JP7552486B2 - Fuel supply system for internal combustion engine - Google Patents

Description

The present invention relates to a fuel supply system for an internal combustion engine.

There is a known fuel delivery pipe that allows bubbles of air or fuel vapor that have accumulated inside the fuel delivery pipe to be quickly discharged through a fuel injection valve. A conventional example of this type of fuel delivery pipe is described in Patent Document 1.

The fuel delivery pipe described in Patent Document 1 has an uppermost portion located vertically above the other portions in the fuel storage chamber of the fuel delivery pipe, and a bubble guide surface extending diagonally upward toward the uppermost portion is formed by a spacer attached to the upper portion of the fuel storage chamber.

A fuel delivery pipe configured in this manner uses the bubble guide surface to collect air bubbles at the top of the fuel holding chamber, and supplies the air bubbles to the fuel injection valve through a connecting passage provided at the top of the fuel holding chamber, allowing the air bubbles to be quickly expelled outside the fuel holding chamber.

Japanese Patent Application Publication No. 11-280594

However, in the case of a vertically mounted engine that has a crankshaft that extends in the fore-and-aft direction of the vehicle and is mounted on the vehicle with this crankshaft tilted backward, the delivery pipe that supplies fuel to the fuel injection valve also tilts backward, so the front end of the delivery pipe is at the top in the vertical direction.

In this case, the gap between the front end of the delivery pipe and the vehicle body components located above it, such as the floor panel and bonnet, is reduced, which may cause interference between the delivery pipe and the vehicle body components.

In addition, if the uppermost portion of the ceiling wall of the delivery pipe is installed at a position above the fuel inlet of the fuel injection valve, it may become difficult for the air bubbles collected at the top to be supplied to the fuel inlet by the fuel flow.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a fuel supply device for an internal combustion engine that improves the mountability of the delivery pipe on a vehicle and can quickly expel air bubbles generated in the delivery pipe to the outside when a delivery pipe is used to supply fuel to a fuel injection valve mounted on the top of an internal combustion engine having a backward-inclined crankshaft.

The present invention relates to a fuel supply device for an internal combustion engine having a plurality of cylinders arranged in the longitudinal direction of a vehicle, and a crankshaft extending in the longitudinal direction of the vehicle and tilted backward so that its front end is located higher than its rear end, the device comprising: a plurality of fuel injection valves provided in an upper portion of the internal combustion engine for injecting fuel into each of the plurality of cylinders; and a delivery pipe having a fuel passage extending in the longitudinal direction of the vehicle and supplying fuel to the plurality of fuel injection valves, the delivery pipe having a bottom wall in which a fuel discharge port is formed for discharging fuel to a fuel inlet of the plurality of fuel injection valves, and a ceiling wall facing the bottom wall in the vertical direction, the front end of the delivery pipe being in the form of a fuel injection valve. The ceiling wall is inclined backward so as to be positioned above the rear end of a delivery pipe, and when the fuel injection valve located at the frontmost position in the fore-and-aft direction of the vehicle among the multiple fuel injection valves is defined as a front fuel injection valve, the ceiling wall has a rear upper portion of the front fuel injection valve which is the uppermost portion in the vertical direction, and a portion forward of the uppermost portion is located below an imaginary horizontal plane which is in contact with the uppermost portion and in the vicinity of the imaginary horizontal plane , the ceiling wall has a rear ceiling wall portion which extends from the rear end of the ceiling wall to the uppermost portion, and an inclined wall portion which extends diagonally downward to the front from the uppermost portion, and the front fuel injection valve is located forward of the inclined wall portion .

As described above, according to the present invention, when a delivery pipe is used to supply fuel to a fuel injection valve mounted on the top of an internal combustion engine having a backward-inclined crankshaft, the ease of mounting the delivery pipe on the vehicle can be improved, and air bubbles generated inside the delivery pipe can be quickly discharged to the outside.

FIG. 1 is a right side view of an upper portion of an internal combustion engine equipped with a fuel supply system according to an embodiment of the present invention. FIG. 2 is an enlarged plan view of a fuel supply system for an internal combustion engine according to one embodiment of the present invention. 3 is a cross-sectional view taken along the line III-III in FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. FIG. 5 is an enlarged cross-sectional view of the front portion of the delivery pipe.

The fuel supply device for an internal combustion engine according to one embodiment of the present invention is a fuel supply device for an internal combustion engine having a plurality of cylinders arranged in the longitudinal direction of a vehicle and a crankshaft extending in the longitudinal direction of the vehicle and tilted backward so that the front end is located higher than the rear end. The fuel supply device is provided with a plurality of fuel injection valves provided in the upper part of the internal combustion engine and injecting fuel into each of the plurality of cylinders, and a delivery pipe having a fuel passage extending in the longitudinal direction of the vehicle and supplying fuel to the plurality of fuel injection valves. The delivery pipe has a bottom wall having a fuel discharge port for discharging fuel to the fuel inlets of the plurality of fuel injection valves and a ceiling wall facing the bottom wall in the vertical direction, and is tilted backward so that the front end of the delivery pipe is located higher than the rear end of the delivery pipe. When the fuel injection valve located at the frontmost position in the longitudinal direction of the vehicle among the plurality of fuel injection valves is defined as the front fuel injection valve, the upper rear part of the ceiling wall is the uppermost part in the vertical direction, and the part forward of the uppermost part is located below an imaginary horizontal plane that contacts the uppermost part and in the vicinity of the imaginary horizontal plane.

As a result, when a fuel supply device for an internal combustion engine according to one embodiment of the present invention is used with a delivery pipe that supplies fuel to a fuel injection valve mounted on the top of an internal combustion engine having a backward-inclined crankshaft, the delivery pipe can be easily mounted on a vehicle and air bubbles generated within the delivery pipe can be quickly expelled to the outside.

Below, a fuel supply device for an internal combustion engine according to one embodiment of the present invention will be described with reference to the drawings. Figures 1 to 5 are diagrams showing a fuel supply device for an internal combustion engine according to one embodiment of the present invention.

In Figures 1 to 5, the up/down, front/rear, left/right directions are based on the internal combustion engine mounted on the vehicle, and the front/rear direction of the vehicle (straight ahead) is defined as the front/rear direction, the left/right direction of the vehicle (vehicle width direction) is defined as the left/right direction, and the up/down direction of the vehicle (vehicle height direction) is defined as the up/down direction.

First, the configuration will be described.
In FIG. 1, an engine 1 as an internal combustion engine mounted on a vehicle includes a cylinder block 2, a cylinder head 3, a cylinder head cover 4, and an oil pan 5.

The cylinder block 2 has three cylinders 2A, 2B, and 2C, which are arranged in series in the front-rear direction with their respective central axes inclined so that the intake ports 2D, 2E, and 2F face upward. The intake ports 2D, 2E, and 2F are connected to branch passages (upstream intake ports) 8A, 8B, and 8C formed in a branch pipe of the intake manifold (not shown).

Engine 1 is provided with a crankshaft 2S that extends in the front-to-rear direction. In this embodiment, engine 1 is a front-engine, rear-wheel drive (FR) type vertically mounted engine.

Note that engine 1 is not limited to an in-line three-cylinder engine, but may be, for example, a V-type engine, and the number of cylinders is not limited to three.

The engine 1 is installed, for example, below a vehicle body member 10 formed by a floor panel. The vehicle body member 10 may be formed by an engine hood, and the engine 1 may be installed below the engine hood.

The cylinder head 3 is provided on top of the cylinder block 2. The cylinder head 3 has intake ports 2D, 2E, and 2F, exhaust ports (none of which are shown), intake valves that open and close the intake ports 2D, 2E, and 2F, and exhaust valves that open and close the exhaust ports.

The cylinder head cover 4 is provided on top of the cylinder head 3. In the space between the cylinder head 3 and the cylinder head cover 4, an intake camshaft (not shown) having an intake cam (not shown) that opens and closes the intake valve, and an exhaust camshaft (not shown) having an exhaust cam (not shown) that opens and closes the exhaust valve are installed.

The oil pan 5 is located at the bottom of the cylinder block 2 and stores oil for lubricating the engine 1.

The crankshaft 2S is tilted backward so that the front end 2f is positioned higher than the rear end 2r, and the engine 1 is tilted backward as a whole in accordance with the tilt of the crankshaft 2S. Pistons (not shown) are housed in the cylinders 2A, 2B, and 2C, and the pistons are connected to the crankshaft 2S via connecting rods (not shown).

The reciprocating motion of the pistons is converted into the rotational motion of the crankshaft 2S via the connecting rod. The crankshaft 2S is tilted backward so that the front end 2f is located higher than the rear end 2r, so the frontmost cylinder 2A is located at the highest position, and the cylinders 2A, 2B, and 2C are located in the lower positions in that order.

Injectors 6A, 6B, and 6C are installed in the cylinder head 3 located at the top of the engine 1, and the injectors 6A, 6B, and 6C are installed along the arrangement direction of the cylinders 2A, 2B, and 2C.

Injectors 6A, 6B, and 6C are provided for cylinders 2A, 2B, and 2C, respectively, and inject fuel into intake ports 2D, 2E, and 2F that communicate with cylinders 2A, 2B, and 2C. In this embodiment, injectors 6A, 6B, and 6C constitute fuel injection valves. Of injectors 6A, 6B, and 6C, injector 6A, which is located at the forefront, constitutes a front fuel injection valve.

The engine 1 is provided with a delivery pipe 7. The delivery pipe 7 has a fuel passage 7a that extends in the front-rear direction (see FIG. 4), and fuel is supplied to the fuel passage 7a from a fuel tank (not shown) through a fuel pipe (not shown).

The fuel supplied to the fuel passage 7a is supplied to the injectors 6A, 6B, and 6C, respectively. In this embodiment, the injectors 6A, 6B, and 6C and the delivery pipe 7 constitute a fuel supply device.

As shown in FIG. 2, injectors 6A, 6B, and 6C are provided with connectors 6D, 6E, and 6F, respectively, and power sources for operating injectors 6A, 6B, and 6C are connected to connectors 6D, 6E, and 6F via wire harnesses (not shown).

As shown in Figures 2, 3, and 4, the delivery pipe 7 has a bottom wall 7A, a front wall 7B, a left side wall 7C, a right side wall 7D, a ceiling wall 7E, and a rear wall 7F.

The bottom wall 7A extends in the front-rear direction from the injector 6A to the injector 6C, and is located above the injectors 6A, 6B, and 6C.

The front wall 7B extends upward from the front end of the bottom wall 7A. The left side wall 7C connects the left end of the bottom wall 7A to the left end of the front wall 7B. The right side wall 7D connects the right end of the bottom wall 7A to the right end of the front wall 7B.

The ceiling wall 7E faces the bottom wall 7A in the vertical direction and connects the upper end of the front wall 7B, the upper end of the left side wall 7C, and the upper end of the right side wall 7D. The rear wall 7F is made of a cap member and is fitted to the rear end of the bottom wall 7A, the rear end of the ceiling wall 7E, the rear end of the left side wall 7C, and the rear end of the right side wall 7D to prevent fuel from leaking from the fuel passage 7a.

As shown in FIG. 2, a fuel inlet pipe 7G is provided on the right side wall 7D of the delivery pipe 7, and the fuel inlet pipe 7G is connected to the fuel pipe. This allows fuel to be supplied from the fuel pipe to the fuel passage 7a through the fuel inlet pipe 7G.

As shown in FIG. 4, fuel outlets 7b, 7c, and 7d are formed in bottom wall 7A, and fuel outlets 7b, 7c, and 7d are located above injectors 6A, 6B, and 6C. Fuel inlets 6a, 6b, and 6c are formed in the upper parts of injectors 6A, 6B, and 6C, and fuel outlets 7b, 7c, and 7d face fuel inlets 6a, 6b, and 6c in the vertical direction.

Cylindrical connectors 7H, 7I, and 7J are provided on the bottom wall 7A, and the connectors 7H, 7I, and 7J protrude downward from the bottom wall 7A. The upper ends of the injectors 6A, 6B, and 6C are fitted into the connectors 7H, 7I, and 7J.

The fuel supplied to the fuel passage 7a of the delivery pipe 7 is supplied from the fuel outlets 7b, 7c, and 7d through the connectors 7H, 7I, and 7J to the fuel inlets 6a, 6b, and 6c of the injectors 6A, 6B, and 6C.

Sealing members such as O-rings (not shown) are interposed between the connectors 7H, 7I, 7J and the injectors 6A, 6B, 6C, and these sealing members prevent fuel from leaking from the connectors 7H, 7I, 7J.

As shown in FIG. 3, the center portion C1 of the connector 7H in the vehicle width direction is biased to one side (the right side) from the center portion C of the delivery pipe 7 in the vehicle width direction.

As a result, the central axis C2 of the injector 6A is offset to one side (the right side) from the center C of the delivery pipe 7 in the vehicle width direction. This allows the fuel discharge port 7b to be formed in the bottom wall 7A closer to the right side wall 7D than to the left side wall 7C. The center C1 of the connector 7H in the vehicle width direction and the central axis C2 of the injector 6A are coaxial.

As shown in FIG. 4, the delivery pipe 7 is tilted backward so that the front end 7f is positioned higher than the rear end 7r. In other words, the delivery pipe 7 is tilted backward so that it is approximately parallel to the crankshaft 2S.

As shown in Figures 4 and 5, the upper rear portion of the ceiling wall 7E from the injector 6A is the top portion 7t in the vertical direction, and the portion in front of the top portion 7t is located below and in the vicinity of an imaginary horizontal plane 11 that is in contact with the top portion 7t.

Specifically, the ceiling wall 7E has a rear ceiling wall portion 7K that extends from the rear end portion 7r of the ceiling wall 7E to the top portion 7t, an inclined wall portion 7M that extends diagonally downward to the front from the top portion 7t, and a front ceiling wall portion 7N that extends from the bottom end portion 7m of the inclined wall portion 7M to the front end portion 7f of the ceiling wall 7E.

The injector 6A is installed forward of the inclined wall portion 7M and below the front ceiling wall portion 7N.

In the delivery pipe 7, the front ceiling wall portion 7N, the rear ceiling wall portion 7K, and the bottom wall 7A are installed in parallel. That is, as shown in FIG. 5, imaginary planes 12, 13 extending along the front ceiling wall portion 7N and the rear ceiling wall portion 7K extend in parallel, and the front ceiling wall portion 7N and the rear ceiling wall portion 7K have a step H with the inclined wall portion 7M sandwiched therebetween.

Next, the effects of the fuel supply device of this embodiment will be described.
The engine 1 of this embodiment has a crankshaft 2S that is tilted backward so that a front end 2f is positioned higher than a rear end 2r.

The fuel supply device of this embodiment is provided on top of the engine 1 and includes injectors 6A, 6B, and 6C that inject fuel into cylinders 2A, 2B, and 2C, respectively, and a delivery pipe 7 that has a fuel passage 7a extending in the front-rear direction and supplies fuel to the injectors 6A, 6B, and 6C.

The delivery pipe 7 has a bottom wall 7A in which fuel outlets 7b, 7c, and 7d are formed, which discharge fuel to the fuel inlets 6a, 6b, and 6c of the injectors 6A, 6B, and 6C, and a ceiling wall 7E that faces the bottom wall 7A in the vertical direction, and is tilted backward so that the front end 7f is located higher than the rear end 7r.

The upper rear portion of the injector 6A located at the forefront of the delivery pipe 7 is the top portion 7t in the vertical direction, and the portion forward of the top portion 7t is located below and in the vicinity of an imaginary horizontal plane 11 that is in contact with the top portion 7t.

As a result, compared to a delivery pipe in which the front end 7f of the delivery pipe 7 is the top in the vertical direction due to the crankshaft 2S being tilted backward, the top 7t can be positioned rearward of the front end 7f, and the front end 7f can be made lower than the top 7t.

As a result, even if the delivery pipe 7 is installed tilted backward, the vertical gap between the top part 7t of the delivery pipe 7 and the vehicle body member 10 above the top part 7t can be increased, and interference between the top part 7t and the vehicle body member 10 can be avoided.

On the other hand, air bubbles B may accumulate near the ceiling wall 7E inside the delivery pipe 7 due to air in the fuel piping flowing into the delivery pipe 7 or the temperature of the fuel in the fuel passage 7a inside the delivery pipe 7 rising and vaporizing. These air bubbles B travel along the ceiling wall 7E of the delivery pipe 7 and accumulate at the front end 7f side, which is located higher inside the delivery pipe 7.

In this embodiment, the delivery pipe 7 has the front ceiling wall portion 7N, which is located in front of the top portion 7t of the ceiling wall 7E, located below the imaginary horizontal plane 11 that contacts the top portion 7t and in the vicinity of the imaginary horizontal plane 11, so that the front ceiling wall portion 7N can be brought closer to the bottom wall 7A.

As a result, as shown in FIG. 3, the air bubbles B in the fuel passage 7a of the delivery pipe 7 can be guided to the fuel intake port 6a of the injector 6A through the fuel outlet 7b together with the fuel sucked in by the injector 6A. As a result, the air bubbles B can be quickly discharged from the fuel passage 7a to the outside of the delivery pipe 7.

In this way, the fuel supply device for the engine 1 of this embodiment improves the mountability of the delivery pipe 7 on the vehicle, and can quickly expel air bubbles B generated inside the delivery pipe 7 to the outside.

In addition, the center portion C1 of the connector 7H of the delivery pipe 7 in the vehicle width direction is offset to one side (right side) from the center portion C of the delivery pipe 7 in the vehicle width direction, so the central axis C2 of the injector 6A can be installed offset to one side (right side) from the center portion C of the delivery pipe 7 in the vehicle width direction. This allows the fuel discharge port 7b to be formed in the bottom wall 7A closer to the right side wall 7D than to the left side wall 7C.

As a result, as shown in FIG. 3, the air bubbles B that have accumulated near the top wall 7E can be guided along the right side wall 7D to the bottom wall 7A together with the fuel, and then guided to the fuel intake port 6a of the injector 6A through the fuel outlet 7b. As a result, the air bubbles B can be easily discharged from the fuel passage 7a. The arrow of the air bubbles B in FIG. 3 indicates the direction of movement of the air bubbles B.

The center portion C1 of the connector 7H of the delivery pipe 7 in the vehicle width direction may be offset toward the other side (left side) from the center portion C of the delivery pipe 7 in the vehicle width direction. In this way, the central axis C2 of the injector 6A can be installed offset toward the other side (left side) from the center portion C of the delivery pipe 7 in the vehicle width direction.

Even with this configuration, the air bubbles B that have accumulated near the ceiling wall 7E can be guided along the left side wall 7C to the bottom wall 7A together with the fuel, and then guided through the fuel outlet 7b to the fuel intake 6a of the injector 6A, making it easy to expel the air bubbles B from the fuel passage 7a.

In addition, according to the delivery pipe 7 of this embodiment, the ceiling wall 7E has a rear ceiling wall portion 7K that extends from the rear end portion 7r to the top portion 7t, and an inclined wall portion 7M that extends diagonally downward to the front side from the top portion 7t, and the injector 6A is installed forward of the inclined wall portion 7M.

As a result, as shown in FIG. 5, the air bubbles B can be easily guided along the inclined wall portion 7M to the front ceiling wall portion 7N together with the fuel sucked in by the injector 6A, and then through the fuel outlet 7b to the fuel intake port 6a of the injector 6A. As a result, the air bubbles B can be quickly discharged from the fuel passage 7a to the outside of the delivery pipe 7. The arrow of the air bubbles B in FIG. 5 indicates the movement direction of the air bubbles B.

Here, if the front ceiling wall portion 7N approaches the bottom wall 7A from the lower end portion 7m of the inclined wall portion 7M toward the front, the distance between the front ceiling wall portion 7N and the bottom wall 7A gradually decreases, and there is a risk that a space cannot be secured between the front ceiling wall portion 7N and the bottom wall 7A to supply a sufficient amount of fuel to the injector 6A.

On the other hand, if the front ceiling wall portion 7N moves away from the bottom end portion 7m of the inclined wall portion 7M toward the front and away from the bottom wall 7A, the distance between the front ceiling wall portion 7N and the bottom wall 7A gradually increases, making it difficult to suck the air bubbles B that have accumulated in the front ceiling wall portion 7N into the injector 6C from the fuel discharge port 7b, and it may not be possible to easily discharge them from the delivery pipe 7.

In contrast, in the delivery pipe 7 of this embodiment, the ceiling wall 7E has a front ceiling wall portion 7N that extends from the lower end 7m of the inclined wall portion 7M to the front end 7f of the ceiling wall 7E, and the front ceiling wall portion 7N, rear ceiling wall portion 7K, and bottom wall 7A are installed in parallel.

This prevents the space between the front ceiling wall portion 7N and the bottom wall 7A from being excessively reduced, and ensures an optimal space between the front ceiling wall portion 7N and the bottom wall 7A for supplying an appropriate amount of fuel to the injector 6A, i.e., an optimal fuel passage 7a.

In addition, the vertical distance between the front ceiling wall portion 7N and the bottom wall 7A can be set to a distance that allows air bubbles B to be easily discharged from the front ceiling wall portion 7N to the fuel discharge port 7b of the bottom wall 7A.

In this way, the delivery pipe 7 of this embodiment has the front ceiling wall portion 7N, the rear ceiling wall portion 7K, and the bottom wall 7A arranged in parallel, so that the necessary space for the fuel passage 7a that supplies fuel to the injector 6A is secured, while air bubbles B can be easily discharged from the fuel discharge port 7b to the injector 6A.

Although an embodiment of the present invention has been disclosed, it is apparent that modifications may be made by one of ordinary skill in the art without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

1...engine (internal combustion engine), 2A, 2B, 2C...cylinder, 2f...front end (front end of crankshaft), 2r...rear end (rear end of crankshaft), 2S...crankshaft, 6A...injector (fuel supply device, fuel injection valve, front fuel injection valve), 6a, 6b, 6c...fuel intake, 6B, 6C...injector (fuel injection valve), 7...delivery pipe (fuel supply device), 7A...bottom wall, 7a...fuel passage, 7b, 7c, 7d...fuel discharge port, 7E...ceiling wall, 7f...front end (front end of delivery pipe), 7K...rear ceiling wall, 7M...inclined wall, 7m...bottom end (bottom end of inclined wall), 7N...front ceiling wall, 7r...rear end (rear end of delivery pipe), 7t...top, 11...virtual horizontal plane

Claims (2)

A fuel supply device for an internal combustion engine having a plurality of cylinders arranged in a longitudinal direction of a vehicle and a crankshaft extending in the longitudinal direction of the vehicle and tilted backward so that a front end is located higher than a rear end,
a plurality of fuel injection valves provided in an upper portion of the internal combustion engine and configured to inject fuel into each of the plurality of cylinders;
a delivery pipe having a fuel passage extending in a front-rear direction of the vehicle and supplying fuel to the plurality of fuel injection valves,
the delivery pipe has a bottom wall in which a fuel discharge port for discharging fuel to a fuel inlet of the plurality of fuel injection valves is formed, and a ceiling wall facing the bottom wall in a vertical direction, and is inclined backward so that a front end of the delivery pipe is located higher than a rear end of the delivery pipe,
when a fuel injection valve located at the frontmost position in a front-to-rear direction of a vehicle among the plurality of fuel injection valves is defined as a front fuel injection valve, an upper rear portion of the front fuel injection valve is the uppermost portion in a vertical direction, and a portion of the ceiling wall forward of the uppermost portion is disposed below an imaginary horizontal plane that is in contact with the uppermost portion and in the vicinity of the imaginary horizontal plane ,
a fuel supply device for an internal combustion engine, characterized in that the ceiling wall has a rear ceiling wall portion extending from a rear end of the ceiling wall to the uppermost portion, and an inclined wall portion extending diagonally downward to the front from the uppermost portion, and the front fuel injection valve is installed forward of the inclined wall portion . The ceiling wall has a front ceiling wall portion extending from a lower end of the inclined wall portion to a front end of the ceiling wall,
2. The fuel supply device for an internal combustion engine according to claim 1, wherein the front ceiling wall portion, the rear ceiling wall portion and the bottom wall are arranged in parallel with each other.

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