JP4508178B2 - Control device for hybrid vehicle equipped with dual fuel engine - Google Patents

Description

  The present invention belongs to a technical field related to a hybrid vehicle including a dual fuel engine and a motor that can be used by selectively switching two fuels.

  Conventionally, as a hybrid vehicle equipped with an engine and a motor, the engine is exclusively used for power generation and travels using only the motor as a drive source, and both the engine and the motor are used as drive sources as required. A parallel system that travels by changing the distribution of each driving force is known.

  In general, the hybrid vehicle operates the engine during high load operation with high engine efficiency, and when the series system is employed, the hybrid vehicle is driven by electric power from a generator driven by the engine. When the parallel system is adopted, the engine and the motor driven by the electric power from the battery are used together, while the engine efficiency is low and the load is low. In some cases, the engine is stopped and the vehicle is driven using only the motor as a drive source when any of the above methods is employed. As a result, the engine is stopped during low load operation with low engine efficiency to improve fuel efficiency.

  Therefore, in a normal hybrid vehicle, for example, in a situation where low-load operation continues, the engine cannot be heated with exhaust heat as a result of the engine being stopped for a long time. For this reason, the catalyst temperature is lower than the activation temperature. There is a problem that exhaust emission increases, and various catalyst temperature maintaining techniques have been proposed to solve this problem.

For example, in the hybrid vehicle shown in Patent Document 1, a temperature sensor for detecting the temperature of the catalyst and a catalyst heater for heating the catalyst are provided, and the temperature detected by the temperature sensor tends to decrease. In some cases, even if there is no request for engine operation, the engine is forcibly operated to heat the catalyst by the exhaust heat and keep the temperature above the activation temperature. Thereby, after the engine is restarted, the exhaust emission generated due to the lack of the purification ability of the catalyst until the catalyst reaches the activation temperature is suppressed.
Japanese Patent Laid-Open No. 11-210448

  By the way, in recent years, in order to reduce exhaust emission during engine operation, a dual fuel engine capable of switching between, for example, hydrogen and gasoline has been developed as a fuel to be used, and the dual fuel engine is employed as an engine of a hybrid vehicle. Thus, it is conceivable to achieve both improvement in fuel consumption and reduction in exhaust emission by hybridizing the engine and motor.

  However, as described above, in a hybrid vehicle employing a dual fuel engine that can be used by switching between two fuels, for example, when the fuel to be used at the time of engine restart is hydrogen fuel with low exhaust emission in a catalyst inactive state Until now, if the engine operation for maintaining the catalyst temperature at the activation temperature or higher is performed as in the above-mentioned Patent Document 1, there is a problem in that fuel consumption is unnecessarily consumed, resulting in deterioration of fuel consumption.

  Furthermore, when the above dual fuel engine is adopted, there is a demand for selecting the fuel to be used based on the occupant's intention. To meet this demand, for example, one of the first fuel and the second fuel is operated by the occupant. It is conceivable to further provide a fuel selection means capable of selecting the fuel as the used fuel.

  However, in this case, the first fuel may be selected by the fuel selection means even though the catalyst temperature is lower than the activation temperature. As a result, the catalyst purification function functions sufficiently. Without it, there is a problem that exhaust emission increases.

  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. For a hybrid vehicle comprising a dual fuel engine that can be switched between and a motor capable of outputting the driving force of the vehicle and configured to be able to travel only with the driving force of the motor while the engine is stopped, By elaborating the configuration and control, it is intended to achieve both reduction of exhaust emission and improvement of fuel consumption while enabling selection of fuel to be used based on the occupant's intention.

  In order to achieve the above object, the present invention includes fuel selection means that can select one of the first fuel and the second fuel by the operation of a vehicle occupant, and the catalyst temperature is higher than the activation temperature. When the temperature is equal to or higher than a predetermined temperature and the engine is stopped, when the first fuel is selected by the fuel selection means and the catalyst temperature decreases and reaches the predetermined temperature, the engine is On the other hand, when the second fuel is selected by the fuel selection means, the engine is kept stopped even when the catalyst temperature decreases and reaches the predetermined temperature. I did it.

  Specifically, in the invention of claim 1, a dual fuel engine that can switch between the first fuel and the second fuel that has less exhaust emission when the catalyst is inactive than the first fuel as the fuel used; A control device for a hybrid vehicle that includes a motor capable of outputting a driving force of the vehicle and is configured to be able to travel only with the driving force of the motor while the engine is stopped.

And a catalyst temperature detecting means for detecting the temperature of the catalyst, a fuel selecting means capable of selecting one of the first fuel and the second fuel by an operation of an occupant of the vehicle, and the catalyst temperature. In response to information on the catalyst temperature detected by the detecting means and the fuel selected by the fuel selecting means, one of the first fuel and the second fuel is selected, and the selected fuel is used as the fuel to be used. Engine operation control means for controlling the operation of the engine as
The engine operation control means includes the fuel selection means when the catalyst temperature detected by the catalyst temperature detection means is equal to or higher than a predetermined temperature set to be equal to or higher than the activation temperature of the catalyst and the engine is stopped. When the first fuel is selected by the above and the catalyst temperature detected by the catalyst temperature detecting means decreases and reaches the predetermined temperature, the engine is operated to keep the catalyst temperature above the activation temperature. On the other hand, when the second fuel is selected by the fuel selection means, the activation temperature holding control is prohibited even when the catalyst temperature reaches the predetermined temperature. It is assumed that

  With the above configuration, it is possible to achieve both reduction of exhaust emission and improvement of fuel consumption while enabling selection of fuel to be used based on the occupant's intention.

  That is, in a hybrid vehicle, the engine may be stopped for a long time due to low load operation, or the engine stop and operation may be frequently repeated depending on the traveling state. For this reason, when the engine is in a stopped state, the catalyst cannot be heated by the exhaust heat of the engine, and as a result, the catalyst temperature decreases with time. For example, if the catalyst temperature immediately after the engine is stopped (the catalyst temperature detected by the catalyst temperature detecting means) is higher than the predetermined temperature, the catalyst temperature decreases with time and eventually reaches the predetermined temperature. According to the present invention, when the fuel selected by the fuel selection means is the first fuel at this time, the activation temperature holding control is executed by the engine control means. Even if there is no request for operation, the catalyst is forcibly operated so as to keep the catalyst temperature above the activation temperature. In the following explanation, when the engine is in a stopped state, the operation that is started even though there is no operation request for the engine is referred to as the forced operation of the engine, and this is responded to when there is an engine operation request. The operation started in this manner is called engine restart.

  When the engine is forcibly operated, for example, after the catalyst temperature decreases and reaches the predetermined temperature, the engine is forced until the catalyst temperature reaches a second predetermined temperature set higher than the predetermined temperature. It can be considered that the forced operation is stopped when the catalyst temperature reaches the second predetermined temperature. In this case, the catalyst temperature that has been lowered to the predetermined temperature because the engine is in a stopped state before the forced operation is increased from the predetermined temperature to the second predetermined temperature by the forced operation of the engine, and then the engine When the engine is stopped, the temperature is lowered to the predetermined temperature, and then the engine is forcibly operated to rise again to the second predetermined temperature. In this way, once the catalyst temperature reaches the predetermined temperature, the forced operation and the stop of the engine are alternately repeated to increase and decrease between the predetermined temperature and the second predetermined temperature. By repeating alternately, the temperature is always kept above a predetermined temperature.

  On the other hand, as described above, after the engine is stopped, when the catalyst temperature immediately after the stop is higher than the predetermined temperature, the catalyst temperature decreases and eventually reaches the predetermined temperature. When the second fuel is selected by the fuel selection means at the time of arrival, the activation temperature holding control by the engine control means is prohibited, unlike when the first fuel is selected. Therefore, the engine is maintained in a stopped state. Therefore, the catalyst temperature continues to decrease further and eventually falls below the activation temperature.

  By the way, in order to make it possible to select the fuel to be used based on the occupant's intention, for example, if the first fuel is selected when the catalyst temperature decreases and reaches the predetermined temperature, there is an engine operation request thereafter. When the engine is restarted, the first fuel is used as the fuel for use. On the other hand, if the second fuel is selected, the second fuel can be used as the fuel for use.

  In this case, when the first fuel is selected by the fuel selection means when the catalyst temperature decreases and reaches the predetermined temperature, the first fuel is used as the fuel to be used according to the subsequent engine operation request. The engine restarts. The re-operation is started when the catalyst temperature is maintained at a predetermined temperature or higher (above the activation temperature) by repeating the forced operation and stop of the engine as described above. Therefore, the catalyst temperature can always be kept at the activation temperature or higher during the re-operation, and therefore, the generation of exhaust emission due to the lack of the catalyst purification ability due to the catalyst temperature being lower than the activation temperature is suppressed. can do.

  Also, instead of continuously forcing the engine to keep the catalyst temperature above the activation temperature, as described above, for example, by repeatedly stopping and forcing the engine, It becomes possible to shorten the driving time and improve the fuel consumption of the vehicle.

  Furthermore, by setting the predetermined temperature higher than the activation temperature, for example, the engine can be forcibly started before the catalyst temperature reaches the activation temperature. Even if it is slightly delayed, the engine can be forcibly operated before the catalyst temperature falls below the activation temperature, and the generation of the exhaust emission can be suppressed.

  On the other hand, when the second fuel is selected by the fuel selection means when the catalyst temperature decreases and reaches the predetermined temperature, the engine is restarted using the second fuel as a used fuel according to a subsequent engine operation request. Operation starts. This re-operation is started when the catalyst temperature is lower than the activation temperature because the activation temperature holding control is prohibited as described above, but the exhaust emission when the catalyst is inactive as the fuel to be used is started. Since a small amount of the second fuel is used, the exhaust emission is not significantly increased by the re-operation. Therefore, as described above, when the second fuel is selected by the fuel selection means, the activation temperature holding control by the engine operation control means is prohibited, thereby suppressing the generation of exhaust emission. Thus, it becomes possible to eliminate the forced operation of the engine to keep the catalyst temperature at the activation temperature or higher, thereby improving the fuel consumption. In the following description, when the activation temperature holding control is not performed, the time when the catalyst temperature is lower than the activation temperature is referred to as the time when the catalyst temperature is lowered.

  According to a second aspect of the present invention, in the hybrid vehicle control apparatus 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, CO ₂ (carbon dioxide), SO _{X, and the} like are not discharged. Therefore, exhaust emission can be reduced as compared with a hybrid vehicle equipped with a normal gasoline engine.

In the invention of claim 3, in the hybrid vehicle control device of claim 1 or 2,
Fuel selection prohibiting means for prohibiting selection of the first fuel by the fuel selection means when the catalyst temperature is lower than the activation temperature due to prohibition of execution of the activation temperature holding control is provided. .

  As a result, it is possible to reduce the exhaust emission while making it possible to select the fuel to be used based on the passenger's intention.

  That is, in order to make it possible to select the fuel used based on the occupant's intention, for example, the fuel selected by the fuel selection means when the engine operation is requested is used as the fuel used when the engine is restarted. Can be considered. In this case, if the first fuel is newly selected by the fuel selection means when the catalyst temperature is lowered, the engine restart is started using the first fuel as the used fuel according to the subsequent engine operation request. Is done. As a result, although the catalyst temperature is in an inactive state, there is a problem that the engine restart is started using the first fuel as the used fuel, and the exhaust emission is remarkably increased.

  However, according to the present invention, when the catalyst temperature is lowered, the selection of the first fuel is prohibited by the fuel selection means, so that the second fuel is always selected. As a result, when there is an engine operation request The engine is restarted using the second fuel as a used fuel. As a result, when the catalyst is in an inactive state, the engine can be restarted using the second fuel with less exhaust emission as the used fuel, and the generation of exhaust emission can be reliably suppressed.

  According to a fourth aspect of the present invention, in the hybrid vehicle control device according to the first or second aspect, the engine operation control means prohibits the execution of the activation temperature maintaining control so that the catalyst temperature falls below the activation temperature. When the first fuel is selected by the fuel selection means, the engine is operated using the second fuel as the fuel to be used, and the catalyst temperature is raised to the activation temperature or higher. It shall be.

  As a result, it is possible to reduce the exhaust emission while making it possible to select the fuel to be used based on the passenger's intention.

  That is, in order to enable the fuel selection based on the intention of the occupant, for example, when the first fuel is newly selected by the fuel selection means when the catalyst temperature is lowered, the first fuel It is conceivable to start the engine again with the fuel used. In this case, although the catalyst is in an inactive state, the engine is restarted using the first fuel as a used fuel, and as a result, there is a problem that exhaust emission is remarkably increased.

  However, according to the present invention, when the first fuel is selected by the fuel selection means when the catalyst temperature is lowered, the engine is forced to use the second fuel as the used fuel so that the catalyst temperature becomes equal to or higher than the activation temperature. Operation starts. Therefore, for example, when the engine restart is requested after the catalyst temperature becomes higher than the activation temperature and the engine restart is started, the catalyst temperature can always be kept higher than the activation temperature during the restart. As a result, the generation of exhaust emission can be reliably suppressed as compared with the case where the forced operation is not performed. Further, the forced operation that is started when the catalyst temperature is lowered uses the second fuel as the fuel to be used, and therefore the exhaust emission does not increase significantly.

  If there is an engine operation request before the catalyst temperature rises to the activation temperature due to the forced operation, for example, the second fuel with less exhaust emission is used until the catalyst temperature reaches the activation temperature. The engine may be restarted as fuel. As a result, it is possible to reliably prevent the generation of exhaust emission due to the engine being restarted using the first fuel as the used fuel even though the catalyst temperature is in an inactive state.

  According to a fifth aspect of the present invention, in the hybrid vehicle control device according to the first or second aspect, the driving request determining means for determining the presence or absence of the engine driving request is provided, and the engine driving control means is configured to maintain the activation temperature. When the first fuel is selected by the fuel selection means when the catalyst temperature is lower than the activation temperature due to prohibition of control, the operation request determination means determines that there is an engine operation request. Until the catalyst temperature reaches the activation temperature, the engine is used as a used fuel until the engine is stopped. On the other hand, after the activation temperature is reached, the engine is operated using the first fuel as a used fuel. It is assumed to be configured.

  As a result, when the first fuel is selected by the fuel selection means at the time of the catalyst temperature drop, the engine restart is started using the second fuel as the used fuel after waiting for an engine operation request. . After that, after the catalyst temperature reaches the activation temperature, the re-operation is performed using the first fuel as the used fuel. Therefore, whenever the catalyst is in an inactive state, the re-operation is performed using the second fuel as the used fuel, so that exhaust emission can be reliably reduced. In addition, after the catalyst temperature reaches the activation temperature, the above re-operation can be performed using the first fuel selected by the fuel selection means as the occupant's required fuel, so that the exhaust emission can be reduced. However, it is possible to select the fuel used based on the passenger's intention.

  As described above, according to the hybrid vehicle of the present invention, the vehicle is equipped with fuel selection means capable of selecting one of the first fuel and the second fuel by being operated by the vehicle occupant, and the catalyst temperature is higher than the activation temperature. When the temperature is equal to or higher than a predetermined temperature and the engine is stopped, when the first fuel is selected by the fuel selection means and the catalyst temperature decreases and reaches the predetermined temperature, the engine is Even if there is no operation request, the engine is forcibly operated. On the other hand, when the second fuel is selected by the fuel selection means, the engine is forcibly operated even when the catalyst temperature decreases and reaches the predetermined temperature. Without stopping the engine, it is possible to select the fuel to be used based on the will of the occupant, while improving fuel economy and reducing exhaust emissions. It is possible to achieve both.

  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 1 equipped with 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 power sources, 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.

  The engine 11 is configured to be able to switch between gasoline (corresponding to the first fuel) and hydrogen (corresponding to the second fuel) with less exhaust emission (described later) when the catalyst is inactive than gasoline as the fuel used. Has been.

  As shown in FIG. 3, the engine torque at the same engine speed and throttle opening is greater when gasoline is used as fuel than when hydrogen is used. 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. .

  The engine 11 includes 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, and a substantially triangular rotor 24 accommodated therein. 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. In the following description, the harmful component contained in the exhaust gas after passing through the catalyst (catalytic converter 30) is referred to as exhaust emission.

  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 according to 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 occupant of the vehicle 1. The opening degree of the valve 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 an output torque (hereinafter referred to as a required torque) required for the motor 17 such as during constant speed operation of the vehicle 1 is obtained. 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, the required torque during sudden acceleration is high. At the time of high 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 required 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 is configured to convert 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 a predetermined value. 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.

  Specifically, the PCM 6 determines from the map shown in FIG. 4 that when the required torque is greater than a predetermined value, there is an operation request for the engine 11 as the above-described middle torque operation and high torque operation are required. On the other hand, when the required torque is equal to or less than the predetermined value, it is determined that there is no request for operation of 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 predetermined value. The PCM 6 constitutes an operation request determination unit that determines the presence or absence of an operation request for the engine 11.

  On the other hand, the catalyst temperature sensor 35 is composed of, for example, a thermocouple, a thermistor, etc., and detects the temperature of exhaust gas passing through the catalytic converter 30 and outputs a detection signal (voltage signal) to the PCM 6. The PCM 6 receives the detection signal from the catalyst temperature sensor 35 and estimates (calculates) the catalyst temperature. Therefore, the catalyst temperature sensor 35 constitutes a catalyst temperature detecting means for detecting the temperature of the catalyst.

  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 is displayed on the touch panel display 74 (see FIG. 5A) of the navigation device so as to be instructed. As shown in FIG. 5A, the fuel changeover switch 34 includes a hydrogen selection button 34a for selecting hydrogen and a gasoline selection button 34b for selecting gasoline. When the passenger touches and selects one of 34a and 34b with his / her finger, the selection signal corresponding to the selected button 34a or 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. Specifically, when the selection signal corresponding to the hydrogen selection button 34a is received, the passenger's requested fuel is identified as hydrogen, and when the selection signal corresponding to the gasoline selection button 34b is received, the required fuel is gasoline. Is identified. 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 passenger.

  The PCM 6 determines the fuel to be used on the basis of the detection signal from the catalyst temperature sensor 35 and the occupant's requested fuel selected by the fuel changeover switch 34, and for fuel injection corresponding to the fuel to be used. The engine 11 is operated by driving the injectors 4 and 5.

  Specifically, the PCM 6 determines the presence / absence of an operation request based on the selection signals from the various sensors and the fuel changeover switch 34, determines the fuel to be used, and supplies the fuel to the injectors 4, 5 and the throttle valve 22 and the like. A main control unit (not shown) for outputting a drive signal, and a ROM (not shown) in which a control program for controlling the timing of outputting the drive signal is stored. The PCM 6 is configured to control the operation of the engine 11 by outputting a drive signal from the main control unit to the injectors 4, 5 and the like based on a control program stored in the ROM. . The control program includes an activation temperature holding program which will be described later. The PCM 6 receives information on the catalyst temperature detected by the catalyst temperature detection means and the fuel selected by the fuel selection means, and selects one of the first fuel and the second fuel. The engine operation control means for controlling the operation of the engine 11 using the selected fuel as the fuel to be used is configured.

  Further, the PCM 6 selects hydrogen as the fuel to be used when the predetermined condition is satisfied, that is, until the catalyst temperature reaches the activation temperature TA for the first time when the engine 11 starts operating, except for when the predetermined condition is satisfied. Is configured so that the fuel selected by the fuel changeover switch 34 is used.

  Furthermore, the PCM 6 has a catalyst temperature that once exceeds the activation temperature TA (350 ° C. in the present embodiment) and is set to be equal to or higher than the activation temperature TA (370 in the present embodiment). When the engine 11 is stopped by the PCM 6 when it is determined that there is no request for operation of the engine 11, the engine 11 is operated in a different manner depending on the fuel selected by the fuel changeover switch 34. Control.

  That is, when the catalyst temperature detected by the catalyst temperature sensor 35 is equal to or higher than the first predetermined temperature T1 and the engine 11 is stopped, the PCM 6 selects gasoline by the fuel changeover switch 34 and the catalyst. When the temperature decreases to reach the first predetermined temperature T1, the activation temperature holding program stored in the ROM (not shown) of the PCM 6 is executed, and the temperature is set higher than the first predetermined temperature T1. While the engine 11 is forcibly operated even if there is no operation request until the second predetermined temperature T2 (400 ° C. in the present embodiment) is reached, the catalyst temperature is kept at the activation temperature TA or higher, while the fuel switch 34 When the hydrogen is selected by the above, even when the catalyst temperature decreases and reaches the second predetermined temperature T2, Without performing an activation temperature holding program is configured to prohibit the operation of the engine 11 (see FIGS. 6 and 7). In the following description, when the engine 11 is in a stopped state, the operation that is forcibly performed even if there is no operation request for the engine 11 is referred to as forced operation, and is performed when there is a request for operation of the engine 11. Driving is called re-driving. The operating conditions such as engine speed and throttle opening during the forced operation are set in advance in the design stage so that the catalyst temperature rises quickly. The statement for realizing is written.

  In other words, when the catalyst temperature detected by the catalyst temperature sensor 35 is equal to or higher than the first predetermined temperature T1 and the engine 11 is in a stopped state, the PCM 6 performs the gasoline switch by the fuel changeover switch 34. When the selected catalyst temperature decreases and reaches a first predetermined temperature T1 set to be equal to or higher than the activation temperature TA of the catalyst, the engine 11 is forcibly operated by executing the activation temperature holding program. While the activation temperature holding control is performed to keep the catalyst temperature at the activation temperature TA or higher, when hydrogen is selected by the fuel changeover switch 34, even when the catalyst temperature reaches the first predetermined temperature T1, It can be said that the activation temperature holding control is prohibited from being executed.

  Further, the PCM 6 prohibits the operation of the engine 11 without executing the activation temperature holding program (by prohibiting the execution of the activation temperature holding control), so that the catalyst temperature becomes the activation temperature TA. When it is lower, only the hydrogen selection button 34a is displayed on the display 74, and the gasoline selection button 34b is not displayed (see FIG. 5B). Thereby, it becomes impossible to select gasoline by the fuel changeover switch 34. That is, the selection of gasoline is prohibited by controlling the display of the fuel changeover switch 34 by the PCM 6 to hide the gasoline selection button 34b. The PCM 6 prohibits the selection of the first fuel by the fuel selection means when the catalyst temperature is lower than the activation temperature TA by prohibiting the execution of the activation temperature holding control. Will also be configured.

  Therefore, as shown in FIG. 6, when the catalyst temperature is reduced to the first predetermined temperature T1 because the engine 11 is stopped, the gasoline temperature is selected when the fuel changeover switch 34 selects gasoline. When the activation temperature holding control is executed, the engine 11 is heated by the forced operation of the engine 11 and rises from the first predetermined temperature T1 to the second predetermined temperature T2, and then the engine 11 is stopped to stop the first predetermined temperature T1. Then, the engine 11 is forcibly operated and then rises again to the second predetermined temperature T2. In this way, once the catalyst temperature reaches the first predetermined temperature T1, the forced operation and stop of the engine 11 are alternately repeated, whereby the first predetermined temperature T1 and the second predetermined temperature T2 are increased. Ascending and descending are repeated alternately. Therefore, once the catalyst temperature reaches the first predetermined temperature T1, it is always kept at the first predetermined temperature T1 or higher. When it is determined by the PCM 6 that there is an engine operation request, the engine 11 is restarted using gasoline, which is fuel selected by the fuel changeover switch 34 based on the occupant's intention, as the used fuel.

  On the other hand, as shown in FIG. 7, when the catalyst temperature is lowered to the first predetermined temperature T1 because the engine 11 is in a stopped state, when the hydrogen is selected by the fuel changeover switch 34, the activation temperature is increased. The holding control is not executed and the engine 11 is maintained in the stopped state. Therefore, the catalyst temperature continues to decrease further and eventually falls below the activation temperature TA. In the following description, when the activation temperature holding control is not performed, the time when the catalyst temperature is lower than the activation temperature TA is referred to as the time when the catalyst temperature decreases.

  Since the selection of gasoline by the fuel changeover switch 34 is prohibited as described above when the catalyst temperature drops, the engine 11 always uses hydrogen as the fuel to be used when the PCM 6 determines that there is an engine operation request. Re-operation is started. Then, after the catalyst temperature becomes equal to or higher than the activation temperature TA, the re-operation is continued using the fuel selected by the fuel changeover switch 34 as the used fuel. That is, since the selection of gasoline is prohibited when the catalyst temperature is lowered, the engine 11 does not supply hydrogen unless a new gasoline is selected by the fuel changeover switch 34 even after the catalyst temperature reaches the activation temperature TA. Forced operation continues as the fuel used. Then, after the catalyst temperature becomes equal to or higher than the activation temperature TA, when gasoline is selected by the fuel changeover switch 34, the fuel used is switched to gasoline and the forcible operation is performed. FIG. 7 shows a case where the engine temperature is requested and the engine 11 is restarted when the catalyst temperature is reduced to the steady temperature TS. For example, the catalyst temperature is the steady temperature. Similarly, when there is an engine operation request before reaching TS, the engine 11 may be restarted using hydrogen as a fuel.

  Next, specific processing operations regarding the selection of fuel used and engine operation control 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 whether or not the read catalyst temperature has reached the activation temperature TA, that is, whether or not the catalyst temperature is equal to or higher than the activation temperature TA. If the determination in step S4 is YES, the process proceeds to step S5. If NO, the process proceeds to step S6.

  In step S5, the fuel selected by the fuel changeover switch 34 is read and identified.

  In step S6, the fuel selected by the fuel changeover switch 34, that is, the fuel read in step S6 is selected (confirmed) as the used fuel.

  In step S7, which advances to NO in step S4, hydrogen is selected as the fuel used.

  In step S8, selection of gasoline by the fuel changeover switch 34 is prohibited. Specifically, only the hydrogen selection button 34 a is displayed on the display 74.

  On the other hand, in step S9, it is determined whether or not the engine 11 is in an operating state. If the determination in step S9 is YES, the process proceeds to step S10, where the engine 11 is stopped and the process returns. If the determination in step S9 is NO, the process returns with the engine 11 stopped.

  In step S10, the catalyst temperature is read again based on the detection signal from the catalyst temperature sensor 35.

  In step S11, it is determined whether or not the read catalyst temperature has reached the activation temperature TA, that is, whether or not the catalyst temperature is equal to or higher than the activation temperature TA. If the determination in step S11 is NO, step S11 is performed. While the process proceeds to S12, in the case of YES, the process proceeds to Step S13.

  In step S12, the engine 11 is stopped and the process returns.

  In step S13, which proceeds in the case of YES in step S11, the engine 11 is stopped.

  In step S14 (see FIG. 9), 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 changeover switch 34 are again displayed. Read.

  In step S15, it is determined whether or not there is an operation request for the engine 11. If the determination in step S15 is YES, the process returns. If NO, the process proceeds to step S16.

  In step S16, the catalyst temperature is read based on the detection signal from the catalyst temperature sensor 35.

  In step S17, it is determined whether or not the read catalyst temperature is equal to or lower than the first predetermined temperature T1. If the determination in step S17 is YES, the process proceeds to step S18. If NO, the process proceeds to step S14. Return.

  In step S18, it is determined whether or not gasoline is selected by the fuel changeover switch 34. If this determination is YES, the process proceeds to step S19, and if NO, the process proceeds to step S23.

  In step S19, the engine 11 is forcibly operated using gasoline as a used fuel.

  In step S20, the catalyst temperature is read again based on the detection signal from the catalyst temperature sensor 35.

  In step S21, it is determined whether or not the read catalyst temperature is equal to or higher than the second predetermined temperature T2. If this determination is NO, the process returns to step S20, and if YES, the process proceeds to step S22.

  In step S22, the engine 11 is stopped.

  On the other hand, in step S23 which proceeds to NO in step 18, it is determined whether or not the catalyst temperature is equal to or higher than the activation temperature TA. If this determination is YES, the process returns to step S14, whereas if NO, Proceed to step S24.

  In step S24, fuel selection by the fuel changeover switch 34 is prohibited. That is, only the hydrogen selection button 34 a is displayed on the display 74.

  As described above, in the first embodiment, the PCM 6 uses the fuel changeover switch 34 when the catalyst temperature detected by the catalyst temperature sensor 35 is equal to or higher than the first predetermined temperature T1 and the engine 11 is stopped. When it is determined that gasoline has been selected and the catalyst temperature has decreased to reach the first predetermined temperature T1 (NO in step S17), an activation temperature holding program stored in the ROM is stored. The catalyst temperature is maintained at the activation temperature TA or higher by forcibly operating the engine 11 using gasoline as a fuel until the second predetermined temperature T2 is reached (by executing the activation temperature holding control). Has been.

  As a result, when the engine is restarted, the catalyst temperature can be kept at the activation temperature TA or higher at all times, and therefore the exhaust gas caused by insufficient catalyst purification capacity because the catalyst temperature is below the activation temperature TA. Increase in emissions can be suppressed.

  In the first embodiment, the engine 11 is not continuously forcedly operated in order to keep the catalyst temperature at the activation temperature TA or higher. When the catalyst temperature reaches the second predetermined temperature T2, the engine 11 is stopped. The engine temperature is stopped and the engine 11 is repeatedly stopped and forcedly operated, so that the catalyst temperature is maintained at the activation temperature TA or higher. Therefore, it is possible to improve the fuel efficiency of the vehicle 1 by shortening the forced operation time of the engine 11.

  Further, in the first embodiment, the first predetermined temperature T1 is set to 370 ° C. higher than the activation temperature TA (350 ° C. in the present embodiment). Therefore, even if the timing for starting the forced operation of the engine 11 is slightly delayed, the engine 11 is forcibly operated before the catalyst temperature falls below the activation temperature TA to suppress the generation of the exhaust emission. it can.

  Furthermore, in the first embodiment, when the hydrogen is selected by the fuel changeover switch 34 (in the case of NO in step S18), the PCM 6 reduces the catalyst temperature to the first predetermined temperature T1. Even when it reaches, the engine 11 is maintained in the stopped state without executing the activation temperature holding program. Thereby, it is possible to prevent the operation of the engine 11 to heat the catalyst and to improve the fuel consumption even when hydrogen with less exhaust emission is used as the fuel.

  In the first embodiment, the PCM 6 displays only the hydrogen selection button 34a on the display 74 and does not display the gasoline selection button 34b when the catalyst temperature decreases (NO in step 23). It is configured as follows. Accordingly, it is possible to reliably prevent the gasoline selection button 34b from being selected when the catalyst temperature is lower than the activation temperature TA. Therefore, it is possible to prevent the exhaust emission from being increased by selecting gasoline as the fuel to be used when the engine 11 is restarted even though the catalyst temperature is lower than the activation temperature TA.

In the first embodiment, the PCM 6 is configured to use the fuel selected by the fuel changeover switch 34 as the used fuel when the catalyst temperature is equal to or higher than the activation temperature TA. 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. For example, when the occupant desires a running state in which torque is emphasized, the fuel changeover switch 34 may select gasoline having a larger output torque of the motor 17 than hydrogen.

(Embodiment 2)
FIG. 10 shows a second embodiment of the present invention, in which the operation control of the engine 11 performed when the catalyst temperature is lowered in the PCM 6 is different from that in the first embodiment. The configuration of the vehicle 1 such as the engine 11 and the motor 17 is the same as that in the first embodiment in the following embodiments. That is, the PCM 6 allows the engine 11 to be forcibly operated using hydrogen instead of gasoline as the fuel to be used when gasoline is selected, although the selection of gasoline by the fuel changeover switch 34 is allowed when the catalyst temperature is lowered. At the same time, the catalyst temperature is raised to the activation temperature TA, and after the catalyst temperature reaches the activation temperature TA, the forcible operation is performed using gasoline as the fuel used.

  Specifically, as shown in FIG. 10, when the gasoline temperature is selected by the fuel changeover switch 34 when the catalyst temperature is lowered, the engine 11 activates the catalyst temperature using hydrogen instead of gasoline as the used fuel. Forced operation is performed until the temperature TA is reached. Then, after the catalyst temperature reaches the activation temperature TA, the forced operation is continued using gasoline as the fuel to be used unless hydrogen is selected again by the fuel changeover switch 34. The catalyst temperature continues to rise further from the activation temperature TA and eventually reaches the first predetermined temperature T1, and then the activation temperature holding control of the engine 11 is executed, so that the catalyst temperature is always higher than the first predetermined temperature T1. (See FIG. 6). When the PCM 6 determines that there is an engine operation request when the catalyst temperature is equal to or higher than the activation temperature TA, the engine 11 starts re-operation using gasoline as a fuel.

  When the engine temperature is determined to be requested by the PCM 6 when the catalyst temperature is lower than the activation temperature TA, the engine 11 is restarted using hydrogen as a fuel until the catalyst temperature reaches the activation temperature TA. After the catalyst temperature reaches the activation temperature TA, re-operation is performed using gasoline as the fuel.

  Next, specific processing operations regarding the selection of fuel used and the engine operation control in the PCM 6 will be described with reference to FIG. In the steps from Step S1 to Step S13 (see FIG. 8), it is assumed that the same processing as that in the first embodiment is performed, and in the following description, the steps after Step S31 that proceed after Step S13 will be described. .

  In step S31, 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 changeover switch 34 are read again.

  In step S32, it is determined whether or not there is a request for driving the engine 11. If the determination in step S32 is YES, the process returns. If NO, the process proceeds to step S33.

  In step S33, the catalyst temperature is read.

  In step S34, it is determined whether or not the catalyst is at the first predetermined temperature T1 or less. If the determination in step S34 is YES, the process proceeds to step S35, whereas if NO, the process returns to step S31.

  In step S35, it is determined whether or not the catalyst is at an activation temperature TA or higher. If the determination in step S35 is YES, the process proceeds to step S36, and if NO, the process proceeds to step S41.

  In step S36, it is determined whether or not gasoline is selected by the fuel changeover switch 34. If the determination in step S36 is NO, the process returns to step S31, whereas if YES, the process proceeds to step S37.

  In step S37, the engine 11 is forcibly operated using gasoline as a used fuel.

  In step S38, the catalyst temperature is read again based on the detection signal from the catalyst temperature sensor 35.

  In step S39, it is determined whether or not the catalyst temperature is equal to or higher than the second predetermined temperature T2. If the determination in step S39 is NO, the process returns to step S38, whereas if YES, the process proceeds to step S40.

  In step S40, the engine 11 is stopped and the process returns to step S31.

  On the other hand, in step S41 which advances to NO in step S35, it is determined whether or not gasoline is selected by the fuel changeover switch 34. If this determination is NO, the process returns to step S31, whereas if YES, Proceed to step S42.

  In step S42, the engine 11 is forcibly operated using hydrogen as a used fuel.

  In step S43, the catalyst temperature is read based on the detection signal from the catalyst temperature sensor 35.

  In step S44, it is determined whether or not the catalyst temperature has reached the activation temperature TA, that is, whether or not the catalyst temperature is equal to or higher than the activation temperature TA. If this determination is YES, the process returns to step S31, and if NO, Returns to step S43.

  As described above, in the second embodiment, when the catalyst temperature is lowered (NO in step S35), the PCM 6 is selected when gasoline is selected by the fuel changeover switch 34 (YES in step 41). The engine 11 is forcibly operated using hydrogen as a fuel to increase the catalyst temperature to the activation temperature TA. Then, after the catalyst temperature further rises and reaches the first predetermined temperature T1, the activation temperature holding control is executed by the PCM 6 so that the catalyst temperature is always maintained at the first predetermined temperature T1 or higher. ing.

  Thus, when gasoline is selected by the fuel changeover switch 34 when the catalyst temperature is lowered, the catalyst temperature can be kept higher than the activation temperature TA when the engine 11 is restarted. The exhausted catalyst can be reliably purified by the activated catalyst. Further, until the catalyst temperature reaches the activation temperature TA, the engine 11 is forcibly operated using hydrogen as the fuel to be used, and therefore, the exhaust emission can be reduced as compared with the case where gasoline is used as the fuel.

(Embodiment 3)
FIG. 12 shows a third embodiment of the present invention, in which the operation control of the engine 11 performed when the catalyst temperature is lowered in the PCM 6 is different from that in the first embodiment. That is, when gasoline is selected by the fuel changeover switch 34 when the catalyst temperature is lowered, the PCM 6 maintains the engine 11 in a stopped state until it is determined by the PCM 6 that there is an engine operation request. When it is determined that there is an operation request, the engine 11 is restarted using hydrogen as a fuel until the catalyst temperature reaches the activation temperature TA, and after the activation temperature TA is reached (the activation temperature TA or higher). The engine 11 is restarted using gasoline as a fuel.

  In other words, the PCM 6 uses the fuel selected by the fuel changeover switch 34 when the catalyst temperature is higher than the activation temperature TA, while using hydrogen when the catalyst temperature is lower than the activation temperature TA. It is configured to use as fuel.

  Next, specific processing operations for selection of fuel used and engine operation control in the PCM 6 will be described with reference to FIG. In the steps from Step S1 to Step S13 (see FIG. 8), the same processing as that in the first embodiment is performed, and in the following description, the steps after Step S61 that proceed after Step S13 will be described. .

  In step S61, 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 changeover switch 34 are read again.

  In step S62, it is determined whether or not there is an operation request for the engine 11. If the determination in step 62 is YES, the process returns. If NO, the process proceeds to step 63.

  In step S63, the catalyst temperature is read based on the detection signal from the catalyst temperature sensor 35.

  In step S64, it is determined whether or not the catalyst temperature is equal to or lower than the first predetermined temperature T1, and if the determination in step 64 is YES, the process proceeds to step 65, whereas if NO, the process returns to step S61.

  In step S65, it is determined whether or not the catalyst temperature is equal to or higher than the activation temperature TA. If the determination in step 65 is NO, the process returns to step S61, whereas if YES, the process proceeds to step S66.

  In step S66, it is determined whether or not gasoline is selected by the fuel changeover switch 34. If the determination in step 66 is NO, the process returns to step S61, whereas if YES, the process proceeds to step S67.

  In step S67, the engine 11 is forcibly operated using gasoline as a used fuel.

  In step S68, the catalyst temperature is read again based on the detection signal from the catalyst temperature sensor 35.

  In step S69, it is determined whether or not the read catalyst temperature is equal to or higher than the second predetermined temperature T2. If the determination in step S69 is NO, the process returns to step S68, whereas if YES, the process proceeds to step S70.

  In step S70, the engine 11 is stopped and the process returns to step S61.

  As described above, in the third embodiment, when gasoline is selected by the fuel changeover switch 34 when the catalyst temperature is lowered, the engine 11 is kept stopped until it is determined by the PCM 6 that there is an engine operation request. At the same time, when it is determined that there is an engine operation request, the engine 11 is re-operated using hydrogen as a fuel until the catalyst temperature reaches the activation temperature TA, while gasoline is used after the activation temperature TA is reached. The engine 11 is re-operated using as fuel. As a result, while the engine 11 is restarted, torque shock due to switching of the fuel used from hydrogen to gasoline is slightly generated, but the catalyst is in an inactive state while the catalyst temperature is below the activation temperature TA. Sometimes the engine 11 can be restarted with hydrogen as the fuel used. Accordingly, it is possible to reliably reduce the exhaust emission as compared with the case where gasoline is used as the fuel in the inactive state.

(Other embodiments)
The configuration of the present invention is not limited to the above embodiment, but includes various other configurations. That is, in each of the above embodiments, a series hybrid vehicle is adopted as the vehicle 1 on which the dual fuel engine 11 is mounted. However, the present invention is not limited to this. For example, the vehicle 1 includes the engine 11 and the motor 17. It is good also as a parallel hybrid vehicle which is provided as a power source and moves with both these powers.

  Further, in each of the above embodiments, gasoline and hydrogen can be switched as the fuel to be used. However, the present invention is not limited to this. For example, natural gas may be used instead of hydrogen, or gasoline may be used instead. You may make it employ | adopt light oil.

  In each of the above embodiments, the fuel changeover switch 34 is configured by the touch panel 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 the 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 hybrid vehicle having a dual fuel that can be used by selectively switching between two used fuels, and particularly useful when the occupant has a fuel selection means that can select the used fuel. .

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 figure which shows an example of the change of the fuel switch displayed on the display of a navigation apparatus. When the engine is stopped and the catalyst temperature is equal to or higher than the first predetermined temperature, when gasoline is selected by the fuel changeover switch, the engine operation control performed by the powertrain control module is described. FIG. Explain the engine operation control performed by the powertrain control module when the engine is stopped and the catalyst temperature is higher than the first predetermined temperature and the catalyst temperature is lower than the activation temperature. It is the schematic for performing. It is a flowchart which shows the processing operation regarding engine operation control by a powertrain control module. It is a flowchart which shows the processing operation regarding engine operation control by a powertrain control module after a catalyst temperature becomes more than an activation temperature and an engine will be in a halt condition. FIG. 8 is a diagram corresponding to FIG. FIG. 10 is a diagram corresponding to FIG. FIG. 8 is a diagram corresponding to FIG. FIG. 10 is a diagram corresponding to FIG.

Explanation of symbols

1 Vehicle 6 Powertrain control module (Engine operation control means) (Operation request determination means)
(Prohibited means)
11 Dual fuel engine 17 Motor 34 Fuel changeover switch (fuel selection means)
35 Catalyst temperature sensor (catalyst temperature detection means)

Claims (5)

A dual fuel engine that can switch between a first fuel and a second fuel that has less exhaust emissions when the catalyst is inactive than the first fuel, and a motor that can output the driving force of the vehicle. A hybrid vehicle control device configured to be able to travel only with the driving force of the motor with the engine stopped.
Catalyst temperature detecting means for detecting the temperature of the catalyst;
Fuel selection means capable of selecting one of the first fuel and the second fuel by being operated by an occupant of the vehicle;
In response to information on the catalyst temperature detected by the catalyst temperature detection means and the fuel selected by the fuel selection means, one of the first fuel and the second fuel is selected and the selected fuel is selected. An engine operation control means for controlling the operation of the engine as a fuel to be used,
The engine operation control means includes the fuel selection means when the catalyst temperature detected by the catalyst temperature detection means is equal to or higher than a predetermined temperature set to be equal to or higher than the activation temperature of the catalyst and the engine is stopped. When the first fuel is selected by the above and the catalyst temperature detected by the catalyst temperature detecting means decreases and reaches the predetermined temperature, the engine is operated to keep the catalyst temperature above the activation temperature. On the other hand, when the second fuel is selected by the fuel selection means, the activation temperature holding control is prohibited even when the catalyst temperature reaches the predetermined temperature. The control apparatus of the hybrid vehicle characterized by the above-mentioned. In the hybrid vehicle control device according to claim 1,
The first fuel is gasoline,
The control apparatus for a hybrid vehicle, wherein the second fuel is hydrogen. In the control apparatus of the hybrid vehicle according to claim 1 or 2,
Fuel selection prohibiting means for prohibiting selection of the first fuel by the fuel selection means when the catalyst temperature is lower than the activation temperature due to prohibition of execution of the activation temperature holding control. A control device for a hybrid vehicle. In the control apparatus of the hybrid vehicle according to claim 1 or 2,
When the first fuel is selected by the fuel selection means when the catalyst temperature is lower than the activation temperature due to prohibition of the activation temperature holding control, the engine operation control means A control device for a hybrid vehicle, wherein the engine is operated using a second fuel as a fuel to be used, and the catalyst temperature is increased to an activation temperature or higher. In the control apparatus of the hybrid vehicle according to claim 1 or 2,
Comprising an operation request determination means for determining the presence or absence of an operation request of the engine,
When the first fuel is selected by the fuel selection means when the catalyst temperature is lower than the activation temperature due to prohibition of the activation temperature holding control, the engine operation control means The engine stop state is maintained until it is determined by the operation request determination means that an engine operation request is present, and when the engine request is determined by the operation request determination means, before the catalyst temperature reaches the activation temperature. The hybrid is characterized in that the engine is operated using the second fuel as a used fuel until the activation temperature is reached, and the engine is operated using the first fuel as a used fuel. Vehicle control device.

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