JP2654591B2 - 4-cycle multi-cylinder engine - Google Patents

Description

The present invention relates to a four-cycle multi-cylinder engine.

[Conventional technology]

In recent four-cycle multi-cylinder engines, there is a tendency to increase the number of valves. For example, by increasing the number of valves for each cylinder, for example, arranging two intake valves per cylinder and increasing the valve opening area, the air-fuel mixture is increased. To increase the suction efficiency, thereby improving the output.

[Problems to be solved by the invention]

By the way, in a four-cycle multi-cylinder engine having a normal cylindrical piston, although there are three intake valves per cylinder arranged to further improve the intake efficiency of the air-fuel mixture, these three intake valves are provided. Are difficult to arrange in a line, and because they are arranged close to each other, the valve train mechanism is significantly complicated.

In order to solve this problem, conventionally, a four-cycle multi-cylinder engine in which a piston is formed in an elliptical column shape and four intake valves are juxtaposed in the major axis direction of the ellipse is provided.

However, the engine having the elliptical piston as described above is disadvantageous in balance and thermal strain as compared with the engine having the cylindrical piston,
Manufacturing of pistons and the like is complicated.

In view of the above circumstances, an object of the present invention is to provide a four-cycle multi-cylinder engine that is advantageous for balance and thermal distortion and that can improve the intake efficiency of the air-fuel mixture without complicating the manufacturing and processing operations. To provide.

[Means for solving the problem]

According to the present invention, the pistons of the cylinders having the same inner diameter and adjacent to each other are connected to the crankpins of the same phase via the connecting rods, respectively, while individual main combustions are respectively provided at portions of the cylinder head opposed to the pistons. A chamber is further formed, and in each main combustion chamber, one end of an exhaust port opened and closed by an exhaust valve is opened on one side of the center plane including the axis of the pair of pistons, and on the other side of the center plane. In a four-stroke multi-cylinder engine in which one end of a main intake port opened and closed by a main intake valve is opened, at least a portion deviated toward the main intake valve from the center plane between the main combustion chambers. At one place, a sub-combustion chamber having a smaller volume than the main combustion chamber and connecting these main combustion chambers to each other is provided. Form, together with the thereby opening the one end of the intake port to the site to be opening at one end and on the substantially straight line of the main intake port in addition the sub-combustion chamber,
A sub intake valve for opening and closing the intake port is provided.

[Action]

According to the above configuration, when the auxiliary intake valve is opened, the air-fuel mixture is sucked into the auxiliary combustion chamber through the intake port,
Further, the air-fuel mixture sucked into the sub combustion chamber reaches a pair of main combustion chambers.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing examples.

FIGS. 1 to 4 conceptually show a main part of a four-cycle multi-cylinder engine according to the present invention, and illustrate a DOHC type two-cylinder engine mounted on a motorcycle.

As shown in FIGS. 2 and 3, this engine
It has a pair of pistons 1,1. The pistons 1, 1 are formed in a columnar shape of the same size, and are fitted in sleeves 3, 3 which are embedded in the cylinder block 2 and are adjacent to each other. The sleeves 3, 3 are cylindrical and have their upper ends connected to each other.
The cylinder head mounting surface 2a has an approximately figure-eight shape.

Although not explicitly shown in the figure, the pair of pistons 1,1
Are connected via a connecting rod to crankpins having the same phase on the crankshaft.

On the other hand, as shown in FIG. 1, a cylinder head 4 of the engine has a pair of recesses 4 on a cylinder block mounting surface 4a.
b, 4b. The recesses 4b, 4b are formed at portions of the cylinder block 2 opposite to the pistons 1, 1, respectively, and two ends of the main intake port 4c and two ends of the exhaust port 4d are opened therein. These main intake ports 4c, 4c, 4c, 4c and exhaust ports 4d, 4d, 4d, 4d are respectively provided with concave portions 4b,
Openings in 4b are arranged one by one along a plane including the axis of the pair of pistons 1 and 1, and the other ends of the openings are opened on opposite side walls of the cylinder head 4. As is clear from the figure, the other end of each of the main intake ports 4c, 4c, 4c, 4c merges with each of the recesses 4b, 4b, and a vaporizer having the same diameter at each merge end. It has 5,5.

Further, two main intake valves 6 and two exhaust valves 7 are provided in the recesses 4b, 4b, respectively. The main intake valves 6, 6, 6, 6 are arranged at positions where the openings of the main intake ports 4c, 4c, 4c, 4c are closed.
Are simultaneously opened and closed by the intake valve camshaft 10 disposed at the same time. The exhaust valves 7, 7, 7, 7 are arranged at positions closing the openings of the exhaust ports 4d, 4d, 4d, 4d, similarly to the main intake valves 6, 6, 6, 6, described above. They are simultaneously opened and closed by the exhaust valve cam shaft (not shown) at the same time.

Further, the cylinder head 4 has a recess 4e formed in the cylinder block mounting surface 4a. The concave portion 4e has a smaller volume than each of the pair of concave portions 4b, 4b, and is disposed at a position deviated toward the main intake valve 6, 6,... Between the concave portions 4b, 4b. A pair of recesses 4b, 4b
Are communicated with each other.

One end of an intake port 4f communicates with the inside of the recess 4e. The intake ports 4f are connected to the main intake ports 4c, 4c, 4c, 4c communicating with the pair of recesses 4b, 4b.
It is open in a part that is substantially in line with the opening of
The other end is opened between the openings of the main intake ports 4c, 4c, 4c, 4c on the side wall of the cylinder head 4. As is apparent from the drawing, the opening of the side wall of the cylinder head 4 at the intake port 4f has a carburetor connected to the main intake ports 4c, 4c, 4c, 4c.
A vaporizer 8 smaller in diameter than 5,5 is connected.

The sub intake valve 9 is provided in the recess 4e. As shown in FIG. 4, the auxiliary intake valve 9 is disposed at a position that closes the opening of the intake port 4f, and is a cam for an intake valve that opens and closes the above-described main intake valves 6, 6, 6, 6. By the shaft 10, these intake valves 6, 6, 6,
It is opened and closed at the same time as 6. Reference numeral 11 in FIG. 4 denotes a swing arm type hydraulic lash adjuster, which is attached to the main intake valves 6, 6, 6, 6 and the exhaust valves 7, 7, 7, 7, in addition to the auxiliary intake valve 9. Is also provided. Reference numeral 12 in FIGS. 3 and 4 denotes a valve recess for the auxiliary intake valve 9 provided at the connecting portion of the sleeves 3,3. further,
Reference numeral 13 in FIGS. 1 and 2 is a spark plug mounting hole.

In the engine as described above, as shown in FIG. 2, when the cylinder head 2 is mounted on the cylinder block 4, the pistons 1 occupying the recesses 4b, 4b, the inner peripheral surfaces of the sleeves 3, 3 and the top dead center are formed. , 1 by the upper surface of the main combustion chamber 14,
14 are defined, and the main combustion chambers 14, 14 are interposed between the main combustion chambers 14, 14 by the connection of the recess 4e and the sleeves 3, 3.
Are defined, and a sub-combustion chamber 15 is defined.

Now, the main intake valves 6,6,6,6 in the main combustion chambers 14,14 are operated by the intake valve cam shaft 10, and the main intake ports 4c, 4c, 4c, When 4c is opened, the air-fuel mixture from the carburetors 5, 5 into the main combustion chambers 14, 14 and the sleeves 3, 3 in the negative pressure state through the main intake ports 4c, 4c, 4c, 4c. Inhaled.

At this time, in the sub-combustion chamber 15 communicating with the main combustion chambers 14, 14, the sub-intake valve 9 is operated at the same time as the main intake valves 6, 6, 6, 6, so that the intake port 4f is opened. .

Therefore, in the engine, the air-fuel mixture is also sucked from the carburetor 8 into the main combustion chambers 14 and 14 and into the sleeves 3 and 3 via the intake port 4f and the sub-combustion chamber 15. The intake efficiency of the air-fuel mixture can be improved as compared with an engine in which two intake valves are provided.

In addition, since the piston 1 and the sleeve 3 each have a circular cross section as in the prior art, a situation in which the balance and thermal strain are disadvantageous, and the production and processing work thereof are complicated. No invite.

In addition, since the openings of the main combustion chambers 14 and 14 at the main intake ports 4c, 4c, 4c and 4c and the opening of the sub-combustion chamber 15 at the intake port 4f are arranged substantially in a straight line, the main opening and closing of these are performed. The intake valves 6, 6, 6, 6 and the auxiliary intake valve 9 can be operated by the same intake valve cam shaft 10, and the valve operating mechanism is not significantly complicated.

In the above embodiment, the main combustion chambers 14 and 14 of the two cylinders are used.
Are communicated with each other by the auxiliary combustion chamber 15, but in the present invention, the combustion chambers of three or more cylinders may be communicated with each other. In addition, although one set of cylinders communicating the main combustion chambers 14 and 14 is illustrated, an engine including a plurality of sets of cylinders may be used. Furthermore, DOHC mounted on motorcycles
Although an expression engine is illustrated, it is not necessarily limited to these.

In the above embodiment, one intake port 4f is opened in the sub-combustion chamber 15 and one sub-intake valve 9 is disposed in the sub-combustion chamber 15. However, in the present invention, the intake The port 4f and the sub intake valve 9 may be plural. Furthermore, in the sub-combustion chamber 15, only the intake port 4f is opened and only the sub-intake valve 9 is provided. In the four-cycle multi-cylinder engine according to the present invention, in addition to these, the sub-combustion chamber 15 is also provided. Alternatively, an exhaust port may be opened, and an exhaust valve may be provided.

〔The invention's effect〕

As described above, according to the four-cycle multi-cylinder engine of the present invention, the efficiency of air-fuel mixture intake can be improved by using the cylindrical piston, which is advantageous for balance and thermal distortion, and is easy to machine. The output can be improved by the work.

[Brief description of the drawings]

FIG. 1 is a bottom view conceptually showing a cylinder head portion applied to a four-cycle multi-cylinder engine according to the present invention, and FIG. 2 is a conceptual diagram showing a main part of the four-cycle multi-cylinder engine according to the present invention. FIG. 3 is a perspective view conceptually showing a cylinder block portion applied to a four-cycle multi-cylinder engine according to the present invention, and FIG. 4 is a line IV-IV in FIG. It is an expanded sectional view. 1 ... Piston, 2 ... Cylinder head, 4c ... Main intake port, 4d ... Exhaust port, 4f ... Intake port, 6 ... Main intake valve, 7 ... Exhaust valve, 9 ... Sub intake valve, 14: Main combustion chamber, 15: Sub combustion chamber.

Claims (1)

(57) [Claims] 1. The pistons of cylinders having the same inner diameter and being adjacent to each other are connected to crank pins of the same phase via connecting rods, respectively, while individual cylinder heads are respectively provided at portions facing the pistons. Forming a main combustion chamber; further, in each main combustion chamber, one end of an exhaust port opened and closed by an exhaust valve is opened on one side of the center plane including the axis of the pair of pistons, and In a four-cycle multi-cylinder engine in which one end of a main intake port opened and closed by a main intake valve is opened on the other side, a portion deviated toward the main intake valve side from the center plane between the main combustion chambers. A sub-combustion chamber having a smaller volume than the main combustion chamber and communicating the main combustion chambers with each other at at least one position The sub-combustion chamber further comprises a sub-intake valve for opening one end of the intake port at a position substantially in line with one end opening of each main intake port, and for opening and closing the intake port. 4 cycle multi-cylinder engine.