Intake passage liquid ammonia injection and exhaust gas recirculation heat recovery system and method

Abstract

The application discloses a kind of inlet passage liquid ammonia injection and exhaust gas circulation heat recovery system and method, it is related to the technical field of multi-fuel engine system, inlet passage liquid ammonia injection and exhaust gas circulation heat recovery system, comprising: liquid ammonia storage tank, liquid ammonia pressure stabilizing supply system, liquid ammonia nozzle, mixed heat exchanger, exhaust gas recirculation system and controller, controller calculates the real-time required liquid ammonia injection amount according to engine real-time working condition information and controls liquid ammonia nozzle work in real time, controller calculates the real-time required heat according to the real-time required liquid ammonia injection amount that liquid ammonia gasification and temperature rise to set temperature, according to the real-time required heat that liquid ammonia gasification and temperature rise to set temperature, calculate the real-time required exhaust gas, controller controls exhaust gas recirculation system according to real-time required exhaust gas amount and makes required amount of exhaust gas backflow into mixed heat exchanger.The application can improve engine system stability, improve engine efficiency, reduce pollutant emission.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of multi-fuel engine system, in particular to an intake port liquid ammonia injection and exhaust gas recirculation heat recovery system and method. BACKGROUND

[0002] As an engine fuel, ammonia gas faces the problems of difficult ignition, high ignition energy, long combustion duration, slow flame propagation speed, high emissions of unburned ammonia and nitrogen oxides. Among the many technical routes of multi-fuel engines, intake port injection of gaseous ammonia is the simplest technical route at present, but its fuel supply system is complex, requiring a large-volume gasification tank and a stable pressure and constant temperature control system. In addition, the liquefaction of ammonia gas is difficult to avoid in some operating conditions, which can easily cause failure and failure of the injection system. SUMMARY

[0003] The purpose of the present application is to provide an intake port liquid ammonia injection and exhaust gas recirculation heat recovery system and method to solve the problems existing in the prior art, improve the stability of the engine system, improve the efficiency of the engine and reduce pollutant emissions.

[0004] To achieve the above-mentioned purpose, the present application provides the following solutions:

[0005] The present application provides an intake port liquid ammonia injection and exhaust gas recirculation heat recovery system, comprising: a liquid ammonia storage tank, a liquid ammonia pressure supply system, a liquid ammonia nozzle, a mixing heat exchanger, an exhaust gas recirculation system and a controller, the liquid ammonia storage tank is used for storing liquid ammonia; the liquid ammonia pressure supply system is in communication with the liquid ammonia storage tank and regulates the pressure of the liquid ammonia discharged from the liquid ammonia storage tank to a set pressure; the liquid ammonia nozzle is in communication with the liquid ammonia pressure supply system and injects liquid ammonia at the set pressure into the mixing heat exchanger; the mixing heat exchanger provides a space for mixing liquid ammonia, exhaust gas and air; the exhaust gas recirculation system is used for recirculating the exhaust gas generated by the engine into the mixing heat exchanger; the controller calculates the real-time required liquid ammonia injection amount according to the real-time operating condition information of the engine and controls the operation of the liquid ammonia nozzle in real time, calculates the real-time required heat for the gasification and temperature rise of liquid ammonia to the set temperature according to the real-time required liquid ammonia injection amount, calculates the real-time required exhaust gas amount according to the real-time required heat for the gasification and temperature rise of liquid ammonia to the set temperature, and controls the exhaust gas recirculation system to recirculate the required amount of exhaust gas into the mixing heat exchanger according to the real-time required exhaust gas amount.

[0006] Preferably, the liquid ammonia pressure supply system comprises a liquid ammonia oil pump, a liquid ammonia pressure tank, a liquid ammonia low-pressure pump and a liquid ammonia medium-pressure pump connected in sequence by pipelines, and the liquid ammonia medium-pressure pump is in communication with the liquid ammonia nozzle.

[0007] Preferably, the liquid ammonia pressure stabilizing supply system further comprises a reflux heat exchanger, an oil return port of the liquid ammonia medium pressure pump is communicated with an inlet of a heat medium channel of the reflux heat exchanger, an outlet of the heat medium channel of the reflux heat exchanger is communicated with the liquid ammonia pressure stabilizing tank, and the liquid ammonia pressure stabilizing tank is communicated with the liquid ammonia storage tank through a pipeline provided with a pressure stabilizing regulating valve.

[0008] Preferably, the exhaust gas recirculation system comprises a main reflux pipeline, a first branch reflux pipeline and a second branch reflux pipeline, one end of the main reflux pipeline is communicated with an exhaust gas outlet of the engine, the other end is communicated with one end of the first branch reflux pipeline and one end of the second branch reflux pipeline, the other end of the first branch reflux pipeline is communicated with the mixing heat exchanger, the other end of the second branch reflux pipeline is communicated with an intake duct downstream of the mixing heat exchanger, a total exhaust gas valve is arranged on the main reflux pipeline, an exhaust gas mixing regulating valve is arranged on the first branch reflux pipeline, an exhaust gas straight-through regulating valve is arranged on the second branch reflux pipeline, the controller adjusts the total exhaust gas recirculation flow according to the engine working condition and the real-time combustion strategy, and then adjusts the opening degree of the total exhaust gas valve according to the total exhaust gas recirculation flow; the controller controls the opening degrees of the exhaust gas mixing regulating valve and the exhaust gas straight-through regulating valve in real time according to the real-time required exhaust gas amount to recirculate the required amount of exhaust gas into the mixing heat exchanger.

[0009] Preferably, an electric auxiliary heating device is arranged on the intake duct downstream of the mixing heat exchanger, and the controller controls the electric auxiliary heating device to heat the mixed gas in the intake duct downstream of the mixing heat exchanger to ensure that the gasification of liquid ammonia and the temperature of the intake duct meet the preset working condition requirements of the engine under cold engine and low load working conditions.

[0010] Preferably, a liquid ammonia flow meter is arranged on the pipeline between the liquid ammonia storage tank and the liquid ammonia oil pump; and a liquid ammonia pressure and temperature measuring meter is arranged on the pipeline between the liquid ammonia low pressure pump and the liquid ammonia medium pressure pump.

[0011] The application further provides an intake duct liquid ammonia injection and exhaust gas recirculation heat recovery method, which comprises the following steps:

[0012] The real-time required liquid ammonia injection amount is calculated according to the real-time working condition information of the engine, and the liquid ammonia injection nozzle is controlled in real time;

[0013] The real-time required heat for gasification and temperature rise of liquid ammonia to a set temperature is calculated according to the real-time required liquid ammonia injection amount;

[0014] The real-time required exhaust gas amount is calculated according to the real-time required heat for gasification and temperature rise of liquid ammonia;

[0015] The required amount of exhaust gas is recirculated into the mixing heat exchanger by the exhaust gas recirculation system in real time according to the real-time required exhaust gas amount.

[0016] Preferably, the total exhaust gas recirculation flow is determined according to the engine real-time working condition and real-time combustion strategy adjustment.

[0017] Preferably, the real-time required heat for liquid ammonia gasification and temperature rise is calculated by the following formula:

[0018]

[0019] In the formula, Q total is the total heat exchange amount; Q liquid is the heat exchange amount for liquid ammonia spray temperature rise; Q vap is the gasification heat amount; Q gas is the heat exchange amount for ammonia gas temperature rise; W a is the liquid ammonia mass flow; c p,l is the specific heat capacity of liquid ammonia; T b is the boiling point of liquid ammonia at the set pressure; T l,1 is the initial temperature of liquid ammonia spray; r a is the latent heat of ammonia gasification at the set pressure; c p,g is the specific heat capacity of ammonia gas; T g,2 is the final temperature of ammonia gas.

[0020] Preferably, in the cold engine and low load working condition, the electric auxiliary heating device is controlled to heat the mixed gas in the downstream intake passage of the mixed heat exchanger to ensure the gasification of liquid ammonia and the temperature of the intake passage to meet the preset working condition requirements of the engine.

[0021] The actual flow of the liquid ammonia nozzle is obtained, and the opening of the liquid ammonia nozzle is controlled according to the actual flow and the required liquid ammonia injection amount so that the actual flow is the same as the required liquid ammonia injection amount.

[0022] The present application has the following technical effects relative to the prior art:

[0023] The present application proposes to inject medium-pressure liquid ammonia into the mixed heat exchanger, and through the exhaust gas recirculation system, the gasification heat amount of ammonia gas can be ensured while the liquid ammonia injection is realized, and the mixed gas enters the cylinder after being fully mixed with air and is combusted to do work. The exhaust gas heat is used by the exhaust gas recirculation system to heat the directly-injected liquid ammonia, which promotes the full mixing of ammonia, air and part of the exhaust gas, helps to improve the active atmosphere in the engine cylinder, improves the ammonia ignition performance, and thus improves the engine efficiency and reduces pollutant emissions.

[0024] The present application realizes the applicability of liquid ammonia injection in cold start and multiple working conditions through the exhaust gas backflow and the electric auxiliary heating device.

[0025] The present application adjusts the injection pulse width of the liquid ammonia nozzle according to the engine working condition to realize the quantitative injection of liquid ammonia, and realizes the closed-loop control through the calculation or measurement of the actual flow of liquid ammonia to realize the real-time feedback, which has high responsiveness and applicability in variable working conditions. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the intake manifold liquid ammonia injection and exhaust gas recirculation heat recovery system and the engine provided in an embodiment of the present invention.

[0028] In the diagram: 1-Liquid ammonia storage tank; 2-Liquid tank heater; 3-Pressure stabilizing pipe regulating valve; 4-Vacuum safety valve; 5-Liquid ammonia reflux pump; 6-Reflux heat exchanger; 7-Reflux safety valve; 8-Liquid ammonia flow meter; 9-Liquid ammonia oil transfer pump; 10-Liquid ammonia pressure stabilizing tank; 11-Liquid ammonia low-pressure pump; 12-Liquid ammonia pressure and temperature measuring instrument; 13-Liquid ammonia medium-pressure pump; 14-Liquid ammonia nozzle; 15-Mixing heat exchanger; 16-Electric auxiliary heating device; 17-Engine; 18-Exhaust gas main valve; 19-Exhaust gas heat exchanger; 20-Exhaust gas direct flow regulating valve; 21-Exhaust gas mixing regulating valve. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] The fuel supply system of the existing ammonia gaseous injection technology route of the intake port is complex, and space shortage problems are prone to occur in actual application. The gasification of liquid ammonia in fuel supply needs to be completed before the injection system, and due to the limitation of the nozzle, the gas-liquid two-phase cannot be accepted, so the temperature and pressure control requirements of the gasification device are higher. Since the ammonia injection system usually also needs 5-8 bar of ammonia injection pressure, the temperature control system in this technology route needs to be always on to ensure that ammonia remains gaseous under special conditions of the engine (such as starting), which has great limitations in actual equipment application. On the other hand, since the amount of ammonia gas required by the engine under different conditions is not the same, the temperature control responsiveness of the supply system is high, and the ammonia gas temperature is prone to decrease at high flow rate, and the ammonia gas pressure is prone to be too high at low flow rate, both of which can cause ammonia liquefaction or the injection system to fail to accurately control the injection amount, thereby causing system failure.

[0032] Embodiments of the present application will be described below with reference to Figure 1

[0033] The present application provides an intake port liquid ammonia injection and exhaust gas heat recovery system, which is suitable for multi-fuel engines, such as ammonia-diesel dual-fuel engines, which comprises a liquid ammonia storage tank 1, a liquid ammonia pressure supply system, a liquid ammonia nozzle 14, a mixing heat exchanger 15, an exhaust gas recirculation system and a controller, the liquid ammonia storage tank 1 is used to store liquid ammonia; the liquid ammonia pressure supply system communicates with the liquid ammonia storage tank 1 and regulates the pressure of the liquid ammonia discharged from the liquid ammonia storage tank 1 to a set pressure; the liquid ammonia nozzle 14 communicates with the liquid ammonia pressure supply system and injects the liquid ammonia at the set pressure into the mixing heat exchanger 15; the mixing heat exchanger 15 provides a space for mixing liquid ammonia, exhaust gas and air; the exhaust gas recirculation system is used to return the exhaust gas generated by the engine 17 to the mixing heat exchanger 15; the controller calculates the real-time required liquid ammonia injection amount according to the real-time working condition information of the engine 17 and controls the operation of the liquid ammonia nozzle 14 in real time, the controller calculates the real-time required heat for the gasification and temperature rise of the liquid ammonia to the set temperature according to the real-time required liquid ammonia injection amount, calculates the real-time required exhaust gas amount according to the real-time required heat for the gasification and temperature rise of the liquid ammonia to the set temperature, and the controller controls the exhaust gas recirculation system to return the required amount of exhaust gas to the mixing heat exchanger 15 in real time according to the real-time required exhaust gas amount.

[0034] ​The present application proposes to inject medium-pressure liquid ammonia into the mixed heat exchanger 15, and through the exhaust gas recirculation system, the ammonia gasification heat demand can be ensured while realizing liquid ammonia injection, and after being fully mixed with air, it enters the cylinder for combustion and work. Through the exhaust gas recirculation system, the exhaust heat is used to heat the direct injection of liquid ammonia, promote the full mixing of ammonia, air and part of the exhaust gas, help to improve the engine 17 cylinder reaction active atmosphere, improve the ammonia ignition performance, and then improve the engine 17 efficiency and reduce pollutant emissions. In addition, the scheme provided by the present application avoids large gasification devices and avoids the problem of insufficient space in practical application.

[0035] In some embodiments, the liquid ammonia pressure stabilizing supply system includes a liquid ammonia oil pump 9, a liquid ammonia pressure stabilizing tank 10, a liquid ammonia low-pressure pump 11 and a liquid ammonia medium-pressure pump 13 connected in sequence through pipelines, and the liquid ammonia medium-pressure pump 13 is communicated with the liquid ammonia nozzle 14. The pressure range of the liquid ammonia output by the liquid ammonia low-pressure pump 11 is usually 10-15 bar, and the pressure range of the liquid ammonia output by the liquid ammonia medium-pressure pump 13 is usually greater than 15 bar.

[0036] In this embodiment, the gaseous ammonia can always be at the top of the liquid ammonia pressure stabilizing tank 10 by using gravity through the liquid ammonia pressure stabilizing tank 10, and the subsequent liquid outlet is at the bottom of the liquid ammonia pressure stabilizing tank 10 to ensure the liquid phase supply of ammonia. At the same time, the liquid ammonia pressure stabilizing tank 10 has a buffer safety function. When the pressure in the tank is higher than the preset value of the emptying safety valve under abnormal working conditions, the pressure of the stabilizing tank can be reduced through the top exhaust, and the engine 17 is stopped at the same time to check the fault. The supply pressure of the liquid ammonia can be controlled to be above 10 bar through the liquid ammonia pressure stabilizing tank 10 to ensure that the ammonia exists in liquid form under most environmental temperatures, and an initial pressure is provided for the subsequent fuel supply. The setting of two-stage pumping can reduce the pressure difference of the low-pressure pump and the medium-pressure pump. It can be understood that multi-stage pumping is used to improve the liquid ammonia injection pressure, and this way is considered in view of the corrosion and gasification of liquid ammonia. If one-stage pumping is used, gasification may occur to cause pump failure when the working condition changes (i.e. when the liquid ammonia flow changes greatly). Multi-stage pumping helps to reduce the pressure difference of each stage of pumping and improve the stability of the whole system.

[0037] In this embodiment, the liquid ammonia pressure stabilizing supply system first ensures the stable operation of the liquid ammonia nozzle 14 through multi-stage pressure pumps, and at the same time, the liquid ammonia pressure stabilizing tank 10 is arranged in the middle to ensure the ammonia supply pressure and remove gas, ensuring the liquid single-phase supply of the liquid ammonia pressure stabilizing supply system. Then, the liquid ammonia intake port injection is realized through the pulse width calibration and pressure control of the liquid ammonia nozzle 14. The liquid ammonia is directly injected into the mixed heat exchanger 15, heated by the heat from the exhaust gas recirculation while being mixed with the intake air, and ensures the gasification while realizing the homogeneous mixing of the intake air through the mixing of the three fluids, and then enters the engine 17 system for combustion and work. Figure 1 In this embodiment, the right side of the mixed heat exchanger 15 is the air intake port.

[0038] In some embodiments, the liquid ammonia pressure stabilizing supply system further comprises a reflux heat exchanger 6, the oil return port of the liquid ammonia medium pressure pump 13 is communicated with the heat medium channel inlet of the reflux heat exchanger 6, the heat medium channel outlet of the reflux heat exchanger 6 is communicated with the liquid ammonia pressure stabilizing tank 10, and the liquid ammonia pressure stabilizing tank 10 is communicated with the liquid ammonia storage tank 1 through a pipeline provided with a pressure stabilizing regulating valve.

[0039] The embodiment recovers the heat of the refluxed liquid ammonia, thereby avoiding heat loss.

[0040] In some embodiments, the exhaust gas recirculation system comprises a main reflux pipeline, a first branch reflux pipeline and a second branch reflux pipeline, one end of the main reflux pipeline is communicated with the tail gas exhaust port of the engine 17, the other end is communicated with one end of the first branch reflux pipeline and one end of the second branch reflux pipeline, the other end of the first branch reflux pipeline is communicated with the mixing heat exchanger 15, the other end of the second branch reflux pipeline is communicated with the intake duct downstream of the mixing heat exchanger 15, the main reflux pipeline is provided with an exhaust gas total valve 18, the first branch reflux pipeline is provided with an exhaust gas mixing regulating valve 21, the second branch reflux pipeline is provided with an exhaust gas direct regulating valve 20, the controller adjusts the total exhaust gas recirculation flow according to the engine 17 working condition and the real-time combustion strategy, and then adjusts the opening degree of the exhaust gas total valve 18 according to the total exhaust gas recirculation flow, and the controller controls the opening degrees of the exhaust gas mixing regulating valve 21 and the exhaust gas direct regulating valve 20 in real time according to the real-time required exhaust gas amount to recirculate the required amount of exhaust gas into the mixing heat exchanger 15.

[0041] The exhaust gas recirculation system in the embodiment divides the total exhaust gas recirculation flow into two paths, one path is introduced into the mixing heat exchanger 15 to heat and gasify the liquid ammonia spray and raise the temperature, and the other path is directly introduced into the intake duct downstream of the mixing heat exchanger 15, which is directly communicated with the air inlet of the engine 17, and the embodiment can realize that the exhaust gas recirculation flow meets the standard and avoids the safety hazard caused by excessive exhaust gas flow in the mixing heat exchanger 15.

[0042] In some embodiments, the downstream intake duct of the mixing heat exchanger 15 is provided with an electric auxiliary heating device 16, and in the cold start and low load working condition, the controller controls the electric auxiliary heating device 16 to heat the mixed gas in the downstream intake duct of the mixing heat exchanger 15 to ensure that the gasification of the liquid ammonia and the temperature of the intake duct meet the preset working condition requirements of the engine 17.

[0043] The embodiment of the application realizes the applicability of the liquid ammonia injection in cold start and multiple working conditions through the exhaust gas recirculation and the electric auxiliary heating device 16.

[0044] In some embodiments, a liquid ammonia flow meter 8 is arranged on the pipeline between the liquid ammonia storage tank 1 and the liquid ammonia delivery pump 9; and a liquid ammonia pressure temperature meter 12 is arranged on the pipeline between the liquid ammonia low-pressure pump 11 and the liquid ammonia medium-pressure pump 13.

[0045] In this embodiment, the controller calculates the actual injection amount of the liquid ammonia nozzle 14 according to the liquid ammonia pressure and temperature measured by the liquid ammonia pressure temperature meter 12 and the working state of the liquid ammonia medium-pressure pump 13, and controls the opening degree of the liquid ammonia nozzle 14 by comparing the actual injection amount of the liquid ammonia nozzle 14 with the required liquid ammonia injection amount so as to make the actual injection amount equal to the required liquid ammonia injection amount.

[0046] The present application adjusts the injection pulse width of the liquid ammonia nozzle 14 according to the working condition of the engine 17 to realize quantitative injection of liquid ammonia, and realizes closed-loop control through calculation or measurement of the actual flow of liquid ammonia for real-time feedback, which has high responsiveness and applicability in variable working conditions. The present application specifically obtains the engine working condition through communication with the diesel control.

[0047] In some embodiments, the liquid ammonia pressure regulating supply system further comprises a pressure regulating pipe regulating valve 3, an emptying safety valve 4, a liquid ammonia backflow pump 5, a backflow safety valve 7, and a liquid ammonia flow meter 8.

[0048] The present application also provides an air intake passage liquid ammonia injection and exhaust gas heat recovery method, which comprises:

[0049] The real-time required liquid ammonia injection amount is calculated according to the real-time working condition information of the engine 17, and the liquid ammonia nozzle 14 is controlled in real time;

[0050] The real-time required heat for gasification and temperature rise of liquid ammonia to a set temperature is calculated according to the real-time required liquid ammonia injection amount; specifically, the required heat for gasification and heating of liquid ammonia spray to a specified temperature can be obtained through calculation and database query;

[0051] The real-time required exhaust gas amount is calculated according to the real-time required heat for gasification and temperature rise of liquid ammonia; specifically, the required exhaust gas flow in the mixing heat exchanger 15 can be determined by table lookup according to the heat required for gasification and temperature rise of liquid ammonia spray and the temperature data of the exhaust port of the engine 17.

[0052] The required amount of exhaust gas is recirculated to the mixing heat exchanger 15 by the exhaust gas recirculation system in real time according to the real-time required exhaust gas amount.

[0053] The method for liquid ammonia injection in an air inlet channel and waste heat recovery provided by the embodiment of the application can abandon the existing large gasification device, and can realize liquid ammonia injection by pressure adjustment of a liquid ammonia pressure supply system. The liquid ammonia spray injected out is gasified and heated by the heat in the waste gas, the waste gas can improve the cylinder combustion model, improve the combustion efficiency, and further improve the engine efficiency.

[0054] In some embodiments, the total exhaust gas recirculation flow is determined according to the real-time working condition and real-time combustion strategy adjustment of the engine.

[0055] The method for determining the total exhaust gas recirculation flow in the embodiment belongs to a conventional technology. Specifically, the exhaust gas recirculation flow should be determined according to the engine speed, load, ammonia energy ratio, diesel injection working condition and other parameters.

[0056] In some embodiments, the real-time required heat for liquid ammonia gasification and temperature rise is calculated by the following formula:

[0057]

[0058] In the formula, Q total is the total heat exchange amount; Q liquid is the liquid ammonia spray temperature rise heat exchange amount; Q vap is the gasification heat; Q gas is the ammonia gas temperature rise heat exchange amount; W a is the liquid ammonia mass flow; c p,l is the specific heat capacity of liquid ammonia; T b is the boiling point of liquid ammonia at the set pressure; T l,1 is the initial temperature of the liquid ammonia spray; r a is the ammonia gasification latent heat at the set pressure; c p,g is the specific heat capacity of ammonia gas; T g,2 is the final temperature of ammonia gas.

[0059] Therefore, the total heat exchange amount includes the liquid ammonia spray temperature rise heat exchange amount, the gasification heat and the ammonia gas temperature rise heat exchange amount.

[0060] In some embodiments, under the cold engine and low load working condition, the electric auxiliary heating device 16 is controlled to heat the mixed gas in the downstream air inlet channel of the mixed heat exchanger 15 to ensure that the gasification of the liquid ammonia and the temperature of the air inlet channel meet the preset working condition requirements of the engine 17.

[0061] The embodiment of the application realizes the applicability of liquid ammonia injection under cold start and multiple working conditions by the waste gas backflow and the electric auxiliary heating device 16.

[0062] In some embodiments, the actual flow of the liquid ammonia nozzle 14 is obtained, and the opening degree of the liquid ammonia nozzle 14 is controlled according to the actual flow and the required liquid ammonia injection amount so that the actual flow is the same as the required liquid ammonia injection amount.

[0063] In this embodiment, the controller calculates the actual spraying amount of the liquid ammonia nozzle 14 according to the liquid ammonia pressure and temperature measured by the liquid ammonia pressure and temperature gauge 12 and the working state of the liquid ammonia medium pressure pump 13, and controls the opening of the liquid ammonia nozzle 14 by comparing the actual spraying amount of the liquid ammonia nozzle 14 with the required liquid ammonia spraying amount so as to make the actual spraying amount equal to the required liquid ammonia spraying amount.

[0064] The present application adjusts the spraying pulse width of the liquid ammonia nozzle 14 according to the working condition of the engine 17 to realize quantitative spraying supply of the liquid ammonia, and realizes closed loop control by calculating or measuring the actual flow of the liquid ammonia to realize real-time feedback, which has high responsiveness and applicability in variable working conditions.

[0065] The principles and implementation manners of the present application are described by using specific examples in the present application, and the above embodiment is only used to help understand the method of the present application and its core idea; meanwhile, for the general skilled in the art, the specific implementation manners and application ranges will be changed according to the idea of the present application. In conclusion, the content of the present description should not be understood as the limitation of the present application.

Claims

1. An air intake liquid ammonia injection and exhaust gas recycle heat recovery system, characterized by: include: Liquid ammonia storage tank, used to store liquid ammonia; A liquid ammonia pressure stabilization supply system is connected to the liquid ammonia storage tank and regulates the pressure of the liquid ammonia discharged from the liquid ammonia storage tank to a set pressure; A liquid ammonia nozzle is connected to the liquid ammonia pressure stabilization and supply system and injects liquid ammonia at a set pressure into the mixing heat exchanger; A mixing heat exchanger provides a space for mixing liquid ammonia, exhaust gas, and air; An exhaust gas recirculation system is used to return exhaust gas generated by the engine to the mixing heat exchanger to heat the liquid ammonia injected into the mixing heat exchanger; The controller calculates the required liquid ammonia injection volume based on real-time engine operating information and controls the operation of the liquid ammonia nozzle in real time. The controller also calculates the heat required for liquid ammonia vaporization and heating to a set temperature based on the required liquid ammonia injection volume, and calculates the required exhaust gas volume based on the heat required for liquid ammonia vaporization and heating to the set temperature. The controller then controls the exhaust gas recirculation system to return the required amount of exhaust gas to the mixing heat exchanger. The liquid ammonia pressure stabilization supply system includes a liquid ammonia oil pump, a liquid ammonia pressure stabilization tank, a low-pressure liquid ammonia pump, and a medium-pressure liquid ammonia pump connected sequentially via pipelines. The medium-pressure liquid ammonia pump is connected to the liquid ammonia nozzle. The exhaust gas recirculation system includes a main return pipeline, a first branch return pipeline, and a second branch return pipeline. One end of the main return pipeline is connected to the engine... The engine's exhaust port is connected to the main return pipe, and the other end is connected to one end of the first branch return pipe and one end of the second branch return pipe. The other end of the first branch return pipe is connected to the mixing heat exchanger, and the other end of the second branch return pipe is connected to the downstream intake of the mixing heat exchanger. An exhaust gas master valve is installed on the main return pipe, an exhaust gas mixing regulating valve is installed on the first branch return pipe, and an exhaust gas direct flow regulating valve is installed on the second branch return pipe. The controller adjusts and determines the total exhaust gas recirculation flow rate according to the engine operating conditions and real-time combustion strategy, and then adjusts the opening of the exhaust gas master valve according to the total exhaust gas recirculation flow rate. The controller controls the opening of the exhaust gas mixing regulating valve and the exhaust gas direct flow regulating valve in real time according to the real-time required exhaust gas volume to return the required amount of exhaust gas to the mixing heat exchanger.

2. The gas inlet passage liquid ammonia injection and exhaust gas heat recovery system according to claim 1, characterized by: The liquid ammonia pressure stabilization supply system also includes a reflux heat exchanger. The oil return port of the liquid ammonia medium-pressure pump is connected to the inlet of the heat medium channel of the reflux heat exchanger. The outlet of the heat medium channel of the reflux heat exchanger is connected to the liquid ammonia pressure stabilization tank. The liquid ammonia pressure stabilization tank is connected to the liquid ammonia storage tank through a pipeline equipped with a pressure regulating valve.

3. The inlet duct liquid ammonia injection and exhaust heat recovery system of claim 1, wherein: An electric auxiliary heating device is installed on the downstream intake duct of the mixing heat exchanger. Under cold engine and low load conditions, the controller controls the electric auxiliary heating device to heat the mixed gas in the downstream intake duct of the mixing heat exchanger to ensure the vaporization of liquid ammonia and that the temperature of the intake duct meets the preset operating conditions of the engine.

4. The inlet duct liquid ammonia injection and exhaust heat recovery system of claim 1, wherein: A liquid ammonia flow meter is installed on the pipeline between the liquid ammonia storage tank and the liquid ammonia oil pump; a liquid ammonia pressure and temperature measuring meter is installed on the pipeline between the liquid ammonia low-pressure pump and the liquid ammonia medium-pressure pump.

5. A method of inlet passage liquid ammonia injection and exhaust gas recycle heat recovery, characterized by: The intake passage liquid ammonia injection and exhaust gas heat recovery system according to any one of claims 1-4, comprising: Calculating the real-time required liquid ammonia injection amount according to the real-time engine operating condition information and controlling the liquid ammonia nozzle in real time; Calculating the real-time required heat for liquid ammonia gasification and temperature rise to the set temperature according to the real-time required liquid ammonia injection amount; Calculating the real-time required exhaust gas amount according to the real-time required heat for liquid ammonia gasification and temperature rise; Controlling the exhaust gas recirculation system to return the required amount of exhaust gas to the mixing heat exchanger in real time according to the real-time required exhaust gas amount.

6. The gas inlet passage liquid ammonia injection and exhaust gas heat recovery method according to claim 5, characterized by: Determining the total exhaust gas recirculation flow according to the real-time engine operating condition and real-time combustion strategy adjustment.

7. The method of claim 5, wherein: The real-time heat required for ammonia gasification and temperature rise is calculated by the following formula: Where Q total is the total heat exchange; Q liquid is the heat exchange for liquid ammonia spray temperature rise; Q vap is the gasification heat; Q gas is the heat exchange for ammonia gas temperature rise; W a is the liquid ammonia mass flow; c p,l is the specific heat capacity of liquid ammonia; T b is the boiling point of liquid ammonia at the set pressure; T l,1 is the initial temperature of the liquid ammonia spray; r a is the ammonia gasification latent heat at the set pressure; c p,g is the specific heat capacity of ammonia gas; T g,2 is the final temperature of ammonia gas.

8. The method of claim 5, wherein: In cold engine and low load operating conditions, controlling the electric auxiliary heating device to heat the mixture in the downstream intake passage of the mixing heat exchanger to ensure the gasification of liquid ammonia and the temperature of the intake passage meet the engine preset operating condition requirements; Obtaining the actual flow of the liquid ammonia nozzle, and controlling the opening of the liquid ammonia nozzle according to the actual flow and the required liquid ammonia injection amount so that the actual flow is the same as the required liquid ammonia injection amount.

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