CN114483333A - Dual fuel engine test system and method - Google Patents

Abstract

The invention discloses a dual-fuel engine test system and method, which is applied to the technical field of internal combustion engine experiments, can realize switching of various engine operation modes, and can simulate different proportions of cracked mixed gas and ammonia and natural gas with different mixing ratios, so as to realize The performance test of the engine under different fuel conditions. The system includes a cracking gas simulation device for simulating mixed gases of different proportions produced by ammonia cracking; an ammonia gas generating device for generating ammonia; a natural gas generating device for generating natural gas; a fuel mixer, provided with a first fuel an input end and a first fuel output end; an electronic throttle valve, which is provided with an intake end of the electronic throttle valve and an outlet end of the electronic throttle valve; a fuel-air mixer, which is provided with a second fuel input end, a third fuel input end and a second fuel input end The output end; the engine is provided with an engine intake end and an engine exhaust end.

Description

Dual fuel engine test system and method

technical field

The invention relates to the technical field of internal combustion engine experiments, in particular to a dual-fuel engine test system and method.

Background technique

As the main source of power for the transportation industry, the engine has a serious problem of greenhouse gas emissions. Natural gas, as a low-carbon fuel, has been used in cars and ships. In addition, ammonia is widely considered as a carbon-free fuel as an alternative energy source of the future. The emission of greenhouse gases can be further reduced on the basis of the natural gas engine by mixing ammonia gas in the natural gas engine. However, due to the slower combustion speed of ammonia gas, the power of pure ammonia engine is lower. In the related art, some engines use the exhaust gas temperature to crack ammonia, but the ratio of the mixed gas after cracking is fixed, and it is difficult to realize switching between different fuels. Moreover, it is also difficult for the relevant engine test equipment to perform performance testing on the mixed combustion of pyrolysis gas and ammonia with different mixed gas ratios, as well as performance testing on the mixed combustion of dual fuels with different ratios.

SUMMARY OF THE INVENTION

In order to solve at least one of the above technical problems, the present invention proposes a dual-fuel engine test system and method, which can realize switching of various engine operating modes, and can simulate different proportions of cracked mixed gas and ammonia and natural gas with different mixing ratios , to realize the performance test of the engine under different fuel conditions.

On the one hand, an embodiment of the present invention provides a dual-fuel engine test system, including:

A pyrolysis gas simulation device, the pyrolysis gas simulation device is used to simulate mixed gases in different proportions produced by ammonia cracking;

An ammonia gas generating device, the ammonia gas generating device is used to generate ammonia gas;

a natural gas generating device for generating natural gas;

a fuel mixer, the fuel mixer is provided with a first fuel input end and a first fuel output end, and both the ammonia gas generating device and the natural gas generating device are connected to the first fuel input end;

an electronic throttle valve, the electronic throttle valve is provided with an electronic throttle valve intake end and an electronic throttle valve outlet end, the electronic throttle valve intake end is connected with the cracking gas simulation device, and the electronic throttle valve intake end An air inlet is provided on the connecting pipeline with the pyrolysis gas simulation device;

a fuel-air mixer, the fuel-air mixer is provided with a second fuel input end, a third fuel input end and a second fuel output end, the second fuel input end is connected with the air outlet end of the electronic throttle valve, the The third fuel input end is connected to the first fuel output end;

The engine is provided with an engine intake end and an engine exhaust end, the engine intake end is connected to the second fuel output end, and the engine exhaust end is used to discharge exhaust gas.

A dual-fuel engine test system provided according to an embodiment of the present invention has at least the following beneficial effects: simulating different proportions of cracked gas under different working conditions through a cracking gas simulation device, and mixing it with the ammonia gas output from the ammonia gas generating device in the fuel After mixing in the air mixer, it is input into the engine for combustion, thereby simulating different cracking products under different engine operating conditions, and realizing the engine mode with different proportions of cracked gas, so as to realize the test of engine performance with different proportions of cracked gas. At the same time, through the combined output of the ammonia gas generating device and the natural gas generating device, the amount of ammonia gas output by the ammonia gas generating device and the amount of natural gas output by the natural gas generating device are controlled, and the output ammonia gas and natural gas are mixed in the fuel mixer and then input to the fuel-air mixer After being mixed with air, the engine fuel is input to realize the dynamic change test of the mixed fuel of the engine under different mixing ratios of ammonia and natural gas. In addition, the working mode of pure ammonia or pure natural gas can also be realized by operating the ammonia gas generating device or the natural gas generating device alone, so as to realize multi-mode switching and performance test of the engine under different working modes.

According to some embodiments of the present invention, the ammonia gas generating device includes:

A liquid ammonia tank, which is used for storing liquid ammonia;

Ammonia mass flowmeter, the ammonia mass flowmeter is provided with a first ammonia inlet end and a first ammonia outlet end, and the first ammonia inlet end is connected to the liquid ammonia tank;

Ammonia flow controller, the ammonia flow controller is provided with a second ammonia inlet end and a second ammonia outlet end, the second ammonia inlet end is connected with the first ammonia outlet end, and the second ammonia outlet end The end is connected to the first fuel input end of the fuel mixer.

According to some embodiments of the present invention, the natural gas generating device includes:

an LNG tank for storing LNG;

a natural gas mass flowmeter, wherein the natural gas mass flowmeter is provided with a first natural gas inlet end and a first natural gas outlet end, and the first natural gas inlet end is connected to the liquefied natural gas tank;

a natural gas flow controller, the natural gas flow controller is provided with a second natural gas inlet end and a second natural gas outlet end, the second natural gas inlet end is connected to the first natural gas outlet end, and the second natural gas outlet end The end is connected to the first fuel input end of the fuel mixer.

According to some embodiments of the present invention, the pyrolysis gas simulation device includes:

A cracked gas mixer, the cracked gas mixer is provided with a cracked gas mixed inlet end and a cracked gas mixed output end;

a hydrogen tank for storing hydrogen;

A hydrogen mass flow controller, the hydrogen mass flow controller is provided with a first hydrogen gas inlet end and a first hydrogen gas outlet end, the first hydrogen gas inlet end is connected to the hydrogen tank, and the first hydrogen gas outlet end be connected with the mixed inlet end of the cracked gas;

a nitrogen tank, which is used to store nitrogen;

Nitrogen mass flow controller, the nitrogen mass flow controller is provided with a first nitrogen gas inlet end and a first nitrogen gas outlet end, the first nitrogen gas inlet end is connected to the nitrogen tank, and the first nitrogen gas outlet end be connected with the mixed inlet end of the cracked gas;

Ammonia gas mass flow controller, the ammonia gas mass flow controller is provided with a third ammonia gas inlet end and a third ammonia gas outlet end, and the third ammonia gas inlet end is connected to the first ammonia gas inlet. On the gas end and the pipeline of the liquid ammonia tank, a second ammonia gas branch is formed, and the third ammonia gas outlet end is connected with the mixed gas inlet end of the cracked gas;

A cut-off valve, the cut-off valve is arranged on the second ammonia branch, and the cut-off valve is used to control the on-off state of the second ammonia branch.

According to some embodiments of the present invention, the system further includes:

a turbocharger, the turbocharger is provided with a first turbine inlet end and a first turbine outlet end, the cracked gas simulation device is connected to the first turbine intake end, and is connected to the cracked gas simulation device A fresh air inlet is arranged on the pipeline between the device and the inlet end of the first turbine;

Intercooler, the intercooler is provided with an intercooler tank, the intercooler is provided with an intercooler intake end and an intercooler exhaust end, and the intercooler intake end is connected to the first turbine outlet end , the intercooler exhaust end is connected to the intake end of the electronic throttle valve, and the intercooler is used to cool the mixed gas output by the turbocharger; wherein the connection to the first ammonia intake end The pipeline with the liquid ammonia tank is arranged on the medium cold water tank.

According to some embodiments of the present invention, the turbocharger is further provided with a second turbine inlet end and a second turbine outlet end, the second turbine inlet end is connected to the engine exhaust end, and the first turbine inlet end is connected to the engine exhaust end. The second turbine outlet is used to discharge exhaust gas.

On the other hand, an embodiment of the present invention provides a dual-fuel engine test method, the method includes the following steps:

Obtaining an engine working mode; wherein, the engine working mode includes a pure natural gas mode, a mixed combustion mode of natural gas and ammonia gas, and a pure ammonia plus cracked gas or hydrogen mode;

According to the working mode of the engine, adjust the working state of the natural gas generating device, the cracking gas simulation device and the ammonia gas generating device; wherein, the adjusting the working state of the natural gas generating device, the cracking gas simulation device and the ammonia gas generating device includes:

When the engine operating mode is the pure natural gas mode, the load size of the engine is obtained; according to the load size, engine speed and excess air coefficient, the electronic throttle valve opening value is determined, and the electronic throttle valve opening is adjusted accordingly. Obtain the air pressure at the outlet end of the electronic throttle valve, and calculate the amount of fresh air according to the air pressure; calculate the air-fuel ratio of the engine according to the amount of fresh air; adjust the working state of the natural gas generating device according to the air-fuel ratio;

Or, when the engine working mode is the natural gas and ammonia mixed combustion mode, a preset natural gas and ammonia blending ratio is obtained; according to the preset natural gas and ammonia blending ratio, the natural gas generating device and the ammonia gas are adjusted The working state of the device occurs;

Or, when the working mode of the engine is pure ammonia plus cracked gas or hydrogen mode, obtain the preset working condition of the engine; control the engine to run under the idle speed condition; according to the preset working condition, according to the preset cracked gas Set the mass flow value of cracked gas with the fuel ratio; according to the preset ratio of cracked gas to fuel and the mass flow value of the cracked gas, adjust the natural gas generating device, the cracking gas simulation device and the ammonia gas generating device ; Determine that the idle speed operating condition is stable, and adjust the ammonia gas generating device according to the engine preset operating condition.

According to some embodiments of the present invention, before executing the step of acquiring the engine working mode, the method further includes the following steps:

Controlling the natural gas generating device to be turned on, and the ammonia gas generating device and the cracking gas simulation device to be turned off;

Controlling the engine to run in the idle speed condition, so that the engine runs in the idle speed condition for a first preset time period, and the coolant temperature of the engine is greater than or equal to the first preset temperature, and the engine oil The temperature is greater than or equal to the second preset temperature.

According to some embodiments of the present invention, after performing the step of adjusting the working states of the natural gas generating device, the cracked gas simulation device and the ammonia gas generating device according to the engine operating mode, the method further includes the following steps:

controlling the engine to operate in the idle speed condition;

Controlling the ammonia gas generating device to reduce the output of ammonia fuel, and controlling the natural gas generating device to increase the natural gas output;

It is determined that the engine operates under the idle speed condition for a second preset time period, and the engine is controlled to stop.

According to some embodiments of the present invention, adjusting the working states of the natural gas generating device and the ammonia gas generating device according to the preset natural gas and ammonia mixing ratio includes:

Controlling the ammonia gas pressure output by the ammonia gas generating device and the natural gas pressure output by the natural gas generating device are both stabilized at a preset pressure value;

According to the preset natural gas and ammonia mixing ratio, firstly adjust the opening value of the ammonia flow controller and the opening value of the natural gas flow controller;

Obtain the natural gas mass flow data detected in real time by the natural gas mass flowmeter and the ammonia gas mass flow data detected in real time by the ammonia mass flowmeter;

According to the natural gas mass flow data and the ammonia gas mass flow data, a second adjustment is performed on the opening value of the ammonia flow controller and the opening value of the natural gas flow controller.

Description of drawings

1 is a schematic diagram of a dual-fuel engine test system provided by an embodiment of the present invention;

FIG. 2 is a flowchart of a dual-fuel engine test method provided by an embodiment of the present invention.

Detailed ways

The embodiments described in the embodiments of the present application should not be regarded as limitations of the present application, and all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is understood that "some embodiments" can be the same or a different subset of all possible embodiments, and Can be combined with each other without conflict.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application, and are not intended to limit the present application.

In the context of the intensified global greenhouse effect, reducing greenhouse gas emissions has become a huge challenge facing human beings today. As the main source of power for the transportation industry, the engine emits serious greenhouse gases. Ammonia is widely regarded as a carbon-free fuel as an alternative energy source of the future. Mixing ammonia in natural gas engines can further reduce greenhouse gas emissions on the basis of natural gas engines. However, due to the slow combustion speed of ammonia gas, the power of pure ammonia engine is low. In the related art, ammonia is cracked by using the temperature of the exhaust gas, but the mixed gas generated after cracking is a gas component with a fixed ratio, and it is difficult to realize switching between different fuels. In addition, it is also difficult for related engine test equipment to simulate the mixed combustion of pyrolysis gas and ammonia with different mixed gas ratios and perform performance tests, and it is also difficult to detect the performance of dual-fuel mixed combustion with different ratios.

Based on this, the embodiment of the present invention provides a dual-fuel engine test system, which can realize switching of various engine operating modes, and can simulate different proportions of cracked mixed gas and ammonia and natural gas with different mixing ratios, so as to realize the operation of the engine in different fuels. case performance test.

1 , the dual-fuel engine test system provided by the embodiment of the present invention includes: a pyrolysis gas simulation device, an ammonia gas generator, a natural gas generator, a fuel mixer 104 , an electronic throttle valve 106 , a fuel-air mixer 107 , and an engine 108 . Specifically, the pyrolysis gas simulation device is used to simulate the mixed gas of different proportions produced by ammonia pyrolysis, that is, to provide the required proportion of pyrolysis gas for the test system. An ammonia gas generator was used to provide ammonia fuel for the test system. The natural gas generator is used to provide the required natural gas for the test system. Meanwhile, the fuel mixer 104 is provided with a first fuel input end and a first fuel output end. Wherein, both the ammonia gas generating device and the natural gas generating device are connected to the first fuel input end of the fuel mixer 104 . When the engine working mode is in the natural gas and ammonia mixed combustion mode, the ammonia gas output from the ammonia gas generating device and the natural gas output from the natural gas generating device are both input into the fuel mixer 104 for thorough mixing. In addition, the electronic throttle valve 106 is provided with an intake end of the electronic throttle valve and an outlet end of the electronic throttle valve. Wherein, the intake end of the electronic throttle valve is connected with the cracked gas simulation device. At the same time, an air inlet, that is, a fresh air inlet 114 , is provided on the connecting pipe between the intake end of the electronic throttle valve and the cracked gas simulation device. The fuel-air mixer 107 is provided with a second fuel input, a third fuel input, and a second fuel output. Wherein, the second fuel input end is connected with the electronic throttle output end, and the third fuel input end is connected with the first fuel output end. Accordingly, the engine 108 is provided with an engine intake end and an engine exhaust end, and the engine intake end is connected to the second fuel output end. The exhaust end of the engine is used to discharge the exhaust gas produced by combustion. When the engine works in the mode of pure ammonia plus cracked gas or hydrogen, by controlling the cracking gas simulation device to output the corresponding proportion of cracked gas or hydrogen, and controlling the ammonia generating device to output the required amount of ammonia, the cracked gas or hydrogen and ammonia and the The air entering the fresh air inlet 114 is mixed in the fuel-air mixer 107 and then fed into the engine 108 for combustion, so as to realize the combustion performance test of the mixture of cracked gas and ammonia under different mixed gas ratios. In addition, when the engine works in pure natural gas mode, the ammonia gas generating device and the cracked gas simulation device are turned off, and the natural gas generating device is turned on. At this point, the only fuel used in the system is natural gas. The natural gas output from the natural gas generating device passes through the fuel mixer 104 and then enters the fuel-air mixer 107 . Further, the amount of air input from the fresh air inlet 114 is controlled by the electronic throttle valve 106 to provide sufficient oxygen for natural gas combustion. After the natural gas and air are mixed in the fuel-air mixer 107, they are fed into the engine 108 for combustion.

In the working process of the above specific embodiment, by controlling the output of the cracking gas simulation device, the ammonia gas generating device and the natural gas generating device, the mixed combustion of ammonia gas and natural gas in different proportions, and the cracking gas and ammonia gas of different proportions of mixed gas are realized. Mixed combustion, and by changing the output of the cracked gas simulation device, the ammonia gas generating device and the natural gas generating device, the switching of different fuel modes of the engine 108 is realized, so that corresponding engine performance tests are performed under different fuel modes. Due to the slow combustion speed and low combustion efficiency of pure ammonia, it is necessary to add combustion accelerants such as pyrolysis gas or hydrogen when burning pure ammonia to alleviate the problem of slow combustion speed and low combustion efficiency of pure ammonia. When the engine working mode is pure ammonia plus cracked gas or hydrogen mode, first adjust the engine to run at idle speed. At this time, the engine has no load or a small load. Further, the cracked gas simulation device is turned on, and the amount of cracked gas and the total fuel is set according to a certain ratio according to the actual operating conditions to be tested by the engine 108 . Then, the output of the ammonia gas generator is controlled to gradually increase. When the idle speed condition is stable, according to the working condition set by the console, the supply of ammonia gas is gradually increased, so as to achieve the target test condition and complete the performance test of the target test condition. When the engine working mode is the mixed combustion mode of natural gas and ammonia, according to the test conditions set by the console, the natural gas output of the natural gas generator and the ammonia output of the ammonia generator are respectively controlled to achieve the set test conditions. After the mixing ratio, it runs stably, so as to realize the performance detection of the target test conditions. When the engine operating mode is the pure natural gas mode, the size of the load is set through the console, and the amount of fresh air input is controlled through the electronic throttle valve 106 . Further, according to the fuel-air ratio required by the engine, the natural gas output of the natural gas generating device is adjusted to ensure the supply of natural gas, so as to realize the performance detection of the target test condition.

1 , in some embodiments of the present invention, the ammonia gas generating device includes: a liquid ammonia tank 102 , an ammonia mass flow meter 222 , and an ammonia flow controller 232 . Specifically, the liquid ammonia tank 102 is used to store liquid ammonia. The ammonia mass flow meter 222 is provided with a first ammonia inlet end and a first ammonia outlet end. Wherein, the first ammonia inlet end is connected to the liquid ammonia tank 102 . Likewise, the ammonia flow controller 232 is provided with a second ammonia inlet end and a second ammonia outlet end. The second ammonia inlet end is connected to the first ammonia outlet end, and the second ammonia outlet end is connected to the first fuel input end of the fuel mixer 104 . The amount of ammonia output from the liquid ammonia tank 102 is detected by the ammonia mass flowmeter, and the opening of the ammonia flow controller is adjusted according to the detected amount of ammonia, so as to achieve more precise control of the output ammonia amount.

It should be noted that, referring to FIG. 1 , in some embodiments of the present invention, the ammonia gas generating device further includes an ammonia gas pressure reducing valve 201 and an ammonia regulator 212 . Specifically, the ammonia gas pressure reducing valve 201 is arranged on the connection pipeline between the ammonia mass flowmeter 222 and the liquid ammonia tank 102 , and the ammonia regulator 212 is arranged between the ammonia gas pressure reducing valve 201 and the ammonia mass flowmeter 222 . When the liquid ammonia tank 102 is opened, due to the large air pressure difference between the inside and the outside of the liquid ammonia tank 102, the output ammonia gas flow will be unstable, which affects the detection of the ammonia gas mass flow by the ammonia mass flowmeter. The ammonia gas output from the liquid ammonia tank 102 is decompressed through the ammonia gas pressure reducing valve 201, and then the ammonia gas flow pressure is further stabilized at a certain pressure value through the ammonia regulator 212, thereby improving the stability and reliability of the system sex.

Referring to FIG. 1 , in some embodiments of the present invention, the natural gas generating device includes: a liquefied natural gas tank 101 , a natural gas mass flow meter 221 , and a natural gas flow controller 231 . Specifically, the LNG tank 101 is used to store LNG. The natural gas mass flow meter 221 is provided with a first natural gas inlet end and a first natural gas outlet end, wherein the first natural gas inlet end is connected to the LNG tank 101 . The natural gas flow controller 231 is provided with a second natural gas inlet end and a second natural gas outlet end, the second natural gas inlet end is connected to the first natural gas outlet end, and the second natural gas outlet end is input with the first fuel of the fuel mixer 104 end connection. When the LNG tank 101 is opened, the natural gas mass flow rate output by the LNG tank 101 is detected by the natural gas mass flow meter 221, and the opening degree of the natural gas flow controller 231 is adjusted according to the detected natural gas mass flow value, so as to realize the natural gas flow control. The output is more precise control.

It should be noted that, referring to FIG. 1 , in some embodiments of the present invention, the natural gas generating device further includes: a natural gas pressure reducing valve 202 , a natural gas vaporizer 103 and a natural gas pressure regulator 211 . Specifically, the natural gas pressure reducing valve 202 is arranged on the connecting pipeline between the natural gas mass flow meter 221 and the LNG tank 101, the natural gas pressure regulator 211 is arranged between the natural gas pressure reducing valve 202 and the natural gas mass flow meter 221, and the natural gas vaporizer 103 It is arranged between the natural gas pressure reducing valve 202 and the natural gas pressure regulator 211 . Due to the large pressure difference between the inside and the outside of the LNG tank 101 , when the LNG tank 101 is opened, the output natural gas flow is unstable, which affects the detection of the natural gas mass flow by the natural gas mass flowmeter 221 . The natural gas output from the LNG tank 101 is decompressed through the natural gas pressure reducing valve 202 , and then the LNG output from the LNG tank 101 is vaporized relatively completely through the natural gas vaporizer 103 to reduce the residual LNG. Further, the natural gas regulator stabilizes the gas flow pressure at a certain pressure value, thereby improving the stability and reliability of the system.

1, in some embodiments of the present invention, the cracked gas simulation device includes: a cracked gas mixer 113, a hydrogen tank 112, a hydrogen mass flow controller 253, a nitrogen tank 111, a nitrogen mass flow controller 252, an ammonia gas mass Flow controller 251 and shut-off valve 110 . Specifically, the cracked gas mixer 113 is provided with a cracked gas mixed inlet end and a cracked gas mixed output end. The hydrogen tank 112 is used to store hydrogen. The hydrogen mass flow controller 253 is provided with a first hydrogen gas inlet end and a first hydrogen gas outlet end. The first hydrogen inlet end is connected to the hydrogen tank 112 , and the first hydrogen outlet end is connected to the cracked gas mixed inlet end. The amount of hydrogen output from the hydrogen tank 112 is controlled by the hydrogen mass flow controller 253 . In addition, the nitrogen tank 111 is used for storing nitrogen gas. The nitrogen mass flow controller 252 is provided with a first nitrogen gas inlet end and a first nitrogen gas outlet end, wherein the first nitrogen gas inlet end is connected to the nitrogen tank 111 , and the first nitrogen gas outlet end is connected to the pyrolysis gas mixed gas inlet end. The amount of nitrogen output from the nitrogen tank 111 is controlled more precisely by the nitrogen mass flow controller 252 . Meanwhile, the ammonia gas mass flow controller 251 is provided with a third ammonia gas inlet end and a third ammonia gas outlet end. Wherein, the third ammonia gas inlet end is connected to the pipeline connecting the first ammonia gas inlet end and the liquid ammonia tank 102 to form a second ammonia gas branch, and the third ammonia gas outlet end and the cracked gas mixed inlet end connect. The ammonia gas output on the second ammonia gas branch is controlled more precisely by the ammonia gas mass flow controller 251 on the second ammonia gas branch. Further, after the hydrogen, ammonia and nitrogen are input into the cracking gas mixer 113 in the required proportions and mixed evenly, the cracking gas of mixed gas in different proportions is simulated. In addition, a shut-off valve 110 is also provided on the second ammonia gas branch, and the on-off state of the second ammonia gas branch is controlled by setting the on-off state of the shut-off valve 110 . When the engine works in the mixed combustion mode of ammonia and natural gas, the pyrolysis gas simulation device is turned off, the shut-off valve 110 on the second ammonia branch is closed, and the ammonia gas can only pass through the ammonia mass flow meter 222 and the ammonia flow controller 232, and finally enter the fuel Mixer 104 mixes with natural gas.

It should be noted that, referring to FIG. 1 , in some embodiments of the present invention, the cracked gas simulation device further includes: a nitrogen pressure reducing valve 203 and a hydrogen pressure reducing valve 204 . Specifically, the nitrogen pressure reducing valve 203 is arranged between the nitrogen tank 111 and the nitrogen mass flow controller 252, and the nitrogen pressure reducing valve 203 relieves the pressure difference between the inside and the outside of the nitrogen tank 111, so that the nitrogen flow output by the nitrogen tank 111 is maintained stable . The hydrogen pressure reducing valve 204 is disposed between the hydrogen tank 112 and the hydrogen mass flow controller 253 , and the hydrogen pressure reducing valve 204 relieves the problem of excessive pressure of the hydrogen flow output from the hydrogen tank 112 .

Referring to FIG. 1 , in some embodiments of the present invention, the dual-fuel engine test system provided by the present invention further includes: a turbocharger 116 and an intercooler 105 . Specifically, the turbocharger 116 is provided with a first turbine inlet end and a first turbine outlet end. Wherein, the cracked gas simulation device is connected with the inlet end of the first turbine, and a fresh air inlet is provided on the pipeline connecting the cracked gas simulation device and the inlet end of the first turbine. Meanwhile, the intermediate cooler 105 is provided with an intermediate cold water tank 109 . Correspondingly, the intercooler is provided with an intercooled intake end and an intercooled exhaust end. The air intake end of the intercooler is connected to the air outlet end of the first turbine, and the exhaust end of the intercooler is connected to the air intake end of the electronic throttle valve. The high-temperature gas supercharged by the turbocharger is cooled by the intercooler 105, thereby improving the working efficiency of the engine. At the same time, the pipeline connecting the first ammonia inlet end and the liquid ammonia tank 102 is arranged on the intermediate cold water tank 109, and the liquid ammonia is vaporized by the high temperature cooling water in the intermediate cold water tank 109, so that there are no small droplets in the ammonia gas. At the same time, during the heat exchange process, the ammonia gas cools the cooling water in the intermediate cold water tank 109, and the cooling water cools the engine 108 through the engine water circuit, so that the engine 108 operates normally. Through preheating, the ammonia gas is fully vaporized to alleviate the problem of ammonia droplets mixed in the ammonia gas, and the temperature of the cooling water is reduced through the heat exchange process between the ammonia gas and the cooling water, so that the cooling water cools the engine 108 , to stabilize the operating temperature of the engine 108 .

It should be noted that, in some embodiments of the present invention, in addition to using the residual heat of the intermediate cold water tank 109 to realize the vaporization of the liquid ammonia, the liquid ammonia can also be heated by electric heating or the residual heat of the engine exhaust gas, thereby realizing the vaporization of the liquid ammonia.

Referring to FIG. 1 , in some embodiments of the present invention, the turbocharger is further provided with a second turbine inlet end and a second turbine outlet end. Specifically, the intake end of the second turbine is connected to the exhaust end of the engine, and the exhaust end of the second turbine is used to discharge exhaust gas. The exhaust gas after combustion of the engine 108 is output to the intake end of the second turbine through the exhaust end of the engine, and is discharged from the exhaust end of the second turbine.

It should be noted that, referring to FIG. 1 , in some embodiments of the present invention, the dual-fuel engine test system provided by the present invention further includes: a one-way valve. Specifically, the one-way valve includes: a first one-way valve 241 , a second one-way valve 242 , a third one-way valve 261 , a fourth one-way valve 262 and a fifth one-way valve 263 . The first check valve 241 is arranged between the natural gas flow controller 231 and the fuel mixer 104, the second check valve 242 is arranged between the ammonia flow controller 232 and the fuel mixer 104, and the third check valve 261 It is arranged between the ammonia gas mass flow controller 251 and the cracked gas mixer 113, the fourth check valve 262 is arranged between the nitrogen mass flow controller 252 and the cracked gas mixer 113, and the fifth check valve 263 is arranged between the hydrogen gas mass flow controller 252 and the cracked gas mixer 113. Between the mass flow controller 253 and the cracked gas mixer 113 . Through the setting of the one-way valve, the gas can only pass through in one direction, which alleviates the problem of gas backflow.

It should be noted that, referring to FIG. 1 , in some embodiments of the present invention, the dual-fuel engine test system provided by the present invention further includes: an exhaust gas detection system 115 and an oxygen sensor 117 . Specifically, the exhaust gas detection system 115 is disposed between the exhaust end of the engine and the intake end of the second turbine, and the exhaust gas detection system 115 detects and analyzes the exhaust gas of the engine 108 . In addition, the oxygen sensor 117 is disposed at the gas outlet end of the second turbine to detect the oxygen content at the gas outlet end of the second turbine.

It should be noted that, in some embodiments of the present invention, the ammonia flow controller 232 or the natural gas flow controller 231 includes a butterfly valve, or other types of flow control devices, such as a flow meter.

Referring to FIG. 2 , the embodiment of the present invention provides a dual-fuel engine test method, which can realize switching of various engine operating modes, and can simulate different proportions of cracked mixed gas and ammonia and natural gas with different mixing ratios, so as to realize different engine operating modes. Performance testing with fuel. The method in this embodiment of the present invention includes, but is not limited to, S310 and step S320.

Specifically, the process of applying this embodiment to the dual-fuel engine test system as shown in FIG. 1 includes the following steps:

S310: Obtain the engine working mode. Among them, the engine working modes include pure natural gas mode, natural gas and ammonia mixed combustion mode, and pure ammonia plus cracked gas or hydrogen mode.

S320: According to the working mode of the engine, adjust the working states of the natural gas generating device, the cracking gas simulation device and the ammonia gas generating device.

Among them, adjusting the working state of the natural gas generating device, the cracking gas simulation device and the ammonia gas generating device includes but is not limited to the following steps:

When the engine working mode is pure natural gas mode, obtain the load size of the engine; according to the load size, engine speed and excess air coefficient, determine the electronic throttle valve opening value, and adjust the electronic throttle valve opening value accordingly; obtain the electronic throttle valve outlet According to the air pressure, the fresh air volume is calculated; according to the fresh air volume, the air-fuel ratio of the engine is calculated; according to the air-fuel ratio, the working state of the natural gas generating device is adjusted.

Alternatively, when the engine working mode is the natural gas and ammonia mixed combustion mode, a preset natural gas and ammonia blending ratio is obtained; according to the preset natural gas and ammonia blending ratio, the working states of the natural gas generating device and the ammonia generating device are adjusted.

Or, when the engine working mode is pure ammonia plus cracked gas or hydrogen mode, the preset engine operating conditions are obtained; the engine is controlled to enter the idle speed operation; according to the preset operating conditions, the quality of the cracked gas is set according to the preset cracked gas and fuel ratio Flow value; according to the preset ratio of cracked gas to fuel and the mass flow value of cracked gas, adjust the natural gas generating device, the cracking gas simulation device and the ammonia gas generating device; determine the stable operation under the idle speed condition, and adjust the ammonia gas according to the preset working condition of the engine generating device.

In the working process of the above-mentioned specific embodiment, the working mode of the engine is first obtained through the console, and then the working states of the natural gas generating device, the cracking gas simulation device and the ammonia gas generating device are controlled according to the set working mode of the engine, so as to realize a variety of engines. Switch the working mode, and simulate the ammonia gas cracking products at different temperatures to realize the engine operation mode with different proportions of cracked gas, so as to test the effect of different proportions of cracked gas on the performance of the engine 108, and at the same time, realize different mixing ratios of ammonia and natural gas The experimental study to test the dynamic changes of the hybrid fuel. Specifically, the working modes of the engine include a pure natural gas mode, a mixed combustion mode of natural gas and ammonia gas, and a pure ammonia plus cracked gas or hydrogen mode. Correspondingly, when the engine operating mode is the pure natural gas mode, the load size of the engine 108 is obtained through the console. Further, the engine controller determines the opening value of the electronic throttle valve 106 according to the engine load, the rotational speed and the excess air coefficient value. At the same time, the air pressure at the outlet end of the electronic throttle valve is obtained, and the engine controller calculates the amount of fresh air according to the air pressure at the outlet end of the electronic throttle valve, and further, calculates the air-fuel ratio of the engine according to the amount of fresh air. According to the air-fuel ratio of the engine, the working state of the natural gas generating device is adjusted, so as to realize the operation of the engine in the pure natural gas mode. When the engine working mode is the natural gas and ammonia mixed combustion mode, the preset natural gas and ammonia mixing ratio is obtained through the console. According to the preset mixing ratio of natural gas and ammonia gas, the working states of the natural gas generating device and the ammonia gas generating device are adjusted. By adjusting the amount of natural gas output by the natural gas generator and the ratio of ammonia output by the ammonia generator, different mixing ratios of natural gas and ammonia can be achieved. After the natural gas and ammonia are mixed in the fuel mixer 104, they are mixed with the fuel-air mixer The air is mixed and then fed into the engine 108 for combustion, thereby realizing the operation of the engine in the mixed combustion mode of natural gas and ammonia gas. When the engine working mode is pure ammonia plus cracked gas or hydrogen mode, first obtain the engine preset working conditions through the console. Then, the engine 108 is controlled to run under the idle speed condition, and the mass flow value of the cracked gas is set according to the preset ratio of cracked gas to fuel according to the preset working condition. Further, according to the preset ratio of cracked gas to fuel and the mass flow value of the cracked gas, the output of the natural gas generating device, the cracking gas simulation device and the ammonia gas generating device is controlled. After it is determined that the current idle speed operating condition is stable, according to the engine preset operating condition set by the console, the ammonia gas output of the ammonia gas generating device is adjusted to achieve the target test operating condition. By adjusting and coordinating the working states of the natural gas generating device, the cracking gas simulation device and the ammonia gas generating device, a variety of engine operating modes can be switched, and different proportions of cracked mixed gas and ammonia and natural gas with different mixing ratios can be simulated. So as to realize the performance test of the engine under different fuel conditions.

It should be noted that, in some embodiments of the present invention, the simulated ammonia cracking products at different temperatures refer to mixed products generated by ammonia cracking reactions at different engine exhaust temperatures. When the engine is running under different operating conditions, the exhaust gas temperature of the engine will vary, and its variation range is about 250 to 450 degrees Celsius. At different temperatures, the concentration of the mixture components produced by the ammonia cracking reaction is different. By configuring the reformed products at different temperatures, the ammonia cracking products at different temperatures were simulated. That is: in the early stage, the temperature of the engine exhaust gas is obtained through the test, and then the concentration of each component in the ammonia cracking product is determined by the test. According to this concentration ratio, different cracked gas components are configured, and finally passed into the engine for combustion. Realize the simulation of ammonia cracking products at different temperatures, so as to test the effect of different proportions of cracked gas on engine performance.

In some embodiments of the present invention, before executing the step of acquiring the engine working mode, the dual-fuel engine test method provided by the embodiments of the present invention further includes but is not limited to the following steps:

Control the opening of the natural gas generating device, and the closing of the ammonia generating device and the pyrolysis gas simulation device.

The engine is controlled to run at idle speed, so that the engine runs at idle speed for a first preset duration, the coolant temperature of the engine is greater than or equal to the first preset temperature, and the oil temperature of the engine is greater than or equal to the second preset temperature.

During the working process of the above-mentioned specific embodiment, due to the slow combustion speed of ammonia fuel and the high ignition temperature, it is difficult to start the engine from cold. Therefore, the test system adopts pure natural gas mode during cold start. Specifically, the natural gas generating device is controlled to be turned on first, and the ammonia gas regeneration device and the cracked gas simulation device are controlled to be turned off. Further, the engine is controlled to enter the idle speed condition to run, when the engine runs in the idle speed condition for a first preset time period, and the coolant temperature of the engine is greater than or equal to the first preset temperature, and the oil temperature of the engine is greater than or equal to the second preset temperature. When the temperature is set, the engine cold start is completed. Exemplarily, firstly, the liquid ammonia tank 102 , the nitrogen tank 111 , and the hydrogen tank 112 are closed, the LNG tank 101 is opened, and the opening degree of the natural gas flow controller 231 is 10%. Then, the natural gas pressure is stabilized at 4 bar through the natural gas regulator 211. At this time, the speed of the engine 108 is set to 850r/min, and the engine 108 enters the idle speed operation. After running for 5 to 10 minutes, the engine coolant temperature is not lower than 60 ℃, and the oil temperature When the temperature is not lower than 45°C, the cold start of the engine is completed.

In some embodiments of the present invention, after performing the step of adjusting the working states of the natural gas generating device, the cracked gas simulating device and the ammonia gas generating device according to the engine working mode, the dual-fuel engine test method provided by the embodiments of the present invention also further Including but not limited to the following steps:

Control the engine to run at idle speed.

Control the ammonia gas generating device to reduce the output of ammonia fuel, and control the natural gas generating device to increase the natural gas output.

It is determined that the engine runs under the idle speed condition for a second preset time period, and the engine is controlled to stop.

During the working process of the above-mentioned specific embodiment, since ammonia gas has certain corrosiveness to metals, various sensitive detection devices are arranged in the engine. Therefore, it is necessary to gradually switch the fuel to pure natural gas between shutdowns, so as to alleviate the corrosion of detection equipment in the engine 108 caused by the residual ammonia gas. Specifically, firstly, the engine 108 is adjusted to run at idle speed, then the ammonia gas generating device is controlled to reduce the output of ammonia fuel, and the natural gas generating device is controlled to gradually increase the natural gas output. Finally, only natural gas is burned in the engine 108 . After it is determined that the engine 108 operates at the idle speed for a second preset time period, the engine 108 is controlled to stop. For example, the engine 108 is controlled to stop after 3 to 5 minutes of running the engine 108 at idle speed.

In some embodiments of the present invention, adjusting the working state of the natural gas generating device and the ammonia generating device according to the preset natural gas and ammonia mixing ratio, including but not limited to the following steps:

The pressure of ammonia gas output from the ammonia gas generating device and the natural gas pressure output from the natural gas generating device are controlled to be stable at preset pressure values.

According to the preset mixing ratio of natural gas and ammonia gas, the first adjustment is performed on the opening value of the ammonia flow controller and the opening value of the natural gas flow controller.

Obtain the natural gas mass flow data detected in real time by the natural gas mass flowmeter and the ammonia gas mass flow data detected in real time by the ammonia mass flowmeter.

According to the natural gas mass flow data and the ammonia gas mass flow data, a second adjustment is performed on the opening value of the ammonia flow controller and the opening value of the natural gas flow controller.

In the working process of the above-mentioned specific embodiment, firstly, the pressure of ammonia gas output by the ammonia gas reversion device and the pressure of natural gas output by the natural gas generating device are controlled to be stable at preset pressure values. Then, according to the preset mixing ratio of natural gas and ammonia gas, the opening value of the ammonia flow controller 232 and the opening value of the natural gas flow controller 231 are first adjusted. Further, the natural gas mass flow data detected by the natural gas mass flow meter 221 is acquired in real time, and at the same time, the ammonia gas mass flow data detected in real time by the ammonia mass flow meter 222 is acquired in real time. According to the natural gas mass flow data and the ammonia gas mass flow data, the second adjustment is made to the opening value of the ammonia flow controller 232 and the opening value of the natural gas flow controller 231, so that the mixing ratio of natural gas and ammonia reaches the preset mixing ratio. Mixing ratio, and stable operation. Exemplarily, the pressures of the two fuels are first stabilized at 4 bar by the ammonia regulator 212 and the natural gas regulator 211 . At this time, the ammonia flow controller 232 is gradually opened, and the opening degree of the natural gas flow controller 231 is reduced. Further, in order to ensure that the engine power does not fluctuate too much, the opening speed of the ammonia flow controller 232 is 2.5 times the decreasing speed of the natural gas flow controller 231 . The engine controller collects the readings of the natural gas mass flowmeter 221 and the ammonia mass flowmeter 222 for calculation. The engine controller feeds back and controls the opening of the ammonia flow controller 232 and the natural gas flow controller 231 according to the calculation results. The engine controller every 0.1 seconds Take the number once, until it reaches the set mixing ratio and runs stably.

The preferred implementation of the present invention has been specifically described above, but the present invention is not limited to the above-mentioned embodiments. Those skilled in the art can also make various equivalent deformations or replacements under the premise of not violating the spirit of the present invention. These Equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims (10)

1. a dual fuel engine test system, is characterized in that, comprises: A pyrolysis gas simulation device, the pyrolysis gas simulation device is used to simulate mixed gases in different proportions produced by ammonia cracking; An ammonia gas generating device, the ammonia gas generating device is used to generate ammonia gas; a natural gas generating device for generating natural gas; a fuel mixer, the fuel mixer is provided with a first fuel input end and a first fuel output end, and both the ammonia gas generating device and the natural gas generating device are connected to the first fuel input end; Electronic throttle valve, the electronic throttle valve is provided with an electronic throttle valve intake end and an electronic throttle valve outlet end, the electronic throttle valve intake end is connected with the cracking gas simulation device, and the electronic throttle valve intake end is connected with An air inlet is provided on the connecting pipeline of the pyrolysis gas simulation device; a fuel-air mixer, the fuel-air mixer is provided with a second fuel input end, a third fuel input end and a second fuel output end, the second fuel input end is connected with the air outlet end of the electronic throttle valve, the The third fuel input end is connected to the first fuel output end; The engine is provided with an engine intake end and an engine exhaust end, the engine intake end is connected to the second fuel output end, and the engine exhaust end is used to discharge exhaust gas. 2. The dual-fuel engine test system according to claim 1, wherein the ammonia gas generating device comprises: A liquid ammonia tank, which is used for storing liquid ammonia; Ammonia mass flowmeter, the ammonia mass flowmeter is provided with a first ammonia inlet end and a first ammonia outlet end, and the first ammonia inlet end is connected to the liquid ammonia tank; Ammonia flow controller, the ammonia flow controller is provided with a second ammonia inlet end and a second ammonia outlet end, the second ammonia inlet end is connected with the first ammonia outlet end, and the second ammonia outlet end The end is connected to the first fuel input end of the fuel mixer. 3. The dual-fuel engine test system according to claim 1, wherein the natural gas generating device comprises: an LNG tank for storing LNG; a natural gas mass flowmeter, wherein the natural gas mass flowmeter is provided with a first natural gas inlet end and a first natural gas outlet end, and the first natural gas inlet end is connected to the liquefied natural gas tank; a natural gas flow controller, the natural gas flow controller is provided with a second natural gas inlet end and a second natural gas outlet end, the second natural gas inlet end is connected to the first natural gas outlet end, and the second natural gas outlet end The end is connected to the first fuel input end of the fuel mixer. 4. The dual-fuel engine test system according to claim 2, wherein the cracked gas simulation device comprises: A cracked gas mixer, the cracked gas mixer is provided with a cracked gas mixed inlet end and a cracked gas mixed output end; a hydrogen tank for storing hydrogen; A hydrogen mass flow controller, the hydrogen mass flow controller is provided with a first hydrogen gas inlet end and a first hydrogen gas outlet end, the first hydrogen gas inlet end is connected to the hydrogen tank, and the first hydrogen gas outlet end be connected with the mixed inlet end of the cracked gas; a nitrogen tank, which is used to store nitrogen; Nitrogen mass flow controller, the nitrogen mass flow controller is provided with a first nitrogen gas inlet end and a first nitrogen gas outlet end, the first nitrogen gas inlet end is connected to the nitrogen tank, and the first nitrogen gas outlet end connected with the mixed gas inlet end of the cracked gas; Ammonia gas mass flow controller, the ammonia gas mass flow controller is provided with a third ammonia gas inlet end and a third ammonia gas outlet end, and the third ammonia gas inlet end is connected to the first ammonia gas inlet. On the gas end and the pipeline of the liquid ammonia tank, a second ammonia gas branch is formed, and the third ammonia gas outlet end is connected with the mixed gas inlet end of the cracked gas; A cut-off valve, the cut-off valve is arranged on the second ammonia branch, and the cut-off valve is used to control the on-off state of the second ammonia branch. 5. The dual-fuel engine test system according to claim 4, wherein the system further comprises: a turbocharger, the turbocharger is provided with a first turbine inlet end and a first turbine outlet end, the cracked gas simulation device is connected to the first turbine intake end, and is connected to the cracked gas simulation device A fresh air inlet is arranged on the pipeline between the device and the inlet end of the first turbine; Intercooler, the intercooler is provided with an intercooler tank, the intercooler is provided with an intercooler intake end and an intercooler exhaust end, and the intercooler intake end is connected to the first turbine outlet end , the intercooler exhaust end is connected to the intake end of the electronic throttle valve, and the intercooler is used to cool the mixed gas output by the turbocharger; wherein the connection to the first ammonia intake end The pipeline with the liquid ammonia tank is arranged on the medium cold water tank. 6 . The dual-fuel engine test system according to claim 5 , wherein the turbocharger is further provided with a second turbine inlet end and a second turbine outlet end, and the second turbine inlet end and The exhaust end of the engine is connected, and the exhaust end of the second turbine is used to discharge exhaust gas. 7. A dual-fuel engine test method, characterized in that the method comprises the following steps: Obtaining an engine working mode; wherein, the engine working mode includes a pure natural gas mode, a mixed combustion mode of natural gas and ammonia gas, and a pure ammonia plus cracked gas or hydrogen mode; According to the engine working mode, adjust the working states of the natural gas generating device, the cracking gas simulation device and the ammonia gas generating device; Wherein, the adjustment of the working state of the natural gas generation device, the cracked gas simulation device and the ammonia gas generation device includes: When the engine operating mode is the pure natural gas mode, the load size of the engine is obtained; according to the load size, engine speed and excess air coefficient, the electronic throttle valve opening value is determined, and the electronic throttle valve opening is adjusted accordingly. obtain the air pressure at the outlet end of the electronic throttle valve, and calculate the fresh air volume according to the air pressure; calculate the air-fuel ratio of the engine according to the fresh air volume; adjust the working state of the natural gas generating device according to the air-fuel ratio; Or, when the engine working mode is the natural gas and ammonia mixed combustion mode, a preset natural gas and ammonia blending ratio is obtained; according to the preset natural gas and ammonia blending ratio, the natural gas generating device and the ammonia gas are adjusted The working state of the device occurs; Or, when the working mode of the engine is pure ammonia plus cracked gas or hydrogen mode, obtain the preset working condition of the engine; control the engine to run under the idle speed condition; according to the preset working condition, according to the preset cracked gas Set the mass flow value of cracked gas with the fuel ratio; according to the preset ratio of cracked gas to fuel and the mass flow value of the cracked gas, adjust the natural gas generating device, the cracking gas simulation device and the ammonia gas generating device ; Determine that the idle speed operating condition is stable, and adjust the ammonia gas generating device according to the engine preset operating condition. 8. The dual-fuel engine test method according to claim 7, characterized in that, before executing the step of acquiring the engine operating mode, the method further comprises the following steps: Controlling the natural gas generating device to be turned on, and the ammonia gas generating device and the cracking gas simulation device to be turned off; Controlling the engine to run in the idle speed condition, so that the engine runs in the idle speed condition for a first preset time period, and the coolant temperature of the engine is greater than or equal to the first preset temperature, and the engine oil The temperature is greater than or equal to the second preset temperature. 9 . The dual-fuel engine test method according to claim 7 , wherein after performing the step of adjusting the working states of the natural gas generating device, the cracked gas simulation device and the ammonia gas generating device according to the engine operating mode. 10 . , the method also includes the following steps: controlling the engine to operate in the idle speed condition; Controlling the ammonia gas generating device to reduce the output of ammonia fuel, and controlling the natural gas generating device to increase the natural gas output; It is determined that the engine operates under the idle speed condition for a second preset time period, and the engine is controlled to stop. 10 . The dual-fuel engine test method according to claim 7 , wherein, according to the preset mixing ratio of natural gas and ammonia gas, adjusting the working states of the natural gas generating device and the ammonia gas generating device comprises: 10 . Controlling the ammonia gas pressure output by the ammonia gas generating device and the natural gas pressure output by the natural gas generating device are both stabilized at a preset pressure value; According to the preset natural gas and ammonia mixing ratio, firstly adjust the opening value of the ammonia flow controller and the opening value of the natural gas flow controller; Obtain the natural gas mass flow data detected in real time by the natural gas mass flowmeter and the ammonia gas mass flow data detected in real time by the ammonia mass flowmeter; According to the natural gas mass flow data and the ammonia gas mass flow data, a second adjustment is performed on the opening value of the ammonia flow controller and the opening value of the natural gas flow controller.

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