Separate Elastic Suction Tubes for Stratified Scavenging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In stratified scavenging engines, the integration of mixture and air passages in a single suction tube leads to deformation of the partition, causing misalignment and mixed flow of fuel and air, which disrupts the stratified scavenging operation and alters the air passage cross-sectional profile, affecting flow rates and engine performance.
Innovation Solution
A suction tube unit with separate elastic material tubes for mixture and air, featuring complementary wall portions with a clearance space to prevent deformation-induced misalignment and mixed flow, and an adapter with a recess to enhance sealing and maintain the air passage profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single suction tube with an integrated partition is used to supply both mixture and air passages, then the engine structure becomes compact, but the partition deforms under negative pressure and fuel exposure causing misalignment and mixed flow
Solution Approach 1:
The single suction tube with partition is divided into two separate suction tubes (one for mixture, one for air). Each tube is made of elastic material and maintains its own structural integrity independently, preventing the partition deformation and misalignment issues that occur in integrated designs.
Solution Approach 2:
A common wall portion acts as an intermediary structure between the two separate suction tubes. This common wall provides structural support and maintains the clearance space relationship between the tubes while allowing both tubes to be made of elastic material for vibration damping.
2Object-affected harmful factors
If the suction tube is made of elastic material to prevent vibration transmission, then vibration damping is improved, but the tube deforms under negative pressure causing passage profile changes
Solution Approach 1:
The harmful effect of elastic deformation under negative pressure is extracted and isolated to the mixture suction tube only. The air suction tube maintains its rigid structure to preserve the passage profile, while the mixture tube's deformation is contained and does not affect the air passage.
Solution Approach 2:
Different parts of the suction tube unit have different material properties: the mixture suction tube is made of elastic material for vibration damping, while the air suction tube maintains a rigid structure to preserve passage profile. The common wall portion provides localized structural support.
3Adaptability or versatility
If the partition deforms under negative pressure, then the suction tube can accommodate pressure changes, but the passage for air cross-sectional profile changes affecting flow rate
Solution Approach 1:
The pressure adaptation function is segmented and assigned only to the mixture suction tube, which deforms elastically under negative pressure. The air suction tube remains structurally stable to maintain its passage profile and ensure consistent air flow rate, while both tubes are connected through the common wall structure.
Data Source
AI summary
A suction tube unit connected between a cylinder block and a carburetor in a stratified scavenging engine has a suction tube for mixture made of an elastic material; and a suction tube for stratified scavenging air made of an elastic material. The suction tube for mixture and the suction tube for air have, at respective inlet ends connected to the carburetor, respective wall portions which face each other and have complementary shapes. A clearance space is provided between the wall portions of the suction tube for mixture and the suction tube for air.