JPH09242614A - Device for detecting gaseous fuel leaking - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the loss generated by leakage of fuel by judging and informing leakage of gaseous fuel in the case where the ratio between a present pressure changing rate per unit time of gaseous fuel detected by a pressure sensor and a referential pressure changing rate set beforehand is a setting value or more at the time of running of a vehicle. SOLUTION: It is judged whether a leakage detecting condition is set up or not by rotational speed and an engine load by whether a prescribed operating condition is continued for a prescribed time in an engine (106), in the case of 'YES', a map value corresponding to the condition is set as a read-in referential pressure changing rate (a) (108), a present pressure value detected by a pressure sensor is read in (110), and a present pressure changing rate (b) in the prescribed time of gaseous fuel is found out (112). The referential pressure changing rate (a) and the present pressure changing rate (b) are compared with each other, it is judged whether the ratio is a primary prescribed value or more (114). In this case, leakage from a fuel piping system is judged, a detecting lump is lightened (116). When the ratio is a secondary setting value or more (118), an emergency fuel shut-out valve is closingly operated (120).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas fuel leak detection device, and more particularly, it can detect a small amount of leak of gas fuel from a fuel piping system and can prevent loss due to gas fuel leak. The present invention relates to a gas fuel leak detection device that can contribute to energy saving.

[0002]

2. Description of the Related Art Vehicles include a natural gas vehicle (NGV) which is a gas fuel vehicle equipped with an engine that uses CNG (compressed natural gas) which is a gas fuel.

In such a vehicle, a gaseous fuel container for storing gaseous fuel to be supplied to the engine is provided, and an overflow prevention valve is provided in this gaseous fuel container, and one end side of the fuel supply pipe is provided in this overflow prevention valve. And the other end of this fuel supply pipe is connected to the mixer of the engine.
There is one in which an emergency cutoff valve, a pressure sensor, a fuel cutoff valve, and a pressure reducing valve are provided in the fuel supply pipe.

The gaseous fuel in the gaseous fuel container is taken out by the fuel supply pipe, adjusted to a predetermined pressure and flow rate by the pressure reducing valve, mixed with air by the mixer and supplied to the engine.

The gas fuel container is provided with an overflow prevention valve. The overflow prevention valve closes and shuts off the outflow of the gaseous fuel from the gaseous fuel container when the gaseous fuel more than the consumption amount by the engine flows due to the damage of the fuel piping system due to an accident or the like.

An example of such a gas fuel leak detection device is disclosed in Japanese Patent Application Laid-Open No. 61-272455. The publication disclosed in this publication is provided with a flow velocity sensor for detecting the flow velocity of fuel in a fuel supply passage of a gas engine, and a fuel leak or clogging of the fuel supply passage is detected by a detection signal of the flow velocity sensor to display or sound. The control means for informing by is provided.

[0007]

The overflow prevention valve provided in the gaseous fuel container does not close unless a large amount of gaseous fuel flows. For this reason, the overflow prevention valve is closed when, for example, the fuel piping system is damaged due to an accident or the like.

However, the fact that the gaseous fuel is likely to leak is that the gaseous fuel gradually leaks little by little due to loosening of the joint portion of the fuel piping system due to vehicle vibration or the like.

Therefore, in the current gas-fueled vehicles, although the rapid leakage of the gas fuel due to the damage of the fuel piping system can be prevented by the overflow prevention valve of the gas fuel container, the gas fuel that is most likely to occur originally is There is an inconvenience that it is impossible to detect a leak gradually and prevent the leak.

Therefore, in the gas fuel vehicle, since it is not possible to detect and prevent the leak of the gas fuel gradually, there is a disadvantage that the gas fuel is lost and energy saving cannot be achieved.

[0011]

In order to eliminate the above-mentioned inconvenience, the present invention provides a gaseous fuel container for storing gaseous fuel supplied to an engine mounted on a vehicle, and the gaseous fuel container is provided in the gaseous fuel container. An overflow prevention valve is provided, one end side of the fuel supply pipe is connected to the overflow prevention valve, and the other end side of the fuel supply pipe is connected to the mixer of the engine. A shutoff valve, a pressure sensor, a fuel shutoff valve, and a pressure reducing valve are provided so as to intervene, and the current pressure change amount per unit time of the gaseous fuel detected by the pressure sensor when the vehicle is traveling and the preset per unit time When the ratio to the basic pressure change amount is equal to or more than a set value, it is characterized by providing a control means for determining that the gaseous fuel is leaking and controlling the informing means to perform an informing operation.

Further, according to the present invention, a gaseous fuel container for storing gaseous fuel supplied to an engine mounted on a vehicle is provided, an overflow preventing valve is provided in the gaseous fuel container, and fuel is supplied to the overflow preventing valve. One end of the pipe is connected and the other end of the fuel supply pipe is connected to the mixer of the engine, and an emergency cutoff valve, a pressure sensor, a fuel cutoff valve, and a pressure reducing valve are provided in the fuel supply pipe. The ratio of the current pressure change amount per unit time of the gaseous fuel detected by the pressure sensor when the vehicle is traveling and the preset basic pressure change amount per unit time is not less than the first set value. In this case, it is determined that the gas fuel is leaking, and the notification means is controlled to perform an alarm operation, and the current pressure change amount per unit time of the gas fuel detected by the pressure sensor when the vehicle is traveling and the preset unit time. Hit When the ratio to the basic pressure change amount is equal to or larger than the second set value which is larger than the first set value, it is determined that the gas fuel leaks and the emergency shutoff valve and the fuel shutoff valve are closed. A control means for controlling is provided.

Further, according to the present invention, a gaseous fuel container for storing gaseous fuel supplied to an engine mounted on a vehicle is provided, an overflow prevention valve is provided in the gaseous fuel container, and fuel is supplied to the overflow prevention valve. One end of the pipe is connected and the other end of the fuel supply pipe is connected to the mixer of the engine, and an emergency cutoff valve, a pressure sensor, a fuel cutoff valve, and a pressure reducing valve are provided in the fuel supply pipe. The pressure value of the gaseous fuel detected by the pressure sensor when the ignition switch of the engine is turned on when the engine is started and the pressure of the gaseous fuel detected by the pressure sensor when the engine is cranked. When the difference from the value is equal to or more than the set value and the difference between the cooling water temperature of the engine and the intake air temperature is less than a predetermined value, it is determined that the gas fuel is leaked and the notifying means is notified. Characterized in that a Gosuru control means.

Further, according to the present invention, a gaseous fuel container for storing gaseous fuel supplied to an engine mounted on a vehicle is provided, an overflow preventing valve is provided in the gaseous fuel container, and fuel is supplied to the overflow preventing valve. One end of the pipe is connected and the other end of the fuel supply pipe is connected to the mixer of the engine, and an emergency cutoff valve, a pressure sensor, a fuel cutoff valve, and a pressure reducing valve are provided in the fuel supply pipe. The pressure value of the gaseous fuel detected by the pressure sensor when the ignition switch of the engine is turned on when the engine is started and the pressure of the gaseous fuel detected by the pressure sensor when the engine is cranked. If the difference from the value is equal to or more than the set value and the opening mechanism of the fuel lid for filling the gaseous fuel into the gaseous fuel container is not operated before the engine is started, it is determined that the gaseous fuel leaks. And characterized in that a control means for controlling so as to notification operation informing means.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the gaseous fuel leak detection apparatus of the present invention, the control means controls the current pressure change amount per unit time of the gaseous fuel detected by the pressure sensor when the vehicle is running and the preset per unit time. When the ratio to the basic pressure change amount is equal to or greater than the set value, it is determined that the gas fuel is leaking, and the notification means is controlled to perform an alarm operation to detect the gradual leakage of the gas fuel while the vehicle is running. It is possible to make the driver sense.

Further, the gas fuel detection device of the present invention comprises:
When the ratio of the current pressure change amount per unit time of the gaseous fuel detected by the pressure sensor during traveling of the vehicle and the preset basic pressure change amount per unit time by the control means is equal to or more than the first set value. While controlling the alarm means to determine that the fuel gas is leaking, the current pressure change amount per unit time of the gas fuel detected by the pressure sensor when the vehicle is traveling and the preset basic time per unit time are controlled. The second value whose ratio with the pressure change amount is larger than the first set value
When it is equal to or more than the set value, it is possible to detect the gradual leakage of the gaseous fuel when the vehicle is running by determining that the gaseous fuel is leaking and controlling the closing valve to close the emergency shutoff valve and the fuel shutoff valve. The driver can detect the leakage, and the fuel supply pipe can be closed to prevent the leakage when the leakage of the gaseous fuel is large enough to prevent the overflow prevention valve from closing.

Further, in the gaseous fuel leak detection apparatus of the present invention, the control means causes the difference between the pressure value of the gaseous fuel when the ignition switch is turned on at the time of starting the engine and the pressure value of the gaseous fuel when the cranking is performed. Is greater than or equal to a set value and the difference between the cooling water temperature and the intake air temperature is less than a predetermined value, it is determined that the gas fuel is leaking, and the notification means is controlled to perform an alarm operation. While avoiding erroneous detection when the gas fuel is filled and the pressure value changes, it is possible to detect a gradual leakage of the gas fuel when the engine is started and to make the driver sense it.

Further, in the gas fuel leak detection device of the present invention, the control means causes the difference between the pressure value of the gas fuel when the ignition switch is turned on at the time of starting the engine and the pressure value of the gas fuel when the cranking is performed. Is equal to or more than the set value and the opening mechanism of the fuel lid for filling the gaseous fuel into the gaseous fuel container is in the non-operating state before the engine is started, it is determined that the gaseous fuel is leaked and the informing means is informed. With this control, it is possible to detect a gradual leak of the gaseous fuel at the time of starting the engine while avoiding an erroneous detection when the gaseous fuel is filled and the pressure value changes before starting the engine with a simple configuration. It can be detected by the driver.

[0019]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment of the present invention. In FIG. 2, reference numeral 2 is an engine mounted on a vehicle (not shown) and supplied with gaseous fuel such as CNG (compressed natural gas). The engine 2 has an air cleaner 4, a mixer 6, and an intake manifold 8 in the intake system, a throttle valve 12 in the intake passage 10, an exhaust manifold 14 in the exhaust system, and an exhaust passage 16.

The gaseous fuel supplied to the engine 2 is
It is stored in the gaseous fuel container 18. The gas fuel container 18 is
An overflow prevention valve 20 is provided. The overflow prevention valve 20 closes when gas fuel more than the amount consumed by the engine 2 flows due to damage to the fuel piping system due to an accident or the like, and shuts off the outflow of gas fuel from the gas fuel container 8. is there. In addition, in FIG. 2, two gaseous fuel containers 18 are provided in parallel.

A fuel supply pipe 22 is provided in the overflow prevention valve 20.
One end side of is connected and provided. The other end of the fuel supply pipe 22 is connected to the mixer 6 of the engine 2. In the fuel supply pipe 22, the emergency shutoff valve 24, the pressure sensor 26, and the fuel shutoff valve 28 are sequentially arranged from the gaseous fuel container 18 side.
And a high pressure pressure reducing valve 30 and a low pressure pressure reducing valve 32 which are pressure reducing valves.

The emergency shutoff valve 24 comprises a solenoid valve,
To secure the safety of the fuel supply system, the gas fuel container 18
Will be installed at the location closest to. The pressure sensor 26 is
It is installed on the downstream side of the emergency shutoff valve 24 and detects the pressure of the gaseous fuel.

The fuel cutoff valve 28 is an electromagnetic valve,
When the engine 2 is stopped, the closing operation is performed to prevent the gaseous fuel from flowing to the mixer 6. The high-pressure pressure reducing valve 30 and the low-pressure pressure reducing valve 32 adjust the gas fuel to have an appropriate pressure and flow rate and supply the gas fuel to the mixer 6.

Further, one end side of a fuel filling pipe 34 is connected to the fuel supply pipe 22 adjacent to the gaseous fuel container 18. A filling coupler 36 is provided on the other end side of the fuel filling pipe 34. A filling instrument (not shown) of a filling device is connected to the filling coupler 36 when filling the gaseous fuel container 18 with the gaseous fuel. In the fuel filling pipe 34, a filling valve 38 and a check valve 40 are sequentially provided from the side of the filling coupler 36.

The emergency shutoff valve 24, the pressure sensor 26 and the fuel shutoff valve 28 are connected to the control means 44 of the gas fuel leak detection device 42. The control means 44 includes an engine speed sensor 46 for detecting the engine speed Ne.
An intake negative pressure sensor 48 for detecting the intake negative pressure Pb of the intake passage 10, a throttle sensor 50 for detecting the throttle opening θ of the throttle valve 12, and an intake air amount for detecting the intake air amount Ga of the intake passage 10. A sensor 52 and a vehicle speed sensor 54 that detects a vehicle speed V of a vehicle (not shown) are connected and provided.

Further, the leak detecting device 42 is provided with a leak detecting lamp 56 as a notifying means which is informed when the leak of the gaseous fuel is detected. The leak detection lamp 56 is connected to the control means 44.

The control means 44 sets the ratio between the current pressure change amount per unit time of the gaseous fuel detected by the pressure sensor 26 during traveling of the vehicle and the preset basic pressure change amount per unit time at a set value or more. In some cases, it is determined that the gas fuel is leaking, and the leak detection lamp 56, which is a notification unit, is controlled to be turned on as a notification operation.

The control means 44 of the first embodiment is a ratio of the current pressure change amount per unit time of the gaseous fuel detected by the pressure sensor 26 when the vehicle is running to the preset basic pressure change amount per unit time. Is greater than or equal to the first set value, it is determined that the gas fuel has leaked, and the leak detection lamp 56, which is a notification unit, is controlled to be turned on as a notification operation.
A second setting in which the ratio of the current pressure change amount per unit time of the gaseous fuel detected by the pressure sensor 26 during traveling of the vehicle and the preset basic pressure change amount per unit time is larger than the first set value. If it is equal to or more than the value, it is judged that the gas fuel is leaking, and the emergency shutoff valve 24 and the fuel shutoff valve 28 are controlled to be closed.

That is, in the control means 44, as shown in FIG. 1, a map of the pressure change amount of the gaseous fuel due to being consumed by the engine 2 at a predetermined time t under a predetermined condition is prepared in advance for various conditions. And remember it. The control means 44
When the operating state of the engine 2 has passed a predetermined time t under the predetermined condition while the vehicle is running, a map value corresponding to the condition is read to change the basic pressure per unit time t of the gaseous fuel, that is, the basic pressure change at the predetermined time t. Let the amount a. Also,
The control unit 44 obtains the current pressure change amount b per unit time t of the gaseous fuel detected by the pressure sensor 26, that is, the current pressure change amount b at the predetermined time t when the operating state of the engine 2 has passed the predetermined time t under the predetermined condition. .

The control means 44 compares the basic pressure change amount a read from the map with the obtained present pressure change amount b, and when the ratio r is equal to or more than the first set value r1, the fuel piping system It is determined that the gaseous fuel has leaked from the vehicle, and the leak detection lamp 56 is turned on. Further, the control means 44 compares the basic pressure change amount a read from the map with the obtained present pressure change amount b, and the ratio thereof is larger than the first set value r1 in the second set value r2 ( When r1 <r2) or more, it is determined that the gas fuel has leaked, and the emergency shutoff valve 24 and the fuel shutoff valve 28 are closed.

Next, the operation of the first embodiment will be described.

When the control means 44 starts control (step 102) in the gas fuel leak detection device 42, as shown in FIG. 1, a signal indicating the operating state of the engine 2 when the vehicle is traveling at the vehicle speed V. As a result, the engine speed Ne and the intake negative pressure Pb (or the throttle opening θ or the intake air amount Ga) which is the load are read (step 104).

It is judged whether or not a predetermined time t has elapsed under a predetermined condition of the operating condition of the engine 2 (step 106). For example, when the engine speed Ne is equal to or lower than a predetermined value Ne ′ (Ne ≦ ± Ne ′) and the intake negative pressure Pb as a load is equal to or lower than a predetermined value Pb ′ (Pb ≦ ± Pb ′), the time ta is a predetermined time t. It is determined whether or not has passed (ta ≧ t).
That is, it is determined whether the leak detection execution condition is satisfied or not depending on whether the engine 2 has been in the predetermined operating state for the predetermined time t depending on the engine speed and the engine load.

If this determination (step 106) is NO, the process returns to reading (step 104).

If this judgment (step 106) is YES, the map value corresponding to the condition is read and set as the basic pressure change amount a (step 108). Further, the control means 44 reads the present pressure value detected by the pressure sensor 26 (step 110) and obtains the present pressure change amount b per unit time t of the gaseous fuel, that is, at the predetermined time t (step 112).

The control means 44 compares the basic pressure change amount a read from the map with the calculated present pressure change amount b, and the ratio r is the first set value r1 or more (for example, a ≧ 1.
2b) is determined (step 114).

In this determination (step 114), if the ratio is less than the first set value r1 and NO, the process returns to the reading (step 104).

In this judgment (step 114), if the ratio is equal to or more than the first set value r1 and YES, it is judged that the gaseous fuel leaks from the fuel piping system and the leak detection lamp 5
6 is turned on (step 116).

Next, the control means 44 controls the basic pressure change amount a read from the map and the calculated present pressure change amount b.
Are compared with each other, and it is determined whether or not the ratio r is equal to or larger than the second set value r2 which is larger than the first set value r1 (for example, a ≧ 1.4b) (step 118).

In this judgment (step 118), if the ratio r is equal to or more than the second set value r2 and YES, it is judged that the gas fuel leaks and the emergency cutoff valve 24 and the fuel cutoff valve 2 are judged.
8 is closed (step 120) to end (step 122).

In this determination (step 118), if the ratio r is less than the second set value r2 and NO, the process ends (step 122).

As described above, in the leak detecting device 42, the current pressure change amount b per unit time (predetermined time t) of the gaseous fuel detected by the pressure sensor 26 during traveling of the vehicle by the control means 44 and the preset unit. When the ratio r to the basic pressure change amount a per hour (predetermined time t) is equal to or larger than the first set value r1, it is determined that the gas fuel is leaking and the leak detection lamp 56
The present pressure change amount b of the gaseous fuel per unit time (predetermined time t) detected by the pressure sensor 26 during traveling of the vehicle and the basic pressure per preset unit time (predetermined time t) When the ratio r to the change amount a is equal to or larger than the second set value r2 which is larger than the first set value r1, it is determined that the gas fuel is leaking, and the emergency cutoff valve 24 and the fuel cutoff valve 28 are closed. Control to do so.

As a result, the leak detection device 42 can detect the gradual leak of the gaseous fuel when the vehicle is running, and the driver can sense the leak by the leak detection lamp 56. Further, the leak detection device 42 can prevent the leak by closing the fuel supply pipe 22 when the leak of the gaseous fuel is large enough to prevent the overflow prevention valve 20 from closing.

Therefore, this gas fuel leak detection device 4
No. 2 can detect a small amount of leakage of the gaseous fuel from the fuel piping system when the vehicle is traveling, can prevent loss due to the leakage of the gaseous fuel, and can contribute to energy saving.

3 and 4 show a second embodiment of the present invention. In the second embodiment, the parts having the same functions as those in the first embodiment are designated by the same reference numerals and will be briefly described. That is, in FIG. 4, 2 is an engine, 4 is an air cleaner 4, 6 is a mixer, 8 is an intake manifold, 10
Is an intake passage, 12 is a throttle valve, 14 is an exhaust manifold, and 16 is an exhaust passage.

The gas fuel container 18 for storing the gas fuel supplied to the engine 2 is provided with an overflow prevention valve 20, and one end of a fuel supply pipe 22 is connected to the overflow prevention valve 20 to supply the fuel. The other end of the pipe 22 is connected to the mixer 6. The fuel supply pipe 22 is provided with an emergency shutoff valve 24, a pressure sensor 26, a fuel shutoff valve 28, a high pressure pressure reducing valve 30, and a low pressure pressure reducing valve 32, which are sequentially provided from the gas fuel container 18 side.

The emergency shutoff valve 24 is a solenoid valve.
The pressure sensor 26 detects the pressure of the gaseous fuel. The fuel cutoff valve 28 is an electromagnetic valve. High pressure reducing valve 30
The low pressure reducing valve 32 adjusts the gaseous fuel to an appropriate pressure and flow rate.

Further, one end of a fuel filling pipe 34 is connected to the fuel supply pipe 22 adjacent to the gaseous fuel container 18, and a filling coupler 36 is provided at the other end of the fuel filling pipe 34. In the fuel filling pipe 34, a filling valve 38 and a check valve 40 are sequentially provided from the filling coupler 36 side.

The emergency shutoff valve 24, the pressure sensor 26 and the fuel shutoff valve 28 are connected to the control means 44 of the gaseous fuel leak detection device 42. The control means 44 includes an ignition switch 58 for the engine 2, a starter switch 60 for driving a starter motor (not shown) to crank the engine 2, and a water temperature sensor 62 for detecting a cooling water temperature Tw of the engine 2. An intake air temperature sensor 64 that detects an intake air temperature Ta of the intake passage 10 and a vehicle speed sensor 54 that detects a vehicle speed V of a vehicle (not shown) are connected to each other.

Further, the leak detecting device 42 is provided with a leak detecting lamp 56 as a notifying means which is informed when the leak of the gaseous fuel is detected. The leak detection lamp 56 is connected to the control means 44.

The control means 44 of the second embodiment controls the pressure value X of the gaseous fuel when the ignition switch 58 is turned on at the time of starting the engine 2 and the pressure value of the gaseous fuel when the cranking is performed by turning on the starter switch 60. The difference (X'-X) from X'is greater than or equal to the set value Y, and the cooling water temperature T
The difference (| Tw-Ta |) between w and the intake air temperature Ta is a predetermined value T.
If it is less than the above, it is determined that the gas fuel has leaked, and the leak detection lamp 56, which is the notification means, is controlled to light as a notification operation.

Next, the operation of the second embodiment will be described.

In the gas fuel leak detection device 42, when the control is started by the control means 44 as shown in FIG. 3 (step 202), the ignition switch 58 is turned on.
The pressure value X detected by the pressure sensor 26 at the time of (step 204) is read (step 206).

Next, the emergency shutoff valve 24 and the fuel shutoff valve 28 are cranked by turning on the starter switch 60.
Is opened (step 208), and the pressure value X ′ detected by the pressure sensor 26 at the time of cranking is read (step 210).

The control means 44 uses the ignition switch 5
The difference (X′−X) between the pressure value X of the gaseous fuel when turning ON 8 and the pressure value X ′ of the gaseous fuel when cranking by turning on the starter switch 60 is compared, and the difference is the set value Y. It is determined whether or not (X′−X ≧ Y) (step 212).

In this determination (step 212), if the difference is less than the set value Y (X'-X <Y) and the answer is NO, the process jumps to the end (step 220).

In this determination (step 212), if the difference is equal to or greater than the set value Y and YES (X'-X≥Y), the difference between the cooling water temperature Tw and the intake air temperature Ta (| Tw-T
a |) are compared, and the difference is a predetermined value T or more (| Tw-Ta
It is determined whether or not | ≧ T) (step 214).

In this determination (step 214), if the difference is equal to or greater than the predetermined value T (| Tw-Ta | ≧ T), YES, it is determined that the gaseous fuel has been filled and normal processing is performed (step 216). ) To end (Step 2
20).

In this judgment (step 214), if the difference is less than the predetermined value T (| Tw-Ta | <T) and NO, it is judged that the gas fuel is leaking from the fuel piping system. The leak detection lamp 56 is turned on (step 21
8) and the end is reached (step 220).

Thus, the leak detection device 4 of the second embodiment is
2 is an ignition switch 58 when the engine 2 is started.
The difference between the pressure value X of the gaseous fuel when the engine is turned on and the pressure value X ′ of the gaseous fuel when the engine 2 is cranked by turning on the starter switch 60 is greater than or equal to the set value Y, and the cooling water temperature Tw and When the difference from the intake air temperature Ta is less than the predetermined value T, it is determined that the gas fuel is leaking, and the leak detection lamp 56 is turned on.

As a result, the leak detection device 42 avoids erroneous detection when the gaseous fuel is filled and the pressure value changes at the time of starting the engine 2, while gradually leaking the gaseous fuel at the time of starting the engine 2. It can be detected and can be detected by the driver.

Therefore, this gaseous fuel leak detection device 4
No. 2 can detect a slight leak of the gaseous fuel from the fuel piping system at the time of starting the engine, can prevent a loss due to the leakage of the gaseous fuel, and can contribute to energy saving.

That is, when the gaseous fuel is gradually leaking from the fuel piping system when the engine 2 is started, the pressure sensor 26
The pressure value detected by is lower than the pressure value of the gaseous fuel container 18. The emergency shutoff valve 24 and the fuel shutoff valve 28 are
Since the starter switch 60 is opened after cranking by turning on, the pressure value after cranking becomes larger than the pressure value when turning on the ignition switch 58 when the gaseous fuel is leaking.

Therefore, when this value is larger than a certain value, it can be judged that the gaseous fuel is leaking.

However, when the engine 2 is started after being filled with the gaseous fuel, the pressure value after cranking becomes large. Therefore, in such a case, it is necessary to determine that it is normal.

When the gas fuel container 18 is filled with the gaseous fuel, the vehicle is normally run to the stand, so the engine 2 is warmed up.

Therefore, when the engine 2 is started, if the difference (| Tw-Ta |) between the cooling water temperature Tw and the intake air temperature Ta is more than a certain value, it can be determined that the gaseous fuel has been filled.

As a result, the leak detection device 4 of the second embodiment is
2, the difference (X'-X) between the pressure value X when the ignition switch 58 is turned on at the time of starting the engine 2 and the pressure value X'when cranking is the set value Y or more, as described above. In addition, the difference between the cooling water temperature Tw and the intake air temperature Ta (| T
When w−Ta |) is less than the predetermined value T, it is determined that the gas fuel has leaked, and the leak detection lamp 56 is turned on.

Therefore, the leak detection device 42 avoids erroneous detection when the gas fuel is filled and the pressure value changes before the engine 2 is started, while gradually reducing the amount of the gas fuel when the engine 2 is started. It is possible to detect each leak, can be detected by the driver, it is possible to detect a little leak of the gaseous fuel from the fuel piping system, it is possible to prevent the loss due to the leak of the gaseous fuel, It can contribute to energy saving.

5 and 6 show a third embodiment of the present invention. In the third embodiment, the parts having the same functions as those in the first embodiment are designated by the same reference numerals and will be briefly described. That is, in FIG. 6, 2 is an engine, 4 is an air cleaner 4, 6 is a mixer, 8 is an intake manifold,
Is an intake passage, 12 is a throttle valve, 14 is an exhaust manifold, and 16 is an exhaust passage.

The gas fuel container 18 for storing the gas fuel supplied to the engine 2 is provided with an overflow prevention valve 20, and one end of a fuel supply pipe 22 is connected to the overflow prevention valve 20 to supply the fuel. The other end of the pipe 22 is connected to the mixer 6. The fuel supply pipe 22 is provided with an emergency shutoff valve 24, a pressure sensor 26, a fuel shutoff valve 28, a high pressure pressure reducing valve 30, and a low pressure pressure reducing valve 32, which are sequentially provided from the gas fuel container 18 side.

The emergency shutoff valve 24 is a solenoid valve.
The pressure sensor 26 detects the pressure of the gaseous fuel. The fuel cutoff valve 28 is an electromagnetic valve. High pressure reducing valve 30
The low pressure reducing valve 32 adjusts the gaseous fuel to an appropriate pressure and flow rate.

Further, one end of a fuel filling pipe 34 is connected to the fuel supply pipe 22 adjacent to the gaseous fuel container 18, and a filling coupler 36 is provided at the other end of the fuel filling pipe 34. In the fuel filling pipe 34, a filling valve 38 and a check valve 40 are sequentially provided from the filling coupler 36 side.

The filling coupler 36 is covered with an openable fuel lid (fuel lid) 66 for filling gaseous fuel. The fuel lid 66 is held in a closed state by a lid lock mechanism 68. The lid lock mechanism 68 is released by the operation of the opening mechanism (fuel opener) 70, and allows the fuel lid 66 to be opened. The opening mechanism 70 is provided with an opening switch 72 which is turned on at the time of opening operation.

The emergency shutoff valve 24, the pressure sensor 26 and the fuel shutoff valve 28 are connected to the control means 44 of the gas fuel leak detection device 42. The control means 44 includes an ignition switch 58 for the engine 2, a starter switch 60 for driving a starter motor (not shown) to crank the engine 2, and an opening mechanism 70 for opening the fuel lid 66 for filling the gaseous fuel. An opening switch 72 that is turned on at the time of opening operation and a vehicle speed sensor 54 that detects a vehicle speed V of a vehicle (not shown) are connected and provided.

Further, the leak detecting device 42 is provided with a leak detecting lamp 56 as a notifying means for notifying when the leak of the gaseous fuel is detected. The leak detection lamp 56 is connected to the control means 44.

The control means 44 of the third embodiment uses the pressure value X of the gaseous fuel when the ignition switch 58 is turned on at the time of starting the engine 2 and the pressure value of the gaseous fuel when the cranking is performed by turning on the starter switch 60. The difference (X′−X) from X ′ is equal to or greater than the set value Y, and the opening mechanism 70 of the fuel lid 66 for filling the gaseous fuel into the gaseous fuel container 18 is turned off before the engine 2 is started. When it is in the non-operation state, it is determined that the gas fuel has leaked, and the leak detection lamp 56, which is a notification unit, is controlled to be turned on as a notification operation.

Next, the operation of the third embodiment will be described.

In the gaseous fuel leak detecting device 42, when the control means 44 starts the control (step 302) as shown in FIG. 5, the ignition switch 58 is turned on.
The pressure value X detected by the pressure sensor 26 at the time of (step 304) is read (step 306).

Next, the emergency shutoff valve 24 and the fuel shutoff valve 28 are cranked by turning on the starter switch 60.
Is opened (step 308), and the pressure value X ′ detected by the pressure sensor 26 at the time of cranking is read (step 310).

The control means 44 uses the ignition switch 5
The difference (X′−X) between the pressure value X of the gaseous fuel when turning ON 8 and the pressure value X ′ of the gaseous fuel when cranking by turning on the starter switch 60 is compared, and the difference is the set value Y. It is determined whether or not (X′−X ≧ Y) (step 312).

In this judgment (step 312), if the difference is less than the set value Y (X'-X <Y) and the answer is NO, the process jumps to the end (step 320).

In this determination (step 312), if the difference is equal to or greater than the set value Y and YES (X'-X≥Y), it is determined whether the opening switch 72 was ON before the engine 2 was started. (Step 314).

In this judgment (step 314), before the engine 2 is started, the opening switch 72 is ON and Y
In the case of ES, it is determined that the gas fuel has been filled, the normal processing is performed (step 316), and the process ends (step 320).

In this judgment (step 314), if the open switch 72 is OFF and NO before the engine 2 is started, it is judged that the gaseous fuel has leaked from the leaked fuel piping system, and the leak detection lamp 56 is turned on. Lighting (step 318)
Then, the process ends (step 320).

As described above, the leak detection device 4 of the third embodiment is
2 is an ignition switch 58 when the engine 2 is started.
The difference between the pressure value X of the gaseous fuel when turning ON the switch and the pressure value X ′ of the gaseous fuel when cranking by turning the starter switch 60 ON is a set value Y or more, and before starting the engine 2, When the opening mechanism 70 of the fuel lid 66 for filling the gaseous fuel into the container 18 is in the non-operating state by turning off the opening switch 72, it is judged that the gaseous fuel is leaking, and the leak detection lamp 56 is turned on.

That is, in the third embodiment, the fuel lid 6
When the opening mechanism 70 of No. 6 is operated to open, it is determined to be normal because the pressure value is large due to the filling with the gaseous fuel, and the opening mechanism 70 of the fuel lid 66 is not operated to open. When the pressure value is large despite the fact that the gaseous fuel is not filled, it is judged that there is a leak and the leak detection lamp 56 is turned on.

As a result, the leak detection device 42 of the third embodiment uses a simpler configuration than the second embodiment to detect erroneous detection when the gas fuel is filled and the pressure value changes when the engine 2 is started. While avoiding, a gradual leak of gaseous fuel can be detected when the engine 2 is started and can be detected by the driver.

Therefore, the gas fuel leak detection device 4
No. 2 can detect a slight leak of the gaseous fuel from the fuel piping system at the time of starting the engine, can prevent a loss due to the leakage of the gaseous fuel, and can contribute to energy saving.

[0090]

As described above, the device for detecting leakage of gaseous fuel of the present invention can detect the gradual leakage of gaseous fuel when the vehicle is running, and can easily detect it by the driver.
In addition, it is possible to detect a gradual leak of gaseous fuel while the vehicle is running, which can be easily detected by the driver, and to supply fuel when there is a large amount of gaseous fuel leakage to the extent that the overflow prevention valve does not close. The pipes can be closed to prevent leakage, and furthermore, the gradual leakage of gaseous fuel at engine startup is avoided while avoiding false detection when the gaseous fuel is filled and the pressure value changes before engine startup. Can be detected by the driver and can be easily detected by the driver. Also, while avoiding erroneous detection when the gas fuel is filled and the pressure value changes before the engine is started with a simple configuration, it is possible to start the engine. Sometimes a gradual leak of gaseous fuel can be detected and made visible to the driver.

Therefore, this gas fuel leak detection device can detect small leaks of the gas fuel from the fuel piping system, prevent loss due to the leak of the gas fuel, and contribute to energy saving. obtain.

[Brief description of drawings]

FIG. 1 is a first diagram of a gas fuel leak detection device according to the present invention.
It is a flow chart of control which shows an example.

FIG. 2 is a schematic configuration diagram of a gas fuel leak detection device.

FIG. 3 is a second view of the gas fuel leakage detection device according to the present invention.
It is a flow chart of control which shows an example.

FIG. 4 is a schematic configuration diagram of a gas fuel leak detection device.

FIG. 5 is a third embodiment of the gas fuel leakage detection device according to the present invention.
It is a flow chart of control which shows an example.

FIG. 6 is a schematic configuration diagram of a gas fuel leak detection device.

[Explanation of symbols]

 2 Engine 4 Air Cleaner 6 Mixer 8 Intake Manifold 10 Intake Passage 12 Throttle Valve 14 Exhaust Manifold 16 Exhaust Passage 18 Gas Fuel Container 20 Overflow Prevention Valve 22 Fuel Supply Pipe 24 Emergency Cutoff Valve 26 Pressure Sensor 28 Fuel Cutoff Valve 30 High Pressure Reduction Valve 32 Low pressure reducing valve 34 Fuel filling pipe 36 Filling coupler 38 Filling valve 40 Check valve 42 Leak detecting device 44 Control means 46 Engine speed sensor 48 Intake negative pressure sensor 50 Throttle sensor 52 Intake air amount sensor 52 Vehicle speed sensor 56 Leak detecting lamp

Claims (4)

[Claims] 1. A gas fuel container for storing gas fuel supplied to an engine mounted on a vehicle is provided, and an overflow prevention valve is provided in the gas fuel container, and one end side of a fuel supply pipe is provided in the overflow prevention valve. And the other end of the fuel supply pipe is connected to the mixer of the engine, and the fuel supply pipe is provided with an emergency cutoff valve, a pressure sensor, a fuel cutoff valve, and a pressure reducing valve. When the ratio of the current pressure change amount per unit time of the gaseous fuel detected by the pressure sensor while the vehicle is traveling and the preset basic pressure change amount per unit time is equal to or more than a set value, A gaseous fuel leak detection device, characterized in that a control means is provided for controlling the informing means to perform an informing operation upon determining that there is a leak. 2. A gas fuel container for storing gas fuel supplied to an engine mounted on a vehicle is provided, and an overflow prevention valve is provided in the gas fuel container, and the overflow prevention valve has one end side of a fuel supply pipe. And the other end of the fuel supply pipe is connected to the mixer of the engine, and the fuel supply pipe is provided with an emergency cutoff valve, a pressure sensor, a fuel cutoff valve, and a pressure reducing valve. When the ratio of the current pressure change amount per unit time of the gaseous fuel detected by the pressure sensor during traveling of the vehicle to the preset basic pressure change amount per unit time is equal to or more than the first set value, the gas Controlling the alarm means to perform an alarm operation upon judging that the fuel has leaked, the current pressure change amount per unit time of the gaseous fuel detected by the pressure sensor while the vehicle is traveling, and the preset basic pressure per unit time. Change amount and When the ratio is greater than or equal to the second set value that is greater than the first set value, it is determined that the gas fuel has leaked, and control means for controlling the closing operation of the emergency cutoff valve and the fuel cutoff valve is performed. A leak detector for gaseous fuel, characterized by being provided. 3. A gas fuel container for storing a gas fuel supplied to an engine mounted on a vehicle is provided, and an overflow prevention valve is provided in the gas fuel container, and one end side of a fuel supply pipe is provided in the overflow prevention valve. And the other end of the fuel supply pipe is connected to the mixer of the engine, and the fuel supply pipe is provided with an emergency cutoff valve, a pressure sensor, a fuel cutoff valve, and a pressure reducing valve. A difference between the pressure value of the gaseous fuel detected by the pressure sensor when the ignition switch of the engine is turned on when the engine is started and the pressure value of the gaseous fuel detected by the pressure sensor when the engine is cranked. Is greater than or equal to a set value and the difference between the engine cooling water temperature and the intake air temperature is less than a predetermined value, a control means is provided to control the notification means by determining that the fuel gas is leaking. A leak detection device for gaseous fuel, which is characterized by being punctured. 4. A gas fuel container for storing a gas fuel supplied to an engine mounted on a vehicle is provided, and an overflow prevention valve is provided in the gas fuel container, and the overflow prevention valve has one end side of a fuel supply pipe. And the other end of the fuel supply pipe is connected to the mixer of the engine, and the fuel supply pipe is provided with an emergency cutoff valve, a pressure sensor, a fuel cutoff valve, and a pressure reducing valve. A difference between the pressure value of the gaseous fuel detected by the pressure sensor when the ignition switch of the engine is turned on when the engine is started and the pressure value of the gaseous fuel detected by the pressure sensor when the engine is cranked. Is greater than or equal to the set value and the opening mechanism of the fuel lid for filling the gaseous fuel into the gaseous fuel container is in the non-operating state before the engine is started, it is judged that the gaseous fuel is leaking and the notifying means is notified. A gaseous fuel leak detection device, characterized in that a control means for controlling the intelligent operation is provided.