Engine Controller Exhaust Pressure Rate Stabilization
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Solution Overview
Problem
Internal combustion engines face unstable exhaust pressure readings due to fluctuations in intake air amount and particulate matter deposition, leading to unstable engine control.
Innovation Solution
A controller system that calculates and maintains a specific exhaust pressure rate by using a reference filter with a specified particulate matter deposition amount, incorporating an intake flow rate sensor and pressure sensors to stabilize exhaust pressure readings during engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exhaust pressure is used for engine control, then engine control can be performed based on exhaust pressure, but the exhaust pressure values fluctuate and are unstable during engine operation
Solution Approach 1:
The patent introduces an intermediary calculation process that uses intake air amount as a reference parameter to normalize exhaust pressure readings. By calculating the ratio of actual exhaust pressure to reference exhaust pressure at the same intake air amount, the system mediates between the fluctuating exhaust pressure and the need for stable control values, eliminating instability caused by intake air variations
Solution Approach 2:
The patent transforms the raw exhaust pressure parameter into a normalized parameter (exhaust pressure ratio) by comparing it against reference values at matching intake air amounts. This parameter transformation changes the exhaust pressure from an absolute value subject to fluctuations into a relative value that compensates for intake air variations, achieving stable readings for control purposes
2Measurement precision
If exhaust pressure increases due to particulate matter deposition in the filter, then the degree of clogging can be indicated, but the exhaust pressure also increases with intake air amount making it difficult to distinguish the cause
Solution Approach 1:
The patent implements a feedback mechanism where the intake air amount (from the air model or sensor) is continuously monitored and used to select appropriate reference exhaust pressure values. This feedback loop allows the system to dynamically adjust the comparison baseline, enabling accurate distinction between pressure increases caused by clogging versus those caused by intake air variations
Solution Approach 2:
The patent performs preliminary establishment of reference exhaust pressure values at different intake air amounts (creating the air model). This preliminary action stores the relationship between intake air and exhaust pressure under normal conditions, allowing the system to later compare actual readings against these pre-established references to accurately determine clogging without complex real-time analysis
Data Source
AI summary
A controller is configured to perform a process of obtaining an exhaust pressure upstream of a filter inside an exhaust passage and an intake air amount detected by an air flowmeter, when the filter in which a deposition amount of particulate matter is a specified amount is referred to as a reference filter, a calculation process of calculating an exhaust pressure rate that indicates a ratio of the obtained exhaust pressure to an exhaust pressure at the reference filter for the obtained intake air amount, and a setting process of setting the exhaust pressure rate that is maintained at a specific value during engine operation.