Internal-combustion engines – Lubricators – Crankcase – pressure control
Reexamination Certificate
2001-07-03
2003-06-24
Kamen, Noah P. (Department: 3747)
Internal-combustion engines
Lubricators
Crankcase, pressure control
Reexamination Certificate
active
06581563
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of lubricating a sliding portion between a cylinder and a piston of a two-cycle internal combustion engine configured to prevent blow-by of an air-fuel mixture in a combustion chamber, thereby enhancing a fuel consumption and an exhaust purifying performance.
2. Description of the Relevant Art
FIGS. 9 and 10
show a prior art two-cycle internal combustion engine disclosed in Japanese Patent Laid-open No. Hei 10-325313.
FIG. 9
is a longitudinal sectional view of an essential portion of the engine and
FIG. 10
is a horizontal sectional view of an essential portion of the engine.
In the two-cycle internal combustion engine of this type, air is sucked and compressed in a crank chamber and the scavenging is performed by the compressed air; after the scavenging only by air is ended, a high compression gas is charged from a combustion chamber
013
into a chamber portion
020
provided adjacently to a cylinder
005
; and an air-fuel mixture is formed by the high compression gas and fuel and is injected into the combustion chamber
013
.
In these figures, reference numeral
003
designates a cylinder block;
005
is a cylinder provided in the cylinder block
003
; and
020
is a chamber portion provided adjacently to the cylinder
005
. The cylinder
005
is connected to the chamber portion
020
via a communication passage
030
. A rotary valve
040
for opening/closing the communication passage
003
is provided in a mid portion of the communication passage
030
.
The communication passage
030
has one cylinder side passage portion positioned on the cylinder
005
side from the rotary valve
040
, and two chamber portion side passage portions positioned on the chamber portion
020
side from the rotary valve
040
. In the figures, reference numeral
031
designates a cylinder side opening of the communication passage
030
, and reference numeral
032
designates each of two chamber portion side openings of the communication passage
030
. A fuel injector (not shown) is mounted in each of two mounting holes
036
formed at ends of intermediate portions of the two chamber portion side passage portions of the communication passage
030
.
The rotary valve
040
, disposed in such a manner as to cross the communication passage
030
, is composed of a first control valve
041
configured as a deeper cutout and a second control valve
042
configured as a shallower cutout. The second valve
042
is disposed in front of the first control valve
041
in the rotational direction while being continuous to the first control valve
041
. The first control valve
041
controls the flow of a high compression gas, and the second control valve
042
controls the flow of an air-fuel mixture.
The switching from the flow of an air-fuel mixture to the flow of a high compression gas is dependent on a balancing relationship between a pressure in the combustion chamber
013
and a pressure in the chamber portion
020
. This is because the communication passage
030
is commonly used for charging the high compression gas in the chamber portion
020
and for injecting the airfuel mixture from the chamber portion
020
. To be more specific, when the pressure in the combustion chamber
013
becomes higher than the pressure in the chamber portion
020
, the flow in the communication passage
030
is switched from the flow of the air-fuel mixture into the flow of the high compression gas. Nearly at this time, the flow control by the rotary valve
040
is shifted from the flow control of the air-fuel mixture by the second control valve
042
to the flow control of the high compression gas by the first control valve
041
.
In the figures, reference numeral
014
designates each of four scavenging passages, and
021
also designate a scavenging passage;
015
is a cylinder side opening of the scavenging passage
014
, and
022
is a cylinder side opening of the scavenging passage
021
;
016
is an exhaust passage and
017
is a cylinder side opening of the exhaust passage
016
; and
013
is a combustion chamber.
Referring to
FIG. 10
, two lubricating oil supply holes
050
for lubricating a sliding portion between the cylinder
005
and the piston
006
are provided on both sides of the communication passage
030
. Cylinder side openings
051
of both the lubricating oil supply holes
050
are formed in the inner wall surface of the cylinder
005
at positions located on both sides of the cylinder side opening
031
of the communication passage
030
in the circumferential direction and located between the opening
031
of the communication passage
030
and the scavenging openings
015
in the height direction. Lubricating oil, which is fed in the lubricating oil supply holes
050
by an oil pump (not shown) connected to outer openings
052
of the lubricating oil supply holes
050
, flows from the openings
051
of the lubricating oil supply holes
050
into the cylinder bore
005
.
Two lubricating oil supply holes
055
having openings
056
are provided on both sides of the cylinder side opening
017
of the exhaust passage
016
as needed. Lubricating oil, which is fed in the lubricating oil supply holes
055
by an oil pump (not shown) connected to outer openings
057
of the lubricating oil supply holes
055
, flows from the openings
056
of the lubricating oil supply holes
055
into the cylinder bore
005
.
In the above-described prior art internal combustion engine, an air-fuel mixture containing gasoline as fuel is injected from the cylinder side opening
031
of the communication passage
030
. The gasoline contacts a portion near the opening
031
of the communication passage
30
of the inner all of the cylinder
005
, and a portion facing to the opening
031
of the communication passage
030
of the outer peripheral surface of the piston
006
. As a result, the lubricating oil adhering on the inner wall of the cylinder
005
and on the outer peripheral surface of the piston
006
is often carried away or washed away by the gasoline. As a result, according to the prior art engine, it is difficult to maintain the lubricating performance, and to prevent lubricating oil adhering particularly on a portion on the communication passage side of the piston
006
from being all carried away by gasoline. Therefore, in accordance with the prior art, it has been necessary to supply an excessive amount of lubricating oil from the lubricating oil supply holes
050
.
SUMMARY OF THE INVENTION
It is an object of the present invention is to solve one or more of the drawbacks of the prior art's internal combustion engines. To this end, the present invention provides a lubricating system for a two-cycle internal combustion engine, which is capable of sufficiently and effectively lubricating the engine by supplying a smaller amount of lubricating oil.
According to the present invention, there is provided a method of lubricating a two-cycle internal combustion engine which includes a combustion chamber, a chamber portion, a communication passage provided between the combustion chamber and the chamber portion. One end of the communication passage is opened in an upper portion of a cylinder as a constituent component of the combustion chamber, and a control valve for controlling the opening/closing of the communication passage is provided.
A high compression gas is charged in the chamber portion and an air-fuel mixture is injected from the chamber portion into the combustion chamber via the communication passage by way of the high compression gas stored in the chamber portion.
A lubricating system in accordance with the present invention is characterized as follows:
(1) A lubricating oil supply hole is provided in the cylinder. The lubricating oil supply hole has a cylinder side opening positioned in the same direction as the direction in which a cylinder side opening of the communication passage is positioned, as seen from the center line of the cylinder. With this configuration, since the piston (or the piston ring
Ali Hyder
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
Kamen Noah P.
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