Particulate Matter Sensor Signal Processing for Engine Emissions
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Solution Overview
Problem
Existing technologies face challenges in processing and analyzing real-time particle sensor data from engine exhaust events to effectively monitor and control particulate emissions, particularly in identifying variations in engine operation and emissions across cylinders and cycles.
Innovation Solution
A processor-based system that combines time-windowed and frequency domain analysis of exhaust particulates using particulate matter sensors and charge amplifiers, along with signal processing electronics, to create profiles of cylinder behavior and detect harmonic frequencies indicative of engine performance, allowing for real-time data conversion and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If real-time particle sensor data from engine exhaust is processed using time-windowed and frequency domain analysis, then the ability to identify variations in engine operation and emissions across cylinders and cycles is improved, but the device complexity and computational requirements increase
Solution Approach 1:
The patent segments the continuous exhaust stream into discrete time windows corresponding to individual cylinder exhaust events. By dividing the signal processing into time-windowed segments and applying frequency domain analysis to each segment, the system can identify variations across cylinders and cycles with improved precision while managing computational complexity through structured segmentation of the data processing task.
2Loss of information
If signal processing electronics and charge amplifiers are used to convert and analyze particle sensor signals, then the ability to detect harmonic frequencies indicative of engine performance is improved, but the device complexity increases
Solution Approach 1:
The patent introduces charge amplifiers and signal processing electronics as intermediary devices between the particle sensor and the analysis system. These intermediaries convert the raw particle sensor signals into processed signals that preserve information about engine performance and harmonic frequencies, enabling detection of subtle performance variations without requiring direct complex processing of the original sensor output.
3Reliability
If time-domain and frequency-domain analysis are combined to create profiles of cylinder behavior, then the ability to compare cylinders and control emissions is improved, but the processing time and computational load increase
Solution Approach 1:
The patent applies time-windowing as a preliminary action that organizes the continuous signal into discrete cylindrical events before frequency domain analysis. This preliminary structuring of data into manageable time windows corresponding to individual cylinder cycles enables more efficient subsequent processing and facilitates real-time comparison across cylinders while maintaining reliable emission control through systematic analysis of each windowed segment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the derivation of usable control signals for improved engine performance and reduced emissions by identifying instantaneous and time-averaged results, facilitating better engine operation and emission control.
Implementation Method 1
a conductive probe connected to a charge amplifier which records the concentration of particles as a function of time
Data Source
AI summary
A system having a particulate matter sensor in an exhaust stream of an engine upstream from a particulate filter and another such sensor downstream from the filter. There may also be an exhaust gas recirculation (EGR) control on the engine. The amount of particulate matter in or loading of the filter may be determined by the upstream filter. The working condition of the filter may be determined by the downstream sensor. The filter may have a heater and control for providing operational and particulate matter burn-off temperatures to the filter. A processor may be connected to the sensors, the EGR control and the filter heater control.