阅读说明：本技术 一种氢气多次直喷内燃机燃烧控制系统和方法 (combustion control system and method for hydrogen repeated direct injection internal combustion engine ) 是由 张华伟 杨振中 王丽君 郭树满 于 2019-08-27 设计创作，主要内容包括：一种氢气多次直喷内燃机燃烧控制系统,包括进气增压系统,所述进气增压系统与中冷器通过管路连接,所述中冷器与进气管的一端连接,进气管的另一端与气缸的进气口相连,所述气缸的排气口与排气管的一端连接,排气管的分支通过电磁阀与冷却EGR的一端相连,冷却EGR的另一端与进气管的进气分支连接；还包括氢气储存设备,所述氢气储存设备与氢气发生设备连接,氢气发生设备与氢气喷射器连接,所述氢气喷射器伸入到气缸内,所述氢气储存设备和氢气发生设备由线路分别与ECU连接,所述ECU由线路分别与固定在气缸上的点火装置、固定在排气管分支上的电磁阀、固定在发动机飞轮上的曲轴转角传感器相连。采用多次喷射的方法,还可以满足氢内燃机不同功率需求的工况。(a combustion control system of a hydrogen repeated direct injection internal combustion engine comprises an air inlet pressurization system, wherein the air inlet pressurization system is connected with an intercooler through a pipeline, the intercooler is connected with one end of an air inlet pipe, the other end of the air inlet pipe is connected with an air inlet of an air cylinder, an air outlet of the air cylinder is connected with one end of an exhaust pipe, a branch of the exhaust pipe is connected with one end of cooling EGR through an electromagnetic valve, and the other end of the cooling EGR is connected with an air inlet branch of the air inlet pipe; still include hydrogen storage facilities, hydrogen storage facilities is connected with hydrogen generating facilities, and hydrogen generating facilities is connected with the hydrogen sprayer, the hydrogen sprayer stretches into in the cylinder, hydrogen storage facilities and hydrogen generating facilities are connected with ECU by the circuit respectively, ECU links to each other with ignition who fixes on the cylinder, fixes the solenoid valve on the blast pipe branch, fixes the crank angle sensor on the engine flywheel by the circuit respectively. The method of multiple injection is adopted, and the working conditions of different power requirements of the hydrogen internal combustion engine can be met.)

1. A combustion control system of a hydrogen multiple direct injection internal combustion engine is characterized in that: the air cooling system comprises an air inlet supercharging system (1), wherein the air inlet supercharging system (1) is connected with an intercooler (2) through a pipeline, the intercooler (2) is connected with one end of an air inlet pipe (3), the other end of the air inlet pipe (3) is connected with an air inlet (41) of an air cylinder (4), an air outlet (42) of the air cylinder (4) is connected with one end of an exhaust pipe (5), a branch (51) of the exhaust pipe (5) is connected with one end of a cooling EGR (6) through an electromagnetic valve (15), and the other end of the cooling EGR (6) is connected with an air inlet branch (31) of the air inlet pipe (3); still include hydrogen storage equipment (7), hydrogen storage equipment (7) are connected with hydrogen generation equipment (8), and hydrogen generation equipment (8) are connected with hydrogen sprayer (9), in hydrogen sprayer (9) stretched into cylinder (4), hydrogen storage equipment (7) and hydrogen generation equipment (8) are connected with ECU (10) respectively by the circuit, ECU (10) link to each other with ignition (11) of fixing on cylinder (4), solenoid valve (15) of fixing on blast pipe (5) branch (51), crank angle sensor (14) of fixing on the engine flywheel by the circuit respectively.

2. The hydrogen multiple direct injection internal combustion control system of claim 1, wherein: an NOx concentration sensor (12), an oxygen sensor (16) and an exhaust temperature sensor (17) are mounted on the exhaust pipe (5), and the NOx concentration sensor (12), the oxygen sensor (16) and the exhaust temperature sensor (17) are respectively connected with the ECU.

3. A combustion control method of a hydrogen multiple direct injection internal combustion engine is characterized in that: the method comprises the following steps:

(a) A hydrogen injector (9) and an ignition device (11) are installed on an air cylinder (4), an air cylinder air inlet pipe (3) is sequentially connected with an intercooler (2) and an air inlet supercharging system (1), a communicating air pipe is arranged between a branch (31) of the air cylinder air inlet pipe (3) and a branch (51) of an air cylinder exhaust pipe (5), a cooling EGR (6) and an electromagnetic valve (15) are arranged on the communicating air pipe, the electromagnetic valve is connected with an ECU (10), the hydrogen injector (9) is sequentially communicated with a hydrogen generator (8) and a hydrogen storage device (7), the hydrogen generator (8) and the hydrogen storage device (7) are respectively connected with the ECU (10), the ignition device (11) is connected with the ECU (10), a crank angle sensor (14) is installed on a flywheel shell of an engine, and the crank angle sensor (14) is connected with the ECU (10); the ECU (10) executes a judgment program according to information fed back by the crank angle sensor (14), and when the engine is judged to be in an intake stroke stage, the hydrogen is pre-injected after an intake valve is opened and an exhaust valve is closed, namely a hydrogen pre-injection stage K, namely an exhaust valve is opened and then a valve overlap angle alpha is passed, and then the hydrogen is pre-injected;

(b) The ECU (10) controls the hydrogen storage device (7) to supply hydrogen to the hydrogen generation device (8) by detecting the pressure and the hydrogen flow in the hydrogen generation device (8), and simultaneously the ECU (10) controls the injection quantity of the hydrogen by controlling the pulse width J and the pulse interval M of the pre-injection stage, and the hydrogen injector (9) injects the hydrogen into the cylinder (4) to increase the hydrogen content in the cylinder (4);

(c) in the intake stroke stage, the intake supercharging system (1), the intercooler (2) and the cooled EGR (6) work together: the ECU (10) sends a command to the electromagnetic valve (15), the electromagnetic valve (15) controls the cooling EGR (6) to introduce the exhaust gas of the exhaust pipe (5) into the air inlet pipe (3) through the exhaust pipe branch (51) and then into the cylinder (4), the intercooler (2) reduces the temperature of the fresh air compressed by the air inlet supercharging system (1), and the cooling EGR (6) and the intercooler (2) jointly reduce the temperature of the mixed gas entering the cylinder (4);

(d) The ECU (10) executes a determination routine based on information fed back from the crank angle sensor, when it is determined that the engine reaches the compression stroke stage and the main injection condition is satisfied: the main injection is started, then the ECU (10) controls the hydrogen injector (9) to inject, the injection quantity of the hydrogen is controlled by controlling the pulse width L of the main injection, meanwhile, the ECU (10) controls the ignition device (11) to ignite the mixed gas in the cylinder (4), the engine enters an expansion power stroke, and one working cycle is completed.

4. The combustion control method of a hydrogen multiple direct injection internal combustion engine according to claim 3, characterized in that: during the hydrogen pre-injection phase K, multiple injections with a pulse width of the pre-injection pulse width J are performed.

5. The combustion control method of a hydrogen multiple direct injection internal combustion engine according to claim 3, characterized in that: the pre-injection pulse width J is less than the pre-injection phase pulse interval M.

6. The combustion control method of a hydrogen multiple direct injection internal combustion engine according to claim 3, characterized in that: the main injection pulse width L is larger than the pre-injection pulse width J.

7. The combustion control method of a hydrogen multiple direct injection internal combustion engine according to claim 3, characterized in that: an NOx concentration sensor (12), an oxygen sensor (16) and an exhaust temperature sensor (17) are mounted on the exhaust pipe, and the NOx concentration sensor (12), the oxygen sensor (16) and the exhaust temperature sensor (17) are respectively connected with the ECU (10).

Technical Field

The invention relates to a combustion control system and method for a hydrogen repeated direct injection internal combustion engine, and belongs to the technical field of hydrogen fuel engines.

Background

The global energy supply based on fossil fuel is facing more and more serious challenges, the environmental pollution problem caused by using fossil fuel is receiving social attention, and the emission regulation is increasingly strict. The hydrogen energy is the cleanest energy which is most widely distributed in the universe and has permanent resource regeneration, and the hydrogen energy is taken as an ideal alternative energy of the traditional fossil fuel, which is a consensus of scientists. The hydrogen internal combustion engine can depend on a mature internal combustion engine industrial system, has low requirement on hydrogen purity, ultralow emission and higher thermal efficiency, can flexibly utilize other fuels, does not depend on noble metal materials and the like, and becomes one of the main choices of the future vehicle power. The unique characteristics of hydrogen make it a challenging but promising fuel for internal combustion engine applications compared to traditional liquid fuels such as gasoline and gaseous fuels such as methane.

The utility value of a hydrogen internal combustion engine depends on the combustion characteristics of hydrogen gas. Compared with fossil fuel, the hydrogen has fast burning speed, good diffusibility, wide ignition limit and low ignition energy. However, hydrogen internal combustion engines also face abnormal combustion problems such as combustion cycle variation, pre-ignition, flashback, and the like, which affect combustion efficiency and emission performance.

With respect to combustion control of hydrogen internal combustion engines, current research is mainly focused on how to solve the trade-off relationship of high thermal efficiency and high NOx emission. Theoretically, the hydrogen combustion product is water only, and there is only a single NOx in the hydrogen engine exhaust pollutants, regardless of the very low pollutants produced by the combustion of the lubricating oil. With the focus on improving thermal efficiency and controlling NOx emissions, hydrogen internal combustion engine mixture control has evolved gradually from pfi (port Fuel injection) to di (direct injection) injection technologies. Because hydrogen has the characteristic of wide ignition range, the condition that the hydrogen is abnormally combusted needs to be avoided when the direct-injection hydrogen internal combustion engine combusts. The existing direct injection technology of the hydrogen internal combustion engine mainly takes single injection as a main technology and directly injects hydrogen into a cylinder.

Disclosure of Invention

The existing direct injection technology of the hydrogen internal combustion engine mainly takes single injection as a main technology and directly injects hydrogen into a cylinder. The method has short hydrogen mixing time and poor mixing uniformity; meanwhile, the hydrogen density is low, the requirement on an injector is high, the hydrogen can be injected into the cylinder at higher injection pressure, the control strategy of the existing hydrogen direct injection technology of the internal combustion engine is simple, and the hydrogen injection is not easy to control; in addition, the total amount of hydrogen entering the cylinder is slightly less due to single injection, and the power density is not easy to improve.

The technical problems to be solved by the invention are as follows: the injection control method of the direct-injection hydrogen internal combustion engine is improved, the mixing uniformity of the hydrogen is improved, the mixing time of the hydrogen and air is prolonged, the hydrogen is mixed more fully and burnt more thoroughly, and the power density of the hydrogen internal combustion engine is improved; the probability of occurrence of the abnormal combustion phenomenon of the hydrogen internal combustion engine is reduced by improving the method for controlling the abnormal combustion of the hydrogen gas.

The technical scheme of the invention is as follows:

a combustion control system of a hydrogen repeated direct injection internal combustion engine comprises an air inlet pressurization system, wherein the air inlet pressurization system is connected with an intercooler through a pipeline, the intercooler is connected with one end of an air inlet pipe, the other end of the air inlet pipe is connected with an air inlet of an air cylinder, an air outlet of the air cylinder is connected with one end of an exhaust pipe, a branch of the exhaust pipe is connected with one end of cooling EGR through an electromagnetic valve, and the other end of the cooling EGR is connected with an air inlet branch of the air inlet pipe; still include hydrogen storage facilities, hydrogen storage facilities is connected with hydrogen generating facilities, and hydrogen generating facilities is connected with the hydrogen sprayer, the hydrogen sprayer stretches into in the cylinder, hydrogen storage facilities and hydrogen generating facilities are connected with ECU by the circuit respectively, ECU links to each other with ignition who fixes on the cylinder, fixes the solenoid valve on the blast pipe branch, fixes the crank angle sensor on the engine flywheel by the circuit respectively.

in the hydrogen multiple direct injection internal combustion control system, the exhaust pipe is provided with the NOx concentration sensor, the oxygen sensor and the exhaust temperature sensor, and the NOx concentration sensor, the oxygen sensor and the exhaust temperature sensor are respectively connected with the ECU.

A combustion control method of a hydrogen multiple direct injection internal combustion engine comprises the following steps:

(a) The method comprises the following steps that a hydrogen injector and an ignition device are installed on an air cylinder, an air inlet pipe of the air cylinder is sequentially connected with an intercooler and an air inlet supercharging system, a communicating air pipe is arranged between a branch of the air inlet pipe of the air cylinder and a branch of an air outlet pipe of the air cylinder, cooling EGR and an electromagnetic valve are arranged on the communicating air pipe, the electromagnetic valve is connected with an ECU (electronic control unit), the hydrogen injector is sequentially communicated with a hydrogen generator and hydrogen storage equipment, the hydrogen generator and the hydrogen storage equipment are respectively connected with the ECU, the ignition device is connected with the ECU, a crank angle sensor is installed on; the ECU executes a judgment program according to information fed back by the crank angle sensor, and when the engine is judged to be in an intake stroke stage, the hydrogen is pre-injected after an intake valve is opened and an exhaust valve is closed, namely a hydrogen pre-injection stage K, namely an exhaust valve is opened and the hydrogen is pre-injected after a valve overlap angle alpha is passed;

(b) The ECU controls the hydrogen storage device to provide hydrogen to the hydrogen generation device by detecting the pressure and the hydrogen flow in the hydrogen generation device, and simultaneously controls the injection quantity of the hydrogen by controlling the pulse width J and the pulse interval M of the pre-injection stage, so that the hydrogen is injected into the cylinder by the hydrogen injector, and the hydrogen content in the cylinder is increased;

(c) During the intake stroke, the intake boost system, the intercooler and the cooled EGR work together: the ECU sends an instruction to the electromagnetic valve, the electromagnetic valve controls cooling EGR to introduce exhaust gas of the exhaust pipe into the air inlet pipe through the exhaust pipe branch and then enter the air cylinder, the intercooler reduces the temperature of fresh air compressed by the air inlet supercharging system, and the cooling EGR and the intercooler reduce the temperature of mixed gas entering the air cylinder together; the ECU executes a judgment program according to information fed back by the crank angle sensor, and when it is judged that the engine reaches the compression stroke stage and the main injection condition is satisfied: and after the main injection is started, the ECU controls the hydrogen injector to inject, the injection quantity of the hydrogen is controlled by controlling the pulse width L of the main injection, meanwhile, the ECU controls the ignition device to ignite the mixed gas in the cylinder, the engine enters an expansion power stroke, and one working cycle is completed.

In the combustion control method for the hydrogen multiple direct injection internal combustion engine, in the hydrogen pre-injection phase K, multiple injections with the pulse width of the pre-injection pulse width J are performed.

In the combustion control method of the hydrogen multiple direct injection internal combustion engine, the pre-injection pulse width J is smaller than the pulse interval M in the pre-injection stage.

according to the combustion control method of the hydrogen multi-time direct injection internal combustion engine, the main injection pulse width L is larger than the pre-injection pulse width J.

In the combustion control method of the hydrogen multiple direct injection internal combustion engine, the exhaust pipe is provided with the NOx concentration sensor, the oxygen sensor and the exhaust temperature sensor, and the NOx concentration sensor, the oxygen sensor and the exhaust temperature sensor are respectively connected with the ECU.

Compared with the prior art, the invention has the beneficial effects that: the invention provides a combustion control system and a method of a hydrogen multiple direct injection internal combustion engine, wherein hydrogen is injected in advance in an intake stroke, and the quantity of the hydrogen entering a cylinder is increased by multiple injection, so that the mixing uniformity of the hydrogen and air is improved, the total quantity of the hydrogen during combustion is increased, and the power density is improved; the method has the advantages that hydrogen is sprayed in advance when the temperature in the cylinder is low in the intake stroke stage, and then the intake pressurization system, the intercooler and the cooling EGR are introduced to work together, so that the combustion temperature is reduced, the phenomenon of abnormal combustion of the hydrogen is avoided, and the potential of reducing NOx emission is realized; the method of multiple injection is adopted, and the working conditions of different power requirements of the hydrogen internal combustion engine can be met.

Drawings

FIG. 1 is a schematic diagram of the system of the present invention.

Fig. 2 is a partial schematic view of the cylinder shown in fig. 1.

fig. 3 is a schematic diagram of the hydrogen direct injection multiple injection process of the present invention.

Fig. 4 is a multi-pulse injection schematic.

Fig. 5 is a flow chart of the working steps of the present invention.

Detailed Description

as shown in fig. 1-2, a combustion control system for a hydrogen multiple direct injection internal combustion engine includes: the system comprises an air inlet supercharging system 1, wherein the air inlet supercharging system 1 is connected with an intercooler 2 through a pipeline, the intercooler 2 is connected with one end of an air inlet pipe 3, the other end of the air inlet pipe 3 is connected with an air inlet 41 of an air cylinder 4, an air outlet 42 of the air cylinder 4 is connected with one end of an exhaust pipe 5, a branch 51 of the exhaust pipe 5 is connected with one end of a cooling EGR6 through an electromagnetic valve 15, the other end of the cooling EGR6 is connected with an air inlet branch 31 of the air inlet pipe 3, exhaust gas is introduced from the branch 51 of the exhaust pipe 5, is cooled through the cooling EGR6, enters the air inlet pipe 3 through an air inlet branch 31, is mixed with fresh air provided by the air inlet supercharging system 1 in the air inlet pipe 3 and then enters the air cylinder 4, the temperature and the oxygen content in the air; the device is characterized by further comprising a hydrogen storage device 7, the hydrogen storage device 7 is connected with a hydrogen generation device 8, the hydrogen generation device 8 is connected with a hydrogen injector 9, the hydrogen injector 9 extends into the cylinder 4, the hydrogen storage device 7 and the hydrogen generation device 8 are respectively connected with an ECU10 through lines, hydrogen in the hydrogen storage device 7 and the hydrogen generation device 8 is controlled by the ECU10, the ECU10 controls hydrogen in the hydrogen generation device to reach the hydrogen injector 9 through a pipeline, the hydrogen injector 9 is fixed on the cylinder 4, and an injection nozzle of the hydrogen injector 9 injects hydrogen into the cylinder 4; the ECU10 is respectively connected with an ignition device 11 fixed on the cylinder 4, an electromagnetic valve 15 fixed on a branch 51 of the exhaust pipe 5, a crank angle sensor 14 fixed on an engine flywheel, a NOx concentration sensor 12 installed on the exhaust pipe 5, an oxygen sensor 16 installed on the exhaust pipe 5 and an exhaust temperature sensor 17 installed on the exhaust pipe 5 through lines, the ECU10 receives information of the hydrogen storage device, the hydrogen generating device, the electromagnetic valve and the crank angle sensor and simultaneously sends instructions to the ignition device and the hydrogen generating device, and hydrogen of the hydrogen generating device is injected into or stopped from being injected into the cylinder through the hydrogen injection device and is combined with the ignition device to complete an ignition or flameout procedure.

Before the stage of the intake stroke of the engine, the ECU10 determines the working stroke of the engine based on the crank angle position of the engine. In the intake stroke stage, an intake valve is opened, an exhaust valve is closed, at the moment, an ECU10 sends an instruction and a hydrogen injector 9 injects a proper amount of hydrogen into the cylinder 4, so that the mixing time of the hydrogen and the air is prolonged, the mixing uniformity is improved, and the power density of the hydrogen internal combustion engine is increased; at the end of the subsequent compression stroke, the ECU10 sends a command and the hydrogen injector 9 injects a large amount of hydrogen into the cylinder 4 again to form a rich mixture condition, and multiple injections of one working cycle are completed. Because the first injection of the hydrogen is carried out in the air intake stage, the pressure in the cylinder 4 is low at the moment, the requirement on the injection pressure is low, the temperature in the cylinder 4 is low, abnormal combustion is not easy to generate, the mixing time of the hydrogen and the air is increased from the air intake stroke to the compression stroke, the mixed gas is more uniform, the hydrogen can be fully combusted in the subsequent compression process, and the reduction of the NOx emission amount of combustion pollutants is facilitated. The cooled EGR6 controlled by the electromagnetic valve 15 can lead the exhaust gas of the exhaust pipe 5 into the air inlet pipe 3 through the exhaust pipe branch 51 after being cooled, and then the exhaust gas enters the cylinder 4, the intercooler 2 can reduce the temperature of the fresh air compressed by the air inlet supercharging system 1, and the cooled EGR6 and the intercooler 2 jointly reduce the temperature of the mixed gas entering the cylinder 4; the ECU10 controls the hydrogen storage device 7 to supply hydrogen to the hydrogen generation device 8 and the hydrogen injector 9 to inject hydrogen into the cylinder 4 by detecting the pressure and flow rate of the hydrogen generation device 8, thereby increasing the hydrogen content in the cylinder 4. During the intake stroke, the intake boost system 1, intercooler 2 and cooled EGR6 work together: the ECU10 sends a command to the electromagnetic valve 15, the electromagnetic valve 15 controls the cooling EGR6 to introduce the exhaust gas of the exhaust pipe 5 into the air inlet pipe 3 through the exhaust pipe branch 51 and then enter the air cylinder 4, the intercooler 2 reduces the temperature of the fresh air compressed by the air inlet supercharging system 1, and the cooling EGR6 and the intercooler 2 jointly reduce the temperature of the mixed gas entering the air cylinder 4; the ECU10 controls the hydrogen storage device 7 to supply hydrogen to the hydrogen generating device 8 by detecting the pressure and the hydrogen flow rate in the hydrogen generating device 8, and simultaneously the ECU10 controls the hydrogen generating device 8 to input the injection amount of the hydrogen to the hydrogen injector by controlling the pre-injection pulse width J and the pre-injection stage pulse interval M, so that the hydrogen injector 9 injects the hydrogen into the cylinder 4 to increase the hydrogen content in the cylinder 4. The intake air quantity of the hydrogen is increased while the intake air temperature is reduced, abnormal combustion of the hydrogen injected into the cylinder 4 in advance is avoided, and the improvement of the injection quantity of the hydrogen and the power density of the engine is facilitated.

The combustion control method of the hydrogen repeated direct injection internal combustion engine comprises the following specific steps:

As shown in FIG. 3, A represents intake valve opening, B represents intake valve closing, C represents exhaust valve opening, D represents exhaust valve closing, E represents top dead center, F represents bottom dead center, G represents the pre-hydrogen injection phase, and α represents the valve overlap angle.

As shown in FIG. 4, J represents the pilot injection pulse width, M represents the pilot injection stage pulse interval, K represents the N multiple pulse pilot injection stages, L represents the main injection pulse width, Q represents the multiple pulse injection timing, and P represents the main injection angle.

As shown in fig. 1-5, a hydrogen injector 9 and an ignition device 11 are installed on a cylinder 4, a cylinder intake pipe 3 is sequentially connected with an intercooler 2 and an intake supercharging system 1, a communication pipe is arranged between a branch 31 of the cylinder intake pipe 3 and a branch 51 of a cylinder exhaust pipe 5, a cooling EGR6 and an electromagnetic valve 15 are arranged on the communication pipe, the electromagnetic valve is connected with an ECU10, the hydrogen injector 9 is sequentially connected with a hydrogen generating device 8 and a hydrogen storage device 7, the hydrogen generating device 8 and the hydrogen storage device 7 are respectively connected with the ECU10, the ignition device 11 is connected with the ECU10, a crank angle sensor 14 is installed on a flywheel housing of the engine, and the crank angle sensor 14 is connected with the ECU 10.

The present invention further mounts a NOx concentration sensor 12, an oxygen sensor 16, and an exhaust gas temperature sensor 17 on the exhaust pipe, and the NOx concentration sensor 12, the oxygen sensor 16, and the exhaust gas temperature sensor 17 are connected to the ECU10, respectively. The control unit ECU of the engine adjusts the time and the injection pulse width of the direct injection of the hydrogen of the internal combustion engine according to the working conditions of the engine, the working parameters collected by the NOx concentration sensor 12, the oxygen sensor 16, the exhaust temperature sensor 17, the crank angle sensor and other sensors so as to meet different power requirements, the other sensors comprise at least one of an air flow sensor, an intake pressure sensor, an intake temperature sensor and an engine water temperature sensor fixed in a cylinder body, the air flow sensor, the intake pressure sensor, the intake temperature sensor and the engine water temperature sensor are arranged on an air inlet pipe, and the sensors are all connected with.

The start phase is a process in which the ECU10 first executes a determination routine based on information fed back from the crank angle sensor 14, and when it is determined that the engine is in the intake stroke phase, hydrogen is pre-injected after the intake valve a of the cylinder is opened and the exhaust valve D is closed, i.e., the hydrogen pre-injection phase K, i.e., after the exhaust valve C is opened, after the valve overlap angle α, hydrogen pre-injection is started.

The ECU10 controls the hydrogen storage device 7 to supply hydrogen to the hydrogen generation device 8 by detecting the pressure and the hydrogen flow rate in the hydrogen generation device 8, and simultaneously the ECU10 controls the injection amount of the hydrogen by controlling the pre-injection pulse width J and the pre-injection stage pulse interval M, and the hydrogen injector 9 injects the hydrogen into the cylinder 4 to increase the hydrogen content in the cylinder 4; in the hydrogen pre-injection stage K, a plurality of injection processes with pulse width of pre-injection pulse width J are carried out, the pre-injection pulse width J is smaller than the pulse interval M of the pre-injection stage, and the main injection pulse width L is larger than the pre-injection pulse width J.

In the intake stroke stage, the phenomenon of premature combustion of hydrogen caused by relatively high exhaust temperature due to the existence of the valve overlap angle alpha can be reduced by pre-injecting the hydrogen; on the other hand, the temperature of the mixed gas in the cylinder 4 is reduced by the aid of the common work of the air inlet pressurization system 1, the intercooler 2 and the cooling EGR6, the ECU10 controls the hydrogen injector 9 to inject hydrogen into the cylinder 4, so that the content of the hydrogen in the cylinder 4 is increased, the air inlet temperature is reduced, the air inlet amount of the hydrogen is increased, abnormal combustion of the hydrogen injected into the cylinder 4 in advance is avoided, meanwhile, the working media in the cylinder 4 are mixed more fully, and the improvement of the hydrogen injection amount and the power density of an engine is facilitated.

And then the ECU10 executes a judgment program according to the information fed back by the crank angle sensor 14, when the engine is judged to reach the compression stroke and meet the main injection condition, the main injection is started, then the ECU10 controls the hydrogen injector 9 to inject, controls the injection amount of the hydrogen by controlling the pulse width L of the main injection, simultaneously the ECU10 controls the ignition device 11 to ignite the mixed gas in the cylinder 4, and the engine enters the expansion power stroke and completes one working cycle.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the overall concept of the present invention, and these should also be considered as the protection scope of the present invention.