CN114439609A

CN114439609A - Multi-cylinder two-stroke engine capable of realizing time-sharing ignition

Info

Publication number: CN114439609A
Application number: CN202111663709.6A
Authority: CN
Inventors: 黄云龙; 杨广文; 李洲
Original assignee: No 60 Institute of Headquarters of General Staff of PLA
Current assignee: No 60 Institute of Headquarters of General Staff of PLA
Priority date: 2021-12-30
Filing date: 2021-12-30
Publication date: 2022-05-06

Abstract

The invention discloses a multi-cylinder two-stroke engine capable of realizing time-sharing ignition, which comprises two or more cylinders, a piston, a crankshaft connecting rod assembly, a crankcase and a rotating speed gear disc assembly, wherein the two or more cylinders are connected with the piston; the cylinder body is provided with an oil nozzle mounting hole, a spark plug mounting hole, a scavenging passage and an exhaust port. The piston reciprocates between the preset top dead center and the bottom dead center of the cylinder body, the front ends of the oil nozzle and the spark plug extend into the combustion chamber through the mounting hole, and the piston is provided with a piston pin and a piston ring. The crankshaft connecting rod assembly consists of a crankshaft and a connecting rod, two or more bearings, cylinder bodies and mounting holes of an air inlet manifold are arranged in the crankcase; the scavenging passage of the cylinder body is communicated with the crankcase, and fresh air enters the crankcase through the intake manifold and then enters the cylinder through the scavenging passage; the rotating speed fluted disc component consists of a fluted disc and a rotating speed sensor. The engine has small envelope and compact structure, can well balance the reciprocating motion moment of the crankshaft, and each cylinder independently ignites, thereby reducing the influence of the cylinder fault on the whole.

Description

Multi-cylinder two-stroke engine capable of achieving time-sharing ignition

Technical Field

The invention belongs to the technical field of industrial design of engines, and particularly relates to a multi-cylinder two-stroke engine capable of realizing time-sharing ignition.

Background

The two-stroke piston engine is widely applied to various unmanned aerial vehicles due to the advantages of compact structure, high boost power and the like. Compared with a four-stroke engine, the two-stroke engine has no intake valve and exhaust valve, a crankcase scavenging intake mode is generally adopted, and the crankcase inner cavities of the two-stroke engine are communicated with each other, which means that the scavenging, ignition and exhaust phases of a plurality of cylinders of the engine are the same. Therefore, problems are brought about, compared with time-sharing ignition, the stability of the rotating speed of the synchronously ignited engine is poorer, the crankshaft simultaneously bears higher pressure, and the requirement on the strength is higher. In order to balance the torque of crankshaft rotation, the arrangement form of cylinders of the two-stroke engine is generally symmetrical, and the outer envelope size of the engine is large. With the development of unmanned aerial vehicles, the requirements on small envelope and stability of piston engines are higher and higher, so that research on multi-cylinder time-sharing ignition two-stroke engines is necessary.

Disclosure of Invention

The invention aims to solve the problems of poor rotating speed stability, large pressure bearing capacity of a crankshaft and larger outer envelope size of an engine of a two-stroke engine

In order to realize the purpose of the invention, the invention provides a multi-cylinder two-stroke engine capable of realizing time-sharing ignition, which comprises two or more cylinders, a piston, a crankshaft connecting rod component, a crankcase and a rotating speed gear disc component, wherein the two or more cylinders are connected with the piston;

the cylinder consists of a cylinder body and a cylinder cover, and the cylinder cover is provided with an oil nozzle mounting hole coaxial with the cylinder body and a spark plug mounting hole positioned below the oil nozzle mounting hole; the cylinder body is provided with a scavenging passage and an exhaust port; the piston is arranged in the cylinder and reciprocates between a preset top dead center and a preset bottom dead center of a cylinder body of the cylinder; the sealed space formed by the piston and the cylinder cover when the piston moves to the top dead center is a combustion chamber, the front ends of the oil nozzle and the spark plug extend into the combustion chamber through the mounting hole, and a piston pin and a piston ring are arranged on the piston;

the crankshaft connecting rod assembly consists of a crankshaft and connecting rods with the number corresponding to that of the cylinders, wherein the small end of each connecting rod is arranged on the piston pin, and the large end of each connecting rod is arranged on the crankshaft; two or more bearings are arranged in the crankcase and are used for supporting the crankshaft connecting rod assembly; the crankcase is also provided with a cylinder body and an installation hole of an air inlet manifold, a scavenging passage of the cylinder body is communicated with the crankcase, and fresh air enters the crankcase through the air inlet manifold and then enters the cylinder through the scavenging passage; the rotating speed gear disc component consists of a gear disc and a rotating speed sensor, the gear disc is arranged on the crankshaft and rotates along with the crankshaft, and the rotating speed sensor is fixed on the crankshaft.

Further, the cylinders are arranged on the crankcase in a staggered mode, and the axial angles of two adjacent cylinders form 0-180 degrees; the axial angle between the oil nozzle mounting hole and the spark plug mounting hole is 30-60 degrees.

Furthermore, a middle disc is arranged on the crankshaft and positioned between two adjacent connecting rods; the middle disc is matched with the sealing ring and the crankcase to form a sealing structure, so that the crankcase is divided into sealing spaces corresponding to the number of cylinders.

Further, the cylinder body can independently advance the exhaust, further can realize that every cylinder body timesharing ignites.

Further, an oil interface is arranged on the air inlet manifold and used for independently lubricating the engine.

Further, the fuel injection of the fuel injection nozzle of the engine and the ignition of the spark plug are controlled by the ECU, and the fuel injection and ignition interval phase of two adjacent cylinders is the angle of the axes of the two adjacent cylinders.

Furthermore, the tooth root of fluted disc is evenly arranged and is provided with 1 and lacks the tooth, and ECU passes through speed sensor and gathers the crankshaft position and judge the phase place of every cylinder oil spout and ignition.

Further, the outer ring of the sealing ring is in interference fit with the crankcase, the inner ring of the sealing ring is made of polytetrafluoroethylene materials, and the sealing ring is attached to a middle disc on the crankshaft, can bear high temperature and linear speed, and does not need lubrication.

Furthermore, the rotating speed sensor is fixed on the crankcase, and the clearance between the rotating speed sensor and the fluted disc is 1 +/-0.5 mm.

Furthermore, the outer ring of the sealing ring is of a metal structure and is in interference fit with the inner cavity of the crankcase; when the crankshaft runs, the sealing ring cannot generate relative movement because the outer ring is in interference fit, and the resistance of the crankshaft is low and cannot be abraded because the material of the inner ring is soft.

Compared with the prior art, the invention has the remarkable improvements that: 1) compared with a horizontal opposed engine, the aircraft has smaller envelope and more compact structure, and is more suitable for an aircraft with higher requirement on the envelope; 2) the structural form of the engine can well balance the reciprocating motion moment of the crankshaft, and compared with an inline engine, the engine has the advantages that the operation is more stable, and the vibration level is better; 3) each cylinder independently ignites, if an ignition system of one cylinder breaks down, the ignition of other cylinders cannot be influenced, the limp running of the engine can be ensured, and flameout and parking are avoided.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

FIG. 1 is a schematic view of the cylinder structure of the present invention;

FIG. 2 is a schematic view of the overall structure of the present invention;

FIG. 3 is a schematic view of the internal structure of the crankcase of the present invention;

FIG. 4 is a partial schematic view of a second cylinder according to the present invention;

FIG. 5 is a partial schematic view of a first cylinder of the present invention;

FIG. 6 is a schematic view of the position of the oil union of the present invention;

the reference numbers in the figures are: 1. a first cylinder; 2. a second cylinder; 3. a middle disc; 4. rotating and sealing; 5. a crankcase; 6. a piston; 7. a scavenging path; 8. an exhaust port; 9. an oil jet; 10. a spark plug; 11. a first intake manifold; 12. a second intake manifold; 13. a first cylinder mounting hole; 14. a second cylinder mounting hole; 15. a first intake manifold mounting hole; 16. a second intake manifold mounting hole; 17. a fluted disc; 18. a rotational speed sensor; 19. and a lubricating oil joint.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, in the present embodiment, the cylinder is composed of a cylinder body and a cylinder cover, the cylinder cover is provided with an oil nozzle 9 mounting hole coaxial with the cylinder body, and a spark plug 10 mounting hole located below the oil nozzle mounting hole; the cylinder body is provided with a scavenging passage 7 and an exhaust port 8; the piston 6 is arranged in the cylinder and reciprocates between a preset top dead center and a preset bottom dead center of a cylinder body of the cylinder; a sealed space formed by the piston 6 and a cylinder cover when the piston moves to the top dead center is a combustion chamber, the front ends of an oil nozzle 9 and a spark plug 10 extend into the combustion chamber through a mounting hole, and a piston pin and a piston ring are arranged on the piston;

as shown in fig. 2, in the present embodiment, the engine is provided with two cylinders, namely a first cylinder 1 and a second cylinder 2, whose axes are different by 90 degrees, and the crankshaft in the present embodiment has two connecting rods in total. The small end of the connecting rod is arranged on the piston pin, and the large end of the connecting rod is arranged on the crankshaft; two or more bearings are arranged in the crankcase and are used for supporting the crankshaft connecting rod assembly. The crankcase passes through first cylinder body mounting hole 13 and the fixed first cylinder 1 of second cylinder body mounting hole 14, second cylinder 2, and the scavenge way and the crankcase intercommunication of two cylinder block. Meanwhile, the first and second intake manifolds 11 and 12 are mounted through the first and second intake

manifold mounting holes

15 and 16. Fresh air enters a crankcase from an air inlet manifold and then enters a cylinder through a scavenging passage; the rotating speed gear disc component consists of a gear disc and a rotating speed sensor, the gear disc is arranged on the crankshaft and rotates along with the crankshaft, and the rotating speed sensor is fixed on the crankshaft.

In this embodiment, as shown in fig. 3, the crankcase is a two-part structure, after the screws are installed, a communicating cavity is formed, the crankcase is provided with a cylinder mounting hole and an intake manifold mounting hole, the crankshaft connecting rod passes through the crankcase and is supported by bearings at two ends, and the connecting rod passes through the cylinder mounting hole on the crankcase and is connected with the piston 6.

Specifically, in the present embodiment, the seal ring is a rotary seal 4; a middle disc 3 is arranged between the two connecting rods, a rotary seal 4 is arranged on the middle disc 3, the outer diameter of the rotary seal 4 is of a metal structure and is in interference fit with the inner cavity of the crankcase 5; the inner diameter of the rotary seal 4 is made of polytetrafluoroethylene material and is attached to the middle disc 3, and the material can bear higher temperature and higher linear speed, and can ensure longer service life without lubrication. When the crankshaft runs, the rotary seal 4 does not generate relative movement because the outer diameter is in interference fit, and because the material of the inner diameter is soft, the resistance of the crankshaft is low and the crankshaft cannot be abraded when the crankshaft rotates. The rotary seal 4 and the middle disc 3 on the crankshaft divide the inner cavity of the crankcase 5 into two independent seal cavities, so that the air pressure change at two ends can not be influenced mutually.

As shown in fig. 2, 4 and 5, in the present embodiment, the first cylinder 1 and the second cylinder 2 are fixed to the crankcase 5 through the first cylinder mounting hole 13 and the second cylinder mounting hole 14, respectively; the first and second intake manifolds 11 and 12 are fixed to the crankcase 5 through first and second

cylinder mounting holes

13 and 14, respectively. Fresh air enters the crankcase 5 from the first intake manifold 11 and the second intake manifold 12, and then enters the first cylinder 1 and the second cylinder 2 through the two cylinder scavenging passages 7.

As shown in fig. 6, in the present embodiment, the engine adopts an independent lubrication mode, and the lubricating oil enters the crankcase 5 from the lubricating oil joint 19 arranged on the first intake manifold 11 or the second intake manifold 12 through the oil pump after being mixed with fresh air, so as to lubricate the cylinder block and the crankshaft connecting rod.

The realization principle and the working process of the invention are as follows: when the engine works normally, the piston reciprocates between the lower dead point and the upper dead point. When the piston moves downwards to the upper end of the scavenging passage, the air intake process starts, and fresh air enters the cylinder through the scavenging passage on the cylinder body; when the piston moves up to close the exhaust port, the cylinder begins to enter the compression process. At a suitable time thereafter, fuel or a fuel-air mixture is injected into the cylinder by the fuel injection nozzle; after a proper time, the engine spark plug starts to ignite, and the piston expands by heat to do work downwards. When the piston moves downwards to the exhaust port, exhaust is started, then the piston continues to move downwards until the upper end of the scavenging passage, a new air inlet process is started, and the engine repeats the working cycle.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A multi-cylinder two-stroke engine capable of realizing time-sharing ignition is characterized by comprising two or more cylinders, pistons, a crankshaft connecting rod assembly, a crankcase and a rotating speed gear disc assembly;

the cylinder consists of a cylinder body and a cylinder cover, wherein the cylinder cover is provided with an oil nozzle mounting hole coaxial with the cylinder body and a spark plug mounting hole positioned below the oil nozzle mounting hole; the cylinder body is provided with a scavenging passage and an exhaust port; the piston is arranged in the cylinder and reciprocates between a top dead center and a bottom dead center which are preset in a cylinder body of the cylinder; when the piston moves to the top dead center, a sealed space formed by the piston and a cylinder cover is a combustion chamber, the front ends of an oil nozzle and a spark plug extend into the combustion chamber through a mounting hole, and a piston pin and a piston ring are arranged on the piston;

the crankshaft connecting rod assembly consists of a crankshaft and connecting rods corresponding to the number of cylinders, wherein the small end of each connecting rod is arranged on the piston pin, and the large end of each connecting rod is arranged on the crankshaft; two or more bearings are arranged in the crankcase and are used for supporting the crankshaft connecting rod assembly; the crankcase is also provided with a cylinder body and mounting holes of an air inlet manifold, a scavenging passage of the cylinder body is communicated with the crankcase, and fresh air enters the crankcase from the air inlet manifold and then enters the cylinder through the scavenging passage; the rotating speed gear disc assembly is composed of a gear disc and a rotating speed sensor, the gear disc is arranged on the crankshaft and rotates together with the crankshaft, and the rotating speed sensor is fixed on the crankshaft.

2. The multi-cylinder two-stroke engine capable of realizing time-sharing ignition according to claim 1, wherein the cylinders are arranged on the crankcase in a staggered mode, and the axial angles of two adjacent cylinders are 0-180 degrees; the axial angle between the oil nozzle mounting hole and the spark plug mounting hole is 30-60 degrees.

3. The multi-cylinder two-stroke engine capable of achieving time-sharing ignition according to claim 1, wherein the crankshaft is provided with an intermediate disk which is positioned between two adjacent connecting rods; the middle disc is matched with the sealing ring and the crankcase to form a sealing structure, so that the crankcase is divided into sealing spaces corresponding to the number of cylinders.

4. The multi-cylinder two-stroke engine capable of achieving time-sharing ignition according to claim 1, wherein the cylinder blocks can independently intake and exhaust, and further time-sharing ignition of each cylinder block can be achieved.

5. The multi-cylinder two-stroke engine capable of achieving time-sharing ignition according to claim 1, wherein an oil port is arranged on the intake manifold and used for independently lubricating the engine.

6. The multi-cylinder two-stroke engine capable of achieving time-sharing ignition according to claim 1, wherein fuel injection from the fuel injection nozzle and ignition from the spark plug of the engine are controlled by the ECU, and the injection and ignition interval phase of two adjacent cylinders is the angle of the axes of two adjacent cylinders.

7. The multi-cylinder two-stroke engine capable of realizing time-sharing ignition according to claim 1 or 6, wherein the tooth roots of the fluted disc are uniformly arranged and provided with 1 missing tooth, and the ECU acquires the position of a crankshaft through a rotating speed sensor and judges the phase of oil injection and ignition of each cylinder.

8. The multi-cylinder two-stroke engine capable of achieving time-sharing ignition according to claim 3, wherein the outer ring of the sealing ring is in interference fit with the crankcase, and the inner ring of the sealing ring is made of polytetrafluoroethylene materials and is attached to a middle disc on the crankshaft.

9. The multi-cylinder two-stroke engine capable of achieving time-sharing ignition according to claim 1, wherein the rotation speed sensor is fixed on a crankcase, and the clearance between the rotation speed sensor and a fluted disc is 1 mm plus or minus 0.5 mm.

10. The multi-cylinder two-stroke engine capable of achieving time-sharing ignition according to claim 8, wherein an outer ring of the sealing ring is of a metal structure and is in interference fit with an inner cavity of the crankcase; when the crankshaft runs, the sealing ring cannot generate relative movement because the outer ring is in interference fit, and the resistance of the crankshaft is low and cannot be abraded because the material of the inner ring is soft.