JP2014202101A - Fuel supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel supply system capable of effectively inhibiting a siphon phenomenon from greatly reducing the amount of fuel in a reservoir cup so as to reduce the startability of an internal combustion engine.SOLUTION: A fuel supply system includes: a reservoir cup 28 arranged in a fuel tank 21; a feed pump 22 arranged in the reservoir cup 28; a fuel supply passage P1 for guiding fuel discharged from the fuel pump 22 along a supply direction; a return passage P2 for recycling part of the fuel discharged from the feed pump 22 into the fuel tank 21; and a solenoid flow control valve 24 having an inflow port 24a for allowing the fuel passing through the return passage P2 to flow into the reservoir cup 28, and capable of controlling the amount of the fuel to flow into the reservoir cup 28. The inflow port 24a of the solenoid flow control valve 24 is arranged on the high liquid level side of the reservoir cup 28 within a liquid level variation range of the fuel reserved in the reservoir cup 28.

Description

  The present invention relates to a fuel supply system, and more particularly to a fuel supply system having a return passage for supplying fuel from a reservoir cup in a fuel tank by a fuel pump and returning surplus fuel into the fuel tank.

  2. Description of the Related Art In an internal combustion engine for a vehicle (hereinafter referred to as an engine), a fuel supply system that variably controls the flow rate of fuel supplied to the engine according to the operating state of the engine is frequently used.

  In such a fuel supply system, the fuel is pumped up from the reservoir cup in the fuel tank by the fuel pump, and the jet pump is operated by using the surplus fuel recirculated into the fuel tank, so that the fuel is put into the reservoir cup. There are many things to replenish.

  As such a fuel supply system, for example, a fuel pump and a pressure regulator are arranged inside a reservoir cup in a fuel tank, and a return passage extending from the fuel pump to the back pressure chamber of the pressure regulator is provided from the reservoir cup to the outside of the reservoir cup. It is known that a bypass passage that extends to the jet pump is configured to bypass the fuel pump (see, for example, Patent Document 1).

JP 2011-132843 A

  However, in the conventional fuel supply system as described above, it is necessary to use a plurality of types of fuel pumps in order to switch the pressure and flow rate of the fuel supplied to the internal combustion engine, resulting in a complicated configuration and high cost. There was a problem of becoming.

  Also, when stopping the engine operation, the so-called siphon phenomenon causes the fuel in the reservoir cup to flow out of the reservoir cup through the fuel pump and the return passage, and the amount of fuel in the reservoir cup is insufficient when starting the engine. There was a possibility. Note that the siphon phenomenon referred to here is a reservoir cup in which the fuel in the reservoir cup, which has a high liquid level when the fuel pump is stopped, moves over the peripheral wall of the reservoir cup and has a relatively low liquid level. It is a phenomenon that is pumped into the outside fuel.

  Of the two problems described above, for the former, for example, a fuel pump capable of changing the discharge capacity, and when the fuel consumption of the internal combustion engine is low, the fuel return from the fuel pump into the fuel tank is sufficiently allowed, It is also possible to simplify the system configuration and reduce costs by providing a solenoid valve with a function to limit the return of fuel to the fuel tank when fuel consumption is high or high fuel pressure is required. It is done.

  However, even in that case, the fuel in the reservoir cup may flow out of the reservoir cup from the fuel pump or solenoid valve due to the siphon phenomenon, and the amount of fuel in the reservoir cup may be less than the amount required when starting the engine. There is. Moreover, when unfiltered fuel flows into the pipe line from the solenoid valve due to the siphon phenomenon, there is a concern that a foreign matter biting failure of the solenoid valve may occur. Furthermore, when air enters from the solenoid valve and fuel leakage from the fuel pump to the jet pump occurs, there is a concern that the startability of the internal combustion engine may deteriorate.

  Therefore, the present invention provides a fuel supply system that can effectively suppress the fuel in the reservoir cup from greatly decreasing to the extent that the startability of the internal combustion engine is decreased due to the siphon phenomenon.

  In order to solve the above problems, a fuel supply system according to the present invention includes (1) a reservoir cup disposed in a fuel tank, a fuel pump disposed in the reservoir cup, and fuel discharged from the fuel pump. A fuel supply passage for guiding the fuel in the supply direction, a return passage for returning a part of the fuel discharged from the fuel pump into the fuel tank, and allowing the fuel to flow through the return passage into the reservoir cup And an inflow control mechanism capable of controlling an inflow amount of fuel into the reservoir cup, wherein the inflow control mechanism has the inflow port in the reservoir cup. It is arranged on the high liquid level side of the reservoir cup within the range of the liquid level fluctuation of the stored fuel.

  In this invention, when the liquid level in the reservoir cup is slightly lowered, the inflow port of the inflow control mechanism is exposed from the liquid level or is in a state where air can be sucked, and the high liquid level fuel in the reservoir cup is returned to the return passage. The siphon phenomenon that is pumped into the low-level fuel outside the reservoir cup through is quickly and accurately suppressed. Therefore, it is possible to effectively suppress the fuel in the reservoir cup from being greatly reduced to the extent that the startability of the internal combustion engine is reduced due to the siphon phenomenon. The liquid level fluctuation range here is a range from the lowest liquid level height near the inner bottom surface of the reservoir cup to the highest liquid level height near the upper end of the peripheral wall of the reservoir cup.

  In the fuel supply system of the present invention, (2) the inflow port of the inflow control mechanism may be disposed on the upper end side of the peripheral wall of the reservoir cup with respect to the height of the discharge port of the fuel pump.

  In this case, the inlet of the inflow control mechanism is located on the upper end side of the peripheral wall of the reservoir cup with respect to the height of the discharge port of the fuel pump. Therefore, the siphon phenomenon through the inflow control mechanism and the fuel pump is effectively suppressed.

  In the fuel supply system of the present invention, (3) the discharge port of the fuel pump is disposed at a position lower than the upper end of the peripheral wall of the reservoir cup, and the inflow port of the inflow control mechanism is provided with the fuel You may arrange | position in the position higher than the said discharge outlet of a pump.

  In this case, the siphon phenomenon through the inflow control mechanism and the fuel pump is effectively suppressed by arranging the inlet of the inflow control mechanism at a position higher than the discharge port of the fuel pump.

  In the fuel supply system of the present invention, (4) the discharge port of the fuel pump is disposed at a position higher than the upper end of the peripheral wall of the reservoir cup, and the inlet of the inflow control mechanism is connected to the reservoir. You may arrange | position in the height position of the upper end of the said surrounding wall of a cup.

  In this case, the siphon phenomenon through the inflow control mechanism and the fuel pump is effectively suppressed by arranging the inlet of the inflow control mechanism at the height position of the upper end of the peripheral wall of the reservoir cup.

  In the fuel supply system of the present invention, (5) the discharge port of the fuel pump and the inflow port of the inflow control mechanism may be arranged at the height position of the upper end of the peripheral wall of the reservoir cup, respectively. .

  In this case, since the discharge port of the fuel pump and the inlet of the inflow control mechanism are arranged at the height position of the upper end of the peripheral wall of the reservoir cup, both the siphon phenomenon through the fuel pump and the inflow control mechanism is effectively suppressed. Will be.

  In the fuel supply system of the present invention, (6) from the fuel pump side to the inflow control mechanism side so as to be located in an upstream return path section from the fuel pump to the inflow control mechanism in the return path. A one-way valve that allows fuel flow and restricts fuel flow from the inflow control mechanism side to the fuel pump side may be disposed.

  In this case, even if air enters the fuel passage on the inflow control mechanism side, air can be easily and reliably prevented from entering the fuel pump side and the fuel supply passage side from the one-way valve.

  In the fuel supply system of the present invention, (7) the inflow control mechanism is in a valve open state that allows inflow of fuel through the return passage into the reservoir cup and in the reservoir cup of fuel through the return passage. It may be configured to include an electromagnetic valve that can be switched to a closed state that restricts the inflow to the valve.

  With this configuration, the solenoid valve is opened when the fuel consumption is low, and the solenoid valve is closed when the fuel consumption is high. The variable control range of the supply amount can be easily expanded.

  According to the present invention, when the liquid level in the reservoir cup slightly decreases, the inflow port of the inflow control mechanism can suck in air, so that the fuel in the reservoir cup reduces the startability of the internal combustion engine due to the siphon phenomenon. Thus, it is possible to provide a fuel supply system that can effectively suppress a significant decrease to the extent of the reduction.

1 is a schematic overall configuration diagram of a fuel supply system according to a first embodiment of the present invention. It is a principal part block diagram of the fuel supply system which concerns on 1st Embodiment of this invention. It is a principal part block diagram of the fuel supply system which concerns on 2nd Embodiment of this invention. It is a principal part block diagram of the fuel supply system which concerns on 3rd Embodiment of this invention. It is a principal part block diagram of the fuel supply system which concerns on 4th Embodiment of this invention. It is a principal part block diagram of the fuel supply system which concerns on 5th Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
1 and 2 show a fuel supply system according to a first embodiment of the present invention, and show an embodiment in which the present invention is applied to a fuel supply system of an internal combustion engine.

  First, the configuration of the fuel supply system will be described.

  As shown in FIG. 1, the fuel supply system of the present embodiment includes a first fuel supply mechanism 20 that supplies low-pressure side fuel for port injection to an engine 10 (fuel consumption unit) that is a multi-cylinder internal combustion engine, A second fuel supply mechanism 30 that pressurizes the fuel supplied from the first fuel supply mechanism 20 to supply high-pressure side fuel for in-cylinder injection, and variably controls the supply pressure of low-pressure side fuel according to the operating state of the engine 10 And a variable fuel pressure mechanism 40.

  The engine 10 is a multi-cylinder internal combustion engine mounted on an automobile, for example, an in-line 4-cylinder 4-cycle gasoline engine. The engine 10 normally operates in a fuel consumption state in which rotational power is output from a crankshaft (not shown) while consuming fuel, for example, gasoline, in each cylinder 11. Further, the engine 10 can be operated in a fuel cut state in which the crankshaft is rotated while hardly consuming fuel temporarily during deceleration or engine braking, or can be operated with low fuel consumption during idle operation. It is like that.

  A piston 12 is housed in each cylinder 11 of the engine 10, a combustion chamber 13 is defined, and an intake valve 14 and an exhaust valve (not shown) are mounted so as to be opened and closed at predetermined timings. Further, the engine 10 is provided with a plurality of spark plugs 15 corresponding to the plurality of cylinders 11 so as to be exposed in the corresponding combustion chambers 13, respectively. A device, an electronically controlled throttle motor (not shown) that variably controls the throttle opening, and the like are provided.

  The first fuel supply mechanism 20 includes a fuel tank 21, a feed pump 22 (fuel pump), a relief valve 23, an electromagnetic flow control valve 24, a low pressure fuel pipe 25, a low pressure delivery pipe 26, and a plurality of port injection injectors 27. (Low pressure fuel injection valve), a reservoir cup 28 and a jet pump 29 are included.

  The fuel tank 21 has a predetermined volume in which a reservoir cup 28 is disposed on the inside thereof, and can be replenished with fuel from the outside. In this fuel tank 21, the fuel storage area in the range from the inner bottom surface 21 d to a predetermined maximum liquid level height is divided into a small volume area R 1 in the reservoir cup 28 and a large volume area R 2 outside the reservoir cup 28. Has been.

  The feed pump 22 is of a variable discharge capability (discharge pressure and discharge amount) type that can pump up the fuel in the fuel tank 21 and pressurize it to a predetermined feed fuel pressure or higher, and is constituted by a circumferential flow pump, for example. . Although not shown in detail, the feed pump 22 has an impeller for operating the pump and a built-in motor that drives the pump operating portion. Further, the feed pump 22 changes the discharge capacity per unit time by changing at least one of the rotational speed and rotational torque of the impeller for operating the pump in accordance with, for example, the drive voltage and load torque of the built-in motor. That is, the discharge pressure and the discharge amount can be changed. The feed pump 22 is provided with a coupling filter 22f in which a suction filter portion that captures foreign matter in the intake fuel and a fuel filter portion that captures foreign matter in the discharged fuel are coupled.

  The relief valve 23 opens when the pressure of the fuel discharged from the feed pump 22 into the low-pressure fuel pipe 25 rises to reach a preset upper limit pressure, and restricts the fuel pressure below the preset upper limit pressure. A pressure control valve having a safety valve function. The set upper limit pressure is a fuel pressure that is high enough to easily induce a fuel leak from the port injection injector 27, for example, when the fuel pressure exceeds the set upper limit pressure.

  As shown in FIG. 2, the relief valve 23 has a relief valve body 23a and a valve seat 23b for closing a fuel discharge port (not shown in detail) from the low-pressure fuel pipe 25 side, for example, and the relief valve body 23a is always connected. Although it has a valve spring 23c that biases in the valve closing direction, such a structure itself of the relief valve 23 can be any conventional relief valve structure that can be used to limit the fuel pressure.

  The electromagnetic flow control valve 24 is in an open state in which fuel passing through the low-pressure fuel pipe 25 (especially in a return passage P2 to be described later) flows into the reservoir cup 28 of the fuel tank 21, and in the low-pressure fuel pipe 25. This is an electromagnetic valve that can be switched to a closed valve state that restricts the inflow of fuel into the reservoir cup 28. The electromagnetic flow control valve 24 is in a non-excited state when the fuel consumption is smaller than a predetermined amount, such as during idling of the engine 10, so that excess fuel can be returned into the fuel tank 21. It has become.

  Specifically, as shown in FIG. 2, the electromagnetic flow control valve 24 includes a valve body 24v including a magnetic material at least in part, and holding the valve body 24v in a state of being movable in the axial direction and a low-pressure fuel pipe. And a holding cylinder portion 24b forming an inflow port 24a through which fuel from the 25th side can flow into the reservoir cup 28. Further, the electromagnetic flow control valve 24 includes an electromagnetic coil 24c capable of urging the valve body 24v in the holding cylinder portion 24b toward the one axial side that is the upper side in FIG. The valve body 24v has a valve seat 24s on which the valve body 24v can be seated when the body 24v is urged to one side in the axial direction by the electromagnetic coil 24c.

  The electromagnetic flow control valve 24 substantially prevents the flow of fuel from the low-pressure fuel pipe 25 into the reservoir cup 28 when the valve body 24v is seated on the valve seat 24s by exciting the electromagnetic coil 24c. The valve is closed. In addition, when the electromagnetic coil 24c is de-energized and the valve body 24v is disengaged from the valve seat 24s, the electromagnetic flow control valve 24 allows fuel to flow from the low-pressure fuel pipe 25 into the reservoir cup 28 through the inlet 24a. The valve is opened to allow The valve body 24v hits a part of the holding cylinder part 24b without closing the inlet 24a of the holding cylinder part 24b when the electromagnetic flow control valve 24 is opened.

  As described above, the electromagnetic flow control valve 24 has the inflow port 24 a that allows the fuel flowing through the low-pressure fuel pipe 25 to flow into the reservoir cup 28, and controls the amount of fuel flowing into the reservoir cup 28. A controllable inflow control mechanism is configured.

  The inflow port 24a of the electromagnetic flow control valve 24 is, for example, a height H2 of the discharge port 22a of the feed pump 22 on the high liquid level side of the reservoir cup 28 within the liquid level fluctuation range of the fuel stored in the reservoir cup 28. The upper end of the peripheral wall 28e of the reservoir cup 28 is disposed slightly on the height H1 (position in the height direction) side with respect to (the position in the height direction). The liquid level fluctuation range here is from the lowest liquid level height located in the vicinity of the inner bottom surface 28d of the reservoir cup 28 to the highest liquid level height located in the vicinity of the height H1 of the upper end of the peripheral wall 28e of the reservoir cup 28. And can be set in consideration of liquid level fluctuation, surface tension, and the like.

  In the present embodiment, the discharge port 22a of the feed pump 22 is disposed in the vicinity of the height H2 that is lower than the height H1 of the upper end of the peripheral wall 28e of the reservoir cup 28. Therefore, the inlet 24a of the electromagnetic flow control valve 24 is provided. Is disposed at a position higher than the discharge port 22 a of the feed pump 22. However, as long as the discharge port 22a of the feed pump 22 is close to the height H1 of the upper end of the peripheral wall 28e of the reservoir cup 28, the feed pump 22 may be disposed at a lower position than the discharge port 22a of the feed pump 22.

  The low-pressure fuel pipe 25 can supply the fuel supplied from the feed pump 22 to the delivery pipe 26 on the low-pressure side. The low-pressure fuel pipe 25 includes a supply pipe portion 25a that forms a fuel supply passage P1 from the feed pump 22 to the delivery pipe 26 on the low-pressure side, and a return pipe that forms a return passage P2 from the feed pump 22 into the fuel tank 21. Part 25b.

  Here, the fuel supply passage P1 can flow the fuel discharged from the feed pump 22 into the delivery pipe 26 on the low pressure side by guiding the fuel in the supply direction set in advance. The return passage P2 is directed so as to branch from the fuel supply passage P1 and return to the inner bottom side of the fuel tank 21, and return a part of the fuel discharged from the feed pump 22 to the fuel tank 21. It can be made to. Further, the return passage P2 forms a first return passage portion P2a that extends from the feed pump 22 to the outside of the reservoir cup 28 while being connected to the electromagnetic flow control valve 24, and an inflow port 24a that is branched from the first return passage portion P2a. And a second return passage portion P2b that opens from the electromagnetic flow control valve 24 into the reservoir cup 28.

  The delivery pipe 26 on the low-pressure side is made of metal that introduces the fuel pressurized by the feed pump 22 through the low-pressure fuel pipe 25 and stores a predetermined amount of fuel, and bends according to the pressure of the fuel. Thus, both the function of absorbing the pulsation of the fuel pressure and the function of accumulating the fuel pressure necessary for the port injection from the port injection injector 27 are provided.

  The plurality of port injection injectors 27 are provided in the intake branch pipe portions corresponding to the plurality of cylinders 11 of the engine 10, and the respective injection hole portions are exposed in the intake ports 11 a corresponding to the respective cylinders 11. Yes. The plurality of injectors 27 are connected to the low-pressure delivery pipe 26 and wired to a driver circuit (not shown) on the ECU 42 side so as to be opened by a port injection drive signal from the ECU 42. When the plurality of injectors 27 are sequentially driven by the port injection drive signal, the fuel accumulated and stored in the delivery pipe 26 is injected into the intake port 11a from any of the opened injectors 27. It has become.

  The reservoir cup 28 has a concave shape that opens the vertically upper side inside the fuel tank 21, and the peripheral wall 28 e extends upward to the height H 1 of the fuel tank 21 so as to surround the inner bottom surface 28 d thereof. It is formed continuously in the direction. The fuel tank 21 may be a vertical type or the like that is divided into a sub tank corresponding to the reservoir cup and a tank portion outside the fuel tank 21 depending on the shape of the bottom wall. In other words, the reservoir cup 28 may be constituted by a sub tank formed by making the bottom wall portion of the fuel tank 21 uneven. The feed pump 22 arranged in the reservoir cup 28 is supported on the inner bottom surface 28d of the reservoir cup 28 via the coupling filter 22f, but may be supported by the peripheral wall 28e.

  In the jet pump 29, a nozzle portion 25n provided at the tip of the return piping portion 25b of the low-pressure fuel piping 25 is inserted into a pump passage 28b that opens to the outer periphery of the bottom portion of the fuel tank 21 and extends to the upper side of the inner wall of the fuel tank 21. It is a thing. The jet pump 29 injects fuel, which is fed into the low-pressure fuel pipe 25 with a feed pressure, from the nozzle part 25n of the return pipe part 25b into the throttle part 28c of the pump passage 28b, so that the upstream side of the throttle part 28c. The fuel is energized so as to be drawn downstream, and flows into the reservoir cup 28. Further, the jet pump 29 is configured such that fuel can be introduced into the reservoir cup 28 by the amount of fuel consumption that is successively consumed by the engine 10.

  Here, the pump passage 28b formed in the reservoir cup 28 opens into the reservoir cup 28 at a position where the height H2 is slightly lower than the height H1 of the upper end of the peripheral wall 28e from the inner bottom surface 28d of the reservoir cup 28. . This height H2 is substantially the same height as the opening height of the discharge port 22a of the feed pump 22, for example.

  The second fuel supply mechanism 30 includes a plunger-type fuel pressurizing pump 31, an electromagnetic spill-type intake control valve 32, a high-pressure fuel pipe 35, a high-pressure delivery pipe 36, and a plurality of in-cylinder injectors 37 ( High pressure fuel injection valve).

  The fuel pressurization pump 31 reciprocates a plunger (not shown) to change the volume of the fuel pressurization chamber, thereby sucking the fuel pressurized by the feed pump 22 into the fuel pressurization chamber through the high-pressure fuel pipe 35. The intake fuel is pressurized while the intake control valve 32 is closed, and can be discharged at a high pressure that allows direct fuel injection in the cylinder.

  The suction control valve 32 is selectively excited so as to enable the fuel pressurization operation of the fuel pressurization pump 31 and opens during the volume increase period of the fuel pressurization chamber of the fuel pressurization pump 31. During the volume reduction period of the fuel pressurization chamber of the pressurization pump 31, the valve can be closed only for a necessary period corresponding to the discharge amount (discharge fuel flow rate). Further, the suction control valve 32 can keep its open state so that the fuel pressurizing operation of the fuel pressurizing pump 31 is disabled.

  The delivery pipe 36 on the high pressure side is made of a highly rigid metal that introduces and stores fuel pressurized to high pressure by the fuel pressurizing pump 31, and accumulates high pressure fuel necessary for direct fuel injection in the cylinder. Has the function of storing.

  The plurality of in-cylinder injectors 37 are each connected to a high-pressure delivery pipe 36 and wired to a driver circuit (not shown) on the ECU 42 side so as to be opened by an in-cylinder injection drive signal from the ECU 42. Yes. Each of these injectors 37 corresponds to the high-pressure fuel accumulated and stored in the delivery pipe 36 on the high-pressure side when the valve is opened according to the valve opening time ratio (duty ratio) for each predetermined time by the in-cylinder injection drive signal. The fuel is injected into the cylinder 11.

  The fuel pressurizing pump 31 is driven by rotational power from a crankshaft (not shown) of the engine 10. The electromagnetic spill type suction control valve 32 is, for example, a normally open type valve that is normally open when no power is supplied.

  The variable fuel pressure mechanism 40 includes a fuel pressure control circuit (indicated as FPC in FIG. 1) 41 that can control the system supply fuel pressure by controlling the operation of the feed pump 22 of the first fuel supply mechanism 20, and a fuel pressure control. The ECU 42 is configured to variably control the discharge capacity of the feed pump 22 via the circuit 41. The variable fuel pressure mechanism 40 exhibits a function of variably controlling the discharge capacity of the feed pump 22 based on the operation state of the vehicle and the engine 10 and the requested operation input from the driver.

  The fuel pressure control circuit 41 controls the drive voltage of the feed pump 22 in accordance with the required fuel pressure Pc from the ECU 42, thereby variably controlling the discharge capacity (discharge amount and discharge pressure) of the feed pump 22 to deliver the low-pressure side delivery. The fuel pressure in the pipe 26 can be made to follow the required fuel pressure Pc from the ECU 42. The required fuel pressure Pc from the ECU 42 is calculated by the ECU 42 based on the operation state of the vehicle and the engine 10 and the required operation input from the driver. The actual fuel pressure in the delivery pipe 26 on the low pressure side is detected by the fuel pressure sensor 65 on the low pressure side, and the detected information is taken into the ECU 42.

  The ECU 42 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a backup memory (for example, a nonvolatile memory or a RAM backed up by a battery). The input interface circuit and the output interface circuit are included.

  An ON / OFF signal of an ignition switch (not shown) is taken into an input interface circuit of the ECU 42, and sensor information from various sensor groups is taken through an input interface circuit including an A / D converter and the like. . The output interface circuit of the ECU 42 is wired to the port 27 and in-cylinder injectors 27 and 37 and the electromagnetic drive unit (not shown) of the intake control valve 32 via a driver circuit (not shown) and is connected to the fuel pressure. A control circuit 41, an electronic throttle motor, the ignition device described above, and the like are connected.

  The various sensor groups connected to the input interface circuit of the ECU 42 include, for example, an accelerator opening sensor 61, an air flow meter 62, a crank angle sensor 63, a water temperature sensor 64, and a low-pressure fuel pressure sensor 65. Sensors, throttle opening sensors, air-fuel ratio sensors, oxygen sensors, intake cam angle sensors, exhaust cam angle sensors, high pressure fuel pressure sensors, and the like can be included.

  The ECU 42 of the variable fuel pressure mechanism 40 can execute known electronic throttle control, fuel injection amount control, ignition timing control, fuel cut control, and the like by executing a control program stored in the ROM. For example, the ECU 42 calculates the basic injection amount required for each combustion based on the intake air amount detected by the air flow meter 62 and the engine speed detected by the crank angle sensor 63, and further the operating state of the engine 10. The fuel injection amount subjected to various corrections and air-fuel ratio feedback corrections according to the above is calculated. The variable fuel pressure mechanism 40 can drive to open the injectors 27 and 37 corresponding to the fuel injection time corresponding to the fuel injection amount.

  Further, the ECU 42 sets a target fuel pressure according to the operating state of the engine 10, for example, at a high temperature restart when the engine 10 is started in a state where the cooling water temperature of the engine 10 is higher than a predetermined temperature, The target fuel pressure is set to a specific high fuel pressure when returning from the cut state to the normal operation state where the fuel is consumed.

  On the other hand, for example, when the engine 10 is in a mode region where the engine 10 is exclusively in partial load operation, the ECU 42 sets a low target fuel pressure so that fuel vapor is not easily generated in the fuel supply path due to heat generated by the engine 10 in the mode region. It is supposed to be set. The drive voltage of the feed pump 22 when the target fuel pressure on the low pressure side is set is such that even if foreign matter passing through the coupling filter 22f is sucked into the feed pump 22, the feed pump 22 is operated for pump operation. It is possible to generate sufficient rotational torque so that the impeller is not locked.

  The ECU 42 responds to the target fuel pressure in accordance with the operating state of the engine 10, the acceleration request from the driver, the shift operation or other requested operation input, etc. at predetermined time intervals during the operation period of the engine 10 or under the ignition ON state. The set pressure value is output to the fuel pressure control circuit 41 as the required fuel pressure Pc.

  The fuel pressure control circuit 41 that inputs the required fuel pressure Pc from the ECU 42 sets the deviation between the fuel pressures so that the input required fuel pressure Pc and the actual fuel pressure in the delivery pipe 26 detected by the fuel pressure sensor 65 coincide with each other. Accordingly, the drive voltage of the feed pump 22 is controlled. Then, according to the change in the drive voltage from the fuel pressure control circuit 41, the rotational speed and rotational torque (of course, both speed and torque may be sufficient) of the impeller for operating the pump of the feed pump 22 change. As a result, the fuel pressure in the delivery pipe 26 on the low pressure side changes in a direction to follow the required fuel pressure Pc.

  The fuel pressure control circuit 41 is provided with a voltage detection unit that detects a terminal voltage of the built-in motor of the feed pump 22 and a current detection unit that detects a current flowing through the built-in motor of the feed pump 22. The fuel pressure control circuit 41 controls the voltage applied to the built-in motor of the feed pump 22 according to the deviation between the required fuel pressure Pc from the ECU 42 and the actual fuel pressure detected by the fuel pressure sensor 65, or for abnormality diagnosis. A diagnostic signal (Diag signal in FIG. 1) according to the operating state of the built-in motor of the feed pump 22 can be supplied to the ECU 42. The fuel pressure control circuit 41 is supplied with power from a battery, and an ECU 42 is communicably connected thereto. In addition, the fuel pressure control circuit 41 incorporates a switching element (not shown) for variably controlling the voltage applied to the built-in motor of the feed pump 22 or the energy supplied to the built-in motor of the feed pump 22.

  Next, the operation will be described.

  In the present embodiment configured as described above, the fuel in the reservoir cup 28 is pumped up by the feed pump 22 of the first fuel supply mechanism 20, and the fuel pressurized to the feed pressure is discharged from the discharge port 22a. The The fuel discharged from the feed pump 22 is supplied to the delivery pipe 26 on the low pressure side through the supply piping portion 25 a of the low pressure fuel pipe 25 and also to the second fuel supply mechanism 30.

  At this time, in the first fuel supply mechanism 20, the fuel pressurized to the feed pressure by the feed pump 22 is accumulated and stored in the delivery pipe 26 on the low-pressure side, and any one of the injectors 27 is driven to be opened. At that time, fuel is injected from the injector 27 into the corresponding intake port 11a.

  Further, in the second fuel supply mechanism 30, the intake control valve 32 is closed at an appropriate time by the ECU 42, so that the fuel pressurized to a high pressure by the plunger-type fuel pressurization pump 31 is delivered to the high-pressure side delivery pipe. A necessary amount is introduced into 36, and the high fuel pressure in the delivery pipe 36 on the high pressure side is controlled to a predetermined value. When one of the injectors 37 is driven to open and opens, high-pressure fuel is directly injected from the injector 37 into the corresponding cylinder 11.

  Further, when the fuel consumption is smaller than a predetermined amount, such as when the engine 10 is idling, the electromagnetic flow control valve 24 is brought into a non-excited / open state, and the fuel discharged from the feed pump 22 is compared. A large amount (high ratio) of excess fuel is supplied to the jet pump 29 side through the return pipe portion 25 b of the low-pressure fuel pipe 25, and also flows back into the fuel tank 21 through the electromagnetic flow control valve 24. Is done.

  In this state, the amount of fuel flowing into the fuel tank 21 through the electromagnetic flow control valve 24 increases, and the amount of fuel pumped into the reservoir cup 28 by the jet pump 29 decreases. Therefore, the amount of fuel replenished into the reservoir cup 28 by the jet pump 29 when the fuel consumption of the engine 10 is low can be suppressed to a smaller amount than the relatively small amount of fuel discharged from the feed pump 22.

  On the other hand, when the fuel consumption is large, such as during high-load operation of the engine 10, the electromagnetic flow control valve 24 is excited and closed, and a low ratio of the fuel discharged from the feed pump 22. The surplus fuel is in a recirculation state in which only the jet pump 29 is supplied. Therefore, the amount of fuel replenished into the reservoir cup 28 by the jet pump 29 when the fuel consumption of the engine 10 is high increases sufficiently according to the relatively large amount of fuel discharged from the feed pump 22.

  In this way, during operation of the engine 10, the fuel is pumped up by the feed pump 22 in the reservoir cup 28 according to the operating state required for the engine 10, while the electromagnetic flow control valve 24 and the jet pump 29. As a result, the fuel flows into the reservoir cup 28. Therefore, the fuel level L1 in the reservoir cup 28 is maintained near the height H1 of the upper end of the peripheral wall 28e of the reservoir cup 28.

  When the engine 10 is stopped, the operation of the feed pump 22 is stopped, the fuel supply to the engine 10 is stopped, the excitation state due to the energization of the electromagnetic flow control valve 24 is released, and the electromagnetic flow control valve 24 is opened. It becomes a valve state.

  When the engine 10 is stopped, the fuel in the return passage P2 is still moving in the recirculation direction, so the fuel on the high liquid level L1 in the reservoir cup 28 passes through the return passage P2 and the low liquid level L2 outside the reservoir cup 28. The siphon phenomenon that is pumped into the fuel can occur.

  However, when the siphon phenomenon occurs and the fuel level L1 of the fuel in the reservoir cup 28 slightly decreases, the inlet 24a of the electromagnetic flow control valve 24 is exposed from the liquid level L1 or air can be sucked. Therefore, the siphon phenomenon in which the fuel in the reservoir cup 28 is pumped out of the reservoir cup 28 is quickly and accurately suppressed. As a result, it is effectively suppressed that the fuel in the reservoir cup 28 is greatly reduced by the siphon phenomenon to the extent that the startability of the engine 10 is reduced, and the amount of fuel in the reservoir cup 28 becomes insufficient when the engine 10 is started. This can be prevented.

  In particular, in the present embodiment, the inlet 24a of the electromagnetic flow control valve 24 is located on the upper end side of the peripheral wall 28e of the reservoir cup 28 above the discharge port 22a of the feed pump 22, so the feed pump 22 and the electromagnetic flow control valve The siphon phenomenon through 24 is effectively suppressed.

  Moreover, unfiltered fuel flows into the electromagnetic valve until air enters the electromagnetic flow control valve 24, but the inner side of the electromagnetic flow control valve 24 arranged near the height H1 of the upper end of the peripheral wall 28e of the reservoir cup 28. Therefore, it is possible to prevent the unfiltered fuel from continuing to flow in very early. Therefore, occurrence of a foreign matter biting failure in the electromagnetic flow control valve 24 due to the unfiltered fuel flowing into the low-pressure fuel pipe 25 from the electromagnetic flow control valve 24 is effectively suppressed.

  In this embodiment, the electromagnetic flow control valve 24 is opened when the fuel consumption of the engine 10 is low, and the electromagnetic flow control valve 24 is closed when the fuel consumption of the engine 10 is high. While suppressing the variable control range of the capacity, the variable control range of the fuel supply pressure and the fuel supply amount as the fuel supply system can be easily and sufficiently expanded.

  As described above, in this embodiment, when the liquid level in the reservoir cup 28 is slightly lowered, the inflow port 24a of the electromagnetic flow control valve 24 can suck air, so that the electromagnetic flow control is performed when the engine 10 is stopped. Even if the valve 24 opens, it is possible to prevent the fuel in the reservoir cup 28 from flowing out of the reservoir cup 28 due to the siphon phenomenon. Therefore, it is possible to provide a fuel supply system that can effectively suppress the fuel in the reservoir cup 28 from greatly decreasing to a degree that reduces the startability of the engine 10 due to the siphon phenomenon.

(Second Embodiment)
FIG. 3 shows a main configuration of a fuel supply system according to the second embodiment of the present invention.

  Each embodiment described below has an overall configuration similar to that of the above-described first embodiment, and therefore the same or similar configuration as that of the first embodiment is represented by the corresponding components shown in FIG. 1 and FIG. Hereinafter, differences from the first embodiment will be described.

  In the present embodiment, the flow of fuel from the feed pump 22 side to the electromagnetic flow control valve 24 side so as to be positioned in the upstream return passage section P2u from the feed pump 22 to the electromagnetic flow control valve 24 in the return passage P2. And a check valve 51 (one-way valve) that restricts the flow of fuel from the electromagnetic flow control valve 24 side to the feed pump 22 side is disposed. This check valve 51 can be opened when the feed pump 22 side becomes high by, for example, a very small predetermined front-rear differential pressure, but even if air is sucked from the inlet 24a of the electromagnetic flow control valve 24, the check valve 51 The valve can be kept closed to prevent air from entering the fuel supply passage P1 on the feed pump 22 side from the check valve 51.

  Specifically, the check valve 51 includes, for example, a spherical valve body 51v, a conical valve seat 51s, and a valve spring 51c, and the spherical valve body 51v is biased to the valve seat 51s by the valve spring 51c. ing. Other configurations are the same as those of the first embodiment.

  Also in the present embodiment, if the liquid level L1 in the reservoir cup 28 is slightly lowered, the inlet 24a of the electromagnetic flow control valve 24 is exposed or air can be sucked in. Therefore, the fuel in the reservoir cup 28 is caused by the siphon phenomenon. Can be prevented from flowing out of the reservoir cup 28, and the same effect as in the first embodiment can be obtained.

  Further, in the present embodiment, even if air enters the second return passage portion P2b on the electromagnetic flow control valve 24 side, air enters the feed pump 22 side or the fuel supply passage P1 side from the electromagnetic flow control valve 24. Can be easily and reliably prevented. Therefore, it is possible to prevent the startability of the engine 10 from deteriorating due to fuel loss in the return pipe portion 25b from the feed pump 22 to the jet pump 29.

(Third embodiment)
FIG. 4 shows a main configuration of a fuel supply system according to the third embodiment of the present invention.

  In the present embodiment, the discharge port 22a of the feed pump 22 is disposed at a height H3 (position in the height direction) higher than the height H1 of the upper end of the peripheral wall 28e of the reservoir cup 28. The inflow port 24a of the electromagnetic flow control valve 24 has a height H1 of the upper end of the peripheral wall 28e of the reservoir cup 28 on the high liquid level side within the liquid level fluctuation range of the fuel stored in the reservoir cup 28, or It is located very close to it.

  Also in the present embodiment, if the liquid level L1 in the reservoir cup 28 is slightly lowered, the inlet 24a of the electromagnetic flow control valve 24 is exposed or air can be sucked in. Therefore, the fuel in the reservoir cup 28 is caused by the siphon phenomenon. Can be prevented from flowing out of the reservoir cup 28, and the same effect as in the first embodiment can be obtained.

  Furthermore, in the present embodiment, the inlet 24a of the electromagnetic flow control valve 24 is disposed at the height H1 at the upper end of the peripheral wall 28e of the reservoir cup 28, so that fuel is supplied to the outside of the reservoir cup 28 through the electromagnetic flow control valve 24. The siphon phenomenon of flowing out and the siphon phenomenon of flowing fuel out of the reservoir cup 28 through the feed pump 22 are effectively suppressed.

(Fourth embodiment)
FIG. 5 shows a main configuration of a fuel supply system according to the fourth embodiment of the present invention.

  In the present embodiment, the discharge port 22a of the feed pump 22 and the inflow port 24a of the electromagnetic flow control valve 24 are reservoirs that are on the high liquid level side within the liquid level fluctuation range of the fuel stored in the reservoir cup 28, respectively. The cup 28 is disposed at the height H1 of the upper end of the peripheral wall 28e.

  Therefore, also in the present embodiment, when the liquid level L1 in the reservoir cup 28 is slightly lowered, the inlet 24a of the electromagnetic flow control valve 24 is exposed or air can be sucked, and the siphon phenomenon causes the inside of the reservoir cup 28 to be inhaled. The fuel can be prevented from flowing out of the reservoir cup 28, and the same effect as in the first embodiment can be obtained.

  Further, in the present embodiment, the discharge port 22a of the feed pump 22 and the inlet 24a of the electromagnetic flow control valve 24 are disposed at the height H1 of the upper end of the peripheral wall 28e of the reservoir cup 28, so that the feed pump 22 and the electromagnetic flow control The siphon phenomenon through the valve 24 is more effectively suppressed.

(Fifth embodiment)
FIG. 6 shows a main configuration of a fuel supply system according to the fifth embodiment of the present invention.

  In each of the above-described embodiments, the inlet 24a of the electromagnetic flow control valve 24 is disposed at the lower end of the electromagnetic flow control valve 24, that is, the downstream end of the second return passage portion P2b. As shown in FIG. 6, the inflow port of the flow control valve is not a downstream end of the second return passage portion P2b, but a lateral hole-like outflow port through which fuel and air can be passed in the middle of the second return passage portion P2b. 24a may be formed. Moreover, as shown in FIG. 6, the some inflow port 24a may be formed in the same or different height position.

  In this case, the height position of the inlet referred to in the present invention is the center height of the horizontal hole-shaped inlet 24a that is located on the uppermost side and contributes to the suppression of the siphon phenomenon due to the introduction of air. Will have a function of making the position of the fuel flowing into the reservoir cup 28 into the liquid away from the liquid level L1. Therefore, also in this embodiment, the same effect as that of the first embodiment can be obtained.

  In each of the above-described embodiments, the electromagnetic flow control is performed as an inflow control mechanism that allows the fuel to flow into the reservoir cup 28 through the return path P2 and can control the amount of fuel flowing into the reservoir cup 28. Although the valve 24 is provided, the inflow control mechanism according to the present invention is not limited to an electromagnetic valve or a flow control valve.

  Further, the inflow control mechanism may be other than a valve, for example, a jet pump that pumps fuel upward by using fuel flowing down. In that case, the return passage P2 may be opened toward the inside of the jet pump, and a pipe extending from the jet pump to the fuel outside the reservoir cup 28 may be a pipe for pumping up the fuel. Although the inflow control mechanism referred to in the present invention may be composed of a branch pipe with a throttle hole instead of the electromagnetic flow control valve 24, fuel leakage always occurs, so that the flow control function is enhanced. Is desirable.

  Further, in FIGS. 1 to 5, a supply pipe portion 25a of the low-pressure fuel pipe 25 that forms the fuel supply path P1 to the delivery pipe 26 on the low-pressure side, and a return path P2 from the feed pump 22 to the fuel tank 21 are provided. The return pipe portion 25b of the low-pressure fuel pipe 25 to be formed is illustrated in a pipe shape. However, it goes without saying that the supply piping portion 25a and the return piping portion 25b may be formed integrally with the reservoir cup 28, its storage container, or the like.

  Further, in each of the above-described embodiments, the electromagnetic flow control valve 24 may be closed in a non-energized state when the pump is not operated, thereby preventing inflow of unfiltered fuel from the electromagnetic flow control valve 24. It is also possible. However, the condition for returning the surplus fuel by opening the solenoid valve occurs frequently even when the fuel consumption of the engine 10 is small. Therefore, in the setting of energization to open the valve, power consumption increases. End up.

  The fuel supply system of the present invention can also be applied to a case where a liquid serving as the fuel is supplied to a fuel consumption unit other than the internal combustion engine.

  As described above, the fuel supply system according to the present invention allows the inflow port of the inflow control mechanism to suck in air when the liquid level in the reservoir cup is slightly lowered. It is possible to provide a fuel supply system that can effectively suppress a significant decrease in the startability of the internal combustion engine due to the phenomenon. The present invention as described above is useful for all fuel supply systems having a return passage for supplying fuel from a reservoir cup in a fuel tank by a fuel pump and returning surplus fuel into the fuel tank.

DESCRIPTION OF SYMBOLS 10 ... Engine (internal combustion engine), 11 ... Cylinder, 11a ... Intake port, 20 ... 1st fuel supply mechanism, 21 ... Fuel tank, 22 ... Feed pump (fuel pump), 22a ... Discharge port, 23 ... Relief valve, 24 ... Electromagnetic flow control valve (inflow control mechanism), 24a ... inlet, 25 ... low pressure fuel piping, 25a ... supply piping, 25b ... return piping, 25n ... nozzle, 26 ... delivery pipe (low pressure delivery pipe) , 27 ... injectors (port injectors, low pressure fuel injection valves), 28 ... reservoir cup, 28b ... pump passage, 28d ... inner bottom surface, 28e ... peripheral wall, 29 ... jet pump, 30 ... second fuel supply mechanism, 31 ... fuel pressurizing pump, 32 ... suction control valve, 35 ... high-pressure fuel pipe, 36 ... delivery pipe (high-pressure side delivery pipe), 37 ... in Injector (injector for in-cylinder injection, high-pressure fuel injection valve), 40 ... fuel pressure variable mechanism, 41 ... fuel pressure control circuit, 42 ... ECU (electronic control unit), 51 ... check valve (one-way valve), H1 ... height (Position of upper end of reservoir cup, position in height direction), H2 ... Height (height of discharge port, position in height direction), H3 ... Height (height of discharge port, position in height direction) , L1 ... Liquid level (the liquid level in the reservoir cup, high liquid level), L2 ... Liquid level (the liquid level outside the reservoir cup, low liquid level), P1 ... Fuel supply passage, P2 ... Return passage, P2a ... First Return passage part, P2b ... second return passage part, P2u ... upstream return passage section, R1 ... small volume area, R2 ... large volume area

Claims (7)

A reservoir cup disposed in the fuel tank, a fuel pump disposed in the reservoir cup, a fuel supply passage for guiding fuel discharged from the fuel pump in a supply direction, and fuel discharged from the fuel pump A return passage that recirculates a portion of the fuel into the fuel tank, and an inflow port that allows inflow of fuel through the return passage into the reservoir cup and control of the amount of fuel flowing into the reservoir cup An inflow control mechanism, and a fuel supply system comprising:
The fuel supply system, wherein the inflow port of the inflow control mechanism is disposed on a high liquid level side of the reservoir cup within a liquid level fluctuation range of fuel stored in the reservoir cup.   2. The fuel supply system according to claim 1, wherein the inflow port of the inflow control mechanism is disposed on an upper end side of a peripheral wall of the reservoir cup with respect to a height of a discharge port of the fuel pump. The discharge port of the fuel pump is disposed at a position lower than the upper end of the peripheral wall of the reservoir cup;
The fuel supply system according to claim 2, wherein the inflow port of the inflow control mechanism is disposed at a position higher than the discharge port of the fuel pump. The discharge port of the fuel pump is disposed at a position higher than the upper end of the peripheral wall of the reservoir cup;
The fuel supply system according to claim 2, wherein the inflow port of the inflow control mechanism is disposed at a height position of an upper end of the peripheral wall of the reservoir cup.   2. The fuel supply system according to claim 1, wherein the discharge port of the fuel pump and the inflow port of the inflow control mechanism are respectively disposed at a height position of an upper end of the peripheral wall of the reservoir cup. .   The flow of fuel from the fuel pump side to the inflow control mechanism side is allowed so as to be located in the upstream return path section from the fuel pump to the inflow control mechanism in the return path, and the inflow control mechanism side The fuel supply system according to any one of claims 1 to 5, wherein a one-way valve for restricting a flow of fuel from the fuel to the fuel pump side is disposed.   The inflow control mechanism can be switched between a valve open state that allows inflow of fuel through the return passage into the reservoir cup and a valve closed state that restricts inflow of fuel through the return passage into the reservoir cup. The fuel supply system according to any one of claims 1 to 6, wherein the fuel supply system includes an electromagnetic valve.

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