JP6269519B2 - Multi-fuel engine fuel control system - Google Patents

Description

  The present invention belongs to a technical field related to a fuel control device for a multi-fuel engine.

  2. Description of the Related Art Conventionally, as shown in, for example, Patent Document 1, there is known a multi-fuel engine in which a plurality of types of fuel are supplied to an engine alone or in combination. In Patent Document 1, a first fuel (for example, alcohol) and a second fuel (for example, gasoline) that is easier to vaporize than the first fuel are supplied to the engine.

JP 2009-047054 A

  By the way, in a multi-fuel engine that can use the first fuel and the second fuel, if a fuel with good ignitability such as hydrogen fuel is used as the first fuel, the lean operation can be performed, and the atmosphere Equivalent emission performance and low fuel consumption can be achieved. However, hydrogen fuel is a fuel that results in insufficient engine output performance and responsiveness. Therefore, it is conceivable to secure the output performance and responsiveness of the engine by using a fuel having a higher calorific value per unit volume than the first fuel as the second fuel. In this case, the second fuel usually has a leaner combustion air-fuel ratio lower than that of the first fuel. From the viewpoint of ensuring emission performance, the second fuel is the same combustion as the first fuel. It is conceivable to use a fuel that emits less NOx from the engine under an air-fuel ratio.

  However, when the first fuel having good ignitability and the second fuel having a leaner combustion air-fuel ratio lower than that of the first fuel are used in combination, compared to the case where the first fuel is used alone, The fuel efficiency will be inferior.

  Therefore, in a situation where only the first fuel can be used, it is preferable to improve the fuel consumption as much as possible by using only the first fuel.

  The present invention has been made in view of such points, and an object of the present invention is to improve fuel efficiency as much as possible in a multi-fuel engine control device while ensuring engine output performance and responsiveness. There is to try.

In order to achieve the above object, the present invention is directed to a fuel control device for a multi-fuel engine mounted on a vehicle and configured to be able to supply a first fuel and a second fuel, respectively. Hydrogen, the second fuel is natural gas, a first fuel injection valve that injects the first fuel to be supplied to the engine, and an injection that supplies the second fuel to the engine. And a control means for controlling the operation of the first and second fuel injection valves, wherein the control means has a load of the engine equal to or higher than a predetermined load, or When the engine output is not constant, the first and second fuels are supplied to the engine at a predetermined ratio and the combustion air-fuel ratio in the combustion chamber of the engine is set to a predetermined first lean air-fuel ratio. 1 and 2 While controlling the fuel injection valve, when the engine is operated at a load lower than the predetermined load and at a constant output, only the first fuel is supplied to the engine and combustion in a combustion chamber of the engine is performed. In order to make the air-fuel ratio higher than the first lean air-fuel ratio, the first fuel single injection control for controlling the first fuel injection valve is executed, and the vehicle is operated by the engine. A generator that is driven to generate power, a battery in which power generated by the generator is charged via a first inverter, and a vehicle drive motor that is supplied with discharge power of the battery via a second inverter; A series hybrid vehicle having generated power supply path through which the power generated by the generator is supplied to the drive motor without passing through the battery, and the efficiency of the engine When the generator can generate the required power of the drive motor without excess or deficiency in engine operation in a high efficiency rotation speed region that is a predetermined value or more, the engine is operated in the high efficiency rotation speed region, The drive motor is supplied with only the electric power generated by the generator through the generated power supply path, and the control means is configured to supply the battery when the battery is not used. When the single fuel single injection control is executed, the combustion air-fuel ratio in the combustion chamber of the engine is higher than the first lean air-fuel ratio and lower than a predetermined value by a predetermined value lower than the lean-limit combustion air-fuel ratio of the first fuel. In order to obtain the second lean air-fuel ratio, the first fuel injection valve is configured to be controlled .

  With the above configuration, when the engine load is equal to or higher than the predetermined load or the engine output is not constant, the first and second fuels are supplied to the engine at a predetermined ratio (for example, approximately the same volume ratio). The combustion air-fuel ratio in the combustion chamber of the engine is set to a predetermined first lean air-fuel ratio. The first lean air-fuel ratio is a lean air-fuel ratio such that the NOx emission amount from the engine is substantially the same as the NOx emission amount when only the second fuel is burned with the lean combustion air-fuel ratio. That's fine. As a result, the output performance and responsiveness of the engine can be secured, and the fuel consumption performance and emission performance are also relatively good. On the other hand, when the engine is operated at a load lower than the predetermined load and at a constant output, only the first fuel is supplied to the engine and the combustion air-fuel ratio in the combustion chamber of the engine is lower than the first lean air-fuel ratio. High (lean) air-fuel ratio. That is, when the engine is operated at a load lower than the predetermined load and at a constant output, there is no problem even if the output performance or responsiveness of the engine is inferior. The fuel efficiency can be improved by making the fuel leaner than the lean air-fuel ratio.

Further, when the battery is not used, the power generated by the generator can be efficiently supplied to the drive motor, and the engine can be operated near the maximum efficiency. The engine output is stabilized by setting the second lean air-fuel ratio, which is the combustion air-fuel ratio when the battery is not used, to the rich side by a predetermined value or more than the lean air-fuel ratio of the first fuel. It is possible to eliminate the engine output fluctuation (particularly the output reduction) and maintain the battery-free supply. In addition, by making the second lean air-fuel ratio as high as possible within a range where the engine output can be stabilized, it is possible to suppress the NOx emission as much as possible, and at the same time, the battery-free supply and the maximum efficiency of the engine By driving, the fuel efficiency can be maximized.

In the fuel control device for the multi-fuel engine , in engine operation in the high-efficiency rotational speed region, when the power generated by the generator is excessive or insufficient with respect to the required power of the drive motor, the engine is The power generated by the generator is supplied to the drive motor via the generated power supply path including the first inverter and the second inverter, and is operated in the rotation speed range, and according to the excess or deficiency. The battery is supplied using the power generated by the generator to be charged to the battery via the first inverter or the discharge power of the battery is supplied to the drive motor via the second inverter, When the first fuel single injection control is executed when the battery is being supplied, the control means controls the engine. The first fuel injection valve is set to a third lean air-fuel ratio that is higher than the second lean air-fuel ratio and lower than the lean-limit combustion air-fuel ratio of the first fuel. It is preferably configured to control.

  As a result, when the battery is used and supplied, the power generated by the generator with respect to the drive motor is generated via the generated power supply path including the first inverter and the second inverter while the engine is operated near the maximum efficiency. However, since the power generated by the generator is excessive or insufficient with respect to the required power of the drive motor, the battery is charged or the discharge power is supplied from the battery to the drive motor according to the excess or shortage. By bringing the third lean air-fuel ratio, which is the combustion air-fuel ratio at this time, close to the lean air-fuel ratio of the first fuel, fuel efficiency and emission performance can be improved as much as possible. Further, when the battery is supplied, even if the engine output is reduced, the discharged electric power of the battery is supplied to the drive motor. Therefore, the third lean air-fuel ratio is set to the lean limit combustion air-fuel ratio of the first fuel. There is no problem even if the engine output becomes unstable.

  In the case of the above configuration, the first fuel tank that stores the first fuel, the second fuel tank that stores the second fuel, and the first fuel that detects the remaining amount of the first fuel in the first fuel tank. And further comprising: a remaining amount detecting means; and a second fuel remaining amount detecting means for detecting a remaining amount of the second fuel in the second fuel tank, wherein the control means is The second remaining amount of the first fuel by the first remaining fuel amount detecting means is less than a first predetermined amount and the remaining amount of the second fuel by the second remaining fuel amount detecting means is greater than the first predetermined amount. When it is equal to or greater than the predetermined amount, it is preferable that the execution of the first fuel single injection control is prohibited.

  That is, the execution of the first fuel single injection control tends to make the consumption amount of the first fuel larger than the consumption amount of the second fuel, and the first fuel tank is emptied earlier than the second fuel tank. There is a possibility that. Therefore, when the battery is being supplied, the first fuel tank is prohibited by executing the first fuel single injection control at a stage where the first fuel is used to some extent with respect to the second fuel. Can be prevented from becoming empty early with respect to the second fuel tank.

  In the case of the above configuration, the control means has a third place where the remaining amount of the first fuel by the first remaining fuel amount detecting means is smaller than the first predetermined amount when the battery is not used. When the second fuel remaining amount by the second fuel remaining amount detecting means is equal to or greater than a fourth predetermined amount that is greater than the third predetermined amount and less than a predetermined amount, execution of the first fuel single injection control is prohibited. It is preferable that it is comprised.

  Thus, when the battery is not supplied until the remaining amount of the first fuel becomes equal to or less than the third predetermined amount which is smaller than the first predetermined amount, that is, until the remaining amount of the first fuel becomes considerably small. The first fuel single injection control is executed. Thereby, fuel consumption performance can be improved as much as possible. The fourth predetermined amount may be, for example, an amount obtained by adding a difference between the first predetermined amount and the second predetermined amount to the third predetermined amount, or may be approximately the same as the second predetermined amount.

In the fuel control apparatus for the multi-fuel engine, the generated power supply path includes a first path through which power generated by the generator is supplied to the drive motor via the first and second inverters, and the generator. The first power single injection control is executed by the control means when the battery is supplied without using the battery and the second path is supplied by bypassing the first and second inverters. When the amplitude and phase of the generated current by the generator substantially match the amplitude and phase of the requested current of the drive motor, respectively, supply of the generated power by the generator to the drive motor is It is preferable that the second route is used.

  In this way, the supply of the generated power by the generator to the drive motor in the battery-free supply is performed by the second path that bypasses the first and second inverters, so that the fuel efficiency can be further improved.

As described above, according to the fuel control device for a multi-fuel engine of the present invention, when the engine load is equal to or higher than a predetermined load or the engine output is not constant, the engine output performance and responsiveness are ensured. In addition, when the engine is operated at a load lower than the predetermined load and at a constant output, only the first fuel is supplied to the engine and the combustion air-fuel ratio in the combustion chamber of the engine is reduced to the first lean air. The fuel efficiency can be improved by the first fuel single injection control in which the air-fuel ratio is higher than the fuel ratio . Further, when the first fuel single injection control is executed when the battery is not being supplied, the combustion air-fuel ratio in the combustion chamber of the engine is set to be higher than the first lean air-fuel ratio and to the first fuel. By setting the second lean air-fuel ratio lower than the lean limit combustion air-fuel ratio by a predetermined value or more, it is possible to suppress the NOx emission amount as much as possible, and to reduce the amount of NOx emission as much as possible and to operate near the maximum efficiency of the engine. , Fuel efficiency can be improved to the maximum.

1 is a schematic view of a vehicle equipped with a multi-fuel engine that is fuel-controlled by a fuel control device according to an embodiment of the present invention. It is a figure which shows the detailed connection relationship of a generator, a battery, a drive motor, a 1st inverter, and a 2nd inverter. It is a block diagram which shows the structure of the engine of the said vehicle, and its control system. It is a graph which shows the relationship between the excess air ratio (lambda) and NOx discharge | emission amount from an engine when making it burn with an engine about hydrogen gas, natural gas, and these mixed gas A, B, and C. FIG. Regarding hydrogen gas, natural gas, and mixed gas A, B, and C thereof, the relationship between the excess air ratio λ and the engine output torque and the excess air ratio λ and the thermal efficiency of the engine when the engine is burned It is a graph which shows a relationship. It is a flowchart which shows a part of process operation at the time of the driving | operation of the engine by a control unit. It is a flowchart which shows the remainder of the processing operation at the time of the engine driving | operation by a control unit.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram of a vehicle 1 equipped with a multi-fuel engine 10 (hereinafter referred to as an engine 10) that is fuel-controlled by a fuel control device according to an embodiment of the present invention. The vehicle 1 is a so-called range extender EV vehicle (also referred to as a vehicle having a series hybrid system (series hybrid vehicle)), and includes an engine 10, a generator 20 driven by the engine 10 to generate electric power, A high-voltage / large-capacity battery 30 in which the power generated by the generator 20 is stored (charged), and the generated power of the generator 20 driven by the engine 10 and the stored power (discharged power) of the battery 30 And a drive motor 40 for driving the vehicle driven by at least one of them. In the present embodiment, the generator 20 is a motor generator having a function of a motor, and the engine 10 is driven (cranked) by the generator 20 as a motor to start the engine 10. .

  A first inverter 50 is provided between the generator 20 and the battery 30, and a second inverter 51 is provided between the battery 30 and the drive motor 40. The 1st inverter 50 and the 2nd inverter 51 are mutually connected, and the battery 30 is connected to the connection line (DC bus line 22 (refer FIG. 2) mentioned later). The electric power generated by the generator 20 is supplied to the battery 30 via the first inverter 50. The discharged power of the battery 30 is supplied to the drive motor 40 via the second inverter 51. Further, in the present embodiment, a generated power supply path 27 is provided in which the power generated by the generator 20 is supplied to the drive motor 40 without going through the battery 30, and the power generated by the generator 20 is generated by the generated power supply path. 27 to the drive motor 40.

  FIG. 2 shows a detailed connection relationship of the generator 20, the battery 30, the drive motor 40, the first inverter 50, and the second inverter 51.

  The generator 20 is connected to the first inverter 50 by a number (three) of connection lines 21 corresponding to the number of phases of the generator 20 (three phases of U, V, and W in this embodiment). The 1 inverter 50 is connected to the battery 30 by two DC bus lines 22 and is also connected to the second inverter 51. A capacitor C1 is connected between the two DC bus lines 22.

  The second inverter 51 is connected to the drive motor 40 by a number (three) of connection lines 23 corresponding to the number of phases of the drive motor 40 (three phases of U, V, and W in this embodiment). In the connection line 21, the first inverter 50, the DC bus line 22, the second inverter 51, and the connection line 23, the electric power generated by the generator 20 is supplied to the drive motor 40 via the first and second inverters 50, 51. The first path 25 is configured.

  In the present embodiment, the generated power supply path 27 includes the first path 25 and a second path 26 provided in parallel with the first path 25 between the generator 20 and the drive motor 40. The second path 26 is a path for supplying the power generated by the generator 20 to the drive motor 40 by bypassing the first and second inverters 50 and 51. In the second path 26, switches 45 to 47 are provided for each phase corresponding to the above phases. These switches 45 to 47 are constituted by semiconductor switches, and are configured such that ON / OFF operations are controlled by a control unit 100 described later. When all of the switches 45 to 47 are turned on, the power generated by the generator 20 is supplied to the drive motor 40 by bypassing the first and second inverters 50 and 51. However, the supply through the second path 26 is performed when the generator 20 can generate the required power of the drive motor 40 without excess or deficiency, and the amplitude and phase of the generated current by the generator 20. Is when the amplitude and phase of the required current of the drive motor 40 substantially coincide with each other.

  The output of the drive motor 40 is transmitted to the drive wheels 61 (the left and right front wheels steered by the steering wheel 62) via the differential device 60, whereby the vehicle 1 travels.

  The engine 10 is a power generation engine used to drive the generator 20 to generate power. The engine 10 uses hydrogen gas stored in a hydrogen tank 70 (corresponding to a first fuel tank) and natural gas (CNG) stored in a CNG tank 71 (corresponding to a second fuel tank) as fuel. It is a multi-fuel engine that can be supplied. In the present embodiment, the hydrogen gas corresponds to the first fuel, and the natural gas corresponds to the second fuel that has a higher calorific value per unit volume and a lower lean combustion air-fuel ratio than the first fuel. . Since hydrogen gas has good ignitability, it is possible to achieve emission performance and low fuel consumption equivalent to the atmosphere by performing lean operation.

  As shown in FIG. 3, the engine 10 is a twin-rotor (two-cylinder) rotary piston engine, and is roughly arranged in a rotor housing chamber 11 a formed in two saddle-shaped rotor housings 11 (inside cylinders). Each of the triangular rotors 12 is accommodated. The two rotor housings 11 are integrated with the side housings so as to be sandwiched between three side housings (not shown), and each rotor housing chamber 11a is composed of each rotor housing 11 and the side housings on both sides thereof. Is formed. In FIG. 3, the two rotor housings 11 (two cylinders) are shown in an unfolded state, and the eccentric shafts 13 drawn at the center portions in the two rotor housings 11 are the same.

  Each of the rotors 12 has apex seals (not shown) at the apexes of the triangles, and the apex seals are in sliding contact with the inner surface of the trochoid of the rotor housing 11. Three working chambers (corresponding to combustion chambers) are defined in 11a (each cylinder). Each rotor 12 rotates around the eccentric shaft 13 in a state where the three apex seals of the rotor 12 are in contact with the inner peripheral surface of the trochoid of the rotor housing 11, and around the axis of the eccentric shaft 13. To revolve around. While the rotor 12 makes one revolution, the working chambers formed between the tops of the rotor 12 move in the circumferential direction, and the intake, compression, expansion (combustion), and exhaust strokes are performed. The rotating force is output from the eccentric shaft 13 as the output shaft through the rotor 12.

  An intake passage 14 is connected to each of the rotor accommodating chambers 11a so as to communicate with an intake opening that opens to the working chamber in the intake stroke, and communicates with an exhaust opening that opens to the working chamber in the exhaust stroke. An exhaust passage 15 is connected to the front. There is one intake passage 14 on the upstream side, but on the downstream side, the intake passage 14 branches into two branch passages and communicates with each of the rotor accommodating chambers 11a. On the upstream side of the branch portion of the intake passage 14 (upstream side of a compressor 85a of an exhaust turbocharger 85 to be described later), the intake passage 14 is driven by a throttle valve actuator 90 such as a stepping motor and has a cross-sectional area ( A throttle valve 16 for adjusting the valve opening) is provided. The throttle valve 16 adjusts the amount of intake air into each rotor accommodating chamber 11a (the working chamber in the intake stroke). In engine control described later in this embodiment, the throttle valve 16 is fully opened.

  Hydrogen ports from which hydrogen gas from the hydrogen tank 70 and natural gas from the CNG tank 71 are respectively injected into the intake passage 14 in each branch passage downstream of the branch portion of the intake passage 14. An injection valve 17A and a CNG port injection valve 17B are provided. The hydrogen gas and natural gas injected by the hydrogen and CNG port injection valves 17A and 17B, respectively, are mixed with air and supplied to the working chamber in the intake stroke. The hydrogen and CNG port injection valves 17A and 17B are used when the engine 10 is extremely cold (the temperature of the engine coolant is considerably low even when the engine is cold). This is a fuel injection valve that is used only at the time of starting at a temperature lower than the lower temperature), and is used for the hydrogen and CNG direct injection valves that will be described later at the time of starting other than extremely cold and during operation of the engine 10. Fuel (hydrogen gas and natural gas) is directly injected into the combustion chamber from 18A and 18B. In other words, when the engine 10 is extremely cold, the fuel injection openings of the hydrogen and CNG direct injection valves 18A and 18B may be blocked by freezing of water generated by fuel combustion. Therefore, fuel is injected from the hydrogen and CNG port injection valves 17A and 17B exceptionally at the time of start-up during extremely cold. When starting and operating the engine 10, fuel is injected only from the hydrogen and CNG port injection valves 17A and 17B, or the hydrogen and CNG direct injection valves 18A and 18B and the hydrogen and CNG are injected. It is also possible to inject fuel from the port injection valves 17A and 17B. Conversely, the hydrogen and CNG port injection valves 17A and 17B can be eliminated. In the following description, it is assumed that fuel (hydrogen gas and natural gas) is injected from the hydrogen and CNG direct injection valves 18A and 18B.

  Two exhaust passages 15 are provided on the upstream side so as to communicate with the respective rotor accommodating chambers 11a, but are joined together on the downstream side. A low temperature active three-way catalyst 81 and a NOx occlusion reduction catalyst 82 for purifying exhaust gas are disposed downstream of the merging portion of the exhaust passage 15. The low temperature active three-way catalyst 81 is a three-way catalyst having a catalyst activation temperature lower than that of the NOx storage reduction catalyst 82, and is disposed upstream of the NOx storage reduction catalyst 82. In FIG. 2, arrows shown in the intake passage 14 and the exhaust passage 15 indicate the flow of intake and exhaust.

  The NOx occlusion reduction catalyst 82 is configured, for example, by supporting a NOx occlusion agent such as barium (Ba) or potassium (K) on a carrier containing a noble metal such as platinum (Pt) or palladium (Pd). The NOx in the exhaust gas of the engine 10 is occluded in a lean air-fuel ratio atmosphere, and the occluded NOx is released in a rich air-fuel ratio atmosphere to cause the NOx to react with HC and CO in the exhaust gas. Have the function of reducing

  In each rotor housing 11 (each cylinder), a hydrogen direct injection valve 18A for directly injecting hydrogen gas from the hydrogen tank 70 into the working chamber (combustion chamber) in the compression stroke of the rotor accommodating chamber 11a; CNG direct injection valve 18B for directly injecting natural gas from the CNG tank 71 into the working chamber (combustion chamber) in the compression stroke of the rotor accommodating chamber 11a, and hydrogen and CNG direct injection valves 18A, 18B Two spark plugs 19 for igniting the injected hydrogen gas and natural gas are provided. Hydrogen gas and natural gas are injected and supplied to the engine 10 (combustion chamber) at substantially the same volume ratio (both are about 50%) except during the first fuel single injection control described later.

  In the present embodiment, the hydrogen direct injection valve 18A corresponds to a first fuel injection valve that injects the first fuel (hydrogen) to the engine 10 and the CNG direct injection valve 18B is a second fuel injection valve. This corresponds to a second fuel injection valve that injects fuel (natural gas) to be supplied to the engine 10.

  The engine 10 is provided with an exhaust turbocharger 85 that supercharges intake air into the working chamber (combustion chamber) in the intake stroke in each rotor accommodating chamber 11a of the engine 10. The exhaust turbocharger 85 includes a compressor 85 a disposed on the downstream side of the throttle valve 16 in the intake passage 14 and a downstream side of the merging portion in the exhaust passage 15 and an upstream side of the three-way catalyst 81. And a turbine 85b disposed in the turbine. The turbine 85b is rotated by the exhaust gas flow, and the rotation of the turbine 85b activates the compressor 85a connected to the turbine 85b to compress the air taken into the intake passage 14. The compressed air is cooled by an intercooler 86 disposed on the downstream side of the compressor 85a in the intake passage 14, and then in the intake chamber in each rotor accommodating chamber 11a via each branch path. Inhaled.

  The vehicle 1 includes a battery current / voltage sensor 101 that detects a current flowing in and out of the battery 30 and a voltage of the battery 30, and an accelerator that detects an amount of depression of an accelerator pedal by an occupant of the vehicle 1 (accelerator opening by an occupant's operation). An opening sensor 102, a vehicle speed sensor 103 that detects the vehicle speed of the vehicle 1, a rotation angle sensor 104 that is provided on the eccentric shaft 13 and detects the rotation angle position of the eccentric shaft 13, and a low-temperature active three-way catalyst in the exhaust passage 15 An air-fuel ratio sensor 105 (configured by a linear O2 sensor in this embodiment) that is disposed between the turbine 81 and the turbine 85 b and detects the air-fuel ratio of the exhaust gas of the engine 10, and the rotor housing 11 It faces the formed water jacket (not shown) and flows through the water jacket. Engine water temperature sensor 106 for detecting the temperature of the engine coolant (engine water temperature), the pressure in the hydrogen tank 70 (that is, the hydrogen gas remaining amount in the hydrogen tank 70), and the pressure in the CHG tank 71 (that is, in the CNG tank 71) A tank pressure sensor 107 (which is provided separately for the hydrogen tank 70 and the CNG tank 71), and an air flow sensor 108 for detecting the intake air flow rate sucked into the intake passage 14. The occupant of the vehicle 1 operates when the vehicle 1 wants to automatically travel the vehicle 1 at a constant speed, the switches 45 to 47 of the second path 26, the operation control of the engine 10, and the first and first 2 Control unit 10 that performs operation control of inverters 50 and 51 (that is, operation control of generator 20 and drive motor 40) Door is provided. The rotation angle sensor 104 also serves as an engine rotation speed sensor that detects the rotation speed of the engine 10. The pressure sensor 107 includes first fuel remaining amount detecting means for detecting the remaining amount of the first fuel (hydrogen gas) in the first fuel tank (hydrogen tank 70), and the first fuel tank (CNG tank 71) in the second fuel tank (CNG tank 71). The second fuel remaining amount detecting means for detecting the remaining amount of the two fuels (natural gas) is configured.

  The control unit 100 is a controller based on a well-known microcomputer, and includes a central processing unit (CPU) that executes a program, a memory that includes, for example, a RAM and a ROM, and stores a program and data; An input / output (I / O) bus. The control unit 100 includes a battery current / voltage sensor 101, an accelerator opening sensor 102, a vehicle speed sensor 103, a rotation angle sensor 104, an air-fuel ratio sensor 105, an engine water temperature sensor 106, a tank pressure sensor 107, an air flow sensor 108, and an auto cruise switch. 56, various information signals from the switches 45 to 47 are input.

  The generator 20 is configured to transmit information on the generated voltage and generated current (including amplitude and phase) by the generator 20 to the control unit 100, and the control unit 100 inputs the information and receives the information. The generated power (power generation amount) by the generator 20 is detected from the above.

  The drive motor 40 transmits information on the rotational speed of the drive motor 40 and information on the regenerative power generation voltage and regenerative power generation current generated by the drive motor 40 to the control unit 100, and the control unit 100 transmits the information. The input is used to control the operation of the drive motor 40.

  Then, based on the input signal, the control unit 100 controls the throttle valve actuator 90, the hydrogen port injection valve 17A, the CNG port injection valve 17B, the hydrogen direct injection valve 18A, the CNG direct injection valve 18B, and A control signal is output to the spark plug 19 to control the engine 10, and a control signal is output to the first and second inverters 50 and 51 to control the generator 20 and the drive motor 40. The control unit 100 constitutes control means for controlling the operation of the hydrogen direct injection valve 18A as the first fuel injection valve and the CNG direct injection valve 18B as the second fuel injection valve. Become.

  The control unit 100 includes a first mode in which only the discharge power of the battery 30 is supplied to the drive motor 40 via the second inverter 51 when the engine 10 is stopped under the control of the first and second inverters 50 and 51. The second mode (battery-free supply) in which only the power generated by the generator 20 is supplied to the drive motor 40, and the power generated by the generator 20 is supplied to the drive motor 40 via the first and second inverters 50 and 51. The power generated by the generator 20 is charged to the battery 30 via the first inverter 50 or the battery 30 depending on whether the power generated by the power generator 20 is excessive or deficient with respect to the power required by the drive motor 40. Is switched to the third mode (battery use supply) in which the discharge power is supplied to the drive motor 40 via the second inverter 51.

  In the present embodiment, in the second mode (battery-free supply), the supply of the generated power by the generator 20 to the drive motor 40 is performed by the first path 25 as described later, The second route 26 may be used. In the third aspect (battery use supply), the generator 20 supplies the generated power to the drive motor 40 only through the first path 25. Note that the second path 26 may be omitted, and the power generated by the generator 20 may be supplied to the drive motor 40 only by the first path 25 even in the second mode (battery-free supply). .

  The control unit 100 detects the remaining capacity (SOC) of the battery 30 based on the current flowing into and out of the battery 30 and the voltage of the battery 30 detected by the battery current / voltage sensor 101.

  When the engine 10 is in a stopped state, the control unit 100 determines whether or not there is an operation request for the engine 10 based on the required output of the drive motor 40 and the SOC value of the battery 30 (in this embodiment, whether or not there is a power generation request). If the engine 10 is requested to operate (power generation request), the engine 10 is cranked by the generator 20 as a motor and the engine 10 is started. The engine 10 is operated to generate power.

  When the engine 10 is operating, the load of the engine 10 is equal to or higher than a predetermined load, or the output of the engine 10 is not constant (for example, when the vehicle 1 is accelerating), the hydrogen gas And natural gas are supplied to the engine 10 at a predetermined ratio (in this embodiment, approximately the same volume ratio as described above), and the combustion air-fuel ratio in the combustion chamber of the engine is set to a predetermined first lean air-fuel ratio (this embodiment). In the embodiment, the hydrogen and CNG direct injection valves 18A and 18B are controlled so that the excess air ratio λ = 1.8). Hereinafter, this control is referred to as normal control.

  In addition, when the engine 10 is operated at a load lower than the predetermined load and at a constant output, the control unit 100 supplies only hydrogen gas to the engine 10 and the combustion air-fuel ratio in the combustion chamber of the engine 10 In order to make the air / fuel ratio higher than the first lean air / fuel ratio, the first fuel single injection control for controlling the hydrogen direct injection valve 18A is executed. In the present embodiment, when the auto-cruise switch 56 is operated and turned on by an occupant of the vehicle 1, the engine 10 is operated with a load lower than the predetermined load and a constant output. While the single fuel injection control is executed, when the auto cruise switch 56 is OFF, the normal control is executed on the assumption that the load of the engine 10 is equal to or higher than the predetermined load or the output of the engine 10 is not constant. ing.

  In the present embodiment, the control unit 100 operates when the generator 20 can generate the required power of the drive motor 40 without excess or deficiency during engine operation in a high-efficiency rotational speed region where the efficiency of the engine 10 is a predetermined value or more. The engine 10 is operated in the high-efficiency rotational speed region, and only the power generated by the generator 20 is supplied to the drive motor 40 via the generated power supply path 27 (the first path 25 or the second path 26). The battery non-use supply is executed. The high-efficiency rotational speed region is a high-efficiency region (for example, 1800 rpm to 2200 rpm) including the highest efficiency point of the engine 10.

  Further, the control unit 100 operates the engine 10 in the high-efficiency rotational speed region when the power generated by the generator 20 is excessive or insufficient with respect to the required power of the drive motor 40. While operating in several regions, the power generated by the generator 20 is supplied to the drive motor 40 via the generated power supply path 27 (that is, the first path 25) including the first and second inverters 50 and 51. In response to the excess or deficiency, the battery 30 supplies the power generated by the generator 20 to the battery 30 via the first inverter 50 or supplies the discharge power of the battery 30 to the drive motor 40 via the second inverter 51. Execute usage supply.

  When the control unit 100 executes the first fuel single injection control when the battery-free supply is executed, the control unit 100 sets the combustion air-fuel ratio in the combustion chamber of the engine 10 to be higher than the first lean air-fuel ratio. The direct injection valve 18A for hydrogen is controlled so that the second lean air-fuel ratio (λ = 2.2 in this embodiment) is lower than the combustion air-fuel ratio at the lean limit of hydrogen gas by a predetermined value or more.

  In addition, when the control unit 100 executes the first fuel single injection control when the battery non-use supply is performed, the amplitude and phase of the generated current by the generator 20 are the amplitude and phase of the requested current of the drive motor 40. Are substantially coincident with each other, the power generated by the generator 10 is supplied to the drive motor 40 through the second path 26. On the other hand, when the control unit 100 executes the first fuel single injection control when the battery non-use supply is executed, the control unit 100 substantially matches the amplitude of the generated current by the generator 20 with the amplitude of the requested current of the drive motor 40. If the phase of the generated current by the generator 20 does not substantially match the phase of the requested current of the drive motor 40, supply of the generated power by the generator 10 to the drive motor 40 is performed as described above. The first route 26 is used. The control unit 100 supplies the power generated by the generator 10 to the drive motor 40 through the first path 26 when the normal control is executed when the battery-free supply is executed.

  Further, when the control unit 100 executes the first fuel single injection control at the time of the battery use supply, the control unit 100 sets the combustion air-fuel ratio in the combustion chamber of the engine 10 to be higher than the second lean air-fuel ratio and to the hydrogen The hydrogen direct injection valve 18A is controlled so that the third lean air-fuel ratio (λ = 2.6 in the present embodiment) is lower than the gas lean limit combustion air-fuel ratio. When the control unit 100 executes the first fuel single injection control when the battery use supply is executed, the control unit 100 supplies the power generated by the generator 10 to the drive motor 40 through the first path 26. The control unit 100 also supplies the generated power from the generator 10 to the drive motor 40 via the first path 26 when executing the normal control when the battery use supply is executed.

  Here, FIG. 4 shows the excess air ratio λ and the engine 10 when hydrogen gas, natural gas, and mixed gas A, B, C thereof are burned by the engine 10 (rotation speed 2000 rpm, throttle valve 16 fully opened). The relationship with the NOx emission amount from (combustion chamber) is shown. The mixed gas A has hydrogen gas and natural gas at substantially the same volume ratio (both are about 50%), and the mixed gas B has a larger volume ratio of hydrogen gas than the mixed gas A, The mixed gas C has a volume ratio of hydrogen gas larger than that of the mixed gas B. FIG. 5 shows the relationship between the excess air ratio λ and the output torque of the engine 10 when the above-mentioned gases shown in FIG. 4 are burned by the engine 10 (rotation speed 2000 rpm, throttle valve 16 fully opened), and air. The relationship between excess ratio (lambda) and the thermal efficiency of the engine 10 is shown. Here, natural gas is injected from the CNG direct injection valve 18B, and hydrogen gas is injected from the hydrogen port injection valve 17A. In this case, compared with the case where hydrogen gas and natural gas are respectively injected from the hydrogen and CNG direct injection valves 18A and 18B, the magnitude of the output torque and the like change, but the tendency of the above relationship does not change greatly.

  From FIG. 4 and FIG. 5, the lean air limit combustion air-fuel ratio (here, excess air ratio λ) of natural gas is 1.6, and even if the excess air ratio λ is larger than this, stable ignition is achieved. I can't do it. 4 and 5, the excess air ratio λ is only up to 2.7, but the lean excess air excess ratio λ of hydrogen gas is about 3. In FIGS. 3 and 4, the results when the excess air ratio λ of hydrogen gas is lower than 1.8 are omitted.

  As shown in FIG. 4, if the excess air ratio λ is the same, the natural gas has a smaller NOx emission than the hydrogen gas, and the mixed gas A, B, C has a larger volume ratio of the natural gas (hydrogen gas It can be seen that the smaller the volume ratio), the smaller the NOx emissions. That is, when the volume ratio of hydrogen gas in the hydrogen gas or mixed gas is large, the NOx emission amount increases. However, when the volume ratio of hydrogen gas in the hydrogen gas or mixed gas is large, the lean combustion air-fuel ratio becomes high, so the NOx emission can be reduced by increasing the combustion air-fuel ratio in the combustion chamber. .

  In the present embodiment, the first lean air-fuel ratio that is the combustion air-fuel ratio when the load of the engine 10 is equal to or greater than the predetermined load or the output of the engine 10 is not constant is λ = 1.8. The NOx emission amount is the NOx emission amount at the point Q1 on the mixed gas A line in FIG. 4, and the output torque of the engine 10 is the output torque at the point Q1 ′ on the mixed gas A line in FIG. . The NOx emission amount at point Q1 is substantially the same as the NOx emission amount (point P on the natural gas only line) when only natural gas is burned with its lean limit combustion air-fuel ratio (λ = 1.6). (Slightly more).

  Further, since the second lean air-fuel ratio, which is the combustion air-fuel ratio when the first fuel single injection control is executed when the battery-free supply is executed, is λ = 2.2, the NOx emission amount at this time is 4, the NOx emission amount at the point Q2 on the hydrogen gas line is obtained, and the output torque of the engine 10 is the output torque at the point Q2 ′ on the hydrogen gas line in FIG. 5.

  Further, since the third lean air-fuel ratio, which is the combustion air-fuel ratio at the time of executing the first fuel single injection control at the time of executing the battery use supply, is λ = 2.6, the NOx emission amount at this time is In FIG. 4, the NOx emission amount at the point Q3 on the hydrogen gas line becomes the output torque of the engine 10, and the output torque of the engine 10 becomes the output torque at the point Q3 'on the hydrogen gas line in FIG.

  It can be said that the NOx emission amount at the Q2 point and the Q3 point is substantially the same as the NOx emission amount at the Q1 point (the NOx emission amount at the Q2 point is slightly larger than the NOx emission amount at the Q1 point and the Q3 point).

  Further, although the output torque at the point Q2 ′ is lower than the output torque at the point Q1 ′, there is no problem because the engine is operated with a load lower than a predetermined load and a constant output. By setting the second lean air-fuel ratio to an air-fuel ratio that is higher than the first lean air-fuel ratio and lower than the combustion air-fuel ratio (λ = 3) of the lean limit of hydrogen gas by a predetermined value or more, the output of the engine 10 is increased. It is possible to stabilize the output, and it is possible to eliminate the output fluctuation (especially a decrease in output) of the engine 10 and maintain the battery-free supply. In this non-battery supply, combined with the operation near the maximum efficiency of the engine 10, the fuel efficiency can be maximized. In particular, when the power generated by the generator 10 is supplied to the drive motor 40 by the second path 26, the fuel efficiency can be further improved.

  The output torque at the point Q3 ′ becomes lower than the output torque at the point Q2 ′, and the third air-fuel ratio becomes an air-fuel ratio close to the combustion air-fuel ratio at the lean limit of hydrogen gas. However, when the battery supply is being performed, the discharge power of the battery 30 is supplied to the drive motor 40 even if the output of the engine 10 is reduced. Therefore, the third lean air-fuel ratio is reduced to the lean amount of the first fuel. There is no problem even if the output of the engine 10 becomes unstable near the limit combustion air-fuel ratio. On the other hand, fuel efficiency performance and emission performance can be improved as much as possible by bringing the third lean air-fuel ratio close to the lean air-fuel ratio of the first fuel in this way.

  In the present embodiment, the control unit 100 prohibits the execution of the first fuel single injection control according to the remaining amounts of hydrogen gas and natural gas by the tank pressure sensor 107. More specifically, when the first condition relating to the remaining amount of hydrogen gas and natural gas by the tank pressure sensor 107 is satisfied during execution of the battery use supply, the execution of the first fuel single injection control is prohibited. The first condition is a condition that the remaining amount of hydrogen gas is not more than a first predetermined amount and the remaining amount of natural gas is not less than a second predetermined amount that is larger than the first predetermined amount.

  That is, due to the execution of the first fuel single injection control, the hydrogen gas consumption tends to be larger than the natural gas consumption, and the hydrogen tank 70 may be emptied earlier than the CNG tank 71. There is sex. Therefore, when the battery is used and supplied, when the hydrogen gas is used to some extent relative to the natural gas, the execution of the first fuel single injection control is prohibited, so that the hydrogen tank 70 This prevents the CNG tank 71 from being emptied early.

  Further, the control unit 100 executes the first fuel single injection control when the second condition regarding the remaining amount of hydrogen gas and natural gas by the tank pressure sensor 107 is satisfied when the battery non-use supply is performed. Ban. The second condition is that the remaining amount of hydrogen gas is not more than a third predetermined amount that is less than the first predetermined amount, and the remaining amount of natural gas is not less than a fourth predetermined amount that is greater than the third predetermined amount. This is the condition. The fourth predetermined amount may be, for example, an amount obtained by adding a difference between the first predetermined amount and the second predetermined amount to the third predetermined amount, or may be substantially the same amount as the second predetermined amount. Also good. As a result, until the remaining amount of hydrogen gas becomes equal to or less than a third predetermined amount that is smaller than the first predetermined amount, that is, until the remaining amount of hydrogen gas is considerably reduced, the second time when the battery is not supplied is The single fuel single injection control is executed, whereby the fuel efficiency can be improved as much as possible.

  Next, processing operations when the engine 10 is operated by the control unit 100 will be described based on the flowcharts of FIGS. 6 and 7.

  In the first step S1, signals from various sensors are read, and in the next step S2, the required output of the drive motor 40 is calculated based on the signals from the accelerator opening sensor 102 and the vehicle speed sensor 103.

  In the next step S3, the required power (required voltage and required current (including amplitude and phase)) of the drive motor 40 is calculated based on the required output of the drive motor 40. In the next step S4, the auto cruise switch 56 is calculated. It is determined whether or not is ON.

  When the determination in step S4 is NO, the process proceeds to step S16. On the other hand, when the determination in step S4 is YES, the process proceeds to step S5, and the generator 20 is operated in the operation in the high-efficiency rotation speed region of the engine 10. Determines whether the required power of the drive motor 40 can be generated without excess or deficiency.

  If the determination in step S5 is NO, the process proceeds to step S11. If the determination in step S5 is YES, the process proceeds to step S6, and whether the second condition regarding the remaining amount of hydrogen gas and natural gas is satisfied. (Whether the remaining amount of hydrogen gas is not more than the third predetermined amount and the remaining amount of natural gas is not less than the fourth predetermined amount).

  When the determination in step S6 is YES, the process proceeds to step S17. When the determination in step S6 is NO, the process proceeds to step S7, and the amplitude and phase of the power generation current generated by the generator 20 is determined by the request of the drive motor 40. It is determined whether or not the current amplitude and phase substantially coincide with each other.

  When the determination in step S7 is YES, the process proceeds to step S8 where only hydrogen gas is supplied to the engine 10 and the combustion air-fuel ratio in the combustion chamber of the engine 10 is set to the first lean air-fuel ratio (λ = 1.8). ), The first fuel single injection control is performed so that the air-fuel ratio is higher (here, λ = 2.2). In addition, the engine 10 is operated in the high-efficiency rotation speed region, and the battery-free supply in which only the power generated by the generator 20 is supplied to the drive motor 40 via the second path 26 is executed. Thereafter, the process proceeds to step S10.

  When the determination in step S7 is NO, the process proceeds to step S9 where only hydrogen gas is supplied to the engine 10 and the combustion air-fuel ratio in the combustion chamber of the engine 10 is set to the first lean air-fuel ratio (λ = 1.8). ), The first fuel single injection control is performed so that the air-fuel ratio is higher (here, λ = 2.2). Further, the engine 10 is operated in the high-efficiency rotational speed region, and the battery-free supply in which only the power generated by the generator 20 is supplied to the drive motor 40 via the first path 25 is executed. Thereafter, the process proceeds to step S10.

  In step S10, the fuel injection amount is calculated based on the required output of the engine 10, the intake air amount, the engine speed, and the target air-fuel ratio, and then the process returns.

  In step S11 that proceeds when the determination in step S5 is NO, whether or not the first condition regarding the remaining amount of hydrogen gas and natural gas is satisfied (the remaining amount of hydrogen gas is equal to or less than the first predetermined amount and It is determined whether or not the remaining amount of natural gas is equal to or greater than the second predetermined amount.

  If the determination in step S11 is YES, the process proceeds to step S21. If the determination in step S11 is NO, the process proceeds to step S12, and the power generated by the generator 20 is excessive with respect to the required power of the drive motor 40. It is determined whether or not.

  When the determination in step S12 is YES, the process proceeds to step S13, and it is determined whether or not the SOC of the battery 30 is lower than a preset upper limit threshold value. The upper limit threshold is a value that accelerates the deterioration of the battery 30 when the battery 30 is charged more than this. If the determination in step S13 is NO, the process proceeds to step S22. If the determination in step S13 is YES, the process proceeds to step S15.

  When the determination in step S12 is NO, the process proceeds to step S14, and it is determined whether or not the SOC of the battery 30 is higher than a preset lower limit threshold value. This lower limit threshold is a value that accelerates the deterioration of the battery 30 when the SOC becomes lower than this, and is a value that needs to be charged early in order to drive the drive motor 40 by the discharged power of the battery 30.

  When the determination in step S14 is NO, the process proceeds to step S23, while when the determination in step S14 is YES, the process proceeds to step S15.

  In step S15, only hydrogen gas is supplied to the engine 10, and the combustion air-fuel ratio in the combustion chamber of the engine 10 is higher than the first lean air-fuel ratio (λ = 1.8) (here, in step S8). , The first fuel single injection control is executed to make the air fuel ratio (λ = 2.6) higher than the air fuel ratio at the time of the first fuel single injection control in S9. In addition, the engine 10 is operated in the high-efficiency rotational speed region, and the power generated by the generator 20 is supplied to the drive motor 40, and the power generated by the generator 20 is excessive or insufficient with respect to the required power of the drive motor 40. In response, the battery 30 is supplied by using the power generated by the generator 20 to charge the battery 30 via the first inverter 50 or supplying the discharged power from the battery 30 to the drive motor 40 via the second inverter 51. Thereafter, the process proceeds to step S10.

  In step S16 that proceeds when the determination in step S4 is NO, whether the generator 20 can generate the required power of the drive motor 40 without excess or deficiency in the operation of the engine 10 in the high-efficiency rotational speed region. Determine whether or not.

  When the determination in step S16 is NO, the process proceeds to step S18. When the determination in step S16 is YES, the process proceeds to step S17.

  In step S17, hydrogen gas and natural gas are supplied to the engine 10 at a predetermined ratio (here, approximately 50%), and the combustion air-fuel ratio in the combustion chamber of the engine 10 is set to the first lean air-fuel ratio (here Then, the above-described normal control is performed so that λ = 1.8). Further, the engine 10 is operated in the high-efficiency rotational speed region, and the battery-free supply in which only the power generated by the generator 20 is supplied to the drive motor 40 via the first path 25 is executed. Thereafter, the process proceeds to step S10.

  In step S <b> 18, it is determined whether the power generated by the generator 20 is excessive with respect to the required power of the drive motor 40. When the determination at step S18 is YES, the process proceeds to step S19, while when the determination at step S18 is NO, the process proceeds to step S20.

  In step S19, it is determined whether or not the SOC of the battery 30 is lower than the upper limit threshold value. When the determination in step S19 is NO, the process proceeds to step S22, while when the determination in step S19 is YES, Proceed to step S21.

  In step S20, it is determined whether or not the SOC of the battery 30 is higher than the lower limit threshold value. When the determination in step S20 is YES, the process proceeds to step S21, while when the determination in step S20 is NO, Proceed to step S23.

  In step S21, hydrogen gas and natural gas are supplied to the engine 10 at a predetermined ratio (here, approximately 50% in both cases), and the combustion air-fuel ratio in the combustion chamber of the engine 10 is set to the first lean air-fuel ratio (λ = 1.8) The normal control is executed. In addition, the engine 10 is operated in the high-efficiency rotational speed region, and the power generated by the generator 20 is supplied to the drive motor 40, and the power generated by the generator 20 is excessive or insufficient with respect to the required power of the drive motor 40. In response, the battery 30 is supplied by using the power generated by the generator 20 to charge the battery 30 via the first inverter 50 or supplying the discharged power from the battery 30 to the drive motor 40 via the second inverter 51. Thereafter, the process proceeds to step S10.

  In step S <b> 22, the engine 10 is stopped and the drive motor 40 is driven only by the discharged power of the battery 30. Thereafter, the process proceeds to step S10.

  In step S23, hydrogen gas and natural gas are supplied to the engine 10 at a predetermined ratio (here, approximately 50% in both cases), and the combustion air-fuel ratio in the combustion chamber of the engine 10 is set to the first lean air-fuel ratio (λ = 1.8) The normal control is executed. Further, the generator 20 operates the engine 10 on the higher rotation side than the high-efficiency rotation speed region so as to generate electric power for charging the battery 30 in addition to the required electric power of the drive motor 40. Thereafter, the process proceeds to step S10.

  Therefore, in the present embodiment, when the load of the engine 10 is equal to or higher than the predetermined load or the output of the engine 10 is not constant, the hydrogen gas and the natural gas are mixed at a predetermined ratio (in this embodiment, substantially the same volume ratio). Accordingly, the normal output of the engine 10 to the engine 10 and the combustion air-fuel ratio in the combustion chamber of the engine 10 to a predetermined first lean air-fuel ratio (λ = 1.8 in the present embodiment) is controlled. Responsiveness can be ensured. Further, when the engine 10 is operated at a load lower than the predetermined load and at a constant output, only hydrogen gas is supplied to the engine 10 and the combustion air-fuel ratio in the combustion chamber of the engine 10 is set to the first lean. The fuel efficiency can be improved by the first fuel single injection control in which the air-fuel ratio is higher than the air-fuel ratio (λ = 2.2 or λ = 2.6 in the present embodiment).

  In addition, when the first fuel single injection control is executed when the battery is not supplied, the combustion air-fuel ratio in the combustion chamber of the engine 10 is set higher than the first lean air-fuel ratio and hydrogen gas. Since the second lean air-fuel ratio (λ = 2.2) lower than the lean limit combustion air-fuel ratio by a predetermined value or more is achieved, the output of the engine 10 can be stabilized, and the output fluctuation of the engine 10 (particularly, The above-mentioned battery non-use supply can be maintained by eliminating (output reduction). Further, by making the second lean air-fuel ratio as high as possible within a range where the output of the engine 10 can be stabilized, the NOx emission amount can be suppressed as much as possible, and the battery-free supply and the vicinity of the maximum efficiency of the engine By driving with, fuel efficiency can be maximized.

  Further, when the first fuel single injection control is executed while the battery is being supplied, the combustion air-fuel ratio in the combustion chamber of the engine 10 is set higher than the second lean air-fuel ratio and the hydrogen gas Since the third lean air-fuel ratio (λ = 2.6) lower than the lean-limit combustion air-fuel ratio is set, the third lean air-fuel ratio is brought close to the lean-limit combustion air-fuel ratio of hydrogen gas to improve fuel efficiency. In addition, the emission performance can be improved as much as possible. Further, when the battery is used and supplied, the discharge power of the battery 10 is supplied to the drive motor 40 even if the output of the engine 10 is reduced. Therefore, the third lean air-fuel ratio is burned at the lean limit of hydrogen gas. There is no problem even if the output of the engine 10 becomes unstable near the air-fuel ratio.

  Further, when the first fuel single injection control is executed when the battery is not used and supplied, the amplitude and phase of the generated current by the generator 20 are the same as the amplitude and phase of the requested current of the drive motor 40. When they substantially coincide with each other, the supply of the generated power by the generator 20 to the drive motor 40 in the battery-free supply is performed by the second path 26 that bypasses the first and second inverters 50 and 51, so that the fuel consumption performance Can be further improved.

  The present invention is not limited to the embodiment described above, and can be substituted without departing from the spirit of the claims.

For example, in the above embodiment, the engine 10 and the rotary piston engine, it is also possible to reciprocating engines.

  The above-described embodiments are merely examples, and the scope of the present invention should not be interpreted in a limited manner. The scope of the present invention is defined by the scope of the claims, and all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  The present invention is useful for a fuel control device of a multi-fuel engine that is mounted on a vehicle and configured to be able to supply a first fuel and a second fuel, respectively.

DESCRIPTION OF SYMBOLS 1 Vehicle 10 Various fuel engine 18A Direct injection valve for hydrogen (1st fuel injection valve)
18B CNG direct injection valve (second fuel injection valve)
20 generator 25 first path 26 second path 27 generated power supply path 30 battery 40 drive motor 50 first inverter 51 second inverter 70 hydrogen tank (first fuel tank)
71 CNG tank (second fuel tank)
100 Control unit (control means)
107 Tank pressure sensor (first fuel remaining amount detecting means) (second fuel remaining amount detecting means)

Claims (5)

A fuel control device for a multi-fuel engine mounted on a vehicle and configured to be able to supply a first fuel and a second fuel, respectively,
The first fuel is hydrogen;
The second fuel is natural gas,
A first fuel injection valve for injecting the first fuel to be supplied to the engine;
A second fuel injection valve for injecting the second fuel to be supplied to the engine;
Control means for controlling the operation of the first and second fuel injection valves,
The control means includes
When the engine load is equal to or higher than the predetermined load or the engine output is not constant, the first and second fuels are supplied to the engine at a predetermined ratio and the combustion air in the combustion chamber of the engine is supplied. While controlling the first and second fuel injection valves so that the fuel ratio becomes a predetermined first lean air-fuel ratio,
When the engine is operated at a load lower than the predetermined load and at a constant output, only the first fuel is supplied to the engine and the combustion air-fuel ratio in the combustion chamber of the engine is set to the first lean air In order to make the air-fuel ratio higher than the fuel ratio, the first fuel single injection control for controlling the first fuel injection valve is executed ,
The vehicle is driven by the engine to generate power, a battery in which power generated by the power generator is charged via a first inverter, and discharge power of the battery is supplied via a second inverter. A series hybrid vehicle having a drive motor for driving the vehicle and a generated power supply path through which the power generated by the generator is supplied to the drive motor without passing through the battery;
When the generator is capable of generating the required power of the drive motor without excess or deficiency in engine operation in a high efficiency rotational speed region where the engine efficiency is equal to or greater than a predetermined value, the engine is in the high efficiency rotational speed region. The battery is used without being supplied to the drive motor, and only the power generated by the generator is supplied to the drive motor via the generated power supply path.
Further, the control means sets the combustion air-fuel ratio in the combustion chamber of the engine to be higher than the first lean air-fuel ratio when executing the first fuel single injection control when the battery is not used. Various fuels configured to control the first fuel injection valve so as to have a second lean air-fuel ratio that is high and lower than a combustion air-fuel ratio at a lean limit of the first fuel by a predetermined value or more. Engine fuel control device. The fuel control apparatus for a multi-fuel engine according to claim 1 ,
In engine operation in the high-efficiency rotational speed region, when the power generated by the generator is excessive or insufficient with respect to the required power of the drive motor, the engine is operated in the high-efficient rotational speed region and the drive is performed. The electric power generated by the generator is supplied to the motor via the generated electric power supply path including the first inverter and the second inverter, and the electric power generated by the generator is changed according to the excess or deficiency. The battery is supplied to be charged to the battery via one inverter, or the discharge power of the battery is supplied to the drive motor via the second inverter,
When performing the first fuel single injection control when the battery is being supplied, the control means sets the combustion air-fuel ratio in the combustion chamber of the engine to be higher than the second lean air-fuel ratio and A fuel control apparatus for a multi-fuel engine, characterized in that the first fuel injection valve is controlled so as to have a third lean air-fuel ratio lower than the lean limit combustion air-fuel ratio of the first fuel. . The fuel control apparatus for a multi-fuel engine according to claim 2 ,
A first fuel tank for storing the first fuel;
A second fuel tank for storing the second fuel;
First fuel remaining amount detecting means for detecting the remaining amount of the first fuel in the first fuel tank;
A second fuel remaining amount detecting means for detecting a remaining amount of the second fuel in the second fuel tank;
The control means is configured such that when the battery is used and supplied, the remaining amount of the first fuel by the first fuel remaining amount detecting means is less than a first predetermined amount and the second fuel remaining amount detecting means performs the second The multi-fuel engine is configured to prohibit the execution of the first fuel single injection control when the remaining amount of fuel is equal to or greater than a second predetermined amount greater than the first predetermined amount. Fuel control device. The fuel control apparatus for a multi-fuel engine according to claim 3 ,
The control means is configured such that when the battery is not being supplied, the remaining amount of the first fuel by the first fuel remaining amount detecting means is less than a third predetermined amount that is less than the first predetermined amount and the When the remaining amount of the second fuel by the second remaining fuel amount detecting means is not less than a fourth predetermined amount that is larger than the third predetermined amount, the execution of the first fuel single injection control is prohibited. A fuel control apparatus for a multi-fuel engine characterized by the above. The fuel control apparatus for a multi-fuel engine according to any one of claims 1 to 4 ,
The generated power supply path includes a first path through which the power generated by the generator is supplied to the drive motor via the first and second inverters, and the power generated by the generator is the first and second 2 consisting of a second path supplied by bypassing the inverter,
When the first fuel single injection control is executed by the control means when the battery is not used and supplied, the amplitude and phase of the generated current by the generator are the amplitude of the required current of the drive motor and A fuel control device for a multi-fuel engine, wherein when the phases substantially coincide with each other, supply of electric power generated by the generator to the drive motor is performed by the second path.

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