JP4333656B2 - Internal combustion engine using hydrogen - Google Patents

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

  The conventional hydrogen-utilized internal combustion engine uses a hydrogen tank as means for storing hydrogen gas. However, hydrogen gas, which is a gaseous fuel, is inferior in mounting efficiency when mounted on a vehicle as compared with liquid fuel such as gasoline. For this reason, in recent years, it has been proposed to store hydrogen gas in a liquid (liquid hydrogen compound) state with high mounting efficiency by generating hydrogen gas from the liquid hydrogen compound on the vehicle.

  As a method for generating hydrogen gas from a liquid hydrogen compound, in addition to electrolysis, decomposition by low-temperature plasma (see JP-A-2001-335302), reduction with a highly active metal (JP-A-2004-123517, Various methods have been proposed, such as Japanese Unexamined Patent Application Publication No. 2003-212501.

  However, no matter which method is used, it takes a certain amount of time for the generated hydrogen gas to reach the injection valve. For this reason, when it is desired to inject hydrogen gas immediately after the start of the internal combustion engine, it is necessary to store hydrogen gas for use immediately after the start. A tank is conceivable as a means for storing hydrogen gas, but it is desirable to avoid storing hydrogen gas in the tank as much as possible in consideration of the ability to be mounted on a vehicle.

  The present invention has been made to solve the above-described problems, and can add and inject hydrogen gas to liquid fuel immediately after starting the internal combustion engine without requiring a tank for storing hydrogen gas. An object of the present invention is to provide a hydrogen-utilized internal combustion engine.

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
A fuel tank for storing liquid fuel;
Hydrogen generating means for generating hydrogen gas from a liquid hydrogen compound;
Hydrogen mixing means for mixing hydrogen gas generated by the hydrogen generating means with liquid fuel supplied from the fuel tank to the fuel injection device;
A circulation means for circulating liquid fuel between the fuel injection device and the hydrogen mixing means;
When starting or predicting the start of the internal combustion engine, prior to the start of fuel injection by the fuel injection device, the hydrogen generating means is operated to generate hydrogen gas while operating the circulating means to circulate liquid fuel. A control means for operating the hydrogen mixing means to mix the produced hydrogen gas with the liquid fuel;
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 the first invention, the hydrogen gas is generated from the liquid hydrogen compound prior to the start of fuel injection, and the generated hydrogen gas is mixed with the circulating liquid fuel. Can be supplied from the first fuel injection. Furthermore, the generation of hydrogen gas is performed after the start operation of the internal combustion engine is detected or after the start is predicted, and the generated hydrogen gas is stored in the circulating liquid fuel. Tanks that can be stored in a state can be eliminated.

  According to the second aspect of the invention, the hydrogen gas is made into fine bubbles and mixed with the liquid fuel, whereby the dissolution of the hydrogen gas into the liquid fuel can be promoted, and the liquid fuel with a high hydrogen gas addition ratio is supplied. It becomes possible.

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.

  A flow path switching valve 54 is disposed upstream of the fuel pump 32 in the fuel supply line 36. The flow path switching valve 54 is a three-way valve having one outlet port and two inlet ports, and the downstream side of the fuel supply line 36 (the fuel pump 32 side) is connected to the outlet port. The upstream side (fuel inlet side) of the fuel supply line 36 is connected to the fuel supply line 36. A fuel circulation line 38 is connected to the other inlet port of the flow path switching valve 54. The fuel circulation line 38 is arranged in parallel with the fuel supply line 36, and the other end thereof is in the vicinity of the in-cylinder injector 18 in the fuel supply line 36. Specifically, the liquid fuel is supplied to the in-cylinder injector 18 of each cylinder. Is connected to a delivery pipe 36a for distributing to

  The inlet port of the flow path switching valve 54 is normally set on the upstream side of the fuel supply line 36. In this case, as described above, the liquid pump is sucked up from the fuel tank 30 by the operation of the fuel pump 32 and the pressurized liquid fuel is supplied to the in-cylinder injector 18. On the other hand, when the inlet port of the flow path switching valve 54 is switched to the fuel circulation line 38, a liquid fuel circulation system including the fuel supply line 36 and the fuel circulation line 38 is formed. In this case, the liquid fuel can be circulated in a high pressure state by stopping the fuel injection of the in-cylinder injector 18 and operating the fuel pump 32. The fuel pump 32 and the flow path switching valve 54 constitute a circulation means for circulating the liquid fuel in the circulation system.

  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. 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. 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.

  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.

  The engine of this embodiment includes an ECU (Electronic Control Unit) 60 as its control device. 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, the hydrogen generator 50, and the flow path switching valve 54 are connected to the output side of the ECU 60. Yes. On the input side of the ECU 60, there is an operating state measuring device 62 that acquires information relating to the operating state of the engine body 2 (accelerator opening, vehicle speed, engine speed, air-fuel ratio, water temperature, knock signal, etc.), and a driver's seat door. Various sensors such as a door switch 64 that detects opening are connected. The ECU 60 controls each device according to a predetermined control program based on the output of each sensor.

  With the system configuration as described above, according to the engine of the present embodiment, when it is necessary to add hydrogen gas to the liquid fuel, the hydrogen generator 50 immediately generates hydrogen gas from water, and the generated hydrogen gas Can be microbubbled and mixed with liquid fuel. The routine shown in the flowchart of FIG. 2 is a routine for hydrogenation control at the time of engine start, which is executed by the ECU 60 in the present embodiment. Hereinafter, the specific content of the hydrogen addition control executed at the time of engine start will be described along the flowchart of FIG. Note that 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, it is determined from the signal of the door switch 64 whether the driver's seat door has been opened. When the driver's seat door opens, the signal of the door switch 64 switches from off to on. It is estimated that the driver's intention to start the engine body 2 is opened by opening the door of the driver's seat. That is, the start of the engine body 2 is predicted. While the driver's seat door is closed, the processing in the subsequent steps is not performed, and only the determination in step S100 is repeatedly executed.

  When the door of the driver's seat is opened, that is, when the start of the engine body 2 is predicted, the determination in step S102 is executed. In step S102, it is determined whether or not an execution condition for hydrogenation at the time of engine start is satisfied. The execution conditions of hydrogen addition at the time of engine start include, for example, that the cooling water temperature is lower than the reference temperature, the atmospheric state is in a state where misfire is easily caused during low load operation, or the inside of the fuel tank 30 The property of the liquid fuel is a property of fuel that easily misfires. When the hydrogenation execution condition is not satisfied, the hydrogen generation process in the hydrogen generator 50 is not executed (step S122), and the microbubble generation process by the microbubble generator 52 is not executed (step S124).

  If the execution condition for hydrogenation is satisfied, hydrogen gas is added to the liquid fuel by the processing after step S104. First, in step S104, a hydrogen addition ratio required at the time of starting the engine is obtained from a 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 next step S106, the required hydrogen production amount (necessary production amount of hydrogen gas) is calculated from the flow rate of liquid fuel (discharge flow rate of the hydraulic pump 32) and the required hydrogen addition ratio when the liquid fuel is circulated in the circulation system. ) Is required.

  In step S108, pressurization of the liquid fuel is started by the operation of the fuel pump 32, and the inlet port of the flow path switching valve 54 is switched to the fuel circulation line 38. Thus, the high-pressure liquid fuel pressurized by the fuel pump 32 returns to the fuel supply line 36 again through the fuel circulation line 38 and circulates in the liquid fuel circulation system including the fuel supply line 36 and the fuel circulation line 38. To do. The discharge flow rate of the fuel pump 32 at this time is set to a predetermined circulation flow rate.

  In step S <b> 110, 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. In the next step S112, the hydrogen gas generated by the hydrogen generator 50 is microbubbled by the microbubble generator 52, and the microbubbled hydrogen gas is mixed with the liquid fuel circulating in the circulation system. The In this way, by circulating the liquid fuel, and hydrogen gas is microbubbled and mixed with the circulating liquid fuel, the hydrogen gas generated before starting the engine body 2 can be stored in the liquid fuel. .

  After the hydrogen gas is added to the liquid fuel by the processes in steps S104 to S112, the determination in step S114 is performed. In step S114, it is determined whether or not there is a request for starting the engine body 2. When a start switch such as an ignition switch is switched from OFF to ON, it can be determined that a start request has been made. If there is a start request, engine start control for starting the engine body 2 such as cranking by a starter is executed (step S116).

  After the engine start control is executed, it is determined in step S118 whether or not the start of the engine body 2 has been completed. For example, when the engine speed increases to a predetermined reference speed, it can be determined that the start is completed. Until the start of the engine body 2 is completed, the switching operation of the flow path switching valve 54 is not performed unless the fuel pressure falls below a predetermined value, and the circulation of the liquid fuel in the circulation system is continued.

  When the start of the engine body 2 is completed, the process of step S120 is executed. In step S120, the circulation of the liquid fuel is stopped by the switching operation of the flow path switching valve 54 and returned to the normal fuel supply system that supplies fuel from the fuel tank 30 to the in-cylinder injector 18. At this time, since the required amount of hydrogen gas is already added to the liquid fuel in the fuel supply line 36, the liquid fuel in which the hydrogen gas is sufficiently mixed can be injected immediately after the start of fuel injection. it can.

  According to the hydrogen addition control routine described above, hydrogen injection is generated by the hydrogen generator 50 prior to the start of the engine body 2, and the generated hydrogen gas is mixed with the circulated liquid fuel to start fuel injection. Sometimes liquid fuel with added hydrogen gas can be supplied from the first fuel injection. In addition, since the hydrogen gas is microbubbled and mixed with the liquid fuel, the dissolution of the hydrogen gas into the liquid fuel can be promoted, and the liquid fuel with a high hydrogen gas addition ratio can be supplied. Therefore, according to the engine of the present embodiment, stable combustion can be realized by adding hydrogen gas immediately after the engine main body 2 is started, and the air-fuel ratio can be made lean and the ignition timing can be greatly retarded. Thus, the catalyst 20 can be quickly heated.

  Furthermore, according to the hydrogen addition control routine described above, hydrogen gas is generated from water when the start of the engine body 2 is predicted, and the generated hydrogen gas is stored as microbubbles in the circulating liquid fuel. . Therefore, in the engine of this embodiment, a tank for storing hydrogen gas in a gas state can be eliminated, and the manufacturing cost can be reduced correspondingly, and the mounting property to the vehicle is improved.

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

Embodiment 2. FIG.
The second embodiment of the present invention will be described below with reference to FIGS.

  FIG. 3 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. 3, 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. 4 is a flowchart showing a routine for hydrogenation control executed by the ECU 60 in the present embodiment. This routine also includes engine start control for starting the engine body 2 during traveling by the motor 72. Hereinafter, the specific contents of the hydrogenation control in the hybrid vehicle will be described with reference to the flowchart of FIG. Note that the routine shown in FIG. 4 is periodically executed for each predetermined crank angle.

  In the first step S200 of the routine shown in FIG. 4, it is determined whether or not an execution condition for hydrogenation is satisfied. If the engine main body 2 has not yet started at the present time, the coolant temperature is below the reference temperature, the atmospheric condition is likely to be misfired during low-load operation, or the fuel tank 30 It is determined as an execution condition for hydrogenation that the liquid fuel in the tank is easily misfired. On the other hand, when the engine main body 2 has already started at the present time, the engine main body 2 is further operated in an operation region where knocking may occur, or is operated in an operation region where combustion fluctuations may occur. It is also determined as an execution condition for hydrogenation. When the hydrogenation execution condition is not satisfied, the hydrogen generation process in the hydrogen generator 50 is not executed (step S224), and the microbubble generation process by the microbubble generator 52 is not executed (step S226).

  If the execution conditions for hydrogenation are satisfied, hydrogen gas is added to the liquid fuel by the processing after step S202. First, in step S202, a required hydrogen addition ratio corresponding to the operating state of the engine body 2 is obtained from a map stored in advance. If the engine body 2 has not yet been started at the present time, the required hydrogen addition rate is the hydrogen addition rate required at the time of engine startup. On the other hand, when the engine body 2 has already been started at the present time, the required hydrogen addition rate is the hydrogen addition rate required from the accelerator opening, the engine speed, and the like.

  In step S204, a required hydrogen production amount corresponding to the required hydrogen addition rate is obtained. If the engine main body 2 has not yet started at the present time, the required hydrogen generation amount is determined by the flow rate of liquid fuel (discharge flow rate of the hydraulic pump 32) and the required hydrogen addition ratio when the liquid fuel is circulated in the circulation system. Is calculated from On the other hand, when the engine main body 2 has already been started at the present time, the required hydrogen generation amount is calculated from the required hydrogen addition rate, the required load of the engine main body 2, the calorific value per unit amount of hydrogen gas, and the like. .

  In the next step S206, it is determined whether or not the engine start request flag is on. The engine start request flag is switched from off to on when the ECU 60 determines that the engine body 2 needs to be started. The engine start request flag is switched from ON to OFF again when the start of the engine body 2 is completed.

  When the engine start request flag is on, hydrogen addition control at the time of engine start is executed by the processing of steps S212 to S222. First, in step S212, pressurization of the liquid fuel is started by the operation of the fuel pump 32, and the inlet port of the flow path switching valve 54 is switched to the fuel circulation line 38. Thus, the high-pressure liquid fuel pressurized by the fuel pump 32 returns to the fuel supply line 36 again through the fuel circulation line 38 and circulates in the liquid fuel circulation system including the fuel supply line 36 and the fuel circulation line 38. To do. The discharge flow rate of the fuel pump 32 at this time is set to a predetermined circulation flow rate.

  In step S214, 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. In the next step S216, the hydrogen gas generated by the hydrogen generator 50 is microbubbled by the microbubble generator 52, and the microbubbled hydrogen gas is mixed with the liquid fuel circulating in the circulation system. The In this way, by circulating the liquid fuel, and hydrogen gas is microbubbled and mixed with the circulating liquid fuel, the hydrogen gas generated before starting the engine body 2 can be stored in the liquid fuel. .

  After the hydrogen gas is added to the liquid fuel by the processes in steps S212 to S216, engine start control for starting the engine body 2 is executed (step S218). In the engine start control, part or all of the driving force of the motor 72 is input to the engine body 2 via the power split mechanism 70 by the operation of the power split mechanism 70. Thereby, the engine main body 2 is cranked by the driving force of the motor 72, and then the hydrogen added fuel is injected from the in-cylinder injector 18, whereby the engine main body 2 is started.

  After the engine start control is executed, it is determined in step S220 whether or not the engine main body 2 has been started. For example, when the engine speed increases to a predetermined reference speed, it can be determined that the start is completed. Until the start of the engine body 2 is completed, the switching operation of the flow path switching valve 54 is not performed unless the fuel pressure falls below a predetermined value, and the circulation of the liquid fuel in the circulation system is continued.

  When the start of the engine body 2 is completed, the process of step S222 is executed. In step S222, the circulation of the liquid fuel is stopped by the switching operation of the flow path switching valve 54 and returned to the normal fuel supply system that supplies fuel from the fuel tank 30 to the in-cylinder injector 18. At this time, since the required amount of hydrogen gas is already added to the liquid fuel in the fuel supply line 36, the liquid fuel in which the hydrogen gas is sufficiently mixed can be injected immediately after the start of fuel injection. it can.

  When the start of the engine body 2 is completed, the engine start request flag is switched from on to off. As a result, the determination result in step S206 is No at the next execution of this routine. In this case, hydrogen addition control during engine operation is executed by the processing of steps S208 and S210. First, in step S208, 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 S210). 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.

  According to the hydrogen addition control routine described above, during traveling by the motor 72, hydrogen gas is generated by the hydrogen generator 50 prior to starting the engine body 2, and the generated hydrogen gas is mixed with the circulating liquid fuel. Thus, at the start of fuel injection, liquid fuel to which hydrogen gas has been added can be supplied from the first fuel injection. In addition, since the hydrogen gas is microbubbled and mixed with the liquid fuel, the dissolution of the hydrogen gas into the liquid fuel can be promoted, and the liquid fuel with a high hydrogen gas addition ratio can be supplied. Therefore, according to the hybrid vehicle drive system of the present embodiment, stable combustion can be realized by adding hydrogen gas immediately after the engine body 2 is started, and the air-fuel ratio can be greatly reduced and the ignition timing can be greatly increased. Thus, the catalyst 20 can be raised in temperature early by slowing down.

  Furthermore, according to the hydrogen addition control routine described above, hydrogen gas is generated from water immediately before the engine main body 2 is started, and the generated hydrogen gas is stored as microbubbles in the circulating liquid fuel. Therefore, the hybrid vehicle drive system of the present embodiment does not require a tank for storing hydrogen gas in a gaseous state, and accordingly, the manufacturing cost can be reduced, and the mountability to the vehicle is improved. .

  In the present embodiment, the “control device” according to the first aspect of the present invention is realized by the ECU 60 executing the above hydrogenation 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. 3, the hybrid vehicle is configured to be able to travel by both the engine main 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 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 2 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 36a Delivery pipe 38 Fuel circulation line 40 Water tank 42 Water pump 44 Water supply line 46 Hydrogen gas supply line 50 Hydrogen generator 52 Micro bubble generator 54 Flow path switching valve 60 ECU
62 Operating state measuring device 64 Door switch 70 Power split mechanism 72 Motor 74 Reducer 76 Generator 78 Inverter 80 Converter 82 High voltage battery

Claims (2)

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
A fuel tank for storing liquid fuel;
Hydrogen generating means for generating hydrogen gas from a liquid hydrogen compound;
Hydrogen mixing means for mixing hydrogen gas generated by the hydrogen generating means with liquid fuel supplied from the fuel tank to the fuel injection device;
A circulation means for circulating liquid fuel between the fuel injection device and the hydrogen mixing means;
When starting or predicting the start of the internal combustion engine, prior to the start of fuel injection by the fuel injection device, the hydrogen generating means is operated to generate hydrogen gas while operating the circulating means to circulate liquid fuel. A control means for operating the hydrogen mixing means to mix the produced hydrogen gas with the liquid fuel;
An internal combustion engine using hydrogen. 2. The hydrogen-using internal combustion engine according to claim 1, wherein the hydrogen mixing means includes means for generating hydrogen gas fine bubbles, and the hydrogen gas fine bubbles are mixed with the liquid fuel.

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