LNG Engine Controller Startup Parameter Adaptation
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Solution Overview
Problem
Existing methods for internal combustion engines operated with liquefied natural gas require identification of current gas composition upon startup, which is time-consuming and inefficient, as they rely on pre-stored parameters that may not reflect the actual composition changes due to storage duration, temperature, and pressure variations.
Innovation Solution
Sensing the duration of engine stoppage, ambient and tank temperatures, and pressure during shutdown, and using these data to update combustion parameters through characteristics diagrams, ensuring immediate adaptation upon startup for optimized combustion and reduced emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If pre-stored combustion parameters are used upon startup, then the engine can start immediately, but the parameters may not reflect actual gas composition changes due to storage duration, temperature, and pressure variations
Solution Approach 1:
The system performs preliminary calculations of gas composition changes based on storage duration, temperature, and pressure before the engine actually starts. By pre-computing the expected composition changes using characteristics diagrams, the system can immediately apply corrected combustion parameters upon startup without requiring actual measurement time, thus resolving the contradiction between fast startup and accurate composition reflection.
2Measurement precision
If gas composition is identified upon startup, then current gas composition is accurately reflected, but the process is time-consuming and inefficient
Solution Approach 1:
Instead of performing actual gas composition identification measurements at startup, the system pre-calculates the expected composition changes based on stored operational data (storage duration, temperature, pressure) and uses characteristics diagrams to determine corrected combustion parameters in advance. This preliminary action eliminates the time-consuming measurement process while maintaining accurate composition reflection.
Solution Approach 2:
The system replaces physical/chemical measurement methods (using lambda probes and actual gas analysis) with computational methods based on thermodynamic characteristics diagrams and mathematical models. This substitution allows the system to determine gas composition changes through calculations rather than physical measurement, significantly improving startup efficiency while maintaining accuracy.
3Reliability
If combustion parameters are adapted to current gas composition, then optimized combustion and reduced emissions are achieved, but the adaptation process takes time
Solution Approach 1:
The system pre-determines the necessary parameter adaptations by calculating expected gas composition changes based on storage conditions before the engine starts. By using characteristics diagrams that pre-map the relationship between storage parameters and composition changes, the system can immediately apply the correct combustion parameters upon startup, eliminating the time delay that would otherwise be required for real-time adaptation.
Data Source
AI summary
A method is provided for setting combustion parameters of an internal combustion engine operated with liquefied natural gas, the combustion parameters being sensed during operation of the internal combustion engine and being stored upon shutoff of the internal combustion engine. Also provided is a controller for carrying out the method. Provision is made that during a stoppage of the internal combustion engine, the duration of the stoppage, the ambient temperature and/or tank temperature, and the pressure in a liquefied gas tank are sensed; the influence thereof on a required adaptation of the combustion parameters that are to be set is identified from a characteristics diagram; and from the stored combustion parameters and the adaptation, initial combustion parameters are identified and are used upon startup of the internal combustion engine in order to control it.