Two-cylinder overhead-valve V-engine

Details Two-cylinder overhead-valve V-engine Two-cylinder overhead-valve V-engine

2001-09-04

2003-01-28

Kamen, Noah P. (Department: 3747)

Internal-combustion engines

Multiple cylinder

Cylinders radiating

C123S090250

Reexamination Certificate

active

06510823

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a two-cylinder overhead-valve V-engine and, more specifically, to improvements in the arrangement of an air intake passage and a cooling water passage in a water-cooled two-cylinder overhead-valve V-engine.
2. Description of the Related Art
FIG. 11
shows a conventional water-cooled two-cylinder overhead-valve V-engine in which a head cover and a carburetor are removed. An intake valve rocker arm
102
and an exhaust valve rocker arm
103
are placed on the cylinder head
101
of each cylinder. The intake valve rocker arm
102
has one end in contact with an intake valve and the other end in contact with an intake valve driving push rod
106
. The exhaust valve rocker arm
103
has one end in contact with an exhaust valve
107
and the other end in contact with an exhaust valve driving push rod
108
.
The cylinder head
101
is provided with an air intake port
110
in one end part thereof on one side with respect to a direction parallel to the axis O
1
of a crankshaft, and an exhaust port
111
in the other end part thereof on the other side with respect to the direction parallel to the axis O
1
of the crankshaft. A water jacket has an outlet
113
formed in a part of the cylinder head
101
on the side of the air intake port
110
.
An intake manifold
120
is disposed on the side of the air intake port
110
and has an air intake passage
131
and a cooling water passage
121
adjacent to the air intake passage
131
. The air intake passage
131
has one end directly connected to the air intake port
110
of the cylinder head
101
of one of the two cylinders, and the other end connected through a thermostat case
115
to the air intake port
110
of the cylinder head
101
of the other cylinder. The cooling water passage
121
has one end directly connected to the outlet
113
of the water jacket of one of the two cylinders, and the other end connected through the thermostat case
115
to the outlet
113
of the water jacket of the other cylinder.
The thermostat case
115
includes a first cooling water inlet
116
connected to the outlet of the water jacket, a second cooling water inlet
122
connected to the cooling water passage
121
of the intake manifold
120
, a first cooling water outlet
125
connected to a water pump by a bypass pipe
124
, a second cooling water outlet
118
connected to a cooling water return opening of a radiator, and a thermostat
114
. The thermostat
114
measures the temperature of cooling water at the outlet of the water jacket, connects the cooling water passage
121
to the bypass pipe
124
when the measured temperature is lower than a set temperature or to the radiator when the measured temperature is not lower than the set temperature.
The intake manifold
120
is provided in its upper middle part with an inlet opening
137
. The inlet opening
137
is connected to a carburetor, not shown, disposed above the intake manifold
120
.
FIG. 12
is an enlarged sectional view taken on line XII—XII in FIG.
11
. Push rods
106
and
108
are extended in substantially parallel to each other into the cylinder head
101
and a cylinder block
140
. The lower ends of the push rods
106
and
108
respectively rest on tappets
141
engaging a camshaft
142
.
As shown in
FIG. 11
, when the air intake port
110
and the cooling water outlets
113
are formed in the end parts of the cylinder head on one side with respect to the direction parallel to the axis O
1
of the crankshaft, and the air intake ports
110
and the cooling water outlets
113
are connected by the intake manifold
120
disposed on the side of the air intake ports
110
, the engine inevitably has a big dimension along the direction of the axis O
1
of the crankshaft, and the air intake passage between the carburetor and the air intake port
110
of each cylinder head
101
is inevitably long. An art relating with the present invention is disclosed in Japanese Laid-Open Publication No. Hei 10-159510.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a water-cooled two-cylinder overhead-valve V-engine of compact construction having short air intake passages by changing opening positions of air intake ports and cooling water outlets of water jackets so as to use a bank space effectively.
The present invention a two-cylinder overhead-valve V-engine includes: a pair of cylinders arranged so as to form a V-shape in which a V-bank is formed, each of said cylinders including a cylinder head with an intake valve and an exhaust valve; a camshaft disposed below said V-bank in parallel to an axis of a crankshaft; intake valve rocker arms for operating said intake valves, respectively; exhaust valve rocker arms for operating said exhaust valves, respectively; and push rods for operating said intake valve rocker arms and said exhaust valve rocker arms, respectively, said push rods being connected to said camshaft by tappets, respectively, each pair of said push rods for each of said cylinders being extending gradually away from each other toward each of valve rocker arm chambers in which said valve rocker arms are housed, wherein, between each pair of said push rods for each of said cylinders, each of air intake passages with air intake ports for said cylinder heads is formed, each of said air intake ports being formed so as to open into said V-bank, each of said air intake ports being connected by each of said air intake passages formed in said V-bank to a carburetor disposed in said V-bank.
Since the V-bank can be used effectively for installing the intake manifold and the carburetor, this two-cylinder overhead-valve V-engine has a comparatively small dimension in the direction of an axis of a crank shaft, and the carburetor can be connected to the air intake ports of the cylinder heads by short, straight air intake passages. Consequently, the passage resistance of the air intake passages is small. The engine is able to respond quickly to throttle opening adjustment. Moreover, the stagnation of the fuel and the oil in the air intake passages can be prevented.
Preferably, together with said air intake ports, cooling water outlets of water jackets for said cylinders are formed so as to each open between each pair of said push rods for each of said cylinders, said cooling water outlets of said water jackets being connected by a cooling water passage adjacent to said air intake passages disposed in said V-bank.
Accordingly, part of the cooling water pipe system can be disposed in the V-bank so as to be simplified with the result that the two-cylinder overhead-valve V-engine can be formed in compact construction. Since the cooling water passage through which the cooling water heated in the water jacket flows is formed adjacently to the intake air passages, walls forming the intake air passages are heated to promote the gasification of the fuel flowing through the air intake passages.
Preferably, said cooling water passage connecting said cooling water outlets of said water jackets is provided with a cooling water outlet connected to a radiator.
Accordingly, the cooling water pipe system can be formed in a simple, compact arrangement and the engine can be formed in compact construction.


REFERENCES:
patent: 4054108 (1977-10-01), Gill
patent: 4058092 (1977-11-01), Hikosaka et al.
patent: 4449491 (1984-05-01), Tsuchiyama et al.
patent: 4455975 (1984-06-01), Kume
patent: 4662322 (1987-05-01), Tamba et al.
patent: 4739675 (1988-04-01), Connell
patent: 4852527 (1989-08-01), Beardmore et al.
patent: 5235942 (1993-08-01), Olmr
patent: 5732670 (1998-03-01), Mote, Sr.
patent: 5813377 (1998-09-01), Matsunaga
patent: 5937804 (1999-08-01), Kaminski
patent: A 10-159510 (1998-06-01), None

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