Gasket Integrated Leaf Valve for Two-Stroke Engine Scavenging
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Solution Overview
Problem
Crankcase compression type stratified scavenging two-stroke cycle engines face challenges in reducing manufacturing costs and complexity due to the need for multiple parts and valves to manage air flow direction effectively.
Innovation Solution
A compact check valve design integrated into a gasket with a leaf valve, which allows air to flow only in one direction, reducing the number of parts and manufacturing costs while maintaining engine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate check valve assembly is used to control air flow direction, then air flow control reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The check valve function is merged with the gasket by integrating a flexible valve element directly into the gasket structure. The gasket itself serves dual purposes: sealing the air supply chamber and providing the check valve function to control air flow direction. This eliminates the need for a separate check valve assembly, reducing part count while maintaining air flow control reliability.
Solution Approach 2:
The gasket is designed to perform multiple functions simultaneously: it seals the air supply chamber, provides the check valve function for unidirectional air flow control, and interfaces between the carburetor and engine components. This multi-functional design reduces overall device complexity while ensuring reliable air flow management.
2Manufacturing precision
If multiple separate components are used for check valve function, then manufacturing precision can be maintained, but manufacturing cost increases
Solution Approach 1:
The check valve functionality is combined with the gasket into a single integrated component. This reduces the total number of parts that need to be manufactured and assembled, lowering manufacturing costs. The integrated design maintains precision through careful formulation of the flexible material and precise molding of the valve element within the gasket structure.
Solution Approach 2:
The check valve function is achieved through changes in the physical parameters of the gasket material, specifically using a flexible material that can deform under pressure differential. This approach replaces traditional mechanical valve components with a material-based solution, simplifying manufacturing while maintaining functional precision.
3Ease of manufacture
If a simple gasket without integrated check valve is used, then manufacturing cost decreases, but air flow control capability is lost
Solution Approach 1:
The check valve function is merged into the gasket structure, allowing the component to maintain simplicity in assembly and manufacturing while simultaneously providing reliable air flow direction control. The flexible valve element within the gasket automatically responds to pressure differentials to ensure unidirectional air flow.
Solution Approach 2:
The integrated check valve in the gasket operates automatically based on pressure differential without requiring external control mechanisms. The flexible material naturally deforms to allow air flow in the correct direction and blocks reverse flow, providing self-regulating air flow control that maintains reliability while keeping the design simple.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables efficient one-way air flow, preventing reverse flow and reducing production costs by simplifying the engine design without compromising performance.
Implementation Method 1
When negative pressure is produced in the air supply chamber 1b, the leaf valve 11 bends as shown by chain line in FIG.4 pulled by pressure difference between the air flow passage 7 and the air supply chamber 1b
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3A~3B
AI summary
A stratified scavenging two-stroke cycle engine with the check valve (23b) for introducing scavenging air simplified in construction is provided. The gasket (23) between the flange part forming an air supply chamber (21c) and a mixture passage (21d) at a side of the cylinder and the passage connecting member (22) having an air flow passage (7) and a mixture flow passage (6) is composed to have an integral leaf (23b) valve for allowing air in the air flow passage (7) in the passage connecting member (22) to flow only toward the air supply chamber (21c) which is connected to the scavenging passages of the engine so that the gasket (23) has a function as a seal member and that as a check valve.