Internal-combustion engines – Two-cycle – Rear compression
Reexamination Certificate
2001-07-06
2003-03-11
Kamen, Noah P. (Department: 3747)
Internal-combustion engines
Two-cycle
Rear compression
Reexamination Certificate
active
06530349
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a two-cycle internal combustion engine configured to prevent blow-by of an air-fuel mixture in a combustion engine for enhancing the combustion stability, fuel consumption, and exhaust gas purifying performance. In particular, the present invention is directed to a two-cycle internal combustion engine in which a chamber portion is disposed adjacent to a combustion chamber, a communication passage is provided between the combustion chamber and the chamber portion, and a control valve for openably/closably controlling the communication passage is disposed in the communication passage, wherein fuel or an air-fuel mixture is supplied into the combustion chamber via the communication passage.
2. Description of Background Art
In conventional two-cycle internal combustion engines, a blow-by phenomenon often occurs, wherein an air-fuel mixture supplied into the combustion chamber via the crank chamber is discharged through the exhaust passage. To solve such a problem, the present applicant has disclosed a two-cycle internal combustion engine in Japanese Patent Laid-open No. Hei 10-325323.
FIG. 12
of the present invention is a longitudinal sectional view of the internal combustion engine disclosed in the above-described document, and
FIG. 13
is a horizontal sectional view cut along a cross-sectional plane passing through the rotary valve shown in FIG.
12
. Referring to these figures, a communication passage for communicating a combustion chamber
013
to a chamber portion
029
is provided in a cylinder block
003
, and a control valve for openably/closably controlling the communication passage is disposed in the communication passage. The communication passage is composed of two first communication passages
030
for allowing high compression gas to flow from the combustion chamber
013
to the chamber portion
029
, and one second communication passage
033
for allowing an air-fuel mixture to flow from the chamber portion
029
to the combustion chamber
013
. The control valve is composed of two first control valves
038
provided in the first communication passages
030
, and one second control valve
037
provided in the second communication passage
033
.
The first control valves
038
open the first communication passages
030
nearly at a point of time when an exhaust opening is closed. The first control valves close the first communication passages
030
at a mid point in the compression stroke. The second control valve
037
opens the second communication passage
033
nearly at a point of time when a scavenging opening is closed and closes the second communication passage
033
before the first communication passages
030
are closed at the mid point in the compression stroke. Reference numeral
036
designates a rotary valve having, in the peripheral portion, cutouts functioning as the first control valves
038
and the second control valve
037
. Reference numeral
031
designates an opening, on the combustion chamber side, of each of the first communication passages
030
, i.e., high compression gas intake opening.
032
is an opening, on the chamber portion side, of each of the first communication passages
030
.
034
is an air-fuel mixture supply opening, opened on the combustion chamber side, of the second communication passage
033
. Furthermore,
035
is an opening, on the chamber portion side, of the second communication passage
033
.
A pair of right and left fuel injectors
041
are mounted in the cylinder block
3
in such a manner as to be disposed on both sides of the chamber portion
029
in the lateral direction. Immediately before the second control valve
037
opens the second communication passage
033
, fuel injected from the fuel injectors
041
is obliquely streamed, from below, in an air-fuel mixture forming space
044
(see
FIG. 12
) formed by the cutout functioning as the second control valve
037
. To be more specific, the fuel is streamed at an approximately central portion of the second communication passage
033
(see FIG.
13
).
The air-fuel mixture is formed as follows: namely, when the second control valve
037
opens the second communication passage
033
along with rotation of the rotary valve
036
, high compression gas charged in the chamber portion
029
flows in the second communication passage
033
from the chamber side opening
035
of the second communication passage
033
, to be mixed with standby fuel. The air-fuel mixture thus formed is then press-fed by high pressure in the chamber portion
029
, to be injected from the air-fuel supply opening
034
into the combustion chamber
013
.
The internal combustion engine of this type, at the initial state of scavenging, the scavenging is performed only by air, and therefore, fuel (rich air-fuel mixture) press-fed to the combustion chamber by means of the above means flows in the combustion chamber having been sufficiently scavenged with air, to thereby form an air-fuel mixture having a suitable concentration in the combustion chamber. The air-fuel mixture thus formed is desirably burned in the combustion chamber. As a result, the engine of this type is advantageous in attaining high level fuel consumption performance and high exhaust gas purifying performance.
According to the above-described background art internal combustion engine, fuel is injected from the fuel injectors
041
directly toward the air-fuel mixture forming space
044
formed by the cutout functioning as the second control valve
037
, and the fuel injection begins immediately before the second control valve
037
opens the second communication passage
033
. Accordingly, part of the stream of fuel strongly sprayed, from below, from the fuel injectors
041
to the rotary valve
036
may be often impinged on the bottom of the groove (cutout) of the rotary valve
036
, to be splashed therefrom in the lateral direction, with a result that the splashed fuel may be often scattered in the chamber portion
029
to adhere on the inner wall of the chamber portion
029
. The amount of fuel adhering on the inner wall of the chamber portion
029
causes an error to the weighed amount of fuel supplied from the fuel injectors
041
. To cope with such an inconvenience, according to the background art internal combustion engine, it has been required to supply a larger amount of fuel, capable of compensating for the amount of fuel adhering on the inner wall of the chamber portion
029
. An object of the present invention is to eliminate the scattering of fuel in the chamber portion
029
due to impingement of the stream of fuel on the rotary valve.
SUMMARY OF THE INVENTION
To solve the above problem, according to the present invention, there is provided a two-cycle internal combustion engine including a combustion chamber; a chamber portion adjacent to the combustion chamber; a communication passage between the combustion chamber and the chamber portion; and a control valve, provided in the communication passage, for opening the communication passage nearly at a point of time when a scavenging opening is closed and closing the communication passage at a mid point in the compression stroke, wherein an air-fuel mixture flows from the chamber portion side into the combustion chamber via the communication passage by operating the control valve. The above two-cycle internal combustion engine is characterized as follows:
(1) A portion, on the chamber portion side, of the communication passage is taken as a gas passage for communicating the control valve to the chamber portion, and a fuel injector for injecting fuel is provided at a mid point in the gas passage via a connection passage in such a manner as to be directed to the inner wall surface of the gas passage while being slightly tilted toward the control valve.
With this configuration, since fuel is injected toward the control valve but is not directly impinged on the control valve, it is possible to reduce the degree of scattering of the fuel on the chamber portion side due to splashing of th
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
Kamen Noah P.
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