Intake Port Convex Portion Prevents Fuel-Air Backflow
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Solution Overview
Problem
Existing intake structures for internal combustion engines fail to prevent backflow of the fuel-air mixture into the intake port, especially at high expansion ratios, leading to reduced charging efficiency and potential variations in the position of formed components due to machining and casting inaccuracies.
Innovation Solution
An intake structure featuring a convex portion with an upstream guide surface and a downstream guide surface within the intake port, where the downstream guide surface directs the fuel-air mixture from the outer circumferential wall to the central wall, preventing backflow and enhancing tumble flow formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a strong tumble flow is formed in the cylinder chamber, then combustion efficiency is improved, but fuel-air mixture backflow to the intake port occurs
Solution Approach 1:
The intake port is divided into multiple regions by introducing a convex portion with upstream and downstream guide surfaces. This segmentation creates distinct flow paths: a first flow path for tumble flow generation and a second flow path for preventing backflow, allowing the system to simultaneously achieve strong tumble flow and prevent fuel-air mixture backflow to the intake port
Solution Approach 2:
The convex portion with guide surfaces acts as an intermediary structure between the intake port and cylinder chamber. The upstream guide surface generates tumble flow while the downstream guide surface intercepts and redirects the fuel-air mixture, preventing it from returning to the intake port. This intermediary structure resolves the contradiction by mediating between the need for strong tumble flow and the need to prevent backflow
2Power
If stepped part is formed by machine processing, then tumble flow generation is improved, but position variation occurs due to processing accuracy
Solution Approach 1:
The convex portion is formed as an integral part of the intake port structure through molding, allowing it to self-form without separate machining operations. This self-service approach eliminates the need for post-molding machining, thereby preventing position variations caused by machining accuracy limitations while maintaining the tumble flow generation function
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
Effectively prevents backflow of the fuel-air mixture into the intake port, thereby improving charging efficiency and stabilizing the formation of a strong tumble flow, while simplifying production and reducing turbulence effects.
Implementation Method 1
the downstream guide surface guides the fuel-air mixture, which is guided by the tumble flow from the cylinder chamber to the outer circumferential wall part about to return to the intake port, from the outer circumferential wall part to the central wall part
Implementation Method 2
a tumble flow swirling along an axis direction of a sylinder chamber is formed by intake air
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
In an intake structure of an internal combustion engine (10), on an intake upstream side from a valve seat (32) of an intake port (22), a convex portion (36) is provided which protrudes to an inside of the intake port (22) in a place near an outer circumferential portion of a cylinder chamber (12) when viewed from an upper side of the cylinder chamber (12). The convex portion (36) includes an upstream guide surface (3602) extending from an apex (3610) of the convex portion (36) to the intake upstream side, and a downstream guide surface (3604) extending from the apex (3610) to an intake downstream side and including a curved surface recessed inside the convex portion (36) at a middle portion thereof.