JP2024060362A - Automotive internal combustion engines - Google Patents

Abstract

[Problem] To lay out pipes and harnesses in an automobile internal combustion engine equipped with a high-pressure fuel pump in a state that ensures excellent safety. [Solution] A brake booster vacuum pump 12, as an example of an auxiliary device, is fixed to the left side (one side) of a head cover 3, and a high-pressure fuel pump 21 is fixed to the left-leaning portion of the upper surface of the head cover 3. The left side of the upper portion of the head cover 3 and the portion behind the high-pressure fuel pump 21 constitutes a piping and wiring required area 46 in which pipes and harnesses are intertwined. A high-pressure fuel pipe 25 to which pressurized fuel is supplied is arranged so as to not pass through the piping and wiring required area 46, but to head toward the front of the engine body 4 and then wrap around the brake booster vacuum pump 12 from below. A forward-facing protruding portion 25b of the high-pressure fuel pipe 25 is protected by a metal plate protector 34. [Selected Figure] Fig. 7

Description

This invention relates to an internal combustion engine for an automobile equipped with a high-pressure fuel pump.

In a direct injection internal combustion engine, fuel is pressurized by a high-pressure fuel pump and then injected into the cylinders. For this reason, a high-pressure fuel pipe that delivers the pressurized fuel is connected to the high-pressure fuel pump. The high-pressure fuel pipe is made of metal such as a steel pipe, and its end is connected to a high-pressure fuel delivery pipe, and a high-pressure injector is connected to a branch pipe that branches off from the high-pressure fuel delivery pipe.

An important factor in an automotive internal combustion engine is fire prevention in the event of an accident such as a collision. If a high-pressure fuel pipe breaks during an accident and high-pressure fuel sprays out, it could lead to a serious fire. Therefore, care must be taken to ensure that the high-pressure fuel pipe will not break even if an accident occurs. As an example, Patent Document 1 discloses that the high-pressure fuel pump and piping are covered from the front by an auxiliary device such as a supercharger. In Patent Document 1, the high-pressure fuel pump is located at the end of the intake side of the cylinder block.

JP 2020-45810 A

In Patent Document 1, in a front intake type internal combustion engine, the high-pressure fuel pump is fixed to the intake side of the cylinder block and is protected by a supercharger. However, if a supercharger is not provided, it is difficult to protect the high-pressure fuel pump in the event of a collision accident. Therefore, it is preferable to place the high-pressure fuel pump in a location where it is unlikely to be subjected to impact in the event of a collision accident, such as the top surface of the head cover.

When the high-pressure injector that injects high-pressure fuel into the cylinder is located at the bottom end of the cylinder head, the high-pressure fuel delivery pipe is located to the side of the bottom end of the cylinder head, so when the high-pressure fuel pump is fixed to the top surface of the head cover, the high-pressure fuel pipe extends downward. However, since the low-pressure fuel tube and harnesses that supply fuel to the high-pressure fuel pump are often located on the upper part of the head cover, there is a concern that the piping and wiring will become tangled and come into contact with the high-pressure fuel pipe, causing the harness to break or the low-pressure fuel tube to rupture.

The present invention was made against this background, and aims to achieve an appropriate layout for the high-pressure fuel pipes while fixing the high-pressure fuel pump to the top surface of the head cover.

The present invention is directed to an internal combustion engine mounted in an engine room provided at the front of an automobile body, and the internal combustion engine comprises:
"An engine body including a head cover, a high-pressure fuel pump connected to a high-pressure fuel pipe is fixed to the upper surface of the head cover, and a portion of the high-pressure fuel pipe is disposed so as to extend along one side surface of the engine body,
And, an auxiliary machine is arranged on one side of the engine body.
In this basic configuration,
"The high-pressure fuel pipe is disposed in such a manner that it exits the high-pressure fuel pump, heads downward, and then wraps around the auxiliary equipment from below."
It has the following characteristics:

The present invention can be developed in various ways. For example, in claim 2, in claim 1,
"The auxiliary machine is fixed to a boss portion protruding from one side surface of the engine body, and the auxiliary machine has a downward protruding portion protruding below the boss portion,
A portion of the high pressure fuel pipe passes through the space between the engine body and the downward protruding portion of the auxiliary machinery.
The structure is as follows.

The invention of claim 3 is the same as claim 1 or 2,
"The engine body is disposed in the engine room with the one side surface facing the vehicle width direction,
the high-pressure fuel pipe has a forward protruding portion located from the high-pressure fuel pump to a front of the engine body, and extends rearward from a lower end of the forward protruding portion along one side surface of the engine body,
A protector is fixed to the engine body or head cover, which covers the forward protruding portion of the high-pressure fuel pipe from the front.
The structure is as follows.

As an example of the development of the invention of claim 3, claim 4 states:
"The protector has a trough-shaped portion that surrounds the forward protruding portion of the high-pressure fuel pipe from the front, and when the trough-shaped portion is pushed from the front and hits the engine body or the head cover, the forward protruding portion of the high-pressure fuel pipe is maintained in a state surrounded by the trough-shaped portion."
The structure is as follows.

In the present invention, the high-pressure fuel pipe extends downward from the high-pressure fuel pump and is arranged so as to wrap around the accessories from below. This ensures a large space above the head cover where the high-pressure fuel pipe is not arranged, and the low-pressure fuel tube and various harnesses can be arranged in this space. Therefore, even with long-term use, the high-pressure fuel pipe is prevented from interfering with the low-pressure fuel tube and various harnesses, preventing damage to the low-pressure fuel tube and disconnection of the harnesses. This improves safety.

In addition, because the high-pressure fuel pipe is positioned so that it wraps around the auxiliary equipment from below, the high-pressure fuel pipe can be protected by the auxiliary equipment in the event of an accident. In other words, the auxiliary equipment can also be used as a protector for the high-pressure fuel pipe. This also improves safety.

In the configuration of claim 2, if another member moves toward one side of the engine body in the event of an accident, the other member will collide with the auxiliary equipment and will not hit the high-pressure fuel pipe, improving the protection function of the high-pressure fuel pipe and further improving safety.

When the internal combustion engine is placed horizontally in the engine compartment with rear intake, it is reasonable to pull the high-pressure fuel pipe downward from the front of the engine body and then extend it toward the rear, as in claim 3, to prevent interference with the intake manifold and low-pressure fuel tubes and harnesses.

If a portion of the high-pressure fuel pipe protrudes forward of the engine body in this way, there is a risk that the high-pressure fuel pipe may be damaged if a component located at the front of the vehicle body, such as a radiator support, hits the protruding portion of the high-pressure fuel pipe in the event of a collision. However, by providing a protector as in claim 3, damage to the high-pressure fuel pipe can be prevented. Therefore, safety in the event of an accident can be improved.

Furthermore, as a specific example of claim 3, if the protector is provided with a gutter-shaped portion that surrounds the high-pressure fuel pipe as in claim 4, the protruding portion of the high-pressure fuel pipe can be prevented from being crushed, deformed, or broken by the protector hitting the engine body or head cover while covering the protruding portion of the high-pressure fuel pipe. This can further improve safety in the event of an accident.

FIG. 2 is a partial perspective view of the embodiment as seen from the rear side. FIG. 2 is a partial front view showing the embodiment in dotted lines. FIG. 2 is a partial front view showing the embodiment in solid lines. FIG. 2 is a partial side view showing the embodiment in dotted lines. FIG. 2 is a partial side view showing the embodiment in solid lines. FIG. 2 is a partial plan view showing the embodiment in dotted lines. FIG. 2 is a partial plan view showing the embodiment in solid lines. FIG. 2 is a diagram showing a form of a protector. FIG. 11 is a partial plan view showing the operation during a collision accident.

(1) Overview of the embodiment Next, an embodiment of the present invention will be described with reference to the drawings. In the following, the terms front, rear, left and right are used to specify directions, but these directions are defined as directions seen from the driver's perspective. A front view is a direction facing the driver. The up-down direction is the axial direction of the cylinder bore, which is approximately the same as the vertical direction.

As shown in Figures 2 and 3, an internal combustion engine has a cylinder block 1, a cylinder head 2 fixed to the top surface of the cylinder block 1, and a head cover 3 fixed to the top surface of the cylinder head 2, which together form the engine body 4. The cylinder head 2 has a two-layer structure consisting of a lower head 2a and an upper head (cam carrier) 2b, and a camshaft (not shown) is rotatably held in the upper head 2b.

The internal combustion engine of this embodiment is a rear-intake (front-exhaust) type, with the crank axis elongated in the vehicle width direction (left-right direction) and the intake side facing backward in the direction of travel. The engine body has a timing chain cover and an oil pan (not shown), and the timing chain cover is fixed to the right side of the cylinder head 2 and the cylinder block 1. The transmission case is fixed to the left side of the cylinder block 1 and the oil pan.

The left side of the cylinder head 2 is the water distribution section for discharging the cooling water, and is provided with a cooling water port 5 to which hoses are connected. Also, as shown in Figures 2 and 3, a cooling water passage 6 that sends cooling water to a water pump or the like is opened at the left end of the front surface of the lower head 2a.

Reference numeral 7 in FIG. 1 denotes a surge tank that constitutes the intake manifold. Reference numeral 8 in FIG. 1 denotes a part of the intake duct, to which air is supplied from an air cleaner (not shown). The intake duct 8 is fixed to a throttle body 9. Reference numeral 10 in FIG. 1 denotes a PCV gas return hose. In this embodiment, in relation to the claims, the left side surface of the engine body 4 corresponds to one side surface.

As shown in Figures 1 to 7, a brake booster vacuum pump 12, which is an example of an auxiliary device, is fixed to the left side of the upper head 2b with bolts 13. The vacuum pump 12 is fixed to a boss portion 2c that protrudes to the left from the upper head 2b. Also, as shown in Figures 2 and 3, the vacuum pump 12 has a downward protrusion 12a that protrudes below the boss portion 2c, so that a space 32 is formed between the lower head 2a and the downward protrusion 12a.

The vacuum pump 12 is driven by an exhaust camshaft. The rotor of the vacuum pump 12 and the exhaust camshaft are concentric. For this reason, the vacuum pump 12 is disposed on the left side of the upper head 2b, toward the front. As shown in Figures 1 to 3, 6, and 7, a vacuum line 14 that draws air from the brake booster is connected to the vacuum pump 12. The vacuum line 14 is drawn backward from above the vacuum pump 12, and is connected to the brake booster disposed in front of the driver's seat in the engine room. As shown in Figures 1, 3, and 4, the middle part of the vacuum line 14 is supported by the head cover 3 and the upper head 2b via brackets 15 and 16.

The head cover 3 is made of aluminum or synthetic resin and is formed in the shape of a shallow tray that opens downward, and the flange 3a is fixed to the upper head 2b with multiple bolts 17. As shown in Figure 1, one end (starting end) of the PCV gas return hose 10 described above is connected to the head cover 3.

For example, as shown in Figures 5 and 6, a cam angle sensor 18 is fixed to the left end of the front side of the head cover 3. The detection portion of the cam angle sensor 18 is inserted inside the head cover 3 and faces a gear-shaped dog provided at the left end of the exhaust camshaft. A harness 18a is connected to the cam angle sensor 18.

1, 6 and 7, a high-pressure fuel pump 21 is fixed with bolts to a left-hand, forward portion of the upper surface of the head cover 3. The high-pressure fuel pump 21 is basically cylindrical and has a flange 22 at its lower end that is longitudinally extended from front to rear. The flange 22 is fixed with bolts to the upper surface of the head cover 3 via a spacer 23.

A low-pressure fuel tube 24 for supplying fuel from the fuel tank, a high-pressure fuel pipe 25 for discharging pressurized fuel, and a harness 26 for control are connected to the outer periphery of the high-pressure fuel pump 21. The low-pressure fuel tube 24 and the high-pressure fuel pipe 25 are connected to the high-pressure fuel pump 21 via joints 27, 28, and the harness 26 is connected to the high-pressure fuel pump 21 via a detachable connector 29. The midway point of the low-pressure fuel tube 24 is supported by the head cover 3 via a support 30.

In this case, as shown in Figures 6 and 7, the joint 27 of the low-pressure fuel tube 24 is attached to the rear and left side of the high-pressure fuel pump 21, and the high-pressure fuel pipe 25 is disposed forward and outward to the left. Furthermore, the connector 29 to which the harness 26 is connected is disposed on the outer periphery of the high-pressure fuel pump 21 in a rear and right side position.

The low-pressure fuel tube 24 extends generally rearward above the head cover 3, while the high-pressure fuel pipe 25 has an upper horizontal portion 25a that is inclined in a plan view toward the left front corner of the head cover 3, a vertically long forward protruding portion 25b that extends downward from the front end of the upper horizontal portion 25a and is positioned forward of the head cover 3 and upper head 2b, and a front-to-rear downward horizontal portion 25c that extends rearward from the bottom end of the forward protruding portion 25b along the left side of the cylinder head 2.

As shown in FIG. 2, the forward protruding portion 25b of the high-pressure fuel pipe 25 protrudes to the left outside of the head cover 3 at both the upper and lower ends in front and plan views, and the portion between the upper and lower ends bulges to the right in front view (convex to the right) so that a significant portion of the portion overlaps with the head cover 3 and the upper head 2b in front view.

As shown in FIG. 1, the rear end of the lower horizontal portion 25c that constitutes the high-pressure fuel pipe 25 is connected to one end (left end) of the high-pressure fuel delivery pipe 31. Although not shown in the figure, the high-pressure fuel delivery pipe 31 is long in the left-right direction along the rear surface of the lower head 2a, and high-pressure fuel injectors corresponding to each cylinder are connected to the high-pressure fuel delivery pipe 31. In this embodiment, the tip of the high-pressure fuel injector faces the combustion chamber from the lower end of the lower head 2a. This is therefore a horizontal injection method.

For example, as shown in Figures 2 and 3, the downward horizontal portion 25c of the high-pressure fuel pipe 25 extends rearward through the space 32 between the downward protruding portion 12a of the vacuum pump 12 and the left side surface of the cylinder head 2. Therefore, in a side view, the high-pressure fuel pipe 25 is oriented as if it were wrapped around the vacuum pump 12 from below. As can be seen from Figures 2 and 3, the downward horizontal portion 25c is supported by a bracket 33 fixed to the upper head 2b.

(3) Protector As shown in Fig. 3, for example, the forward protruding portion 25b of the high-pressure fuel pipe 25 is protected from the front by a protector 34. The protector 34 is made of a metal plate such as a steel plate or a stainless steel plate, and as shown in Fig. 8, has a gutter-shaped portion 35 that surrounds the forward protruding portion 25b of the high-pressure fuel pipe 25 from the front, and an attachment portion 36 that is integrally provided at the lower end of the gutter-shaped portion 35, and a cylindrical collar 37 is welded to the rear surface of the attachment portion 36. The attachment portion 36 is fixed to the front surface of the lower head 2a by bolts 38 via the collar 37.

As shown in FIG. 8, the gutter-shaped portion 35 of the protector 34 has left and right side plates 39, 40 that protrude rearward from the base plate, but in this embodiment, the protruding dimension of the right side plate 40 is greater than the protruding dimension of the left side plate 39 (they may be the same protruding dimension, or the protruding relationship may be reversed). The base plate of the gutter-shaped portion 35 has upper and lower longitudinal reinforcing ribs 41 that bulge rearward. The gutter-shaped portion 35 is gutter-shaped with a rearward opening in a plan view, and due to the synergistic effect of the reinforcing ribs 41, it is less likely to bend or deform in the front-to-rear direction.

For example, as shown in FIG. 3, the gutter-shaped portion 35 is inclined in front view so that the upper end is shifted to the left and the lower end is shifted to the right. This is due to the misalignment between the fixed position by the bolt 38 and the position of the forward protruding portion 25b.

As shown in FIG. 8, the mounting portion 36 of the protector 34 is bent backward from the base plate of the protector 34. This is to ensure that the gutter portion 35 has enough space to surround the forward protruding portion 25b while bringing the mounting portion 36 closer to the lower head 2a.

When an impact acts on the gutter-shaped portion 35 from the front, the load is concentrated at the connection between the gutter-shaped portion 35 and the mounting portion 36. However, in this embodiment, the mounting portion 36 is also integrally connected to the right side plate 40, which provides a high rib effect and increases resistance to impacts from the front (the gutter-shaped portion 35 is less likely to tip backwards).

As shown in FIG. 9, the collar 37 of the protector 34 is fixed to a stepped portion 41 formed on the front surface of the lower head 2a (it is also possible to fix the mounting portion 36 directly to the front surface of the lower head 2a (or upper head 2b) without using the collar 37). As shown in FIG. 2, the stepped portion 41 has a tapped hole 41a.

For example, as shown in Figures 3 and 8(A), the mounting portion 36 is formed with a positioning groove 42 that opens to the right side, and a rearward-facing positioning piece 43 is bent and formed in the lower portion between the positioning groove 42. On the other hand, as shown in Figures 2 and 3 (also see Figure 9), a positioning boss portion 44 into which the positioning groove 42 fits is formed on the right side of the stepped portion 41 on the front surface of the lower head 2a. The positioning piece 43 is designed to abut against the underside of the positioning boss portion 44 from below.

Since the protector 34 is fastened by a single bolt 38, when the bolt 38 is tightened, the protector 34 tries to rotate to the right when viewed from the front. However, because the positioning groove 42 fits into the positioning boss 44 and the positioning piece 43 hits the positioning boss 44 from below, the position of the protector 34 is maintained when the bolt 38 is tightened. Therefore, the protector 34 can be accurately fixed in a specified position with only a single bolt 38.

For example, as shown in FIG. 3, the lower part of the right-hand portion of the protector 34 is cut out to avoid interference with the downward horizontal portion 25c of the high-pressure fuel pipe 25 (the cutout portion is indicated by the reference symbol 45). As shown in FIG. 8(C) and (D), the right side plate 40 of the gutter-shaped portion 35 of the protector 34 has first to third steps 40a, 40b, 40c that are successively lower from the bottom, and an inclined portion 40d that is continuous with the upper end of the third step 40c, and the steps 40a, 40b, 40c are set so as to abut or come close to the front surface of the upper head 2b. The inclined portion 40d protrudes above the head cover 3 in a front view.

(4) Summary This embodiment is configured as described above. Since the high-pressure fuel pipe 25 faces diagonally forward from the high-pressure fuel pump 21, there is a piping and wiring required area 46, in which the low-pressure fuel tube 24 and harnesses must be arranged, behind the front end of the high-pressure fuel pump 21 in the upper left part of the head cover 3, as shown by dotted lines in FIG. 7 . If the high-pressure fuel pump 21 is present in the piping and wiring required area 46, and since the high-pressure fuel pump 21 is made of a hard metal, when the low-pressure fuel tube 24 or harnesses come into contact with the high-pressure fuel pump 21, vibration may accelerate wear, resulting in a risk of rupture or disconnection.

In contrast, in this embodiment, the high-pressure fuel pipe 25 extends forward from the high-pressure fuel pump 21 and is not present in the required piping wiring area 46, so the low-pressure fuel tube 24 and harnesses will not come into contact with and be damaged by the high-pressure fuel pipe 25. This improves safety.

On the other hand, because components such as the radiator and the radiator support that supports it are located in front of the internal combustion engine, if the high-pressure fuel pipe 25 protrudes into the area in front of the head cover 3, there is a risk that in the event of a collision, for example, the radiator support may move backward and collide with the high-pressure fuel pipe 25, causing damage or deformation of the high-pressure fuel pipe 25. However, in this embodiment, the forward protruding portion 25b of the high-pressure fuel pipe 25 is covered with a protector 34, so damage to the high-pressure fuel pipe 25 in the event of an accident can be prevented or significantly reduced.

Now, since the lower end of the protector 34 is fixed to the lower head 2a by the bolts 38, if the protector 34 is pushed backward by a member such as the radiator support in the event of a collision, the protector 34 will tend to fall backward and rotate. Therefore, if the protector 34 were simply a flat plate, the forward protruding portion 25b of the high-pressure fuel pipe 25 would be strongly pressed against the head cover 3 or cylinder head 2 by the protector 34, and there would be a risk of it being damaged or deformed.

In contrast, in this embodiment, the forward protruding portion 25b of the high-pressure fuel pipe 25 is surrounded by the gutter-shaped portion 35 of the protector 34. Even if the gutter-shaped portion 35 falls backward and rotates, hitting the front surface of the head cover 3 or the front surface of the cylinder head 2, the gutter-shaped portion 35 keeps the forward protruding portion 25b surrounded, so the forward protruding portion 25b will not be damaged or deformed. This maintains a high level of safety.

To further explain this embodiment, since the right side plate 40 of the gutter-shaped portion 35 abuts or is close to the front surface of the cylinder head 2, in the event of a collision, the left side plate 39 deforms backward and stops deforming when it abuts the upper head 2b. However, as shown in FIG. 9, since the clearance (E1+E2) between the forward protrusion 25b and the high-pressure fuel pump 21 is greater than the amount of backward movement L of the left side plate 39, the forward protrusion 25b is not crushed by the high-pressure fuel pump 21, and therefore a high level of safety can be ensured. Even if the forward protrusion 25b is pressed by the protector 34 and elastically deforms, there is no impact on safety.

Furthermore, in this embodiment, the downward horizontal portion 25c of the high-pressure fuel pump 21 faces rearward through the space 32 between the left side surface of the cylinder head 2 and the downward protruding portion 12a of the vacuum pump 12. However, since the vacuum pump 12 has a sturdy structure given its function, even if an external force acts from the left side in the event of an accident, the downward horizontal portion 25c of the high-pressure fuel pump 21 can be protected by the vacuum pump 12. This further improves safety.

Although the embodiment of the present invention has been described above, the present invention can be embodied in various other ways. For example, the protector may be fastened with multiple bolts. For example, an electric water pump may be used as an accessory to protect part of the high-pressure fuel pipe. The present invention can also be applied to a horizontally mounted, front-intake type internal combustion engine, or a vertically mounted internal combustion engine whose crank axis is long in the front-to-rear direction of the vehicle body.

The present invention can be embodied in an automotive internal combustion engine equipped with a high-pressure fuel pump. Therefore, it can be used industrially.

2 Cylinder head 2a Lower head 2b Upper head 2c Boss portion 3 Head cover 4 Engine body 12 Brake booster vacuum pump as an example of an auxiliary 12a Downward protruding portion 21 High pressure fuel pump 24 Low pressure fuel tube 25 High pressure fuel pipe 25a Upper lateral portion 25b Forward protruding portion 25c Lower lateral portion 32 Space 34 Protector 35 Gutter-shaped portion 36 Mounting portion 37 Collar (spacer)
38 Bolt 39, 40 Side plate 46 Area where piping and wiring are required

Claims (4)

An internal combustion engine mounted in an engine compartment provided at the front of a vehicle body,
an engine body including a head cover, a high-pressure fuel pump connected to a high-pressure fuel pipe being fixed to an upper surface of the head cover, and a portion of the high-pressure fuel pipe being disposed so as to extend along one side surface of the engine body,
In addition, in a configuration in which an auxiliary machine is disposed on one side surface of the engine body,
The high-pressure fuel pipe is disposed in such a position that it exits the high-pressure fuel pump, extends downward, and then wraps around the auxiliary equipment from below.
Automotive internal combustion engine. The auxiliary machine is fixed to a boss portion protruding from one side surface of the engine body, and the auxiliary machine has a downward protruding portion protruding below the boss portion,
a part of the high-pressure fuel pipe passes through a space between the engine body and a downward protruding portion of the auxiliary machinery;
2. An internal combustion engine for an automobile according to claim 1. The engine body is disposed in the engine room with the one side surface facing the vehicle width direction,
the high-pressure fuel pipe has a forward protruding portion located from the high-pressure fuel pump to a front of the engine body, and extends rearward from a lower end of the forward protruding portion along one side surface of the engine body,
A protector is fixed to the engine body or the head cover to cover the forward protruding portion of the high-pressure fuel pipe from the front.
3. An internal combustion engine for an automobile according to claim 1 or 2. the protector has a gutter-shaped portion surrounding the forward protruding portion of the high-pressure fuel pipe from the front, and when the gutter-shaped portion is pushed from the front and hits the engine body or the head cover, the state in which the forward protruding portion of the high-pressure fuel pipe is surrounded by the gutter-shaped portion is maintained.
4. An internal combustion engine for an automobile according to claim 3.

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