Two-cycle engine

Details Two-cycle engine Two-cycle engine

1999-12-10

2001-08-28

Kamen, Noah P. (Department: 3747)

Internal-combustion engines

Two-cycle

Rear compression

C123S0740AP

Reexamination Certificate

active

06279521

ABSTRACT:

BACKGROUND OF THE INVENTION AND RELATED ART
This invention concerns two-cycle engines, and more particularly loop scavenging type two-cycle engines with improvements made to scavenging passages.
This type of loop scavenging two cycle engine
51
known in the prior art has the construction shown in
FIG. 12
wherein scavenging passages
56
extend upward from the top of a crank chamber
55
inside the sidewall of a cylinder
53
, the passages
56
connect with scavenging charge ports
57
inside the cylinder
53
, and the piston
54
is lowered to charge the fuel mixture from the inlet port into the crank chamber
55
and to the cylinder
53
from the scavenging charge ports
57
via the scavenging passages
56
. Such a construction is disclosed, for instance, in Japanese Patent Publication Sho60-48609.
Another construction of a two-cycle engine is disclosed in Japanese Utility Model Kokai Sho57-13217 wherein a passage from the bottom of the crank chamber to the top surface of the crankcase is formed through the crankcase sidewall, and the passage is connected to the scavenging passage on the cylinder side to supply the fuel mixture to the crank chamber to the cylinder.
Of the engines discussed above, the engine shown in
FIG. 12
has the inner diameter (the cross sectional area in the horizontal direction) of the scavenging passage
56
formed substantially vertical inside the sidewall of the cylinder
53
from above the crank chamber which is substantially the same as that of the area of the opening of the scavenger port
57
. Therefore, as the fuel mixture forced outside the crank chamber
55
rapidly flows into the cylinder
53
from the scavenging charge port
57
, a portion of unburned fuel mixture is emitted to the atmosphere from the outlet port
59
with the exhaust gas, the emitted amount being more than 30% of the scavenging gas flowing into the cylinder
53
. This is criticized as hazardous to the natural environment.
The engine disclosed in Japanese Utility Model Kokai No. Sho57-13217 has a drawback in that the smooth supply of scavenging gas is prevented or the supply to the cylinder is altogether suspended by the negative pressure inside the scavenging passages as the rotational speed of the engine increases and the scavenging passages resonate.
SUMMARY OF THE INVENTION
In view of the problems encountered in the prior art loop scavenging engines as discussed above, this invention aims to offer engines adapted for resource preservation and environment conservation by improving combustion efficiency through controlling emission of unburned scavenging gas.
The two-cycle engine according to the present invention comprises a scavenging passage on the cylinder side and another scavenging passage on the crankcase side for supplying scavenging gas to the cylinder, and the said engine is characterized in that the passage on the cylinder side comprises a passage inside the cylinder sidewall having the inner diameter substantially the same as that of the opening of the scavenging charge port, and the scavenging passage on the crankcase side consists of a space provided between the inner peripheral surface at the top end of the crankcase and the outer peripheral surface of the piston and a connection means provided between the top end of the space and the lower end of the said scavenging passage on the cylinder side.
When the fuel mixture in the crank chamber is supplied to the scavenging passage on the cylinder side from the passage on the crankcase side with the lowering of the piston in this engine, the rapid fuel mixture flow from the passage on the cylinder side to the cylinder is restrained and the flow slows down restricted by the narrow space and the connection means between these passages. As a result, not only the fuel mixture is smoothly supplied, but also the amount of unburned gas emitted into the atmosphere with exhaust gas is decreased to less than half of the prior amount.


REFERENCES:
patent: 4378762 (1983-04-01), Ehrlich
patent: 4516540 (1985-05-01), Nerstrom
patent: 4825821 (1989-05-01), Baltz et al.
patent: 4934345 (1990-06-01), Fukuoka et al.
patent: 5740767 (1998-04-01), Kaku et al.
patent: 57-13217 (1982-01-01), None
patent: 60-48609 (1985-10-01), None

Affiliated with

Also associated with

Rating

Two-cycle engine does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Two-cycle engine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two-cycle engine will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2451516