JP4329748B2 - Internal combustion engine using hydrogen - Google Patents

Abstract

In an internal combustion engine using hydrocarbon fuel and hydrogen gas as fuels and including a fuel injection device that injects liquid fuel, a hydrogen-blended fuel in which hydrogen gas is contained in the form of minute bubbles in a liquid hydrocarbon fuel, that is supplied to the fuel injection device. The hydrogen-blended fuel is stored in a fuel tank. Hydrogen gas that has escaped from the hydrogen-blended fuel in the fuel tank is fed to a minute-bubble producing device, which forms the fuel gas into minute bubbles and mixes the minute bubbles back into the hydrogen-blended fuel.

Description

  The present invention relates to a hydrogen-based internal combustion engine that can use hydrocarbon-based liquid fuel and hydrogen gas as fuel.

  Conventionally, an internal combustion engine (hydrogen-use internal combustion engine) that uses hydrogen gas as a fuel together with liquid fuel such as gasoline is known. Hydrogen gas has characteristics that are excellent in combustibility compared with liquid fuel. For this reason, when the load is low, the lean burn region of the internal combustion engine can be expanded by adding hydrogen gas to the liquid fuel, and remarkable effects such as improvement of fuel consumption and reduction of NOx emission amount can be obtained. On the other hand, at high loads, knocking can be suppressed by adding hydrogen gas to the liquid fuel, and the output can be improved and the acceleration performance of the vehicle can be maintained.

One example of such a hydrogen-utilizing internal combustion engine is described in Patent Document 1. The internal combustion engine using hydrogen described in Patent Document 1 connects an injection valve that injects liquid fuel and a hydrogen tank via a hydrogen conduit so that liquid fuel and hydrogen gas can be injected simultaneously from one injection valve. Yes.
JP 2003-293809 A JP 2004-100501 A

  However, in the above-described conventional hydrogen-utilized internal combustion engine, it is necessary to separately provide two fuel supply systems, that is, a supply system that supplies hydrogen gas to the injection valve and a supply system that supplies liquid fuel to the injection valve. . For this reason, compared with an internal combustion engine that uses only liquid fuel, the system configuration becomes extremely complicated, leading to deterioration in mountability on a vehicle accompanying an increase in the number of parts and an increase in manufacturing cost.

  The present invention has been made to solve the above-described problems, and provides a hydrogen-based internal combustion engine that can use hydrogen gas as fuel in addition to liquid fuel without complicating the system. The purpose is to do.

In order to achieve the above object, a first invention provides a hydrogen-based internal combustion engine capable of using hydrocarbon liquid fuel and hydrogen gas as fuels.
A fuel injection device for injecting liquid fuel; and
Storage means for storing liquid hydrogen compounds;
Hydrogen generating means for generating hydrogen gas from the liquid hydrogen compound stored in the storage means;
Hydrogen mixing means for mixing the hydrogen gas generated by the hydrogen generation means with the liquid fuel supplied to the fuel injection device;
Determining means for determining the necessity of supplying hydrogen gas to the internal combustion engine;
Control means for operating the hydrogen generation means and the hydrogen mixing means when it is determined by the determination means that hydrogen gas needs to be supplied;
It is characterized by having.

According to a second invention, in the first invention,
The hydrogen mixing means includes means for generating hydrogen gas fine bubbles, and the hydrogen gas fine bubbles are mixed with the liquid fuel.

According to a third invention, in the first or second invention,
A hydrogen mixing amount determining means for determining a necessary hydrogen mixing amount when it is determined by the determining means that it is necessary to supply hydrogen gas;
The control means causes the hydrogen generation means to generate hydrogen gas in accordance with the hydrogen mixing amount determined by the hydrogen mixing amount determination means.

According to a fourth invention, in the third invention,
The hydrogen mixing amount determining means determines a necessary hydrogen mixing amount based on an operating state of the internal combustion engine.

According to a fifth invention, in the third invention,
The hydrogen mixing amount determining means determines a necessary hydrogen mixing amount based on the properties of the liquid fuel.

According to a sixth invention, in the third invention,
The hydrogen mixing amount determining means determines a necessary hydrogen mixing amount based on the atmospheric state.

According to a seventh invention, in the third invention,
The hydrogen mixing amount determining means determines a necessary hydrogen mixing amount based on a state of a catalyst disposed in an exhaust passage of the internal combustion engine.

Further, an eighth invention is a control device for a hybrid vehicle having the hydrogen-utilized internal combustion engine and the motor of the seventh invention, and capable of driving the vehicle by at least the motor.
When it is determined that it is necessary to supply hydrogen gas, the internal combustion engine is forcibly rotated by the motor in a state where combustion of the internal combustion engine is stopped, and the hydrogen generation means and the hydrogen mixing means are It is operated, and liquid fuel mixed with hydrogen gas is injected from the fuel injection device.

  According to the first invention, the hydrogen gas is stored in a liquid hydrogen compound state, and is generated from the liquid hydrogen compound when it is necessary to supply the hydrogen gas. Therefore, it is difficult to handle the hydrogen gas and the mounting efficiency is inferior. There is no need to store it in the gaseous state. Further, since the generated hydrogen gas is mixed with the liquid fuel and supplied to the fuel injection device, the range of handling the hydrogen gas in a gaseous state is limited to the period from the generation of the hydrogen gas to the mixing with the liquid fuel, Furthermore, hydrogen gas can be injected as a liquid integrally with the liquid fuel. Therefore, according to the first invention, a complicated system as in the case of supplying hydrogen gas and liquid fuel to the fuel injection device using separate fuel supply systems is not required, and the system is not complicated. In addition to liquid fuel, hydrogen gas can also be used as fuel.

  According to the second aspect of the present invention, hydrogen gas is made into fine bubbles and mixed with the liquid fuel, so that the hydrogen gas can be uniformly mixed with the liquid fuel, and the dissolution of the hydrogen gas into the liquid fuel is promoted. can do. Thereby, there is little possibility that the hydrogen gas is separated from the liquid fuel during the period from the mixing of the hydrogen gas to the fuel injection, and a countermeasure for the separated hydrogen gas becomes unnecessary, and the system configuration can be further simplified.

  According to the third aspect, since a necessary amount of hydrogen gas is generated when it is necessary to supply hydrogen gas, the necessary amount of hydrogen gas can be mixed with the liquid fuel without excess or deficiency. This eliminates the need for a buffer tank for adjusting the deviation between the amount of hydrogen gas generated and the amount of supply, and the system configuration can be further simplified.

  According to the fourth invention, hydrogen can be mixed with the liquid fuel at a mixing ratio according to the operating state of the internal combustion engine.

  According to the fifth aspect, hydrogen can be mixed into the liquid fuel at a mixing ratio according to the properties of the liquid fuel.

  According to the sixth aspect of the invention, hydrogen can be mixed with the liquid fuel at a mixing ratio corresponding to the atmospheric state.

  According to the seventh aspect, hydrogen can be mixed into the liquid fuel at a mixing ratio corresponding to the state of the catalyst.

  According to the eighth invention, when it is determined that it is necessary to supply hydrogen gas for catalyst reduction or warm-up, the hydrogen gas is mixed by the pump action when the motor is forcibly rotated by the motor. The liquid fuel thus made can be sent to the exhaust passage, and the reduction process and warm-up process of the catalyst can be performed efficiently. According to the eighth aspect of the invention, since the motor can travel even when the combustion of the internal combustion engine is stopped, it is possible to perform catalyst reduction processing or warm-up processing when necessary.

Embodiment 1 FIG.
Hereinafter, the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a diagram showing a system configuration of a hydrogen-utilized internal combustion engine (hereinafter simply referred to as an engine) as Embodiment 1 of the present invention. The engine of the present embodiment has an engine body 2 composed of a plurality of cylinders (only one cylinder is shown in FIG. 1). The engine body 2 has a piston 8 for each cylinder, and a combustion chamber 10 that repeats expansion and contraction by the vertical movement of the piston 8 is formed inside each cylinder. An intake passage 4 for supplying air to the combustion chamber 10 of each cylinder and an exhaust passage 6 for discharging combustion gas from the combustion chamber 10 are connected to the engine body 2. A catalyst (for example, NOx catalyst) 20 for purifying combustion gas is disposed in the exhaust passage 6.

  In the engine body 2, an intake valve 12 for controlling the communication state is provided at the connection portion between the intake passage 4 and the combustion chamber 10, and the communication state is provided at the connection portion between the exhaust passage 6 and the combustion chamber 10. An exhaust valve 14 to be controlled is provided. The combustion chamber 10 is provided with an in-cylinder injector 18 that directly injects fuel into the combustion chamber 10 and an ignition plug 16 that ignites the mixed gas therein.

  The in-cylinder injector 18 is connected to the fuel tank 30 by a fuel supply line 36. The fuel tank 30 stores gasoline, which is a hydrocarbon-based liquid fuel. The liquid fuel in the fuel tank 30 is sucked up by a fuel pump (high pressure pump) 32 disposed in the fuel supply line 36 and compressed to a predetermined pressure higher than the combustion gas pressure in the combustion chamber 10 before the in-cylinder injector 18. Supplied to. The fuel pump 32 may be a mechanical pump driven by the engine body 2 or an electric pump driven by a motor. The fuel tank 30 is provided with a fuel property sensor 54 that outputs a signal corresponding to the property (fuel property) of the liquid fuel in the fuel tank 30 such as the degree of heavyness, the octane number, and the degree of alcohol addition.

  A microbubble generator 52 for mixing hydrogen gas, which is the other fuel, with the liquid fuel is disposed downstream of the fuel pump 32 in the fuel supply line 36. The microbubble generator 52 converts hydrogen gas into fine bubbles (referred to as microbubbles) having a diameter of several tens of μm or less and mixes them with the liquid fuel in the fuel supply line 36. The method for generating microbubbles by the microbubble generator 52 is not limited as long as hydrogen gas can be converted into microbubbles in the liquid fuel. The microbubble generation method listed below is an example of a method that can be employed in the microbubble generator 52 of the present embodiment.

  First, a first example of a microbubble generation method is a method in which hydrogen gas is blown into a vigorous flow of liquid fuel, and the hydrogen gas is pulverized by a strong shearing force generated there.

  The second example of the microbubble generation method is a method of generating cavitation by increasing the flow rate of the liquid fuel from a state in which hydrogen gas is pressurized and dissolved in the liquid fuel more.

  And the 3rd example of the generation method of a microbubble is a method which vibrates and splits the bubble of hydrogen gas in liquid fuel by giving an ultrasonic wave.

  By making hydrogen gas into microbubbles by the microbubble generator 52 and mixing it with liquid fuel, the hydrogen gas can be uniformly mixed in the liquid fuel, and the dissolution of hydrogen gas into the liquid fuel can be promoted. Can do. In addition, even if hydrogen gas exceeding the saturated hydrogen amount is supplied by making the hydrogen gas into microbubbles, the liquid gas can be contained in the liquid fuel in a microbubble state without being separated from the liquid fuel as long as it is a certain amount. Can be present uniformly. Therefore, there is little possibility that the hydrogen gas once mixed is separated from the liquid fuel before the fuel injection, and the hydrogen gas is substantially integrated with the liquid fuel from the microbubble generator 52 to the in-cylinder injector 18. It becomes possible to handle in a state.

  The hydrogen gas mixed with the liquid fuel by the microbubble generator 52 is supplied from the hydrogen generator 50 through the hydrogen gas supply line 46. The hydrogen generator 50 is an apparatus that can immediately generate hydrogen gas from a liquid hydrogen compound. As the liquid hydrogen compound, water, alcohol, gasoline, light oil or the like can be used. In this embodiment, water is used as the liquid hydrogen compound. As a method for generating hydrogen gas by the hydrogen generator 50, a method exemplified below can be adopted.

  First, a first example of a hydrogen generation method is a method of electrolyzing water by applying a counter electromotive force to a fuel cell.

  A second example of the hydrogen generation method is a method of decomposing a liquid hydrogen compound with low-temperature plasma. Specifically, hydrogen gas can be generated by performing direct current pulse discharge on the liquid hydrogen compound.

  A third example of the hydrogen generation method is a method of reducing water with a highly active metal. For example, by rubbing aluminum or an aluminum alloy in pure water, the corrosion reaction of water against the metal can be accelerated, water molecules can be decomposed, and pure hydrogen gas can be generated. Pure hydrogen gas can also be generated by supplying water to the powder of magnesium hydride or magnesium hydride alloy. Furthermore, pure hydrogen gas can be generated along with oxidation of metallic iron by reacting water vapor with metallic iron obtained by reducing iron oxide.

  Any of the above methods can immediately generate hydrogen gas from a liquid hydrogen compound such as water as needed. In particular, according to the method of the third example, only pure hydrogen gas can be generated. In addition, since any of the above methods can generate hydrogen gas at a relatively low temperature or room temperature, more hydrogen gas can be dissolved in the liquid fuel when the microbubble generator 52 mixes with the liquid fuel. There is also an advantage of being able to.

  By generating the hydrogen gas with the hydrogen generator 50, the hydrogen gas can be stored in a liquid state. Thereby, compared with the case where hydrogen gas is stored in a gas state in a pressure tank or the like, not only the handling is facilitated, but also high mounting efficiency can be realized. In the present embodiment, water used for generating hydrogen gas in the hydrogen generator 50 is supplied from the water tank 40 via the water supply line 44. The water supply line 44 is provided with a water pump 42 for sucking water from the water tank 40 and supplying it to the hydrogen generator 50.

  According to the system configuration as described above, the range in which hydrogen gas needs to be handled in a gaseous state is limited to the hydrogen gas supply line 46 from the hydrogen generator 50 to the microbubble generator 52. Thereby, compared with the case where hydrogen gas is handled in a gaseous state between the storage tank and fuel injection as in the prior art, measures against leakage of hydrogen gas and the like are simplified. Moreover, since the hydrogenated fuel obtained by mixing hydrogen gas with the liquid fuel supplied to the in-cylinder injector 18 is substantially liquid, a conventional in-cylinder injector for liquid fuel can be used as it is.

  The engine of this embodiment includes an ECU (Electronic Control Unit) 60 as its control device. Connected to the output side of the ECU 60 are various devices such as the ignition plug 16, the in-cylinder injector 18, the fuel pump 32, the water pump 42, the microbubble generator 52, and the hydrogen generator 50. On the input side of the ECU 60, in addition to the fuel property sensor 54 described above, information on the operating state of the engine body 2 (accelerator opening, vehicle speed, engine speed, air-fuel ratio, water temperature, knock signal, etc.) is acquired. Various sensors, such as the apparatus 62 and the atmospheric condition measuring apparatus 64 which acquires the information (temperature, humidity, atmospheric pressure, etc.) regarding the atmospheric condition, are connected. The ECU 60 controls each device according to a predetermined control program based on the output of each sensor.

  In the engine of this embodiment, the addition of hydrogen gas to liquid fuel is used to suppress knocking during high-load operation. FIG. 2 is a flowchart showing a routine for hydrogenation control executed by the ECU 60 in the present embodiment. The routine shown in FIG. 2 is periodically executed for each predetermined crank angle.

  In the first step S100 of the routine shown in FIG. 2, the magnitude (knock level) of knocking occurring in the engine body 2 is measured by the operating state measuring device 62. In the next step S102, a knock level when no hydrogen is added is obtained from the measured knock level, and success or failure of the hydrogenation execution condition is determined based on the knock level when no hydrogen is added. When the hydrogen addition execution condition is satisfied, the hydrogen gas is added to the liquid fuel by the processing from step S104 to step S110.

  In step S104, the required hydrogen addition ratio corresponding to the knock level and other operating states of the engine body 2, for example, the accelerator opening, the engine speed, the water temperature, the air-fuel ratio, etc., is obtained from the map stored in advance. . The hydrogen addition ratio can be defined, for example, as the ratio of the calorific value of hydrogen gas to the total calorific value of the entire fuel including liquid fuel and hydrogen gas. In the map, the required hydrogen addition ratio is set larger as the knock level without hydrogen addition is larger.

  In the next step S106, a required hydrogen generation amount (required hydrogen gas generation amount) corresponding to the required hydrogen addition ratio is obtained. Specifically, the required load of the engine body 2 is determined from the accelerator opening, the engine speed, and the like, and the load (hydrogen load) shared by the hydrogen gas is determined from the required load and the required hydrogen addition ratio. Then, based on the amount of heat generated per unit amount of hydrogen gas, the amount of hydrogen gas corresponding to the hydrogen load is calculated as the required hydrogen generation amount.

  In the next step S108, water corresponding to the required hydrogen generation amount is supplied from the water tank 40 to the hydrogen generator 50 by the operation of the water pump 42. Then, the hydrogen generation process is executed by the operation of the hydrogen generation device 50 to generate the required hydrogen generation amount of hydrogen gas. The generated hydrogen gas is supplied from the hydrogen generator 50 to the microbubble generator 52.

  In the next step S110, hydrogen gas is microbubbled by the microbubble generator 52, and the microbubbled hydrogen gas is mixed with the liquid fuel. The liquid fuel mixed with hydrogen gas is supplied from the microbubble generator 52 to the in-cylinder injector 18 and directly injected from the in-cylinder injector 18 into the combustion chamber 10.

  By injecting fuel containing hydrogen gas having excellent combustibility, knocking at high load is suppressed, and the knock level measured in step S100 is reduced. When the hydrogen addition execution condition is not satisfied in the determination in step S102, the hydrogen generation process in the hydrogen generator 50 is stopped (step S112), and then the microbubble generation process by the microbubble generator 52 is also stopped ( Step S114).

  According to the above hydrogenation control routine, when hydrogen gas is required to suppress knocking, hydrogen gas is immediately generated from water by the hydrogen generator 50, and the generated hydrogen gas is microbubbled. Mixed with liquid fuel. Thereby, knocking at the time of high load operation can be quickly suppressed, and highly efficient operation by advancement of ignition timing or the like becomes possible.

  Further, as described above, by generating hydrogen gas from water as necessary, it is not necessary to store the hydrogen gas in a gas state that is difficult to handle and inferior in mounting efficiency. Moreover, only the required amount of hydrogen gas is generated, and all the required amount of generated hydrogen gas is microbubbled and mixed with the liquid fuel, so that the deviation between the generated amount of hydrogen gas and the supply amount is adjusted. There is no need to provide a buffer tank.

  In the present embodiment, the “determining means” according to the first aspect of the present invention is realized by the processing of steps S100 and S102 being executed by the ECU 60. Further, the “control means” according to the first aspect of the present invention is realized by the ECU 60 executing the processes of steps S108 and S110 or S112 and S114. Further, the processing of steps S104 and S106 is executed by the ECU 60, thereby realizing the “hydrogen mixture amount determining means” according to the third invention.

Embodiment 2.
Hereinafter, the second embodiment of the present invention will be described with reference to FIG.

  The engine of the present embodiment can be realized by causing the ECU 60 to execute the routine of FIG. 3 instead of the routine of FIG. 2 in the system configuration according to the first embodiment. In the engine of this embodiment, the addition of hydrogen gas to the liquid fuel is used to suppress combustion fluctuations during lean burn operation. FIG. 3 is a flowchart showing a routine for hydrogenation control executed by the ECU 60 in the present embodiment. The routine shown in FIG. 3 is periodically executed for each predetermined crank angle.

  In the first step S200 of the routine shown in FIG. 3, the magnitude of combustion fluctuation (combustion fluctuation level) generated in the engine body 2 is measured by the operating state measuring device 62. Specifically, the combustion fluctuation level can be measured from fluctuations in engine speed and in-cylinder pressure. In the next step S202, the combustion fluctuation level when no hydrogen is added is obtained from the measured combustion fluctuation level, and the success or failure of the hydrogen addition execution condition is determined based on the combustion fluctuation level when no hydrogen is added. When the hydrogen addition execution condition is satisfied, the hydrogen gas is added to the liquid fuel by the processes in steps S204 to S210.

  In step S204, the required hydrogen addition ratio corresponding to the combustion fluctuation level and the other operating state of the engine body 2, for example, the accelerator opening, the engine speed, the water temperature, the air-fuel ratio, etc. is obtained from the map stored in advance. It is done. In the map, the required hydrogen addition ratio is set larger as the combustion fluctuation level without hydrogen addition is larger, and as the engine load obtained from the accelerator opening and the engine speed is lower. In the next step S206, a required hydrogen generation amount corresponding to the required hydrogen addition ratio is obtained.

  In the next step S208, a hydrogen generation process corresponding to the required hydrogen generation amount is executed by the operation of the water pump 42 and the hydrogen generator 50. The hydrogen gas generated by the hydrogen generator 50 is microbubbled by the microbubble generator 52 and mixed with the liquid fuel (step S210). The liquid fuel mixed with hydrogen gas is supplied from the microbubble generator 52 to the in-cylinder injector 18 and directly injected from the in-cylinder injector 18 into the combustion chamber 10.

  By injecting the fuel containing hydrogen gas having excellent combustibility, the combustion fluctuation at the time of low load is suppressed, and the combustion fluctuation level measured in step S200 becomes small. When the hydrogen addition execution condition is not satisfied in the determination of step S202, the hydrogen generation process in the hydrogen generator 50 is stopped (step S212), and then the microbubble generation process by the microbubble generator 52 is also stopped ( Step S214).

  According to the hydrogen addition control routine described above, when hydrogen gas is required to suppress combustion fluctuations, hydrogen gas is immediately generated from water by the hydrogen generator 50, and the generated hydrogen gas is converted into microbubbles. And mixed with liquid fuel. Thereby, the combustion fluctuation | variation at the time of lean burn operation can be suppressed rapidly, and a lean burn area | region can be expanded.

  In the present embodiment, the “determination means” according to the first aspect of the present invention is realized by the processing of steps S200 and S202 being executed by the ECU 60. Further, the “control means” according to the first aspect of the present invention is realized by the ECU 60 executing the processes of steps S208 and S210 or S212 and S214. Further, the processing of steps S204 and S206 is executed by the ECU 60, thereby realizing the “hydrogen mixture amount determining means” according to the third aspect of the invention.

Embodiment 3.
The third embodiment of the present invention will be described below with reference to FIG.

  The engine of the present embodiment can be realized by causing the ECU 60 to execute the routine of FIG. 4 instead of the routine of FIG. 2 in the system configuration according to the first embodiment. The engine of this embodiment uses the addition of hydrogen gas to the liquid fuel to correct the fuel properties. When the fuel properties of the liquid fuel change, the operation performance (misfire limit, knock limit, etc.) of the engine body 2 changes accordingly. In this embodiment, by correcting the fuel properties by adding hydrogen gas, a constant engine performance is always obtained. FIG. 4 is a flowchart showing a routine for hydrogenation control executed by the ECU 60 in the present embodiment. The routine shown in FIG. 4 is periodically executed for each predetermined crank angle.

  In the first step S300 of the routine shown in FIG. 4, the fuel properties (heavyness, octane number, degree of alcohol addition, etc.) of the liquid fuel stored in the fuel tank 30 are estimated from the signal of the fuel property sensor 54. The fuel property can also be estimated from the fluctuation state of the engine speed and the in-cylinder pressure. In the next step S302, it is determined whether or not the estimated fuel property is a fuel property that requires hydrogenation. Examples of fuel properties that require hydrogenation include heavy fuel, low-octane fuel, and fuel with a high degree of alcohol addition. Then, when it is estimated that the fuel property requires hydrogenation, hydrogen gas is added to the liquid fuel by the processing in steps S304 to S310.

  In step S304, the required hydrogen addition ratio corresponding to the fuel properties and the operating state of the engine body 2 is obtained from the map stored in advance. In the map, the required hydrogen addition ratio is set larger as the heavier, the lower octane number, and the higher the degree of alcohol addition. In the next step S306, a required hydrogen generation amount corresponding to the required hydrogen addition ratio is obtained.

  In the next step S308, the hydrogen generation process corresponding to the required hydrogen generation amount is executed by the operation of the water pump 42 and the hydrogen generator 50. The hydrogen gas generated by the hydrogen generator 50 is microbubbled by the microbubble generator 52 and mixed with the liquid fuel (step S310). The liquid fuel mixed with hydrogen gas is supplied from the microbubble generator 52 to the in-cylinder injector 18 and directly injected from the in-cylinder injector 18 into the combustion chamber 10.

  When the property of the liquid fuel in the fuel tank 30 changes due to refueling or the like, it may be determined in step S302 that it is not necessary to add hydrogen. In that case, the hydrogen generation process in the hydrogen generator 50 is stopped (step S312), and then the microbubble generation process by the microbubble generator 52 is also stopped (step S314).

  According to the above hydrogenation control routine, when the property of the liquid fuel is a fuel property requiring hydrogenation, hydrogen gas is immediately generated from water by the hydrogen generator 50, and the generated hydrogen gas is microbubbled. And mixed with liquid fuel. Thus, the difference in fuel properties is corrected by the degree of hydrogen addition, and constant engine performance can always be maintained regardless of the fuel properties.

  In the present embodiment, the “determination means” according to the first aspect of the present invention is realized by the processing of steps S300 and S302 being executed by the ECU 60. Further, the “control means” according to the first aspect of the present invention is realized by the ECU 60 executing the processes of steps S308 and S310 or S312 and S314. Further, the processing of steps S304 and S306 is executed by the ECU 60, thereby realizing the “hydrogen mixture amount determining means” according to the third aspect of the invention.

Embodiment 4.
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG.

  The engine of the present embodiment can be realized by causing the ECU 60 to execute the routine of FIG. 5 instead of the routine of FIG. 2 in the system configuration according to the first embodiment. In the engine of the present embodiment, hydrogen gas is added to the liquid fuel in order to correct the influence of atmospheric conditions on the operating performance (misfire limit, knock limit, etc.) of the engine body 2. FIG. 5 is a flowchart showing a routine for hydrogenation control executed by the ECU 60 in the present embodiment. The routine shown in FIG. 5 is periodically executed for each predetermined crank angle.

  In the first step S400 of the routine shown in FIG. 5, the current atmospheric state (temperature, humidity, atmospheric pressure, etc.) is measured by the atmospheric state measuring device 64. In the next step S402, it is determined whether or not the measured atmospheric condition is an atmospheric condition requiring hydrogenation. For example, knocking is more likely to occur at higher temperatures, higher pressures, and lower humidity, and depending on atmospheric conditions, hydrogenation is required to suppress knocking. On the other hand, misfires are more likely to occur at lower temperatures and lower pressures, and depending on atmospheric conditions, hydrogen addition is required to prevent misfires. In the case of an atmospheric condition that requires hydrogen addition, hydrogen gas is added to the liquid fuel by the processing in steps S404 to S410.

  In step S404, a required hydrogen addition ratio corresponding to the atmospheric state and the operating state of the engine body 2 is obtained from a map stored in advance. In the map, when the engine load obtained from the accelerator opening and the engine speed is high, the required hydrogen addition ratio is set larger as the temperature is higher, the pressure is higher, and the humidity is lower. When the engine load is low, the required hydrogen addition ratio is set larger as the temperature is lower and the pressure is lower. In the next step S406, a required hydrogen generation amount corresponding to the required hydrogen addition ratio is obtained.

  In the next step S408, the hydrogen generation process corresponding to the required hydrogen generation amount is executed by the operation of the water pump 42 and the hydrogen generator 50. The hydrogen gas generated by the hydrogen generator 50 is microbubbled by the microbubble generator 52 and mixed with the liquid fuel (step S410). The liquid fuel mixed with hydrogen gas is supplied from the microbubble generator 52 to the in-cylinder injector 18 and directly injected from the in-cylinder injector 18 into the combustion chamber 10.

  When the atmospheric state changes due to a change in weather or a change in the traveling altitude of the vehicle, it may be determined in step S402 that it is not necessary to add hydrogen. In that case, the hydrogen generation process in the hydrogen generator 50 is stopped (step S412), and then the microbubble generation process by the microbubble generator 52 is also stopped (step S414).

  According to the above hydrogenation control routine, when the current atmospheric state is an atmospheric state that requires hydrogenation, hydrogen gas is immediately generated from water by the hydrogen generator 50, and the generated hydrogen gas is microbubbled. And mixed with liquid fuel. Thereby, knocking at the time of high load operation and misfire at the time of low load operation due to the influence of temperature, humidity, atmospheric pressure, etc. are suppressed, and constant engine performance can always be maintained regardless of atmospheric conditions.

  In the present embodiment, the “determination means” according to the first aspect of the present invention is realized by the ECU 60 executing the processes of steps S400 and S402. Further, the “control means” according to the first aspect of the present invention is realized by the ECU 60 executing the processes of steps S408 and S410 or S412 and S414. Further, the processing of steps S404 and S406 is executed by the ECU 60, thereby realizing the “hydrogen mixture amount determining means” according to the third aspect of the invention.

Embodiment 5.
The fifth embodiment of the present invention will be described below with reference to FIG.

  The engine of the present embodiment can be realized by causing the ECU 60 to execute the routine of FIG. 6 instead of the routine of FIG. 2 in the system configuration according to the first embodiment. The engine of this embodiment adds hydrogen gas to the liquid fuel for the reduction process or warm-up process of the catalyst 20. FIG. 6 is a flowchart showing a routine for hydrogenation control executed by the ECU 60 in the present embodiment. The routine shown in FIG. 6 is periodically executed for each predetermined crank angle.

  In the first step S500 of the routine shown in FIG. 6, the operating state measuring device 62 measures the state of the catalyst 20, specifically, the NOx occlusion amount of the catalyst 20 and the temperature of the catalyst 20. The NOx occlusion amount of the catalyst 20 can be indirectly measured by the lean burn operation time from the previous reduction process. Further, the temperature of the catalyst 20 can be measured directly by a temperature sensor or indirectly from the temperature of the exhaust gas.

  In the next step S502, the presence or absence of a request for catalyst treatment is determined from the state of the catalyst 20 measured in step S500. For example, when the NOx occlusion amount of the catalyst 20 is close to the limit, it is determined that the reduction treatment of the catalyst 20 is necessary. Further, when the temperature of the catalyst 20 is lower than an appropriate temperature at which the purification performance is maximized, it is determined that the catalyst 20 needs to be warmed up. In any case, as a treatment method, hydrogen gas may be added to the liquid fuel and supplied to the catalyst 20. When hydrogen gas is added for the reduction treatment, the hydrogen gas can be made to act on the catalyst 20 as a reducing agent to efficiently restore the storage capacity of the catalyst 20. When hydrogen gas is added for the warm-up process, the hydrogen gas is reacted with oxygen on the catalyst 20, and the catalyst 20 can be efficiently warmed by the reaction heat at that time. Therefore, when there is any catalyst processing request, hydrogen gas is added to the liquid fuel by the processing from step S504 to step S510.

  In step S504, the required hydrogen addition ratio corresponding to the content of the catalyst processing request (reduction processing request or warm-up processing request) and the operating state of the engine body 2 is obtained from a map stored in advance. In the next step S506, a required hydrogen generation amount corresponding to the required hydrogen addition ratio is obtained.

  In the next step S508, the hydrogen generation process corresponding to the required hydrogen generation amount is executed by the operation of the water pump 42 and the hydrogen generator 50. The hydrogen gas generated by the hydrogen generator 50 is microbubbled by the microbubble generator 52 and mixed with the liquid fuel (step S510). The liquid fuel mixed with hydrogen gas is supplied from the microbubble generator 52 to the in-cylinder injector 18 and directly injected from the in-cylinder injector 18 into the combustion chamber 10. As a method of fuel injection at that time, a two-stage injection of a main injection injected in an intake stroke or a compression stroke and a secondary injection injected in an expansion stroke or an exhaust stroke is adopted. The hydrogen gas in the fuel injected by the sub-injection flows as it is to the catalyst 20 without being burned, and is used for the reduction process or warm-up process of the catalyst 20.

  When the reduction process or warm-up process of the catalyst 20 is completed, the request for the catalyst process is withdrawn in the determination of step S502. In that case, the hydrogen generation process in the hydrogen generator 50 is stopped (step S512), and then the microbubble generation process by the microbubble generator 52 is also stopped (step S514).

  According to the above hydrogenation control routine, when the reduction process or warm-up process of the catalyst 20 is required, hydrogen gas is immediately generated from water by the hydrogen generator 50, and the generated hydrogen gas is microbubbled. And mixed with liquid fuel. Thereby, when the reduction process is requested | required, the NOx occlusion capability of the catalyst 20 can be recovered rapidly, and when the warm-up process is requested | required, the temperature of the catalyst 20 is made into appropriate temperature. Can be warmed up quickly.

  In the present embodiment, the “determination means” according to the first aspect of the present invention is realized by the processing of steps S500 and S502 being executed by the ECU 60. Further, the “control means” according to the first aspect of the present invention is realized by the ECU 50 executing the processes of steps S508 and S510, or S512 and S514. Further, the processing of steps S504 and S506 is executed by the ECU 60, thereby realizing the “hydrogen mixture amount determining means” according to the third aspect of the invention.

Embodiment 6 FIG.
Hereinafter, Embodiment 6 of the present invention will be described with reference to FIG. 7 and FIG.

  FIG. 7 is a diagram showing the configuration of a hybrid vehicle drive system to which the hydrogen-utilized internal combustion engine of the present invention is applied. The hybrid vehicle drive system according to the present embodiment includes an engine having the system configuration according to the first embodiment (the engine shown in FIG. 1) as the power unit. In FIG. 7, the same elements as those of the first embodiment are denoted by the same reference numerals.

  This drive system includes a motor 72 as another power unit. In addition, a generator 76 that generates electric power upon receiving a driving force is also provided. The engine body 2, the motor 72, and the generator 76 are connected to each other via a power split mechanism 70. A reduction gear 74 is connected to the rotating shaft of the motor 72 connected to the power split mechanism 70. The speed reducer 74 connects the rotation shaft of the motor 72 and the drive shaft 90 connected to the drive wheels 92. The power split mechanism 70 is a device that splits the driving force of the engine body 2 into the generator 76 side and the speed reducer 74 side. The distribution of the driving force by the power split mechanism 70 can be arbitrarily changed.

  The drive system further includes an inverter 78, a converter 80, and a high voltage battery 82. Inverter 78 is connected to generator 76 and motor 72, and is also connected to high voltage battery 82 via converter 80. The electric power generated by the generator 76 can be supplied to the motor 72 via the inverter 78, or the high voltage battery 82 can be charged via the inverter 78 and the converter 80. Further, the electric power charged in the high voltage battery 82 can be supplied to the motor 72 via the converter 80 and the inverter 78.

  According to this drive system, the motor 72 can be stopped and the driving wheel 92 can be rotated only by the driving force of the engine body 2, and conversely, the engine body 2 is stopped and driven only by the driving force of the motor 72. The ring 92 can also be rotated. It is also possible to operate both the motor 72 and the engine main body 2 and rotate the driving wheels 92 by both driving forces. Further, according to this drive system, the motor 72 can also function as a starter of the engine body 2. That is, when the engine body 2 is started, the engine body 2 can be cranked by inputting a part or all of the driving force of the motor 72 to the engine body 2 via the power split mechanism 70. Further, the stopped engine body 2 can be forcibly rotated as necessary regardless of the start of the engine body 2.

  The drive system of this embodiment is controlled by the ECU 60. The ECU 60 comprehensively controls not only the engine system including the engine body 2 but also the entire drive system including the motor 72, the generator 76, the power split mechanism 70, the inverter 78, the converter 80, and the like. FIG. 8 is a flowchart showing a routine for hydrogenation control executed by the ECU 60 in the present embodiment. The routine shown in FIG. 8 is periodically executed for each predetermined crank angle.

  In the first step S600 of the routine shown in FIG. 8, it is determined whether or not the engine body 2 is in a combustion operation. When the engine main body 2 is in a combustion operation, hydrogen gas is added to the liquid fuel by the processes in steps S602 to S608.

  In step S602, the required hydrogen addition ratio corresponding to the operating state of the engine body 2 is obtained from a map stored in advance. For example, a hydrogen addition ratio for suppressing knocking is required during high load operation, and a hydrogen addition ratio for suppressing misfire and combustion fluctuation is required during low load operation. In the next step S604, a required hydrogen generation amount corresponding to the required hydrogen addition ratio is obtained.

  In the next step S606, the hydrogen generation process corresponding to the required hydrogen generation amount is executed by the operation of the hydrogen generator 50. The hydrogen gas generated by the hydrogen generator 50 is microbubbled by the microbubble generator 52 and mixed with the liquid fuel (step S608). By supplying the liquid fuel mixed with hydrogen gas to the engine body 2, during high load operation, knocking is quickly suppressed and high-efficiency operation such as advance of ignition timing becomes possible. Further, during low load operation, it is possible to quickly suppress misfires and combustion fluctuations and expand the lean burn region.

  On the other hand, when the combustion of the engine body 2 is stopped in the determination in step S600, the determination in step S610 is subsequently performed. In step S610, the presence or absence of a request for catalyst processing is determined from the state of the catalyst 20. When the NOx occlusion amount of the catalyst 20 is close to the limit, it is determined that the reduction treatment of the catalyst 20 is necessary. Further, when the temperature of the catalyst 20 is lower than an appropriate temperature at which the purification performance is maximized, it is determined that the catalyst 20 needs to be warmed up. If there is any catalyst processing request as a result of the determination in step S610, the addition of hydrogen gas to the liquid fuel and the liquid fuel to which hydrogen gas has been added by the processing in steps S616 to S624 described below. Supply to the catalyst 20 is performed.

  First, in step S616, a required hydrogen addition ratio corresponding to the content of the catalyst processing request (reduction processing request or warm-up processing request) is obtained from a map stored in advance. In step S618, a required hydrogen production amount corresponding to the required hydrogen addition ratio is obtained. In the next step S620, a hydrogen generation process corresponding to the required hydrogen generation amount is executed by the operation of the hydrogen generator 50. The hydrogen gas generated by the hydrogen generator 50 is microbubbled by the microbubble generator 52 and mixed with the liquid fuel (step S622).

  In the next step S624, the power split mechanism 70 is operated, and part or all of the driving force of the motor 72 is input to the engine body 2 via the power split mechanism 70. Thus, the engine body 2 is forcibly rotated by the driving force of the motor 72 and operates as a pump that sucks air from the intake passage and discharges it to the exhaust passage 6.

  In step 624, simultaneously with the forced rotation of the engine main body 2 by the motor 72, an injection command is supplied from the ECU 60 to the in-cylinder injector, and liquid fuel (hydrogenated fuel) mixed with hydrogen gas is supplied from the in-cylinder injector to the combustion chamber. Is injected into. In this case, the in-cylinder injector of each cylinder may be operated, or only the in-cylinder injector of a specific cylinder may be operated. Alternatively, the number of in-cylinder injectors to be operated may be determined according to the amount of hydrogenated fuel supplied.

  The hydrogenated fuel injected from the in-cylinder injector into the combustion chamber is discharged into the exhaust passage 6 as it is together with the air sucked from the intake passage by the pump action of the engine body 2. At this time, if the required catalyst process is a reduction process, the throttle of the intake passage is closed. By closing the throttle, the amount of intake air can be reduced, and the dilution of hydrogenated fuel with air can be reduced. As a result, a gas having a very high hydrogen concentration flows into the catalyst 20, and the atmosphere around the catalyst 20 is a rich reducing atmosphere.

  When the requested catalyst process is a warm-up process, the throttle is opened and an amount of air corresponding to the fuel injection amount is drawn into the combustion chamber. The opening of the throttle is controlled so that the air-fuel ratio of the hydrogenated fuel and air becomes a predetermined air-fuel ratio suitable for the combustion reaction on the catalyst 20. The mixture of hydrogenated fuel and air is supplied to the catalyst 20 through the exhaust passage 6, and the hydrogenated fuel and oxygen cause a combustion reaction on the catalyst 20, whereby the temperature of the catalyst 20 rises.

  When the reduction process or warm-up process of the catalyst 20 is completed, the request for the catalyst process is withdrawn in the determination of step S610. In that case, the hydrogen generation process in the hydrogen generator 50 is stopped (step S612), and then the microbubble generation process by the microbubble generator 52 is also stopped (step S614).

  According to the hydrogen addition control routine described above, during the combustion operation of the engine body 2, the knock limit and the lean limit are expanded by adding hydrogen to the liquid fuel according to the operating state of the engine body 2, thereby increasing the engine body. 2 can be operated efficiently. When the combustion of the engine body 2 is stopped, the hydrogenated fuel is injected while rotating the engine body 2 by the motor 72, so that the reduction performance and warming of the catalyst 20 are not affected without affecting the operation performance of the engine body 2. Machine processing can be performed efficiently.

  In the present embodiment, the “control device” according to the eighth aspect of the present invention is realized by the ECU 60 executing the hydrogen addition control routine.

Others.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the following modifications may be made.

  The engine shown in FIG. 1 includes the in-cylinder injector 18 that directly injects fuel into the combustion chamber 10 as a fuel injection device, but may be a port injector that injects fuel into the intake port. Moreover, although the engine shown in FIG. 1 is comprised as a gasoline engine which uses gasoline as a fuel, this invention is applicable also to the diesel engine which uses light oil as a fuel.

  In the configuration of FIG. 7, the hybrid vehicle is configured to be able to travel by both the engine body 2 and the motor 72, but the hybrid vehicle only needs to be capable of traveling by at least the motor 72 in applying the present invention. That is, the engine body 2 may be dedicated to power generation.

It is a figure which shows the system configuration | structure of the hydrogen utilization internal combustion engine as Embodiment 1 of this invention. It is a flowchart shown about the routine of hydrogenation control performed in Embodiment 1 of this invention. It is a flowchart shown about the routine of hydrogenation control performed in Embodiment 2 of this invention. It is a flowchart shown about the routine of hydrogenation control performed in Embodiment 3 of this invention. It is a flowchart shown about the routine of hydrogenation control performed in Embodiment 4 of this invention. It is a flowchart shown about the routine of hydrogenation control performed in Embodiment 5 of this invention. It is a figure which shows the structure of the drive system of the hybrid vehicle to which the hydrogen utilization internal combustion engine of this invention was applied. It is a flowchart shown about the routine of hydrogenation control performed in Embodiment 6 of this invention.

Explanation of symbols

2 Engine body 4 Intake passage 6 Exhaust passage 10 Combustion chamber 18 In-cylinder injector 20 Catalyst 30 Fuel tank 32 Fuel pump 36 Fuel supply line 40 Water tank 42 Water pump 44 Water supply line 46 Hydrogen gas supply line 50 Hydrogen generator 52 Micro bubble Generator 54 Fuel property sensor 60 ECU
62 Operating state measuring device 64 Atmospheric state measuring device 70 Power split mechanism 72 Motor 74 Reducer 76 Generator 78 Inverter 80 Converter 82 High voltage battery

Claims (6)

In a hydrogen-based internal combustion engine that can use hydrocarbon-based liquid fuel and hydrogen gas as fuel,
A fuel injection device for injecting liquid fuel; and
Storage means for storing liquid hydrogen compounds;
Hydrogen generating means for generating hydrogen gas from the liquid hydrogen compound stored in the storage means;
Hydrogen mixing means for mixing the hydrogen gas generated by the hydrogen generating means into fine bubbles and mixing the liquid fuel supplied to the fuel injection device;
Determining means for determining the necessity of supplying hydrogen gas to the internal combustion engine;
A hydrogen mixing amount determining means for determining a necessary hydrogen mixing amount when it is determined by the determining means that hydrogen gas needs to be supplied;
Control means for operating the hydrogen generating means to generate the amount of hydrogen determined by the hydrogen mixing amount determining means when it is determined by the determining means that hydrogen gas needs to be supplied;
An internal combustion engine using hydrogen. 2. The hydrogen-using internal combustion engine according to claim 1, wherein the hydrogen mixture amount determining means determines a necessary hydrogen mixture amount based on an operating state of the internal combustion engine. 2. The hydrogen-utilizing internal combustion engine according to claim 1, wherein the hydrogen mixture amount determining means determines a necessary hydrogen mixture amount based on properties of the liquid fuel. 2. The hydrogen-using internal combustion engine according to claim 1, wherein the hydrogen mixing amount determining means determines a necessary hydrogen mixing amount based on an atmospheric state. 2. The hydrogen-using internal combustion engine according to claim 1, wherein the hydrogen mixing amount determining means determines a necessary hydrogen mixing amount based on a state of a catalyst disposed in an exhaust passage of the internal combustion engine. In the control apparatus of the hybrid vehicle which has a hydrogen utilization internal combustion engine and a motor of Claim 5, and can drive a vehicle at least with the motor,
When it is determined that it is necessary to supply hydrogen gas, the internal combustion engine is forcibly rotated by the motor in a state where combustion of the internal combustion engine is stopped, and the hydrogen generation means and the hydrogen mixing means are A control device for a hybrid vehicle having a hydrogen-using internal combustion engine, wherein the control device is operated and injects liquid fuel mixed with hydrogen gas from the fuel injection device.

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