CN114961975A

CN114961975A - Engine pre-combustion device and engine pre-combustion system

Info

Publication number: CN114961975A
Application number: CN202210639140.8A
Authority: CN
Inventors: 王浒; 尧志峰; 王洁明; 陈勇; 宋腾达; 郑尊清; 尧命发
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2022-05-31
Filing date: 2022-05-31
Publication date: 2022-08-30

Abstract

The invention provides an engine precombustion device, comprising: a housing; the ignition mechanism is arranged inside the shell; the pre-combustion part is connected with one end of the shell, a pre-combustion cavity is formed inside the pre-combustion part, and the ignition end of the ignition mechanism extends into the pre-combustion cavity; and a fuel gas flow passage in communication with the prechamber for conveying a combustion medium; wherein the area of the radial cross section of the prechamber gradually decreases in a direction away from the ignition mechanism, so that the inner surface of the prechamber reflects the combustion medium conveyed into the prechamber to promote thorough mixing of the combustion medium. The invention further provides an engine pre-combustion system comprising the engine pre-combustion device.

Description

Engine pre-combustion device and engine pre-combustion system

Technical Field

The invention relates to the technical field of engines, in particular to an engine pre-combustion device and an engine pre-combustion system.

Background

In recent years, the climate and environmental problems are concerned, the emission of greenhouse gases is reduced slowly, the transportation of vehicles is one of the main ways of emitting greenhouse gases, and the emission reduction becomes an important direction for the research and development of engines.

The lean combustion can reduce the emission of nitrogen oxides and simultaneously can keep the high efficiency of the engine, and because the combustion temperature of the lean combustion is lower, the emission of the nitrogen oxides is effectively reduced to reach the level close to zero; under the medium-load working condition, the lean combustion can reduce the exhaust emission and simultaneously can keep lower oil consumption, and higher efficiency is obtained. However, the lower combustion speed of lean combustion makes the combustion process longer and incomplete, resulting in unstable engine combustion.

The pre-chamber injection ignition approach may extend the lean limit because pre-chamber injection ignition may create multiple ignition points, increasing the likelihood that a lean mixture will ignite. However, the prior pre-combustion chamber type combustion chamber has low oil injection pressure, and the premixing effect of the combustion medium mixed by air and fuel in the pre-combustion chamber is poor, so that smooth ignition in the pre-combustion chamber of the engine is hindered. Meanwhile, the combustion speed of the combustion medium in the pre-combustion chamber is low, so that the power is reduced, and the overall thermal efficiency is not high. Therefore, it is desirable to design a pre-combustion device for an engine capable of increasing the combustion speed of the pre-combustion chamber.

Disclosure of Invention

In order to overcome at least one of the technical problems, embodiments of the present invention provide an engine pre-combustion apparatus and an engine pre-combustion system, in which by changing a radial cross-sectional area of a pre-combustion chamber, a shock wave generated by a flame is reflected and superimposed in the pre-combustion chamber, so as to promote combustion in the pre-combustion chamber and improve ignition stability of an engine.

The invention provides an engine precombustion device, comprising: a housing; the ignition mechanism is arranged inside the shell; the pre-combustion part is connected with one end of the shell, a pre-combustion cavity is formed inside the pre-combustion part, and the ignition end of the ignition mechanism extends into the pre-combustion cavity; and a fuel gas flow channel communicated with the precombustion chamber to convey a combustion medium; wherein the area of the radial cross section of the prechamber gradually decreases in a direction away from the ignition mechanism, so that the inner surface of the prechamber reflects the combustion medium conveyed into the prechamber to promote thorough mixing of the combustion medium.

In a possible embodiment, the ignition end extends from the end of the prechamber with the larger cross-section into the prechamber.

In a possible embodiment, the prechamber is a stepped or spiral stepped bore.

In a possible implementation manner, the engine pre-combustion apparatus further includes: the injection part is connected to one end, far away from the ignition mechanism, of the pre-burning part, and at least one injection hole is formed in one end, far away from the pre-burning part, of the injection part.

In a possible embodiment, the interior of the injection part forms a gradually narrowing injection chamber, the larger end of which is connected to the prechamber.

In one possible embodiment, the injection chamber is a stepped bore or a spiral stepped bore.

In one possible embodiment, the number of the injection holes is at least two, and the injection holes are evenly distributed around the center line of the injection cavity.

In one possible embodiment, the ignition mechanism is a spark plug, a portion of the spark plug remote from the ignition end is disposed inside the housing, and the ignition end of the spark plug extends outside the housing.

In a possible embodiment, the gas flow channel is disposed through a side wall of the housing, and the gas flow channel communicates the prechamber with a combustion medium conduit.

The embodiment of the invention also provides an engine precombustion system, which comprises: an engine pre-combustion device; one end of the combustion medium pipeline is communicated with the engine pre-combustion device; and the premixing device is communicated with the other end of the combustion medium pipeline and is used for premixing the combustion medium.

According to the engine pre-combustion device and the engine pre-combustion system provided by the embodiment of the invention, by changing the radial cross-sectional area of the pre-combustion cavity, the reflection of shock waves generated by flame in the pre-combustion chamber is overlapped, combustion media are fully mixed, the combustion in the pre-combustion chamber is promoted, and the ignition stability of the engine is improved.

Drawings

FIG. 1 is a schematic illustration of an engine pre-combustion apparatus according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of an engine pre-combustion apparatus according to an embodiment of the present invention;

FIG. 3 is a top view of a pre-combustion portion and an injection portion in accordance with an embodiment of the present invention.

[ notation in the drawings ]

1-a premixing device;

2-a combustion medium line;

3-an engine pre-combustion device;

31-a housing;

32-an ignition mechanism;

33-a pre-combustion section;

34-a gas flow channel;

35-a spray section;

351-jet hole;

36-a cover plate;

37-a compression section.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It is to be understood that this description is made only by way of example and not as a limitation on the scope of the invention. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention. It may be evident, however, that one or more embodiments may be practiced without these specific details. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

According to the engine pre-combustion device and the engine pre-combustion system provided by the embodiment of the invention, by changing the radial cross-sectional area of the pre-combustion cavity, the reflection of shock waves generated by flame in the pre-combustion chamber is superposed, the combustion in the pre-combustion chamber is promoted, and the ignition stability of the engine is improved.

According to the present general inventive concept, there is provided an engine pre-combustion apparatus including: a housing; the ignition mechanism is arranged inside the shell; the pre-combustion part is connected with one end of the shell, a pre-combustion cavity is formed inside the pre-combustion part, and the ignition end of the ignition mechanism extends into the pre-combustion cavity; and a fuel gas flow passage in communication with the prechamber for conveying a combustion medium; wherein the area of the radial cross section of the prechamber gradually decreases in a direction away from the ignition mechanism, so that the inner surface of the prechamber reflects the combustion medium conveyed into the prechamber to promote thorough mixing of the combustion medium.

FIG. 1 is a schematic view of an engine pre-combustion apparatus according to an embodiment of the present invention.

As shown in fig. 1, in some embodiments, the engine pre-combustion system comprises an engine pre-combustion device 3 of the present invention, a combustion medium conduit 2 communicating with the engine pre-combustion device 3 at one end, and a premixing device 1 communicating with the other end of the combustion medium conduit 2, the premixing device 1 being configured to premix the combustion medium.

In some embodiments of the present invention, the premixing device 1 includes a first air inlet end, a second air inlet end disposed on the same side of the first air inlet end, and a premixing air outlet end disposed on the opposite side of the first air inlet end and the second air inlet end. The premixed gas outlet end is communicated with one end of the combustion medium pipeline 2. The gas enters the premixing device 1 from the first gas inlet end, the air enters the premixing device 1 from the second gas inlet end, and the mixed gas after premixing enters the combustion medium pipeline 2 from the premixing gas outlet end and then enters the engine pre-combustion device 3.

FIG. 2 is a cross-sectional view of an engine pre-combustion apparatus according to an embodiment of the present invention.

As shown in fig. 2, in some embodiments, an engine pre-combustion apparatus includes: a housing 31; an ignition mechanism 32 provided inside the housing 31; a precombustion part 33 connected with one end of the shell 31, a precombustion cavity is formed inside the precombustion part 33, and the ignition end of the ignition mechanism 32 extends into the precombustion cavity; and a gas flow passage 34 communicating with the prechamber for conveying a combustion medium. Wherein the area of the radial cross section of the prechamber decreases gradually in a direction away from the ignition mechanism 32, so that the inner surface of the prechamber reflects the combustion medium conveyed into the prechamber to promote thorough mixing of the combustion medium.

In some embodiments of the present invention, the housing 31 is tubular and the firing end of the firing mechanism 32 extends out of an end of the housing 31. The end of the shell 31, which penetrates out of the ignition end, is provided with a threaded interface, and is in threaded connection with one end of the pre-combustion part 33. In some embodiments, a cover plate 36 is disposed at an end of the housing 31 away from the firing end of the ignition mechanism 32, and a pressing portion 37 is disposed at a side of the cover plate 36 away from the housing 31. The cover plate 36 is connected to the housing 31 by pressing with the pressing portion, thereby sealing the housing 31.

In some embodiments of the present invention, the ignition mechanism 32 is a spark plug, and the portion of the spark plug away from the firing end is disposed inside the housing 31, and the firing end of the spark plug extends outside the housing 31. In some embodiments, the electrodes of the spark plug extend into the prechamber.

In some embodiments of the present invention, a gas flow passage 34 is provided through the side wall of the housing 31, and the gas flow passage 34 communicates the prechamber with the combustion medium conduit 2. In some embodiments, the gas flow passage 34 is a communication conduit provided in the side wall, communicating the prechamber with the premixed gas outlet end of the combustion medium conduit 2, so that the mixed gas enters the prechamber interior through the gas flow passage 34. The fuel gas flow passage 34 may also be a pipe arranged outside the housing 31, and an external pipe communicates the prechamber and the combustion medium pipe 2, so that the mixed gas enters the prechamber.

In some embodiments of the invention, the firing end extends from the larger cross-sectional end of the prechamber into the prechamber.

With continued reference to FIG. 2, in some embodiments, the area of the radial cross-section of the prechamber connected to the housing 31 is largest, and gradually decreases in the direction away from the housing 31. The change of the area of the radial cross section of the precombustion cavity enables shock waves generated after the mixed gas is ignited to be reflected and superposed for many times in the precombustion cavity, and further mixing of fuel oil and air in the mixed gas is promoted.

With continued reference to FIG. 2, in some embodiments, the prechamber is a multi-step or spiral step bore.

In some embodiments of the invention, the prechamber is a multi-stage stepped bore with a decreasing radial cross-sectional area. In other embodiments, the prechamber is a helical stepped bore of decreasing radial cross-sectional area.

In some embodiments of the present invention, the engine pre-combustion apparatus 3 further includes: and an injection part 35 connected to an end of the precombustion part 33 remote from the ignition mechanism 32, wherein at least one injection hole 351 is provided at an end of the injection part 35 remote from the precombustion part 33. The mixture enters the jet chamber from the prechamber and is directed out of the engine prechamber 3 through the jet holes 351.

In some embodiments, the injection portion 35 has an injection cavity therein, and the maximum area of the radial cross section of the injection cavity is equal to and in communication with the minimum area of the radial cross section of the prechamber. In some embodiments, the injection holes 351 have a diameter of 2-4mm and are disposed on the end surface furthest from the pre-combustion portion 33.

In some embodiments of the present invention, there are at least two spray holes 351 that are evenly distributed about the centerline of the spray chamber. In some embodiments, the number of injection holes 351 is 2-6, and is disposed at an end of the injection portion 35 remote from the pre-combustion portion 33.

In some embodiments of the invention the interior of the injection part 35 forms a gradually narrowing injection chamber, the larger end of which is connected to the pre-combustion part 33. In some embodiments, the axial cross-section of the spray chamber is tapered or trapezoidal. The flow rate of the mixed gas is increased by the gradual decrease of the area of the radial section of the injection chamber. Further, when the mixture gas is ignited, the propagation speed of the flame is increased.

With continued reference to FIG. 2, in some embodiments, the spray chamber is a multi-step stepped bore or a spiral stepped bore. In some embodiments, the mixed gas descends in a spiral direction, further increasing the flow rate of the mixed gas.

In some embodiments of the invention, the injection chamber is a multi-step stepped bore of decreasing radial cross-sectional area. In other embodiments, the ejection chamber is a helical stepped bore of decreasing radial cross-sectional area.

As shown in FIG. 2, in some embodiments, the prechamber and the injection chamber are both stepped bores of decreasing radial cross-sectional area.

When the engine pre-combustion system of the embodiment of the invention works, the ignition mechanism 32 ignites the mixed gas in the pre-combustion part 33 to form flame. Shock waves accompanying the ignition of the gas mixture are reflected by the inner surface of the precombustion portion 33, and the reflection forms multi-stage reflection due to the change of the inner surface of the precombustion portion 33. The multistage reflected shock waves act on the flame surface at the same time, so that the flame turbulence in the pre-combustion part 33 is enhanced, and the mixing uniformity of the mixed gas is further improved. The flame propagates from the precombustion portion 33 to the injection cavity of the injection portion 35, and the propagation speed of the flame is further increased by contraction of the injection cavity, and the flame is ejected from the engine precombustion device through the ejection hole 351.

According to the engine pre-combustion device and the engine pre-combustion system provided by the embodiment of the invention, by changing the radial cross-sectional area of the pre-combustion chamber, the reflection superposition of shock waves generated by flame in the pre-combustion chamber is realized, and after the contraction of the injection chamber, the flame speed is further improved, the combustion speed in the pre-combustion chamber is promoted, the detonation resistance and the compression ratio of an internal combustion engine are improved, and the ignition stability and the overall heat efficiency of the engine are further improved.

It should also be noted that directional terms, such as "upper", "lower", "front", "rear", "left", "right", etc., used in the embodiments are only directions referring to the drawings, and are not intended to limit the scope of the present invention. Throughout the drawings, like elements are represented by like or similar reference numerals. Conventional structures or constructions will be omitted when they may obscure the understanding of the present invention. And the shapes and sizes of the respective components in the drawings do not reflect actual sizes and proportions, but merely illustrate contents of the embodiments of the present invention.

The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify a corresponding element does not by itself connote any ordinal number of the element or any ordering of one element from another or the order of manufacture, and the use of the ordinal numbers is only used to distinguish one element having a certain name from another element having a same name.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An engine pre-combustion apparatus comprising:

a housing (31);

an ignition mechanism (32) provided inside the housing (31);

a pre-combustion part (33) connected with one end of the shell (31), a pre-combustion cavity is formed inside the pre-combustion part (33), and the ignition end of the ignition mechanism (32) extends into the pre-combustion cavity; and

a gas flow passage (34) in communication with the prechamber for conveying a combustion medium;

wherein the area of the radial cross section of the prechamber decreases gradually in a direction away from the ignition mechanism (32) such that the inner surface of the prechamber reflects the combustion medium conveyed into the prechamber to promote thorough mixing of the combustion medium.

2. The engine precombustor of claim 1, wherein the firing end extends from the larger cross-sectional end of the precombustor into the precombustor.

3. The engine precombustor of claim 2, wherein the precombustor is a multi-step stepped bore or a spiral stepped bore.

4. The engine pre-combustion apparatus of claim 1, further comprising:

and the injection part (35) is connected to one end, far away from the ignition mechanism (32), of the pre-combustion part (33), and at least one injection hole (351) is arranged at one end, far away from the pre-combustion part (33), of the injection part (35).

5. An engine pre-combustion arrangement according to claim 4, wherein the interior of the injection part (35) forms a gradually narrowing injection chamber, the larger end of which is connected to the pre-combustion part (33).

6. The engine pre-combustion apparatus of claim 5, wherein the injection cavity is a multi-step stepped bore or a spiral stepped bore.

7. An engine pre-combustion arrangement according to claim 4, wherein the injection holes (351) are at least two and evenly distributed about a centre line of the injection chamber.

8. An engine pre-combustion arrangement according to claim 1, wherein the ignition mechanism (35) is a spark plug, a portion of the spark plug remote from a firing end of the spark plug being arranged inside the housing (31), the firing end of the spark plug extending outside the housing (31).

9. An engine pre-combustion arrangement according to claim 1, wherein the gas flow channel (34) is provided through the side wall of the housing (31), the gas flow channel (34) communicating the pre-combustion chamber with the combustion medium conduit (2).

10. An engine pre-combustion system, comprising:

an engine pre-combustion device (3) according to any of claims 1-9;

a combustion medium pipeline (2), one end of which is communicated with the engine pre-combustion device (3); and

and the premixing device (1) is communicated with the other end of the combustion medium pipeline (2) and is used for premixing the combustion medium.