JP2012237224A - Device and method for control of accumulator fuel injection device as well as accumulator fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and method for control of an accumulator fuel injection device, as well as the accumulator fuel injection device, capable of minimally suppressing the power consumption of a battery required for actuation of a pressure control valve at idling-stop control.SOLUTION: The control device is for controlling the accumulator fuel injection device including a common rail, a pressure control valve having a normally open type structure and a fuel injection valve connected to the common rail to inject fuel into cylinders of the internal combustion engine, and includes: an idling-stop control means for performing automatic stop and restart of the internal combustion engine; and a pressure control valve energization current value learning means for learning an energization current value of the pressure control valve during the automatic stop based on a pressure drop value in the common rail during the automatic stop.

Description

  The present invention relates to a control device and control method for an accumulator fuel injection device, and an accumulator fuel injection device. In particular, the present invention relates to a control device and a control method for controlling an accumulator fuel injection device that includes a pressure control valve having a normally open structure and that can execute idling stop control of an internal combustion engine, and an accumulator fuel injection device.

  2. Description of the Related Art Conventionally, as a device for injecting fuel into a cylinder of an internal combustion engine such as a diesel engine, an accumulator fuel injection device having a common rail for accumulating fuel pressurized by a high pressure pump has been used. A plurality of fuel injection valves are connected to the common rail, and energization control of each fuel injection valve is performed in a state where high-pressure fuel is supplied to each fuel injection valve, so that the internal combustion engine has various injection patterns. Fuel is injected into the cylinder.

  In such an accumulator fuel injection device, the pressure in the common rail (hereinafter referred to as “rail pressure”) greatly affects the fuel injection characteristics. As a method for controlling the rail pressure, the opening of the pressure control valve connected to the common rail is adjusted according to the target value of the rail pressure (hereinafter referred to as “target rail pressure”), and the rail pressure is discharged to the low pressure side. There is a method of controlling rail pressure by adjusting the flow rate of fuel.

  As this pressure control valve, a valve member that opens and closes the fuel flow path is biased in the valve opening direction by the biasing force of the spring, and has a normally open type structure in which the fuel flow path is opened in a non-energized state There is. Generally, the rail pressure is reduced when the internal combustion engine is stopped, but if a pressure control valve having a normally open type structure is used, the rail pressure can be reduced without performing energization control when the internal combustion engine is stopped. it can.

  By the way, in recent years, in the control of an internal combustion engine equipped with a pressure accumulating fuel injection device, the internal combustion engine has been temporarily stopped during the suspension of a vehicle on which the internal combustion engine is mounted for the purpose of improving fuel consumption and reducing the amount of exhaust gas and noise. The idling stop control that automatically stops is starting to be put into practical use. In the idling stop control, the internal combustion engine is automatically stopped when a predetermined idling stop condition is satisfied, and the internal combustion engine is restarted when a predetermined restart condition is satisfied.

  In a vehicle capable of performing idling stop control of the internal combustion engine, restartability from the automatic stop state is an element that has an important influence on the merchantability, and fuel injection is possible during the temporary stop of the internal combustion engine. There has been proposed a control device that can maintain the state and improve the restartability of the internal combustion engine during the idling stop control. Specifically, an engine automatic stop / restart device for automatically stopping and restarting the engine is provided, and the engine is stopped without operating the engine automatic stop / restart device. Sometimes the rail pressure is reduced, and when the engine is stopped by operating the engine automatic stop / restart device, the rail pressure when the engine is stopped without operating the engine automatic stop / restart device is reduced. A control device is disclosed that reduces the amount of decrease in rail pressure less than the amount of decrease (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2003-41978

  The control device described in Patent Document 1 includes a normally closed type pressure reducing valve (pressure control valve) connected to a common rail. When the ignition switch is turned off and the internal combustion engine is stopped, the pressure control valve is turned off. While driving and lowering the rail pressure, the pressure reducing valve is closed without driving the pressure control valve when the internal combustion engine is stopped by the idling stop control.

  On the other hand, when a normally open pressure control valve is used, in order to close the pressure control valve when the internal combustion engine is automatically stopped by idling stop control, the pressure control valve is energized, and the valve member An electromagnetic force for urging the valve member in the valve closing direction must be generated against the sum of the urging force of the spring that urges the valve member in the valve opening direction and the rail pressure.

  Here, the mass-produced pressure control valve has some variation in the electromagnetic force generated with respect to the energization current value. Therefore, the energizing current value of the pressure control valve at the time of idling stop control can be closed even when a pressure control valve (hereinafter referred to as a lower limit product) that generates the smallest electromagnetic force is used. It has become a value. However, on the other hand, when a pressure control valve other than the lower limit product is used, a current more than necessary is caused to flow during idling stop control, resulting in wasted power consumption of the battery.

  Accordingly, the inventors of the present invention have made diligent efforts to measure the amount of rail pressure decrease during the automatic stop of the internal combustion engine by idling stop control, and adjust the energization current value of the pressure control valve according to the measured value. The inventors have found that such a problem can be solved by learning the optimum value of the current, and have completed the present invention. That is, the present invention provides a pressure accumulation type fuel injection device control device and control method, and a pressure accumulation type fuel injection device capable of minimizing the power consumption of the battery for the operation of the pressure control valve during idling stop control. To do.

  According to the present invention, a common rail that accumulates fuel pumped by a high-pressure pump, and a valve that adjusts the pressure in the common rail and has a normally open structure that opens a fuel passage in a non-energized state. A control device for controlling an accumulator fuel injection device comprising a valve and a fuel injection valve connected to a common rail and injecting fuel into a cylinder of the internal combustion engine, the automatic stop and restart of the internal combustion engine Idling stop control means for performing, and pressure control valve energization current value learning means for learning the energization current value of the pressure control valve during the automatic stop based on the pressure drop amount in the common rail during the automatic stop. A control device for a pressure-accumulating fuel injection device is provided.

  In configuring the control device for the accumulator fuel injection device of the present invention, the pressure control valve energization current value learning means reduces the energization current value when the pressure drop amount is less than a predetermined value, while the pressure drop amount is It is preferable to learn the energization current value of the pressure control valve by increasing the energization current value when the value is equal to or greater than the predetermined value.

  Further, when configuring the control device for the accumulator fuel injection device of the present invention, the pressure control valve energization current value learning means, when increasing the energization current value, the increased energization current value is equal to or greater than a predetermined limit value. At this time, it is preferable that the energization current value is decreased stepwise, and the previous energization current value is used as a learning value when the pressure decrease after the decrease exceeds the previous pressure decrease amount.

  Another aspect of the present invention is a pressure accumulation type fuel injection device including any one of the control devices described above.

  Another aspect of the present invention is a common rail for accumulating fuel pumped by a high pressure pump, and a valve for adjusting the pressure in the common rail, and a normally open structure that opens the fuel passage in a non-energized state. A control method for controlling an accumulator fuel injection device comprising: a pressure control valve having a pressure control valve; and a fuel injection valve that is connected to a common rail and injects fuel into a cylinder of the internal combustion engine. Control of the accumulator fuel injection device, which learns the energization current value of the pressure control valve during the automatic stop based on the pressure drop amount in the common rail during the automatic stop during the idling stop control that performs the restart Is the method.

  According to the control device and the control method of the pressure accumulation type fuel injection device and the pressure accumulation type fuel injection device of the present invention, the pressure during the automatic stop is based on the pressure drop amount in the common rail during the automatic stop of the internal combustion engine by the idling stop control. By learning the energization current value of the control valve, it is possible to minimize the power consumption of the battery for the operation of the pressure control valve during the idling stop control.

  Further, according to the control device for an accumulator fuel injection device of the present invention, the energization current value is decreased when the pressure drop amount is less than a predetermined value, while the energization current value is reduced when the pressure drop amount is not less than the predetermined value. By learning the energizing current value of the pressure control valve by increasing the pressure control valve energizing current in both cases where the electromagnetic force for closing the pressure control valve is greater than necessary or insufficient. Can be learned.

  Further, according to the control device for an accumulator fuel injection device of the present invention, when the energized current value is increased, the energized current value is decreased stepwise when the increased energized current value exceeds a predetermined limit value. When the pressure drop amount after the decrease exceeds the previous pressure drop amount, the previous energization current value is used as a learning value, so that the pressure drop over a predetermined value is due to factors other than the pressure control valve. In addition, the optimum value of the pressure control valve energization current can be learned.

1 is an overall view showing a configuration example of a pressure accumulation fuel injection device in an embodiment of the present invention. It is a block diagram for demonstrating the control apparatus of the pressure accumulation type fuel injection apparatus in embodiment of this invention. It is a flowchart which shows an example of the procedure of pressure control valve electric current value learning. It is a flowchart which shows an example of the procedure of electric current reduction search mode. It is a flowchart which shows an example of the procedure of electric current increase search mode. It is a flowchart which shows an example of the procedure of compromise current search mode.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments relating to an accumulator fuel injection device control device and control method and an accumulator fuel injection device according to the present invention will be specifically described below with reference to the drawings as appropriate. However, this embodiment shows one aspect of the present invention and does not limit the present invention, and can be arbitrarily changed within the scope of the present invention. In addition, what attached | subjected the same code | symbol in each figure has shown the same member, and description is abbreviate | omitted suitably.

1. Accumulated Fuel Injection Device FIG. 1 shows an overall configuration of an accumulator fuel injection device 10 according to an embodiment of the present invention. This accumulator fuel injection device 10 is a device for injecting fuel into a cylinder of an internal combustion engine (not shown) mounted on a vehicle, and includes a fuel tank 1, a low pressure pump 11, a high pressure pump 13, and a flow rate control. A valve 19, a common rail 15, a pressure control valve 23, a fuel injection valve 17, a control device 50 (ECU), and the like are provided as main elements.

  The low pressure pump 11 and the pressurization chamber 13a of the high pressure pump 13 are connected by a low pressure fuel passage 31. The pressurization chamber 13a and the common rail 15 of the high pressure pump 13 and the common rail 15 and the fuel injection valve 17 are respectively connected to the high pressure fuel passages 33 and 35. Connected with. In addition, return passages 37, 38, 39 for returning surplus fuel not injected from the fuel injection valve 17 to the fuel tank 1 are connected to the high-pressure pump 13, the common rail 15, and the fuel injection valve 17.

  A flow rate control valve 19 for adjusting the flow rate of the fuel sent to the pressurizing chamber 13 a is provided in the middle of the low pressure fuel passage 31 in the high pressure pump 13. As the flow control valve 19, for example, an electromagnetic proportional flow control valve in which the stroke amount of the valve member is variable depending on the supply current value and the area of the fuel passage is adjustable is used. The flow control valve 19 of the present embodiment is configured as a normally open flow control valve in which a fuel flow path is fully opened in a non-energized state. However, it may be a normally closed flow control valve in which the fuel flow path is fully closed in a non-energized state.

  A pressure adjusting valve 21 arranged in parallel with the flow control valve 19 is provided in a fuel passage branched from the low pressure fuel passage 31 upstream of the flow control valve 19 in the high pressure pump 13. The pressure regulating valve 21 is connected to a return passage 37 that communicates with the fuel tank 1, and the difference between the front and rear pressures, that is, the difference between the pressure in the low-pressure fuel passage 31 and the pressure in the return passage 37 exceeds a predetermined value. An overflow valve that is opened when the valve is opened is used. In a state where the fuel is being pumped by the low pressure pump 11, the pressure in the low pressure fuel passage 31 is adjusted so as to be larger than the pressure in the return passage 37 by a predetermined differential pressure.

  The low pressure pump 11 sucks up and pumps the fuel in the fuel tank 1, and supplies the fuel to the pressurizing chamber 13 a of the high pressure pump 13 through the low pressure fuel passage 31. The low-pressure pump 11 is an in-tank electric pump provided in the fuel tank 1 and is driven by a current supplied from a battery. However, the low pressure pump 11 may be provided outside the fuel tank 1 or may be a gear pump that is driven by power of an internal combustion engine (not shown).

  The high pressure pump 13 pressurizes fuel introduced into the pressurizing chamber 13 a via the fuel intake valve 27 by the low pressure pump 11 by the plunger 29, and supplies high-pressure fuel to the common rail via the fuel discharge valve 28 and the high pressure fuel passage 33. 15 is pumped. The fuel discharge valve 28 has a check valve structure in which the sealing performance is enhanced as the rail pressure located on the discharge side is higher.

  A cam 14 for driving the high-pressure pump 13 is fixed to a camshaft connected to a driveshaft of an internal combustion engine (not shown) via a gear. The high-pressure pump 13 shown in FIG. 1 includes two plungers 29. The two plungers 29 are pushed up by the cam 14, and the fuel is pressurized in the two pressurizing chambers 13a. The fuel is pumped. Although the high-pressure pump 13 of this embodiment is comprised including the two plungers 29 and the pressurization chamber 13a, the number of plungers is not limited to this.

  The high pressure pump 13 shown in FIG. 1 is provided with a fuel temperature sensor 24. The sensor signal St of the fuel temperature sensor 24 is sent to the control device 50, and the fuel temperature Tf flowing through the low pressure fuel passage 31 is detected based on the sensor signal St. However, the fuel temperature sensor may be provided at any location in the fuel passage in the accumulator fuel injection device 10.

  The common rail 15 accumulates high-pressure fuel pressurized by the high-pressure pump 13 and supplies the fuel to the fuel injection valve 17 connected via the high-pressure fuel passage 35. A rail pressure sensor 25 and a pressure control valve 23 are attached to the common rail 15. The sensor signal Sp of the rail pressure sensor 25 is sent to the control device 50, and the rail pressure Pr is detected based on the sensor signal Sp.

  The pressure control valve 23 is used to adjust the flow rate of the high-pressure fuel that is returned from the common rail 15 to the fuel tank 1. The pressure control valve 23 is an electromagnetic proportional control valve in which the stroke amount of the valve member for opening and closing the fuel passage is variable depending on the supply current value, and the area of the fuel passage is adjustable. The pressure control valve 23 of the present embodiment is configured as a normally open pressure control valve in which the fuel flow path is fully opened in a non-energized state. A normally open type pressure control valve opens when the sum of the biasing force of the spring that biases the valve member in the valve opening direction and the rail pressure exceeds the force that biases the valve member in the valve closing direction. .

  The fuel injection valve 17 includes a nozzle body provided with injection holes and a nozzle needle that opens and closes the injection holes by advancing and retreating. The fuel injection valve 17 closes the injection hole by applying a back pressure to the rear end side of the nozzle needle, while opening the injection hole by releasing the applied back pressure. When the rail pressure is equal to or higher than the injectable pressure, normal fuel injection by the fuel injection valve 17 is possible. As the fuel injection valve 17, an electrostrictive piezo injector provided with a piezo element as back pressure control means or an electromagnetic control type magnet injector provided with an electromagnetic solenoid as back pressure control means is used.

  It should be noted that the fuel injection valve 17 provided in the accumulator fuel injection device 10 of the present embodiment does not cause a leak (static leak) that leaks from a minute gap other than a dynamic leak, or an extremely small amount of leak. It has a structure that only occurs.

  The flow rate control valve 19 and the pressure control valve 23 are energized and controlled by the control device 50. The fuel passage area changes proportionally according to the energization amount (operation amount), and the flow rate of the fuel passing therethrough. Is to be adjusted. In this accumulator type fuel injection device 10, the actual rail pressure Pr detected by the pressure sensor 25 is equal to the target rail pressure Ptgt using the flow control valve 19 or the pressure control valve 23, or using both control valves in combination. Control is performed so that Whether the rail pressure is controlled using the flow rate control valve 19, the pressure control valve 23, or a combination of these control valves is determined mainly depending on the operating state of the internal combustion engine. ing.

2. Control unit (ECU)
FIG. 2 is a functional block of a portion related to the idling stop control and the pressure control valve current value learning control at the idling stop in the control device 50 for controlling the accumulator fuel injection device 10 of the present embodiment. The example of a structure represented is shown. The control device 50 includes an idling stop control means 61, a target rail pressure calculation means 64, a rail pressure detection means 65, a flow control valve control means 66, a pressure control valve control means 67, and a fuel injection valve control means 68. And pressure control valve current value learning means 69 and the like. The control device 50 is mainly configured by a microcomputer having a known configuration, and each means is realized by execution of a program by the microcomputer.

  The control device 50 includes a rail pressure sensor 25, a fuel temperature sensor 24, a rotational speed sensor that detects an engine rotational speed Ne, a vehicle speed sensor that detects a vehicle speed V of the vehicle, an accelerator sensor that detects an operation amount Acc of an accelerator pedal, and a brake pedal. Various sensor signals such as a brake sensor for detecting the operation amount Br can be read. Further, the control device 50 is provided with a RAM (Random Access Memory) (not shown) for storing calculation results and detection results of the respective means.

  When the predetermined idling stop condition is satisfied, the idling stop control means 61 is provided for the fuel injection valve control means 68, the flow rate control valve control means 66, the pressure control valve control means 67, and the pressure control valve current value learning means 69. To send an idling stop condition satisfaction signal. Further, the idling stop control means 61, when a predetermined restart condition is satisfied while the internal combustion engine (not shown) is in the automatic stop state, the fuel injection valve control means 68, the flow rate control valve control means 66, and the pressure control valve control means 67. And a restart condition establishment signal is transmitted to the pressure control valve current value learning means 69.

  The idling stop condition is, for example, that the engine switch Sw is on, the detection position Sg of the gear sensor is neutral, the detection position Sb of the brake pedal sensor is stepped on, and the engine speed Ne is predetermined. However, the present invention is not limited to this. However, the present invention is not limited to this.

  The restart condition includes several conditions such as the detection position Sg of the gear sensor being released from the neutral state and the accelerator pedal Acc being depressed while the internal combustion engine (not shown) is in the automatic stop state. However, it is not limited to this.

  The target rail pressure calculation means 64 calculates the target rail pressure Ptgt based on the engine speed Ne, the accelerator operation amount Acc, and the like. The rail pressure detecting means 65 continuously reads the sensor signal Sp from the rail pressure sensor 25 and calculates the rail pressure Pr.

  The fuel injection valve control means 68 calculates the target fuel injection amount Qtgt based on the engine speed Ne, the accelerator operation amount Acc, and the like, and controls the fuel injection valve 17 corresponding to the target fuel injection amount Qtgt according to the rail pressure Pr. A signal is generated and a control signal is output to the fuel injection valve 17. The fuel injection valve control means 68 stops the fuel injection when receiving the idling stop condition satisfaction signal, and restarts the fuel injection when receiving the signal indicating that the restart condition is satisfied. In this embodiment, the fuel injection valve control means 68 is allowed to output a control signal to the fuel injection valve 17 when the rail pressure Pr is equal to or higher than the injectable pressure Pr_inj.

  The flow control valve control means 66 and the pressure control valve control means 67 basically execute energization control of the flow control valve 19 or the pressure control valve 23 so that the rail pressure Pr becomes the target rail pressure Ptgt. Specifically, the flow rate control valve control means 66 controls the flow rate of the fuel supplied to the pressurizing chamber 13a of the high pressure pump 13 by adjusting the opening degree of the flow rate control valve 19, and from the high pressure pump 13 to the common rail 15. The rail pressure Pr is adjusted by changing the flow rate of the high-pressure fuel to be pumped. Further, the pressure control valve control means 67 controls the flow rate of fuel discharged from the common rail 15 to the return passage 38 by adjusting the opening of the pressure control valve 23, thereby adjusting the rail pressure Pr.

  Further, the flow control valve control means 66 cuts off the power supply to the flow control valve 19 when receiving the idling stop condition establishment signal. Since the flow control valve 19 of the present embodiment has a normally open configuration, the flow control valve 19 is fully opened when the power is turned off.

  Further, when the pressure control valve control means 67 receives the idling stop condition establishment signal, the pressure control valve control means 67 controls the energization current value of the pressure control valve 23 to be the energization current value Ia when the idling stop condition is established. The energization current value Ia is a learned value of the energization current value when idling is stopped, which will be described later.

  As will be described later, the pressure control valve current value learning unit 69 performs processing for learning the optimum energization current value of the pressure control valve 23 when idling is stopped, and uses the learned value as the energization current learning value Ia of the pressure control valve 23. Is output to the pressure control valve control means 67.

3. Pressure control valve energization current value learning method Next, the pressure control valve energization current value learning process during idling stop control, which is executed by the control device 50 described above, is specifically described based on the flowcharts shown in FIGS. 3 to 6. Explained. This process is repeatedly executed at a predetermined cycle during operation of the internal combustion engine.

  When processing by the control device 50 is started, it is first determined whether or not idling stop control is being performed, that is, whether or not the engine is being stopped by idling stop control (step S102 in FIG. 3). If it is determined in step S102 that idling stop control is being performed (in the case of YES), the process proceeds to step S104. On the other hand, if it is determined that idling stop control is not in progress (in the case of NO), a main routine (not shown) is temporarily performed. Return.

  In step S104, it is determined whether or not a predetermined condition for learning the pressure control valve energization current value at the time of idling stop control is satisfied, and when it is determined that the predetermined condition is satisfied ( In the case of YES), the process proceeds to step S106. On the other hand, if it is determined that the predetermined condition is not satisfied (in the case of NO), the process temporarily returns to a main routine (not shown). Here, as the predetermined conditions, fuel temperature, rail pressure, engine cooling water temperature, and the like can be used, and these items and their values are determined by tests, simulations, and the like.

  In step S106, it is determined whether or not the current learning mode is a current reduction search mode described later. If it is determined that the current learning mode is a current reduction search mode (YES), the process proceeds to step S202 described later. If it is determined that the current reduction search mode is not set (NO), the process proceeds to step S108.

  In step S108, it is determined whether or not the current learning mode is a current increase search mode described later. If it is determined that the current learning mode is a current increase search mode (YES), the process proceeds to step S302 described later. When it is determined that the current increase search mode is not selected (NO), the process proceeds to step S110.

  In step S110, it is determined whether or not the current learning mode is a compromise current search mode described later. If it is determined that the current learning mode is a compromise current search mode (YES), the process proceeds to step S402 described later. If it is determined that the current mode is not the compromise current search mode (NO), the process proceeds to step S112.

  That is, if none of the current decrease search mode, current increase search mode, or compromise current search mode is selected (NO in steps S106 to S110), the process proceeds to step S112. Which learning mode is being executed? Can be determined by a flag.

  In step S112, whether there is a previous learning value, that is, whether the energization current of the pressure control valve 23 at the time of idling stop control has been learned in the past, and whether the learning value is stored in an appropriate storage area. Is determined. When there is no previous learning value (in the case of NO), the process proceeds to step 130, and the energization current value for closing the pressure control valve 23 is set as a default value. The PCV in steps S130 and S114 in FIG. 3 refers to the pressure control valve 23.

  Next, the process proceeds to step S132, where the amount of decrease in rail pressure is measured, and further proceeds to step S134, where it is determined whether the amount of decrease in rail pressure is greater than or equal to a predetermined value. Here, the predetermined value for the rail pressure drop amount can be determined as the rail pressure drop amount per unit time after the pressure control valve 23 is closed during the idling stop control. Further, the present invention is not limited to this, and the absolute value of the rail pressure after a certain time after the pressure control valve 23 is closed can be appropriately determined.

  When it is determined in step S134 that the rail pressure decrease amount is equal to or greater than the predetermined value (in the case of YES), fuel leaks from the pressure control valve 23 due to insufficient electromagnetic force to close the pressure control valve 23. Since there is a possibility that the current increase search mode is selected, the mode shifts to the current increase search mode (see step S136 in FIG. 3), and returns to the main routine (not shown).

  On the other hand, when it is determined in step S134 that the rail pressure decrease amount is less than the predetermined value (in the case of NO), the electromagnetic force for closing the pressure control valve 23 is sufficient, rather, the energization current value can be decreased. Since there is a possibility that it can be performed, the mode shifts to the current reduction search mode (see step S138 in FIG. 3), and returns to the main routine (not shown).

  In step S112, if there is a previous learning value of the energization current value of the pressure control valve 23 (in the case of YES), the process proceeds to step S114, and the energization current value for closing the pressure control valve 23 is set as the previous learning value. To do.

  Next, the process proceeds to step S116, where the amount of decrease in rail pressure is measured, and further proceeds to step S118, where it is determined whether the amount of decrease in rail pressure is greater than or equal to a predetermined value.

  When it is determined in step S118 that the rail pressure decrease amount is equal to or greater than the predetermined value (in the case of YES), the electromagnetic force for closing the pressure control valve 23 is insufficient as in the case of determining YES in step S134. As a result, there is a possibility that fuel is leaking from the pressure control valve 23, so that the mode is shifted to the current increase search mode (see step S136 in FIG. 3), and the process once returns to the main routine (not shown).

  On the other hand, when it is determined in step S118 that the rail pressure decrease amount is less than the predetermined value (in the case of NO), the process proceeds to step S120, and it is determined whether or not a predetermined period has elapsed since the previous learning. Here, the predetermined period from the previous learning can be, for example, the operating time of the internal combustion engine after the previous learning is completed. Alternatively, the number of executions of the idling stop control after the previous learning is completed or the execution time of the idling stop control can be appropriately determined.

  If it is determined in step S120 that the predetermined period has elapsed since the previous learning (in the case of YES), the electromagnetic force for closing the pressure control valve 23 is sufficient as in the case of determining NO in step S134. Rather, since there is a possibility that the energization current value can be reduced, the mode shifts to the current reduction search mode (see step S122 in FIG. 3), and returns to the main routine (not shown).

  On the other hand, when it is determined in step S120 that the predetermined period has not elapsed since the previous learning (in the case of NO), it is not necessary to perform learning again at this timing, and the process once returns to the main routine (not shown).

  If it is determined in step S106 that the current reduction search mode is set (YES), the process proceeds to step S202 in FIG. The processing content of the current decrease search mode after step S202 will be described below with reference to FIG.

  In step S202, the energization current value for closing the pressure control valve 23 is decreased by α1 (mA) from the previous value. The reduction amount α1 of the current value is appropriately determined by a test, simulation, or the like.

  Next, the process proceeds to step S204, where the amount of decrease in rail pressure is measured, and further proceeds to step S206, where it is determined whether the amount of decrease in rail pressure is greater than or equal to a predetermined value.

  If it is determined in step S206 that the rail pressure decrease amount is equal to or greater than the predetermined value (in the case of YES), the current step is performed even though the rail pressure decrease amount is less than the predetermined value before the shift to the current reduction search mode. In S202, the amount of decrease in the rail pressure is equal to or greater than the predetermined value by reducing the energization current value of the pressure control valve 23 by α1 (mA). Therefore, the previous value, that is, the energized current value before being decreased by α1 (mA) this time is set as the learned value in the current decrease search mode and stored in an appropriate storage area (see step S210 in FIG. 4). Next, in step S212, the current reduction search mode is ended, and the process once returns to the main routine (not shown).

  On the other hand, if it is determined in step S206 that the rail pressure decrease amount is less than the predetermined value (in the case of NO), the current reduction search mode is determined as a possibility that the energization current value of the pressure control valve 23 may be further reduced. (See step S208 in FIG. 4) and once returns to the main routine (not shown).

  As a result of the processing in the current reduction search mode described above, the energization current value of the pressure control valve 23 during idling stop control is prevented from becoming larger than necessary, and the power consumption of the battery can be minimized. .

  If it is determined in step S108 of FIG. 3 that the current increase search mode is set (YES), the process proceeds to step S302 of FIG. The processing content of the current increase search mode after step S302 will be described below with reference to FIG.

  In step S302, when the energization current value of the pressure control valve 23 is increased by β (mA) from the previous value, it is determined whether or not the current value is equal to or greater than a predetermined limit value described later. If it is equal to or greater than the limit value (in the case of YES), the process proceeds to step S320. If it is less than the limit value (in the case of NO), the process proceeds to step S304.

  In step S304, the energization current value for closing the pressure control valve 23 is increased by β (mA) from the previous value. The increase amount β of the current value is appropriately determined by a test, simulation, or the like.

  Next, the process proceeds to step S306, where the amount of decrease in rail pressure is measured, and further proceeds to step S308, where it is determined whether the amount of decrease in rail pressure is greater than or equal to a predetermined value.

  When it is determined in step S308 that the rail pressure decrease amount is less than the predetermined value (in the case of NO), in step S304, the energizing current value of the pressure control valve 23 is increased by β (mA), so that the rail pressure decrease amount is predetermined. Therefore, the current value, that is, the energized current value increased by β (mA) this time, is used as a learning value in the current increase search mode, and is stored in an appropriate storage area (see FIG. 5). Step S310). Next, in step S312, the current reduction search mode is terminated, and the process once returns to the main routine (not shown).

  On the other hand, if it is determined in step S308 that the rail pressure drop amount is equal to or greater than the predetermined value (in the case of YES), the electromagnetic force for closing the pressure control valve 23 is still insufficient, so that the pressure control valve 23 Since there is a possibility that fuel has leaked, the current increase search mode is continued (see step S314 in FIG. 5), and the process once returns to the main routine (not shown).

  As a result of the processing in the current increase search mode described above, an increase in the energization current value of the pressure control valve 23 for making the amount of decrease in rail pressure during idling stop control less than a predetermined value may be minimized. Battery power consumption can be minimized.

  If it is determined in step S302 that the current value is equal to or greater than the predetermined limit value (YES), the process proceeds to step S320, and whether there is a compromise current learning value to be described later, that is, a compromise current learning mode to be described later. The compromise current learning is performed in the past, and it is determined whether or not the learning value is stored in an appropriate storage area (see step S320 in FIG. 5).

  Here, the compromise current learning mode will be described. If the rail pressure drop during idling stop control is greater than or equal to the predetermined value (YES in steps S134 and S118 in FIG. 3), the electromagnetic force for closing pressure control valve 23 is insufficient. As described above, it is assumed that there is a possibility that the fuel leaks from the pressure control valve 23 due to the presence of the current, and the shift to the current increase search mode is performed as described above. However, even a small amount of fuel leaks in the injector 17 and the high-pressure pump 13, and the cause of the rail pressure drop amount at the idling stop control exceeding a predetermined value is caused by leaks from places other than these pressure control valves 23. If this is the case, the rail pressure drop cannot be suppressed even if the current value supplied to the pressure control valve 23 is increased, but rather the power consumption of the battery is wasted. Therefore, a predetermined limit value is provided for the energization current value to be increased in the current increase search mode, and when the energization current value exceeds the predetermined limit value, the energization current value is decreased stepwise and the electromagnetic force is decreased. Thus, the energization current value immediately before the amount of decrease in rail pressure is increased as the compromise current learning value.

  Returning to the description of FIG. 5, if there is no compromise current learning value (NO) in step S320, the mode is shifted to the compromise current search mode, and the process once returns to the main routine (not shown). (Refer to step S324 in FIG. 5).

  On the other hand, in step S320, if there is a compromise current learning value (in the case of YES), it is determined whether or not a predetermined period has elapsed since the previous compromise current learning (see step S322 in FIG. 5). Here, the predetermined period from the previous compromise current learning can be, for example, the operating time of the internal combustion engine after the previous compromise current learning ends. Alternatively, the number of executions of the idling stop control or the execution time of the idling stop control after the previous compromise current learning is completed can be appropriately determined.

  If it is determined in step S322 that the predetermined period has elapsed since the previous compromise current learning (in the case of YES), the process proceeds to the compromise current search mode as in the case of NO in step S320 (step in FIG. 5). (See S324), and returns to the main routine (not shown).

  On the other hand, if it is determined in step S322 that the predetermined period has not elapsed since the previous compromise current learning (in the case of NO), it is not necessary to perform the compromise current learning again at this timing, and the process goes to a main routine (not shown). Return once.

  Next, the processing content of the compromise current search mode will be described below with reference to FIG. If it is determined in step S110 of FIG. 3 that the compromise current search mode is set (YES), the process proceeds to step S402 and subsequent steps in FIG.

  In step S402, the energization current value for closing the pressure control valve 23 is decreased by α2 (mA) from the previous value. The reduction amount α2 of the current value is appropriately determined by a test, simulation, or the like.

  Next, the process proceeds to step S404, where the amount of decrease in rail pressure is measured, and further proceeds to step S406, where it is determined whether the amount of decrease in rail pressure exceeds the previous time.

  When it is determined in step S406 that the rail pressure decrease amount has exceeded the previous time (in the case of YES), the rail pressure decrease amount has been reduced to the previous time by reducing the energization current value of the pressure control valve 23 by α2 (mA) in step S402. Therefore, the previous value, that is, the energized current value before being decreased by α2 (mA) this time is used as the learned value in the compromise current search mode, and is stored in an appropriate storage area (step S408 in FIG. 6). reference). Next, in step S410, the compromise current search mode is terminated, and the process once returns to the main routine (not shown).

  On the other hand, if it is determined in step S406 that the rail pressure decrease amount does not exceed the previous time (in the case of NO), it is possible that the energization current value of the pressure control valve 23 may be further reduced. The search mode is continued (see step S412 in FIG. 6), and the process once returns to the main routine (not shown).

  As a result of the processing in the compromise current search mode described above, the factor that the rail pressure decrease amount during the idling stop control becomes a predetermined value or more is caused by the fuel leak from the injector 17 or the high-pressure pump 13 instead of the pressure control valve 23. Even if it is a thing, the energization current value of the pressure control valve 23 at the time of idling stop control can be minimized, and the power consumption of the battery can be minimized.

  The predetermined value in the step (S118, S134, S206, S308) for determining whether or not the rail pressure decrease amount is equal to or greater than a predetermined value is the rail pressure decrease amount per unit time or the pressure control valve 23 is closed. As described above, the absolute value of the rail pressure after a certain period of time after the valve can be determined as appropriate, but the predetermined value in each step can be the same value or appropriate in each step. A value can also be defined.

  Further, as described above, the values of α1 and α2 that are reduction amounts of the energization current value in steps S202 and S402, or β that is the increase amount of the energization current value in step S302 can be determined as appropriate by simulation. However, the values of α1, α2, and β can be the same or appropriate values can be determined.

  Further, as described above, the predetermined period in step S120 and step S322 can be determined as appropriate, but the predetermined period in each step can be the same or an appropriate value can be determined.

As described above, according to the control device and control method of the accumulator type fuel injection device and the accumulator type fuel injection device of the present embodiment, based on the pressure drop amount in the common rail during the automatic stop of the internal combustion engine by the idling stop control. By learning the energization current value of the pressure control valve during the automatic stop, the power consumption of the battery for the operation of the pressure control valve during the idling stop control can be minimized. Further, even when the electromagnetic force of the pressure control valve is insufficient due to deterioration of the pressure control valve over time, the energization current value can be increased, and the increase amount can be minimized. Furthermore, even when a pressure drop of a predetermined amount or more occurs due to factors other than the pressure control valve, the optimum value of the pressure control valve energization current can be learned.

  Further, according to the control device and control method of the pressure accumulation type fuel injection device and the pressure accumulation type fuel injection device of the present embodiment, during idling stop control, when the pressure drop amount is less than a predetermined value, the energization current value is decreased. When the pressure drop amount is greater than or equal to a predetermined value, the energizing current value is increased to learn the energizing current value of the pressure control valve, so that the electromagnetic force required to close the pressure control valve is more than necessary. In both cases where the pressure control valve current is large or insufficient, the optimum value of the pressure control valve energization current can be learned.

In addition, according to the control device and control method of the pressure accumulation type fuel injection device and the pressure accumulation type fuel injection device of the present embodiment, when the energization current value of the pressure control valve is increased, the increased energization current value is a predetermined limit. When the value exceeds the value, the energization current value is decreased step by step, and when the pressure drop after the decrease exceeds the previous pressure drop, the previous energization current value is used as the learning value. Even when the pressure drop more than the value is caused by factors other than the pressure control valve, the optimum value of the pressure control valve energization current can be learned.

1: Fuel tank, 10: Accumulated fuel injection device, 11: Low pressure pump, 13: High pressure pump, 13a: Pressurization chamber, 14: Cam, 15: Common rail, 17: Fuel injection valve, 19: Flow control valve, 23 : Pressure control valve, 24: Fuel temperature sensor, 25: Rail pressure sensor, 27: Fuel intake valve, 28: Fuel discharge valve, 29: Plunger, 31: Low pressure fuel passage, 33, 35: High pressure fuel passage, 37, 38 , 39: return passage, 50: control device, 61: idling stop control means, 64: target rail pressure calculation means, 65: rail pressure detection means, 66: flow control valve control means, 67: pressure control valve control means, 68 : Fuel injection valve control means, 69: Pressure control valve current value learning means

Claims (5)

A common rail that accumulates fuel pumped by a high-pressure pump;
A pressure control valve for adjusting the pressure in the common rail and having a normally open type structure that opens the fuel passage in a non-energized state;
A fuel injection valve that is connected to the common rail and injects the fuel into a cylinder of an internal combustion engine;
A control device for controlling an accumulator fuel injection device comprising:
An idling stop control means for automatically stopping and restarting the internal combustion engine;
Pressure control valve energization current value learning means for learning the energization current value of the pressure control valve during the automatic stop based on the pressure drop amount in the common rail during the automatic stop;
A control apparatus for an accumulator fuel injection apparatus, comprising: The pressure control valve energization current value learning means includes:
When the pressure drop amount is less than a predetermined value, while reducing the energization current value,
By increasing the energization current value when the amount of pressure drop is a predetermined value or more,
2. The control device for an accumulator fuel injection device according to claim 1, wherein an energization current value of the pressure control valve is learned. The pressure control valve energization current value learning means includes:
When increasing the energizing current value, when the increased energizing current value exceeds the specified limit value, the energizing current value is decreased stepwise, and the pressure drop after the decrease exceeds the previous pressure drop. 3. The control apparatus for an accumulator fuel injection apparatus according to claim 2, wherein the previous energization current value is used as a learning value. An accumulator fuel injection device comprising the control device according to claim 1. A common rail that accumulates fuel pumped by a high-pressure pump;
A pressure control valve for adjusting the pressure in the common rail and having a normally open type structure that opens the fuel passage in a non-energized state;
A fuel injection valve that is connected to the common rail and injects the fuel into a cylinder of an internal combustion engine;
A control method for controlling an accumulator fuel injection device comprising:
During idling stop control for automatically stopping and restarting the internal combustion engine,
A control method for an accumulator fuel injection device, wherein an energization current value of a pressure control valve during the automatic stop is learned based on a pressure drop amount in the common rail during the automatic stop.

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