Engine Control Apparatus for Accurate Catalyst Diagnosis
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Solution Overview
Problem
Existing control apparatuses for internal combustion engines face challenges in accurately determining the deterioration of exhaust gas purification catalysts due to reduced accuracy in oxygen storage capacity calculations, especially when the wastegate valve is open, affecting the air-fuel ratio control and overall engine operation.
Innovation Solution
A control apparatus with an exhaust gas concentration parameter sensor, cylinder gas amount parameter acquisition unit, air-fuel ratio control unit, operation status determination unit, and determination value setting unit, which detects exhaust gas concentration downstream of the turbine, acquires cylinder gas amount, performs air-fuel ratio fluctuation control, and determines the engine's operation status by increasing the determination value as the wastegate valve opens, ensuring accurate detection even with reduced exhaust gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the wastegate valve is opened to control exhaust gas flow, then the turbine receives less exhaust gas and kinetic energy is reduced, but the exhaust gas concentration sensor detects reduced accuracy due to lower exhaust gas flow rate
Solution Approach 1:
The determination value for cylinder gas amount is dynamically adjusted based on the wastegate valve opening degree. As the wastegate valve opens larger, the determination value is set to a larger value, compensating for the reduced exhaust gas flow rate and maintaining accurate detection conditions even when turbine kinetic energy is reduced
Solution Approach 2:
The control apparatus continuously monitors the wastegate valve opening degree and adjusts the determination value accordingly. This feedback mechanism ensures that the cylinder gas amount determination remains accurate across varying operating conditions, particularly when the wastegate valve is opened to control exhaust gas flow
2Reliability
If the air-fuel ratio is fluctuated to determine catalyst deterioration, then the oxygen storage capacity can be calculated, but the determination accuracy is reduced when the wastegate valve is open due to lower exhaust gas flow
Solution Approach 1:
The determination value for cylinder gas amount is changed based on the wastegate valve opening degree. By setting a larger determination value when the wastegate valve is opened, the system maintains reliable catalyst deterioration determination even under conditions of reduced exhaust gas flow rate
3Ease of operation
If the wide-area air-fuel ratio sensor is used to detect pre-catalyst air-fuel ratio, then the air-fuel ratio can be controlled, but the sensor cannot accurately detect timing of change when the wastegate valve is opened
Solution Approach 1:
The cylinder gas amount determination acts as an intermediary condition to validate sensor readings. By checking whether the cylinder gas amount exceeds the determination value (which is adjusted based on wastegate valve opening), the system ensures that sensor detections are made under appropriate flow conditions, maintaining accurate timing detection
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 solution enhances the accuracy of determining the operation status and air-fuel ratio control, maintaining high determination accuracy even with large wastegate valve openings, thereby improving engine performance and merchantability.
Implementation Method 1
an exhaust gas concentration parameter sensor provided downstream of the turbine in the exhaust passage and detecting an exhaust gas concentration parameter indicating a concentration of a predetermined component, including oxygen, in the exhaust gas
Implementation Method 2
a turbocharger having a turbine provided in an exhaust passage, and a wastegate valve that changes kinetic energy received by the turbine from exhaust gas
Implementation Method 3
a wastegate valve that changes kinetic energy received by the turbine from exhaust gas by opening/closing a bypass passage for bypassing the turbine
Implementation Method 4
an air-fuel ratio control unit performing an air-fuel ratio fluctuation control process for controlling an air-fuel ratio of the internal combustion engine to fluctuate in a predetermined manner
Implementation Method 5
an exhaust gas purification catalyst that purifies exhaust gas flowing in the exhaust passage
Data Source
AI summary
A control apparatus for an internal combustion engine includes an exhaust gas concentration parameter sensor, a cylinder gas amount parameter acquisition device, an air-fuel ratio controller, an operation status determination device, and a determination value setting device. The air-fuel ratio controller is to perform an air-fuel ratio fluctuation control to control an air-fuel ratio in the internal combustion engine to fluctuate in a predetermined state. The operation status determination device is to determine an operation status of the internal combustion engine or an auxiliary device of the internal combustion engine based on an exhaust gas concentration parameter detected by the exhaust gas concentration parameter sensor in a case where an amount of a cylinder gas represented by a cylinder gas amount parameter acquired by the cylinder gas amount parameter acquisition device is equal to or larger than a predetermined determination value while the air-fuel ratio fluctuation control is being performed.