Biofuel Content Determination via NOx Sensor Correlation
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Solution Overview
Problem
Existing systems fail to accurately determine biofuel content in internal combustion engines, especially when operating under non-stoichiometric conditions, leading to errors in air-fuel ratios and engine performance metrics like NOx emissions and fuel efficiency.
Innovation Solution
A control system comprising a controller with modules for interpreting oxygen and NOx sensor data, correlating intake and exhaust oxygen values, and adjusting fueling parameters to determine biofuel content, which includes an operation conditions module, O2 fuel determination module, and biofuel reporting module, enabling precise biofuel content calculation and engine operation optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional air-fuel ratio sensing systems are used, then system simplicity is maintained, but measurement precision of biofuel content deteriorates under non-stoichiometric conditions
Solution Approach 1:
The control system is segmented into distinct functional modules: an air-fuel ratio sensing module using NOx sensors, an oxygen concentration sensing module, a biofuel content determination module, and a fuel injection control module. This segmentation allows each module to perform its specific function optimally while working together to achieve accurate biofuel content determination under non-stoichiometric conditions.
Solution Approach 2:
The system uses NOx sensor output signals as an intermediary parameter to indirectly determine oxygen concentration and biofuel content. Rather than directly measuring oxygen concentration which is difficult under non-stoichiometric conditions, the system uses the NOx sensor output as a mediator that correlates with oxygen concentration, enabling accurate biofuel content determination through the relationship between NOx emissions and fuel composition.
2Productivity
If real-time biofuel content determination is implemented, then engine performance optimization is improved, but calculation complexity increases
Solution Approach 1:
The system pre-establishes the correlation relationship between NOx sensor output signals and oxygen concentration, and between oxygen concentration and biofuel content. By pre-defining these relationships, the system avoids complex real-time calculations and instead uses pre-computed correlation data to quickly determine biofuel content and optimize engine performance in real-time.
Solution Approach 2:
The system implements a feedback loop where the determined biofuel content is continuously used to adjust fuel injection parameters, and the NOx sensor continuously monitors exhaust conditions to verify and refine the biofuel content determination. This feedback mechanism enables real-time optimization while using iterative refinement rather than complex one-time calculations.
3Measurement precision
If multiple sensor types are used to determine biofuel content, then measurement precision improves, but device complexity increases
Solution Approach 1:
The NOx sensor is designed to serve multiple functions: it primarily detects NOx emissions for emission control, but its output signal is also used to determine oxygen concentration and subsequently biofuel content. This multi-functionality allows the system to achieve accurate biofuel content determination without adding dedicated oxygen sensors, thereby improving measurement precision while limiting the increase in device complexity.
Data Source
AI summary
A system includes an internal combustion engine having an air intake, a fuel inlet, and exhaust outlet. The system further includes a NOx sensor operably coupled to the exhaust outlet and structured to provide an exhaust O2 value, and a controller structured to functionally execute operations for determining a tank biofuel value. The controller includes an operation conditions module that interprets an intake O2 value, the exhaust O2 value, and a biofuel O2 correlation, an O2 fuel determination module that determines an O2 biofuel value in response to the intake O2 value, the exhaust O2 value, and the biofuel O2 correlation, and a fuel composition module that determines a tank biofuel value in response to the O2 biofuel value. The controller further includes a biofuel reporting module that provides the tank biofuel value.