JP2009144618A - Fuel feeding control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel feeding control device for an internal combustion engine capable of certainly suppressing leakage of a fuel from an injector during stopping of the engine. <P>SOLUTION: A relief valve 64 for relieving the fuel of a delivery pipe 63 is provided on the delivery pipe 63 for feeding the fuel to the injector 27. An electronic control device 100 switches the opened/closed state of the relief valve 64 between the valve-closed state in which the fuel in the delivery pipe 63 is not relieved and the valve-opened state in which the fuel in the delivery pipe 63 is relieved. The electronic control device 100 performs first relief processing for maintaining the relief valve 64 in the valve-opened state immediately after stopping of the internal combustion engine 1 and maintaining it in the valve-closed state after that; and second relief processing for maintaining the relief valve 64 in the valve-opened state again after the processing is completed and maintaining it in the valve-closed state after that. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel supply control device for an internal combustion engine that includes a fuel pipe that supplies fuel to an injector and a relief mechanism that relieves the fuel in the pipe.

As such a control device, a fuel pipe connected to a discharge port of a fuel pump and a fuel discharged from the fuel pump to each injector are generally known through this pipe.
By the way, in a vehicle equipped with the control device, after the internal combustion engine is stopped as the vehicle travels, the fuel leakage from the injector may occur due to the high pressure in the fuel pipe. Therefore, in order to suppress the occurrence of such fuel leakage, for example, Patent Document 1 proposes the following control device. That is, this control device is provided with a relief valve for relieving fuel in the fuel pipe, and opens the relief valve for a predetermined time immediately after the internal combustion engine is stopped, thereby reducing the internal pressure of the fuel pipe. I try to lower it.
JP 2002-317669 A

  By the way, unlike the case of traveling, the traveling wind is not supplied to the engine room that houses the internal combustion engine and the fuel pipe after the vehicle travels, so that the temperature in the engine room rises due to the residual heat of the internal combustion engine. For this reason, according to the control device of Patent Document 1, although the pressure in the fuel pipe can be once reduced immediately after the internal combustion engine is stopped, the pressure in the fuel pipe is again increased as the temperature in the engine room increases thereafter. This can lead to fuel leakage from the injector. After all, even if it is the control apparatus of the said patent document 1, as an apparatus which suppresses the fuel leak from an injector in an engine stop, the subject still remains in the reliability.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a fuel supply control device for an internal combustion engine that can accurately suppress fuel leakage from an injector while the engine is stopped.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1 includes a fuel pipe for supplying fuel to the injector and a relief mechanism for relieving the fuel in the pipe, and the operating state of the relief mechanism is a closed state in which the fuel in the fuel pipe is not relieved And an open state in which the fuel in the fuel pipe is relieved, the fuel supply control device for the internal combustion engine maintains the operating state of the relief mechanism in the open state immediately after the internal combustion engine is stopped, and thereafter Control means for performing a first relief process for maintaining the closed state and a second relief process for maintaining the relief mechanism in the open state again after the completion of the process and then maintaining the closed state in the closed state. This is the gist.

  According to the above-described invention, since the second relief process is performed, even if the pressure in the fuel pipe rises again after the first relief process is completed, the fuel leakage from the injector due to this is prevented. It becomes possible to suppress accurately. That is, it becomes possible to accurately suppress fuel leakage from the injector while the engine is stopped.

  According to a second aspect of the present invention, in the fuel supply control device for an internal combustion engine according to the first aspect, when the control means has a predetermined time after the first relief processing is completed. The gist is to execute the second relief process.

  According to a third aspect of the present invention, in the fuel supply control device for an internal combustion engine according to the second aspect, the control means changes the pressure in the fuel pipe after the first relief process is completed. The gist is to estimate the mode and to set the predetermined time based on the estimated change mode.

  According to the above invention, when the pressure in the fuel pipe is once reduced by the first relief process, and then the pressure rises to a level that causes fuel leakage from the injector based on the estimated pressure change mode. The second relief process can be executed. Therefore, the pressure in the fuel pipe can be efficiently reduced by the second relief process.

  According to a fourth aspect of the present invention, in the fuel supply control apparatus for an internal combustion engine according to the third aspect, the control means includes a pressure in the fuel pipe when the first relief processing is finished and the internal combustion engine. The gist of the present invention is to estimate the pressure change mode based on at least one of the environmental temperature and the cooling water temperature of the internal combustion engine.

  According to a fifth aspect of the present invention, in the fuel supply control device for an internal combustion engine according to the third or fourth aspect, the control means terminates the first relief process based on the estimated pressure change mode. The gist is to set the predetermined time as the time until the pressure reaches the determination pressure as the pressure in the fuel pipe increases later.

  According to the above invention, since the execution timing of the second relief process is set based on the comparison between the pressure in the fuel pipe and the determination pressure, fuel leakage from the injector can be more accurately suppressed. become.

  According to a sixth aspect of the present invention, in the fuel supply control device for an internal combustion engine according to the fifth aspect, the determination pressure is a pressure at which fuel leakage from the injector does not occur as the pressure in the fuel pipe increases. The gist is that the largest one is set.

  According to the above invention, since the second relief process is executed when the pressure in the fuel pipe rises to the maximum in a state where no fuel leaks from the injector, the pressure drop per relief process is performed. The amount becomes sufficiently large, and the pressure in the fuel pipe can be lowered with high efficiency.

  A seventh aspect of the present invention is the fuel supply control device for an internal combustion engine according to any one of the first to sixth aspects, wherein the injector is an in-cylinder injector, and the fuel pipe is connected to the injector with a high-pressure fuel. The main point is to supply

  In an internal combustion engine equipped with an in-cylinder injector, the pressure in the fuel pipe that supplies fuel to the injector becomes particularly high, so the frequency of fuel leakage from the injector when the engine is stopped increases. In this regard, according to the above invention, fuel leakage in the internal combustion engine is suppressed, so that the reliability of the direct injection internal combustion engine can be further improved.

An embodiment in which the present invention is applied to a fuel supply control device for an on-vehicle multi-cylinder internal combustion engine will be described below with reference to FIGS.
As shown in FIG. 1, a plurality of cylinders 11 (one of which is shown in FIG. 1) are formed in the cylinder block 10 of the internal combustion engine 1. A piston 12 that reciprocates within the cylinder 11 is provided. The piston 12 is connected to the crankshaft 14 via a connecting rod 13.

  A cylinder head 20 is assembled above the cylinder block 10. A combustion chamber 18 is defined by the cylinder block 10, the cylinder head 20, and the piston 12. An intake port 21 and an exhaust port 22 connected to the combustion chamber 18 are formed in the cylinder head 20. The intake port 21 is connected to the intake passage 23, while the exhaust port 22 is connected to the exhaust passage 24. An intake valve 30 and an exhaust valve 40 are provided for switching the communication state and the cutoff state between the ports 21 and 22 and the combustion chamber 18, respectively. In the intake stroke of the engine, when the intake valve 30 is opened, air is sucked into the combustion chamber 18 through the intake passage 23 and the intake port 21. Further, in the exhaust stroke of the engine, the exhaust valve 40 is opened, so that the burned gas in the combustion chamber 18 is discharged through the exhaust port 22 and the exhaust passage 24.

  The cylinder head 20 is provided with a plurality of in-cylinder injectors (hereinafter simply referred to as “injectors 27”) corresponding to the respective cylinders 11, and fuel supplied by the fuel supply device 60 is supplied from the injectors 27. It is injected directly into the combustion chamber 18.

  The cylinder block 10 is provided with a water temperature sensor 81 for detecting the cooling water temperature of the internal combustion engine 1, and a crank sensor 82 for detecting the rotation angle of the crankshaft 14 is provided in the vicinity of the crankshaft 14. It has been. Further, the intake passage 23 is provided with an intake air temperature sensor 83 for detecting the intake air temperature of the internal combustion engine. Detection signals of the water temperature sensor 81, the crank sensor 82, and the intake air temperature sensor 83 are taken into an electronic control unit 100 that includes a microcomputer 110 and performs overall control of the internal combustion engine 1.

  A microcomputer 110, which is the center of the electronic control device 100, has a central processing unit (CPU) 111 that performs numerical calculation, information processing, etc. according to control programs for various controls, these control programs, and various function maps required for the execution. A nonvolatile memory (ROM) 112 and a volatile memory (RAM) 113 for temporarily storing input data and calculation results.

  In addition, the electronic control device 100 is in a state in which the control operation can be executed by receiving power from the in-vehicle battery BT via the main relay MR maintained in the on state based on the on operation of the ignition switch IG. That is, when the ignition switch IG is turned on, the electronic control device 100 turns on the internal setting of the main relay MR and takes in the voltage VB of the in-vehicle battery BT. Based on this voltage VB, the microcomputer 110 and the internal combustion engine A voltage for driving each electric drive unit of the engine 1 is generated. When the ignition switch IG is turned off, the microcomputer 110 finishes predetermined post-processing, and then turns off the internal setting of the main relay MR to cut off the power supply from the in-vehicle battery BT to the electronic control unit 100.

  Furthermore, the electronic control device 100 is provided with a soak timer 120 for restarting the electronic control device 100 after a predetermined time has elapsed since power supply to the electronic control device 100 is stopped. In other words, the soak timer 120 stores the restart time Trs set by the microcomputer 110 in the storage unit 121, and the main relay after the restart time Trs has elapsed since the microcomputer 110 turned off the main relay MR. The electronic control device 100 can be activated by turning on the MR.

  On the other hand, the fuel supply device 60 includes a fuel tank 61 that stores fuel, a high-pressure pump 62 that is driven by the crankshaft 14, and a delivery pipe 63 that functions as fuel piping. The high pressure pump 62 has a suction port connected to the fuel tank 61 through the suction passage 71 and a discharge port connected to the delivery pipe 63 through the pressure feed passage 72 to pressurize the fuel in the fuel tank 61 and deliver the delivery pipe. Pump to 63. The delivery pipe 63 is connected to each injector 27 through the distribution passage 73, and supplies the high pressure fuel pumped by the high pressure pump 62 to the injector 27.

  The high-pressure pump 62 is provided with an electromagnetic valve 62a that can change the amount of fuel pumped by the high-pressure pump 62, and the delivery pipe 63 is provided with a fuel pressure sensor 84 for detecting the internal pressure. The electronic control unit 100 sets a target value for the internal pressure of the delivery pipe 63 (hereinafter referred to as “fuel pressure P”) based on the engine operating state, detects the fuel pressure P by the fuel pressure sensor 84, and this fuel pressure P The fuel pressure P is feedback-controlled so that the detected value coincides with the target value.

  The delivery pipe 63 is provided with a normally closed electromagnetic relief valve (hereinafter referred to as “relief valve 64”). The relief valve 64 is connected to the fuel tank 61 through the recovery passage 74, and the open / close valve state is controlled by the electronic control unit 100.

  That is, for example, when the fuel pressure P becomes higher than a predetermined limit pressure due to, for example, an abnormality of the electromagnetic valve 62a, the electronic control unit 100 energizes the relief valve 64 to open the relief valve 64. A part of the fuel in the delivery pipe 63 is relieved to the fuel tank 61 through the recovery passage 74. Thereby, it can suppress that the fuel pressure P rises excessively.

  Further, if the pressure of the delivery pipe 63 is maintained at a high pressure during normal operation after the internal combustion engine is stopped as the vehicle travels, fuel leakage from the injector 27 may occur. Therefore, immediately after the internal combustion engine 1 is stopped, in other words, immediately after the ignition switch IG is turned off, the relief valve 64 is opened for a predetermined time, thereby reducing the fuel pressure P and suppressing the occurrence of such fuel leakage. Can do.

  By the way, unlike when the vehicle is traveling, since the traveling wind is not supplied to the engine room that houses the internal combustion engine 1 and the fuel supply device 60, the temperature in the engine room rises due to the residual heat of the internal combustion engine 1. become. Therefore, although the fuel pressure P can be temporarily reduced immediately after the internal combustion engine 1 is stopped by opening the relief valve 64, the fuel pressure P increases again as the temperature in the engine room increases thereafter. There is a risk of fuel leakage from 27.

  Therefore, in the present embodiment, the second relief control is executed when a predetermined time elapses after the first relief control for opening the relief valve 64 for the first time in accordance with the turning-off operation of the ignition switch IG. As a result, fuel leakage from the injector 27 while the engine is stopped is more accurately suppressed.

  A detailed processing procedure of the first relief control will be described with reference to the flowchart of FIG. This relief control is started when the ignition switch IG is turned off.

  In this process, first, the relief valve 64 is energized to open the relief valve 64 (step S10). Then, it is determined whether or not the fuel pressure P of the delivery pipe 63 detected by the fuel pressure sensor 84 is equal to or lower than a predetermined low pressure PL (for example, “atmospheric pressure”) (step S20). Here, when it is determined that the detected fuel pressure P is higher than the predetermined low pressure PL (step S20: NO), the determination process of step S20 is executed until a predetermined standby time (for example, 1 second) elapses. Is held, and the determination process of step S20 is performed again when this waiting time has elapsed. And when it determines with the detected fuel pressure P being below the predetermined low pressure PL (step S20: YES), electricity supply to the relief valve 64 is interrupted | blocked and the relief valve 64 is closed (step S30). .

  In the next step S40, based on the fuel pressure P, the temperature of the engine room (environment temperature of the internal combustion engine 1), and the cooling water temperature when the processing of steps S10 to S30 (hereinafter referred to as “first relief processing”) is completed. Then, the change mode of the fuel pressure P after that point, specifically, the temporal transition mode of the fuel pressure P is estimated with reference to the calculation map. Here, the detected value of the intake air temperature sensor 83 is used as the temperature of the engine room. This calculation map is stored in advance in the ROM 112, and the fuel pressure P, the environmental temperature of the internal combustion engine 1 and the coolant temperature are given from the calculation map, and the change mode of the fuel pressure P after that point is read out. be able to.

  In the next step S50, the maximum value of the fuel pressure P when the internal combustion engine 1 is stopped (hereinafter referred to as “maximum pressure Pmax”) is calculated based on the estimated temporal transition of the fuel pressure P, and this maximum pressure is calculated. It is determined whether or not Pmax is higher than a preset determination pressure Pj (step S50). In the present embodiment, the determination pressure Pj is set to the highest pressure that does not cause fuel leakage from the injector 27 as the fuel pressure P increases.

  If it is determined that the estimated maximum pressure Pmax is higher than the determination pressure Pj (step S50: YES), a time Tj from that point in time until the fuel pressure P reaches the determination pressure Pj is set as a restart time Trs. The main relay MR is turned off by being stored in the storage unit 121 of the soak timer 120 (step S60), and this series of processes is temporarily terminated. On the other hand, when it is determined that the estimated maximum pressure Pmax is equal to or less than the determination pressure Pj (step S50: NO), the restart time Trs stored in the storage unit 121 of the soak timer 120 is cleared and the main relay MR is turned on. The turning-off operation is performed (step S70), and this series of processing is once ended.

  That is, when it is determined in step S50 that the estimated maximum pressure Pmax is higher than the determination pressure Pj (step S50: YES), when the restart time Trs has elapsed after the first relief control is completed. The electronic control device 100 is activated again by the soak timer 120, and the second relief control described below is executed. On the other hand, when it is determined that the maximum pressure Pmax is equal to or lower than the determination pressure Pj (step S50: NO), the possibility of fuel leakage from the injector 27 during the stop of the internal combustion engine 1 is extremely low. Until the next start of 1 is performed, the electronic control unit 100 is not started, and the second relief control is not executed.

  The detailed processing procedure of the second relief control will be described below with reference to the flowchart of FIG. This relief control is started when the restart time Trs has elapsed since the completion of the first relief control, that is, when the electronic control device 100 is restarted by the soak timer 120.

  In this process, first, the relief valve 64 is energized to open the relief valve 64 (step S110). Then, it is determined whether or not the fuel pressure P of the delivery pipe 63 detected by the fuel pressure sensor 84 is equal to or lower than the predetermined low pressure PL (step S120).

  Here, when it is determined that the detected fuel pressure P is higher than the predetermined low pressure PL (step S120: NO), execution of the determination process of step S120 is suspended until the predetermined standby time has elapsed, When this standby time has elapsed, the determination process of step S120 is performed again. And when it determines with the detected fuel pressure P being below the predetermined low pressure PL (step S120: YES), electricity supply to the relief valve 64 is interrupted | blocked and the relief valve 64 is closed (step S130). .

  Then, after the processing of steps S110 to S130 (hereinafter referred to as “second relief processing”) is completed, the restart time Trs stored in the storage unit 121 of the soak timer 120 is cleared and the main relay MR is turned off. (Step S140), and this series of processes is temporarily terminated.

  Next, an example of the relief control will be described with reference to FIG. Note that FIG. 4 shows temporal changes in the fuel pressure P, the opening / closing state of the relief valve 64, the on / off state of the ignition switch IG, and the intake air temperature after the ignition switch IG is turned off in accordance with the relief control. It is a timing chart which shows.

  The first relief control is executed when the ignition switch IG is turned off (time t0). That is, the relief valve 64 is energized and opened at time t0 (step S10), and a part of the fuel in the delivery pipe 63 is relieved, so that the fuel pressure P decreases. When it is determined at time t1 that the fuel pressure P has decreased to atmospheric pressure (step S20: YES), the energization of the relief valve 64 is cut off and the relief valve 64 is closed (step S30).

  Then, based on the fuel pressure P at time t1, the environmental temperature of the internal combustion engine 1, and the coolant temperature, the temporal transition mode of the fuel pressure P after time t1 is estimated with reference to the calculation map (step S40). Here, the broken line in FIG. 4 shows the temporal transition of the estimated fuel pressure P. As indicated by the broken line in FIG. 4, the fuel pressure P once increases as the environmental temperature increases from time t1.

  At this time, since the maximum pressure Pmax1 when the internal combustion engine 1 is stopped calculated based on the temporal transition mode of the fuel pressure P is higher than the preset determination pressure Pj1 (step S50: YES), from time t1. After the time Tj1 until the fuel pressure P reaches the determination pressure Pj1 (time t2) is stored as the restart time Trs in the storage unit 121 of the soak timer 120, the main relay MR is turned off, and the first relief control ends. (Step S60).

  Then, when the restart time Trs elapses after the first relief control ends (time t2), the second relief control is executed. That is, the relief valve 64 is energized and opened at time t2 (step S110), and a part of the fuel in the delivery pipe 63 is relieved, so that the fuel pressure P decreases. If it is determined at time t3 that the fuel pressure P has decreased to atmospheric pressure (step S120: YES), the energization of the relief valve 64 is cut off and the relief valve 64 is closed (step S30). Then, the main relay MR is turned off, and the second relief control is ended (step S140).

  Here, as indicated by the one-dot chain line in FIG. 4, after the second relief control is finished (time t3), the fuel pressure P may rise again as the environmental temperature rises. However, the delivery is performed by the second relief control. Since a part of the fuel in the pipe 63 has been relieved, the maximum value Pmax2 of the fuel pressure P after the end of the second relief control becomes a value smaller than the maximum pressure Pmax1.

According to the embodiment described above, the following effects can be obtained.
(1) The second relief control is executed when the restart time Trs has elapsed since the end of the first relief control. For this reason, even if the internal pressure of the delivery pipe 63, that is, the fuel pressure P rises again after the end of the first relief control, the fuel leakage from the injector 27 due to this can be suppressed accurately. That is, fuel leakage from the injector 27 while the engine is stopped can be accurately suppressed.

  (2) Estimate the temporal transition of the fuel pressure P after the end of the first relief process, and set the restart time Trs to the time Tj until the fuel pressure P reaches the judgment pressure Pj from this time point. I did it. As a result, after the fuel pressure P is once reduced by the first relief process, the second pressure is reached when the fuel pressure P rises to the extent of causing fuel leakage from the injector 27 based on the estimated change of the fuel pressure P. The relief process can be executed. Therefore, the fuel pressure P can be efficiently reduced by the second relief process. Since the execution timing of the second relief process is set based on the comparison between the fuel pressure P and the determination pressure Pj, the fuel leakage from the injector 27 can be more accurately suppressed.

  (3) The determination pressure Pj is set to the highest pressure among the pressures at which fuel leakage from the injector 27 does not occur as the fuel pressure P increases. As a result, the second relief process is executed when the fuel pressure P rises to the maximum in a state in which no fuel leaks from the injector 27, and therefore the amount of pressure decrease per relief process is sufficiently large. Thus, the fuel pressure P can be reduced with high efficiency.

  (4) In addition, power supply to the electronic control device 100 can be temporarily stopped between the end of the first relief control and the start of the second relief control. Therefore, for example, compared with the case where the relief valve 64 is controlled while monitoring the fuel pressure P through the fuel pressure sensor 84 after the first relief process is completed, it is possible to save power.

  (5) Since the change mode of the fuel pressure P is estimated based on the fuel pressure P at the time when the first relief process is completed, the environmental temperature of the internal combustion engine 1 and the cooling water temperature, the change mode can be estimated accurately. become.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
In the above embodiment, the relief valve 64 is closed on the condition that the fuel pressure P is equal to or lower than the predetermined low pressure PL in step S20 of the first relief control and step S120 of the second relief control. For example, the relief valve 64 may be closed on the condition that a preset valve opening time has elapsed since the relief valve 64 was opened. Further, in order to prevent the deterioration of engine startability due to excessive decrease in fuel pressure P at the next engine start, the second is within a range where fuel leakage from the injector 27 can be ignored. It is desirable to set the valve opening time of the relief valve 64 in the relief process to be shorter than the valve opening time of the relief valve 64 in the first relief process.

  In the above embodiment, after the second relief process is completed, the restart time Trs stored in the storage unit 121 of the soak timer 120 is cleared and the main relay MR is turned off. In order to suppress the fuel leakage more accurately, the change mode of the fuel pressure P after the end of the second relief process is estimated again, and the relief process (steps S40 to S40) is performed based on the estimated change mode of the fuel pressure P. A configuration in which step S70) is repeatedly executed can be employed.

  In the above embodiment, the determination pressure Pj is set to the highest pressure among the pressures at which fuel leakage from the injector 27 with the increase in the fuel pressure P does not occur. Not limited to this, the determination pressure Pj may be set to a pressure smaller than the largest pressure that does not cause fuel leakage. In addition, when the amount of fuel leakage is negligible between the time when the internal combustion engine 1 is stopped and the time when the fuel pressure P becomes the determination pressure Pj, the determination pressure Pj is greater than the highest pressure that does not cause fuel leakage. May be set to a large pressure.

  In the above embodiment, the second relief control is prohibited when it is determined in step S50 of the first relief control that the maximum pressure Pmax is equal to or less than the determination pressure Pj. On the other hand, the determination in step S50 may be omitted, and the second relief control may be executed regardless of the estimated maximum pressure Pmax value. Specifically, for example, the time until the fuel pressure P reaches the maximum pressure Pmax in step S40 is estimated, and the time is stored in the storage unit 121 of the soak timer 120 as the restart time Trs to turn off the main relay MR. Can be adopted.

  In the above-described embodiment, the change mode of the fuel pressure P after the first relief process is estimated, and the restart time Trs is set based on the estimated change mode. However, the present invention is not limited to this, and a configuration in which the second relief process is executed when a preset time (for example, 20 minutes) has elapsed since the completion of the first relief process may be employed. In addition, after the first relief process is completed, the relief process may be executed a plurality of times at a preset time interval.

  In the above embodiment, the change mode of the fuel pressure P is estimated based on the fuel pressure P at the time when the first relief process is completed, the environmental temperature of the internal combustion engine 1 and the cooling water temperature. Among these parameters, The change mode of the fuel pressure P may be estimated based on any one or two. In addition to the fuel pressure P, the environmental temperature of the internal combustion engine 1 and the cooling water temperature, a configuration including the atmospheric temperature can be adopted as a parameter for estimating the fuel pressure P.

  In the above embodiment, power supply to the electronic control device 100 can be temporarily stopped between the end of the first relief process and the start of the second relief process. On the other hand, it is also possible to employ a configuration in which the power supply to the electronic control device 100 is maintained after the first relief process is completed, and the relief valve 64 is controlled while the fuel pressure P is monitored by the fuel pressure sensor 84. When such a configuration is adopted, it is possible to omit the estimation of the change mode of the fuel pressure P accompanying the end of the first relief process.

  In the above embodiment, the case where the present invention is applied to the fuel supply control device of the internal combustion engine that relieves the fuel in the delivery pipe 63 through the electromagnetic relief valve 64 is illustrated, but the present invention is not limited to this, for example, a hydraulic relief valve The present invention can be basically applied to a fuel supply control device for an internal combustion engine that relieves the fuel in the delivery pipe 63 through another type of relief mechanism.

  In the above embodiment, the case where the present invention is applied to the fuel supply control device for an internal combustion engine that supplies high-pressure fuel to the in-cylinder injector 27 is illustrated, but the present invention is not limited thereto, and the internal combustion engine that supplies fuel to the port injector The present invention can also be applied to the engine fuel supply control device basically in the same manner. As the internal combustion engine, a gasoline engine, a diesel engine, an alcohol fuel engine, or the like can be appropriately employed.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows the outline | summary about one Embodiment of the fuel supply control apparatus of the internal combustion engine concerning this invention. The flowchart which shows the process sequence about the 1st relief control by the control apparatus of the embodiment. The flowchart which shows the process sequence about the 2nd relief control by the control apparatus of the embodiment. The timing chart which shows the temporal transition aspect of the fuel pressure after the ignition switch IG is turned off, the open / close state of the relief valve, the on / off state of the ignition switch, and the intake air temperature in accordance with the first and second relief control.

Explanation of symbols

  BT ... vehicle-mounted battery, IG ... ignition switch, MR ... main relay, 1 ... internal combustion engine, 10 ... cylinder block, 11 ... cylinder, 12 ... piston, 13 ... connecting rod, 14 ... crankshaft, 18 ... combustion chamber, 20 ... Cylinder head, 21 ... intake port, 22 ... exhaust port, 23 ... intake passage, 24 ... exhaust passage, 27 ... in-cylinder injector, 30 ... intake valve, 40 ... exhaust valve, 60 ... fuel supply device, 61 ... fuel tank 62 ... High pressure pump, 62a ... Solenoid valve, 63 ... Delivery pipe, 64 ... Relief valve, 71 ... Suction passage, 72 ... Pumping passage, 73 ... Distribution passage, 74 ... Recovery passage, 81 ... Water temperature sensor, 82 ... Crank sensor , 83 ... Intake air temperature sensor, 84 ... Fuel pressure sensor, 100 ... Electronic control device, 110 ... Microcomputer, 11 ... central processor, 112 ... non-volatile memory (ROM), 113 ... volatile memory (RAM), 120 ... soak timer, 121 ... storage unit.

Claims (7)

A fuel pipe for supplying fuel to the injector and a relief mechanism for relieving the fuel in the pipe are provided. The operating state of the relief mechanism is a closed state in which the fuel in the fuel pipe is not relieved, and the fuel in the fuel pipe is relieved. In the fuel supply control device for an internal combustion engine that switches between the open state and the open state,
Immediately after the internal combustion engine is stopped, the relief mechanism maintains the operating state in the open state, and then maintains the closed state in the closed state. After the completion of the processing, the relief mechanism is returned to the open state. A fuel supply control device for an internal combustion engine, comprising: a control unit that performs a second relief process for maintaining and then maintaining the closed state. The fuel supply control device for an internal combustion engine according to claim 1,
The fuel supply control device for an internal combustion engine, wherein the control means executes the second relief process when an elapsed time after the completion of the first relief process reaches a predetermined time. The fuel supply control device for an internal combustion engine according to claim 2,
The control means estimates a change mode of the pressure in the fuel pipe after the first relief process is completed, and sets the predetermined time based on the estimated change mode. A fuel supply control device for an internal combustion engine. The fuel supply control device for an internal combustion engine according to claim 3,
The control means changes the pressure based on at least one of the pressure in the fuel pipe, the environmental temperature of the internal combustion engine, and the cooling water temperature of the internal combustion engine when the first relief process is finished. A fuel supply control device for an internal combustion engine, characterized in that: The fuel supply control device for an internal combustion engine according to claim 3 or 4,
Based on the estimated pressure change mode, the control means determines the time until the pressure reaches the determination pressure as the pressure in the fuel pipe rises after the first relief process is completed. A fuel supply control device for an internal combustion engine, characterized by being set as a predetermined time. The fuel supply control apparatus for an internal combustion engine according to claim 5,
The fuel supply control device for an internal combustion engine, wherein the determination pressure is set to the highest pressure that does not cause fuel leakage from the injector as the pressure in the fuel pipe increases. The fuel supply control device for an internal combustion engine according to any one of claims 1 to 6,
The fuel supply control device for an on-vehicle internal combustion engine, wherein the injector is an in-cylinder injector, and the fuel pipe supplies high-pressure fuel to the injector.

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