JP2010031675A - Fuel addition device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To early raise the temperature of fuel sucked in and supplied to a fuel addition valve by a fuel pump for fuel addition. <P>SOLUTION: A fuel addition device 30 is provided as an annex to a fuel supply device 23 of a construction for supplying fuel in a fuel tank 12 to an engine 10 and returning excess return fuel into the fuel tank 12. The fuel addition device includes the fuel addition valve 32 adding fuel to an exhaust pipe 25 of the engine 10, the fuel pump 34 for fuel addition supplying the fuel in the fuel tank 12 to the fuel addition valve 32, and a fuel retention container 16 provided in the fuel tank 12. The fuel addition device is constructed to store the fuel to be supplied to the engine 10 and the fuel to be supplied to the fuel addition valve 32 in the fuel retention container 16 and return the return fuel into the fuel retention container 16. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel addition apparatus.

It is known to purify NOx in exhaust gas by adding fuel from a fuel addition valve to a NOx catalyst provided in an exhaust passage of an internal combustion engine, so-called engine (see, for example, Patent Document 1).
A conventional example of this type of fuel addition apparatus will be described. FIG. 10 is a schematic configuration diagram showing an engine fuel supply device and a fuel addition device.

  As shown in FIG. 10, the fuel addition device 100 supplies the fuel in the fuel tank 102 to the engine 106 via the feed fuel pipe 104 and supplies the return fuel that has become redundant via the return fuel pipe 108. The fuel supply device 110 is configured to return to the inside. The fuel addition device 100 includes a fuel addition valve 112, a fuel addition fuel pump 114, and a pressure regulating valve 116. The fuel addition valve 112 adds or injects fuel to the exhaust pipe 118 of the engine 106. The fuel addition fuel pump 114 supplies the fuel in the fuel tank 102 to the fuel addition valve 112. The pressure regulating valve 116 regulates the fuel supplied to the fuel addition valve 112 by the fuel addition fuel pump 114 and discharges surplus fuel that has become excessive.

JP 2008-38818 A

  In the fuel addition device 100 (see FIG. 10), although the return fuel heated by the heat of the engine 106 is returned into the fuel tank 102, the return fuel is mixed with the total amount of fuel in the fuel tank 102. As a result, the temperature of the fuel is averaged. For this reason, there is a problem that the temperature of the fuel sucked by the fuel addition fuel pump 114 and supplied to the fuel addition valve 112 at the start of the engine 106 (particularly at the low temperature start) is difficult to be raised. Since this hinders the atomization of the added fuel of the fuel addition valve 112 at the time of low temperature start and the early return of performance of the fuel pump 114 for fuel addition, etc., improvement thereof is desired.

  In addition, although the fuel addition apparatus of the said patent document 1 describes the fuel pump of the fuel supply apparatus which supplies the fuel in a fuel tank to the fuel injection valve which injects a fuel in the cylinder of an engine, it is to a fuel addition valve Since a dedicated fuel pump for adding fuel to be supplied is not provided, the configuration is different from that of the present invention. That is, the fuel addition device of the present invention is proposed for a device including a dedicated fuel addition fuel pump for supplying the fuel in the fuel tank to the fuel addition valve.

  The problem to be solved by the present invention is to provide a fuel addition device capable of raising the temperature of the fuel sucked by the fuel addition fuel pump and supplied to the fuel addition valve at an early stage.

The above-mentioned problems can be solved by a fuel addition device having the gist of the configuration described in the claims.
That is, according to the fuel addition device described in claim 1, the fuel supplied to the engine and the fuel supplied to the fuel addition valve are stored in the fuel holding container of the fuel tank. It is configured to return the fuel inside. Thereby, the return fuel heated by the heat of the engine is returned to the fuel holding container of the fuel tank, and the fuel in the fuel holding container is supplied to the fuel addition valve by the fuel addition fuel pump. For this reason, the fuel in the fuel holding container having a capacity smaller than the tank capacity of the fuel tank and the return fuel are mixed, so that the fuel supplied from the fuel holding container to the fuel addition valve by the fuel addition fuel pump is reduced. The temperature can be raised early. This is effective for atomizing the fuel added to the fuel addition valve at the time of low-temperature starting, speeding up the performance return of the fuel pump for fuel addition, and the like.

  According to the fuel addition device described in claim 2 of the claims, the return fuel is sucked by the fuel pump for fuel addition. Thus, the return fuel can be directly sucked and supplied to the fuel addition valve by the fuel addition fuel pump.

  According to the fuel addition device described in claim 3 of the claims, the surplus fuel discharged from the pressure regulating valve for regulating the fuel supplied to the fuel addition valve by the fuel addition fuel pump is stored in the fuel holding container. It is set as the structure returned to (1). Thereby, the fall of the temperature of the fuel in a fuel holding | maintenance container and the fall of fuel remaining amount can be prevented or reduced.

  According to the fuel addition device described in claim 4, the jet for transferring the fuel outside the fuel holding container into the holding container by using the flow of the fuel returned into the fuel holding container. It is equipped with a pump. Therefore, by driving the jet pump using the flow of fuel returned into the fuel holding container, the fuel outside the fuel holding container can be transferred into the holding container. Further, the fuel returned to the fuel holding container is at a higher temperature than the fuel outside the fuel holding container due to the heat of the engine and the frictional heat caused by the flow. For this reason, by using the fuel returned into the fuel holding container as the drive source of the jet pump, the performance return of the jet pump can be accelerated.

  Further, according to the fuel addition device described in claim 5 of the claims, the pressure regulating valve causes the pressure of the fuel supplied from the fuel pump for fuel addition to the fuel addition valve to be higher than the steady fuel pressure and the steady fuel pressure. The pressure can be adjusted in two stages with high fuel pressure. Therefore, the pressure of the fuel supplied from the fuel addition fuel pump to the fuel addition valve is normally adjusted to a steady fuel pressure by the pressure adjustment valve, and adjusted to a high fuel pressure as necessary. Deposits adhering to the injection end portion of the fuel addition valve can be blown off by the injected fuel and removed.

  According to the fuel addition device described in claim 6, the fuel tank includes a main tank chamber provided with a fuel holding container, and a sub tank chamber partitioned from the main tank chamber. A transfer jet pump for transferring the fuel in the auxiliary tank chamber into the fuel holding container by using the flow of the fuel returned into the fuel holding container is provided. Therefore, the fuel in the sub tank chamber can be transferred into the fuel holding container by driving the jet pump using the flow of fuel returned into the fuel holding container.

  Further, according to the fuel addition device described in claim 7 of the claims, the return fuel is sucked by the fuel pump for fuel addition. Thereby, the temperature of the fuel supplied to the fuel addition valve can be raised at an early stage by directly sucking the return fuel heated by the heat of the engine by the fuel addition fuel pump. This is effective for atomizing the fuel added to the fuel addition valve at the time of low-temperature starting, and speeding up the performance recovery of the fuel pump for fuel addition.

  According to the fuel addition device described in claim 8 of the claims, the fuel tank includes a main tank chamber in which the return fuel is returned, and a sub tank chamber partitioned from the main tank chamber, A transfer jet pump is provided for transferring the fuel in the auxiliary tank chamber into the fuel holding container by using the flow of fuel returned to the tank chamber. Therefore, the fuel in the sub tank chamber of the fuel tank can be transferred into the fuel tank by driving the jet pump using the flow of fuel returned into the fuel tank.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[Example 1]
A first embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram showing an engine fuel supply device and a fuel addition device. The engine in the present embodiment is a multi-cylinder (for example, four-cylinder) diesel engine. Although not shown, the engine includes a fuel injection valve (also referred to as an injector) that injects fuel directly into each cylinder. The fuel injection valve is connected to a common rail (pressure accumulation chamber) that accumulates fuel to a predetermined pressure. The common rail is connected to a high-pressure fuel pump that operates using the rotational torque of the crankshaft of the engine as a drive source.

  As shown in FIG. 1, the engine 10 includes a fuel tank 12 that stores fuel. The fuel tank 12 is of a so-called saddle type, and the lower portion of the tank chamber is partitioned into a main tank chamber 13 and a sub tank chamber 14 by a convex portion 12b that protrudes in a mountain shape of the bottom plate portion 12a. A cup-shaped fuel holding container (also referred to as a reservoir cup, a sub tank, or the like) 16 having an open top surface is provided at the bottom of the main tank chamber 13.

  The fuel stored in the fuel holding container 16 is connected to a high-pressure fuel pump (not shown) on the engine 10 side via a feed fuel pipe 18. Therefore, the fuel in the fuel holding container 16 is supplied to the fuel injection valve through the feed fuel pipe 18 and the common rail (not shown) by the operation of the high pressure fuel pump on the engine 10 side, and the fuel injection valve is opened to open the engine. It is injected into 10 cylinders. The surplus return fuel supplied to the engine 10 (also referred to as “return fuel”) is returned to the fuel holding container 16 via the return fuel pipe 20.

  A filter 21 for filtering fuel is provided at the suction port of the feed fuel pipe 18. The fuel supply device 23 is constituted by the fuel injection valve, the common rail, the fuel pump, the feed fuel pipe 18, the return fuel pipe 20, and the like on the engine 10 side. That is, the fuel supply device 23 supplies the fuel in the fuel tank 12 (specifically, the fuel holding container 16) to the engine 10 and returns the surplus return fuel into the fuel tank 12 (specifically, the fuel holding container 16). It has a configuration.

  An exhaust pipe 25 that forms an exhaust passage is connected to the engine 10. An occlusion reduction type NOx catalyst (hereinafter referred to as “catalyst”, not shown) is provided in the middle of the exhaust pipe 25. The catalyst has a function of storing NOx in the exhaust when the oxygen concentration of the exhaust is high, and reducing the stored NOx when the oxygen concentration of the exhaust is low and a reducing agent is present. Further, in the middle of the exhaust pipe 25, there may be provided a DPF (diesel particulate filter) for filtering and removing PM (particulate matter) in exhaust gas from the diesel engine in addition to the catalyst. The fuel addition device 30 (described later) is also used in a regeneration device that regenerates the DPF by adding fuel when removing PM from the DPF and burning and purifying the PM (soot, etc.). Is. Hereinafter, devices for purifying exhaust gas such as a catalyst and / or DPF are collectively referred to as “exhaust gas purification device”.

The fuel supply device 23 is provided with a fuel addition device 30 for supplying a reducing agent to the exhaust gas purification device. The fuel addition device 30 includes a fuel addition valve 32, a fuel addition fuel pump 34, an added fuel supply pipe 36, a pressure regulating valve (also referred to as a pressure regulator) 38, and the like.
The fuel addition valve 32 is a so-called electromagnetic fuel injection valve, and injects, that is, adds fuel (light oil) as a reducing agent into a passage portion upstream of the exhaust gas purification device in the exhaust pipe 25.
The fuel addition fuel pump 34 is disposed in the fuel holding container 16. FIG. 2 is a cross-sectional view showing a fuel pump for fuel addition.

  As shown in FIG. 2, the fuel addition fuel pump 34 includes, for example, an electric motor unit 40 including an electric motor unit 40 and an impeller pump unit 41 provided at the lower end of the motor unit 40. It is a tank type fuel pump. The pump unit 41 sucks and boosts the fuel in the fuel holding container 16 (see FIG. 1) and discharges it into the motor unit 40 when the impeller 43 in the pump housing 42 is rotated by driving the motor unit 40. To do. A C-shaped pump passage 44 formed along the outer periphery of the impeller 43 is formed in the pump housing 42. Further, a fuel suction port 45 that communicates with the start end of the pump passage 44 and sucks fuel is provided on the lower surface side of the pump housing 42. A suction filter 46 that filters fuel is connected to the fuel suction port 45. In addition, the pump part 41 of the fuel pump 34 for fuel addition may be a positive displacement pump such as a trochoid pump or a vane pump in addition to the impeller pump.

  On the upper surface side of the pump housing 42, an outlet 48 that communicates with the start end of the pump passage 44 and discharges fuel into the motor housing 47 of the motor unit 40 is provided. Further, on the upper surface side of the motor housing 47, a fuel discharge port 49 for discharging the fuel that has flowed through the motor housing 47 is provided. The added fuel supply pipe 36 is connected to the fuel discharge port 49 (see FIG. 1). Therefore, the fuel discharged from the fuel addition fuel pump 34 is supplied to the fuel addition valve 32 through the added fuel supply pipe 36, and the fuel addition valve 32 is opened to enter the exhaust pipe 25. Addition or injection is made. Further, a vapor jet 50 is provided on the lower surface side of the pump housing 42 for discharging pressurized fuel during pressure increase, that is, vapor fuel including vapor (bubbles generated when the fuel is vaporized) from the pump passage 44 to the outside. (See FIG. 2).

As shown in FIG. 1, the fuel inlet 45 of the fuel addition fuel pump 34 and the outlet of the return fuel pipe 20 are arranged in an adjacent positional relationship. Therefore, the return fuel discharged from the outlet of the return fuel pipe 20 is easily drawn from the fuel inlet 45 of the fuel addition fuel pump 34.
The pressure regulating valve 38 adjusts the fuel pressure supplied to the fuel addition valve 32 by the fuel addition fuel pump 34, that is, the so-called fuel pressure. FIG. 3 is a cross-sectional view showing the pressure regulating valve.

  As shown in FIG. 3, the pressure regulating valve 38 includes, for example, a casing 52, a diaphragm 53, a valve body 54, a valve spring 55, and the like. The casing 52 includes an upper case portion 52a having a lower surface opening shape, and a lower case portion 52b having an upper surface opening shape joined to the lower surface side of the upper case portion 52a. An air opening 56 is provided in the upper wall portion of the upper case portion 52a. The lower case portion 52b includes a fuel introduction pipe 57 provided on the side wall portion and a fuel discharge pipe 58 provided on the bottom wall portion. A supply fuel introduction pipe 59 branched from the added fuel supply pipe 36 communicates with the fuel introduction pipe 57 (see FIG. 1). Therefore, the fuel pressure of the fuel flowing through the added fuel supply pipe 36 acts in the lower case portion 52b.

The diaphragm 53 is sandwiched between the case portions 52 a and 52 b of the casing 52, and the casing 52 is partitioned into an upper back pressure chamber 60 and a lower pressure regulating chamber 62. The diaphragm 53 is formed of a rubber-like elastic material and has flexibility.
The valve body 54 is provided at the center of the diaphragm 53 and opens and closes with the upper end surface of the fuel discharge pipe 58 as a valve seat by the bending deformation of the diaphragm 53.
The valve spring 55 is interposed between the opposed surfaces of the upper case portion 52a and the valve body 54, and always urges the valve body 54 in the closing direction.

  Thus, when the force that presses the diaphragm 53 in the pressure regulating chamber 62 of the pressure regulating valve 38, that is, the fuel pressure, is lower than the force that presses the diaphragm 53 in the back pressure chamber 60, that is, the elastic force of the valve spring 55. The valve body 54 is closed by the elastic force of the valve spring 55. Further, when the fuel pressure in the pressure adjusting chamber 62 becomes higher than the elastic force of the valve spring 55, the valve body 54 is opened against the elastic force of the valve spring 55. As a result, the fuel in the pressure regulating chamber 62 is discharged through the fuel discharge pipe 58, and the fuel pressure in the pressure regulating chamber 62 is lowered until it reaches a set value. When the fuel pressure in the pressure regulating chamber 62 reaches a set value, the valve body 54 is closed by the elastic force of the valve spring 55. Excess fuel discharged from the fuel discharge pipe 58 of the pressure regulating valve 38 is returned to the fuel holding container 16.

  As shown in FIG. 1, the fuel adding device 30 uses the flow of excess fuel returned from the fuel discharge pipe 58 (see FIG. 3) of the pressure regulating valve 38 into the fuel holding vessel 16. 16 includes two jet pumps 63 and 65 for transferring fuel outside the storage container. One of the jet pumps 63 is a so-called pumping jet pump 63 for pumping the fuel in the main tank chamber 13 outside the fuel holding container 16 and for transferring the fuel into the holding container 16. The other jet pump 65 is a transfer jet pump 65 because it transfers the fuel in the auxiliary tank chamber 14 into the fuel holding container 16. FIG. 4 is a cross-sectional view showing the jet pump. Since both jet pumps 63 and 65 have substantially the same configuration, only the pumping jet pump 63 will be described, and the description of the transfer jet pump 65 will be omitted.

  As shown in FIG. 4, the pumping jet pump 63 has an inner cylinder 67 and an outer cylinder 68 having a double cylindrical structure. While driving fuel serving as a driving source is supplied into the inner cylinder 67, pumping (transferred) fuel can be introduced between the inner cylinder 67 and the outer cylinder 68. Therefore, when the driving fuel is injected through the inner cylinder 67, the pumped (transferred) fuel is sucked into the outer cylinder 68 and transferred together with the fuel injected from the inner cylinder 67.

  As shown in FIG. 1, a fuel discharge pipe 58 (see FIG. 3) of the pressure regulating valve 38 is connected to the pumping jet pump 63 (specifically, the inner cylinder 67 (see FIG. 4)) via an excess fuel supply pipe 70. It is communicated. On the other hand, the fuel in the main tank chamber 13 can be introduced between the inner cylinder 67 and the outer cylinder 68 as the pumped (transferred) fuel outside the fuel holding container 16. Therefore, when surplus fuel discharged from the pressure regulating valve 38 is injected into the fuel holding container 16 from the pumping jet pump 63, the fuel in the main tank chamber 13 is sucked into the transfer jet pump 65, and the pumping pump The fuel is injected into the fuel holding container 16 together with the fuel injected from the pump 63.

  The transfer jet pump 65 (specifically, the inner cylinder 67 (see FIG. 4)) communicates with the surplus fuel supply pipe 70 via a surplus fuel branch pipe 72. On the other hand, a transfer fuel pipe 74 is connected between the inner cylinder 67 and the outer cylinder 68 for transferring the fuel in the auxiliary tank chamber 14 as pumping (transferring) fuel. Therefore, when the fuel discharged from the pressure regulating valve 38 is injected into the fuel holding container 16 from the transfer jet pump 65, the fuel in the sub tank chamber 14 is transferred into the transfer jet pump 65 via the transfer fuel pipe 74. And is transferred into the fuel holding container 16 together with the fuel injected from the transfer jet pump 65. A filter 75 for filtering fuel is provided at the suction port of the transfer fuel pipe 74.

  In the fuel addition device 30, when the fuel addition fuel pump 34 is operated, the fuel in the fuel holding container 16 is sucked into the fuel addition fuel pump 34 through the suction filter 46. The fuel sucked into the fuel pump 34 for fuel addition is pressurized and supplied to the fuel addition valve 32 from the fuel discharge port 49 via the addition fuel supply pipe 36. When the fuel addition valve 32 is opened, the exhaust pipe is opened. 25 is injected into. The so-called fuel pressure supplied to the fuel addition valve 32 by the fuel addition fuel pump 34 is regulated to a predetermined pressure by the pressure regulating valve 38. Excess fuel surplused by the pressure regulating valve 38 is supplied to the pumping jet pump 63 and the transfer jet pump 65, respectively. As surplus fuel supplied to the pumping jet pump 63 is injected into the fuel holding container 16, the fuel in the main tank chamber 13 is transferred into the fuel holding container 16 outside the fuel holding container 16 of the fuel tank 12. The Further, as the surplus fuel supplied to the transfer jet pump 65 is injected into the fuel holding container 16, the fuel in the sub tank chamber 14 of the fuel tank 12 passes through the transfer fuel pipe 74 to the fuel holding container 16. Transported in.

  According to the fuel addition device 30 described above, the fuel supplied to the engine 10 and the fuel supplied to the fuel addition valve 32 are stored in the fuel holding container 16 of the fuel tank 12 and returned to the fuel holding container 16 to return the fuel. It is a configuration. Thus, the return fuel heated by the heat of the engine 10 is returned to the fuel holding container 16 of the fuel tank 12, and the fuel in the fuel holding container 16 is supplied to the fuel addition valve 32 by the fuel addition fuel pump 34. The For this reason, the fuel in the fuel holding container 16 having a capacity smaller than the tank capacity of the fuel tank 12 and the return fuel are mixed, so that the fuel addition fuel pump 34 supplies the fuel addition valve 32 from the fuel holding container 16. The temperature of the supplied fuel can be raised at an early stage. This is effective for atomizing the fuel added to the fuel addition valve 32 at the time of low-temperature start, speeding up the performance recovery of the fuel pump 34 for fuel addition, and the like. Further, the atomization of the added fuel of the fuel addition valve 32 promotes the combustion of particulate matter such as soot in the exhaust (referred to as “PM”) and easily generates a reducing atmosphere of the exhaust purification device (not shown). can do.

  Further, the surplus fuel discharged from the pressure regulating valve 38 that regulates the fuel supplied to the fuel addition valve 32 by the fuel addition fuel pump 34 is returned to the fuel holding container 16. Thereby, the fall of the temperature of the fuel in the fuel holding | maintenance container 16 and the fall of the remaining amount of fuel can be prevented or reduced.

  Further, a pump 6 for pumping and a jet pump 65 for transferring are provided to transfer the fuel outside the fuel holding container 16 into the holding container using the flow of fuel (surplus fuel) returned into the fuel holding container 16. It is a thing. Therefore, the fuel outside the fuel holding container 16 can be transferred into the holding container 16 by driving the jet pumps 63 and 65 using the flow of surplus fuel returned into the fuel holding container 16. . Further, the fuel returned into the fuel holding container 16 is at a higher temperature than the fuel outside the fuel holding container 16 due to the heat of the engine 10 and frictional heat due to flow. For this reason, by using the surplus fuel returned into the fuel holding container 16 as a drive source for both the jet pumps 63 and 65, the performance recovery of both the jet pumps 63 and 65 can be accelerated.

  The fuel tank 12 includes a main tank chamber 13 in which a fuel holding container 16 is provided, and a sub tank chamber 14 partitioned from the main tank chamber 13, and fuel returned to the fuel holding container 16 (excess fuel) ) Is used to transfer the fuel in the sub tank chamber 14 into the fuel holding container 16. Accordingly, the fuel in the auxiliary tank chamber 14 can be transferred into the fuel holding container 16 by driving the transfer jet pump 65 using the flow of surplus fuel returned into the fuel holding container 16.

Further, the total amount of fuel transferred by the pumping jet pump 63 and the transfer jet pump 65 is Q1, the amount of fuel supplied from the fuel holding vessel 16 to the engine 10 is Q2, and the fuel holding vessel 16 from the engine 10 is supplied. Assuming that the return fuel amount of the return fuel to the inside is Q3, as the uplifting jet pump 63 and the transfer jet pump 65,
Q1 = Q2-Q3
As long as it has a performance satisfying the above relationship. Therefore, it is sufficient that the pumping pump 63 and the pumping jet 65 for pumping are capable of transporting the total transported fuel amount Q1 that covers the amount of fuel consumed by subtracting the return fuel amount Q3 from the supplied fuel amount Q2. become. As a result, the required value of the transfer fuel amount Q1 required for the pumping jet pump 63 and the transfer jet pump 65 can be reduced, and the two jet pumps 63, 65 can be reduced in size. In this embodiment, the fuel is transferred into the fuel holding container 16 by the two jet pumps 63 and 65, but the fuel is transferred into the fuel holding container 16 by one of the jet pumps. The remaining fuel amount Q1 may be transferred by the remaining jet pump.

[Example 2]
A second embodiment of the present invention will be described. Since the present embodiment is a modification of the first embodiment, the changed portion will be described and redundant description will be omitted. Also, in the following embodiments, the changed parts will be described, and redundant description will be omitted. FIG. 5 is a schematic configuration diagram showing an engine fuel supply device and a fuel addition device.
As shown in FIG. 5, in this embodiment, the return fuel branch pipe 77 is branched from the middle of the return fuel pipe 20 in the first embodiment. The outlet of the return fuel branch pipe 77 is joined to the fuel inlet 45 of the fuel pump 34 for fuel addition.

  According to the fuel addition device 30 of this embodiment, the fuel addition fuel pump 34 sucks the return fuel together with the fuel in the fuel holding container 16. Thus, the return fuel can be sucked together with the fuel in the fuel holding container 16 by the fuel addition fuel pump 34 and supplied to the fuel addition valve 32. Even with such a configuration, the temperature of the fuel supplied to the fuel addition valve 32 can be raised quickly.

[Example 3]
A third embodiment of the present invention will be described. This embodiment is a modification of the second embodiment. FIG. 6 is a schematic configuration diagram showing an engine fuel supply device and a fuel addition device.
As shown in FIG. 6, in this embodiment, a return fuel branch pipe 77 is connected to the fuel inlet 45 of the fuel pump 34 for fuel addition. In this case, the return fuel can be sucked by the fuel addition fuel pump 34 without sucking the fuel in the fuel holding container 16.

[Example 4]
Embodiment 4 of the present invention will be described. This embodiment is a modification of the second embodiment. FIG. 7 is a schematic configuration diagram showing an engine fuel supply device and a fuel addition device.
As shown in FIG. 7, in this embodiment, the return fuel branch pipe 77 in the second embodiment is omitted, and the outlet of the return fuel pipe 20 is joined to the fuel inlet 45 of the fuel pump 34 for fuel addition. It is. In this case, the entire amount of return fuel can be sucked by the fuel pump 34 for fuel addition.

[Example 5]
A fifth embodiment of the present invention will be described. This embodiment is a modification of the first embodiment. FIG. 8 is a schematic configuration diagram showing an engine fuel supply device and a fuel addition device.
As shown in FIG. 8, in this embodiment, the fuel addition device 30 is provided with a valve device 80. The valve device 80 is composed of an electromagnetic three-way switching valve, and includes a total of three connection ports 80a, 80b, and 80c. The first connection port 80a communicates with the vapor jet 50 (see FIG. 2) of the fuel addition fuel pump 34 via a back pressure fuel pipe 82. Further, the second connection port 80 b communicates with the atmosphere opening port 56 of the pressure regulating valve 38, that is, the back pressure chamber 60 (see FIG. 3) via the communication fuel pipe 84. Further, the third connection port 80 c is opened in the fuel holding container 16 through an open pipe 86. The valve device 80 is controlled to be turned on (ON) and turned off (OFF) based on a control signal output from an electronic control unit (referred to as “ECU”) 88.

  Next, in the fuel addition device 30, when the valve device 80 is turned on by a control signal output from the ECU 88, the first connection port 80a and the second connection port 80b are communicated to form the third connection port 80c. Is cut off. Thereby, the pressurized fuel pressure (back pressure) applied in the back pressure fuel pipe 82 acts in the back pressure chamber 60 of the pressure regulating valve 38 (see FIG. 3), and the back pressure chamber 60 to the open pipe 86. The fuel outflow is limited. Therefore, when pressurized fuel pressure acts in the back pressure chamber 60 of the pressure regulating valve 38, the fuel pressure in the back pressure chamber 60 is increased, so that the diaphragm 53 is bent and deformed toward the pressure regulating chamber 62, and the valve body 54 is deformed. As the engine is closed, the fuel discharge in the pressure regulating chamber 62 is restricted, so that the fuel pressure in the pressure regulating chamber 62 further increases. When the fuel pressure in the pressure regulating chamber 62 of the pressure regulating valve 38 (see FIG. 3) becomes larger than the total value of the fuel pressure in the back pressure chamber 60 and the elastic force of the valve spring 55, the diaphragm 53 is on the back pressure chamber 60 side. When the valve body 54 is opened, the fuel in the pressure regulating chamber 62 is discharged as surplus fuel. And if the fuel pressure in the pressure regulation chamber 62 falls again, the diaphragm 53 will bend and deform | transform into the pressure regulation chamber 62 side, and the valve body 54 will be closed. In this way, the fuel pressure in the pressure regulating chamber 62, that is, the fuel pressure supplied to the fuel addition valve 32 is adjusted to a fuel pressure higher than the steady fuel pressure value.

  Further, when the valve device 80 is turned off by a control signal output from the ECU 88, the first connection port 80a is blocked and the second connection port 80b and the third connection port 80c are communicated. As a result, the first connection port 80a of the valve device 80 is blocked, so that the pressurized fuel pressure does not act on the back pressure chamber 60 of the pressure regulating valve 38 (see FIG. 3), and the back pressure chamber of the pressure regulating valve 38. 60 is opened to the atmosphere, that is, the fuel holding container 16 through the connecting fuel pipe 84 and the open pipe 86. Therefore, the force acting on the diaphragm 53 in the back pressure chamber 60 is only the elastic force of the valve spring 55, and the fuel pressure in the pressure regulating chamber 62, that is, the fuel pressure supplied to the fuel addition valve 32 is adjusted to the steady fuel pressure.

  According to the fuel addition device 30 (see FIG. 8), the pressure regulating valve 38 adjusts the pressure of the fuel supplied from the fuel addition fuel pump 34 to the fuel addition valve 32 between a steady fuel pressure and a higher fuel pressure higher than the steady fuel pressure. The pressure can be adjusted in two stages. Therefore, the pressure of the fuel supplied from the fuel addition fuel pump 34 to the fuel addition valve 32 is normally adjusted to a steady fuel pressure by the pressure adjustment valve 38, and is adjusted to a high fuel pressure as necessary, whereby the fuel addition valve 32 is adjusted. From the above, the fuel adhering to the injection end of the fuel addition valve 32 can be blown away by the fuel injected at a high fuel pressure.

[Example 6]
Embodiment 6 of the present invention will be described. This embodiment is a modification of the first embodiment. FIG. 9 is a schematic configuration diagram showing an engine fuel supply device and a fuel addition device.
As shown in FIG. 9, in this embodiment, the fuel holding container 16, the pumping jet pump 63, and the surplus fuel branch pipe 72 in the first embodiment are omitted. Accordingly, the fuel discharge pipe 58 (see FIG. 3) of the pressure regulating valve 38 is communicated with the transfer jet pump 65 (specifically, the inner cylinder 67) via the surplus fuel supply pipe 70. Further, the return fuel branch pipe 90 is branched from the middle of the return fuel pipe 20 in the first embodiment, and the fuel intake port 45 of the fuel addition fuel pump 34 is connected to the suction filter 46 in the first embodiment. Instead, the outlet of the return fuel branch pipe 90 is connected. As a result, the return fuel can be sucked by the fuel pump 34 for fuel addition. In this case, the return fuel can be sucked by the fuel addition fuel pump 34 without sucking the fuel in the fuel holding container 16.

  According to the fuel addition device 30 of the present embodiment, the return fuel is sucked by the fuel addition fuel pump 34. Accordingly, even if the fuel holding container is not provided, the temperature of the fuel supplied to the fuel addition valve 32 can be directly sucked by the fuel addition fuel pump 34 by the return fuel heated by the heat of the engine 10. The temperature can be raised early. This is effective for atomizing the fuel added to the fuel addition valve 32 at the time of low-temperature start, speeding up the performance recovery of the fuel pump 34 for fuel addition, and the like.

  In addition, the fuel tank 12 includes a main tank chamber 13 in which return fuel is returned, and a sub tank chamber 14 partitioned from the main tank chamber 13, and uses the flow of fuel returned into the main tank chamber 13. A jet pump for transferring the fuel in the sub tank chamber 14 into the fuel holding container 16 is provided. Therefore, the fuel in the sub tank chamber 14 of the fuel tank 12 can be transferred into the fuel tank 12 by driving the jet pump using the flow of fuel returned into the fuel tank 12.

The present invention is not limited to the above-described embodiments, and modifications can be made without departing from the gist of the present invention. For example, the present invention can be applied not only to a diesel engine but also to a gasoline engine or the like.
Further, the fuel returned to the fuel holding container and used as the driving fuel for the jet pumps 63 and 65 is not limited to the surplus fuel discharged from the pressure regulating valve 38, but the fuel discharge port 49 of the fuel addition fuel pump 34. The pressurized fuel discharged from the vapor jet 50 or the like, or the return fuel discharged from the return fuel pipe 20 can be used. Further, in the case where the pumping jet pump 63 and the transfer jet pump 65 are provided, the pumping jet pump 63 may be omitted. Further, when the pumping jet pump 63 is omitted, the fuel in the main tank chamber 13 may flow into the fuel holding container 16 using the pressure difference inside and outside the fuel holding container 16. Further, in the case where the pumping jet pump 63 and the transfer jet pump 65 are provided, the fuel in the auxiliary tank chamber 14 may be transferred to the main tank chamber 13 outside the fuel holding container 16 by the transfer jet pump 65. . The number of jet pumps can be increased or decreased as appropriate. Further, when the fuel holding container 16 is provided in the fuel tank 12, the sub tank chamber 14, the transfer jet pump 65, the surplus fuel branch pipe 72, the filter 75, and the like may be omitted. Further, the fuel introduced into the back pressure chamber 60 of the pressure regulating valve 38 is not limited to the fuel discharged from the vapor jet 50 of the fuel addition fuel pump 34, but is discharged from the fuel discharge port 49 of the fuel addition fuel pump 34. Any pressurized fuel discharged from the fuel addition fuel pump 34 can be used.

1 is a schematic configuration diagram illustrating an engine fuel supply device and a fuel addition device according to a first embodiment. It is sectional drawing which shows a fuel pump. It is sectional drawing which shows a pressure regulation valve. It is sectional drawing which shows a jet pump. It is a schematic block diagram which shows the fuel supply apparatus and fuel addition apparatus of the engine which concern on Example 2. FIG. FIG. 6 is a schematic configuration diagram illustrating an engine fuel supply device and a fuel addition device according to a third embodiment. FIG. 6 is a schematic configuration diagram illustrating an engine fuel supply device and a fuel addition device according to a fourth embodiment. FIG. 10 is a schematic configuration diagram illustrating an engine fuel supply device and a fuel addition device according to a fifth embodiment. FIG. 10 is a schematic configuration diagram illustrating an engine fuel supply device and a fuel addition device according to a sixth embodiment. It is a schematic block diagram which shows the fuel supply apparatus and fuel addition apparatus of the engine which concern on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 12 Fuel tank 13 Main tank chamber 14 Sub tank chamber 16 Fuel holding container 23 Fuel supply device 25 Exhaust pipe 30 Fuel addition device 32 Fuel addition valve 34 Fuel addition fuel pump 38 Pressure regulating valve 63 Pumping jet pump 65 Transfer jet pump

Claims (8)

A fuel addition apparatus provided in a fuel supply apparatus configured to supply fuel in a fuel tank to an engine and return surplus return fuel into the fuel tank,
A fuel addition valve for adding fuel to the exhaust passage of the engine;
A fuel pump for fuel addition that supplies fuel in the fuel tank to the fuel addition valve;
A fuel holding container provided in the fuel tank,
A fuel addition apparatus characterized in that fuel supplied to the engine and fuel supplied to the fuel addition valve are stored in the fuel holding container and the return fuel is returned to the fuel holding container. The fuel addition device according to claim 1,
A fuel addition apparatus characterized in that the return fuel is sucked by the fuel addition fuel pump. The fuel addition device according to claim 1 or 2,
A pressure regulating valve that regulates the fuel supplied to the fuel addition valve by the fuel addition fuel pump and discharges surplus fuel that has become surplus,
A fuel addition apparatus characterized in that the surplus fuel discharged from the pressure regulating valve is returned into the fuel holding container. It is a fuel addition apparatus as described in any one of Claims 1-3,
A fuel addition apparatus comprising: a jet pump for transferring fuel outside the fuel holding container into the holding container by using a flow of fuel returned into the fuel holding container. The fuel addition device according to claim 3, wherein
The pressure regulating valve is configured to be capable of regulating the pressure of the fuel supplied from the fuel addition fuel pump to the fuel addition valve in two stages, a steady fuel pressure and a high fuel pressure higher than the steady fuel pressure. A fuel addition device. It is a fuel addition apparatus as described in any one of Claims 1-5,
The fuel tank includes a main tank chamber provided with the fuel holding container, and a sub tank chamber partitioned from the main tank chamber;
A fuel addition apparatus comprising: a transfer jet pump for transferring the fuel in the auxiliary tank chamber into the fuel holding container by using a flow of fuel returned into the fuel holding container. A fuel addition apparatus provided in a fuel supply apparatus configured to supply fuel in a fuel tank to an engine and return surplus return fuel into the fuel tank,
A fuel addition valve for adding fuel to the exhaust passage of the engine;
A fuel addition fuel pump for supplying the fuel in the fuel tank to the fuel addition valve;
A fuel addition apparatus characterized in that the return fuel is sucked by the fuel addition fuel pump. The fuel addition apparatus according to claim 7, wherein
The fuel tank includes a main tank chamber to which the return fuel is returned, and a sub tank chamber partitioned from the main tank chamber;
A fuel addition apparatus, comprising: a transfer jet pump for transferring the fuel in the sub tank chamber into the fuel holding container using the flow of fuel returned into the main tank chamber.

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