Catalyst Oxygen Storage Modulation for Richness Control

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Solution Overview

Problem

Existing methods for stimulating catalysts in internal combustion engines struggle to rapidly correct occasional richness accidents, leading to suboptimal pollutant conversion due to imbalances in oxygen storage and fuel mixture richness.

Innovation Solution

A method that modulates the richness setpoint in frequency and amplitude based on instantaneous oxygen storage levels, with thresholds adjusted according to exhaust flow rate, temperature, and engine operating point, forcing adjustments to decrease or increase oxygen storage when thresholds are reached, thereby correcting transient richness imbalances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If fixed thresholds for oxygen storage are used, then the control method is simple, but it cannot rapidly correct occasional richness accidents under varying operating conditions

Engineering Contradiction:

Improvecontrol method simplicityVSAvoidpollutant conversion efficiency

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies dynamics by making the thresholds dynamic rather than fixed. The thresholds are adapted in real-time based on exhaust flow rate and catalyst temperature, allowing the control system to respond effectively to varying operating conditions and correct richness accidents rapidly while maintaining simplicity in the control logic structure

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameters used for threshold determination from fixed values to variable parameters that depend on exhaust flow rate and catalyst temperature. This allows the control system to maintain reliable pollutant conversion efficiency across different operating conditions while keeping the control method straightforward

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If predetermined thresholds are used, then the system is easy to implement, but it fails to account for variations in exhaust flow rate and temperature

Engineering Contradiction:

Improvesystem implementation easeVSAvoidresponse to operating conditions

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent transforms predetermined fixed thresholds into dynamic thresholds that are functions of exhaust flow rate and catalyst temperature. This parameter change enables the system to adapt to varying operating conditions while maintaining ease of implementation through a straightforward control logic that simply adjusts thresholds based on measured parameters

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If rich/lean phases are activated at fixed oxygen levels, then the control logic is simple, but it does not optimize stimulation under different engine operating points

Engineering Contradiction:

Improvecontrol logic complexityVSAvoidcatalyst stimulation effectiveness

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent applies dynamics by making the control system adaptive to different engine operating points. The thresholds for activating rich/lean phases are dynamically adjusted based on exhaust flow rate and catalyst temperature, optimizing catalyst stimulation effectiveness across varying operating conditions while keeping the control logic relatively simple

Inventive Principle:

Principle #15Dynamics

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 effectively corrects occasional richness accidents, maintaining pollutant conversion efficiency close to that without disturbances, reducing the need for multiple engine settings and minimizing post-processing emissions and system costs.

Implementation Method 1

CO + 1/2 O2 -> CO2, CxHy + (x + y/4)O2 -> xCO2 + y/2 H2O

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

CO + NO -> CO2 + 1/2 N2

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 3

Another important characteristic of catalysts is their oxygen storage capacity or OSC. If this storage capacity is good, the catalyst absorbs the oxygen supplied to it in an appropriate manner.

Methodology Applied

Scientific EffectOxygen storage capacity: Absorption (physical)

Data Source

PatentEP2438285B1Method and system of a catalyst stimulation

Publication Date: 2020.11.25 PSA AUTOMOBILES SA

Figure 1~2
Figure 3

AI summary

The invention relates to a method for stimulating the catalytic converter of an internal combustion engine, and to a system for implementing said method. The invention is characterized in that it includes the following steps: estimating the instantaneous amount of oxygen stored in the catalytic converter (OS); and modulating the frequency and/or amplitude of the richness set value in accordance with said instantaneous amount of oxygen stored in the catalytic converter. The invention can in particular be used for petrol engines.