Exhaust Purification System with Optimized OSC Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing exhaust gas purification systems for gasoline engines face challenges in efficiently removing NOx, hydrocarbons, carbon monoxide, and particulate matter, especially soot, while maintaining high engine performance and low carbon dioxide emissions, especially under varying operating conditions and during real driving emissions tests.
Innovation Solution
An exhaust gas purification system comprising a first three-way-catalyst (TWC1) upstream of a gasoline particulate filter (GPF), followed by a second three-way-catalyst (TWC2), where the oxygen storage capacity of TWC2 is greater than that of the GPF, and TWC1 has a higher volume and oxygen storage capacity than TWC2, optimizing the distribution of platinum-group metals and wash coat loads to achieve efficient pollutant removal and low pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If more catalyst material and filtration means are required to increase filtration efficiency or catalytic activity, then the efficiency of the gasoline engine is reduced and more carbon dioxide is emitted
Solution Approach 1:
The patent applies parameter changes by optimizing the oxygen storage capacity distribution among different catalyst devices. Specifically, the first TWC is positioned close to the engine with moderate OSC, the GPF is positioned downstream with higher OSC for soot oxidation, and a second TWC is positioned furthest downstream with the highest OSC to handle regeneration emissions. This spatial and functional parameter optimization allows efficient pollutant removal without excessive catalyst material, thereby reducing engine performance loss and CO2 emissions.
2Object-generated harmful factors
If the pressure drop is kept low, then it is difficult to achieve a good filtration efficiency and high catalytic activity in the limited space of the exhaust gas purification system
Solution Approach 1:
The patent applies segmentation by dividing the exhaust gas purification system into multiple distinct devices positioned in sequence: a first TWC close to the engine, a GPF downstream, and a second TWC furthest downstream. Each device has optimized characteristics for its specific function and position. This segmentation allows each component to operate at optimal pressure drop levels for its purpose, preventing excessive backpressure on the engine while achieving high overall filtration and catalytic efficiency through the combined system.
3Temperature
If a GPF and catalytic devices are operated close to the engine to require high temperatures for efficient operation, then dimensional limitations of the overall exhaust gas purification system are imposed
Solution Approach 1:
The patent applies dimensional optimization by arranging catalyst devices at different downstream positions along the exhaust flow path. The first TWC is positioned close to the engine (short distance), the GPF is positioned downstream (medium distance), and the second TWC is positioned furthest downstream (long distance). This spatial arrangement in the downstream dimension allows each device to operate at appropriate temperatures for its function while managing overall system dimensions efficiently, with downstream devices experiencing progressively lower temperatures suitable for their specific catalytic activities.
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 enables high-efficiency removal of gaseous and particulate pollutants, maintains engine performance, and reduces carbon dioxide emissions, with improved catalytic activity and filtration efficiency, even under non-optimal conditions, and supports efficient regeneration of the GPF.
Implementation Method 1
a first three-way-catalyst (TWC1), a gasoline particulate filter (GPF) and a second three-way-catalyst (TWC2)... High catalytic activity is required for efficient depletion of gaseous pollutants, such as HC, NOx and CO
Implementation Method 2
The most relevant pollutants in this regard are nitrogen oxides (NOx), hydrocarbons (HC or THC), carbon monoxide (CO)... such gaseous pollutants are removed from the exhaust gas by catalyst system
Implementation Method 3
a first three-way-catalyst (TWC1)... capable of removing nitric oxides, hydrocarbons and carbon monoxide
Implementation Method 4
High filtration efficiency is required for efficient removal of particles... the GPF should efficiently reduce the particle mass (PM) and the particle number (PN) of the exhaust gas
Implementation Method 5
The GPF should efficiently reduce the particle mass (PM) and the particle number (PN) of the exhaust gas
Implementation Method 6
the oxygen storage capacity (OSC) of the TWC2 is greater than the OSC of the GPF, wherein the OSC is determined in mg/l of the volume of the device... High catalytic activity is required for efficient depletion of gaseous pollutants
Implementation Method 7
a gasoline engine should have low fuel consumption in order to keep carbon dioxide emissions low... GPF and catalytic devices require high temperatures for efficient operation
Data Source
AI summary
Described is an exhaust gas purification system for a gasoline engine, comprising in consecutive order the following devices: a first three-way-catalyst (TWC1), a gasoline particulate filter (GPF) and a second three-way-catalyst (TWC2), wherein the oxygen storage capacity (OSC) of the TWC2 is greater than the OSC of the GPF, wherein the OSC is determined in mg/l of the volume of the device.