Intake Passage Structure for Engine Water Hammer Prevention
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Solution Overview
Problem
The existing air intake passage structures for engines face challenges in preventing the reverse flow of condensed water, which can lead to the water hammer phenomenon, especially when the intercooler is positioned below the surge tank, causing durability issues and requiring non-compact engine layouts or inefficient communication pipes.
Innovation Solution
A reverse flow prevention structure is integrated into the air intake passage, specifically formed around the introduction port of the surge tank, using wall portions that rise from the bottom surface to catch condensed water before it reaches the intercooler, allowing for vertical alignment of the surge tank and intercooler while preventing reverse flow and maintaining a compact engine design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the intercooler is arranged below the surge tank to achieve compact layout, then the engine size is reduced, but condensed water accumulates in the intercooler and causes water hammer phenomenon
Solution Approach 1:
The patent introduces a vertical dimension to the air intake passage by forming a stepped structure with a first passage section at a higher level and a second passage section at a lower level. This vertical arrangement allows condensed water to drain downward to the second passage section while maintaining the compact intercooler placement below the surge tank, thus resolving the contradiction between compact engine size and prevention of water hammer phenomenon.
2Reliability
If the surge tank and intercooler are aligned horizontally to prevent reverse flow of condensed water, then water hammer is avoided, but the engine layout becomes non-compact and air intake passage arrangement is interfered
Solution Approach 1:
Instead of horizontal alignment, the patent uses vertical stacking with the surge tank positioned above the intercooler. The air intake passage is designed with stepped sections at different vertical levels, allowing condensed water to naturally drain downward to the lower second passage section. This vertical arrangement maintains compact engine layout while effectively preventing water hammer through gravity-driven drainage.
3Reliability
If a communication pipe is added to drain condensed water from the intercooler, then water hammer is prevented, but the device complexity increases
Solution Approach 1:
The patent merges the condensed water drainage function directly into the air intake passage structure by forming the passage with stepped sections at different levels. The lower second passage section serves dual purposes: as part of the air intake path and as a condensed water collection/drainage zone. This integration eliminates the need for separate communication pipes or drainage systems, reducing device complexity while maintaining effective water hammer prevention.
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
This configuration effectively suppresses the water hammer phenomenon by capturing condensed water and ensuring it does not enter the combustion chamber, while maintaining a compact engine layout without increasing intake air resistance.
Implementation Method 1
the condensed water that flows down by gravity is possibly accumulated in a bottom portion of the intercooler
Data Source
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AI summary
An air intake passage (30) has a third passage (37) that connects an intercooler (36) and a bottom portion of a surge tank (38) such that the intercooler (36) is positioned below the surge tank (38). A pair of wall portions (71, 72) configured to catch moisture is formed in a section from an upstream end portion of the third passage (37) to a connected portion between said third passage (37) and the surge tank (38).