CN114575996A - Ammonia gas internal combustion engine and control method thereof - Google Patents

Abstract

An ammonia gas internal combustion engine and a control method thereof belong to the field of internal combustion engines, provide a non-carbon emission internal combustion engine device, and adopt the main strategy of using ammonia gas as fuel in consideration of the problem of difficulty in hydrogen storage and transportation. By introducing the exhaust gas generated by the internal combustion engine into the ammonia cracking device, the partial cracking of ammonia is realized, and the hydrogen generated by the ammonia cracking improves the reactivity of the gas in the cylinder, which can realize the stable operation of the internal combustion engine. The hydrogen used is only used for starting the internal combustion engine, and the amount is small, which can avoid the problem of difficulty in carrying hydrogen. The invention selects the fuel supply strategy according to the working conditions, so as to realize the efficient operation of the ammonia gas internal combustion engine. The designed ammonia gas internal combustion engine starts with pure hydrogen, and after starting, pure ammonia is used as the only fuel to supply the internal combustion engine.

Description

A kind of ammonia gas internal combustion engine and control method thereof

technical field

The invention provides an ammonia gas internal combustion engine system and a control method thereof, in particular to the design of an internal combustion engine fuel supply system using ammonia gas as a fuel and a corresponding control method, belonging to the field of internal combustion engines.

Background technique

Energy and the environment are the key issues that people are currently concerned about. The greenhouse effect causes environmental problems such as global warming and sea level rise, and carbon dioxide is the largest contributor to the greenhouse effect. How to reduce carbon emissions is a huge problem currently facing. The automobile industry is one of the main sources of carbon emissions. Traditional vehicles mainly use gasoline and diesel as fuel for combustion, which will cause a lot of carbon emissions. Therefore, the transformation of vehicle energy should be pursued and reasonable alternative fuels should be sought. Gradually move vehicle fuels from traditional hydrocarbon fuels to carbon-free clean fuels.

Although hydrogen is considered to be a clean and reasonable energy carrier, it can be used as fuel combustion and fuel cells, but hydrogen has problems such as storage and transportation difficulties, and the cost and safety greatly reduce the prospect of hydrogen as an energy source. . As an ideal energy storage material, ammonia gas can also be used as a potential alternative energy source. Its molecules do not contain carbon elements, and the complete combustion products only include water and nitrogen. And compared with most gas fuels, it has the characteristics of being easily compressed into a liquid state, making it convenient for storage and transportation. As the second largest chemical product in the world, ammonia related storage and transportation facilities are relatively complete. Therefore, ammonia has the potential to become an alternative fuel for internal combustion engines.

The problem of ammonia as an internal combustion engine fuel is its low reactivity, so it often appears in the field of internal combustion engines in the form of co-firing with hydrogen. However, this again faces the problem that hydrogen is difficult to carry in large quantities on vehicles. However, ammonia cracks at high temperatures, and catalysts facilitate this process. Considering the above problems, the present invention proposes an ammonia gas internal combustion engine and a control method, and specifically relates to a system device design of an internal combustion engine using ammonia gas as a fuel and a control method for the operation of the entire internal combustion engine. In the invention, the exhaust gas waste heat of the ammonia gas internal combustion engine is used as the main heat source, and the exhaust gas generated by the internal combustion engine is passed into the ammonia gas cracking reactor to provide the high temperature environment required for the ammonia gas cracking. Under the action of the catalyst, it is decomposed into hydrogen and nitrogen, and the cracked products and incompletely cracked ammonia can be sent to the cylinder as fuel for combustion. will be more stable. In this study, only a small amount of pure hydrogen is used to assist the starting of the internal combustion engine, almost using ammonia gas as the only fuel, and the stable operation of the ammonia gas internal combustion engine can be achieved.

SUMMARY OF THE INVENTION

In order to improve the carbon emission problem of traditional internal combustion engines, the present application provides an ammonia gas engine that uses ammonia gas as fuel and enhances combustion through ammonia gas cracking.

The specific content of the present invention is the following technical solutions:

An ammonia gas internal combustion engine comprises: an air intake pipeline (P1) is serially connected in sequence: an air filter (1), an intake pressure sensor (2), an intake temperature sensor (3), and an intake flow sensor (4) ; The exhaust pipeline (P2) is connected in series with: an exhaust flow sensor (11), an exhaust temperature sensor (12); the first ammonia supply pipeline (P3) is connected in series with an ammonia tank (13), The first ammonia gas pipeline pressure reducing valve (14), the first ammonia gas volume flow controller (15), the first ammonia gas filter (16); the cracked ammonia gas supply pipeline (P4) is serially connected in sequence: ammonia gas A gas cracking reactor (17), an electric heating device (18), and a cracking ammonia gas nozzle (6); an ammonia gas tank (13) and a second ammonia gas pipeline reducer are sequentially connected in series on the second ammonia gas supply pipeline (P4). Pressure valve (19), second ammonia gas volume flow controller (20), second ammonia gas filter (21), ammonia gas nozzle (7); the hydrogen supply pipeline (P6) is connected in series with: hydrogen gas Tank (25), hydrogen pressure reducing valve (24), hydrogen volume flow controller (23), flame retardant valve (22) and hydrogen nozzle (5); ammonia gas internal combustion engine (8), spark plug (9), rotational speed sensor ( 10), electronic control unit ECU (26);

The electronic control unit ECU (26) is connected with the hydrogen volume flow controller (13) and obtains the hydrogen volume flow signal a;

The electronic control unit ECU (26) is connected with the intake pressure sensor (2) and obtains the intake pressure signal b;

The electronic control unit ECU (26) is connected with the intake air temperature sensor (3) and obtains the intake air temperature signal c;

The electronic control unit ECU (26) is connected with the intake air flow sensor (4) and obtains the intake air flow signal d;

The electronic control unit ECU (26) is connected with the hydrogen nozzle (5) and sends a hydrogen injection signal e to control the opening and closing of the hydrogen nozzle (5);

The electronic control unit ECU (26) is connected with the cracked ammonia gas nozzle (6) and sends a cracked ammonia gas injection signal f to control the opening and closing of the cracked ammonia gas nozzle (6);

The electronic control unit ECU (26) is connected with the ammonia gas nozzle (7) and sends a cracked ammonia gas injection signal g to control the opening and closing of the ammonia gas nozzle (7);

The electronic control unit ECU (26) is connected to the spark plug (9) and sends an ignition signal h to control the spark plug (8) to discharge;

The electronic control unit ECU (26) is connected with the exhaust gas flow sensor (11) and obtains the exhaust gas flow signal i;

The electronic control unit ECU (26) is connected with the exhaust gas temperature sensor (12) and obtains the exhaust gas temperature signal j;

The electronic control unit ECU (26) is connected with the electric heating device (18) and sends a heating signal k to control the electric heating device (16) to release heat;

The electronic control unit ECU (26) is connected with the rotational speed sensor (10) and obtains the rotational speed signal 1 of the internal combustion engine;

The electronic control unit ECU (26) is connected with the first ammonia gas volume flow controller (15) and obtains the first ammonia gas volume flow signal m.

The electronic control unit ECU (26) is connected with the second ammonia gas volume flow controller (20) and obtains a second ammonia gas volume flow signal n.

An internal combustion engine control method using ammonia as fuel includes the following controls:

The electronic control unit ECU (26) receives the signal 1 from the rotational speed sensor (10) and the signal b from the intake pressure sensor (2) to obtain the current rotational speed r (r/min) and the intake pressure P (kPa), respectively.

When r changes from r=0 to r≠0, the internal combustion engine is in the starting stage. At this time, the internal combustion engine is in a cold state. Using pure hydrogen as an auxiliary can make the internal combustion engine start successfully. Therefore, the pure hydrogen mode is adopted at this stage, and the electronic control unit ECU (26) provides hydrogen supply for the ammonia gas internal combustion engine (8) through the signal a to the hydrogen volume flow controller (23); seconds; make the excess air coefficient λ=1.5 during the starting process;

Always keep the excess air coefficient λ=1 after starting;

When 0<r≤3000r/min, P≤70kPa, it is a low load state at this time, the pyrolysis ammonia mode can meet the power demand of the internal combustion engine, and the electronic control unit ECU (26) outputs the signal m to the first ammonia gas volume flow control The device (15) provides ammonia gas for the ammonia gas cracking reactor (17), and after the ammonia gas is cracked, it provides fuel for the ammonia gas internal combustion engine.

When 0<r≤3000r/min, P>70kPa, it is a high load state. In order to ensure sufficient power, the joint supply mode of cracked ammonia gas and ammonia gas is adopted. The electronic control unit ECU (26) outputs the signal m to the first An ammonia gas volume flow controller (15) outputs a signal n to a second ammonia gas volume flow controller (20), so that the internal combustion engine obtains cracked ammonia gas and ammonia gas supply. The ratio of the second ammonia supply pipeline to the total ammonia flow is Q=0.2*r/3000+0.3*P/100.

When r>3000r/min, in order to ensure the power, the co-supply mode of cracked ammonia gas and ammonia gas is adopted, and the electronic control unit ECU (26) outputs the signal m to the first ammonia gas volume flow controller (15) and the output signal n respectively. to the second ammonia gas volume flow controller (20), so that the internal combustion engine obtains cracked ammonia gas and ammonia gas supply. The ratio of the flow rate of the second ammonia gas supply pipeline to the total ammonia gas flow rate is Q=0.2*r/3000+0.3*P/100.

The electronic control unit ECU (26) calculates the exhaust gas waste heat energy through the exhaust gas temperature signal j and the exhaust gas flow signal i; when the exhaust gas waste heat energy is insufficient, the electronic control unit (ECU) calculates the exhaust gas waste heat energy according to the energy required for cracking ammonia gas and the exhaust gas waste heat energy The energy obtains the supplementary heat required by the electric heating device (18); the electronic control unit ECU (26) sends a heating signal k to control the operation of the electric heating device (18).

The electronic control unit ECU (26) outputs signal e, signal f, and signal g to control hydrogen gas, cracked ammonia gas, and ammonia gas to provide fuel supply for the internal combustion engine, and the in-cylinder mixture outputs the ignition signal h through the electronic control unit ECU (26) to control the spark plug. (8) Ignite.

λ=m _air /(m _ammonia *AF _st,ammonia +m _hydrogen *AF _st,hydrogen ), where m _air is the air mass flow, and the electronic control unit ECU (26) receives the intake air pressure signal b and the intake air temperature signal c Calculate the air mass flow with the intake air flow signal d, m _ammonia and m _hydrogen are the ammonia mass flow and hydrogen mass flow respectively, AF _st,ammonia and AF _st,hydrogen are the air-fuel ratio of ammonia and hydrogen respectively; m _Ammonia is 0. After the start, m _hydrogen is 0, and m _ammonia is the total ammonia gas mass flow calculated by the ECU according to the first ammonia gas volume flow signal and the second ammonia gas volume flow signal.

The main advantages of the present invention are: a non-carbon emission internal combustion engine device is provided. And taking into account the difficulty of hydrogen storage and transportation, the main strategy of ammonia as fuel is adopted. By introducing the exhaust gas generated by the internal combustion engine into the ammonia cracking device, the partial cracking of ammonia is realized, and the hydrogen generated by the ammonia cracking improves the reactivity of the gas in the cylinder, which can realize the stable operation of the internal combustion engine. The hydrogen used in the invention is only used for starting the internal combustion engine, and the amount is small, which can avoid the problem of difficulty in carrying hydrogen.

Description of drawings

Fig. 1 Schematic diagram of an ammonia internal combustion engine system

In the figure: Air intake line (P1), air filter (1), intake pressure sensor (2), intake temperature sensor (3), intake flow sensor (4), exhaust line (P2) , exhaust flow sensor (11), exhaust temperature sensor (12), ammonia gas supply pipeline (P3), ammonia gas tank (13), first ammonia gas pipeline pressure reducing valve (14), first ammonia gas volume Flow controller (15), first ammonia filter (16), pyrolysis ammonia supply pipeline (P4), ammonia pyrolysis reactor (17), electric heating device (18), pyrolysis ammonia nozzle (6) ), the second ammonia gas supply pipeline (P4), the second ammonia gas pipeline pressure reducing valve (19), the second ammonia gas volume flow controller (20), the second ammonia gas filter (21), the ammonia gas Nozzle (7); hydrogen supply pipeline (P6), hydrogen tank (25), hydrogen pressure reducing valve (24), hydrogen volume flow controller (23), flame retardant valve (22), hydrogen nozzle (5), internal combustion engine (8), spark plug (9), rotational speed sensor (10), electronic control unit ECU (21);

Hydrogen volume flow signal a, intake pressure signal b, intake temperature signal c, intake flow signal d, hydrogen injection signal e, pyrolysis ammonia injection signal f, ammonia injection signal g, ignition signal h, exhaust flow signal i, exhaust temperature signal j, heating signal k, internal combustion engine speed signal l, first ammonia gas volume flow signal m, second ammonia gas volume flow signal n.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

An ammonia gas internal combustion engine comprises: an air intake pipeline (P1) is serially connected in sequence: an air filter (1), an intake pressure sensor (2), an intake temperature sensor (3), and an intake flow sensor (4) ; The exhaust pipeline (P2) is connected in series with: an exhaust flow sensor (11), an exhaust temperature sensor (12); the first ammonia supply pipeline (P3) is connected in series with an ammonia tank (13), The first ammonia gas pipeline pressure reducing valve (14), the first ammonia gas volume flow controller (15), the first ammonia gas filter (16); the cracked ammonia gas supply pipeline (P4) is serially connected in sequence: ammonia gas A gas cracking reactor (17), an electric heating device (18), and a cracking ammonia gas nozzle (6); an ammonia gas tank (13) and a second ammonia gas pipeline reducer are sequentially connected in series on the second ammonia gas supply pipeline (P4). Pressure valve (19), second ammonia gas volume flow controller (20), second ammonia gas filter (21), ammonia gas nozzle (7); the hydrogen supply pipeline (P6) is connected in series with: hydrogen gas Tank (25), hydrogen pressure reducing valve (24), hydrogen volume flow controller (23), flame retardant valve (22) and hydrogen nozzle (5); ammonia gas internal combustion engine (8), spark plug (9), rotational speed sensor ( 10), electronic control unit ECU (26);

The electronic control unit ECU (21) receives the intake pressure signal b, the intake temperature signal c, the intake flow signal d, the exhaust flow signal i, and the exhaust temperature signal j; sends out the hydrogen volume flow signal a and the hydrogen injection signal e, cracked ammonia injection signal f, ammonia injection signal g, ignition signal h, heating signal k, first ammonia volume flow signal m, second ammonia volume flow signal n.

The electronic control unit ECU (26) receives the signal 1 from the rotational speed sensor (10) and the signal b from the intake pressure sensor (2) to obtain the current rotational speed r (r/min) and the intake pressure P (kPa), respectively.

When r changes from r=0 to r≠0, the internal combustion engine is in the starting stage, and the pure hydrogen mode is adopted at this time. ) supply hydrogen; set the starting time to be 3 seconds; make the excess air coefficient λ=1.5 during the starting process;

Always keep the excess air coefficient λ=1 after starting;

When 0<r≤3000r/min, P≤70kPa, the ammonia cracking mode is adopted, and the electronic control unit ECU (26) outputs the signal m to the first ammonia volume flow controller (15) as the ammonia cracking reactor (17) Ammonia gas is provided, and after the ammonia gas is cracked, it provides fuel for the ammonia gas internal combustion engine.

When 0<r≤3000r/min, P>70kPa, the mode of co-supplying cracked ammonia gas and ammonia gas is adopted, and the electronic control unit ECU (26) outputs the signal m to the first ammonia gas volume flow controller (15) and the output signal respectively. n to the second ammonia gas volume flow controller (20), so that the internal combustion engine obtains cracked ammonia gas and ammonia gas supply. The ratio of the second ammonia supply pipeline to the total ammonia flow is Q=0.2*r/3000+0.3*P/100.

When r>3000r/min, the mode of co-supplying cracked ammonia gas and ammonia gas is adopted, and the electronic control unit ECU (26) respectively outputs the signal m to the first ammonia gas volume flow controller (15) and the output signal n to the second ammonia gas The volume flow controller (20) enables the internal combustion engine to obtain cracked ammonia gas and ammonia gas supply. The ratio of the second ammonia supply pipeline to the total ammonia flow is Q=0.2*r/3000+0.3*P/100.

The electronic control unit ECU (26) calculates the exhaust gas waste heat energy through the exhaust gas temperature signal j and the exhaust gas flow signal i; when the exhaust gas waste heat energy is insufficient, the electronic control unit (ECU) calculates the exhaust gas waste heat energy according to the energy required for cracking ammonia gas and the exhaust gas waste heat energy The energy obtains the supplementary heat required by the electric heating device (18); the electronic control unit ECU (26) sends a heating signal k to control the operation of the electric heating device (18);

The electronic control unit ECU (26) outputs signal e, signal f, and signal g to control hydrogen gas, cracked ammonia gas, and ammonia gas to provide fuel supply for the internal combustion engine, and the in-cylinder mixture outputs the ignition signal h through the electronic control unit ECU (26) to control the spark plug. (8) Ignite.

λ=m _air /(m _ammonia *AF _st,ammonia +m _hydrogen *AF _st,hydrogen ), where m _air is the air mass flow, and the electronic control unit ECU (26) receives the intake air pressure signal b and the intake air temperature signal c Calculate the air mass flow with the intake air flow signal d, m _ammonia and m _hydrogen are the ammonia mass flow and hydrogen mass flow respectively, AF _st,ammonia and AF _st,hydrogen are the air-fuel ratio of ammonia and hydrogen respectively; m _Ammonia is 0. After the start, m _hydrogen is 0, and m _ammonia is the total ammonia gas mass flow calculated by the ECU according to the first ammonia gas volume flow signal and the second ammonia gas volume flow signal.

Claims (2)

1. An ammonia internal combustion engine and a control method therefor, characterized by comprising: the air inlet pipeline (P1) is connected in series with: the air purifier comprises an air filter (1), an intake pressure sensor (2), an intake temperature sensor (3) and an intake flow sensor (4); the exhaust pipeline (P2) is connected in series with: an exhaust gas flow rate sensor (11) and an exhaust gas temperature sensor (12); an ammonia tank (13), a first ammonia pipeline pressure reducing valve (14), a first ammonia volume flow controller (15) and a first ammonia filter (16) are sequentially connected in series on the first ammonia supply pipeline (P3); the cracked ammonia gas supply line (P4) is connected in series with: an ammonia cracking reactor (17), an electric heating device (18) and a cracked ammonia nozzle (6); an ammonia tank (13), a second ammonia pipeline pressure reducing valve (19), a second ammonia volume flow controller (20), a second ammonia filter (21) and an ammonia nozzle (7) are sequentially connected in series on the second ammonia supply pipeline (P4); the hydrogen gas supply line (P6) is connected in series with: a hydrogen tank (25), a hydrogen pressure reducing valve (24), a hydrogen volume flow controller (23), a flame retardant valve (22) and a hydrogen nozzle (5); the device comprises an ammonia gas internal combustion engine (8), a spark plug (9), a rotating speed sensor (10) and an electronic control unit ECU (26);

the electronic control unit ECU (26) is connected with the hydrogen volume flow controller (13) and obtains a hydrogen volume flow signal a;

the electronic control unit ECU (26) is connected with the air inlet pressure sensor (2) and obtains an air inlet pressure signal b;

the electronic control unit ECU (26) is connected with the air inlet temperature sensor (3) and obtains an air inlet temperature signal c;

the electronic control unit ECU (26) is connected with the air intake flow sensor (4) and obtains an air intake flow signal d;

the electronic control unit ECU (26) is connected with the hydrogen nozzle (5) and sends a hydrogen injection signal e to control the opening and closing of the hydrogen nozzle (5);

the electronic control unit ECU (26) is connected with the cracked ammonia nozzle (6) and sends out a cracked ammonia injection signal f to control the opening and closing of the cracked ammonia nozzle (6);

the electronic control unit ECU (26) is connected with the ammonia nozzle (7) and sends out a cracked ammonia injection signal g to control the opening and closing of the ammonia nozzle (7);

the electronic control unit ECU (26) is connected with the spark plug (9) and sends an ignition signal h to control the spark plug (8) to discharge;

the electronic control unit ECU (26) is connected with an exhaust flow sensor (11) and obtains an exhaust flow signal i;

the electronic control unit ECU (26) is connected with an exhaust temperature sensor (12) and obtains an exhaust temperature signal j;

the electronic control unit ECU (26) is connected with the electric heating device (18) and sends a heating signal k to control the electric heating device (16) to release heat;

the electronic control unit ECU (26) is connected with the rotating speed sensor (10) and obtains an internal combustion engine rotating speed signal l;

the electronic control unit ECU (26) is connected with the first ammonia volume flow controller (15) and obtains an ammonia volume flow signal m;

the electronic control unit ECU (26) is connected with the second ammonia gas volume and flow controller (20) and obtains an ammonia gas volume and flow signal n.

2. A method of controlling an ammonia internal combustion engine as defined in claim 1, wherein:

an electronic control unit ECU (26) receives a signal l from a rotating speed sensor (10) and a signal b from an air inlet pressure sensor (2) to respectively obtain the current rotating speed r (r/min) and the air inlet pressure P (kPa);

when r is changed from r to 0 to r to 0, the internal combustion engine is in a starting stage, a pure hydrogen mode is adopted at the moment, and an electronic control unit ECU (26) supplies hydrogen to an ammonia internal combustion engine (8) through a signal a to a hydrogen volume flow controller (23); setting the starting time to be 3 seconds constantly; setting the excess air factor lambda to 1.5 during the starting process;

after the start is finished, the excess air coefficient lambda is always kept to be 1;

when r is more than 0 and less than or equal to 3000r/min and P is less than or equal to 70kPa, an ammonia cracking mode is adopted, an electronic control unit ECU (26) outputs a signal m to a first ammonia volume flow controller (15) to provide ammonia for an ammonia cracking reactor (17), and the ammonia is cracked and then provides fuel for an ammonia internal combustion engine;

when r is more than 0 and less than or equal to 3000r/min and P is more than 70kPa, a cracked ammonia gas and ammonia gas common supply mode is adopted, and an electronic control unit ECU (26) respectively outputs a signal m to a first ammonia gas volume flow controller (15) and a signal n to a second ammonia gas volume flow controller (20) so that the internal combustion engine obtains cracked ammonia gas and ammonia gas supply; wherein the second ammonia supply pipeline accounts for the total ammonia flow rate ratio of Q ═ 0.2 r/3000+ 0.3P/100;

when r is more than 3000r/min, a cracked ammonia and ammonia gas common supply mode is adopted, and the electronic control unit ECU (26) respectively outputs a signal m to the first ammonia gas volume flow controller (15) and a signal n to the second ammonia gas volume flow controller (20) so that the internal combustion engine obtains cracked ammonia gas and ammonia gas supply; wherein the second ammonia supply pipeline accounts for the total ammonia flow rate ratio of Q ═ 0.2 r/3000+ 0.3P/100;

an electronic control unit ECU (26) calculates exhaust waste heat energy through an exhaust temperature signal j and an exhaust flow signal i; when the exhaust residual heat energy is insufficient, the Electric Control Unit (ECU) obtains the supplementary heat required by the electric heating device (18) according to the energy required by cracking the ammonia gas and the exhaust residual heat energy; an electronic control unit ECU (26) sends a heating signal k to control the electric heating device (18) to work;

the electronic control unit ECU (26) outputs a signal e, a signal f and a signal g to respectively control hydrogen, cracked ammonia and ammonia to provide fuel for the internal combustion engine, and the mixed gas in the cylinder outputs an ignition signal h to control the ignition of the spark plug (8) through the electronic control unit ECU (26);

λ＝m_air/(m_ammonia*AF_st,ammonia+m_hydrogen*AF_st,hydrogen) Wherein m is_airFor the air mass flow, an electronic control unit ECU (26) receives an air inlet pressure signal b, an air inlet temperature signal c and an air inlet flow signal d to calculate the air mass flow, m_ammoniaAnd m_hydrogenRespectively ammonia mass flow and hydrogen mass flow, AF_st,ammoniaAnd AF_st,hydrogenAir-fuel ratios of ammonia and hydrogen, respectively; in the starting phase m_ammoniaIs 0; m after starting_hydrogenIs 0, m_ammoniaAnd the total ammonia mass flow is calculated by the ECU according to the first ammonia volume flow signal and the second ammonia volume flow signal.

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