JP2738837B2 - Starter increase device for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starting and increasing device for an internal combustion engine, and more particularly to a device for increasing the amount of fuel and air when the engine temperature is low, such as during starting. .

2. Description of the Related Art Conventionally, as this type of internal combustion engine start increasing device, there is a device that uses a negative pressure in an intake manifold to supply an increased amount of fuel and air to the internal combustion engine in a mixed state. However, in this case, when a large amount of fuel is required at the time of starting, this cannot be satisfied, and when the throttle valve is fully opened, an increased amount of fuel cannot be supplied.

Further, in the related art, there is a type in which only the fuel is increased using a pressure pump. In this case, although a large amount of fuel can be supplied at the start, the air-fuel ratio of the fuel supplied to the engine after the start becomes too rich, and it is difficult to maintain the engine rotation. Further, in this case, even if the air is mixed with the fuel, there is a problem that the fuel flows backward in the passage for sending the air.

[Problems to be Solved by the Invention] The present invention has been made in view of such problems of the prior art, and an object thereof is to supply fuel and air at an appropriate air-fuel ratio in an increased amount, An object of the present invention is to provide an internal combustion engine start increasing device which facilitates start and stabilizes engine rotation after start.

Means for Solving the Problems In order to achieve such an object, the present invention includes a plurality of cylinders arranged vertically and a crankshaft bearing provided between the cylinders. A starting fuel increase device applied to a two-stroke engine in which an intake passage communicates with a case, the fuel increasing device having a pumping means, and supplying a fuel increase to an engine body via a fuel increase passage; And a valve for opening the fuel increase passage when the engine temperature is equal to or lower than a predetermined temperature, and a main air passage of the engine main body are arranged independently to supply air to the engine main body in synchronization with the supply of the increased fuel. A supplementary air passage, and only the intake passages of some of the plurality of cylinders, including the uppermost cylinder, are supplied with increased fuel through the supplemental fuel passage and air through the supplementary air passage. It is composed.

[Operation] With this configuration, the increased fuel is supplied to the uppermost cylinder of the engine body by using the pumping means by the fuel increasing device, and the supply of the increased fuel is operated by a valve that opens when the engine temperature is below a certain temperature. I do. In synchronization with the supply of the increased amount of fuel, air is further supplied to the engine main body from the auxiliary air passage. Further, a part of the fuel supplied to the uppermost cylinder and entering the crankcase is supplied to the lower cylinder through the crankshaft bearing portion.

EXAMPLES The present invention will be described below based on examples shown in the drawings.

FIG. 1 shows an embodiment of a marine engine as an internal combustion engine. Here, an engine 10 having three cylinders and two cycles is shown. The engine 10 is mounted on an upper casing 12 via an exhaust guide 14, and is covered by a bottom cowling 16 and a top cowling 18. 20 is flywheel magneto, 22 is its cover, 24
Is a spark plug. The upper casing 12 is attached to the stern plate 30 of the hull via a swivel bracket 26 and a clamp bracket 28, and tilts up and down by pivoting the swivel bracket 26 around the tilt axis 29 with respect to the clamp bracket 28. It is possible. In addition, the steering bracket 32 can swing left and right through the swivel bracket 26 by operation.

As shown in FIG. 2, the engine 10 is a vertically mounted crankshaft.
The crankshaft 34 is connected to the piston 36 of each cylinder via a connecting rod 38. Crank chamber 40
Is an intake manifold equipped with a reed valve 42 for each cylinder
The intake silencers 46 are arranged upstream of the carburetors 44 and communicate with the carburetors 44 via 43. 47 is a main air passage, 48 is a throttle valve, 49 is a float chamber, 50 is a main nozzle, 51 is a slow boat, 52 is a carburetor support plate, 53
Is a connecting shaft for opening and closing the throttle valve 48 in conjunction with
54 is a cylinder body, 55 is a cylinder head, 56 is a scavenging passage, and 57 is a fuel chamber.

Referring also to FIG. 3, the intake manifold 43 is formed with balance passages 60, 61, and 62 for communicating the intake passages 58 penetrating through the carburetor support plate 52 for the respective cylinders. These balance passages function as communication passages for equalizing and increasing the boost pressure of each intake passage 58.

Reference numeral 63 denotes a fuel intensifier. The fuel intensifier 53 has a pump chamber 65 provided with a diaphragm 64. The pump chamber 65 is connected to an outlet passage 67 of the float chamber 49 via a suction valve 66. Reference numeral 68 denotes a throttle portion at the entrance of the outlet passage 67 of the float chamber 49, reference numeral 69 denotes a fuel reservoir for maintaining the start of which the upper part communicates with the upper part of the float chamber 49, reference numeral 70 denotes a float, and reference numeral 71 denotes a communication path to the crank chamber. This is the same as the communication path 71 in the extender 63.
The fuel pressurized by the diaphragm 64 which operates in response to the pulse of the crank chamber is discharged from the pump chamber 65 via the discharge valve 72 and reaches the valve body 74 at the lower end of the valve shaft 73 constituting the on-off valve. The valve shaft 73 is urged downward by a spring 75 in a direction in which the valve body 74 is closed, and is housed in the bobbin 76 so as to be vertically movable. A solenoid coil 77 is arranged on the outer periphery of the bobbin 76. The solenoid coil 77 is energized in response to an engine temperature signal from a temperature sensor (not shown), and opens and closes the valve body 74.

The state shown in FIG. 3 is a state in which the valve element 74 is closed. However, when the engine temperature falls below a certain temperature, the coil 77 is excited and the valve shaft 73 moves up together with the valve element 74, as shown in FIG. The on-off valve opens as described above, and the pressurized fuel is supplied from the outlet 78 to the intake passage 58 of the intake manifold 43 via the fuel-enhancing passage 79.

80 is a manual valve for manually opening and closing the valve body 74,
The valve stem 82 is moved up and down by manual operation of the starter knob 81,
The valve element 83 at the tip is opened and closed, whereby the valve element 74 is opened.
And can supply increased fuel.

The on-off valve in the fuel intensifier 63 also functions as an on-off valve for the auxiliary air passage. That is, a conduction path 85 through which air is introduced from the air throttle unit 84 is provided in the fuel extender 63 main body, and the conduction path 85 is opened and closed by being moved up and down by a through hole 86 formed in the valve shaft 73. It has become. In the state of FIG. 3, air is not conducted because the through hole 86 is displaced with respect to the conduction path 85, but when the engine temperature is lower than a certain value, the valve shaft
Simultaneously with the rise of 73, the through hole 86 communicates with the conduction path 85, and as shown in FIG.
The air is supplied to the carburetor 44a of the first cylinder and the carburetor 44c of the third cylinder through the auxiliary air passage 86 to the portion where the intake negative pressure acts downstream of the throttle valve 48.

According to the first embodiment, an air-fuel mixture having a higher fuel ratio than the air-fuel ratio of the air from the main air passage 47 and the fuel from the main nozzle 50 can be supplied. That is, the increased fuel for the start is supplied to the cylinder by applying a pressure from the pumping means comprising the pump chamber 65 of the fuel intensifier 63 in addition to the intake negative pressure of the intake passage 58, and is supplied to the cylinder only by the intake negative pressure. A large amount of fuel can be sent at the time of starting compared to a slow system fuel passage (not shown) for supplying fuel, and the starting can be facilitated. Further, since air is introduced into the carburetor from the auxiliary air passage 88 in a separate system from that of the fuel to be increased in synchronization with the opening and closing valve of the fuel intensifier 63 being opened, an appropriate air-fuel ratio is used for starting and continuing rotation. The supplied fuel can be supplied to the cylinder to stabilize the engine rotation after starting. This is more remarkable when the throttle valve 48 is closed and the supply of the air-fuel mixture by the air in the main air passage 47 and the fuel only by the main nozzle 50 and other intake negative pressure alone is stopped. Here, the air from the sub air passage is guided to a portion of the cylinder where the intake negative pressure acts, so that the fuel is also prevented from flowing back through the sub air passage. In this embodiment, the increased fuel and the air are sent to a plurality of cylinders, but these may be sent to at least one cylinder.

FIGS. 5A and 5B show a second embodiment of the present invention. This embodiment is different from the first embodiment in that the opening and closing of an open / close valve by a solenoid coil of a fuel extender 63 is changed.
This is the point that this valve was opened and closed using a wax 90. The heater 89 is heated by electricity generated by a power generation coil (not shown) provided in the flywheel magneto 20. As shown in FIG. 5A, since the heater 89 at the time of starting does not sufficiently heat the wax 90, the wax 90 is contracted, and the needle valve 92 is opened while compressing the spring 91. At the same time, the air passage 85 is also communicated with the through hole 86, and the air is supplied to the vaporizer. With the warm-up, the heater 89 continues to heat the wax, so that the wax 90 extends as shown in FIG.
Close the 92 and the auxiliary air passage. After the engine is stopped, no electric power is supplied to the heater 89, so that the temperature of the wax 90 decreases in step with the decrease in the engine temperature. By inflating the tip of the needle valve 92, the closing ratio of the needle valve 92 can be increased as compared with closing the auxiliary air passage as the engine warms up, and the air-fuel ratio can be gradually changed to a thinner value.

6A and 6B show a third embodiment of the present invention. This embodiment is different from the first embodiment in that a valve shaft 73 of a fuel intensifier 63 is provided.
Is that it can be operated manually. In particular,
The valve shaft 73 is arranged horizontally, and a manual knob 93 is provided from its proximal end.
The manual knob 93 allows the passage of the increased fuel and the passage of the auxiliary air to be simultaneously opened and closed.
In this embodiment, the manual valve 80 shown in the first embodiment becomes unnecessary.

FIG. 7 shows a fourth embodiment of the present invention. This embodiment is different from the first embodiment in that the auxiliary air passage 88 is provided in the carburetor support plate 52 of the intake manifold 43 (see FIG. 2). This is the point where it has joined with the increased fuel. Also in this embodiment, the increased amount of fuel is reduced by the fact that the intake negative pressure is acting on the intake passage 58 and the discharge pressure of the fuel is reduced at the point when the fuel reaches the confluence because it is far from the pumping means. There is no backflow in the sub air passage 88.

FIG. 8 shows a fifth embodiment of the present invention. This embodiment is different from the first embodiment in that the auxiliary air passage 88 is connected to the fuel increasing passage 79.
Is connected in the middle of the process, and the air merges with the increased amount of fuel and is supplied to the intake manifold. Where 94 is the secondary air passage
While receiving the air from 88 and merging with the increased fuel,
This is a fluid coupling that forms a maze so as to prevent the fuel from flowing back to the auxiliary air passage 88 as much as possible, and that sucks air by the flow rate of the increased fuel, and that the upstream inner cylinder 95 of the fuel is deep inside the downstream outer cylinder 96. It has a structure to be inserted.

Next, FIG. 9 shows a sixth embodiment of the present invention. This embodiment is different from the fifth embodiment in that the valve structure for the auxiliary air passage is eliminated, and The fluid coupling 94 is integrally attached to connect a short auxiliary air passage 88 to the fluid coupling 94, and a check valve 97 is provided in the auxiliary air passage 88. According to this embodiment, as compared with the fifth embodiment, the backflow of the fuel can be more reliably prevented, and the air can be supplied in synchronization with the flow rate, that is, the supply of the increased fuel. .

[Effects] As described above, according to the present invention, a large amount of fuel can be sent at the time of starting, so that starting is facilitated, and after starting, a fuel having an appropriate air-fuel ratio by supplying air is provided. However, there is an effect that the stability of the engine rotation is secured and the sustainability after starting is improved. In addition, since increased fuel is supplied to at least the top cylinder, a part of the fuel entering the crankcase descends down through the crankshaft bearing part, so that the top cylinder outputs power. And the fuel in the lower cylinder is appropriately increased even when the lower cylinder is cold, so that stable combustion can be maintained. Further, there is an effect that the structure can be simplified if at least one fuel increase passage is provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main part of an outboard motor to which the present invention is applied, FIG. 2 is a cross-sectional view showing the entire first embodiment of the present invention,
FIG. 3 is an exploded sectional view showing the fuel increasing device in the embodiment in detail, FIG. 4 is a schematic diagram showing an operation state of the on-off valve in the embodiment, and FIG. 5A is a valve showing a second embodiment of the present invention. FIG. 5B is a schematic view showing a closed state of the valve in the embodiment, FIG. 6A is a cross-sectional view of a main part of the third embodiment of the present invention, and FIG. 6B is a valve of the embodiment. FIG. 7 is a schematic diagram showing a closed state, FIG. 7 is a system diagram showing a fourth embodiment of the present invention, FIG. 8 is a sectional view of a main part showing a fifth embodiment of the present invention, and FIG. It is principal part sectional drawing which shows 6th Example. 10 Engine 63 Fuel booster 65 Pump chamber 73 Valve shaft 79 Fuel-increasing passage 86 Through-hole 88 Sub-air passage

Claims (1)

(57) [Claims] The present invention relates to a starting and increasing device applied to a two-stroke engine including a plurality of cylinders arranged in a vertical direction and a crankshaft bearing provided between the cylinders, wherein an intake passage communicates with a crankcase. A fuel increasing device having a pressure feeding means for supplying an increased amount of fuel to the engine main body via the fuel increasing passage; and a fuel increasing device disposed in the fuel increasing passage, wherein the fuel increasing passage is provided when the engine temperature is equal to or lower than a predetermined temperature. An opening valve and a main air passage of the engine main body, which are disposed independently of each other, and include a sub air passage for supplying air to the engine main body in synchronization with the supply of the increased fuel, and an uppermost cylinder of the plurality of cylinders A fuel-increasing device for supplying fuel to the fuel-increasing passage and air to the sub-air passage only in the intake passages of some of the cylinders.