JP6435996B2 - Fuel injection device - Google Patents

Description

  The present invention relates to a fuel injection device having an in-tank pump and a non-positive displacement in-line pump.

  As a fuel injection device used for a diesel engine, Patent Document 1 discloses an apparatus having a pressure accumulating container for storing fuel in a high pressure state, a fuel tank for storing fuel in a low pressure state, and a supply line connecting them. Has been. The supply line has a so-called in-line pump arranged in the supply line as a pump for introducing the fuel in the fuel tank into the supply line. The in-line pump is a positive displacement type (specifically, a trochoid type).

Japanese Patent Application Laid-Open No. 2014-202075

However, the fuel injection device described in Patent Document 1 has the following problems.
In general, the fuel injection device needs to perform scavenging by removing the air in the supply line after its assembly or after the fuel tank runs out of fuel. As in the fuel injection device described in Patent Document 1, in the case of having only an inline pump as a pump for supplying fuel into the supply line, scavenging of the supply line is performed as follows. That is, in the fuel injection device, scavenging is performed by filling the supply line with fuel from the end on the fuel tank side and pushing out air in the supply line to the outside. However, the fuel injection device has only an in-line pump as a pump for supplying fuel into the supply line. For this reason, when scavenging the supply line, it is necessary to connect a hand pump or the like to the supply line to introduce fuel.

  Further, since the low-pressure pump is a positive displacement type in which the fuel suction portion and the discharge portion are not communicated with each other, it is difficult to fill the fuel from the upstream pipe to the downstream pipe of the low-pressure pump. Therefore, in the fuel injection device, it is necessary to separately connect a bypass path for filling the supply line with fuel during scavenging in parallel with the low-pressure pump. Furthermore, even if the bypass path is connected as described above, scavenging in the in-line pump cannot be performed.

  The present invention has been made in view of such a background, and intends to provide a fuel injection device capable of reducing the number of parts for scavenging a supply line and improving the efficiency of scavenging of the supply line. It is.

One aspect of the present invention is a fuel injection device used in a diesel engine,
A pressure accumulation chamber for storing fuel in a high pressure state;
A fuel injection valve for injecting fuel stored in the pressure accumulation chamber;
A fuel tank for storing fuel in a low pressure state;
A supply line connecting the fuel tank and the pressure accumulating chamber;
A positive displacement in -tank pump disposed in the fuel tank and pumping the fuel in the fuel tank to the supply line;
A part of the supply line, a non-volumetric in-line pump that pumps fuel supplied from the in-tank pump to the pressure accumulating chamber side;
A part of the supply line, and a booster pump that pressurizes the fuel supplied from the inline pump to the high pressure state and pumps the fuel to the pressure accumulator
One end of the supply line is connected between the in-line pump and the booster pump, and a scavenging line for removing air accumulated in the supply line is provided.

  The fuel injection device includes an in-tank pump and an in-line pump. Therefore, at the time of scavenging the supply line, by stopping the driving of the inline pump and driving the in-tank pump, the supply line can be filled with fuel and the scavenging can be easily performed. Therefore, it is not necessary to connect a hand pump or the like to the supply line when scavenging the supply line. Therefore, the working efficiency of scavenging can be improved.

  The fuel injection device has a non-positive displacement inline pump. That is, in the inline pump, the fuel suction part and the discharge part communicate with each other. Therefore, when scavenging the supply line, it is easy to fill the fuel from the upstream piping to the downstream piping of the inline pump. Therefore, scavenging of the supply line can be performed via the inline pump. As a result, it is not necessary to separately connect a bypass path for scavenging in parallel with the in-line pump in the supply line, and the scavenging efficiency in the in-line pump can be improved.

  As described above, according to the present invention, it is possible to provide a fuel injection device that can reduce the number of parts for scavenging the supply line and improve the scavenging efficiency of the supply line.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. Sectional drawing which shows the structure of the in-tank pump in Embodiment 1. FIG. Sectional drawing which shows the structure of the in-line pump in Embodiment 1. FIG.

(Embodiment 1)
An embodiment of a fuel injection device will be described with reference to FIGS.
The fuel injection device 1 of this embodiment is used for a diesel engine. As shown in FIG. 1, the fuel injection device 1 includes a pressure accumulating chamber 2, a fuel injection valve 3, a fuel tank 4, a supply line 5, an in-tank pump 6, an in-line pump 51, a booster pump 52, and a scavenging line 7.

  The pressure accumulating chamber 2 stores fuel in a high pressure state. The fuel injection valve 3 injects fuel stored in the pressure accumulation chamber 2. The fuel tank 4 stores fuel in a low pressure state. The supply line 5 connects the fuel tank 4 and the pressure accumulation chamber 2. The in-tank pump 6 is arranged in the fuel tank 4 and pumps the fuel in the fuel tank 4 to the supply line 5. The in-line pump 51 constitutes a part of the supply line 5 and pumps the fuel supplied from the in-tank pump 6 to the pressure accumulating chamber 2 side. The inline pump 51 is a non-volumetric type. The booster pump 52 constitutes a part of the supply line 5, pressurizes the fuel supplied from the inline pump 51 to a high pressure state, and pumps the fuel to the pressure accumulation chamber 2. One end of the scavenging line 7 is connected between the in-line pump 51 and the booster pump 52 in the supply line 5, and the air accumulated in the supply line 5 is extracted.

  The fuel injection device 1 is a device for injecting fuel (light oil) into each cylinder of a diesel engine by a fuel injection valve 3. The fuel injected by the fuel injection valve 3 is pumped from the fuel tank 4 to the pressure accumulating chamber 2 through the supply line 5 and supplied from the pressure accumulating chamber 2 to the fuel injection valve 3.

  The fuel tank 4 is a tank for storing fuel. The pressure in the fuel tank 4 is atmospheric pressure. The fuel in the fuel tank 4 is pumped to the supply line 5 by driving the in-tank pump 6.

  The in-tank pump 6 is a positive displacement type. In this embodiment, as shown in FIG. 2, the in-tank pump 6 is a trochoid pump that is a kind of positive displacement pump. That is, the in-tank pump 6 includes an outer rotor 61 having a plurality of teeth 611 formed on the inner peripheral portion thereof, and is accommodated on the inner peripheral side of the outer rotor 61, and has a smaller number of teeth than the outer rotor 61. The inner rotor 62 formed on the outer peripheral side 621 is accommodated in the trochoid case 60. The in-tank pump 6 rotates the outer rotor 61 and the inner rotor 62 relative to each other and also with respect to the trochoid case 60. As the motor rotates, the volume of the gap formed between the teeth 611 of the outer rotor 61 and the teeth 621 of the inner rotor 62 is increased or decreased, and fuel is sucked from the suction opening 601 formed in the trochoid case 60 or discharged. The ink is discharged from the opening 602.

  As shown in FIG. 1, the fuel supplied from the fuel tank 4 into the supply line 5 by the in-tank pump 6 is pumped to the in-line pump 51 through the fuel filter 11. As the fuel passes through the fuel filter 11, the fuel is filtered.

  The in-line pump 51 is configured to pressurize the fuel supplied from the in-tank pump 6 side and pump it to the booster pump 52 side. As shown in FIG. 3, the inline pump 51 is a cascade pump that is a kind of non-volumetric pump. That is, the inline pump 51 includes an impeller 512 that has a plurality of blade portions 511 and is rotatably arranged, and a cascade case 513 that houses the impeller 512. A substantially annular fuel passage region 514 for allowing fuel to pass therethrough is formed in a region on the outer peripheral side of the impeller 512 in the cascade case 513. The cascade case 513 is formed with an inlet 515 for introducing fuel into the fuel passage region 514 and an outlet 516 for discharging fuel from the fuel passage region 514. The introduction port 515 and the discharge port 516 of the cascade case 513 communicate with each other through the fuel passage region 514. Further, a partition wall 518 is provided between the introduction port 515 and the discharge port 516 in the fuel passage region 514 so that the fuel introduced from the introduction port 515 to the fuel passage region 514 does not go again to the introduction port 515 side. Is formed.

  The inline pump 51 is configured to be driven by a crankshaft (not shown) provided in the diesel engine. In this embodiment, the rotating shaft 517 of the impeller 512 of the inline pump 51 is connected to the crankshaft and rotates in conjunction with the rotation of the crankshaft. For example, every time the crankshaft makes one revolution, the impeller 512 is driven so as to make a half revolution or one revolution. By rotating the impeller 512 of the inline pump 51, fuel is introduced from the introduction port 515 into the fuel passage region 514 in the cascade case 513, and a flow along the rotation direction of the impeller 512 is generated in the introduced fuel. Discharge from 516 to the booster pump 52 side.

  The fuel discharged from the inline pump 51 is pumped to the booster pump 52 side. At this time, the pressure of the fuel discharged from the inline pump 51 is adjusted to a predetermined pressure or less by the regulator valve 12. The regulator valve 12 causes the discharge side and the suction side of the inline pump 51 to communicate with each other when the pressure of the fuel discharged from the inline pump 51 exceeds a predetermined level.

  Further, the fuel discharged from the in-line pump 51 is pressure-fed to the booster pump 52 via the suction adjustment valve 13. The intake adjustment valve 13 adjusts the amount of fuel pumped from the in-line pump 51 to the booster pump 52. The amount of fuel pumped from the in-line pump 51 to the booster pump 52 is adjusted by opening and closing the suction adjustment valve 13. That is, the suction adjusting valve 13 can adjust the amount of fuel pumped from the in-line pump 51 to the booster pump 52 by controlling the valve opening time.

  The booster pump 52 is configured to pressurize the fuel supplied from the inline pump 51 side to a high pressure state and pump the fuel to the pressure accumulating chamber 2. The booster pump 52 is a so-called plunger pump. The booster pump 52 is provided eccentrically with respect to the rotatable cam shaft 521, the central axis of the cam shaft 521, and slidable with respect to the outer peripheral surface of the cam 522 and the cam 522 that rotates integrally with the cam shaft 521. And a plunger 523 that reciprocates in the cylinder 526 as the cam 522 rotates. The cam 522 converts the rotational motion of the cam shaft 521 into the reciprocating motion of the plunger 523. The cam 522 and the sliding portion between the cam 522 and the plunger 523 are accommodated in the cam chamber 524. A pressurizing chamber 525 whose volume is changed by the reciprocating motion of the plunger 523 is formed inside the cylinder 526.

  A suction-side check valve 527 is provided on the in-line pump 51 side of the pressurizing chamber 525 to communicate or block the pressurizing chamber 525 and the in-line pump 51. A discharge-side check valve 528 that communicates with or blocks the pressure accumulation chamber 2 is provided. When the plunger 523 moves in the direction to increase the volume of the pressurizing chamber 525, the suction side check valve 527 is opened and the discharge side check valve 528 is closed, and the fuel is pressurized via the suction side check valve 527. To be introduced. Then, when the plunger 523 stops at a position where the volume of the pressurizing chamber 525 is maximized and starts to move in a direction to reduce the volume of the pressurizing chamber 525, the suction side check valve 527 is also closed. The fuel introduced into the pressurizing chamber 525 moves in a direction in which the plunger 523 reduces the volume of the pressurizing chamber 525 in a state where both the suction side check valve 527 and the discharge side check valve 528 are closed. Pressurize by continuing. When the pressure of the fuel in the pressurizing chamber 525 becomes a certain level or higher, only the discharge side check valve 528 is opened and the fuel is pumped to the pressure accumulating chamber 2.

  The pressure accumulating chamber 2 is for storing fuel in a high pressure state. The pressure of the fuel in the pressure accumulating chamber 2 becomes the pressure when fuel is injected from the fuel injection valve 3.

Next, the scavenging line 7 will be described.
One end of the scavenging line 7 is connected between the in-line pump 51 and the suction regulating valve 13 in the supply line 5. As a result, when the supply line 5 is scavenged, the fuel can be supplied from the supply line 5 to the scavenging line 7 by keeping the suction adjustment valve 13 closed. That is, the fuel injection device 1 has an openable / closable valve that is disposed between the connection portion 53 of the supply line 5 with the scavenging line 7 and the booster pump 52. In the present embodiment, the on-off valve is the suction adjustment valve 13. During normal operation, when the intake adjustment valve 13 is open, the fuel discharged from the in-line pump 51 is sent to the pressurizing chamber 525 of the booster pump 52 and part of the fuel is also present in the scavenging line 7. Sent. When the intake adjustment valve 13 is closed, the fuel discharged from the inline pump 51 is sent to the scavenging line 7.

  The end of the scavenging line 7 opposite to the supply line 5 is arranged in the fuel tank 4. That is, the scavenging line 7 communicates the connecting portion 53 of the supply line 5 with the fuel tank 4. Thereby, in the present embodiment, the scavenging of the supply line 5 fills the fuel in the fuel tank 4 into the supply line 5, discharges the fuel from the scavenging line 7 into the fuel tank 4, and air into the fuel tank 4. This is done by extruding.

  The scavenging line 7 communicates the connecting portion 53 of the supply line 5 and the fuel tank 4 via the cam chamber 524 of the booster pump 52. That is, the drive unit (cam 522) of the booster pump 52 is disposed in a part of the scavenging line 7. Thereby, the fuel sent from the supply line 5 to the scavenging line 7 is filled in the cam chamber 524. The sliding portion between the cam 522 and the plunger 523, which is the drive portion of the booster pump 52, can be lubricated by the fuel filled in the cam chamber 524. A throttle 71 for adjusting the flow rate of the fuel sent to the scavenging line 7 is provided between the connection portion 53 and the cam chamber 524.

  The scavenging line 7 is also connected to the fuel injection valve 3 and the pressure accumulating chamber 2 via a return line 8. Thereby, the fuel leaking from the pressure accumulation chamber 2 and the fuel injection valve 3 can be returned to the fuel tank 4 through the return line 8 and the scavenging line 7. That is, the fuel returning from the pressure accumulating chamber 2 to the fuel tank 4 is fuel that leaks from the pressure accumulating chamber 2 to adjust the pressure in the pressure accumulating chamber 2 when the fuel pressure in the pressure accumulating chamber 2 becomes a predetermined pressure or higher. It is. Further, the fuel returning from the fuel injection valve 3 to the fuel tank 4 is fuel that is not injected by the fuel injection valve 3 among the fuel supplied from the pressure accumulating chamber 2 to the fuel injection valve 3.

Next, a method of scavenging for removing air from the supply line 5 in the present embodiment will be described.
The fuel injection device 1 performs scavenging in the supply line 5 via the scavenging line 7 after the assembly or after the fuel tank 4 has run out of fuel. The scavenging is performed by driving the in-tank pump 6 with the driving of the in-line pump 51 stopped and the suction adjustment valve 13 closed. By driving the in-tank pump 6, the fuel in the fuel tank 4 is filled into the supply line 5 and the scavenging line 7 from the upstream side. At this time, the fuel is also filled in the in-tank pump 6 in a state where the driving is stopped. Thereby, the air in the supply line 5 is pushed out to the fuel tank 4 through the scavenging line 7. As described above, the air in the supply line 5 can be discharged from the fuel tank 4 to the outside.

Next, the effect of this embodiment is demonstrated.
The fuel injection device 1 includes an in-tank pump 6 and an in-line pump 51. Therefore, at the time of scavenging the supply line 5, the driving of the in-line pump 51 is stopped and the in-tank pump 6 is driven, so that the supply line 5 can be filled with fuel and the scavenging can be easily performed. Therefore, it is not necessary to connect a hand pump or the like to the supply line 5 when scavenging the supply line 5. Therefore, the working efficiency of scavenging can be improved.

  The fuel injection device 1 also has a non-volumetric inline pump 51. That is, the in-line pump 51 communicates with the fuel suction part (introduction port 515) and the discharge part (discharge port 516). Therefore, when scavenging the supply line 5, it is easy to fill the fuel from the upstream piping to the downstream piping of the inline pump 51. Therefore, scavenging of the supply line 5 can be performed via the inline pump 51. As a result, it is not necessary to separately connect a bypass path for scavenging in parallel with the inline pump 51 in the supply line 5, and the scavenging efficiency in the inline pump 51 can be improved.

The in-tank pump 6 is a positive displacement type. Therefore, scavenging can be performed efficiently. In other words, the in-tank pump 6 that is driven when scavenging the supply line 5 is a positive displacement pump that can apply a relatively strong pressure to the fuel, thereby improving scavenging efficiency.
In the case of a diesel engine, the viscosity of the fuel tends to be relatively high in a low temperature state. Therefore, the fuel tank 4 also has an in-tank pump 6 in addition to the in-line pump 51. Further, by making the in-tank pump 6 positive displacement, the fuel tank 4 can be connected to the pressure accumulating chamber 2 even during normal operation. The fuel can be pumped efficiently.

  The inline pump 51 is configured to be driven by a crankshaft included in the diesel engine. Therefore, energy efficiency can be increased as compared with the case where the inline pump 51 is electrically operated.

  Further, the end of the scavenging line 7 opposite to the supply line 5 is arranged in the fuel tank 4. Therefore, the fuel that has passed through the scavenging line 7 can be easily circulated to the fuel tank 4.

  Further, the supply line 5 has an openable on-off valve (suction adjustment valve 13) disposed between the connection portion 53 of the scavenging line 7 and the booster pump 52. Therefore, when scavenging the supply line 5, the fuel can be sent from the supply line 5 to the scavenging line 7 by closing the on-off valve. Therefore, scavenging of the supply line 5 can be performed easily.

  Further, the drive unit of the booster pump 52 is disposed in a part of the scavenging line 7. Therefore, during normal operation, the fuel charged in the scavenging line 7 can be used as a lubricating oil for lubricating the drive unit of the booster pump 52.

  As described above, according to the present embodiment, it is possible to provide a fuel injection device capable of reducing the number of parts for scavenging the supply line and improving the efficiency of scavenging the supply line.

DESCRIPTION OF SYMBOLS 1 Fuel injection apparatus 2 Pressure accumulation chamber 3 Fuel injection valve 4 Fuel tank 5 Supply line 51 Inline pump 52 Booster pump 6 In tank pump 7 Scavenging line

Claims (5)

A fuel injection device (1) used for a diesel engine,
A pressure accumulation chamber (2) for storing fuel in a high pressure state;
A fuel injection valve (3) for injecting fuel stored in the pressure accumulation chamber (2);
A fuel tank (4) for storing fuel in a low pressure state;
A supply line (5) connecting the fuel tank (4) and the pressure accumulating chamber (2);
A positive displacement in -tank pump (6) disposed in the fuel tank (4) and pumping the fuel in the fuel tank (4) to the supply line (5);
A non-volumetric in-line pump (51) that constitutes a part of the supply line (5) and that pumps fuel supplied from the in-tank pump (6) to the pressure accumulating chamber (2);
A booster pump (52) that constitutes a part of the supply line (5), pressurizes the fuel supplied from the inline pump (51) to the high-pressure state, and pumps the fuel to the pressure accumulating chamber (2)
One end of the supply line (5) is connected between the in-line pump (51) and the booster pump (52), and a scavenging line (7) for removing air accumulated in the supply line (5), A fuel injection device (1) comprising: The fuel injection device (1) according to claim 1, wherein the in- line pump (51) is configured to be driven by a crankshaft included in the diesel engine . The fuel injection device (1) according to claim 1 or 2, characterized in that an end of the scavenging line (7) opposite to the supply line (5) is arranged in the fuel tank (4). 1). 2. An openable on-off valve disposed between the connection portion (53) of the supply line (5) with the scavenging line (7) and the booster pump (52) . A fuel injection device (1) given in any 1 paragraph of Claims 3. The fuel injection device (1) according to any one of claims 1 to 4, wherein a drive part of the boost pump (52) is arranged in a part of the scavenging line (7 ).

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