JP2637311B2 - Internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine such as a four-cycle gasoline engine.

[0002]

2. Description of the Related Art A conventional four-stroke gasoline engine has a cylinder provided with an exhaust valve, an intake valve, and a spark plug in an upper part thereof, a piston reciprocating in the cylinder, and a crankshaft connected to the piston via a connecting rod. Consisting of

In this internal combustion engine, one cycle is completed by four strokes (a suction stroke, a compression stroke, an action stroke, and an exhaust stroke), and the operation of the engine is continued by repeating this cycle. In the suction stroke, as the intake valve opens and the piston moves downward from top dead center to bottom dead center, a mixture of vaporized gasoline and air is sucked into the cylinder through the valve port. It is. The piston reaches the bottom dead center and the suction stroke ends.

[0004] When the piston reaches the bottom dead center, it then begins its upward movement. At the same time, the intake valve is closed. The exhaust valve is also closed and the cylinder is sealed. As the piston rises, the mixture is compressed, and by the time the piston reaches top dead center, the mixture is compressed to less than one sixth of its original volume. As the air-fuel mixture is compressed, the pressure rises and the temperature rises (compression stroke).

[0005] At the end of the compression stroke, when the piston reaches the top dead center, an electric spark jumps at the spark plug and the air-fuel mixture is ignited. When ignited, the air-fuel mixture burns rapidly, the pressure in the cylinder increases, and the piston receives a force that is depressed. This force becomes power, and the crankshaft generates a rotational force (action stroke).

[0006] When the working stroke is completed and the piston reaches the bottom dead center, the exhaust valve opens (the intake valve is closed) and the piston starts to move upward. In the operation stroke, the combustion gas expanded by giving work to the piston is pushed out to the atmosphere through an exhaust valve port as the piston rises (exhaust stroke). Thus, when the piston reaches the top dead center, the exhaust valve closes and the process proceeds to the previous suction stroke, and the cycle is repeated.

[0007]

In the above-described four-stroke gasoline engine, only the operation stroke of the four strokes in one cycle generates power and applies a rotational force to the crankshaft. That is, when the compression stroke is completed and the piston reaches the top dead center, a downward force is applied to the piston only by the explosion of the air-fuel mixture, and no rotational force is applied to the crankshaft during the remaining three strokes.

By the way, the point at which the piston is located at the top dead center is a position on the rotational trajectory of the crankshaft where the rotational force is least transmitted and the rotational efficiency is poor. For this reason, "unevenness" occurs in the rotational force of the crankshaft, and efficient and smooth rotation cannot be obtained. This has the disadvantage of poor engine efficiency.

[0009] The present invention solves the above problems,
It is an object of the present invention to provide an internal combustion engine that has a uniform crankshaft rotational force, low fuel consumption, and high engine efficiency by obtaining two explosions with a time difference in the operation stroke during one cycle.

[0010]

In order to achieve this object, an internal combustion engine according to the present invention comprises a cylinder provided with an exhaust valve, an intake valve, and a spark plug on an upper part thereof, and a piston reciprocating in the cylinder. An internal combustion engine comprising a piston and a crankshaft connected to the piston via a connecting rod, wherein each of the pistons communicates with a first combustion chamber of the cylinder at a portion opposed to a peripheral surface of the cylinder below a top dead center of the piston. And a second combustion chamber which is opened and closed by the reciprocating motion of the piston is provided so as to protrude outward, and an exhaust valve is provided on the side of the second combustion chamber opposite to the peripheral surface side of the cylinder. The air-fuel mixture is sucked into the first and second combustion chambers, the second combustion chamber is sealed by the piston by the time the piston reaches the top dead center position during the compression stroke, and the fuel in the first combustion chamber during the operation stroke. Combustion in the second combustion chamber at the time the second combustion chamber piston is pushed down is opened, characterized in that so as to generate a.

In the internal combustion engine having such a configuration, 1
In the working stroke of the cycle, the combustion in the first combustion chamber is followed by the combustion in the second combustion chamber, that is, two explosions occur in one cycle, so that the rotational force of the crankshaft increases. Not only does the output increase, but also there is no unevenness in the rotational force of the crankshaft.

To explain this, when the piston descends during the suction stroke, the air-fuel mixture is sucked into the cylinder. However, since the first and second combustion chambers are present, the air-fuel mixture is compared with the case where only the first combustion chamber is provided. Therefore, since the volume is substantially increased (the exhaust amount is increased), the amount of the air-fuel mixture sucked in one cycle is increased accordingly. Therefore, the air-fuel mixture is not dispersed to the first and second combustion chambers,
The concentration of the air-fuel mixture in the first and second combustion chambers is the same as in the case of only the first combustion chamber, and even if the second combustion chamber is opened following combustion in the first combustion chamber ( Even if the internal volume increases),
The explosive power does not decrease, and the output is increased by performing the combustion in the second combustion chamber.

Also, since the explosive power does not fall, the first
By performing the combustion in the second combustion chamber subsequent to the combustion in the combustion chamber, the state in which the rotational force of the crankshaft is large for a long time continues and the unevenness in the rotational force of the crankshaft is reduced. On the other hand, in the case of only the first combustion chamber, there is no way to apply a rotational force to the crankshaft after the end of one combustion until the next combustion, and the rotational force is decreasing only (by inertia). Just rely on it). However, if the second combustion is performed after a considerable time has elapsed since the end of the first combustion, the rotational force of the crankshaft may be uneven,
Such does not occur because there is little time difference between the first combustion and the second combustion.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an internal combustion engine according to the present invention will be described based on embodiments. FIG. 1 is a sectional view of a main part showing a specific embodiment of an internal combustion engine according to the present invention, and FIG. 2 is a plan sectional view thereof.

The internal combustion engine shown in this embodiment is a four-cycle gasoline engine. This internal combustion engine, as is well known, includes a cylinder 1 provided with an exhaust valve 11, an intake valve 12, and a spark plug 13 at an upper part, and a piston (a piston ring 21 for maintaining airtightness) reciprocatingly sliding in the cylinder 1. A piston (fitted piston) 2 and a crankshaft (crank pin 41, crankshaft 42) 4 connected to the piston 2 via a connecting rod 3. Although not shown, the internal combustion engine includes a carburetor for producing a mixture of fuel and air to be supplied to the cylinder 1, a device for lubricating a frictional portion of each part to continue operation, and a cylinder. 1 for cooling the intake and exhaust valves 11 and 12
And a valve mechanism that opens and closes at a predetermined time, and an interrupter for blowing an electric spark at a predetermined time.

Further, in this internal combustion engine, a portion of the cylinder 1 located below the top dead center of the piston 2 and facing the peripheral surface of the cylinder 1 is provided with:
Second combustion chambers 5, 5 each communicating with the first combustion chamber 1a of the cylinder 1 and being opened and closed by the reciprocating motion of the piston 2 are provided so as to protrude outward, and the second combustion chambers 5, 5 are provided.
Exhaust valves 51, 51 are provided on the side of the cylinder 1 opposite to the peripheral surface side. As shown in FIGS. 1 and 2, the second combustion chambers 5, 5 each have a cylindrical body protruding from a position facing the peripheral surface of the cylindrical cylinder 1, and apply the most rotational force to the crankshaft 4. It is provided at a position corresponding to a position to be obtained, that is, around 30 degrees before the horizontal line of the rotation trajectory of the crankshaft 4 (around 30 degrees before the horizontal line in the operation stroke). The second combustion chamber 5 communicates with the first combustion chamber 1a of the cylinder 1 via an opening surface, and an exhaust valve 51 is provided on a bottom surface (surface opposite to the opening surface).

In the internal combustion engine having such a configuration, engine operation is continued as follows. FIG. 1 shows the suction stroke. In this suction stroke, the exhaust valve 11 is closed, the intake valve 12 is opened, and the exhaust valve 51 is closed. As piston 2 descends from top dead center,
When the air-fuel mixture is sucked into the cylinder 1 and the piston 2 reaches the bottom dead center, the first combustion chamber 1
As a matter of course, the second combustion chamber 5 is also filled with the air-fuel mixture.

Next, in the compression stroke shown in FIG. 3, the exhaust valve 11, the intake valve 12, and the exhaust valve 51 are closed at the same time as the piston 2 starts to move upward, and the cylinder 1 is sealed.
As the piston 2 rises, the air-fuel mixture in the first combustion chamber 1a and the second combustion chamber 5 is compressed, and the pressure and temperature rise. By the time the piston 2 reaches the top dead center position, that is, the piston 2
When passing through a position corresponding to an angle exceeding 0 degrees, the second combustion chamber 5 is completely closed by the piston 2 and is isolated from the first combustion chamber 1a.

In the operation stroke of FIG. 4, when the compression stroke ends and the piston 2 reaches the top dead center, the ignition plug 1
3, an electric spark flies, the mixture in the first combustion chamber 1 a of the cylinder 1 is ignited and burns rapidly, the pressure in the cylinder 1 rises, a pushing force is applied to the piston 2, and the crankshaft 4 Generates rotational force. When the piston 2 descends and the opening surface of the second combustion chamber 5 is opened, the explosive
The air-fuel mixture in the combustion chamber 5 is exploded (see FIG. 5). In other words, a second explosion occurs following the first explosion, and this explosive force gives the piston 2 a downward force again, and the crankshaft 4
Apply rotational force to The point at which the second explosive force acts is a point 3 on the horizon in the rotational orbit of the crankshaft 4.
This is around 0 degrees, which is the point at which the efficiency of applying a rotational force to the crankshaft 4 is highest. Therefore, by applying the rotational force twice to the crankshaft 4 with a time difference, the rotational force of the crankshaft 4 becomes uniform, the rotation of the crankshaft 4 becomes quick, and the engine efficiency is improved.

In the exhaust stroke shown in FIG. 6, the intake valve 12 is closed, the exhaust valve 11 and the exhaust valve 51 are opened, and the piston 2
As a result, the combustion gas is discharged to the outside of the cylinder 1.

[0021]

According to the present invention, as described above, the explosion in the first combustion chamber is followed by the explosion in the second combustion chamber in the working stroke during one cycle, that is, one cycle. Twice explosion, the internal volume (displacement) of the cylinder substantially increases and the combustion continues for a long time as compared with the case where only the first combustion chamber of a normal internal combustion engine is used. As a result, not only the rotational force of the crankshaft is increased and the output is increased, but also the rotational force of the crankshaft is not uneven, and the rotational efficiency of the crankshaft and the engine efficiency are improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an internal combustion engine (intake stroke) according to an embodiment.

FIG. 2 is a plan sectional view of the internal combustion engine according to the embodiment.

FIG. 3 is a cross-sectional view illustrating a compression stroke of the internal combustion engine according to the embodiment.

FIG. 4 is a sectional view showing an operation stroke of the internal combustion engine according to the embodiment.

FIG. 5 is a sectional view showing an explosion state in a second combustion chamber of the internal combustion engine according to the embodiment.

FIG. 6 is a sectional view showing an exhaust stroke of the internal combustion engine according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder 1a 1st combustion chamber 2 Piston 3 Connecting rod 4 Crankshaft 5 2nd combustion chamber 11 Exhaust valve 12 Intake valve 13 Spark plug 51 Exhaust valve

Claims (1)

(57) [Claims] 1. An internal combustion engine comprising: a cylinder having an exhaust valve, an intake valve, and a spark plug in an upper portion thereof; a piston reciprocating in the cylinder; and a crankshaft connected to the piston via a connecting rod. , The circumferential surface pair of the cylinder located below the top dead center of the piston
To the respective first combustion chambers of the cylinders
Combustion opened and closed by the reciprocating motion of the piston
A second combustion chamber having a cylinder protruding outwardly;
An exhaust valve is provided on the side opposite to the peripheral surface of
And the air-fuel mixture is sucked into the second combustion chamber, and during the compression stroke,
By piston before Ston reaches the top dead center position
The second combustion chamber is sealed, and in the working stroke, the first combustion chamber
The piston is pushed down by the combustion of the second combustion chamber.
An internal combustion engine characterized in that combustion in a second combustion chamber occurs at the time of opening .