Engine exhaust emission circulation system and method of use

Abstract

The present application relates to a kind of engine exhaust emission circulating system and its use method, belong to energy-saving and emission-reducing technical field, can improve the energy utilization rate when diesel generator burns, reduce exhaust pollution and problem.The engine exhaust emission circulating system of the present application includes engine, oil tank, supplemental combustion combustor, turbine, first compressor, air valve and intercooler, the exhaust gas of engine is burned in supplemental combustion combustor after secondary combustion, and turbine is driven to work, turbine drives compressor rotation to provide the required fresh air for engine and supplemental combustion combustor, while turbine drives generator to generate electricity and recovers residual energy.HC, CO and particulate matter in engine exhaust emission are converted into harmless substances by secondary combustion in the supplemental combustion combustor of the present application through supplemental combustion technology, while providing conditions for inhibiting the generation of NO X , can solve the problem of engine emission, and the secondary combustion of HC, CO, particulate matter and other substances further improves the energy utilization efficiency.

Description

Technical Field

[0001] This invention belongs to the field of energy conservation and emission reduction technology, and relates to an engine exhaust gas recirculation system and its usage method. Background Technology

[0002] In recent years, diesel engines have been used more and more widely, playing an increasingly important role in automobiles, diesel generator sets, general aviation aircraft, and small and medium-sized unmanned aerial vehicles. However, problems such as diesel engine exhaust pollution, high exhaust temperature, and low waste heat utilization efficiency have also become increasingly prominent.

[0003] Diesel engine exhaust pollutants mainly include carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). X Sulfides and particulate matter (PM) are among the substances that pollute the atmospheric environment.

[0004] In existing technologies, measures to suppress the generation of CO and HC during combustion in diesel engines mainly include: increasing the excess air coefficient during combustion, increasing the combustion reaction time, and increasing the cylinder intake temperature; measures to suppress the generation of NO during combustion in diesel engines include: increasing the excess air coefficient during combustion, increasing the combustion reaction time, and increasing the cylinder intake temperature. X The main measures include: reducing the excess air coefficient in the combustion process, reducing the combustion reaction temperature, and shortening the reaction time; as for PM control, diesel engines usually reduce PM generation by increasing the excess air coefficient in the cylinder combustion process and increasing the reaction time.

[0005] Therefore, addressing emissions issues by focusing on the diesel engine itself presents a contradiction and is difficult to achieve. Current solutions involve adding complex exhaust aftertreatment systems, which are heavy and economically inefficient.

[0006] In terms of engine exhaust energy recovery, the most common method currently is exhaust gas turbocharging technology. This technology utilizes the kinetic and internal energy of the exhaust gas to drive the turbine and compressor, further increasing the engine's intake pressure, temperature, and flow rate, ultimately improving the engine's output power. While this method can recover some of the energy contained in the high-temperature exhaust gas from the cylinders, some energy is still wasted. Summary of the Invention

[0007] In view of the above problems, the present invention provides a diesel engine exhaust gas recirculation system and its usage method, which can improve the energy utilization rate of diesel generator combustion and reduce exhaust pollution and problems.

[0008] On one hand, the present invention provides an engine exhaust gas recirculation system, including an engine, a fuel tank, a combustion booster, a turbine, a first compressor, valves, and an intercooler;

[0009] An engine includes intake valves, exhaust valves, and fuel injectors;

[0010] The first compressor is connected to the air valve and the intercooler respectively; the air valve is connected to the air inlet of the afterburning turbocharger; the intake valve is connected to the intercooler, and the fuel injector is connected to the fuel tank; the exhaust valve is connected to the exhaust port of the afterburning turbocharger; the outlet pipe of the afterburning turbocharger is connected to the turbine; and the fuel tank is connected to the fuel inlet of the afterburning turbocharger.

[0011] Optionally, it also includes a fuel injector, and the fuel tank is connected to the fuel inlet of the afterburner booster via the fuel injector.

[0012] Optionally, it also includes a second compressor, with the first compressor connected to the second compressor. The high-pressure gas compressed by the first compressor and the second compressor enters the gas valve and intercooler through the second compressor.

[0013] Optionally, it also includes a generator connected to a first compressor or a second compressor or a turbine.

[0014] Optionally, it also includes an electric motor connected to the first compressor and a generator connected to the turbine.

[0015] Optionally, the afterburning booster includes an engine exhaust pipe, an afterburner, a turbocharger, and an integrated starter-generator motor.

[0016] On the other hand, the method of using an engine exhaust gas recirculation system disclosed in this invention, based on the aforementioned engine exhaust gas recirculation system, specifically includes the following steps:

[0017] The first compressor generates high-pressure gas. Part of the high-pressure gas flows into the afterburning and supercharging device through the gas valve, and the other part of the high-pressure gas flows into the engine cylinder through the intercooler, forming a low-temperature high-pressure gas flow path in the circulation system.

[0018] Fuel in the tank enters the engine's fuel pump, is pressurized, and then injected into the cylinder of the diesel engine through the fuel injector. It mixes and burns with the low-temperature, high-pressure gas from the intercooler, expands and does work to produce exhaust gas, which is discharged from the engine's exhaust valve and enters the secondary combustion zone of the afterburner.

[0019] After being pressurized, the fuel in the fuel tank enters the afterburning booster and is fully mixed with the high-pressure gas from the gas valve before entering the secondary combustion zone of the afterburning booster.

[0020] The high-temperature gas generated in the secondary combustion zone of the burner flows into the turbine, expands, and performs work to generate energy.

[0021] Optionally, the air from the first compressor enters the second compressor for further compression, and the high-pressure gas after two stages of compression enters the afterburning turbocharger and the engine cylinders through the air valve and intercooler, respectively.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] (1) The circulation system of the present invention effectively reduces pollutants in engine exhaust and improves the energy utilization efficiency of the combined cycle system by performing secondary combustion of the exhaust gas from the cylinder and using the exhaust gas energy to generate electricity.

[0024] (2) The exhaust components of the circulation system of the present invention are clean. Compared with ordinary diesel engines, the content of incomplete combustion products such as CO, HC and PM in the engine exhaust is significantly reduced.

[0025] (3) The circulation system of the present invention can achieve output of multiple power modes. Compared with the traditional diesel engine, the circulation system can not only increase the engine intake air volume and engine power through the turbine-compressor, but also recover excess energy in the exhaust gas through the generator at the turbine end. The electrical energy generated by the generator can charge the accessory systems of automobiles, general aviation aircraft, drones, etc., or can be directly stored in the battery.

[0026] (4) The circulating system of the present invention has high energy utilization and high overall cycle thermal efficiency. The typical thermal efficiency of a naturally aspirated diesel engine is 35%, the typical thermal efficiency of a diesel engine with an exhaust gas turbocharger system is 39-42%, and the thermal efficiency of the combined cycle system can reach up to 45%.

[0027] (5) The circulating system of the present invention has a low structural weight, low development cost, and low processing cost. Compared with existing exhaust gas treatment systems, it better meets the current requirements of various fields of power machinery for lightweight design of power systems, and can be further promoted in the fields of automobiles, diesel generator sets, general aviation aircraft, and small and medium-sized drones.

[0028] (6) In the afterburner of this invention, the afterburner is integrated with the engine exhaust pipe. The afterburner converts harmful substances such as HC, CO, and particulate matter in the engine exhaust gas into harmless substances through secondary combustion before the turbocharger turbine. These substances are then discharged into the atmosphere after the turbocharger turbine performs work. Simultaneously, the turbocharger is connected to the starter-generator integrated motor shaft via a coupling. The turbocharger is adjusted and controlled by controlling the power generation of the starter-generator integrated motor. Compared to the traditional turbocharger turbine pre-turbo bleed adjustment method, this invention eliminates the traditional turbine pre-turbo bleed adjustment mechanism, resulting in a simpler turbocharger structure. Excess high-temperature gas energy before the turbine is absorbed by the starter-generator integrated motor, improving the utilization efficiency of engine exhaust energy. Attached Figure Description

[0029] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0030] Figure 1This is a schematic diagram of the turbine-driven generator and single-stage compressor of the engine exhaust gas recirculation system of the present invention.

[0031] Figure 2 This is a schematic diagram of the turbine-driven generator and two-stage compressor of the engine exhaust gas recirculation system of the present invention.

[0032] Figure 3 This is a schematic diagram of the turbine-driven generator and electric motor driving a two-stage compressor in the engine exhaust gas recirculation system of the present invention.

[0033] Figure 4 This is a schematic diagram of the overall structure of the burner of the present invention.

[0034] Figure 5 This is a schematic diagram of the burner jet combustion chamber and some accessories of the present invention.

[0035] Figure 6 This is a schematic diagram of the fuel nozzle structure of the present invention.

[0036] Figure 7 This is a schematic diagram of the fuel nozzle core of the present invention.

[0037] Figure 8 This is a cross-sectional view of the fuel nozzle of the present invention.

[0038] Figure 9 This is a top partial cross-sectional view of the gas cyclone generator of the present invention.

[0039] Figure 10 This is a cross-sectional view of the cantilever rotor in the afterburning booster device of the present invention.

[0040] Figure 11 This invention relates to a combustion booster device.

[0041] Figure label:

[0042] 1. Engine exhaust pipe, 2. Afterburner, 3. Turbocharger, 4. Starter-generator integrated motor, 5. Heat insulation sealing device, 6. Swirl combustion chamber, 7. Jet combustion chamber, 8. Engine exhaust pipe inlet, 9. Afterburner outlet, 10. Turbocharger outlet, 11. Motor bracket, 12. Coupling, 13. Fuel inlet, 14. Air inlet, 15. Heating element, 16. Fuel nozzle core, 17. Gas swirler, 18. Atomizing cylindrical cavity, 19. Secondary swirling zone, 20. Jet zone, 21. Outlet pipe, 22. First exhaust port, 23. Second exhaust port, 24. Swirl orifice, 25. Gas inlet orifice 26. Oil outlet, 27. Spiral oil passage, 28. Gas inlet, 29. Inclined groove, 30. Fuel guide pipe, 31. Oil filling space, 32. Mounting mating hole, 33. Shaft, 34. Radial turbine, 35. Bearing, 36. Centrifugal compressor impeller, 37. Axial and radial damper, 38. Engine, 39. Fuel tank, 40. Cylinder, 41. Crankshaft, 42. Intake valve, 43. Exhaust valve, 44. Fuel pump, 45. Fuel nozzle, 46. Fuel injector, 47. Turbine, 48. Generator, 49. First compressor, 50. Second compressor, 51. Valve, 52. Intercooler, 53. Electric motor. Detailed Implementation

[0043] To better understand the above-described objectives, features, and advantages of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other. Furthermore, the present invention can be implemented in other ways different from those described herein; therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0044] A specific embodiment of the present invention is shown below. Figure 1-3 The present invention discloses an engine exhaust gas recirculation system, and particularly relates to a diesel engine exhaust gas recirculation system, including an engine 38, a fuel tank 39, a booster device, a fuel injector 46, a turbine 47, a first compressor 49, a valve 51 and an intercooler 52.

[0045] The engine includes an intake valve 42, an exhaust valve 43, and a fuel injector 45;

[0046] The outlet of the first compressor is connected to the inlet of the air valve and the inlet of the intercooler via pipelines; the outlet of the air valve is connected to the air inlet of the afterburning turbocharger via a pipeline; the intake valve is connected to the outlet of the intercooler via a pipeline, and the inlet of the fuel injector is connected to the outlet of the fuel tank via a pipeline; the exhaust valve is connected to the exhaust port of the afterburning turbocharger via a pipeline; the outlet pipeline of the afterburning turbocharger is connected to the inlet of the turbine; the outlet of the fuel tank is also connected to the inlet of the fuel injector via a pipeline; and the outlet of the fuel injector is connected to the fuel inlet of the afterburning turbocharger.

[0047] Optionally, the engine 38 also includes a cylinder 40, a crankshaft 41, and a fuel pump 44; the outlet of the fuel tank is connected to a fuel injector 45 via the fuel pump 44.

[0048] Optionally, engine 38 is a diesel engine; the valve is a flow control valve.

[0049] Optionally, the high-pressure gas output by the first compressor is high-pressure air.

[0050] Optionally, it also includes a second compressor 50, with the first compressor 49 connected to the second compressor 50, and the high-pressure gas after two-stage compression enters the gas valve and intercooler through the second compressor.

[0051] Optionally, it also includes a generator 48 for providing energy to the first compressor and the second compressor.

[0052] Optionally, the fuel tank includes a first outlet and a second outlet, the first outlet being connected to a fuel pump or a fuel injector; the second outlet being connected to a fuel injector 46.

[0053] Optionally, see Figure 4-11 The afterburning and turbocharging device includes an engine exhaust pipe 1, an afterburning burner 2, a turbocharger 3, and an integrated starter-generator motor 4.

[0054] The engine exhaust pipe 1 is connected to the afterburner 2; the engine exhaust pipe inlet 8 is connected to the engine exhaust port; the turbocharger outlet 10 is connected to the engine air box; and the air inlet 14 of the afterburner 2 is connected to the engine air box.

[0055] The starter motor 4 is fixed to the turbocharger 3 by the motor bracket 11. The shaft of the starter motor 4 and the shaft of the turbocharger 3 transmit torque through the coupling 12. When the engine starts, the starter motor 4 drives the turbocharger 3 to rotate. The compressed air provided by the turbocharger 3 enters the engine air box through the turbocharger outlet 10, providing scavenging pressure for engine starting, which makes it easier for the engine to start at high altitudes.

[0056] After the engine starts, engine exhaust enters the swirl combustion chamber 6 of the afterburner 2 through exhaust pipe inlet 8 and engine exhaust pipe 1. Simultaneously, compressed air supplied by turbocharger 3 enters the jet combustion chamber 7 of the afterburner 2 through the engine air box and air inlet 14. Fuel enters the jet combustion chamber 7 of the afterburner 2 through fuel inlet 13 and, under the action of silicon nitride heating rod 15, contacts the air entering through air inlet 14, completing the ignition process of the afterburner 2. The ignited high-temperature combustion gas is then ignited by the afterburner 2. The jet combustion chamber 7 enters the swirl combustion chamber 6 of the afterburner 2 and mixes with the engine exhaust entering from the engine exhaust pipe 1 for secondary combustion. During the secondary combustion process, HC and CO in the engine exhaust are converted into harmless water and carbon dioxide. The particulate matter, which has a relatively large mass, has a longer residence time in the swirl combustion chamber 6 under the action of gas swirl, and can be fully combusted. It will eventually be converted into harmless substances and discharged through the afterburner outlet 9. The turbocharger 3 and the afterburner 2 are connected by a flange at the afterburner outlet 9 and the flange face is tightened with a nut.

[0057] Optionally, the engine exhaust pipe 1 is provided with two pipes, which are respectively connected to the first exhaust port and the second exhaust flange.

[0058] The high-temperature exhaust gas from the afterburner 2 enters the turbocharger 3, driving its turbine to perform work. The turbocharger 3 gains more energy, and at this time, the starter-generator 4 switches to generator mode. The turbocharger 3 is controlled by adjusting the amount of electricity generated. Conversely, controlling the amount of fuel entering the turbocharger 3 through the fuel inlet 13 of the afterburner 2 controls the temperature of the high-temperature exhaust gas entering the turbocharger 3, ensuring the turbocharger 3 always operates in its high-efficiency range. This combined control of both methods allows for precise control of the turbocharger 3 without releasing excess high-temperature exhaust gas before the turbine, converting the energy of the exhaust gas that would otherwise be released into electrical energy output. The use of these two control methods maximizes the efficiency of exhaust gas energy recovery.

[0059] A specific example of the working process of this invention is as follows: A heavy-duty diesel engine operates at a speed of 1500 rad / min, with a turbocharger pressure ratio of 1.5, a turbocharger speed of 45000 rad / min, and a turbine bypass valve opening of 20%. The original engine emission data are a soot concentration of 2.9 FSN and a CO concentration of 900 × 10⁻⁶. -6 The THC concentration was 93 × 10⁻⁶. -6 The NOx concentration was 1450 × 10⁻⁶. -6 The total number of particulate matter was 1.75 × 10⁻⁶. 8 # / mL, total particulate matter mass is 3.5×10 -4μg / mL, particulate matter geometric mean diameter is 102.5nm, fuel consumption is 180kg / h, and exhaust temperature is 853K.

[0060] At this point, the supplementary combustion burner of the present invention is used, with an air supply rate of 0.0125 kg / s and an injection rate of 0.000625 kg / s. The fuel-air ratio in the combustion chamber is designed to be 0.0613. The combustion temperature in the jet burner reaches a maximum of 1200 K, and the main combustion zone temperature is 1600 K. After using the supplementary combustion burner of the present invention, the soot concentration decreased from 2.9 FSN to 1.7 FSN, a reduction of 41.3%; the CO concentration decreased from 900 × 10⁻⁶. -6 Reduced to 430×10 -6 It decreased by 38.6%; the THC concentration decreased from 93×10 -6 Reduced to 56×10 -6 It decreased by 39.8%; NO X Concentration from 1450×10 -6 Reduced to 980×10 -6 This represents a 32.4% reduction; the total number of particulate matter decreased from 1.75 × 10⁻⁶. 8 # / mL decreased to 0.82×10 8 # / mL, a decrease of 53.1%; total particulate matter mass was 3.5×10 -4 μg / mL decreased to 2.71×10 -4 μg / mL, a decrease of 22.6%; the geometric mean diameter of particulate matter decreased from 102.5 nm to 85.6 nm, a decrease of 16.5%.

[0061] Due to the closure of the turbocharger bypass valve and the energy from secondary combustion in the afterburner, the energy entering the turbocharger increases. At this point, the turbocharger speed increases from 45,000 rad / min to 53,000 rad / min, and the pressure ratio increases from 1.5 to 1.8. Simultaneously, the pressure sensor in the engine intake manifold detects that the intake pressure ratio exceeds the diesel engine's requirements. The turbocharger system control unit switches the integrated starter-generator 4 from its operating mode to generator mode and increases the generator power to 0.8 kW, resulting in a power output of 0.6 kW / h. By increasing the generator power of the integrated starter-generator, the turbocharger speed is reduced from 53,000 rad / min to 45,000 rad / min, and the pressure ratio is reduced to 1.5, returning to the pressure ratio required for diesel engine operation. Compared to the traditional turbocharger and diesel engine matching method that discharges excess exhaust gas through the exhaust bypass valve, the afterburner proposed in this invention, which improves energy recovery efficiency, achieves greater utilization of exhaust gas energy.

[0062] Optionally, the afterburner includes a heating element 15, a nozzle, a jet combustion chamber 7, and a swirl combustion chamber 6;

[0063] The nozzle includes a fuel nozzle core 16 and a gas swirler 17; the gas swirler 3 includes an atomizing cylindrical cavity 18; the atomizing cylindrical cavity constitutes the primary swirling zone of the jet combustion chamber 5; the jet combustion chamber 7 also includes a secondary swirling zone 19 and a jet zone 20; the fuel nozzle core is used to guide fuel into the primary swirling zone; the primary swirling zone is connected to the secondary swirling zone, and the secondary swirling zone is connected to the jet zone; the heating element is disposed in the secondary swirling zone and is used to ignite the gas mixed with atomized fuel in the secondary swirling zone; the jet zone is connected to the swirling combustion chamber.

[0064] Optionally, the heating element is a silicon nitride heating rod; the introduced gas is air; the primary swirling zone, the secondary swirling zone, and the jet zone are all cylindrical cavities.

[0065] Optionally, the swirl combustion chamber includes multiple shell surfaces. An outlet pipe 21 is provided on the first shell surface, extending from the outside of the shell into the swirl combustion chamber to the center of the chamber. The diameter ratio of the jet zone to the secondary swirl zone is 3:5 to 2:5. A first exhaust port 22 and / or a second exhaust port 23 are respectively provided on a third shell surface and / or a fourth shell surface adjacent to both the first and second shell surfaces. The ratio of the cross-sectional area of ​​the air inlet 14 to the cross-sectional area of ​​the first exhaust port to the cross-sectional area of ​​the second exhaust port is 1:1:1. Further, the ratio of engine displacement to the volume of the mixing combustion chamber is 50:1 to 65:1.

[0066] Furthermore, the cross-section of the swirl combustion chamber is a rounded rectangular cavity or a prototype.

[0067] Optionally, the first exhaust port and the second exhaust port are respectively connected to the engine exhaust pipe 1. The exhaust gas generated after the engine combustion enters the swirl combustion chamber tangentially through the first exhaust port and the second exhaust port. In the swirl combustion chamber, a swirl is formed and fully mixed. HC, CO and carbon nuclei in the engine exhaust gas are further burned and converted into CO2 and H2O in the swirl combustion chamber, while releasing chemical energy.

[0068] Optionally, the first exhaust port and the second exhaust flange are positioned opposite each other on both sides of the swirl combustion chamber, with the outlet pipe 21 as the boundary. The engine exhaust gas enters the swirl combustion chamber tangentially from both sides. At this time, the opposing airflows can easily form a swirl in the combustion chamber and fully mix with the high-temperature gas entering the combustion chamber through the jet zone to achieve a better secondary combustion effect.

[0069] Optionally, a gas inlet hole 25 is provided on the side of the gas inlet section 14 near the secondary vortex zone. The gas inlet hole is a centripetal hole that connects the air inlet section and the secondary vortex zone. The axis of the gas inlet hole is set at an angle to the axis of the secondary vortex zone. When the gas flows through, it can generate tangential velocity, which facilitates the generation of vortex. The cross-sectional area of ​​the gas inlet section and the vortex hole 24 are equal.

[0070] Optionally, the fuel nozzle core 16 is a detachable nozzle, and the end face of the fuel nozzle is sealed by a sealing gasket. The heating element 1 is tightly fitted by bolt preload to achieve a conical surface seal.

[0071] Optionally, the jet zone is connected to the swirl combustion chamber; the chamber volumes of the first-stage swirl zone, jet zone, second-stage swirl zone, and swirl combustion chamber increase sequentially.

[0072] In operation, when the burner starts before the engine: the heating rod 1 preheats first; fuel enters the nozzle through the fuel inlet 13, then passes through the fuel guide pipe, is ejected through the fuel outlet 26, flows through the spiral oil passage 27 on the fuel nozzle core, and enters the inclined groove 29 at the end of the spiral oil passage, being injected into the primary swirl zone; gas enters the gas inlet 28 from the air inlet, part of which flows into the primary swirl zone through the swirl holes, and the other part directly enters the secondary swirl zone from the gas inlet holes of the secondary swirl zone; in the primary swirl zone, the fuel is fully mixed with the gas entering through the swirl holes of the primary swirl generator, and after entering the secondary swirl zone, it is ignited by the heating rod extending into the secondary swirl zone and begins to mix and burn, mixing with the gas from the gas inlet holes of the secondary swirl zone and continuing to burn; then it enters the jet zone, and at the same time the flame propagates in the reverse direction to the primary swirl zone, the heating rod is de-energized, and the ignition process is completed.

[0073] When the engine starts before the burner: After the engine starts, the exhaust gas temperature reaches the threshold temperature (usually 300℃), the heating rod 1 preheats, and the fuel enters the nozzle through the fuel inlet and then enters the inclined groove at the end of the spiral oil passage through the fuel guide pipe 30 and enters the first-stage swirl zone. In the first-stage swirl zone, it mixes with the gas from the air inlet and enters the second-stage swirl zone to begin mixed combustion. Then, it enters the swirl combustion chamber through the jet zone for secondary combustion. In the swirl mixing combustion chamber, it is ignited by the high-temperature exhaust gas, and the flame propagates back to the first-stage swirl zone. Then, the heating rod 1 is turned off, completing the ignition process.

[0074] The high-temperature combustion gas in the first-stage swirl zone enters the second-stage swirl zone to continue mixing and burning with the gas. It then enters the jet zone to expand and accelerate before entering the swirl combustion chamber. There, it mixes with the piston engine exhaust gas entering the swirl combustion chamber through the first exhaust port for secondary combustion. During the secondary combustion process, HC, CO, and carbon nuclei particles continue to burn and are converted into CO2 and H2O, releasing energy. The completely burned gas is discharged through the swirl combustion chamber outlet pipe.

[0075] In this invention, the primary swirl zone achieves thorough mixing of gas and fuel through swirl holes opposite to the inclined groove. Simultaneously, because the gas and fuel flow velocity within the primary swirl zone is slower than in the secondary swirl zone, the mixed gas flow can fully combust in the primary swirl zone, forming the main combustion zone after stable combustion. The secondary swirl zone enables ignition during startup and also serves as a secondary combustion zone for the combustion reaction. First, the gas enters the burner tangentially, creating a pre-swirl effect within the air inlet cavity. A portion enters the primary swirl zone tangentially through swirl holes on the side wall of the primary swirl zone cavity, forming a primary swirl; the other portion enters the secondary swirl zone tangentially through gas inlet holes on the side wall of the gas inlet, generating a secondary swirl. The jet zone accelerates the expansion of the high-temperature combustion gas, leading it into the swirl combustion chamber.

[0076] When the primary swirling zone enters the secondary swirling zone, it forms a primary swirling flow. When the gas enters the secondary swirling zone from the air inlet, it passes through the gas inlet hole (shaped like a swirling hole), naturally generating a swirling flow. Since the gas inlet hole is evenly and circularly distributed along the cross-section, it merges with the primary swirling flow in the secondary swirling zone to form a secondary swirling flow, which strengthens the primary swirling flow.

[0077] The jet is realized through the jet zone, which connects the secondary swirl zone and the swirl combustion chamber. The internal space of the secondary swirl zone is smaller than that of the swirl combustion chamber, which creates a pressure difference on both sides of the jet zone. The swirl is accelerated when it passes through the jet zone, and after entering the swirl combustion chamber, it breaks free from the constraint of the jet zone pipe wall to form a jet.

[0078] Optionally, the nozzle is a fuel atomizing nozzle; the fuel nozzle core 16 includes a first fixed end and a fuel conduction column; the gas swirler 17 includes a fuel inlet, an air inlet 14, and an atomizing cylindrical cavity 18; the first fixed end is provided with a fuel inlet 13; the fuel conduction column is provided with a first column section, a swirling groove 31, and a second column section in sequence, the first column section being close to the first fixed end and the second column section being away from the first fixed end; the first column section is provided with an oil outlet 26 inside and a spiral oil passage 27 on its outer periphery, the oil outlet being close to the first fixed end; the spiral oil passage is spirally arranged on the outer periphery of the first column section between the oil outlet and the swirling groove; the spiral oil passage is used to spirally transmit the fuel output from the oil outlet to the swirling groove; the swirling groove is a radial annular groove along the fuel conduction column; the swirling groove is used to rotate the fuel here and then inject it into the inclined groove; the outer periphery of the second column section is provided with an inclined groove, the inclined groove connecting the swirling groove and the atomizing cylinder. The angle between the axis of the inclined groove and the axis of the second column section and / or the axis of the atomizing cylindrical cavity is α; the inclined groove is used to inject fuel into the atomizing cylindrical cavity; the fuel inlet is connected to the fuel outlet; the fuel inlet is connected to the atomizing cylindrical cavity and includes a receiving cavity and a second fixed end; the receiving cavity is used to receive the fuel conduction column, and the second fixed end is used to connect to the first fixed end; the receiving cavity is provided with a first receiving section and a second receiving section in sequence; the first receiving section is close to the first fixed end, the diameter of the first receiving section is larger than that of the first column section, and an oil injection space 31 is formed between the first receiving section and the first column section, and the fuel outlet is located in the area of ​​the first column section located in the oil injection space; after the fuel flows out from the fuel outlet, it flows into the spiral oil passage through the oil injection space; the atomizing cylindrical cavity and the gas inlet 28 are connected through the swirling hole 24; the compressed air in the gas inlet is rotated through the swirling hole and then introduced into the atomizing cylindrical cavity 18.

[0079] Optionally, m oil outlet holes 26 are provided, where m>=1, and the m oil outlet holes are arranged radially along the first column segment.

[0080] Optionally, the axial length a of the first column segment is 6.5-7.5 mm, preferably 7.25 mm; the axial length c of the swirl channel is 4.5-5.5 mm, preferably 5.25 mm; the axial length e of the second column segment is 0.5-1 mm, preferably 1 mm; the diameters of the first and second column segments are equal, d0 is 3-6 mm, and the diameter d0 can be selected according to the required number of swirl channels. When the number of swirl channels is less than 4, the diameter d0 is 3-4 mm, preferably 3.5 mm; when the number of swirl channels is more than 4, the diameter d0 is 4-6 mm. The radial depth d1 of the swirl channel is 0.15-0.45 mm, preferably 0.3 mm; the cross-sectional area s1 of the swirl channel is 0.01 mm². 2 -0.03mm 2 The preferred size is 0.015mm. 2The radial depth d2 is 0.05-0.15 mm, preferably 0.1 mm; the cross-sectional area s2 of the spiral oil passage is 2ns1-3ns1, preferably 2.5ns1, and more preferably 0.098 mm. 2 Where n is the number of inclined grooves, the radial depth d3 of the spiral oil passage is 0.125-0.375mm, preferably 0.25mm; the total cross-sectional area s3 of the multiple oil outlet holes is 4ms²-5ms², preferably 0.40mm. 2 The diameter d4 is 0.25-0.75mm, preferably 0.5mm; the axial length h of the atomizing cylindrical cavity is 12-14mm, preferably 12mm; the diameter d5 is 2d0-5d0, preferably 13mm; the axial distance b between the swirling orifice and the end face of the second column segment away from the first fixed end is b = L / d5 = 1 / 2, preferably 6.5mm; the cross-sectional area s4 of the swirling orifice is 8mm². 2 -12mm 2 Preferably 10mm 2 The distance L between the midpoint of the swirl hole axis and the corresponding radial plane of the atomizing cylindrical cavity is 5-7 mm, preferably 5.25 mm; the angle α between the axis of the inclined groove and the axis of the second column section and / or the axis of the atomizing cylindrical cavity satisfies α=arctanα=L / (b-1 / 2d0), preferably 30 degrees.

[0081] Optionally, a:b:c:e = 7.25:6.5:5.25:1; d1:d2:d3:d4:d5 = 0.3:0.1:0.25:0.5:13. The number and cross-sectional area of ​​the inclined grooves are related to the total fuel volume; the fuel flow rate used in this embodiment is approximately 20 mg / s, correspondingly, two inclined grooves are used; the orientation of the inclined groove outlet is opposite to the orientation of the swirl hole outlet, which allows the fuel and air to be fully mixed, improving combustion quality; the fuel inlet is connected to the atomizing cylindrical cavity; the first fixed end and the second fixed end are threadedly connected; the first fixed end is a columnar structure, and the second fixed end is a columnar receiving cavity; a sealing gasket 33 is provided at the transition contact surface between the first fixed end and the fuel conduction column, through the first fixed end and... The threaded fastening of the second fixed end presses the sealing gasket against the axial contact surface between the first and second fixed ends to achieve fuel sealing and prevent leakage; the fuel inlet is a multi-segment stepped columnar cavity, with the end segment of the stepped columnar cavity near the first column segment connected to the oil outlet; the end segment of the stepped columnar cavity is a fuel guide pipe with a diameter greater than or equal to the diameter of the oil outlet; the oil outlet is perpendicular to the axis of the end segment of the stepped columnar cavity; multiple swirling holes are provided, and the multiple swirling holes are evenly arranged along the circumference of the atomizing cylindrical cavity; the gas inlet 28 is an annular chamber, and the gas inlet is located in the atomizing cylinder. The outer ring of the cavity; the wall thickness between the gas inlet and the atomizing cylindrical cavity is 0.5-1 times the cross-sectional area s4 of the swirling orifice; it also includes a housing, which is disposed outside the gas inlet for further sealing the gas inlet; an air inlet communicates with the gas inlet for inputting compressed air; the air inlet direction of the air inlet is arranged parallel to the tangential direction of the gas inlet for inputting compressed air into the gas inlet along the tangential direction of the gas inlet; the side of the atomizing cylindrical cavity away from the second fixed end is open for releasing atomized fuel; gas inlet It is a sealed chamber; the gas cyclone separator also includes a mounting hole 32, which is set on the inner wall of the fuel inlet of the gas cyclone separator. The fitting clearance between the fuel nozzle core and the mounting hole is less than or equal to twice the boundary layer thickness when the fuel flows. Together with the swirl groove and the inclined groove, it forms a fuel channel. The small clearance fit prevents fuel leakage when passing through; the fuel conduction column is on the same line as the axis of the atomizing cylindrical cavity; the swirl hole 24 is a centripetal hole; the interface between the swirl hole and the gas inlet is set at an angle to the axis of the swirl hole; the swirl hole is a spiral centripetal hole or a radial planar centripetal hole.

[0082] In use, the fuel nozzle core 16 and the gas cyclone separator 17 are fastened together by threads, and the sealing gasket 33 is pressed to achieve fuel sealing and prevent leakage. The gas cyclone separator is integrated with the outer shell to achieve airtightness between the outer shell and the gas cyclone separator. The air inlet pipe of the air inlet is connected to the outer shell. In use, the fuel inlet on the fuel nozzle core is connected to the external fuel connector by threads, and the air inlet pipe at the air inlet is connected to the external air source, thus realizing the complete fuel nozzle structure function. Fuel enters the fuel injection space through the fuel inlet and the outlet hole, and enters the cyclone groove through the spiral oil channel on the fuel nozzle core to rotate. At this time, after the fuel gains rotation speed, it enters the inclined groove for flow distribution through the spiral oil channel. After entering the inclined groove, it is injected into the atomizing cylindrical cavity in a cone shape. At the same time, compressed air enters the gas inlet tangentially through the air inlet and rotates. Then, it enters the atomizing cylindrical cavity tangentially through the cyclone hole. Since the angle α of the inclined groove 11 in the structure satisfies α=arctanα=L / (b-1 / 2d0), preferably 30 degrees, the high-speed fuel injected by the inclined groove and the high-speed air entering through the swirling hole 24 directly impact and mix in the atomizing cylindrical cavity, and the fuel and air are more uniformly mixed through the direct collision of the gas and liquid phases.

[0083] Optionally, it also includes a cantilever rotor device used in the turbocharger 3. The afterburner outlet 9 is connected to the turbocharger and can drive the turbine of the turbocharger 3 to do work. The turbocharger outlet 33 is connected to the engine air box. The engine air box is connected to the air inlet 14 of the afterburner 2. The starter motor 4 is connected to the turbocharger shaft through a coupling and transmits torque.

[0084] The cantilevered rotor assembly includes a shaft 33 and a radial turbine 34. The shaft 33 is arranged from front to back with a bearing 35, a centrifugal compressor impeller 36, an axial and radial damper 37, and a radial turbine 34.

[0085] The heat insulation sealing device 5 is located between the centrifugal compressor impeller and the radial turbine. One side of the centrifugal compressor impeller is connected to the bearing by end face fitting, and the other end face of the centrifugal compressor impeller is connected to the axial and radial damper. The bearing, centrifugal compressor impeller and axial and radial damper are pressed onto the shaft shoulder by the front nut to realize the assembly of the rotor system.

[0086] The centrifugal compressor impeller and radial turbine are arranged back-to-back, separated by axial and radial dampers and thermal insulation seals. The bearings are located at the front end of the shaft, supporting the entire rotor system, which is cantilevered. When the rotor system rotates at high speed, some of the air entering at the front end of the centrifugal compressor impeller is cooled by the bearings.

[0087] Meanwhile, the axial and radial dampers can generate axial and radial damping when the rotor system is running, dissipating rotor vibration energy; the axial end face of the axial and radial dampers forms a first small gap with the stationary part, and the radial outer cylindrical surface of the axial and radial dampers forms a second small gap with the stationary part; as the shaft rotates at high speed, the airflow in the first and second small gaps rotates and compresses at high speed, dissipating rotor vibration energy and ensuring stable operation of the cantilever rotor device.

[0088] The heat insulation sealing device is fixed to a stationary component and allows for internal ventilation, carrying away heat radiated and transferred from the combustion gas to achieve thermal isolation. The fit between the inner cylindrical surface of the heat insulation sealing device and the rotating shaft seals off high-pressure gas leaking from the dynamic-static interface. Furthermore, the fit between the inner cylindrical surface of the heat insulation sealing device and the outer cylindrical surface of the rotating shaft forms a third small gap. The high-speed rotation of the rotating shaft 1 drives the airflow within this third small gap to rotate at high speed, achieving a rotational seal and sealing off the high-pressure gas.

[0089] The gap width is related to the rotational speed and the pressure inside the disk cavity. Under the working conditions of 120,000-16,000 rpm and 1.1 standard atmospheres of pressure inside the disk cavity, the width of the first and second smallest gaps is 0.4mm-0.5mm, which can achieve a good vibration reduction effect.

[0090] The gap width between the inner cylindrical surface of the heat insulation sealing device and the outer cylindrical surface of the rotating shaft is related to the design speed and pressure. Under the working conditions of 120,000-16,000 rpm and 1.1 atmospheres of pressure, the width of the third smallest gap is 0.4mm-0.5mm, which can achieve a good effect of maintaining rotor stability.

[0091] In another aspect, the present invention provides a method of using an engine exhaust emission recirculation system, which specifically includes the following steps:

[0092] The first compressor (13) generates high-pressure gas, part of which flows into the burner of the afterburner through the gas valve (15), and the other part flows into the cylinder (4) of the engine (1) through the intercooler (16), forming a low-temperature high-pressure gas flow path of the circulation system; improving the working safety, reliability and component life of the cylinder, improving the quality and flow of the engine intake air, and improving the engine power.

[0093] Fuel in the fuel tank (2) enters the fuel pump (8) of the engine (1) through the first outlet, is pressurized, and then injected into the cylinder (4) of the diesel engine (1) through the fuel injector (9). It mixes and burns with the low-temperature, high-pressure gas from the intercooler (16), expands and does work to produce exhaust gas, which is discharged through the exhaust valve (7) of the engine (1) and enters the secondary combustion zone of the jet combustion chamber of the afterburner. In this process, the intercooler (16) reduces the temperature of the gas entering the engine (1), delays the injection time of the fuel injector (9) into the cylinder (4), and increases the fuel injection speed to suppress NO. X The generation of the gas; at the same time, the exhaust gas discharged from the engine (1) flows out through the exhaust valve (7) and is fully mixed and secondary burned with the high-temperature gas generated by the burner in the secondary combustion zone of the secondary combustion burner. This process converts the incompletely burned products such as HC, CO and PM in the exhaust gas of the engine (1) into harmless gases such as CO2 and H2O during the secondary combustion process.

[0094] The fuel in the fuel tank (2) enters the fuel injector (10) through the second outlet and is pressurized before entering the burner of the afterburner. After being fully mixed with the high-pressure gas from the gas valve (15), the fuel enters the secondary combustion zone of the jet afterburner's afterburner combustion chamber.

[0095] The high-temperature gas generated in the secondary combustion zone of the jet combustion chamber of the afterburner flows into the turbine (11) through the pipeline, expands and does work to generate energy, drives the compressor to compress and generate new high-pressure gas, which can increase the gas flow of the engine (1). At the same time, the turbine (11) drives the generator (12) to generate electricity and recover the remaining turbine energy.

[0096] When the second compressor 14 is installed, see [link to relevant documentation]. Figure 2 The air from the first compressor (13) enters the second compressor (14) for further compression. After two stages of compression, the high-pressure gas enters the combustion burner and the cylinder (4) of the diesel engine (1) through the air valve (15) and the intercooler (16).

[0097] When motor 17 is set, see [link / reference]. Figure 3The turbine and compressor of the circulating system operate independently. The turbine (11) drives the generator (12) to generate electricity for other equipment. The electric motor (17) drives the two-stage compressors 13 and 14 to generate high-pressure compression. During the cycle, part of the high-pressure gas provided by the first compressor (13) is supplied to the burner through the gas valve (15) to provide the high-pressure gas required for combustion. The remaining gas flows into the second compressor (14) for secondary compression and flows through the intercooler (16) into the cylinder (4) of the engine (1). This allows the large amount of unburned and harmful intermediate products contained in the exhaust gas discharged from the engine cylinder to be further burned, converting them into non-harmful gases and improving engine emissions. It also makes the turbine inlet conditions adjustable and controllable, which is beneficial to increasing the flexibility of turbocharger performance (speed, turbocharger and flow rate) adjustment. It alleviates the airflow blockage at the compressor outlet, which is beneficial to improving the compressor surge margin. At the same time, it can also recover exhaust gas energy. By adjusting the amount of electricity generated, the turbocharger compressor pressure can be controlled, abandoning the traditional exhaust valve adjustment method and improving the exhaust gas energy recovery efficiency.

[0098] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A diesel engine exhaust emission circulation system, comprising an engine, an oil tank, a supplemental combustion supercharging device, a turbine, a first air compressor, a gas valve and an intercooler, characterized in that, the engine comprises an air inlet valve, an exhaust valve and a fuel injector; the first air compressor is connected to the gas valve and the intercooler respectively; the gas valve is connected to the air inlet of the supplemental combustion supercharging device; the air inlet valve is connected to the intercooler; the fuel injector is connected to the oil tank; the exhaust valve is connected to the exhaust outlet of the supplemental combustion supercharging device; the outlet pipeline of the supplemental combustion supercharging device is connected to the turbine; the oil tank is connected to the fuel inlet of the supplemental combustion supercharging device; in use, the first air compressor generates high-pressure gas, part of which flows into the supplemental combustion supercharging device through the gas valve, and the other part of which flows into the cylinder of the engine through the intercooler, forming a low-temperature high-pressure gas flow path of the circulation system; the fuel in the oil tank is pressurized by the fuel pump of the engine and injected into the cylinder of the diesel engine through the fuel injector, mixed with the low-temperature high-pressure gas from the intercooler and burned, and then expanded to produce exhaust gas, which is discharged from the exhaust valve of the engine into the secondary combustion zone of the supplemental combustion supercharging device; the fuel in the oil tank is pressurized and then mixed with the high-pressure gas from the gas valve before entering the secondary combustion zone of the supplemental combustion supercharging device; the high-temperature gas generated in the secondary combustion zone of the combustor flows into the turbine to expand and do work to generate energy.

2. The diesel engine exhaust emission recirculation system of claim 1, wherein, It also includes a fuel injector, and the oil tank is connected to the fuel inlet of the supplemental combustion supercharging device through the fuel injector.

3. The diesel engine exhaust emission recirculation system of claim 1 wherein, It also includes a second air compressor, and the first air compressor is connected to the second air compressor; the high-pressure gas compressed by the first air compressor and the second air compressor enters the gas valve and the intercooler through the second air compressor.

4. The diesel engine exhaust emission recirculation system of claim 1 wherein, It also includes a generator, which is connected to the first air compressor or the second air compressor or the turbine.

5. The diesel engine exhaust emission recirculation system according to any one of claims 1-4, characterized in that, It also includes an electric motor, which is connected to the first air compressor, and a generator, which is connected to the turbine.

6. The diesel engine exhaust emission recirculation system of claim 1 wherein, The supplemental combustion supercharging device also includes an engine exhaust pipe, a turbocharger and a generator-motor integrated motor.

7. The diesel engine exhaust emission recirculation system of claim 1 wherein, The air entering the first air compressor is further compressed by the second air compressor, and the high-pressure gas after two-stage compression enters the supplemental combustion supercharging device and the cylinder of the engine through the gas valve and the intercooler respectively.

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