JPH0311115A - Two-cycle engine - Google Patents

Abstract

PURPOSE:To improve the output without reducing the fuel consumption by arranging the second piston for opening the opened port of an air passage when the opened port of an air discharge passage is opened, oppositely to the first piston. CONSTITUTION:An air passage 18 for supplying the compressed air into a cylinder 4 is opened. The first piston 10 moves in reciprocation inside the cylinder 4 in correspondence with the turning angle of a crankshaft 8, and opens and closes the opened port of a scavenging passage 16 on the cylinder 4. The second piston 11 which is arranged oppositely to the piston 10 constitutes a combustion chamber between the piston 10, and moves in reciprocation in the cylinder 4 in correspondence with the turning angle of the crankshaft 8. The piston 11 opens the opened port of an air passage 18 when the opened port of an air discharge passage 17 is opened. Therefore, the waste gas left in the cylinder 4 can be positively discharged through the air discharge passage 17 by supplying the compressed air into the cylinder 4 through the air passage 18.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a two-stroke engine.

(Prior art) In general two-stroke engines installed in automobiles, motorcycles, etc., the opening of the exhaust passage and the opening of the insulation passage opening in the cylinder are opened and closed in a timely manner by a piston that reciprocates within the cylinder. , reman/compression" and "explosion/scavenging" processes are repeated.

[What does invention try to solve? Title a) By the way, in the conventional two-stroke engine,
When the opening of the exhaust passage in the cylinder is opened, the opening of the oscillating passage is opened so that the mixture entering through the scavenging passage causes the waste gas remaining in the cylinder to be discharged through the exhaust passage. ing.

For this reason, if the opening time of the scavenging passage is increased, the exhaust efficiency of exhaust gas can be improved, but the air-fuel mixture is also exhausted together with the open gas, resulting in a decrease in fuel efficiency.

On the other hand, if the opening time of the scavenging passage is shortened, the exhaust gas cannot be efficiently discharged, resulting in a decrease in engine output due to a decrease in the amount of air-fuel mixture.

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, an object of the present invention is to provide a two-stroke engine capable of improving output without reducing fuel efficiency.

[Failure to solve the problem]

The two-stroke engine according to the present invention has an air passage that opens inside the cylinder and supplies compressed air to the inside of the cylinder, and an air passage that reciprocates inside the cylinder in accordance with the rotation angle of the crankshaft. a first piston for opening and closing an opening of a scavenging passage in the cylinder;
is installed opposite to the first piston, and forms a combustion chamber between the first piston and the first piston inside the first cylinder, and is reciprocated inside the cylinder in accordance with the rotation angle of the crankshaft. and a second screw 1 for opening and closing the opening of the air passage at 35, so that the opening of the air passage is opened when the opening of the exhaust passage at 35 of the cylinder is opened.

(Function) According to the above configuration, by supplying pressure and air to the inside of the cylinder 81, the waste gas remaining in the cylinder can be actively exhausted through the exhaust passage.

(Example) Hereinafter, Δτ and ■ will be explained based on drawings showing examples.

FIGS. 1 and 2 conceptually illustrate a two-stroke engine according to the present invention, and exemplify a two-recycle medium-cylinder engine.

As shown in FIG. 1, the engine has a cam chamber 2 at one end inside the casing 1 and a crank chamber 3 at the other end.
Further, in a portion 1i located between the cam chamber 2J) and the crank chamber 3, a cylinder 4 is formed which allows the cam chamber 2 and the crank chamber 3 to communicate with each other.

The cam chamber 2 is formed to be wider than the cylinder 4, and a disc cam 6 fixed to a camshaft 5 is rotatably housed inside the cam chamber 2. The camshaft 5 is
As shown in FIG. 2, one end thereof protrudes to the outside of the casing 1, and a subblock 1-7 is fixed to this protruding outer end.

As shown in FIG. 1, the crank chamber 3, like the cam chamber 2, is formed wider than the cylinder 4, and the arm portion 8a of the crankshaft 8 is rotatably accommodated therein. There is. As shown in FIG. 2, the crankshaft 8 has both ends protruding outside the casing 1, and the sprocket 7 at this protruding outer end.
A sprocket 9 having the same diameter as this sprocket 7 is fixed to a portion corresponding to the sprocket 7.

Although not clearly shown in the drawings, the cylinder 4 has a cylindrical shape, and a pair of pistons 10 and 11 are fitted and housed therein so as to face each other.

The first piston 10 is connected to a crank pin 12 of the crankshaft 8 via a connecting rod 13, and the rotation of the crankshaft 8 causes the cylinder 4 to
is reciprocated inside.

The second piston 11 has the disc cam 6 on its end face 11a opposite to the first piston 10, and is pressed against the disc cam 6 by springs 14, 14, etc. when it is in motion. It is reciprocated inside the cylinder 4 by the action of the disc cam 6 due to the rotation of the force lever 1-5.

Further, as shown in FIGS. 1 and 2, the two-stroke engine has an intake passage 15, a scavenging passage 16, an exhaust passage 17, and an air passage 18 in the casing 1, respectively.

As shown in FIG. 1, the intake passage 15 is bored from the outside of the casing 1 toward the crank chamber 3, and a carburetor 21 is connected to its outer end via a reed valve 19 and a conduit 20. has been done.

As shown in FIG. 2, the scavenging passages 16 are arranged on both sides of the casing 1, and both ends thereof are open to the crank chamber 3 and the cylinder 4. this!
! The opening 16a on the crank chamber 3 side of the air passage 16 is formed at a position where it is always opened regardless of the reciprocating movement of the first piston 10, while the opening 16b on the cylinder 4 side It is formed at a position that is opened and closed by the reciprocating movement of the piston 10.

As shown in FIG. 1, the exhaust passage 17 is formed at a position where it can be opened and closed by the M2 piston 71 provided in the cylinder 4, and its outer end is connected to a conduit 22 and a turbine (not shown) of a turbocharger t-23. ) and is released to the atmosphere via the exhaust pipe 24.

The air passage 18 is the exhaust passage 17 in the cylinder 4.
The outer end is opened at a portion facing the conduit 25,
Jumper 26, lead @ 27, turbocharger 23 above
is released to the atmosphere via a compressor (not shown) and an intake pipe 28. Opening 18 of this air passage 18
As shown in FIG. 3, the edge 18a1 on the cam chamber 2 side is arranged at the same position as that of the exhaust passage 17, and on the other hand,
The edge 18a2 on the crank chamber 3 side is located closer to the cam chamber 2 than the exhaust passage 17. Note that this air passage 18 is formed so as to be inclined with respect to the axis of the cylinder 4.

In the two-stroke engine configured as described above, the first piston 10 and the second piston 11 are
A timing chain 29 is wound between the sprocket 7 of the camshaft 5 and the sprocket 9 of the crank shirt 1-8 so as to reciprocate according to the intake and exhaust timing as shown in FIG. 2 (as shown in FIG. 2). .

Hereinafter, the operation of the two-stroke engine will be explained based on this intake and exhaust timing.

First, as shown in FIG. 1, the rotation of the crankshaft 8 causes the first piston 10 to move to the bottom dead center (the two-point chain N
) to top dead center (solid line in the figure), this movement of the piston 10 creates negative pressure in the crank chamber 3, opens the reed valve 21, and the air-fuel mixture generated in the carburetor 21 flows into the intake passage 15. It is sucked into the crank chamber 3 through.

On the other hand, in this case, the second piston 11 closes the openings of the exhaust passage 17 and the air passage 18 with its peripheral wall, and these pistons 10.1
The air-fuel mixture that was in the air is compressed.

The compressed air-fuel mixture is ignited by the spark plug 30 and becomes f8.
The expanding gas pushes down the first piston 10,
This process produces an output, and the air-fuel mixture sucked into the crank chamber 3 is compressed.

When the first piston 10 moves downward from the position where the first piston 10 is at the top dead center until the rotation angle of the crankshaft 8 reaches approximately 85 degrees, the disc cam 6 and the spring 14 degrees 14... causes the second piston 11 to move upward, and first, only the exhaust passage 17 is opened, and exhaustion of the R gas is started.

The waste gas is vented to the atmosphere through the exhaust passage 17.4 pipe 22, the turbocharger 23 and the exhaust pipe 24, during which time the turbine (not shown) of the turbocharger 23 is rotated to drive the compressor (not shown). ) is operated to store compressed air in the chamber 26.

When the first piston 10 further moves downward and the rotation angle of the crankshaft 8 reaches approximately 135°, as shown in FIG. The piston 11 is further moved upward from the above-mentioned state, and the air passage 18 is opened together with the exhaust passage 17.
The opening 18a is opened and the compressed air stored in the chamber 26 is vigorously injected into the cylinder 4.

The injected compressed air generates a vortex within the cylinder 4 to promote exhaust gas discharge and purify the inside of the cylinder 4.

From this state, the rotation angle of the crankshaft 8 is approximately 14
When the temperature reaches 0°, the scavenging passage 16 that was blocked by the first piston 10 is opened, and the crank chamber 3 and the cylinder 4 are communicated with each other, and the compressed air-fuel mixture in the crank chamber 3 is transferred to the cylinder 4. The lI ratio is supplied within.

Immediately after the supply of air-fuel mixture into the cylinder 4 via the scavenging passage 16 begins, the second piston 11 is moved downward to close the air passage 18, and the supply of compressed air into the cylinder 4 is stopped. be done.

After this, the exhaust passage w117 and the scavenging passage 16 are both open until the first piston 10 passes the bottom dead center and the rotation angle of the crankshaft 8 reaches approximately 220 degrees. The air-fuel mixture is then filled into the cylinder 4.

When the first piston 10 rises until the rotation angle of the crankshaft 8 reaches approximately 220 degrees, this first piston 1
0, the scavenging passage 16 is closed and the supply of air-fuel mixture is stopped.

Further, when the rotation angle of the crankshaft 8 exceeds 240°, the exhaust passage 17 is moved downward by the second piston 11.
The second piston 11, which moves downward, and the first piston 10, which moves upward, cooperate to cool the air-fuel mixture in the cylinder 4, which is then ignited by the ignition plug 30 and exposed to light.

The following operations are repeated.

In addition, in the above embodiment, a medium cylinder engine employing the reed pulp 119 is exemplified, but the present invention may also be a multi-cylinder engine employing other pulps.

In addition, in the embodiment described above, since the second piston 11 is caused to reciprocate within the cylinder 4 by the action of the disc cam 6, by changing the profile of the disc cam 6, the air passage 18 and the exhaust Although the opening/closing timing of the passage 17 can be easily changed, the second piston 11 may be caused to reciprocate by other means. Further, although the exhaust passage 17 is opened and closed by the second piston 11, the exhaust passage 17 may be opened and closed by the first piston 10.

Further, in the above embodiment, compressed air to be supplied to the cylinder 4 is produced by the turbo charger 23, but the present invention is not limited to this.

C Effects of the Invention As described above, according to the two-stroke engine of the present invention, by supplying compressed air to the inside of the cylinder, residual gas remaining in the cylinder is actively removed through the exhaust passage. Since the fuel can be discharged, it is possible to improve the entrainment efficiency without causing a decrease in fuel efficiency.

··Crankshaft, 0...first piston, 1...Second bis i~n, 6...Scavenging passage, 7...Exhaust passage, 8...Air passage, 8a...Opening of air passage.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional front view conceptually showing a two-cycle engine according to the present invention, FIG. 2 is a cross-sectional side view conceptually showing a two-cycle engine according to the present invention, and FIG. FIG. 4, which is a sectional front view of a main part conceptually showing a two-stroke engine according to the invention, is a diagram showing intake and exhaust timing of the two-stroke engine according to the invention. 4...Cylinder, (chin-e-mi, -1-)

Claims (1)

[Claims] An air passage that opens inside the cylinder and supplies compressed air to the inside of the cylinder, and an air passage that reciprocates inside the cylinder in accordance with the rotation angle of the crankshaft to open and close the scavenging passage in the cylinder. A combustion chamber is formed between a first piston that is disposed opposite to the first piston and is inside the cylinder, and a combustion chamber is formed between the first piston and the first piston that and a second piston that is reciprocated inside the cylinder to open and close the opening of the air passage in the cylinder, so as to open the opening of the air passage when the opening of the exhaust passage in the cylinder is opened. A two-stroke engine characterized by the following.