CN113586260B - A kind of compound injection hydrogen engine and control method - Google Patents

Abstract

The invention relates to a compound hydrogen injection engine and a control method, in particular to a compound injection hydrogen engine and a control method combining intake port injection and in-cylinder direct injection. The engine includes an intake system, a high-pressure hydrogen supply system, a low-pressure hydrogen supply system, an in-cylinder water injection system and an electronic control system. According to the engine power demand and working state, the ratio of direct injection hydrogen and intake port hydrogen injection is adjusted, and the valve opening is adjusted to control the intake air volume, thereby controlling the power output of the engine. The ECU judges the crankshaft position and speed through the crankshaft position sensor and the speed sensor, and judges the occurrence of knocking according to the signal of the knock sensor. Adjust the water pump pressure and the injection pulse width of the water injector according to the knock signal to control abnormal combustion problems such as pre-ignition, flashback and knock. The engine and the control method can realize the flexible adjustment characteristics of the engine, and can eliminate the knocking of the hydrogen engine, reduce the emission of nitrogen oxides, and improve the efficiency of the hydrogen engine.

Description

A kind of compound jet hydrogen engine and control method

technical field

A compound injection hydrogen engine and a control method, in particular to a spark ignition engine combining intake port hydrogen injection and in-cylinder hydrogen injection, and a control method, belonging to the field of internal combustion engines.

Background technique

In recent years, with the rapid expansion of car ownership, my country's transportation industry is facing increasing pressures of "carbon peaking" and "carbon neutrality", and the combustion of fossil fuels in automobile engines will also lead to the emission of various pollutants , resulting in increasingly prominent environmental problems, the development of alternative fuel technology is receiving extensive attention.

Hydrogen is a renewable fuel with a wide range of sources. It can be produced by electrolysis of water, which can play a regulating role of "shaving peaks and flat valleys". Hydrogen has excellent combustion characteristics, such as short quenching distance, fast combustion speed, low minimum ignition energy and wide flammability limit, etc., so hydrogen is suitable as a fuel for internal combustion engines.

The current hydrogen engine mainly uses the intake port to inject hydrogen, which is pre-mixed with air and then fed into the cylinder. However, at a high equivalence ratio, it faces abnormal combustion phenomena such as pre-ignition, flashback and knocking, which limits the performance of the hydrogen engine. practical application. And when operating at higher equivalence ratios, the nitrogen oxide emission levels of the hydrogen engine increased dramatically. The technology to control abnormal combustion mainly adopts the EGR (exhaust gas recirculation) strategy, but the EGR strategy will cause the intake air temperature to rise, reduce the cylinder volume efficiency, and lead to a decrease in power and efficiency. Previous researchers proposed the strategy of direct hydrogen injection in the cylinder to eliminate the flashback problem. Due to the high injection pressure required, the hydrogen cylinder pressure cannot continue to meet the hydrogen supply requirements after the hydrogen injection pressure is reduced. Under these conditions, the direct injection in the cylinder reduces the driving range compared with the port injection.

Aiming at the problems faced by the hydrogen engine, the present invention proposes a hydrogen engine combining port injection and in-cylinder direct injection. According to the throttle valve opening signal, the direct injection of hydrogen and the port injection of hydrogen are adjusted, and combined with the in-cylinder injection Water controls knocking to achieve good power response, efficient power output and low NOx emission levels of hydrogen engines.

SUMMARY OF THE INVENTION

In view of the problems existing in the pure hydrogen engine, the technical problem solved by the present invention is to propose a compound injection hydrogen engine and a control method, which can realize the stable operation of the hydrogen engine under all working conditions without abnormal combustion, and at the same time Reduce nitrogen oxide emissions.

The technical scheme adopted by the present invention to solve the technical problem is:

A compound jet hydrogen engine comprises: an air intake system, on which an air flow sensor, a throttle valve, and an air filter are sequentially connected in series; Flow sensor, intake port hydrogen injector; high-pressure hydrogen supply system, connected in series with hydrogen cylinder, high-pressure hydrogen pressure reducing valve, high-pressure hydrogen flow sensor, in-cylinder direct-injection hydrogen injector; in-cylinder water spray system, connected in sequence A water tank, a high-pressure water pump, a water flow sensor, and a water injector are connected in series; the control system includes an ECU, a spark plug, a crankshaft position sensor, a rotational speed sensor, and a knock sensor.

ECU is respectively connected with air flow sensor, throttle valve, low pressure hydrogen pressure reducing valve, low pressure hydrogen flow sensor, intake port hydrogen injector, high pressure hydrogen pressure reducing valve, high pressure hydrogen flow sensor, in-cylinder direct injection hydrogen injector, high pressure water pump, The water flow sensor, water injector, spark plug, crankshaft position sensor, rotational speed sensor and knock sensor have signal interaction;

The ECU is connected with the throttle valve and the air flow sensor through wires. The air flow sensor monitors the air flow and feeds back the signal to the ECU, and controls the opening of the throttle valve by sending out the throttle valve control signal to adjust the intake air volume entering the engine cylinder;

The ECU is connected with the speed sensor and the crankshaft position sensor through wires to judge the engine speed and the compression top dead center position, and provide data reference for controlling the injection timing and pulse width of hydrogen and water;

The ECU is connected with the low-pressure hydrogen pressure reducing valve through a wire, and adjusts the low-pressure hydrogen reducing valve according to the throttle control signal to control the injection pressure at the hydrogen injector in the intake port;

The ECU is connected with the low pressure hydrogen flow sensor and the intake port hydrogen injector through wires. The ECU adjusts the injection timing and injection pulse width of the intake port hydrogen injector according to the throttle control signal and the crankshaft position signal, and through the feedback of the low pressure hydrogen flow sensor The signal is corrected to ensure that the excess air coefficient is stable;

The ECU is connected with the low-pressure hydrogen pressure reducing valve through a wire, and adjusts the low-pressure hydrogen reducing valve according to the throttle control signal to control the injection pressure at the hydrogen injector in the intake port;

The ECU is connected with the high-pressure hydrogen pressure reducing valve and the in-cylinder direct-injection hydrogen injector through wires. The ECU adjusts the injection timing and injection pulse width of the in-cylinder direct-injection hydrogen injector according to the throttle valve control signal and the crankshaft position signal, and passes the high-pressure hydrogen flow rate. The feedback signal of the sensor is corrected to ensure the stability of the excess air coefficient;

The ECU is connected with the knock sensor through the wire, and judges whether the knock occurs according to the output signal of the knock sensor;

The ECU is connected with the high-pressure water pump through wires, and adjusts the output pressure of the high-pressure water pump according to the engine speed and the throttle opening signal to adjust the injection pressure at the water injector;

The ECU communicates with the water flow sensor and the water injector through the wire, and the ECU adjusts the injection timing and the injection pulse width of the water injector according to the knock signal and the crankshaft position signal;

The ECU is connected with the spark plug through wires, and adjusts the ignition timing according to the throttle valve opening signal, crankshaft position sensor signal, rotational speed sensor signal and knock sensor signal.

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

(1) Fuel supply strategy

a. Startup condition

The ECU accepts the signal from the speed sensor. When the speed n=0 becomes n≠0, it is the starting condition. In order to start smoothly, the inlet port injection strategy is adopted. The ECU controls the low-pressure hydrogen pressure reducing valve and the inlet port hydrogen injection. adjust the hydrogen supply and air volume, and perform feedback adjustment according to the low-pressure hydrogen flow sensor and the air flow sensor to keep the combustion excess air coefficient λ=1;

b. Idle condition

The ECU accepts the signal from the speed sensor. When the speed is nidle-50<n< _nidle +50, this is the _idle condition, and the intake port hydrogen injection strategy is adopted. The ECU controls the low-pressure hydrogen pressure reducing valve and the intake port hydrogen injection. adjust the hydrogen supply and air volume, and perform feedback adjustment according to the low-pressure hydrogen flow sensor and air flow sensor to keep the excess combustion air coefficient λ=1.5;

c. Low speed and low load conditions

The ECU (13) accepts the signal from the rotational speed sensor (20). When the rotational speed nidle+50<n<2× _nidle , and the _engine power requirement P<30%×P, it _is a low-speed and low-load condition, and the input Port hydrogen injection strategy, the ECU controls the low pressure hydrogen pressure reducing valve and the intake port hydrogen injector according to the throttle opening signal, adjusts the low pressure hydrogen supply amount, and performs feedback adjustment according to the low pressure hydrogen flow sensor;

d. Low speed, medium and large load conditions

The ECU accepts the signal from the speed sensor. When the speed n _{idle speed} +50 < n < 2 × n _{idle speed} , and the engine power demand is P ≥ 30% × P _amount , it is a low-speed, medium-heavy load condition, and the in-cylinder direct hydrogen injection strategy is adopted. . The ECU controls the high-pressure hydrogen pressure reducing valve and the in-cylinder direct-injection hydrogen injector according to the throttle valve opening signal, adjusts the high-pressure hydrogen supply amount, and performs feedback adjustment according to the high-pressure hydrogen flow sensor (6);

e. Medium and high speed conditions

The ECU accepts the signal from the rotational speed sensor. When the rotational speed is 2×n _idling ≤n, it is a medium and high-speed working condition, and a hydrogen supply strategy combining port injection and in-cylinder direct injection is adopted. The ECU controls the low-pressure hydrogen pressure reducing valve and the intake port hydrogen injector according to the throttle opening signal, adjusts the low-pressure hydrogen supply, and performs feedback adjustment according to the low-pressure hydrogen flow sensor; ECU controls the high-pressure hydrogen reducing valve according to the throttle opening signal and in-cylinder direct injection hydrogen injector to adjust the supply of high-pressure hydrogen, and perform feedback adjustment according to the high-pressure hydrogen flow sensor; As the throttle sensor signal increases, β is regulated from 0 to 50%;

Among them, nidle speed is the rated _idle speed of the engine, and P _is the rated power of the engine;

β=m in- _{cylinder direct injection} /(m _{intake ports} + m in- _{cylinder direct injection} ), in the formula, m in- _{cylinder direct injection} and m _{intake ports} are the mass flow of in-cylinder direct hydrogen injection and intake port hydrogen injection, respectively ;

式中，

其中m_air、

分别为新鲜空气质量流量和总氢气质量流量，

为氢气的化学计量空燃比；Combustion process mixture excess air coefficient

In the formula,

where m _air ,

are the fresh air mass flow and the total hydrogen mass flow, respectively,

is the stoichiometric air-fuel ratio of hydrogen;

(2) Combustion control strategy

The ECU receives the signal from the knock sensor. If the knock sensor judges that no knock occurs, the ECU controls the ignition of the spark plug according to the torque demand to keep the ignition timing at the optimum ignition angle;

The ECU receives the signal from the knock sensor. If the knock sensor determines that knocking occurs, the ECU controls the spark plug to delay the ignition timing until no knocking occurs;

If the knocking cannot be eliminated by delaying the ignition to the top dead center, the ECU controls the high-pressure water pump and the water injector, and controls the water injection amount by adjusting the injection pulse width, and gradually increases from 0 until the knocking is eliminated, and then maintains this condition. The current water injection volume is unchanged.

The advantage of the present invention is that, compared with the single port injection or the direct injection in the cylinder, the present invention adopts the composite injection strategy combining the intake port and the direct injection in the cylinder, and can flexibly adjust the injection strategy according to the engine operating conditions. It can not only ensure good dynamic response characteristics, but also avoid the problem of reduced cruising range caused by high-pressure injection only using direct injection in the cylinder. At the same time, the abnormal combustion problems such as knocking, pre-ignition and flashback caused by increasing the equivalence ratio under high load conditions are considered, and the use of in-cylinder water injection can eliminate abnormal combustion and effectively reduce nitrogen oxide emissions.

Description of drawings

The above and other features of the present invention will become more apparent from the detailed description of the embodiments shown in conjunction with the accompanying drawings.

FIG. 1 is a working schematic diagram of a compound injection hydrogen engine and a control method of the present invention.

In the figure, air intake system (P1): air flow sensor (9), throttle valve (8), air filter (7); low pressure hydrogen supply system (P2): first hydrogen cylinder (1), low pressure hydrogen Pressure valve (3), low pressure hydrogen flow sensor (4), inlet port hydrogen injector (11); high pressure hydrogen supply system (P3): second hydrogen cylinder (2), high pressure hydrogen pressure reducing valve (5), high pressure hydrogen Hydrogen flow sensor (6), in-cylinder direct injection hydrogen injector (12); in-cylinder water injection system (P4): water tank (19), high-pressure water pump (18), water flow sensor (17), water injector (16) ); control system (P5): ECU (13), spark plug (15), crankshaft position sensor (10), rotational speed sensor (20), knock sensor (14).

Detailed ways

The present invention is further explained below with reference to the embodiments and accompanying drawings, but this is not intended to limit the protection scope of the present application.

A compound injection hydrogen engine comprises: an air intake system (P1), on which an air flow sensor (9), a throttle valve (8), and an air filter (7) are sequentially connected in series; a low-pressure hydrogen supply system (P2), which is A first hydrogen cylinder (1), a low-pressure hydrogen pressure reducing valve (3), a low-pressure hydrogen flow sensor (4), an inlet port hydrogen injector (11) are connected in series on the upper part in sequence; a high-pressure hydrogen supply system (P3) is connected in sequence A second hydrogen cylinder (2), a high-pressure hydrogen pressure reducing valve (5), a high-pressure hydrogen flow sensor (6), an in-cylinder direct-injection hydrogen injector (12), and an in-cylinder water injection system (P4) are connected in series in series There are water tank (19), high pressure water pump (18), water flow sensor (17), water injector (16); control system (P5), including ECU (13), spark plug (15), crankshaft position sensor (10), Speed sensor (20), knock sensor (14).

The ECU (13) is respectively connected 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 intake port hydrogen injector (11), and a high pressure hydrogen pressure reducing valve. Valve (5), high pressure hydrogen flow sensor (6), in-cylinder direct injection hydrogen injector (12), high pressure water pump (18), water flow sensor (17), water injector (16), spark plug (15), crankshaft The position sensor (10), the rotational speed sensor (20), and the knock sensor (14) have signal interaction;

The ECU (13) is connected with the throttle valve (8) and the air flow sensor (9) through wires, and controls the opening of the throttle valve by sending out a throttle control signal. The air flow sensor (9) monitors the air flow and feeds back the signal to ECU (13) to adjust the amount of intake air entering the engine cylinder;

The ECU (13) is connected with the rotational speed sensor (20) and the crankshaft position sensor (10) through wires to judge the rotational speed of the engine and the position of the compression top dead center, and provide data reference for controlling the injection timing and pulse width of hydrogen and water;

The ECU (13) is connected with the low pressure hydrogen pressure reducing valve (3) through a wire, and adjusts the low pressure hydrogen pressure reducing valve (3) according to the throttle valve control signal to control the injection pressure at the intake port hydrogen injector (11);

The ECU (13) is connected with the low-pressure hydrogen flow sensor (3) and the intake port hydrogen injector (11) through wires, and the ECU (13) adjusts the intake port hydrogen injector (11) according to the throttle valve control signal and the crankshaft position signal. The injection time and injection pulse width are corrected by the feedback signal of the low pressure hydrogen flow sensor (4) to ensure the stability of the excess air coefficient;

The ECU (13) is connected with the low pressure hydrogen pressure reducing valve (3) through a wire, and adjusts the low pressure hydrogen pressure reducing valve (3) according to the throttle valve control signal to control the injection pressure at the intake port 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 wire, and the ECU (13) adjusts the in-cylinder direct-injection hydrogen injector (12) according to the throttle valve control signal and the crankshaft position signal. 12) the injection time and injection pulse width, and corrected by the feedback signal of the high-pressure hydrogen flow sensor (6) to ensure the stability of the excess air coefficient;

The ECU (13) is connected with the knock sensor (14) through a wire, and judges whether knocking occurs according to the output signal of the knock sensor (14);

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

The ECU (13) communicates with the water flow sensor (17) and the water injector (16) through the wire, and the ECU (13) adjusts the injection timing and the injection pulse width of the water injector according to the knock signal and the crankshaft position signal;

The ECU (13) is connected with the spark plug (15) through a wire, and adjusts the ignition timing according to the throttle valve opening signal, the crankshaft position sensor signal, the rotational speed sensor signal and the knock sensor signal.

An in-cylinder water-injected hydrogen engine and a control method mainly include a fuel supply strategy and a combustion control strategy of the engine.

(1) Fuel supply strategy

a. Startup condition

The ECU (13) accepts the signal from the rotational speed sensor (20). When the rotational speed n=0 becomes n≠0, this is the starting condition. In order to start smoothly, the port injection strategy is adopted, and the ECU (13) controls the low-pressure hydrogen gas. The pressure reducing valve (3), the intake port hydrogen injector (11) and the throttle valve (8) adjust the hydrogen supply amount and air amount, and carry out the operation according to the feedback signals of the low pressure hydrogen flow sensor (4) and the air flow sensor (9). Correction, keep the combustion excess air coefficient λ=1;

b. Idle condition

The ECU (13) accepts the signal from the rotational speed sensor (20). When the rotational speed is nidle-50<n< _nidle +50, this is the _idle condition, and the intake port hydrogen injection strategy is adopted, and the ECU (13) controls the low-pressure hydrogen The pressure reducing valve (3), the intake port hydrogen injector (11) and the throttle valve (8) adjust the hydrogen supply amount and air amount, and perform feedback adjustment according to the low pressure hydrogen flow sensor (4) and the air flow sensor (9). , keep the combustion excess air coefficient λ=1.5;

c. Low speed and low load conditions

The ECU (13) accepts the signal from the rotational speed sensor (20). When the rotational speed nidle+50<n<2× _nidle , and the _engine power requirement P<30%×P, it _is a low-speed and low-load condition, and the input In the port hydrogen injection strategy, the ECU (13) controls the low pressure hydrogen pressure reducing valve (3) and the intake port hydrogen injector (11) according to the throttle valve opening signal, adjusts the low pressure hydrogen supply amount, and adjusts the low pressure hydrogen supply amount according to the low pressure hydrogen flow sensor (4). ) for feedback adjustment;

d. Low speed, medium and large load conditions

The ECU (13) accepts the signal from the rotational speed sensor (20). When the rotational speed n _{idle speed} +50 < n < 2 × n _{idle speed} , and the engine power requirement P ≥ 30% × P _amount , at this time it is a low speed, medium and large load condition, and the use of In-cylinder direct injection hydrogen strategy. 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 signal, adjusts the supply amount of high-pressure hydrogen, and performs the process according to the feedback signal of the high-pressure hydrogen flow sensor (6). Correction to ensure that the excess air coefficient is stable;

e. Medium and high speed conditions

The ECU (13) receives the signal from the rotational speed sensor (20), and when the rotational speed is 2×n _idling ≤n, it is a medium-high-speed working condition, and a hydrogen supply strategy combining port injection and in-cylinder direct injection is adopted. The ECU (13) controls the low-pressure hydrogen pressure reducing valve (3) and the intake port hydrogen injector (11) according to the throttle opening signal, adjusts the low-pressure hydrogen supply amount, and makes corrections according to the feedback signal of the low-pressure hydrogen flow sensor (4). , to ensure the stability of the 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 signal, adjusts the high-pressure hydrogen supply amount, and adjusts the high-pressure hydrogen flow according to the high-pressure hydrogen flow. The feedback signal of the sensor (6) is corrected to ensure the stability of the excess air coefficient; according to the throttle valve sensor signal of the engine, the ratio β of hydrogen injection in the intake port and the direct injection of hydrogen in the cylinder is adjusted. With the increase of the throttle valve signal, β Adjust from 0 to 50%;

Among them, nidle speed is the rated _idle speed of the engine, and P _is the rated power of the engine;

β=m in- _{cylinder direct injection} /(m _{intake ports} + m in- _{cylinder direct injection} ), in the formula, m in- _{cylinder direct injection} and m _{intake ports} are the mass flow of in-cylinder direct hydrogen injection and intake port hydrogen injection, respectively ;

式中，

其中m_air、

分别为新鲜空气质量流量和总氢气质量流量，

为氢气的化学计量空燃比；Combustion process mixture excess air coefficient

In the formula,

where m _air ,

are the fresh air mass flow and the total hydrogen mass flow, respectively,

is the stoichiometric air-fuel ratio of hydrogen;

(2) Combustion control strategy

The ECU (13) receives the signal of the knock sensor (14), and if the knock sensor (14) determines that no knocking occurs, the ECU controls the ignition of the spark plug according to the torque demand to keep the ignition timing at the optimum ignition angle;

The ECU (13) receives the signal from the knock sensor (14), and if the knock sensor (14) determines that knocking occurs, the ECU (14) controls the spark plug (16) to delay the ignition timing until no knocking occurs;

If the knocking cannot be eliminated by delaying the ignition to the top dead center, the ECU (13) controls the high-pressure water pump (18) and the water injector (16), and controls the water injection amount by adjusting the injection pulse width, gradually increasing from 0 until the knocking If it is eliminated, the current water injection amount remains unchanged under this working condition;

What is not described in the present invention applies to the prior art.

Claims (2)

1. A compound injection hydrogen engine characterized by: the air intake system (P1) is sequentially connected with an air flow sensor (9), a throttle valve (8), an air filter (7), a low-pressure hydrogen supply system (P2), a first hydrogen bottle (1), a low-pressure hydrogen reducing valve (3), a low-pressure hydrogen flow sensor (4), an air inlet channel hydrogen injector (11), a high-pressure hydrogen supply system (P3), a second hydrogen bottle (2), a high-pressure hydrogen reducing valve (5), a high-pressure hydrogen flow sensor (6), a direct injection hydrogen injector (12), an in-cylinder water injection system (P4), a water tank (19), a high-pressure water pump (18), a water flow sensor (17), a water injector (16), a control system (P5), the air intake system comprises an ECU (13), a spark plug (15), a crankshaft position sensor (10), a rotating speed 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 reducing valve (3), a low-pressure hydrogen flow sensor (4), an air inlet channel hydrogen ejector (11), a high-pressure hydrogen reducing valve (5), a high-pressure hydrogen flow sensor (6), an in-cylinder direct injection hydrogen ejector (12), a high-pressure water pump (18), a water flow sensor (17), a water ejector (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 (4) 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 correction is carried out through a feedback signal of the low-pressure hydrogen flow sensor (4) so as to ensure the stability of an excess air coefficient;

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 knock 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 method of controlling a compound-injected hydrogen engine as claimed in claim 1, the method comprising a fueling strategy and a combustion control strategy, characterized by:

(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 a signal from the rotational speed sensor (20)When the rotational speed n is_{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 operation

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, under the working condition of low speed, medium and large load, the in-cylinder direct hydrogen injection 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 when the rotation speed is 2 Xn_{Idling speed}N is less than or equal to n, the medium-high speed working condition is adopted, and a 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 reducing valve (5) and the cylinder according to the throttle sensor signalAn internal direct injection hydrogen injector (12) for adjusting the supply amount of the high-pressure hydrogen and performing 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 the injection hydrogen in the air inlet channel are respectively;

excess air ratio of combustion process mixture

In 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 (15) 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.

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