JP2017115727A - Work vehicle mounted with engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel system in which fuel is uniformly supplied to an engine from a plurality of fuel tanks, and in which residual amounts of fuels in the plurality of fuel tanks become the same as far as possible.SOLUTION: A fuel supply path 67 is formed, which is composed of: a first fuel supply path 671 connecting a first fuel tank 61 and a merging portion 65; a second fuel supply path 672 connecting a second fuel tank 62 and the merging portion 65; and a common supply path 670 connecting the merging portion 65 and an engine 3. In the common supply path 670, a fuel pump 60 for supplying a fuel to the engine 3 is provided. Check valves 63 and 64 opened according to differential pressure between fuel tank side pressure and merging portion side pressure are interposed between the first fuel supply path 671 and the second fuel supply path 672. A communication channel 70 is formed, which communicates a top portion space S1 of the first fuel tank 61 and a top portion space S2 of the second fuel tank 62.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a work vehicle equipped with an engine to which fuel is supplied from a plurality of fuel tanks.

  In the fuel tank system for an agricultural tractor disclosed in Patent Document 1, the upper portions of the right fuel tank and the left fuel tank are communicated with each other by an air circulation pipe, and the bottom portions of the right fuel tank and the left fuel tank are coupled by a fuel take-out pipe. The pump suction pipe branches off from the center of the fuel extraction pipe. A fuel pump is provided in the pump suction pipe, and fuel is supplied from the fuel supply pump to the engine.

Utility Model Registration Gazette No. 2563729 (FIGS. 1 and 4)

  When a plurality of fuel tanks are mounted, it is desired that the residual fuel in each fuel tank be reduced in the same manner in consideration of the weight balance in the work vehicle. Therefore, for example, by providing a fuel switching cock and selecting a fuel tank to be used as needed, it is possible to make each residual fuel as similar as possible. However, operating the fuel switching cock at any time places a burden on the driver. From this, it is possible to construct a fuel system in which fuel is uniformly supplied from a plurality of fuel tanks to the engine by keeping the internal pressure of each fuel tank uniform while omitting the fuel switching cock. There is a demand for a technology that makes the fuels as similar as possible.

  A work vehicle equipped with an engine according to the present invention includes a first fuel tank, a second fuel tank, a first fuel supply path that connects the first fuel tank and the merging portion, the second fuel tank, and the merging portion. A fuel supply path composed of a second fuel supply path that connects to the engine, a common supply path that connects the junction and the engine, and fuel from the first fuel tank and the second fuel tank provided in the common supply path A fuel pump that supplies fuel to the engine, a first check valve that is interposed in the first fuel supply path and that opens according to a differential pressure between the fuel tank side pressure and the merging portion side pressure, and the second A second check valve interposed in the fuel supply path and opened in accordance with a differential pressure between the fuel tank side pressure and the merging portion side pressure; a top space of the first fuel tank; and a top portion of the second fuel tank Communicate with space And a communication passage.

  According to this configuration, in order to supply fuel to the diesel engine, fuel is sucked from the first fuel tank and the second fuel tank via the check valve by the common fuel pump. At that time, since a check valve is interposed in the fuel supply path, if there is a pressure difference due to the difference in the storage amount between the first fuel tank and the second fuel tank, the larger pressure, that is, the storage amount is large. More fuel is drawn from the other fuel tank. Therefore, it is important that the difference in supply pressure between the first fuel tank and the second fuel tank is caused only by the difference in the fuel storage amount. For example, if there is a difference in tank internal pressure due to variations in the accuracy of the fuel cap that closes the fuel filler opening of the fuel filler, fuel may be drawn from only one fuel tank. Such an inconvenience is solved by balancing the internal pressures of the respective internal pressures by the communication flow path that connects the top space of the first fuel tank and the top space of the second fuel tank. Thereby, it is avoided that a difference occurs in the storage amount between the first fuel tank and the second fuel tank.

  The communication channel needs to open to a space above the liquid level of the fuel, and a place that satisfies this condition is the vicinity of the fuel supply part forming the fuel supply port. For this reason, one end of the communication flow path opens at a position adjacent to the fuel supply part of the first fuel tank, and the other end of the communication flow path opens at a position adjacent to the fuel supply part of the second fuel tank. Convenient.

  Since the fuel is heavy, in order that the first fuel tank and the second fuel tank do not adversely affect the weight balance of the vehicle, it is preferable to arrange them separately on the right side and the left side of the vehicle. In that case, it is preferable to arrange | position a communicating flow path in the place which does not interfere with movement of a driver | operator etc. and installation of another apparatus, with little interference with another member. For this reason, in a preferred embodiment of the present invention, the first fuel tank and the second fuel tank are spaced apart on the right side and the left side of the driver seat, and the communication flow path passes behind the driver seat. . From the viewpoint of protecting the communication flow path, the communication flow path is preferably formed of a rubber hose and is surrounded by a metal pipe such as a steel pipe.

  When the engine is a diesel engine, it is necessary to return a part of the fuel supplied by the fuel pump to the fuel tank. Therefore, a fuel return path for returning surplus fuel from the diesel engine to the first fuel tank and the second fuel tank is provided. It has been. At that time, in order not to cause a large difference in the storage amount (remaining fuel amount) between the first fuel tank and the second fuel tank, the amount of fuel returned from the diesel engine to the first fuel tank and the second fuel tank is also increased. It is desirable to be as equal as possible. Therefore, in one of the preferred embodiments of the present invention, the fuel return path includes a common return path that connects the engine and the branch section, a first fuel return path that connects the branch section and the first fuel tank, and a branch section. And a second fuel return path connecting the second fuel tank and a second fuel return path formed in the second fuel tank and a return port of the first fuel return path formed in the first fuel tank. Are set at the same height (including almost the same height) at the fuel tank. In this configuration, the fuel returned from the diesel engine branches at the branch portion, and each branched fuel returns to the first fuel tank and the second fuel tank. Therefore, if the amount of storage in one of the fuel tanks increases, for example, when the state for closing the return port is reached, the pressure in the fuel return path rises, so the fuel returned from the diesel engine is in another fuel tank. It is avoided that only one fuel tank is full. In this embodiment, both return ports are at approximately the same height level, which means a height level that is guaranteed to prevent only one fuel tank from becoming full. .

  In order to make the ratio of fuel returned from the diesel engine to the first fuel tank and the second fuel tank as equal as possible, the flow resistance of the fuel in the first fuel return path and the second fuel return path is substantially reduced. It should be the same. For example, the difference between the two is preferably within 0% to 20%. One suitable measure for this is to make the first fuel return path and the second fuel return path substantially the same in flow cross-sectional area and flow path length. For example, it is preferable that a difference in flow cross-sectional area and a difference in flow path length between the first fuel return path and the second fuel return path are within 0% to 20%.

It is a schematic diagram explaining the basic principle of the fuel distribution | circulation in this invention. It is a side view of the zero turn mower which is one of the specific embodiments of the work vehicle of the present invention. It is a top view of a zero turn mower. It is a front view showing typically distribution of fuel between the 1st fuel tank, the 2nd fuel tank, and the engine.

  Before describing a specific embodiment of a work vehicle according to the present invention, a basic configuration of fuel flow between a fuel tank and an engine employed in the present invention will be described with reference to FIG. The engine 3 mounted on the work vehicle receives fuel from a pair of left and right first fuel tanks 61 and second fuel tanks 62. The first fuel tank 61 and the second fuel tank 62 have substantially the same shape, but need not be the same. The first fuel tank 61 and the second fuel tank 62 and the fuel supply port 67A of the engine 3 are connected by a fuel supply path 67 generally constituted by a fuel hose. The fuel supply path 67 includes a first fuel supply path 671 that connects the first fuel tank 61 and the junction 65, a second fuel supply path 672 that connects the second fuel tank 62 and the junction 65, and a junction 65 and a common supply path 670 that connects the fuel supply port 67A of the engine 3. A first check valve 63 is interposed in the first fuel supply path 671, and a second check valve 64 is interposed in the second fuel supply path 672. A fuel pump 60 is interposed in the common supply path 670. The first check valve 63 and the second check valve 64 are opened in accordance with a differential pressure between the fuel tank side pressure and the merging portion side pressure. That is, when negative pressure is generated in the merging portion 65 by driving the fuel pump 60, the first check valve 63 and the second check valve 64 are opened, and fuel is commonly supplied from the first fuel tank 61 and the second fuel tank 62. It flows into the path 670.

  When the fuel pump 60 is driven, the pressure between the merging portion 65 of the first fuel supply path 671 and the first check valve 63 is changed by the suction force of the fuel pump 60 to the first check valve 63 and the first fuel tank 61. Therefore, the first check valve 63 is opened, and the fuel is supplied from the first fuel tank 61 to the engine 3. Similarly, fuel is supplied from the second fuel tank 62 to the engine 3. However, when the amount of fuel stored in either the first fuel tank 61 or the second fuel tank 62 is large, the pressure difference in the check valve on the side corresponding to this increases, and the valve opening amount increases. As a result, the fuel is mainly sucked into the fuel pump 60 from the fuel tank having the larger fuel storage amount. That is, the amount of fuel stored in the first fuel tank 61 and the second fuel tank 62 is balanced by the hydraulic pressure difference between the fuel stored in the first fuel tank 61 and the second fuel tank 62.

  On the ceiling surface of the first fuel tank 61 and the second fuel tank 62, a fuel supply section 9 having a fuel supply port 91 closed by a fuel supply cap 90 is formed. Due to individual differences and tightening conditions of the fuel cap 90, if a difference occurs in the internal pressure of the first fuel tank 61 and the second fuel tank 62 due to the fuel supply to the engine 3, the liquid pressure of the fuel is affected. This makes it impossible to balance the fuel storage amount due to the difference in fuel pressure. For this reason, a communication flow path 70 that communicates the top space S1 of the first fuel tank 61 and the top space S2 of the second fuel tank 62 is provided. One end of the communication flow path 70 is open at a position adjacent to the fuel supply section 9 of the first fuel tank 61, and the other end of the communication flow path 70 is positioned at a position adjacent to the fuel supply section 9 of the second fuel tank 62. It is open. Thereby, the internal pressures of the first fuel tank 61 and the second fuel tank 62 are kept substantially the same.

  In the example of FIG. 1, since a diesel engine is employed as the engine 3, a fuel hose is generally formed between the first fuel tank 61 and the second fuel tank 62 and the fuel return port 68 </ b> A of the engine 3. It is connected by a fuel return path 68. The fuel return path 68 includes a common return path 680 that connects the fuel return port 68A of the engine 3 and the branch portion 66, and a first fuel return path 681 that connects the branch portion 66 and the return port 68a of the first fuel tank 61. And a second fuel return path 682 connecting the branch portion 66 and the return port 68a of the second fuel tank 62. The return port 68a formed in the first fuel tank 61 and the return port 68a formed in the second fuel tank 62 have substantially the same height level in each fuel tank. In order to make the fuel flow resistance in the first fuel return path 681 and the second fuel return path 682 substantially the same, the first fuel return path 681 and the second fuel return path 682 have substantially the same flow cross-sectional area and It has a channel length. Therefore, for example, when the return fuel flows into the first fuel tank 61 and reaches the return port 68a of the first fuel tank 61, the pressure in the first fuel return path 681 increases. As a result, most of the fuel returned from the engine 3 flows into the second fuel tank 62 at the branch portion 66.

  The adjustment of the return fuel as described above is performed by the float valve 69 that closes when the fuel level exceeds a certain value at the return port 68a of the first fuel return path 681 and the return port 68a of the second fuel return path 682. By providing this, it becomes more reliable.

  Next, one specific embodiment of the work vehicle according to the present invention will be described with reference to the drawings. This work vehicle is a riding mower equipped with a mower unit 13 as a work device. FIG. 2 is a side view of the riding mower, and FIG. 3 is a plan view. This riding mower is also called a zero-turn mower, and includes a vehicle body 10 supported by a pair of left and right front wheels 11 and a pair of left and right rear wheels 12 as drive wheels that are independently driven to rotate. ing. The vehicle body 10 has a vehicle body frame 2 as a base member, and a mower unit 13 is suspended from the vehicle body frame 2 via a link mechanism 14 between a front wheel 11 and a rear wheel 12. The driving unit 5 is arranged in the vehicle longitudinal direction central region of the vehicle body 10. A lops device 6 is provided at the rear of the driving unit 5. An engine 3 that is a diesel engine is disposed in the rear end region of the vehicle body 10. An engine accessory such as a radiator 31 is disposed in front of the engine 3, and the engine 3 and the engine accessory are covered with a bonnet 30 from above. A seat support 52 is formed in the region of the driving section 5 of the vehicle body 10, and a driver seat 53 is provided on the upper surface of the seat support 52. Further, fenders 54 are formed on the left and right side surfaces of the seat support 52. A step 51 is laid in front of the driver seat 53. A first fuel tank 61 is disposed below the left fender 54 along the peripheral surface of the rear wheel 12, and below the right fender 54, a first fuel tank 61 is disposed along the peripheral surface of the rear wheel 12. Two fuel tanks 62 are arranged. The first fuel tank 61 and the second fuel tank 62 have substantially the same shape and dimensions, and extend rearward from the side of the driver seat 53 beyond the lops device 6 in the longitudinal direction of the vehicle body. An oil supply section 9 is provided on the upper surface of the rear portion of the first fuel tank 61 and the second fuel tank 62 beyond the lops device 6. The oil supply unit 9 includes an oil supply cylinder 610 that protrudes substantially vertically from the upper surface part, and an oil supply cap 90 that covers the oil supply port of the oil supply cylinder 610.

  The fuel system including the first fuel tank 61 and the second fuel tank 62 employs the basic configuration described with reference to FIG. The communication flow path 70 that connects the first fuel tank 61 and the second fuel tank 62 is configured as a communication pipe in which a rubber hose is surrounded by a metal pipe (for example, a steel pipe), and the seat back 53 b of the driver seat 53 and the hood 30. It is laid between the front wall.

  A transmission 4 is disposed on the front side of the engine 3. The transmission 4 includes a pair of left and right rear axle transmission units 41. Each of the left and right rear axle transmission units 41 includes a hydrostatic transmission (hereinafter abbreviated as HST42) that can be operated independently as an example of a continuously variable transmission. The HST 42 can continuously change the engine power from the low speed to the high speed in the normal rotation (forward) state and the reverse rotation (reverse) state, and can transmit the power to the respective rear wheels 12. Thus, both the left and right rear wheels 12 are driven in the forward direction at the same or substantially the same speed to produce a straight forward advance, and the left and right rear wheels 12 are driven in the reverse direction at the same or substantially the same speed to go straight. A reverse is created. Furthermore, by making the speeds of the left and right rear wheels 12 different from each other, the vehicle body 10 can be turned in an arbitrary direction. For example, either one of the left and right rear wheels 12 is set to a low speed close to zero speed, The other rear wheel 12 can be turned in a small turn by operating the rear wheel 12 forward or backward at high speed. Further, by driving the left and right rear wheels 12 in opposite directions, the vehicle body 10 can be spin-turned with the substantially central portion of the left and right rear wheels 12 as the turning center. Since the pair of left and right front wheels 11 are configured as caster wheels and can be freely changed in direction around the longitudinal axis, the directions are corrected according to the traveling direction by driving the left and right rear wheels 12.

  The shifting operation for the left and right HSTs 42 is performed by a pair of left and right shifting levers 49 disposed on both sides of the driver seat 53. When the transmission lever 49 is held in the front-rear neutral position, the continuously variable transmission is in a neutral stop state, and the forward shift is realized by operating the transmission lever 49 forward from the neutral position, and the reverse transmission is realized by operating the transmission lever 49 backward. .

  As is apparent from FIG. 3, the vehicle body frame 2 includes a pair of left and right front frames 21 and a pair of left and right rear frames 22. The left and right front frames 21 are connected by a front cross beam unit 26 including a plurality of cross beams. Has been. Similarly, the left and right rear frames 22 are connected by a rear cross beam unit including a plurality of cross beams, but the illustration of the rear cross beam units is omitted. An engine mount region is formed in the rear end region of the rear frame 22.

  The front cross beam unit 26 located at the front end of the vehicle body 10 is provided with a front wheel support arm 28 extending in the vehicle transverse direction. An inverted U-shaped front guard 29 is erected in the center of the front wheel support arm 28. The front wheel 11 is attached to both ends of the front wheel support arm 28 via caster brackets 110.

  FIG. 4 is a fuel distribution system diagram of this mower. The principle explained with reference to FIG. 1 is used for fuel distribution in this mower. The structural features are that the bottom surface of the first fuel tank 61 and the bottom surface of the second fuel tank 62 are located above the crankshaft 3 a of the engine 3, and the first fuel supply path 671 is the bottom surface of the first fuel tank 61. The second fuel supply path 672 is connected at the bottom surface of the second fuel tank 62. Further, the first fuel tank 61 and the second fuel tank 62 are communicated with each other through a communication channel 70. Further, the first fuel return path 681 is connected to the upper surface of the first fuel tank 61, and the second fuel return path 682 is connected to the upper surface of the second fuel tank 62. A filter 6 a is interposed between the first fuel tank 61 and the first check valve 63 and between the first fuel tank 61 and the first check valve 63.

  As described above, the top space S1 of the first fuel tank 61 and the top space S2 of the second fuel tank 62 communicate with each other by the communication flow path 70 whose main portion extends substantially horizontally. The internal pressure is balanced. However, when multiple safety is taken into consideration, the fuel cap 90 may have a structure in which the tank internal pressure is maintained at atmospheric pressure. For example, the internal pressure of the first fuel tank 61 and the second fuel tank 62 is always kept at atmospheric pressure by providing a filter film that allows air to pass but does not allow fuel to pass between the fuel cap 90 and the fuel cylinder 610. It is.

[Another embodiment]
(1) In the embodiment described above, the engine 3 is disposed at the rear portion of the vehicle body 10, but the engine 3 may be disposed at the front portion of the vehicle body 10 and the transmission 4 may be disposed behind the engine 3.
(2) In the above-described embodiment, the mid-mount type in which the mower unit 13 is disposed between the front wheel 11 and the rear wheel 12 is employed, but the front mount in which the mower unit 13 is disposed in front of the front wheel 11. It is also possible to adopt a formula.
(3) In the above-described embodiment, the front wheel 11 is a caster wheel, but it may be a steering wheel operated by a steering wheel. In that case, the left and right rear wheels 12 receive the output from the same transmission branched by the differential mechanism via the differential mechanism.
(4) In the above-described embodiment, a working vehicle equipped with the mower unit 13 as a working device, that is, a riding mower is taken up. Instead of this, it is also possible to mount a spraying device, a snow removal device, a planting device, a harvesting device or the like as the working device.

  The present invention can be applied to a work vehicle including an engine and a plurality of fuel tanks.

3: Engine 53: Driver's seat 6a: Filter 60: Fuel pump 61: First fuel tank 62: Second fuel tank 63: First check valve 64: Second check valve 65: Junction portion 66: Branch portion 67: Fuel supply Path 67A: Fuel supply port 670: Common supply path 671: First fuel supply path 672: Second fuel supply path 68: Fuel return path 68A: Fuel return port 68a: Return port 680: Common return path 681: First fuel return Path 682: Second fuel return path 70: Communication path 9: Refueling part S1: Top space S2: Top space

Claims (7)

A work vehicle equipped with an engine,
A first fuel tank;
A second fuel tank;
A first fuel supply path connecting the first fuel tank and the merge section; a second fuel supply path connecting the second fuel tank and the merge section; and a common supply path connecting the merge section and the engine. A fuel supply path;
A fuel pump provided in the common supply path for supplying fuel from the first fuel tank and the second fuel tank to the engine;
A first check valve that is interposed in the first fuel supply path and opens in accordance with a differential pressure between the fuel tank side pressure and the merging portion side pressure;
A second check valve interposed in the second fuel supply path and opened in accordance with a differential pressure between the fuel tank side pressure and the junction side pressure;
A work vehicle provided with a communication channel that communicates the top space of the first fuel tank and the top space of the second fuel tank.   One end of the communication flow path opens at a position adjacent to the fuel supply part of the first fuel tank, and the other end of the communication flow path opens at a position adjacent to the fuel supply part of the second fuel tank. The work vehicle according to claim 1.   The said 1st fuel tank and the said 2nd fuel tank are arrange | positioned away on the right side and the left side of a driver's seat, and the said communication flow path has passed the said driver's seat behind. Work vehicle.   The work vehicle according to any one of claims 1 to 3, wherein the communication channel includes a rubber hose and a metal pipe that surrounds the rubber hose.   The operation according to any one of claims 1 to 4, wherein the engine is a diesel engine, and a fuel return path is provided for returning surplus fuel from the diesel engine to the first fuel tank and the second fuel tank. vehicle.   The fuel return path connects a common return path that connects the diesel engine and the branch section, a first fuel return path that connects the branch section and the first fuel tank, and connects the branch section and the second fuel tank. A return port of the first fuel return path formed in the first fuel tank and a return port of the second fuel return path formed in the second fuel tank. The work vehicle according to claim 5, wherein each fuel tank is set at the same height level.   The bottom surface of the first fuel tank and the bottom surface of the second fuel tank are located above the crankshaft of the diesel engine, and the first fuel supply path is connected at the bottom surface of the first fuel tank, The second fuel supply path is connected at the bottom surface of the second fuel tank, and the fuel return path is connected at the top surfaces of the first fuel tank and the second fuel tank. Work vehicle.

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