A combustion chamber for an opposed-piston engine

Abstract

This invention relates to the field of engine technology and discloses a combustion chamber suitable for opposed piston engines, comprising a cylinder block, an intake piston, an exhaust piston, a fuel injector, and a spark plug. The intake and exhaust pistons are respectively disposed at both ends of the cylinder block and together with the inner wall of the cylinder block to form the combustion chamber. The fuel injector sprays fuel jets towards the intake and exhaust pistons, respectively, and the fuel jets sprayed towards the intake and exhaust pistons are asymmetrically distributed with reference to the central cross-section of the cylinder block. A first guide groove is formed on the end face of the intake piston facing the combustion chamber, and a first fragmentation part is arranged around the inner side of the first guide groove. Multiple second guide grooves are formed on the end face of the exhaust piston facing the combustion chamber, and a second fragmentation part is arranged in each second guide groove. This invention not only promotes the rapid fragmentation of the fuel jet and guides it to the center of the combustion chamber, but also promotes the diffusion and mixing of fuel and air, achieving rapid and stable combustion.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and in particular to a combustion chamber suitable for opposed piston engines. Background Technology

[0002] A range-extended electric vehicle (REEV) is an electric vehicle that can achieve all its power performance in pure electric mode. When the onboard rechargeable energy storage system cannot meet the required driving range, an onboard auxiliary power supply device is activated to provide power to the drive system, thereby extending the driving range. This auxiliary power supply device has no driveshaft (or belt) connection to the drive system, meaning that REEVs can be driven purely on electric power and can also be charged online, significantly increasing the driving range. The design and development of the range extender is particularly important. The opposed piston engine, due to its small size, high power density, and compact structure, is of great significance as a range extender for REEVs.

[0003] The shape of the piston top surface of an opposed piston engine has a significant impact on the scavenging process, air-fuel mixing, flame propagation, combustion performance, and working efficiency of the range extender. The top surface shapes of the exhaust piston and intake piston of existing opposed piston engines are basically the same, resulting in poor air-fuel mixing uniformity and a large heat load on the exhaust piston, leading to poor combustion performance.

[0004] Therefore, how to provide a combustion chamber that provides uniform oil-gas mixing and reduces the thermal load on the exhaust piston end, suitable for opposed piston engines, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a combustion chamber suitable for opposed piston engines to solve the problems of poor air-fuel mixing uniformity and high thermal load on the exhaust piston in existing opposed piston engines, which leads to poor combustion performance.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] On one hand, the present invention provides a combustion chamber suitable for an opposed piston engine, including a cylinder block, an intake piston, an exhaust piston, a fuel injector, and a spark plug. The intake piston and the exhaust piston are respectively disposed at both ends of the cylinder block and together with the inner wall of the cylinder block to form a combustion chamber. The fuel injector injects fuel jets toward the intake piston and the exhaust piston respectively, and the fuel jets injected toward the intake piston and the exhaust piston are asymmetrically distributed with the central cross-section of the cylinder block as the reference plane.

[0008] The end face of the intake piston facing the combustion chamber is provided with a first flow guiding groove, and a first crushing portion is disposed around the inner side of the first flow guiding groove. The end face of the exhaust piston facing the combustion chamber is provided with a plurality of second flow guiding grooves, and a second crushing portion is disposed in each of the second flow guiding grooves.

[0009] Preferably, a plurality of intake side spray holes and a plurality of exhaust side spray holes are provided at the end of the fuel injector. The fuel injector sprays a first fuel bundle toward the first crushing portion through the intake side spray holes, and the fuel injector sprays a second fuel bundle toward the second crushing portion through the exhaust side spray holes;

[0010] The angles of the plurality of intake side spray holes relative to the central cross-section of the cylinder block are asymmetrically distributed with respect to the angles of the plurality of exhaust side spray holes relative to the central cross-section of the cylinder block, so that the first fuel bundle and the second fuel bundle are asymmetrically distributed relative to the central cross-section of the cylinder block.

[0011] Preferably, a plurality of the second flow guiding grooves are provided, and the second crushing portions are arranged along the axial direction of the second flow guiding grooves;

[0012] The distribution of the plurality of second crushing portions corresponds to the direction of the exhaust side spray holes, so that the second fuel bundles sprayed out by the plurality of exhaust side spray holes are atomized after being sprayed onto the second crushing portions, and the fuel spray obtained after atomization is guided to the center of the combustion chamber through the second flow guiding grooves.

[0013] Preferably, the number of the second flow guiding grooves is three, the second crushing portions are arranged along the axial direction of the second flow guiding grooves, and the three second crushing portions are distributed in a "one" shape.

[0014] Preferably, the included angle between the second crushing portion at the middle position and any one of the second crushing portions on its two sides is 30-60°.

[0015] Preferably, flow guiding portions are provided at both ends of the second flow guiding grooves to guide the fuel spray obtained after atomizing the plurality of second fuel bundles through the second crushing portions to the center of the combustion chamber through the flow guiding portions.

[0016] Preferably, the first crushing portion corresponds to the direction of the intake side spray holes, so that the first fuel bundles sprayed out by the plurality of intake side spray holes are atomized after being sprayed onto the first crushing portion, and the fuel spray obtained after atomization is split to the first flow guiding groove and the center of the combustion chamber.

[0017] Preferably, the distance from the second crushing portion to the end face of the exhaust piston is less than the distance from the first crushing portion to the end face of the intake piston.

[0018] Preferably, both the fuel injector and the spark plug are mounted on the cylinder wall, and both the fuel injector and the spark plug are located on the center surface of the cylinder, with the fuel injector and the spark plug forming an angle of 0-180°.

[0019] The intake piston and the exhaust piston are both provided with injector clearance recesses and spark plug clearance recesses on their opposite end faces.

[0020] On the other hand, the present invention also provides an opposed piston engine employing any of the combustion chambers described above.

[0021] This invention provides a combustion chamber suitable for opposed piston engines, which has the following advantages compared with the prior art:

[0022] The fuel jet direction of this invention presents an asymmetrical multi-fuel jet injection on the intake piston side and the exhaust piston side, which can greatly improve the uniformity of fuel-air mixing. Multiple fuel jets on the intake side are sprayed onto the first breaking part of the intake piston, which can force the fuel to break up and split, promoting the mixing of fuel and air. Multiple fuel jets on the exhaust side are sprayed onto the second breaking part of the exhaust piston, which breaks up the fuel and induces it to the combustion chamber for further mixing with air. This greatly reduces the possibility of fuel being directly sprayed onto the cylinder wall, achieving rapid temperature combustion.

[0023] During the movement of the intake piston and exhaust piston toward the center, the exhaust piston's top surface has a shallow ridge structure, which can compress the fuel flame into the first guide groove of the intake piston, thereby reducing the thermal load on the exhaust piston to a certain extent. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the combustion chamber structure according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the intake piston structure according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the exhaust piston structure according to an embodiment of the present invention;

[0028] Figure 4 This is a cross-sectional schematic diagram of the intake piston according to an embodiment of the present invention;

[0029] Figure 5This is a cross-sectional schematic diagram of the exhaust piston according to an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the spray landing point on the air intake side according to an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the spray landing point on the exhaust side in an embodiment of the present invention.

[0032] In the diagram:

[0033] 100-Cylinder block, 110-Intake port, 120-Exhaust port, 200-Intake piston, 210-First guide channel, 220-First crushing section, 300-Exhaust piston, 400-Injector, 410-Injector clearance, 500-Spark plug, 510-Spark plug clearance, 600-Combustion chamber, 610-Second guide channel, 620-Second crushing section, 630-Guide section, 710-First fuel jet, 720-Second fuel jet. Detailed Implementation

[0034] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0035] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0036] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0037] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0038] like Figure 1 As shown, the present invention provides a combustion chamber 600 suitable for an opposed piston engine, including a cylinder block 100, an intake piston 200, an exhaust piston 300, a fuel injector 400, and a spark plug 500. The intake piston 200 and the exhaust piston 300 are respectively disposed at both ends of the cylinder block 100 and together with the inner wall of the cylinder block 100 to form the combustion chamber 600. The fuel injector 400 and the spark plug 500 are both installed on the wall of the cylinder block 100, and the fuel injector 400 and the spark plug 500 are both located on the center surface of the cylinder block 100. The fuel injector 400 and the spark plug 500 form an angle of 0-180°, such as 30°, 90°, 180°, etc.

[0039] Furthermore, the intake piston 200 is located on the side of the cylinder intake port 110, and the exhaust piston 300 is located on the side of the cylinder exhaust port 120. The intake piston 200 and the exhaust piston 300 have the same diameter, for example, 60-100mm. The intake port 110 is used to input pressurized air, and the exhaust port 120 is used to discharge high-temperature and high-pressure gas after the working fluid in the range extender is burned.

[0040] like Figure 2 , Figure 3 As shown, in some embodiments of the present invention, the end faces of the intake piston 200 and the exhaust piston 300 are provided with injector clearance pits 410 and spark plug clearance pits 510. Preferably, the injector clearance pits 410 and spark plug clearance pits 510 on the end face of the intake piston 200 and the injector clearance pits 410 and spark plug clearance pits 510 on the end face of the exhaust piston 300 are symmetrically arranged and have the same shape, so as to avoid interference when the intake piston 200 and the exhaust piston 300 are compressed to the center.

[0041] In some embodiments of the present invention, the fuel injector 400 injects fuel jets toward the intake piston 200 and the exhaust piston 300 respectively, and the fuel jets injected toward the intake piston 200 and the exhaust piston 300 are asymmetrically distributed with the central cross-section of the cylinder block 100 as the reference plane.

[0042] Furthermore, such as Figure 2 As shown, the intake piston 200 has a first guide groove 210 on its end face facing the combustion chamber 600, and a first breaker 220 is arranged around the inner side of the first guide groove 210; as Figure 3 As shown, the exhaust piston 300 has a plurality of second guide grooves 610 on its end face facing the combustion chamber 600, and each second guide groove 610 is provided with a second crushing part 620.

[0043] In this invention, the intake-side fuel jet and the exhaust-side fuel jet are asymmetrically distributed with the central cross-section of the cylinder block 100 as the reference plane. Correspondingly, the end faces of the intake piston 200 and the exhaust piston 300 are also asymmetrically distributed, that is, the end faces of the intake piston 200 and the exhaust piston 300 have different shapes, forming combustion chambers 600 with different structures at both ends. This can promote the rapid breakup of the fuel jet and guide the broken fuel spray to the center of the combustion chamber 600, promoting the mixing of fuel and air and achieving rapid and stable combustion.

[0044] In some embodiments of the present invention, the injector 400 is provided with a plurality of intake-side nozzles and a plurality of exhaust-side nozzles at its end. The injector 400 injects a plurality of first fuel jets 710 into the first breaker 220 through the intake-side nozzles, and injects a plurality of second fuel jets 720 into the second breaker 620 through the exhaust-side nozzles. The angles of the plurality of intake-side nozzles relative to the central cross-section of the cylinder block 100 and the angles of the plurality of exhaust-side nozzles relative to the central cross-section of the cylinder block 100 are asymmetrically distributed, so that the first fuel jets 710 and the second fuel jets 720 are asymmetrically distributed relative to the central cross-section of the cylinder block 100.

[0045] The injector 400 of the present invention has an asymmetrical intake side nozzle and an exhaust side nozzle at its end. The injected fuel jets develop towards the pistons on both sides, forming an intake side fuel jet and an exhaust side fuel jet. The direction of the fuel jet matches the structure of the breaking part at the end of the combustion chamber 600, that is, the landing point of the fuel jet is on the first breaking part 220 and the second breaking part 620, so that the fuel jet is broken into fuel spray, making the subsequent combustion more uniform and complete.

[0046] In some embodiments of the present invention, there are multiple second guide channels 610, and the second fragmentation section 620 is arranged along the axial direction of the second guide channel 610; the distribution of the multiple second fragmentation sections 620 corresponds to the direction of the exhaust side nozzles, so that the second fuel jet 720 injected from the multiple exhaust side nozzles is atomized after being injected into the second fragmentation section 620, and the atomized fuel spray is guided to the center of the combustion chamber 600 through the second guide channel 610.

[0047] Furthermore, both ends of the second guide channel 610 are provided with guide sections 630 to guide the fuel spray obtained after the multiple second fuel jets 720 are atomized by the second breaker section 620 to the center of the combustion chamber 600 through the guide sections 630.

[0048] The angle of the second fragmentation part 620 is precisely matched with the fuel spray direction on the exhaust side, that is, the landing point of the fuel spray on the exhaust side is on the second fragmentation part 620. The second fragmentation part 620 can forcibly break up multiple fuel sprays ejected in the exhaust side direction and guide them to the center of the cylinder through the diversion part 630. Preferably, the shape of the diversion part 630 can be hemispherical, semi-ellipsoidal or in the shape of an inclined plate, as long as the diversion effect can be achieved, and it can be selected according to the actual situation. The setting of the diversion part 630 can not only promote the mixing of fuel and air, but also effectively avoid lubrication problems caused by oil dilution.

[0049] In some embodiments of the present invention, the number of the second diversion grooves 610 is three. The second fragmentation part 620 is arranged along the axial direction of the second diversion grooves 610, and the three second fragmentation parts 620 are distributed in a "one" shape. The included angle between the second fragmentation part 620 at the middle position and any one of the second fragmentation parts 620 on its two sides is 30-60°.

[0050] Furthermore, corresponding to the number of the second diversion grooves 610, the number of the second fuel sprays 720 ejected from the exhaust side spray holes is three. As Figure 7 shown, the direction of any one of the second fuel sprays 720 corresponds to one second fragmentation part 620, that is, the landing point of each second fuel spray 720 corresponds to a different second fragmentation part 620, so as to break up and atomize the second fuel spray 720 through the second fragmentation part 620, and the obtained fuel spray is guided to the center of the combustion chamber 600 through the diversion part 630.

[0051] By limiting the arrangement form of the second diversion grooves 610, the fuel sprays ejected from the exhaust side spray holes of the injector 400 can fall more evenly on the end face of the exhaust piston 300, which can not only make the mixing of fuel and air more uniform, but also make the end face of the exhaust piston 300 receive heat more evenly, avoiding a large thermal load at a single position. It should be noted that the above is only one of the number and distribution methods of the second diversion grooves 610, and the specific distribution can be determined according to the actual situation. When arranging the second diversion grooves 610, pay attention to the consistency between the fuel spray direction and the angle of the second fragmentation part 620, that is, ensure that the landing point of the fuel spray is on the second fragmentation part 620.

[0052] In some embodiments of the present invention, the first fragmentation part 220 corresponds to the intake side spray hole direction, that is, the first fragmentation part 220 corresponds to the directions of multiple first fuel sprays 710 ejected from the intake side spray holes, so that the multiple first fuel sprays 710 ejected from the intake side spray holes are atomized after falling on the first fragmentation part 220, and the atomized fuel spray is split to the first diversion groove 210 and the center of the combustion chamber 600.

[0053] Furthermore, as Figure 6As shown, the number of the first fuel jet 710 can be two, three or more. It is not required that the number of the first fuel jet 710 be the same or symmetrical with that of the second fuel jet 720. It is only necessary to ensure that the landing point of the first fuel jet 710 is in the first breaking section 220. The first breaking section 220 can not only break the fuel jet, but also guide and divert the flow.

[0054] In this invention, the first breaking section 220 divides the first guide groove 210 on the intake piston 200 into two interconnected parts. The inner diameter of the first guide groove 210 near the end face of the intake piston 200 is larger than the inner diameter of the first guide groove 210 at the other end. The fuel jet injected from the intake side nozzle of the injector 400 falls into the first breaking section 220 and is broken into fuel spray. Then, under the action of the first breaking section 220, the fuel spray is split, with one part flowing into the interior of the first guide groove 210 and the other part being guided to the center of the combustion chamber 600, thus promoting the mixing of fuel and air on the intake side.

[0055] In some embodiments of the present invention, the distance from the second crushing part 620 to the end face of the exhaust piston 300 is less than the distance from the first crushing part 220 to the end face of the intake piston 200.

[0056] In some specific embodiments of the present invention, the first crushing part 220 and the second crushing part 620 are both arranged in the shape of ridges. Specifically, the first crushing part 220 can be a waistline ridge, which is arranged around the first guide groove 210. The second crushing part 620 can be a guide ridge, which is arranged axially in the second guide groove 610. The distance from the guide ridge to the end face of the exhaust piston 300 is less than the distance from the waistline ridge to the end face of the intake piston 200.

[0057] The piston end face of the exhaust piston 300 of the present invention is designed to be shallow. Therefore, when the top surfaces of the intake piston 200 and the exhaust piston 300 are compressed to the center of the cylinder, more of the flame can burn in the guide groove of the intake piston 200, which can effectively reduce the heat load on the exhaust side piston and avoid the phenomenon of excessive heat on the exhaust side piston 300 caused by excessively high temperature during combustion.

[0058] In other embodiments of the present invention, an opposed piston engine employing the combustion chamber of any of the above embodiments is also provided. Since the engine includes the combustion chamber of the present invention, the engine has all the aforementioned features and effects of the combustion chamber, which will not be repeated here. Furthermore, the opposed piston engine including the combustion chamber can be applied to vehicles to improve the fuel efficiency of vehicle engines.

[0059] In summary, the combustion chamber of the present invention, applicable to opposed piston engines, features an asymmetrical arrangement of fuel jets on the intake and exhaust sides. The asymmetrical combustion chamber shape is designed according to the direction of the fuel jets. This not only promotes rapid fuel jet fragmentation and guides the fuel jets to the center of the combustion chamber, but also facilitates the diffusion and mixing of fuel with air within the first guide groove at the piston end and the space enclosed by the pistons on both sides, achieving rapid and stable combustion. Furthermore, by employing a piston end structure design with a deep-pit first fragmentation section and a shallow-pit second fragmentation section, the phenomenon of excessively high exhaust piston temperature during combustion can be avoided.

[0060] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A combustion chamber suitable for an opposed piston engine, comprising a cylinder block, an intake piston, an exhaust piston, a fuel injector, and a spark plug, wherein the intake piston and the exhaust piston are respectively disposed at both ends of the cylinder block and together with the inner wall of the cylinder block form a combustion chamber, characterized in that... , The fuel injector injects fuel beams towards the intake piston and the exhaust piston respectively, and the fuel beams injected towards the intake piston and the exhaust piston are asymmetrically distributed with the central cross-section of the cylinder block as the reference plane; The end face of the intake piston facing the combustion chamber is provided with a first flow guiding groove, and a first fragmentation part is arranged around the inner side of the first flow guiding groove. The end face of the exhaust piston facing the combustion chamber is provided with a plurality of second flow guiding grooves, and a second fragmentation part is arranged in each of the second flow guiding grooves; The end of the fuel injector is provided with a plurality of intake-side spray holes and a plurality of exhaust-side spray holes. The fuel injector injects a first fuel beam towards the first fragmentation part through the intake-side spray holes, and the fuel injector injects a second fuel beam towards the second fragmentation part through the exhaust-side spray holes; The second fragmentation part is arranged along the axial direction of the second flow guiding groove; The distribution of the plurality of second fragmentation parts corresponds to the direction of the exhaust-side spray holes, so that the second fuel beams ejected from the plurality of exhaust-side spray holes are atomized after being ejected to the second fragmentation parts, and the fuel spray obtained after atomization is guided to the center of the combustion chamber through the second flow guiding groove.

2. The combustion chamber applicable to an opposed-piston engine according to claim 1, wherein The angles of the plurality of intake-side spray holes relative to the central cross-section of the cylinder block and the angles of the plurality of exhaust-side spray holes relative to the central cross-section of the cylinder block are asymmetrically distributed, so that the first fuel beam and the second fuel beam are asymmetrically distributed relative to the central cross-section of the cylinder block.

3. The combustion chamber suitable for use in an opposed-piston engine according to claim 1, characterized by, The number of the second flow guiding grooves is three, the second fragmentation part is arranged along the axial direction of the second flow guiding groove, and the three second fragmentation parts are distributed in a "one" shape.

4. The combustion chamber suitable for use in an opposed-piston engine according to claim 3, characterized in that, The included angle between the second fragmentation part located in the middle position and any one of the second fragmentation parts on its two sides is 30-60°; 5. The combustion chamber suitable for use in an opposed-piston engine according to claim 1, characterized by, Flow guiding parts are arranged at both ends of the second flow guiding groove to guide the fuel spray obtained after atomizing the plurality of second fuel beams through the second fragmentation part to the center of the combustion chamber through the flow guiding parts.

6. The combustion chamber suitable for use in an opposed-piston engine according to claim 1, characterized by, The first fragmentation part corresponds to the direction of the intake-side spray holes, so that the first fuel beams ejected from the plurality of intake-side spray holes are atomized after being ejected to the first fragmentation part, and the fuel spray obtained after atomization is split to the first flow guiding groove and the center of the combustion chamber.

7. A combustion chamber suitable for use in an opposed-piston engine according to any one of claims 1 - 6, characterised in that The distance from the second fragmentation part to the end face of the exhaust piston is less than the distance from the first fragmentation part to the end face of the intake piston.

8. The combustion chamber for an opposed piston engine according to claim 7, characterized in that, The fuel injector and the spark plug are both installed on the cylinder block wall, and the fuel injector and the spark plug are both located on the central plane of the cylinder block, and the included angle between the fuel injector and the spark plug is 0-180°; The end faces of the intake piston and the exhaust piston opposite to each other are provided with fuel injector avoidance pits and spark plug avoidance pits. An opposed-piston engine adopting the combustion chamber according to any one of claims 1-8.

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