JP2007085203A - Control device of dual-fuel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a fuel from being shorted immediately after the fuel is switched from a gasoline to a gas fuel and switch the fuel with good response to a request for switching in a dual-fuel engine in which the gas fuel is switchable with the gasoline for the fuel to be used. <P>SOLUTION: This control device of the dual-fuel engine replenishes (S17) the gas fuel from a gas fuel tank to a gas fuel feed passage by opening the main valve of the gas fuel tank so that when the fuel to be used is the gasoline and the value on the replenishing amount of the gas fuel in the gas fuel feed passage (pressure of hydrogen as the gas fuel) is equal to or less than a predetermined value (0.3 MPa) (when the determination of S14 is YES), the value on the replenishing amount of the gas fuel is larger than a predetermined value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to a technical field related to a control device for a dual fuel engine that can switch between gaseous fuel and gasoline as fuel to be used.

  In recent years, from the viewpoint of environmental problems and the like, a dual fuel engine has been actively developed as an engine for vehicles such as automobiles. For example, as disclosed in Patent Document 1, this dual fuel engine is capable of switching between a gaseous fuel such as natural gas and gasoline as a used fuel. It is also known to use hydrogen as the gaseous fuel (see, for example, Patent Document 2).

  The gaseous fuel is normally stored in a gaseous fuel tank, and this gaseous fuel tank is provided with a main valve. The main valve is connected to an injector that supplies gaseous fuel to the combustion chamber of the engine via a gaseous fuel supply path. When the fuel used is gaseous fuel, the main valve is opened, and the gaseous fuel in the gaseous fuel tank is supplied to the combustion chamber of the engine via the gaseous fuel supply path and the injector. On the other hand, when the fuel used is gasoline, the main valve is closed. At this time, the gaseous fuel supply path is filled with the gaseous fuel, and when the used fuel is switched to the gaseous fuel next time, the gaseous fuel is immediately supplied to the combustion chamber of the engine. .

  However, the gaseous fuel in the gaseous fuel supply passage is little but leaks into the combustion chamber of the engine through the injector, and even if a shutoff valve is provided in the vicinity of the injector in the gaseous fuel supply passage, the leakage is completely prevented. It is difficult. For this reason, in particular, when switching to gaseous fuel after operating the engine for a long time using only gasoline, the gaseous fuel supply path is not sufficiently filled with gaseous fuel. If switching is performed in the state, fuel shortage occurs immediately after the switching, and the operability of the engine deteriorates.

Therefore, in Patent Document 1, when there is a request for switching from gasoline to gaseous fuel, the operability of the engine deteriorates immediately after switching by performing fuel switching after supplying gaseous fuel to the gaseous fuel supply path. I try to prevent it.
JP 2002-256914 A JP 2005-155528 A

  However, as in Patent Document 1, when there is a request for switching from gasoline to gaseous fuel, if the gaseous fuel is replenished to the gaseous fuel supply path, there is a problem that execution of switching is delayed by that amount. is there.

  The present invention has been made in view of such points, and an object of the present invention is to switch from gasoline to gaseous fuel in a dual fuel engine that can switch between gaseous fuel and gasoline as described above. It is intended to prevent a shortage of fuel immediately after execution and to perform switching with good response to a switching request.

  In order to achieve the above object, according to the present invention, when the fuel used is gasoline, the main valve is periodically opened to replenish the gaseous fuel from the gaseous fuel tank to the gaseous fuel supply path, or the gaseous fuel. When the value relating to the filling amount of the gaseous fuel in the supply passage is less than or equal to the predetermined value, the main valve is opened to remove the gaseous fuel from the gaseous fuel tank so that the value relating to the filling amount of the gaseous fuel becomes larger than the predetermined value. Was replenished to the gaseous fuel supply path.

  Specifically, the invention of claim 1 is directed to a control device for a dual fuel engine that can switch between gaseous fuel and gasoline as the fuel used.

  And a gas fuel tank for storing the gas fuel, a main valve provided in the gas fuel tank, which is opened when the fuel used is gas fuel, and is closed when the fuel used is gasoline, and the valve And a gas fuel supply passage for connecting the gas fuel to a combustion chamber of the engine, and when the fuel used is gasoline, the gas valve is opened periodically to open the gas fuel tank. Gas fuel replenishing means for replenishing the gaseous fuel to the gaseous fuel supply path.

  With the above configuration, when the fuel used is gasoline, even if the gaseous fuel in the gaseous fuel supply path leaks, the gas is periodically discharged from the gaseous fuel tank (for example, every predetermined time or every predetermined distance of the vehicle). Since the fuel is replenished to the gaseous fuel supply path, when there is a request for switching from gasoline to gaseous fuel, the gaseous fuel supply path is always sufficiently filled with gaseous fuel. Even when switching from gasoline to gaseous fuel is performed, there is no shortage of fuel immediately after this switching is performed, and the operability of the engine does not deteriorate.

  The invention of claim 2 is directed to a dual fuel engine control device mounted on a vehicle and capable of switching between gaseous fuel and gasoline as used fuel.

  And a gas fuel tank for storing the gas fuel, a main valve provided in the gas fuel tank, which is opened when the fuel used is gas fuel, and is closed when the fuel used is gasoline, and the valve And a gaseous fuel supply passage for connecting the gaseous fuel to the combustion chamber of the engine, and a filling amount related value detecting means for detecting a value related to the filling amount of the gaseous fuel in the gaseous fuel supply passage When the fuel used is gasoline, and the value relating to the filling amount of the gaseous fuel detected by the filling amount related value detecting means is not more than a predetermined value, the value relating to the filling amount of the gaseous fuel is Gas fuel replenishing means for opening the main valve and replenishing the gaseous fuel supply path with gaseous fuel from the gaseous fuel tank so as to be larger than the value. To.

  As a result, when the fuel used is gasoline, and the value related to the filling amount of the gaseous fuel in the gaseous fuel supply passage is equal to or less than a predetermined value, the gaseous fuel supply passage is sufficiently filled with the gaseous fuel. In this case, the value related to the filling amount of the gaseous fuel is larger than the predetermined value, that is, the gaseous fuel supply path is sufficiently filled with the gaseous fuel. Thus, since the gaseous fuel is replenished from the gaseous fuel tank to the gaseous fuel supply path, the switching from the gasoline to the gaseous fuel is executed immediately after the request for switching from the gasoline to the gaseous fuel as in the first aspect of the invention. However, there is no shortage of fuel immediately after the switching is performed, and the operability of the engine does not deteriorate.

  According to a third aspect of the present invention, in the second aspect of the invention, the pressure reducing means for depressurizing and supplying the gaseous fuel in the gaseous fuel tank to the gaseous fuel supply means in the vicinity of the main valve in the gaseous fuel supply path. A shutoff valve is provided in the vicinity of the gaseous fuel supply means in the gaseous fuel supply passage, which is closed when the fuel used is gasoline, and is opened when the fuel used is gaseous fuel. The related value detection means is configured to detect a pressure of the gaseous fuel in the gaseous fuel supply path between the pressure reducing means and the shutoff valve as a value related to a filling amount of the gaseous fuel in the gaseous fuel supply path. It is assumed that

  This makes it possible to reliably determine whether or not the gaseous fuel supply path is sufficiently filled with a simple configuration.

  According to a fourth aspect of the present invention, in the second or third aspect of the invention, the gas fuel replenishing means is configured to adjust the filling amount of the gaseous fuel detected by the filling amount related value detecting means when the fuel used is gasoline. When the gaseous fuel discharge speed from the gaseous fuel supply path, which is obtained from the change of the related value with respect to time, is greater than a predetermined speed, a value related to the gaseous fuel filling amount detected by the filling amount related value detecting means is predetermined. Even if the value is less than or equal to the value, it is assumed that the gaseous fuel supply passage is not replenished with gaseous fuel.

  That is, when the gaseous fuel discharge speed from the gaseous fuel supply path is higher than the predetermined speed, if the gaseous fuel is replenished to the gaseous fuel supply path, hydrogen is released again in a short time even if the gaseous fuel is replenished. This wastes gas fuel. However, according to the present invention, in such a case, since replenishment is not performed even if the value relating to the filling amount of the gaseous fuel in the gaseous fuel supply path is equal to or less than a predetermined value, wasteful consumption of gaseous fuel is performed. Can be suppressed.

  In the invention of claim 5, in the invention of claim 2 or 3, the current position detecting means for detecting the current position of the vehicle, the road information storing means for storing road information, and the current position detecting means Fuel switching means for switching the fuel used according to the current position of the vehicle, and the road stored by the road information storage means and the current position of the vehicle detected by the current position detecting means when the fuel used is gasoline. Switching predicting means for predicting that the fuel switching means switches the fuel to be used from gasoline to gaseous fuel when the vehicle travels a predetermined distance or less from the current position based on the information, The gaseous fuel replenishing means is configured such that when the fuel used is gasoline, the prediction by the switching predicting means is made and the filling amount is related. When values for loading of the gaseous fuel, which is detected by the detection means is below a predetermined value, it assumed to be configured to perform replenishment of gaseous fuel to the gas fuel supply passage.

  As a result, when the fuel to be used is automatically switched according to the current position of the vehicle, it is possible to predict in advance that there is a switch from gasoline to gaseous fuel, and the gas is pre- By replenishing the fuel supply path with gaseous fuel, it is possible to prevent fuel shortage from occurring immediately after execution of switching while suppressing wasteful consumption of gaseous fuel.

  As described above, according to the dual fuel engine control device of the present invention, when the fuel used is gasoline, the main valve is periodically opened to replenish gaseous fuel from the gaseous fuel tank to the gaseous fuel supply path. Alternatively, when the value related to the filling amount of the gaseous fuel in the gaseous fuel supply passage is equal to or less than the predetermined value, the main valve is opened so that the value relating to the filling amount of the gaseous fuel becomes larger than the predetermined value. By replenishing the gaseous fuel from the fuel tank to the gaseous fuel supply path, even if switching is performed immediately after the request for switching from gasoline to gaseous fuel, there will be no shortage of fuel immediately after this switching is performed. As a result, switching can be executed with good response to the switching request.

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

(Embodiment 1)
FIG. 1 schematically shows a configuration of a control device for a dual fuel engine according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a rotary engine. The rotary engine 1 is mounted on a vehicle such as an automobile, and can switch between gaseous fuel (hydrogen in this embodiment) and gasoline as the fuel used. It is considered as a dual fuel engine.

  The rotary engine 1 includes a rotor housing chamber (hereinafter referred to as a cylinder) 11 surrounded by a bowl-shaped rotor housing having a trochoid inner peripheral surface and a side housing, and a substantially triangular rotor 12 accommodated therein. In addition, three working chambers are defined on the outer peripheral side of the rotor 12. Although not shown, the rotary engine 1 is formed by integrating two rotor housings so as to be sandwiched between three side housings, and the rotors 12 and 12 are accommodated in two cylinders 11 and 11 formed therebetween, respectively. In FIG. 1, the two cylinders 11 and 11 are shown in an expanded state.

  Each of the rotors 12 rotates around the eccentric shaft 13 with the seal portions respectively disposed at the three tops of the outer periphery of the rotor 12 in contact with the inner peripheral surface of the trochoid of the rotor housing. Revolves around 13 axes. Then, while the rotor 12 makes one revolution, the working chambers formed between the tops of the rotor 12 move in the circumferential direction to perform intake, compression, expansion (combustion), and exhaust strokes. Is generated from the eccentric shaft 13 via the rotor 12.

  Each cylinder 11 of the rotary engine 1 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 11 is provided with two hydrogen injection injectors 4 for directly injecting hydrogen supplied from a hydrogen tank 31 (see FIG. 2) described later into the cylinder (in FIG. 1 and FIG. Each of the injectors 4 constitutes gas fuel supply means for supplying hydrogen as gaseous fuel to the combustion chamber (working chamber) of the engine 1. The two injectors 4 provided in each cylinder 11 are arranged in the axial direction of the eccentric shaft 13 in the vicinity of the long axis of the rotor housing.

  In addition, the intake passage 2 communicates with each cylinder 11 so as to communicate with the working chamber in the intake stroke, and the exhaust passage 3 communicates 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 11. Further, two exhaust passages 3 are provided on the upstream side so as to communicate with the working chambers of the respective cylinders 11, but are joined together on the downstream side. A three-way catalyst 25 as an exhaust purification catalyst for purifying exhaust gas is disposed downstream of the merging portion of the exhaust passage 3 (see FIG. 2).

  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 a later-described gasoline tank 41 (see FIG. 2) into the intake passage 2 (a branched portion) are disposed. ing.

  The ignition plugs 14, the actuators 21 of the throttle valves 22, and the injectors 4 and 5 for hydrogen and gasoline injection are controlled by a power train control module (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 12. Further, the actuator 21 of the throttle valve 22 is controlled by the PCM 6 in accordance with an output signal of an accelerator opening sensor (not shown) that detects the amount of depression of the accelerator pedal (accelerator opening) of the vehicle occupant. Adjust the opening. That is, the opening value of the throttle valve 22 corresponds to the output value of the throttle opening sensor (in this embodiment, which is also the actuator 21) for detecting the opening degree. To adjust to a predetermined value. Further, the injector 4 for hydrogen injection injects hydrogen into the cylinder 11 (working chamber) at a predetermined timing according to the rotational position of the rotor 12 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 12 when the fuel used is gasoline.

  FIG. 2 schematically shows the configuration of an intake system, an exhaust system, and a fuel supply system for the rotary engine 1. In FIG. 2, 31 is a hydrogen tank as a gaseous fuel tank that stores hydrogen therein, and 41 is a gasoline tank that contains gasoline therein. The hydrogen tank 31 is provided with a main valve 31a that is opened and closed by a main valve actuator 61 (see FIG. 1). The main valve 31a and each of the hydrogen injectors 4 are connected to a gaseous fuel supply path. They are connected by a hydrogen supply pipe 32 constituting the same. The gasoline tank 41 and the gasoline injectors 5 are connected by a gasoline supply pipe 42. In the present embodiment, the pressure in the hydrogen tank 31 is set to 36 MPa.

  The main valve 31a of the hydrogen tank 31 is opened when the fuel used is hydrogen, and is closed when the fuel used is gasoline. When the main valve 31a is closed, the hydrogen supply from the hydrogen tank 31 to the hydrogen supply pipe 32 is not performed. When the main valve 31a is opened, the hydrogen supply from the hydrogen tank 31 to the hydrogen supply pipe 32 is not performed. Made.

  A shutoff valve 33 that is opened and closed by a shutoff valve actuator 62 (see FIG. 1) is disposed in the vicinity of the injector 4 in the hydrogen supply pipe 32. This shutoff valve 33 is also the same as the main valve 31a. It is opened when the fuel used is hydrogen, and closed when the fuel used is gasoline. When the shut-off valve 33 is closed, hydrogen is not supplied from the hydrogen supply pipe 32 to the injector 4, and when the shut-off valve 33 is opened, hydrogen is supplied from the hydrogen supply pipe 32 to the injector 4. . However, even if the shut-off valve 33 is closed, it cannot be completely shut off, and hydrogen is slightly leaked (released) into the injector 4, and the injector 4 cannot completely shut off hydrogen. Therefore, hydrogen leaks into the combustion chamber of the engine 1.

  Further, a regulator (pressure reducing valve) 34 is provided in the vicinity of the main valve 31 a in the hydrogen supply pipe 32, and the hydrogen in the hydrogen tank 31 is reduced by the regulator 34 (the main pressure is reduced). In the embodiment, the pressure is reduced from 36 MPa to 0.6 MPa), and is supplied to the injector 4 via the hydrogen supply pipe 32. Thus, the regulator 34 constitutes a decompression means for decompressing the hydrogen in the hydrogen tank 31 and supplying it to the injector 4.

  A pressure sensor 35 is disposed in the hydrogen supply pipe 32 between the regulator 34 and the shutoff valve 33. The pressure sensor 35 detects the pressure of hydrogen in the hydrogen supply pipe 32 between the regulator 34 and the shutoff valve 33. Since the hydrogen pressure increases as the hydrogen filling amount in the hydrogen supply pipe 32 increases, the hydrogen pressure is a value relating to the hydrogen filling amount in the hydrogen supply pipe 32. Thus, the pressure sensor 35 constitutes a filling amount related value detecting means for detecting a value related to the filling amount of the gaseous fuel in the gaseous fuel supply passage.

  In addition to the signals necessary for controlling the operation of the ignition plugs 14, the actuators 21 of the throttle valves 22 and the injectors 4 and 5 for hydrogen and gasoline injection, the PCM 6 includes at least the above-mentioned signals as shown in FIG. Each output signal of the GPS sensor 51 as current position detecting means for receiving the GPS signal transmitted from the pressure sensor 35 and the GPS artificial satellite and detecting the current position of the vehicle is input.

  The PCM 6 includes a pressure sensor 35 and a GPS sensor 51, as will be described in detail later, in addition to the operation control of the ignition plugs 14, the actuator 21 of the throttle valve 22, and the injectors 4 and 5 for hydrogen and gasoline injection. Based on each output signal, the main valve actuator 61 and the shutoff valve actuator 62 are controlled to switch the fuel used, and when the fuel used is gasoline, the main valve actuator 61 is controlled, Hydrogen is supplied from the hydrogen tank 31 to the hydrogen supply pipe 32.

The fuel used for the engine 1 is hydrogen when the current position of the vehicle is within a predetermined CO ₂ and NO _x emission control area (for example, in a specific urban area), and gasoline when it is outside the emission control area. And In other words, when the vehicle goes out of the emission control area from outside the emission control area, the fuel used is automatically switched from hydrogen to gasoline. To automatically switch to. The PCM 6 determines whether or not the vehicle exists within the emission control area based on the output signal of the GPS sensor 53. Thus, the PCM 6 constitutes a fuel switching means for switching the fuel to be used according to the current position of the vehicle detected by the GPS sensor 51.

  When the fuel is switched, if the gasoline is injected into the intake passage 2 by the gasoline injection injector 5, the gasoline injection is stopped, and then the main valve 31a and the shutoff valve 33 are stopped. Is opened, and when hydrogen is injected into the cylinder 11 by the injector 4 for hydrogen injection and hydrogen is injected by the injector 4 for hydrogen injection, after the hydrogen injection is stopped, the main valve 31a And the shutoff valve 33 is closed, and gasoline is injected by the injector 5 for gasoline injection. When the fuel used is gasoline, hydrogen is filled in the hydrogen supply pipe 32 between the main valve 31a and the shut-off valve 33 that are closed together, and immediately after switching from hydrogen to gasoline. The pressure detected by the pressure sensor 35 is 0.6 MPa. However, as described above, even if the shutoff valve 33 is closed, the hydrogen in the hydrogen supply pipe 32 leaks into the combustion chamber of the injector 4 or the engine 1 and is released, so that gasoline is continuously used. As the time elapses, the hydrogen filling amount in the hydrogen supply pipe 32 decreases, and the pressure detected by the pressure sensor 35 also decreases. In the present embodiment, when this pressure becomes 0.3 MPa or less, the next time the switching from gasoline to hydrogen is performed, there is a high possibility that fuel shortage will occur immediately after the switching and the operability of the engine will deteriorate. Become. Therefore, in order to prevent such a shortage of fuel immediately after switching, when the pressure becomes 0.3 MPa or less, hydrogen is supplied from the hydrogen tank 31 to the hydrogen supply pipe 32.

  Specifically, the PCM 6 is configured such that when the fuel used is gasoline, the hydrogen pressure in the hydrogen supply pipe 32 detected by the pressure sensor 35 is a predetermined value (0.3 MPa in this embodiment) or less. At some time, the main valve actuator 61 is operated to open the main valve 31a, so that hydrogen is replenished from the hydrogen tank 31 to the hydrogen supply pipe 32, and the hydrogen pressure detected by the pressure sensor 35 is greater than the predetermined value. (In this embodiment, the pressure is set to 0.6 MPa, which is the same as that immediately after switching from hydrogen to gasoline). As a result, the PCM 6 also constitutes a gaseous fuel replenishing means.

  However, the PCM 6 determines that the hydrogen pressure is 0.3 MP or less when the hydrogen release rate from the hydrogen supply pipe 32 obtained from the change with respect to time of the hydrogen pressure detected by the pressure sensor 35 is higher than a predetermined rate. Also, the hydrogen supply pipe 32 is not replenished with hydrogen. That is, in this embodiment, hydrogen is normally released from the hydrogen supply pipe 32 at a hydrogen release rate such that the hydrogen pressure becomes 0.6 MPa to 0.3 MPa in about 60 minutes. The hydrogen release rate at which the hydrogen pressure is changed from 0.6 MPa to 0.3 MPa in minutes is set as the predetermined rate, and when hydrogen is released at a rate larger than the predetermined rate, it can be determined that there is an abnormality. If replenishment is performed during such an abnormality, hydrogen will be consumed wastefully, so that replenishment is not performed.

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

First, in the first step S1, the output signal (GPS information) of the GPS sensor 53 and the information on the currently used fuel are input. In the next step S2, the current position of the vehicle is determined based on the GPS information. determines whether the emissions regulations in the area of ₂ and NO _x. When the determination in step S2 is YES, the process proceeds to step S3. When the determination in step S2 is NO, the process proceeds to step S6.

  In step S3, which proceeds when the determination in step S2 is YES, it is determined whether or not the currently used fuel is hydrogen. When the determination in step S3 is YES, the process proceeds to step S4 and hydrogen is supplied. On the other hand, if the determination in step S3 is NO, the process proceeds to step S5, the fuel is switched from gasoline to hydrogen, and then the process returns.

  On the other hand, in step S6 that proceeds when the determination in step S2 is NO, it is determined whether or not the currently used fuel is gasoline. When the determination in step S6 is YES, the process proceeds to step S7. On the other hand, if the determination is NO in Step S6, the process proceeds to Step S8, the fuel is switched from hydrogen to gasoline, and then the process returns.

  When the fuel switching from hydrogen to gasoline is executed, the hydrogen replenishment process shown in FIG. 4 starts separately from the fuel switching process shown in FIG.

  That is, in the first step S11 of the hydrogen replenishment process, a timer is set and started, and in the next step S12, the output value α of the pressure sensor 35 is input.

  In the next step S13, it is determined whether or not the current fuel is gasoline. If the determination in step S13 is NO, the hydrogen replenishment process is terminated, while if the determination in step S13 is YES. The process proceeds to step S14.

  In step S14, it is determined whether or not α ≦ 0.3 MPa is satisfied. When the determination in step S14 is NO, the process returns to step S12. On the other hand, when the determination in step S14 is YES, the process returns to step S15. move on.

  In the step S15, the measurement time T of the set timer is read. In the next step S16, it is determined whether or not T ≧ predetermined time (20 minutes) is satisfied. If the determination in step S16 is NO, While this hydrogen replenishment process is complete | finished, when determination of step S16 is YES, it progresses to step S17.

  In step S17, an open command is output to the main valve actuator 61 until the value of α reaches 0.6 MPa. When the value of α reaches 0.6 MPa, the valve closes to the main valve actuator 61 in the next step S18. The command is output, and thereafter, the process returns to step S11, the timer is reset, and the processing operations after step S12 are repeated.

  When the vehicle enters the emission control area from outside the emission control area where gasoline was used as fuel by the processing operation of the PCM 6, the fuel used is switched from gasoline to hydrogen. Further, when the vehicle goes out of the emission control area where hydrogen is used as fuel, the fuel used is switched from hydrogen to gasoline.

  When the fuel used is gasoline (when the vehicle is traveling outside the emission regulation area), the pressure α (the pressure of hydrogen in the hydrogen supply pipe 32) detected by the pressure sensor 35 is 0.3 MPa or less. Then, it is determined whether or not the measurement time T of the timer (that is, the time until the pressure α becomes 0.6 MPa to 0.3 MPa) is 20 minutes (the predetermined time) or more.

  When the measurement time T is 20 minutes or more, that is, when hydrogen is released at a rate equal to or lower than the hydrogen release rate (predetermined rate) such that the hydrogen pressure changes from 0.6 MPa to 0.3 MPa in 20 minutes, the pressure α The main valve 31a is opened and hydrogen is supplied from the hydrogen tank 35 to the hydrogen supply pipe 32 so that the pressure becomes 0.6 MPa. When this replenishment is completed, the main valve 31a is closed, and then the timer is reset. When the pressure α becomes 0.3 MPa or less again, it is determined whether or not the measurement time T of the timer is 20 minutes or more. If it is 20 minutes or longer, the hydrogen supply pipe 32 is replenished with hydrogen again, and the above operation is repeated until the fuel used is switched from gasoline to hydrogen.

  On the other hand, when the measured time T of the timer is shorter than 20 minutes, that is, when hydrogen is released at a rate greater than the predetermined rate, the hydrogen replenishment process is terminated, and thus the pressure α is 0.3 MPa or less. However, the hydrogen supply pipe 32 is not replenished with hydrogen.

  In addition, when the fuel used is switched from gasoline to hydrogen, the hydrogen replenishment process ends. However, at the time of this switching, the hydrogen supply pipe 32 is always kept except during an abnormal time when the hydrogen release rate is greater than a predetermined rate. The hydrogen pressure is higher than 0.3 MPa, so that there is no shortage of fuel immediately after switching.

  Therefore, in this embodiment, when the fuel used is gasoline, when hydrogen in the hydrogen supply pipe 32 leaks and the hydrogen pressure becomes 0.3 MPa or less, the hydrogen supply pipe 32 is replenished with hydrogen. Therefore, the fuel to be used is not switched from gasoline to hydrogen when the hydrogen pressure is 0.3 MPa or less, and is always switched while the hydrogen supply pipe 32 is sufficiently filled with hydrogen. As a result, fuel shortage does not occur immediately after the switching, and the operability of the engine does not deteriorate. Therefore, it is possible to execute the switching with a good response to the switching request according to the current position of the vehicle, and when the vehicle enters the emission regulation area, it is possible to immediately switch the fuel to be used from gasoline to hydrogen.

  Further, when the hydrogen release speed from the hydrogen supply pipe 32 is higher than a predetermined speed, the hydrogen supply pipe 32 is not replenished with hydrogen, so that wasteful consumption of hydrogen can be suppressed.

(Embodiment 2)
In the present embodiment, when the fuel used is gasoline, it is predicted that the fuel used is switched from gasoline to hydrogen when the vehicle travels a predetermined distance or less from the current position detected by the GPS sensor 61. In addition, when the hydrogen pressure detected by the pressure sensor 35 is equal to or less than a predetermined value (also in this embodiment, 0.3 MPa as in the first embodiment), the hydrogen supply pipe 32 is replenished with hydrogen. It is what I did. The configuration of the rotary engine 1 and the intake system, exhaust system, and fuel supply system for the engine 1 are the same as those in the first embodiment.

  That is, in this embodiment, the vehicle is equipped with a navigation device having a storage unit (hard disk or the like) as road information storage means for storing road information, and this road information is input to the PCM 6. ing. The PCM 6 uses the current position of the vehicle detected by the GPS sensor 61 and the road information stored by the storage unit when the fuel used is gasoline (when the vehicle is traveling outside the emission regulation area). Based on the above, the distance of the shortest route from the current position to the emission control area is calculated. It is predicted that the fuel used will be switched from gasoline to hydrogen when only running. Thus, the PCM 6 constitutes a switching prediction unit. The PCM 6 replenishes the hydrogen supply pipe 32 with hydrogen when the above prediction is made and the hydrogen pressure detected by the pressure sensor 35 is 0.3 MPa or less.

  A specific processing operation in the PCM 6 will be described with reference to FIG. The fuel cut-off process is the same as that in the first embodiment. When the fuel switch from hydrogen to gasoline is executed, the hydrogen replenishment process shown in FIG. 5 starts separately from the fuel switch process.

  In the first step S21, the output signal (GPS information) of the GPS sensor 53, the road information stored in the storage unit of the navigation device, the information on the currently used fuel, and the output value α of the pressure sensor are input, and the next step S22. Then, it is determined whether or not the currently used fuel is gasoline. If the determination in step S22 is NO, the process returns as it is, while if the determination in step S22 is YES, the process proceeds to step S23.

  In step S23, the distance β of the shortest route from the current position of the vehicle to the emission control area is calculated based on the GPS information and road information, and in the next step S24, it is determined whether or not β ≦ 1 km is satisfied. To do. When the determination at step S24 is NO, the process returns as it is, while when the determination at step S24 is YES, the process proceeds to step S25.

  In step S25, it is determined whether or not α ≦ 0.3 MPa is satisfied. If the determination in step S25 is NO, the process returns as it is. If the determination in step S25 is YES, the process proceeds to step S26.

  In step S26, an open command is output to the main valve actuator 61 until the value of α reaches 0.6 MPa. When the value of α reaches 0.6 MPa, the valve closes to the main valve actuator 61 in the next step S27. A command is output, and then the process returns to step S23. Thereafter, the determination in step S25 is normally NO and the process returns.

  As a result of the processing operation of the PCM 6, when the vehicle is traveling outside the emission control area where gasoline is used as the fuel, if the distance β of the shortest route to the emission control area is within 1 km, the fuel used is gasoline. If the hydrogen pressure α in the hydrogen supply pipe 32 is 0.3 MPa or less, the main valve 31a is opened so that the pressure α is 0.6 MPa. Then, hydrogen is replenished from the hydrogen tank 35 to the hydrogen supply pipe 32.

  Therefore, in this embodiment, when the vehicle has traveled a predetermined distance or less from the current position detected by the GPS sensor 61, the fuel used is predicted to be switched from gasoline to hydrogen and detected by the pressure sensor 35. When the hydrogen pressure is 0.3 MPa or less, the hydrogen supply pipe 32 is replenished with hydrogen, so that the hydrogen supply pipe 32 is replenished in advance at a position before the change of the fuel used. Therefore, it is possible to prevent a shortage of fuel from occurring immediately after execution of switching while suppressing wasteful consumption of hydrogen.

(Embodiment 3)
In this embodiment, instead of detecting the hydrogen pressure in the hydrogen supply pipe 32 as in the first and second embodiments, the main valve 31a is opened periodically to supply hydrogen from the hydrogen tank 31 to the hydrogen supply pipe 32. It is intended to be replenished. The configurations of the rotary engine 1, the intake system, the exhaust system, and the fuel supply system for the engine 1 are the same as those in the first and second embodiments (however, the pressure sensor 35 may not be provided).

  That is, in this embodiment, the PCM 6 operates the main valve actuator 61 every predetermined time to open the main valve 31a for a predetermined time. This predetermined time is set to a time during which the hydrogen pressure in the hydrogen supply pipe 32 is changed from 0.6 MPa to 0.3 MPa, that is, 60 minutes. Further, the above-mentioned certain time during which the main valve 31a is opened is set to a time (which should be experimentally examined in advance) when the hydrogen pressure is replenished from 0.3 MP to 0.6 MPa when the hydrogen supply pipe 32 is replenished with hydrogen. To do.

  A specific processing operation in the PCM 6 will be described with reference to FIG. The fuel switching process is the same as in the first and second embodiments. When the fuel switching from hydrogen to gasoline is executed, the hydrogen replenishment process shown in FIG. 6 starts separately from the fuel switching process.

  In the first step S41, a timer is set and started. In the next step S42, it is determined whether or not the current fuel is gasoline. If the determination in step S42 is NO, the hydrogen replenishment process is performed. On the other hand, when the determination in step S42 is YES, the process proceeds to step S43.

  In step S43, it is determined whether or not 60 minutes have elapsed from the start of the timer. If the determination in step S43 is NO, the process returns to step S42. If the determination in step S43 is YES, step S44 is performed. Then, an open command is output to the main valve actuator 61 for a certain period of time, and a close command is output to the main valve actuator 61 in the next step S45. Thereafter, the process returns to step S41 and a timer is set. The processing operation after step S42 is repeated.

  Therefore, in the present embodiment, the main valve 31a is opened every predetermined time so that hydrogen is replenished from the hydrogen tank 31 to the hydrogen supply pipe 32. Therefore, as in the first and second embodiments, gasoline to hydrogen is supplied. At the time of switching, the hydrogen supply pipe 32 is sufficiently filled with hydrogen, and fuel shortage does not occur immediately after the switching, so that the operability of the engine does not deteriorate. Therefore, when the vehicle enters the emission regulation area, the fuel to be used can be switched from gasoline to hydrogen immediately. Further, the pressure sensor 35 as in the first and second embodiments is not necessary, and hydrogen replenishment can be performed with a simple configuration.

  In the third embodiment, the main valve 31a is opened every predetermined time so that hydrogen is supplied from the hydrogen tank 31 to the hydrogen supply pipe 32. However, the main valve 31a is opened every time the vehicle travels a predetermined distance. Hydrogen may be replenished from the tank 31 to the hydrogen supply pipe 32.

  In the first and third embodiments, the fuel used is switched according to the current position of the vehicle. However, the conditions for switching the fuel used may be any. For example, when the temperature of the catalyst falls below the threshold value from a state higher than a threshold value (temperature at which the catalyst is activated), or when the catalyst temperature becomes higher than the threshold value from a state below the threshold value, For example, when the driving state of the vehicle becomes a predetermined state. Alternatively, instead of automatically switching the fuel used, a vehicle occupant may be able to instruct the switching by a switch operation or the like.

  Further, in the first to third embodiments, the present invention is applied to the rotary engine 1 that can switch between hydrogen and gasoline as the fuel to be used, but a dual fuel engine that can switch between gas fuel such as natural gas and gasoline. The present invention can be applied to (not limited to a rotary engine).

  INDUSTRIAL APPLICABILITY The present invention is useful for a dual fuel engine control device that can switch between gaseous fuel and gasoline as the fuel used.

It is a schematic block diagram which shows the control apparatus of the dual fuel engine which concerns on Embodiment 1 of this invention. It is a schematic block diagram which shows the intake system with respect to the said engine, an exhaust system, and a fuel supply system. It is a flowchart which shows the fuel switching process operation | movement in a powertrain control module. It is a flowchart which shows the hydrogen replenishment process operation | movement in a powertrain control module. FIG. 5 is a diagram corresponding to FIG. 4 in the second embodiment. FIG. 5 is a diagram corresponding to FIG. 4 in the third embodiment.

Explanation of symbols

1 Rotary engine (dual fuel engine)
4 Injector for hydrogen injection (gaseous fuel supply means)
6 Powertrain control module
(Gaseous fuel replenishment means) (Fuel switching means) (Switching prediction means)
31 Hydrogen tank (gaseous fuel tank)
31a Main valve 32 Hydrogen supply pipe (gaseous fuel supply path)
33 Shutoff valve 34 Regulator (pressure reduction means)
35 Pressure line sensor (filling quantity related value detection means)
51 GPS sensor (current position detection means)

Claims (5)

A control device for a dual fuel engine that can switch between gaseous fuel and gasoline as the fuel used,
A gaseous fuel tank for storing the gaseous fuel;
A main valve provided in the gaseous fuel tank and opened when the used fuel is gaseous fuel, and closed when the used fuel is gasoline;
A gas fuel supply path connecting the main valve and a gas fuel supply means for supplying the gas fuel to the combustion chamber of the engine;
A dual fuel supply means for periodically opening the main valve and replenishing the gaseous fuel supply path with gaseous fuel from the gaseous fuel tank when the fuel used is gasoline; Fuel engine control device. A control device for a dual fuel engine mounted on a vehicle and capable of switching between gaseous fuel and gasoline as fuel used,
A gaseous fuel tank for storing the gaseous fuel;
A main valve provided in the gaseous fuel tank and opened when the used fuel is gaseous fuel, and closed when the used fuel is gasoline;
A gas fuel supply path connecting the main valve and a gas fuel supply means for supplying the gas fuel to the combustion chamber of the engine;
Filling amount related value detecting means for detecting a value related to the filling amount of the gaseous fuel in the gaseous fuel supply path;
When the fuel used is gasoline, when the value relating to the filling amount of the gaseous fuel detected by the filling amount related value detecting means is less than or equal to a predetermined value, the value relating to the filling amount of the gaseous fuel is less than the predetermined value. And a gas fuel replenishing means for replenishing gaseous fuel from the gaseous fuel tank to the gaseous fuel supply path by opening the main valve so as to be larger. The control apparatus for a dual fuel engine according to claim 2,
Pressure reducing means for reducing the pressure of the gaseous fuel in the gaseous fuel tank and supplying it to the gaseous fuel supply means is provided in the vicinity of the main valve in the gaseous fuel supply path,
In the vicinity of the gaseous fuel supply means in the gaseous fuel supply path, there is provided a shut-off valve that is closed when the used fuel is gasoline, and is opened when the used fuel is gaseous fuel,
The filling amount related value detecting means detects the pressure of the gaseous fuel in the gaseous fuel supply passage between the pressure reducing means and the shutoff valve as a value relating to the filling amount of the gaseous fuel in the gaseous fuel supply passage. The dual fuel engine control device is configured as described above. The dual fuel engine control device according to claim 2 or 3,
The gaseous fuel replenishing means is obtained from the gaseous fuel supply path obtained from a change with respect to time of a value related to the filling amount of the gaseous fuel detected by the filling amount related value detecting means when the fuel used is gasoline. When the gas fuel discharge speed of the gas fuel is larger than the predetermined speed, even if the value related to the amount of gaseous fuel detected by the filling quantity related value detecting means is less than or equal to the predetermined value, A control device for a dual fuel engine, characterized in that the refueling is not performed. The dual fuel engine control device according to claim 2 or 3,
Current position detecting means for detecting the current position of the vehicle;
Road information storage means for storing road information;
Fuel switching means for switching the fuel to be used according to the current position of the vehicle detected by the current position detecting means;
When the fuel used is gasoline, based on the current position of the vehicle detected by the current position detection means and the road information stored by the road information storage means, the vehicle is a predetermined distance from the current position. Switching prediction means for predicting that the fuel switching means is switched from gasoline to gaseous fuel by the fuel switching means when traveling for the following distance,
When the fuel used is gasoline, the gas fuel replenishing means performs the prediction by the switching prediction means, and the value related to the filling amount of the gaseous fuel detected by the filling amount related value detecting means is less than a predetermined value. A control device for a dual fuel engine, characterized in that, at a given time, the gaseous fuel supply passage is replenished with gaseous fuel.

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