst layer is free of Ba.