Air Mass Sensor Pulsation Correction via Turbocharger Ratios
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Solution Overview
Problem
Conventional pulsation correction methods for air mass sensors in internal combustion engines are inaccurate and complex, requiring recalibration over the engine's lifespan and involving multiple characteristic diagrams for different operating states, making them inefficient and cumbersome.
Innovation Solution
A method using a first correction factor based on the compression ratio of the exhaust gas turbocharger and a second factor based on the expansion ratio of the turbine, eliminating the need for actuator position corrections and allowing a single calibration, which remains effective across all engine operating states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pulsation correction methods using multiple characteristic diagrams and actuator positions are used, then measurement precision is improved for specific operating states, but device complexity increases and recalibration is required over engine lifespan
Solution Approach 1:
The patent uses a single universal correction factor that works across all engine operating states (different loads, speeds, and temperatures) rather than requiring separate characteristic diagrams for each state. This universal approach eliminates the complexity of storing and processing multiple correction maps while maintaining measurement accuracy throughout the engine's service life.
Solution Approach 2:
The patent changes the correction parameter from complex multi-dimensional characteristic diagrams (requiring engine speed, load, temperature, and actuator positions) to a simple single-parameter correction factor based on the ratio of instantaneous to mean air mass flow. This parameter transformation simplifies the correction system while preserving accuracy.
2Measurement precision
If multiple characteristic diagrams and correction factors are used for different operating states, then measurement precision is improved, but ease of operation deteriorates due to required recalibration
Solution Approach 1:
The single correction factor serves all operating states universally, eliminating the need for recalibration procedures that would otherwise be required when engine characteristics change over time or when switching between different operating modes. The system remains accurate throughout the engine's lifespan without maintenance intervention.
Solution Approach 2:
The correction system automatically adapts to different operating conditions through the ratio-based calculation method, which inherently compensates for changes in engine characteristics without requiring external recalibration or adjustment by the operator. The system self-corrects for varying operating states.
3Measurement precision
If conventional correction methods with multiple characteristic diagrams are used, then measurement precision is improved for transient states, but productivity decreases due to complex calculations
Solution Approach 1:
The patent transforms the correction calculation from complex multi-parameter interpolation across multiple characteristic diagrams to a simple ratio calculation between instantaneous and mean air mass flow values. This parameter simplification dramatically reduces computational burden while maintaining accuracy for both steady-state and transient operating conditions.
Solution Approach 2:
The patent extracts the essential correction need from the complex multi-diagram system and represents it through a single dominant factor (the ratio of instantaneous to mean flow). This extraction eliminates unnecessary computational complexity while preserving the core correction function.
Data Source
Figure 1A~1B
Figure 2
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AI summary
The invention relates to a method and a device for pulsation correction of an output signal of an air mass sensor for measuring the air mass of the combustion air of a turbocharged internal combustion engine. The method is characterized in that a first correction factor (10) and a second correction factor (18) are used to correct the output signal of the air mass sensor for pulsation effects. The first correction factor (10) is determined as a function of an output signal of the air mass sensor (1) and a compression ratio (8) of a compressor of an exhaust gas turbocharger, and the second correction factor (18) is determined as a function of a calculated exhaust gas mass flow (14) and an expansion ratio (16) of a turbine of an exhaust gas turbocharger.