阅读说明：本技术 一种复合喷射氢发动机及控制方法 (Compound hydrogen injection engine and control method ) 是由 纪常伟 辛固 汪硕峰 常珂 孟昊 杨金鑫 于 2021-08-02 设计创作，主要内容包括：本发明为一种复合喷氢发动机及控制方法,具体涉及一种进气道喷射与缸内直喷相结合的复合喷射氢发动机及控制方法。该发动机包括进气系统、高压供氢系统、低压供氢系统、缸内喷水系统和电控系统。根据发动机功率需求及工作状态调节直喷氢气和进气道喷氢比例,同时调节接气门开度控制进气量,从而控制发动机的功率输出。ECU通过曲轴位置传感器和转速传感器判断曲轴位置和转速,并根据爆震传感器信号判断爆震发生。根据爆震信号调节水泵压力和喷水器的喷射脉宽,控制早燃、回火和爆震等异常燃烧问题。该发动机及控制方法可以实现发动机灵活的调节特性,并能消除氢发动机的爆震,降低氮氧化物排放,提高氢发动机的效率。(The invention relates to a compound hydrogen injection engine and a control method, in particular to a compound hydrogen injection engine combining air inlet channel injection and in-cylinder direct injection and a control method. The engine comprises an air inlet system, a high-pressure hydrogen supply system, a low-pressure hydrogen supply system, an in-cylinder water injection system and an electric control system. The proportion of direct injection hydrogen and air inlet channel injection hydrogen is adjusted according to the power requirement and the working state of the engine, and the air inlet opening is adjusted to control the air inlet amount, so that the power output of the engine is controlled. The ECU judges the position and the rotating speed of the crankshaft through a crankshaft position sensor and a rotating speed sensor, and judges the occurrence of knocking according to a signal of a knock sensor. And regulating the pressure of a water pump and the injection pulse width of a water sprayer according to the detonation signal, and controlling abnormal combustion problems such as pre-ignition, backfire and detonation. The engine and the control method can realize the flexible regulation characteristic of the engine, eliminate the knocking of the hydrogen engine, reduce the emission of nitrogen oxides and improve the efficiency of the hydrogen engine.)

1. A compound injection hydrogen engine characterized by: the device comprises an air inlet system (P1), an air flow sensor (9), a throttle valve (8), an air filter (7), a low-pressure hydrogen supply system (P2), a hydrogen bottle (1), a low-pressure hydrogen reducing valve (3), a low-pressure hydrogen flow sensor (4), an air inlet channel hydrogen ejector (11), a high-pressure hydrogen supply system (P3), a hydrogen bottle (2), a high-pressure hydrogen reducing valve (5), a high-pressure hydrogen flow sensor (6), an in-cylinder direct injection hydrogen ejector (12), an in-cylinder water spraying system (P4), a water tank (19), a high-pressure water pump (18), a water flow sensor (17), a water ejector (16), a control system (P5), and the like, wherein the air inlet system comprises an ECU (13), a spark plugs (15), a crankshaft position sensor (10), a rotating speed sensor (20), and a flow rate sensor (20), A knock sensor (14);

the ECU (13) is in signal interaction with an air flow sensor (9), a throttle valve (8), a low-pressure hydrogen pressure reducing valve (3), a low-pressure hydrogen flow sensor (4), an air inlet channel hydrogen injector (11), a high-pressure hydrogen pressure reducing valve (5), a high-pressure hydrogen flow sensor (6), an in-cylinder direct injection hydrogen injector (12), a high-pressure water pump (18), a water flow sensor (17), a water injector (16), a spark plug (15), a crankshaft position sensor (10), a rotating speed sensor (20) and a knock sensor (14) respectively;

the ECU (13) is connected with a throttle valve (8) and an air flow sensor (9) through leads, the opening of the throttle valve is controlled by sending out a throttle valve control signal, and the air flow sensor (9) monitors the air flow and feeds back the signal to the ECU (13) so as to correct the air inflow entering an engine cylinder;

the ECU (13) is connected with a rotating speed sensor (20) and a crankshaft position sensor (10) through leads to judge the rotating speed and the compression top dead center position of the engine and provide data reference for controlling the spraying time and the pulse width of the hydrogen and water;

the ECU (13) is connected with the low-pressure hydrogen reducing valve (3) through a lead and adjusts the low-pressure hydrogen reducing valve (3) according to a throttle control signal so as to control the injection pressure at the position of the gas inlet channel hydrogen injector (11);

the ECU (13) is connected with the low-pressure hydrogen flow sensor (3) and the air inlet channel hydrogen injector (11) through a lead, the ECU (13) adjusts the injection time and the injection pulse width of the air inlet channel hydrogen injector (11) according to a throttle control signal and a crankshaft position signal, and the feedback signal of the low-pressure hydrogen flow sensor (4) is used for correcting so as to ensure the stability of an excess air coefficient;

the ECU (13) is connected with the low-pressure hydrogen reducing valve (3) through a lead and adjusts the low-pressure hydrogen reducing valve (3) according to a throttle control signal so as to control the injection pressure at the position of the gas inlet channel hydrogen injector (11);

the ECU (13) is connected with the high-pressure hydrogen pressure reducing valve (5) and the in-cylinder direct injection hydrogen injector (12) through a lead, the ECU (13) adjusts the injection time and the injection pulse width of the in-cylinder direct injection hydrogen injector (12) according to a throttle control signal and a crankshaft position signal, and the feedback signal of the high-pressure hydrogen flow sensor (6) is used for correcting so as to ensure the stability of an excess air coefficient;

the ECU (13) is connected with a knock sensor (14) through a lead, and judges whether knocking occurs or not according to an output signal of the knock sensor (14);

the ECU (13) is connected with the high-pressure water pump (18) through a lead, and adjusts the output pressure of the high-pressure water pump according to the rotating speed of the engine and the opening signal of the throttle valve so as to adjust the injection pressure at the water injector;

the ECU (13) is connected with a water flow sensor (17) and a water injector (16) through leads, and the ECU (13) adjusts the injection time and the injection pulse width of the water injector according to a knock signal and a crankshaft position signal;

the ECU (13) is connected to an ignition plug (15) by a wire, and adjusts the ignition timing based on a throttle opening signal, a crank position sensor signal, a rotational speed sensor signal, and a knock sensor signal.

2. A compound injection hydrogen engine and control method using the method as claimed in claim 1, the method comprising a fueling strategy and a combustion control strategy, characterized in that:

(1) fuel delivery strategy

a. Starting condition

The ECU (13) receives a signal of a rotating speed sensor (20), when the rotating speed n is equal to 0 and becomes n is not equal to 0, the starting working condition is adopted, for smooth starting, an air inlet channel injection strategy is adopted, the ECU (13) controls a low-pressure hydrogen reducing valve (3), an air inlet channel hydrogen injector (11) and a throttle valve (8), the hydrogen supply quantity and the air quantity are adjusted, correction is carried out according to feedback signals of a low-pressure hydrogen flow sensor (4) and an air flow sensor (9), and the excess combustion air coefficient lambda is kept to be 1;

b. idling condition

The ECU (13) receives the signal of the rotation speed sensor (20) and detects the rotation speed n_{Idling speed}-50<n<n_{Idling speed}At +50, in the idling working condition, an air inlet channel hydrogen injection strategy is adopted, an ECU (13) controls a low-pressure hydrogen pressure reducing valve (3), an air inlet channel hydrogen injector (11) and a throttle valve (8), the hydrogen supply amount and the air amount are adjusted, correction is carried out according to feedback signals of a low-pressure hydrogen flow sensor (4) and an air flow sensor (9), and the combustion excess air coefficient lambda is kept to be 1.5;

c. low speed low load operating mode

The ECU (13) receives the signal of the rotation speed sensor (20) and detects the rotation speed n_{Idling speed}+50＜n＜2×n_{Idling speed}And the engine power demand P<30％×P_{Forehead (forehead)}At the moment, under the low-speed and low-load working condition, an air inlet channel hydrogen injection strategy is adopted, an ECU (13) controls a low-pressure hydrogen pressure reducing valve (3) and an air inlet channel hydrogen injector (11) according to power requirements, the supply quantity of low-pressure hydrogen is adjusted, and correction is carried out according to a feedback signal of a low-pressure hydrogen flow sensor (4) so as to ensure the stability of an excess air coefficient;

d. low speed medium and large load operating mode

The ECU (13) receives the signal of the rotation speed sensor (20) and detects the rotation speed n_{Idling speed}+50＜n＜2×n_{Idling speed}And the power demand P of the engine is more than or equal to 30% multiplied by P_{Forehead (forehead)}At this time, the speed is low or mediumUnder a large load working condition, a direct injection hydrogen strategy is adopted. The ECU (13) controls the high-pressure hydrogen pressure reducing valve (5) and the in-cylinder direct injection hydrogen injector (12) according to signals of a throttle sensor, adjusts the supply amount of high-pressure hydrogen, and corrects according to feedback signals of a high-pressure hydrogen flow sensor (6) to ensure that the excess air coefficient is stable;

e. medium and high speed working condition

The ECU (13) receives the signal of the rotation speed sensor (20) and detects the rotation speed of 2 Xn_{Idling speed}N is less than or equal to n, and at the moment, the hydrogen supply strategy combining air inlet channel injection and in-cylinder direct injection is adopted. The ECU (13) controls the low-pressure hydrogen pressure reducing valve (3) and the air inlet channel hydrogen injector (11) according to signals of a throttle sensor, adjusts the supply amount of low-pressure hydrogen, and corrects according to feedback signals of a low-pressure hydrogen flow sensor (4) to ensure that the excess air coefficient is stable; the ECU (13) controls the high-pressure hydrogen pressure reducing valve (5) and the in-cylinder direct injection hydrogen injector (12) according to signals of a throttle sensor, adjusts the supply amount of high-pressure hydrogen, and performs feedback adjustment according to the high-pressure hydrogen flow sensor (6); according to a throttle sensor signal of the engine, the proportion beta of the hydrogen injected from the air inlet channel to the hydrogen injected directly into the cylinder is adjusted, and the beta is regulated and controlled from 0 to 50% along with the increase of the throttle sensor signal;

wherein n is_{Idling speed}Calibrating the idling speed, P, for the engine_{Forehead (forehead)}Rated power for the engine;

β＝m_{direct injection in cylinder}/(m_{Air inlet channel}+m_{Direct injection in cylinder}) In the formula, m_{Direct injection in cylinder}、m_{Air inlet channel}The mass flow rates of direct-injection hydrogen in the cylinder and the mass flow rate of hydrogen injection in the air inlet channel are respectively;

excess air ratio of combustion process mixtureIn the formula (I), the compound is shown in the specification, wherein m is_air、Fresh air mass flow and total hydrogen mass flow,is the stoichiometric air-fuel ratio of hydrogen;

(2) combustion control strategy

The ECU (13) receives a signal of the knock sensor (14), and if the knock sensor (14) judges that no knock occurs, the ECU controls the ignition of the spark plug according to a torque demand to keep the ignition time at the optimal ignition angle;

the ECU (13) receives a signal of the knock sensor (14), and if the knock sensor (14) judges that knocking occurs, the ECU (14) controls the spark plug (16) to delay the ignition time until the knocking does not occur;

if the ignition is delayed until the top dead center, the detonation can not be eliminated, the ECU (13) controls the high-pressure water pump (18) and the water injector (16), controls the water injection quantity by adjusting the injection pulse width, and gradually increases from 0 until the detonation is eliminated, and then the current water injection quantity is maintained to be unchanged under the working condition.

Technical Field

A composite hydrogen injection engine and a control method thereof, in particular to a spark ignition engine combining hydrogen injection in an air inlet passage and hydrogen injection in a cylinder and a control method thereof, belonging to the field of internal combustion engines.

Background

In recent years, with the rapid expansion of automobile holding capacity, the pressure of 'carbon peak reaching' and 'carbon neutralization' is increasing in the traffic industry of China, and the emission of various pollutants caused by the combustion of fossil fuels by automobile engines is more and more prominent, so that the development of alternative fuel technology is receiving wide attention.

The hydrogen is a renewable fuel, has wide source, can be prepared by electrolyzing water, and can play a role in regulating peak clipping and valley leveling. Hydrogen has excellent combustion characteristics such as short quenching distance, fast combustion speed, low minimum ignition energy, wide flammability limit, etc., and thus is suitable as a fuel for internal combustion engines.

The prior hydrogen engine mainly adopts a gas inlet channel to inject hydrogen, and the hydrogen is premixed with air and then supplied into a cylinder, but the prior hydrogen engine faces abnormal combustion phenomena such as pre-ignition, backfire and detonation at a higher equivalence ratio, thereby limiting the practical application of the hydrogen engine. And operating at higher equivalence ratios, the nitrogen oxide emission levels of hydrogen engines increase dramatically. The technique of controlling abnormal combustion mainly employs an EGR (exhaust gas recirculation) strategy, but the EGR strategy causes an increase in intake air temperature, decreases the volumetric efficiency of the cylinder, and causes a decrease in power and efficiency. The current researchers propose to adopt a strategy of direct hydrogen injection in the cylinder to eliminate the backfire problem, and since higher injection pressure is needed, the hydrogen supply requirement cannot be continuously met after the pressure of the hydrogen cylinder is reduced to the hydrogen injection pressure, and the direct hydrogen injection in the cylinder reduces the driving range compared with the air inlet channel injection under the same hydrogen storage condition.

Aiming at the problems of the hydrogen engine, the invention provides the hydrogen engine combining air inlet channel injection and in-cylinder direct injection, which adjusts the direct injection hydrogen and the air inlet channel injection hydrogen according to the opening degree signal of a throttle valve, and controls knocking by combining the in-cylinder water injection, thereby realizing good power response, high-efficiency power output and lower nitrogen oxide emission level of the hydrogen engine.

Disclosure of Invention

Aiming at the problems of a pure hydrogen engine, the invention provides a composite hydrogen injection engine and a control method thereof, which can realize the stable operation of the hydrogen engine under all working conditions without abnormal combustion phenomenon and simultaneously reduce the emission of nitrogen oxides.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a compound-injected hydrogen engine comprising: the air intake system is sequentially connected with an air flow sensor, a throttle valve and an air filter in series; the low-pressure hydrogen supply system is sequentially connected with a hydrogen cylinder, a low-pressure hydrogen reducing valve, a low-pressure hydrogen flow sensor and a gas inlet channel hydrogen injector in series; the high-pressure hydrogen supply system is sequentially connected with a hydrogen cylinder, a high-pressure hydrogen pressure reducing valve, a high-pressure hydrogen flow sensor and an in-cylinder direct injection hydrogen injector in series; the in-cylinder water spraying system is sequentially connected with a water tank, a high-pressure water pump, a water flow sensor and a water sprayer in series; the control system comprises an ECU, a spark plug, a crankshaft position sensor, a rotating speed sensor and a knock sensor.

The ECU is in signal interaction with an air flow sensor, a throttle valve, a low-pressure hydrogen pressure reducing valve, a low-pressure hydrogen flow sensor, an air inlet channel hydrogen injector, a high-pressure hydrogen pressure reducing valve, a high-pressure hydrogen flow sensor, an in-cylinder direct injection hydrogen injector, a high-pressure water pump, a water flow sensor, a water injector, a spark plug, a crankshaft position sensor, a rotating speed sensor and a knock sensor respectively;

the ECU is connected with the throttle valve and the air flow sensor through a lead, the air flow sensor monitors the air flow and feeds back signals to the ECU, and the opening of the throttle valve is controlled by sending out a throttle valve control signal so as to adjust the air inflow entering an engine cylinder;

the ECU is connected with a rotating speed sensor and a crankshaft position sensor through a lead so as to judge the rotating speed and the compression top dead center position of the engine and provide data reference for controlling the spraying time and the pulse width of the hydrogen and water;

the ECU is connected with the low-pressure hydrogen pressure reducing valve through a wire, and adjusts the low-pressure hydrogen pressure reducing valve according to a throttle control signal so as to control the injection pressure at the position of the hydrogen injector of the air inlet channel;

the ECU is connected with the low-pressure hydrogen flow sensor and the air inlet channel hydrogen injector through a lead, adjusts the injection time and the injection pulse width of the air inlet channel hydrogen injector according to a throttle control signal and a crankshaft position signal, and corrects the injection time and the injection pulse width through a feedback signal of the low-pressure hydrogen flow sensor to ensure the stability of an excess air coefficient;

the ECU is connected with the low-pressure hydrogen pressure reducing valve through a wire, and adjusts the low-pressure hydrogen pressure reducing valve according to a throttle control signal so as to control the injection pressure at the position of the hydrogen injector of the air inlet channel;

the ECU is connected with the high-pressure hydrogen pressure reducing valve and the in-cylinder direct injection hydrogen injector through a lead, adjusts the injection time and the injection pulse width of the in-cylinder direct injection hydrogen injector according to a throttle control signal and a crankshaft position signal, and corrects the injection time and the injection pulse width through a feedback signal of a high-pressure hydrogen flow sensor so as to ensure the stability of an excess air coefficient;

the ECU is connected with a knock sensor through a lead, and judges whether knocking occurs or not according to an output signal of the knock sensor;

the ECU is connected with the high-pressure water pump through a wire, and adjusts the output pressure of the high-pressure water pump according to the rotating speed of the engine and the opening degree signal of the throttle valve so as to adjust the injection pressure at the water injector;

the ECU is connected with the water flow sensor and the water injector through a lead, and the ECU adjusts the injection time and the injection pulse width of the water injector according to the knock signal and the crankshaft position signal;

the ECU is connected with a spark plug through a lead and adjusts the ignition time according to a throttle opening signal, a crankshaft position sensor signal, a rotating speed sensor signal and a knock sensor signal.

A control method of a compound injection hydrogen engine mainly comprises a fuel supply strategy and a combustion control strategy of the engine, and is characterized in that:

(1) fuel delivery strategy

a. Starting condition

The ECU receives a signal of a rotation speed sensor, when the rotation speed n is changed into n is not equal to 0, the starting working condition is adopted, in order to smoothly start, an air inlet channel injection strategy is adopted, the ECU controls a low-pressure hydrogen pressure reducing valve, an air inlet channel hydrogen injector and a throttle valve, the hydrogen supply quantity and the air quantity are regulated, feedback regulation is carried out according to the low-pressure hydrogen flow sensor and an air flow sensor, and the combustion excess air coefficient lambda is kept to be 1;

b. idling condition

The ECU receives signals of a rotating speed sensor, and when the rotating speed n is_{Idling speed}-50<n<n_{Idling speed}When the pressure is +50, the idling working condition is adopted, an air inlet channel hydrogen injection strategy is adopted, the ECU controls a low-pressure hydrogen pressure reducing valve, an air inlet channel hydrogen injector and a throttle valve, the hydrogen supply amount and the air amount are adjusted, feedback adjustment is carried out according to a low-pressure hydrogen flow sensor and an air flow sensor, and the combustion excess air coefficient lambda is kept to be 1.5;

c. low speed low load operating mode

The ECU (13) receives the signal of the rotation speed sensor (20) and detects the rotation speed n_{Idling speed}+50＜n＜2×n_{Idling speed}And the engine power demand P<30％×P_{Forehead (forehead)}When the low-speed low-load working condition is adopted, an air inlet channel hydrogen injection strategy is adopted, the ECU controls a low-pressure hydrogen pressure reducing valve and an air inlet channel hydrogen injector according to a throttle opening signal, the supply quantity of low-pressure hydrogen is adjusted, and feedback adjustment is carried out according to a low-pressure hydrogen flow sensor;

d. low speed medium and large load operating mode

The ECU receives signals of a rotating speed sensor, and when the rotating speed n is_{Idling speed}+50＜n＜2×n_{Idling speed}And the power demand P of the engine is more than or equal to 30% multiplied by P_{Forehead (forehead)}At the moment, the working condition is low-speed medium-large load, and an in-cylinder direct injection hydrogen strategy is adopted. The ECU controls a high-pressure hydrogen pressure reducing valve and a direct injection hydrogen injector in a cylinder according to a throttle opening signal, adjusts the supply amount of high-pressure hydrogen, and performs feedback adjustment according to a high-pressure hydrogen flow sensor (6);

e. medium and high speed working condition

The ECU receives signals of a rotating speed sensor, and when the rotating speed is 2 multiplied by n_{Idling speed}N is less than or equal to n, and at the moment, the hydrogen supply strategy combining air inlet channel injection and in-cylinder direct injection is adopted. ECU controls low-pressure hydrogen pressure reducing valve and air inlet according to throttle opening signalThe hydrogen injector is used for adjusting the supply quantity of the low-pressure hydrogen and carrying out feedback adjustment according to the low-pressure hydrogen flow sensor; the ECU controls a high-pressure hydrogen pressure reducing valve and a direct injection hydrogen injector in the cylinder according to the throttle opening signal, adjusts the supply amount of high-pressure hydrogen, and performs feedback adjustment according to a high-pressure hydrogen flow sensor; according to a throttle sensor signal of the engine, the proportion beta of the hydrogen injected from the air inlet channel to the hydrogen injected directly into the cylinder is adjusted, and the beta is regulated and controlled from 0 to 50% along with the increase of the throttle sensor signal;

wherein n is_{Idling speed}Calibrating the idling speed, P, for the engine_{Forehead (forehead)}Rated power for the engine;

β＝m_{direct injection in cylinder}/(m_{Air inlet channel}+m_{Direct injection in cylinder}) In the formula, m_{Direct injection in cylinder}、m_{Air inlet channel}The mass flow rates of direct-injection hydrogen in the cylinder and the mass flow rate of hydrogen injection in the air inlet channel are respectively;

excess air ratio of combustion process mixtureIn the formula (I), the compound is shown in the specification,wherein m is_air、Fresh air mass flow and total hydrogen mass flow,is the stoichiometric air-fuel ratio of hydrogen;

(2) combustion control strategy

The ECU receives a signal of the knock sensor, and if the knock sensor judges that no knock occurs, the ECU controls the ignition of the spark plug according to the torque requirement to keep the ignition time at the optimal ignition angle;

the ECU receives a signal of the knock sensor, and if the knock sensor judges that knocking occurs, the ECU controls the spark plug to delay the ignition time until the knocking does not occur;

if the ignition is delayed until the top dead center still can not eliminate the knocking, the ECU controls the high-pressure water pump and the water injector, controls the water injection amount by adjusting the injection pulse width, gradually increases from 0 until the knocking is eliminated, and maintains the current water injection amount to be unchanged under the working condition.

Compared with single air inlet channel injection or in-cylinder direct injection, the invention adopts the composite injection strategy of combining the air inlet channel and the in-cylinder direct injection, can flexibly adjust the injection strategy according to the working condition of the engine, can ensure good power response characteristic, and can avoid the problem of reduction of endurance mileage caused by only using high-pressure injection of in-cylinder direct injection. Meanwhile, the abnormal combustion problems of knocking, pre-ignition, tempering and the like caused by the improvement of the equivalence ratio under the high-load working condition are considered, and water is injected into the cylinder to eliminate the abnormal combustion and effectively reduce the emission of nitrogen oxides.

Drawings

The above and other features of the present invention will become more apparent by describing in detail embodiments thereof which are illustrated in the accompanying drawings.

FIG. 1 is a schematic diagram of the operation of a hybrid hydrogen injection engine and a control method thereof.

In the figure, the intake system (P1): an air flow sensor (9), a throttle valve (8), and an air cleaner (7); low-pressure hydrogen supply system (P2): a hydrogen cylinder (1), a low-pressure hydrogen reducing valve (3), a low-pressure hydrogen flow sensor (4) and a gas inlet channel hydrogen injector (11); high-pressure hydrogen supply system (P3): a hydrogen cylinder (2), a high-pressure hydrogen pressure reducing valve (5), a high-pressure hydrogen flow sensor (6) and a direct injection hydrogen injector (12); in-cylinder water injection system (P4): a water tank (19), a high-pressure water pump (18), a water flow sensor (17) and a water injector (16); control system (P5): the engine control device comprises an ECU (13), an ignition plug (15), a crankshaft position sensor (10), a rotating speed sensor (20) and a knock sensor (14).

Detailed Description

The present invention is further explained with reference to the following examples and drawings, but the scope of the present invention is not limited thereto.

A compound-injected hydrogen engine comprising: the air intake system (P1) is connected with an air flow sensor (9), a throttle valve (8) and an air filter (7) in series in sequence; the low-pressure hydrogen supply system (P2) is connected with a hydrogen cylinder (1), a low-pressure hydrogen pressure reducing valve (3), a low-pressure hydrogen flow sensor (4) and a gas inlet channel hydrogen injector (11) in series in sequence; the high-pressure hydrogen supply system (P3) is connected with a hydrogen cylinder (2), a high-pressure hydrogen pressure reducing valve (5), a high-pressure hydrogen flow sensor (6) and an in-cylinder direct injection hydrogen injector (12) in series in sequence; the in-cylinder water spraying system (P4) is sequentially connected with a water tank (19), a high-pressure water pump (18), a water flow sensor (17) and a water sprayer (16) in series; a control system (P5) includes an ECU (13), an ignition plug (15), a crank position sensor (10), a rotation speed sensor (20), and a knock sensor (14).

The ECU (13) is in signal interaction with an air flow sensor (9), a throttle valve (8), a low-pressure hydrogen pressure reducing valve (3), a low-pressure hydrogen flow sensor (4), an air inlet channel hydrogen injector (11), a high-pressure hydrogen pressure reducing valve (5), a high-pressure hydrogen flow sensor (6), an in-cylinder direct injection hydrogen injector (12), a high-pressure water pump (18), a water flow sensor (17), a water injector (16), a spark plug (15), a crankshaft position sensor (10), a rotating speed sensor (20) and a knock sensor (14) respectively;

the ECU (13) is connected with the throttle valve (8) and the air flow sensor (9) through leads, the opening of the throttle valve is controlled by sending out a throttle valve control signal, and the air flow sensor (9) monitors the air flow and feeds back the signal to the ECU (13) so as to adjust the air inflow entering the cylinder of the engine;

the ECU (13) is connected with a rotating speed sensor (20) and a crankshaft position sensor (10) through leads to judge the rotating speed and the compression top dead center position of the engine and provide data reference for controlling the spraying time and the pulse width of the hydrogen and water;

the ECU (13) is connected with the low-pressure hydrogen reducing valve (3) through a lead and adjusts the low-pressure hydrogen reducing valve (3) according to a throttle control signal so as to control the injection pressure at the position of the gas inlet channel hydrogen injector (11);

the ECU (13) is connected with the low-pressure hydrogen flow sensor (3) and the air inlet channel hydrogen injector (11) through a lead, the ECU (13) adjusts the injection time and the injection pulse width of the air inlet channel hydrogen injector (11) according to a throttle control signal and a crankshaft position signal, and the feedback signal of the low-pressure hydrogen flow sensor (4) is used for correcting so as to ensure the stability of an excess air coefficient;

the ECU (13) is connected with the low-pressure hydrogen reducing valve (3) through a lead and adjusts the low-pressure hydrogen reducing valve (3) according to a throttle control signal so as to control the injection pressure at the position of the gas inlet channel hydrogen injector (11);

the ECU (13) is connected with the high-pressure hydrogen pressure reducing valve (5) and the in-cylinder direct injection hydrogen injector (12) through a lead, the ECU (13) adjusts the injection time and the injection pulse width of the in-cylinder direct injection hydrogen injector (12) according to a throttle control signal and a crankshaft position signal, and the feedback signal of the high-pressure hydrogen flow sensor (6) is used for correcting so as to ensure the stability of an excess air coefficient;

the ECU (13) is connected with a knock sensor (14) through a lead, and judges whether knocking occurs or not according to an output signal of the knock sensor (14);

the ECU (13) is connected with the high-pressure water pump (18) through a lead, and adjusts the output pressure of the high-pressure water pump according to the rotating speed of the engine and the opening signal of the throttle valve so as to adjust the injection pressure at the water injector;

the ECU (13) is connected with a water flow sensor (17) and a water injector (16) through leads, and the ECU (13) adjusts the injection time and the injection pulse width of the water injector according to a knock signal and a crankshaft position signal;

the ECU (13) is connected to an ignition plug (15) by a wire, and adjusts the ignition timing based on a throttle opening signal, a crank position sensor signal, a rotational speed sensor signal, and a knock sensor signal.

A hydrogen engine with water sprayed in cylinder and its control method mainly includes the fuel supply strategy and combustion control strategy of engine.

(1) Fuel delivery strategy

a. Starting condition

The ECU (13) receives a signal of a rotating speed sensor (20), when the rotating speed n is equal to 0 and becomes n is not equal to 0, the starting working condition is adopted, for smooth starting, an air inlet channel injection strategy is adopted, the ECU (13) controls a low-pressure hydrogen reducing valve (3), an air inlet channel hydrogen injector (11) and a throttle valve (8), the hydrogen supply quantity and the air quantity are adjusted, correction is carried out according to feedback signals of a low-pressure hydrogen flow sensor (4) and an air flow sensor (9), and the excess combustion air coefficient lambda is kept to be 1;

b. idling condition

The ECU (13) receives the signal of the rotation speed sensor (20) and detects the rotation speed n_{Idling speed}-50<n<n_{Idling speed}At +50, in the idling working condition, an air inlet channel hydrogen injection strategy is adopted, an ECU (13) controls a low-pressure hydrogen pressure reducing valve (3), an air inlet channel hydrogen injector (11) and a throttle valve (8) to adjust the hydrogen supply amount and the air amount, feedback adjustment is carried out according to a low-pressure hydrogen flow sensor (4) and an air flow sensor (9), and the combustion excess air coefficient lambda is kept to be 1.5;

c. low speed low load operating mode

The ECU (13) receives the signal of the rotation speed sensor (20) and detects the rotation speed n_{Idling speed}+50＜n＜2×n_{Idling speed}And the engine power demand P<30％×P_{Forehead (forehead)}At the moment, under the low-speed and low-load working condition, an air inlet channel hydrogen injection strategy is adopted, and an ECU (13) controls a low-pressure hydrogen reducing valve (3) and an air inlet channel hydrogen injector (11) according to the opening degree signal of a throttle valve, adjusts the supply quantity of low-pressure hydrogen and performs feedback adjustment according to a low-pressure hydrogen flow sensor (4);

d. low speed medium and large load operating mode

The ECU (13) receives the signal of the rotation speed sensor (20) and detects the rotation speed n_{Idling speed}+50＜n＜2×n_{Idling speed}And the power demand P of the engine is more than or equal to 30% multiplied by P_{Forehead (forehead)}At the moment, the working condition is low-speed medium-large load, and an in-cylinder direct injection hydrogen strategy is adopted. The ECU (13) controls the high-pressure hydrogen pressure reducing valve (5) and the in-cylinder direct injection hydrogen injector (12) according to the throttle opening degree signal, adjusts the supply amount of high-pressure hydrogen, and corrects according to the feedback signal of the high-pressure hydrogen flow sensor (6) to ensure the stability of the excess air coefficient;

e. medium and high speed working condition

The ECU (13) receives the signal of the rotation speed sensor (20) and detects the rotation speed of 2 Xn_{Idling speed}N is less than or equal to n, and at the moment, the hydrogen supply strategy combining air inlet channel injection and in-cylinder direct injection is adopted. The ECU (13) controls the low-pressure hydrogen reducing valve (3) and the gas inlet channel hydrogen injector (11) according to the throttle opening degree signal, adjusts the low-pressure hydrogen supply amount and controls the low-pressure hydrogen supply amount according to the lowCorrecting a feedback signal of the hydrogen pressure flow sensor (4) to ensure the stability of an excess air coefficient; the ECU (13) controls the high-pressure hydrogen pressure reducing valve (5) and the in-cylinder direct injection hydrogen injector (12) according to the throttle opening degree signal, adjusts the supply amount of high-pressure hydrogen, and corrects according to the feedback signal of the high-pressure hydrogen flow sensor (6) to ensure the stability of the excess air coefficient; according to a throttle sensor signal of the engine, the proportion beta of the hydrogen injected from the air inlet channel to the hydrogen injected directly into the cylinder is adjusted, and the beta is regulated and controlled from 0 to 50% along with the increase of the throttle signal;

wherein n is_{Idling speed}Calibrating the idling speed, P, for the engine_{Forehead (forehead)}Rated power for the engine;

β＝m_{direct injection in cylinder}/(m_{Air inlet channel}+m_{Direct injection in cylinder}) In the formula, m_{Direct injection in cylinder}、m_{Air inlet channel}The mass flow rates of direct-injection hydrogen in the cylinder and the mass flow rate of hydrogen injection in the air inlet channel are respectively;

excess air ratio of combustion process mixtureIn the formula (I), the compound is shown in the specification,wherein m is_air、Fresh air mass flow and total hydrogen mass flow,is the stoichiometric air-fuel ratio of hydrogen;

(2) combustion control strategy

The ECU (13) receives a signal of the knock sensor (14), and if the knock sensor (14) judges that no knock occurs, the ECU controls the ignition of the spark plug according to a torque demand to keep the ignition time at the optimal ignition angle;

the ECU (13) receives a signal of the knock sensor (14), and if the knock sensor (14) judges that knocking occurs, the ECU (14) controls the spark plug (16) to delay the ignition time until the knocking does not occur;

if ignition is delayed until knocking is eliminated, the ECU (13) controls the high-pressure water pump (18) and the water injector (16), controls the water injection amount by adjusting the injection pulse width, and gradually increases from 0 until the knocking is eliminated, so that the current water injection amount is kept unchanged under the working condition;

nothing in this specification is said to apply to the prior art.