Suction tube unit of stratified scavenging engine

Patent metadata

Field	Value
Publication number	US-9988970-B2
Application number	US-201514934719-A
Country	US
Kind code	B2
Filing date	Nov 6, 2015
Priority date	Nov 28, 2014
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

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.

First claim

What is claimed:

1. A suction tube unit for a carburetor having one bore including a mixture-flow passage and a scavenging-air-flow passage, the passages being defined on opposite sides of a full-opened butterfly-type valve, the suction tube unit comprising:
a suction tube for mixture, the suction tube for mixture being made of an elastic material;
a suction tube for stratified scavenging air, the suction tube for air being made of an elastic material, and
an adapter disposed between the carburetor and the suction tube for mixture and between the carburetor and the suction tube for air,
wherein the suction tube for mixture and the suction tube for air have, at respective inlet ends connected to the adapter, respective wall portions which face each other and have complementary shapes,
wherein a clearance space is provided between the wall portions of the suction tube for mixture and the suction tube for air,
wherein the adapter has one bore, and
wherein a single partition aligning with the wall portions of the suction tube for mixture and the suction tube for air is provided in the one bore, and the partition has a recess fitted to the wall portions of the suction tube for mixture and the suction tube for air.

2. The suction tube unit according to claim 1 , wherein the adapter has a recess which receives the inlet end of the suction tube for mixture and the inlet end of the suction tube for air.

3. The suction tube unit according to claim 1 , wherein the wall portion of the suction tube for mixture has a reinforcing rib.

4. The suction tube unit according to claim 1 , wherein the suction tube for mixture and the suction tube for air are made of different materials.

5. The suction tube unit according to claim 1 , wherein the wall portion of the suction tube for mixture and the wall portion of the suction tube for air are planar.

6. A stratified scavenging engine comprising:
a suction tube unit, comprising:
a suction tube for mixture, the suction tube for mixture being made of an elastic material;
a suction tube for stratified scavenging air, the suction tube for air being made of an elastic material,
a carburetor having one bore including a mixture-flow passage and a scavenging-air-flow passage, the passages being defined on opposite sides of a full-opened butterfly-type valve, and
an adapter disposed between the carburetor and the suction tube for mixture and between the carburetor and the suction tube for air,
wherein the suction tube for mixture and the suction tube for air have, at respective inlet ends connected to the adapter, respective wall portions which face each other and have complementary shapes,
wherein a clearance space is provided between the wall portions of the suction tube for mixture and the suction tube for air;
wherein the adapter has one bore; and
wherein a single partition aligning with the wall portions of the suction tube for mixture and the suction tube for air is provided in the one bore, and the partition has a recess fitted to the wall portions of the suction tube for mixture and the suction tube for air.

7. The stratified scavenging engine according to claim 6 , wherein the carburetor butterfly-type valve comprises a choke valve and a throttle valve.

Assignees

• Yamabiko Corp

Inventors

• Ohsawa Hisato
• Yamazaki Takahiro
• Tsunoda Hidekazu

Classifications

• F02M35/10314

  Materials for intake systems (for sound damping F02M35/12; for air cleaners F02M35/02) · CPC title

• F02M35/10085

  having a connecting piece, e.g. a flange, between the engine and the air intake being foreseen with a throttle valve, fuel injector, mixture ducts or the like · CPC title

• F02B25/22

  by forming air cushion between charge and combustion residues · CPC title

• F02M13/021

  Particular constructional measures of the intake conduits between carburettors and cylinder · CPC title

• F02M35/1019

  Two-stroke engines; Reverse-flow scavenged or cross scavenged engines · CPC title