Information
-
Patent Grant
-
6802284
-
Patent Number
6,802,284
-
Date Filed
Thursday, April 11, 200222 years ago
-
Date Issued
Tuesday, October 12, 200419 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Argenbright; Tony M.
- Harris; Katrina B.
Agents
-
CPC
-
US Classifications
Field of Search
US
- 123 73 A
- 123 478
- 123 590
- 123 472
- 239 53312
-
International Classifications
-
Abstract
A fuel injection device mounted on a main body of an air-fuel mixture generating device including an electromagnetic driving-type fuel injection valve for injecting, at predetermined times, fuel into an air-intake passageway of an intake system of an internal combustion engine, and a collision plate operationally coupled to the fuel injection valve adapted to be disposed in the air-intake passageway for enabling the injected fuel to collide therewith.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based on Japanese Patent Application Ser. No. 115829/2001, filed Apr. 13, 2001, which is incorporated herein by reference for all purposes and from which priority is claimed.
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a fuel-injection device of electromagnetic driving type, for injecting fuel into an air-intake system of an internal combustion engine at predetermined times, and more particularly, to a fuel injection device adapted to be integrated, as fuel injection means, into an air-fuel mixture generating device equipped with a diaphragm-type fuel pump and designed to be employed in place of an ordinary carburetor.
2. Description of the Related Art
An air-intake system of a small air-cooled two-stroke gasoline engine of crankcase-precompression type (hereinafter, referred to simply as an internal combustion engine), designed to be mounted on a portable working machine such as a chain saw or a brush cutter, frequently employs, as an air-fuel mixture generating device, a floatless diaphragm-type carburetor. The carburetor is ordinarily equipped with a diaphragm-type fuel pump, which is designed to receive fuel and subsequently inject pressurized fuel in conformity with pressure changes (pulsating pressure) inside a crankcase of the internal combustion engine in order to ensure a stable fuel supply to the engine irrespective of the engine posture.
However, it is often difficult to precisely control the air/fuel ratio, i.e., a quantity of fuel relative to a quantity of the intake air, using a diaphragm-type carburetor, and to achieve sufficient fuel atomization and faithful response to the pulsating pressure, thereby making it difficult to effectively take measures for purifying the exhaust gas.
With a view to addressing these problems, an air-fuel mixture generating device, equipped with a fuel injection valve in addition to a diaphragm type fuel pump, has been recently proposed as an alternative to the aforementioned carburetor.
This air-fuel mixture generating device includes a main body similar to the carburetor, and a diaphragm disposed inside the main body. A pulsating pressure chamber, to which the pressure of the crankcase is transmitted, is provided on one side of the diaphragm, and a pump chamber for receiving fuel and then injecting fuel to a fuel passageway is provided on the other side of the diaphragm. The diaphragm is actuated (reciprocating movement) by the pressure changes (pulsating pressure) in the crankcase, resulting from the piston movement, i.e., a decrease in pressure as the piston is moved upward and an increase in pressure as the piston is moved downward. The pressurized fuel is thereby enabled to be fed from the pump chamber to the fuel passageway, and also the fuel inside the fuel passageway is enabled to be pressurized. Simultaneously, the aforementioned fuel injection valve is allowed to open at predetermined times (for example, at the moment of initiating the suction stroke) and remain open for a predetermined time period (for example, 1 to 3 milliseconds), depending on the operative conditions of the internal combustion engine to thereby enable the pressurized fuel in the fuel passageway to be injected into the intake system (for example, an intake passage portion located on a downstream side of a throttle valve) and be mixed with the received air, thereby producing an air-fuel mixture.
However, in such an air-fuel mixture-generating device, insufficient atomization of the fuel that has been injected from the fuel injection valve allows for a substantial portion of the injected fuel to adhere onto a sidewall of the intake passageway without being mixed with the air flowing through the passageway.
Additionally, if fuel atomization is insufficient, the air-fuel mixture becomes non-uniform, thereby badly affecting its combustibility in the internal combustion engine and, thus, the engine performance may deteriorate.
Moreover, even various modifications that have been suggested, such as increasing the supply pressure of fuel (fuel pressure) fed to the fuel injection valve, or decreasing a pore diameter of an injection port of the fuel injection valve, fail to achieve sufficient fuel atomization, and, thus, fail to overcome the aforementioned problems.
For example, in case where the pressurized fuel is fed to the fuel injection valve via a diaphragm-type fuel pump driven by the pressure changes (pulsating pressure) inside a crankcase of an internal combustion engine (e.g., when the aforementioned air-fuel mixture-generating device is employed), a delivery pressure effected by the diaphragm-type fuel pump is relatively low. Thus, when a pore diameter of an injection port of the fuel injection valve is decreased, the injection port is more likely to be clogged with dust, thereby obstructing the feeding of fuel. Accordingly, there exists a need in the art for a fuel injection device capable of enhancing fuel atomization and for an air-fuel mixture generating device equipped with such a fuel injection device, which can overcome the aforementioned disadvantages associated with the prior fuel-injection and air-fuel mixture-generating devices.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a fuel injection device which is capable of effectively enhancing fuel atomization as the fuel is injected from a fuel injection valve without increasing the fuel supply pressure fed to the fuel injection valve, or decreasing a pore diameter of an injection port of the fuel injection valve.
Another object of the present invention is to provide an air-fuel mixture generating device equipped with such a fuel injection device.
These and other objects of the present invention, which will become apparent with reference to the disclosure herein, are attained by the provision of a fuel injection device which includes an electromagnetic driving-type fuel injection valve for injecting fuel into an air-intake passageway of an intake system of an internal combustion engine at predetermined times, the fuel injection valve being provided with a collision plate adapted to be disposed in the air-intake passageway for enabling the injected fuel to collide therewith.
Preferably, the collision plate includes a reflecting surface, disposed downstream of the fuel injection valve, inclined so as to enable the fuel that has collided against the reflecting surface to reflect therefrom and diffuse along the direction of air flow running through the air-intake passageway of the intake system.
The reflecting surface may also be provided with restricting means such as a U-shaped groove for restricting the direction of reflection and diffusion of the fuel that collides with the reflecting surface, directed in line with the direction of the air flowing through the air-intake passageway, as well as in line with a direction intersecting orthogonally with a fuel-injecting direction of the fuel injection valve.
In another embodiment, an air-fuel mixture generating device according to the present invention comprises a main body, a diaphragm-type fuel pump disposed in the main body, a fuel passageway in the main body operationally coupled to the fuel pump for receiving and pressurizing the fuel injected from the fuel pump in conformity with pressure changes inside a crankcase of an internal combustion engine, a fuel injection device mounted on the main body and operationally coupled to the fuel passageway for receiving the pressurized fuel therefrom and injecting the pressurized fuel into an air-intake passageway of an air-intake system of the internal combustion engine, and the fuel injection device comprising a collision plate for colliding with the injected fuel.
According to the air-fuel mixture generating device of the present invention as constructed above, the fuel that is injected from the fuel injection device is forced to flow rod-like and to collide with a reflecting surface of the collision plate disposed in the air-intake passageway of the intake system, thereby enabling the fuel to be atomized and scattered as it is reflected from the reflecting surface. As a result, the atomization of fuel is promoted, so that most of the fuel injected from the fuel injection valve is permitted to diffuse into and be mixed with the air flowing through the air-intake passageway without being adhered onto the sidewall of the air-intake passageway. Therefore, it is now possible to uniformly mix the fuel and air, thereby enabling the combustibility of the air-fuel mixture to be enhanced in the internal combustion engine and hence improve the engine performance.
In yet another embodiment of the present invention, an air-cooled two-stroke gasoline engine of the crankcase precompression type having an air-intake passageway with a throttle valve having a downstream side disposed in the air-intake passageway, the air-intake passageway including a throat portion provided in a main body of an air-fuel mixture-generating device downstream of the throttle valve, wherein the improvement includes a fuel injection valve having a collision plate and a fuel injection port, the fuel injection valve being arranged at the throat portion provided on the downstream side of the throttle valve, the injecting direction of fuel from the injection port being orthogonal to a direction of the air flowing through the air-intake passageway.
As previously described, according to the fuel injection device of the present invention, since it is possible to effectively enhance the atomization of fuel being injected by the fuel injection valve without increasing the fuel supply pressure, or decreasing the pore diameter of the injection port of the fuel injection valve, the fuel injection device of the present invention is quite suited for being integrated, as fuel injection means, into an air-fuel mixture generating device wherein fuel is designed to be fed, under an enhanced pressure, to the fuel injection valve by means of a diaphragm-type fuel pump which is designed to be driven via the pressure changes (pulsating pressure) inside the crankcase of the internal combustion engine.
In accordance with the invention, the objects as described above have been met and the need in the art for a fuel-injection device and an air-fuel mixture generating device capable of effectively enhancing fuel atomization as the fuel is injected without increasing the fuel supply pressure or decreasing a pore diameter of an injection port of the fuel injection device, has been satisfied.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG. 1
is a longitudinal sectional view illustrating one embodiment of the air-fuel mixture generating device provided with a fuel injection device representing one embodiment of the present invention together with an internal combustion engine;
FIG. 2
is an enlarged cross-sectional view taken along the line II—II of
FIG. 1
;
FIG. 3
is a cross-sectional view taken along the line III—III of
FIG. 2
;
FIG. 4
is an enlarged cross-sectional view of the fuel injection valve shown in
FIGS. 1
to
3
;
FIG. 5
is a partially cut enlarged perspective view illustrating in detail the collision plate of the fuel injection valve shown in
FIGS. 1
to
4
; and
FIG. 6
is a partially cut enlarged perspective view illustrating in detail one modified example of the collision plate of the fuel injection valve shown in
FIGS. 1
to
4
.
DETAILED DESCRIPTION OF THE INVENTION
Specific embodiments of the air-fuel mixture generating device and the fuel injection device according to the present invention will be explained with reference to the drawings.
FIG. 1
shows a longitudinal sectional view illustrating one embodiment of the air-fuel mixture generating device provided with a fuel injection device representing one embodiment of the present invention together with an internal combustion engine; and
FIG. 2
shows an enlarged cross-sectional view taken along the line II—II of FIG.
1
.
Referring to
FIG. 1
, the internal combustion engine
50
is formed of a small air-cooled two-stroke gasoline engine of the crankcase precompression type which is adapted to be mounted on a portable working machine, such as a brush cutter, etc. This internal combustion engine
50
comprises a cylinder
52
in which a piston
54
is slidably fitted enabling the piston
54
to be moved in the elevational direction, and a crankcase
55
connected with the lower end of the cylinder
52
and having a crank chamber
56
therein. The cylinder
52
is provided, on the outer circumferential wall thereof, with a large number of cooling fins
58
and also with an ignition plug
59
which is positioned at the top portion of the combustion actuating chamber
53
(combustion chamber
53
a
) located over the piston
54
.
The crank chamber
56
has a short cylindrical shape and is hermetically closed. A crank shaft
60
is axially supported by the central portions of the right and left sidewalls of the crank chamber
56
. The piston
54
is connected via a connecting rod
72
with a crank pin
71
of the crank shaft
60
. A pair of crank webs
74
is fixed at the right and left ends of the crank pin
71
in such a manner that the connecting rod
72
is interposed between the pair of crank webs
74
.
The cylinder
52
is provided, at an inner wall portion thereof, with an exhaust gas port
62
which is directed so as to orthogonally intersect with the longitudinal direction of the crank shaft
60
, and at another inner wall portion thereof, with a suction port
63
which is located lower than and facing the exhaust gas port
62
(i.e. dislocated by an angle of 180 degrees). Furthermore, a pair of scavenging ports
65
forming a so-called Schnüirle type scavenging system is formed at the inner wall portions of the cylinder
52
, which are located respectively at an intermediate portion between the exhaust gas port
62
and the suction port
63
, i.e., both scavenging ports
65
facing each other and being spaced apart at an angle of 90 degrees from the exhaust gas port
62
, as well as from the suction port
63
. The scavenging ports
65
are respectively extended down to the lower portion of the cylinder
52
so as to be communicated with the top end (the downstream end) of the scavenging passageway
64
which is communicated with the crank chamber
56
.
To one side of the cylinder
52
, where the suction port
63
is located, there is attached, via a heat insulator
67
, an intake system
5
forming an intake passageway
13
, which is incorporated with the air-fuel mixture-generating device
10
according to one embodiment of the present invention and also with an air cleaner
6
. To the other side of the cylinder
52
, where the exhaust gas port
62
is located, there is attached a muffler
69
equipped with an exhaust gas purifying mechanism.
The intake passageway
13
includes a venturi passageway
13
A passing through a portion of the air-fuel mixture-generating device
10
, and a passageway
13
B passing through a portion of the heat insulator
67
. An automatic idling position reset type throttle valve
18
is disposed at the upstream side of the venturi passageway
13
A formed in the air-fuel mixture-generating device
10
.
The air-fuel mixture generating device
10
has a main body
12
, which is similar in appearance to the conventional diaphragm-type carburetor and is equipped with a diaphragm-type fuel pump
14
, which is designed to receive fuel F from a fuel tank
81
furnished with a breather
82
, and to inject the fuel F into a fuel passageway
25
(
26
-
29
) in conformity with pressure changes (pulsating pressure) inside the crank chamber
56
of the internal combustion engine
50
.
The air-fuel mixture generating device
10
also has a fuel injection valve
30
(which constitutes, as described below, a main portion of the fuel injection device
3
representing one embodiment of the present invention) for injecting, at predetermined times, the fuel F that has been introduced into the fuel passageway
25
and compressed to a predetermined magnitude, into the air-intake passageway
13
(the venturi passageway
13
A) located on the downstream side of the throttle valve
18
. The fuel injection valve
30
is disposed just over the venturi portion (throat portion)
13
a
of the venturi passageway
13
A of the main body
12
. A manual fuel pump
40
for filling the fuel passageway
25
with the fuel F at the time when the diaphragm-type fuel pump
14
is not actuated is disposed at a lower portion of the main body
12
.
The diaphragm-type fuel pump
14
includes a diaphragm
15
disposed inside the main body
12
and made of a laminate which includes a synthetic sheet and a rubber layer, and a pulsating pressure chamber
21
which is formed over the top surface of the diaphragm
15
and to which the pulsating pressure of the crank chamber
56
is designed to be transmitted via a pulsating pressure passageway
20
(including a pipe
20
A shown in
FIG. 1
) placed horizontally inside the main body
12
, and a pulsating pressure pump chamber
22
which is formed below the rear surface of the diaphragm
15
and designed to receive fuel F from the fuel tank
81
through a fuel intake passageway
24
and to inject the fuel F into the fuel passageway
25
.
There are further provided a flap valve
16
functioning as an intake valve which is formed at a portion of the diaphragm
15
located between the pulsating pressure pump chamber
22
and the fuel intake passageway portion
24
, and a flap valve
17
functioning as an injection valve which is formed at a portion of the diaphragm
15
located between the pulsating pressure pump chamber
22
and the fuel passageway
25
, both flap valves
16
and
17
being formed by respectively cutting a portion of the diaphragm
15
into a U-shape.
As clearly seen from
FIGS. 3 and 4
in addition to
FIG. 2
, the fuel injection valve
30
(which constitutes a main portion of the fuel injection device
3
representing one embodiment of the present invention) is of electromagnetic driving type and includes a cylindrical housing
31
, a field coil
32
, a stator (suction element)
33
, a plunger (valve body)
37
having a conically shaped distal end (a lower end portion) and a couple of diametrically enlarged step portions
39
each having a longitudinal groove
39
a
, a valve seat
35
having an injection port
36
to be opened and closed by means of the plunger
37
, and a compression coil spring
38
interposed between the stator
33
and the plunger
37
. The injection port
36
is opened to the throat portion
13
a
of the venturi passageway
13
A of the air-intake passageway
13
, which is located on the downstream side of the throttle valve
18
.
The fuel injection valve
30
is mounted perpendicularly to the air-intake passageway
13
, so that the direction of fuel injection from the injection port
36
is orthogonally intersected with the direction of the air flowing through the air-intake passageway.
According to this embodiment, the collision plate
90
for enabling the fuel that has been injected from the fuel injection valve
30
to collide against it is disposed midway in the air-intake passageway
13
.
As clearly seen from
FIG. 5
in addition to
FIGS. 3 and 4
, the collision plate
90
is formed integrally with the valve seat
35
and has a generally reverse-L-shaped configuration consisting of a vertically elongated portion
91
which is extended from the valve seat
35
toward the intake passageway
13
, and a horizontally elongated portion
92
which is horizontally protruded from a lower portion of the vertically elongated portion
91
and extended along the direction of the air “A” flowing through the air-intake passageway
13
, wherein the upper surface of the horizontally elongated portion
92
is constituted by a flat reflecting surface
93
which is inclined in such a manner that the portion thereof located closer to the downstream side of the air-intake passageway
13
is lowered. This reflecting surface
93
is located at a portion which is displaced away from the injection port
36
toward the downstream side thereof by a distance of about ⅕ of the diameter of the air-intake passageway
13
, and is inclined by an angle of 45 degrees relative to the air-intake passageway
13
(the direction of air flow “A” passing therethrough).
According to this fuel injection valve
30
, a pulse signal having a specific pulse width (duty ratio) corresponding to the operating conditions of the internal combustion engine
50
such as rotational speed, load, vibration, temperature, etc. is transmitted, with a predetermined timing (for example, at the moment of initiating the suction stroke), to the field coil
32
through an electronic controlling device
80
constituted by various kinds of sensor, microprocessors, etc. As a result, the field coil
32
is electrically magnetized to thereby pull up the plunger
37
against the urging force of the coil spring
38
for a period of time corresponding to the width of pulse (a time period of the electrical magnetization), thereby allowing the injection port
36
to open so as to adjust the quantity of fuel injection. It is also possible to adjust the quantity of fuel injection by feeding a predetermined number of pulses of constant breadth and at predetermined intervals on the occasion of suction strokes in conformity with the operating state of the internal combustion engine
50
.
The fuel passageway
25
includes a first passageway
26
communicated via the flap valve
17
with the pulsating pressure pump chamber
22
, an annular reserve well
28
formed around the valve seat
35
of the fuel injection valve
30
and communicated via a first communicating passage
26
a
with the first passageway
26
and via an injection valve side passage
29
and the plunger
37
with the injection port
36
, a second passageway
27
communicated via a second communicating passage
27
a
with the reserve well
28
, and a pump side passage
27
b
enabling the second passageway
27
to communicate via a pressure-adjusting valve (suction valve)
44
(to be explained hereinafter) with a manual pump chamber
40
A of the manual fuel pump
40
.
The manual fuel pump
40
is disposed because fuel is required to be manually introduced into the fuel passageway
25
at the time when the diaphragm type fuel pump
14
is not actuated, i.e. before the internal combustion is started. This manual fuel pump
40
is formed of an elastic ball made of an elastic material such as rubber and provided therein with the manual pump chamber
40
A of semi-spherical configuration, a suction port
42
equipped with the above-mentioned pressure-adjusting valve
44
, and an escape port
41
equipped with a release (escape) valve
43
. The manual pump chamber
40
A can be easily depressed as it is compressed with one's fingers and then, can be restored, by its own elastic force, to the original semi-spherical configuration as it is released.
The pressure-adjusting valve
44
disposed at the suction port
42
includes a disk-like valve body
47
for closing or opening the upper opening
42
a
of the suction port
42
, and a compression coil spring
48
for urging the valve body
47
to close the upper opening
42
a
(upward direction). This pressure-adjusting valve
44
is designed such that it is capable of acting not only as a check valve (an intake valve) when the manual fuel pump
40
is actuated but also as a relief valve for allowing the fuel F inside the fuel passageway
25
to escape into the manual pump chamber
40
A when the pressure of fuel F inside the fuel passageway
25
is increased so as to exceed a predetermined value.
The escape valve
43
disposed at the escape port
41
includes a disk-like valve body
45
for closing or opening the lower opening
41
a
of the escape port
41
, and a compression coil spring
46
for urging the valve body
45
to close the lower opening
41
a
(downward direction). This escape valve
43
is designed such that it closes the lower opening
41
a
when the pressure inside the manual pump chamber
40
A is less than a predetermined magnitude, and opens the lower opening
41
a
when the pressure inside the manual pump chamber
40
A becomes higher than this predetermined magnitude to thereby allow the air and fuel F existing in the manual pump chamber
40
A to escape via an escape passage
49
into the fuel tank
81
.
The air-fuel mixture-generating device
10
constructed in this manner can be operated in the following manner. Before the diaphragm-type fuel pump
14
is actuated (i.e. before the internal combustion engine
50
is started), the pumping operation of the device
10
, i.e., an operation wherein the manual pump chamber
40
A of the manual fuel pump
40
is forced to depress by one's fingers and then, allowed to restore the original configuration thereof by releasing this pressing force is repeated several times. By this pumping operation of the device
10
, the pressure-adjusting valve
44
disposed at the suction port
42
as well as the escape valve
43
disposed at the escape port
41
are enabled to function as a suction valve and an injection valve, respectively, thus achieving the pumping function of the device
10
.
More specifically, when the manual pump chamber
40
A is depressed, the inner volume of the manual pump chamber
40
A is compressed, thereby enabling the pressure-adjusting valve
44
to close the suction port
42
(the upper opening
42
a
) and at the same time, enabling the escape valve
43
to open the escape port
41
(the lower opening
41
a
). As a result, the air A and fuel F existing in the manual pump chamber
40
A are enabled to return through the escape port
41
and the escape passage
49
to the fuel tank
81
. On the other hand, when the manual pump chamber
40
A is released, it is allowed to return, by its own elastic force, to its original semi-spherical configuration, and at the same time, the escape valve
43
is actuated to close the escape port
41
(the lower opening
41
a
) and the pressure-adjusting valve
44
is actuated to open the suction port
42
(the upper opening
42
a
).
At this point, due to the suction force (negative pressure) that has been generated at the moment of the restoration of the manual pump chamber
40
A, the fuel F in the fuel tank
81
is introduced, via the fuel intake passageway
24
, the pulsating pressure pump chamber
22
and the flap valve
17
, into the fuel passageway
25
(
26
-
29
), thereby filling the fuel F into the fuel passageway
25
(
26
-
29
), as well as into the region around the plunger
37
of the fuel injection valve
30
.
When the internal combustion engine
50
is started by the manipulation of the recoil starter, etc., the fuel injection valve
30
is permitted to open with a predetermined timing (for example, at the moment of initiating the suction stroke) to thereby allow the fuel existing in the fuel passageway
25
to be injected from the injection port
36
, provided at the choking portion
13
a
located on the downstream side of the throttle valve
18
of the air-intake passageway
13
.
In this case, the fuel F that has been injected from the injection port
36
of the fuel injection valve
30
is forced to flow rod-like and to collide with the reflecting surface
93
of the collision plate
90
disposed midway in the air-intake passageway
13
, thereby enabling the fuel to be atomized and scattered as it is reflected from the reflecting surface
93
. As a result, the atomization of fuel is promoted, so that most of the fuel F injected from the fuel injection valve
30
is permitted to diffuse into and be mixed with the air “A” flowing through the intake passageway
13
without being adhered onto the sidewall of the air-intake passageway
13
. As a result, the fuel F and the air “A” are enabled to be uniformly mixed. The resulting air-fuel mixture is then fed to the crank chamber
56
and to the combustion actuating chamber
53
of the internal combustion engine
50
, thus allowing the air-fuel mixture to be ignited and explosively combusted by means of the ignition plug
59
, thus achieving a self-sustaining normal rotational operation of the engine.
In the normal operation of the engine after the ignition, the pressure changes (pulsating pressure) inside the crank chamber
56
, i.e. a decrease in pressure in the ascending stroke of the piston
54
and an increase in pressure in the descending stroke of the piston
54
, are transmitted to the pulsating pressure chamber
21
of the diaphragm type fuel pump
14
, thereby reciprocatively driving the diaphragm
15
(reciprocating movement). Due to the pumping action resulting from this vertical motion of the diaphragm
15
, the fuel F is sucked into the pumping chamber
22
from the fuel tank
81
, and then, fed from the pulsating pressure pump chamber
22
to the fuel passageway
25
(
26
-
29
) so as to be compressed therein during the period of time when the injection port
36
is closed.
During the normal operation of the engine, the fuel injection valve
30
is allowed to open at predetermined times (for example, at the moment of initiating the suction stroke) and remain open for a predetermined time period (for example, 1 to 3 milliseconds), depending on the operating conditions (such as the quantity of received air) of the internal combustion engine
50
, to thereby enable the pressurized fuel F in the fuel passageway
25
to be injected from the injection port
36
.
In this case, the fuel F that has been injected from the injection port
36
of the fuel injection valve
30
is forced to flow rod-like and to collide with the reflecting surface
93
of the collision plate
90
, disposed midway in the air-intake passageway
13
, thereby enabling the fuel to be atomized and scattered as it is reflected from the reflecting surface
93
. As a result, the atomization of fuel is promoted, so that most of the fuel F injected from the fuel injection valve
30
is permitted to diffuse into and be mixed with the air “A” flowing through the air-intake passageway
13
without being adhered onto the sidewall of the air-intake passageway
13
. As a result, the fuel F and the air “A” are enabled to be uniformly mixed, thereby enabling the combustibility of the air-fuel mixture to be enhanced in the engine
50
and thus improve the engine performance.
In this case, when the internal combustion engine
50
is placed into a state of high rotational speed, the quantity of fuel injected from the diaphragm-type fuel pump
14
is increased and hence the pressure of fuel F existing inside the fuel passageway
25
is also increased. However, when the pressure of fuel F existing inside the fuel passageway
25
is increased more than a predetermined value (for example, 0.05 MPa), the upper opening
42
a
is allowed to open by the pressure-adjusting valve
44
which is disposed at the intake port
42
of the manual fuel pump
40
, thereby allowing the fuel F existing inside the fuel passageway
25
to escape into the manual pump chamber
40
A of the manual fuel pump
40
. Subsequently, when the pressure inside the manual pump chamber
40
A becomes higher than a predetermined value, the lower opening
41
a
is allowed to open by the escape valve
43
which is disposed at the escape port
41
of the manual fuel pump
40
, thereby allowing the fuel F existing inside the manual pump chamber
40
A to return to the fuel tank
81
.
It is possible in this manner to inhibit the pressure (maximum pressure) of fuel F existing inside the fuel passageway
25
from exceeding the aforementioned predetermined value. As a result, it is possible to prevent the occurrence of such a situation where the fuel F is excessively injected from the fuel injection valve
30
to thereby feed an excessively concentrated air-fuel mixture to the combustion actuating chamber
53
of the internal combustion engine
50
.
As explained above, according to the fuel injection device
3
of this embodiment, the fuel F that has been injected from the injection port
36
of the fuel injection valve
30
is forced to flow rod-like and to collide with the reflecting surface
93
of the collision plate
90
disposed midway in the air-intake passageway
13
, thereby enabling the fuel to be atomized and scattered as it is reflected from the reflecting surface
93
. As a result, the atomization of fuel is promoted, so that most of the fuel F injected from the fuel injection valve
30
is permitted to diffuse into and be mixed with the air “A” flowing through the air-intake passageway
13
without being adhered onto the sidewall of the air-intake passageway
13
. As a result, the fuel F and the air “A” are enabled to be uniformly mixed, thereby enabling the combustibility of the air-fuel mixture to be enhanced in the engine
50
and thus improve the engine performance.
As explained above, according to the fuel injection device
3
of this embodiment, since it is possible to effectively enhance the atomization of fuel on the occasion of injecting it from the fuel injection valve without increasing the fuel supply pressure fed to the fuel injection valve, or decreasing the pore diameter of the injection port of the fuel injection valve, the fuel injection device is quite suited for being integrated, as fuel injection means, into the air-fuel mixture-generating device
10
of the aforementioned structure wherein fuel is designed to be fed, under an enhanced pressure, to the fuel injection valve by means of a diaphragm-type fuel pump, which is designed to be driven by the pressure changes (pulsating pressure) inside the crankcase of the internal combustion engine.
Although the invention has been described herein by reference to specific embodiments thereof, it will be understood that such embodiments are susceptible of modification and variation without departing from the inventive concepts disclosed.
For example, the reflecting surface
93
of the collision plate
90
may be modified in such a manner as shown in FIG.
6
. Referring to
FIG. 6
, the reflecting surface
93
includes a U-shaped groove
95
, which is semi-circular in cross-section, as a restricting means in the reflecting surface
93
for restricting the direction of reflection and diffusion of the fuel F that collides with the reflecting surface
93
, directed in line with the direction of the air “A” flowing through the air-intake passageway
13
as well as in line with a direction intersecting orthogonally with the fuel injecting direction of the fuel injection valve
30
.
As clear from the above explanation, in the air-fuel mixture generating device of the present invention, since the fuel that has been injected from the fuel injection valve is forced to flow rod-like and to collide against the reflecting surface of the collision plate which is disposed midway in the air-intake passageway, it is possible to enable the fuel to be effectively atomized and scattered as it is reflected from the reflecting surface. As a result, the atomization of fuel is promoted, so that most of the fuel injected from the fuel injection valve are permitted to diffuse into and be mixed with the air flowing through the air-intake passageway without being adhered onto the sidewall of the air-intake passageway. Therefore, it is now possible to uniformly mix the fuel and air, thereby enabling the combustibility of the air-fuel mixture to be enhanced in the internal combustion engine and thus improve the engine performance.
Furthermore, according to the fuel injection device of the present invention, since it is possible to effectively enhance the atomization of fuel as it is injected from the fuel injection valve without increasing the fuel supply pressure fed to the fuel injection valve, or decreasing the pore diameter of the injection port of the fuel injection valve, the fuel injection device of the present invention is quite suited for being integrated, as fuel injection means, into an air-fuel mixture-generating device wherein fuel is designed to be fed, under an enhanced pressure, to the fuel injection valve by means of a diaphragm-type fuel pump which is designed to be driven via the pressure changes (pulsating pressure) inside the crankcase of the internal combustion engine.
All such modifications, therefore, are intended to be included within the spirit and scope of the appended claims.
Claims
- 1. An air-fuel mixture generating device, comprising:(a) a main body; (b) a diaphragm fuel pump disposed in said main body; (c) a fuel passageway in the main body operationally coupled to said fuel pump for receiving and pressurizing fuel injected from the fuel pump in conformity with pressure changes inside a crankcase of an internal combustion engine; (d) a fuel injection device mounted on said main body and operationally coupled to said fuel passageway for receiving the pressurized fuel therefrom and injecting said pressurized fuel into an air-intake passageway of an intake system of the internal combustion engine; and (e) said fuel injection device comprising a collision plate for colliding with the injected fuel.
- 2. The air-fuel mixture generating device of claim 1, wherein said fuel injection device comprises an electromagnetic driving-fuel injection valve for injecting fuel into the air-intake passageway of the intake system at predetermined times.
- 3. The air-fuel mixture generating device of claim 2, wherein said collision plate comprises a reflecting surface for enabling the injected fuel to be atomized and scattered in the air-intake passageway.
- 4. The air-fuel mixture generating device of claim 3, wherein said reflecting surface is inclined so as to enable the collided fuel to reflect therefrom and diffuse along a direction of air flowing trough the air-intake passageway of the intake system.
- 5. The air-fuel mixture generating device of claim 4, wherein said reflecting surface comprises restricting means for restricting a direction of reflection and diffusion of the collided fuel, said restricting means being directed in line with a direction of the air flowing through the air-intake passageway as well as in line with a direction intersecting orthogonally with a fuel-injecting direction of said fuel injection valve.
- 6. The air-fuel mixture generating device of claim 5, wherein said restricting means is a U-shaped groove formed in said reflecting surface.
- 7. An air cooled two-stroke gasoline engine of the crankcase precompression having an air-intake passageway and a throttle valve having a downstream side disposed in the air-intake passageway, the air-intake passageway including a throat portion provided in a main body of an air-fuel mixture generating device downstream of the throttle valve, wherein the improvement comprises a fuel injection valve having a collision plate and a fuel injection port, the fuel injection valve being arranged at the throat portion provided on the downstream side of the throttle valve, the injecting direction of fuel from said injection port being orthogonal to a direction of the air flowing through the air-intake passageway.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2001-115829 |
Apr 2001 |
JP |
|
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
4105004 |
Asai et al. |
Aug 1978 |
A |
5586524 |
Nonaka et al. |
Dec 1996 |
A |
5725158 |
Klaski et al. |
Mar 1998 |
A |
6508232 |
Sogawa |
Jan 2003 |
B2 |
Foreign Referenced Citations (3)
Number |
Date |
Country |
4629576 |
Aug 1971 |
JP |
4635455 |
Dec 1971 |
JP |
482483 |
Jan 1973 |
JP |