GAS FUEL FILLING AND SUPPLYING SYSTEM

A gas fuel filling and supplying system includes: a tank; a filling pipe having a filling port; a supplying pipe; a branch pipe that branches from a connection part between the filling pipe and the supplying pipe and is connected to the tank; a normally closed solenoid value provided in the branch pipe; and a control part that controls opening and closing of the solenoid valve, wherein the control part controls the solenoid valve to be in an open state while a gas engine is driven, controls the solenoid valve to be in a closed state while the gas engine is stopped, and controls the solenoid valve to be in an open state during filling of the tank with gas fuel from the filling port.

TECHNICAL FIELD

The present disclosure relates to a gas fuel filling and supplying system, and more particularly, to technology suitable for a fuel filling and supplying system of a gas engine.

BACKGROUND OF THE INVENTION

Conventionally, a vehicle equipped with a gas engine using compressed natural gas (hereinafter referred to as CNG) as a fuel has been put into practical use. A fuel filling and supplying system of this type of gas engine is disclosed in Patent Document 1, for example.

PRIOR ART

Patent Literature

BRIEF DESCRIPTION OF THE INVENTION

Problem to be Solved by the Invention

The above-mentioned fuel filling and supplying system includes a fuel tank that stores CNG. A filling pipe through which CNG flows from a filling port into which a nozzle is inserted when fuel is filled and a supplying pipe through which CNG flows at the time of supplying CNG to the engine are connected to the fuel tank. The downstream end of the filling pipe and the upstream end of the supplying pipe are joined to each other, and are connected to the fuel tank as a single pipe (hereinafter, a branch pipe).

The branch pipe may be provided with a solenoid valve serving as a main stop valve which is turned on when the engine is running and turned off when the engine is stopped or when fuel is filled. Since CNG pushes open and passes through a valve element of the solenoid valve while the fuel is being filled, vibration occurs in the solenoid valve, and such vibration affects noise, durability of the pipe, and the like.

The present disclosure focuses on these points, and its object is to effectively prevent the occurrence of vibration in a solenoid valve when fuel is filled.

Means for Solving the Problem

According to an embodiment of the present disclosure, there is provided a technology including: a tank that stores gas fuel; a filling pipe provided with a filling port for the gas fuel at an upstream end; a supplying pipe having an upstream end connected to a downstream end of the filling pipe and a downstream end connected to an injector facing an intake passage of a gas engine; a branch pipe that branches from a connection part between the filling pipe and the supplying pipe and is connected to the tank; a normally closed solenoid valve provided in the branch pipe; and a control part that controls opening and closing of the solenoid valve, wherein the control part controls the solenoid valve to be in an open state while the gas engine is driven, controls the solenoid valve to be in a closed state while the gas engine is stopped, and controls the solenoid valve to be in an open state during filling of the tank with the gas fuel from the filling port.

It is preferable that the technology further includes a detection means that detects insertion of the fuel nozzle into the filling port and removal of the fuel nozzle from the filling port, wherein the control part may control the solenoid valve to be in an open state when the detection means detects the insertion of the fuel nozzle, and control the solenoid valve to be in a closed state when the detection means detects the removal of the fuel nozzle.

Preferably, the technology further includes an engine switch that transmits a signal indicating running or stoppage of the gas engine to the control part; and a battery, wherein the solenoid valve may include an electromagnetic coil, and the control part may control the solenoid valve to be in an open state by supplying a current from the battery to the electromagnetic coil when the detection means detects the insertion of the fuel nozzle while receiving a signal indicating stoppage of the gas engine from the engine switch.

Further, it is preferable that the control part may determine whether the detection means has detected the removal of the fuel nozzle while controlling the electromagnetic coil to be energized and the solenoid valve to be in the open state due to the detection means detecting the insertion of the fuel nozzle.

Effect of the Invention

According to the technology of the present disclosure, it is possible to effectively prevent the occurrence of vibration in the solenoid valve when fuel is filled.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a gas fuel filling and supplying system according to the present embodiment will be described with reference to the attached drawings. The same components are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

FIG.1is a schematic overall configuration diagram showing an engine10and a gas fuel filling and supplying system30according to the present embodiment.

As shown inFIG.1, the engine10, serving as a drive power source, is mounted on a vehicle1. The engine10is a gas engine using gas as a fuel, and is configured as a CNG engine using CNG as the fuel in the present embodiment.

The engine10mainly includes a cylinder head11and an engine body including a cylinder block12. The cylinder block12is provided with a cylinder C that reciprocally accommodates a piston P. A crankshaft15is connected to the piston P via a connecting rod13, a crank arm14, and the like, and reciprocating motion of the piston P is converted into rotational motion and transmitted to the crankshaft15. For the sake of illustration,FIG.1shows only one cylinder among a plurality of cylinders of the engine10, and the other cylinders are not shown. The engine10may be either multi-cylinder or single-cylinder.

The cylinder head11is provided with an intake port11A and an exhaust port11B. The intake port11A is a part that introduces intake air into the cylinder C. The exhaust port11B is a part through which exhaust is led out from the cylinder C. The cylinder head11is provided with an intake valve16and an exhaust valve17. The intake valve16and the exhaust valve17are opened and closed by a valve mechanism (not shown). Further, the cylinder head11is provided with a spark plug18. The spark plug18is a component that ignites CNG supplied to a combustion chamber of the cylinder C.

An intake manifold20is provided at a side portion of the cylinder head11on the intake side. The intake manifold20communicates with the intake port11A. An intake passage21is connected to the intake manifold20. The intake passage21is for introducing intake air. In the intake passage21, an air cleaner22, an injector37, and the like are provided in this order from upstream of intake. The air cleaner22is a device that removes foreign substances. The injector37is a device that injects CNG. In the figure, a reference numeral25denotes an exhaust manifold that collects exhaust gas, and a reference numeral26denotes an exhaust passage for leading exhaust out from the exhaust manifold25.

The gas fuel filling and supplying system30includes a fuel tank31, a filling pipe32, a supplying pipe33, and a branch pipe34. The fuel tank31is a tank that stores CNG. The filling pipe32is a pipe for filling CNG. The supplying pipe33is a pipe for supplying CNG.

A filling port35is provided at an upstream end of the filling pipe32. The filling port35is an approximately cylindrical part into which a fuel nozzle70is inserted when the CNG is filled. A downstream end of the filling pipe32joins the upstream end of the supplying pipe33. The downstream end of the supplying pipe33is connected to a fuel gallery36, and CNG is distributed and supplied to the injector37of each cylinder via the fuel gallery36.

The branch pipe34branches from a connecting site between the filling pipe32and the supplying pipe33, and is connected to the fuel tank31. The branch pipe34is provided with a manual valve50and a solenoid valve40serving as a main stop valve. The solenoid valve40is a normally closed solenoid valve, and opens when a current flows through an electromagnetic coil (not shown) in response to a command from the controller100. The solenoid valve40is opened (ON) while the engine10is driven, and causes CNG to flow from the fuel tank31to the supplying pipe33. Further, the solenoid valve40is closed (OFF) while the engine10is stopped, and prevents leakage of CNG from the fuel tank31. A detailed configuration of the solenoid valve40will be described later.

The filling pipe32is provided with a check valve51. The check valve51prevents the CNG from flowing back from the fuel tank31to the filling port35. The supplying pipe33is provided with a regulator52. The regulator52is a device for decompressing or regulating the pressure of high-pressure CNG supplied from the fuel tank31.

An engine switch91and a nozzle sensor92are electrically connected to the controller100. The engine switch91transmits, to the controller100, an ON/OFF signal indicating whether the engine10is running or stopped. The nozzle sensor92(detection means of the present disclosure) detects insertion of the fuel nozzle70into the filling port35and removal of the fuel nozzle70from the filling port35. Here, the nozzle sensor92is provided adjacent to the filling port35, and detects insertion or removal of the fuel nozzle70by contacting the fuel nozzle70. The nozzle sensor92is not limited to a contact type sensor, and may be a non-contact type sensor.

FIG.2is a schematic cross-sectional view showing the solenoid valve40according to the present embodiment.

As shown inFIG.2, the solenoid valve40includes a valve part40A and a solenoid part40B. The valve part40A includes a housing41interposed in the branch pipe34(seeFIG.1). The housing41is provided with a first flow passage42A, a second flow passage42B, and a chamber42C. The first flow passage42A communicates with the filling port3side. The second flow passage42B communicates with the fuel tank31side. The chamber42C communicates with the first flow passage42A and the second flow passage42B. In the chamber42C, a valve element43is accommodated such that it can move in an axial direction.

The second flow passage42B is connected to the chamber42C from a direction approximately orthogonal to the axial direction of the valve element43. The first flow passage42A is connected to the chamber42C from the axial direction of the valve element43. A valve seat44is provided between the first flow passage42A and the chamber42C. The valve seat44is a part on which the valve element43is seated. The chamber42C is provided with a spring45. The spring45is a part that constantly urges the valve element43toward the valve seat44to seat the valve element43on the valve seat44.

The solenoid part40B includes a case46. The case46is a bottomed cylindrical part attached to the housing41. An electromagnetic coil47is accommodated in the case46, and a fixed iron core (plug nut)48and a movable iron core (plunger)49are provided in the electromagnetic coil47. The fixed iron core48is fixed in the electromagnetic coil47so as not to move in the axial direction. The movable iron core49is provided such that it can move in the axial direction and coaxially with the fixed iron core48. A rod43A of the valve element43is fixed to the movable iron core49such that they can move integrally. The material of the fixed iron core48and the movable iron core49is not limited to iron, and a wide range of magnetic materials other than iron can be used.

The solenoid valve40supplies a current to the electromagnetic coil47when the engine10is driven. When the electromagnetic coil47is energized, the fixed iron core48is magnetized by magnetic force, and the movable iron core49is attracted to the fixed iron core48side by the magnetic force, whereby the valve element43is separated from the valve seat44against a biasing force of the spring45. When the valve element43is separated from the valve seat44, the solenoid valve40enters an open state in which the CNG flows from the second flow passage42B toward the first flow passage42A in the direction of an arrow A.

On the other hand, the solenoid valve40interrupts the supply of current to the electromagnetic coil47when the engine10is stopped. When the electromagnetic coil47is de-energized, the valve element43is pressed against the valve seat44by the biasing force of the spring45, whereby the solenoid valve40enters a closed state in which the flow of the CNG in the direction of the arrow A from the second flow passage42B toward the first flow passage42A is interrupted.

Here, even when the CNG is filled, the CNG in the direction of an arrow B filled from the first flow passage42A side pushes open the valve element43and flows to the second flow passage42B when the solenoid valve40is in the closed state. At this time, since the CNG pushes open the valve element43against the biasing force of the spring45, the CNG may vibrate the valve element43in the axial direction (vertical direction in the figure) depending on velocity, pressure, specific gravity, and the like of flowing fluid. The solenoid valve40of the present embodiment has a function of suppressing the occurrence of such vibration at the time of filling the CNG. Hereinafter, details of this function will be described.

FIG.3is a schematic diagram showing the controller100according to the present embodiment and related peripheral configurations.

The controller100is a device, such as a computer, that performs computation, and includes a drive control circuit110and a microcomputer (hereinafter referred to as a microcomputer)120, for example.

The drive control circuit110is an IC, and controls energization of the electromagnetic coil47of the solenoid valve40, for example. The microcomputer120includes a CPU, a ROM, a RAM, and the like. An ON/OFF signal indicating whether the engine10is running or stopped is input to the microcomputer120from the engine switch91. A detection signal indicating insertion of the fuel nozzle70into the filling port35and a detection signal indicating removal of the fuel nozzle70from the filling port35are input to the microcomputer120from the nozzle sensor92.

When the engine switch91is turned on, the drive control circuit110supplies a current to the electromagnetic coil47from an in-vehicle battery (not shown) to energize the electromagnetic coil47. When the electromagnetic coil47is energized, the solenoid valve40enters an open state in which the CNG flows.

On the other hand, when the engine switch91is turned OFF, the drive control circuit110cuts off the current to the electromagnetic coil47, thereby de-energizing the electromagnetic coil47. When the electromagnetic coil47is de-energized, the solenoid valve40enters a closed state in which outflow of the CNG from the fuel tank31is interrupted.

When the nozzle sensor92detects the insertion of the fuel nozzle70while the engine switch91is in the OFF state, the drive control circuit110supplies a current to the electromagnetic coil47from an in-vehicle battery (not shown), thereby controlling the solenoid valve40to be in the open state. As a result, when the CNG passes through the solenoid valve40, the CNG smoothly flows through the solenoid valve40in the open state without pushing open the valve element43, thereby reliably preventing the occurrence of vibration at the time of filling. When the nozzle sensor92detects the removal of the fuel nozzle70that accompanies the completion of filling the CNG, the drive control circuit110switches the solenoid valve40from the open state to the closed state by de-energizing the electromagnetic coil47.

Next, a control process according to the present embodiment will be described with reference toFIG.4.

In step S100, it is determined whether the engine switch91is turned on. If the engine switch91is turned on (Yes in S100), this control process proceeds to processing of step S200. On the other hand, if the engine switch91is not turned on (NO in S100), that is, if the engine switch91is turned off, this control process proceeds to a determination process of step S110.

In step S200, the electromagnetic coil47is energized and the solenoid valve40enters an open state. Once the solenoid valve40is opened, this control process returns to the determination of step S100.

In step S110, it is determined whether the fuel nozzle70has been inserted into the filling port35. If the fuel nozzle70is inserted into the filling port35(Yes in S110), this control process proceeds to processing of step S120. On the other hand, if the fuel nozzle70is not inserted into the filling port35(No in S110), this control process proceeds to processing of step S180, in which the solenoid valve40is maintained to be in the closed state, and returns to the determination of step S100.

In step S120, the electromagnetic coil47is energized to open the solenoid valve40. Next, in step S130, it is determined whether the fuel nozzle70has been pulled out from the filling port35. If the fuel nozzle70is not pulled out from the filling port35(No in S130), this control process returns to processing of step S120. On the other hand, if the fuel nozzle70is pulled out from the filling port35(Yes in S130), this control process proceeds to processing of step S140, in which the solenoid valve40enters a closed state by de-energizing the electromagnetic coil47, and then proceeds to return.

According to the present embodiment described in detail above, the present disclosure includes the solenoid valve40, serving as the main stop valve, which is provided in the branch pipe34which branches from the connecting site between the filling pipe32and the supplying pipe33and is connected to the fuel tank31. The present embodiment is configured to control the solenoid valve40to enter the open state when filling the fuel tank31with the CNG from the filling port35through the filling pipe32and the branch pipe34.

Accordingly, when the CNG is filled, the CNG smoothly flows through the solenoid valve40without pushing open the valve element43of the solenoid valve40, and vibration of the valve element43in the axial direction can be effectively prevented. Further, since the vibration of the valve element43is suppressed, it is possible to effectively prevent noise and a reduction of durability of the branch pipe34caused by the vibration.

When the CNG is filled, the solenoid valve40is opened at the same time that the fuel nozzle70is inserted into the filling port35and closed at the same time that the fuel nozzle70is pulled out from the filling port35. This makes it possible to more effectively prevent leakage of the CNG from the fuel tank31as compared with the case where opening and closing of the solenoid valve40is controlled in accordance with opening and closing of a door covering the filling port35.

The present disclosure is not limited to the above-described embodiments, and can be appropriately modified and implemented without departing from the gist of the present disclosure.

For example, the solenoid valve40has been described as being applied to the filling and supplying system of CNG in the above embodiment, but the solenoid valve40may be applied to a filling and suppling system of other fluids (including liquids and gases). Further, the application of the present disclosure is not limited to the gas engine mounted on the vehicle1, and can be widely applied to a gas engine of an industrial machine such as a generator.

DESCRIPTION OF SYMBOLS