JP3094915B2 - Fuel supply system for V-type engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device applied to a V-type engine, and more particularly, to a pressure-accumulation fuel supply device.

[0002]

2. Description of the Related Art In a pressure accumulating type fuel supply device, fuel sucked up by a feed pump is pressurized by a high pressure generating pump and introduced into a common rail having a pressure accumulating chamber therein. When applied to an in-line engine, the common rail is formed in a rail shape extending in the cylinder arrangement direction, and a bracket or the like is provided on an intake manifold near a fuel injection valve provided in each cylinder connected via a fuel pipe. Mounted through. The common rail is provided with a pressure sensor and a pressure regulating valve for sensing the pressure in the accumulator, and the pressure regulating valve keeps the indoor pressure constant and uses an output signal from the pressure sensor as a trigger signal for control. In addition, the fuel injection valve is controlled by a control means in a fuel injection timing and an injection amount.

[0003]

When the pressure-accumulation type fuel supply device having such a configuration is simply applied to a V-type engine, rail-shaped common rails are individually arranged for the left and right cylinders. When the common rails are individually arranged, a plurality of pressure sensors and the like are required, and the pressure control of the common rails is individually performed, or the control is complicated, and the load on the control system is increased. Also, a plurality of brackets and the like are required, which is disadvantageous in terms of the number of parts and weight. If the mounting rigidity of the common rail is weak, the common rail may vibrate and a load may be applied to a fuel pipe connecting the common rail and the fuel injection valve.
Further, in order to secure the strength, the thickness of the bracket is increased or the number of brackets is increased, so that the mounting portion of the common rail becomes bulky and the weight of the engine increases.

[0004] In a V-type engine, ignition may occur at irregular intervals between cylinders provided in a cylinder block constituting one bank depending on the order of ignition. When a multi-action cam having a plurality of cams having different shapes is used, there is also a problem that the fuel injection and the pumping cannot be synchronized in all cylinders. That is, while the fuel is pumped from the pump at equal pitches by the multi-action cam to the common rails, the fuel flows out at irregular intervals from the common rails. When continuous ignition occurs between the cylinders of the cylinder block, the fluctuation of the fuel supply pressure to each fuel injection valve is large, and the variation of the injection pressure between the cylinders is increased.

[0005]

According to the present invention, in order to provide a fuel supply system for a V-type engine, which is lightweight, compact and has high reliability and controllability, the fuel supply system is formed in cylinder blocks arranged in a V-shaped bank. A common rail for supplying high-pressure fuel to the fuel injection valves arranged in the selected cylinder is made common to the left and right cylinder blocks, and this common rail is formed in a substantially trapezoidal cross section and arranged at the central root of the bank, and the bottom portion thereof Was mounted directly on the base of the engine, and the fuel outlets for each cylinder were radially arranged along the banks on the inclined portions on both sides. When the common rail is provided common to the left and right cylinder blocks, and is attached to the engine base at the center root located between the banks by bolts, brackets and the like become unnecessary and are arranged in the extra space of the V-type engine And the center of gravity for attachment is lowered. Therefore, it is possible to maintain the mounting rigidity of the common rail while reducing the number of parts and reducing the size, space, and weight. If the common rail has a substantially trapezoidal cross section and the bottom side is the mounting side, the mounting property and the sitting of the common rail are improved.

A fuel supply pump is disposed adjacent to a common rail having a substantially trapezoidal cross section in the cylinder arrangement direction so that variations in fuel injection characteristics can be suppressed, and high-pressure fuel from the fuel supply pump is supplied to the upper side of the common rail. A fuel inlet is provided. As described above, when the fuel supply pump is connected to the common rail, the fuel supplied from the fuel supply pump and the fuel supply to the fuel injectors of each cylinder are performed on the common common rail. Pressure fluctuations are small, and variations in injection pressure between cylinders are reduced. If the fuel supply pump is disposed close to the common rail, the pump is located between the banks, so that the pump can be easily attached and space can be saved. When the fuel inlet is provided at the upper side of the common rail, the piping from the pump to the common rail is shortened, and the piping connection work can be easily performed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel supply device according to the present invention
A common rail for accumulating high-pressure fuel to be supplied to the fuel injection valve is formed and arranged in a substantially trapezoidal cross section at a central base located between the banked cylinder blocks of the V-type engine, and a bottom portion of the common rail is an engine base. And a fuel outlet for each cylinder of the V-type engine is provided on both sides of the common rail. Generally, in the case of a V-type engine, the number of fuel pipes from the common rail to the fuel injection valve is larger than that of the fuel pipe from the fuel supply pump to the common rail. Becomes longer. Therefore, it is preferable that the fuel outlets are provided on the inclined portions on both sides of the common rail and arranged radially along the banks in consideration of piping management and space efficiency.

A fuel supply pump for supplying high-pressure fuel to the common rail is disposed adjacent to a common rail cylinder arrangement direction fixed between banks of the V-type engine, and an upper side of the common rail is provided with a fuel supply pump from the fuel supply pump. A fuel inlet through which high-pressure fuel flows is provided. Since the fuel supply pump corresponding to the common rail can be formed to have a shorter overall length than the row type pump, it can be disposed between the banks.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The V-type engine 1 shown in FIGS. 1 and 2 is a four-cycle eight-cylinder engine. Each of the left and right cylinder blocks 2 and 3 is made of special cast iron and has a bank angle of 90 ° by being inclined (banked) by 45 ° about the crankshaft 4. Cylinder # 1 and cylinder # provided in cylinder block 2
The cylinder # 5, the cylinder # 7, and the cylinder # 2, the cylinder # 4, the cylinder # 6, and the cylinder # 8 provided in the cylinder block 3 are arranged in the direction in which the crankshaft 4 extends. Aluminum intake manifolds 6, 7 are mounted on the inner upper bank surfaces 2a, 3a of the cylinder heads 2H, 3H mounted on the upper portions of the cylinder blocks 2, 3, respectively. Above each cylinder # 1 to # 8, a fuel injection valve 12 with a built-in solenoid valve for controlling fuel injection is provided on the cylinder head 2 respectively.
H, 3H. Each fuel injection valve 12 is placed under the control of a control means (not shown), and the opening and closing of a built-in electromagnetic valve is controlled by a well-known program for controlling fuel injection timing and injection amount stored in the control means. It has become.

A common rail 8 and a fuel supply pump 9 are adjacent to each other in the cylinder arrangement direction indicated by a double-headed arrow a in the space between the lower inner bank surfaces 2b and 3b of the cylinder blocks 2 and 3 which is the central root of the bank. Are located. The upper surface 5A of the crankcase has a screw hole 10 as shown in FIG.
A plurality of bosses 10 and 11 formed with a and 11a are integrally formed in parallel with each other along the cylinder blocks 2 and 3 in the crankshaft direction which is the same direction as the cylinder arrangement direction.

The common rail 8 accumulates high-pressure fuel supplied to each fuel injection valve 12 at a constant pressure.
As shown in FIG.
5B. These fuel pipes 15A, 15
B is clamped at an appropriate position by clips C fixed to a plurality of brackets B provided on the intake manifolds 6 and 7 and the cylinder blocks 2 and 3, and is restricted from free movement. As shown in FIG. 5, the common rail 8 has a substantially trapezoidal cross section, and has a pressure accumulation chamber 80 for accumulating high-pressure fuel therein. Perforated flanges 13 and 14 are formed below four corners of the common rail 8 so as to be continuous with the flat bottom portion 8a. The common rail 8 is shown in FIG.
As shown in FIG. 5, bolts 16 and 17 are inserted through the perforated flanges 13 and 14 from above and screwed into the screw holes 10 a and 11 a of the bosses 10 and 11, so that the crankcase 5
(Only one side is shown in FIG. 3), that is, the common rail 8 is fixed to the upper surface 5A of the crankcase 5 on the flat bottom side 8a side, so that the bracket as in the prior art is unnecessary. In addition, since the mounting position is lower than when mounted on the intake manifold, the center of gravity is lowered.

On both inclined surfaces 8b and 8c of the common rail 8, a plurality of fuel outlets 18,
19 are arranged side by side in the cylinder arrangement direction (the direction of the double arrow a), and the inner bank surfaces 2c, 3 of the cylinder blocks 2, 3 are arranged.
It extends radially along c. Fuel outlet 18,1
Reference numeral 9 denotes a high-pressure joint having one end 18a, 19a communicating with the pressure accumulating chamber 80 as shown in FIGS. 4 and 5. The protruding other ends 18b, 19b are connected to a fuel pipe via a high-pressure seal member (not shown). 15A and 15B are fitted into the ends.

On the flat upper side 8d of the common rail 8, there are provided fuel inlets 22, 23 into which high-pressure fuel supplied from the fuel supply pump 9 via fuel pipes 20, 21 flows. The fuel inlets 22 and 23 communicate with the accumulator 80, respectively, and the fuel pipes 20 and 21 are fitted therein. As shown in FIG. 6, a pressure regulating valve 24 having one end 24a communicating with the pressure accumulating chamber 80 is mounted on the upper side 8d. The pressure regulating valve 24 is a mechanical one that opens when the pressure reaches a set pressure. As shown in FIGS. 3 and 4, a pressure sensor 25 for detecting the pressure of the accumulator 80 is provided on the front end face 8 e of the common rail 8. The pressure sensor 25 is connected to a control device (not shown) and outputs a signal corresponding to the pressure information.

The fuel supply pump 9 is a well-known high-pressure fuel pump which pressurizes fuel supplied from a fuel tank (not shown) by a feed pump to a high pressure with a plunger 28 as shown in FIG. . This fuel supply pump 9 is provided with two pressurizing portions 9A and 9B as shown in FIGS.
A is fastened to bosses 10 and 11 provided in A. Pressurizing section 9
A is connected to the fuel inlet 22 via the fuel pipe 20, and the pressurizing section 9 B is connected to the fuel inlet 2 via the fuel pipe 21.
Connect to 3.

As shown in FIG. 7, the pressing portions 9A and 9B
Camshaft 2 connected to crankshaft 4 via connecting means (not shown) and driven to rotate at half the crankshaft rotation
Each time the plunger 28 provided inside is slid by the multi-action cam 27 above the fuel, the fuel is pressurized and fed to the common rail 3 (FIG. 7 shows one schematic configuration). . Here, the cam 27 is provided in correspondence with the injection timing of each cylinder. The ignition sequence of the engine in this embodiment is # 1, # 2, # 7,
The ignition is performed in # 3, # 4, # 5, # 6, and # 8, and continuous ignition is performed between cylinder # 7 and cylinder # 3 in cylinder block 2 and cylinders # 6 and # 8 in cylinder block 3 and one bank. Are irregularly spaced within.

In the fuel supply device having such a configuration, the common rail 8 and the fuel supply pump 9 can be attached and detached from above the bank, so that workability at the time of attachment and detachment is improved. Common rail 8 is directly bolted to crankcase 5
When the common rail 8 is provided in common with the cylinder blocks 2 and 3, sufficient mounting rigidity can be maintained and the center of gravity of the mounting can be lowered, so that vibration resistance is excellent. Further, since it is not necessary to provide a bracket or the like for attaching the common rail, it is advantageous for reducing the number of parts and for reducing the size and weight of the V-type engine 1. Fuel outlet 1
Since 8, 19 are arranged radially along the bank surfaces 2c, 3c, piping management and space efficiency are improved. Since only one pressure sensor 25 is required, the number of components can be reduced and control can be performed using the signal of one pressure sensor 25, and the control system does not need to be complicated.

According to this fuel supply system, the engine is cranked and the camshaft 2 is
When the rotary 6 is driven, the plunger 28 is driven by the multi-action cam 27 shown in FIG. At this time,
Since low-pressure fuel is supplied to the fuel supply pump 9 by a feed pump (not shown), the low-pressure fuel is supplied to the plunger 2.
The fuel is pressurized at 8 and supplied from the fuel inlets 22 and 23 of the common rail 8 into the accumulator 80 via the fuel pipes 20 and 21. When the predetermined fuel injection timing comes,
The high-pressure fuel stored at a constant fuel pressure by opening and closing the fuel control valve 12 is supplied from the fuel outlets 18 and 19 to the fuel pipe 15.
The fuel is supplied to the fuel control valve 12 via A and 15B and is sequentially injected into each cylinder according to the ignition timing. That is,
All the high-pressure fuel from the fuel supply pump 9 is supplied into the accumulator 80 of one common rail 8,
Is supplied from the accumulator 80 of the common rail 8 at a constant pressure, so that fuel is supplied to all cylinders and fuel is supplied from the fuel supply pump 9 corresponding to the cylinders. The fuel injection and the fuel supply corresponding to the cylinder can be synchronized.

As a result, even if unequally-spaced ignition occurs between cylinder # 7 and cylinder # 3 in cylinder block 2 or between cylinder # 6 and cylinder # 8 in cylinder block 3, the same as in the prior art. As compared with the case where a common rail is provided for each of the cylinder blocks 2 and 3, the pressure reduction of the common rail 8 is reduced, and
Fluctuations in the fuel supply pressure to the cylinders are small, and variations in the injection pressure between the cylinders can be minimized.

[0019]

According to the first aspect of the present invention, the mounting strength of the common rail for supplying the accumulated fuel to the fuel injection valves provided in each cylinder of the V-type engine is improved, and the bracket, the pressure sensor, and the like are improved. Therefore, even if the common rail is shared by the left and right cylinder blocks, the load on the control system can be reduced while suppressing the vibration. Therefore, the quietness, which is an advantage of the V-type engine, can be ensured, and the load on the fuel pipe connecting the common rail and the fuel injection valve can be reduced, so that the reliability of the device can be improved. Can be achieved.

According to the second aspect of the present invention, between banks,
That is, the fuel supply pump is arranged in the cylinder arrangement direction with respect to the common rail arranged in the space between the cylinder blocks on both sides, and a fuel inlet for flowing high-pressure fuel from the fuel supply pump is provided at the upper side of the common rail. As a result, the fuel pipe can be shortened, and the fuel pipe can be attached from above the engine, thereby improving workability. In addition, even if continuous ignition occurs in one cylinder block, the fuel pressure to the fuel injectors is supplied from the common common rail, reducing fluctuations in fuel pressure and reducing variations in injection pressure between cylinders. As a result, the fuel injection characteristics are stabilized.

[Brief description of the drawings]

FIG. 1 is a front view illustrating a schematic configuration of a fuel supply device for a V-type engine according to an embodiment of the present invention.

FIG. 2 is a plan view illustrating a schematic configuration of a fuel supply device for a V-type engine according to an embodiment of the present invention.

FIG. 3 is an enlarged side view showing a process of attaching the common rail to the engine base.

FIG. 4 is an enlarged plan view showing a configuration of a common rail.

FIG. 5 is a sectional view taken along the line B-B of FIG. 4 showing the configuration of the fuel outlet.

FIG. 6 is a cross-sectional view taken along the line AA of FIG. 4 illustrating the configuration of the pressure regulating valve.

FIG. 7 is an enlarged view showing a schematic configuration of a cam section of the fuel supply pump.

[Explanation of symbols]

Reference Signs List 1 V-type engine 2, 3 Cylinder 2b, 3b Central root 5 Engine base (crankcase) 8 Common rail 8a Bottom part 8b, 8c Side inclined part 8d Upper part 9 Fuel supply pump 12 Fuel injection valve 18, 19 Fuel outlet 22, 23 Fuel inlet # 1 to # 8 Cylinder

Claims (2)

(57) [Claims] 1. A V-type engine having a plurality of cylinders on both sides of a cylinder block having a V-shaped bank, and a cross-section for accumulating high-pressure fuel to be supplied to a fuel injection valve at a central root of the bank. A common rail having a substantially trapezoidal shape is arranged, and the bottom portion of the common rail having a substantially trapezoidal cross section is directly attached to the base of the V-type engine. A fuel supply device for a V-type engine, wherein an outlet is provided, and the fuel outlet is radially arranged along the bank. 2. A fuel supply pump is arranged adjacent to the common rail having a substantially trapezoidal cross section in the direction in which the cylinders are arranged, and a high pressure from the fuel supply pump is provided on an upper side of the common rail having a substantially trapezoidal cross section. 2. The fuel supply device for a V-type engine according to claim 1, further comprising a fuel inflow port through which fuel flows.