CN115163289A - A Swirl Spray Tumble Combustion System for Opposed Piston Compression Ignition Engine - Google Patents

Abstract

The invention provides a swirl spray tumble combustion system of an opposed piston compression ignition engine, which comprises opposed pistons, an oil sprayer, a combustion chamber, a cylinder sleeve, swirl chambers and guide screens, wherein the opposed pistons are arranged in the cylinder sleeve, the combustion chamber is formed in the middle of the opposed pistons, the swirl chambers are symmetrically arranged on two sides of the cylinder sleeve, each swirl chamber is communicated with one guide screen, and the oil sprayer is arranged in each swirl chamber. The swirl spray tumble combustion system of the opposed piston compression ignition engine disclosed by the invention has the advantages that the structural characteristics of the asymmetric semi-willow leaf combustion chamber of the opposed piston are utilized near the top dead center, and the swirl motion is formed in a cylinder under the action of the spray jet flow at the outlet of the guide screen, so that the oil-gas mixing is accelerated, the ignition stagnation period and the combustion duration are shortened, and the combustion efficiency is improved.

Description

A Swirl Spray Tumble Combustion System for an Opposed Piston Compression Ignition Engine

technical field

The invention belongs to the technical field of opposed-piston compression-ignition engines, in particular to a swirling spray tumble combustion system of an opposed-piston compression-ignition engine.

Background technique

Compared with the traditional reciprocating piston engine, the opposed piston engine has the characteristics of compact structure, high power frequency and good dynamic balance due to the cancellation of the cylinder head and the valve train. However, since the ventilation process is realized through the intake and exhaust ports on the cylinder liner, the ventilation is organized by forming a spiral motion, and the exhaust gas is difficult to discharge quickly. In order to ensure the scavenging efficiency, it is usually necessary to increase the air supply ratio and increase the exhaust opening phase. . At the same time, due to the compact structure of the opposed-piston compression ignition engine, the injector is usually placed on the side. The fuel is injected laterally into the cylinder, so that the distance from the injector outlet to the wall collision point is short, and the atomization of the spray space is insufficient. Usually, the secondary crushing of the collision wall is used to form a mixture, resulting in an increase in the amount of fuel wet wall. In addition, the exhaust opening phase is advanced, resulting in further compression of the timing of the in-cylinder mixture formation and combustion process. Combining the above factors, such engines often have problems of low combustion efficiency and insufficient combustion due to uneven mixing. Therefore, improving the spray quality and optimizing the flow field structure in the cylinder can fundamentally improve the mixture formation and combustion characteristics of the opposed-piston compression ignition engine. The common optimization methods are mostly concentrated on the arrangement of the intake and exhaust ports. By changing the radial inclination of the gas port, the vortex motion is enhanced, but the effect on the spray combustion process is limited.

SUMMARY OF THE INVENTION

In view of this, the present invention aims to propose a swirling spray tumble combustion system for an opposed-piston compression ignition engine to solve the problem of low combustion efficiency of the engine.

In order to achieve the above object, the technical scheme of the present invention is achieved in this way:

A swirling spray tumble combustion system for an opposed-piston compression ignition engine, comprising opposed pistons, an injector, a combustion chamber, a cylinder liner, a swirl chamber and a guide screen, an opposed piston is installed inside the cylinder liner, and the middle of the opposed piston A combustion chamber is formed, swirl chambers are installed symmetrically on both sides of the cylinder liner, each swirl chamber is communicated with a guide screen, and the tangential direction of the outlet of the guide screen matches the shape of the combustion chamber, and a nozzle is installed inside each swirl chamber. oiler.

Further, the shape of the swirl chamber is close to a spherical shape, and is located near the top dead center of the engine.

Further, the guide screen is in a tapered streamline shape from the inlet to the outlet.

Further, the combustion chamber is a semi-willow shape.

Further, the opposed pistons are of asymmetrical structure and are arranged oppositely.

Further, near the top dead center of the engine, the semi-willow-shaped combustion chambers on both sides form an elliptical-like combustion chamber.

Compared with the prior art, the swirling spray tumble combustion system of the opposed piston compression ignition engine described in the present invention has the following advantages:

(1) The swirling spray tumble combustion system of the opposed piston compression ignition engine according to the present invention, near the top dead center, utilizes the structural features of the asymmetric half-willow combustion chamber of the opposed piston, combined with the guide screen Under the action of the outlet spray jet, a tumble movement is formed in the cylinder, which accelerates the mixing of oil and gas, shortens the ignition delay period and combustion duration, and improves the combustion efficiency.

(2) In the swirling spray tumble combustion system of the opposed piston compression ignition engine according to the present invention, through the tumble motion formed by the asymmetric half willow leaf combustion chamber structure of the opposed piston in the combustion process, the The process is conducive to exhaust gas discharge and improves engine scavenging efficiency.

(3) In the swirling spray tumble combustion system of the opposed piston compression ignition engine according to the present invention, the phase difference existing at the top dead center of the opposed pistons can be matched with the position of the exit of the guide screen, and the compression ratio can be realized near the top dead center. Rapidly increase, further improve the combustion isovolume, and improve the combustion efficiency.

Description of drawings

The accompanying drawings constituting a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the attached image:

1 is a schematic diagram of a swirling spray tumble combustion system of an opposed piston compression ignition engine according to an embodiment of the present invention;

2 is a schematic diagram of the working fluid flow of a swirling chamber swirling spray tumble combustion system in a compression process according to an embodiment of the present invention;

3 is a schematic diagram of the working fluid flow of the swirling spray tumble combustion system in the combustion process according to the embodiment of the present invention;

4 is a schematic structural diagram of a swirling spray tumble combustion system near top dead center according to an embodiment of the present invention.

Description of reference numbers:

1- Opposed piston; 2- Fuel injector; 3- Fuel spray; 4- Combustion chamber; 5- Cylinder liner; 6- Swirl chamber; 7- Guide screen; The working fluid streamline on the upper side of the process; 10- the working fluid streamline on the lower side of the combustion process; 11- the exit of the guide screen.

Detailed ways

It should be noted that the embodiments of the present invention and the features of the embodiments may be combined with each other under the condition of no conflict.

In the description of the present invention, it should be understood that the terms "center", "portrait", "horizontal", "top", "bottom", "front", "rear", "left", "right", " The orientation or positional relationship indicated by vertical, horizontal, top, bottom, inner, outer, etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and The description is simplified rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. In addition, the terms "first", "second", etc. are used for descriptive purposes only, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first", "second", etc., may expressly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

A swirl spray tumble combustion system for an opposed piston compression ignition engine, as shown in Figures 1 to 4, includes opposed piston 1, fuel injector 2, combustion chamber 4, cylinder liner 5, swirl chamber 6 and a guide The screen 7, the opposite piston 1 is installed inside the cylinder liner 5, the combustion chamber 4 is formed in the middle of the opposite piston 1, the swirl chambers 6 are installed symmetrically on both sides of the cylinder liner 5, and each swirl chamber 6 is communicated with a guide screen 7, each A fuel injector 2 is installed inside the swirl chamber 6 .

The fuel injector 2 is installed in the swirl chamber 6 , and the fuel spray is accelerated and evaporated under the action of strong vortex entrainment in the swirl chamber 6 . The swirl chamber 6 is nearly spherical in shape and is located near the top dead center of the engine.

The guide screen 7 is tapered and streamlined from the inlet to the outlet. The fuel vapor is subjected to the tapering action of the flow area of the guide screen 7 , and the spray forms a jet at the outlet 11 of the guide screen and enters the cylinder liner 5 . The tangential direction of the outlet 11 of the guide screen 7 is adapted to the shape of the combustion chamber 4 .

The combustion chambers 4 on each side are half willow leaves; the opposed pistons 1 are of asymmetrical structure and are arranged opposite to each other. Near the top dead center of the engine, the semi-willow-shaped combustion chambers 4 on both sides form a large elliptical-shaped combustion chamber. Using the structural characteristics of the asymmetric semi-willow combustion chamber 4 of the opposed piston 1, combined with the guide screen outlet 11. Under the action of the spray jet, a tumble movement is formed in the cylinder, which accelerates the mixing of oil and gas, shortens the ignition delay period and combustion duration, and improves the combustion efficiency.

The asymmetric half-willow combustion chamber 4 of the opposed piston 1 has a tumble motion formed during the combustion process, which is beneficial to the exhaust gas discharge during the exhaust process and improves the scavenging efficiency of the engine. If there is a phase difference at the top dead center of the opposed pistons, in conjunction with the position of the guide screen outlet 11, the compression ratio can be rapidly increased near the top dead center, further improving the combustion isovolume and improving the combustion efficiency.

The working principle of a swirling spray tumble combustion system for an opposed piston compression ignition engine is as follows:

1. In the engine compression process, as shown in FIG. 2 , the working medium is subjected to the negative pressure of the guide screen 7 and enters the swirl chamber 6 to form a swirl motion in the cavity of the swirl chamber 6 .

2. The fuel injection starts, as shown in Figure 1, the fuel spray 3 accelerates its evaporation under the action of the strong vortex entrainment in the swirl chamber 6; the fuel vapor is subjected to the tapering effect of the flow area of the guide screen 7, and the spray is sprayed at the guide screen outlet. 11 to form a jet into the cylinder.

As shown in FIG. 3, using the structural characteristics of the combustion chamber 4 of the opposed piston 1, the semi-willow-shaped combustion chambers 4 on both sides constitute an elliptical combustion chamber. Combined with the spray jet from the guide screen outlet 11, a tumble flow is formed in the cylinder. movement to accelerate the oil-air mixing.

3. There is a phase difference at the top dead center of the opposing piston 1. Near the top dead center, as shown in Figure 4, the guide screen outlet 11 is blocked by the lower opposing piston 1, the swirl chamber 6 is isolated from the cylinder, and the working volume is rapidly reduced , the compression ratio is rapidly increased, and the combustion isovolumetric capacity is further improved, and the combustion efficiency is improved.

4. The opposed piston 1 further descends to the position of the exhaust port, the exhaust process starts, and the tumble movement formed during the combustion process is beneficial to the exhaust gas discharge and improves the scavenging efficiency of the engine.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (6)

1. a swirling spray tumble combustion system for an opposed piston compression ignition engine, characterized in that: comprising opposed piston, fuel injector, combustion chamber, cylinder liner, swirl chamber and guide screen, the inner cylinder liner is installed opposite Piston, a combustion chamber is formed in the middle of the opposite piston, swirl chambers are installed symmetrically on both sides of the cylinder liner, each swirl chamber is communicated with a guide screen, and the tangential direction of the outlet of the guide screen matches the shape of the combustion chamber. An injector is installed inside the flow chamber. 2 . The swirling spray tumble combustion system for an opposed-piston compression ignition engine according to claim 1 , wherein the swirling chamber has a shape close to a sphere and is located near the top dead center of the engine. 3 . 3 . The swirling spray tumble combustion system for an opposed-piston compression ignition engine according to claim 1 , wherein the guide screen is in a tapered streamline shape from the inlet to the outlet. 4 . 4 . The swirling spray tumble combustion system for an opposed-piston compression ignition engine according to claim 1 , wherein the combustion chamber is a half-willow type. 5 . 5 . The swirling spray tumble combustion system for an opposed-piston compression ignition engine according to claim 1 , wherein the opposed pistons are of asymmetric structure and are arranged opposite to each other. 6 . 6. A swirling spray tumble combustion system for an opposed piston compression ignition engine according to claim 4, wherein: near the top dead center of the engine, the semi-willow-shaped combustion chambers on both sides form an elliptical-like combustion room.

Images