Compression ignition type pre-combustion chamber structure, engine and operation method

Abstract

The present invention discloses a compression ignition type precombustion chamber structure, an engine and an operation method. The compression ignition type precombustion chamber structure comprises a precombustion body and an engine cylinder. The precombustion body is provided with a precombustion body hole of a blind hole structure. A plunger body is slidably installed in the precombustion body hole. The plunger body is connected to a plunger driving mechanism. A precombustion inner cavity is provided on the inner end surface of the plunger body. The precombustion inner cavity, the bottom surface and the side wall of the precombustion body hole together define a precombustion chamber. The side wall of the precombustion body hole is provided with an injection channel connected to a main combustion chamber. The side wall of the precombustion inner cavity is provided with an injection hole corresponding to the injection channel. When the plunger body is in an upper limit position, the injection channel directly connects the main combustion chamber and the precombustion chamber. When the plunger body is in a lower limit position, the injection hole connects the injection channel, the precombustion chamber and the main combustion chamber. The combustible mixture in the precombustion chamber is compressed and ignited. There is no need to arrange an ignition device on the precombustion chamber, thus eliminating a set of ignition devices and fuel injection devices. The structure is simple and the cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a compression ignition type pre-combustion chamber structure, an engine and an operating method. Background Art

[0002] At present, due to the requirements of energy conservation, emission reduction and fuel consumption regulations, the engine has to achieve an effective thermal efficiency of 45% or even higher. Lean combustion for various fuel engines such as gasoline, natural gas, methanol and ammonia can improve the adiabatic index of the mixture, reduce the combustion temperature and suppress knocking. It is an effective technology to achieve a thermal efficiency greater than 45%. For example, lean combustion for gasoline engines can improve fuel economy by 5%-10%, and can also reduce emissions of carbon monoxide (CO), hydrogen (H2), hydrocarbons (HC), etc. If ultra-lean combustion (lambda greater than 1.5) is used, because the air dilution degree is high and the combustion temperature is relatively low, it can improve the thermal efficiency of the gasoline engine while not causing excessive NOx emissions.

[0003] However, it is difficult for existing spark plugs to ignite ultra-lean mixtures, so ultra-lean combustion requires a high-energy ignition device to meet the use requirements. Therefore, in the research of ultra-lean combustion, pre-combustion chamber technology has received widespread attention. This technology forms a mixture in the pre-combustion chamber that can be easily ignited by a spark plug, and then the high-temperature combustion mixture after the pre-combustion chamber mixture is burned is sprayed from the pre-combustion chamber into the main combustion chamber, quickly igniting the lean mixture in the main combustion chamber. The jet ignition of the pre-combustion chamber generates multiple ignition sources in the spray area of ​​the spray hole, which can achieve a very fast combustion rate.

[0004] Obviously, the pre-combustion chamber can reduce the difficulty of ignition under lean-burn conditions, significantly increase the combustion rate, and overcome the shortcomings of slow flame propagation speed and large combustion cycle fluctuations under super lean-burn conditions. The prior art usually uses a fuel injection device in the pre-combustion chamber to inject part of the fuel into the pre-combustion chamber to form a relatively concentrated mixture in the pre-combustion chamber that is easy to be ignited by the spark plug. However, this measure has the following disadvantages: the pre-combustion chamber is small in size, and it is very difficult to arrange the fuel injection device and the spark plug reasonably. The internal mixture organization is very difficult, and the fuel concentration stability at the spark plug position is poor, resulting in increased uncertainty in flame development, large engine cycle fluctuations, and direct injection. The fuel hits the wall seriously, and is easy to coke and generate soot; after direct injection, the liquid fuel vaporizes and absorbs heat in the pre-combustion chamber, making cold start more difficult. Summary of the invention

[0005] The object of the present invention is to provide a compression ignition pre-combustion chamber structure, an engine and an operating method to solve one or more technical problems existing in the prior art and at least provide a beneficial choice or create conditions.

[0006] The technical solutions adopted to solve the above technical problems are:

[0007] First, the present invention provides a compression ignition precombustion chamber structure, which includes: a precombustion body, an engine cylinder, a main combustion chamber formed in the inner space of a piston and the engine cylinder is provided in the engine cylinder, the precombustion body is provided with a precombustion body hole of a blind hole structure, a plunger body is slidably installed in the precombustion body hole, the plunger body is connected to a plunger driving mechanism for driving the plunger body to reciprocate along the axial direction of the precombustion body hole, the inner end surface of the plunger body is provided with a precombustion inner cavity with an open cavity structure, the precombustion inner cavity, the bottom surface and the side wall of the precombustion body hole jointly define a precombustion chamber, the inner end side wall of the precombustion body hole is provided with an injection channel connected to the main combustion chamber, the side wall of the precombustion inner cavity is provided with an injection hole corresponding to the injection channel, and the plunger body has an upper limit and a lower limit during the reciprocating movement of the plunger body, the plunger body is in the upper limit position so that the injection channel directly connects the main combustion chamber and the precombustion chamber, and the plunger body is in the lower limit position so that the injection hole connects the injection channel, the precombustion chamber and the main combustion chamber.

[0008] The beneficial effect of the precombustion chamber structure provided by the present invention is: the plunger driving mechanism is used to drive the plunger body to move axially back and forth in the precombustion body hole, thereby changing the volume of the precombustion chamber, compressing the fresh mixture in the precombustion chamber, and promoting the spontaneous combustion of the fuel in the fresh mixture or a partial combustion reaction. When the plunger body is at the upper limit position of the precombustion body hole, the volume of the precombustion chamber is the largest. At this time, the injection channel directly connects the main combustion chamber and the precombustion chamber, and the main combustion chamber and the fresh mixture can enter the precombustion chamber through the injection channel; and when the plunger body is at the lower limit position of the precombustion body hole, the volume of the precombustion chamber is the smallest, and the mixture in the precombustion chamber is compressed to spontaneously ignite or In a partial combustion reaction, the injection hole connects the injection channel, the precombustion chamber and the main combustion chamber, and the high-temperature and high-pressure mixture after the reaction in the precombustion chamber enters the main combustion chamber to ignite the lean fresh mixture; when the plunger body is in other positions between the upper limit and the lower limit, the injection channel is blocked by the side wall of the precombustion cavity, and the connection between the precombustion chamber and the main combustion chamber is disconnected. The technology moves the plunger body to different positions and utilizes the side wall of the precombustion cavity to keep the precombustion chamber and the main combustion chamber connected and disconnected through the injection channel, so that the main combustion chamber mixture can enter the precombustion chamber through the injection channel, and the high-temperature mixture after combustion in the precombustion chamber can enter the main combustion chamber through the injection hole and the injection channel.

[0009] The combustible mixture in the pre-combustion chamber is compressed and ignited, and there is no need to arrange an ignition device on the pre-combustion chamber. In addition, the compression ignition significantly reduces the requirements for the organization of the mixture in the pre-combustion chamber, and there is no need to arrange a fuel injection device on the pre-combustion chamber, eliminating a set of ignition devices and fuel injection devices, with a simple structure and low cost. For fuels with high ignition energy, such as ammonia fuel, it is difficult for existing ignition devices to ignite the mixture in the pre-combustion chamber, but the compression ignition of the present invention can make the pre-combustion chamber mixture reliably self-ignite or produce a partial combustion reaction, making it possible to use this type of fuel in the engine.

[0010] As a further improvement of the above technical solution, a plurality of the injection channels are circumferentially arranged on the inner end side wall of the pre-combustion body hole, and a plurality of injection holes are provided on the side wall of the pre-combustion inner cavity whose circumferential arrangement positions are consistent with those of the injection channels.

[0011] Multiple injection channels are mainly used to increase the ignition source, because the jet ejected from each injection channel is equivalent to an ignition source. The number and arrangement of injection channels generally need to be obtained by in-cylinder combustion calculations and need to be coordinated with the in-cylinder flow.

[0012] As a further improvement of the above technical solution, the side wall of the pre-combustion body hole is provided with a first circumferential positioning portion, and the plunger body is provided with a second circumferential positioning portion that slidably cooperates with the first circumferential positioning portion.

[0013] In this solution, the second circumferential positioning portion and the first circumferential positioning portion are slidably matched to achieve circumferential positioning of the plunger body, so that during the reciprocating motion of the plunger body, the injection hole can be accurately connected to the injection channel.

[0014] As a further improvement of the above technical solution, the outer peripheral wall of the plunger body is provided with a plurality of annular grooves, the annular groove sleeve is provided with a plunger ring, and the injection hole is arranged between two adjacent annular grooves.

[0015] The plunger body in this solution is in sliding sealing contact with the side wall of the pre-combustion body hole through multiple plunger rings, thereby improving the sealing between the plunger body and the pre-combustion body hole and preventing the leakage of high-temperature and high-pressure mixed gas in the pre-combustion chamber.

[0016] As a further improvement of the above technical solution, the pre-combustion body hole is a "T"-shaped stepped structure, the pre-combustion body hole includes a large hole at the upper end and a small hole at the lower end, the plunger body is a "T"-shaped shaft structure, the plunger body includes a large head arranged in the large hole at the upper end, and a small head sleeved in the small hole at the lower end, the plunger driving mechanism includes a plunger spring, a plunger driving cam, and a plunger camshaft, the large head is flexibly connected to the step surface of the pre-combustion body hole through the plunger spring, the plunger driving cam is installed on the plunger camshaft, and the outer peripheral surface of the plunger driving cam is in contact with the top of the plunger body.

[0017] The plunger driving mechanism in this scheme drives the plunger driving cam to rotate through the plunger camshaft. The elastic force of the plunger spring causes the large end of the plunger body to press against the cam surface. The rotating plunger driving cam overcomes the elastic force of the plunger spring and causes the plunger body to reciprocate in the pre-combustion body hole, thereby realizing the change of the pre-combustion chamber volume.

[0018] As a further improvement of the above technical solution, the pre-combustion inner cavity is provided with a flow guide structure for guiding the flow of the mixed gas in the pre-combustion chamber and a reinforcing rib structure for enhancing the structural strength.

[0019] As a further improvement of the above technical solution, the wall surface, the guide and the surface of the reinforcing rib structure of the pre-combustion cavity are coated with a heat-insulating coating, which can reduce the heat transfer loss between the high-temperature mixed gas in the pre-combustion chamber and the wall surface.

[0020] As a further improvement of the above technical solution, the engine cylinder includes a cylinder block and a cylinder head, and the pre-combustion body is a part of the cylinder head.

[0021] In this solution, a part of the pre-combustion body is directly processed on the cylinder head, thereby reducing the number of engine parts. The pre-combustion body hole and the injection channel are directly processed on the cylinder head, thereby reducing assembly errors.

[0022] The present invention also provides an engine, which includes the above-mentioned compression ignition pre-combustion chamber structure, and the plunger drive mechanism includes a plunger camshaft that is transmission-connected to one of the engine crankshaft or the engine camshaft, and the plunger camshaft drives the plunger body to reciprocate through the plunger drive cam.

[0023] The plunger camshaft is driven by the engine crankshaft or the engine camshaft through a gear system or a belt, wherein the transmission ratio between the plunger camshaft and the engine crankshaft is 1:2, and the transmission ratio between the plunger camshaft and the engine camshaft is 1:1. In this way, within one engine cycle, the plunger body completes a complete reciprocating motion, that is, it runs from the upper limit position of the pre-combustion body hole to the lower limit position, and then returns to the upper limit position; and by utilizing the variable valve timing technology on the existing engine camshaft, the timing of the plunger-driven cam can also be variable. In this way, the moment when the high-temperature and high-pressure mixture in the pre-combustion chamber is injected into the main combustion chamber can be controlled, thereby achieving the purpose of controlling combustion.

[0024] The present invention also provides an engine operation method, which uses the above-mentioned engine, the engine is operated in a four-stroke engine operation mode, and outputs power to the outside. The specific operation method is as follows:

[0025] In the early stage of the engine compression stroke, the plunger body is at the upper limit position, the injection channel connects the main combustion chamber and the pre-combustion chamber, the pre-combustion chamber has the largest volume, and the gradually upward piston presses the fresh mixture into the pre-combustion chamber;

[0026] At the end of the compression stroke of the engine, the plunger body begins to move downward, and the injection channel and the pre-combustion chamber are not connected. The gradually descending plunger body compresses the pre-combustion chamber mixture, causing the pre-combustion chamber mixture to spontaneously ignite or partially burn, causing the pre-combustion chamber temperature and pressure to rise. When the plunger body moves downward to the lower limit, the injection hole is connected to the injection channel, and the high-temperature and high-pressure mixture in the pre-combustion chamber is injected into the main combustion chamber through the injection hole and the injection channel in turn, thereby igniting the lean mixture in the main combustion chamber.

[0027] In the early stage of the engine power stroke, the engine exhaust stroke and the engine intake stroke, the plunger body is kept at the lower limit position, the volume of the pre-combustion chamber is kept at a minimum, and the residual exhaust gas in the pre-combustion chamber is minimized;

[0028] At the end of the intake stroke of the engine, the plunger gradually moves upward to the upper limit, the injection channel and the pre-combustion chamber are connected, the volume of the pre-combustion chamber is maximized, and as much fresh mixed gas as possible enters the pre-combustion chamber through the injection channel;

[0029] After that, the engine re-enters the compression stroke and the engine completes a full cycle.

[0030] The engine provided by the present invention has the following beneficial effects: the combustible mixture in the pre-combustion chamber is compressed and ignited, the ignition in the pre-combustion chamber is more stable, the cycle variation of the engine is reduced, the engine can use a thinner mixture, the thermal efficiency of the engine is improved and pollutant emissions are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below in conjunction with the accompanying drawings and embodiments;

[0032] Figure 1 is a cross-sectional view of an embodiment of the engine provided by the present invention, wherein two arrows indicate upward and downward directions respectively;

[0033] Figure 2 The present invention provides a compression ignition pre-combustion chamber structure, and a cross-sectional view of a plunger body of one embodiment thereof when the plunger body is at the upper limit position, wherein two arrows indicate the upward direction and the downward direction respectively;

[0034] Figure 3 The present invention provides a compression ignition type pre-combustion chamber structure, and a cross-sectional view of a plunger body of one embodiment thereof when the plunger body is at the lower limit position, wherein two arrows indicate the upward direction and the downward direction respectively;

[0035] Figure 4 The present invention provides an engine, and a schematic diagram of the positions of a piston and a plunger body during a cycle of an embodiment thereof. DETAILED DESCRIPTION

[0036] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0037] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0038] In the description of the present invention, if there are words such as "several", it means one or more, "more" means more than two, greater than, less than, exceed, etc. are understood as not including the number, and above, below, within, etc. are understood as including the number.

[0039] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0040] Reference Figures 1 to 3 The engine of the present invention is implemented as follows:

[0041] The engine is a reciprocating piston internal combustion engine. The engine of this embodiment includes a compression ignition pre-combustion chamber structure, which includes: a pre-combustion body 900 and an engine cylinder, wherein the engine cylinder includes a cylinder body 700, a cylinder head 800 covered on the top of the cylinder body 700, the cylinder head 800 is provided with an intake duct 810 and an exhaust duct 820, the intake duct 810 is provided with an intake valve 830, and the exhaust duct 820 is provided with an exhaust valve 840, a piston 100 is slidably installed in the cylinder body 700, and the piston 100, the cylinder body 700 and the cylinder head 800 surround a main combustion chamber 200.

[0042] In order to reduce assembly errors, the pre-combustion body 900 in this embodiment is a part of the cylinder head 800. During processing, this embodiment directly processes a part of the pre-combustion body 900 on the cylinder head 800 to reduce the number of engine parts.

[0043] In some other embodiments, a pre-combustion body 900 may also be additionally designed and then installed on the cylinder head 800 .

[0044] The top of the pre-combustion body 900 is provided with a pre-combustion body hole 300 extending axially up and down. The pre-combustion body hole 300 is a blind hole structure. A plunger body 400 is slidably arranged in the pre-combustion body hole 300. The lower end of the plunger body 400 slides and seals against the inner wall of the pre-combustion body hole 300.

[0045] The lower end of the plunger body 400 is recessed with a pre-combustion cavity 410, which is an open cavity structure. The pre-combustion cavity 410, the bottom surface of the pre-combustion body hole 300 and the side wall together define a pre-combustion chamber 600. The wall of the pre-combustion body hole 300 is provided with an injection channel 310. One end of the injection channel 310 is connected to the main combustion chamber 200, and the other end of the injection channel 310 is arranged on the side wall of the pre-combustion body hole 300. The injection channel 310 is a circular pipe-like structure. The injection channel 310 of this embodiment is directly processed on the cylinder head 800, which also reduces assembly errors. The injection channel 310 can adopt a circular straight pipe structure, which is convenient for drilling technology, or a pipe-like structure of other shapes.

[0046] The present embodiment is provided with a plunger driving mechanism 500, which is used to drive the plunger body 400 to reciprocate up and down in the pre-combustion body hole 300. Specifically: the pre-combustion body hole 300 of the present embodiment is a stepped blind hole structure, which is shaped like a "T" shape, and then the pre-combustion body hole 300 of the present embodiment includes an upper large hole 320 and a lower small hole 330 connected up and down, and a step surface is formed between the upper large hole 320 and the lower small hole 330, and the plunger body 400 is a "T"-shaped shaft structure, and the plunger body 400 includes a large head 420 and a small head 430 connected in sequence, wherein the lower end of the small head 430 is slidably mounted on the lower small hole 330, and the large head 420 is located in the upper large hole 320, and the plunger driving mechanism 500 includes a plunger camshaft 53 0. The plunger driving cam 520 and the plunger spring 510. The plunger spring 510 is located between the big head 420 and the step surface in the pre-combustion body hole 300. The plunger spring 510 is sleeved on the outer peripheral side of the upper end of the small head 430, so as to limit the plunger spring 510. The big head 420 is flexibly connected to the step surface through the plunger spring 510. The plunger driving cam 520 is connected to the plunger camshaft 530. The outer cam surface of the plunger driving cam 520 is in conflict with the top of the plunger body 400. The elastic force of the plunger spring 510 prompts the big head 420 of the plunger body 400 to press the cam surface. The rotating plunger driving cam 520 overcomes the elastic force of the plunger spring 510 and prompts the plunger body 400 to reciprocate in the pre-combustion body hole 300, thereby realizing the volume change of the pre-combustion chamber 600.

[0047] An injection hole 411 is provided on the side wall of the pre-combustion cavity 410, and the injection hole 411 corresponds to the other port of the injection channel 310. When the plunger body 400 moves to the upper limit position, the injection channel 310 directly connects the main combustion chamber 200 and the pre-combustion chamber 600. When the plunger body 400 moves to the lower limit position, the pre-combustion chamber 600 is connected to the injection channel 310 through the injection hole 411, so that the pre-combustion chamber 600 is connected to the main combustion chamber 200. In the process of the plunger body 400 moving between the lower limit position and the upper limit position, the side wall of the pre-combustion cavity 410 blocks the other port of the injection channel 310.

[0048] The injection hole 411 is a through-hole structure, and its shape can be a circular hole, an ellipse, a rounded rectangle, etc.

[0049] In order to allow the injection hole 411 to accurately correspond to and connect with the injection channel 310, a first circumferential positioning portion 321 is provided on the side wall of the large hole 320 at the upper end of the pre-combustion body hole 300, and a second circumferential positioning portion 421 is provided on the outer circumferential wall of the large head 420. The first circumferential positioning portion 321 and the second circumferential positioning portion 421 are slidably matched. In this embodiment, the first circumferential positioning portion 321 is a keyway, and the second circumferential positioning portion 421 is a convex key. The convex key and the keyway cooperate with each other for circumferential positioning of the plunger body 400.

[0050] In some other embodiments, the circumferential positioning between the plunger body 400 and the pre-combustion body hole 300 may also be performed in other positioning manners, such as pin positioning.

[0051] Furthermore, in order to increase the ignition source, the number of the injection channels 310 and the injection holes 411 are both multiple, and the multiple injection channels 310 are circumferentially arranged on the inner end side wall of the pre-combustion body hole 300, and the multiple injection holes 411 are circumferentially arranged on the side wall of the pre-combustion inner cavity 410. In this embodiment, the inner end side wall of the pre-combustion body hole 300 is circumferentially symmetrically provided with 4-8 injection channels 310. The circumferential position of the injection channel 310 is determined according to the flow conditions of the mixed gas in the cylinder, and can also be arranged asymmetrically.

[0052] In order to prevent the high-temperature and high-pressure mixed gas in the pre-combustion chamber 600 from leaking, the outer peripheral wall of the small head 430 of the plunger body 400 is provided with multiple annular grooves 431, and each annular groove 431 is sleeved with a plunger ring. Specifically, this embodiment is provided with three annular grooves 431, which are the first annular groove, the second annular groove and the third annular groove arranged in sequence from top to bottom, and the injection hole 411 is located between the first annular groove and the second annular groove. In this way, the plunger body 400 is in sliding sealing contact with the side wall of the pre-combustion body hole 300 through multiple plunger rings, thereby improving the sealing between the plunger body 400 and the pre-combustion body hole 300, and preventing the high-temperature and high-pressure mixed gas in the pre-combustion chamber 600 from leaking.

[0053] In addition, a guide structure and a reinforcing rib structure are provided in the pre-combustion cavity 410. The guide structure is used to guide the flow of the mixture in the pre-combustion chamber 600, and the reinforcing rib structure is used to strengthen the structural strength. At the same time, a thermal insulation coating is applied on the surface of the wall surface, the guide structure and the reinforcing rib structure of the pre-combustion cavity 410. The thermal insulation coating can reduce the heat transfer loss between the high-temperature mixture in the pre-combustion chamber 600 and the wall surface.

[0054] In addition, the flow guide or reinforcing rib structure can be adjusted according to the type of fuel and the composition of the mixed gas to achieve the purpose of adjusting the volume of the pre-combustion chamber 600.

[0055] In some other implementations, the reciprocating motion of the plunger body 400 may also be driven by other driving methods, including hydraulic drive, electric drive, worm gear, etc.

[0056] The present embodiment adopts a driving mode in which the plunger driving cam 520 cooperates with the plunger spring 510. The pre-combustion chamber combustion control of the present invention is achieved by controlling the timing of the plunger driving cam 520, and when in use, the plunger camshaft 530 can be connected to the engine crankshaft or one of the engine camshafts through transmission, and the plunger camshaft 530 is driven by the engine crankshaft or the engine camshaft through a gear system or a belt, wherein the transmission ratio between the plunger camshaft 530 and the engine crankshaft is 1:2, and the transmission ratio between the plunger camshaft 530 and the engine camshaft is 1:1. In this way, within one engine cycle, the plunger body 400 completes a complete reciprocating motion, that is, it runs from the upper limit position of the pre-combustion body hole 300 to the lower limit position, and then returns to the upper limit position; and by utilizing the variable valve timing technology on the existing engine camshaft, the timing of the plunger driving cam 520 can also be variable. In this way, the moment when the high-temperature and high-pressure mixture in the pre-combustion chamber 600 is injected into the main combustion chamber 200 can be controlled, thereby achieving the purpose of controlling combustion.

[0057] In this embodiment, the plunger driving mechanism 500 is used to drive the plunger body 400 to reciprocate axially in the pre-combustion body hole 300, thereby changing the volume of the pre-combustion chamber 600, compressing the fresh mixture in the pre-combustion chamber 600, and promoting the self-ignition of the fuel in the fresh mixture or a partial combustion reaction.

[0058] When the plunger body 400 is at the upper limit of the pre-combustion body hole 300, the volume of the pre-combustion chamber 600 is the largest. At this time, the injection channel 310 directly connects the main combustion chamber 200 and the pre-combustion chamber 600, and the main combustion chamber 200 and the fresh mixed gas can enter the pre-combustion chamber 600 through the injection channel 310;

[0059] When the plunger body 400 is at the lower limit of the pre-combustion body hole 300, the volume of the pre-combustion chamber 600 is the smallest, the mixed gas in the pre-combustion chamber 600 is compressed and self-ignites or partially burns, and the injection hole 411 connects the injection channel 310, the pre-combustion chamber 600 and the main combustion chamber 200, and the high-temperature and high-pressure mixed gas after the reaction in the pre-combustion chamber 600 enters the main combustion chamber 200 to ignite the lean fresh mixed gas;

[0060] When the plunger body 400 is at other positions between the upper limit position and the lower limit position, the injection channel 310 is blocked by the side wall of the pre-combustion cavity 410, and the connection between the pre-combustion chamber 600 and the main combustion chamber 200 is disconnected.

[0061] The present technology moves the plunger body 400 to different positions and utilizes the side wall of the pre-combustion cavity 410 to keep the pre-combustion chamber 600 and the main combustion chamber 200 connected and disconnected through the injection channel 310, so that the mixed gas in the main combustion chamber 200 can enter the pre-combustion chamber 600 through the injection channel 310, and the high-temperature mixture after combustion in the pre-combustion chamber 600 can enter the main combustion chamber 200 through the injection hole 411 and the injection channel 310.

[0062] In this way, the combustible mixture in the pre-combustion chamber 600 is compressed and ignited, and there is no need to arrange an ignition device on the pre-combustion chamber 600. In addition, the compression ignition significantly reduces the requirements for the organization of the mixture in the pre-combustion chamber 600, and there is no need to arrange a fuel injection device on the pre-combustion chamber 600, thereby eliminating a set of ignition devices and fuel injection devices, with a simple structure and low cost.

[0063] For fuels with high ignition energy, such as ammonia fuel, it is difficult for existing ignition devices to ignite the mixture in the pre-combustion chamber. However, the compression ignition of the present invention can make the mixture in the pre-combustion chamber 600 reliably self-ignite or undergo a partial combustion reaction, making it possible to use this type of fuel in the engine.

[0064] This embodiment also provides an operating method of the above engine, and the specific operating method is as follows:

[0065] In the early stage of the engine compression stroke, the plunger body 400 is at the upper limit position, the injection channel 310 connects the main combustion chamber 200 and the pre-combustion chamber 600, the pre-combustion chamber 600 has the largest volume, and the gradually upward piston 100 presses as much fresh mixed gas as possible into the pre-combustion chamber 600;

[0066] At the end of the compression stroke of the engine, the plunger body 400 starts to move downward under the push of the plunger driving cam 520. At this time, the injection channel 310 and the pre-combustion chamber 600 are not connected, and the main combustion chamber 200 and the pre-combustion chamber 600 are not connected. The gradually descending plunger body 400 compresses the fresh mixed gas in the pre-combustion chamber 600. Since the fresh mixed gas in the pre-combustion chamber 600 has undergone a compression process in the main combustion chamber 200, its pressure and temperature have risen. After being compressed again with a very small compression ratio in the pre-combustion chamber 600, it can reach a state of autoignition or partial combustion reaction. The reaction of the mixed gas in the pre-combustion chamber 600 causes the temperature and pressure to rise.

[0067] When the plunger body 400 moves downward to the lower limit position, the injection hole 411 is connected with the injection channel 310, and the high-temperature and high-pressure mixed gas in the pre-combustion chamber 600 is injected into the main combustion chamber 200 through the injection hole 411 and the injection channel 310 in sequence, thereby igniting the lean mixed gas in the main combustion chamber 200;

[0068] During the power stroke of the engine, the plunger body 400 is kept at the lower limit position, keeping the volume of the pre-combustion chamber 600 at a minimum, so that the residual exhaust gas in the pre-combustion chamber 600 is minimized;

[0069] During the exhaust stroke of the engine, the plunger body 400 is kept at the lower limit position, so that the volume of the pre-combustion chamber 600 is kept at a minimum, and the residual exhaust gas in the pre-combustion chamber 600 is minimized;

[0070] And in the early stage of the engine intake stroke, the plunger body 400 is kept at the lower limit position, keeping the volume of the pre-combustion chamber 600 at a minimum, so that the residual exhaust gas in the pre-combustion chamber 600 is minimized;

[0071] At the end of the intake stroke of the engine, the plunger body 400 gradually moves upward to the upper limit position under the action of the plunger spring 510, the injection channel 310 is connected with the pre-combustion chamber 600, and the volume of the pre-combustion chamber 600 is maximized, so that as much fresh mixed gas as possible enters the pre-combustion chamber 600 through the injection channel 310;

[0072] Afterwards, the engine re-enters the compression stroke, the engine completes a full cycle, and the plunger body 400 completes a full reciprocating motion.

[0073] In this way, the combustible mixture in the pre-combustion chamber 600 is compressed and ignited, the ignition in the pre-combustion chamber 600 is more stable, the cycle variation of the engine is reduced, and the engine can use a thinner mixture, thereby improving the thermal efficiency of the engine and reducing pollutant emissions.

[0074] The preferred embodiments of the present invention are specifically described above, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A compression ignition pre-combustion chamber structure, characterized in that: It includes: A pre-combustion body (900) and an engine cylinder, wherein a main combustion chamber (200) formed in the inner space of a piston (100) and the engine cylinder is provided in the engine cylinder, the pre-combustion body (900) is provided with a pre-combustion body hole (300) of a blind hole structure, a plunger body (400) is slidably mounted in the pre-combustion body hole (300), the plunger body (400) is connected to a plunger driving mechanism (500) for driving the plunger body (400) to reciprocate along the axial direction of the pre-combustion body hole (300), the inner end surface of the plunger body (400) is provided with a pre-combustion inner cavity (410) of an open cavity structure, the pre-combustion inner cavity (410), the bottom surface and the side surface of the pre-combustion body hole (300) are The walls define a pre-combustion chamber (600) together, the inner end side wall of the pre-combustion body hole (300) is provided with an injection channel (310) connected to the main combustion chamber (200), the side wall of the pre-combustion inner cavity (410) is provided with an injection hole (411) corresponding to the injection channel (310), and the plunger body (400) has an upper limit position and a lower limit position during the reciprocating movement, the plunger body (400) is in the upper limit position so that the injection channel (310) is directly connected to the main combustion chamber (200) and the pre-combustion chamber (600), and the plunger body (400) is in the lower limit position so that the injection hole (411) connects the injection channel (310), the pre-combustion chamber (600) and the main combustion chamber (200); The side wall of the pre-combustion body hole (300) is provided with a first circumferential positioning portion (321), and the plunger body (400) is provided with a second circumferential positioning portion (421) that is slidably matched with the first circumferential positioning portion (321); The outer peripheral wall of the plunger body (400) is provided with a plurality of annular grooves (431), the annular grooves (431) are sleeved with plunger rings, and the injection hole (411) is arranged between two adjacent annular grooves (431).

2. A compression ignition pre-combustion chamber structure according to claim 1, characterized in that: The inner end side wall of the pre-combustion body hole (300) is provided with a plurality of injection channels (310) arranged circumferentially, and the side wall of the pre-combustion inner cavity (410) is provided with a plurality of injection holes (411) which are arranged in the same circumferential position as the injection channels (310).

3. A compression ignition type pre-combustion chamber structure according to claim 1, characterized in that: The pre-combustion body hole (300) is a "T"-shaped stepped structure, the pre-combustion body hole (300) comprises a large hole (320) at the upper end and a small hole (330) at the lower end, the plunger body (400) is a "T"-shaped shaft-like structure, the plunger body (400) comprises a large head (420) arranged in the large hole (320) at the upper end, and a small head (430) sleeved in the small hole (330) at the lower end, the plunger driving mechanism (500) comprises a plunger spring (510), a plunger driving cam (520), and a plunger cam shaft (530), the large head (420) is flexibly connected to the step surface of the pre-combustion body hole (300) through the plunger spring (510), the plunger driving cam (520) is mounted on the plunger cam shaft (530), and the outer peripheral surface of the plunger driving cam (520) is in contact with the top end of the plunger body (400).

4. A compression ignition type pre-combustion chamber structure according to claim 1, characterized in that: The pre-combustion inner cavity (410) is provided with a flow guide structure for guiding the flow of mixed gas in the pre-combustion chamber (600) and a reinforcing rib structure for enhancing structural strength.

5. A compression ignition pre-combustion chamber structure according to claim 4, characterized in that: The wall surface, flow guide and reinforcing rib structure of the pre-combustion inner cavity (410) are coated with a heat insulation coating.

6. A compression ignition type pre-combustion chamber structure according to claim 1, characterized in that: The engine cylinder comprises a cylinder block (700) and a cylinder head (800), and the pre-combustion body (900) is a part of the cylinder head (800).

7. An engine, characterized in that: It comprises a compression ignition pre-combustion chamber structure as claimed in any one of claims 1 to 6, wherein the plunger drive mechanism (500) comprises a plunger camshaft (530) drivingly connected to one of an engine crankshaft or an engine camshaft, and the plunger camshaft (530) drives the plunger body (400) to reciprocate via a plunger drive cam (520).

8. A method for operating an engine, characterized in that: It includes the engine as claimed in claim 7, which is operated in a four-stroke engine mode and outputs power externally. The specific operation method is as follows: In the early stage of the engine compression stroke, the plunger body (400) is at the upper limit position, the injection channel (310) connects the main combustion chamber (200) and the pre-combustion chamber (600), the pre-combustion chamber (600) has the largest volume, and the gradually upward piston (100) presses the fresh mixed gas into the pre-combustion chamber (600); At the end of the compression stroke of the engine, the plunger body (400) begins to move downward, the injection channel (310) and the pre-combustion chamber (600) are disconnected, and the gradually descending plunger body (400) compresses the mixed gas in the pre-combustion chamber (600), causing the mixed gas in the pre-combustion chamber (600) to spontaneously ignite or partially burn, causing the temperature and pressure of the pre-combustion chamber (600) to rise. When the plunger body (400) moves downward to the lower limit position, the injection hole (411) is connected to the injection channel (310), and the high-temperature and high-pressure mixed gas in the pre-combustion chamber (600) is injected into the main combustion chamber (200) through the injection hole (411) and the injection channel (310) in sequence, thereby igniting the lean mixed gas in the main combustion chamber (200); In the early stages of the engine power stroke, the engine exhaust stroke and the engine intake stroke, the plunger body (400) is kept at the lower limit position, so that the volume of the pre-combustion chamber (600) is kept at a minimum, and the residual exhaust gas in the pre-combustion chamber (600) is minimized; At the end of the engine intake stroke, the plunger body (400) gradually moves upward to the upper limit position, the injection channel (310) and the pre-combustion chamber (600) are connected, and the volume of the pre-combustion chamber (600) is maximized, so that as much fresh mixed gas as possible enters the pre-combustion chamber (600) through the injection channel (310); After that, the engine re-enters the compression stroke and the engine completes a full cycle.

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