Control equipment and method for air inlet system of ammonia-diesel dual-fuel engine

Abstract

The invention discloses a control device and method for an ammonia-diesel dual-fuel engine air inlet system, and relates to the field of ammonia-diesel engines. The current ammonia injection flow is determined according to the temperature and pressure of ammonia before injection of an ammonia nozzle, the driving pulse width of the ammonia nozzle and the flow characteristic of the ammonia nozzle; controlling an ammonia gas fuel supply system to supply ammonia gas according to the current ammonia gas injection flow; determining the current diesel injection flow according to the diesel injection pressure, the characteristics of the diesel nozzle and the driving pulse width; determining an ammonia-diesel energy substitution ratio according to the current diesel injection flow and the current ammonia injection flow, identifying an engine operation condition, and obtaining a required intake flow according to the engine operation condition and the ammonia-diesel energy substitution ratio; the opening degree of the two electric control throttle valves is controlled according to the difference value, determined by the air inlet flow meter, between the actual air inlet flow and the required air inlet flow, and quantitative air inlet flow control is achieved; the heat efficiency of combustion of the ammonia diesel engine can be improved, and emission of unburned ammonia gas and nitric oxide can be reduced.

Description

Technical Field

[0001] The present application relates to the field of ammonia-diesel engines, and in particular to a control device and method for an air intake system of an ammonia-diesel dual-fuel engine. Background Art

[0002] As a new type of carbon-free fuel, ammonia is gradually becoming a hot topic in sustainable energy research. Its unique physical and chemical properties, such as the fact that it does not produce greenhouse gas carbon dioxide as a combustion product, high hydrogen energy density, and easy storage and transportation, make ammonia have significant advantages in environmental protection and energy efficiency. Therefore, the research and development and application of ammonia-diesel engines are of great significance to promoting the green transformation of energy structure.

[0003] Ammonia as an engine fuel faces problems such as difficulty in ignition, high ignition energy, long combustion duration, slow flame propagation speed, and high emissions of unburned ammonia and nitrogen oxides. These technical difficulties limit the widespread promotion and application of ammonia diesel engines.

[0004] In order to give full play to the advantages of ammonia fuel and solve these challenges, it is urgently necessary to develop a control method, device and electronic equipment for the intake system of an ammonia-diesel engine to enable the intake system of the ammonia-diesel engine to adapt to the combustion process of the ammonia-diesel and optimize the combustion characteristics of the ammonia-diesel engine according to the engine operating conditions, flexibly control the intake flow rate, thereby improving thermal efficiency and reducing exhaust pollutants, and making positive contributions to promoting the widespread application of clean energy and addressing global climate change.

[0005] The current technical solutions mainly focus on the combustion control and intake system design of ammonia diesel engines. The current mainstream intake system solution of ammonia diesel engines uses the energy of the engine exhaust to pressurize the intake air through a turbocharger, increasing the density of the air entering the cylinder, providing the engine with more sufficient oxygen, and thus improving the combustion efficiency of the fuel. At the same time, in order to ensure that the pressurized hot air does not reduce the combustion effect, the system is also equipped with an intercooler to effectively cool the hot air and ensure that the air temperature entering the engine is appropriate. The turbocharger is equipped with a mechanical bleed valve to limit the maximum intake pressure, thereby limiting the maximum intake volume of the engine under each operating condition.

[0006] This intake system has a simple structure and is suitable for single-fuel engines. It performs well on traditional diesel engines, which is related to the combustion characteristics of diesel. However, it is not suitable for ammonia-diesel dual-fuel engines. It is unable to control the intake flow rate according to the different operating conditions of ammonia-diesel engines. The theoretical air-fuel ratio of ammonia and diesel (the mass ratio between air and fuel in the mixture entering the cylinder of the engine, usually expressed in grams of air consumed per gram of fuel burned. During the operation of the engine, the fuel must form an appropriate ratio with the inhaled air to form a combustible mixture. This ratio is the air-fuel ratio) is different. Under different ammonia-diesel energy ratios, the actual intake volume will not match the theoretical optimal intake volume in actual operation, which not only affects the combustion efficiency of the engine, but also leads to an increase in harmful emissions.

[0007] In order to break through this technical bottleneck, future research and development should focus on integrating sensors, actuators and control systems in the intake system, real-time monitoring and regulating the intake flow according to the engine operating conditions and the ammonia-diesel energy ratio, so as to achieve a combustion process suitable for ammonia-diesel dual-fuel engines and reduce exhaust pollutants. Such technological innovation will open up broader prospects for the application of ammonia-diesel engines in the field of sustainable energy.

[0008] The existing intake system of ammonia diesel engine is a purely mechanical structure without electronic control. It includes a supercharger with a mechanical air bleed valve, an intercooler, an intake pipe and other components. The maximum flow of the intake system is controlled by the mechanical air bleed valve of the supercharger. The working principle is mainly to use the balance between the elastic force of the spring and the gas compression force to achieve constant pressure discharge of the gas. The discharge pressure value of the gas is determined by the pre-compression amount of the spring. Therefore, by adjusting the pre-compression amount of the spring, the opening pressure of the air bleed valve can be changed to a certain extent. The opening pressure adjustment of the mechanical air bleed valve usually needs to be performed in the shutdown state, and is achieved by manually adjusting the pre-compression amount of the spring. Therefore, during the operation of the engine, the opening pressure of the mechanical air bleed valve remains unchanged unless manually adjusted. Therefore, this traditional intake system is suitable for single-fuel engines. In ammonia-diesel dual-fuel engines, the physical and chemical properties of ammonia and diesel determine that the intake volumes required for the combustion of the two fuels are different. The traditional intake system cannot regulate the intake flow rate at the same engine speed and output power and different ammonia-diesel energy ratios, and can only limit the maximum intake flow rate. The intake system matching cannot take into account the combustion performance under all working conditions, that is, high combustion thermal efficiency and low harmful gas pollutant emissions, so it is not suitable for the ammonia-diesel dual-fuel combustion mode.

[0009] Therefore, there is an urgent need to provide a control device and method for the air intake system of an ammonia-diesel dual-fuel engine, so as to solve the problem that the air intake system of the ammonia-diesel dual-fuel engine cannot regulate the intake flow rate according to the ammonia-diesel energy ratio, and can accurately regulate the intake flow rate of the ammonia-diesel dual-fuel engine according to changes in the operating conditions of the ammonia-diesel dual-fuel engine, thereby improving the thermal efficiency of the ammonia-diesel engine combustion and reducing the emissions of unburned ammonia and nitrogen oxides. Summary of the invention

[0010] The purpose of the present application is to provide a control device and method for the intake system of an ammonia-diesel dual-fuel engine, which can improve the thermal efficiency of the ammonia-diesel engine combustion and reduce the emission of unburned ammonia and nitrogen oxides.

[0011] To achieve the above objectives, this application provides the following solutions:

[0012] In a first aspect, the present application provides a control device for an air intake system of an ammonia-diesel dual-fuel engine, the control device for an air intake system of an ammonia-diesel dual-fuel engine comprising: an ammonia fuel supply system, a diesel fuel supply system, an air intake system, an engine combustion chamber, an exhaust system, an electronic system and a control system;

[0013] The ammonia fuel supply system is used to obtain the ammonia temperature and pressure before the ammonia nozzle is injected and to supply ammonia to the engine combustion chamber; and send the ammonia temperature and pressure before the ammonia nozzle is injected to the electronic system and control system; the electronic system and control system are used to determine the current ammonia injection flow rate according to the ammonia temperature and pressure before the ammonia nozzle is injected, the driving pulse width of the ammonia nozzle and the flow characteristics of the ammonia nozzle; and control the ammonia fuel supply system to supply ammonia according to the current ammonia injection flow rate;

[0014] The diesel fuel supply system is used to supply diesel to the engine combustion chamber under the control of the electronic system and the control system; the electronic system and the control system are used to determine the current diesel injection flow rate according to the diesel injection pressure, the characteristics of the diesel nozzle and the driving pulse width;

[0015] The intake system comprises: an intake flow meter and two electronically controlled throttle valves; the intake system is used to fully mix fresh air with ammonia and then deliver it to the engine combustion chamber according to the control of the electronic system and the control system; the electronic system and the control system are used to determine the ammonia-diesel energy substitution ratio according to the current diesel injection flow and the current ammonia injection flow, identify the engine operating conditions, and obtain the required intake flow according to the engine operating conditions and the ammonia-diesel energy substitution ratio; and control the opening of the two electronically controlled throttle valves according to the difference between the actual intake flow determined by the intake flow meter and the required intake flow, so as to realize quantitative control of the intake flow;

[0016] The exhaust system is used to utilize the energy of the exhaust gas in the engine combustion chamber to compress the intake air and increase the intake air volume.

[0017] Optionally, the ammonia fuel supply system specifically includes: an ammonia temperature and pressure sensor arranged at the upper rail of the ammonia nozzle and an ammonia tank, an ammonia filter, a shut-off valve, an ammonia pressure regulating tank, an ammonia nozzle upper rail, an ammonia nozzle, an ammonia nozzle lower rail and a mixer connected in sequence;

[0018] The ammonia temperature and pressure sensor is used to detect the ammonia temperature and pressure on the upper rail of the ammonia nozzle; the ammonia temperature and pressure on the upper rail of the ammonia nozzle are the ammonia temperature and pressure before the ammonia nozzle is sprayed.

[0019] Optionally, the diesel fuel supply system specifically includes: a high-pressure oil pump, a diesel common rail pipe and a diesel nozzle which are connected in sequence.

[0020] Optionally, the air intake system further includes: an air filter, a supercharger and an intercooler;

[0021] The air filter is connected to the intercooler through the electronically controlled throttle valve, the intake air flow meter, and the supercharger;

[0022] The intercooler is communicated with another of the electronically controlled throttle valves.

[0023] Optionally, the electronic system and control system include: an ammonia controller, a diesel controller and an engine management system;

[0024] The ammonia controller transmits the current ammonia injection flow to the engine management system; the diesel controller is used to transmit the current diesel injection flow to the engine management system; the engine management system is used to determine the ammonia-diesel energy substitution ratio based on the current diesel injection flow and the current ammonia injection flow, identify the engine operating conditions, and obtain the required intake flow based on the engine operating conditions and the ammonia-diesel energy substitution ratio; and control the opening of the two electronically controlled throttle valves based on the difference between the actual intake flow determined by the intake flow meter and the required intake flow.

[0025] Optionally, the ammonia controller, the diesel controller and the engine management system communicate via a CAN network.

[0026] In a second aspect, the present application provides a control method for an air intake system of an ammonia-diesel dual-fuel engine, which is applied to the control device for the air intake system of an ammonia-diesel dual-fuel engine; the control method for the air intake system of an ammonia-diesel dual-fuel engine comprises:

[0027] Determine the current ammonia injection flow rate according to the ammonia temperature and pressure before the ammonia nozzle is injected, the driving pulse width of the ammonia nozzle and the flow rate characteristics of the ammonia nozzle;

[0028] Determine the current diesel injection flow rate according to the diesel injection pressure, the characteristics of the diesel nozzle and the driving pulse width;

[0029] Determine the ammonia-diesel energy substitution ratio based on the current diesel injection flow and the current ammonia injection flow, and identify the engine operating conditions;

[0030] The required intake air flow rate is obtained according to the engine operating conditions and the ammonia-diesel energy substitution ratio;

[0031] The actual intake air flow rate is determined based on the temperature and pressure of the intake pipe obtained by the intake air flow meter;

[0032] The opening of the two electronically controlled throttle valves is controlled according to the difference between the actual intake air flow and the required intake air flow to achieve quantitative control of the intake air flow.

[0033] Optionally, a temperature and pressure sensor is used to obtain the temperature and pressure of the ammonia gas before the ammonia gas nozzle is injected.

[0034] Optionally, determining the required intake air volume according to the current ammonia injection flow rate, the current diesel injection flow rate and the ammonia-diesel energy distribution mode specifically includes:

[0035] determining the air flow rate required for ammonia combustion according to the current ammonia injection flow rate;

[0036] Determine the air flow required for diesel combustion according to the current diesel injection flow;

[0037] The required air flow rate is weighted by adding the air flow rate required for ammonia combustion and the air flow rate required for diesel combustion to obtain the required air intake.

[0038] Optionally, controlling the openings of the two electronically controlled throttle valves according to the difference between the actual intake flow rate and the required intake flow rate to achieve quantitative control of the intake flow rate specifically includes:

[0039] According to the difference between the actual intake air flow and the required intake air flow, a PID controller is used to control the opening of the two electronically controlled throttle valves;

[0040] According to the opening of the electronically controlled throttle valve, the intake air flow rate is quantitatively controlled.

[0041] According to the specific embodiments provided in this application, this application has the following technical effects:

[0042] The present application provides a control device and method for an intake system of an ammonia-diesel dual-fuel engine, which determines the current ammonia injection flow rate according to the ammonia temperature and pressure before injection of the ammonia nozzle, the driving pulse width of the ammonia nozzle and the flow characteristics of the ammonia nozzle; determines the current diesel injection flow rate according to the diesel injection pressure, the characteristics of the diesel nozzle and the driving pulse width; and then determines the ammonia-diesel energy substitution ratio according to the current diesel injection flow rate and the current ammonia injection flow rate, identifies the engine operating conditions, and obtains the required intake flow rate according to the engine operating conditions and the ammonia-diesel energy substitution ratio; controls the opening of two electronically controlled throttle valves according to the difference between the actual intake flow rate and the required intake flow rate, so as to achieve quantitative control of the intake flow rate; the present application obtains the air flow rate required for diesel combustion in an ammonia-diesel energy distribution mode under different speeds, loads and ammonia-diesel energy ratios, and then realizes precise control of the fresh air flow rate and the fuel flow rate according to the coordinated control of each system, thereby achieving a theoretically optimal air-fuel ratio, improving the thermal efficiency of the ammonia-diesel engine combustion and reducing the emissions of unburned ammonia and nitrogen oxides. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 This is a schematic diagram of the structure of a control device for an air intake system of an ammonia-diesel dual-fuel engine in one embodiment of the present application;

[0045] Figure 2 This is a schematic diagram of the structure of a control method for an intake system of an ammonia-diesel dual-fuel engine in one embodiment of the present application. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0048] In an exemplary embodiment, Figure 1As shown, a control device for an intake system of an ammonia-diesel dual-fuel engine is provided, the device comprising: an ammonia fuel supply system, a diesel fuel supply system, an intake system, an engine combustion chamber, an exhaust system, an electronic system and a control system;

[0049] The ammonia fuel supply system is used to obtain the ammonia temperature and pressure before the ammonia nozzle is injected and to supply ammonia to the engine combustion chamber; and send the ammonia temperature and pressure before the ammonia nozzle is injected to the electronic system and control system; the electronic system and control system are used to determine the current ammonia injection flow rate according to the ammonia temperature and pressure before the ammonia nozzle is injected, the driving pulse width of the ammonia nozzle and the flow characteristics of the ammonia nozzle; and control the ammonia fuel supply system to supply ammonia according to the current ammonia injection flow rate;

[0050] The diesel fuel supply system is used to supply diesel to the engine combustion chamber under the control of the electronic system and the control system; the electronic system and the control system are used to determine the current diesel injection flow rate according to the diesel injection pressure, the characteristics of the diesel nozzle and the driving pulse width;

[0051] The intake system includes: an intake flow meter and two electronically controlled throttle valves; the intake system is used to fully mix fresh air and ammonia and then deliver them to the engine combustion chamber according to the control of the electronic system and the control system; the electronic system and the control system are used to determine the ammonia-diesel energy substitution ratio according to the current diesel injection flow and the current ammonia injection flow, identify the engine operating conditions, and obtain the required intake flow according to the engine operating conditions and the ammonia-diesel energy substitution ratio; and control the opening of the two electronically controlled throttle valves according to the difference between the actual intake flow determined by the intake flow meter and the required intake flow, so as to achieve quantitative control of the intake flow; the engine operating conditions include speed, water temperature, reference torque, ambient temperature, atmospheric pressure and throttle opening.

[0052] The exhaust system is used to utilize the energy of the exhaust gas in the engine combustion chamber to compress the intake air and increase the intake air volume.

[0053] The present application determines the amount of ammonia and diesel entering the engine for combustion, and then calculates the theoretical required intake flow rate that takes into account both high combustion thermal efficiency and low harmful gas pollutant emissions under this operating condition. The intake flow rate is controlled by controlling the opening of the electronically controlled throttle valve in front of the supercharger and the electronically controlled throttle valve behind the intercooler. The temperature and pressure sensor on the intake manifold behind the electronically controlled throttle valve is used to identify the intake temperature and pressure signal entering the engine, calculate the actual intake flow rate entering the engine, and compare it with the theoretical intake flow rate. The two electronically controlled throttle valves work together to ultimately achieve precise control of the intake flow rate based on the actually measured ammonia-diesel energy substitution rate.

[0054] The ammonia fuel supply system specifically comprises: an ammonia temperature and pressure sensor arranged at the upper rail of the ammonia nozzle, and an ammonia tank, an ammonia filter, a shut-off valve, an ammonia pressure-stabilizing tank, an ammonia nozzle upper rail, an ammonia nozzle, an ammonia nozzle lower rail and a mixer which are connected in sequence;

[0055] The ammonia temperature and pressure sensor is used to detect the ammonia temperature and pressure on the upper rail of the ammonia nozzle; the ammonia temperature and pressure on the upper rail of the ammonia nozzle are the ammonia temperature and pressure before the ammonia nozzle is sprayed.

[0056] The outlet of the ammonia tank is connected to the inlet of the ammonia filter, the outlet of the ammonia filter is connected to the inlet of the cut-off valve, the outlet of the cut-off valve is connected to the inlet of the ammonia pressure regulating tank, the outlet of the ammonia pressure regulating tank is connected to the inlet of the ammonia nozzle upper rail, the ammonia nozzle upper rail is connected to the ammonia nozzle lower rail through the ammonia nozzle, the outlet of the ammonia nozzle lower rail is connected to the ammonia inlet on the mixer, and the ammonia temperature and pressure sensor is arranged on the ammonia upper rail. The mixer has three interfaces, ammonia inlet, fresh air inlet, and mixed gas (ammonia mixed with fresh air) outlet.

[0057] The ammonia controller calculates the injection pulse width of the ammonia nozzle according to the ammonia temperature and pressure measured by the ammonia temperature and pressure sensor, the required ammonia flow rate, and the flow characteristics of the nozzle, and adjusts the ammonia supply amount by controlling the pulse width time of the ammonia nozzle;

[0058] Ammonia tanks are containers for storing liquid or high-pressure gaseous ammonia, providing ammonia fuel for the entire supply system. The design of ammonia tanks must meet requirements such as high pressure and corrosion resistance to ensure safe storage of ammonia.

[0059] Ammonia filters are similar to filters in other fuel systems, used to filter impurities in ammonia, such as particulate matter, to protect subsequent components from contamination and damage. This ensures that the ammonia supplied to the engine is pure, improving combustion efficiency and system reliability.

[0060] In an emergency or when the engine is shut down, the shut-off valve can quickly shut off the ammonia supply to prevent ammonia leakage and ensure the safety of personnel and equipment.

[0061] The ammonia pressure stabilizer keeps the ammonia pressure supplied to the engine stable, ensuring that it fluctuates within a set range, thereby improving the combustion efficiency and stability of the engine.

[0062] The ammonia nozzle upper rail and the ammonia nozzle lower rail are part of the ammonia injection component assembly. The ammonia nozzle upper rail is usually connected to the regulator and the air inlet of the ammonia nozzle. An ammonia temperature and pressure sensor is installed on the ammonia nozzle upper rail. The temperature and pressure fluctuations at this position are small, and it can accurately reflect the initial ammonia temperature and pressure at the inlet of the ammonia nozzle. The ammonia nozzle lower rail is connected to the air outlet of the ammonia nozzle. The ammonia nozzle upper rail and the ammonia nozzle lower rail are bolted to fix the ammonia nozzle in the middle to ensure sealing. The internal flow channels of the ammonia nozzle upper rail and the ammonia nozzle lower rail can reduce the flow resistance of ammonia, and at the same time have a certain volume, which plays a role in stabilizing the ammonia pressure.

[0063] The ammonia nozzle sprays ammonia into the engine intake pipe in gaseous form, and is responsible for injecting ammonia from the storage container into the engine intake pipe in a timely and quantitative manner. After mixing with fresh air, it enters the engine to participate in combustion. The design of the nozzle must take into account the physical and chemical properties of ammonia and the working requirements of the engine to ensure that ammonia can be evenly and fully mixed with air to improve combustion efficiency.

[0064] The ammonia temperature and pressure sensor monitors the temperature and pressure of ammonia in real time and transmits these data to the ammonia controller. The ammonia controller adjusts the supply and injection time of ammonia based on these data to optimize the working state and emission performance of the engine. At the same time, the sensor is also an important basis for fault diagnosis and predictive maintenance.

[0065] The mixer is used to premix ammonia and air. Premixing can improve the mixing uniformity of ammonia and air. The design of the mixer needs to consider factors such as mixing ratio and mixing uniformity.

[0066] The various components of the ammonia fuel supply system work together to ensure the safe and efficient supply of ammonia fuel to meet the engine's operating requirements and optimize its performance.

[0067] The ammonia flow rate calculation formula is as follows:

[0068] Where Q is the mass flow rate through the nozzle (unit: kg / s). d is the flow coefficient of the nozzle, usually a number less than 1, indicating the efficiency of the nozzle. A is the outlet area of ​​the nozzle (unit: m 2 ). γ is the specific heat ratio of ammonia. For an ideal gas, this value is usually close to the ratio of the heat capacity at constant pressure to the heat capacity at constant volume. P is the ammonia pressure at the nozzle inlet (unit: Pa). ρ is the density of ammonia at the nozzle inlet temperature (unit: kg / m 3 ). P0 is the ambient pressure at the nozzle outlet (unit: Pa), which can usually be considered as atmospheric pressure.

[0069] The diesel fuel supply system specifically includes: a high-pressure oil pump, a diesel common rail pipe and a diesel nozzle which are connected in sequence.

[0070] The diesel fuel supply system ensures that the diesel can be injected into the engine combustion chamber to ignite the ammonia according to the set time, injection amount, injection pressure, and injection times;

[0071] The high-pressure fuel pump draws diesel from the fuel tank and delivers it to the diesel high-pressure fuel pump through the fuel pipe and filter. Inside the high-pressure fuel pump, the diesel is pressurized to a set pressure (usually up to 1800 bar) to meet the needs of igniting ammonia. According to the working conditions and load changes of the engine, the high-pressure fuel pump can accurately control the fuel supply and stable fuel supply pressure.

[0072] The diesel common rail is an important part that connects the high-pressure fuel pump and each injector. Its main functions include: the common rail accumulates the high-pressure diesel output by the high-pressure fuel pump and distributes the diesel to each injector through stable pressure distribution. Ensure that each injector can obtain high-pressure diesel at the same pressure. The diesel common rail has a certain volume, which can absorb the pressure fluctuations generated during the fuel supply process of the high-pressure fuel pump and the pressure oscillations caused by the injection process of the injector, so that the pressure fluctuations in the high-pressure fuel rail are controlled within a certain range (such as within 5 bar). The diesel pressure in the diesel common rail is set and maintained by the ECU (engine control system) to ensure that the injector can inject according to the predetermined pressure.

[0073] The diesel nozzle is the terminal execution component of the diesel supply system. Its main functions include: under high pressure, the diesel nozzle sprays the diesel into extremely fine mist particles, greatly increasing the contact area between the diesel and the air, and promoting the full combustion of the diesel. The diesel is injected into the engine combustion chamber at a fixed time, fixed quantity and fixed pressure to ignite the ammonia.

[0074] Components such as the diesel high-pressure fuel pump, diesel common rail pipe and diesel nozzle perform their respective functions in the diesel supply system and cooperate with each other to ensure the efficient and stable operation of the diesel engine.

[0075] The diesel flow calculation formula is as follows:

[0076] Q is the diesel flow rate through the nozzle (in cubic meters or liters). Cd is the flow coefficient of the nozzle, which is a dimensionless number that usually needs to be determined experimentally or provided by the nozzle manufacturer. It represents the ratio between the actual flow rate of the nozzle and the theoretical maximum flow rate. A is the effective flow area of ​​the nozzle hole (in square meters or square millimeters). △P is the pressure difference before and after the nozzle, that is, the difference between the common rail pressure and the ambient pressure at the nozzle outlet (in Pascals). ρ is the density of diesel (in kilograms per cubic meter or grams per cubic centimeter). t is the opening time of the nozzle, that is, the power-on time (in seconds). This formula is based on the Bernoulli equation and the fluid continuity equation, which assumes that the fluid is incompressible and the flow in the nozzle is a one-dimensional steady flow. These assumptions are usually reasonable under the working conditions of the diesel nozzle. It should be noted that the driving waveform of the nozzle will affect the opening and closing characteristics of the nozzle, but this is usually not directly reflected in the flow calculation. The drive waveform mainly affects the nozzle response time and injection characteristics (such as the rapidity of injection start and end). These factors may indirectly affect the actual flow rate, but the specific impact usually needs to be determined through experiments.

[0077] The intake system is an important component of the ammonia-diesel dual-fuel engine. It is responsible for fully mixing a certain amount of fresh air with the ammonia supplied by the ammonia supply system, and introducing the mixed gas into the engine combustion chamber to support the combustion process.

[0078] The air intake system also includes: an air filter, a supercharger and an intercooler;

[0079] The air filter is connected to the intercooler through the electronically controlled throttle valve 1, the intake air flow meter, the supercharger;

[0080] The intercooler is communicated with another electronically controlled throttle valve 2 .

[0081] The air filter removes dust, sand and other impurities from the air entering the engine, ensuring that the air entering the cylinder is clean. This helps maintain the engine's cylinders, pistons and piston rings, and extends the service life of the engine.

[0082] The electronically controlled throttle valve 1 controls the amount of air that enters the engine. By adjusting the opening of the valve, the air flow and speed entering the engine can be controlled. The larger the throttle valve opening, the more air intake, the more complete the combustion of oil and gas, and the greater the output power of the engine. The electronically controlled throttle valve is also connected to the engine management system (ECU) through the electronic control system to achieve precise intake control.

[0083] The intake air flow meter measures the temperature and pressure of the air entering the engine, and calculates the air flow through the principle of the Venturi tube, and transmits this information to the ECU. The ECU calculates and controls the opening of the electronically controlled throttle valves 1 and 2 based on this signal to ensure that the engine's intake air flow reaches the set value.

[0084] The supercharger uses the energy of exhaust gas to compress the intake air, increase the intake volume, and send the high-density mixture into the combustion chamber for combustion, thereby increasing the engine's output power and torque.

[0085] The intercooler reduces the temperature of the supercharged air, increases the intake density and charging efficiency, and thus further improves the engine's power performance and fuel economy. The temperature of the supercharged air will rise. If it enters the engine directly without cooling, it will affect the charging efficiency and combustion effect. The intercooler cools the high-temperature air to a temperature close to the ambient temperature through the heat exchange principle before sending it into the engine.

[0086] Electronically controlled throttle valve 2 (dual throttle valve) In a dual throttle system, the second electronically controlled throttle valve may be used to further refine the control of the intake air volume, or to provide additional intake air adjustment functions under certain operating conditions. Its working principle is similar to that of the first electronically controlled throttle valve.

[0087] The quantitative control of the intake air flow is achieved through the coordinated control of two electronically controlled throttle valves. The intake air flow meter identifies the temperature and pressure of the air in the intake pipe and the principle of the Venturi tube to calculate the intake air flow. When the intake air flow is higher than the required value, the electronically controlled throttle valve 1 is first controlled to be gradually closed to throttle the intake air after the air filter and before the supercharger. When the pressure of the intake pipe measured by the intake air flow meter reaches the set warning value, the electronically controlled throttle valve 1 stops to protect the supercharger. At this time, if the intake air flow is still higher than the required value, the electronically controlled throttle valve 2 is controlled to be gradually closed to throttle the intake air before the mixer after the intercooler, thereby finally achieving the control of the intake air flow.

[0088] Before the supercharger and after the intercooler, the two electronically controlled throttle valves are coordinated to control the actual intake flow of the engine and compare it with the theoretical intake flow. The PID electronically controlled throttle valves are used to finally achieve closed-loop control of the intake flow, thereby improving the overall performance of the ammonia-diesel engine and reducing the content of exhaust pollutants.

[0089] The various components of the intake system work together to ensure that the engine obtains a quantitative air supply under different ammonia-diesel energy ratios and different operating conditions to support efficient combustion and excellent engine performance.

[0090] Electronic systems and control systems include: ammonia controller, diesel controller and engine management system;

[0091] The ammonia controller transmits the current ammonia injection flow to the engine management system; the diesel controller is used to transmit the current diesel injection flow to the engine management system; the engine management system is used to determine the ammonia-diesel energy substitution ratio based on the current diesel injection flow and the current ammonia injection flow, identify the engine operating conditions, and obtain the required intake flow based on the engine operating conditions and the ammonia-diesel energy substitution ratio; and control the opening of the two electronically controlled throttle valves based on the difference between the actual intake flow determined by the intake flow meter and the required intake flow.

[0092] The engine management system calculates the energy ratio of ammonia to diesel, and then calculates the optimal theoretical required intake flow rate under the current energy ratio of ammonia to diesel. By controlling the electronically controlled throttle valves 1 and 2, the actual intake flow rate is controlled to reach the optimal theoretical required intake flow rate. By accurately controlling the intake flow rate, it helps to improve the combustion efficiency of the ammonia-diesel dual-fuel engine, thereby improving the combustion performance of the ammonia-diesel engine and reducing pollutant emissions.

[0093] The ammonia controller, diesel controller and engine management system communicate via the CAN network.

[0094] The electronic system and control system in the present application calculate the theoretical required intake flow rate that takes into account both the combustion performance of ammonia and the reduction of exhaust pollutants according to different working conditions of the ammonia-diesel engine, especially for different ammonia-diesel energy ratios; the intake pressure is controlled by the electronically controlled throttle valve 1 arranged behind the air filter and before the supercharger. When the intake pressure before the supercharger is lower than a certain limit, the electronically controlled throttle valve 1 stops working, which can protect the supercharger and prevent large intake negative pressure and oil leakage;

[0095] When the electronically controlled throttle valve 1 cannot reach the target air flow, the electronically controlled throttle valve 2 arranged after the intercooler and before the mixer continues to throttle the intake air. Compared with the single electronically controlled throttle valve, the boost pressure can be reduced to prevent the supercharger from entering the surge area; the electronically controlled throttle valves 1 and 2 in the intake system are used to coordinately regulate the intake pressure to control the intake flow, and the actual intake flow is compared with the calculated theoretical required intake flow to form a closed-loop control; the ammonia fuel supply system in the intake system has a stable ammonia pressure and can accurately calculate the ammonia injection flow through the ammonia temperature and pressure.

[0096] This application has the following effects:

[0097] The use of dual electronically controlled throttle valves can quickly adjust the shape and cross-sectional area of ​​the intake duct according to the real-time working conditions of the engine, thereby controlling the intake flow. At the same time, the coordinated control of the dual electronically controlled throttle valves can protect the supercharger, prevent large intake negative pressure, and prevent oil leakage from the supercharger intermediate body. It can also reduce the boost pressure, prevent supercharger surging, and achieve precise control of the intake flow.

[0098] Ammonia fuel injection control, diesel injection control, and intake control are coordinated to achieve efficient and stable operation of the engine.

[0099] Based on the same inventive concept, the embodiment of the present application also provides a control method for the intake system of an ammonia-diesel dual-fuel engine involved in the above-mentioned control device. The implementation scheme for solving the problem provided by the control method is similar to the implementation scheme recorded in the above-mentioned device, so the specific limitations in one or more control method embodiments for the intake system of an ammonia-diesel dual-fuel engine provided below can refer to the limitations of the control device for the intake system of an ammonia-diesel dual-fuel engine above, and will not be repeated here.

[0100] In an exemplary embodiment, a control method for an intake system of an ammonia-diesel dual-fuel engine is provided, comprising:

[0101] S101, determining the current ammonia injection flow rate according to the ammonia temperature and pressure before the ammonia nozzle is injected, the driving pulse width of the ammonia nozzle, and the flow rate characteristics of the ammonia nozzle; obtaining the ammonia temperature and pressure before the ammonia nozzle is injected using a temperature and pressure sensor;

[0102] S102, determining the current diesel injection flow rate according to the diesel injection pressure, the characteristics of the diesel nozzle and the driving pulse width.

[0103] S103, determining an ammonia-diesel energy substitution ratio according to a current diesel injection flow rate and a current ammonia injection flow rate, and identifying an engine operating condition;

[0104] S103 specifically includes:

[0105] S31, determining the air flow rate required for ammonia combustion according to the current ammonia injection flow rate;

[0106] S32, determining the air flow required for diesel combustion according to the current diesel injection flow;

[0107] S104, obtaining a required intake air flow rate according to the engine operating condition and the ammonia-diesel energy substitution ratio;

[0108] S105, determining the actual intake air flow rate according to the temperature and pressure of the intake pipe obtained by the intake air flow meter;

[0109] S106, controlling the openings of the two electronically controlled throttle valves according to the difference between the actual intake air flow rate and the required intake air flow rate, so as to achieve quantitative control of the intake air flow rate.

[0110] S106 specifically includes:

[0111] According to the difference between the actual intake air flow and the required intake air flow, a PID controller is used to control the opening of the two electronically controlled throttle valves;

[0112] According to the opening of the electronically controlled throttle valve, the intake air flow rate is quantitatively controlled.

[0113] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0114] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A control device for an air intake system of an ammonia-diesel dual-fuel engine, characterized in that: The control device for the air intake system of the ammonia-diesel dual-fuel engine includes: an ammonia fuel supply system, a diesel fuel supply system, an air intake system, an engine combustion chamber, an exhaust system, an electronic system and a control system; The ammonia fuel supply system is used to obtain the ammonia temperature and pressure before the ammonia nozzle is injected and to supply ammonia to the engine combustion chamber; and send the ammonia temperature and pressure before the ammonia nozzle is injected to the electronic system and control system; the electronic system and control system are used to determine the current ammonia injection flow rate according to the ammonia temperature and pressure before the ammonia nozzle is injected, the driving pulse width of the ammonia nozzle and the flow characteristics of the ammonia nozzle; and control the ammonia fuel supply system to supply ammonia according to the current ammonia injection flow rate; The diesel fuel supply system is used to supply diesel to the engine combustion chamber under the control of the electronic system and the control system; the electronic system and the control system are used to determine the current diesel injection flow rate according to the diesel injection pressure, the characteristics of the diesel nozzle and the driving pulse width; The intake system comprises: an intake flow meter and two electronically controlled throttle valves; the intake system is used to fully mix fresh air with ammonia and then deliver it to the engine combustion chamber according to the control of the electronic system and the control system; the electronic system and the control system are used to determine the ammonia-diesel energy substitution ratio according to the current diesel injection flow and the current ammonia injection flow, identify the engine operating conditions, and obtain the required intake flow according to the engine operating conditions and the ammonia-diesel energy substitution ratio; and control the opening of the two electronically controlled throttle valves according to the difference between the actual intake flow determined by the intake flow meter and the required intake flow, so as to realize quantitative control of the intake flow; The exhaust system is used to utilize the energy of the exhaust gas in the engine combustion chamber to compress the intake air and increase the intake air volume.

2. The control device for the air intake system of an ammonia-diesel dual-fuel engine according to claim 1, characterized in that: The ammonia fuel supply system specifically includes: an ammonia temperature and pressure sensor arranged at the upper rail of the ammonia nozzle, and an ammonia tank, an ammonia filter, a shut-off valve, an ammonia pressure-stabilizing tank, an ammonia nozzle upper rail, an ammonia nozzle, an ammonia nozzle lower rail, and a mixer that are sequentially connected; The ammonia temperature and pressure sensor is used to detect the ammonia temperature and pressure on the upper rail of the ammonia nozzle; the ammonia temperature and pressure on the upper rail of the ammonia nozzle are the ammonia temperature and pressure before the ammonia nozzle is sprayed.

3. The control device for the air intake system of an ammonia-diesel dual-fuel engine according to claim 1, characterized in that: The diesel fuel supply system specifically includes: a high-pressure oil pump, a diesel common rail pipe and a diesel nozzle which are connected in sequence.

4. The control device for the air intake system of an ammonia-diesel dual-fuel engine according to claim 1, characterized in that: The air intake system also includes: an air filter, a supercharger and an intercooler; The air filter is connected to the intercooler through the electronically controlled throttle valve, the intake air flow meter, and the supercharger; The intercooler is communicated with another of the electronically controlled throttle valves.

5. The control device for the air intake system of an ammonia-diesel dual-fuel engine according to claim 1, characterized in that: Electronic systems and control systems include: ammonia controller, diesel controller and engine management system; The ammonia controller transmits the current ammonia injection flow to the engine management system; the diesel controller is used to transmit the current diesel injection flow to the engine management system; the engine management system is used to determine the ammonia-diesel energy substitution ratio based on the current diesel injection flow and the current ammonia injection flow, identify the engine operating conditions, and obtain the required intake flow based on the engine operating conditions and the ammonia-diesel energy substitution ratio; and control the opening of the two electronically controlled throttle valves based on the difference between the actual intake flow determined by the intake flow meter and the required intake flow.

6. The control device for the air intake system of an ammonia-diesel dual-fuel engine according to claim 5, characterized in that: The ammonia controller, diesel controller and engine management system communicate via the CAN network.

7. A control method for an air intake system of an ammonia-diesel dual-fuel engine, applied to the control device for an air intake system of an ammonia-diesel dual-fuel engine as claimed in any one of claims 1 to 6, characterized in that: The control method for the air intake system of the ammonia-diesel dual-fuel engine comprises: Determine the current ammonia injection flow rate according to the ammonia temperature and pressure before the ammonia nozzle is injected, the driving pulse width of the ammonia nozzle and the flow rate characteristics of the ammonia nozzle; Determine the current diesel injection flow rate according to the diesel injection pressure, the characteristics of the diesel nozzle and the driving pulse width; Determine the ammonia-diesel energy substitution ratio based on the current diesel injection flow and the current ammonia injection flow, and identify the engine operating conditions; The required intake air flow rate is obtained according to the engine operating conditions and the ammonia-diesel energy substitution ratio; The actual intake air flow rate is determined based on the temperature and pressure of the intake pipe obtained by the intake air flow meter; The opening of the two electronically controlled throttle valves is controlled according to the difference between the actual intake air flow and the required intake air flow to achieve quantitative control of the intake air flow.

8. The control method for the air intake system of an ammonia-diesel dual-fuel engine according to claim 7, characterized in that: The temperature and pressure sensor is used to obtain the ammonia temperature and pressure before the ammonia nozzle is injected.

9. The control method for the air intake system of an ammonia-diesel dual-fuel engine according to claim 7, characterized in that: The step of determining the ammonia-diesel energy substitution ratio according to the current diesel injection flow rate and the current ammonia injection flow rate and identifying the engine operating condition specifically includes: determining the air flow rate required for ammonia combustion according to the current ammonia injection flow rate; The air flow required for diesel combustion is determined based on the current diesel injection flow.

10. The control method for the air intake system of an ammonia-diesel dual-fuel engine according to claim 7, characterized in that: The method of controlling the openings of the two electronically controlled throttle valves according to the difference between the actual intake flow rate and the required intake flow rate to achieve quantitative control of the intake flow rate specifically includes: According to the difference between the actual intake air flow and the required intake air flow, a PID controller is used to control the opening of the two electronically controlled throttle valves; According to the opening of the electronically controlled throttle valve, the intake air flow rate is quantitatively controlled.

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