JP2012225327A - Method for controlling common rail fuel injection device and common rail fuel injection device using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a common rail fuel injection device and a method for controlling the same that can learn a response error of a supply pump without causing a large increase in a fuel pressure in a common rail.SOLUTION: In the common rail fuel injection device, operation of a decompression means is prohibited so as to prohibit fuel in the common rail from being discharged, and the supply pump and a PCV are actuated while setting a timing, at which a discharge amount control valve (PCV) of the supply pump to the common rail is closed, so that the timing gradually advances from a predetermined initial value at which fuel pumping is not executed. As a result, when an internal pressure in the common rail significantly increases, a pump closing timing set before is defined as an actual non-pumping timing, and the response error of the supply pump is learned based on a difference between a non-pumping timing regarding a standard model of the supply pump and the actual non-pumping timing.

Description

  The present invention relates to a control method for a common rail fuel injection device and a common rail fuel injection device using the method. More specifically, the present invention relates to a method for accurately learning the responsiveness of an actuator of a fuel pump in a common rail fuel injection device and a common rail fuel injection device to which the method is applied.

  In the common rail type fuel injection device, for example, a calibration value set in advance for a standard (model) supply pump is prepared for responsiveness such as an increase rate of fuel pressure in the common rail with respect to a control input value to the supply pump. Is done. The calibration value is compared with the actual response to the control input value to the supply pump, and the basic control characteristic value of the supply pump is calibrated in accordance with the amount of deviation between the calibration value and the actual response.

  In the prior art, for example, when fuel injection is stopped during deceleration, the control input value to the supply pump is changed, and the increase rate of the fuel pressure in the common rail with respect to the change in the control input value is calculated. It has been proposed to calibrate the basic control characteristic value of the supply pump in accordance with the amount of deviation between the increase rate and the increase rate derived based on the preset calibration value for the standard supply pump ( For example, see Patent Document 1).

  As described above, in the prior art, the basic control characteristic value is calibrated by increasing the fuel pressure in the common rail by changing the control input value to the supply pump. However, for example, when fuel injection is restarted during calibration, if the injector that injects fuel into the combustion chamber is controlled as usual, the fuel pressure in the common rail is high, and the fuel injection amount increases. As a result, unintended effects such as an increase in torque generated by the engine occur.

  Therefore, in the invention described in Patent Document 1 described above, when the fuel injection returns during calibration, the injector control pulse is set by a correction pulse width set in advance corresponding to the increase in the fuel pressure in the common rail. Correction to reduce the pulse width is performed so that the same injection amount as that in the normal state where the fuel pressure is not increased is obtained.

  As described above, in the prior art, when the fuel injection returns while the fuel pressure in the common rail is rising, the normal state of the fuel injection amount is maintained by operating the control pulse of the injector. ing. However, the inconvenience caused when the fuel injection is restarted while the fuel pressure is increasing is not limited to the increase in the fuel injection amount. For example, the following other inconvenience may occur. There is.

  First, when the fuel pressure in the common rail becomes higher than the target value, it becomes easy to take in air. As a result, the combustion time is shortened and the combustion noise is increased. Further, the adhesion of fuel to the inner wall surface of the combustion chamber increases, and the hydrocarbon (HC) in the exhaust gas increases. Furthermore, due to the increase in fuel adhesion to the inner wall surface of the combustion chamber, the engine oil is diluted, the viscosity of the engine oil is lowered, and the lubrication performance is lowered.

  As described above, in this technical field, not only an unintended increase in torque, but also an increase in combustion noise, an increase in HC in exhaust gas, and dilution of engine oil cause problems such as dilution of engine oil. There is a continuing need for techniques that allow the supply pump basic control characteristic values to be calibrated without significant increases.

Japanese Patent Application Laid-Open No. 6-200849

  As described above, in this technical field, not only an unintended increase in torque, but also an increase in combustion noise, an increase in HC in exhaust gas, and a decrease in fuel pressure in the common rail that causes inconveniences such as engine oil dilution. There is a continuing need for techniques that allow the supply pump basic control characteristic values to be calibrated without significant increases.

  The present invention has been made to meet such a demand. More specifically, the present invention relates to a control method for a common rail fuel injection device capable of learning a response error of a supply pump without significantly increasing the fuel pressure in the common rail, and a common rail type using the same method. An object is to provide a fuel injection device.

The above object of the present invention is to
A common rail,
A supply pump for supplying pressurized fuel to the common rail;
A discharge amount control valve provided in the supply pump;
A pump closing timing control means for controlling a pump closing timing which is a timing for closing the discharge amount control valve;
Common rail internal pressure detection means for detecting the common rail internal pressure which is the pressure in the common rail;
Pressure reducing means for reducing the pressure in the common rail by discharging the fuel in the common rail;
Decompression means control means for controlling the operation of the decompression means;
In a common rail fuel injection device comprising:
A pressure reducing means operation prohibiting step for prohibiting the operation of the pressure reducing means and prohibiting the discharge of fuel in the common rail;
A pump closing timing setting step for setting the pump closing timing to a predetermined initial value at which the pumping of fuel does not occur, by the pump closing timing control means;
A fuel pumping step of operating the supply pump and the discharge amount control valve at a set pump closing time;
A pressure change determination step for determining whether or not the difference between the common rail internal pressures detected by the pressure detection means before and after the fuel pumping step is greater than or equal to a predetermined minimum pressure change amount; and
If the determination result in the pressure change determination step is negative, the pump closing timing is set by advancing and setting the pump closing timing by a predetermined increment, and the processing flow is returned to the fuel pumping step. When,
If the determination result in the pressure change determination step is affirmative, the previously set pump closing timing is set as the actual no-pressure feeding timing, and the model no-pressure feeding timing, which is the no-pressure feeding timing for the standard model of the supply pump, A pump closing timing learning step for obtaining a difference with the pumping timing and correcting a learning value of the pump closing timing based on the difference;
It is achieved by the control method of a common rail type fuel injection device characterized by including.

Also, the above object of the present invention is to
A common rail,
A supply pump for supplying pressurized fuel to the common rail;
A discharge amount control valve provided in the supply pump;
A pump closing timing control means for controlling a pump closing timing which is a timing for closing the discharge amount control valve;
Common rail internal pressure detection means for detecting the common rail internal pressure which is the pressure in the common rail;
Pressure reducing means for reducing the pressure in the common rail by discharging the fuel in the common rail;
Decompression means control means for controlling the operation of the decompression means;
In a common rail fuel injection device comprising:
The pressure reducing means control means prohibits the operation of the pressure reducing means to prohibit the discharge of fuel in the common rail;
The pump closing timing control means sets the pump closing timing to a predetermined initial value at which fuel pumping does not occur;
The supply pump and the discharge amount control valve are operated at a set pump closing timing;
When the difference between the common rail internal pressures detected by the pressure detection means before and after the operation of the supply pump and the discharge amount control valve is smaller than a predetermined minimum pressure change amount, the pump closing timing control means The closing timing is set by advancing in a predetermined increment, the operation is returned to the operation of the supply pump and the discharge amount control valve according to the set pump closing timing, and the supply pump and the discharge amount control valve When the difference between the common rail internal pressures detected by the pressure detecting means before and after the operation is larger than a predetermined minimum pressure change amount, the previously set pump closing timing is set as the actual no-pressure feeding timing, and the supply pump Model no-pressure feeding time and actual no-pressure feeding time Obtaining the difference with the period, and correcting the learning value of the pump closing time based on the difference,
It is also achieved by a common rail fuel injection device characterized by performing a series of processes including

  As described above, in the control method of the common rail fuel injection device according to the present invention, the timing for closing the discharge amount control valve (PCV) of the supply pump is set to a predetermined initial value at which fuel pumping does not occur. Thereafter, the timing for closing the PCV is set by gradually advancing at a predetermined increment. Then, the difference between the “time to close the PCV” (actual no-pressure feeding time) immediately before the fuel pumping occurs and the no-pressure feeding time (model no-pressure feeding time) for the standard model of the supply pump is obtained. Based on this, the response error of the supply pump is learned. As a result, the response error of the supply pump is learned without significantly increasing the fuel pressure in the common rail, the common rail type fuel injection device is controlled accurately, and an appropriate amount of fuel is supplied to the common rail at an appropriate timing. Can be supplied to.

It is a flowchart showing a series of processes performed in the control method of the common rail type fuel injection device concerning one embodiment of the present invention. It is a graph which represents typically the relationship between the pump closing timing and the amount of fuel pumping in the control method of the common rail type fuel injection device concerning one embodiment of the present invention.

  As described above, the present invention relates to a control method for a common rail fuel injection device capable of learning a response error of a supply pump without significantly increasing the fuel pressure in the common rail, and a common rail fuel using the same method. It aims at providing an injection device.

  As a result of diligent research to achieve the above object, the present inventor, in a common rail type fuel injection device, prohibits the operation of the pressure reducing means, prohibits the discharge of fuel in the common rail, and controls the discharge amount of the supply pump to the common rail. When the supply pump and PCV are operated while the valve (PCV) closing timing is set by gradually advancing from a predetermined initial value at which fuel pumping does not occur, and when the common rail internal pressure rises significantly due to these operations In addition, the previously set pump closing timing is set as the actual no-pressure feeding timing, and the response error of the supply pump is learned based on the difference between the no-pressure feeding timing for the standard model of the supply pump and the actual no-pressure feeding timing. To accurately control the fuel injection system and supply an appropriate amount of fuel into the common rail at an appropriate timing. Which has led to the arrival.

That is, the first aspect of the present invention is:
A common rail,
A supply pump for supplying pressurized fuel to the common rail;
A discharge amount control valve provided in the supply pump;
A pump closing timing control means for controlling a pump closing timing which is a timing for closing the discharge amount control valve;
Common rail internal pressure detection means for detecting the common rail internal pressure which is the pressure in the common rail;
Pressure reducing means for reducing the pressure in the common rail by discharging the fuel in the common rail;
Decompression means control means for controlling the operation of the decompression means;
In a common rail fuel injection device comprising:
A pressure reducing means operation prohibiting step for prohibiting the operation of the pressure reducing means and prohibiting the discharge of fuel in the common rail;
A pump closing timing setting step for setting the pump closing timing to a predetermined initial value at which the pumping of fuel does not occur, by the pump closing timing control means;
A fuel pumping step of operating the supply pump and the discharge amount control valve at a set pump closing time;
A pressure change determination step for determining whether or not the difference between the common rail internal pressures detected by the pressure detection means before and after the fuel pumping step is greater than or equal to a predetermined minimum pressure change amount; and
If the determination result in the pressure change determination step is negative, the pump closing timing is set by advancing and setting the pump closing timing by a predetermined increment, and the processing flow is returned to the fuel pumping step. When,
If the determination result in the pressure change determination step is affirmative, the previously set pump closing timing is set as the actual no-pressure feeding timing, and the model no-pressure feeding timing, which is the no-pressure feeding timing for the standard model of the supply pump, A pump closing timing learning step for obtaining a difference with the pumping timing and correcting a learning value of the pump closing timing based on the difference;
Is a control method for a common rail fuel injection device.

  The common rail is also referred to as a “pressure accumulation chamber” and is mainly mounted on a diesel engine. The common rail is a pressure vessel that stores ultra-high pressure (for example, 1800 atm) fuel therein. High-precision fuel injection is realized by temporarily storing ultra-high pressure fuel in such a common rail and injecting the fuel into the combustion chamber via fuel injection means such as an injector, for example. Thereby, for example, reduction of particulate matter (PM) such as black smoke and nitrogen oxide (NOx), improvement of fuel consumption and torque, reduction of noise and vibration, and the like are achieved. A common rail comprises a fuel injection system with an injector, a supply pump mentioned later, etc.

  The supply pump includes, for example, a drive shaft drivingly connected to a crankshaft of an engine, a cam fixed to the drive shaft, a cylinder, a plunger that slides in the cylinder while being in contact with the cam, and fuel from a fuel tank A discharge control valve (PCV) that opens and closes communication between the suction passage and the plunger chamber (pressure chamber) in the cylinder, and opens and closes communication between the fuel supply passage to the common rail and the plunger chamber (pressure chamber) in the cylinder. A delivery valve is provided.

  When the plunger slides in the direction in which the plunger chamber (pressure chamber) in the cylinder expands with the rotation of the cam in the state where the PCV is opened, for example, the plunger chamber (pressurization) via a feed pump (low pressure pump) The fuel is sucked into the chamber. On the other hand, when the plunger slides in the direction in which the plunger chamber (pressurizing chamber) in the cylinder narrows as the cam rotates with the PCV closed, the fuel in the plunger chamber (pressurizing chamber) is pressurized and delivered. The valve is opened, and the fuel in the plunger chamber (pressurizing chamber) is supplied to the common rail.

  Therefore, if the timing of closing the PCV is delayed when the plunger slides in the direction in which the pressurizing chamber is narrowed, the fuel in the pressurizing chamber is not sufficiently pressurized, and as a result, an appropriate amount of fuel is delivered at an appropriate timing. No pressure is supplied to the common rail, and eventually no pressure is supplied and no fuel is supplied. Conversely, if the PCV is closed so that the PCV is closed at an appropriate timing for the plunger to slide in the direction in which the pressurizing chamber is narrowed, an appropriate amount of fuel is supplied to the common rail at an appropriate timing. Will come to be. However, if the PCV closes too early, the PCV closes when the plunger slides in the direction in which the pressurizing chamber expands, and a sufficient amount of fuel cannot be sucked into the pressurizing chamber.

  As described above, in order to supply an appropriate amount of fuel into the common rail at an appropriate timing, it is necessary to accurately control the timing of closing the PCV (pump closing timing). Therefore, in the prior art, as described above, the correspondence relationship between the control input value of the pump closing timing and the pumping amount of fuel (the increase rate of the fuel pressure) is acquired in advance for the standard supply pump, and the correspondence relationship is obtained. The calibration value for the supply pump, which is a standard model, is set based on this, and based on the calibration value, the precise control of the fuel pumping amount by the control input value in the actual supply pump is attempted. Was common.

  However, in reality, the responsiveness of individual supply pumps does not completely match the responsiveness of the supply pump as a standard model due to variations in manufacturing quality and changes over time. There is a deviation (response error) between the actual response of the supply pump to the control input value based on it and the response of the standard supply pump. Therefore, in order to accurately control the common rail fuel injection device and supply an appropriate amount of fuel into the common rail at an appropriate timing, the basic control characteristic value of the actual supply pump is determined based on this response error. It needs to be calibrated.

  However, as described above, in the conventional technique, when the basic control characteristic value of the supply pump is calibrated, the fuel pressure in the common rail is greatly increased, and as a result, not only an unintended increase in torque, Inconveniences such as increased combustion noise, increased HC in exhaust gas, and dilution of engine oil. Therefore, in this embodiment, there is provided a method capable of calibrating the basic control characteristic value of the supply pump without significantly increasing the fuel pressure in the common rail that causes such inconvenience (for details). Will be described later). The above description merely illustrates the configuration and operation of the supply pump including the discharge amount control valve (PCV), and the configuration and operation of the supply pump are not limited to the above description.

  As described above, the pump closing timing control means controls the pump closing timing, which is the timing for closing the discharge amount control valve (PCV). For example, when the discharge amount control valve (PCV) is a normally open type electromagnetic discharge amount control valve having a valve body, a spring, and an electromagnetic coil, the PCV is supplied to the electromagnetic coil by the pump closing timing control means. By energization, the valve body is moved against the urging force of the spring from the normal valve open state to shift to the valve closed state. In this way, the pump closing timing control means can control the pump closing timing, which is the timing for closing the discharge amount control valve (PCV). However, the above description only illustrates one aspect of the pump closing timing control means, and the configuration of the pump closing timing control means is not limited to the above description.

  The common rail internal pressure detecting means detects the common rail internal pressure, which is the pressure in the common rail, as described above. The common rail internal pressure detecting means is not limited to a specific method, and various types of pressure sensors (for example, a capacitance pressure sensor, a semiconductor pressure sensor, etc.) widely used in the technical field. It can be set as the structure containing. The common rail internal pressure detecting means detects the pressure of the fuel in the common rail, generates a measurement signal (detection signal) indicating the pressure, and sends the signal to, for example, an electronic control unit (ECU). It may be configured as follows.

  As described above, the pressure reducing means lowers the pressure in the common rail by discharging the fuel in the common rail. The pressure reducing means may be, for example, a pressure reducing valve interposed in a pipe that discharges fuel from the common rail to the fuel tank. Further, the decompression unit may be configured to open and close in accordance with a control signal (instruction signal) sent from an electronic control unit (ECU), for example.

  The electronic control unit (ECU) includes, for example, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). An electronic device mainly composed of a known microcomputer including a storage device such as a nonvolatile memory and an interface. However, the above description regarding the ECU is merely an example, and the configuration of the ECU is not limited to the above description.

  The decompression means control means controls the operation of the decompression means as described above. For example, as described above, when the decompression unit is configured to open and close in response to a control signal (instruction signal) sent from the ECU, the decompression unit control unit includes a ROM or a RAM provided in the ECU. It may be implemented as an algorithm described as a program that defines a process that is stored in a storage device and executed by a CPU provided in the ECU.

As described above, the control method of the common rail fuel injection device according to the present embodiment is the common rail fuel injection device including the above components.
A pressure reducing means operation prohibiting step for prohibiting the operation of the pressure reducing means and prohibiting the discharge of fuel in the common rail;
A pump closing timing setting step for setting the pump closing timing to a predetermined initial value at which the pumping of fuel does not occur, by the pump closing timing control means;
A fuel pumping step of operating the supply pump and the discharge amount control valve at a set pump closing time;
A pressure change determination step for determining whether or not the difference between the common rail internal pressures detected by the pressure detection means before and after the fuel pumping step is greater than or equal to a predetermined minimum pressure change amount; and
If the determination result in the pressure change determination step is negative, the pump closing timing is set by advancing and setting the pump closing timing by a predetermined increment, and the processing flow is returned to the fuel pumping step. When,
If the determination result in the pressure change determination step is affirmative, the previously set pump closing timing is set as the actual no-pressure feeding timing, and the model no-pressure feeding timing, which is the no-pressure feeding timing for the standard model of the supply pump, A pump closing timing learning step for obtaining a difference with the pumping timing and correcting a learning value of the pump closing timing based on the difference;
including.

  In the pressure reducing means operation prohibiting step, as described above, the operation of the pressure reducing means is prohibited and the discharge of fuel in the common rail is prohibited. This is because, in the control method for the common rail fuel injection device according to the present embodiment, the responsiveness of the supply pump (the discharge amount control valve (PCV) included) is detected based on the pressure of the fuel in the common rail. This is because if the pressure reducing means is operated and the pressure in the common rail fluctuates, the response of the supply pump cannot be detected correctly.

  In the pump closing timing setting step, as described above, the pump closing timing control means sets the pump closing timing to a predetermined initial value at which fuel pumping does not occur. This is because, in the control method of the common rail fuel injection device according to the present embodiment, the supply pump has a discharge amount at the pump closing time (no-pressure feeding time) immediately before the fuel pump starts to pump from the supply pump to the common rail. This is because the learning value of the pump closing timing is corrected based on the difference between the standard model of the control valve (PCV) and the actual supply pump.

  Since there is a possibility that the actual non-feeding timing in the supply pump is more retarded than the non-feeding timing assumed in the standard model (model non-feeding timing), the initial value is, for example, the standard model of the supply pump. It is desirable to set a certain margin on the retard side with respect to the model no-pressure feeding time, which is the no-pressure feeding time.

  In the fuel pumping step, as described above, the supply pump and the discharge amount control valve are operated at the set pump closing timing. Specifically, in the fuel pumping step, the supply pump and the discharge amount control valve are operated at the pump closing timing set to the initial value in the pump closing timing setting step. As described above, the initial value corresponds to, for example, the pump closing timing that is on the retard side of the model no-pressure feeding timing that is the no-pressure feeding timing for the standard model of the supply pump. That is, when the pump closing timing is set to the initial value, even if the supply pump and the discharge amount control valve are operated, the fuel is not pumped from the supply pump to the common rail.

  However, as will be described in detail later, if the pump closing timing is gradually advanced by a predetermined increment in the pump closing timing resetting step, the pump closing timing eventually reaches the non-pressure feeding timing, Thereafter, when the supply pump and the discharge amount control valve are operated at the set pump closing timing, an amount of fuel corresponding to the set pump closing timing is pumped from the supply pump into the common rail.

  Next, in the pressure change determining step, as described above, whether or not the difference between the common rail internal pressures detected by the pressure detecting means before and after the fuel pumping step is greater than or equal to a predetermined minimum pressure change amount. Determine whether. That is, when fuel is pumped from the supply pump into the common rail in the fuel pumping step, the pressure in the common rail increases according to the amount of fuel pumped. Therefore, it is possible to determine whether or not fuel is pumped from the supply pump into the common rail in the fuel pumping step based on the difference (variation) in the common rail internal pressure before and after the fuel pumping step.

  The above determination should be made on the basis of a significant difference in the common rail internal pressure before and after the fuel pumping step in consideration of detection error of the pressure detection means and detection signal noise. Therefore, in the pressure change determination step, it is determined whether or not the difference between the common rail internal pressures detected by the pressure detection means before and after the fuel pumping step is equal to or greater than a predetermined minimum pressure change amount. That is, the minimum pressure change amount is a threshold value for determining whether or not the difference in the common rail internal pressure before and after the fuel pumping step is significant, taking into account the detection error of the pressure detection means and the noise of the detection signal. To be predetermined.

  Next, when the determination result in the pressure change determination step is negative, that is, when the difference in the common rail internal pressure before and after the fuel pumping step is less than the minimum pressure change amount, the pump closing timing resetting step is executed. . In the pump closing timing resetting step, as described above, the pump closing timing is set to advance by a predetermined increment, and the flow of processing is returned to the fuel pressure feeding step.

  In order to improve the learning accuracy of the pump closing timing, the increment is preferably set to a smaller value. However, as the increment becomes smaller, even if the common rail internal pressure increases due to the advance angle of the pump closing timing, the increase width becomes smaller. As a result, when the increase width of the common rail internal pressure due to the advance angle at the pump closing timing is less than the above-described minimum pressure change amount, even if the common rail internal pressure actually increases due to the advance angle at the pump close timing, the pressure change determining step Therefore, it is determined that the common rail internal pressure is not increased due to the advance angle of the pump closing timing. Therefore, the increment may be set in advance in consideration of, for example, the learning accuracy of the pump closing timing, the detection error of the pressure detection means, the noise of the detection signal, and the like.

  As described above, when the determination result in the pressure change determination step is negative, the pump closing timing resetting step is executed, the pump closing timing is advanced by a predetermined increment, and the processing to the fuel pumping step is performed. Is returned. Then, at the pump closing timing advanced by the increment in the pump closing timing resetting step, the supply pump and the discharge amount control valve are operated, and as a result, fuel is pumped from the supply pump into the common rail. No is determined again in the pressure change determination step. These pump closing timing resetting step, fuel pumping step, and pressure change determining step are performed until the determination result in the pressure change determining step becomes affirmative, that is, the fuel is pumped from the supply pump into the common rail in the fuel pumping step. Repeat until it is determined.

  On the other hand, if the determination result in the pressure change determination step is affirmative, that is, if the difference between the common rail internal pressures before and after the fuel pumping step is equal to or greater than the minimum pressure change amount, the pump closing timing learning step is executed. In the pump closing timing learning step, as described above, the previously set pump closing timing is set as the actual no-pressure feeding timing, and the model no-pressure feeding timing, which is the no-pressure feeding timing for the standard model of the supply pump, and the actual no-pressure feeding The difference with the time is obtained, and the learning value of the pump closing time is corrected based on the difference.

  More specifically, the difference in the common rail internal pressure before and after the fuel pumping step is equal to or greater than the minimum pressure change amount, that is, the supply pump and the discharge amount control valve are set at the pump closing timing set this time in the fuel pumping step. As a result of the operation, it is determined in the pressure change determination step that the fuel is pumped from the supply pump into the common rail. Therefore, in the pump closing timing learning step, the pump closing timing set immediately before is set as the actual no-pressure feeding timing, not the pump closing timing set this time. The actual non-pressure feeding time is the non-pressure feeding time in the actual supply pump, and may differ from the non-pressure feeding time (model no-pressure feeding time) assumed based on the calibration value for the standard model.

  In other words, the response of the actual supply pump with respect to the pump closing time does not necessarily match the response with respect to the pump closing time in the standard model. Therefore, in the pump closing timing learning step, the difference between the model no-pressure feeding timing, which is the no-pressure feeding timing for the standard model of the supply pump, and the actual no-pressure feeding timing is obtained, and the basic about the pump closing timing is determined based on the difference. The learning value of the control characteristic is corrected.

  Note that the algorithm corresponding to the series of processes may be implemented as a program that defines a process that is stored in a storage device such as a ROM or a RAM included in the ECU and executed by a CPU included in the ECU.

  As described above, in the control method for the common rail fuel injection device according to this embodiment, the timing for closing the discharge amount control valve (PCV) of the supply pump is set to a predetermined initial value at which no fuel is pumped. After that, the timing for closing the PCV is gradually advanced by a predetermined increment. Then, the difference between the “time to close the PCV” (actual no-pressure feeding time) immediately before the fuel pumping occurs and the no-pressure feeding time (model no-pressure feeding time) for the standard model of the supply pump is obtained. Based on this, the response error of the supply pump is learned. As a result, the response error of the supply pump is learned without significantly increasing the fuel pressure in the common rail, the common rail type fuel injection device is controlled accurately, and an appropriate amount of fuel is supplied to the common rail at an appropriate timing. Can be supplied to.

  By the way, in the control method for the common rail fuel injection device according to the present invention, as described above, the actual no-pressure feed timing immediately before the fuel pumping is performed while gradually increasing the timing of closing the PCV. Detection is based on fluctuations in fuel pressure. Therefore, in order to correctly learn the response error of the supply pump when there is a factor causing the fluctuation of the fuel pressure in the common rail other than the “change in timing for closing the PCV”, the fuel pressure in the common rail based on the factor is determined. Additional measures such as subtracting fluctuations are required.

  Such additional measures are not desirable because they may complicate the control method for the common rail fuel injection device according to the present invention and reduce the learning accuracy of the response error of the supply pump. That is, in order to improve the learning accuracy of the response error of the supply pump in the control method of the common rail fuel injection device according to the present invention, the factor causing the fluctuation of the fuel pressure in the common rail is “change in timing of closing the PCV. "Is desirable only.

From the above viewpoint, the second aspect of the present invention is:
A control method for a common rail fuel injection device according to the first aspect of the present invention, wherein at least before the fuel pumping step,
An operation state determination step for determining whether or not the operation state of the engine is in a fuel cut state;
A first process interruption step of interrupting execution of the control method of the common rail fuel injection device when the determination result in the operating state determination step is negative;
Is a control method for a common rail fuel injection device.

  In the operation state determination step, as described above, it is determined whether or not the engine operation state is in the fuel cut state. The determination can be made from the operating state of the engine detected based on, for example, measurement signals (detection signals) from various sensors received by the ECU.

  Next, in the first process interruption step, as described above, when the determination result in the operation state determination step is negative, execution of the control method for the common rail fuel injection device is interrupted. The case where the determination result in the operation state determination step is negative indicates a case where the engine operation state is not in the fuel cut state. That is, in this case, since the fuel supply to the engine is not stopped, for example, the fuel pressure in the common rail fluctuates with the fuel injection from the injector into the combustion chamber. As a result, it becomes difficult to accurately detect the variation in the fuel pressure in the common rail due to the “change in timing for closing the PCV”, and the learning accuracy of the response error of the supply pump is lowered.

  However, in this embodiment, as described above, before the fuel pumping step, it is determined whether or not the engine operating state is in the fuel cut state, and the engine operating state is not in the fuel cut state. If determined, the execution of the control method of the common rail fuel injection device is interrupted. As a result, in this embodiment, since learning of the response error of the supply pump is avoided when the engine operating state is not in the fuel cut state, as a result, the learning accuracy of the response error of the supply pump is reduced. improves.

  By the way, as described above, if the injector is operated without taking any special measures while the fuel pressure in the common rail is high, the fuel injection amount increases, for example, an increase in torque generated by the engine is not intended. An effect occurs. Therefore, in the prior art, when the fuel injection state is restored while the fuel pressure in the common rail is rising, the control pulse width of the injector is reduced, and the normal fuel injection amount is maintained, so that the torque is reduced. An unintended increase is avoided. However, the inconvenience that is concerned when the fuel injection is restarted while the fuel pressure in the common rail is rising is not limited to the increase in the fuel injection amount. There are concerns about inconveniences such as an increase in HC and dilution of engine oil.

  Therefore, in order to avoid the above inconvenience, not only the fuel pressure in the common rail is prevented from significantly increasing in the learning of the response error of the supply pump, but also the fuel pressure in the common rail exceeds the target value. If it is high, it is desirable not to learn the response error of the supply pump.

Therefore, the third aspect of the present invention is
A control method for a common rail fuel injection device according to the first aspect of the present invention, wherein at least before the fuel pumping step,
A common rail that determines whether or not a difference between the common rail internal pressure detected by the common rail internal pressure detecting means and a target pressure set corresponding to an operating state of the engine is equal to or greater than a preset maximum allowable pressure difference. An internal pressure determination step;
A second process interruption step of interrupting execution of the control method of the common rail fuel injection device when the determination result in the common rail internal pressure determination step is affirmative;
Is a control method for a common rail fuel injection device.

  In the common rail internal pressure determining step, as described above, the maximum allowable value in which the difference between the common rail internal pressure detected by the common rail internal pressure detecting means and the target pressure set corresponding to the operating state of the engine is set in advance. It is determined whether or not the pressure difference is greater than or equal to. In other words, in the common rail internal pressure determining step, it is determined whether or not the fuel pressure in the common rail is substantially equal to a target pressure set corresponding to the operating state of the engine. As described above, the target pressure of the fuel in the common rail is a pressure set in advance so as to achieve, for example, a desired fuel injection amount and combustion state in accordance with the operating state of the engine. Further, the maximum allowable pressure difference is substantially free from inconveniences such as an increase in fuel injection amount, an increase in combustion noise, an increase in HC in exhaust gas, and dilution of engine oil, as described above. Alternatively, it can be set in advance as a difference between the fuel pressure in the common rail and the target pressure in a state that occurs only to an acceptable degree.

  Next, in the second process interruption step, as described above, when the determination result in the common rail internal pressure determination step is affirmative, execution of the control method for the common rail fuel injection device is interrupted. The case where the determination result in the common rail internal pressure determination step is affirmative refers to the case where the fuel pressure in the common rail is significantly different from the target pressure set corresponding to the operating state of the engine. That is, in this case, since the pressure of the fuel in the common rail is significantly different from the target pressure, for example, as described above, an increase in fuel injection amount, an increase in combustion noise, an increase in HC in exhaust gas, and engine oil Inconvenience such as dilution may occur.

  However, in the present embodiment, as described above, the fuel pressure in the common rail (common rail internal pressure) is substantially equal to the target pressure set corresponding to the operating state of the engine before the fuel pumping step at the latest. It is determined whether the common rail internal pressure is significantly different from the target pressure, and the execution of the control method for the common rail fuel injection device is interrupted. As a result, in this embodiment, the common rail internal pressure, which is significantly different from the target pressure, further fluctuates with the execution of the control method of the common rail fuel injection device, and as a result, fuel injection is resumed thereafter. In this case, for example, the above-described problems such as an increase in fuel injection amount, an increase in combustion noise, an increase in HC in exhaust gas, and dilution of engine oil are avoided.

  As described above, in the second aspect of the present invention, before the fuel pumping step at the latest, it is determined whether or not the engine operating state is in the fuel cut state, and the engine operating state is in the fuel cut state. If it is determined that there is no, the execution of the control method for the common rail fuel injection device is interrupted. In the third aspect of the present invention, the fuel pressure in the common rail (common rail internal pressure) is substantially equal to the target pressure set corresponding to the operating state of the engine before the fuel pumping step at the latest. If it is determined that the common rail internal pressure is significantly different from the target pressure, the execution of the control method for the common rail fuel injection device is interrupted.

  However, as is clear from the above description, when the engine operating state is not in the fuel cut state, and the target pressure that the fuel pressure in the common rail is set corresponding to the engine operating state is greatly different. In different cases, inconveniences occur in each case. Specifically, in the former case, the learning accuracy of the response error of the supply pump is reduced, and in the latter case, when the fuel injection is resumed after learning of the response error of the supply pump, for example, Such inconveniences such as an increase in fuel injection amount, an increase in combustion noise, an increase in HC in exhaust gas, and dilution of engine oil are further exacerbated.

  Therefore, when the engine operating state is not in the fuel cut state, or when the fuel pressure in the common rail is significantly different from the target pressure set corresponding to the engine operating state, the response error of the supply pump It is desirable to avoid learning.

That is, the fourth aspect of the present invention is
A control method for a common rail fuel injection device according to the first aspect of the present invention, wherein at least before the fuel pumping step,
An operation state determination step for determining whether or not the operation state of the engine is in a fuel cut state;
A common rail that determines whether or not a difference between the common rail internal pressure detected by the common rail internal pressure detecting means and a target pressure set corresponding to an operating state of the engine is equal to or greater than a preset maximum allowable pressure difference. An internal pressure determination step;
If the determination result in the operating state determination step is negative, or if the determination result in the common rail internal pressure determination step is affirmative, the execution of the control method for the common rail fuel injection device is interrupted. When,
Is a control method for a common rail fuel injection device.

  Since the operation state determination step and the common rail internal pressure determination step have already been described in detail, description thereof is omitted here. In the third process interruption step, as described above, when the determination result in the operation state determination step is negative or when the determination result in the common rail internal pressure determination step is affirmative, the common rail fuel injection device The execution of the control method is interrupted. In other words, in the third process interruption step, when the engine operating state is not in the fuel cut state, or the fuel pressure in the common rail is significantly different from the target pressure set corresponding to the engine operating state. If they are different, control is performed so as not to learn the response error of the supply pump.

  As a result of the above, after learning the supply pump response error when the learning error of the supply pump response error, which is a concern when the engine is not in the fuel cut state, or when the common rail internal pressure is significantly different from the target pressure, Problems such as an increase in fuel injection amount, an increase in combustion noise, an increase in HC in exhaust gas, and dilution of engine oil, which are feared when fuel injection is resumed, can be avoided.

  Note that an algorithm corresponding to a series of processes in the various embodiments described above is also stored as a program that defines a process that is stored in a storage device such as a ROM or a RAM included in the ECU and executed by the CPU included in the ECU. It may be.

  As mentioned above, although several embodiments of the control method of the common rail type fuel injection device according to the present invention have been described, the scope of the present invention is not limited to these methods, and the common rail type to which these methods are applied. Fuel injectors are also within the scope of the present invention. The details of the common rail fuel injection device are apparent from the description of the control method of the common rail fuel injection device according to each of the embodiments described so far, and therefore will not be described here again. Only the components of the fuel injection device are listed below.

The fifth aspect of the present invention is:
A common rail,
A supply pump for supplying pressurized fuel to the common rail;
A discharge amount control valve provided in the supply pump;
A pump closing timing control means for controlling a pump closing timing which is a timing for closing the discharge amount control valve;
Common rail internal pressure detection means for detecting the common rail internal pressure which is the pressure in the common rail;
Pressure reducing means for reducing the pressure in the common rail by discharging the fuel in the common rail;
Decompression means control means for controlling the operation of the decompression means;
In a common rail fuel injection device comprising:
The pressure reducing means control means prohibits the operation of the pressure reducing means to prohibit the discharge of fuel in the common rail;
The pump closing timing control means sets the pump closing timing to a predetermined initial value that does not cause fuel pumping;
The supply pump and the discharge amount control valve are operated at a set pump closing timing;
When the difference between the common rail internal pressures detected by the pressure detection means before and after the operation of the supply pump and the discharge amount control valve is smaller than a predetermined minimum pressure change amount, the pump closing timing control means The closing timing is set by advancing in a predetermined increment, the operation is returned to the operation of the supply pump and the discharge amount control valve according to the set pump closing timing, and the supply pump and the discharge amount control valve When the difference between the common rail internal pressures detected by the pressure detecting means before and after the operation is larger than a predetermined minimum pressure change amount, the previously set pump closing timing is set as the actual no-pressure feeding timing, and the supply pump Model no-pressure feeding time and actual no-pressure feeding time Obtaining the difference with the period, and correcting the learning value of the pump closing time based on the difference,
It is a common rail type fuel injection device characterized by performing a series of processings including.

Next, the sixth aspect of the present invention includes
A common rail fuel injection device according to the fifth aspect of the present invention,
Before the supply pump and the discharge amount control valve are operated at the set pump closing timing at the latest,
When the engine operating state is not in the fuel cut state, do not execute the series of processes.
Is a common rail fuel injection device.

The seventh aspect of the present invention is
A common rail fuel injection device according to the fifth aspect of the present invention,
Before the supply pump and the discharge amount control valve are operated at the set pump closing timing at the latest,
When the difference between the common rail internal pressure detected by the common rail internal pressure detecting means and the target pressure set corresponding to the operating state of the engine is equal to or larger than a preset maximum allowable pressure difference, the series of processes is performed. Don't do it,
Is a common rail fuel injection device.

Furthermore, the eighth aspect of the present invention provides
A common rail fuel injection device according to the fifth aspect of the present invention,
Before the supply pump and the discharge amount control valve are operated at the set pump closing timing at the latest,
Maximum allowable pressure in which the difference between the common rail internal pressure detected by the common rail internal pressure detecting means and the target pressure set corresponding to the operating state of the engine is preset when the engine operating state is not in the fuel cut state If the difference is greater than or equal to the difference, do not execute the series of processes,
Is a common rail fuel injection device.

  As described above, in the control method for the common rail fuel injection device and the common rail fuel injection device according to the various embodiments of the present invention, the fuel pumping occurs when the discharge amount control valve (PCV) of the supply pump is closed. It is set to a predetermined initial value, and thereafter, the timing for closing the PCV is gradually advanced by a predetermined increment. Then, the difference between the “time to close the PCV” (actual no-pressure feeding time) immediately before the fuel pumping occurs and the no-pressure feeding time (model no-pressure feeding time) for the standard model of the supply pump is obtained. Based on this, the response error of the supply pump is learned. As a result, the response error of the supply pump is learned without significantly increasing the fuel pressure in the common rail, the common rail type fuel injection device is controlled accurately, and an appropriate amount of fuel is supplied to the common rail at an appropriate timing. Can be supplied to.

  Hereinafter, a control method for a common rail fuel injection device and a common rail fuel injection device according to some embodiments of the present invention will be described with reference to the accompanying drawings. However, the following description is for illustrative purposes only, and the scope of the present invention should not be construed as being limited to the following description.

  As described above, in the control method for the common rail type fuel injection device according to the present invention, in the common rail type fuel injection device, the operation of the pressure reducing means is prohibited to discharge the fuel in the common rail, and the supply pump to the common rail The supply pump and PCV are operated while gradually setting the timing to close the discharge amount control valve (PCV) from a predetermined initial value at which fuel pumping does not occur. The pump closing time set last time is set as the actual no-pressure feed timing, and the supply pump is based on the difference between the no-pressure feed timing (model no-feed timing) and the actual no-pressure feed timing for the standard model of the supply pump. By learning the response error, the common rail fuel injection device is controlled accurately and the appropriate amount of fuel is appropriately controlled. It makes it possible to supply to the common rail at the timing.

  Such a series of processes will now be described with reference to FIG. FIG. 1 is a flowchart showing a series of processes executed in the control method for the common rail fuel injection device according to one embodiment of the present invention as described above. A series of processes shown in the flowchart can be executed by an ECU (not shown) as an interrupt process for each predetermined crank angle, for example.

  As shown in FIG. 1, in the present embodiment, the engine operating state is the fuel cut state prior to the start of a series of processes, as in the control method for the common rail fuel injection device according to the fourth aspect described above. And whether or not the common rail internal pressure is substantially equal to a target pressure set corresponding to the operating state of the engine is provided.

  In the control method for the common rail fuel injection device according to the present embodiment, as shown in FIG. 1, first, in step S101, it is determined whether or not the engine operating state is a fuel cut state (operating state determination). Step). When it is determined in step S101 that the engine operating state is not in the fuel cut state (step S101: No), as described above, the learning accuracy of the response error of the supply pump may be reduced. The series of processes indicated by is terminated.

  On the other hand, if it is determined in step S101 that the engine operating state is in the fuel cut state (step S101: Yes), then the fuel pressure in the common rail (common rail internal pressure) and the engine operating state correspond. It is determined whether or not the difference from the set target pressure is greater than or equal to a predetermined maximum allowable pressure difference (substantially equal) (step S102: common rail internal pressure determination step). In this embodiment, the common rail internal pressure determination step is executed after the operation state determination step. However, the execution order of these steps is not necessarily the same as that in the present embodiment.

  When it is determined in step S102 that the difference between the common rail internal pressure and the target pressure is greater than or equal to the maximum allowable pressure difference (step S102: Yes), for example, when the fuel injection is resumed as described above, for example, the fuel injection Since there are concerns about inconveniences such as an increase in torque, an increase in combustion noise, an increase in HC in exhaust gas, and dilution of engine oil due to the increase in the amount, the series of processes shown in this flowchart is completed.

  On the other hand, if it is determined in step S102 that the difference between the common rail internal pressure and the target pressure is less than the maximum allowable pressure difference (step S102: No), then the common rail pressure is discharged by discharging the fuel in the common rail. The operation of the pressure reducing means provided to reduce the fuel consumption is prohibited, and the discharge of fuel in the common rail is prohibited (step S103). As a result, as described above, due to the pressure reducing means operating and the pressure in the common rail fluctuating, the detection accuracy of the responsiveness of the supply pump by the control method of the common rail fuel injection device according to this embodiment is improved. Decrease is prevented in advance.

  From here, the relationship between the set value of the pump closing timing and the pumping amount of fuel will be described in more detail with reference to FIG. FIG. 2 is a graph schematically showing the relationship between the pump closing timing and the fuel pumping amount in the control method for the common rail fuel injection device according to one embodiment of the present invention, as described above. More specifically, the horizontal axis of the graph shown in FIG. 2 represents the pump closing timing, and the vertical axis represents the fuel pumping amount.

  In the graph shown in FIG. 2, the relationship between the pump closing timing and the fuel pumping amount for the standard model supply pump is indicated by a thick solid line. As shown in FIG. 2, in the supply pump of the standard model, fuel pumping does not occur at a timing retarded from the pump closing timing corresponding to the plot indicated by the black circle, and the pump closing corresponding to the plot indicated by the black circle is performed. The fuel is pumped at the timing that is more advanced than the timing. That is, the pump closing time corresponding to the plot indicated by the black circle is the model no-pressure feeding time in this embodiment.

  Next, in the present embodiment, in step S104, the pump closing timing is set to a predetermined initial value at which the fuel is not pumped by the pump closing timing control means (pump closing timing setting step). The initial value of the pump closing time corresponds to a plot represented by the rightmost circle in the graph shown in FIG.

  Next, in step S105, the supply pump and the discharge amount control valve are operated at the set pump closing timing (fuel pressure feeding step). Subsequently, in step S106, pressure detection is performed before and after the fuel pressure feeding step (step S105). It is determined whether or not the difference between the common rail internal pressures detected by the means, that is, the change in the common rail internal pressure in the fuel pumping step (step S105) is equal to or greater than a predetermined minimum pressure change amount (ΔPmin) (pressure change). Judgment step).

  As described above, in the pump closing timing setting step (step S104), the pump closing timing is set to a predetermined initial value at which fuel pumping does not occur. Therefore, in the graph shown in FIG. As can be seen from the plots represented by the corresponding circles, even if the fuel pumping step (step S105) is performed at the pump closing timing set to the initial value, fuel pumping does not occur, and as a result, At least in the first pressure change determination step (step S106), a change in the common rail internal pressure equal to or greater than ΔPmin is not detected (step S106: No).

  As described above, when a change in the common rail internal pressure exceeding the minimum pressure change amount (ΔPmin) is not detected (step S106: No), in step S107, the pump closing timing is advanced by a predetermined increment (pump closing). Time resetting step). This pump closing time resetting step (step S107) corresponds to setting the pump closing time corresponding to the plot on the left side of the plot corresponding to the initial value in the graph shown in FIG. As shown in the graph of FIG. 2, fuel pumping does not occur even at the pump closing time corresponding to the second plot, and the pump closing time resetting step (step S107) is executed again.

  In FIG. 2, fuel pumping does not occur at the pump closing time corresponding to the third plot, but fuel pumping occurs at the pump closing time corresponding to the fourth plot. As described above, the fuel is pumped in the fuel pumping step several times (step S105), and the change in the common rail pressure more than ΔPmin is detected in the pressure change determination step (step S106) at that time (step S106). : Yes).

  When the determination result in the pressure change determination step (step S106) is affirmative as described above (step S106: Yes), in step S108, the pump closing time (Rt) set at that time (4 in FIG. 2). The pump closing time (Rt) (corresponding to the third plot in FIG. 2) set last time is set as the actual non-feeding time (Rt_min), not the first plot. Then, the difference (ΔT) between the model no-pressure feed timing (Mt_min), which is the no-pressure feed timing for the standard model of the supply pump, and the actual no-pressure feed timing (Rt_min) is obtained. This difference (ΔT) corresponds to the difference between the third plot in FIG. 2 (circles drawn with bold lines) and the plot corresponding to the non-feeding time in the standard model (black circles). Further, in step S109, the learning value of the pump closing timing is corrected based on the difference (ΔT). That is, steps S108 and S109 constitute a pump closing timing learning step.

  As described above, in this embodiment, prior to learning the response error of the supply pump, when the engine operating state is not in the fuel cut state (step S101: No), or the fuel pressure in the common rail is the engine operating state. When the target pressure set corresponding to the state is significantly different (step S102: Yes), the supply pump response error is not learned. As a result, the learning accuracy of the supply pump response error decreases, or when fuel injection is resumed after learning of the supply pump response error, the fuel injection amount increases, the combustion noise increases, and the HC in the exhaust gas increases. It is possible to avoid further inconveniences such as increase and dilution of engine oil. However, this feature of the present embodiment is not an essential requirement in the control method for the common rail fuel injection device according to the present invention.

  Further, in this embodiment, in the common rail fuel injection device, the operation of the pressure reducing means is prohibited to discharge the fuel in the common rail (step S103), and the supply pump discharge amount control valve (PCV) to the common rail The supply pump and the PCV are operated while the timing of closing is set by gradually advancing from a predetermined initial value at which fuel pumping does not occur (steps S104 to S107), and the common rail internal pressure is significantly increased by these operations. (Step S106: Yes), the previously set pump closing time is set as the actual no-pressure feeding time (Rt_min), the no-pressure feeding time (model no-pressure feeding time: Mt_min) and the actual no-pressure feeding time for the standard model of the supply pump. Based on the difference (ΔT) with respect to (step S108), the response error of the supply pump By learning (step S109), the common rail fuel injection apparatus is accurately controlled, can be supplied to the common rail an appropriate amount of fuel at appropriate timing.

  In the foregoing, for the purpose of illustrating the present invention, several embodiments having specific configurations and combinations of execution procedures have been described, but the scope of the present invention is limited to these exemplary embodiments. Instead, modifications can be appropriately made within the scope of the matters described in the claims and the specification.

Claims (8)

A common rail,
A supply pump for supplying pressurized fuel to the common rail;
A discharge amount control valve provided in the supply pump;
A pump closing timing control means for controlling a pump closing timing which is a timing for closing the discharge amount control valve;
Common rail internal pressure detection means for detecting the common rail internal pressure which is the pressure in the common rail;
Pressure reducing means for reducing the pressure in the common rail by discharging the fuel in the common rail;
Decompression means control means for controlling the operation of the decompression means;
In a common rail fuel injection device comprising:
A pressure reducing means operation prohibiting step for prohibiting the operation of the pressure reducing means and prohibiting the discharge of fuel in the common rail;
A pump closing timing setting step for setting the pump closing timing to a predetermined initial value at which the pumping of fuel does not occur, by the pump closing timing control means;
A fuel pumping step of operating the supply pump and the discharge amount control valve at a set pump closing time;
A pressure change determination step for determining whether or not the difference between the common rail internal pressures detected by the pressure detection means before and after the fuel pumping step is greater than or equal to a predetermined minimum pressure change amount; and
If the determination result in the pressure change determination step is negative, the pump closing timing is set by advancing and setting the pump closing timing by a predetermined increment, and the processing flow is returned to the fuel pumping step. When,
If the determination result in the pressure change determination step is affirmative, the previously set pump closing timing is set as the actual no-pressure feeding timing, and the model no-pressure feeding timing, which is the no-pressure feeding timing for the standard model of the supply pump, A pump closing timing learning step for obtaining a difference with the pumping timing and correcting a learning value of the pump closing timing based on the difference;
A control method for a common rail fuel injection device, comprising: It is a control method of the common rail type fuel injection device according to claim 1, Comprising: Before the fuel pumping step at the latest,
An operation state determination step for determining whether or not the operation state of the engine is in a fuel cut state;
A first process interruption step of interrupting execution of the control method of the common rail fuel injection device when the determination result in the operating state determination step is negative;
A control method for a common rail fuel injection device, further comprising: It is a control method of the common rail type fuel injection device according to claim 1, Comprising: Before the fuel pumping step at the latest,
A common rail that determines whether or not a difference between the common rail internal pressure detected by the common rail internal pressure detecting means and a target pressure set corresponding to an operating state of the engine is equal to or greater than a preset maximum allowable pressure difference. An internal pressure determination step;
A second process interruption step of interrupting execution of the control method of the common rail fuel injection device when the determination result in the common rail internal pressure determination step is affirmative;
A control method for a common rail fuel injection device, further comprising: It is a control method of the common rail type fuel injection device according to claim 1, Comprising: Before the fuel pumping step at the latest,
An operation state determination step for determining whether or not the operation state of the engine is in a fuel cut state;
A common rail that determines whether or not a difference between the common rail internal pressure detected by the common rail internal pressure detecting means and a target pressure set corresponding to an operating state of the engine is equal to or greater than a preset maximum allowable pressure difference. An internal pressure determination step;
If the determination result in the operating state determination step is negative, or if the determination result in the common rail internal pressure determination step is affirmative, the execution of the control method for the common rail fuel injection device is interrupted. When,
A control method for a common rail fuel injection device, further comprising: A common rail,
A supply pump for supplying pressurized fuel to the common rail;
A discharge amount control valve provided in the supply pump;
A pump closing timing control means for controlling a pump closing timing which is a timing for closing the discharge amount control valve;
Common rail internal pressure detection means for detecting the common rail internal pressure which is the pressure in the common rail;
Pressure reducing means for reducing the pressure in the common rail by discharging the fuel in the common rail;
Decompression means control means for controlling the operation of the decompression means;
In a common rail fuel injection device comprising:
The pressure reducing means control means prohibits the operation of the pressure reducing means to prohibit the discharge of fuel in the common rail;
The pump closing timing control means sets the pump closing timing to a predetermined initial value that does not cause fuel pumping;
The supply pump and the discharge amount control valve are operated at a set pump closing timing;
When the difference between the common rail internal pressures detected by the pressure detection means before and after the operation of the supply pump and the discharge amount control valve is smaller than a predetermined minimum pressure change amount, the pump closing timing control means The closing timing is set by advancing in a predetermined increment, the operation is returned to the operation of the supply pump and the discharge amount control valve according to the set pump closing timing, and the supply pump and the discharge amount control valve When the difference between the common rail internal pressures detected by the pressure detecting means before and after the operation is larger than a predetermined minimum pressure change amount, the previously set pump closing timing is set as the actual no-pressure feeding timing, and the supply pump Model no-pressure feeding time and actual no-pressure feeding time Obtaining the difference with the period, and correcting the learning value of the pump closing time based on the difference,
A common rail fuel injection device characterized by performing a series of processes including: The common rail fuel injection device according to claim 5,
Before the supply pump and the discharge amount control valve are operated at the set pump closing timing at the latest,
When the engine operating state is not in the fuel cut state, do not execute the series of processes.
A common rail fuel injection device characterized by further features. The common rail fuel injection device according to claim 5,
Before the supply pump and the discharge amount control valve are operated at the set pump closing timing at the latest,
When the difference between the common rail internal pressure detected by the common rail internal pressure detecting means and the target pressure set corresponding to the operating state of the engine is equal to or larger than a preset maximum allowable pressure difference, the series of processes is performed. Don't do it,
A common rail fuel injection device characterized by further features. The common rail fuel injection device according to claim 5,
Before the supply pump and the discharge amount control valve are operated at the set pump closing timing at the latest,
Maximum allowable pressure in which the difference between the common rail internal pressure detected by the common rail internal pressure detecting means and the target pressure set corresponding to the operating state of the engine is preset when the engine operating state is not in the fuel cut state If the difference is greater than or equal to the difference, do not execute the series of processes,
A common rail fuel injection device characterized by further features.

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