JP2004068633A - Vehicle mounted gaseous fuel supply device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle mounted gaseous fuel supply device of an internal combustion engine capable of suitably reducing discomfort, etc., owing to the opening and closing movement of a shut-off valve. <P>SOLUTION: The device is provided with two fuel supply systems 2a and 2b comprising two fuel gas cylinders 8a and 8b storing gaseous fuel (compressed natural gas), and high pressure piping 12a and 12b and low pressure piping 14a and 14b provided corresponding to the gaseous cylinders 8a and 8b, respectively. The device is provided with a communicating pipe 24 communicating between each of fuel supply systems 2a and 2b and the shut-off valve 26 prepared in the middle of the communicating pipe 24. The shut-off valve 26 is opened and closed depending on a driving signal generated with a suitable timing to supply the fuel in each of gaseous cylinders 8a and 8b into each cylinder of the internal combustion engine 4 via each of fuel supply systems 2a and 2b. The opening and closing of the shut-off valve 26 are prohibited to drive when the background noise of the vehicle 1 is monitored, and the monitored background is less than a predetermined level. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gaseous fuel supply device for an in-vehicle internal combustion engine, and more particularly, to a device having a shutoff valve for switching between communication and shutoff between fuel supply systems when supplying fuel to the in-vehicle internal combustion engine through a plurality of fuel supply systems.
[0002]
[Prior art]
In recent years, an internal combustion engine using a gaseous fuel such as CNG (compressed natural gas) has been proposed and put into practical use. In such an internal combustion engine, gaseous fuel is compressed and stored in a fuel cylinder, and during operation of the engine, gaseous fuel is supplied from the fuel cylinder to a fuel injection valve provided in a cylinder head or the like of the internal combustion engine via a fuel supply pipe. Supplying.
[0003]
Here, since the fuel cylinder must store gaseous fuel, a large volume is generally required. For this reason, for example, when the installation space of the fuel cylinder is limited, such as when applied to an in-vehicle internal combustion engine, by providing a plurality of fuel cylinders, the installation space, and thus the capacity thereof, is secured. (See, for example, JP-A-8-158950).
[0004]
Further, when such an apparatus having a plurality of fuel cylinders is applied to an internal combustion engine divided into two banks, such as a V-type engine, a dedicated fuel cylinder is connected to each bank, and the fuel It has been proposed to supply gaseous fuel to each bank separately from cylinders. By using independent gaseous fuel supply systems in this way, even if an abnormality occurs in one gaseous fuel supply system, the combustion of the corresponding bank is stopped, but the other gaseous fuel supply system is stopped. Depending on the system, it is possible to continue operation in another bank. Accordingly, in this case, the internal combustion engine does not completely stop, and evacuation traveling to a repair shop or the like can be performed.
[0005]
However, in such a device, there is a difference in the capacity of the fuel cylinder due to the arrangement space, etc., and a difference in the amount of fuel injected into the fuel cylinder. May occur. In such a case, if the gaseous fuel supply system is independent for each bank, the fuel in one of the fuel cylinders runs out first, and the other fuel cylinder still has fuel. . For this reason, even though fuel remains in one of the fuel cylinders, one of the banks stops even though it is not a failure, so that the engine output is reduced and normal operation is hindered. Become.
[0006]
Therefore, conventionally, in order to suppress such inconveniences, there has been proposed an apparatus provided with a communication pipe for communicating two gaseous fuel supply systems and a shutoff valve for opening and closing the communication pipe. In this device, for example, when the pressure difference between the gaseous fuel supply systems becomes equal to or higher than a predetermined pressure, the shutoff valve is opened. This allows the gaseous fuel supply systems to communicate with each other and allow the gaseous fuels to move to each other, so that the fuels can be exchanged between the gaseous fuel supply systems and used up to the end.
[0007]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional apparatus, the shut-off valve is disposed in a portion filled with high-pressure fuel. Therefore, in order to operate such a shutoff valve quickly against the pressure of the fuel, a shutoff valve having a large driving force must be used. Such a shut-off valve having a large driving force inevitably generates a large operating noise. Therefore, if the shut-off valve is operated during operation of the vehicle, the operating noise is transmitted into the passenger compartment to make the driver uncomfortable. It also causes inconvenience such as giving.
[0008]
The gas fuel supply device is not limited to the gas fuel supply device that individually supplies gas fuel to the above-described banks, but includes a communication pipe that communicates with each fuel supply system and a shutoff valve that opens and closes the communication pipe. In fact, these facts are generally common.
[0009]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gaseous fuel supply device for a vehicle-mounted internal combustion engine that can appropriately alleviate discomfort or the like caused by the opening and closing operation of a shutoff valve. It is in.
[0010]
[Means for Solving the Problems]
Hereinafter, the means for achieving the above object and the effects thereof will be described.
First, the invention according to claim 1 provides a plurality of fuel supply systems including a plurality of fuel cylinders for storing gaseous fuel and fuel supply pipes provided separately corresponding to the fuel cylinders, and between the fuel supply systems. A communication pipe that communicates therewith, and a shutoff valve provided in the middle of the communication pipe, wherein the fuel is passed through the plurality of fuel supply systems while opening and closing the shutoff valve based on a drive signal generated at an appropriate timing. In a gas fuel supply device for an on-board internal combustion engine that supplies gas fuel in a cylinder to a fuel supply unit of an internal combustion engine mounted on a vehicle, a background noise of the vehicle is monitored, and the monitored background noise is lower than a predetermined level. The gist of the invention is to provide a valve drive prohibiting unit that prohibits the opening / closing drive of the shut-off valve when it is small.
[0011]
The so-called background noise of a vehicle, which is transmitted steadily with the driving and depends on the operation of the driver, is the amount of noise that is transmitted through the cabin of the noise generated by driving the vehicle or operating the internal combustion engine. This is a loud sound, and even if it becomes loud, it does not cause discomfort to the driver. On the other hand, according to the above configuration, the shut-off valve is opened and closed only when such background noise is large, and the operation sound can be mixed with the background noise to make it less noticeable. This makes it possible to appropriately reduce the discomfort and the like caused by the opening / closing operation of the shut-off valve.
[0012]
According to a second aspect of the present invention, in the gaseous fuel supply device for an on-vehicle internal combustion engine according to the first aspect, the valve drive prohibiting means monitors background noise of the vehicle based on a rotation speed of the internal combustion engine. The gist is to judge that the background noise is lower than a predetermined level based on the fact that the monitored rotation speed is lower than a predetermined rotation speed.
[0013]
According to the above configuration, it is determined that the noise generated by the internal combustion engine is small based on the rotation speed of the internal combustion engine being lower than the predetermined rotation speed, and accordingly, the background noise is smaller than a predetermined level. Can be determined.
[0014]
According to a third aspect of the present invention, in the gaseous fuel supply device for an in-vehicle internal combustion engine according to the first aspect, the valve drive prohibiting means monitors background noise of the vehicle based on a running speed of the vehicle. The gist of the present invention is to determine that the background noise is smaller than a predetermined level based on the fact that the monitored traveling speed is lower than a predetermined speed.
[0015]
According to the above configuration, it is determined that the road noise and wind noise generated due to the traveling of the vehicle are increasing based on the fact that the traveling speed of the vehicle is lower than the predetermined speed. It can be determined that it is smaller than the level.
[0016]
According to a fourth aspect of the present invention, in the gaseous fuel supply device for an in-vehicle internal combustion engine according to the first aspect, the valve drive prohibiting unit is configured to control at least one of a rotation speed of the internal combustion engine and a traveling speed of the vehicle. Monitoring the background noise of the vehicle on the basis of at least one of the following: the monitored rotation speed is lower than a predetermined rotation speed; and the traveling speed is lower than a predetermined speed. The gist is to judge that it is smaller than.
[0017]
When both the rotation speed of the internal combustion engine and the traveling speed of the vehicle are high, the rotation speed of the internal combustion engine and the traveling speed of the vehicle change at a relatively high speed even when the vehicle is decelerated thereafter. In other words, at this time, the state in which the background noise is large is continued for a relatively long time. On the other hand, according to the above configuration, it is possible to determine that the background noise at that time is small, or that the state may be continued for a relatively short time although the background noise is large. it can. This makes it possible to prohibit the opening / closing drive of the shut-off valve when the background noise is low, and even though the shut-off valve is driven to open / close after determining that the background noise is high. In addition, it is also possible to preferably suppress the occurrence of a situation in which the background noise is reduced during actual driving. Therefore, the opening / closing drive of the shutoff valve can be executed at a more appropriate timing.
[0018]
According to a fifth aspect of the present invention, in the gaseous fuel supply device for an in-vehicle internal combustion engine according to any one of the first to fourth aspects, the plurality of fuel supply systems are provided for a plurality of cylinder groups of the internal combustion engine. The main point is that the fuel is supplied separately.
[0019]
According to the above configuration, the above-described functions, such as the function of operating the internal combustion engine only with the normal fuel supply system and the function of completely using the fuel stored in the plurality of fuel cylinders, cannot be performed with the opening / closing operation of the shut-off valve. This can be realized while suitably relaxing pleasure and the like.
[0020]
Here, the “cylinder group” includes not only a configuration including a plurality of cylinders but also a configuration including a single cylinder.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a gaseous fuel supply device for a vehicle-mounted internal combustion engine according to the present invention will be described.
[0022]
The gaseous fuel supply device according to the present embodiment is assumed to be a device that supplies fuel to a vehicle-mounted internal combustion engine that uses compressed natural gas (CNG) as fuel. Also, as the internal combustion engine to which the gaseous fuel supply device is applied, a V-type internal combustion engine divided into two banks is assumed. Further, in the present embodiment, a plurality of cylinders formed in one bank and a plurality of cylinders provided in the other bank correspond to cylinder groups, respectively.
[0023]
First, a schematic configuration of the gaseous fuel supply device according to the present embodiment will be described with reference to FIG.
As shown in FIG. 1, delivery pipes 6 a and 6 b formed in the same shape are separately arranged in each of the banks 4 a and 4 b of the internal combustion engine 4 mounted on the vehicle 1. Each of the delivery pipes 6a and 6b is provided with a fuel injection valve 10 for injecting CNG into an intake port (not shown) of each cylinder (not shown) corresponding to each cylinder (not shown) of the internal combustion engine 4. Further, CNG is separately supplied to the delivery pipes 6a and 6b through a first fuel supply system 2a and a second fuel supply system 2b, which will be described later. In the device of the present embodiment, the intake port corresponds to a fuel supply unit of the internal combustion engine 4.
[0024]
Further, the device of the present embodiment includes two fuel cylinders 8a and 8b. The first fuel cylinder 8a is formed to have a larger capacity than the second fuel cylinder 8b due to restrictions on the arrangement space in the vehicle 1, and the like.
[0025]
The first fuel cylinder 8a supplies CNG to the first delivery pipe 6a of the left bank 4a via the first high-pressure pipe 12a and the first low-pressure pipe 14a. The first fuel supply system 2a includes the first fuel cylinder 8a, the first high-pressure pipe 12a, the first low-pressure pipe 14a, and the like.
[0026]
In addition, the first fuel supply system 2a is provided with various control valves described below. That is, the first main valve 16a is provided between the first fuel cylinder 8a and the first high-pressure pipe 12a. A first regulator shutoff valve 18a and a first regulator 20a are provided between the first high-pressure pipe 12a and the first low-pressure pipe 14a. Further, a first delivery cutoff valve 22a is provided between the first low-pressure pipe 14a and the first delivery pipe 6a.
[0027]
On the other hand, the second fuel cylinder 8b supplies CNG to the second delivery pipe 6b of the right bank 4b via the second high-pressure pipe 12b and the second low-pressure pipe 14b. The second fuel supply system 2b includes a second fuel cylinder 8b, a second high-pressure pipe 12b, a second low-pressure pipe 14b, and the like. Also in the second fuel supply system 2b, the second main valve 16b, the second regulator shutoff valve 18b, the second regulator 20b, the second delivery shutoff are provided in the same manner as the first fuel supply system 2a. Various control valves such as the valve 22b are provided. In the present embodiment, the high-pressure pipes 12a and 12b and the low-pressure pipes 14a and 14b constitute a fuel supply pipe.
[0028]
In the device of the present embodiment, the first high-pressure pipe 12a and the second high-pressure pipe 12b are connected by the communication pipe 24. Further, a shutoff valve 26 is provided in the communication pipe 24. Then, through the opening and closing drive of the shutoff valve 26, the communication and the cutoff between the first high-pressure pipe 12a and the second high-pressure pipe 12b through the communication pipe 24 are switched at an appropriate timing.
[0029]
Further, a fuel filling pipe 28 having a check valve 28a is connected to each of the fuel cylinders 8a and 8b via each of the main valves 16a and 16b. By introducing CNG from the filling port 28b of the fuel filling pipe 28, CNG can be injected into each of the fuel cylinders 8a and 8b. Each of the base valves 16a and 16b is provided with a check valve (not shown) at a portion connected to the fuel filling pipe 28. The check valve allows CNG to flow from the fuel filling pipe 28 into the fuel cylinders 8a and 8b, while preventing CNG from leaking from the fuel cylinders 8a and 8b to the fuel filling pipe 28 side. Has become.
[0030]
Further, the device of the present embodiment includes various sensors for detecting the properties of CNG and the operating state of the internal combustion engine 4. For example, the high-pressure pipes 12a and 12b are provided with pressure sensors 34a and 34b for detecting CNG pressures P1 and P2 in the pipes 12a and 12b, respectively. Each of the delivery pipes 6a, 6b has a pressure sensor 36a, 36b for detecting the pressure of CNG in the pipe 6a, 6b, and a temperature sensor 38a, 38b for detecting the temperature of the CNG. Is provided. In addition, the internal combustion engine 4 has a rotation speed sensor 40 for detecting the rotation speed (engine rotation speed) NE of its output shaft (not shown), and the vehicle 1 has a vehicle speed for detecting its running speed SPD. Each of the sensors 42 is provided.
[0031]
On the other hand, the device of the present embodiment includes an electronic control device 30 including, for example, a microcomputer, and the electronic control device 30 receives detection signals of the above-described sensors. Then, the electronic control unit 30 performs various calculations based on the signals, and outputs a drive signal based on the calculation results, so that each of the main valves 16a and 16b, each of the regulator shutoff valves 18a and 18b, and each of the delivery shutoffs. The opening and closing control of the valves 22a and 22b and the shutoff valve 26 is executed. Further, the electronic control unit 30 adjusts each of the regulators 20a and 20b based on the calculation result to adjust the pressure of CNG supplied to each of the delivery pipes 6a and 6b to a state corresponding to the operation state of the internal combustion engine 4. are doing.
[0032]
Further, the electronic control unit 30 executes control (fuel injection control) for adjusting the fuel injection amount of each fuel injection valve 10 through drive control of each fuel injection valve 10 based on the calculation result. This fuel injection control is basically performed as follows.
[0033]
That is, first, a basic value of a target fuel injection amount (valve opening time) is calculated based on the engine operating state. Then, a value obtained by adding a correction to this basic value in accordance with the temperature and pressure of CNG in the delivery pipes 6a and 6b is calculated as the target fuel injection amount. Then, each fuel injection valve 10 is driven to open for a time corresponding to the target fuel injection amount. As described above, in the fuel injection control according to the present embodiment, the drive of each fuel injection valve 10 is controlled in accordance with the engine operating state and the properties of CNG in the delivery pipes 6a and 6b, and the fuel injection amount is controlled. Is metered.
[0034]
By the way, in the internal combustion engine using gaseous fuel, such as the internal combustion engine 4 according to the present embodiment, the pressure and temperature of the fuel in each delivery pipe are more biased than the internal combustion engine using liquid fuel. Tends to occur. Such a bias contributes to a difference in the fuel injection amount of each fuel injection valve 10 described above.
[0035]
In order to solve such inconvenience, a plurality of pressure sensors and temperature sensors are provided for each of the delivery pipes 6a and 6b, and the temperature distribution and pressure distribution of CNG in the pipes 6a and 6b are detected, and the distribution is determined according to the distribution. It is also conceivable to adjust the fuel injection amount of each fuel injection valve 10 individually. However, such a configuration is not preferable because it complicates the control structure and increases the cost.
[0036]
Therefore, in the apparatus of the present embodiment, the pressure sensor 36a and the temperature sensor 38a for detecting the properties of CNG in the first delivery pipe 6a are connected to the base end side of the pipe 6a (arrow A in FIG. 1). (Direction side). Further, as for the pressure sensor 36b and the temperature sensor 38b for detecting the properties of CNG in the second delivery pipe 6b, the pressure sensor 36b and the temperature sensor 38b are connected to the tip side of the pipe 6b (the direction opposite to the direction of arrow A in FIG. Is provided at the site.
[0037]
Then, the pressure distribution and the temperature distribution in each of the delivery pipes 6a, 6b are estimated based on the detection signals of the pressure sensors 36a, 36b and the temperature sensors 38a, 38b, respectively. This estimation is based on the assumption that the pressure distribution and the temperature distribution of CNG in each of the delivery pipes 6a and 6b are substantially the same, and the pressure and temperature of the CNG are changed from the proximal end to the distal end of each of the delivery pipes 6a and 6b. It is performed on the premise that it changes equally toward the side end.
[0038]
Thereafter, the temperature and pressure of CNG supplied to each fuel injection valve 10 are individually calculated based on each of the estimated distributions, and further, based on the calculated each temperature and each pressure, the target and the target are calculated. The amount of fuel injection to be performed is calculated for each fuel injection valve 10. Thus, with a configuration in which one pressure sensor and one temperature sensor are provided for each of the delivery pipes 6a and 6b, the fuel injection amount of each fuel injection valve 10 varies in accordance with the temperature and pressure of the supplied CNG. Correction is made separately for each, so that the measurement is accurately performed.
[0039]
Here, various noises such as road noise and wind noise accompanying the traveling of the vehicle 1 and noise associated with the operation of the internal combustion engine 4 are transmitted through the cabin of the vehicle 1. In addition, in the cabin, sounds of audio equipment mounted on the vehicle 1 and sounds of an air conditioner are also generated. The noise that enters the driver's ear in the cabin is called "background noise". After this background noise, particularly the noise associated with the running of the vehicle 1 and the noise associated with the operation of the internal combustion engine 4 are sounds that are constantly generated along with the operation of the vehicle 1, and are caused by the driver's operation. This sound increases with an increase in the traveling speed SPD of the engine and an increase in the engine rotational speed NE. For this reason, even if those noises increase, the driver does not feel uncomfortable.
[0040]
In view of such circumstances, in the device of the present embodiment, in order to alleviate the discomfort caused by the opening / closing operation of the shut-off valve 26, the shut-off is performed when the running speed SPD of the vehicle 1 is low or the engine speed NE is low. The opening and closing drive of the valve 26 is prohibited. That is, by performing the opening / closing drive of the shut-off valve 26 only when the background noise is large, the operation sound is mixed into the background noise so as to be inconspicuous.
[0041]
Hereinafter, the processing procedure of the processing for opening and closing the shutoff valve 26 will be described with reference to the flowchart shown in FIG.
Note that the series of processes shown in the flowchart of FIG. 2 conceptually shows the processing procedure, and is actually executed by the electronic control unit 30 as an interrupt process at predetermined time intervals.
[0042]
As shown in FIG. 2, in this process, first, it is determined whether or not the valve opening flag is operated to “ON” (step S10). The valve opening flag is turned “ON” when it is determined that the shutoff valve 26 needs to be opened through a separate process, and the process of opening and closing the shutoff valve 26 is performed by this process. Is performed (step S60). The timing at which this valve opening flag is turned on includes, for example, the following timing.
-When the internal combustion engine 4 is started.
When the pressure difference between the pressure P1 of CNG in the first high-pressure pipe 12a and the pressure P2 of CNG in the second high-pressure pipe 12b is larger than a predetermined value B.
Execution conditions for failure diagnosis of each fuel supply system 2a, 2b are satisfied.
[0043]
When it is determined that such a valve opening flag is operated to be turned "OFF" (step S10: NO), this processing is temporarily terminated without executing the following processing.
[0044]
On the other hand, when it is determined that the valve opening flag has been operated "ON" (step S10: YES), it is determined whether both of the following (condition a) and (condition b) are satisfied. (Step S20).
(Condition a) The traveling speed SPD of the vehicle 1 is equal to or higher than a predetermined speed α.
(Condition b) The engine speed NE is equal to or higher than a predetermined speed β.
[0045]
Here, it is determined whether or not at least one of the traveling speed SPD of the vehicle 1 and the engine speed NE is kept high even if the vehicle 1 is decelerated by the driver thereafter. Is done. More specifically, when a series of processes (steps S30 to S50), which will be described later, in which the shut-off valve 26 is driven to open and then the shut-off valve 26 is driven to close, the following process is performed. Then, it is determined whether or not the situation where the background noise is large is surely continued.
[0046]
If it is determined that either one of the above (condition a) and (condition b) is not satisfied (step S20: NO), it is determined that both (condition a) and (condition b) are satisfied. This process (step S20) is repeatedly executed until the operation is performed. That is, at this time, assuming that the background noise of the vehicle 1 is small, or that the background noise is not sufficient even though the background noise is large, the valve opening drive of the shut-off valve 26 is prohibited. As described above, in the present embodiment, the process of step S20 functions as a valve drive prohibiting unit that prohibits the open / close drive of the shutoff valve 26.
[0047]
Thereafter, when both the (condition a) and the (condition b) are satisfied (step S20: YES), the background noise is loud at this time, and the state is maintained for a sufficiently long time. Then, the shut-off valve 26 is driven to open (step S30).
[0048]
Thereafter, it is determined whether or not a condition for driving the shutoff valve 26 to close (valve closing condition) is satisfied (step S40). The valve closing conditions include, for example, the following conditions.
-A predetermined time has elapsed since the shut-off valve 26 was opened.
The pressure difference between the pressure P1 of CNG in the first high-pressure pipe 12a and the pressure P2 of CNG in the second high-pressure pipe 12b has become less than a predetermined value C.
[0049]
If it is determined that the valve closing condition is not yet satisfied (step S40: NO), this process (step S40) is repeatedly performed until the condition is satisfied. After that, when the valve closing condition is satisfied (step S40: YES), the shutoff valve 26 is driven to close (step S50). Then, in conjunction with this, after the above-mentioned valve opening flag is turned off (step S60), the present process is temporarily ended.
[0050]
Hereinafter, how the process of opening and closing the shutoff valve 26 is performed will be described with reference to a timing chart shown in FIG.
FIG. 3 shows an example of a processing mode of the above processing. 3A shows the transition of the operation state of the valve opening flag, FIG. 3B shows the transition of the engine speed NE, FIG. 3C shows the transition of the running speed SPD of the vehicle 1, and FIG. Indicates the transition of the operating state of the shut-off valve 26.
[0051]
Further, in the example shown in FIG. 3, at the timing t1, the following conditions are satisfied.
The engine speed NE shown in FIG. 3B is lower than the predetermined speed β.
The traveling speed SPD of the vehicle 1 shown in FIG. 3 (c) is lower than the predetermined speed α.
-The shut-off valve 26 shown in FIG. 3D is closed.
[0052]
In the present example, at such a timing t1, the valve opening flag is turned on as shown in FIG.
However, at this time, as shown in FIG. 3B, the engine rotational speed NE is lower than the predetermined rotational speed β, and as shown in FIG. It is less than α. For this reason, at this time, since the background noise of the vehicle 1 is small, when the shut-off valve 26 is driven to open, the operation noise may be noticeably increased and may cause discomfort to the driver. As shown, the opening drive of the shutoff valve 26 is prohibited.
[0053]
After that, the prohibition of the opening of the shut-off valve 26 is prohibited, as shown in FIG. 3C, when the traveling speed SPD of the vehicle 1 becomes equal to or higher than the predetermined speed α (timing t2), and further, as shown in FIG. ), The operation is continued over a period (timing t1 to t3) until the engine rotation speed NE becomes equal to or higher than the predetermined rotation speed β.
[0054]
Then, at the timing t3, the background noise of the vehicle 1 is under a large situation, and the situation surely continues over a period until the shut-off valve 26 is driven to be closed (timing t3 to t4 in this example). As shown in FIG. 3D, the shutoff valve 26 is driven to open.
[0055]
Then, at timing t4, when the valve closing condition is satisfied, the shutoff valve 26 is driven to close as shown in FIG. 3D.
As described above, according to the present embodiment, the following effects can be obtained.
[0056]
(1) When the background noise of the vehicle 1 is low, the opening / closing drive of the shut-off valve 26 is prohibited. As a result, the opening / closing drive of the shut-off valve 26 can be executed only when the background noise is loud, and the operation sound can be mixed with the background noise to make it inconspicuous. Therefore, the discomfort of the driver due to the opening / closing operation of the shutoff valve 26 can be appropriately mitigated.
[0057]
(2) The opening / closing drive of the shut-off valve 26 is prohibited when the engine speed NE is lower than the predetermined speed β. This makes it possible to determine that the noise generated by the internal combustion engine 4 is small, and thereby to determine that the background noise is lower than a predetermined level at which the above-mentioned discomfort can be suitably alleviated. Become like
[0058]
(3) When the traveling speed SPD of the vehicle 1 is lower than the predetermined speed α, the opening and closing drive of the shutoff valve 26 is prohibited. Accordingly, it is determined that road noise, wind noise, and the like accompanying the traveling of the vehicle 1 are reduced, and accordingly, the background noise is lower than a predetermined level at which the discomfort can be appropriately alleviated. Can be determined.
[0059]
(4) Only when the traveling speed SPD of the vehicle 1 is equal to or higher than the predetermined speed α and the engine rotation speed NE is equal to or higher than the predetermined rotation speed β, the opening of the shut-off valve 26 is permitted. Accordingly, only when the background noise of the vehicle 1 is large and the situation is to be maintained for a period until the shutoff valve 26 is driven to close thereafter, the cutoff is performed. The valve 26 is driven to open. Therefore, even if the shut-off valve 26 is driven to open and close after determining that the background noise is increasing, the occurrence of a situation in which the background noise is reduced during actual driving is appropriately suppressed. As a result, the opening / closing drive of the shutoff valve 26 can be executed at a more appropriate timing.
[0060]
(5) The function of operating the internal combustion engine 4 only by the normal fuel supply system 2a or 2b and the function of using up the CNG stored in each of the fuel cylinders 8a and 8b to the end, and the opening and closing of the shutoff valve 26 It is possible to realize while appropriately reducing the discomfort of the driver accompanying the operation.
[0061]
The above embodiment may be implemented with the following modifications.
In the above embodiment, the opening drive of the shutoff valve 26 is permitted when the traveling speed SPD of the vehicle 1 is equal to or higher than the predetermined speed α and the engine rotation speed NE is equal to or higher than the predetermined rotation speed β. . The present invention is not limited to this, and if the valve closing drive of the shut-off valve 26 is reliably performed when the background noise is large, it is only when the traveling speed SPD of the vehicle 1 is equal to or higher than the predetermined speed or when the engine rotation speed NE is set to the predetermined value. The opening drive of the shutoff valve 26 may be permitted only when the speed is equal to or higher than the speed.
[0062]
The process shown in FIG. 4 may be executed instead of the process (FIG. 2) for opening and closing the shutoff valve 26 described in the above embodiment. In the process shown in FIG. 4, the processes shown in steps S10 to S30 and steps S40 to S60 are the same processes as the processes shown in the previous FIG. 2 (steps S10 to S30 and steps S40 to S60). Therefore, the detailed description is omitted.
[0063]
In this process, after the shut-off valve 26 is driven to open (step S30), it is determined whether or not the engine speed NE is equal to or higher than a predetermined speed γ (step S31). Here, when the engine rotational speed NE is equal to or higher than the predetermined rotational speed γ, it is determined that the background noise of the vehicle 1 is in a state large enough to allow the operation sound of the shut-off valve 26 to be appropriately mixed. .
[0064]
If it is determined that the engine rotation speed NE is equal to or higher than the predetermined rotation speed γ (step S31: YES), it is determined whether the valve closing condition is satisfied (step S40). If it is determined that the valve closing condition has not been satisfied (step S40: NO), the engine speed NE is maintained at or above the predetermined speed γ, and the valve closing condition is satisfied. These processes (steps S31 and S40) are repeatedly executed until the process is started. After that, when the engine rotational speed NE is equal to or higher than the predetermined rotational speed γ and the above-described valve closing condition is satisfied (step S31: YES and step S40: YES), the shutoff valve 26 is driven to close (step S31). S50).
[0065]
On the other hand, even when the engine speed NE falls below the predetermined speed γ before the valve closing condition is satisfied (step S31: NO), the shutoff valve 26 is also driven to close (step S32). However, in this case, if the valve closing drive of the shut-off valve 26 is further delayed, the background noise becomes excessively small and the driver may feel uncomfortable with the valve closing drive. 26 is forcibly closed. Then, the process returns to the process of step S20.
[0066]
According to such processing, it is possible to suitably suppress the shut-off valve 26 from being driven to close in a situation where the background noise of the vehicle 1 is excessively small.
Here, in the above processing, the engine speed NE is equal to or higher than the predetermined speed γ, which means that the background noise of the vehicle 1 is in a situation that is large enough to allow the operation sound of the shutoff valve 26 to be properly mixed. Judgment was made solely for the following reasons. In order to determine that the background noise is loud and the state of the loud background noise continues for a relatively long time as in the process of step S20 described in FIG. It is effective to determine that both the engine speed NE and the engine speed NE are increasing. However, here, it is only necessary to be able to determine only that the background noise at that time is increasing. Normally, the background noise of the vehicle 1 is higher when the engine speed NE is higher than when the traveling speed SPD of the vehicle 1 is higher. In view of such circumstances, in the above-described processing, only when the engine speed NE is equal to or higher than the predetermined speed γ, the background noise of the vehicle 1 is large enough to allow the operation sound of the shut-off valve 26 to be properly mixed. I try to judge that it is below.
[0067]
Note that this determination is made only when the traveling speed SPD of the vehicle 1 is equal to or higher than the predetermined speed, or when the traveling speed SPD of the vehicle 1 is equal to or higher than the predetermined speed and the engine rotation speed NE is equal to or higher than the predetermined rotation speed. It is of course possible to do so.
[0068]
In the above-described embodiment, the conditions for closing the shut-off valve 26 include a condition that the engine speed NE is equal to or higher than a predetermined speed and a condition that the traveling speed SPD of the vehicle 1 is equal to or higher than a predetermined speed. It may be newly added.
[0069]
In the above embodiment, the fact that the background noise of the vehicle 1 is smaller than the predetermined level is determined based on the engine speed NE and the traveling speed SPD of the vehicle 1. Alternatively or additionally, it may be determined that the background noise of the vehicle 1 is smaller than a predetermined level based on the operation state of the audio equipment mounted on the vehicle 1. It is also possible to provide a noise sensor in the cabin of the vehicle 1 and determine that the background noise is smaller than a predetermined level based on a detection signal of the sensor.
[0070]
In the above embodiment, the present invention is applied to the gaseous fuel supply device having the communication pipe 24 connecting the high-pressure pipes 12a and 12b and the shutoff valve 26 for opening and closing the communication pipe 24. However, the present invention is not limited to this. A gas fuel supply device having a communication pipe that connects the fuel cylinders 8a and 8b and a shutoff valve that opens and closes the communication pipe, or a communication pipe that connects the low-pressure pipes 14a and 14b and the same. The present invention is also applicable to a gaseous fuel supply device having a shutoff valve for opening and closing a pipe.
[0071]
In the above-described embodiment, the present invention is applied to a case where a plurality of cylinders provided in the left bank 4a and a plurality of cylinders provided in the right bank 4b are respectively set as cylinder groups, and fuel supply is performed for each cylinder group. The present invention is applied to an apparatus provided with the systems 2a and 2b. The present invention is not limited to this, and the present invention is also applicable to an apparatus in which a plurality of cylinder groups are set for each of the banks 4a and 4b, and a fuel supply system is provided for each of the cylinder groups. In short, a plurality of fuel supply systems for individually supplying CNG to a plurality of cylinder groups of the internal combustion engine, a communication pipe communicating between the fuel supply systems, and a shutoff valve for opening and closing the communication pipe are provided. The present invention can be appropriately applied to a device.
[0072]
In the above embodiment, the V-type internal combustion engine 4 having the two banks 4a and 4b is used as the internal combustion engine to which the gaseous fuel supply device according to the present invention is applied. A horizontally opposed internal combustion engine having two banks can also be used. The present invention can also be applied to an in-line type internal combustion engine by dividing into a plurality of cylinder groups and providing a fuel supply system for each cylinder group.
[0073]
The device to which the gaseous fuel supply device according to the present invention can be applied is not limited to a device having a plurality of fuel supply systems for individually supplying CNG to a plurality of cylinder groups. In short, the present invention can be appropriately applied to any gas fuel supply device that includes a plurality of fuel supply systems, a communication pipe communicating between the fuel supply systems, and a shutoff valve that opens and closes the communication pipe. it can.
[0074]
In the above embodiment, the present invention is applied to the internal combustion engine that injects CNG to the intake port. However, the present invention is not limited to this. The present invention can also be applied to an internal combustion engine of the type in which CNG is directly injected into a cylinder.
[0075]
In the above embodiment, the gaseous fuel supply device used for the internal combustion engine using CNG as a fuel has been described, but the present invention is not limited to this. In short, any device that supplies gaseous fuel to an internal combustion engine can employ the gaseous fuel supply device according to the present invention.
[0076]
The embodiments of the present invention have been described above, but it should be noted that the embodiments of the present invention include the following embodiments.
(1) Two delivery pipes formed in substantially the same shape or a substantially symmetric shape, and a plurality of fuel injection valves provided corresponding to each fuel supply portion of the internal combustion engine and injecting gaseous fuel in the delivery pipe. The basic value of the target fuel injection amount is obtained based on the current engine operating state, and the basic value is corrected based on the fuel property to calculate the target fuel injection amount. In the gaseous fuel supply device that supplies gaseous fuel to each fuel supply portion of the on-vehicle internal combustion engine through drive control of the plurality of fuel injection valves based on the target fuel injection amount, a sensor for detecting the property of the fuel, A vehicle characterized by being provided on one of the delivery pipes on the upstream side in the extending direction and on the other delivery pipe on the downstream side in the extending direction. Gas fuel supply apparatus for an internal combustion engine.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a gaseous fuel supply device for a vehicle-mounted internal combustion engine according to the present invention.
FIG. 2 is an exemplary flowchart showing a processing procedure for opening and closing the shutoff valve according to the embodiment;
FIG. 3 is a timing chart showing an example of a processing procedure of the processing.
FIG. 4 is a flowchart showing a processing procedure of a modification of the processing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2a ... 1st fuel supply system, 2b ... 2nd fuel supply system, 4 ... Internal combustion engine, 4a ... Left bank, 4b ... Right bank, 6a ... 1st delivery pipe, 6b ... 2nd delivery pipe, 8a ... first fuel cylinder, 8b ... second fuel cylinder, 10 ... fuel injection valve, 12a ... first high pressure pipe, 12b ... second high pressure pipe, 14a ... first low pressure pipe, 14b ... second low pressure pipe, 16a ... 1-way valve, 16b: 2nd-way valve, 18a: 1st regulator shut-off valve, 18b: 2nd regulator shut-off valve, 20a: 1st regulator, 20b: 2nd regulator, 22a: 1st delivery shut-off valve, 22b ... 2 Delivery cut-off valve, 24 communication pipe, 26 cut-off valve, 28 fuel filling pipe, 28a check valve, 28b filling port, 30 electronic control unit, 34a, 34b, 36a, 36b pressure sensor, 38a , 3 b ... Temperature sensor, 40 ... rotational speed sensor, 42 ... vehicle speed sensor.

Claims (5)

A plurality of fuel cylinders for storing gaseous fuel, a plurality of fuel supply systems each including a fuel supply pipe provided separately for each of the fuel cylinders, a communication pipe communicating between the fuel supply systems, and a middle of the communication pipe; A gas fuel in the fuel cylinder is mounted on the vehicle through the plurality of fuel supply systems while opening and closing the shut-off valve based on a drive signal issued at an appropriate timing. In a gaseous fuel supply device for a vehicle-mounted internal combustion engine that supplies a fuel supply unit of the internal combustion engine,
A gas fuel supply device for a vehicle-mounted internal combustion engine, comprising: valve drive inhibiting means for monitoring the background noise of the vehicle, and prohibiting the opening / closing drive of the shut-off valve when the monitored background noise is smaller than a predetermined level. . The valve drive prohibiting means monitors the background noise of the vehicle based on the rotation speed of the internal combustion engine. When the monitored rotation speed is lower than a predetermined rotation speed, the background noise becomes lower than a predetermined level. The gaseous fuel supply device for an on-vehicle internal combustion engine according to claim 1, wherein it is determined that the gaseous fuel is also smaller. The valve drive prohibiting means monitors background noise of the vehicle based on the traveling speed of the vehicle, and the background noise is lower than a predetermined level when the monitored traveling speed is lower than a predetermined speed. The gaseous fuel supply device for an in-vehicle internal combustion engine according to claim 1, wherein the determination is made. The valve drive prohibiting means monitors background noise of the vehicle based on at least one of a rotation speed of the internal combustion engine and a traveling speed of the vehicle, and the monitored rotation speed is lower than a predetermined rotation speed. The gaseous fuel supply device for an in-vehicle internal combustion engine according to claim 1, wherein it is determined that the background noise is lower than a predetermined level based on at least one of: a running speed lower than a predetermined speed. The gaseous fuel supply device for a vehicle-mounted internal combustion engine according to any one of claims 1 to 4, wherein the plurality of fuel supply systems respectively supply fuel to a plurality of cylinder groups of the internal combustion engine.

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