Catalyst Diagnosis Integrator Holding Values Across Intermittent Conditions
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Solution Overview
Problem
Existing catalyst deterioration diagnosis systems fail to accurately diagnose catalyst deterioration in situations where the required diagnosis conditions are not met within the necessary time period, often due to factors like traffic congestion or frequent accelerator pedal operations.
Innovation Solution
A catalyst deterioration diagnosis apparatus that includes upstream and downstream air-fuel ratio detectors, an integrator for calculating output variation integrated values, and a determiner that assesses catalyst deterioration based on thresholds, with the ability to hold and resume integration values when diagnosis conditions are unsatisfied, allowing for diagnosis across multiple cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the diagnosis running condition is required to be satisfied continuously for a predetermined time period to execute catalyst deterioration diagnosis, then the diagnosis accuracy is improved, but the diagnosis frequency becomes insufficient when traffic congestion or frequent accelerator operations occur
Solution Approach 1:
The system performs preliminary integration of air-fuel ratio output variations during periods when diagnosis conditions are satisfied, storing the integrated values. When conditions become unsatisfied and later resume, the previously stored integrated values are retained and continued from, rather than restarting integration. This preliminary accumulation of data during favorable conditions enables accurate diagnosis even when conditions are not continuously satisfied for the full required period.
2Device complexity
If the integration of output variation is restarted when diagnosis condition becomes unsatisfied, then the integration process is simplified, but the diagnosis accuracy deteriorates due to loss of accumulated data
Solution Approach 1:
The integration of air-fuel ratio output variations continues without interruption even when diagnosis conditions become unsatisfied. The system maintains cumulative integration values in memory throughout periods when conditions are not met, and resumes integration from these stored values when conditions are satisfied again. This continuous accumulation preserves all useful data while simplifying the overall process by eliminating the need to restart integration.
3Reliability
If the diagnosis requires a fixed time period with continuous satisfaction of running conditions, then the diagnosis reliability is improved, but the adaptability to real-world driving conditions deteriorates
Solution Approach 1:
The diagnosis system dynamically adapts to varying driving conditions by flexibly accumulating integration data over multiple separate periods rather than requiring continuous satisfaction of conditions for a fixed duration. The system can accumulate sufficient integration values through multiple shorter intervals, making it adaptable to real-world scenarios like traffic congestion or frequent accelerator operations while maintaining diagnosis reliability through adequate data accumulation.
Data Source
AI summary
A catalyst deterioration diagnosis apparatus includes an upstream side air-fuel ratio detector, a downstream side air-fuel ratio detector, an air-fuel ratio variation integrator that integrates the output variations of the respective air-fuel ratio detectors when a diagnosis running condition is satisfied, and a determiner that determines catalyst deterioration when the output variation integrated value of the upstream side air-fuel ratio detector exceeds a predetermined integration ending threshold, and further when a ratio between the output variation integrated value of the two detectors exceeds a predetermined determination threshold. The air-fuel ratio variation integrator holds the integrated values when the diagnosis running condition becomes unsatisfied before the integrated value of the upstream side air-fuel ratio detector reaches the integration ending threshold. The air-fuel ratio variation integrator resumes the integration using the held values as initial values when the diagnosis running condition is satisfied later again.