Yamabiko Corporation

Kioritz Corporation

Hidekazu Tsunoda

Takahiro Yamazaki

Hisato Osawa

Takamasa Otsuji

Hisato Ohsawa

Shigeru Sato

Shirou Yamaguchi

Kunimune Kawamura

Shiro Yamaguchi

Shunsuke Ueda

Kazuhiro Tsutsui

Tomoyoshi Kudo

Yuuta Kobayashi

Keita Kamo

Kentaro Matsuo

The efficiency of charging air to a scavenging channel is enhanced by generating a gas flow in a piston groove simultaneously with the piston groove coming into communication with an air port. A piston grooveformed in a peripheral surface of a piston includes a pressure transmission through hole, and the pressure transmission through holeconsistently communicates with a crankcase. In the course of the piston moving up, upon a pressure in the crankcase becoming negative, the negative pressure in the crankcase affects the piston groovethrough the pressure transmission through hole. Consequently, a pressure in the piston grooveis released to the crankcase through the pressure transmission through hole. Upon the piston moving up and the piston groovebeing thereby brought into communication with the air port, air enters the piston groovethrough the air port((III) of FIG.).

Air leading-type stratified scavenging two-stroke internal-combustion engine

To improve the effect of preventing contamination of an element in an air cleaner. An air cleaner includes a first inlet () through which air is fed to an intake system air passage and a second inlet () through which air is fed to an intake system air-fuel mixture passage. An extended passage () leads to the second inlet (), for example. A passage forming member () forming the extended passage () is shaped to surround a periphery of the first inlet (). The passage forming member () forms a blown-back fuel diffusion preventing region () leading to the first inlet ().

Air cleaner for stratified scavenging two-stroke internal combustion engine

To balance a 'low-temperature scavenging effect' and a 'high-temperature scavenging effect.' A scavenging system applicable to a leading-air type two-stroke air-cooled engine has a low-temperature scavenging passage and a high-temperature scavenging passage. The low-temperature scavenging passage has first and second passages and includes scavenging ports at upper end parts thereof. The high-temperature scavenging passage has first and second passages and includes scavenging ports at upper end parts thereof. An air is filled through a piston groove into the passages. The low-temperature scavenging passage has a relatively small capacity. The high-temperature scavenging passage has a relatively large capacity.

Leading-air type two-stroke air-cooled engine

To allow an intake negative pressure to directly act on a fuel outlet formed on a nozzle tube, and to guide a fuel discharged from the fuel outlet in the nozzle tube to the fuel-air mixture passage. A rotary carburetor () has a guide plate member () downstream of a fuel outlet () located in a through-hole (). The guide plate member () has both side edges () away from an inner wall surface () of the through-hole (). The through-hole () is divided by the guide plate member () into a first passage portion () and a second passage portion (). The first passage portion () communicates through a piston groove with a scavenging passage of a cylinder. The fuel discharged from the fuel outlet () is guided by the guide plate member () to the second passage portion () and is supplied through the second passage portion () to a fuel-air mixture passage () of an engine intake system.

Rotary carburetor for two-stroke internal combustion engine

An amount of air taken into an air leading type two-stroke engine is increased to enhance an engine output, and gas emission characteristic deterioration caused by blow-back is inhibited. An inhibition memberis disposed between a choke valvein a full open position and a throttle valvein a full open position. The inhibition memberincludes, for example, a mesh member like a metal mesh. Mixed fuel containing oil is supplied to the air-fuel mixture channel. Numerous pores of the inhibition member(mesh member) are occluded by a membrane of oil components of the mixed fuel. Consequently, entry of a blow-back flow of an air-fuel mixture from the air-fuel mixture channelinto the air channelthrough the numerous pores of the flow inhibition member(mesh member) can be inhibited.

Air leading type two-stroke engine and intake system for same, and carburetor

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.

Suction tube unit of stratified scavenging engine

The certainty of supplying air to a scavenging channel through a piston groove is improved. In a cylinder wall, a gas venting portis formed below and adjacent to a scavenging port. The gas venting portis independent from the scavenging port, and is opened/closed by a piston as each of an air portand the scavenging portis. Upon a piston groovebeing brought into communication with the gas venting portas a result of the piston moving up (FIG.(II)), blown-back gas in a piston groovecan move to a crankcase through the gas venting port. Along with this, air can enter the piston groovefrom the air port

Object It is intended to prevent intrusion of air-fuel mixture into an air cleaner by blow-back in an air-fuel mixture passage of a stratified-scavenging two-stroke engine. Solution The air cleaner () includes a guide member (). A blow-back flow of air () flowing back to the air cleaner () through a first air opening (A) due to blow-back of air is induced to a vicinity of a second air opening (M) by the guide member (). A blow-back flow of air-fuel mixture () occurring in an air-fuel mixture passage () prior to the blow-back phenomenon in an air passage () collides the air flowmoving toward the vicinity of the second air opening (M), and retains the air-fuel mixture near the second air opening (M).

Air cleaner for stratified-scavenging two-stroke internal combustion engine

An air cleaner is used in a two-stroke internal combustion engine to supply an air-fuel mixture passage and a fresh air passage in a carburetor with air cleaned by an air cleaner element. The air cleaner includes an air cleaner base having an air-fuel mixture opening communicating with the air-fuel mixture passage and a fresh air opening communicating with the fresh air passage, and an air guide member provided at the air-fuel mixture opening. The air guide member is configured to curve near the air-fuel mixture opening and extend from there along the air cleaner base, and has a cross section surrounded by a peripheral wall. The air guide member defines a mixture-use air extension passage for air to be added to prepare an air-fuel mixture air-fuel mixture, which extends from a first clean air intake to the air-fuel mixture opening. Blown-back gas from the air-fuel mixture passage hits against the inner wall of the curved portion of the air guide member, and is therefore restricted to flow out of the first clean air intake and leak into the air cleaner. Thereby, harmful emissions in the exhaust gas from the two-stroke internal engine can be reduced.

Air cleaner for two-stroke internal combustion engine and method of tuning the length of air-fuel mixture passage by using the air cleaner

A two-stroke internal combustion engine () is provided with one pair or plural pairs of C-shaped scavenging passageways () of a reverse flow system where scavenging inlet ports () as well as scavenging outlet ports () are both opened to a cylinder bore (), wherein a scavenging introducing passageway () for introducing an air-fuel mixture (K) from a crank chamber () into the scavenging inlet ports () is provided between the cylinder bore and the piston adapted to reciprocatively move up and down in the cylinder bore (), and an effective opening area of the scavenging inlet ports () is gradually decreased due to the piston () in the course of descending stroke of the piston ().

Growing community of inventors

Tokyo, Japan

Hidekazu Tsunoda