JP2002089407A - Fuel system for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lighten the weight of a fuel system using a common rail, reduce the cost, and improve the external appearance quality. SOLUTION: The other end of each of a plurality of injection nozzles 6 having one end inserted into a cylinder head 4 for every cylinder is covered with a cylinder head cover 5. The single common rail 3 provided parallel to a crankshaft is connected to a fuel injection pump 2 via a single first fuel pipe 7 and connected to respective injection nozzles 6 via a plurality of second fuel pipes 8. The common rail 3 is stored in the cylinder head cover 5, the tip of a first short pipe 10 projected to the common rail 3 is faced to a first insertion part 11 formed in the side wall 4a of the cylinder head 4 and the first fuel pipe 7 is connected to the first short pipe 10 through the first insertion part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for a diesel engine using a common rail for accumulating and holding fuel supplied to each injection nozzle of the engine.

[0002]

2. Description of the Related Art Conventionally, in this type of fuel supply apparatus, FIG.
As shown in FIG. 6, a single fuel injection pump 102 and a single common rail 103 are provided outside the engine 101. The single common rail 103 is provided in parallel with the crankshaft on the fuel injection pump 102 provided below the intake manifold 109. One end of each of the plurality of injection nozzles 106 is inserted into the cylinder head 104 for each cylinder, and the other end is covered by a cylinder head cover 105. The common rail 103 is connected to the fuel injection pump 102 via a single first fuel pipe 107, and is connected to a plurality of injection nozzles 106 via a plurality of second fuel pipes 108, respectively. Common rail 103 is used for each injection nozzle 1
The fuel supplied to 06 is accumulated and held. Reference numeral 115 in FIG. 16 is a pressure sensor that detects the fuel pressure in the common rail 103.

[0003]

However, in the conventional fuel supply system for a diesel engine, as shown in FIG. 16, it is necessary to lay out a plurality of second fuel pipes 108 outside the engine 101 while avoiding interference. Therefore, the second fuel pipe 108 has a long and complicated shape, and there is a problem that the weight of the fuel supply device is increased and the production cost is increased. An object of the present invention is to provide a fuel supply device for a diesel engine, which can reduce the weight and cost and improve the appearance quality. Another object of the present invention is to make it possible to use an inexpensive pressure sensor with low oil resistance by preventing oil splashes in the cylinder head cover from being applied to the pressure sensor that detects the fuel pressure in the common rail. An object of the present invention is to provide a fuel supply device for a diesel engine.

[0004]

The invention according to claim 1 is
As shown in FIGS. 1 and 3, a plurality of injection nozzles 6 each having one end inserted into a cylinder head 4 for each cylinder and the other end covered by a cylinder head cover 5, and a fuel injection pump 2 provided in parallel with the crankshaft. And a single common rail 3 connected to a plurality of injection nozzles 6 via a plurality of second fuel pipes 8 respectively. It is an improvement of the device. The characteristic configuration is that the common rail 3 is housed in the cylinder head cover 5, and the tip of the first short pipe 10 protruding from the common rail 3 faces the first insertion portion 11 formed on the side wall 4 a of the cylinder head 4. The first fuel pipe 7 is connected to the first short pipe 10 through the first insertion portion 11.

In the fuel supply system for a diesel engine according to the first aspect, the length of the second fuel pipe 8 connecting each of the injection nozzles 6 provided for each cylinder and the common rail 3 can be reduced, and It is only necessary to arrange a single first fuel pipe 7 outside the cylinder head cover 5 instead of a plurality of second fuel pipes 8.

A second aspect of the present invention is the invention according to the first aspect, further comprising an external thread formed at the tip of the first short pipe 10 as shown in FIGS. A nut 7a that can be screwed into the male screw is provided at an end of the first fuel pipe 7. By screwing the nut 7a into a male screw with the nut 7a loosely inserted into the first insertion portion 11, the first fuel pipe 7 It is connected to the short pipe 10, and the gap between the nut 7 a and the first insertion portion 11 is closed by the first seal member 12. In the fuel supply device for a diesel engine according to the second aspect, since the gap is closed by the first seal member 12, the cylinder head cover 5 may be used.
It is possible to reliably prevent the oil splash inside from leaking out of the cover 5 through the gap.

The invention according to claim 3 is the invention according to claim 1, further comprising a pressure sensor 15 for detecting the fuel pressure in the common rail 3, as shown in FIGS. The end of the second short pipe 13 protruding from the second insertion portion 1 formed on the side wall 4a of the cylinder head 4
The pressure sensor 15 is mounted on the distal end of the second short pipe 13 so as to protrude outward through the fourth short pipe 4. In the fuel supply device for a diesel engine according to the third aspect, since the pressure sensor 15 is located outside the cylinder head cover 5, the oil droplets in the cylinder head cover 5 hardly hit the pressure sensor 15.

The invention according to claim 4 is the invention according to claim 3, wherein the gap between the second short tube 13 and the second insertion portion 14 is a second seal, as shown in FIGS. It is characterized by being closed by the member 16. In the fuel supply device for a diesel engine according to the fourth aspect, since the gap is closed by the second seal member 16, oil droplets in the cylinder head cover 5 are applied to the pressure sensor 15 through the gap. Since there is nothing at all, an inexpensive pressure sensor 15 having low oil resistance, which has been conventionally used, can be used as it is.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a first embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 3, the fuel supply device of the diesel engine 1 has one end (lower end) parallel to a plurality of injection nozzles 6 inserted into the cylinder head 4 for each cylinder and a crankshaft (not shown). And a single common rail 3 attached to the upper surface of the cylinder head 4. The upper surface of the cylinder head 4 is covered by a cylinder head cover 5 (FIG. 1).
As a result, the other ends (upper ends) of the plurality of injection nozzles 6 projecting from the upper surface of the cylinder head 4 are also covered by the cylinder head cover 5, and the common rail 3 is also accommodated in the cylinder head cover 5. The common rail 3 is connected to the fuel injection pump 2 via a single first fuel pipe 7, and is connected to a plurality of injection nozzles 6 via a plurality of second fuel pipes 8. Further, the fuel injection pump 2 is provided outside the engine 1.

A first short pipe 10 and a second short pipe 13 project from the common rail 3 (FIG. 3). The tip of the first short pipe 10 faces a circular through hole 11 (first insertion portion) formed in the side wall 4 a of the cylinder head 4, and the tip of the first fuel pipe 7 is provided at the tip of the first short pipe 10. Are connected via a nut 7a. A male screw (not shown) is formed at the tip of the first short pipe 10, and a female screw (not shown) that can be screwed to the male screw is formed at the nut 7a. Nut 7a is hexagonal part 7b
And a cylindrical portion 7c loosely inserted into the through hole 11. The nut 7a is rotatably fitted to the end of the first fuel pipe 7 in advance, and the female screw of the nut 7a is inserted into the cylindrical portion 7c through the through hole 1.
The first short pipe 10 is screwed into the male screw of the first short pipe 10 while being loosely inserted into the first short pipe 1. Further, the gap between the cylindrical portion 7c of the nut 7a and the through hole 11 is closed by the first seal member 12 (FIGS. 1 and 3). The fuel delivered from the fuel injection pump 2 is configured to be stored in the common rail 3 housed in the cylinder head cover 5 and then supplied to each of the injection nozzles 6.

On the other hand, as shown in FIGS. 2 and 4 to 6, the second short tube 13 has a notch 14 (second insertion portion) formed in a substantially U-shape on the side wall 4a of the cylinder head 4. A pressure sensor 15 for detecting the fuel pressure in the common rail 3 is attached to the tip of the cylinder head 4. The gap between the outer peripheral surface of the second short pipe 13 and the inner peripheral surface of the notch 14 is closed by the second seal member 16. The pressure sensor 15 detects the fuel pressure in the common rail 3, and a control unit (not shown) is configured to optimally control the fuel pressure of the common rail 3 based on the detection output of the pressure sensor 15. .

As shown in detail in FIGS. 4 to 6, the second seal member 16 has a first hole 1 that can be fitted into the second short pipe 13.
A rubber body 17 having 7 a and a plate 18 having a second hole 18 a that can be fitted into the second short pipe 13 are provided. The rubber body 17 is loosely inserted into the substantially U-shaped notch 14, and the plate 18 is attached to the surface of the side wall 4 a of the cylinder head 4 by a bolt (not shown) so as to abut the outer surface of the rubber body 17. The second short pipe 1 is provided on the inner peripheral surface of the rubber body 17.
An inner lip 17b that is in pressure contact with the outer peripheral surface of the cylinder 3 is provided, and a back lip 18b that is in pressure contact with the surface of the side wall 4a of the cylinder head 4 is provided on the rear surface of the plate 18.

In the fuel supply device configured as described above,
The length of a plurality of second fuel pipes 8 connecting each injection nozzle 6 provided for each cylinder and the common rail 3 can be reduced as compared with the conventional art, and a plurality of second fuel pipes 8 are provided outside the cylinder head cover 5. Instead of pipe 8,
Since only a single first fuel pipe 7 is arranged, the cover 5
The number of fuel pipes arranged on the outside of the fuel cell can be reduced as compared with the related art. As a result, the fuel supply device can be reduced in weight and cost, and the appearance quality around the engine 1 can be improved.

Since the pressure sensor 15 is attached to the outside of the cylinder head 4 and the gap between the second short pipe 13 and the notch 14 is closed by the second seal member 16, the oil droplets in the cylinder head cover 5 will The pressure sensor 15 does not fall through the gap, that is, the sealing property of the cylinder head cover 5 is ensured by the second seal member 16, and oil can be prevented from flowing out from the cylinder head cover 5. Can be reliably protected. As a result, the conventionally used pressure sensor 15 with low oil resistance can be used as it is.

Further, since the gap between the first short pipe 10 and the through hole 11 is formed relatively large, it is possible to increase the tolerance of the mounting position of the first short pipe 10 with respect to the through hole 11. Since the gap between the second short pipe 13 and the notch 14 is also relatively large, it is possible to increase the tolerance of the mounting position of the second short pipe 13 with respect to the notch 14.

FIGS. 7 to 9 show a second embodiment of the present invention. 7 to 9, the same reference numerals as those in FIGS. 4 to 6 indicate the same parts. In this embodiment, a substantially semicircular notch 2
A substantially arc-shaped protruding line 24a is formed on the inner peripheral surface of the inner peripheral surface 4 (second insertion portion) so as to extend in the circumferential direction thereof. And a substantially semicircular rubber body 27 having the same. On the outer peripheral surface of the rubber body 27, a substantially arc-shaped concave ridge 27b that can be fitted to the convex ridge 24a is formed. The rubber body 27 is compressed and fixed by a cylinder head cover (not shown). In addition, rubber body 2
7 has an inner lip 27c protruding from the inner peripheral surface of the second short tube 13 in pressure contact with the outer peripheral surface of the second short tube 13.

In the fuel supply device configured as described above,
Since the plate of the first embodiment is not required, the number of parts and the number of assembling steps of the second seal member 26 can be reduced. Operations and effects other than those described above are the same as those of the second embodiment of the first embodiment.
Since the operation and effect of the seal member are substantially the same, repeated description will be omitted.

FIGS. 10 to 12 show a third embodiment of the present invention. 10 to 12, the same reference numerals as those in FIGS. 4 to 6 indicate the same parts. In this embodiment, the second seal member has a first hole 37a that can be fitted into the second short pipe 13, and has an outer shape that can be loosely inserted into the substantially semicircular notch 34 (second insertion portion). A rubber body 37, a plate 38 having a second hole 38 a that can be fitted into the rubber body 37 and configured to be inserted into the notch 34, an outer peripheral surface of the plate 38 and an inner circumference of the notch 34 And a liquid gasket 39 interposed therebetween. A pair of flanges 38b, 38b project from the rear surface of the plate 38, and bolts 35, 35 are screwed into the upper surface of the cylinder head 4 through the flanges 38b, 38b, whereby the plate 38 is fixed to the cylinder head 4. You. Plate 3
A sealing groove 38c is formed on the outer peripheral surface of 8, and the liquid gasket 39 is disposed in the sealing groove 38c.
Thereby, the gap between the outer peripheral surface of the plate 38 and the inner peripheral surface of the notch 34 is closed. The inner peripheral surface of the rubber body 37 has an inner lip 37b pressed against the outer peripheral surface of the second short pipe 13.
An outer lip 37 c is provided on the outer peripheral surface of the rubber body 37 so as to press against the inner peripheral surface of the notch 34.

In the fuel supply device configured as described above,
Since the bolts 35, 35 and the flanges 38b, 38b are covered by the cylinder head cover 5, the bolts 35, 35
35 and the flanges 38b, 38b are not visible from the outside of the cover 5, and the appearance quality of the second seal member 36 is higher than that of the second seal member of the first embodiment. The functions and effects other than those described above are substantially the same as the functions and effects of the second seal member of the first embodiment, and thus the description thereof will not be repeated.

FIGS. 13 to 15 show a fourth embodiment of the present invention. 13 to 15, the same reference numerals as those in FIGS. 4 to 6 indicate the same parts. In this embodiment, the outer shape in which the second seal member 46 has the first hole 47a that can be fitted into the second short pipe 13 and can be loosely inserted into the substantially U-shaped notch 44 (second insertion portion). A plate 48 having a second hole 48a that can be fitted into the rubber body 47, a liquid gasket 49 interposed between the plate 48 and a mounting surface of the plate 48 to the cylinder head 4. Is provided.
The plate 48 has a pair of knock pins 45a, 45a (FIG. 1) on the surface of the side wall 4a of the cylinder head 4.
5), the pair of bolts 45 are positioned.
b, 45b. A sealing groove 48b is formed on the back surface of the plate 48.
The liquid gasket 49 is arranged at 8b. Thereby, the gap between the back surface of the plate 48 and the front surface of the cylinder head 4 is closed. An inner lip 47b is provided on the inner peripheral surface of the rubber body 47 so as to press against the outer peripheral surface of the second short pipe 13, and an outer lip 47c is provided on the outer peripheral surface of the rubber body 47 so as to press against the inner peripheral surface of the plate 48. Is protruded.

Next, a procedure for positioning the plate 48 with high accuracy using the pair of knock pins 45a will be described. First, a plate 48 is attached to the side wall 4a of the cylinder head 4.
The upper surface of the plate 48 and the upper surface of the side wall 4a are simultaneously processed in a state in which the knock pins 45a, 45a are temporarily assembled.
Is formed from the plate 48 to the cylinder head 4. Next, plate 4
8 is removed and the rubber body 47 is fitted into the second short pipe 13, and then the dowel pins 45a, 48c are inserted into the pin holes 48c, 48c.
Type 45a. Further, bolts 45b, 45b (FIGS. 14 and 15) are screwed into the side wall 4a via the plate 48.

In the fuel supply device configured as described above,
Since the step between the upper surface of the side wall 4a and the upper surface of the plate 48 becomes substantially zero, the upper surface of the plate 48 can be used as a tightening surface for a cylinder head cover (not shown). The functions and effects other than those described above are substantially the same as the functions and effects of the second seal member of the first embodiment, and thus the description thereof will not be repeated.

As shown in the first to fourth embodiments, a substantially U-shaped or substantially semicircular notch is provided in the side wall of the cylinder head so that the tip of the second short pipe is formed in the cylinder head. In this case, the common rail may be attached to the upper surface of the cylinder head in a state where the second seal member is attached to the second short pipe in advance. This allows the second seal member to be assembled at the same time as the common rail, eliminating the need to separately assemble the common rail and the second seal member to the cylinder head, and assembling the common rail and the second seal member. Workability can be improved. Further, in the first to fourth embodiments, the notch is formed only in the side wall of the cylinder head as the second insertion portion, but the notch is formed in both the side wall of the cylinder head and the side wall of the cylinder head cover as the second insertion portion. A notch may be formed, or a through hole may be formed only in the cylinder head. If notches are formed in both the side wall of the cylinder head and the side wall of the cylinder head cover, the size of the notch formed in the side wall of the cylinder head can be reduced. Further, the first seal member described in the first embodiment may have the same structure as the second seal member described in the first to fourth embodiments. In this case, the same operation and effect as those described in each embodiment can be obtained, and the workability of assembling the common rail can be further improved. Further, the first insertion portion is not a through hole formed in the side wall of the cylinder head, but a notch formed only in the side wall of the cylinder head, or a notch formed in both the side wall of the cylinder head and the side wall of the cylinder head cover. Good.

[0024]

As described above, according to the present invention, the common rail is housed in the cylinder head cover so as to be parallel to the crankshaft, and the tip of the first short pipe protruding from the common rail is provided on the cylinder head. Since the single first fuel pipe is connected to the first short pipe through the first insertion portion facing the first insertion portion formed on the side wall, each injection nozzle provided for each cylinder is connected to the common rail. The length of the plurality of second fuel pipes can be reduced. In addition, since only a single first fuel pipe is disposed outside the cylinder head cover, the number of fuel pipes disposed on the cylinder head side can be reduced as compared with the related art. As a result, the weight and cost of the fuel supply device can be reduced, and the appearance quality can be improved.

Further, by closing the gap between the nut and the first insertion portion with the first seal member, it is possible to reliably prevent oil splashes in the cylinder head cover from leaking out of the cover through the gap. Further, a tip of a second short pipe protruding from the common rail projects outward through a second insertion portion formed in a side wall of the cylinder head, and a pressure sensor for detecting fuel pressure in the common rail is provided on the second short pipe. If attached to the tip, oil splash in the cylinder head cover hardly hits the pressure sensor through the gap. Further, if the gap between the second short pipe and the second insertion portion is closed by the second seal member, oil splash in the cylinder head cover does not fall on the pressure sensor at all through the gap. An inexpensive pressure sensor having low oil resistance can be used as it is.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line AA of FIG. 3, showing a fuel supply device for a diesel engine according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line BB of FIG. 3;

FIG. 3 is a perspective view of a main part of the fuel supply device including a common rail.

FIG. 4 is an enlarged sectional view of a portion C in FIG. 2;

FIG. 5 is a sectional view taken along line DD of FIG. 6;

FIG. 6 is a view as seen from an arrow E in FIG. 4;

FIG. 7 is an enlarged sectional view showing a second embodiment of the present invention and corresponding to FIG. 4;

FIG. 8 is a sectional view taken along line FF of FIG. 9;

FIG. 9 is a view taken in the direction of the arrow G in FIG. 7;

FIG. 10 is an enlarged sectional view showing a third embodiment of the present invention and corresponding to FIG. 4;

FIG. 11 is a sectional view taken along line HH of FIG. 12;

FIG. 12 is a view taken in the direction of the arrow I in FIG. 10;

FIG. 13 is an enlarged sectional view corresponding to FIG. 4, showing a fourth embodiment of the present invention.

FIG. 14 is a sectional view taken along line JJ of FIG. 15;

FIG. 15 is a view as seen from the arrow K in FIG. 13;

FIG. 16 is a sectional view showing a conventional example and corresponding to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diesel engine 2 Fuel injection pump 3 Common rail 4 Cylinder head 4a Side wall 5 Cylinder head cover 6 Injection nozzle 7 First fuel pipe 7a Nut 8 Second fuel pipe 10 First short pipe 11 Through hole (first insertion part) 12 First seal Member 13 Second short pipe 14, 24, 34, 44 Notch (second insertion portion) 15 Pressure sensor 16, 26, 36, 46 Second seal member 17, 27, 37, 47 Rubber body 17a, 27a, 37a, 47a first hole 18, 38, 48 plate 18a, 38a, 48a second hole 24a convex ridge 27b concave ridge 39, 49 liquid gasket

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02F 11/00 F02F 11/00 J F02M 39/00 F02M 39/00 Z (72) Inventor Kuki Torusaka Tokyo 3-1, 1-1 Hinodai, Hino-shi, Hino Motor Co., Ltd. (72) Inventor Hiroshi Horiuchi 3-1-1, Hinodai, Hino-shi, Tokyo F-term in Hino Motor Co., Ltd. 3G024 AA07 BA00 BA15 BA21 DA02 FA08 FA13 FA14 HA14 3G066 AA07 AB02 AC09 AD05 AD12 BA00 BA61 BA63 CB01 CB03 CB12 CD04 CD10 CD17 CD25

Claims (4)

[Claims] 1. A plurality of injection nozzles (6), one end of which is inserted into a cylinder head (4) for each cylinder and the other end of which is covered by a cylinder head cover (5), and a fuel injection pump provided in parallel with a crankshaft. (2) a single common rail connected via a single first fuel pipe (7) and connected to each of the plurality of injection nozzles (6) via a plurality of second fuel pipes (8); (3) wherein the common rail (3) is housed in the cylinder head cover (5), and the first short pipe (10) protruding from the common rail (3) is provided. A first end is formed on a side wall (4a) of the cylinder head (4).
The first fuel pipe (7) faces the insertion portion (11), and the first fuel pipe (7)
A fuel supply device for a diesel engine, wherein the fuel supply device is connected through an insertion portion (11). 2. A male screw is formed at the tip of the first short pipe (10), and a nut (7a) that can be screwed to the male screw is provided at an end of the first fuel pipe (7). ) Is the first insertion part
The first fuel pipe (7) is connected to the first short pipe (10) by screwing the nut (7a) to the male screw in a state of being loosely inserted in (11), and the nut (7a) 2. The fuel supply device for a diesel engine according to claim 1, wherein a gap between the first insertion portion and the first insertion portion is closed by a first seal member. 3. A pressure sensor (15) for detecting a fuel pressure in the common rail (3), wherein a tip of a second short pipe (13) protruding from the common rail (3) is connected to a cylinder head (4). 2. The pressure sensor according to claim 1, wherein the pressure sensor protrudes outward through a second insertion portion formed on a side wall of the second short tube. 3. Fuel supply system for diesel engines. 4. A second short pipe (13) and a second insertion portion (14, 24, 34, 4).
4. The fuel supply device for a diesel engine according to claim 3, wherein a gap between the fuel supply device and the fuel supply device is closed by a second seal member (16, 26, 36, 46).