JP2020084971A - Engine driven by parallel synchronous piston - Google Patents

Abstract

To solve a problem of a small engine, which is in general a trunk piston engine, in which fuel or combustion gas enters into a crank area and a lubricant oil cannot be distinguished, and a structural problem of a conventional medium-sized cross head engine in terms of a disassembly maintenance as many structures are provided which are merely reduced in a similar figures of a large-sized cross head engine, and further a problem of a conventional single-row cylinder structure for meeting needs of future combustion improvement and high efficiency.SOLUTION: Two sets of pistons 2 are connected to one set of commonly-shared cross head 3 and driven on the same engine stroke so as to solve the above problems. The structure can also be applied to a two-stroke engine and four- stroke engine. Also, an engine structure provided herein can meet needs for high efficiency and environmental countermeasures of the engine such as discriminating collection of exhaust gas by temperature, improvement in cooling a combustion chamber, and improvement in combustion by connecting the two sets of combustion chambers.SELECTED DRAWING: Figure 1

Description

The present invention connects both pistons 2 of two sets of cylinders to one set of common crossheads 3, operates both pistons 2 in the same engine stroke, and connects one set of connecting rod 4 and one set of crank. The present invention relates to the structure of a crosshead reciprocating engine that applies a rotational force to one crankshaft 5b via an arm 5a.

There are two types of reciprocating engines, a trunk piston type and a crosshead type, both of which are used according to the engine application. The crosshead type can easily receive the lateral thrust generated by the crank mechanism with a crosshead structure and enlarge the engine, and can separate the cylinder area 1x and the crank area 5x by the piston rod airtight device 2e, and the lubricating oil. It is widely used in large-scale two-stroke marine engines because it can be reasonably selected and managed. However, the structure is more complicated and the engine height is higher than that of the trunk piston type.

On the other hand, the trunk piston type has a simple structure and can keep the engine height low, but it is difficult to apply it to a large engine because the piston itself needs to receive the lateral thrust generated by the crank mechanism. Further, since the cylinder area 1x and the crank area 5x cannot be isolated by the piston rod airtight device 2e unlike the crosshead type, fuel and combustion gas may flow into the crank area 5x. Also, the cylinder oil and system oil cannot be separated. It is widely used in small and medium-sized 4-stroke engines.

JP2012-87781 JP2012-167664

When a crosshead type is adopted for a conventional reciprocating engine, the height of the engine is high, so there is a dimensional restriction on the installation location. Generally, the crosshead type is adopted for engines with a cylinder inner diameter of less than 300 mm. Not not. Further, in the conventional medium-sized crosshead engine having a cylinder inner diameter of 300 mm or more, the large crosshead engine has a similar structure and a small size, and workability when disassembling the engine for maintenance or repair is not good. There's a problem.

In recent years, a dual fuel engine that uses both liquid fuel (example: petroleum fuel) and gas fuel (example: natural gas) has been adopted. In the conventional trunk piston type, cylinder oil and system oil are used due to its structure. Since there is basically no separation, there is the problem that rational selection and management of lubricating oil cannot be performed.

Further, when using a conventional trunk piston type and natural gas in a premixed combustion system, an airtight device for separating the piston area 1x from the crank area 5x is not provided, so that it is supplied to the inside of the cylinder 1. If the premixed fuel remains unburned in a gaseous state and leaks from the sliding surface of the cylinder 1 and the piston 2, it will immediately enter the crank area, and there is a risk of ignition and explosion for some reason. There is a problem.

Even in the conventional crosshead type and trunk piston type, by considering the engine stroke of each cylinder independently and performing this engine stroke individually, it is possible to cope with environmental problems of exhaust gas and high efficiency. Is structurally limited.

Therefore, according to the present invention, two sets of pistons 2 in the rows A and B are connected to a common set of crossheads 3 and both pistons 2 are operated in the same engine stroke, so that the cylinders can be operated more than the conventional engine. As a result of being able to reduce the inner diameter, the height of the engine can be reduced, so that it is possible to realize an engine having a cylinder inner diameter of less than 300 mm, which has not been crossheaded conventionally. Further, by connecting the combustion chambers of the two sets of cylinders A and B with the combustion chamber connector 1c, a scavenging method that is not possible with a conventional engine with a single set of single cylinders, Adopt a combustion improvement method.

According to the present invention, by dividing a conventional single row cylinder into two pairs of cylinder 1 of row A and row B, the inner diameter of the cylinder is reduced by about 30% as compared with the case of one conventional cylinder. As a result, the height of the engine can be reduced by 30%, so that even a small engine, which has been difficult to crosshead in the past, can be crossheaded.

Further, according to the present invention, it is possible to adopt a telescopic method or a swing lever method for supplying the lubricating oil into the piston 2, and a sufficient amount of lubricating oil can be supplied to the piston 2. As a result, the temperature of the piston 2 can be lowered as compared with the prior art, which can contribute to the suppression or avoidance of pre-ignition and knocking in the premixed combustion type engine.

Further, according to the present invention, since the boss structure for the piston pin, which is conventionally provided in the piston 2 for connecting with the connecting rod 4, is not required, the structure of the piston 2 can be simplified and the heat distribution can be made uniform. Since it is easy to generate, the cooling of the piston is improved, and it is possible to contribute to suppressing or avoiding the occurrence of pre-ignition or knocking in the engine of the premixed combustion system.

As a specific example of the present invention, in the case where the present invention is applied to a four-stroke engine, immediately before the original exhaust stroke of the four-stroke engine, one cylinder 1 is connected to the other through the air supply hole provided in the lower portion. Since a cross scavenging (= cross scavenging) stroke can be added using the exhaust hole provided in the lower part of the exhaust gas, it is possible to recover by discrimination by the temperature of the exhaust gas, improve the cooling of the exhaust valve and the cylinder head part, and the combustion chamber of two sets of cylinder It is possible to adopt a combustion improvement method by connecting. Note that a patent application for this effect has been separately filed, so a description thereof will be omitted here.

As another specific example of the present invention, when the present invention is applied to a two-stroke engine, an air supply valve is installed at the top of the cylinder instead of the exhaust valve installed at the top of the conventional cylinder. As a result, it is possible to perform discriminative recovery according to the temperature of exhaust gas, abolishment of an exhaust valve exposed to high-temperature exhaust gas, improvement of cooling of a cylinder head portion, improvement of combustion, and the like. Note that a patent application for this effect has been separately filed, so a description thereof will be omitted here.

1 is a cross-sectional view of an engine structure showing an embodiment.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the cross-sectional concept of this structure. Two sets of cylinders 1 in rows A and B are operated in the same engine stroke, and the reciprocating motion of both pistons 2 is transmitted to one set of connecting rods 4 through one set of shared crossheads 3. This is a basic structure that applies a rotational force to one crankshaft 5b. The rotation direction of the crankshaft 5b may be right rotation or left rotation.

The cylinder area 1x and the crank area 5x are separated by both piston rod airtight devices 2e in the rows A and B. Thrust shoes 3b are provided at both ends of the crosshead 3, slide on a thrust guide 3a provided on the engine frame 6, and receive a lateral thrust generated by the connecting rod 4.

If the cylinders 1 of rows A and B are connected by the combustion chamber connector 1c, the combustion chambers of both cylinders 1 can be regarded as one combustion chamber and used. By this connection, for example, it is possible to inject the fuel of diffusion combustion (eg petroleum fuel) from the combustion chamber of the row A cylinder to the combustion chamber of the row B cylinder or vice versa, so that the fuel is sprayed into the cylinder. Can be done effectively.

Exhaust valves, intake valves, intake valves, etc. can be installed in the cylinder 1 of the A-row or B-row, respectively, and these valves of the A-row and B-row cylinders are collectively installed in the combustion chamber coupler 1c. You can also Further, the fuel supply device can be installed in the row A cylinder 1 or the row B cylinder 1, respectively, or the fuel supply devices in the rows A and B can be collectively installed in the combustion chamber coupler 1c. ..

1 cylinder 1c combustion chamber connector 1x cylinder area 2 piston 2e piston rod airtight device 2d piston rod 3a thrust guide 3b thrust shoe 3c crosshead pin 4 connecting rod 5a crank arm 5b crankshaft 5c crankpin 5x crank area 6 engine mount

Claims (3)

In a reciprocating engine, both pistons 2 of two sets of cylinders (hereinafter referred to as A-row and B-row) are connected to a common set of crossheads 3, and the reciprocating motion of the crossheads 3 is commonly used. Is transmitted to one set of crank arms 5a via the connecting rod 4 of No. 1 and both pistons 2 in rows A and B are operated in the same engine stroke, thereby giving a rotational force to one crankshaft 5b. And the engine. The engine according to claim 1, wherein in the engine, the cylinder area 1x and the crank area 5x are separated by two sets of piston rod airtight devices 2e. In the above engine, the crosshead 3 receives the lateral thrust received from the connecting rod 4 by the slide shoes 3b provided at both ends of the crosshead 3 and the thrust guide 3a fixed to the engine mount. The engine according to claim 1 and claim 2.

Images