Air Mass Flow Substitution in Supercharged Engines
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Solution Overview
Problem
In supercharged internal combustion engines, existing air mass flow sensors face interference and inaccuracies during high boost pressure and low air mass flow conditions, leading to erroneous measurements and control issues, particularly during rapid load changes and compressor pumping, where the air mass flow sensor is not designed to accurately detect reverse air flows.
Innovation Solution
A method and device that utilize a characteristic quantity model to provide a substitute air mass flow value based on other quantities, such as pressure and rotational speed, when the measured value is unreliable, ensuring accurate control of the engine by switching to a modeled value during unfavorable operating states and adapting the model accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an air mass flow sensor is used to measure air mass flow in a supercharged internal combustion engine, then air charge detection is enabled, but measurement accuracy deteriorates during high boost pressure and low air mass flow conditions
Solution Approach 1:
A substitute value calculation method is introduced as an intermediary solution when the air mass flow sensor becomes unreliable. The control unit calculates a substitute air mass flow value based on other measurable parameters (throttle valve position, pressures, temperatures) when compressor pumping is detected, thereby maintaining measurement accuracy without requiring sensor modification.
Solution Approach 2:
The system changes from using direct sensor measurements to using calculated substitute values based on different parameters (throttle position, pressure differential, temperature) when operating conditions become unfavorable. This parameter substitution resolves the measurement accuracy issue during high boost pressure and low air mass flow conditions.
2Productivity
If the air mass flow sensor operates during rapid load changes, then continuous air mass flow data is provided, but measurement reliability deteriorates due to compressor pumping
Solution Approach 1:
The control unit continuously monitors operating parameters (pressures, temperatures, throttle position) to detect compressor pumping conditions. When compressor pumping is detected, the system switches to using substitute value calculations, providing feedback-based adaptation that maintains reliability while preserving continuous data provision.
Solution Approach 2:
The system dynamically switches between using sensor measurements and calculated substitute values based on real-time operating conditions. This dynamic adaptation ensures continuous air mass flow data provision while maintaining reliability by selecting the appropriate data source based on current engine state.
3Measurement precision
If a substitute value model is used for air mass flow during unfavorable operating states, then measurement accuracy is maintained, but device complexity increases
Solution Approach 1:
Instead of using a complex alternative measurement system, the invention creates a computational model (copy) of the air mass flow calculation based on readily available sensor data from other parts of the system. This substitute value model maintains measurement precision while avoiding additional hardware complexity by utilizing existing sensors and computational algorithms.
Data Source
AI summary
A method for providing a characteristic quantity for a state of an air system of a supercharged internal combustion engine includes: detecting a characteristic quantity measured value as characteristic quantity information with the aid of a sensor; providing a characteristic quantity model, using which a characteristic quantity model value is computed on the basis of one or more quantities different from the characteristic quantity measured value; and providing the characteristic quantity either based on the characteristic quantity measured value or on the characteristic quantity model value computed by the characteristic quantity model, as a function of a state of the air system.