Engine Controller Oxygen Capacity Estimation
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Solution Overview
Problem
Existing methods for calculating the stored oxygen capacity of a catalytic converter in internal combustion engines, such as through lean combustion, adversely affect exhaust gas properties and reduce fuel efficiency due to the need for motoring control to supply oxygen to the catalytic converter.
Innovation Solution
A controller executes a richening process to deplete the catalytic converter's oxygen, followed by an air supplying process that stops fuel to specific cylinders and maintains stoichiometric combustion in others, allowing the catalytic converter to be supplied with air without lean combustion, thereby estimating the stored oxygen capacity without affecting exhaust gas properties or fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lean combustion is performed to supply oxygen to the catalytic converter, then the stored oxygen capacity can be calculated, but exhaust gas properties are adversely affected and fuel efficiency is reduced
Solution Approach 1:
The invention divides the engine cylinders into two groups: a first plurality of cylinders that perform lean combustion to supply oxygen to the catalytic converter, and a second plurality of cylinders that perform rich combustion to maintain overall exhaust gas properties. This segmentation allows simultaneous achievement of oxygen supply for capacity calculation and preservation of exhaust gas quality.
2Measurement precision
If motoring control is executed to supply oxygen to the catalytic converter, then the stored oxygen capacity can be calculated, but battery electric power is consumed and fuel efficiency is lowered
Solution Approach 1:
The invention enables the engine to supply oxygen to the catalytic converter through lean combustion in selected cylinders, using the engine's own combustion process rather than external battery power. This self-service approach eliminates the need for motoring control and battery discharge, thereby maintaining fuel efficiency while achieving accurate stored oxygen capacity calculation.
3Quantity of substance
If fuel is stopped to all cylinders for motoring control, then oxygen can be supplied to the catalytic converter, but the internal combustion engine cannot generate power
Solution Approach 1:
The invention segments the cylinder group into first plurality of cylinders that stop fuel supply to provide oxygen-rich exhaust to the catalytic converter, and second plurality of cylinders that continue combustion to maintain engine power output. This segmentation resolves the contradiction between oxygen supply and power generation by ensuring that not all cylinders stop combustion.
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 method allows for accurate estimation of the catalytic converter's stored oxygen capacity without harming exhaust gas properties or fuel efficiency, as it uses the engine's energy to supply air instead of relying on battery power for motoring control, and provides efficient operation by determining catalytic converter functionality and sensor responsiveness.
Implementation Method 1
a catalytic converter configured to purify exhaust gas and configured to store oxygen
Implementation Method 2
an exhaust sensor located at a downstream side of the catalytic converter and configured to detect oxygen
Implementation Method 3
performing combustion at an air-fuel ratio that is less than or equal to a stoichiometric air-fuel ratio in remaining one or more of the cylinders
Data Source
AI summary
A controller for an internal combustion engine includes processing circuitry that executes a richening process until an exhaust sensor detects exhaust gas having a rich air-fuel ratio. The processing circuitry executes an air supplying process to supply a catalytic converter with air until the exhaust sensor detects that the exhaust gas has a lean air-fuel ratio. The processing circuitry cumulates the amount of air supplied to the catalytic converter until the exhaust sensor detects that the exhaust gas has a lean air-fuel ratio in the air supplying process. The air supplying process includes stopping fuel supplied to the one or more of the cylinders and performing combustion at an air-fuel ratio that is less than or equal to the stoichiometric air-fuel ratio in the remaining one or more of the cylinders.