Engine Controller Intake Air Pulsation Detection
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Solution Overview
Problem
Existing engine control methods fail to accurately detect intake air pulsation, leading to errors in calculating the intake air amount, especially in engines operating in Atkinson cycle, where intake air flows backward, causing detection errors in air flow meters and reducing control accuracy.
Innovation Solution
An engine controller that determines intake air pulsation by calculating the difference between the average and minimum intake air flow rates, switching between mass flow and speed density/throttle speed methods based on pulsation magnitude, using the bottom-side half amplitude of the flow rate to accurately assess pulsation and adjust calculation methods accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the mass flow method is used to calculate intake air amount, then calculation accuracy is improved during steady operation, but detection accuracy deteriorates when intake air pulsation is great
Solution Approach 1:
The system dynamically switches between mass flow method and speed density method based on real-time detection of intake air pulsation magnitude. When pulsation is detected to be great, the calculation method is switched to speed density method; when pulsation is small, mass flow method is used. This dynamic adaptation resolves the contradiction between accuracy under steady conditions and reliability under pulsation conditions.
Solution Approach 2:
The system changes the calculation parameter selection based on pulsation magnitude. By monitoring pulsation parameters (flow rate variations) and switching between different calculation methods (mass flow vs. speed density), the system adapts to different operating conditions, maintaining both accuracy and reliability across varying engine states.
2Productivity
If the air flow meter detection result is used, then calculation speed is improved, but measurement precision deteriorates in backward flow ranges
Solution Approach 1:
The system introduces an intermediary evaluation mechanism that assesses pulsation magnitude before relying on air flow meter data. By first evaluating whether pulsation is great using the air flow meter's own output, the system can determine whether to trust the mass flow calculation or switch to speed density method, thus protecting against precision errors in backward flow ranges while maintaining calculation efficiency when conditions are favorable.
Solution Approach 2:
The system uses feedback from the air flow meter detection results to evaluate pulsation magnitude and determine whether to proceed with mass flow calculation or switch methods. This feedback loop allows the system to maintain high calculation speed when detection is reliable while preventing precision errors when backward flow occurs, thus resolving the contradiction between productivity and measurement precision.
3Reliability
If calculation method switching is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The control system is designed with multi-functionality to handle both pulsation evaluation and calculation method selection using existing sensors and processing capabilities. The air flow meter and control unit perform multiple functions: detecting flow rate, evaluating pulsation magnitude, and selecting appropriate calculation methods. This universal approach improves reliability without proportionally increasing device complexity.
Solution Approach 2:
The system performs preliminary evaluation of pulsation magnitude using the air flow meter detection results before committing to a specific calculation method. By preparing the pulsation evaluation in advance and establishing clear switching criteria, the system simplifies the overall control logic and reduces the complexity burden, while still achieving improved reliability through method switching.
Data Source
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AI summary
An engine controller, an engine control method, and memory medium are provided. A second calculation process (P2) calculates an intake air amount without using a detection result of an air flow meter (13). The determination process (P3) determines that intake air pulsation is great if it is confirmed that a difference between an average flow rate (GAVE) and a minimum flow rate (GMIN) is great. The average flow rate (GAVE) is an average value of an intake air flow rate within a period (TO) of the intake air pulsation. The minimum flow rate (GMIN) is a minimum value of the intake air flow rate within the period (TO). When it is determined that the intake air pulsation is great, a calculation method switching process (P4) selects a calculated value (MC2) of the intake air amount that is obtained by the second calculation process (P2).