Gas Engine Valve System with Nested Linear and Rotating Control
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Solution Overview
Problem
Traditional valve systems in gas engines require large volumes and complex double-pipe guides for gas delivery, leading to inefficiencies in gas control and increased production costs, especially in lean burn engines where NOx formation and thermal loads are concerns, and in marine applications where double-walled pipes are mandated.
Innovation Solution
A valve system with a centrally placed linearly moving admission valve and a surrounding rotating control valve, where the control valve is equipped with a drive mechanism, such as a cogged rod or worm gear, to reduce the volume between the valves by approximately 90%, eliminating the need for double-pipe guides and enhancing gas control precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional valve systems with separate control valve and admission valve are used, then gas supply control is provided, but the volume between valves is large leading to imprecise gas control
Solution Approach 1:
The control valve and admission valve are merged into a single integrated valve unit. The control valve is positioned inside the valve housing with its outlet directly connected to the admission valve inlet, eliminating the intermediate gas manifold and reducing the volume between valves to minimal levels, thereby achieving precise gas control.
Solution Approach 2:
The control valve is nested within the valve housing structure, with the admission valve positioned around it. The control valve outlet is directly connected to the admission valve inlet through a minimal volume passage, creating a compact nested arrangement that minimizes the gas volume between control and admission functions.
2Reliability
If double-pipe guides are used for gas delivery in marine applications, then gas leak detection is enabled, but construction complexity and production costs increase
Solution Approach 1:
The double-pipe guide structure is extracted and replaced by positioning the entire integrated valve unit (control valve and admission valve) directly inside the valve housing. This eliminates the need for complex double-pipe guides running along the engine while maintaining gas delivery and leak detection capabilities through the compact internal arrangement.
Solution Approach 2:
The valve components are merged and positioned inside the valve housing, integrating the gas delivery function with the housing structure itself. This consolidation eliminates the separate double-pipe guide system while maintaining reliability through the sealed internal configuration.
3Reliability
If pre-combustion chamber is used for ignition reinforcement, then steady ignition is achieved, but thermal load and NOx formation increase
Solution Approach 1:
The control valve precisely regulates the amount of fuel gas supplied to the pre-combustion chamber by adjusting the valve opening degree based on engine load. This parameter control optimizes the rich charge mixture quantity, enabling stable ignition while minimizing excess fuel that would otherwise increase thermal load and NOx formation.
Data Source
Figure 1~2
AI summary
A valve system is described for a gas engine (20) comprising a number of valves (36, 44) that are arranged to regulate the amount and supply of gas into an inlet manifold (16) in the engine (20). The system comprises a valve housing (30) equipped with a centrally placed and linearly moving control valve (36) and a surrounding admission valve (44), where the admission valve (44) is arranged to rotate to regulate the amount of gas that is let into the valve housing (30).