Disclosure of Invention
The invention aims to provide an ammonia-hydrogen fuel engine based on a liquid ammonia thermal management supply system and an operation control method thereof, which can solve the problems of low energy efficiency, poor combustion effect of ammonia fuel and the like of the ammonia fuel engine.
The purpose of the invention is realized in the following way:
The invention discloses an ammonia-hydrogen fuel engine based on a liquid ammonia thermal management supply system, which is characterized by comprising an ammonia-hydrogen fuel engine, a heat recovery unit, a cooling unit and a turbocharger, wherein the turbocharger is connected between the ammonia-hydrogen fuel engine and the heat recovery unit, the ammonia-hydrogen fuel engine comprises an ammonia storage tank, a hydrogen storage tank, an ammonia fuel common rail pipe, an engine body, an ammonia return control valve bank and a mixer, the ammonia storage tank is connected with the ammonia fuel common rail pipe, the hydrogen storage tank is connected with a hydrogen gas rail through a hydrogen buffer tank, a cylinder, an ammonia fuel injector and an active pre-combustion chamber are respectively arranged in the engine body, the ammonia fuel injector and the active pre-combustion chamber are respectively connected with the cylinder, the ammonia fuel common rail pipe is connected with the ammonia fuel injector, the hydrogen gas rail is connected with the active pre-combustion chamber, the ammonia return control valve bank comprises a first electronic expansion valve and a third electronic expansion valve which are connected in parallel and are respectively connected with a second electronic expansion valve, the first electronic expansion valve and the third electronic expansion valve bank is respectively connected with a first electromagnetic three-way valve, the first electromagnetic three-way valve is connected with the ammonia buffer tank through the hydrogen buffer tank, the first electronic expansion valve is also connected with the hydrogen buffer pipe, and the hydrogen injector is also connected with the hydrogen buffer pipe.
The ammonia-hydrogen fuel engine based on the liquid ammonia thermal management supply system of the invention can further comprise:
1. The heat recovery unit comprises an SCR post-treatment device, a turbine, a steam turbine and a thermal cracker, waste heat discharged from the exhaust turbocharger is subjected to heat exchange through a second heat exchanger and then enters the SCR post-treatment device for emission, ammonia is converted into ammonia steam from a liquid state after being absorbed by the second heat exchanger, the ammonia enters the turbine for expansion and conversion into mechanical energy for output, ammonia entering the heat recovery unit is converted into gaseous ammonia after being absorbed by a third heat exchanger for overheating, the gaseous ammonia enters the thermal cracker through a three-way valve to decompose the ammonia into nitrogen and hydrogen, the hydrogen enters a hydrogen storage tank to serve as pilot fuel, and the hydrogen enters the SCR post-treatment device through the three-way valve, and the exhaust gas generated by the cracker is converted into shaft work through the turbine coaxial with the steam turbine and then is emitted.
2. The cooling unit comprises a first radiator, a second radiator, a lubricating oil tank, a water tank, a cooling water pump and a lubricating oil pump, wherein the two ends of the first radiator are respectively connected with the water tank and the cooling water pump, the water tank is connected with an engine cooling water inlet, the cooling water pump is connected with an engine cooling water outlet, the two ends of the second radiator are respectively connected with the lubricating oil tank and the lubricating oil pump, and the lubricating oil tank and the lubricating oil pump are both connected with an ammonia-hydrogen fuel engine.
The invention relates to an operation control method of an ammonia-hydrogen fuel engine based on a liquid ammonia thermal management supply system, which is characterized in that when the engine is started, a liquid ammonia supply unit supplies liquid ammonia fuel to an ammonia fuel common rail pipe and an in-cylinder direct injection device of the ammonia fuel, hydrogen fuel is used as ignition and combustion-supporting fuel of the ammonia fuel, an ammonia fuel cracker does not work at the moment, the hydrogen fuel is operated through hydrogen stored in a hydrogen storage tank, part of the hydrogen fuel is supplied to an in-cylinder injection device, jet ignition is performed to inject the ammonia fuel into a cylinder after ignition, and the other part of the jet ignition is introduced into a combustion chamber through an air inlet channel to support combustion.
The operation control method of the ammonia-hydrogen fuel engine based on the liquid ammonia thermal management supply system of the invention can further comprise the following steps:
1. When the engine is operated, liquid ammonia supplied by the liquid ammonia supply assembly enters the in-cylinder injection device after overheat control is completed, another part of ammonia fuel is gasified into ammonia gas, then enters the multi-stage heat recovery assembly, the ammonia cracker and the SCR aftertreatment device, waste gas heat energy of the internal combustion engine provides energy for ammonia in the ammonia cracker to be cracked and the SCR aftertreatment device, the ammonia cracker operates in the operation process, hydrogen generated after the ammonia cracking reaction meets the requirement of the internal combustion engine, and meanwhile, additional waste gas is subjected to shaft work compensation through a turbine, if the hydrogen fuel meets the use requirement at the moment, the supply of the hydrogen supply assembly is stopped, the fuel in-cylinder injection device supplies and injects hydrogen, ammonia gas and nitrogen gas mixture generated after the ammonia cracking reaction into a cylinder of the ammonia-hydrogen internal combustion engine through the hydrogen storage tank, and meanwhile, the hydrogen gas mixture enters a combustion chamber through a mixer of an air inlet channel as combustion-supporting fuel of ammonia.
The invention has the advantages that:
1. The invention realizes the high-efficiency coupling of the waste heat utilization of the ammonia-hydrogen engine, fully utilizes the waste heat energy of the engine, improves the energy utilization efficiency and completes the carbonization-free emission of the system.
2. The invention adopts the liquid ammonia fuel supply, the direct injection supply and the injection mode in the cylinder, and simultaneously realizes the coupling of two injection modes taking the air inlet channel injection as the auxiliary by controlling the ammonia return, combines the ignition and combustion-supporting functions of hydrogen fuel, strengthens the combustion in the cylinder of the engine and realizes the multi-working-condition adjustable injection mode.
3. The ammonia hydrogen fuel engine supply system is subjected to overheat control through the heat recovery unit, so that the inherent attribute defect problems of low ammonia fuel combustion speed and high ignition point are solved, the combustion speed is improved, the heat efficiency is improved, and meanwhile, the multiple injection requirements of the engine are met.
4. The heat recovery unit is used for recovering and utilizing the waste heat of the engine in a multistage manner, so that the compensation of the shaft work of the waste heat of the engine is realized, and the ammonia gas is overheated in a multistage manner, so that the ammonia gas can meet the energy requirements of the thermal cracker and the SCR aftertreatment device.
5. Compared with other zero-carbon power devices, the engine can realize the use of hydrogen fuel with low purity, and the design of on-line hydrogen production of the engine can improve the integration degree of the engine and the operation safety of the engine.
Detailed Description
The invention is described in more detail below, by way of example, with reference to the accompanying drawings:
Referring to fig. 1-6, fig. 1 is a schematic diagram of the overall structure of the present invention, and an ammonia-hydrogen fuel engine based on a liquid ammonia thermal management supply system includes an ammonia-hydrogen fuel engine 3, a heat recovery unit 6, a cooling unit 8, an exhaust turbocharger 1, exhaust emission ports 4, 5, an intercooler 2, intercooler ports 9, 10, an ammonia supply pump 7, and several pipelines. One path of waste gas and waste heat discharged from the ammonia hydrogen fuel engine system 3 enters the heat recovery unit 6 through the tail gas discharge port 5 via the three-way valve 38, and the other path of waste gas and waste heat enters the heat recovery unit 6 through the tail gas discharge port 4 via the waste gas turbine system. The air is turbocharged by the exhaust gas and then enters the intercooler 2 and then enters the cylinder to improve the air intake efficiency.
Fig. 2 is a schematic diagram of an ammonia-hydrogen fuel engine 3, which comprises an ammonia storage tank 11, an ammonia supply pump 12, a number 1 heat exchanger 13, a sensor 14, an ammonia fuel common rail pipe 15, an ammonia return pipeline 16, an ammonia fuel injector 17, an engine body 18, a cylinder 19, an ammonia return control valve group 31, a gas-liquid separator 23, an electromagnetic three-way valve 22, a buffer tank 24, a self-boosting pump 25 and a mixer 30. The heat exchanger 13 is arranged in the ammonia gas supply unit, so that overheat control of ammonia fuel can be regulated and controlled, a heat source is from waste gas of an ammonia-hydrogen fuel engine system, the ammonia fuel is sprayed into the cylinder 19 for combustion after overheat control, the combustion speed of the ammonia fuel can be accelerated, the combustion efficiency of the ammonia fuel is improved, and meanwhile, the sensor 14 is arranged in an ammonia inlet pipeline to monitor the supplied fuel in real time. For ammonia recovery control of the ammonia fuel, the ammonia fuel is returned to the ammonia storage tank via the gas-liquid separator 23 and the self-boosting pump 25. The hydrogen fuel supply system includes a hydrogen storage tank 26, a pressure reducing valve 27, a buffer tank 28, an electromagnetic three-way valve 29, a hydrogen gas rail 20, and an active prechamber 21. In addition, according to the operation condition of the engine or the external work requirement, the ammonia gas can be controlled to be mixed with the air and the hydrogen entering the cylinder through the ammonia return control valve group 31 and the bypass pipeline and then enter the cylinder for fuel compensation.
Fig. 3 is a schematic diagram of a ammonia recovery control valve group structure of a core component of an ammonia recovery control unit, 31-1, 31-2 and 31-3 are electronic expansion valves with controllable opening degrees, when the 31-1 is opened, the 31-2 and 31-3 are closed, ammonia recovery is collected into an ammonia storage tank 11 through a self-boosting pump, when the 31-1 and the 31-2 are simultaneously opened or the 31-2 is independently opened, the opening degree of the 31-3 is closed, the ammonia quantity entering the mixer 30 can be controlled by adjusting the opening degree of the 31-2, the 31-3 can be used as a safety valve, or the electromagnetic three-way valve 22 is matched, and the regulation function of the valve group can still be realized through the valve 31-1 and the electromagnetic three-way valve 22 when the 31-2 fails.
Fig. 4 is a schematic diagram of the heat recovery unit 6, which includes electromagnetic three-way valves 38, 37, no. 2 heat exchanger 32, no. 3 heat exchanger 39, turbines 33, 34, a thermal cracker 40, an expansion valve 35, and an SCR aftertreatment device 36. Waste heat discharged from the exhaust gas turbocharger 1 is subjected to heat exchange by the No. 2 heat exchanger 32 and then enters the SCR device 36 for discharge. Ammonia entering the heat management system from the ammonia tank is converted into ammonia steam from liquid state after absorbing heat through the heat exchanger 32, and enters the turbine 34 to be expanded and converted into mechanical energy to be output, and the energy grade of ammonia entering the heat recovery unit 6 from the turbine 33 is lower than that of primary waste gas entering from the tail gas port 5, so that ammonia entering the heat recovery unit 6 after absorbing waste gas through the heat exchanger 39 to be overheated becomes gaseous ammonia, and then the gaseous ammonia can enter the thermal cracker 40 to decompose the ammonia into nitrogen and hydrogen through the three-way valve 37, and the hydrogen enters the hydrogen storage tank to be used as a pilot fuel, and can enter the SCR aftertreatment device 36 through the three-way valve. The exhaust gas generated from the cracked gas is converted into shaft work by the turbine 34 coaxial with the turbine 33 and then discharged. Waste heat exiting the exhaust port 5 enters the SCR aftertreatment device 36 via the expansion valve 35 via the heat exchanger 39.
Fig. 5 is a schematic diagram of a cooling system 8, which includes a cooling water unit including a water tank 41, a radiator 42, an intercooler cooling water outlet 43, an engine cooling water outlet 47, a cooling water pump 48, an engine cooling water inlet 49, and an intercooler cooling water inlet 50, and a lubricant cooling unit including a lubricant tank 46, a radiator 44, and a lubricant pump 45.
The turbocharger is connected between an exhaust gas output end of the engine and an exhaust gas input end of the heat recovery unit, and an air output end of the turbocharger is connected with an air inlet channel of the engine through a pipeline.
The fuel supply of the ammonia-hydrogen fuel engine comprises a liquid ammonia supply unit, a hydrogen fuel supply unit, an ammonia return control unit and an in-cylinder direct injection device.
The ammonia storage tank of the liquid ammonia supply unit is connected with an ammonia supply pump, is connected to an ammonia fuel common rail pipe through an overheating heat exchanger and a sensor, and is provided with an electric control three-way valve with adjustable opening between an exhaust gas discharge pipeline and the No.1 heat exchanger and between the exhaust gas discharge pipeline and the No. 3 heat exchanger, so that the overheating degree of liquid ammonia fuel and ammonia gas is regulated, and the overheating control of the liquid ammonia fuel is realized;
The device comprises a liquid ammonia cylinder, a liquid ammonia direct injection device, an ammonia return storage tank, an ammonia supply pump, a reversing valve, a gas-liquid separator, a buffer tank, a self-boosting pump, an ammonia return control valve group, a liquid ammonia cylinder direct injection device, an ammonia return storage tank and an ammonia supply pipeline, wherein the ammonia supply pump is connected with the liquid ammonia cylinder;
the hydrogen fuel supply unit controls the supply of hydrogen fuel, the hydrogen storage tank 26 is connected with the pressure reducing valve 22, the hydrogen gas rail 20 is connected with the active precombustor 21 for igniting hydrogen through the buffer tank 28, the hydrogen fuel or hydrogen gas mixture is ignited by the spark plug in the precombustor, and enters the main combustion chamber through the precombustor spray hole to ignite ammonia fuel.
The engine cooling unit is divided into a cooling water loop and a lubricating oil cooling loop, and comprises a generator cooling water pump 48, radiators 42 and 44, an intercooler, a lubricating oil pump 45, a lubricating oil tank 46 and a cooling water tank 41, wherein the cooling water tank 41 in the cooling water loop is directly connected with the intercooler 2 and the engine 3, the engine 3 and the intercooler are connected with the water pump and are connected with the radiator 42, the lubricating oil tank 46 in the lubricating oil cooling loop is connected with the engine, and the engine is connected with the lubricating oil pump 45 and is connected with the radiator 44.
The post-processor and the cracker form multi-element coupling with the heat recovery unit of the engine, the heat recovery unit comprises a multi-stage heat recovery component, a thermal cracker 40, an SCR post-treatment device 36 and a plurality of heat exchangers, an exhaust pipeline is divided into two parts, one part is connected with a turbocharger and connected with a No. 2 heat exchanger and finally connected with the SCR post-treatment device 36, the heat design involved in the path is that an ammonia storage tank is connected with a No. 2 ammonia supply pump, the ammonia supply pump is connected with the heat exchanger and is connected with the multi-stage heat recovery component, an expansion end is connected with a No. 3 heat exchanger and is respectively connected with an SCR reducing agent supply end and the thermal cracker 40 through three valves, the other exhaust pipeline is directly connected with the three-way valve without the turbocharger, and is respectively connected with the No. 1 heat exchanger for liquid ammonia overheat control and the No. 3 heat exchanger for reheating the ammonia after expansion of the multi-stage heat recovery component and is finally connected with the SCR post-treatment device 36.
Fig. 6 is a control method for the operation of an ammonia-hydrogen fuel engine based on a liquid ammonia thermal management supply system, and for the example proposed by the present invention, the operation process and control method for the whole engine are as follows:
When the engine is started, hydrogen fuel enters a hydrogen pipeline after passing through a pressure reducing valve 27 in a hydrogen storage tank, is stabilized in pressure in a buffer tank 28, and is kept stable for hydrogen supply, and because the engine is started in a cold state and ammonia fuel is difficult to ignite, the hydrogen fuel enters a mixer 30 through an electromagnetic three-way valve 29 and enters an engine combustion chamber through an air inlet channel, so that the combustion supporting effect is achieved. Ammonia fuel is stored in an ammonia storage tank 11 in a high-pressure liquid state, transported to an ammonia supply pipeline by an ammonia supply pump 12, and exhaust gas introduced from an engine exhaust port 5 can be subjected to superheat regulation in a No. 1 heat exchanger 13 before the ammonia fuel enters a cylinder and is monitored by a sensor 14. The hydrogen enters the precombustion chamber 21 and is ignited by the spark plug, and then enters the cylinder to ignite ammonia spray with high ignition point, so that the engine achieves starting ignition.
When the engine is running stably, the hydrogen in the hydrogen storage tank 26 comes from the ammonia cracking reaction, so that the hydrogen storage tank 26 stores only a small amount of hydrogen for starting, and the safety of the engine is ensured. The online hydrogen production energy of ammonia is derived from the waste heat recovery after the stable operation of the engine, a large amount of waste heat is fully utilized through the heat recovery unit 6, wherein one path of engine tail gas waste heat mainly serves the overheat control of the liquid ammonia supply unit and the energy demand of the reducing agent ammonia in the ammonia cracker 40 and the SCR treatment device 36, the temperature requirement of ammonia cracking or reducing effect is met, meanwhile, the engine shaft work compensation is realized through the effect of ammonia, and the ammonia coming out of the No. 2 heat exchanger 32 can convert heat into mechanical energy through the turbine 33. The high temperature exhaust gas discharged from the engine exhaust port 5 preheats the ammonia fuel entering the cylinder through the three-way valve 38 according to working conditions, the working medium from the turbine 33 is in a gas-liquid coexisting state with higher temperature than liquid ammonia, and the primary waste heat of the heat exchanger 39 increases the ammonia to a higher temperature to enter the ammonia cracker 40. The waste gas after heat exchange from the heat exchanger 39 enters the SCR aftertreatment system 36 through the expansion valve 35, and two paths of waste gas recovery are completed. The ammonia cracker 40 cracks ammonia into nitrogen and hydrogen, the hydrogen is stored in the hydrogen storage tank 26, and the nitrogen and cracked exhaust gas are converted into mechanical energy by the turbine 34 and then enter the aftertreatment device. The other mainly serves an exhaust turbine to pressurize air. The high-temperature exhaust gas discharged from the engine exhaust port 4 pressurizes air through the exhaust turbine 1 to increase the cylinder intake air amount, and then enters the cylinder through the intercooler 2 and the heat exchanger 30.
When the engine is running, low-pressure ammonia returning fuel enters the ammonia storage tank 11 through self-pressurization after passing through the valve group 31, meanwhile, the ammonia returning fuel can also enter the mixer 30 through the ammonia returning control valve group 31, the engine is entered through the air inlet channel, the function of the hydrogen fuel supply unit entering the mixer 30 through the electromagnetic three-way valve 29 is matched, a fuel self-compensation mechanism is formed, and the adaptation of the full working condition range can be realized through an ammonia hydrogen fuel variable proportion compensation mode. When the load of the engine is large, the ammonia fuel compensation with larger concentration can be performed through the mechanism, the power performance of the engine is improved, and when the load is small or the engine is started, the hydrogen fuel compensation with larger concentration can be performed. When the engine is running stably, the combustion compensation pipeline can be closed, low-pressure ammonia returns to the gas-liquid separator 23 through the three-way valve 22, ammonia is stored and stabilized before entering the self-booster pump 25 and before entering the buffer tank 24, and then the ammonia is pressurized and converted into liquid ammonia and then returns to the ammonia storage tank 11.
From the above description, the invention adopts the high-efficiency coupling of the ammonia-hydrogen engine body and the heat recovery unit, fully utilizes the waste heat energy of the engine, improves the energy utilization efficiency and completes the carbonization-free emission of the system. The two injection modes taking direct injection in the cylinder as main and air inlet injection as auxiliary are coupled, combustion in the cylinder of the engine is enhanced, and the multi-working-condition adjustable injection mode is realized so as to adapt to various injection requirements of the engine. The problem of inherent properties of high ignition point and low combustion speed of ammonia fuel is solved by overheat adjusting the ammonia hydrogen fuel engine supply system through the heat recovery unit. Waste heat utilization is performed through waste gas turbocharging, waste heat recovery and ammonia energy supplementing preheating are performed, shaft work compensation is realized through turbine output shaft work, energy is provided for thermal cracking of ammonia and tail gas aftertreatment, and engine integration and safety improvement are realized to a certain extent. The thermal efficiency of the engine is greatly improved through the synergistic effect of the ammonia-hydrogen engine system and the heat recovery unit, and the zero carbon emission of the whole power system is realized.