Marine propulsion – Means for accomodating or moving engine fluids – Means for handling exhaust gas
Reexamination Certificate
2000-03-28
2001-09-18
Basinger, Sherman (Department: 3617)
Marine propulsion
Means for accomodating or moving engine fluids
Means for handling exhaust gas
C181S232000
Reexamination Certificate
active
06290557
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an exhaust system for a jet propulsion boat that exhausts engine exhaust gas into water.
2. Background Art
A jet propulsion boat is known in which a rider rides a saddle-type seat, and controls the vehicle by a steering handlebar having an accelerator lever on a right end portion of the steering handlebar, and a decelerator lever on a left end portion of the steering handlebar. An exhaust system for a conventional jet propulsion boat, an “Engine Exhaust system of Small-Sized Ship,” is described in Japanese Unexamined Patent Publication No. 8-119196. This type of exhaust system will be described with reference to
FIGS. 8 and 9
of this application.
FIG. 8
is a plan view of a conventional exhaust system for a jet propulsion boat. An engine
101
is mounted below a steering handlebar
100
, an impeller (not illustrated) of a jet propulsion device is attached to a drive shaft
102
extending rearwardly from engine
101
, and an exhaust system
105
is provided at the engine
101
.
An exhaust pipe
106
extends rearwardly from a left side portion of the engine
101
, and a muffler is connected to an outlet of the exhaust pipe
106
arranged on the left side of the jet propulsion device
103
. A connecting pipe
108
having an inverse U shape is connected to an outlet of the muffler
107
and extends to the right side by passing over the jet propulsion device
103
. An auxiliary muffler
109
is connected to an outlet of the connecting pipe
108
and is arranged on the left side of the jet propulsion device
103
. An exhaust pipe
110
is connected to an outlet of the auxiliary muffler
109
.
The jet propulsion boat is propelled by jetting water sucked from a hull bottom rearwardly from a nozzle
112
by rotating the impeller of the jet propulsion device
103
by the engine
101
. Exhaust gas from the engine
101
is exhausted from the exhaust pipe
110
into a casing of the jet propulsion device
103
by flowing through the exhaust pipe
106
to the muffler
107
. The gas then flows from the muffler
107
through the connecting pipe
108
to the auxiliary muffler
109
, then out the exhaust pipe
110
.
FIG. 9
is a sectional view taken along a
9
—
9
line of FIG.
8
.
FIG. 9
shows the muffler
107
and the auxiliary muffler
109
respectively arranged at portions
113
and
114
of the hull bottom on the left side and the right side of the jet propulsion device. The muffler
107
and the auxiliary muffler
109
are connected by the connecting pipe
108
having an inverse U shape.
The height H of a top portion
108
a
of the connecting pipe
108
can be made sufficiently high to prevent water from accidentally entering the muffler
109
from crossing over the connecting pipe
108
and entering the engine
101
. Accordingly, the connecting pipe
108
is generally referred to as a water lock pipe.
However, since the auxiliary muffler
109
is attached between the connecting pipe
108
and the exhaust pipe
110
, when water enters the exhaust pipe
110
and an exhaust port of the exhaust pipe
110
, there is the concern that water which has entered the exhaust pipe
110
may also enter the auxiliary muffler
109
.
When water enters the auxiliary muffler
109
and the volume of the auxiliary muffler
109
is reduced, the noise reduction capacity of the auxiliary muffler is deteriorated, and exhaust noise increases.
It therefore is an object of the present invention to provide an exhaust system capable of sufficiently reducing exhaust noise.
SUMMARY OF THE INVENTION
In order to resolve the above-described problem and to achieve other advantages not present in conventional exhaust systems, there is provided an exhaust system in a jet propulsion boat. The jet propulsion boat has a jet propulsion device for jetting water sucked from a hull bottom rearward, and an engine for driving the jet propulsion device. A muffler is connected to the engine by an exhaust pipe. A connecting pipe having an inverse U shape extends from either side of an auxiliary muffler, with the auxiliary muffler located at the highest point along the connecting pipe.
In this configuration, when water enters the exhaust pipe, the water is blocked by the connecting pipe and does not enter the auxiliary muffler attached to the top portion of the connecting pipe. Water is therefore not stored in the auxiliary muffler and the noise reduction capacity of the auxiliary muffler is not reduced.
The auxiliary muffler is a horizontal cylinder type muffler, both ends of a cylindrical body of which being closed by lid plates. A pair of the lid plates are provided with an exhaust inlet and an exhaust outlet, and levels of a bottom of the exhaust inlet and a bottom of the exhaust outlet are substantially coincident with a level of a bottom of the cylindrical body.
Accordingly, when water accidentally enters the auxiliary muffler, water is not stored in the cylindrical member because water exits the cylindrical member via the exhaust inlet and the exhaust outlet. The noise reduction capacity of the auxiliary muffler is therefore unaffected.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 4713029 (1987-12-01), Ford
patent: 5196655 (1993-03-01), Woods
patent: 5746630 (1998-05-01), Ford et al.
patent: 5824972 (1998-10-01), Butler
patent: 6071156 (2000-06-01), Platzer et al.
patent: A8119196 (1996-05-01), None
Basinger Sherman
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
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