Mixer and ammonia and air mixing and preheating system for ammonia engine

Abstract

The present invention relates to the technical field of internal combustion engines. Disclosed are a mixer and an ammonia and air mixing and preheating system for an ammonia engine. The mixer comprises: a main flow channel and an annular flow channel, wherein the main flow channel is configured to circulate a first gas; and the annular flow channel is configured to circulate a second gas, the annular flow channel is sleeved outside the main flow channel, and a plurality of circumferentially distributed communication holes are provided between the main flow channel and the annular flow channel. Further provided in the present invention is an ammonia and air mixing and preheating system for an ammonia engine. The mixer provided in the present invention can effectively promote the mixing of ammonia and air, improve the uniformity of components of a mixture, and facilitate the multi-point ignition of ammonia in a cylinder. The ammonia and air mixing and preheating system for an ammonia engine can effectively utilize the heat energy of the exhaust gas and raise the temperature of part of the mixture, thereby improving the combustion efficiency in the cylinder.

Description

Ammonia and air mixing preheating system for mixer and ammonia engine TECHNICAL FIELD

[0001] The present application relates to the technical field of internal combustion engines, in particular to an ammonia and air mixing preheating system for a mixer and an ammonia engine. BACKGROUND

[0002] Ammonia, as a carbon-free fuel, has attracted much attention. Its combustion process does not produce carbon dioxide, making it a potential green alternative fuel. At the same time, ammonia has a series of advantages over hydrogen, such as high energy density, mature industrialization, and low storage and transportation cost. The application of ammonia fuel can significantly reduce carbon dioxide emissions in the traditional transportation and power fields. The development and promotion of ammonia fuel is one of the effective ways to achieve the double carbon goal.

[0003] Ammonia can be used as fuel to convert chemical energy into mechanical energy through an internal combustion engine, but it still faces many challenges compared to traditional internal combustion engines. The high ignition energy, slow flame propagation speed, and high nitrogen oxide emissions of ammonia limit its clean and efficient combustion in the engine cylinder. The main combustion organization technology of ammonia engine currently uses high-activity fuels such as hydrogen, methane, and diesel to improve the in-cylinder combustion performance of ammonia. At this time, ammonia gas is injected into the cylinder from the intake port, and the mixing degree and flow characteristics of ammonia and air will directly affect the ammonia distribution in the engine cylinder. Incomplete ammonia combustion will occur due to uneven mixing, and the current mainstream ammonia fuel supply method is single-point injection in the intake port. The design of the mixer and the organization of the mixed gas have a significant impact on the combustion of the ammonia engine.

[0004] Therefore, there is an urgent need to provide a new scheme to improve the overall performance of ammonia fuel engine.

[0005] SUMMARY

[0006] The purpose of the present application is to provide an ammonia and air mixing preheating system for a mixer and an ammonia engine to solve the problems existing in the prior art and improve the overall performance of ammonia fuel engine.

[0007] To achieve the above-mentioned purpose, the present application provides the following scheme:

[0008] The present application provides a mixer, comprising: a main flow channel and an annular flow channel. The main flow channel is used for flowing a first kind of gas; the annular flow channel is used for flowing a second kind of gas, the annular flow channel is sleeved outside the main flow channel, and a plurality of communication holes distributed along the circumference are arranged between the main flow channel and the annular flow channel.

[0009] In an embodiment, the main flow channel has a first end for air intake and a second end for mixed gas outlet, the swirler and the swirler driving device are arranged in the main flow channel between the annular flow channel and the first end, and the swirler driving device is capable of controlling the rotating direction and power of the swirler.

[0010] In an embodiment, a plurality of inclined ribs are arranged on the inner wall of the main flow channel between the annular flow channel and the second end in a circumferential direction, and the inclined ribs extend along the direction of the mixed gas flow.

[0011] In an embodiment, the extension direction of the communication hole is tangential or chordal to the cylindrical structure in which the main flow channel is arranged.

[0012] The application further provides an ammonia-air mixing and preheating system for an ammonia engine, comprising a mixer and a preheating system. The mixer is used for mixing air and ammonia to form mixed gas, and the preheating system is used for preheating the mixed gas before discharging it into a combustion chamber. The mixer is the mixer described above.

[0013] In an embodiment, the preheating system comprises a heat exchanger and an electric heating module, and the heat exchanger and the electric heating module are arranged in sequence along the direction of the mixed gas flow, and the heat medium passage of the heat exchanger is in communication with the exhaust port of the combustion chamber.

[0014] In an embodiment, a controller is further included, which obtains the required heat Q mix of the mixed gas according to the intake air flow and ammonia flow corresponding to the engine operating condition, calculates the required current or voltage value of the electric heating module according to Q mix and controls the working state of the electric heating module in the initial starting stage, judges whether Q mix is greater than the maximum heat exchange capacity of the heat exchanger in the stable working stage, controls the electric heating module to work when Q mix is greater than the maximum heat exchange capacity of the heat exchanger, and calculates the required current or voltage value of the electric heating module according to Q mix and the maximum heat exchange capacity of the heat exchanger and controls the working state of the electric heating module.

[0015] In an embodiment, an electromagnetic valve is arranged in the gas path between the heat medium passage of the heat exchanger and the exhaust port of the combustion chamber, and the controller controls the opening degree of the electromagnetic valve in real time according to the required heat Q mix of the mixed gas.

[0016] In an embodiment, a nitrogen source and an air source are further included, which are communicated with the annular flow channel and the main flow channel of the mixer respectively, and a one-way valve, a first pressure sensor, an ammonia flow meter, a first electromagnetic valve, a first temperature sensor, an ammonia injection controller and a third pressure sensor are sequentially arranged between the nitrogen source and the annular flow channel.

[0017] An air flow meter, an exhaust turbocharger, a second temperature sensor and a second pressure sensor are sequentially arranged between the air source and the main flow channel, and a working channel of the exhaust turbocharger is communicated with an exhaust port of the combustion chamber.

[0018] In an embodiment, the controller adjusts the working state of the ammonia injection controller and the exhaust turbocharger according to the pressure value of the air detected by the second pressure sensor and the pressure value of the ammonia detected by the third pressure sensor in real time, and then adjusts the total air intake and the proportion of ammonia in the mixed gas in real time to match the target mixed gas amount of the ammonia engine.

[0019] The present application has the following technical effects compared with the prior art:

[0020] 1. The mixer provided by the present application can effectively promote the mixing of ammonia and air, improve the uniformity of the mixed gas, and improve the ignition and combustion performance of the in-cylinder mixed gas.

[0021] 2. The ammonia-air mixing and preheating system for ammonia engine provided by the present application can effectively utilize the exhaust heat energy to improve the temperature of part of the mixed gas, and then improve the combustion efficiency in the cylinder.

[0022] 3. The mixing and preheating system provided by the present application can accurately control the proportion of ammonia and air and adjust the flow parameters, can expand the operation boundary of the ammonia fuel engine, and adapt to the cycle switching of various working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Fig. 1 is a structural schematic view of the ammonia-air mixing and preheating system for ammonia engine provided by the embodiment of the present application.

[0025] Fig. 2 is a sectional view of the mixer provided by the embodiment of the present application.

[0026] The labels of the components are as follows: 1-ammonia source; 2-one-way valve; 3-first pressure sensor; 4-ammonia flow meter; 5-first electromagnetic valve; 6-first temperature sensor; 7-ammonia injection controller; 8-air source; 9-air flow meter; 10-waste gas turbocharger; 11-second temperature sensor; 12-second pressure sensor; 13-third pressure sensor; 14-vane control unit; 15-mixer; 16-heat exchanger; 17-third temperature sensor; 18-second electromagnetic valve; 19-electric heating module; 20-diesel supply module; 21-diesel injector; 22-combustion chamber; 151-main flow channel; 152-swirl vane; 153-communication hole; 154-annular flow channel; 155-inclined rib; 156-inlet. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0028] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0029] The present application provides a mixer 15, as shown in FIG. 2, comprising a main flow channel 151 and an annular flow channel 154.

[0030] The main flow channel 151 is used for flowing the first gas.

[0031] The annular flow channel 154 is used for flowing the second gas, the annular flow channel 154 is sleeved on the outside of the main flow channel 151, and a plurality of communication holes 153 distributed along the circumference are arranged between the main flow channel 151 and the annular flow channel 154.

[0032] When the mixer 15 in this embodiment is used for mixing ammonia and air, the ammonia can be introduced into the main flow channel 151 as the first gas, or can be introduced into the annular flow channel 154 as the second gas, both of which can improve the mixing effect of ammonia and air, and further improve the uniformity of the mixed gas, which is beneficial to the cylinder multi-point ignition of ammonia.

[0033] Of course, the embodiments of the present application are not limited to the ammonia and air mixing preheating system for ammonia engine, but can also be applied to other devices or systems that need to uniformly mix two gases.

[0034] In some embodiments, the embodiment of the present application further comprises the swirl vane 152 and the vane driving device, the first end of the main flow channel 151 is used for air inlet, the second end is used for mixed gas outlet, the swirl vane 152 is arranged in the main flow channel 151 between the annular flow channel 154 and the first end, and the vane driving device can control the rotating direction and power of the swirl vane 152.

[0035] The embodiment is used for regulating the turbulence degree of the air side in the mixer 15, thereby improving the mixing effect with the ammonia gas. Moreover, the mixed gas rotation direction can be adjusted by adjusting the vane rotating direction, so as to adjust the tumble ratio in the combustion chamber according to different combustion modes.

[0036] In some embodiments, a plurality of inclined ribs 155 are arranged on the inner wall of the main flow channel 151 between the annular flow channel 154 and the second end along the circumferential direction, and the inclined rib 155 extends along the direction of the mixed gas flow.

[0037] In the embodiment, the inclined flow channel is formed between the adjacent two inclined ribs 155, the mixed gas flows in the inclined flow channel to form the swirl flow, thereby strengthening the uniformity of the mixed gas.

[0038] The inclined rib 155 preferably extends along a spiral line, so as to enhance the swirl degree of the mixed gas.

[0039] In some embodiments, the extension direction of the communication hole 153 is the tangential direction or the chordal direction of the cylindrical structure where the main flow channel 151 is located.

[0040] In the embodiment, the ammonia gas enters the main flow channel 151 with a certain angle in the form of multiple-point tangential circle, thereby realizing that the ammonia gas and the air can still be fully mixed at a high flow rate.

[0041] The present application also provides an ammonia gas and air mixing preheating system for an ammonia engine, as shown in FIG. 1, comprising: a mixer 15 and a preheating system, the mixer 15 is used for mixing the air and the ammonia gas to form mixed gas; the preheating system is used for preheating the mixed gas before discharging the mixed gas into the combustion chamber 22; and the mixer is the mixer 15 as described in the above embodiments.

[0042] The embodiment has all the advantages of the mixer 15 provided in the above multiple embodiments, and will not be described here. In addition, the embodiment of the present application preheats the mixed gas, improves the temperature of the mixed gas, and improves the in-cylinder combustion efficiency.

[0043] In some embodiments, the preheating system comprises a heat exchanger 16 and an electric heating module 19; the heat exchanger 16 and the electric heating module 19 are sequentially arranged along the direction of the mixed gas flow, and the heat medium channel of the heat exchanger 16 and the exhaust port of the combustion chamber 22 are communicated.

[0044] The embodiment can effectively utilize the tail gas heat energy, save energy and protect the environment. The rear electric heating module 19 can perform secondary heating on the mixed gas. The device can adapt to various ammonia fuel supply states, so that the mixed preheating system has a wide use range for the ammonia fuel supply state, and can significantly improve the uniformity of the fuel gas, especially for the ammonia fuel supply state with gas-liquid two-phase.

[0045] In some embodiments, the heat exchanger 16 is internally arranged with multiple layers of U-shaped flow channels, which are in the form of upper and lower layers to distinguish the mixed gas and the engine exhaust gas and ensure sufficient heat exchange area therebetween. The exhaust gas flow entering the heat exchanger 16 is controlled in real time according to the engine exhaust gas temperature and the mixed gas flow.

[0046] The electric heating module 19 includes an internal pipeline and an electric heating wire. The internal pipeline is used for flowing the mixed gas, and the electric heating wire is embedded in the internal pipeline wall. The working current of the electric heating wire is controlled by an external controller, and the heating power of the electric heating wire is corrected according to the real-time calculated heat exchange amount, so that the temperature of the mixed gas at the outlet of the electric heating module 19 reaches the preset requirement, i.e., the target temperature.

[0047] In some embodiments, the embodiment of the application further includes a controller, which obtains the heat Q required for heating the mixed gas according to the intake air flow and the ammonia flow corresponding to the engine operating condition mix ; in the initial starting stage, the controller calculates the current or voltage value required for the electric heating module according to Q mix and controls the working state of the electric heating module; in the stable working stage, when Q mix is greater than the maximum heat exchange amount of the heat exchanger, the controller controls the electric heating module to work, and the controller calculates the current or voltage value required for the electric heating module according to Q mix and the maximum heat exchange amount of the heat exchanger and controls the working state of the electric heating module.

[0048] The working states of the heat exchanger and the electric heating module can be expressed by the following formula: when the heat required for heating the mixed gas is less than the heat exchange amount of the heat exchanger, the electric heating module does not work; otherwise, the electric heating module performs secondary heating on the mixed gas by controlling the voltage or current.

[0049] wherein Q mix is the heat flow required for heating the mixed gas, h is the convective heat transfer coefficient of the heat exchanger, A is the effective heat exchange area of the heat exchanger, T ex and T mix are the engine exhaust gas temperature and the initial mixed gas temperature, respectively, I and R are the current and resistance of the electric heating wire of the electric heating module, respectively, a is the opening degree of the exhaust gas solenoid valve, and Q loss is the heat loss of the electric heating module, which is a known value after the equipment is selected.

[0050] In addition, the application also provides another control mode of the electric heating module 19. In some embodiments, a third temperature sensor 17 is arranged on the gas path between the heat exchanger 16 and the electric heating module 19, the third temperature sensor 17 is used to detect the temperature of the mixed gas after preheating by the heat exchanger 16 and transmit to the controller, and the controller controls the working state of the electric heating module 19 in real time according to the temperature of the mixed gas. When the temperature is higher than the target temperature set by the controller, the electric heating module 19 is controlled to stop working, otherwise, the electric heating module 19 is controlled to work, and the working state of the electric heating module 19 is controlled according to the difference between the real-time temperature and the target temperature, so that the heated mixed gas can reach the target temperature.

[0051] In some embodiments, an electromagnetic valve is arranged on the gas path between the heat medium passage of the heat exchanger 16 and the exhaust port of the combustion chamber 22, and the controller controls the opening degree of the electromagnetic valve according to the heat Q mix The opening degree of the electromagnetic valve is controlled in real time.

[0052] In some embodiments, the embodiment of the application further comprises a nitrogen source and an air source 8, the nitrogen source and the air source 8 are communicated with the annular flow channel 154 and the main flow channel 151 of the mixer 15 respectively, and a one-way valve 2, a first pressure sensor 3, an ammonia flow meter 4, a first electromagnetic valve 5, a first temperature sensor 6, an ammonia injection controller 7 and a third pressure sensor 13 are arranged in sequence between the nitrogen source and the annular flow channel 154.

[0053] An air flow meter 9, an exhaust turbocharger 10, a second temperature sensor 11 and a second pressure sensor 12 are arranged in sequence between the air source 8 and the main flow channel 151, and the working channel of the exhaust turbocharger 10 is communicated with the exhaust port of the combustion chamber 22.

[0054] In some embodiments, the controller adjusts the working state of the ammonia injection controller 7 and the exhaust turbocharger 10 according to the real-time detection of the pressure value of the air by the second pressure sensor 12 and the real-time detection of the pressure value of the ammonia by the third pressure sensor 13, and then adjusts the total air intake and the proportion of ammonia in the mixed gas in real time, so as to match the target mixed gas amount of the ammonia engine.

[0055] The molar concentration C NH3 of ammonia in the mixed gas after mixing can be calculated by the following formula, wherein G NH3 and G air are the mass flow rates of ammonia and air respectively, and M NH3 and M air are the molar masses of ammonia and air respectively.

[0056] The implementation process of the ammonia gas and air mixing preheating system for ammonia engine provided by the above embodiments is as follows:

[0057] Fuel ammonia enters the mixing preheating system from the ammonia source 1, and the one-way valve 2 ensures the one-way flow of ammonia. The first pressure sensor 3 is used to detect the real-time ammonia pressure. When the engine enters the ammonia diesel running mode, the ammonia pressure is detected to see if it meets the pressure requirement of the ammonia injection controller 7. If not, the opening of the one-way valve 2 should be increased, and the pressure of the ammonia source 1 should be checked. After the ammonia pressure meets the requirement, the opening of the first electromagnetic valve 5 is controlled, and the ammonia enters the ammonia injection controller 7 through the ammonia flowmeter 4. The first temperature sensor 6 is used to detect the ammonia temperature and calculate the heat required by the mixing preheating system. The other air enters the exhaust turbocharger 10 through the air source 8 and the air flowmeter 9 to increase the intake air pressure and improve the air intake. The second temperature sensor 11 is used to detect the real-time air temperature and pressure. The ammonia and air enter the mixer 15 for gas mixing. The second pressure sensor 12 and the third pressure sensor 13 are respectively used to detect the air and ammonia intake pressure in real time. The working state of the ammonia injection controller 7 and the exhaust turbocharger 10 is adjusted to adjust the total intake and the proportion of ammonia in the mixed gas in real time, so as to match the target mixed gas amount of the ammonia engine. The mixed gas then enters the heat exchanger 16 for preliminary preheating. According to the target heating amount, the opening of the second electromagnetic valve 18 is controlled to introduce part of the exhaust gas into the heat exchanger 16 to heat the mixed gas. The third temperature sensor 17 is used to detect the mixed gas temperature at the outlet of the heat exchanger 16, and the working current of the electric heating module 19 is controlled. After two heating processes, the mixed gas enters the combustion chamber 22 for combustion. The diesel enters the cylinder through the diesel supply module 20 and the diesel injector 21 to control the injection strategy.

[0058] The principles and implementation modes of the present application are described by specific examples in the present application. The above examples are only used to help understand the method and core idea of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed. In summary, the content of the present application should not be understood as a limitation of the present application.

Claims

1. A mixer characterized by: It comprises: a main flow channel; for flowing a first gas; and an annular flow channel for flowing a second gas, the annular flow channel being sleeved on the outside of the main flow channel, and a plurality of communication holes being arranged along the circumference between the main flow channel and the annular flow channel.

2. The mixer of claim 1, wherein: It further comprises a swirl vane and a vane driving device, the first end of the main flow channel being used for air intake, the second end being used for mixed gas outlet, the swirl vane being arranged in the main flow channel between the annular flow channel and the first end, and the vane driving device being capable of controlling the rotation direction and power of the swirl vane.

3. The mixer of claim 2, wherein: A plurality of inclined ribs are arranged along the circumference on the inner wall of the main flow channel between the annular flow channel and the second end, the inclined ribs extending along the direction of the mixed gas flow.

4. The mixer of claim 1, wherein: The extension direction of the communication holes is tangential or chordal to the cylindrical structure where the main flow channel is located.

5. An ammonia gas and air mixing preheating system for an ammonia engine, characterized by: It comprises: a mixer for mixing air and ammonia gas to form mixed gas; and a preheating system for preheating the mixed gas before discharging it into a combustion chamber; The mixer is the mixer according to any one of claims 1-4. The preheating system comprises a heat exchanger and an electric heating module, the heat exchanger and the electric heating module being arranged in sequence along the direction of the mixed gas flow, and the heat medium channel of the heat exchanger being communicated with the exhaust port of the combustion chamber.

6. The ammonia gas and air mixing preheating system for ammonia engine according to claim 5, characterized by: It further comprises a nitrogen source and an air source, the nitrogen source and the air source being communicated with the annular flow channel and the main flow channel of the mixer respectively, and a one-way valve, a first pressure sensor, an ammonia gas flowmeter, a first electromagnetic valve, a first temperature sensor, an ammonia gas injection controller and a third pressure sensor being arranged in sequence between the nitrogen source and the annular flow channel; 7. The ammonia gas and air mixing preheating system for ammonia engine according to claim 6, characterized by: The controller obtains the heat Q required by the mixture according to the intake air flow and the ammonia flow corresponding to the engine working condition mix ; in the initial starting stage, the controller calculates the current or voltage value required by the electric heating module according to Q mix , and controls the working state of the electric heating module; in the working stable stage, the controller judges whether Q mix is greater than the maximum heat exchange capacity of the heat exchanger, and if yes, the controller controls the electric heating module to work, and the controller calculates the current or voltage value required by the electric heating module according to Q mix and the maximum heat exchange capacity of the heat exchanger, and controls the working state of the electric heating module.

8. The ammonia gas and air mixing preheating system for ammonia engine according to claim 7, characterized by: An electromagnetic valve is arranged on the gas path between the heat medium passage of the heat exchanger and the exhaust port of the combustion chamber, and the controller controls the opening of the electromagnetic valve according to the heat Q required for heating the mixture mix The electromagnetic valve is controlled in real time.

9. The ammonia gas and air mixing preheating system for ammonia engine according to claim 5, characterized by: An air flowmeter, an exhaust turbocharger, a second temperature sensor and a second pressure sensor are arranged in sequence between the air source and the main flow channel, and the working channel of the exhaust turbocharger being communicated with the exhaust port of the combustion chamber. The controller adjusts the working state of the ammonia gas injection controller and the exhaust turbocharger according to the real-time detection of the air pressure value by the second pressure sensor and the ammonia pressure value by the third pressure sensor, and then adjusts the total air intake and the proportion of ammonia in the mixed gas in real time, so as to match the target mixed gas amount of the ammonia engine.

10. The ammonia gas and air mixing preheating system for ammonia engine according to claim 9, characterized by: ​

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