Gas Engine Intake Mixture Modeling for Transient Emissions Control
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Solution Overview
Problem
Existing gas-powered internal combustion engines, particularly spark-ignition gas engines, face challenges in transient operation and emissions control, especially in the low-load range, due to imprecise mixture formation and large volumes in the intake tract leading to fluctuations in pressure and temperature, resulting in high hydrocarbon emissions and poor efficiency.
Innovation Solution
A method and device that utilize a computational model to determine the mixture fraction at the gas mixer and adjust airflow and gas flow based on intake path modeling, considering large volumes and pressure changes, with a virtual mixture mass sensor to optimize mixture formation and emissions control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the intake tract volume is increased to improve charge storage capacity, then the engine can handle larger load variations, but pressure and temperature fluctuations increase leading to poor mixture formation
Solution Approach 1:
The patent segments the intake tract into multiple controlled zones with individual throttle valves, allowing independent control of charge flow to different cylinders. This segmentation enables precise mixture formation control while maintaining adequate charge storage capacity in each segment, resolving the contradiction between large volume and mixture quality.
2Adaptability or versatility
If the engine operates in transient load range with variable fuel qualities, then adaptability to different operating conditions is improved, but mixture formation precision deteriorates due to pressure and temperature fluctuations
Solution Approach 1:
The patent implements dynamic control of throttle valves in the intake tract, allowing real-time adjustment of charge flow parameters in response to transient load changes and variable fuel qualities. This dynamic adaptation maintains precise mixture formation across different operating conditions by actively compensating for pressure and temperature fluctuations.
3Device complexity
If the intake manifold is designed as a homogeneous pressure vessel to simplify control, then device complexity is reduced, but the inability to account for large volume effects leads to high emissions
Solution Approach 1:
The patent divides the intake manifold into multiple segments with individual throttle control, transforming the homogeneous pressure vessel concept into a distributed control system. This segmentation enables precise control of charge distribution to each cylinder, reducing hydrocarbon emissions from unburned fuel while maintaining manageable system complexity through modular architecture.
Data Source
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AI summary
Method for operating a gas internal combustion engine (100), having - a gas mixer (40), an intake section (30) and - an engine (10) with a number of cylinders, wherein in the method - a fuel mixture comprising a charging mixture is fed to the engine (10), and the engine (10) is operated in the gas mode with gas as the fuel in the charging mixture, wherein - by means of an input mixture portion, assigned to at least one earlier mixture state, of a gas/air mixture, an output mixture portion, assigned to a later mixture state, of the gas/air mixture is determined, and wherein the determination is carried out by means of an intake section model which serves as a basis of a computing model for the intake section (30). The invention provides that - the output mixture portion of the gas/air mixture is determined at an engine feed, - the input mixture portion of the output mixture portion is determined over a number of intermediate states of the mixture portion in a number of assigned volumes of the intake section (30), wherein - the intake mixture portion of a gas/air mixture is determined at the gas mixer (40), and an air stream and/or gas stream is set at the gas mixer (40) in accordance with the input mixture portion.