Diesel high-pressure injection active pre-combustion chamber and ignition mechanism for rotor engine

Abstract

The invention provides a diesel high-pressure injection active pre-combustion chamber and an ignition mechanism for a rotor engine, and belongs to the technical field of engines, the upper part of the pre-combustion chamber is provided with two mounting channels, namely a fuel injector mounting channel and a spark plug mounting channel, and the lower part of the pre-combustion chamber is provided with three channels capable of communicating an inner cavity with the outside at intervals; the three channels are an air inlet channel, an oil discharge channel and a flame jet flow channel. According to the active pre-combustion chamber structure, through design of the position relation and the area size of the air inlet channel, the oil discharging channel and the flame jet flow channel, stable combustion in the pre-combustion chamber and smooth development of flames are achieved. The invention further provides an ignition mechanism. The ignition mechanism comprises a pre-combustion chamber body, a high-pressure oil sprayer and a spark plug. According to the ignition mechanism, direct injection and ignition control in the rotor engine diesel cylinder is achieved through the high-pressure oil injector.

Description

Technical Field

[0001] The invention belongs to the technical field of engines, and in particular relates to a diesel high-pressure injection active pre-combustion chamber and an ignition mechanism for a rotary engine. Background Art

[0002] The rotary engine is a rotary internal combustion engine that eliminates the crank-connecting rod mechanism of the reciprocating engine and converts the linear motion of the piston in the reciprocating engine into the rotary motion of the rotary piston. The energy generated by the combustion of fuel inside the piston cavity drives the piston to rotate. The rotary piston divides the internal space of the rotary engine into three piston chambers. The piston chamber where the combustion process takes place is called the main combustion chamber. The rotary engine cylinder body is provided with an intake duct and an exhaust duct. During the rotation of the rotor, the three piston chambers are alternately connected and disconnected with the intake duct and the exhaust duct to complete the four strokes of intake, compression, power, and exhaust.

[0003] At present, most rotary engines generally adopt premixed combustion of intake duct injection fuel and direct ignition by spark plugs in the cylinder. Considering the stability of ignition, there is also a passive precombustion chamber ignition scheme in which a precombustion chamber is set on the engine cylinder and the spark plug is installed in the precombustion chamber.

[0004] However, the premixing method of intake port injection cannot achieve precise combustion control and there is also the risk of knocking; at the same time, the rotary engine has a high speed and the allowed injection duration is short, so the use of high-pressure direct injection in the cylinder is more conducive to combustion control. The high-pressure injection in the cylinder can be directly injected into the cylinder, but because the compression ratio of the rotary engine is much smaller than that of the reciprocating engine, the combustion chamber is narrow and long, and the air flow movement in the combustion chamber is a circumferential movement along the rotation of the rotary piston, so the penetration distance of the fuel injection to the combustion chamber is short, and the oil-gas mixing is poor. Therefore, it is more advantageous to use a high-pressure injector to perform jet ignition in the pre-combustion chamber for direct injection in the cylinder. Summary of the invention

[0005] The purpose of the present invention is to solve the above-mentioned problems. The present invention provides an active precombustion chamber solution for injecting diesel into the precombustion chamber, including a new active precombustion chamber structure. The structure ensures a suitable air-fuel ratio in the precombustion chamber through the design of the oil unloading channel, and the flame jet channel and the position relationship of the high-pressure injector and the spark plug are designed so that the flame generated in the precombustion chamber can be stably jetted to the main combustion chamber.

[0006] The present invention provides an active pre-combustion chamber, which comprises a pre-combustion chamber body, which is a sphere and has a pre-combustion chamber inner cavity.

[0007] The active pre-combustion chamber has two major structural features. First, there are two installation channels on the upper part of the pre-combustion chamber, They are respectively an injector installation channel and a spark plug installation channel; secondly, three channels are arranged at intervals in the lower part of the pre-combustion chamber, namely an air intake channel, an oil unloading channel and a flame jet channel.

[0008] A vertical plane is drawn through the center of the spherical body of the pre-combustion chamber, and an XY coordinate system is established with the center of the pre-combustion chamber body as the zero point, and the pre-combustion chamber body is divided into four quadrants, namely quadrant I, quadrant II, quadrant III and quadrant IV.

[0009] The injector mounting channel and the spark plug mounting channel are used to install high-pressure injectors and spark plugs. The injector mounting channel is located directly above the pre-combustion chamber, with the Y-axis as the central axis of the injector mounting channel; the spark plug mounting channel is located in the I quadrant, on one side of the injector mounting channel, and the central axis of the spark plug mounting channel passes through the center of the spherical body of the pre-combustion chamber.

[0010] The oil unloading channel is located directly below the pre-combustion chamber body, with the Y axis as the central axis of the oil unloading channel. The Y axis and the bottom of the pre-combustion chamber body have an intersection, and a circular hole is made with the intersection as the center as the oil unloading channel. The size of the area S1 of the oil unloading channel is related to the conical oil beam sprayed by the high-pressure injector.

[0011] When diesel is sprayed from the nozzle of the high-pressure injector, a cone-shaped oil beam is formed. The spray cone angle θ is related to the nozzle diameter D. n , fuel density in the precombustion chamber ρ a , injection pressure P inj , background pressure P a , dynamic viscosity in the precombustion chamber μ a related. The formula is as follows:

[0012]

[0013] Furthermore, the size of the intersection area S2 of the oil beam at the bottom of the pre-combustion chamber can be obtained, and the intersection area S2 is related to the spray cone angle θ and the diameter h of the spherical body of the pre-combustion chamber. The formula is as follows:

[0014]

[0015] Furthermore, there is a certain proportional relationship between the area S1 of the oil unloading channel and the intersection area S2 of the oil beam at the bottom of the pre-combustion chamber, and the oil unloading proportional coefficient is K. The formula is as follows:

[0016] Where 0 <K<1

[0017] The intake passage is located in the third quadrant, on the intake side of the pre-combustion chamber. At the beginning of the compression stroke of the rotor machine, the airflow brought by the rotor movement should enter the pre-combustion chamber through the intake passage. Therefore, the opening direction of the intake passage is arranged along the tangent direction of the airflow movement as much as possible. The tangent angle between the intake passage and the airflow at the intake passage through hole is α1. The tangent angle α1 between the central axis of the intake passage and the airflow movement should be as small as possible, wherein 0°≤α1≤5°.

[0018] Furthermore, the area S3 of the air intake channel is the difference between the intersection area S2 of the oil beam at the bottom of the pre-combustion chamber and the area S1 of the oil unloading channel. The formula is as follows:

[0019] S3=S2-S1

[0020] The flame jet channel is located in the IV quadrant, on the same side as the spark plug mounting channel. The opening direction of the flame jet channel is arranged along the tangent direction of the airflow movement as much as possible. The tangent angle between the flame jet channel and the airflow at the spark plug jet channel through hole is α2. The tangent angle α2 between the central axis of the flame jet channel and the airflow movement should be as small as possible, where 0°≤α2≤5°.

[0021] Furthermore, the area S4 of the flame jet channel is equal to the area S3 of the air inlet channel. The formula is as follows:

[0022]

[0023] The advantage of the active pre-combustion chamber structure provided by the present invention is that, compared with the prior art, the oil unloading channel can make part of the diesel sprayed by the injector be discharged directly, and part of it remain in the pre-combustion chamber cavity. The size of the oil unloading channel area can be determined according to the demand for the oil unloading amount. For example, if half of the diesel needs to be unloaded, the intersection surface of the oil unloading channel and the oil beam at the bottom of the pre-combustion chamber should satisfy the area ratio relationship of 1:2, that is, the oil unloading ratio coefficient At the same time, the air intake channel is arranged along the tangent direction of the air flow as much as possible to ensure sufficient oxygen in the pre-combustion chamber. The flame jet channel is not only arranged along the tangent direction of the air flow, but also has an area of ​​half the area of ​​the air intake channel. According to Bernoulli's principle, in the process of fluid flow, the greater the flow rate, the smaller the pressure; the smaller the flow rate, the greater the pressure. The flame jet channel area is small, the air flow rate is fast and the pressure is small, and the pressure difference between the flame jet channel and the pre-combustion chamber helps the air flow to bring the flame out. Therefore, the active pre-combustion chamber structure of the present invention can not only ensure the reasonable distribution of the oil and gas volume in the pre-combustion chamber in the cavity, but also smoothly jet the flame into the main combustion chamber.

[0024] The present invention also provides an ignition mechanism, comprising the active pre-combustion chamber, a high-pressure fuel injector and a spark plug.

[0025] Furthermore, during installation, the spray hole of the high-pressure fuel injector head should be flush with the critical surface of the fuel injector installation channel and the inner cavity of the pre-combustion chamber, that is, the fuel injector does not extend into the inner cavity of the pre-combustion chamber.

[0026] Furthermore, during installation, the ignition electrode of the spark plug head should extend into the inner cavity of the pre-combustion chamber, and at the same time, it should be ensured that the ignition electrode is in the first quadrant area.

[0027] The advantage of the ignition mechanism provided by the present invention is that, compared with the prior art, the above-mentioned pre-combustion chamber structure is used and has the advantages of the above-mentioned pre-combustion chamber structure. The spark plug is located in the first quadrant, and part of the diesel sprayed by the high-pressure fuel injector is discharged through the oil discharge channel, and part of it remains in the pre-combustion chamber. The diesel remaining in the pre-combustion chamber evaporates to the upper part of the pre-combustion chamber body, so there is suitable gaseous diesel near the spark plug ignition electrode in the first quadrant. At the same time, the spark plug is arranged on the same side of the flame jet channel, and the ignition electrode is close to the flame jet channel, which is convenient for the airflow to bring the flame into the main combustion chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the internal structure of a traditional rotary engine.

[0029] Figure 2 This is a schematic diagram of the position of the active pre-combustion chamber of the present invention on the rotary engine.

[0030] Figure 3 It is a schematic diagram of the main body of the active pre-combustion chamber of the present invention.

[0031] Figure 4 It is a schematic diagram of the structure of the ignition system of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described with reference to the accompanying drawings and specific embodiments.

[0033] The active pre-combustion chamber structure of the present invention is attached Figure 3 The structure of the active pre-combustion chamber is shown. The active pre-combustion chamber includes a pre-combustion chamber body 1, which is a sphere and has a pre-combustion chamber inner cavity. A vertical plane is drawn through the center of the pre-combustion chamber body 1, and an XY coordinate system is created with the center of the pre-combustion chamber body 1 as the origin, and the pre-combustion chamber body 1 is divided into four quadrants, namely, quadrant I, quadrant II, quadrant III and quadrant IV.

[0034] The active pre-combustion chamber of the present invention is provided with two installation channels on the upper part, namely, the injector installation channel 2 and the spark plug installation channel 3. Figure 3The injector mounting channel 2 is located directly above the pre-combustion chamber, with the Y-axis as the central axis of the injector mounting channel 2; the spark plug mounting channel 3 is located in the first quadrant, on one side of the injector mounting channel 2, and the central axis of the spark plug mounting channel 3 passes through the center of the pre-combustion chamber body 1.

[0035] Please refer to the attached Figure 3 The oil unloading channel 5 is located directly below the pre-combustion chamber body 1, with the Y axis as the central axis of the oil unloading channel 5. The Y axis and the bottom of the pre-combustion chamber body 1 have an intersection, and a circular hole is made with the intersection as the center as the oil unloading channel 5. The size of the area S1 of the oil unloading channel 5 is related to the conical oil beam sprayed by the high-pressure injector 7.

[0036] The diesel fuel is sprayed from the nozzle of the high-pressure injector 7 to form a cone-shaped oil beam. The spray cone angle θ is proportional to the nozzle diameter D. n , fuel density in the precombustion chamber ρ a , injection pressure P inj , background pressure P a , dynamic viscosity in the precombustion chamber μ a The formula is as follows:

[0037]

[0038] Specifically, due to the nozzle diameter D n , injection pressure P inj Parameters such as φ and φ are different under different engine stationary working conditions. The implementation case of the present invention selects a single-hole high-pressure injector 7 with a spray hole diameter of 0.12 mm, and takes a spray cone angle θ of 20° in a specific case.

[0039] The intersection area S2 of the oil beam at the bottom of the pre-combustion chamber is related to the spray cone angle θ and the diameter D1 of the pre-combustion chamber body 1, and the formula is as follows:

[0040]

[0041] Specifically, the diameter h of the pre-combustion chamber body 1 in the embodiment of the present invention is 18 mm, and according to calculation, the intersection area S2 of the oil beam at the bottom of the pre-combustion chamber is 31.64 mm 2. .

[0042] There is a certain proportional relationship between the area S1 of the oil unloading channel 5 and the intersection area S2 of the oil beam at the bottom of the pre-combustion chamber, and the oil unloading proportional coefficient is K. The formula is as follows:

[0043] Where 0 <K<1

[0044] Specifically, the expected oil unloading amount in the implementation case of the present invention is half of the oil injection amount, so the oil unloading ratio coefficient K is taken as According to the calculation, the area S1 of the oil unloading channel 5 is 15.82mm2 .

[0045] The intake channel 4 is located in the third quadrant, on the intake side of the pre-combustion chamber. The tangent angle between the intake channel 4 and the airflow at the through hole of the intake channel 4 is α1. In the implementation example of the present invention, the tangent angle between the intake channel 4 and the airflow at the through hole of the intake channel 4 is α1, which is 5°.

[0046] The area S3 of the intake channel 4 is the difference between the intersection area S2 of the oil beam at the bottom of the pre-combustion chamber and the area S1 of the oil unloading channel 5. The formula is as follows:

[0047] S3=S2-S1

[0048] Specifically, the area S3 of the air intake passage 4 is 15.82 mm 2 .

[0049] The flame jet channel 6 is located in the IV quadrant, on the same side as the spark plug mounting channel 3. The tangent angle between the flame jet channel 6 and the airflow at the through hole of the flame jet channel 6 is α2. In the implementation example of the present invention, the tangent angle between the flame jet channel 6 and the airflow at the through hole of the flame jet channel 6 is 5°.

[0050] The area S4 of the flame jet channel 6 is equal to the area S3 of the air inlet channel 4. The formula is as follows:

[0051]

[0052] Specifically, the area S4 of the flame jet channel 6 is 7.91 mm 2 .

[0053] The present invention provides an active pre-combustion chamber, in which the oil unloading channel 5 can determine the area according to the demand for oil unloading, thereby avoiding the situation where the diesel in the pre-combustion chamber is too concentrated; the air intake channel 4 is arranged along the tangent direction of the airflow as much as possible to ensure sufficient oxygen in the pre-combustion chamber; the flame jet channel 6 is not only arranged along the tangent direction of the airflow, but also has a pressure difference with the pre-combustion chamber due to its small area, thereby ensuring the jet of the flame. Therefore, the design of the three channels enables the active pre-combustion chamber structure of the present invention to ensure the reasonable distribution of the oil and gas volume in the pre-combustion chamber, and to smoothly jet the flame into the main combustion chamber.

[0054] The present invention also provides an ignition mechanism, including an active pre-combustion chamber, a high-pressure fuel injector 7 and a spark plug 8. Figure 4 The injector installation channel 2 is used to install the high-pressure injector 7, and the spark plug installation channel 3 is used to install the spark plug 8.

[0055] When the high-pressure fuel injector 7 is installed, the spray hole at the head of the high-pressure fuel injector 7 is flush with the critical surface between the fuel injector installation channel 2 and the inner cavity of the pre-combustion chamber.

[0056] When the spark plug 8 is installed, the ignition electrode at the head of the spark plug 8 extends into the pre-combustion chamber and is located in the first quadrant.

[0057] An ignition mechanism provided by the present invention has the advantages of the above-mentioned precombustion chamber structure. At the same time, the spark plug 8 is located in the first quadrant. A part of the diesel sprayed by the high-pressure injector 7 is discharged through the oil discharge channel 5, and a part remains in the precombustion chamber. The part of the diesel remaining in the precombustion chamber evaporates to the upper part of the precombustion chamber body 1. Therefore, there is suitable gaseous diesel near the ignition electrode of the spark plug 8 in the first quadrant. The spark plug 8 is arranged on the same side of the flame jet channel, and the ignition electrode is close to the flame jet channel 6, which is convenient for the airflow to bring the flame into the main combustion chamber.

[0058] The following is combined with Figure 3 , 4 To further illustrate the whole process of oil and gas mixing and burning in the pre-combustion chamber, during the compression stroke, the air flow brought by the rotation of the rotor enters the pre-combustion chamber along the intake passage 4, the high-pressure fuel injector 7 in the pre-combustion chamber opens to spray diesel, part of the diesel is directly discharged to the outside of the pre-combustion chamber through the oil discharge hole 5, and part of it remains in the pre-combustion chamber to evaporate and vaporize, the spark plug 8 ignites the diesel, and the flame develops from the flame jet hole 6 into the main combustion chamber along with the air flow.

Claims

1. An active pre-combustion chamber, comprising a pre-combustion chamber body (1), Features: The pre-combustion chamber body (1) is a sphere, and has a pre-combustion chamber inner cavity inside the pre-combustion chamber body (1); the upper part of the pre-combustion chamber body (1) is provided with an injector installation channel (2) and a spark plug installation channel (3), and the lower part of the pre-combustion chamber body (1) is provided with three channels at intervals, namely, an air intake channel (4), an oil discharge channel (5), and a flame jet channel (6); Taking the center of the pre-combustion chamber body (1) as the zero point, an XY coordinate system is created to divide the pre-combustion chamber body (1) into four quadrants, namely quadrant I, quadrant II, quadrant III and quadrant IV; The fuel injector mounting channel (2) and the spark plug mounting channel (3) are used to mount a high-pressure fuel injector (7) and a spark plug (8); the fuel injector mounting channel (2) is located directly above the pre-combustion chamber body (1), with the Y axis as the central axis of the fuel injector mounting channel (2); the spark plug mounting channel (3) is located in the first quadrant, on one side of the fuel injector mounting channel (2), and the central axis of the spark plug mounting channel (3) passes through the center of the pre-combustion chamber body (1); The oil unloading channel (5) is located directly below the pre-combustion chamber body (1), with the Y axis as the central axis of the oil unloading channel (5), the Y axis and the bottom of the pre-combustion chamber body (1) have an intersection, and a circular hole is made with the intersection as the center to serve as the oil unloading channel (5); The air intake channel (4) is located in the third quadrant, the flame jet channel (6) is located in the fourth quadrant, and the air intake channel (4) and the flame jet channel (6) are arranged on both sides of the oil unloading channel (5) along the tangent direction of the airflow movement.

2. The active pre-combustion chamber according to claim 1, Features: The angle α between the tangent line of the airflow at the through hole of the air inlet channel (4) and the air inlet channel (4) 1 , the angle α between the tangent line of the airflow at the through hole of the flame jet channel (6) and the flame jet channel (6) 2 . Where 0°≤α 1 ≤5°、0°≤α 2 ≤5°.

3. The active pre-combustion chamber according to claim 1, Features: The size of the area of ​​the oil unloading channel (5) is related to the conical oil beam sprayed by the high-pressure fuel injector (7). The conical oil beam is calculated by the nozzle hole diameter D according to formula (1): n , fuel density in the precombustion chamber ρ a , injection pressure P inj , background pressure P a , dynamic viscosity in the precombustion chamber μ a The spray cone angle θ of the oil beam is obtained, and then the spray cone angle θ of the oil beam and the diameter D of the pre-combustion chamber body (1) are calculated by formula 2: 1 The intersection area S of the oil beam at the bottom of the pre-combustion chamber is obtained 2 , the intersection area S of the oil beam at the bottom of the pre-combustion chamber is calculated by formula 3 2 The oil unloading ratio coefficient is K, and the area S of the oil unloading channel (5) is calculated. 1 ; where 0 < K < 1 (Equation 3).

4. The active pre-combustion chamber according to claim 1, Features: The intersection area S of the intake channel (4) and the flame jet channel (6) at the bottom of the pre-combustion chamber body (1) is formed by the conical oil beam sprayed by the injector through the formula 4. 2 The area S of the oil unloading channel (5) 1 Determine the area S of the air inlet passage (4) 3 , the area S of the intake passage (4) is calculated by equation 5 3 Determine the area S of the flame jet channel (6) 4 ; S 3 =S 2 -S 1 (Formula 4) 5. An ignition mechanism, comprising the active pre-combustion chamber according to any one of claims 1 to 4, and further comprising a high-pressure fuel injector (7) and a spark plug (8).

6. An ignition mechanism as claimed in claim 5, wherein the spray hole of the head of the high-pressure fuel injector (7) should be flush with the critical surface between the fuel injector installation channel (2) and the inner cavity of the pre-combustion chamber during installation.

7. An ignition mechanism as claimed in claim 6, wherein the ignition electrode at the head of the spark plug (8) should extend into the pre-combustion chamber during installation, and the ignition electrode extending into the pre-combustion chamber is located in the first quadrant.

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