JP5083169B2 - Fuel supply system - Google Patents

Description

  The present invention relates to a fuel supply system having a metering valve that opens and closes a suction passage in accordance with a reciprocating movement of a plunger and adjusts a suction amount of fuel into a pump chamber.

  As this type of fuel supply system, a fuel supply system having an integrated metering valve in which a needle portion and a valve portion are integrally formed is known (see, for example, Patent Document 1). Incidentally, the plunger reciprocates in the axial direction based on the rotational movement of the crankshaft of the internal combustion engine, and the metering valve is energized in the valve closing direction and a drive solenoid for driving in the valve opening direction. A biasing spring is provided to close the metering valve when the drive solenoid is energized, while the metering valve opens when the drive solenoid is not energized.

  As is well known, the maximum fuel supply amount is realized by opening the metering valve when the plunger reaches the top dead center and closing the metering valve when the plunger reaches the bottom dead center. . However, particularly when starting the engine, it is difficult to accurately detect the position of the crankshaft of the internal combustion engine, and hence the position of the plunger, so that the metering valve is opened when the plunger reaches top dead center, and It is difficult to close the metering valve when the plunger reaches bottom dead center. Therefore, in the fuel supply system having the integrated metering valve, it is difficult to realize the maximum fuel supply amount.

  On the other hand, a fuel supply system having a separate metering valve in which a needle portion and a valve portion are configured separately as in the technique described in Patent Document 2, for example, has been proposed.

In the fuel supply system having the separate metering valve, when the drive solenoid is energized and the needle portion is pulled up, the valve portion reciprocates according to the pressure difference between the fuel inside and outside the pump chamber. Specifically, in the pressurization stroke in which the plunger moves from the bottom dead center to the top dead center, the fuel pressure in the pump chamber becomes higher than the fuel pressure outside the pump chamber. When the valve is pulled up, the valve part closes automatically (self-closing). On the other hand, in the suction stroke in which the plunger moves from the top dead center to the bottom dead center, the fuel pressure in the pump chamber is lower than the fuel pressure outside the pump chamber. The valve part opens automatically (self-opening). As described above, in the fuel supply system having the separate metering valve, the position of the crankshaft of the internal combustion engine and the position of the plunger can be accurately detected by energizing the drive solenoid and pulling up the needle portion. If the plunger reaches the top dead center, the metering valve opens automatically, and when the plunger reaches the bottom dead center, the metering valve closes automatically. Can be realized.
JP 2003-322048 A JP 2007-138981 A

  However, in the fuel supply system having the separate metering valve, it may take a long time (for example, 1 second) to energize the drive solenoid and lift the needle portion. If the energization time for the drive solenoid is long, the amount of heat generated by the drive solenoid increases, so that the drive solenoid itself may be melted and the fuel supply system may fail.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel supply system capable of protecting a drive solenoid while achieving the maximum fuel supply amount. is there.

In order to achieve such an object, according to the first aspect of the present invention, the pump chamber having the suction passage and the supply passage and the reciprocating motion based on the rotational motion of the crankshaft of the internal combustion engine are used to move the suction passage into the pump chamber. A pump that sucks in the fuel, pressurizes the sucked fuel, and supplies the pressurized fuel to the outside of the pump chamber from the supply passage, and opens and closes the suction passage according to the reciprocating motion of the plunger, A fuel pump having a metering valve that adjusts the amount of fuel sucked into the room, and a fuel supply system including a control device that controls the fuel pump, the fuel pump being connected to a supply passage of the fuel pump, A delivery pipe for storing the supplied fuel; and a fuel pressure sensor for detecting an actual fuel pressure that is a pressure of the fuel stored in the delivery pipe. The metering valve, the valve portion and a valve portion for opening and closing the suction passage by reciprocating in accordance with the pressure difference between the pump chamber out of the fuel, while being constituted by a separate body from the said valve portion A needle part that regulates a range in which the needle part reciprocates, a biasing means that biases the needle part in a valve opening direction of the valve part, and a drive solenoid that drives the needle part in a valve closing direction of the valve part; And the control device controls energization in an energization mode of either an always energizing mode in which the energization to the drive solenoid is always energized or an emergency energization mode in which the energization to the drive solenoid is not always energized. a power supply controller which includes a timer unit for measuring the power supply controller is always energized mode duration is the time that energization control continues with always energized control mode, the power supply controller, said meter On the basis that it is determined that the always energized mode continuation time measured has exceeded the set determination time to protect the driving solenoid by parts, but switching from always energized mode to the emergency power mode, the Even if it is not determined that the continuous energization mode duration time measured by the time measuring unit has passed the determination time, it is determined that the difference between the actual fuel pressure detected by the fuel pressure sensor and the target fuel pressure is smaller than a predetermined determination fuel pressure. Based on this, it was decided to switch from the always energized mode to the emergency energized mode .

In such a configuration as a fuel supply system, first, the continuous current mode continuation time is measured by the timer unit. Then, the energization control unit switches from the always energized mode to the emergency energized mode based on the determination that the continuous energization mode duration measured by the timing unit has passed a predetermined determination time. As a result, the energization of the drive solenoid is always continued until the predetermined determination time elapses, so that the maximum fuel supply amount can be achieved. Since energization to the solenoid is no longer continued, the drive solenoid is protected. Thus, according to the above configuration, the drive solenoid can be protected while achieving the maximum fuel supply amount.
In the above configuration as the fuel supply system, a value that can be considered that the actual fuel pressure substantially matches the target fuel pressure can be adopted as the determination fuel pressure. When such a value is adopted, when the actual fuel pressure substantially coincides with the target fuel pressure, the emergency energization mode is switched, so that the occurrence of the actual fuel pressure exceeding the target fuel pressure (overshoot) can be reduced. .

In the configuration according to claim 1, in the invention according to claim 2, the energization control unit is configured on the condition that the target fuel pressure is larger than the actual fuel pressure when the ignition switch is turned on. The energization control in the normal energization mode is started, and the energization control in the emergency energization mode is started when the condition is not satisfied at the time when the ignition switch is turned on .

  In the configuration described in claim 1 or 2, the invention further includes a crank angle sensor that detects the position of the crankshaft of the internal combustion engine as in the invention described in claim 3, When energization control is performed in the hour energization mode, it is desirable to energize the drive solenoid based on the crank angle detected by the crank angle sensor.

  Hereinafter, an embodiment of a fuel supply system according to the present invention will be described with reference to FIGS. First, the configuration and function of the fuel supply system 1 will be described with reference to FIGS. FIG. 1 is a block diagram showing an example of the overall configuration of the fuel supply system 1 of the present embodiment, and FIG. 2 is a block diagram showing an example of the configuration of the metering valve 40 of the fuel supply system 1. It is.

  The fuel supply system 1 is configured as a so-called direct injection gasoline supply system that directly injects fuel into a cylinder of an internal combustion engine such as a gasoline engine.

  As shown in FIG. 1, the fuel supply system 1 includes a low-pressure fuel pump 2, a high-pressure fuel pump 3, a delivery pipe 4, a fuel injection valve 5, a control device 60, and the like.

  Among these, the low-pressure fuel pump 2 is constituted by a known electric pump. The low pressure fuel pump 2 pumps up the low pressure fuel stored in the fuel tank 6 and supplies it to the high pressure fuel pump 3.

  The high-pressure fuel pump 3 is a so-called plunger pump, and supplies the fuel supplied from the low-pressure fuel pump 2 to the delivery pipe 4 after being pressurized in the pump chamber 18. Specifically, the high-pressure fuel pump 3 includes a pump chamber 18 having a suction passage 18a for sucking low-pressure fuel supplied from the low-pressure fuel pump 2 and a supply passage 18b for supplying high-pressure fuel to the delivery pipe 4; By reciprocating on the basis of the rotational movement of the crankshaft of the internal combustion engine, the fuel is sucked into the pump chamber 18 from the suction passage 18a, the pressurized fuel is sucked, and the pump from the pressurized fuel supply passage 18b is pumped. And a plunger 11 for supplying to the outside of the chamber 18. Incidentally, the plunger 11 is driven by the rotational motion of the cam 16 provided on the cam shaft 16a for the pump of the internal combustion engine, and the cam shaft 16a for the internal combustion engine pumps according to the rotational motion of the crank shaft of the internal combustion engine. Rotating motion. In this way, the plunger 11 reciprocates based on the rotational motion of the crankshaft of the internal combustion engine.

  Further, the high-pressure fuel pump 3 includes a metering valve 40 that opens and closes the suction passage 18 a in accordance with the reciprocating motion of the plunger 11 and adjusts the amount of fuel sucked into the pump chamber 18. The configuration and operation of the metering valve 40 will be described later with reference to FIG. The high-pressure fuel pump 3 corresponds to the fuel pump described in the claims.

  The high pressure fuel pump 3 includes a discharge valve 20 and a relief valve 30. The discharge valve 20 opens when the pressure of the fuel pressurized in the pump chamber 18 exceeds a predetermined pressure (for example, “60 [kPa]), and supplies the high-pressure fuel to the delivery pipe 4. The relief valve 30 opens when the pressure on the downstream side of the high-pressure fuel pump 3 exceeds an abnormal pressure (for example, “15.3 [MPa]), and returns the fuel on the downstream side to the pump chamber 18 side. It is a valve for.

  The delivery pipe 4 accumulates high-pressure fuel whose pressure has been increased by the high-pressure fuel pump 3, and one fuel injection valve 5 is connected to each cylinder of the internal combustion engine. Incidentally, the fuel injection valve 5 injects high-pressure fuel supplied from the delivery pipe 4 into the combustion chamber of each cylinder.

  An ignition switch (hereinafter simply referred to as an IG switch) 51 is a known switch for instructing start of an internal combustion engine (not shown), and is connected to a control device 60 described later. When the IG switch 51 is manually operated by the user, the IG switch 51 transmits a signal indicating that to the control device 60. Upon receiving this signal, the control device 60 starts the internal combustion engine.

  The fuel pressure sensor 52 is a known pressure sensor using, for example, a piezoelectric element, and is attached to the delivery pipe 4 and connected to the control device 60. When the fuel pressure sensor 52 detects the pressure of the fuel stored in the delivery pipe 4 (hereinafter referred to as the actual fuel pressure) and detects the actual fuel pressure in the delivery pipe 4, the detected fuel pressure is sent to the control device 60. Output.

  The crank angle sensor 53 is a known rotation detection device configured by using, for example, an MRE (magnetoresistive element). A crankshaft of the internal combustion engine is provided with a timing rotor having a plurality of teeth, and a crank angle sensor 53 detects the crank angle based on a change in magnetic vector caused by the rotation of the timing rotor. Then, the rotational speed of the internal combustion engine is calculated. The crank angle sensor 53 is connected to the control device 60 and outputs the detected crank angle to the control device 60.

  Hereinafter, the metering valve 40 will be described with reference to FIG. As described above, the metering valve 40 opens and closes the suction passage 18 a according to the reciprocating motion of the plunger 11 to adjust the amount of low-pressure fuel sucked into the pump chamber 18. As shown in FIG. 2, the metering valve 40 includes a valve portion 41, a needle portion 42, a biasing spring 43, a driving solenoid 44, and the like, and the valve portion 41 and the needle portion 42 have a separate structure. It is a so-called separate type metering valve.

  Specifically, the valve portion 41 is supported by the needle portion 42 so as to be capable of reciprocating in the axial direction in accordance with the pressure difference between the inside and outside of the pump chamber 18, and opens and closes the suction passage 18a. Further, the needle portion 42 is supported so as to be able to reciprocate in the axial direction of the needle portion 42 while restricting the range in which the valve portion 41 can reciprocate.

  Specifically, in the state where the needle portion 42 is pulled up most, the valve portion 41 can reciprocate according to the pressure difference between the fuel inside and outside the pump chamber 18 to open and close the suction passage 18a. On the other hand, in the state where the needle portion 42 is pushed down most, the valve portion 41 opens the suction passage 18a even when the fuel pressure in the pump chamber 18 is higher than the fuel pressure outside the pump chamber 18. ing.

  The urging spring 43 is provided at one end of the needle portion 42 opposite to the side from which the valve portion 41 protrudes, and urges the needle portion 42 and thus the metering valve 40 in the valve opening direction. The drive solenoid 44 is energized by the control device 60 to drive the needle portion 42 in the valve closing direction of the valve portion 41 by an electromagnetic force generated when a current flows. In addition, since the structure of the metering valve of such a separate structure is well known, further detailed explanation here is omitted.

  Hereinafter, the energization control of the drive solenoid 44 by the control device 60 will be described with reference to FIGS.

  FIG. 3 is a block diagram illustrating a configuration example of the control device 60 of the fuel supply system 1. The control device 60 is actually configured as a normal computer having a well-known CPU, for example, a memory such as a ROM or a RAM, an I / O, and a bus line (all not shown) for connecting them. However, here, conceptually, as shown in FIG. 3, it is assumed that the control device 60 includes an energization control unit 61 and a time measuring unit 62. The control device 60 is connected to the IG switch 51, the fuel pressure sensor 52, the crank angle sensor 53, etc., and acquires various information from them, and is connected to the high pressure fuel pump 3 to control the high pressure fuel pump 3. (Connected to the drive solenoid 44 and energization control of the drive solenoid 44 is performed).

  Among these, the energization control unit 61 performs energization control in either the energization mode in which the energization to the drive solenoid 44 is always energized or the emergency energization mode in which the energization mode to the drive solenoid 44 is not performed. .

  The timer 62 is composed of a known timer counter circuit and counts the continuous energization mode duration, which is the time during which the energization controller 61 continues to control the energization in the always energization control mode.

  FIG. 4 is a timing chart showing an example of energization control in the emergency energization mode. When energization control is performed in the emergency energization mode, the energization control unit 61 energizes the drive solenoid 44 based on the crank angle detected by the crank angle sensor 53.

  Specifically, when the plunger 11 descends toward its bottom dead center, the energization control unit 61 does not energize the drive solenoid 44. At this time, since the needle portion 42 is urged in the valve opening direction by the urging spring 43, the metering valve 40 is opened. In the open state of the metering valve 40, the low-pressure fuel is sucked into the pump chamber 18 as the plunger 11 is lowered (suction stroke).

  Specifically, as shown in FIG. 4A, the time when the plunger 11 reaches its bottom dead center from the time t12 when the discharge valve 20 closes when the fuel pressure in the pump chamber 18 falls below the predetermined pressure. The period up to t14 corresponds to the suction stroke.

  In this intake stroke, as shown in FIG. 4B, the energization control unit 61 turns off the energization to the drive solenoid 44. In this suction stroke, as shown in FIG. 4C, the force in the valve opening direction urged by the urging spring 43 to the metering valve 40 is metered by the fuel pressure difference inside and outside the pump chamber 18. At time t13 when the force in the valve closing direction applied to the valve 40 is exceeded, the metering valve 40 is opened.

  Even when the plunger 11 reaches its bottom dead center and rises toward the top dead center while the metering valve 40 is open, the energization controller 61 does not energize the drive solenoid 44. At this time, the fuel in the pump chamber 18 is returned via the metering valve 40 as the plunger 11 moves up (return stroke).

  Specifically, as shown in FIG. 4A, the return stroke is from time t14 when the plunger 11 reaches its bottom dead center to time t15 when the energization control unit 61 turns on the energization to the drive solenoid 44. It corresponds to. In this return stroke, as shown in FIG. 4B, the energization control unit 61 keeps the energization to the drive solenoid 44 off. Further, in this return stroke, as shown in FIG. 4C, the force in the valve opening direction urged by the urging spring 43 to the metering valve 40 is caused by the fuel pressure in the pump chamber 18. Since the force in the valve closing direction acting on the valve 40 is still higher, the metering valve 40 is in the valve open state.

  Then, as shown in FIG. 4B, the energization control unit 61 energizes the drive solenoid 44 at time t15 when the plunger 11 is rising toward its top dead center. When the drive solenoid 44 is energized, the needle portion 42 moves in the valve closing direction by electromagnetic force generated by the flow of current. When the needle portion 42 moves in the valve closing direction, the valve portion 41 moves in the axial direction due to the difference in fuel pressure inside and outside the pump chamber 18, so that the valve portion 41 also moves in the valve closing direction. As a result, the metering valve 40 is in a closed state.

  When the plunger 11 further rises toward its top dead center while the metering valve 40 is closed, the fuel pressure in the pump chamber 18 rises as the plunger 11 rises (pressurization stroke). Specifically, as shown in FIG. 4 (a), the discharge valve increases when the fuel pressure in the pump chamber 18 exceeds the predetermined pressure from time t15 when the energization controller 61 turns on the energization to the drive solenoid 44. The time until time t17 when the valve 20 opens corresponds to the pressurization stroke. In this pressurization stroke, as shown in FIG. 4B, the energization control unit 61 turns on energization to the drive solenoid 44 until time t16 when a predetermined time has elapsed from time t15. The predetermined time is a time when the force in the valve closing direction acting on the metering valve 40 by the fuel pressure in the pump chamber 18 exceeds the force in the valve opening direction acting on the metering valve 40 by the biasing spring 43. It is required through experiments and simulations. And after this time t16, the energization control unit 61 stops energization to the drive solenoid 44 (off). Even when the energization of the drive solenoid 44 is stopped, the valve closing state of the metering valve 40 is maintained as shown in FIG.

  Then, while the fuel pressure in the pump chamber 18 exceeds the predetermined pressure, the discharge valve 20 opens to supply high-pressure fuel to the delivery pipe 4 (supply stroke).

  Specifically, as shown in FIG. 4A, the period from time t17 when the fuel pressure in the pump chamber 18 exceeds the predetermined pressure to time t12 when the fuel pressure in the pump chamber 18 falls below the predetermined pressure corresponds to the supply stroke. To do.

  When energization control is performed in the emergency energization mode, the energization control unit 61 determines each stroke based on the crank angle detected by the crank angle sensor 53, and energizes the drive solenoid 44 according to each determined stroke. As a result, high pressure fuel is supplied to the delivery pipe 4. The amount of high-pressure fuel supplied is adjusted by controlling the energization timing (time t15) to the drive solenoid 44.

  By the way, if the metering valve 40 is opened at the time t11 when the plunger 11 reaches its top dead center, and the metering valve 40 is closed at the time t14 when the plunger 11 reaches its bottom dead center, the maximum value is obtained. It is known that a fuel supply amount is realized. However, particularly when the engine is started, it is difficult to accurately detect the position of the crankshaft by the crank angle sensor 53, and thus it is difficult to accurately detect the position of the plunger 11. Therefore, it is difficult to open the metering valve 40 at time t11 when the plunger 11 reaches its top dead center and to close the metering valve 40 at time t14 when the plunger 11 reaches its bottom dead center. .

  Therefore, in the present embodiment, the energization control unit 61 performs energization control in the always energized mode in which the energization to the drive solenoid 44 is always performed when the always energized mode execution start condition is satisfied. When energization control is performed in the constant energization mode, the needle portion 42 of the drive solenoid 44 is pulled up, and the valve portion 41 reciprocates according to the pressure difference between the inside and outside of the pump chamber 18. Specifically, when the fuel pressure in the pump chamber 18 is larger than the fuel pressure outside the pump chamber 18, the valve portion 41 moves upward and is in a closed state. On the other hand, when the fuel pressure in the pump chamber 18 is smaller than the fuel pressure outside the pump chamber 18, the valve portion 41 moves downward and opens.

  FIG. 5 is a timing chart showing an example of energization control in the constant energization mode. As shown in FIG. 5B, the drive solenoid 44 is always energized by the energization control unit 61.

  In this case, as shown in FIG. 5 (c), the metering valve 40 (specifically, the valve portion 41), for example, at time t21 when the plunger 11 reaches the top dead center and starts moving toward the bottom dead center. At t24, the fuel pressure in the pump chamber 18 becomes smaller than the fuel pressure outside the pump chamber 18, so that the valve is opened. On the other hand, as shown in FIG. 5 (c), the metering valve 40 has the fuel pressure in the pump chamber 18 at, for example, time t22 when the plunger 11 reaches the bottom dead center and starts moving toward the top dead center. Since it becomes larger than the fuel pressure outside the pump chamber 18, the valve is closed.

  Note that the time from the time t21 when the plunger 11 reaches the top dead center to the time t22 when the plunger 11 reaches the bottom dead center corresponds to the suction stroke. Further, the time from the time t22 when the plunger 11 reaches the bottom dead center to the time t23 when the fuel pressure in the pump chamber 18 exceeds the predetermined pressure and the discharge valve 20 opens corresponds to the pressurization stroke. Further, the period from time t23 to time t24 when the plunger 11 reaches the top dead center corresponds to the supply stroke.

  In this way, when energization control is performed in the constant energization mode, the metering valve 40 is opened when the plunger 11 reaches the top dead center, and the metering is performed when the plunger 11 reaches the bottom dead center. Since the valve 40 is closed, even if the crank angle cannot be accurately detected by the crank angle sensor 53, that is, even if the position of the crankshaft cannot be accurately detected, the maximum fuel supply amount is obtained. Can be realized.

  However, if the energization control time in the constant energization mode is long (for example, 1 second), the amount of heat generated by the drive solenoid 44 increases, so that the drive solenoid 44 itself melts down, and the metering valve 40 and eventually the fuel. It is also possible for the supply system 1 to fail.

  Therefore, in the present embodiment, the control device 60 counts the continuous energization mode duration, which is the time during which the energization control unit 61 continues to control energization in the always energization control mode, by the time counting unit 62, and When it is determined that the continuous energization mode duration time counted by the time measuring unit 62 has passed a predetermined determination time, the control unit 61 switches from the always energized mode to the emergency energization mode.

  In addition, the energization control unit 61 does not determine that the continuous energization mode duration time counted by the timing unit 62 has passed the predetermined determination time, but the difference between the actual fuel pressure detected by the fuel pressure sensor 52 and the target fuel pressure. Is determined to be smaller than the predetermined determination fuel pressure, the normal energization mode is switched to the emergency energization mode.

  Hereinafter, the energization mode switching process executed by the control device 60 will be described with reference to FIG. FIG. 6 is a flowchart illustrating an example of a processing procedure of the energization mode switching process. The energization mode switching process is started when the IG switch 51 is turned on.

  When the IG switch 51 is turned on and the energization mode switching process is started, the control device 60 first calculates the target fuel pressure and detects the actual fuel pressure as the process of step S10. Specifically, the control device 60 uses a preset value as the target fuel pressure of the high-pressure fuel stored in the delivery pipe 4 when the internal combustion engine is started, and after cranking, the control of the crank angle sensor 53 is performed. The rotational speed of the internal combustion engine is calculated from the detection result, and the target fuel pressure is set using this rotational speed. Specifically, when determining that the internal combustion engine is in the idling state, the control device 60 sets the target fuel pressure to, for example, “4 MPa”, and when determining that the internal combustion engine is in the low rotation speed state, the control device 60 sets the target fuel pressure to, for example, “6 to 12 MPa. If it is determined that the vehicle is in the middle / high rotational speed state, the target fuel pressure is set to, for example, “10 to 13 MPa”. Further, the actual fuel pressure is detected by a fuel pressure sensor 52 attached to the delivery pipe 4.

  When the setting of the target fuel pressure and the detection of the actual fuel pressure are finished, the control device 60 determines whether or not a predetermined constant energization mode execution start condition is satisfied as a determination process in subsequent step S20. In this embodiment, for example, “the target fuel pressure is greater than the actual fuel pressure when the IG switch 51 is turned on” is adopted as the constant energization mode execution start condition.

  When it is determined that the constant energization mode execution start condition is not satisfied (“No” in the determination process of step S20), the control device 60 (specifically, the energization control unit 61) performs the above-described process of step S70 as described above. Set to emergency energization mode. Therefore, the energization control unit 61 performs energization control to the drive solenoid 44 in the emergency energization mode.

  On the other hand, when it is determined in the determination process of the previous step S20 that the constant energization mode execution start condition is satisfied (“Yes” in the determination process of step S20), the energization control unit 61 performs the above-described process of step S30 as Set to always energized mode. Therefore, the normal control unit 61 constantly energizes the drive solenoid 44 in the always energized mode. In addition, the control device 60 (specifically, the timing unit 62) counts the continuous energization mode duration T as the processing of the subsequent step S40 in conjunction with the constant energization of the drive solenoid 44.

  Then, the energization control unit 61 determines whether or not the continuous energization mode duration T is longer than a predetermined determination time T1 (for example, “1 second”) as the determination process in the subsequent step S50. Here, when it is determined that the continuous energization mode duration time T is longer than the predetermined determination time T1 (“Yes” in the determination process of step S50), this means that there is a high possibility that the drive solenoid 44 is melted. . Therefore, in order to protect the drive solenoid 44, the energization control unit 61 proceeds to the subsequent step S70 and performs energization control of the drive solenoid 44 in the emergency energization mode. In the present embodiment, for example, “1 second” is adopted as the determination time T1, but the present invention is not limited to this. The time is not limited to “1 second” as long as it is shorter than the upper limit time during which the drive solenoid 44 is not melted due to continuous energization.

  On the other hand, in the determination process of step S50, when it is determined that the continuous energization mode duration T is shorter than the predetermined determination time T1 ("No" in the determination process of step S50), the drive solenoid 44 can be melted. Means low. Therefore, in order to realize the maximum supply amount of high-pressure fuel, the process proceeds to the previous step S30, and energization control of the drive solenoid 44 in the constant energization mode is continued.

  The energization control unit 61 then determines whether the difference obtained by subtracting the actual fuel pressure from the target fuel pressure set in the previous step S10 is smaller than a predetermined determination fuel pressure P1 (for example, “2 MPa”) as the determination process in step S60. Judge whether or not. Here, when it is determined that the difference is larger than the predetermined determination fuel pressure P1 ("No" in the determination process of step S60), it means that the actual fuel pressure deviates from the target fuel pressure. Therefore, in order to reduce the deviation of the actual fuel pressure from the target fuel pressure, the energization control unit 61 proceeds to the process of the previous step S30 and continues the energization control of the drive solenoid 44 in the always energized mode.

  On the other hand, if it is determined in the determination process of step S60 that the difference is smaller than the predetermined determination fuel pressure P1 ("Yes" in the determination process of step S60), it means that the actual fuel pressure is close to the target fuel pressure. In order to avoid that the actual fuel pressure exceeds the target fuel pressure (overshoot), the energization control unit 61 proceeds to the subsequent step S70 and performs energization control of the drive solenoid 44 in the emergency energization mode. In the present embodiment, for example, “2 MPa” is adopted as the determination fuel pressure P1, but the present invention is not limited to this. If it can be determined that the actual fuel pressure is approaching the target fuel pressure, the actual fuel pressure is not limited to “2 MPa”, and is arbitrary.

  Hereinafter, the operation of the present embodiment will be described with reference to FIG. FIG. 7A is a timing chart showing the change of the actual fuel pressure along with the change of the engine speed, and FIG. 7B is a timing chart showing the change of the ratio of the actual supply amount to the maximum supply amount of the high-pressure fuel. It is.

  For example, assume that the user turns on the IG switch 51 at time t1. At this time, as indicated by a solid line A, a broken line B, and a chain line C in FIG. 7A, the actual fuel pressure is approximately “0 MPa”, the rotational speed of the internal combustion engine is approximately “0 [rpm]”, and the target fuel pressure is “12 MPa”.

  At this time, since the constant energization mode execution start condition is satisfied (determination process in step S20), the control device 60 performs energization control of the drive solenoid 44 in the always energization mode. Thus, as shown in FIG. 7B, the maximum supply amount of high-pressure fuel (100 [%]) is realized, and the actual fuel pressure is directed toward the target fuel pressure as shown by a solid line A in FIG. Rise.

  As indicated by a broken line B in FIG. 7A, the rotational speed of the internal combustion engine rises slightly after time t1 when the IG switch 51 is turned on, and after this rise, about “300 [rpm]”. It becomes the cranking state of. When the cranking is finished, the rotational speed of the internal combustion engine stably changes at about “1000 [rpm]”.

  For example, at the time t3 when the determination time T1 has elapsed since the time t1, the continuous energization mode duration exceeds the determination time T1 (determination process in step S60), so the control device 60 is used for driving in the emergency energization mode. The energization control of the solenoid 44 is performed. Accordingly, as shown in FIG. 7B, the supply amount of the high-pressure fuel is approximately “15 to 20%” of the maximum supply amount (100%). As a result, as indicated by a solid line A in FIG. 7A, the actual fuel pressure almost stably overshoots the target fuel pressure and stably shifts with the target fuel pressure.

  In the above-described embodiment, the control device 60 is in either the energization mode in which the drive solenoid 44 is always energized or the emergency energization mode in which the drive solenoid 44 is not energized. An energization control unit 61 that controls energization, and a time counting unit 62 that counts the continuous energization mode duration T, which is the time during which the energization control unit 61 continues to perform energization control in the always energization control mode. The energization control unit 61 switches from the always energized mode to the emergency energized mode when it is determined that the constantly energized mode duration T measured by the timing unit 62 has passed the predetermined determination time Th. As a result, the energization of the drive solenoid 44 is continued until the continuous energization mode continuation time T has passed the determination time T1, so that the maximum fuel supply amount can be realized, while the determination time T1. After the time elapses, the drive solenoid is not always energized, and the drive solenoid is protected. As a result, the drive solenoid can be protected while achieving the maximum fuel supply amount.

  In the above embodiment, the energization control unit 61 is detected by the fuel pressure sensor 52 even if it is not determined that the continuous energization mode continuation time T measured by the time measuring unit 62 has passed the predetermined determination time T1. When it is determined that the difference between the actual fuel pressure and the target fuel pressure is smaller than the predetermined determination fuel pressure P1, the normal energization mode is switched to the emergency energization mode. Thus, since the emergency energization mode is switched to when the actual fuel pressure substantially matches the target fuel pressure, the energization is not always performed without waiting for the determination time T1 to elapse. Therefore, the occurrence of the actual fuel pressure exceeding the target fuel pressure (overshoot) can be reduced.

  In the above embodiment, the energization control unit 61 performs energization control in the always energized mode based on the determination that the always energized mode execution start condition is satisfied. Thus, the energization control is performed in the always energized mode only in a limited situation where it is determined that the predetermined always energized mode execution start condition is satisfied, so that the drive solenoid 44 can be further protected. Become.

  Note that the fuel supply system according to the present invention is not limited to the configuration exemplified in the above embodiment, and can be implemented with various modifications without departing from the spirit of the present invention. . In other words, for example, the following embodiment can be implemented by appropriately changing the above embodiment.

  In the above-described embodiment, for example, “the target fuel pressure is greater than the actual fuel pressure when the IG switch 51 is turned on” is used as the always-on mode execution start condition. It may be added that "there is no". That is, “the target fuel pressure is greater than the actual fuel pressure when the IG switch 51 is turned on” and “there is no pressure increase prohibition request” may be employed as the constant energization mode execution start condition. Incidentally, the pressure increase prohibition request is a signal indicating that a low pressure fuel pump 2 outputs an abnormality to the control device 60 when an abnormality occurs in the low pressure fuel pump 2, and a high pressure when an abnormality occurs in the high pressure fuel pump 3. At least one of a signal indicating that it is output from the fuel pump 3 to the control device 60 and a signal indicating that it is output from the fuel pressure sensor 52 to the control device 60 when an abnormality occurs in the fuel pressure sensor 52 It is possible to adopt one.

  In the above embodiment, the energization control unit 61 determines whether or not the above-described constant energization mode execution start condition is satisfied as the determination processing in step S20. However, the determination process in step S20 may be omitted. In detail, after the ignition switch 51 is turned on, the energization control may be performed in the always energized mode until the determination time T1 elapses.

  In the above embodiment, the energization control unit 61 determines the difference obtained by subtracting the actual fuel pressure from the target fuel pressure even if it is not determined that the continuous energization mode duration T timed by the time measuring unit 62 has passed the determination time T1. When it is determined that the fuel pressure is smaller than the fuel pressure P1, switching from the normal energization mode to the emergency energization mode (see the processes in steps S50 to S70) may omit the determination process in step S60.

  In the above embodiment, when energization control is performed in the emergency energization mode, the energization control unit 61 energizes the drive solenoid 44 based on the crank angle detected by the crank angle sensor 53. Not limited to. In addition, for example, a cam position sensor for a cam for a pump of an internal combustion engine (a cam for driving a high-pressure pump) and a position sensor for a cam for driving a valve are further provided, and the detection results of these various sensors in addition to the crank angle. The drive solenoid 44 may be energized based on the above.

1 is a block diagram showing an example of the overall configuration of an embodiment of a fuel supply system according to the present invention. It is a block diagram which shows the structural example about the metering valve of the fuel supply system of the said embodiment. It is a block diagram which shows the structural example about the control apparatus of the fuel supply system of the said embodiment. (A) is a timing chart showing the transition of the lift amount of the plunger 11 during energization control in the emergency energization mode. (B) is a timing chart showing the transition of the energization state to the drive solenoid 44. (C) is a timing chart showing the transition of the state of the metering valve 40. (A) is a timing chart showing the transition of the lift amount of the plunger 11 during energization control in the constant energization mode. (B) is a timing chart showing the transition of the energization state to the drive solenoid 44. (C) is a timing chart showing the transition of the state of the metering valve 40. It is a flowchart which shows an example of the process sequence about the electricity supply mode switching process performed by this Embodiment. (A) is a timing chart which shows transition of an actual fuel pressure with transition of the rotational speed of an internal combustion engine, when energization control is performed according to the present embodiment. (B) is a timing chart showing the transition of the ratio to the maximum supply amount of high-pressure fuel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel supply system, 2 ... Low pressure fuel pump, 3 ... High pressure fuel pump, 4 ... Delivery pipe, 5 ... Fuel injection valve, 11 ... Plunger, 16 ... Cam, 16a ... Cam shaft, 18 ... Pump chamber, 18a ... Suction Passage, 18b ... Supply passage, 20 ... Discharge valve, 30 ... Relief valve, 40 ... Metering valve, 41 ... Valve part, 42 ... Needle part, 43 ... Spring, 44 ... Solenoid for driving, 51 ... IG switch, 52 ... Fuel pressure sensor, 53... Crank angle sensor, 60... Control device, 61.

Claims (3)

By reciprocating the pump chamber having the suction passage and the supply passage based on the rotational movement of the crankshaft of the internal combustion engine, the fuel is sucked into the pump chamber from the suction passage, the pressurized fuel is sucked, and the pressure is increased. A plunger that supplies the fuel from the supply passage to the outside of the pump chamber, and a metering valve that opens and closes the suction passage according to the reciprocating motion of the plunger and adjusts the amount of fuel sucked into the pump chamber. A fuel supply system including a fuel pump and a control device that controls the fuel pump,
A delivery pipe connected to a supply passage of the fuel pump for storing the supplied fuel;
A fuel pressure sensor that detects an actual fuel pressure that is a pressure of fuel stored in the delivery pipe;
The metering valve is
A valve portion that opens and closes the suction passage by reciprocating according to the pressure difference between the fuel inside and outside the pump chamber;
A needle part configured separately from the valve part and restricting a range in which the valve part reciprocates; and
Biasing means for biasing the needle portion in the valve opening direction of the valve portion;
A drive solenoid that drives the needle portion in the valve closing direction of the valve portion;
The controller is
An energization control unit that controls energization in one of the energization mode of the always energization mode that always energizes the drive solenoid and the emergency energization mode that does not always energize the drive solenoid;
A timing unit that counts the continuous energization mode duration, which is the time during which the energization control unit continuously controls energization in the always energization control mode,
The energization control unit makes an emergency from the normal energization mode based on the determination that the continuous energization mode duration timed by the timekeeping unit has passed a determination time set to protect the drive solenoid. Even if it is not determined that the continuous energization mode duration time counted by the timing unit has passed the determination time, the difference between the actual fuel pressure detected by the fuel pressure sensor and the target fuel pressure is predetermined. A fuel supply system that switches from the always energized mode to the emergency energized mode based on being determined to be smaller than the determined fuel pressure . The fuel supply system according to claim 1, wherein
The energization control unit starts energization control in the constant energization mode on the condition that the target fuel pressure is larger than the actual fuel pressure at the time when the ignition switch is turned on, and at the time when the ignition switch is turned on. A fuel supply system, wherein energization control in the emergency energization mode is started when the condition is not satisfied . The fuel supply system according to claim 1 or 2,
A crank angle sensor for detecting rotation or crank angle of the crankshaft of the internal combustion engine;
The energization control unit energizes the drive solenoid based on a crank angle detected by the crank angle sensor when energization control is performed in an emergency energization mode.

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