JPS61197712A - 2-cycle laminar scavenging internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce blow-by loss of fresh air by supplying mixture forcibly sent to a scavenging path from a carbureter through to a crank chamber into a cylinder as scavenging flow separated into mixture having different fuel concentration through the scavenging path and a scavenging hole. CONSTITUTION:Mixture of air prepared by a carbureter and gasoline flows into a crank chamber 3 through an intake pipe 6. Here it receives turbulence and centrifugal force through a balancer 2, a crankshaft, etc. and is urged against the inner wall of the crank chamber 3. Then, fuel liquid drops, grains and the like in fuel flow into a sub-chamber 5 through a thin groove 4. Thus, rich mixture is formed in the sub-chamber 5 and lean mixture in the crank chamber 3. And while scavenging is carried out by the lean mixture, the rich mixture is supplied to a position remote from a scavenging hole to control blow-by of fuel. Thus, the blow-by loss of fresh air is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stratified scavenging crankcase compression two-stroke internal combustion engine.

In a two-stroke internal combustion engine with a carburetor, the vaporization conditions for the air-fuel mixture supplied from the carburetor into the cylinder are dominated by cylinder and crank nurse O temperature conditions, but even in air-cooled engines with relatively high temperatures, the crank It is observed that the air-fuel mixture in the nurse and scavenging passages contains many liquid fuel particles and liquid films.

The present invention visually observes the flow state of the air-fuel mixture as it is forced into the scavenging passage from the carburetor through the crank chamber, and separates this into air-fuel mixtures with different fuel concentrations.
Laminar #i1 air is achieved by supplying air into the cylinder through the scavenging passage and scavenging holes, and blowing out fresh air makes it possible to reduce loss.

An object of the present invention is to reduce the fuel consumption of the engine and the amount of unburned hydrocarbons in the exhaust gas by reducing the fresh air blowout.

The main structure of the present invention is that in a two-cycle crank chamber compression internal combustion engine, a sub-chamber is formed in the circumferential direction of the crank chamber wall so that the crank chamber is recessed, and the sub-chamber and the crank chamber are separated by narrow grooves or many small holes. It has a structure in which a part of it has an enlarged communication hole to allow the flow of scavenging air from the main crank chamber.This allows the fuel mixture of any air-fuel ratio to be supplied to the crank chamber. The centrifugal force generated by the rotating movement of the big end shaft and the balancer forms liquid fuel or a mixture of fuel density in the subchamber, inevitably creating a lean air-fuel ratio in the crankcase. The structure is such that different rich and lean mixtures can be reliably generated automatically and continuously in the same casing.Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a vertical cross-section of the exhaust port center of a two-stroke gasoline engine with a carburetor and scavenging to which the present invention is applied, and Figure 2 shows the crank chamber centered on the scavenging passage, the large end shaft, and the auxiliary chamber. 3 shows the concave-convex shape of the outer wall of the auxiliary chamber in FIG.
44 is a partially enlarged sectional view of the auxiliary chamber. In this embodiment, inside one crankcase (1) there is a main crank chamber (9) in which the crank balancer (2) rotates, and a slit-like narrow groove (4 ) communicates with the auxiliary chamber (5
) is formed.

When this engine is in operation, the air and gasoline mixture, which has been heated to an excess of 11 m by the carburetor, passes through the intake pipe (6) and into the crank chamber (
However, due to the strong turbulent flow and centrifugal force generated by the crankshaft, etc., the air-fuel mixture is directed toward the wall surface (in the radial direction) of the crank chamber. In this case, it is obvious that droplets and particles with gravity in the air-fuel mixture are greatly affected by centrifugal force, but in conventional engines, liquid fuel on the inner wall surface is generated as the crank rotates. Due to the strong turbulence that occurs, the mixture is sequentially vaporized and converted into gas and then supplied into the cylinder through the scavenging passage, and the air-fuel mixture supplied into the cylinder through the scavenging hole in each cycle becomes a mixture with almost uniform particles, which increases the fuel density. This is followed by layered N air.

On the other hand, in the present invention, fuel droplets, particles, etc. with gravity that are pushed against the inner wall by centrifugal force in the crank chamber (4) flow into the subchamber (5) through the narrow groove (4), and The inside of the chamber is communicated with the crank chamber through a narrow groove, so the strong turbulence caused by the rotation inside the crank chamber is attenuated by the narrow groove.This reduces the fuel density in the subchamber (5). It is now possible to create a rich mixture, and the fuel density in the main crankcase is necessarily low.

The droplet fuel pushed from the main chamber (5) flows into the lower part of the subchamber into the auxiliary chamber (5) and the inner and outer m1 (6) to prevent liquid fuel from accumulating, and at the same time, to keep the droplet fuel O during scavenging. □In order to promote this, it is effective to form it in a multi-stage or uneven shape (7). Also, the communication area between the main chamber and the sub-chamber near the intake port (
The mark is designed to flow a lean air-fuel mixture from the main chamber (3) into the sub-chamber in the event of air loss to promote the vaporization of the tinned fuel in the sub-chamber. There is.

The rich air-fuel mixture or liquid film fuel, etc. generated in the subchamber in this way is supplied into the cylinder from the rich air-fuel mixture scavenging passage (9) which opens on the side opposite to the exhaust from the waste inlet (8). be.

In other words, rare book confusion Gohata 1-□-1-龜□□-+--Torii Hajime□j
--It is possible to perform rational scavenging by supplying air to a location far from the snow and controlling fuel blow-through. - Conventional fuel injection method to prevent fuel blow-through
□ requires only air in the crank chamber, which requires a separate double-track lubrication mechanism, which causes problems with lubrication of the small and large end shafts, bearings, seals, pistons, etc. However, in the present invention, there is always air in the crank chamber. Another advantage of the present invention is that continuous 'am' D operation can be performed even in a simple fuel mixture lubrication system due to the presence of an air-fuel mixture.
Regarding volumetric matching, as long as the narrow grooves (4) and the subchamber (9) are not made too large, the basics of the present invention are that the fuel consumption rate and HO in the exhaust gas can be reduced by the effect of thinning of the iris. A feature of the present invention is that the production cost does not increase.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of the center of the exhaust port of a carburetor crank compression two-cycle engine to which the present invention is applied, FIG. 2 is a cross-sectional view of the crank body including the crank large end shaft at the center of the bleed hole, and FIG.
FIG. 4 is a partially enlarged sectional view of the auxiliary chamber. In the figure, (1)--Crank case, (2)--Palancer, (3)--Crank main chamber, (4)--Slit-like narrow groove, (5)--Sub chamber, (6)...Inhalation path,
(7)...Irregularities on the outer wall of the sub-chamber, (8)...Scavenging air communication port, (9)...Reed valve, (10)...Protrusions on the outer wall of the sub-chamber. Figure 1

Claims (2)

[Claims] (1) Numerous small holes around the radial inner wall of the crank chamber.
Alternatively, an auxiliary chamber is formed that is communicated with a groove, and the fuel and air supplied into the crank chamber are centrifugally separated by the rotational movement of a parancer rotated by the crank movement of the engine and its centrifugal force. , a mixture with high fuel density is generated in the outer sub-chamber, and the mixture in the main crank chamber and the sub-chamber are supplied in layers as rich and lean mixtures into the cylinder through scavenging air passages. A distinctive crank chamber compression two-stroke internal combustion engine. (2) The two-stroke stratified scavenging internal combustion engine according to claim (1), which has a fuel supply device operated mechanically, hydraulically, or electrically, and mainly supplies fuel into the pre-chamber.