JPS59229016A - Supercharged multi-cylinder internal-combustion engine - Google Patents

Abstract

PURPOSE:To reduce fluctuation in a supercharged pressure for a combustion cylinder and thereby to decrease loss of mechanical power of a piston, by forming cylinder chambers on upper and lower sides of the piston in a supercharging cylinder, and alternately compressing a suction air in the upper cylinder chamber and the lower cylinder chamber. CONSTITUTION:Upon rising of a piston 21 in a second cylinder 3, a suction air is compressed in an upper cylinder chamber 19, while air is sucked into a lower cylinder chamber 20. Upon lowering of the piston 21, air is sucked into the upper cylinder chamber 19, while a suction air is compressed in the lower cylinder chamber 20. Thus, two compression strokes per one reciprocating motion of the piston 21 are effected in the second cylinder 3, and a compression air in the two compression strokes is once stored in a surge tank 29. Then, it is supplied to first and second cylinders 3 and 4. Accordingly, it is possible to reduce fluctuation in a supercharged pressure for the first and second combustion cylinders 2 and 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-cylinder internal combustion engine in which some of the cylinders are used for supercharging other combustion cylinders.

In this way, a multi-cylinder engine is developed in which some of the cylinders are used as supercharging cylinders for other combustion cylinders.
7242, Japanese Patent Application Laid-Open No. 51-91416, and Japanese Patent Application Laid-open No. 52-76517, these prior art techniques pump air into the upper chamber of the cylinder when the piston in the supercharging cylinder descends. so as to inhale and then compress the air in the upper chamber of the cylinder as the piston rises.
While the air is compressed once during each reciprocation of the piston, at least one combustion cylinder is set to be in the intake stroke when the piston of this supercharging cylinder moves up, so that the supercharging cylinder is The air compressed in the cylinder is sent under pressure to the combustion cylinder. In this case, there is a one-to-one correspondence between the supercharging cylinder and at least one combustion cylinder; In order to perform the specified supercharging, the compression stroke volume in the supercharging cylinder must be larger than the stroke volume in the combustion cylinder by the volume corresponding to the supercharging (1 or 3 times the stroke volume of the normal combustion cylinder). (approximately twice as much), the engine as a whole becomes larger, and the stroke distance of the supercharging piston is large, so the reciprocating speed of the piston is fast, so the mechanical power loss associated with the reciprocating movement of the piston is also large ( The mechanical power associated with the reciprocating movement of the piston increases in proportion to the reciprocating speed of the piston), and the supercharging cylinder performs only one compression stroke compared to the combustion cylinder. First, since the fluctuations in the pulsation of the boost pressure are large, the fuel supply by the carburetor is unstable, and in other words, it is difficult to use the carburetor.

The present invention provides an internal combustion engine in which some of the plurality of cylinders are used as supercharging cylinders for other combustion cylinders, in which cylinder chambers are formed above and below the piston in the supercharging cylinder, and the piston is When the piston descends, air is sucked into the upper chamber of the cylinder while air is compressed in the lower chamber of the cylinder, and when the piston rises, air is sucked into the lower chamber of the cylinder,
The problem of the prior art is solved by compressing air in the upper chamber of the cylinder, in other words, by performing two compression strokes during one reciprocation of the piston.

Below, we will explain the drawings of embodiments in which the present invention is applied to a three-cylinder internal combustion engine. Commonly, it is a three-cylinder engine arranged in series, and the first
Cylinder (2) and third cylinder (4) have intake valves (6) <7
) with an intake port (8) (9), an exhaust port α with an exhaust valve 000D, and an ignition column 0 →
) (4) The second cylinder (3) between cylinder block O
A supercharger having a cylinder bore 08) formed in the cylinder head 07) on the upper surface of Q, and a piston 21) fitted into the cylinder bore α8) to form an upper cylinder chamber and a lower cylinder chamber (1). It is configured as a cylinder for use.

The piston (a) of the first cylinder (2) and the third cylinder (4)
The piston 21) of the second cylinder (3) moves up and down simultaneously in the same phase as the piston (c) of the second cylinder (3).
It is connected to the crankshaft (5) via connecting rods (C) (C) (C) so as to move up and down in the exact opposite direction to the pistons of the cylinders (C). 3 cylinders (4)
means that when the first cylinder (2) is in the explosion stroke, the third cylinder (4)
The firing order is 360 degrees in crank angle so that the intake stroke is
As shown in Figure 4, the second cylinder (3
) during the first rise of the piston (gl) of the third cylinder (4)
is the intake stroke, and the first cylinder (2) is set to enter the intake stroke when the piston Q1) of the second cylinder (3) next rises.

In addition, the intake manifold for the intake ports (8) (9) in the first cylinder (2) and the third cylinder (4)
The carburetor (c), which is an example of a fuel supply means, is in contact with the surge tank holder, and the first and third cylinders (2) (
4), the exhaust manifold (1) is connected to the exhaust port 0203.

The second cylinder (3) has a cylinder upper chamber a.
There is a suction port 0◇ that communicates with the lower cylinder chamber, a suction port 0 that communicates with the lower cylinder chamber, and a discharge port that communicates with the upper cylinder chamber 0 (G) and a discharge port that communicates with the lower cylinder chamber (A). ■ and these suction port 0.
]) A check valve-type suction valve (C) (G) and a discharge valve @ (C) are provided at the 0 port and the discharge port 0 port ■, respectively, and an air cleaner ( Connect the suction passage θ0 from the
]) is connected to the surge tank via.

In this configuration, the piston 12 of the second cylinder (3)
During the upward movement of the cylinder, intake air is compressed in the upper chamber 00 of the cylinder, and air is sucked in the lower chamber 00 of the cylinder.
In response to the downward movement of the piston Qυ, the upper cylinder chamber α sucks in air, and the lower cylinder chamber (A) compresses the intake air.
1) One reciprocating movement, that is, 2 per revolution of the crankshaft (5)
The compressed air for two times is stored in a surge tank etc. and then supplied to the first cylinder (2) and the third cylinder (4), so the first cylinder (for combustion) 2
) and the supercharging pressure for the third cylinder (4) is 1 per reciprocation of the piston of the supercharging cylinder, as in the prior art.
This is smaller than when only the compression stroke is performed, and the piston and
1) - Performing compression twice during reciprocating motion means that if the cylinder inner diameter and piston stroke are the same as in the prior art, the compression stroke volume will approximately double. In (3), the diameter of the cylinder bore (18) and/or the stroke of the piston 121) can be reduced.

Note that the above embodiment is for the second cylinder (3) in a three-cylinder engine.
In this case, the first cylinder (2) or the third cylinder (4) may be used as a supercharging cylinder, and the other cylinders may be used as combustion cylinders. In addition to the three-cylinder engine of the above embodiment, the compressed air compressed twice during one reciprocation in the supercharging cylinder is stored in a surge tank or the like, and then distributed and supplied to the other combustion cylinders. Therefore, it goes without saying that it can be similarly applied to multi-cylinder engines such as 4 cylinders or 6 cylinders, and furthermore, as in the above embodiment, the first and third combustion cylinders (2) (4) If the cylinder bore 08) of the second cylinder for supercharging (3) located between them is provided in the cylinder head αη, the interval between the first cylinder (2) and third cylinder (4) on both sides of Because it is narrower, the engine can be made smaller.

According to the present invention as described above, some cylinders among a plurality of cylinders are
In a multi-cylinder internal combustion engine configured as a supercharging cylinder for other combustion cylinders, cylinder chambers are formed above and below the piston in the supercharging cylinder, and intake air is alternately supplied to the cylinder upper chamber and cylinder lower chamber. It is characterized by compression.

This makes it possible to reduce fluctuations in supercharging pressure to the combustion cylinder, making it easy to use a carburetor as a fuel supply means, while also reducing the cylinder diameter and/or piston stroke of the supercharging cylinder, allowing the engine The overall size and weight can be reduced, and since the stroke of the piston in the supercharging cylinder can be shortened, the reciprocating speed of the piston is slowed down, which has the effect of significantly reducing mechanical power loss in the piston.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a plan view, FIG. 2 is a sectional view taken along line I-1 in FIG. 1, and FIG. It is a figure showing the stroke of each cylinder. (1)... Internal combustion engine, (2H4>... Combustion cylinder, (
3)...Supercharging cylinder, 08)...Cylinder bore, I21
)...-Piston, (I■...Cylinder upper chamber, (A)
...Cylinder lower chamber.

Claims (1)

[Claims] (1) In a multi-cylinder internal combustion engine in which some of the cylinders are configured as supercharging cylinders for other combustion cylinders, cylinder chambers are formed above and below the piston, and the upper and lower cylinder chambers and the lower cylinder chamber are formed. A supercharged multi-cylinder internal combustion engine characterized by compressing intake air alternately between the chamber and the chamber.