JP5835281B2 - Engine system - Google Patents

Description

  The present invention relates to an engine system, and more particularly to an engine system that reforms a compound gas containing hydrogen to generate hydrogen gas and burns the reformed gas containing hydrogen as a main component in the engine.

  A related technique for generating hydrogen gas by reforming a compound gas containing hydrogen is disclosed in Patent Document 1 below. In Patent Document 1, in a reactor (reformer), a hydrocarbon oxidation reaction (exothermic reaction) as a reforming fuel and a hydrocarbon reforming reaction (endothermic reaction) are simultaneously performed on a catalyst. Thus, a reformed gas containing hydrogen is generated. An ejector having a main channel for injecting reforming air from the nozzle and a sub-channel for sucking reforming fuel (hydrocarbon) by injection of the reforming air is provided on the upstream side of the reactor. The reforming air and the reforming fuel are mixed in the ejector and then supplied to the reactor.

JP 2005-289658 A JP 2007-42309 A

  In Patent Document 1, reforming air (oxygen-containing gas) and reforming fuel are used for reforming reforming fuel (compound gas containing hydrogen) in a reactor (reformer) to generate hydrogen gas. Fuel is mixed with an ejector and supplied to the reactor. In this case, the ratio of reforming fuel to hydrogen gas in the reactor (hydrogen generation ability) is greatly influenced by the catalyst temperature of the reactor. Since the catalyst temperature is determined mainly by the mixing ratio (air-fuel ratio Air / Fuel) of reforming air and reforming fuel supplied from the ejector to the reactor, the controllability of hydrogen generation ability in the reactor is controlled. In order to improve, the controllability of the air-fuel ratio Air / Fuel from the ejector to the reactor is important. However, the adjustment of reforming air and reforming fuel by the ejector has a large pressure effect, and when the reformed gas generated in the reactor is supplied as fuel to the intake passage of the engine, it depends on the operating conditions of the engine. The air-fuel ratio Air / Fuel at the ejector varies with the changing intake pressure. When the air-fuel ratio Air / Fuel in the reactor varies from the ejector, the rate at which the reforming fuel is reformed into hydrogen gas also varies in the reactor, and the controllability of the hydrogen generation ability is reduced.

  In the present invention, when a compound gas containing hydrogen and an oxygen-containing gas are mixed by an ejector and supplied to a reformer, and the reformed gas generated in the reformer is supplied as fuel to an intake passage of the engine, The purpose is to suppress a decrease in the controllability of the hydrogen generation ability in the reformer due to a change in intake pressure.

  The engine system according to the present invention employs the following means in order to achieve the above-described object.

An engine system according to the present invention includes a supply device that supplies a compound gas containing hydrogen, a throttle portion, a main flow path through which the compound gas supplied from the supply device passes, and a main flow path through which an oxygen-containing gas flows. An ejector in which an oxygen-containing gas sucked from the sub-flow channel can be mixed with the compound gas by depressurization at the throttle portion of the compound gas passing through the main flow channel. By reacting an ejector and the compound gas mixed in the ejector with an oxygen-containing gas on a catalyst, heat is generated by an oxidation reaction of a part of the compound gas, and the compound using the generated heat a reformer for generating hydrogen gas by the decomposition reaction of the gas, the reformed gas generated in the reformer is supplied to the intake passage, and an engine to burn the reforming gas in the cylinder, Ro in the intake passage of the engine Branched from the downstream side of the torque valve, through secondary flow channel and the communication of the ejector, and the introduction passage for introducing intake air of the engine to the ejector as the oxygen-containing gas, with respect to the intake pressure change in the engine, the reformer from the ejector A mixing ratio adjusting unit that adjusts the amount of oxygen-containing gas sucked into the ejector so as to suppress fluctuations in the mixing ratio of the compound gas and the oxygen-containing gas supplied to the engine. The main feature of the present invention is that it has a sub-introduction passage for branching from the upstream side of the throttle valve in the intake passage, communicating with the sub-passage of the ejector, and introducing the intake air of the engine as an oxygen-containing gas to the ejector .

Another engine system according to the present invention includes a supply device that supplies a compound gas containing hydrogen, a throttle unit, a main passage through which the compound gas supplied from the supply device passes, a main passage, and an oxygen-containing And an oxygen-containing gas sucked from the sub-flow channel is mixed with the compound gas by depressurization at the throttle portion of the compound gas passing through the main flow channel. A possible ejector, and the compound gas mixed in the ejector and the oxygen-containing gas are reacted on a catalyst to generate heat by an oxidation reaction of a part of the compound gas, and the generated heat is used. A reformer that generates hydrogen gas by a decomposition reaction of the compound gas, an engine in which the reformed gas generated in the reformer is supplied to the intake passage and combusts the reformed gas in a cylinder, and an intake passage of the engine In Branched from the downstream side of the throttle valve, through secondary flow channel and the communication of the ejector, and the introduction passage for introducing intake air of the engine to the ejector as the oxygen-containing gas, with respect to the intake pressure change in the engine, the reformer from the ejector A mixing ratio adjusting unit that adjusts the amount of oxygen-containing gas sucked into the ejector so as to suppress fluctuations in the mixing ratio of the compound gas and the oxygen-containing gas supplied to the The gist of the present invention is to have a sub-introduction path for introducing air in the atmosphere into the ejector as the contained gas .

  In one aspect of the present invention, it is preferable that the flow passage area of the sub introduction path is smaller than the flow passage area of the introduction path.

  According to the present invention, the oxygen sucked into the ejector so as to suppress the fluctuation in the mixing ratio of the compound gas containing hydrogen and the oxygen-containing gas supplied from the ejector to the reformer with respect to the change in the intake pressure of the engine. By adjusting the amount of contained gas or the amount of compound gas supplied to the reformer, it is possible to suppress the fluctuation in the ratio of reforming compound gas to hydrogen gas in the reformer. It can suppress that the controllability of hydrogen production ability falls.

It is a figure which shows schematic structure of the engine system which concerns on Embodiment 1 of this invention. It is a figure which shows the result of having measured the relationship of the mixing ratio of the reforming air and reforming fuel gas which are supplied to the reformer from an ejector with respect to engine intake pressure. It is a figure which shows an example of the relationship between the intake pressure for maintaining air-fuel ratio Air / Fuel to a target value, and the opening degree of a reforming air control valve. It is a figure which shows schematic structure of the engine system which concerns on Embodiment 2 of this invention. It is a figure which shows schematic structure of the engine system which concerns on Embodiment 3 of this invention. It is a figure which shows an example of the relationship between the opening degree of the throttle valve for the air-fuel ratio Air / Fuel being maintained at a target value, and the opening degree of a reforming air control valve. It is a figure which shows schematic structure of the engine system which concerns on Embodiment 4 of this invention. It is a figure which shows an example of the relationship between the intake pressure for maintaining air-fuel ratio Air / Fuel to a target value, and the injection quantity of a subinjector. It is a figure which shows schematic structure of the engine system which concerns on Embodiment 5 of this invention. It is a figure which shows schematic structure of the engine system which concerns on Embodiment 6 of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

“Embodiment 1”
FIG. 1 is a diagram showing a schematic configuration of an engine system according to Embodiment 1 of the present invention. A fuel tank 109 as a fuel storage device is filled with a compound gas containing hydrogen as a reforming fuel gas at a high pressure. As the reforming fuel gas here, for example, a compound gas of nitrogen and hydrogen such as ammonia gas (NH ₃ ) and hydrazine gas (N ₂ H ₄ ) can be used. Alternatively, as the reforming fuel gas, for example, a hydrocarbon gas such as methane (CH ₄ ) or propane (LPG) can be used. The reforming fuel gas 100a filled in the fuel tank 109 is supplied to an injector 102 as a fuel gas supply device through a fuel gas supply passage 110, and is supplied to the ejector 101 by being injected from the injector 102. The

  The ejector 101 includes a main channel 101a through which the reforming fuel gas 100a passes, and a sub channel 101b that communicates with the main channel 101a and through which the reforming air 100c as an oxygen-containing gas (a gas containing oxygen) passes. Is formed. In the middle of the main channel 101a, an orifice (throttle portion) 101c with a narrowed tube diameter is provided. The injector 102 is arranged facing the main flow path 101a (upstream side of the orifice 101c) of the ejector 101, and the reforming fuel gas 100a injected from the injector 102 is positioned upstream of the orifice 101c in the main flow path 101a. To be supplied. An intake passage 107 of the engine 108 branches downstream from the throttle valve 106 (directly below the throttle valve 106), and the branched air introduction path 111 communicates with the sub-flow path 101b. Then, the reforming air 100c (intake of the engine 108) is introduced into the sub-flow channel 101b. A reforming air control valve 112 is provided in the middle of the air introduction path 111. When the reforming fuel gas 100a injected from the injector 102 into the main flow path 101a passes through the orifice 101c, the flow velocity increases and the pressure decreases. Due to the negative pressure generated at this time, the reforming air 100c is sucked from the sub-flow channel 101b, flows into the main flow channel 101a, and is mixed with the reforming fuel gas 100a. The mixed gas 100d of the reforming fuel gas 100a and the reforming air 100c is supplied to the reformer 104 through the main channel 101a (downstream from the orifice 101c).

In the reformer 104, a reforming catalyst for generating hydrogen gas (H ₂ ) by reforming the reforming fuel gas 100a by a decomposition reaction of the reforming fuel gas (compound gas containing hydrogen) 100a. 103 is provided. The reformer 104 causes the reforming fuel gas 100a mixed with the ejector 101 and the reforming air 100c to react on the reforming catalyst 103, thereby oxidizing a part of the reforming fuel gas 100a. . Since this oxidation reaction is an exothermic reaction, heat is generated by the oxidation reaction, and the temperature of the reforming catalyst 103 rises. The heat generated by the oxidation reaction is used for the decomposition reaction of the reforming fuel gas 100a, which is an endothermic reaction. As a result, the decomposition reaction of the reforming fuel gas 100a proceeds on the reforming catalyst 103, and the reformed gas 100e mainly containing hydrogen is generated. In that case, even if the reforming catalyst 103 is not heated by a heater or the like, a part of the reforming fuel gas 100a is oxidized and the remaining reforming fuel gas 100a using the heat of the oxidation reaction is used. The decomposition reaction proceeds. The reformed gas 100e containing hydrogen gas generated by the reformer 104 is cooled by the cooler 105 and then supplied to the intake passage 107 (downstream from the throttle valve 106) as fuel for the engine 108. 100b (intake air) is mixed and supplied into the cylinder of the engine 108. The engine 108 generates power by burning the reformed gas 100e containing hydrogen gas in the cylinder.

  When the reforming fuel gas 100a is ammonia gas (nitrogen and hydrogen compound gas), the ammonia gas oxidation reaction (exothermic reaction) is expressed by the following equation (1), and the ammonia gas decomposition reaction (endothermic reaction): ) Is expressed by the following equation (2).

NH ₃ + 3 / 4O ₂ → 1 / 2N ₂ + 3 / 2H ₂ O (1)
NH ₃ → 1 / 2N ₂ + 3 / 2H ₂ (2)

  When the reforming fuel gas 100a is methane gas (hydrocarbon gas), the oxidation reaction (exothermic reaction) of methane gas is expressed by the following equation (3), and the decomposition reaction (endothermic reaction) of methane gas is It is represented by the formula (4). As shown in the equation (4), since water is required for the decomposition reaction of methane gas, it is preferable that the reforming air 100c and water vapor are mixed into the methane gas and then supplied to the reformer 104.

CH ₄ + 2O ₂ → CO ₂ + 2H ₂ O (3)
CH ₄ + 2H ₂ O → 4H ₂ + CO ₂ (4)

  In the reforming system, the supply system for the reforming fuel gas 100a and the reforming air 100c is generally provided with a boosting pump, respectively. On the other hand, when the ejector 101 is used in the metering portion of the reforming fuel gas 100a and the reforming air 100c, the main fluid (the reforming fuel gas 100a) is generated when passing through the orifice 101c of the main flow path 101a. Since the sub-fluid (reforming air 100c) on the side of the sub-flow channel 101b is sucked by the negative pressure, the boosting pump for the sub-fluid (reforming air 100c) supply system becomes unnecessary. Furthermore, by selecting a fuel gas that is filled at a pressure higher than the atmospheric pressure as the reforming fuel supplied to the main channel 101a, the reforming fuel gas 100a is changed using the pressure difference with the fuel tank 109. The ejector 101 can be supplied. This eliminates the need for a pump for boosting the main fluid (reforming fuel gas 100a) supply system. As a result, the reforming system can be miniaturized. In addition, when the reforming fuel gas 100a is a compound gas of nitrogen and hydrogen such as ammonia gas, a water supply system (water tank, evaporator, etc.) required for steam reforming of hydrocarbon gas becomes unnecessary. Further downsizing of the reforming system is possible.

  An intake pressure sensor 113 is provided in the intake passage 107 (downstream of the throttle valve 106) of the engine 108, and the pressure (intake pressure) in the intake passage 107 (downstream of the throttle valve 106) during operation of the engine 108. Is detected by the intake pressure sensor 113. A signal indicating the intake pressure detected by the intake pressure sensor 113 is input to an electronic control unit (ECU) 115. The electronic control unit 115 calculates the required air amount of the ejector 101 based on the intake pressure detected by the intake pressure sensor 113, outputs an air flow control signal, and controls the opening degree of the reforming air control valve 112. . Thereby, the flow rate of reforming air flowing through the air introduction path 111 is controlled, and the flow rate of reforming air sucked into the ejector 101 is controlled.

  Here, the mixing ratio of the reforming air 100c and the reforming fuel gas 100a supplied from the ejector 101 to the reformer 104 (air-fuel ratio Air) with respect to the intake pressure of the engine 108 (pressure downstream of the throttle valve 106). FIG. 2 shows the result of measuring the relationship / Fuel). In FIG. 2, the opening degree of the reforming air control valve 112 is constant. As shown in FIG. 2, it can be seen that the air-fuel ratio Air / Fuel increases as the load on the engine 108 increases (the opening degree of the throttle valve 106 increases) and the intake pressure increases.

  The rate at which the reforming fuel gas 100a is decomposed into hydrogen gas in the reformer 104 (hereinafter referred to as hydrogen generating ability) is greatly affected by the temperature of the reforming catalyst 103. The temperature of the reforming catalyst 103 is determined mainly by the air-fuel ratio Air / Fuel in the reformer 104. Therefore, in order to improve the controllability of the hydrogen generation ability in the reformer 104, the air-fuel ratio Air / Air Fuel controllability is important. However, the adjustment of the reforming air 100c and the reforming fuel gas 100a by the ejector 101 has a large pressure effect, and the load of the engine 108 (the opening degree of the throttle valve 106) changes as shown in FIG. When the pressure changes, the air-fuel ratio Air / Fuel changes. In the reformer 104, when the air-fuel ratio Air / Fuel fluctuates, the rate at which the reforming fuel gas 100a is decomposed into hydrogen gas also fluctuates, and the controllability of the hydrogen generating ability decreases.

  Therefore, in the present embodiment, the reforming air 100c and the reforming fuel gas supplied from the ejector 101 to the reformer 104 with respect to changes in the intake pressure of the engine 108 (pressure downstream of the throttle valve 106). The flow rate of the reforming air sucked into the ejector 101 is controlled by controlling the opening degree of the reforming air control valve 112 so as to suppress the fluctuation of the mixing ratio of 100a (air-fuel ratio Air / Fuel). As shown in FIG. 2, when the load on the engine 108 increases and the intake pressure rises, the air-fuel ratio Air / Fuel increases. Therefore, the reforming air control valve 112 opens with respect to the increase in the intake pressure of the engine 108. By decreasing the degree, an increase in the air-fuel ratio Air / Fuel is suppressed. At that time, the relationship between the intake pressure for maintaining the air-fuel ratio Air / Fuel at a target value (for example, a constant value) and the opening degree of the reforming air control valve 112 with respect to the intake pressure change of the engine 108 is expressed. A characteristic map to be represented (see, for example, characteristic line A in FIG. 3) is created in advance and stored in the storage device of the electronic control unit 115. In the characteristic map shown in the characteristic line A of FIG. 3, the opening degree of the reforming air control valve 112 decreases with an increase in the intake pressure. In this characteristic map, the electronic control unit 115 calculates and controls the opening degree of the reforming air control valve 112 corresponding to the intake pressure detected by the intake pressure sensor 113. Thus, the opening degree of the reforming air control valve 112 is decreased so that the air-fuel ratio Air / Fuel is maintained at a constant target value with respect to the increase in the intake pressure detected by the intake pressure sensor 113.

  According to the present embodiment described above, the variation of the air-fuel ratio Air / Fuel in the reformer 104 from the ejector 101 is controlled by controlling the opening degree of the reforming air control valve 112 according to the intake pressure of the engine 108. Thus, the ratio of the reforming fuel gas 100a reformed to hydrogen gas by the reformer 104 can be set as the target value. As a result, torque fluctuations of the engine 108 due to fluctuations in the hydrogen gas supply amount can be suppressed, and stable operation of the engine 108 can be realized.

“Embodiment 2”
FIG. 4 is a diagram showing a schematic configuration of an engine system according to Embodiment 2 of the present invention. In the following description of the second embodiment, the same or corresponding components as those in the first embodiment are denoted by the same reference numerals, and the components that are not described are the same as those in the first embodiment.

  In the present embodiment, the reforming air control valve 112 includes a valve housing 112c, a movable member 112a, and a spring 112b. The valve housing 112c is formed with an upstream port 112d that communicates with the intake passage 107 via the air introduction path 111 and a downstream port 112e that communicates with the main flow path 101a via the air introduction path 111 and the sub-flow path 101b. ing. The movable member 112a moves in a direction along the central axis (the central axis direction, the vertical direction in FIG. 4) inside the valve housing 112c, thereby changing the opening degree of the reforming air control valve 112. A force toward the downstream port 112e (the lower side in FIG. 4) acts on the movable member 112a due to the pressure of the reforming air 100c from the upstream port 112d, and the upstream port due to the pressing force (elastic force) of the spring 112b. A force to the 112d side (upper side in FIG. 4) acts.

  Due to the negative pressure generated when the reforming fuel gas 100a passes through the orifice 101c of the ejector 101, the movable member 112a is pushed down to the downstream port 112e side (the lower side in FIG. 4). At this time, the balance between the pressing force of the spring 112b and the negative pressure generated in the ejector 101 changes under the influence of the intake pressure of the engine 108 (pressure downstream of the throttle valve 106). Therefore, the position of the movable member 112a in the central axis direction changes according to the intake pressure of the engine 108, and the opening degree of the reforming air control valve 112 changes. When the opening of the throttle valve 106 increases and the intake pressure of the engine 108 increases, the position of the movable member 112a in the central axis direction moves to the downstream port 112e side (lower side in FIG. 4), and the reforming air control valve 112 The degree of opening decreases. Thus, the flow rate of the reforming air sucked into the ejector 101 is adjusted so that the fluctuation of the air-fuel ratio Air / Fuel in the reformer 104 from the ejector 101 is suppressed with respect to the intake pressure change of the engine 108. . At that time, the relationship between the intake pressure and the opening of the reforming air control valve 112 so that the air-fuel ratio Air / Fuel is maintained at a target value (for example, a constant value) with respect to a change in the intake pressure of the engine 108. Is preferably designed (for example, so as to have the relationship shown by the characteristic line A in FIG. 3). Further, it is preferable to design the pressing force of the spring 112b so that the opening degree of the reforming air control valve 112 is not fully closed even under the condition that the throttle valve 106 is fully opened and the intake pressure is highest.

  Also in the present embodiment described above, the variation of the air-fuel ratio Air / Fuel in the reformer 104 from the ejector 101 is adjusted by adjusting the opening degree of the reforming air control valve 112 according to the intake pressure of the engine 108. Thus, the ratio of the reforming fuel gas 100a reformed to hydrogen gas in the reformer 104 can be set as the target value. Furthermore, in this embodiment, since the opening degree of the reforming air control valve 112 mechanically changes with respect to a change in the intake pressure of the engine 108, it is necessary to sequentially detect the intake pressure of the engine 108 with the intake pressure sensor 113. Absent. Therefore, the intake pressure sensor 113 is not required, and the system can be simplified.

“Embodiment 3”
FIG. 5 is a diagram showing a schematic configuration of an engine system according to Embodiment 3 of the present invention. In the following description of the third embodiment, the same or corresponding components as those of the first and second embodiments are denoted by the same reference numerals, and the description of the components that are not described is the same as that of the first and second embodiments.

  In this embodiment, the electronic control unit 115 controls the throttle valve 106 so that the opening degree becomes the target opening degree. Since the intake pressure of the engine 108 (pressure downstream of the throttle valve 106) is dominated by the opening degree of the throttle valve 106, the electronic control unit 115 is linked to the opening degree of the throttle valve 106 and reforming air. By controlling the opening degree of the control valve 112, the fluctuation of the air-fuel ratio Air / Fuel in the reformer 104 from the ejector 101 is suppressed with respect to the change in the opening degree of the throttle valve 106 (intake pressure of the engine 108). In addition, the reforming air flow rate sucked into the ejector 101 is controlled. As shown in FIG. 2, when the opening of the throttle valve 106 increases and the intake pressure rises, the air-fuel ratio Air / Fuel increases. By decreasing the opening degree of the valve 112, an increase in the air-fuel ratio Air / Fuel is suppressed. At that time, the opening degree (target opening degree) of the throttle valve 106 and the reforming purpose for maintaining the air-fuel ratio Air / Fuel at a target value (for example, a constant value) with respect to the change in the opening degree of the throttle valve 106. A characteristic map (see, for example, the characteristic line B in FIG. 6) representing the relationship with the opening degree of the air control valve 112 is created in advance and stored in the storage device of the electronic control unit 115. In the characteristic map shown in the characteristic line B of FIG. 6, the opening degree of the reforming air control valve 112 decreases with an increase in the opening degree (target opening degree) of the throttle valve 106. The electronic control unit 115 calculates and controls the opening degree of the reforming air control valve 112 corresponding to the given opening degree (target opening degree) of the throttle valve 106 in this characteristic map. As a result, the opening degree of the reforming air control valve 112 is decreased so that the air-fuel ratio Air / Fuel is maintained at a constant target value as the opening degree of the throttle valve 106 increases.

  Also in the present embodiment described above, by controlling the opening degree of the reforming air control valve 112 according to the opening degree of the throttle valve 106, the fluctuation of the air-fuel ratio Air / Fuel in the reformer 104 from the ejector 101 is controlled. Thus, the ratio of the reforming fuel gas 100a reformed to hydrogen gas in the reformer 104 can be set as the target value. Furthermore, in this embodiment, the intake pressure sensor 113 that detects the intake pressure of the engine 108 is not necessary, and the system can be simplified.

“Embodiment 4”
FIG. 7 is a diagram showing a schematic configuration of an engine system according to Embodiment 4 of the present invention. In the following description of the fourth embodiment, the same or corresponding components as those of the first to third embodiments are denoted by the same reference numerals, and the description thereof is omitted as in the first to third embodiments.

  In the present embodiment, the reforming air control valve 112 provided in the air introduction path 111 is omitted. A sub-injector 213 serving as a sub fuel gas supply device is provided, and the reforming fuel gas 100a filled in the fuel tank 109 is supplied to the sub injector 213 through the sub fuel gas supply channel 212. . The sub-injector 213 is disposed so as to face the fuel gas flow path 214 between the ejector 101 and the reformer 104, and the reforming fuel gas 100a injected from the sub-injector 213 is supplied to the fuel gas flow path 214, and the ejector 101 is mixed with the primary mixed gas 100f of the reforming fuel gas 100a and the reforming air 100c flowing out from the fuel gas channel 214. The secondary mixed gas 100d of the reforming fuel gas 100a and the reforming air 100c after the mixing is supplied from the fuel gas flow path 214 to the reformer 104. The injection control of the reforming fuel gas 100a from the sub-injector 213 is performed by the electronic control unit 115.

  Further, in the present embodiment, the mixture of the reforming air 100c and the reforming fuel gas 100a supplied to the reformer 104 with respect to changes in the intake pressure of the engine 108 (pressure downstream of the throttle valve 106). The supply amount of the reforming fuel gas 100a from the sub-injector 213 to the reformer 104 is controlled so as to suppress the fluctuation of the ratio (air-fuel ratio Air / Fuel). As shown in FIG. 2, when the opening degree of the throttle valve 106 increases and the intake pressure rises, the air-fuel ratio Air / Fuel increases, so the intake pressure of the engine 108 increases (increase in the opening degree of the throttle valve 106). On the other hand, by increasing the injection amount of the reforming fuel gas 100a from the sub-injector 213 to the reformer 104, an increase in the air-fuel ratio Air / Fuel is suppressed. At that time, a characteristic map (relationship between the intake pressure for maintaining the air-fuel ratio Air / Fuel at a target value (for example, a constant value) and the injection amount of the sub-injector 213 with respect to the intake pressure change of the engine 108 ( For example, the characteristic line C in FIG. 8) is created in advance and stored in the storage device of the electronic control unit 115. In the characteristic map indicated by the characteristic line C in FIG. 8, the injection amount of the sub-injector 213 increases with the increase of the intake pressure. In this characteristic map, the electronic control unit 115 calculates and controls the injection amount of the sub-injector 213 corresponding to the intake pressure detected by the intake pressure sensor 113. Thus, the reforming fuel from the sub-injector 213 to the reformer 104 is maintained so that the air-fuel ratio Air / Fuel is maintained at a constant target value with respect to the increase in the intake pressure detected by the intake pressure sensor 113. The injection amount of the gas 100a is increased. As in the third embodiment, the opening (target opening) of the throttle valve 106 can be used instead of the intake pressure detected by the intake pressure sensor 113.

  In the present embodiment described above, the fluctuation of the air-fuel ratio Air / Fuel in the reformer 104 is controlled by controlling the injection amount of the sub-injector 213 according to the intake pressure of the engine 108 (the opening degree of the throttle valve 106). Thus, the ratio at which the reforming fuel gas 100a is reformed to hydrogen gas in the reformer 104 can be set as the target value.

“Embodiment 5”
FIG. 9 is a diagram showing a schematic configuration of an engine system according to Embodiment 5 of the present invention. In the following description of the fifth embodiment, the same or corresponding components as those in the first to fourth embodiments are denoted by the same reference numerals, and the description thereof is omitted as in the first to fourth embodiments.

  In this embodiment, the reforming air control valve 112 provided in the air introduction path 111 is omitted as compared with the second embodiment. The intake passage 107 of the engine 108 also branches on the upstream side of the throttle valve 106, and the branched sub air introduction passage 117 communicates with the middle portion of the air introduction passage 111, thereby ejecting the ejector via the air introduction passage 111. 101 communicates with the sub-flow channel 101b. The cross-sectional area (flow path area) of the auxiliary air introduction path 117 is sufficiently smaller than the cross-sectional area (flow path area) of the air introduction path 111. Main air 100 g (intake of engine 108) is introduced into the air introduction path 111 from the downstream side of the throttle valve 106 in the intake passage 107, and sub air is introduced into the auxiliary air introduction path 117 from the upstream side of the throttle valve 106 in the intake passage 107. 100h (intake of engine 108) is introduced. The main air 100g and the sub air 100h are mixed in the middle of the air introduction path 111 and introduced into the sub flow path 101b of the ejector 101 as reforming air 100c.

  When the opening of the throttle valve 106 decreases and the intake pressure of the engine 108 (the pressure downstream of the throttle valve 106) decreases, the upstream side of the air introduction path 111 and the intake passage 107 from the throttle valve 106 (atmospheric pressure) And the flow rate of the sub air 100h flowing through the sub air introduction path 117 increases. The flow rate of the main air 100g flowing through the air introduction path 111 decreases with a decrease in the intake pressure. However, by adding the sub air 100h exhibiting the opposite characteristics thereto, the decrease in the reforming air 100c can be reduced. Can be compensated.

  On the other hand, when the opening of the throttle valve 106 increases and the intake pressure of the engine 108 (pressure downstream of the throttle valve 106) increases, the differential pressure before and after the throttle valve 106 in the intake passage 107 becomes smaller, and the sub air The flow rate of the sub air 100h flowing through the introduction path 117 decreases. Since the flow passage area of the sub air introduction path 117 is extremely smaller than the flow passage area of the air introduction path 111, the tube diameter of the sub air introduction path 117 becomes pressure loss under the fully open condition of the throttle valve 106 where the differential pressure becomes zero. Air 100h does not flow. The reforming air 100c is supplied only from the air introduction path 111 having a significantly large pipe diameter.

  As described above, the flow rate ratio between the main air 100g flowing through the air introduction path 111 and the sub air 100h flowing through the sub air introduction path 117 with respect to the change in the intake pressure of the engine 108 (the opening degree of the throttle valve 106). By changing, the reforming air flow rate sucked into the ejector 101 is adjusted so as to suppress the fluctuation of the air-fuel ratio Air / Fuel in the reformer 104 from the ejector 101. As shown in FIG. 2, when the opening degree of the throttle valve 106 is increased and the intake pressure is increased, the air-fuel ratio Air / Fuel is increased, so that the intake pressure is increased (the opening degree of the throttle valve 106 is increased). Since the flow rate of the sub air 100h flowing through the sub air introduction path 117 is decreased, an increase in the air-fuel ratio Air / Fuel is suppressed. At that time, the flow area of the air introduction path 111 and the sub air introduction path 117 may be designed so that the air-fuel ratio Air / Fuel is maintained at a target value (for example, a constant value) with respect to a change in the intake pressure. preferable. Here, the flow rate of the sub air 100h may be controlled more positively by, for example, an ISCV (idle speed control valve) provided with a throttle valve in the middle of the sub air introduction path 117. By optimizing and designing the flow passage area (tube diameter) of the introduction passage 117, the air-fuel ratio Air / Fuel can be metered using only the differential pressure and without control.

  In the present embodiment described above, the flow rate ratio between the main air 100g flowing through the air introduction path 111 and the sub air 100h flowing through the sub air introduction path 117 is set according to the intake pressure of the engine 108 (the opening degree of the throttle valve 106). By adjusting, the fluctuation of the air-fuel ratio Air / Fuel in the reformer 104 from the ejector 101 is suppressed, and the ratio at which the reforming fuel gas 100a is reformed to hydrogen gas by the reformer 104 is set as the target value. be able to. Furthermore, in this embodiment, the intake pressure sensor 113 that detects the intake pressure of the engine 108 is not necessary, and the system can be simplified.

“Embodiment 6”
FIG. 10 is a diagram showing a schematic configuration of an engine system according to Embodiment 6 of the present invention. In the following description of the sixth embodiment, the same or corresponding components as those of the first to fifth embodiments are denoted by the same reference numerals, and the description thereof is omitted as in the first to fifth embodiments.

  In the present embodiment, as compared with the fifth embodiment, one end of the auxiliary air introduction path 117 communicates with air in the atmosphere, and the other end of the auxiliary air introduction path 117 communicates with a middle portion of the air introduction path 111. The sub-flow path 101b of the ejector 101 communicates with the air introduction path 111. The auxiliary air introduction path 117 allows gas to flow from one end (atmosphere side) to the other end (air introduction path 111) and allows gas to flow from the other end (air introduction path 111) to one end (atmosphere side). A check valve 118 is provided to block the flow. Main air 100g (intake of engine 108) is introduced into the air introduction path 111 from the downstream side of the throttle valve 106 in the intake passage 107, and sub air 100h (air in the atmosphere) is introduced into the sub air introduction path 117. . The main air 100g and the sub air 100h are mixed in the middle of the air introduction path 111 and introduced into the sub flow path 101b of the ejector 101 as reforming air 100c. After the system stops, the check valve 118 can prevent the remaining reforming fuel gas 100a from flowing back into the atmosphere.

  In the present embodiment described above as well, as in the fifth embodiment, the main air 100g flowing through the air introduction path 111 and the sub air flowing through the sub air introduction path 117 according to the intake pressure of the engine 108 (the opening degree of the throttle valve 106). By adjusting the flow rate ratio with respect to the air 100h, fluctuations in the air-fuel ratio Air / Fuel from the ejector 101 to the reformer 104 can be suppressed.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, and it can implement with a various form in the range which does not deviate from the summary of this invention. Of course.

  100a reforming fuel gas, 100b air, 100c reforming air, 100d reformed gas, 100e reformed gas, 101 ejector, 101a main channel, 101b subchannel, 101c orifice, 102 injector, 103 reforming catalyst, 104 reform 105, cooler, 106 throttle valve, 107 intake passage, 108 engine, 109 fuel tank, 110 fuel gas supply passage, 111 air introduction passage, 112 reforming air control valve, 112a movable member, 112b spring, 112c valve Housing, 112d upstream port, 112e downstream port, 113 intake pressure sensor, 115 electronic control unit, 117 auxiliary air introduction path, 118 check valve, 212 auxiliary fuel gas supply flow path, 213 sub injector, 214 fuel gas flow path.

Claims (3)

A supply device for supplying a compound gas containing hydrogen;
An ejector including a throttle portion and formed with a main flow path through which the compound gas supplied from a supply device passes, and a sub-flow path that communicates with the main flow path and through which the oxygen-containing gas passes. An ejector capable of mixing the oxygen-containing gas sucked from the sub-flow channel with the compound gas by depressurization at the throttle portion of the compound gas;
By reacting the compound gas mixed with the ejector and the oxygen-containing gas on a catalyst, heat is generated by an oxidation reaction of a part of the compound gas, and the compound gas is decomposed using the generated heat. A reformer that generates hydrogen gas by reaction;
An engine in which the reformed gas generated in the reformer is supplied to the intake passage, and the reformed gas is combusted in a cylinder;
An introduction path for branching from the downstream side of the throttle valve in the intake passage of the engine, communicating with the sub-flow path of the ejector, and introducing the intake air of the engine as an oxygen-containing gas to the ejector;
A mixing ratio that adjusts the amount of oxygen-containing gas drawn into the ejector so as to suppress fluctuations in the mixing ratio of the compound gas and oxygen-containing gas supplied from the ejector to the reformer in response to changes in the intake pressure of the engine An adjustment unit;
Equipped with a,
The mixing ratio adjustment unit branches from the throttle valve upstream of the throttle passage in the intake passage of the engine, communicates with the sub-flow passage of the ejector, and has a sub-introduction passage for introducing the intake air of the engine into the ejector as an oxygen-containing gas. system. A supply device for supplying a compound gas containing hydrogen;
An ejector including a throttle portion and formed with a main flow path through which the compound gas supplied from a supply device passes, and a sub-flow path that communicates with the main flow path and through which the oxygen-containing gas passes. An ejector capable of mixing the oxygen-containing gas sucked from the sub-flow channel with the compound gas by depressurization at the throttle portion of the compound gas;
By reacting the compound gas mixed with the ejector and the oxygen-containing gas on a catalyst, heat is generated by an oxidation reaction of a part of the compound gas, and the compound gas is decomposed using the generated heat. A reformer that generates hydrogen gas by reaction;
An engine in which the reformed gas generated in the reformer is supplied to the intake passage, and the reformed gas is combusted in a cylinder;
An introduction path for branching from the downstream side of the throttle valve in the intake passage of the engine, communicating with the sub-flow path of the ejector, and introducing the intake air of the engine as an oxygen-containing gas to the ejector ;
A mixing ratio that adjusts the amount of oxygen-containing gas drawn into the ejector so as to suppress fluctuations in the mixing ratio of the compound gas and oxygen-containing gas supplied from the ejector to the reformer in response to changes in the intake pressure of the engine An adjustment unit;
With
The mixing ratio adjustment unit includes a sub-introducing path for introducing the atmospheric air into the ejector as the oxygen-containing gas, the engine system. The engine system according to claim 1 or 2 ,
An engine system in which the flow path area of the sub-introduction path is smaller than the flow path area of the introduction path.