Estimating NOx Emissions in Heat Engine Alternative Modes
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Solution Overview
Problem
Current systems cannot accurately and quickly estimate nitrogen oxide emissions at the outlet of a thermal engine for alternative operating modes, as not all parameters accessible during the current mode are available for alternative settings, making it difficult to manage performance and regulatory constraints.
Innovation Solution
The method employs transfer functions based on common engine control parameters like engine speed, torque, temperature, and air temperature to estimate nitrogen oxide emissions for alternative modes, using a simplified approach by reducing the number of parameters considered and utilizing maps from engine bench testing to correct pollutant ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all parameters for pollutant estimation are made accessible for alternative modes, then measurement precision of nitrogen oxide emissions would be improved, but device complexity and cost would increase due to requiring new hardware
Solution Approach 1:
The patent creates a virtual model (copy) of the combustion chamber that simulates nitrogen oxide formation based on available engine parameters. Instead of physically measuring NOx in alternative modes, the system uses a computational model that replicates the combustion process and predicts emissions, thereby achieving accurate estimation without additional measurement hardware.
Solution Approach 2:
The patent replaces physical measurement systems with a computational estimation system. The control computer uses software algorithms to calculate nitrogen oxide emissions based on engine parameters, substituting mechanical/sensor-based measurement with mathematical modeling and data processing.
2Manufacturing precision
If comprehensive parameters are used for pollutant estimation in alternative modes, then manufacturing precision of emissions control would be improved, but ease of manufacture would worsen due to system complexity
Solution Approach 1:
The patent makes the control computer perform multiple functions: it not only controls the diesel injection system but also estimates nitrogen oxide emissions for both current and alternative combustion modes. This multi-functionality allows the existing control unit to provide emissions predictions without requiring separate dedicated hardware, simplifying manufacturing.
3Reliability
If transient effects are taken into account for alternative modes, then reliability of emissions estimation would be improved, but loss of time for calculation would increase
Solution Approach 1:
The patent pre-calculates and stores transfer functions that relate nitrogen oxide emissions to engine parameters for various operating conditions. By preparing these relationships in advance, the system can quickly estimate emissions for alternative modes during operation without performing complex real-time calculations, thus maintaining both accuracy and speed.
Data Source
Figure 1~2
AI summary
The invention relates to a method for controlling the emission of a pollutant present in the exhaust gases of a heat engine, in which several operating modes are stored, including at least one normal mode and at least one alternating mode. A quantity of pollutant (NOx normal) according to said at least one normal mode is measured or estimated. A ratio (ratio b) of pollutant quantities between said at least one normal mode and said at least one alternating mode is estimated as a function of a group of parameters accessible during said at least one normal mode. A quantity of pollutant (NOx alternating) according to said at least one alternating mode is estimated as a function of the quantity of pollutant (NOx normal) according to said at least one normal mode and said ratio (ratio b) of pollutant quantities.