JP4737028B2 - Dual fuel engine controller - Google Patents

Description

  The present invention belongs to a technical field related to a control device for a dual fuel engine that can be driven by selectively switching two used fuels.

  2. Description of the Related Art Conventionally, there is known a dual fuel engine in which the fuel used can be selectively switched between gasoline (first fuel) and gaseous fuel (second fuel) (see, for example, Patent Document 1). The engine) has a catalyst in the exhaust passage for purifying harmful substances such as HC and NOx generated in the combustion process of the fuel used.

  Here, when the engine is operated using the gaseous fuel as a fuel to be used, harmful substances (hereinafter referred to as exhaust emission) contained in the exhaust gas after passing through the catalyst are in an inactive state when the catalyst is in an inactive state. Compared to the case where gasoline is used as fuel, the engine is in an inactive state because the temperature of the engine is lower than the activation temperature at the time of cold start such as immediately after engine start. In some cases, the gaseous fuel is used as fuel, while the catalyst is heated to reach an activation temperature as the engine warms up and when activated, the gasoline is used as fuel. It is configured as follows.

Therefore, whenever the catalyst is in an inactive state, it is possible to use gaseous fuel that uses less exhaust emissions in the inactive state than gasoline, thereby reducing exhaust emissions and realizing a clean engine. is doing.
JP 2000-213394 A

  By the way, in a vehicle equipped with a dual fuel engine as described above, due to the difference in chemical properties between the first fuel and the second fuel, the fuel consumption of the vehicle and the engine The output torque (hereinafter referred to as engine torque) may be different. For this reason, there is a demand to select the fuel to be used by the occupant himself according to the traveling state desired by the occupant, such as a traveling state emphasizing fuel efficiency and a traveling state emphasizing torque.

  In order to meet such demands, for example, a fuel changeover switch (fuel selection means) that can be operated by the occupant is provided in advance, and the occupant can select the fuel to be used by operating the fuel changeover switch. It is possible to do. In this case, in addition to the fuel selection condition for selecting the fuel to be used based on the active state of the catalyst (hereinafter referred to as the first fuel selection condition), the passenger's intention determined by operating the fuel changeover switch. It is necessary to further add a fuel selection condition based on (hereinafter referred to as a second fuel selection condition).

  However, when such a second fuel selection condition based on the passenger's intention is simply added, there is a problem that the two conditions, the first fuel selection condition and the second fuel selection condition, interfere with each other. That is, for example, when the second fuel is selected as the use fuel based on the first fuel selection condition, and when the first fuel is selected as the use fuel based on the second fuel selection condition, There is a problem as to which of the first fuel and the second fuel is used.

  The present invention has been made in view of such points, and an object of the present invention is to use a first fuel and a second fuel with less exhaust emission when the catalyst is inactive than the first fuel as the fuel used. In a dual-fuel engine that can be switched between, and when a vehicle occupant equipped with the engine has a fuel selection means for selecting a fuel to be used, the catalyst is activated to reduce the exhaust emission. An object of the present invention is to make it possible to select an appropriate fuel to be used by preventing interference between the fuel selection condition based on the fuel selection condition based on the intention of the occupant for enabling the traveling state desired by the occupant.

In order to achieve the above object, the present invention comprises fuel selection means capable of selecting one of the first fuel and the second fuel by the operation of the occupant, and the fuel selection means when the catalyst is in an inactive state. When the second fuel is used as fuel to be used regardless of the fuel selected by the above, and the second fuel is used as the fuel because the catalyst is in an inactive state, the acceleration request level of the occupant is a predetermined level. only when the occupant has selected the first fuel by large determined to be and the fuel selection means than even catalyst an unactivated state, and the switching so that the first fuel using fuel from a second fuel .

  Specifically, in the first aspect of the invention, the dual fuel engine control that enables switching between the first fuel and the second fuel that has less exhaust emission when the catalyst is inactive than the first fuel is used as the fuel used. Intended for equipment.

The engine torque when the first fuel is used is larger than that when the second fuel is used, and the catalyst state related value detecting means for detecting a value related to the active state of the catalyst, and the catalyst state related Catalyst state determination means for determining whether the catalyst is in an active state or an inactive state based on a value detected by the value detection means; and the first fuel and the second fuel by operation of a vehicle occupant. A fuel selection means capable of selecting one of the fuel, a fuel determination means using one of the first fuel and the second fuel as a fuel to be used, and a value related to the magnitude of the passenger's acceleration request with an acceleration request-related value detecting means, based on the detected value by the acceleration request-related value detecting means, and the acceleration request determining means for determining whether the occupant of the acceleration requirement level is higher than a predetermined level, the The fuel determination means is configured to use the second fuel as a use fuel regardless of the fuel selected by the fuel selection means when the catalyst state determination means determines that the catalyst is in an inactive state. And the fuel determination means further determines the accelerating request of the occupant by the acceleration request determining means when the catalyst state determining means determines that the catalyst is in an inactive state and the second fuel is used. When it is determined that the level is higher than a predetermined level and the first fuel is selected by the fuel selection means, the fuel to be used is switched from the second fuel to the first fuel .

  With the above configuration, when the catalyst is in an inactive state at a cold start such as immediately after the engine is started, the exhaust emission when the catalyst is inactive is less than that of the first fuel. Two fuels will be selected as the fuel used. Accordingly, the exhaust emission can be reduced as compared with the case where the first fuel is used as the used fuel when the catalyst is inactive.

  When the catalyst reaches the activation temperature and is in the active state, for example, by using the fuel selected by the occupant by the fuel selection means as the use fuel, the occupant himself can use the fuel according to the traveling state desired by the occupant. It becomes possible to select. Specifically, for example, when the mileage of the vehicle differs depending on which of the first fuel and the second fuel is used fuel, the mileage is used as the used fuel when the occupant desires driving with a focus on fuel efficiency. For example, the better fuel may be selected.

Further, according to the present invention, for example, as the value related to the magnitude of the acceleration request, the vehicle speed and the accelerator opening are detected, and the required torque of the engine is calculated based on the detected value. By determining whether or not is greater than a predetermined value, it is possible to determine whether or not the acceleration request level indicating the magnitude of the passenger acceleration request is greater than the predetermined level.

Further, even when the acceleration request determination means determines that the acceleration request level of the occupant is greater than a predetermined level and the occupant selects the first fuel by the fuel selection means, even if the catalyst is in an inactive state, The fuel used can be switched from the second fuel to the first fuel.

Therefore, when the catalyst is in an inactive state, although there is a dislike of increasing exhaust emission by using the first fuel as the used fuel, a higher engine torque is obtained compared to the case where the second fuel is used. As a result, for example, in a vehicle (engine-driven vehicle) of a type that transmits the driving force of the engine as a driving source to the driving wheels of the engine via a drive shaft or the like, the driving wheels of the vehicle are driven with high torque. It can be driven to achieve strong acceleration.

Therefore, for example, it is possible to prevent the danger of being collided with a rear vehicle due to insufficient vehicle speed due to insufficient acceleration on an uphill lane on a highway, and as a result, improving the traveling safety of the vehicle. Can do.

Also, for example, in a so-called series hybrid vehicle including a motor for driving the drive wheels and a power generation engine, the same effects as those of the engine-driven vehicle can be obtained.

That is, a series hybrid vehicle normally has a generator (generator) driven by an engine, and drives the motor by electric power supplied from the generator. Therefore, by using the first fuel as the used fuel, it is possible to drive the generator at a higher torque than when the second fuel is used. Therefore, it is possible to supply more electric power from the generator to the motor and drive the drive wheels driven by the motor with high torque.

  According to a second aspect of the present invention, in the control apparatus for a dual fuel engine according to the first aspect, the first fuel is gasoline and the second fuel is hydrogen.

According to this, although hydrogen is used as the second fuel, a little NOx is emitted in the combustion process, but unlike fossil fuels such as gasoline, C (carbon) and S (sulfur) are contained in the fuel. ) Is not included, it is possible to realize a clean engine without discharging CO ₂ (carbon dioxide), SOx, or the like.

According to a third aspect of the present invention, in the control apparatus for a dual fuel engine according to the first or second aspect , the fuel determining means determines that the acceleration request level of the occupant is greater than a predetermined level by the acceleration request determination means and After the first fuel is selected by the fuel selection means and the first fuel is used, the catalyst state is determined when the acceleration request determination means determines that the acceleration request level of the occupant is below a predetermined level. Even if it is determined by the determination means that the catalyst is in an inactive state, the used fuel is maintained as the first fuel without switching from the first fuel to the second fuel. And

  As a result, for example, in a situation where acceleration is frequently repeated, even if the catalyst is in an inactive state, the used fuel can be maintained as the first fuel having a larger engine torque than the second fuel. Therefore, it is possible to suppress a torque shock that occurs when the fuel used is switched from the second fuel to the first fuel when the acceleration is performed again (when the requested acceleration level again exceeds the predetermined level).

As described above, according to the control apparatus for a dual fuel engine of the present invention, one of the first fuel and the second fuel having less exhaust emission when inactive than the first fuel is selected by the occupant's operation. The fuel selection means is provided, and when the catalyst is in an inactive state, the second fuel is used as a fuel regardless of the fuel selected by the fuel selection means , and the catalyst is in an inactive state. Thus, when the second fuel is used as a fuel, the catalyst is not used only when it is determined that the passenger's acceleration request level is higher than the predetermined level and the occupant selects the first fuel by the fuel selection means. even in the active state, by making the fuel used in the switching so that the first fuel from the second fuel, using by the occupant of the intention to realize the running state where the occupant wants While allowing the selection of fuel, Ri FIG reduction of exhaust emissions, and further, it is possible to increase the running safety of the vehicle to secure the required engine torque.

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

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a hybrid vehicle equipped with a control device for a dual fuel engine (hereinafter referred to as an engine) according to an embodiment of the present invention. The vehicle 1 is a so-called series hybrid vehicle that includes an engine 11 and a motor 17 as a power source, the engine 11 is used only for power generation, and the power for moving the vehicle 1 depends entirely on the motor 17. In addition to the engine 11 and the motor 17, the vehicle 1 includes a high voltage battery 12 (hereinafter referred to as a battery 12) and a generator 13 (generator) driven by the engine 11.

  As shown in FIG. 3, the engine 11 can be used by switching between gasoline (corresponding to the first fuel) and hydrogen (corresponding to the second fuel) having different engine torques when used under the same engine operating conditions. The engine torque at the same engine speed and throttle opening is greater when gasoline is used fuel than when hydrogen is used fuel. Further, when the motor 17 is driven by the generator 13 driven by the engine 11 during high torque operation and medium torque operation, which will be described later, compared to the case where hydrogen is used as fuel by using gasoline as fuel. Thus, the rotor (not shown) of the generator 13 can be rotated at high speed with high torque, and as a result, more electric power can be supplied to the motor 17. Accordingly, the output torque of the motor 17 (hereinafter referred to as “motor torque”) is also greater when gasoline is used as fuel than hydrogen when fuel is used at the same engine speed and throttle opening. .

  As shown in FIG. 2, the engine 11 has a generally triangular rotor 24 housed in a rotor housing chamber (hereinafter referred to as a cylinder) 23 surrounded by a bowl-shaped rotor housing having a trochoid inner peripheral surface and a side housing. The three working chambers are defined on the outer peripheral side of the rotor 24. Although not shown, the engine 11 is integrated with two rotor housings sandwiched between three side housings, and the rotors 24 and 24 are accommodated in two cylinders 23 and 23 formed therebetween, respectively. FIG. 2 shows the two rotors 23 and 23 in an expanded state.

  Each of the rotors 24 rotates while rotating around the eccentric shaft 25 in a state where seal portions respectively disposed at three tops of the outer periphery of the rotor 24 are in contact with the inner surface of the trochoid of the rotor housing. Revolves around 25 axes. Then, while the rotor 24 makes one rotation, the working chambers formed between the tops of the rotor 24 move in the circumferential direction, and the intake, compression, expansion (combustion), and exhaust strokes are performed. Is generated from the eccentric shaft 25 via the rotor 24.

  Each cylinder 23 of the engine 11 is provided with two spark plugs 14, 14. The two spark plugs 14, 14 are respectively disposed near the minor axis of the rotor housing, Each cylinder 23 is provided with two hydrogen injection injectors 4 for directly injecting hydrogen supplied from a hydrogen fuel tank 16 (see FIG. 1), which will be described later, into the cylinder (in FIG. Only one is shown), and the two injectors 4 provided in each cylinder 23 are arranged side by side in the axial direction of the eccentric shaft 25 in the vicinity of the long axis of the rotor housing.

  Each cylinder 23 is connected to the intake passage 2 so as to communicate with the working chamber in the intake stroke, and to the exhaust passage 3 so as to communicate with the working chamber in the exhaust stroke. The intake passage 2 is one on the upstream side, but is divided into two on the downstream side and communicates with the working chambers of the cylinders 23. Further, two exhaust passages 3 are provided on the upstream side so as to communicate with the working chambers of the respective cylinders 23, but are joined together on the downstream side. An exhaust purification device (catalytic converter) 30 using a three-way catalyst is disposed downstream of the merging portion of the exhaust passage 3 to purify harmful components such as HC, CO, and NOx in the exhaust gas. The exhaust purification device 30 is provided with a catalyst temperature sensor 35 for detecting the catalyst temperature.

  A throttle valve 22 that is driven by an actuator 21 such as a stepping motor and adjusts the cross-sectional area (valve opening) of the passage 2 is disposed upstream of the branch portion of the intake passage 2. Downstream of the section, gasoline injectors 5 and 5 for injecting gasoline supplied from the gasoline fuel tank 15 (see FIG. 1) into the intake passage 2 (branched portion) are arranged. Yes.

  The ignition plug 14, the actuator 21 of the throttle valve 22, and the injectors 4 and 5 for hydrogen and gasoline injection are controlled by a power train control module 6 (hereinafter referred to as PCM 6). .

  That is, each spark plug 14 is ignited at a predetermined timing according to the rotational position of the rotor 24. The actuator 21 of the throttle valve 22 is controlled by the PCM 6 in accordance with the output signal of the accelerator opening sensor 33 (see FIG. 2) that detects the amount of depression of the accelerator pedal (accelerator opening) of the vehicle occupant. The opening degree of 22 is adjusted. That is, the opening value of the throttle valve 22 corresponds to the output value of the throttle opening sensor 33 (in this embodiment, the actuator 21 also serves as an actuator 21) that detects the opening. And adjust to a predetermined value. Further, the injector 4 for hydrogen injection injects hydrogen into the cylinder 23 (working chamber) at a predetermined timing according to the rotational position of the rotor 24 when the fuel used is hydrogen, and the injector 5 for gasoline injection. Injects gasoline into the intake passage 2 at a predetermined timing according to the rotational position of the rotor 24 when the fuel used is gasoline.

  On the other hand, the battery 12 is connected to a generator 13 and a motor 17 via an AC-DC converter 20a and a DC-AC converter 20b, respectively, as shown in FIG. It is charged when regenerative power from is supplied. The battery 12 is for driving the generator 13 and the motor 17 and supplies electric power to the generator 13 and the motor 17.

  The motor 17 is connected to both drive wheels 18 via a differential gear 19 and has a low output torque (hereinafter referred to as a required torque) required for the motor 17 such as during constant speed operation of the vehicle. Driven by electric power supplied from the battery 12 during low torque operation or vehicle start-up, and driven by electric power supplied from the generator 13 driven by the engine 11 during medium torque operation. During torque operation, it is driven by electric power supplied from both the generator 13 and the battery 12.

  When the amount of power stored in the battery 12 is small, the electric power necessary for driving the motor 17 with the required torque by operating the engine 11 and operating the generator 13 (hereinafter referred to as the necessary electric power of the motor). The generator 13 generates a larger amount of power, and supplies the battery 12 with the difference between the power generated by the generator 13 and the necessary power of the motor 17 to perform charging.

  The AC-DC converter 20a and the DC-AC converter 20b are controlled by the PCM 6, and are configured to control power transfer and conversion among the battery 12, the generator 13, and the motor 17. .

  Specifically, the AC-DC converter 20a converts AC power into DC power, and the DC-AC converter 20b converts DC power into AC power whose frequency is controlled. When supplying power from the generator 13 to the motor 17, the AC power generated by the generator 13 is once converted into DC power by the AC-DC converter 20a, and then again the DC-AC converter 20b. Thus, the DC power is converted to AC power and supplied to the motor 17. Further, when supplying power from the battery 12 to the motor 17, the DC power output from the battery 12 is converted into AC power of a predetermined frequency by the DC-AC converter 20 b and supplied to the motor 17. Is done. Furthermore, when charging the battery 12, the AC power generated by the generator 13 is converted into DC power by the AC-DC converter 20 a and supplied to the battery 12.

  On the other hand, as shown in FIG. 2, a battery current / voltage sensor 31, a vehicle speed sensor 32, an accelerator opening sensor 33, a fuel changeover switch 34, and a catalyst temperature sensor 35 can exchange signals with the PCM 6. It is connected to the.

  The battery current / voltage sensor 31 detects the current intensity and voltage of the battery 12. When the battery current / voltage sensor 31 detects the current intensity and voltage of the battery 12, the battery current / voltage sensor 31 outputs a detection signal to the PCM 6. When the PCM 6 receives the detection signal from the battery current / voltage sensor 31, the PCM 6 calculates the storage amount of the battery 12 and the charge / discharge amount of the battery 12. When the calculated amount of electricity stored in the battery 12 falls below a predetermined amount, the PCM 6 operates the generator 11 by operating the engine 11 so that the amount of electricity stored in the battery 12 becomes equal to or greater than the predetermined amount. Charge the battery.

  The accelerator opening sensor 33 detects the opening of an accelerator (not shown) of the vehicle 1 and outputs a detection signal to the PCM 6 when the accelerator opening is detected.

  The vehicle speed sensor 32 detects the vehicle speed of the vehicle 1 and outputs a detection signal to the PCM 6 when the vehicle speed is detected.

  When the PCM 6 receives the detection signals from the accelerator opening sensor 33 and the vehicle speed sensor 32, the PCM 6 calculates (estimates) the required torque and, based on the required torque, the presence or absence of an operation request for the engine 11, that is, the engine 11 It is determined whether or not it is necessary to drive the vehicle and the magnitude of the acceleration request (acceleration request level) of the passenger.

  Specifically, from the map shown in FIG. 4, when the required torque is larger than the first predetermined value, the PCM 6 has an operation request for the engine 11 as requiring the above-described medium torque operation and high torque operation. On the other hand, when the required torque is equal to or less than the first predetermined value, it is determined that there is no operation request for the engine 11 because the low torque operation described above is required. Here, the boundary line between the request for engine operation and the request for no engine operation in FIG. 4 is an equal torque line corresponding to the first predetermined value.

  Furthermore, the PCM 6 determines from the map shown in FIG. 4 that the requested acceleration level is greater than the predetermined level when the requested torque is greater than the second predetermined value when there is an engine operation request, and the requested torque is When it is equal to or smaller than two predetermined values, it is determined that the acceleration request level is lower than the predetermined level. Here, the boundary line between the high acceleration request level and the low acceleration request level in FIG. 4 is an equal torque line corresponding to the second predetermined value (predetermined level). Accordingly, the accelerator opening sensor 33 and the vehicle speed sensor 32 constitute acceleration request related value detection means for detecting a value related to the passenger's acceleration request, and the PCM 6 is a value detected by the acceleration request related value detection means. The determination means for determining whether the acceleration request level of the occupant is higher than a predetermined level based on the above is configured.

  On the other hand, the catalyst temperature sensor 35 detects the catalyst temperature as described above, and outputs the detection signal to the PCM 6. The PCM 6 receives a detection signal from the catalyst temperature sensor 35 and determines whether the catalyst is in an active state, that is, whether the catalyst is in an active state or in an inactive state, and is preferable for reducing exhaust emission ( (Hereinafter referred to as exhaust optimization fuel) is selected based on the active state of the catalyst. Specifically, when the detected catalyst temperature is equal to or higher than the activation temperature (350 ° C. in this embodiment), the PCM 6 determines that the catalyst is in an active state and selects gasoline as the exhaust optimization fuel. On the other hand, when the catalyst temperature is lower than the activation temperature, it is determined that the catalyst is in an inactive state, and hydrogen with less exhaust emission in the inactive state than gasoline is selected as the exhaust optimization fuel.

  Thus, the catalyst temperature sensor 35 constitutes a catalyst state related value detecting means for detecting a value related to the active state of the catalyst (catalyst temperature in the present embodiment), and the PCM 6 is used for the catalyst state related value. Based on the value detected by the detection means, a catalyst state determination means for determining whether the catalyst is in an active state or an inactive state is configured.

  The fuel changeover switch 34 is for selecting a fuel required by the occupant as the fuel to be used (hereinafter referred to as a occupant's required fuel) from gasoline and hydrogen, and is provided on an instrument panel (not shown). An occupant can display instructions on a touch panel display 74 (see FIG. 7) of the navigation device. As shown in FIG. 7, the fuel changeover switch 34 includes a hydrogen selection button 34a for selecting hydrogen and a gasoline selection button 34b for selecting gasoline, and the two buttons 34a, 34b. When one of the buttons is selected by touching the finger with a finger, the selection signal corresponding to the selected button 34a, 34b is continuously output to the PCM 6. Specifically, for example, when the hydrogen selection button 34a is selected, the fuel changeover switch 34 continuously outputs a selection signal corresponding to the button 34a, and then when the gasoline selection button 34b is selected, The selection signal corresponding to the button 34b is continuously output. The PCM 6 receives the selection signal from the fuel changeover switch 34 and identifies the fuel required by the passenger. Therefore, the fuel changeover switch 34 constitutes a fuel selection means that can select one of the first fuel and the second fuel by the operation of the occupant of the vehicle 1.

  Then, the PCM 6 compares the exhaust optimization fuel selected by the PCM 6 based on the detection signal from the catalyst temperature sensor 35 with the occupant demand fuel selected by the fuel switch 34. The fuel to be used is determined, and the fuel injection injectors 4 and 5 corresponding to the fuel to be used are driven to operate the engine 11. Thus, the PCM 6 constitutes a fuel determination means that uses one of the first fuel and the second fuel as the fuel used.

  Specifically, when the PCM 6 determines that the catalyst is in an active state based on a detection signal from the catalyst temperature sensor 35 in the PCM 6 and gasoline is selected as the exhaust optimization fuel, The demand fuel selected by the occupant by the fuel changeover switch 34 is configured to be used as fuel in preference to gasoline selected as the exhaust optimization fuel.

  On the other hand, when it is determined by the PCM 6 that the catalyst is in an inactive state and hydrogen is selected as the exhaust optimization fuel, gasoline (gasoline selection button 34b) is selected by the fuel changeover switch 34. Is selected as the above-mentioned exhaust optimization fuel by prohibiting the selected gasoline from being used as a fuel for use except when a predetermined condition 1 or a predetermined condition 2 described later is satisfied. Hydrogen used as fuel.

  In other words, when it is determined by the PCM 6 that the catalyst is in an inactive state, the PCM 6 uses the fuel changeover switch 34 except when a predetermined condition 1 or a predetermined condition 2 described later is satisfied. Regardless of the fuel selected, hydrogen is the fuel used.

  Here, a warning panel 73 is displayed on the display 74 to notify that when it is prohibited to use gasoline as a fuel. In the present embodiment, the display 74 always displays two buttons, the gasoline selection button 34b and the hydrogen selection button 34a. However, the present invention is not limited to this. For example, PCM6 By controlling the display on the display 74 by the above, when it is prohibited to use gasoline as the fuel as described above, the gasoline selection button 34b is not displayed, and the fuel changeover switch 34 does not display the gasoline. The selection itself may be made impossible.

  The PCM 6 has a predetermined acceleration request level when the predetermined condition 1 is satisfied, that is, when the PCM 6 determines that the catalyst is in an inactive state and hydrogen is selected as the fuel to be used. When it is determined that the fuel level is greater than the level and gasoline is selected by the fuel changeover switch 34, the fuel is switched from hydrogen to gasoline without prohibiting the use of the gasoline.

  That is, it can be said that the PCM 6 is configured to use the fuel selected by the fuel changeover switch 34 as the used fuel when the predetermined condition 1 is satisfied.

  Furthermore, the PCM 6 determines that when the predetermined condition 2 is satisfied, that is, when the PCM 6 determines that the occupant acceleration request level is higher than the predetermined level and the fuel changeover switch 34 selects gasoline, If it is determined that the passenger's acceleration request level has become equal to or lower than the predetermined level after the gasoline is used, even if the PCM 6 determines that the catalyst is in an inactive state, the exhaust optimization fuel It is configured to keep the gasoline as it is without switching to the hydrogen selected.

  Next, a specific processing operation for determining the fuel to be used in the PCM 6 will be described with reference to FIGS.

  First, in the first step S1, detection signals output from the vehicle speed sensor 32, accelerator opening sensor 33, and battery current / voltage sensor 31, and a selection signal output from the fuel changeover switch 34 are read.

  In step S2, based on the detection signal read in step 1, it is determined whether or not there is an operation request for the engine 11. If the determination in step S2 is YES, the process proceeds to step S3, and if NO, the process proceeds to step S9.

  In step S3, the catalyst temperature is read based on the detection signal from the catalyst temperature sensor 35. In step S4, it is determined from the read catalyst temperature whether the catalyst is in an active state or an inactive state. If the determination in step S4 is YES, the process proceeds to step S5, and if NO, the process proceeds to step S6.

  In step S5, the fuel selected by the fuel changeover switch 34 is set as the used fuel, and the process returns.

  On the other hand, in step S6, which proceeds to NO in step S4, it is determined whether or not the acceleration request level is higher than a predetermined level and gasoline is selected by the fuel changeover switch 34. If the determination in step S6 is YES, the process proceeds to step S8, and if NO, the process proceeds to step S7.

  In step S7, hydrogen is selected as the fuel to be used and the process returns. In step S8, gasoline is selected as the fuel to be used and the process proceeds to step S11 (see FIG. 6).

  On the other hand, in step S9, which proceeds when the answer is NO in step S2, it is determined whether or not the engine is in an operating state. If the determination in step S9 is YES, the process proceeds to step S10 and the engine is stopped and returned. To do. If the determination in step S9 is NO, the process returns with the engine stopped.

  In step S11 (see FIG. 6), the detection signal output from each of the vehicle speed sensor 32, the accelerator opening sensor 33, and the battery current / voltage sensor 31 and the selection signal output from the fuel switch 34 are again displayed. Read.

  In step S12, based on the detection signal read in step 11, it is determined whether there is an operation request for the engine 11. If the determination in step S12 is yes, the process proceeds to step S13. If the determination is no, the process proceeds to step S17 and the engine is stopped and the process returns.

  In step S13, it is determined whether the acceleration request level is equal to or lower than a predetermined level. If the determination in step 13 is YES, the process proceeds to step 14, and if NO, the process proceeds to step S16.

  In step S14, it is determined whether or not hydrogen is selected by the fuel changeover switch 34. If the determination in step S14 is yes, the process proceeds to step S15, where hydrogen is used as the fuel, and the process returns.

  On the other hand, in step S16 which proceeds when NO in step S13 and step S14, gasoline is continuously used as the fuel to be used, and the process returns to step 11.

As described above, in the above embodiment, when the PCM 6 determines that the catalyst is active based on the detection signal from the catalyst temperature sensor 35, the PCM 6 selects the occupant by the fuel changeover switch 34. The required fuel is used as fuel. Thereby, after a catalyst will be in an active state, the fuel to be used can be selected by a passenger | crew's will. Therefore, it becomes possible for the occupant to select an appropriate fuel to be used in accordance with the traveling situation desired by the occupant. Specifically, for example, when the occupant desires a traveling state that places importance on the environment, the fuel changeover switch 34 selects hydrogen as the fuel to be used, but some NOx is generated, but SOx or CO ₂ (carbon dioxide). It is possible to run cleanly without any emissions. Further, for example, when traveling with an emphasis on torque is desired, gasoline having a larger engine torque than hydrogen may be selected as the fuel to be used by the fuel switch 34. In this case, since the catalyst is in an active state, NOx and HC harmful substances generated during gasoline combustion can be oxidized or reduced by the catalyst to reduce exhaust emissions.

  In the above embodiment, when it is determined by the PCM 6 that the catalyst is in an inactive state, the PCM 6 satisfies the predetermined condition 1 or the predetermined condition 2 (the catalyst is in an inactive state). Except when the acceleration request level exceeds a predetermined level and gasoline is selected by the fuel changeover switch 34), hydrogen is used regardless of the fuel selected by the fuel changeover switch 34. It is configured as follows.

  As a result, the gasoline is not used as the fuel in the catalyst inactive state except when there is a large acceleration request from the passenger. That is, it is possible to prevent gasoline from being selected as the fuel to be used in a state where the catalyst purification function is not functioning, and as a result, it is possible to reliably reduce exhaust emissions.

  Further, in the above embodiment, the PCM 6 determines that the passenger's acceleration request level is higher than the predetermined level when the PCM 6 determines that the catalyst is in an inactive state and hydrogen is selected as the fuel to be used. When gasoline is selected by the fuel switch 34, the fuel is switched from hydrogen to gasoline without prohibiting the use of the gasoline. Thus, when the occupant wants to accelerate the vehicle, the fuel changeover switch 34 selects gasoline having a larger engine torque than hydrogen and uses it as fuel to obtain a high motor torque. Can be accelerated. Therefore, for example, when the occupant depresses the accelerator and the acceleration speed exceeds the predetermined level when the occupant depresses the accelerator on the uphill lane of the highway, and the occupant selects gasoline by the fuel changeover switch 34, the vehicle is used as gasoline as fuel. It can be surely accelerated. Therefore, it is possible to prevent a rear-end collision from the rear vehicle due to insufficient vehicle speed due to insufficient acceleration of the vehicle speed, and it is possible to improve the traveling safety of the vehicle.

  Furthermore, in the above embodiment, after the PCM 6 determines that the passenger's acceleration request level is higher than the predetermined level in the PCM 6 and the gasoline is selected by the fuel changeover switch 34 and the fuel to be used is the gasoline, When it is determined that the accelerating request level of the occupant is below a predetermined level, even if it is determined by the PCM 6 that the catalyst is in an inactive state, the fuel used is not changed to hydrogen but is maintained as the gasoline. It is configured as follows. That is, as can be seen from the flowchart of FIG. 6, after the PCM 6 determines that the passenger's acceleration request level is higher than a predetermined level and the gasoline is selected by the fuel changeover switch 34 and the fuel used is the gasoline. That is, in step S8 and subsequent steps, unless the occupant selects hydrogen by the fuel changeover switch 34, the occupant does not intend to switch the fuel used from gasoline to hydrogen.

  Therefore, for example, when there is a situation in which overtaking is frequently performed with respect to the preceding vehicle on an expressway or the like, a torque shock is generated when the fuel used is switched from hydrogen to gasoline each time the overtaking is performed, so that the ride comfort of the vehicle is increased. Can be prevented from being damaged.

(Other embodiments)
The configuration of the present invention is not limited to the above embodiment, but includes various other configurations. That is, in the above embodiment, a series hybrid vehicle is adopted as a vehicle on which the dual fuel engine 11 is mounted. However, the present invention is not limited to this, and for example, the vehicle is used with the engine 11 and the motor 17 as a power source. It is good also as a parallel hybrid vehicle which is equipped and moves by both these motive powers, or may be an engine drive vehicle which has only an engine as a power source.

  Further, in the above embodiment, it is possible to switch between gasoline and hydrogen as the fuel to be used, but it is not limited to this. For example, natural gas may be used instead of hydrogen, or instead of gasoline. Light oil may be employed.

  Further, in each of the above embodiments, the fuel changeover switch 34 is configured by the touch panel type display 74 of the navigation device. However, for example, each of the buttons 34a and 34b is a mechanical switch (for example, a push type). You may comprise.

  In each of the above embodiments, when the fuel is selected by the fuel changeover switch 34, a selection signal corresponding to the selected button 34a, 34b among the hydrogen selection button 34a and the gasoline selection button 34b is output to the PCM 6. However, the present invention is not limited to this. For example, the selection signal may be output to the PCM 6 only when the buttons 34a and 34b are selected. In this case, for example, the selection signal may be stored in the RAM or the like in the PCM 6 and, when a new selection signal is received, the selection signal may be newly stored in the RAM. In this case, when the selection signal corresponding to the hydrogen selection button 34a is stored in the RAM of the PCM 6, the hydrogen selection is made by the fuel changeover switch 34, and the selection corresponding to the gasoline selection button 34b is selected. The time when the signal is stored may be the time when gasoline is selected by the fuel changeover switch 34.

  INDUSTRIAL APPLICABILITY The present invention is useful for a control device for a dual fuel engine that can be driven by selectively switching between two fuels used, and is particularly useful for a control device for a dual fuel engine that includes a catalytic converter for purifying exhaust gas.

It is a figure showing the whole hybrid vehicle composition provided with the control device of the dual fuel engine concerning the embodiment of the present invention. It is a schematic block diagram which shows the control apparatus of a dual fuel engine. It is a figure which shows the relationship between a throttle opening and the maximum output torque of an engine. It is a figure which shows an example of a fuel switching map. It is a flowchart which shows the processing operation regarding the fuel switching by the control apparatus of a dual fuel engine. It is a flowchart which shows the processing operation regarding the fuel switching by the control apparatus of a dual fuel engine. It is a figure which shows the fuel changeover switch displayed on the display of a navigation apparatus.

6 Powertrain control module (Fuel determination means) (Catalyst state determination means)
(Acceleration request determination means)
11 Dual fuel engine 32 Vehicle speed sensor (Acceleration request related value detection means)
33 Accelerator opening sensor (acceleration request related value detection means)
34 Fuel changeover switch (second fuel selection means)
35 Catalyst temperature sensor (catalyst state related value detection means)

Claims (3)

A dual fuel engine control device mounted on a vehicle and capable of switching between a first fuel and a second fuel that has less exhaust emission when the catalyst is inactive than the first fuel,
The engine torque when using the first fuel is larger than when using the second fuel,
Catalyst state related value detecting means for detecting a value related to the active state of the catalyst;
Catalyst state determination means for determining whether the catalyst is in an active state or an inactive state based on a value detected by the catalyst state related value detection means;
Fuel selection means capable of selecting one of the first fuel and the second fuel by an operation of an occupant of the vehicle;
Fuel determining means using one of the first fuel and the second fuel as a fuel used ;
Acceleration request related value detection means for detecting a value related to the magnitude of the acceleration request of the passenger,
Acceleration request determination means for determining whether or not the acceleration request level of the occupant is higher than a predetermined level based on the value detected by the acceleration request related value detection means ,
The fuel determination means is configured to use the second fuel as a use fuel regardless of the fuel selected by the fuel selection means when the catalyst state determination means determines that the catalyst is in an inactive state. It is,
The fuel determining means further determines the acceleration request level of the occupant by the acceleration request determining means when the catalyst state determining means determines that the catalyst is in an inactive state and the second fuel is used. The dual fuel tank is configured to switch the used fuel from the second fuel to the first fuel when it is determined that the level is greater than a predetermined level and the first fuel is selected by the fuel selection means. Fuel engine control device. The control apparatus for a dual fuel engine according to claim 1,
The first fuel is gasoline,
The control apparatus for a dual fuel engine, wherein the second fuel is hydrogen. The dual fuel engine control device according to claim 1 or 2 ,
The fuel determination means determines that the acceleration request level of the occupant is greater than a predetermined level by the acceleration request determination means, and the first fuel is selected by the fuel selection means and the first fuel is used as fuel. Thereafter, when it is determined by the acceleration request determination means that the acceleration request level of the occupant has become a predetermined level or less, the fuel selection means even if the catalyst state determination means determines that the catalyst is in an inactive state. The dual fuel engine is configured to maintain the first fuel as it is without switching from the first fuel to the second fuel unless the second fuel is selected by Control device.

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