Stratified Scavenging Two-Stroke Internal Combustion Engine, Air Cleaner Of The Same, And Intake Method

Patent metadata

Field	Value
Publication number	US-2016376979-A1
Application number	US-201615189013-A
Country	US
Kind code	A1
Filing date	Jun 22, 2016
Priority date	Jun 24, 2015
Publication date	Dec 29, 2016
Grant date	—

Abstract

An amplitude of a pressure fluctuation in a vicinity of a main nozzle of a carburetor ( 32 ) is decreased. An air cleaner ( 30 ) has a first inlet ( 60 ) that feeds air to an intake system air channel, and a second inlet ( 62 ) that feeds air to an intake system air-fuel mixture channel. A channel formation member ( 70 ) is attached to the second inlet ( 62 ). A channel length (L 2 ) of an extension channel ( 72 ) formed by the channel formation member ( 70 ) is 110 mm or more.

First claim

What is claimed is:

1 . A stratified scavenging two-stroke internal combustion engine configured to feed a combustion chamber with first leading air and subsequently with air-fuel mixture from a crank chamber in a scavenging stroke of the engine, comprising:
an intake device having an air channel and an air-fuel mixture channel, the air channel feeding the leading air to an engine body, and the air-fuel mixture channel generating the air-fuel mixture and feeding the air-fuel mixture to the crank chamber of the engine body; and an opening portion provided in the intake device to make communication between the air channel and the air-fuel mixture channel, wherein one of the air channel and the air-fuel mixture channel is longer by 110 mm or more than the other of the air channel and the air-fuel mixture channel when viewed in an upstream side of the opening portion.

2 . The stratified scavenging two-stroke internal combustion engine of claim 1 , wherein said one of the air channel and the air-fuel mixture channel is longer by 120 mm or more than the other of the air channel and the air-fuel mixture channel when viewed in an upstream side of the opening portion.

3 . The stratified scavenging two-stroke internal combustion engine of claim 1 , wherein said one of the air channel and the air-fuel mixture channel is longer by a value not exceeding 254 mm than the other of the air channel and the air-fuel mixture channel when viewed in an upstream side of the opening portion.

4 . The stratified scavenging two-stroke internal combustion engine of claim 2 , wherein said one, of the air channel and the air-fuel mixture channel is longer by a value not exceeding 254 mm than the other of the air channel and the air-fuel mixture channel when viewed in an upstream side of the opening portion.

5 . The stratified scavenging two-stroke internal combustion engine of claim 1 ,
the stratified scavenging two-stroke internal combustion engine comprising a carburetor, wherein the carburetor has a main nozzle for feeding fuel to the air-fuel mixture channel, and the opening portion is located in a vicinity of the main nozzle.

6 . The stratified scavenging two-stroke internal combustion engine of claim 2 ,
the stratified scavenging two-stroke internal combustion engine comprising a carburetor, wherein the carburetor has a main nozzle for feeding fuel to the air-fuel mixture channel, and the opening portion is located in a vicinity of the main nozzle.

7 . The stratified scavenging two-stroke internal combustion engine of claim 3 ,
the stratified scavenging two-stroke internal combustion engine comprising a carburetor, wherein the carburetor has a main nozzle for feeding fuel to the air-fuel mixture channel, and the opening portion is located in a vicinity of the main nozzle.

8 . The stratified scavenging two-stroke internal combustion engine of claim 4 ,
the stratified scavenging two-stroke internal combustion engine comprising a carburetor, wherein the carburetor has a main nozzle for feeding fuel to the air-fuel mixture channel, and the opening portion is located in a vicinity of the main nozzle.

9 . An air cleaner for a stratified scavenging two-stroke internal combustion engine, the engine having
an engine body configured to feed a combustion chamber with first leading air and subsequently with air-fuel mixture from a crank chamber in a scavenging stroke of the engine, an air channel for feeding air for the leading air to the engine body, an air-fuel mixture channel for feeding the air-fuel mixture to a crank chamber of the engine body, a carburetor including a main nozzle for feeding fuel to the air-fuel mixture channel, and an opening portion making communication between the air channel and the air-fuel mixture channel, the air cleaner comprising: a cleaner element for filtering outside air; a first inlet for feeding purified air filtered through the cleaner element to the air channel; a second inlet for feeding the purified air filtered through the cleaner element to the air-fuel mixture channel; and a channel formation member attached to one of the first inlet and the second inlet to extend said one of the first inlet and the second inlet, wherein a channel length of an extension channel formed by the channel formation member is 110 mm or more.

10 . The air cleaner for the stratified scavenging two-stroke internal combustion engine of claim 9 , wherein the channel length of the extension channel is 120 mm or more.

11 . The air cleaner for the stratified scavenging two-stroke internal combustion engine of claim 9 , wherein the opening portion is located in a vicinity of the main nozzle.

12 . The air cleaner for the stratified scavenging two-stroke internal combustion engine of claim 10 , wherein the opening portion is located in a vicinity of the main nozzle.

13 . The air cleaner for the stratified scavenging two-stroke internal combustion engine of claim 9 , wherein the opening portion is located between the carburetor and the engine body.

14 . The air cleaner for the stratified scavenging two-stroke internal combustion engine of claim 10 , wherein the opening portion is located between the carburetor and the engine body.

15 . An intake method of a stratified scavenging two-stroke internal combustion engine configured to feed a combustion chamber with first leading air and subsequently with air-fuel mixture from a crank chamber in a scavenging stroke of the engine,
wherein the engine has an air channel for feeding purified air filtered through an cleaner element to an engine body, an air-fuel mixture channel for feeding the purified air to a carburetor to generate air-fuel mixture with fuel from a main nozzle in the carburetor, and feeds the air-fuel mixture to the crank chamber, and an opening portion making communication between the air channel and the air-fuel mixture channel, the opening portion being located in a vicinity of the main nozzle, wherein one of the air channel and the air-fuel mixture channel is longer than the other of the air channel and the air-fuel mixture channel when viewed in an upstream side of the opening portion, and wherein the intake method comprises a first step for generating air flow in in the air channel, a second step for generating air-fuel mixture flow in the air channel, a third step for making contact of the air flow and the air-fuel mixture flow through the opening portion to make pressure fluctuations of these flows to interfere with each other and thereby decrease a pressure fluctuation in a vicinity of the main nozzle.

16 . The intake method of the stratified scavenging two-stroke internal combustion engine of claim 15 ,
wherein the third step is performed in an operation state where the engine rotates at a high speed.

Assignees

• Yamabiko Corp

Inventors

• Osawa Hisato
• Yamazaki Takahiro
• Tsunoda Hidekazu
• Kobayashi Yuuta

Classifications

• F02M35/1019

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

• F02B17/00 Primary

  Engines characterised by means for effecting stratification of charge in cylinders · CPC title

• F02B2075/025

  two · CPC title

• F02M35/10078

  Connections of intake systems to the engine · CPC title

• F02M19/081

  Shape of venturis or cross-section of mixture passages being adjustable · CPC title