JPH04209932A - Supercharge four-cycle model engine - Google Patents

Abstract

PURPOSE:To supercharge an engine without separately providing a supercharger by alternately performing explosion in the first/second cylinder sides, and performing, when the one cylinder side is in an explosion stroke, the supercharge in the other cylinder side. CONSTITUTION:When a piston 6a in a side of the first cylinder 5a is advanced into a compression stroke, a piston 6b in a side of the second cylinder 5b is advanced into an exhaust stroke. Consequently, a negative pressure is generated in space 8 in a crankcase 1 to open a check valve 9, and a mixture of fuel, mixing lubricating oil, with air is sucked to the space 8 in the crankcase 1 from a carburetor 10. When the first piston 6a is transferred to an explosion stroke, the second piston 6a is transferred to a suction stroke to open an intake valve 13b. Accordingly, the space 8 is compressed to increase a pressure of the space 8 by closing the check valve 9. Consequently, the mixture, whose pressure is increased, is press-fed from the space 8 into the second cylinder 5b via a check valve 15b, intake pipe 16b and a suction port 11b to supercharge an engine.

Description

[Detailed description of the invention]

[00011

[Industrial Field of Application] The present invention relates to a four-stroke model engine that performs supercharging. [0002] Conventionally, when supercharging an engine, it has been necessary to provide a supercharger in addition to the engine. [0003] Additionally, in model engines, generally,
Fuel mixed with lubricating oil is used, and the lubricating oil enters the combustion chamber of the engine along with the fuel, enters the crankcase from the combustion chamber through the gap between the cylinder and piston, and lubricates the inside of the crankcase. I was trying to do this. [0004]

[Problems to be Solved by the Invention] Conventionally, when supercharging an engine, a supercharger is required in addition to the engine as described above, which increases the total weight and increases the cost. There was a problem. [0005] Furthermore, in conventional model engines, as mentioned above, lubricating oil enters the crankcase through the gap between the cylinder and the piston, so the gap between the cylinder and the piston must be made large. This resulted in a decrease in output. [0006] The present invention has been made in view of the above circumstances, and it is possible to perform supercharging without providing a separate supercharger, and it is also possible to increase the gap between the cylinder and the piston. It is an object of the present invention to provide a model engine which is capable of increasing the output by sufficiently lubricating and cooling the inside of the crankcase. [0007]

[Means for Solving the Problems] A supercharged four-stroke model engine according to the present invention is a four-stroke model engine that uses fuel mixed with lubricating oil, in which first and second cylinders alternately undergo explosive strokes. , a mixture passage connecting a space in the crankcase and a mixture supply source such as a carburetor, and a mixture passage provided in the mixture passage and allowing only the flow of the mixture from the mixture supply source to the space; a check valve on the air-fuel mixture supply source side that does not allow reverse flow; a first suction passage connecting the space and the suction port on the first cylinder side; a first cylinder-side check valve that allows the air-fuel mixture to flow only from the space toward the first cylinder and does not allow the reverse flow; and a first cylinder-side check valve that connects the space and the second cylinder-side inlet. a second suction passage; and a second cylinder-side check valve provided in the second suction passage, which allows only the flow of the air-fuel mixture from the space to the second cylinder, and does not allow the reverse flow. It is something that we have. [0008]

[Operation] In the present invention, when the piston on the first cylinder side enters the compression stroke, the piston on the second cylinder side enters the exhaust stroke. As a result, the space inside the crankcase becomes negative pressure, the check valve on the mixture supply source side opens, and the mixture of fuel and air mixed with lubricating oil is released into the crankcase from the mixture supply source such as a carburetor. being sucked into the space of [00091] Next, when the piston on the first cylinder side moves to the explosion stroke, the piston on the second cylinder side moves to the suction stroke, and the suction valve opens. Therefore, the space inside the crankcase is compressed, the check valve on the side of the air-fuel mixture supply source closes, and the pressure in the space inside the crankcase increases, so that the air-fuel mixture with increased pressure is transferred from the space to the second cylinder side. The fuel is fed under pressure into the second cylinder via the check valve, the second suction passage, and the suction port, and supercharging is performed. [00101Next, the first cylinder side moves to the exhaust stroke and the second cylinder side moves to the compression stroke, so the space inside the crankcase becomes negative pressure in the same way as above, and the check valve on the air-fuel mixture supply source side opens and air-fuel mixture is sucked from the air-fuel mixture source into the space within the crankcase. [00111 Next, the piston on the first cylinder side moves to the suction stroke, the suction valve opens, and the piston on the second cylinder side moves to the explosion stroke. Therefore, the space inside the crankcase is compressed, the check valve on the air-fuel mixture supply side closes, and the pressure in the space inside the crankcase increases. The fuel is pumped into the first cylinder through the stop valve, the first suction passage, and the suction port to perform supercharging. [00121 From then on, by repeating the same cycle, explosions are performed alternately on the first cylinder side and the second cylinder side, and when one cylinder side is in the explosion stroke,
Supercharging is performed on the other cylinder side. Note that the first and second cylinder-side check valves respectively prevent the air-fuel mixture from flowing back into the space within the crankcase from the first and second cylinder sides. [0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on embodiments shown in the drawings. FIG. 1 shows an embodiment in which the present invention is applied to a two-cylinder four-stroke model engine. In this example,
A crankshaft 4 is connected to the crankcase 1 via bearings 2 and 3.
is rotatably supported. The crankcase 1 is integrally provided with a first cylinder 5a and a second cylinder 5b, and pistons 6a and 6b are fitted into the cylinders 5a and 5b, respectively. The piston 6
a and 6b are connected to the crankshaft 4 via connecting rods 7a and 7b, respectively. The crankcase 1 is hermetically sealed, and a space 8 within the crankcase 1 is connected to a mixture outlet of a carburetor 10 via a check valve 9 on the carburetor side and a mixture pipe 20. The check valve 9 is connected to the carburetor 1
Only the flow from 0 to space 8 is allowed, and the opposite flow is not allowed. [0014] 11a and 12a are each cylinder 5a
The intake port and exhaust port 13a and 14a provided on the sides are an intake valve and an exhaust valve that open and close the intake port 11a and the exhaust port 12a, respectively. The space 8 within the crankcase 1 is connected to the suction port 11a via a first cylinder-side check valve 15a and a first suction pipe 16a. Said check valve 1
5a only allows flow from space 8 toward cylinder 5a;
Reverse flow is not allowed. The exhaust port 12
a is connected to the exhaust pipe 17a. llb and 12b are an intake port and an exhaust port provided on the second cylinder 5b side, respectively, and 13b and 14b are an intake valve and an exhaust valve that open and close the intake port 11b and the exhaust port 12b, respectively. The space 8 inside the crankcase 1 is a second cylinder side check valve 15b.
and is connected to the suction port 11b via the second suction pipe 16b. The check valve 15b allows flow only from the space 8 toward the cylinder 5b, and does not allow flow in the opposite direction. The exhaust port 12b is connected to an exhaust pipe 17b. [0015] Next, the operation of this embodiment will be explained. [0016] When the piston 6a on the first cylinder 5a side enters the compression stroke, the piston 6b on the second cylinder 5b side
enters the exhaust stroke. Therefore, the space 8 inside the crankcase 1 becomes negative pressure, the check valve 9 opens, and the mixture of fuel and air mixed with lubricating oil is sucked into the space 8 inside the crankcase 1 from the carburetor 10. . [00171 Next, as shown in FIG. 1, when the piston 6a on the first cylinder 5a side moves to the explosion stroke,
The piston 6a on the second cylinder 5b side moves to the suction stroke, and the suction valve 13b opens. Therefore, crankcase 1
The space 8 inside the crankcase 1 is compressed, the check valve 9 is closed, and the pressure in the space 8 inside the crankcase 1 rises, so that the air-fuel mixture with increased pressure flows from the space 8 to the check valve 15b and the suction pipe 16.
b. The fuel is fed under pressure into the second cylinder 5b through the suction port 11b, and supercharging is performed. [0018] Next, the first cylinder 5a side moves to the exhaust stroke, and the second cylinder 5b side enters the compression stroke, so the space 8 in the crankcase 1 becomes negative pressure, and the check valve 9 opens. Air-fuel mixture is sucked into the space 8 within the crankcase 1 from the carburetor 10. [00191 Next, the piston 6 on the first cylinder 5a side
a moves to the suction stroke, the suction valve 13a opens, and the piston 6b on the second cylinder 5b side moves to the explosion stroke. Therefore, the space 8 inside the crankcase 1 is compressed, the check valve 9 is closed, and the pressure in the space 8 inside the crankcase 1 increases, so that the air-fuel mixture with increased pressure is released from the space 8 through the check valve 15a. The fuel is fed under pressure into the first cylinder 5a through the suction pipe 16a and the suction port 11a, and supercharging is performed. [00201 From then on, similar cycles are repeated, whereby explosions are performed alternately on the cylinder 5a side and 5b side, and when one cylinder side is in the explosion stroke, supercharging is performed on the other cylinder side. In addition, the check valves 15a and 15b
prevents the air-fuel mixture from flowing back into the space 8 in the crankcase 1 from the cylinders 5a and 5b. [00211] In this engine, the engine output can be increased by supercharging the engine itself without providing a separate supercharger. [0022] Furthermore, since the lubricating oil enters directly into the crankcase 1 together with the fuel, it is possible to sufficiently lubricate and cool the crankcase 1 at low cost. Since there is no need to infiltrate lubricating oil into the cylinders, the gaps between the cylinders 5a, 5b and the pistons 6a, 6b can be made smaller, which also makes it possible to increase the output of the engine. Although the embodiment is an example in which the present invention is applied to a two-cylinder model engine, the present invention can also be applied to a model engine with three or more cylinders. [0023]

[Effects of the Invention] As explained above, according to the present invention. (a) Supercharging can be performed without providing a separate supercharger, and cost and weight can be reduced. [0024] (b) There is no need to increase the gap between the cylinder and the piston, and the inside of the crankcase can be sufficiently lubricated and cooled, which also makes it possible to increase output. You can get the effect.

[Brief explanation of the drawing]

FIG. 1 is a simplified cross-sectional view of an embodiment of a supercharged four-stroke model engine according to the present invention.

[Explanation of symbols]

1 Crankcase 5a First cylinder 5b Second cylinder 6a Piston 6b Piston 8 Space in the crankcase 9 Carburetor (air mixture supply source) side check valve 10 Carburetor (air mixture supply source) 11a Inlet port 11b Intake Port 13a Suction valve 13b Suction valve 15a First cylinder side check valve 15b Second cylinder side check valve 16a First suction pipe 16b Second suction pipe

Claims (1)

[Claims] Claim 1: In a four-stroke model engine that uses fuel mixed with lubricating oil, first and second cylinders, which alternately undergo explosion strokes, are connected to a space within the crankcase and a mixture supply source. a mixture passage; a mixture supply source-side check valve provided in the mixture passage that allows the mixture to flow only from the mixture supply source to the space; and not to allow the mixture to flow in the opposite direction; A first suction passage connecting the suction port on the first cylinder side and a first suction passage provided in the first suction passage allow only the flow of the air-fuel mixture from the space to the first cylinder, and vice versa. a first cylinder-side check valve that does not allow flow; a second suction passage that connects the space and the second cylinder-side suction port; A supercharged four-stroke model engine comprising a second cylinder-side check valve that allows only the flow of the air-fuel mixture toward the second cylinder and does not allow the reverse flow.