Multi-Cylinder Engine Controller Cylinder Fuel Cutoff Anomaly Detection
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Solution Overview
Problem
Existing controllers for multi-cylinder internal combustion engines face challenges in accurately detecting anomalies during cylinder deactivation due to errors in exhaust gas detection values caused by the shape of the exhaust pipe and the relative position of the exhaust sensor, leading to incorrect determination of fuel cutoff anomalies.
Innovation Solution
A controller that uses an upstream oxygen sensor to compare detection values from different cylinder groups, performing specific cylinder fuel cutoff control and anomaly determination by selecting a cutoff cylinder based on intake air amount and adjusting fuel supply to reduce detection value discrepancies and prevent false anomaly detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an exhaust sensor is used to detect oxygen from deactivated cylinders, then anomaly detection capability is improved, but detection precision deteriorates due to exhaust pipe shape and sensor position causing errors
Solution Approach 1:
The patent segments the cylinders into two groups: a first cylinder group whose exhaust gas detection values are used for anomaly detection, and a second cylinder group that is excluded from detection. This segmentation allows the system to avoid using detection values from cylinders that would produce erroneous readings due to exhaust pipe shape and sensor position, thereby resolving the contradiction between anomaly detection capability and measurement precision.
Solution Approach 2:
The patent extracts and excludes the second cylinder group from the anomaly detection process. By taking out the cylinders that cause detection errors due to their specific exhaust pipe configuration and sensor position, the system maintains reliable anomaly detection while avoiding imprecise measurements from problematic cylinders.
2Reliability
If fuel supply is cut off to specific cylinders for catalyst oxygen supply, then catalyst performance is improved, but false anomaly detection increases due to detection value errors
Solution Approach 1:
The patent segments cylinders into those suitable for fuel cutoff (first cylinder group) and those unsuitable for detection purposes (second cylinder group). By performing fuel cutoff on cylinders from the first group and using only their detection values for anomaly determination, the system ensures both effective catalyst oxygen supply and accurate anomaly detection without false positives.
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors exhaust gas detection values and compares them against expected ranges. When fuel cutoff is performed on a cylinder from the first group, the system expects a specific detection value pattern; deviations from this pattern trigger anomaly determination. This feedback loop ensures reliable catalyst oxygen supply while preventing false anomaly 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 ensures accurate anomaly determination and reduces the likelihood of incorrect fuel cutoff anomalies by selecting cylinders with higher detection values for cutoff, maintaining engine efficiency and catalyst oxygen supply.
Implementation Method 1
an exhaust sensor that detects oxygen and is arranged at an upstream side of a catalyst in an exhaust passage
Data Source
AI summary
When an intake air amount is greater than or equal to the lower limit intake air amount and less than or equal to the upper limit intake air amount, a CPU sets, from the first cylinder group that increases a detection value of an upstream air-fuel ratio sensor, one of cylinders that has the smallest cutoff frequency, which is stored in a storage device, as a cylinder to which the supply of fuel will be cut off. Then, the CPU obtains the maximum value of an upstream air-fuel ratio as a maximum air-fuel ratio. When the maximum air-fuel ratio is greater than a determination value, the CPU determines that specific cylinder fuel cutoff control is normal. When the maximum air-fuel ratio is less than or equal to the determination value, the CPU determines that the specific cylinder fuel cutoff control is anomalous.