Hydrogen fuel engine system and transient control method thereof, vehicle-mounted system

Abstract

The application discloses a hydrogen fuel engine system and a transient control method and a vehicle-mounted system thereof. An air inlet pipeline of the hydrogen fuel engine system is connected with an air inlet manifold of an engine. In the air inlet direction, an air filter, a first supercharger, an intercooler and a throttle valve are sequentially arranged on the air inlet pipeline. A gas injection device is arranged on the air inlet manifold, and a hydrogen nozzle of the gas injection device extends into the air inlet manifold. A cylinder direct injection module of the gas injection device is arranged on the engine, and a hydrogen nozzle of the cylinder direct injection module extends into a cylinder combustion chamber of the engine. An ignition port is arranged on the cylinder combustion chamber and used for igniting the cylinder combustion chamber. An exhaust pipeline is connected with an exhaust manifold of the engine. In the exhaust direction, a second supercharger, a lambda sensor and an oxidation type catalytic converter are sequentially arranged on the exhaust pipeline. The problems of long transient response time caused by low exhaust temperature and poor supercharging capacity of the hydrogen fuel engine can be solved.

Description

Technical Field

[0001] This invention relates to the field of hydrogen fuel cell engine technology, and in particular to a hydrogen fuel cell engine system and its transient control method, as well as an on-board system. Background Technology

[0002] Currently, in the face of environmental and energy conservation, the industry is becoming increasingly stringent in its emission and fuel consumption regulations. Hydrogen, as a carbon-free clean energy source, produces only water when burned, which can essentially achieve zero emissions of carbon and pollutants. Therefore, the use of hydrogen fuel engines can promote the carbon neutrality process.

[0003] Current hydrogen fuel cell engines primarily employ a lean-burn strategy, which offers advantages such as high thermal efficiency and low NOx emissions. However, because lean-burn requires more than twice the intake air volume of stoichiometric combustion, the amount of working fluid in the engine cylinder is higher, resulting in lower combustion temperatures and lower exhaust energy, which is detrimental to driving the turbine. Furthermore, the difficulty in establishing intake pressure in the engine cylinders leads to poor lean-burn performance and weak power for steady-state operation; and poor transient performance due to lower exhaust temperatures result in poor turbocharger transient performance, causing a longer time to achieve the desired power output and resulting in poor acceleration.

[0004] Currently, hydrogen fuel cell engines are still in the research stage both domestically and internationally. There is no industry consensus on the industrial application of hydrogen fuel cell engines for passenger vehicles, and their steady-state and transient control is largely undeveloped. Existing hydrogen fuel cell engine designs typically reference passenger vehicle engine development experience, achieving steady-state performance targets through performance and structural design, while transient response is improved through a two-stage boosting system combining electric motors and turbochargers. However, relying on passenger vehicle engine development experience, improving transient response through two-stage boosting leads to complex structural layouts, control systems, and increased component costs for the electric turbocharger. In the context of electrification, future hydrogen fuel cell engines will mostly be used in hybrid-specific powertrains for new energy vehicles. Therefore, adopting a two-stage electric boosting solution would present challenges such as difficult engine compartment layout and high costs.

[0005] Therefore, optimizing the response performance of hydrogen fuel cell engines while ensuring that combustion stability, NOx emissions, and knock performance are all within reasonable ranges is a technical problem that urgently needs to be solved for the promotion of hydrogen fuel cell engines. Summary of the Invention

[0006] This invention provides a hydrogen fuel cell engine system and its transient control method, as well as an on-board system, which can solve the problem of long transient response time caused by low exhaust temperature and poor boosting capacity in hydrogen fuel cell engines.

[0007] In a first aspect, this application provides a hydrogen fuel cell engine system, comprising:

[0008] An intake pipe is connected to the engine's intake manifold; along the intake direction, an air filter, a first turbocharger, an intercooler, and a throttle valve are sequentially arranged on the intake pipe.

[0009] A gas injection device, comprising a port injection module or a direct injection module, wherein the port injection module is disposed on the intake manifold and the hydrogen nozzle of the port injection module extends into the intake manifold; and the direct injection module is disposed on the engine and the hydrogen nozzle of the direct injection module extends into the cylinder combustion chamber of the engine.

[0010] Spark plug, wherein the spark plug is disposed at the ignition port of the cylinder combustion chamber for igniting the cylinder combustion chamber;

[0011] The exhaust pipe is connected to the exhaust manifold of the engine. Along the exhaust direction, a second turbocharger, a laser sensor, and an oxidation catalytic converter are sequentially installed on the exhaust pipe.

[0012] Optionally, along the exhaust direction, after the oxidative catalytic converter, a selective catalytic reduction device is also provided on the exhaust pipe.

[0013] Optionally, along the exhaust direction, after the oxidizing catalytic converter, a NOx capture device is also provided on the exhaust pipe.

[0014] Optionally, the hydrogen fuel cell engine system also includes a controller;

[0015] The exhaust pipe is also equipped with a selective catalytic reduction device, and the controller is connected to the air filter, the first turbocharger, the intercooler, the throttle body, the port injection module, the spark plug, the second turbocharger, the λ sensor, the oxidative catalytic converter, and the selective catalytic reduction device, respectively; or, the exhaust pipe is also equipped with a NOx capture device, and the controller is connected to the air filter, the first turbocharger, the intercooler, the throttle body, the direct injection module, the spark plug, the second turbocharger, the λ sensor, the oxidative catalytic converter, and the NOx capture device, respectively.

[0016] Secondly, embodiments of this application also provide a transient control method for a hydrogen fuel cell engine system, the transient control method comprising:

[0017] Obtain the initial torque and target torque of the vehicle system at the current moment;

[0018] Compare the target torque with the initial torque;

[0019] When the target torque is greater than the initial torque, the first turbocharger is controlled to increase the hydrogen fuel concentration in the engine, and the spark plug is controlled to ignite at the first ignition angle.

[0020] Real-time acquisition of the excess air coefficient in the exhaust pipe;

[0021] When the excess air coefficient is less than or equal to the knock boundary value corresponding to the target torque, the first turbocharger is controlled to continue to increase the hydrogen fuel concentration in the engine cylinder, while the spark plug is controlled to ignite at the second ignition angle, so that the vehicle system increases from the initial torque to the target torque.

[0022] Wherein, the first ignition angle is smaller than the steady-state ignition angle corresponding to the target torque, and the steady-state ignition angle corresponding to the target torque is smaller than the second ignition angle.

[0023] Optionally, the hydrogen fuel cell engine system includes a gas injection device, which includes a direct injection module. One working cycle of the engine includes an intake stroke, a compression stroke, a power stroke, and an exhaust stroke. During the in-cylinder warming and acceleration phase, the transient control method further includes:

[0024] Before the power stroke ends and the exhaust stroke begins in each working cycle of the engine, the direct injection module is controlled to inject hydrogen fuel into the cylinder combustion chamber, while the spark plug is controlled to ignite.

[0025] The in-cylinder temperature rise acceleration stage refers to the duration during which the torque of the vehicle system increases to the target torque after the spark plug is ignited at the second ignition angle.

[0026] Optionally, during the in-cylinder heating acceleration phase, the engine includes multiple sequentially performed working cycles;

[0027] Controlling the first turbocharger to continue increasing the hydrogen fuel concentration in the engine cylinders, while simultaneously controlling the spark plug to ignite at the second ignition angle, also includes:

[0028] Simultaneously, the second ignition angle of the spark plug is gradually reduced to the steady-state ignition angle corresponding to the target torque during multiple sequential working cycles.

[0029] Optionally, after the on-board system increases from the initial torque to the target torque, the transient control method further includes:

[0030] The spark plug is controlled to ignite at the steady-state ignition angle corresponding to the target torque.

[0031] Optionally, after controlling the first turbocharger to increase the hydrogen fuel concentration in the engine cylinder and simultaneously controlling the spark plug to ignite at the second ignition angle, the transient control method further includes:

[0032] Continue to acquire the excess air coefficient λ in the exhaust pipe in real time;

[0033] The boost ratio of the first booster and the second booster is controlled to stabilize the excess air coefficient λ at the knock boundary value corresponding to the target torque.

[0034] Thirdly, embodiments of this application also provide an on-board system, including the hydrogen fuel cell engine system described in the first aspect.

[0035] In summary, the hydrogen fuel cell engine system provided in this application adopts a transient control method for hydrogen fuel cell engine systems. By controlling ignition timing, system pressurization, and hydrogen injection, it improves transient response performance and reduces acceleration response time. At the same time, it can also avoid problems such as high NOx emissions, poor combustion stability, and abnormal combustion due to the large variation range of the excess air coefficient λ in hydrogen lean combustion. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a hydrogen fuel cell engine system provided in this application;

[0037] Figure 2 This is a schematic diagram of another hydrogen fuel cell engine system provided in this application;

[0038] Figure 3 This is a schematic diagram showing the relationship between NOx and the excess air coefficient λ in a hydrogen fuel cell engine.

[0039] Figure 4 This is a schematic diagram of a transient control method for a hydrogen fuel cell engine system provided in this application;

[0040] Figure 5 This is the correspondence between the ignition angle and the excess air coefficient λ of the hydrogen fuel cell engine system of this application;

[0041] Figure 6 This is a comparison diagram of the transient response time of engine torque between existing technologies and the technology provided in this application;

[0042] Figure 7 This is a schematic diagram of another transient control method for a hydrogen fuel cell engine system provided in this application;

[0043] Figure 8 This is the correspondence between the ignition angle and the excess air coefficient λ of the hydrogen fuel cell engine system of this application;

[0044] Figure 9 This is a comparison diagram of the transient response time of engine torque between existing technologies and the technology provided in this application;

[0045] Figure 10This is a schematic diagram of the late injection strategy during the working cycle of the engine provided in this application;

[0046] Figure 11 This is a logic control diagram of a hydrogen fuel cell engine system provided in this application;

[0047] Figure 12 This is a logic control diagram of a hydrogen fuel cell engine system provided in this application.

[0048] The accompanying diagram is described as follows:

[0049] 20-Intake pipe, 21-Air filter, 22-Turbocharger, 23-Intercooler, 24-Throttle body, 11-Intake manifold, 41-Port injection module, 42-Direct injection module, 13-Spark plug, 14-Exhaust manifold, 30-Exhaust pipe, 32-λ sensor, 33-Oxidation catalytic converter, 34-Selective catalytic reduction device, 35-NOx capture device. Detailed Implementation

[0050] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0051] The present invention provides a hydrogen fuel cell engine system in view of one or more of the above-mentioned problems existing in the prior art. Figure 1 This is a schematic diagram of the structure of a hydrogen fuel cell engine system provided in this application;

[0052] Figure 2 This is a schematic diagram of another hydrogen fuel cell engine system provided in this application; Figure 3 This is a schematic diagram showing the relationship between NOx and the excess air coefficient λ in a hydrogen fuel cell engine. (Combined with...) Figure 1As shown in the figure, a hydrogen fuel cell engine system provided in this application includes an engine 10, an intake pipe 20, an exhaust pipe 30, and a gas injection device 40. The intake pipe 20 is connected to the intake manifold 11 of the engine 10. Along the intake direction (as indicated by arrow L1 in the figure), an air filter 21, a first turbocharger 22, an intercooler 23, and a throttle valve 24 are sequentially arranged on the intake pipe 20. The gas injection device 40 includes a gas port injection module 41, which is arranged on the intake manifold 11, and the hydrogen nozzle of the gas port injection module 41 extends into the intake manifold 11. A spark plug 13 is arranged at the ignition port of the cylinder combustion chamber 12 for igniting the cylinder combustion chamber 12. The exhaust pipe 30 is connected to the exhaust manifold 14 of the engine 10. Along the exhaust direction (as indicated by arrow L2 in the figure), a second turbocharger 31, a λ sensor 32, and an oxidation catalytic converter 33 are sequentially arranged on the exhaust pipe 30.

[0053] Combination Figure 2 As shown, an embodiment of this application provides a hydrogen fuel cell engine system including an engine 10, an intake pipe 20, an exhaust pipe 30, and a gas injection device 40. The intake pipe 20 is connected to the intake manifold 11 of the engine 10. Along the intake direction L1, an air filter 21, a first turbocharger 22, an intercooler 23, and a throttle valve 24 are sequentially arranged on the intake pipe 20. The gas injection device 40 includes a direct injection module 42, which is mounted on the engine 10. The hydrogen nozzle of the direct injection module 42 extends into the cylinder combustion chamber 12 of the engine 10. A spark plug 13 is mounted at the ignition port of the cylinder combustion chamber 12 for igniting the cylinder combustion chamber 12. The exhaust pipe 30 is connected to the exhaust manifold 14 of the engine 10. Along the exhaust direction L2, a second turbocharger 31, a λ sensor 32, and an oxidation catalytic converter 33 are sequentially arranged on the exhaust pipe 30.

[0054] For example, in combination Figure 1 and Figure 2 As shown, the engine 10 of the hydrogen fuel cell engine system is a hydrogen internal combustion engine (HICE), also called a hydrogen fuel cell engine. Based on a traditional internal combustion engine, it generates power by burning hydrogen through changes to the fuel supply system, injection system, and fuel, thereby driving the vehicle. It can be simply understood as a hydrogen-burning engine. Its basic principle is the same as that of a regular gasoline or diesel internal combustion engine; it is a basic cylinder-piston type internal combustion engine. One working cycle of engine 10 includes the intake stroke, compression stroke, power stroke, and exhaust stroke. The conversion of chemical energy into mechanical energy is completed in these four strokes of one working cycle.

[0055] When an engine (gasoline engine) is running, the timing of ignition has a significant impact on its performance. Ignition refers to the spark plug igniting the combustible mixture in the combustion chamber during the compression stroke, before the piston reaches top dead center (TDC). The piston's downward stroke is the power stroke. The angle through which the crankshaft rotates from ignition to TDC is called the ignition angle. The ignition angle that achieves optimal power, fuel economy, and emissions is called the optimal ignition angle. The unit for the ignition angle is degrees (°).

[0056] Combination Figure 1 and Figure 2 In the middle, the intake pipe 20 is connected to the intake manifold 11 of the engine 10 and is used to supply hydrogen fuel to the engine 10.

[0057] In the intake direction of the intake manifold 20: the air filter 21 filters the hydrogen fuel, removing dust and sand particles to ensure sufficient clean gas enters the cylinder; the first turbocharger 22 pre-compresses the hydrogen fuel before it enters the cylinder, increasing the engine's intake air density and power output; the intercooler lowers the temperature of the high-temperature air after turbocharging, reducing the engine's thermal load, increasing intake volume, and thus increasing engine power; the throttle valve 24 is a controllable valve that controls the air entering the engine, connected to the air filter above and the engine block below, and is often referred to as the "throat" of the car engine. As an example, the first turbocharger 22 uses turbocharging; in other embodiments, the turbocharging type of this application is not limited to turbocharging.

[0058] The gas injection device 40 can be installed at different positions on the engine 10, combined with Figure 1 As shown, if a gas injection module 41 is used, it needs to be installed on the intake manifold 11 of the engine 10, and the hydrogen nozzle of the gas injection module 41 extends into the intake manifold 11. During the working cycle of the engine 10, the hydrogen nozzle of the gas injection module 41 directly injects hydrogen-fuel mixture into the intake manifold 11, and then enters the cylinder combustion chamber 12 through the intake port (not shown in the figure). Figure 2 As shown, if the direct injection module 42 is used, the direct injection module 42 needs to be installed on the engine 10, and the hydrogen nozzle of the direct injection module 42 extends into the cylinder combustion chamber 12 of the engine 10. During the working cycle of the engine 10, the hydrogen nozzle of the fuel injection module 41 directly injects hydrogen-fuel mixture into the cylinder combustion chamber 12, which can realize the direct supply of hydrogen fuel to the cylinder combustion chamber 12.

[0059] The spark plug 13 is located at the ignition port of the cylinder combustion chamber 12 and is used to ignite the cylinder combustion chamber 12, thus determining the ignition timing of the cylinder combustion chamber 12.

[0060] The exhaust pipe 30 is connected to the exhaust manifold 14 of the engine 10 and is used to discharge unburned hydrogen fuel and combustion products in the engine 10.

[0061] Along the exhaust direction of the exhaust pipe 30: the second turbocharger 31 is used to compress the gas in the exhaust pipe 30, increase the exhaust density of the engine, and improve the exhaust direction of the engine exhaust.

[0062] The λ sensor 32 is a gas sensor that detects the oxygen content in engine exhaust gas to measure the excess air coefficient λ. The excess air coefficient, also known as the "excess air coefficient" or "air excess coefficient," is commonly referred to as the "residual air coefficient." It refers to the ratio of the actual amount of air supplied for fuel combustion to the theoretical amount of air, and is an important parameter reflecting the fuel-air ratio. It is commonly represented by the symbol "λ." Its value can be measured using a gas analyzer; in this embodiment, the λ sensor 32 is used. In various furnaces or combustion chambers, to ensure complete combustion of fuel, the actual amount of air supplied must always be greater than the theoretical amount of air (the excess portion is called "excess air"), meaning the excess air coefficient must be greater than 1. Combustion theory and operational experience show that λ that is too large or too small is detrimental to combustion; that is, different combustion equipment has its optimal excess air coefficient value. Specifically, a large λ indicates excessive air supply, while a small λ indicates insufficient air supply. Figure 3 As shown, according to the NOx (nitrogen oxides) emission mechanism of hydrogen fuel cell engines, NOx emissions first increase and then decrease with the increase of the excess air coefficient λ. A relatively low NOx emission level can be achieved when λ ≥ 2. Here, the horizontal axis represents λ, and the vertical axis represents NOx emissions. X The content, in ppm: milligrams per cubic meter.

[0063] An oxidation catalytic converter 33, abbreviated as DOC (Diesel Oxidation Catalyst), is a device installed in the engine exhaust pipe that converts carbon monoxide (CO) and hydrocarbons (HC) in the engine exhaust into harmless water (H2O) and carbon dioxide (CO2) through an oxidation reaction.

[0064] Based on the above embodiments, combined with Figure 1 and Figure 2 As shown, along the exhaust direction L2, after the oxidation catalytic converter 33, a selective catalytic reduction device 34 is also installed on the exhaust pipe 30.

[0065] In some embodiments, the selective catalytic reduction device 34 utilizes selective catalytic reduction (SCR) and is installed in the engine exhaust system. Under the action of a catalyst, it uses a reducing agent (such as NH3, liquid ammonia, urea) to "selectively" react with NOx in the flue gas to generate non-toxic and non-polluting N2 and H2O, thereby reducing exhaust pollution.

[0066] Based on the above embodiments, continue to combine Figure 1 and Figure 2 As shown, along the exhaust direction (indicated by arrow L2 in the figure), after the oxidation catalytic converter 33, a NOx capture device 35 is also installed on the exhaust pipe 30.

[0067] In some embodiments, the NOx capture device 35 may employ a Lean Nox Trap (LNT), a device that reduces nitrogen oxide (NO and NO2) emissions from lean-burn internal combustion engines by adsorption. Used in automobiles, it can effectively capture NOx. X Capture and release and NO X To reduce NO and achieve purification X The purpose.

[0068] In other embodiments, after the oxidizing catalytic converter 33, the exhaust pipe 30 may also be equipped with commonly used aftertreatment technologies, such as Diesel Particulate Filter (DPF), to after-treat the polluting gases in the exhaust pipe 30 and reduce exhaust pollution.

[0069] Based on the above embodiments, continue to combine Figure 1 and Figure 2 As shown, the first turbocharger 22 and the second turbocharger are connected by bearings.

[0070] Based on the above embodiments, the hydrogen fuel cell engine system also includes a controller (not shown in the figure); Figure 1 In this configuration, the controller is connected to the air filter 21, the first turbocharger 22, the intercooler 23, the throttle body 24, the air intake injection module 41, the spark plug 13, the second turbocharger 31, the λ sensor 32, and the oxidation catalytic converter 33, respectively. Figure 1 In this configuration, the controller is also connected to the selective catalytic reduction unit 34 or the NOx capture unit 35; or, in Figure 2 In this configuration, the controller is connected to the air filter 21, the first turbocharger 22, the intercooler 23, the throttle body 24, the direct injection module 42, the spark plug 13, the second turbocharger 31, the λ sensor 32, and the oxidation catalytic converter 33, respectively, and further... Figure 2In addition, the controller is also connected to the selective catalytic reduction unit 34 or the NOx capture unit 35.

[0071] The controller can be the main controller or host computer of the vehicle system, and the microprocessor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, or any combination thereof.

[0072] In existing technologies, when the target torque of a vehicle increases during actual vehicle operation, the amount of hydrogen injected into the engine is usually increased directly. The spark plug is controlled to ignite according to the steady-state optimal spark angle corresponding to the target torque. This ignition method has the problems of low exhaust temperature, poor boost pressure, slow boosting, slow boost pressure and power improvement, and long transient response time.

[0073] Based on this, and building upon the hydrogen fuel engine system provided in the above embodiments, this invention also provides a transient control method for a hydrogen fuel engine system, used to control the hydrogen fuel engine system provided in the above embodiments. This application improves transient response performance and reduces acceleration response time by controlling ignition timing, system pressurization, hydrogen injection, etc., while also avoiding problems such as high NOx emissions, poor combustion stability, and abnormal combustion due to the large variation range of the excess air coefficient λ in hydrogen lean combustion.

[0074] Figure 4 This is a schematic diagram of a transient control method for a hydrogen fuel cell engine system provided in this application; Figure 5 This is the correspondence between the ignition angle and the excess air coefficient λ of the hydrogen fuel cell engine system of this application; Figure 6 This is a comparison diagram of the transient response time of engine torque between existing technologies and the technology provided in this application. Combined with... Figures 1-6 As shown, the transient control method for a hydrogen fuel cell engine system provided in the embodiments of the invention includes:

[0075] S101. Obtain the initial torque and target torque of the vehicle system at the current moment.

[0076] Torque, the torque output from the crankshaft, is a key performance indicator for engine performance. It is measured in Newton-meters (N·m). With a fixed engine power, torque is inversely proportional to engine speed; higher speeds result in lower torque, and lower speeds result in higher torque. Torque represents force, while engine speed represents velocity. The magnitude of torque reflects the vehicle's load capacity within a certain range; higher torque indicates greater force.

[0077] Transient response time refers to the time it takes for a system's output to transition from an initial state to a steady state under a given signal input. Transient response is also known as dynamic response, overcurrent response, or transient response. In this application, transient time refers to the total engine operating time during which the torque of the vehicle system switches from the initial torque to the target torque.

[0078] As an example, when the car is in motion, the controller of the hydrogen fuel cell engine system obtains the initial torque F0 of the vehicle system and the target torque F1 that needs to be switched at the current moment in real time. At the same time, it obtains the steady-state ignition angle θ0 corresponding to the steady state of the target torque F1 set in the system. The steady-state ignition angle is the optimal ignition angle value for the engine to maintain stable operation of the target torque F1, that is, the best ignition angle.

[0079] S102. Compare the target torque with the initial torque.

[0080] S103. When the target torque is greater than the initial torque, control the first turbocharger to increase the hydrogen gas concentration in the engine, and at the same time control the spark plug to ignite at the first ignition angle.

[0081] It should be noted that the embodiments of this application are attached. Figure 5 , Figure 6 , Figure 9 and Figure 10 In the diagram, ① represents the initial state of the vehicle during driving; ③ represents the target state of the vehicle during driving; and ② represents the intermediate state between state ① and state ③. The initial state is characterized by the engine igniting at the initial ignition angle corresponding to the initial torque F0, and the vehicle driving stably at the initial torque F0. The target state is characterized by the engine igniting at the steady-state ignition angle θ0 corresponding to the preset torque F1, and the vehicle driving stably at the target torque F1. The intermediate state represents the state between the initial torque F0 and the target torque F1.

[0082] This application describes the prior art with reference to the present application. In the accompanying drawings, the black solid lines represent the embodiments of the present application, and the gray dashed lines represent the prior art. As shown by the black arrows in the figures, in the initial state ① to the intermediate state ②, the engine ignites θ1 at the first ignition angle, and in the intermediate state ② to the target state ③, the engine ignites θ2 at the second ignition angle, where θ1 < θ0 < θ2.

[0083] Specifically, in combination Figure 1 , Figure 2 , Figure 5 , Figure 6 As shown, in the initial state ①, the controller compares the initial torque F0 and the target torque F1 of the vehicle system at the current moment. When T1 > T0, it indicates that the torque of the vehicle system increases and the vehicle system needs a greater load capacity. As indicated by the black arrow in the figure, during the first transient response T1 of the engine from state ① to ②, the controller controls the first turbocharger 22 on the intake manifold 20 to increase the hydrogen injection quantity of the port injection module 41 or the direct injection module 42, thereby increasing the hydrogen fuel concentration in the engine 10. At the same time, the controller controls the spark plug 13 to ignite at the first ignition angle θ1 before the piston of the engine reaches the top dead center of the compression stroke, igniting the combustible mixture in the cylinder combustion chamber 12. Within the first transient response time T1, the first ignition angle θ1 is set to be less than the steady-state ignition angle θ0. That is, in one working cycle of the engine, while increasing the amount of hydrogen injection, the ignition angle is delayed. By delaying the ignition angle, the concentration of combustible mixture in the cylinder combustion chamber 12 can be increased. After ignition, the exhaust temperature is increased, the boosting capacity of the engine is accelerated, thereby accelerating the increase of torque and shortening the transient response time.

[0084] S104. Real-time acquisition of the excess air coefficient in the exhaust pipe.

[0085] It should be noted that steps 101 and 104 can be performed simultaneously, and the order of these steps is not restricted in this embodiment.

[0086] S105. When the excess air coefficient is less than or equal to the knock boundary value corresponding to the target torque, control the first turbocharger to continue to increase the hydrogen gas concentration in the engine cylinder, and at the same time control the spark plug to ignite at the second ignition angle, so that the vehicle system increases from the initial torque to the target torque.

[0087] Furthermore, combined with Figure 5 As shown by the black solid lines ①→②→③, the λ sensor 32 measures the excess air coefficient λ in the exhaust pipe 30 in real time. The first turbocharger 22 controls the intake air volume of the intake pipe 20. In the state indicated by the black solid lines ①→②, the excess air coefficient λ is enriched to the knock / NOx high emission boundary value λ1, as shown by the λ1 corresponding to state ② in the figure, where λ1 ≥ 2. Combined with... Figure 6As shown, during the second transient response time T2 when the engine switches from state ② (indicated by the black arrow) to state ③, the first turbocharger 22 is further controlled to increase the hydrogen injection mass, continuing to increase the hydrogen injection quantity of the port injection module 41 or the direct injection module 42, further increasing the hydrogen fuel concentration in the engine 10. Simultaneously, the spark plug 13 is controlled to ignite at the second ignition angle θ2 before the piston reaches top dead center of compression, igniting the combustible mixture in the cylinder combustion chamber 12. During the second transient response time T2, the second ignition angle θ2 is set to be greater than the steady-state ignition angle θ0. That is, in one working cycle of the engine, while increasing the hydrogen injection quantity, the ignition angle is advanced to the optimal steady-state ignition angle value for the target torque. Since a higher exhaust temperature and a higher boost / intake pressure have been achieved by delaying the ignition angle during the first transient response time T1, advancing the ignition angle during the second transient response time T2 increases the work capacity of the same working fluid, rapidly increases torque, and results in a fast transient response. Figure 6 The solid black lines ②→③ are shown in the middle.

[0088] Combination Figure 6 As shown by the black solid lines ①→②→③ and the gray dashed lines ①→②→③, compared with the prior art, this application delays the ignition angle within the first transient response time T1 of switching the target torque and advances the ignition angle within the second transient response time T2. Within the first transient response time T1 of the transient response time T0 when the vehicle switches from the initial torque F0 to the target torque F1, the exhaust temperature and boosting capacity of the hydrogen fuel cell engine can be rapidly increased, and the transient response time T0 of switching to the target torque F1 can be shortened, where T0=T1+T2.

[0089] It should be noted that the engine performed multiple working cycles within both the first transient response time T1 and the second transient response time T2.

[0090] In summary, the transient control method for a hydrogen fuel cell engine system provided in this application, based on the hydrogen fuel cell engine system, can improve transient response performance and reduce acceleration response time by adjusting the ignition timing, system pressurization, and hydrogen injection control. At the same time, it can also avoid problems such as high NOx emissions, poor combustion stability, and abnormal combustion due to the large variation range of the excess air coefficient in hydrogen lean combustion.

[0091] Figure 7 This is a schematic diagram of another transient control method for a hydrogen fuel cell engine system provided in this application; Figure 8 This is the correspondence between the ignition angle and the excess air coefficient λ of the hydrogen fuel cell engine system of this application; Figure 9 This is a comparison diagram of the transient response time of engine torque between existing technologies and the technology provided in this application; Figure 10 This is a schematic diagram of the late-injection strategy during the working cycle of the engine provided in this application. Wherein, Figure 8 In the graph, the horizontal axis represents the crankshaft angle of the engine, the left vertical axis represents the cylinder pressure of the combustion chamber, and the right vertical axis represents the combustion heat release rate.

[0092] Based on the above embodiments, combined with Figure 2 , Figures 7-9 As shown, for a hydrogen fuel cell engine system with a direct injection module 41, this embodiment of the invention also provides a transient control method for a hydrogen fuel cell engine system, the transient control method comprising:

[0093] S201. Obtain the initial torque and target torque of the vehicle system at the current moment.

[0094] The explanation continues in step 101 of the above embodiments.

[0095] S202. Compare the target torque with the initial torque.

[0096] S203. When the target torque is greater than the initial torque, control the first turbocharger to increase the hydrogen gas concentration in the engine, and at the same time control the spark plug to ignite at the first ignition angle.

[0097] Specifically, continue to combine Figure 1 , Figure 2 , Figure 5 , Figure 6 As shown in steps 102 and 103 of the above embodiments.

[0098] S204. Real-time acquisition of the excess air coefficient in the exhaust pipe 30.

[0099] It should be noted that steps 201 and 204 can be performed simultaneously, and the order of these steps is not restricted in this embodiment.

[0100] S205. When the excess air coefficient is less than or equal to the knock boundary value corresponding to the target torque, the first turbocharger is controlled to continue to increase the hydrogen fuel concentration in the engine cylinder, while the spark plug is controlled to ignite at the second ignition angle. Before the power stroke ends and the exhaust stroke begins in each working cycle of the engine, the direct injection module is controlled to inject hydrogen fuel into the cylinder combustion chamber, while the spark plug is controlled to ignite, so that the vehicle system increases from the initial torque to the target torque.

[0101] Furthermore, combined with Figure 2 and Figure 8 As shown by the black solid lines ①→②→③, the λ sensor 32 measures the excess air coefficient λ in the exhaust pipe 30 in real time. The first turbocharger 22 controls the intake air volume of the intake pipe 20. Under the state of black solid lines ①→②, the excess air coefficient λ is enriched to the knock / NOx high emission boundary value λ1, as shown below. Figure 8 The black solid line in the middle represents state ②, corresponding to λ1, where λ1≥2.

[0102] The in-cylinder warm-up acceleration phase refers to the time it takes for the torque of the vehicle system to increase to the target torque after the spark plug ignites at the second ignition angle, i.e., the second transient response time. An engine's working cycle includes the intake stroke, compression stroke, power stroke, and exhaust stroke; typically, the spark plug ignites once per working cycle. In combination... Figures 8-9 As shown, during the time the engine switches from state ② (indicated by the black dashed arrow) to state ③, in each engine operating cycle, the first turbocharger 22 is controlled to increase the hydrogen injection mass, further increasing the hydrogen injection quantity of the port injection module 41 or the direct injection module 42, and further increasing the hydrogen fuel concentration in the engine 10. Simultaneously, the spark plug 13 is controlled to ignite at the second ignition angle θ2 before the piston reaches top dead center of compression in each engine operating cycle, igniting the combustible mixture in the cylinder combustion chamber 12 for the first time. Also, in each engine operating cycle, the spark plug is controlled to ignite a second time before the power stroke ends and the exhaust stroke begins, as shown... Figure 8 and Figure 9 The transition from state ② to state ③, indicated by the black dashed arrow, can also be called late spraying. Further integration... Figure 11 As shown, this application increases the mass of hydrogen injected later, thereby increasing the number of spark plug ignitions per engine cycle. This rapidly increases exhaust temperature, quickly builds up boost pressure / intake pressure, and achieves a rapid torque increase to the target torque value. Since the hydrogen injection volume during the second ignition is small, it does not affect the main combustion process. Figure 11 As shown, although the total λ decreases due to the increase in hydrogen injection mass, the combustion stability and detonation state of the main combustion process are not affected.

[0103] By employing a method of secondary spark plug ignition in each engine operating cycle, the second transient response time T2 for the transition from state ② to state ③ can be shortened to T. 2’ T 2’ <T2. Combination Figure 11 As shown by the solid black lines ①→②→③ and the solid-dashed black lines ①→②→③', adding a second ignition by the spark plug can rapidly increase the exhaust temperature and boost capacity of the hydrogen fuel cell engine, and further shorten the transient response time T when switching to the target torque. 0’ That is, T 0’ =T1+T 2’ T 0’ <T0.

[0104] Based on the above embodiments, during the in-cylinder heating acceleration phase, the engine includes multiple sequentially executed work cycles. In step S205, for each work cycle of the engine within the second transient response time, the transient control method provided in this application also includes:

[0105] Simultaneously, the second ignition angle of the spark plug is gradually reduced to the steady-state ignition angle corresponding to the target torque in multiple sequential working cycles.

[0106] Specifically, continue to combine Figure 2 , Figures 7-10 As shown, the first transient response time T1 and the second transient response time T 2’ The internal engine has undergone multiple operating cycles. When the engine switches from state ① to state ②, the λ sensor 32 measures the excess air coefficient λ in the exhaust pipe 30 in real time, enriching it to the knock / NOx high emission boundary value λ1. During the second transient response T of the engine from state ② to state ③, 2’ Inside, in combination Figure 8 and Figure 9 As shown, during the time the engine switches from state ② (indicated by the black dashed arrow) to state ③, in each working cycle of the engine, the first turbocharger 22 is controlled to increase the hydrogen injection mass, and the hydrogen injection quantity of the port injection module 41 or the direct injection module 42 is further increased, thus increasing the hydrogen fuel concentration in the engine 10. At the same time, the spark plug 13 is controlled to gradually reduce the second ignition angle θ2 before the piston reaches the top dead center of compression in each working cycle of the engine to the steady-state ignition angle corresponding to the target torque, igniting the combustible mixture in the cylinder combustion chamber 12 for the first time. Simultaneously, in each working cycle of the engine, the spark plug is controlled to ignite a second time before the power stroke ends and the exhaust stroke begins, which can rapidly increase the vehicle system from the initial torque to the target torque, thereby compressing the transient response time of the initial torque increasing to the target torque.

[0107] S206 continues to acquire the excess air coefficient λ in the exhaust pipe in real time.

[0108] S207 controls the boost ratio of the first and second boosters to keep the excess air coefficient λ stable at the knock boundary value corresponding to the target torque.

[0109] Specifically, in combination Figure 1 and Figure 2 As shown, the λ sensor 32 measures the excess air coefficient λ in the exhaust pipe 30 in real time. After the excess air coefficient λ is enriched to the knock / NOx high emission boundary value λ1, the boost ratio of the intake pipe 20 and the second booster 31 is controlled by the first booster 22 to control the exhaust volume as much as possible. Figure 5 and Figure 8 The excess air coefficient λ is stabilized at the knock boundary value corresponding to the target torque, resulting in a lower NOx emission level for the engine.

[0110] Based on the above embodiments, after step S105, the transient control method provided in this application embodiment further includes:

[0111] The spark plugs are controlled to ignite at the steady-state ignition angle corresponding to the target torque in order to maintain the engine's stability at the target torque.

[0112] Figure 11 This is a logic control diagram of a hydrogen fuel cell engine system provided in this application.

[0113] Combination Figures 1-11 As shown below, a specific embodiment is given to illustrate how the transient control method for a hydrogen fuel cell engine system provided in this application increases torque and reduces transient response time during vehicle operation. The transient control method for the hydrogen fuel cell engine system includes:

[0114] S11. Detect the current vehicle torque requirement and measure the excess air coefficient λ in real time. The current engine operating state is ①. Proceed to step S12. The torque requirement is the target torque.

[0115] S12. Determine if the target torque of the vehicle has increased. If yes, proceed to S13; otherwise, proceed to S15.

[0116] Specifically, it determines whether the target torque is greater than the initial torque at the current moment.

[0117] S13. Increase the mass of injected hydrogen, delay the ignition angle, and adjust the pressurization control to enrich the excess air coefficient λ. The goal is to enrich the excess air coefficient λ to the knocking boundary value λ1, i.e., target state ②. Jump to S14.

[0118] Specifically, the delayed ignition angle refers to controlling the spark plug 13 to ignite at the first ignition angle θ1 before the engine piston reaches the top dead center of the compression stroke.

[0119] S14. Increase hydrogen mass, advance the ignition angle, adjust the boost and hydrogen injection mass control λ, with the goal of λ stabilizing at the knock boundary value λ1, advancing the ignition angle to the steady-state optimal value, and increasing the torque to the target value ③. Jump to S12.

[0120] Specifically, the advance ignition angle refers to the second ignition angle θ2 of the spark plug 13 before the piston of the engine reaches the top dead center of the compression stroke.

[0121] S15, End.

[0122] Figure 12 This is a logic control diagram of a hydrogen fuel cell engine system provided in this application.

[0123] Combination Figure 2 , Figures 8-12 As shown, if the in-cylinder direct injection module 42 is used, the transient control method of the hydrogen fuel cell engine system provided in this application embodiment includes:

[0124] S21. Detect the current vehicle torque demand and real-time excess air coefficient λ. The current engine operating state is ①. Jump to S22. The torque demand is the target torque.

[0125] S22. Determine if the target torque of the vehicle has increased. If yes, proceed to S23; otherwise, proceed to S27.

[0126] Specifically, it determines whether the target torque is greater than the initial torque at the current moment.

[0127] S23. Delay the ignition angle, increase the mass of injected hydrogen, and adjust the pressurization control to enrich λ. The goal is to enrich λ to the detonation boundary value, i.e., target state ②. Jump to S24.

[0128] Specifically, the delayed ignition angle refers to controlling the spark plug 13 to ignite at the first ignition angle θ1 before the engine piston reaches the top dead center of the compression stroke.

[0129] S24. Increase the hydrogen injection mass of the main injection and the hydrogen injection mass of the late injection, and gradually advance the ignition angle. The goal is to advance the ignition angle to the steady-state optimal value and increase the torque to the target value ③. Jump to S5.

[0130] Specifically, within each working cycle of the engine, the advance ignition angle refers to the second ignition angle θ2 controlled by the spark plug 13 to ignite before the piston reaches top dead center of the compression stroke.

[0131] S25. Determine whether the torque has reached the target value ③. If yes, jump to S26; otherwise, jump to S24.

[0132] S26. Cancel the late spraying strategy and jump to S22.

[0133] S27, End.

[0134] The transient control method for the hydrogen fuel cell engine system provided in the above embodiments can realize transient control of λ monitoring, turbocharger, spark plug, and hydrogen injection, and shorten the transient time of torque increase when the torque of the on-board system increases.

[0135] Based on the same inventive concept, this invention also provides an on-board system. This on-board system includes a hydrogen fuel cell engine system provided in the above embodiments, and uses the transient control method for the hydrogen fuel cell engine system provided in the above embodiments to control torque. Therefore, this on-board system also has the beneficial effects of the hydrogen fuel cell engine system in the above embodiments. The similarities can be understood by referring to the above explanation of the hydrogen fuel cell engine system and the transient control method for the hydrogen fuel cell engine system, and will not be repeated below.

[0136] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A transient control method for a hydrogen fuel cell engine system, the method being applied to a hydrogen fuel cell engine system, characterized in that, include: The intake pipe connects to the engine's intake manifold; Along the intake direction, an air filter, a first turbocharger, an intercooler, and a throttle valve are sequentially arranged on the intake pipe; A gas injection device includes a port injection module or a direct injection module, wherein the port injection module is disposed on the intake manifold and the hydrogen nozzle of the port injection module extends into the intake manifold. The direct injection module is mounted on the engine, and the hydrogen nozzle of the direct injection module extends into the cylinder combustion chamber of the engine. A spark plug is disposed at the ignition port of the cylinder combustion chamber and is used to ignite the cylinder combustion chamber. The exhaust pipe is connected to the exhaust manifold of the engine. Along the exhaust direction, a second turbocharger, a λ sensor, and an oxidation catalytic converter are sequentially installed on the exhaust pipe; The transient control method for the hydrogen fuel cell engine system includes: Obtain the initial torque and target torque of the vehicle system at the current moment; Compare the target torque with the initial torque; When the target torque is greater than the initial torque, the first turbocharger is controlled to increase the hydrogen fuel concentration in the engine, and the spark plug is controlled to ignite at the first ignition angle. The excess air coefficient in the exhaust pipe is obtained in real time using a λ sensor. When the excess air coefficient is less than or equal to the knock boundary value corresponding to the target torque, the first turbocharger is controlled to continue to increase the hydrogen fuel concentration in the engine cylinder, while the spark plug is controlled to ignite at the second ignition angle, so that the vehicle system increases from the initial torque to the target torque. Wherein, the first ignition angle is smaller than the steady-state ignition angle corresponding to the target torque, and the steady-state ignition angle corresponding to the target torque is smaller than the second ignition angle.

2. The transient control method according to claim 1, characterized in that, Along the exhaust direction, after the oxidative catalytic converter, a selective catalytic reduction device is also provided on the exhaust pipe.

3. The transient control method according to claim 1, characterized in that, Along the exhaust direction, after the oxidizing catalytic converter, a NOx capture device is also installed on the exhaust pipe.

4. The transient control method according to claim 1, characterized in that, The hydrogen fuel cell engine system also includes a controller; The exhaust pipe is also equipped with a selective catalytic reduction device, and the controller is connected to the air filter, the first turbocharger, the intercooler, the throttle body, the port injection module, the spark plug, the second turbocharger, the λ sensor, the oxidative catalytic converter, and the selective catalytic reduction device, respectively; or, the exhaust pipe is also equipped with a NOx capture device, and the controller is connected to the air filter, the first turbocharger, the intercooler, the throttle body, the direct injection module, the spark plug, the second turbocharger, the λ sensor, the oxidative catalytic converter, and the NOx capture device, respectively.

5. The transient control method according to claim 1, characterized in that, The hydrogen fuel cell engine system includes a gas injection device, which includes a direct injection module. One working cycle of the engine includes an intake stroke, a compression stroke, a power stroke, and an exhaust stroke. During the in-cylinder warming and acceleration phase, the transient control method further includes: Before the power stroke ends and the exhaust stroke begins in each working cycle of the engine, the direct injection module is controlled to inject hydrogen fuel into the cylinder combustion chamber, while the spark plug is controlled to ignite. The in-cylinder temperature rise acceleration stage refers to the duration during which the torque of the vehicle system increases to the target torque after the spark plug is ignited at the second ignition angle.

6. The transient control method according to claim 5, characterized in that, During the in-cylinder heating and acceleration phase, the engine comprises multiple sequentially performed working cycles; Controlling the first turbocharger to continue increasing the hydrogen fuel concentration in the engine cylinders, while simultaneously controlling the spark plug to ignite at the second ignition angle, also includes: Simultaneously, the second ignition angle of the spark plug is gradually reduced to the steady-state ignition angle corresponding to the target torque during multiple sequential working cycles.

7. The transient control method according to claim 6, characterized in that, After the on-board system increases from the initial torque to the target torque, the transient control method further includes: The spark plug is controlled to ignite at the steady-state ignition angle corresponding to the target torque.

8. The transient control method according to claim 1, characterized in that, After controlling the first turbocharger to increase the hydrogen fuel concentration in the engine cylinders and simultaneously controlling the spark plugs to ignite at the second ignition angle, the transient control method further includes: Continue to acquire the excess air coefficient in the exhaust pipe in real time; The boost ratio of the first and second boosters is controlled to stabilize the excess air coefficient at the knock boundary value corresponding to the target torque.

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