Honeycomb Particulate Filter Catalysis for CO-Suppressed Exhaust Purification
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Solution Overview
Problem
Existing exhaust gas purification systems face challenges in meeting stringent PM emission regulations, particularly in Euro 7, where a PM collection rate of 95% or more is required, while also suppressing the emission of carbon monoxide (CO) due to incomplete combustion of PM in non-coating type filters.
Innovation Solution
An exhaust gas purification system with a three-way catalyst and particulate filter, controlled by a device that executes fuel cut during deceleration operations, utilizing a honeycomb substrate with outflow cell side catalyst layers to burn and convert CO into CO2, and a control method that adjusts throttle valve opening to optimize PM removal and catalyst protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a non-coating type filter is used to achieve high PM collection rate, then PM collection efficiency is improved, but CO emission increases due to incomplete combustion
Solution Approach 1:
The patent applies catalyst layers only in specific locations within the filter - on the outflow cell side and inflow cell side, rather than coating the entire filter surface. This localized catalyst placement enables CO oxidation at these specific zones while maintaining the high PM collection efficiency of the non-coating filter structure, thereby resolving the contradiction between PM collection rate and CO emission.
2Object-generated harmful factors
If a coating type filter is used to remove harmful components, then CO emission is reduced, but PM collection rate decreases
Solution Approach 1:
Instead of applying catalyst coating uniformly across the filter which would compromise PM collection efficiency, the patent strategically places catalyst layers only at the outflow and inflow cell sides. This localized approach provides CO oxidation capability where needed while preserving the high PM collection performance of the non-coating filter structure.
3Loss of substance
If fuel cut is executed during deceleration to reduce emissions, then fuel consumption is reduced, but CO emission increases due to PM combustion
Solution Approach 1:
The patent executes fuel cut in advance during deceleration operations, and the locally placed catalyst layers on the outflow and inflow cell sides are already positioned to handle the resulting CO from PM combustion. This preliminary catalyst placement ensures that when fuel cut is performed to reduce consumption, the CO emission is immediately managed by the pre-positioned catalysts.
4Power
If throttle valve opening is decreased to control air flow during deceleration, then engine load is reduced, but catalyst temperature decreases reducing combustion efficiency
Solution Approach 1:
The patent places catalyst layers specifically on the outflow and inflow cell sides where exhaust gas flow and temperature conditions are most favorable during deceleration. This localized placement ensures that even when overall catalyst temperature decreases due to reduced throttle opening, the PM combustion can still proceed effectively at these strategically positioned catalyst zones.
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 system effectively suppresses CO emissions by accelerating PM combustion and conversion into CO2, while minimizing catalyst deterioration, thus meeting stringent emission standards and ensuring efficient PM collection.
Implementation Method 1
an outflow cell side catalyst layer extending from an outflow side end of the partition wall to a position apart from the outflow side end toward an inflow side of the partition wall
Implementation Method 2
burn and convert CO into CO2
Implementation Method 3
When the exhaust gas passes through the partition wall, the PM is accumulated in pores present in the partition wall
Implementation Method 4
the PM is accumulated in pores present in the partition wall
Data Source
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AI summary
Provided is an exhaust gas purification system that allows suppressing the emission of carbon monoxide (CO). An exhaust gas purification system includes a three-way catalyst and a particulate filter and a control device. The three-way catalyst and the particulate filter are arranged respectively on an upstream side and a downstream side of an exhaust channel connected to an internal combustion engine. The control device controls the internal combustion engine so as to execute fuel cut during a deceleration operation of the internal combustion engine. The particulate filter includes a honeycomb substrate and an outflow cell side catalyst layer. The honeycomb substrate includes a porous partition wall defining a plurality of cells extending from an inflow side end surface to an outflow side end surface. The plurality of cells include an inflow cell and an outflow cell adjacent across the partition wall. The inflow cell has an open inflow side end and a sealed outflow side end. The outflow cell has a sealed inflow side end and an open outflow side end. The outflow cell side catalyst layer is disposed on an outflow cell side catalyst region extending from an outflow side end to a position apart toward an inflow side of the partition wall along an extending direction.