EGR Valve Flow Estimation via Manifold Oxygen Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for estimating the EGR rate in internal combustion engines face accuracy issues due to individual differences and aging changes in the flow characteristic of the EGR valve, leading to deteriorated estimation of the recirculation exhaust gas flow rate.
Innovation Solution
A controller and control method that detect inner-manifold oxygen concentration and intake air flow rate to calculate an oxygen concentration detecting EGR rate, which is used to learn the opening area of the EGR valve, thereby improving the estimation accuracy of the recirculation exhaust gas flow rate by minimizing the influence of individual differences and aging changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the flow characteristic of the EGR valve is used to estimate the recirculation exhaust gas flow rate, then the estimation can be performed based on valve opening area, but individual differences and aging changes cause deterioration of estimation accuracy
Solution Approach 1:
The patent applies feedback by using the detected inner-manifold oxygen concentration to continuously correct and update the EGR rate estimation. The controller detects actual oxygen concentration in the intake manifold and compares it with expected values to calculate the actual EGR rate, thereby compensating for individual differences and aging changes in the EGR valve flow characteristic.
Solution Approach 2:
The patent replaces reliance on mechanical flow characteristic data of the EGR valve with an oxygen concentration-based detection method. Instead of using the EGR valve's flow characteristic curve (which degrades over time), the system uses electrochemical oxygen sensor detection to directly measure the EGR rate, substituting a chemical sensing approach for a mechanical modeling approach.
2Measurement precision
If the EGR valve flow characteristic is learned to improve estimation accuracy, then individual differences can be compensated, but response delay occurs due to the mixing time in the intake manifold
Solution Approach 1:
The patent applies preliminary action by detecting the oxygen concentration in the intake manifold before combustion occurs. This allows the EGR rate to be estimated based on the composition of the air-exhaust gas mixture that will be combusted, providing advance information about the actual EGR rate before the combustion process alters the gas composition.
3Measurement precision
If the oxygen concentration in the intake manifold is used to calculate the EGR rate, then individual differences and aging changes are minimized, but response delay occurs due to gas mixing time
Solution Approach 1:
The patent uses the oxygen concentration detection as a representative copy of the EGR rate condition. Instead of directly measuring the exhaust gas flow rate, the system measures the oxygen concentration in the mixed gas, which serves as a proxy or copy that reflects the EGR rate while being obtained through a more reliable and stable measurement method.
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 proposed solution enhances the estimation accuracy of the recirculation exhaust gas flow rate by learning the EGR valve's opening area, reducing response delays and improving control accuracy for internal combustion engines.
Implementation Method 1
an oxygen concentration sensor 10 that outputs an electric signal according to inner-manifold oxygen concentration
Data Source
AI summary
To provide a controller and a control method for an internal combustion engine capable of learning the individual difference and the aging change of the flow characteristic of the EGR valve, by a method which is hardly influenced by the individual difference and the aging change of the internal combustion engine body, and improving the estimation accuracy of the flow rate of recirculation exhaust gas. The controller for an internal combustion engine calculates an oxygen concentration detecting EGR rate Regr based on the inner-manifold oxygen concentration; calculates an oxygen concentration detecting recirculation flow rate based on the oxygen concentration detecting EGR rate and the intake air flow rate, and calculates a learning value of the opening area of EGR valve; and calculates a flow rate of recirculation exhaust gas for control based on the learned opening area.