Ion Current Sensor for In-Cylinder Soot Measurement
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Solution Overview
Problem
Current technologies for soot measurement in commercial engines are either expensive, limited to research settings, or unable to accurately predict soot production in real-time, lacking an effective, cost-efficient method for in-cylinder measurement.
Innovation Solution
An ion current sensor system is integrated inside the engine cylinder to measure soot, engine load, and fuel consumption on a cyclic basis, providing a feedback signal for engine control, enabling accurate and fast prediction of soot formation and fuel consumption, compliant with stringent emissions rules without engine modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser techniques are used for soot measurement, then measurement precision is improved, but device complexity and cost increase making it unsuitable for commercial engines
Solution Approach 1:
The patent replaces complex optical laser measurement systems with a simple ion current sensor that uses electrical field principles. The ion sensor measures soot formation through ion current characteristics without requiring optical access or complex instrumentation, making the system suitable for commercial engine applications while maintaining measurement capability.
Solution Approach 2:
The ion current sensor is a cost-effective, simple device compared to expensive laser instrumentation. It provides adequate measurement precision for commercial applications at a fraction of the cost of research-grade optical systems, enabling widespread deployment in production engines.
2Measurement precision
If sampling techniques are used for soot measurement, then measurement precision is improved, but device complexity and cost increase requiring expensive instrumentation
Solution Approach 1:
The patent replaces mechanical sampling systems with electrical field-based ion current measurement. Instead of physically sampling exhaust gases with complex tubing and filters, the ion sensor directly measures ion current in the combustion chamber, eliminating the need for expensive sampling instrumentation while maintaining measurement precision.
3Device complexity
If exhaust pipe sensors are used for soot measurement, then device complexity is reduced, but measurement precision and response speed worsen due to slow access to soot data
Solution Approach 1:
The ion sensor measures soot formation in real-time within the combustion chamber before exhaust gases leave the cylinder. This preliminary measurement allows the system to detect and respond to soot formation events as they occur, providing accurate soot prediction data that exhaust pipe sensors cannot capture due to their delayed position downstream.
Solution Approach 2:
The ion current signal provides immediate feedback on combustion conditions and soot formation for each cylinder cycle. This real-time feedback enables the control system to adjust injection parameters to optimize combustion and reduce soot formation, a capability that exhaust pipe sensors lack due to their slow response time.
4Device complexity
If exhaust pipe sensors are used for soot measurement, then device complexity is reduced, but measurement precision worsens due to inability to predict soot per cylinder
Solution Approach 1:
The ion sensor system provides segmented measurement data for each individual cylinder, allowing the system to identify which specific cylinders are producing excessive soot. This per-cylinder resolution enables targeted control strategies, unlike exhaust pipe sensors that only provide aggregated exhaust stream measurements.
5Ease of operation
If speed density method is used for load measurement, then ease of operation is improved, but measurement precision worsens due to sensitivity to temperature changes
Solution Approach 1:
The ion current signal provides direct feedback on in-cylinder combustion conditions and load. This measurement is less sensitive to intake temperature variations because it directly senses ion current generated during combustion rather than relying on air flow calculations that are temperature-dependent, improving load measurement precision.
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
The system offers a cost-effective, real-time measurement of soot, load, and fuel consumption, allowing for precise engine control, reducing soot production, and meeting EPA emissions standards with a compact, efficient design suitable for production models.
Implementation Method 1
utilizes the characteristics of an ion current sensor signal for onboard measurement of in-cylinder variables such as soot
Data Source
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AI summary
A system and method is provided for the use of the ion current signal characteristics for onboard cycle-by-cycle, cylinder-by-cylinder measurement, for example soot measurement, load measurement such as indicated or brake mean effective pressure, or fuel consumption measurement in an internal combustion engine. The system may acquire an ion current signal, measures one or more of soot, load, fuel consumption and may control the engine operating parameters accordingly.