JP2008121454A - Fuel supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption by downsizing a fuel pump, in a fuel supply device regulating fuel pressure by a fuel pressure varying device, and transferring fuel by a jet pump. <P>SOLUTION: This fuel supply device 10 is provided with: a fuel tank 12 having fuel storage parts 31 and 32; the fuel pump 14 arranged in the fuel storage part 31; the fuel pressure varying device 18 capable of regulating the pressure of fuel supplied to an engine 45 at two stages; a return passage 20 returning a part of the fuel discharged from the fuel pump 14 into the fuel storage part 31; and the jet pump 22 transferring the fuel in the fuel storage part 32 into the fuel storage part 31. A control valve 24 opening and closing the return passage 20, and an ECU 26 controlling the control valve 24 are arranged. The ECU 26 closes the control valve 24 to stop the jet pump 22 at high fuel pressure by the fuel pressure varying device 18 and at a low voltage. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel supply apparatus mainly used for a vehicle engine.

An example of a conventional fuel supply apparatus is described in Patent Document 1. In addition, FIG. 19 is a block diagram which shows the fuel supply apparatus concerning a prior art example (patent document 1).
As shown in FIG. 19, in the fuel supply apparatus 200 described in Patent Document 1, the fuel in the fuel tank 201 is sucked and pressurized by the fuel pump 202 and passes through the fuel filter 204 to adjust the fuel pressure. After the pressure is adjusted to a predetermined pressure by the device 207, the fuel is injected from each injection valve 205 toward the combustion chamber of the internal combustion engine (engine) through the supply pipe 203. The fuel pressure adjusting device 207 opens and closes the recirculation control valve 224 in response to a control signal from the control unit 229, thereby changing the fuel pressure (referred to as “fuel pressure”) supplied to each injection valve 205 into a high pressure and a low pressure. Switch with. That is, the fuel pressure adjusting device 207 supplies the fuel into the control pressure chamber 208B of the pressure regulator 208 by increasing the pressure in the control pressure chamber 208B by opening the reflux control valve 224 when the engine is started. Along with this, the fuel pressure in the fuel pressure control chamber 208A of the pressure regulator 208 is increased, and the fuel pressure in the supply pipe 203 communicating with the fuel pressure control chamber 208A is increased. Thereby, the fuel pressure supplied to each injection valve 205 becomes a high fuel pressure, atomization of the injected fuel is promoted, and the engine startability is improved. Moreover, the pressure in the control pressure chamber 208B of the pressure regulator 208 is reduced by closing the reflux control valve 224 after the engine is started. Along with this, the fuel pressure in the fuel pressure regulating chamber 208A is lowered, and the fuel pressure in the supply pipe 203 is lowered. Thereby, the fuel pressure supplied to each injection valve 205 becomes a low fuel pressure, so that the load on the fuel pump 202 and the like is reduced.

By the way, it can be considered that the fuel supply device 200 is applied to a fuel tank having two fuel storage units. FIG. 20 is a block diagram showing a fuel supply apparatus according to a modification of the conventional example.
As shown in FIG. 20, the fuel tank 211 is a so-called saddle-shaped tank, and has two fuel storage portions 221 and 222 divided by convex portions 213 protruding in a mountain shape on the bottom plate portion 212. Yes. On the other hand (referred to as “first”), the fuel supply unit 200 is provided in the same manner as described above. A return passage 224 that returns a part of the fuel discharged from the fuel pump 202 into the first fuel storage part 221 is connected to the inner pipe part 203 </ b> A of the supply pipe 203. A jet pump 225 is disposed in the return passage 224. Connected to the jet pump 225 is a communication conduit 226 having a free end communicating with the bottom in the other (“second”) fuel storage unit 222. The jet pump 225 uses the flow of fuel flowing in the return passage 224 to transfer the fuel in the second fuel storage unit 222 into the first fuel storage unit 221. That is, when the fuel flowing in the return passage 224 passes through the jet pump 225, the fuel in the second fuel storage unit 222 is drawn through the communication pipe 226 by the suction force due to the negative pressure generated in the pump. It is transferred into the part 221. As a result, the fuel in the second fuel storage unit 222 not provided with the fuel pump 202 is transferred into the first fuel storage unit 221, thereby supplying the fuel in both the fuel storage units 221 and 222 to the engine. be able to. Incidentally, in a vertical fuel tank, for example, Patent Document 2 discloses a configuration in which fuel in one fuel storage unit is transferred by a jet pump into one fuel storage unit. In addition, the thing of patent document 2 is not provided with the fuel pressure adjustment apparatus which switches a fuel pressure.

JP 2001-90624 A JP-A-63-85254

  In the fuel supply apparatus (see FIG. 20) of the modified example of the conventional example, the voltage applied to the fuel pump 202 is generally a battery voltage of 6 to 10 V (volts) depending on the battery when the engine is started. After starting, the generator increases the generator voltage to 12-14V. Therefore, when the engine is started, since the fuel pump 202 is driven by the battery voltage (low voltage), the rotational speed of the fuel pump 202 is low and the discharge flow rate of the fuel pump 202 is small. Further, after the engine is started, the fuel pressure is increased by the fuel pressure adjusting device 207, so that the amount of fuel flowing out to the jet pump 225 increases. Therefore, since the amount of fuel to the engine decreases when the engine is started, the fuel pump 202 having a large discharge flow rate is used in consideration of the amount of fuel flowing out to the jet pump 225.

Here, the relationship between the discharge pressure of the fuel pump and the discharge flow rate will be described. FIG. 6 is a diagram showing the relationship between the discharge pressure and the discharge flow rate of the fuel pump.
In FIG. 6, the horizontal axis indicates the discharge pressure P, the discharge pressure at the time of starting the engine is indicated by P ₁ , and the discharge pressure after the engine is started is indicated by P ₂ . The vertical axis indicates the discharge flow rate Q. The characteristic line La indicates the discharge flow rate by the normal voltage, and the characteristic line Lb indicates the discharge flow rate by the starting voltage. The discharge flow rate Q and the discharge pressure P are
Q∝√P
Is in a relationship.

In FIG. 6, the discharge flow rate Q ₂ f of the fuel pump required at the time of engine start is
Q ₂ f ≧ Q ₂ E + Q ₂ J
It is. Q ₂ E is a required flow rate of the engine, and Q ₂ J is a flow rate flowing out to the jet pump.
The fuel pump discharge flow rate Q ₁ F required after the engine is started is
Q ₁ F ≧ Q ₁ E + Q ₁ J
It is. Q ₁ E is a required flow rate of the engine, and Q ₁ J is a flow rate flowing out to the jet pump.

The fuel pump must satisfy both the discharge flow rate Q ₁ F after engine start and the discharge flow rate Q ₂ f at engine start. In this case, if the pump size (discharge flow rate) of the fuel pump is determined based on the discharge flow rate Q ₁ F after engine start, the discharge flow rate Q ₂ d at engine start is
Q ₂ d <Q ₂ f
Thus, the discharge flow rate Q ₂ f cannot be satisfied.
For this reason, if the pump size (discharge flow rate) of the fuel pump is determined based on the discharge flow rate Q ₂ f at the time of engine start, the discharge flow rate Q ₁ f after the engine start becomes Q ₁ f> Q ₁ F
Thus, the discharge flow rate Q ₁ F can be satisfied.
However, after starting the engine,
Q ₂ S = Q ₁ f−Q ₁ F
Since the discharge flow rate Q ₂ S required in step 1 becomes surplus, the fuel pump must be enlarged and the power consumption is increased.

  A problem to be solved by the present invention is a fuel supply apparatus that regulates fuel pressure using a fuel pressure variable device and transfers fuel using a jet pump, and can reduce the size of the fuel pump and reduce power consumption. Is to provide.

The above-described problem can be solved by a fuel supply apparatus having the gist of the configuration described in the claims.
That is, according to the fuel supply device of claim 1, the flow of fuel returned to the fuel tank through the return passage when the return passage is opened by opening the return passage control valve by the control device. By operating the jet pump using the fuel, the fuel is transferred from the second fuel storage unit to the first fuel storage unit. Further, when the return passage is closed by closing the return passage control valve by the control device at high fuel pressure and low voltage by the fuel pressure variable device, the flow of fuel returned to the fuel tank through the return passage is reduced. By stopping the operation of the jet pump as it is stopped, the entire amount of fuel discharged from the fuel pump can be supplied to the engine. Therefore, in a fuel supply device that adjusts the fuel pressure with the variable fuel pressure device and transfers the fuel with the jet pump, the fuel flow rate of the fuel pump at the time of high fuel pressure and low voltage by the variable fuel pressure device is reduced. A pump can be reduced in size and power consumption can be reduced.

  In the fuel supply device according to claim 2 of the claims, the fuel remaining in the first fuel storage unit detected by the fuel remaining amount detection device at the low fuel pressure by the fuel pressure variable device and at the normal voltage. When the amount is less than or equal to the predetermined amount, the control device opens the return passage control valve to operate the jet pump, thereby transferring the fuel from the second fuel storage unit to the first fuel storage unit. Is called. Accordingly, it is possible to avoid a situation in which the fuel supply is disabled due to a decrease in the remaining amount of fuel in the first fuel storage unit, even though fuel remains in the second fuel storage unit.

  According to the fuel supply device of claim 3, the low pressure side pressure regulator is activated when the low pressure side return passage is opened by opening the low pressure side return passage control valve by the control device. Thus, the fuel pressure supplied to the engine can be regulated to a low pressure. At this time, the high pressure side pressure regulator is not operated. Further, when the low pressure side return passage is closed by closing the control valve for the low pressure side return passage by the control device, the high pressure side pressure regulator is operated as the operation of the low pressure side pressure regulator is stopped. The fuel pressure supplied to the engine can be adjusted to a high pressure.

  According to the fuel supply device of claim 4 of the claims, the control valve opens and closes the control pressure chamber side return passage control valve, so that the pressure as the control pressure chamber side return passage opens and closes. By adjusting the pressure in the control pressure chamber of the regulator in at least two stages, the fuel pressure supplied to the engine can be adjusted. The fuel pressurized by the fuel pump as the fuel led to the control pressure chamber of the pressure regulator includes the fuel discharged from the fuel discharge port of the fuel pump, and the fuel discharge port to the fuel pump (for example, the motor unit). The fuel discharged from the fuel outlet provided separately, the fuel discharged from the vapor fuel outlet of the pump passage during the pressurization of the fuel pump, that is, the fuel discharged from the vapor fuel outlet of the pump passage, and the vapor fuel outlet of the pump passage during the pressurization of the fuel pump The fuel discharged from the fuel outlet provided separately can be utilized.

  According to the fuel supply device of claim 5 of the present invention, the fuel supply device includes a pressure control valve for controlling the fuel pressure in the fuel pressure regulating chamber and / or the control pressure chamber of the pressure regulator to a set pressure or lower. is there. Thereby, the fuel pressure in the fuel pressure adjusting chamber and / or the control pressure chamber of the pressure regulator can be controlled to be equal to or lower than the set value. The pressure control valve is disposed on the fuel passage that communicates with the fuel pressure adjustment chamber and forms the same fuel pressure as the fuel pressure in the fuel pressure adjustment chamber, thereby controlling the fuel pressure in the fuel pressure adjustment chamber below the set pressure. Can do. Further, the pressure control valve is arranged on the fuel passage communicating with the control pressure chamber and having the same fuel pressure as the fuel pressure in the control pressure chamber, so that the fuel pressure in the control pressure chamber can be controlled to be equal to or lower than the set pressure.

  Next, the best mode for carrying out the present invention will be described with reference to examples.

[Example 1]
A first embodiment of the present invention will be described. The fuel supply device of this embodiment is used for a vehicle engine. FIG. 1 is a block diagram showing the fuel supply device.
As shown in FIG. 1, the fuel supply device 10 includes a fuel tank 12, a fuel pump 14, a fuel filter 16, a fuel pressure variable device 18, a return passage 20, a jet pump 22, a return passage control valve 24, and an electronic control device (" ECU ”) 26). Hereinafter, it demonstrates in order. The fuel pump 14, the fuel filter 16, and the fuel pressure variable device 18 constitute a fuel supply unit 28.

  The fuel tank 12 will be described. The fuel tank 12 includes a first fuel storage unit 31 and a second fuel storage unit 32. As described above, the fuel tank 12 having the two fuel storage units 31 and 32 corresponds to, for example, a vertical fuel tank and a fuel tank with a built-in reservoir cup. 2 is a cross-sectional view showing a saddle type fuel tank, and FIG. 3 is a cross-sectional view showing a fuel tank with a built-in reservoir cup.

  Describe the vertical fuel tank. As shown in FIG. 2, the vertical fuel tank 12 (reference numeral (1) is attached) is divided into two fuel storage parts 31, which are divided by convex parts 34 protruding in a mountain shape on the bottom plate part 33. 32. In the case of the vertical fuel tank 12 (1), the fuel storage section 31 on the side where the fuel supply section 28 is disposed (left side in FIG. 2) corresponds to the “first fuel storage section” and the other side (FIG. The right side fuel storage portion 32 corresponds to the “second fuel storage portion”.

  A fuel tank with a built-in reservoir cup will be described. As shown in FIG. 3, the reservoir tank built-in type fuel tank 12 (reference numeral (2)) is provided with a reservoir cup (also referred to as a sub tank) 36 at the bottom of the fuel tank 12 (2). It is. The fuel supply unit 28 is disposed in the reservoir cup 36. Therefore, in the case of the fuel tank 12 (2) with a built-in reservoir cup, the fuel storage unit 31 in the reservoir cup 36 corresponds to the “first fuel storage unit”, and the fuel storage unit 32 outside the reservoir cup 36 is the “first fuel storage unit”. It corresponds to "2 fuel storage part".

  As shown in FIG. 1, an in-tank fuel supply passage 38 communicating with an out-tank fuel supply passage 39 is provided in the fuel tank 12. The tank fuel supply passage 38 communicates with a fuel outlet of a filter case of the fuel filter 16 (described later). Further, the fuel discharged to the fuel supply passage 39 outside the tank through the tank fuel supply passage 38 is supplied to the delivery pipe 42. The delivery pipe 42 is disposed on the engine 45 side and includes respective fuel injection valves so-called injectors 43 corresponding to the respective combustion chambers (not shown). Therefore, the fuel supplied to the delivery pipe 42 is injected from each injector 43 into each combustion chamber of the engine 45.

  Next, the fuel pump 14 will be described. FIG. 4 is a cross-sectional view showing the fuel pump. As shown in FIG. 4, the fuel pump 14 is of a motor integrated type including an electric motor unit 47 and an impeller pump unit 48 provided at the lower end of the motor unit 47. When the impeller 49 is rotated by driving the motor unit 47, the pump unit 48 sucks and pressurizes the fuel in the first fuel storage unit 31 (see FIG. 1) and discharges it into the motor unit 47. To do. Further, a fuel suction port 50 for sucking fuel is provided on the lower surface side of the fuel pump 14, and a fuel discharge port 52 for discharging fuel circulated in the motor unit 47 is provided on the upper surface side. Further, a vapor jet 54 is provided on the lower surface side of the fuel pump 14 for discharging, that is, discharging, vapor (bubbles generated when the fuel is vaporized) contained in the fuel being pressurized by the pump unit 48 from the pump passage. ing. The vapor jet 54 corresponds to a “vapor fuel discharge port” in this specification. In addition, a suction filter 56 for filtering fuel sucked into the fuel pump 14 from the first fuel storage unit 31 is communicated with the fuel suction port 50 of the fuel pump 14.

  Next, the fuel filter 16 will be described. Although not shown, the fuel filter 16 includes a filter case and a filter element accommodated in the filter case. A fuel discharge port 52 of the fuel pump 14 communicates with a fuel inlet of the filter case by a pipe connection. The tank fuel supply passage 38 (see FIG. 1) communicates with the outlet of the filter case. As shown in FIG. 1, the fuel discharged from the fuel pump 14 into the fuel filter 16 is filtered by the fuel filter 16 (specifically, a filter element), and then from the fuel outlet of the filter case to the fuel supply passage in the tank. Then, the fuel is discharged to the fuel supply passage 39 outside the tank. Thus, two recirculation passages, that is, a high-pressure recirculation passage 58 and a low-pressure recirculation passage 59 are branched from the in-tank fuel supply passage 38.

  Next, the fuel pressure variable device 18 will be described. As shown in FIG. 1, the fuel pressure variable device 18 includes a high pressure side pressure regulator 60 (reference numeral, (H)), a low pressure side pressure regulator 60 (reference numeral, (L)), and a low pressure side return passage. And a control valve 62 so that the fuel pressure supplied from the fuel pump 14 to the engine 45 can be regulated in two stages. The high pressure side pressure regulator 60 (H) and the low pressure side pressure regulator 60 (L) differ only in the pressure regulation value, and the basic configuration is the same pressure regulator (also called a pressure regulator, a pressure regulation valve, etc.) 60. It is. FIG. 5 is a cross-sectional view showing the pressure regulator.

  The pressure regulator 60 will be described. As shown in FIG. 5, the pressure regulator 60 includes a casing 64, a diaphragm 65, a valve body 66, and the like. The casing 64 forms an outer shell of the pressure regulator 60, and is formed by joining a case 67 on the fuel pressure regulation chamber side having an upper surface opening shape and a case 68 on the control pressure chamber side having an opening shape on the lower surface. A fuel inlet 70 is formed in the side wall of the case 67 on the fuel pressure regulating chamber side. A straight tubular fuel discharge pipe 71 is integrated on the same axis line with the bottom wall portion of the case 67 on the fuel pressure regulating chamber side. A pair of opening holes 72 and 73 are formed in the side wall portion of the case 68 on the control pressure chamber side.

  The diaphragm 65 is sandwiched between a case 67 on the fuel pressure regulating chamber side and a case 68 on the control pressure chamber side, and the casing 64 is partitioned into a fuel pressure regulating chamber 75 and a control pressure chamber 76. is doing. The diaphragm 65 is formed of a rubber-like elastic material and has flexibility. The valve body 66 is provided at the center of the diaphragm 65 and faces the upper end surface of the fuel discharge pipe 71. The valve body 66 opens or closes with the upper end surface of the fuel discharge pipe 71 as a valve seat by bending deformation of the diaphragm 65, thereby communicating or blocking the inside of the fuel pressure regulating chamber 75 with respect to the fuel discharge pipe 71. The diaphragm 65 corresponds to a “movable partition wall” in this specification.

  In the control pressure chamber 76, a valve spring 78 made of a coil spring is interposed between the upper wall portion of the case 68 on the control pressure chamber side and the valve body 66 of the diaphragm 65. The valve spring 78 always urges the valve body 66 in a direction in which the valve body 66 is seated on the valve seat of the fuel discharge pipe 71, that is, a valve closing direction. Therefore, when the fuel pressure that presses the diaphragm 65 in the fuel pressure regulating chamber 75 is lower than the force that presses the diaphragm 65 in the control pressure chamber 76, that is, the elastic force of the valve spring 78, the elastic force of the valve spring 78. Thus, the valve body 66 is seated on the fuel discharge pipe 71, whereby the fuel discharge pipe 71 is closed. Further, when the fuel pressure in the fuel pressure adjusting chamber 75, that is, the fuel pressure that presses the diaphragm 65 becomes higher than the elastic force of the valve spring 78, the valve body 66 is separated from the fuel discharge pipe 71 by the bending deformation of the diaphragm 65. The fuel discharge pipe 71 is opened. Thereby, since the fuel in the fuel pressure regulation chamber 75 is discharged through the fuel discharge pipe 71, the fuel pressure in the fuel pressure regulation chamber 75 is lowered until it reaches a set value. When the fuel pressure in the fuel pressure adjusting chamber 75 reaches a set value, the valve body 66 is closed by the elasticity of the valve spring 78.

  The high-pressure side recirculation passage 58 communicates with the fuel inlet 70 of the high-pressure side pressure regulator 60 (H) (see FIG. 1). Further, the low pressure side recirculation passage 59 communicates with the fuel introduction port 70 of the low pressure side pressure regulator 60 (L) (see FIG. 1). Further, the fuel discharge pipe 71 and the two opening holes 72 and 73 of both pressure regulators 60 are opened in the first fuel storage unit 31. Therefore, the valve spring 78 in the high pressure side pressure regulator 60 (H) is set so that the fuel pressure in the fuel pressure regulating chamber 75 becomes a predetermined pressure regulation value, for example, about 600 kPa (kilopascal). Further, the valve spring 78 in the low pressure side pressure regulator 60 (L) is set so that the fuel pressure in the fuel pressure regulating chamber 75 becomes a predetermined pressure regulation value, for example, about 400 kPa.

  The low pressure side reflux passage control valve 62 will be described. As shown in FIG. 1, the low pressure side reflux passage control valve 62 is incorporated in the low pressure side reflux passage 59. The low-pressure-side return passage control valve (hereinafter referred to as “fuel pressure variable control valve”) 62 includes, for example, an electromagnetic on-off valve, an electromagnetic flow control valve, and the like, and is based on a control signal from the ECU 26. Opened and closed. The ECU 26 closes the fuel pressure variable control valve 62 from the start of the engine 45 (ON of an ignition switch or a start switch such as a start switch) until a predetermined time has elapsed after the completion of the start, and the predetermined time has elapsed. Thereafter, the control valve 62 is set to open.

When the ECU 26 opens the fuel pressure varying control valve 62, the low pressure side recirculation passage 59 is opened, so that the fuel enters the fuel pressure adjusting chamber 75 of the low pressure side pressure regulator 60 (L) through the low pressure recirculation passage 59. Flows in, the low pressure side pressure regulator 60 (L) operates. Thereby, the fuel pressure supplied to the engine 45 is regulated to a low fuel pressure (about 400 kPa). At this time, the high-pressure side pressure regulator 60 (H) is not activated and maintains a closed state.
Further, when the fuel pressure varying control valve 62 is closed by the ECU 26, the low pressure side recirculation passage 59 is closed, so that the operation of the low pressure side pressure regulator 60 (L) is stopped. At this time, the low pressure side pressure regulator 60 (L) maintains the closed state. Accordingly, the fuel flows into the fuel pressure adjustment chamber 75 of the high pressure side pressure regulator 60 (H) through the high pressure side recirculation passage 58, whereby the high pressure side pressure regulator 60 (H) is operated. Thereby, the fuel pressure supplied to the engine 45 is adjusted to a high fuel pressure (about 600 kPa).

  Next, the return passage 20 will be described. As shown in FIG. 1, the return passage 20 is branched from the tank fuel supply passage 38. The branch position of the litter passage 20 with respect to the fuel supply passage 38 in the tank is set on the downstream side of both the reflux passages 58 and 59. The return passage 20 is not limited to the fuel supply passage 38 in the tank, and can be branched from the fuel passage as long as it has the same fuel pressure as the fuel pressure in the fuel supply passage 38 in the tank.

Next, the jet pump 22 will be described. Since the jet pump 22 has the same configuration as the jet pump 22 described in Patent Document 2, detailed description thereof is omitted.
The jet pump 22 is connected to the return passage 20 and transfers the fuel in the second fuel storage portion 32 into the first fuel storage portion 31 using the flow of fuel flowing in the return passage 20. . That is, when the fuel flowing in the return passage 20 passes through the jet pump 22, the fuel in the second fuel storage section 32 is connected to the first via the communication pipe 80 by the suction force due to the negative pressure generated in the pump. It is transferred into the fuel storage unit 31. As a result, the fuel in the second fuel storage unit 32 that does not include the fuel pump 14 is transferred into the first fuel storage unit 31 so that the fuel in both the fuel storage units 31 and 32 is supplied to the engine 45. can do.

  Next, the return passage control valve 24 will be described. The return passage control valve 24 is incorporated in the return passage 20. The return passage control valve (hereinafter, referred to as “jet pump control valve”) 20 includes, for example, an electromagnetic on-off valve, an electromagnetic flow control valve, and the like, and is opened and closed based on a control signal from the ECU 26. The The ECU 26 closes the jet pump control valve 24 from the start of the engine 45 (ON of an ignition switch or a start switch such as a start switch) to immediately after the completion of the start, and the control is performed after the predetermined time has elapsed. The valve 24 is set to open.

  Next, the ECU 26 will be described. The ECU 26 is a control unit constituted by a microcomputer or the like. On the input side thereof, for example, a start switch such as an ignition switch or a start switch of the engine 45, a throttle position sensor, a flow rate sensor for intake air, a crank angle sensor, and the like are provided. A detection device is connected, and an injector 43, a jet pump control valve 24, a fuel pressure varying control valve 62, and the like are connected to the output side. As described above, the ECU 26 is set to perform opening / closing control of the jet pump control valve 24 and the fuel pressure variable control valve 62 in accordance with the operating state of the engine 45.

  Next, the operation of the fuel supply device 10 will be described. When the engine 45 starts to be started by the start switch, the control signal 62 from the ECU 26 closes the fuel pressure variable control valve 62 of the fuel pressure variable device 18 so that the low pressure side pressure regulator 60 (L) does not operate. I'm left. Therefore, the pressure of the fuel supplied to the engine 45 is adjusted to a high fuel pressure (about 600 kPa) by the high pressure side pressure regulator 60 (H). Thereby, since the fuel pressure supplied to the engine 45 becomes a high fuel pressure, atomization of the injected fuel is promoted, and the startability of the engine 45 is improved.

  Further, when the engine is started, since the fuel pump 14 is driven by a battery voltage of 6 to 10 V (volts) by a battery (vehicle battery), the rotational speed of the fuel pump 14 is low and the discharge flow rate is small. In this specification, “when the engine is started” refers to a period from the start of engine start (ON of the start switch) to the completion of start. The battery voltage is referred to as “starting voltage” and “low voltage”.

  At high fuel pressure and low voltage by the fuel pressure varying device 18, the return path 20 is closed by closing the jet pump control valve 24 by the control signal from the ECU 26, and the jet pump 22 does not operate. Put in condition. Accordingly, the entire amount of fuel discharged from the fuel pump 14 is supplied to the engine 45.

  Further, after the engine is started, the fuel pump 14 is driven with a generator voltage of 12 to 14 V by the generator, so that the rotation speed of the fuel pump 14 is high and the discharge flow rate is large. For this reason, after the engine is started, the return passage 20 is opened by opening the jet pump control valve 24 by a control signal from the ECU 26. Then, a fuel flow returned to the fuel tank 12 through the return passage 20 is generated, and the jet pump 22 using this flow is operated, whereby the fuel from the first fuel storage unit 31 to the second fuel storage unit 32 is produced. Is transferred. As used herein, “after engine start” refers to a normal operating state after the completion of engine start. The generator voltage is referred to as “normal voltage” or “high voltage”.

  In addition, after a predetermined time has elapsed after the start of the engine 45, the fuel pressure variable control valve 62 is opened by a control signal from the ECU 26, whereby the low pressure side pressure regulator 60 (L) is operated. Therefore, the pressure of the fuel supplied to the engine 45 is regulated to a low fuel pressure (about 400 kPa) by the low pressure side pressure regulator 60 (L). Thereby, the load concerning the fuel pump 14 etc. is reduced.

  According to the fuel supply device 10 described above, when the return passage 20 is closed by closing the jet pump control valve 24 by the ECU 26 at the time of high fuel pressure and low voltage by the fuel pressure variable device 18, the return passage 20 is closed. The operation of the jet pump 22 is stopped as the flow of fuel returned to the fuel tank 12 through is stopped. As a result, since the entire amount of fuel discharged from the fuel pump 14 is supplied to the engine 45, the flow rate burden of the fuel pump 14 can be reduced.

Here, the relationship between the discharge pressure of the fuel pump and the discharge flow rate will be described. In FIG. 6, the characteristic line LA indicates the discharge flow rate by the normal voltage, and the characteristic line LB indicates the discharge flow rate by the starting voltage.
According to the fuel supply apparatus of the present embodiment, the discharge flow rate Q ₂ F of the fuel pump required when starting the engine is
Q ₂ F ≧ Q ₂ E
It is. Q ₂ E is the required flow rate of the engine.
The fuel pump discharge flow rate Q ₁ F required after the engine is started is
Q ₁ F ≧ Q ₁ E + Q ₁ J
It is. Q ₁ E is a required flow rate of the engine, and Q ₁ J is a flow rate flowing out to the jet pump.

For this reason, when the conditions of both the discharge flow rate Q ₁ F after engine start and the discharge flow rate Q ₂ F at engine start are satisfied, the condition of the discharge flow rate Q ₂ F at engine start becomes the discharge flow rate Q ₂ f. Compared to the discharge flow rate Q ₁ F at the time of starting the engine, the pump size (discharge flow rate) of the fuel pump 14 may be determined based on the discharge flow rate Q ₁ F at the time of starting the engine. A fuel pump 14 of an appropriate pump size that produces little flow can be used.

  Therefore, in the fuel supply device 10 that regulates the fuel pressure by the variable fuel pressure device 18 and transfers the fuel by the jet pump 22, the flow rate burden of the fuel pump 14 at the time of high fuel pressure and low voltage by the variable fuel pressure device 18 is reduced. By doing so, the fuel pump 14 can be reduced in size and power consumption can be reduced.

In addition, when the low pressure side recirculation passage 59 is opened by opening the fuel pressure variable control valve 62 by the ECU 26, the low pressure side pressure regulator 60 (L) is activated to reduce the fuel pressure supplied to the engine 45 to a low pressure. The pressure can be adjusted. At this time, the high pressure side pressure regulator 60 (H) is not operated.
When the low pressure side recirculation passage 59 is closed by closing the fuel pressure varying control valve 62 by the ECU 26, the operation of the low pressure side pressure regulator 60 (L) is stopped and the high pressure side pressure regulator 60 (H ) Operates, the fuel pressure supplied to the engine 45 can be adjusted to a high pressure.

[Example 2]
A second embodiment of the present invention will be described. In the present embodiment, a part of the first embodiment is changed. Therefore, the changed portion will be described and redundant description will be omitted. In the following embodiments, the same description will be omitted. FIG. 7 is a block diagram showing the fuel supply device.
As shown in FIG. 7, the present embodiment is a modification of the fuel pressure variable device 18 (see FIG. 1) in the first embodiment. That is, the fuel pressure variable device (denoted by reference numeral 82) of this embodiment includes a pressure regulator 60 and a control pressure chamber side return passage control valve 84, and the fuel pressure supplied from the fuel pump 14 to the engine 45. The pressure can be adjusted in two stages. In addition, the pressure regulator 60 of a present Example is corresponded to the low voltage | pressure side pressure regulator 60 (L) in the said Example 1 (refer FIG. 1). Further, instead of the high pressure side return passage 58 and the low pressure side return passage 59 in the first embodiment, a control pressure chamber side return passage 86 and a fuel pressure regulating chamber side return passage 87 are branched from the in-tank fuel supply passage 38. ing.

  The fuel pressure adjusting chamber-side return passage 87 communicates with the fuel inlet 70 (see FIG. 5) of the pressure regulator 60. A fuel discharge pipe 71 of the pressure regulator 60 is opened in the first fuel storage unit 31. Accordingly, one of the pair of opening holes 72 and 73 (see FIG. 5) formed in the case 68 on the control pressure chamber side of the pressure regulator 60 is provided in the control pressure chamber side return passage 86. Is communicated. A fuel outflow pipe 88 is connected to the other opening hole 73. The fuel outflow pipe 88 is open to the first fuel storage unit 31. The fuel outflow pipe 88 is provided with a throttle 89 that restricts the outflow of fuel to a predetermined amount.

  The control pressure chamber side return passage control valve 84 is incorporated in the control pressure chamber side return passage 86. The control pressure chamber side recirculation passage control valve (hereinafter referred to as “fuel pressure variable control valve”) 84 is composed of, for example, an electromagnetic on-off valve, an electromagnetic flow control valve, and the like. Open and close based on. The ECU 26 opens the fuel pressure varying control valve 84 from the start of the engine 45 (ON of an ignition switch or a start switch such as a start switch) until a lapse of a predetermined time after the completion of the start, and after the lapse of the predetermined time. Thereafter, the control valve 84 is set to be closed.

  When the ECU 26 opens the fuel pressure varying control valve 84, the control pressure chamber side recirculation passage 86 is opened, so that fuel flows into the control pressure chamber 76 of the pressure regulator 60 through the control pressure chamber recirculation passage 86. To do. At this time, since the outflow of fuel in the control pressure chamber 76 is restricted by the throttle 89 provided in the fuel outflow pipe 88, the fuel pressure in the control pressure chamber 76 of the pressure regulator 60 rises to a predetermined control pressure. . Accordingly, when the diaphragm 65 is bent and deformed toward the fuel pressure adjusting chamber 75 and the valve body 66 is seated on the valve seat of the fuel discharge pipe 71, the outflow of fuel in the fuel pressure adjusting chamber 75 is restricted. For this reason, the fuel pressure in the fuel pressure regulation chamber 75 rises. When the fuel pressure in the fuel pressure regulating chamber 75 of the pressure regulator 60 becomes larger than the fuel pressure in the control pressure chamber 76, the diaphragm 65 is bent and deformed toward the control pressure chamber, and the valve body 66 is seated on the fuel discharge pipe 71. As a result, the fuel in the fuel pressure adjustment chamber 75 is discharged into the first fuel storage unit 31 through the fuel discharge pipe 71. When the fuel pressure in the fuel pressure adjusting chamber 75 decreases again, the diaphragm 65 is bent and deformed toward the fuel pressure adjusting chamber 75, and the valve body 66 is seated on the valve seat of the fuel discharge pipe 71. Thereby, the fuel pressure in the fuel pressure adjusting chamber 75, that is, the pressure of the fuel supplied to the engine 45 is adjusted to a predetermined pressure adjustment value, for example, about 600 kPa.

  When the fuel pressure varying control valve 84 is opened by the ECU 26, the control pressure chamber side return passage 86 is closed. As a result, the pressure acting on the diaphragm 65 within the control pressure chamber 76 of the pressure regulator 60 is only the elastic force of the valve spring 78. Therefore, when the pressure regulator 60 functions as the low pressure side pressure regulator 60 (L), the fuel pressure in the fuel pressure regulating chamber 75, that is, the pressure of the fuel supplied to the engine 45 is a predetermined pressure regulation value, for example, about 400 kPa. The pressure is adjusted to the extent.

According to the present embodiment, when the fuel pressure varying control valve 84 is opened and closed by the ECU 26, the pressure in the control pressure chamber 76 of the pressure regulator 60 is adjusted in two steps as the control pressure chamber side return passage 86 is opened and closed. By being pressurized, the fuel pressure supplied to the engine 45 can be regulated. Note that the pressure in the control pressure chamber 76 of the pressure regulator 60 can be regulated in three or more stages by opening and closing the control pressure chamber side reflux passage 86 in three or more stages by the fuel pressure varying control valve 84.
Further, as the fuel introduced into the control pressure chamber 76 of the pressure regulator 60, the fuel discharged from the fuel discharge port 52 of the fuel pump 14 can be used. The fuel discharged from the fuel discharge port 52 of the fuel pump 14 corresponds to “fuel pressurized by the fuel pump” in this specification. Further, in place of the fuel discharged from the fuel discharge port 52 of the fuel pump 14, the fuel discharged from the fuel outlet provided separately from the fuel discharge port 52 in the motor unit 47 of the fuel pump 14 is used. May be.
Further, the pressure regulator 60 can be reduced to one as compared with that of the first embodiment (see FIG. 1), and the configuration can be simplified.

[Example 3]
A third embodiment of the present invention will be described. FIG. 8 is a block diagram showing the fuel supply device.
As shown in FIG. 8, the present embodiment is a modification of the fuel pressure variable device 18 (see FIG. 1) in the first embodiment. This fuel pressure variable device (reference numeral 90 is attached) has the high pressure side pressure regulator 60 (H) arranged outside the fuel tank 12. That is, the high pressure side recirculation passage 58 communicating with the fuel pressure regulating chamber 75 of the high pressure side pressure regulator 60 (H) is provided between the delivery pipe 42 on the engine 45 side and the injector 43 instead of the fuel supply passage 38 in the tank. Is branched from the fuel flow path 92 in FIG. The fuel discharge pipe 71 of the high pressure side pressure regulator 60 (H) is connected to discharge the fuel into the fuel tank 12.

[Example 4]
Embodiment 4 of the present invention will be described. FIG. 9 is a block diagram showing the fuel supply device.
As shown in FIG. 9, the present embodiment is a modification of the second embodiment (see FIG. 7). That is, the control pressure chamber side reflux passage 86 communicating with the control pressure chamber 76 of the pressure regulator 60 is communicated with the vapor jet 54 (see FIG. 4) of the fuel pump 14 instead of the tank fuel supply passage 38. Has been. The control pressure chamber-side return passage 86 is provided with a throttle 94 that restricts the flow of fuel flowing from the vapor jet 54 of the fuel pump 14 to the control pressure chamber 76 of the pressure regulator 60 to a predetermined amount.

  Further, the fuel pressure varying control valve 84 (reference numeral A) is incorporated in the fuel outlet pipe 88 of the pressure regulator 60 in place of the control pressure chamber-side return passage 86. In contrast to the fuel pressure variable control valve 84 in the second embodiment, the ECU 26 starts from the start of the engine 45 (ON of an ignition switch or a start switch such as a start switch) until a predetermined time elapses after the start is completed. Is set so that the fuel pressure variable control valve 84A is closed and the fuel pressure variable control valve 84A is opened after the predetermined time has elapsed.

  When the ECU 26 closes the fuel pressure varying control valve 84A, the fuel outflow pipe 88 is closed, so that the fuel outflow in the control pressure chamber 76 of the pressure regulator 60 is restricted. Here, since the fuel discharged (discharged) from the vapor jet 54 of the fuel pump 14 is supplied into the control pressure chamber 76 of the pressure regulator 60 through the control pressure chamber-side return passage 86, the control pressure chamber of the pressure regulator 60. The fuel pressure in 76 rises to a predetermined control pressure. Accordingly, when the diaphragm 65 is bent and deformed toward the fuel pressure adjusting chamber 75 and the valve body 66 is seated on the valve seat of the fuel discharge pipe 71, the outflow of fuel in the fuel pressure adjusting chamber 75 is restricted. For this reason, the fuel pressure in the fuel pressure regulation chamber 75 rises. When the fuel pressure in the fuel pressure regulating chamber 75 of the pressure regulator 60 becomes larger than the fuel pressure in the control pressure chamber 76, the diaphragm 65 is bent and deformed toward the control pressure chamber, and the valve body 66 is seated on the fuel discharge pipe 71. As a result, the fuel in the fuel pressure adjustment chamber 75 is discharged into the first fuel storage unit 31 through the fuel discharge pipe 71. When the fuel pressure in the fuel pressure adjusting chamber 75 decreases again, the diaphragm 65 is bent and deformed toward the fuel pressure adjusting chamber 75, and the valve body 66 is seated on the valve seat of the fuel discharge pipe 71. Thereby, the fuel pressure in the fuel pressure adjusting chamber 75, that is, the pressure of the fuel supplied to the engine 45 is adjusted to a predetermined pressure adjustment value, for example, about 600 kPa.

When the fuel pressure varying control valve 84A is opened by the ECU 26, the fuel outflow pipe 88 is opened, so that the fuel in the control pressure chamber 76 of the pressure regulator 60 passes through the fuel outflow pipe 88 to the first fuel storage section. It flows out in 31. As a result, the pressure acting on the diaphragm 65 within the control pressure chamber 76 of the pressure regulator 60 is only the elastic force of the valve spring 78. Therefore, the pressure regulator 60 functions as the low pressure side pressure regulator 60 (L), so that the fuel pressure in the fuel pressure regulating chamber 75, that is, the pressure of the fuel supplied to the engine 45 is a predetermined pressure regulation value, for example, about 400 kPa. The pressure is adjusted to the extent.
According to this embodiment, the fuel discharged from the vapor jet 54 of the fuel pump 14 can be used as the fuel introduced into the control pressure chamber 76 of the pressure regulator 60. The fuel discharged from the vapor jet 54 of the fuel pump 14 corresponds to “fuel pressurized by the fuel pump” in this specification. Further, in place of the fuel discharged from the vapor jet 54 of the fuel pump 14, the fuel discharged from the fuel outlet provided separately from the vapor jet 54 in the pump passage during the pressurization of the fuel pump 14 is used. May be.

[Example 5]
A fifth embodiment of the present invention will be described. FIG. 10 is a block diagram showing the fuel supply device.
As shown in FIG. 10, the present embodiment is a modification of the first embodiment (see FIG. 1). That is, a fuel remaining amount meter 96 for detecting the remaining amount of fuel in the fuel storage unit is provided in the first fuel storage unit 31 of the fuel tank 12. A detection signal from the fuel fuel gauge 96 is input to the ECU 26. The ECU 26 opens the jet pump control valve 24 when the fuel remaining amount detected by the fuel remaining amount gauge 96 is equal to or less than a predetermined amount at low fuel pressure by the fuel pressure varying device 18 and at normal voltage. The jet pump 22 is set to operate, and when the fuel remaining amount detected by the fuel remaining amount meter 96 exceeds a predetermined amount, the jet pump control valve 24 is kept closed. The fuel remaining amount meter 96 corresponds to a “fuel remaining amount detecting device” in this specification.

  According to the present embodiment, when the fuel remaining amount in the first fuel storage unit 31 detected by the fuel remaining amount meter 96 is equal to or less than a predetermined amount at low fuel pressure by the fuel pressure varying device 18 and at normal voltage, the ECU 26 By opening the jet pump control valve 24 and operating the jet pump 22, the fuel is transferred from the second fuel storage unit 32 to the first fuel storage unit 31. Accordingly, it is possible to avoid a situation in which the fuel supply cannot be performed because the remaining amount of fuel in the first fuel storage unit 31 is reduced even though the fuel remains in the second fuel storage unit 32.

[Example 6]
Embodiment 6 of the present invention will be described. FIG. 11 is a block diagram showing the fuel supply device.
As shown in FIG. 11, the present embodiment is a modification of the fifth embodiment (see FIG. 10). That is, the fuel pump 14 of this embodiment includes a pump controller 98. The pump controller 98 controls the voltage applied to the fuel pump 14 based on the control signal from the ECU 26, thereby varying the discharge flow rate in a plurality of stages (four stages in this embodiment). The ECU 26 is configured to stop the jet pump 22 (when the jet pump control valve 24 is closed) when the remaining amount of fuel in the first fuel storage unit 31 detected by the fuel fuel gauge 96 exceeds a predetermined amount. In this case, by controlling the pump controller 98, the fuel pump 14 is driven at a flow rate Q2 having a large discharge flow rate when the engine is started, and after the engine is started, the fuel pump 14 is driven at a flow rate Q1 having a low discharge flow rate. Yes. In addition, the ECU 26 detects when the remaining amount of fuel in the first fuel storage unit 31 detected by the fuel remaining amount meter 96 is equal to or less than a predetermined amount and when the jet pump 22 is activated (control valve for jet pump (control for return passage) When the engine is started, the fuel pump 14 is driven at a flow rate Q4 with a large discharge flow rate, and after the engine is started, the fuel pump 14 is changed to a flow rate Q3 with a low discharge flow rate. It is set to be. The ratio of the flow rates Q1, Q2, Q3, and Q4 is set such that, for example, when the flow rate Q2 is 100, the flow rate Q1 is 50, the flow rate Q3 is 80, and the flow rate Q4 is 130.

  According to the present embodiment, the ECU 26 controls the pump controller 98 in accordance with the remaining amount of fuel in the first fuel storage unit 31, the state of the jet pump 22, and the operating state of the engine 45. In this configuration, the flow rate is variably controlled in four stages of Q1, Q2, Q3, and Q4. Accordingly, the fuel pump 14 can be appropriately driven and controlled.

[Example 7]
A seventh embodiment of the present invention will be described. FIG. 12 is a block diagram showing the fuel supply device.
As shown in FIG. 12, the present embodiment is a modification of the sixth embodiment (see FIG. 11). That is, the detection signal of the fuel remaining amount meter 96 is input to a pump controller 98 (reference numeral, A) instead of the ECU 26, and the fuel remaining in the first fuel storage unit 31 is determined by the pump controller 98A. The discharge flow rate of the fuel pump 14 is variably controlled by determining whether or not it is less than a predetermined amount and controlling the voltage applied to the fuel pump 14. In this case, a signal indicating whether or not the jet pump 22 is stopped (when the jet pump control valve (return passage control valve) 24 is closed) is input from the ECU 26 to the pump controller 98A.
According to the present embodiment, a part of the control capability of the ECU 26 can be shared by the pump controller 98A, and the burden of the control capability of the ECU 26 can be reduced.

[Example 8]
Embodiment 8 of the present invention will be described. FIG. 13 is a block diagram showing the fuel supply device.
As shown in FIG. 13, the present embodiment is a modification of the fourth embodiment (see FIG. 9). That is, the fuel pump 14 of this embodiment includes a pump controller 98B. This pump controller 98B is similar to that of the sixth embodiment (see FIG. 11), and is the first fuel storage unit 31 detected by the fuel remaining amount meter 96 (not shown in FIG. 13). By being controlled by the ECU 26 based on the remaining amount of fuel, the discharge flow rate of the fuel pump 14 is variably controlled in a plurality of stages.

  In addition, the control pressure chamber side recirculation passage 86 is a part of the fuel branched from between the vapor jet 54 (see FIG. 4) of the fuel pump 14 and the throttle 94 and flowing through the control pressure chamber recirculation passage 86. A fuel escape pipe 100 is provided to allow the part to escape into the first fuel storage unit 31. The fuel escape pipe 100 is provided with a throttle 102 that restricts the flow of fuel to escape into the first fuel storage unit 31 to a predetermined amount.

  A pressure relief valve (also referred to as “relief valve”) 104 is provided in the control pressure chamber 76 of the pressure regulator 60 (specifically, the case 68 (see FIG. 5)). The pressure relief valve 104 includes a relief passage 105 that penetrates the inside and outside of the case 68 on the control pressure chamber side, a valve member 106 that can open and close the relief passage 105, and a spring 107 that elastically presses the valve member 106 in the closing direction. It has. In the pressure relief valve 104, when the fuel pressure in the control pressure chamber 76 becomes higher than the elastic force of the spring 107, the valve member 106 is opened using the elasticity of the spring 107, and the fuel in the control pressure chamber 76 is released. The fuel pressure in the control pressure chamber 76 is lowered until it reaches a set value. When the fuel pressure in the control pressure chamber 76 reaches a set value, the valve member 106 is closed by the elasticity of the spring 107. The pressure relief valve 104 corresponds to a “pressure control valve” in this specification.

  The return passage 20 is branched from a fuel pressure regulating chamber side return passage 87 connected to the fuel pressure regulating chamber 75 of the pressure regulator 60 instead of the in-tank fuel supply passage 38. The return passage 20 is branched into two branch pipes 108 and 109 on the downstream side of the jet pump control valve 24. The jet pumps 22 are connected to the branch pipes 108 and 109, respectively. In the same manner as in the fourth embodiment (see FIG. 9), each jet pump 22 uses the flow of fuel flowing in the branch pipes 108 and 109 of the return passage 20 to form the second fuel storage section 32. The fuel is transferred into the first fuel storage unit 31. In this case, the two fuel storage units 32 in total may be the same fuel storage unit or different fuel storage units. As a different fuel storage part, the fuel storage part which divided the 2nd fuel storage part into two chambers corresponds, for example. In this embodiment, the fuel filter 16 is omitted.

FIG. 14 is a time chart showing opening and closing timings of the jet pump control valve and the fuel pressure variable control valve. Here, the variable control of the discharge flow rate of the fuel pump 14 by the pump controller 98B is ignored.
As shown in FIG. 14, the power source V is at a low voltage (battery voltage, starting voltage) from the start of engine startup to the completion of startup, but is high voltage (generator voltage, normal voltage) after engine startup. It is.
Further, the fuel pressure varying control valve 84A is in a closed state from the start of the engine until a lapse of a predetermined time after the completion of the start, and is thereafter opened. In the closed state of the fuel pressure variable control valve 84A, the fuel pressure supplied to the engine becomes a high fuel pressure (about 600 kPa). Further, in the open state of the fuel pressure variable control valve 84A, the fuel pressure supplied to the engine becomes a low fuel pressure (about 400 kPa).
Further, the jet pump control valve 24 is closed from the start of the engine to immediately after the start of the engine, and is then opened. Thus, the jet pump 22 stops when the jet pump control valve 24 is closed, and the jet pump 22 operates when the jet pump control valve 24 is open.

  According to the present embodiment, the pressure relief valve 104 for controlling the fuel pressure in the control pressure chamber 76 of the pressure regulator 60 to be equal to or lower than the set pressure is provided. Thereby, the fuel pressure in the control pressure chamber 76 of the pressure regulator 60 can be controlled to a set value or less. The pressure relief valve 104 is disposed on a fuel passage that communicates with the control pressure chamber 76 and has the same fuel pressure as the fuel pressure in the control pressure chamber 76, thereby reducing the fuel pressure in the control pressure chamber 76 to a set pressure or less. Can be controlled.

  Further, the fuel supply device 10 of this embodiment and the case where the jet pump control valve 24 is omitted (referred to as “comparative example”) are compared using an example of specific numerical values. In this embodiment and the comparative example, the fuel pressure supplied to the engine after engine startup is low (about 300 kPa), the discharge flow rate of the fuel pump 14 is 275 L / h, and is supplied to the engine when the engine is started. The fuel pressure is the same at a high fuel pressure (about 600 kPa). At this time, the discharge flow rate of the fuel pump 14 of the comparative example requires 110 L / h, whereas the discharge flow rate of the fuel pump 14 of the present embodiment requires 40 L / h. Therefore, the capacity of the fuel pump 14 required for the comparative example is 350 L / h at 300 kPa, whereas the capacity of the fuel pump 14 required for this embodiment is 275 L / h at 300 kPa. A pump can be reduced in size and power consumption can be reduced.

The fuel flowing out of the fuel outflow pipe 88 is 0 (zero) L / h when the fuel pressure varying control valve 84A is closed, and 10 L / h when the fuel pressure varying control valve 84A is opened. Become. For example, a normally open type electromagnetic on-off valve can be used as the fuel pressure varying control valve 84A.
The fuel flowing through the return passage 20 is 0 (zero) L / h because the return passage control valve 24 is closed when the engine is started, and the return passage control valve 24 is opened after the engine is started. Therefore, it is 50 L / h. Incidentally, in the comparative example, the fuel flowing through the return passage 20 when the engine was started was 70 L / h. As the return passage control valve 24, for example, a normally open type electromagnetic on-off valve can be used.
The fuel discharged from the fuel pressure regulating chamber 75 of the pressure regulator 60 is 5 L / h when the engine is started and after the engine is started. The fuel discharged from the fuel escape pipe 100 is 15 L / h when the engine is started and 10 L / h after the engine is started.

Therefore, when the engine is started, a total of 20 L / h of fuel, 5 L / h of fuel discharged from the fuel pressure regulating chamber 75 of the pressure regulator 60 and 15 L / h of fuel discharged from the fuel escape pipe 100, is obtained. Since the fuel is discharged into the tank, the fuel discharged into the fuel supply passage 39 outside the tank is 20 L / h out of 40 L / h of the discharge flow rate of the fuel pump 14.
Further, after the engine is started, 10 L / h of the fuel flowing out from the fuel pressure variable control valve 84 A, 50 L / h of the fuel flowing out from the return passage control valve 24, and the fuel regulator chamber 75 of the pressure regulator 60 are discharged. Since a total of 70 L / h of 5 L / h of fuel to be discharged and 10 L / h of fuel discharged from the fuel escape pipe 100 is discharged into the tank, the discharge flow rate of the fuel pump 14 is 275 L / h. Among them, the fuel discharged into the tank external fuel supply passage 39 is 200 L / h.

A fuel supply device according to a modification of the eighth embodiment of the present invention will be described. FIG. 15 is a block diagram showing the fuel supply device.
As shown in FIG. 15, the modified example eliminates the pressure relief valve 104 (see FIG. 13) in the eighth embodiment, and the pressure relief valve 104 ( The reference numeral A is attached.). Since the pressure relief valve 104A has the same configuration as that of the pressure relief valve 104, the same parts are denoted by the same reference numerals and the description thereof is omitted. The pressure relief valve 104A controls the fuel pressure in the fuel pressure regulating chamber 75 of the pressure regulator 60 to a set pressure or lower. The pressure relief valve 104A corresponds to a “pressure control valve” in this specification.

  According to this modified example, the pressure relief valve 104A for controlling the fuel pressure in the fuel pressure regulating chamber 75 of the pressure regulator 60 to a set pressure or less is provided. Thereby, the fuel pressure in the fuel pressure regulating chamber 75 of the pressure regulator 60 can be controlled to be equal to or lower than the set value. The pressure relief valve 104A communicates with the fuel pressure regulating chamber 75 and is disposed on a fuel passage that has the same fuel pressure as the fuel pressure within the fuel pressure regulating chamber 75, thereby setting the fuel pressure in the fuel pressure regulating chamber 75. It can be controlled below the pressure.

[Example 9]
Embodiment 9 of the present invention will be described. FIG. 16 is a block diagram showing the fuel supply device.
As shown in FIG. 16, the present embodiment is a modification of the eighth embodiment (see FIG. 13). That is, the fuel escape pipe 100 is provided with a jet pump 22 instead of the throttle 102. The jet pump 22 can transfer the fuel in the second fuel storage unit 32 into the first fuel storage unit 31 using the flow of fuel flowing in the fuel escape pipe 100. In this case, the three second fuel storage units 32 may be the same fuel storage unit or different fuel storage units. As a different fuel storage part, the fuel storage part which divided the 2nd fuel storage part into three chambers corresponds, for example.

[Example 10]
A tenth embodiment of the present invention will be described. FIG. 17 is a block diagram showing the fuel supply device.
As shown in FIG. 17, the present embodiment is a modification of the eighth embodiment (see FIG. 13). That is, the return passage 20 branched from the fuel pressure regulating chamber side return passage 87 connected to the fuel pressure regulating chamber 75 of the pressure regulator 60, and the jet pump control valve 24 and the jet pump 22 attached to the return passage 20 are omitted. is doing. Instead, the fuel outflow pipe 88 (see FIG. 13) of the pressure regulator 60 is a fuel outflow pipe / return passage (simply referred to as “return passage”) 112, and the fuel pressure variable control valve 84A (see FIG. 13). )) Is a fuel pressure variable and jet pump control valve (simply referred to as “control valve”) 114. A jet pump 22 is connected to the fuel outflow pipe / return passage 112. The jet pump 22 transfers the fuel in the second fuel storage unit 32 into the first fuel storage unit 31 using the flow of fuel flowing in the fuel outflow pipe / return passage 112. In this embodiment, the throttle 94, the fuel relief pipe 100, and the throttle 102 in the eighth embodiment (see FIG. 13) are omitted.

FIG. 18 is a time chart showing the opening and closing timing of the jet pump control valve 24. As shown in FIG. 18, the power source V is at a low voltage (battery voltage, starting voltage) from the start of engine start to the completion of start, but is high voltage (generator voltage, normal voltage) after engine start. It is.
In addition, the control valve 114 is closed from the start of engine startup until the lapse of a predetermined time after the completion of startup, and then opened. In the closed state of the control valve 114, the fuel pressure supplied to the engine becomes a high fuel pressure (about 600 kPa) and the jet pump 22 stops. When the fuel pressure variable control valve 84A is in the open state, the fuel pressure supplied to the engine becomes a low fuel pressure (about 400 kPa) and the jet pump 22 operates.

  Moreover, the fuel supply apparatus 10 of a present Example is compared using an example of a specific numerical value. In this embodiment, the fuel pressure supplied to the engine after engine startup is low (about 300 kPa), the discharge flow rate of the fuel pump 14 is 130 L / h, and the fuel pressure supplied to the engine at engine startup is high fuel pressure. (About 600 kPa), the discharge flow rate of the fuel pump 14 is 15 L / h. The capacity of the fuel pump 14 required for this embodiment is only 130 L / h at 300 kPa.

The fuel flowing through the return passage 112 is 0 (zero) L / h because the control valve 114 is closed when the engine is started, and 15 L / h because the control valve 114 is opened after the engine is started. h. The fuel discharged from the fuel pressure regulating chamber 75 of the pressure regulator 60 is 5 L / h when the engine is started and after the engine is started.
For this reason, when the engine is started, 5 L / h of the fuel discharged from the fuel pressure regulating chamber 75 of the pressure regulator 60 is discharged into the tank. Therefore, out of 15 L / h of the discharge flow rate of the fuel pump 14, The fuel discharged into the tank external fuel supply passage 39 is 10 L / h.
Further, after starting the engine, a total of 20 L / h of fuel, 15 L / h of the fuel flowing out from the control valve 114 and 5 L / h of the fuel discharged from the fuel pressure regulating chamber 75 of the pressure regulator 60, is placed in the tank. Since the fuel is discharged, the fuel discharged into the fuel supply passage 39 outside the tank is 110 L / h out of 130 L / h of the discharge flow rate of the fuel pump 14.

  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. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims. In addition, the technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and the achievement of one of these objects has technical utility.

It is a block diagram which shows the fuel supply apparatus concerning Example 1 of this invention. It is sectional drawing which shows a vertical fuel tank. It is sectional drawing which shows a reservoir tank built-in type fuel tank. It is sectional drawing which shows a fuel pump. It is sectional drawing which shows a pressure regulator. It is a diagram which shows the relationship between the discharge pressure and discharge flow volume of a fuel pump. It is a block diagram which shows the fuel supply apparatus concerning Example 2 of this invention. It is a block diagram which shows the fuel supply apparatus concerning Example 3 of this invention. It is a block diagram which shows the fuel supply apparatus concerning Example 4 of this invention. It is a block diagram which shows the fuel supply apparatus concerning Example 5 of this invention. It is a block diagram which shows the fuel supply apparatus concerning Example 6 of this invention. It is a block diagram which shows the fuel supply apparatus concerning Example 7 of this invention. It is a block diagram which shows the fuel supply apparatus concerning Example 8 of this invention. It is a time chart which shows the opening / closing timing of the control valve for jet pumps, and the control valve for fuel pressure change. It is a block diagram which shows the fuel supply apparatus concerning the example of a change of Example 8 of this invention. It is a block diagram which shows the fuel supply apparatus concerning Example 9 of this invention. It is a block diagram which shows the fuel supply apparatus concerning Example 10 of this invention. It is a time chart which shows the opening / closing timing of the control valve for jet pumps. It is a block diagram which shows the fuel supply apparatus concerning a prior art example. It is a block diagram which shows the fuel supply apparatus concerning the example of a change of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel supply apparatus 12 Fuel tank 14 Fuel pump 18 Fuel pressure variable apparatus 20 Return path 22 Jet pump 24 Jet pump control valve (return path control valve)
26 ECU (control device)
31 First Fuel Storage Unit 32 Second Fuel Storage Unit 45 Engine 59 Low Pressure Side Recirculation Passage 60 Pressure Regulator 62 Fuel Pressure Variable Control Valve (Low Pressure Side Recirculation Passage Control Valve)
75 Fuel pressure adjusting chamber 76 Control pressure chamber 82 Fuel pressure variable device 84 Fuel pressure variable control valve (control pressure chamber side return passage control valve)
84A Fuel pressure variable control valve (control valve for control pressure chamber side return passage)
87 Control pressure chamber side recirculation passage 90 Fuel pressure variable device 96 Fuel remaining amount meter (fuel remaining amount detecting device)
104 Pressure relief valve (pressure control valve)
104A pressure relief valve (pressure control valve)
114 Control valve for variable fuel pressure (control valve)

Claims (5)

A fuel tank having a first fuel storage section and a second fuel storage section;
A fuel pump provided in the first fuel storage unit;
A fuel pressure variable device configured to be capable of adjusting the fuel pressure supplied from the fuel pump to the engine in at least two stages;
A return passage for returning a part of the fuel discharged from the fuel pump into the first fuel storage unit;
A fuel supply device comprising: a jet pump that transfers fuel in the second fuel storage unit into the first fuel storage unit using a flow of fuel flowing in the return passage;
A return passage control valve for controlling the operation of the jet pump by opening and closing the return passage, and a control device for controlling the return passage control valve are provided, and a low voltage at a high fuel pressure by the fuel pressure variable device. The fuel supply device is characterized in that the control device is configured to stop the jet pump by closing the return passage control valve. The fuel supply device according to claim 1,
A fuel remaining amount detecting device for detecting a fuel remaining amount in the first fuel storage unit, the fuel remaining amount detected by the fuel remaining amount detecting device at a low fuel pressure and a normal voltage by the fuel pressure variable device. The fuel supply device according to claim 1, wherein the control device is configured to operate the jet pump by opening the return passage control valve when the value is equal to or less than a predetermined amount. The fuel supply device according to claim 1 or 2,
The fuel pressure variable device is configured to adjust the fuel pressure supplied to the engine to a high pressure, and the low pressure side pressure regulator configured to adjust the fuel pressure supplied to the engine to a low pressure. And a control valve for a low-pressure side recirculation passage that guides a part of the fuel discharged from the fuel pump to the low-pressure side pressure regulator and that opens and closes a low-pressure side recirculation passage that is controlled by a control device and recirculates into the fuel tank. With
The controller is configured to control the fuel pressure supplied to the engine by controlling the operation of the low-pressure side pressure regulator by opening and closing the low-pressure side reflux passage control valve. Fuel supply device. The fuel supply device according to claim 1 or 2,
The variable fuel pressure device has a fuel pressure control chamber and a control pressure chamber, each of which is supplied with fuel from the fuel pump and defined by a movable partition wall, and the pressure in the fuel pressure control chamber is set to a pressure in the control pressure chamber. And a pressure regulator that returns the fuel that has been adjusted and surplus to the inside of the fuel tank, a part of the fuel pressurized by the fuel pump is led to the control pressure chamber and controlled by the control device, and A control pressure chamber side recirculation passage control valve for opening and closing a control pressure chamber recirculation passage for recirculation in the fuel tank,
The control device is configured to adjust the fuel pressure supplied to the engine by adjusting the pressure of the control pressure chamber in at least two stages by opening and closing the control valve for the control pressure chamber side return passage. The fuel supply apparatus characterized by the above-mentioned. The fuel supply device according to claim 4,
A fuel supply device comprising a pressure control valve for controlling a fuel pressure in a fuel pressure adjusting chamber and / or a control pressure chamber of the pressure regulator to be equal to or lower than a set pressure.

Images