Gas fuel supply device for engine

Abstract

To avoid, in an engine system comprising an exhaust gas recirculation device, function failure due to infiltration of condensate water into an intake pipe pressure introduction pipe.SOLUTION: A gas fuel supply device for an engine has a fuel cylinder 1, a regulator 2, an intake passage 5 comprising a throttle 3 and a mixer 4, a fuel pipe 8, an engine 10, and an exhaust gas recirculation device 13 that recirculates part of exhaust gas to the intake passage 5 as EGR gas, the gas fuel supply device comprising an intake pressure outlet formed in the intake passage 5, and a mounting part formed around the intake pressure outlet. The regulator 2 has an intake pressure inlet 30 formed on its outer surface. The regulator 2 is fixed to the mounting part by a fixing member in a state where the intake pressure outlet and the intake pressure inlet 30 are in direct and airtight communication.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas fuel supply device that converts gas fuel stored in a liquid or high-pressure gas state into gas at a predetermined pressure and supplies it to an engine, and in particular to a gas fuel supply device for an engine having a regulator with an intake pressure introduction function. [Background technology]

[0002] Conventionally, in gas fuel supply devices that supply gas fuel such as LPG, CNG, or hydrogen gas stored in a liquid or high-pressure gas state to an engine, it is common to use a regulator to reduce the pressure to a predetermined level before supplying it to the engine.

[0003] As a regulator structure, a piston-type regulator that opens and closes a pressure regulating valve using a piston that displaces axially to reduce and adjust the gas pressure to a predetermined level is known, as shown, for example, in Patent Publication No. 2013-041375 (Patent Document 1) and Patent Publication No. 2019-067216 (Patent Document 2).

[0004] In such conventional piston-type regulators, the inside of the main body is divided into a primary pressure chamber (inlet side) and a secondary pressure chamber (discharge side) by a piston, and a pressure adjustment spring that urges the piston toward the secondary pressure chamber is provided within the spring chamber.

[0005] The piston is displaced axially due to the balance between the force of the gas that passes through the pressure regulating valve and moves from the primary pressure chamber to the secondary pressure chamber, pushing the piston toward the primary pressure chamber, and the force of the pressure regulating spring pushing the piston toward the secondary pressure chamber, thereby opening and closing the pressure regulating valve and regulating the pressure.

[0006] Known types of spring chambers include those that are closed, those that communicate with the atmosphere through a through hole, and those that introduce intake pressure to vary the pressure in the spring chamber.

[0007] As an example of introducing intake pressure into a regulator, FIG. 6 shows a gas fuel supply device disclosed as a conventional example in Japanese Patent Application Laid-Open No. 2021-191952 (Patent Document 3) previously filed by the applicant of the present application.

[0008] In this conventional gas fuel supply device, high-pressure gas fuel filled and stored in a fuel cylinder 1a is supplied to an engine 9a via a fuel filter 3a, an injector 4a, a fuel pipe 5a, a mixer 7a disposed in an intake passage 6a, an intake manifold 8a, and the engine 9a while the high-pressure gas fuel is reduced to a predetermined pressure by a regulator 2a. The intake manifold 8a and the regulator 2a are connected by an intake pipe pressure introduction pipe 10a, and the intake pipe pressure is introduced into the regulator 2a to adjust the pressure of the discharged gas fuel.

[0009] However, if the intake manifold 8a and the regulator 2a are directly connected by the intake pipe pressure introduction pipe 10a, moisture such as condensed water generated on the intake passage 6a side will enter the intake pipe pressure introduction pipe 10a from the pressure outlet 11a, causing a problem in that the intake pipe pressure introduction pipe 10a will malfunction.

[0010] In particular, in an engine system having an exhaust gas recirculation (EGR) device that recirculates part of the exhaust gas, such as the conventional example shown in FIG. 6, it is known that the EGR gas cooled by the EGR cooler 12a is likely to fall below the dew point temperature, and therefore condensed water is likely to occur in the intake passage 6a. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-041375 [Patent Document 2] Japanese Patent Application Publication No. 2019-067216 [Patent Document 3] Patent Publication No. 2021-191952 Summary of the Invention [Problem to be solved by the invention]

[0012] SUMMARY OF THE INVENTION An object of the present invention is to prevent malfunctions caused by condensed water entering the intake manifold pressure introduction pipe in an engine system equipped with an exhaust gas recirculation device. [Means for solving the problem]

[0013] The present invention has been made to solve the above problems, and provides a gas fuel supply device for an engine, the gas fuel supply device comprising: a fuel cylinder that stores gas fuel; a regulator that reduces the pressure of the gas fuel; an intake passage that is provided with a throttle and a mixer in this order from the upstream side; a fuel pipe that supplies the gas fuel that has passed through the regulator to the mixer; an engine that burns the air-fuel mixture supplied through the intake passage in a cylinder and discharges exhaust gas from an exhaust passage; and an exhaust gas recirculation device that recirculates a portion of the exhaust gas as EGR gas from an EGR gas inlet to the intake passage, an intake pressure outlet formed in the intake passage; and a mounting portion formed around the intake pressure outlet, The regulator is characterized in that an intake pressure inlet is formed on its outer surface, and the regulator is fixed to the mounting part by a fixing member with the intake pressure outlet and the intake pressure inlet directly and airtightly connected to each other.

[0014] According to the present invention, the intake pressure outlet of the regulator in the intake passage is directly and airtightly connected to the intake pressure inlet of the regulator, thereby eliminating the need for the intake pipe pressure inlet pipe required in the prior art.

[0015] This not only prevents malfunctions caused by moisture entering the intake pressure introduction pipe, but also makes it easier to increase the diameter of the intake pressure introduction port because no structure for connecting the pipe is required.

[0016] In the present invention, when the intake passage includes an intake manifold that distributes the mixture to the cylinders and the intake pressure outlet is formed in the intake manifold, it is possible to extract and utilize the intake pressure just before it is supplied to each cylinder of the engine.

[0017] In the present invention, when the EGR gas inlet is formed between the throttle and the mixer and the intake pressure outlet is formed upstream of the EGR gas inlet, by extracting the intake pressure from upstream of the EGR gas inlet, it is possible to more reliably prevent condensed water from the exhaust gas recirculation device from entering the regulator.

[0018] In the present invention, when the intake pressure outlet is formed upstream of the throttle, by extracting the intake pressure from a location upstream of the throttle, it is possible to more reliably prevent condensed water from the exhaust gas recirculation system from entering the regulator. [Effects of the Invention]

[0019] According to the present invention, in a gas fuel supply device for an engine having a regulator with an intake pressure introduction function, it is possible to avoid malfunction of the intake pressure introduction function due to condensed water or the like. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing a first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of a main part showing the periphery of a regulator in the embodiment shown in FIG. 1. [Figure 3] FIG. 3 is a perspective view of FIG. 2. [Figure 4] FIG. 10 is a diagram showing a second embodiment of the present invention. [Figure 5] FIG. 10 is a diagram showing a third embodiment of the present invention. [Figure 6] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0022] First Embodiment FIG. 1 shows the configuration of a gas fuel supply device 100 for an engine according to a first embodiment of the present invention.

[0023] The engine gas fuel supply device 100 includes a fuel cylinder 1 storing gas fuel such as LPG, CNG, or hydrogen gas, a regulator 2 that reduces the pressure of the high-pressure gas fuel delivered from the fuel cylinder 1, an intake passage 5 equipped with a throttle 3 and a mixer 4 in that order from the upstream side, a fuel pipe 8 that supplies the gas fuel that has passed through the regulator 2 and reached a predetermined pressure to the mixer 4 via a fuel filter 6 and an injector 7, an engine 10 connected to an intake manifold 9 and an exhaust manifold 11, and an exhaust gas recirculation device 13.

[0024] The air supplied through the throttle 3 and the gas fuel supplied through the fuel pipe 8 are mixed in the mixer 4 to form an air-fuel mixture, which is distributed to each cylinder of the engine 10 by the intake manifold 9, and is ignited and combusted in each cylinder.

[0025] The exhaust gas discharged from each cylinder passes through an exhaust manifold 11 and is discharged to the outside through an exhaust passage 12.

[0026] In this specification, the entire intake system path leading to the engine 10, including the intake manifold 9, is defined as the intake passage 5, and the entire exhaust system path passing through the engine 10, including the exhaust manifold 11, is defined as the exhaust passage 12.

[0027] In this embodiment, an exhaust gas recirculation (EGR) device 13 is provided between the exhaust manifold 11 and the intake passage 5.

[0028] The exhaust gas recirculation device 13 comprises an EGR pipe 14, an EGR cooler 15, and an EGR valve 16, and is configured to recirculate a portion of the exhaust gas as EGR gas by returning it to the intake passage 5 side from an EGR gas inlet 17.

[0029] The EGR gas inlet 17 is provided in the intake passage 5 between the throttle 3 and the mixer 4 .

[0030] In addition, in this embodiment, a turbocharger 18 is provided that compresses the intake air by utilizing the flow of exhaust gas passing through the exhaust passage 12, and an intercooler 19 is provided that cools the compressed air.

[0031] FIG. 2 is a cross-sectional view of the regulator 2 and its periphery, and FIG. 3 is a perspective view thereof. The regulator 2 has a pressure regulating valve 21, which is made up of a cylindrical valve body 22 and an annular valve seat 23, inside a cylindrical main body 20.

[0032] The pressure regulating valve 21 reduces and adjusts the pressure of the high-pressure gas fuel being delivered from the fuel bottle 1 (in the direction of the black arrow shown in the figure) to a predetermined level by changing the distance between the valve body 22 and the valve seat 23 and adjusting the opening amount.

[0033] A piston 24 is fixed to the outer periphery of the valve body 22, and the valve body 22 and the piston 24 are displaceable in the axial direction.

[0034] The inside of the main body 20 is airtightly partitioned by a sealing member 221 that contacts the outer periphery of the valve body 22 and a sealing member 241 that contacts the outer periphery of the piston 24, and has a primary pressure chamber A on the inlet port 201 side, a secondary pressure chamber B on the outlet port 202 side, and a spring chamber C located between them.

[0035] In the spring chamber C, the piston 24 and a pressure adjusting spring 25 that biases the piston 24 toward the secondary pressure chamber B are provided.

[0036] The regulator 2 also has an inlet cover 26 attached to the introduction port 201 and an outlet cover 27 attached to the discharge port.

[0037] An intake pressure inlet 30 is formed on the outer surface of the main body 20, and has an intake pressure introduction function that introduces intake pressure, which is the pressure inside the intake passage 5, into the spring chamber C from the intake pressure inlet 30.

[0038] In this embodiment, an intake pressure outlet 40 is formed on the outer surface of the intake manifold 9, and a mounting portion 41 having a plurality of threaded holes is formed around the intake pressure outlet 40.

[0039] A seal member 42, which is an O-ring, is disposed around the intake pressure outlet 40.

[0040] The present invention is characterized in that the regulator 2 is fixed to the mounting portion 41 by a fixing member 31, which is a fixing screw, with the intake pressure outlet 40 and the intake pressure inlet 30 in direct and airtight communication.

[0041] The pressure regulation function of the regulator in this embodiment will be described below.

[0042] The gas fuel introduced from the fuel bottle 1 into the primary pressure chamber A passes through the valve body 22, which is in an open state by default, due to the biasing force of the pressure regulating spring 25 arranged in the spring chamber C, and moves to the secondary pressure chamber B.

[0043] When the pressure in the secondary pressure chamber B increases due to the gas fuel that has moved to the secondary pressure chamber B, the piston 24 is pushed down toward the primary pressure chamber A against the force of the pressure adjustment spring 25 that urges the piston 24 toward the secondary pressure chamber B.

[0044] Then, the intake pressure in the intake passage 5, which is introduced from the intake pressure inlet 30 through the intake pressure outlet 40, is introduced into the spring chamber C, causing the pressure in the spring chamber C to fluctuate, and this fluctuation acts on the piston 24.

[0045] In this way, the piston 24 is displaced in the axial direction due to the balance between the force of the pressure regulating spring 25 pushing the piston 24 toward the secondary pressure chamber B, the force of the gas fuel that has passed through the pressure regulating valve 21 and moved from the primary pressure chamber A to the secondary pressure chamber B pushing the piston 24 toward the primary pressure chamber A, and the pressure in the spring chamber C that fluctuates depending on the introduced intake pressure, thereby opening and closing the pressure regulating valve 21 and regulating the pressure.

[0046] According to this embodiment, the intake pressure outlet 40 and the intake pressure inlet 30 are directly and airtightly connected, thereby eliminating the need for the intake pipe pressure inlet pipe used in the prior art.

[0047] This not only prevents malfunctions caused by moisture entering the intake pressure introduction pipe, but also makes it easier to increase the diameter of the intake pressure introduction port 30 since no pipe connection structure is required.

[0048] The advantage of increasing the diameter of the intake pressure inlet 30 is that it improves the response when introducing intake pressure, and even if condensed water adheres to the inner surface of the intake pressure inlet 30, there is no need to worry about malfunction of the intake pressure introduction function because the diameter is larger than that of the intake pipe pressure introduction pipe of the conventional example.

[0049] Second Embodiment Figure 4 shows a gas fuel supply device 200 for an engine, which is a second embodiment of the present invention, and is basically the same as the first embodiment shown in Figure 1, with the same structures being given the same symbols, except that the intake pressure outlet 50 is formed in the intake passage 5 upstream of the EGR gas inlet 17 and downstream of the throttle 3.

[0050] In this embodiment, an intake pressure outlet 50 is formed on the outer surface of the intake passage 5 upstream of the intake manifold 9. Similarly to the mounting portion 41 having a plurality of threaded holes formed around the intake pressure outlet 40 in FIG. 2 , a mounting portion 41 having a plurality of threaded holes is formed around the intake pressure outlet 50, and a sealing member 42 which is an O-ring is disposed around the intake pressure outlet 50.

[0051] The regulator 2 is fixed to the mounting portion 41 by a fixing member 31, which is a fixing screw, with the intake pressure outlet 50 formed in the intake passage 5 and the intake pressure inlet 30 of the regulator 2 directly and airtightly connected to each other.

[0052] Since the EGR gas containing moisture sent from the exhaust gas recirculation device 13 moves downstream from the EGR gas inlet 17 toward the engine 10, by forming the intake pressure outlet 50 at a position upstream of the EGR gas inlet 17, condensed water can be prevented from entering through the intake pressure outlet 40.

[0053] Third Embodiment Figure 5 shows a gas fuel supply device 300 for an engine, which is a third embodiment of the present invention, and is basically the same as the first embodiment shown in Figure 1, with the same structures being given the same symbols, except that the intake pressure outlet 60 is formed upstream of the EGR gas inlet 17 in the intake passage 5 and upstream of the throttle 3.

[0054] In this embodiment, an intake pressure outlet 60 is formed on the outer surface of the intake passage 5 upstream of the intake manifold 9. Similarly to the mounting portion 41 having a plurality of threaded holes formed around the intake pressure outlet 40 in Figure 2, a mounting portion 41 having a plurality of threaded holes is formed around the intake pressure outlet 60, and a sealing member 42 which is an O-ring is arranged around the intake pressure outlet 60.

[0055] The regulator 2 is fixed to the mounting portion 41 by a fixing member 31, which is a fixing screw, with the intake pressure outlet 60 formed in the intake passage 5 and the intake pressure inlet 30 of the regulator 2 directly and airtightly connected to each other.

[0056] The moisture-containing EGR gas sent from the exhaust gas recirculation device 13 moves downstream from the EGR gas inlet 17 toward the engine 10, and passes through the throttle 3. Therefore, by forming the intake pressure outlet 60 at a position upstream of the EGR gas inlet 17, it is possible to more reliably prevent condensed water from entering through the intake pressure outlet 60.

[0057] In addition, since the first to third embodiments shown in this specification are engine systems having a turbocharger, the intake pressure in the intake passage fluctuates between negative pressure, atmospheric pressure, and positive pressure depending on the operating conditions of the turbocharger.

[0058] On the other hand, in a naturally aspirated engine system that does not have a turbocharger, the intake pressure in the intake passage fluctuates between negative pressure and atmospheric pressure due to the influence of intake pulsation, for example.

[0059] Even if such fluctuations in intake pressure occur, the present invention, which directly and airtightly connects the intake pressure outlet formed in the intake passage with the intake pressure inlet formed in the regulator, still demonstrates the intake pressure introduction function within the intake passage, but does not require an intake pipe pressure introduction pipe as in conventional inventions.This makes it easy to increase the diameter of the intake pressure introduction port while avoiding problems with the intake pressure introduction function due to condensation, etc.

[0060] Although the first to third embodiments shown in this specification are engine systems having a turbocharger, the present invention can also be implemented in a naturally aspirated engine system that does not have a turbocharger. [Explanation of symbols]

[0061] 1 fuel tank 2 regulators 3 Throttle 4. Mixer 5 Intake passage 6 Fuel Filter 7 Injectors 8 Fuel piping 9. Intake manifold 10 Engine 11 Exhaust manifold 12 Exhaust passage 13 Exhaust Gas Recirculation System 14 EGR piping 15 EGR cooler 16 EGR valve 17 EGR gas inlet 18 Turbocharger 19 Intercooler 20 Main Unit 201 Introduction Port 202 Discharge port 21 Pressure Regulating Valve 22 Valve body 221 Sealing material 23 Valve seat 24 pistons 241 Sealing material 25 Pressure adjusting spring 26 Entrance cover 27 Exit cover 30 Intake pressure inlet 31 Fixing member 40 Intake pressure outlet 41 Mounting part 42 Sealing material 50 Intake pressure outlet 60 Intake pressure outlet 100 Engine gas fuel supply device 200 Engine gas fuel supply system 300 Engine Gas Fuel Supply System A Primary pressure chamber B Secondary pressure chamber C Back pressure chamber

Claims

1. a fuel cylinder storing gas fuel; a regulator that reduces the pressure of the gas fuel; an intake passage provided with a throttle and a mixer in this order from the upstream side; a fuel pipe that supplies the gas fuel that has passed through the regulator to the mixer; an engine that burns the air-fuel mixture supplied through the intake passage in a cylinder and discharges exhaust gas from an exhaust passage; an exhaust gas recirculation device that recirculates a portion of the exhaust gas as EGR gas from an EGR gas inlet to the intake passage, an intake pressure outlet formed in the intake passage; a mounting portion formed around the intake pressure outlet, the regulator has an intake pressure inlet formed on its outer surface; the regulator is fixed to the mounting portion by a fixing member in a state in which the intake pressure outlet and the intake pressure inlet are directly and airtightly communicated with each other; A gas fuel supply device for an engine.

2. the intake passage includes an intake manifold that distributes the air-fuel mixture to the cylinders, The intake pressure outlet is formed in the intake manifold.

2. The gas fuel supply system for an engine according to claim 1.

3. the EGR gas inlet is formed between the throttle and the mixer, The intake pressure outlet is formed upstream of the EGR gas inlet.

2. The gas fuel supply system for an engine according to claim 1.

4. The intake pressure outlet is formed upstream of the throttle.

4. The gas fuel supply system for an engine according to claim 3.

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