JP2008088897A - Injection quantity control device and injection quantity control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection quantity control device and an injection quantity control method in which the fuel injection quantity is stabilized. <P>SOLUTION: After a driving pulse 61 is inputted to a fuel injection valve for injecting a high pressure fuel introduced from an accumulating chamber of a common rail and the high pressure fuel is injected, a dummy pulse 62 is inputted and a solenoid valve is opened within the range in which a valve element does not open. Thereby, new pressure pulsation is generated in the accumulating chamber for canceling the pressure pulsation generated in the accumulating chamber by fuel injection of the fuel injection valve. The fuel injection quantity is thereby stabilized. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention particularly relates to an injection amount control device and an injection amount control method for controlling a fuel injection valve that injects high-pressure fuel accumulated in a pressure accumulation chamber of a common rail.

2. Description of the Related Art Conventionally, an injection amount control device that controls a fuel injection valve that injects high-pressure fuel accumulated in a common rail pressure accumulation chamber is known (see, for example, Patent Documents 1 and 2).
Incidentally, the injection amount control device generally controls the fuel injection amount based on the fuel pressure in the pressure accumulating chamber. However, the fuel pressure in the pressure accumulating chamber has a problem that pressure pulsation occurs due to fuel injection into other cylinders or previous fuel injection into the own cylinder, and there is a problem that the fuel injection amount fluctuates due to the pressure pulsation.

  In general, the fuel injection valve also has a problem that the fuel injection amount varies among individuals. As a method of reducing the variation in the fuel injection amount among individuals, a method of adjusting the fuel injection period according to the individual may be considered, but this method has the problem that the injection timing changes and the engine performance is affected. There is.

Japanese Patent Laid-Open No. 5-125985 JP 2004-108286 A

  The present invention has been created to solve the above-described problems, and an object thereof is to provide an injection amount control device and an injection amount control method in which the fuel injection amount is stable.

  According to the first to seventh aspects of the present invention, since the new pressure pulsation that cancels the pressure pulsation generated in the pressure accumulating chamber of the common rail by the fuel injection by the fuel injection valve is generated in the pressure accumulating chamber, the pressure pulsation in the pressure accumulating chamber can be suppressed. . Therefore, the fuel injection amount is stabilized.

  According to the invention described in claim 2, the new pressure pulsation is generated by using the fuel injection valve for injecting the high-pressure fuel. For example, a new pressure pulsation can be generated in the pressure accumulating chamber by providing a pressure reducing valve in the pressure accumulating chamber, but in that case, it is necessary to provide a pressure reducing valve separately from the fuel injection valve, and the number of parts increases. When the fuel injection valve is used, a new pressure pulsation can be generated without increasing the number of parts.

  According to the invention described in claim 4, a new pressure pulsation is generated only when the magnitude of the pressure pulsation is not less than a predetermined magnitude. When the magnitude of the pressure pulsation is less than a predetermined magnitude, the variation in the fuel injection amount is small, so that it is not always necessary to generate a new pressure pulsation for canceling out the pressure pulsation. Nevertheless, when a new pressure pulsation is generated, it becomes a factor that causes a large pressure pulsation in the pressure accumulating chamber. Therefore, when the magnitude of the pressure pulsation is less than a predetermined magnitude, it is possible to prevent the pressure pulsation from being generated unnecessarily by not generating a new pressure pulsation.

  According to the fifth aspect of the present invention, since the new pressure pulsation is determined according to the pressure pulsation in the pressure accumulating chamber, the new pressure pulsation having an appropriate magnitude according to the pressure pulsation Can be generated.

  According to the invention described in claim 6, since a new pressure pulsation is generated a plurality of times, if the pressure pulsation is large and the pressure pulsation cannot be sufficiently canceled by only one occurrence of the pressure pulsation, The pressure pulsation can be canceled more reliably by adding a new pressure pulsation to the new pressure pulsation.

  According to the invention described in claims 8 to 15, pressure pulsation is generated in the pressure accumulation chamber of the common rail before the high pressure fuel is injected. At this time, the fuel pressure at the time of fuel injection by the fuel injection valve can be adjusted by adjusting the phase of pressure pulsation. Therefore, the fuel injection amount is stabilized.

  According to the ninth aspect of the present invention, the pressure pulsation for adjusting the fuel pressure at the time of fuel injection is generated using the fuel injection valve for injecting high-pressure fuel. When the fuel injection valve is used, pressure pulsation for adjusting the fuel pressure can be generated without increasing the number of parts.

  According to the eleventh aspect of the present invention, the pressure pulsation generating means generates the pressure pulsation only when the variation in the injection amount of the fuel injection valve is outside the allowable range. When the variation in the injection amount is within the allowable range, it is not always necessary to generate a pressure pulsation for adjusting the fuel pressure in the pressure accumulating chamber. Nevertheless, if pressure pulsation is generated, it becomes a factor that fluctuates the fuel pressure in the pressure accumulating chamber. Therefore, when the variation in the injection amount is within the allowable range, it is possible to prevent the fuel pressure from fluctuating unnecessarily by not generating pressure pulsation.

  According to the twelfth aspect of the present invention, since the phase of the pressure pulsation is determined according to the injection amount characteristic specific to the fuel injection valve, the variation in the fuel injection amount among individuals can be corrected.

  According to the invention described in claim 13, the magnitude of the pressure pulsation is determined according to the fuel pressure in the pressure accumulating chamber. For example, even with the same fuel injection valve, if the fuel pressure in the pressure accumulating chamber is high, a large pressure pulsation is required to reduce the fuel pressure during fuel injection to the target fuel pressure. By determining the magnitude of the pressure pulsation according to the fuel pressure in the pressure accumulating chamber, it is possible to generate a pressure pulsation of an appropriate magnitude that makes the fuel pressure during fuel injection the target fuel pressure.

  According to the invention described in claim 14, since the pressure pulsation is generated a plurality of times, if the variation in the injection amount of the fuel injection valve is large and the injection amount cannot be sufficiently corrected by only one occurrence of the pressure pulsation, it is generated last time. By adding the generated pressure pulsation to the pressure pulsation, the injection amount can be corrected to a predetermined target value.

  Hereinafter, embodiments of the present invention will be described based on a plurality of examples. In each embodiment, the component with the same code | symbol respond | corresponds with the component of the other embodiment to which the code | symbol was attached | subjected. In the following description, “electronic control unit” is abbreviated as “ECU”.

(First embodiment)
The first embodiment is an example in which a pressure pulsation generated in a pressure accumulation chamber of a common rail due to fuel injection by a fuel injection valve is canceled by a new pressure pulsation.
FIG. 2 is a schematic view showing a common rail fuel injection system 10 of a diesel engine to which the injection amount control device according to the first embodiment of the present invention is applied.
Each cylinder of a diesel engine (not shown) is provided with a fuel injection valve 11, and high pressure fuel is supplied to the fuel injection valve 11 from a pressure accumulation chamber of a common rail 13 via a supply line 12. Therefore, fuel having a pressure equal to the pressure of the fuel in the accumulator (accumulation chamber pressure) is injected from the fuel injection valve 11 into the combustion chamber of each cylinder.

  The fuel in the fuel tank 14 is pressurized and fed to the common rail 13 by a high-pressure pump 15. The fed fuel is stored in a pressure accumulation state in a pressure accumulation chamber. A part of the fuel stored in the pressure accumulating chamber is also used as hydraulic oil for the fuel injection valve 11. The fuel used as the working oil supplied from the pressure accumulating chamber to the fuel injection valve 11 is returned to the fuel tank 14 via the low-pressure reflux path 16.

  A pressure sensor 17 is provided on the common rail 13. The pressure accumulation chamber pressure is detected by the pressure sensor 17 and output to the ECU 18. Here, the ECU corresponds to the “injection amount control device” recited in the claims. The ECU 18 controls the metering valve 19 based on the pressure accumulation chamber pressure detected by the pressure sensor 17 and adjusts the flow rate of the fuel supplied to the pressure accumulation chamber. The ECU 18 controls the accumulator pressure so as to be appropriate in accordance with the operating state of the engine determined based on signals input from other various sensors.

Next, an example of the fuel injection valve 11 will be described.
FIG. 3 is a cross-sectional view of the fuel injection valve 11.
The nozzle portion 31 is provided on the opposite side of the housing 32 from the electromagnetic drive portion 33. The nozzle portion 31 has a nozzle body 34, and an injection hole 35 is formed in the vicinity of the tip portion of the nozzle body 34. A valve needle 36 as a valve body is accommodated on the inner peripheral side of the nozzle body 34 so as to be reciprocally movable in the axial direction. A contact portion 37 is formed on the valve needle 36 and can contact a valve seat portion 38 formed on the inner peripheral side of the nozzle body 34. When the contact portion 37 is seated on the valve seat portion 38 or the valve seat portion 38 is separated from the contact portion 37, the fuel injection from the injection hole 35 is interrupted.

A piston 39 that contacts the valve needle 36 is accommodated in the housing 32. A control chamber 40 is formed in the housing 32 on the side opposite to the valve needle 36 of the piston 39. The control chamber 40 stores high-pressure fuel supplied from the fuel inlet 41.
The spring 42 is accommodated in the housing 32 in a compressed state. The end of the spring 42 on the electromagnetic drive 33 side is in contact with a stepped portion 43 formed in the housing 32, and the other end presses the piston 39 toward the injection hole 35.

The piston 39 is urged downward in FIG. 2 by the high pressure fuel stored in the control chamber 40 and the spring 42. By urging the piston 39, the valve needle 36 is urged in the injection hole closing direction. That is, the contact portion 37 of the valve needle 36 is biased in the direction in which the valve needle 36 is seated on the valve seat portion 38 of the nozzle body 34.
The fuel inlet 41 is supplied with high-pressure fuel stored in a pressure accumulation state on the common rail 13 (not shown). A part of the high-pressure fuel supplied from the common rail 13 is supplied to the control chamber 40 via the fuel passage 44, and the other part is supplied to the nozzle portion 31.

The fuel passage 45 connects the fuel passage 44 and the control chamber 40.
The fuel passage 46 connects the control chamber 40 and the fuel passage 47. When a solenoid valve (not shown) included in the electromagnetic drive unit 33 is opened, the fuel in the control chamber 40 is returned to the fuel tank 14 via the fuel passage 46 and the connection passage 47.
The fuel passage 48 connects the fuel passage 44 and the fuel reservoir chamber 49.

  The electromagnetic drive unit 33 is installed on the opposite side of the housing 32 from the nozzle unit 31. The electromagnetic drive unit 33 has a solenoid valve (not shown) that discharges the fuel stored in the control chamber 40. When the solenoid valve is opened and the fuel in the control chamber 40 is discharged, the pressure in the control chamber 40 decreases, and the force that urges the valve needle 36 in the nozzle hole closing direction decreases. Then, the valve needle 36 is biased in the nozzle hole opening direction by the pressure in the fuel reservoir chamber 49 rather than the force that biases the valve needle 36 in the nozzle hole closing direction by the fuel pressure in the control chamber 40 and the spring 42. As the force increases, the valve needle 36 lifts upward in FIG. When the valve needle 36 is lifted, the contact portion 37 is separated from the valve seat portion 38, and fuel is injected from the injection hole 35.

  On the other hand, when the solenoid valve is closed and the fuel discharge from the control chamber 40 is stopped, the pressure in the control chamber 40 increases, and the force for urging the valve needle 36 in the nozzle hole closing direction increases. Therefore, the valve needle 36 moves downward in FIG. 2 and the contact portion 37 is seated on the valve seat portion 38. When the contact portion 37 is seated on the valve seat portion 38, fuel injection from the injection hole 35 is stopped.

Next, an outline of an operation for canceling the pressure pulsation generated in the pressure accumulation chamber of the common rail 13 will be described.
FIG. 1A is a schematic diagram showing pressure pulsation generated in the pressure accumulation chamber of the common rail 13. In the fuel injection described above, when the solenoid valve is opened and the fuel pressure in the control chamber 40 is released, pressure pulsation occurs in the pressure accumulating chamber. Specifically, when the drive pulse 61 is turned ON at the time point P, the fuel pressure is released from the control chamber 40, so that the high pressure fuel in the pressure accumulation chamber is introduced into the control chamber 40 and the pressure accumulation chamber pressure decreases. When fuel injection is interrupted at time Q, the pressure in the accumulator chamber starts to increase due to the high-pressure fuel supplied from the high-pressure pump 15. At this time, the fuel pressure is excessively increased in the pressure accumulating chamber due to the high-pressure fuel introduced from the high-pressure pump 15. When the pressure in the accumulator increases to a certain extent, the limit is reached, and the excessively increased fuel pressure starts to flow backward to the high-pressure pump 15 side. Time S in the figure indicates the time when the pressure in the accumulator chamber has increased most. By repeating this, pressure pulsation is generated in the pressure accumulating chamber. The cycle of the generated pressure pulsation correlates with the length of the pipe connecting the high pressure pump 15 and the pressure accumulating chamber.

FIG. 1B is a schematic diagram showing a change in pressure pulsation in the pressure accumulating chamber when a new pressure pulsation is generated. After outputting the drive pulse 61, the ECU 18 generates a new pressure pulsation by outputting a dummy pulse 62 as shown.
FIG. 6D shows the relationship between the amount of change in the pressure accumulation chamber pressure due to the occurrence of a new pressure pulsation and the elapsed time after the dummy pulse 62 is turned off (hereinafter referred to as “elapsed time after driving”). It is a graph to show. In other words, FIG. 6D is a graph showing a new pressure pulsation waveform. The waveform of the new pressure pulsation starts to decrease when the dummy pulse 62 is turned off, and the negative change amount becomes maximum at the time point W at which the quarter period has elapsed. The ECU 18 determines the output timing of the dummy pulse 62 so that the time point W at which the negative change amount becomes maximum coincides with the time point S shown in FIG. When the dummy pulse 62 is output to generate a new pressure pulsation in the pressure accumulating chamber, the pressure pulsation generated in the pressure accumulating chamber due to fuel injection is canceled by the new pressure pulsation. Thereby, the pressure pulsation in the pressure accumulating chamber is suppressed as shown in FIG.

Next, details of the operation for canceling the pressure pulsation will be described.
FIG. 4 is a flowchart showing a flow of processing for canceling pressure pulsation.
In S105, the ECU 18 detects the operating state of the engine based on the engine speed, the accelerator opening, and the like.

  In S110, the ECU 18 calculates the fuel injection amount and the fuel injection timing based on the operating state. Since the calculation of the fuel injection amount and the fuel injection timing based on the operating state is known, a detailed description is omitted. However, the fuel injection timing is not fixed to the one calculated here, but is finally determined by adjusting the “injection start delay time” described later.

In S <b> 115, the ECU 18 executes “injection valve drive control” to inject fuel from the fuel injection valve 11. Details of the “injection valve drive control” will be described later.
In S120, the ECU 18 determines whether the next injection control is started. For example, depending on the operating state, after injection may be performed after the main injection, the next injection control refers to this after injection. When after-injection is performed, there is no time during which the dummy pulse 62 is being output, so the process is terminated without outputting the dummy pulse 62.

In S125, the ECU 18 detects the pressure accumulation chamber pressure.
In S130, the ECU 18 determines the magnitude of the pressure pulsation based on the pressure accumulation chamber pressure. In FIG. 1B, the pressure V indicates the pressure when the fuel pressure becomes the lowest immediately after fuel injection. The ECU 18 determines that “pressure pulsation is large” if the pressure V is equal to or less than a predetermined value. If it is determined that the pressure pulsation is large, the ECU 18 proceeds to S135, and otherwise the process is terminated. When the pressure pulsation is small, the fluctuation of the fuel injection amount is small, and therefore it is not always necessary to generate a new pressure pulsation for canceling out the pressure pulsation. Nevertheless, when a new pressure pulsation is generated, it becomes a factor that causes a large pressure pulsation in the pressure accumulating chamber. Therefore, when the magnitude of the pressure pulsation is less than a predetermined magnitude, it is possible to prevent the pressure pulsation from being generated unnecessarily by not generating a new pressure pulsation.

Here, the magnitude of the pressure pulsation is determined based on the pressure accumulation chamber pressure, but may be determined based on the fuel injection amount calculated in S110. This is because the pressure pulsation increases as the fuel injection amount increases.
In S135, the ECU 18 generates “new injection pulsation” in the pressure accumulation chamber of the common rail 13 by executing “non-injection injection valve drive control” that opens the electromagnetic valve within a range in which the valve element does not open. Details of the “non-injection injection valve drive control” will be described later.

  After the new pressure pulsation is generated by the “non-injection injection valve drive control”, the ECU 18 returns to S120 and repeats the process until the pressure pulsation becomes small. That is, the ECU 18 feedback-controls the electromagnetic valve according to the pressure accumulation chamber pressure after generating a new pressure pulsation. As a result, even if the pressure pulsation cannot be sufficiently canceled only by the generation of one pressure pulsation, it can be surely canceled by repeatedly generating a new pressure pulsation.

Next, “injection valve drive control” will be described.
FIG. 5 is a flowchart showing a flow of processing of “injection valve drive control”.
In S205, the ECU 18 detects the pressure accumulation chamber pressure.
In S210, the ECU 18 opens the solenoid valve based on the fuel injection amount and fuel injection timing calculated in S110 and the pressure accumulation chamber pressure detected in S205 (hereinafter referred to as “injection valve drive period”), and The final fuel injection timing (hereinafter referred to as “injection valve drive timing”) is calculated. This will be specifically described below.

FIG. 6A is a graph for calculating the injection valve drive period based on the fuel injection amount and the fuel pressure. The ECU 18 determines the injection valve drive period from the graph shown in FIG. 6A based on the fuel injection amount and the fuel pressure.
FIG. 6B is a graph for calculating the injection start delay time based on the fuel pressure. The time required from when the solenoid valve is opened to when the fuel is actually injected varies depending on the pressure in the pressure accumulation chamber. For example, when the pressure in the pressure accumulation chamber is low, the time until the fuel is actually injected becomes long. Conversely, when the pressure in the pressure accumulation chamber is high, the time until the fuel is actually injected becomes short. Therefore, the ECU 18 determines the injection valve drive timing in anticipation of this delay. Specifically, the ECU 18 determines the injection start delay time from the graph shown in FIG. 6B based on the fuel pressure. Next, the ECU 18 determines the final injection valve drive timing as a time point that is earlier than the fuel injection timing calculated in S110 by the injection start delay time.

  In S215, the solenoid valve is opened during the calculated injection valve drive period at the calculated injection valve drive timing. Thereby, fuel is injected.

Next, “non-injection injection valve drive control” will be described.
FIG. 7 is a flowchart showing a process flow of “non-injection injection valve drive control”.
In S305, the ECU 18 detects the pressure accumulation chamber pressure. Since the pressure accumulation chamber pressure has already been detected in S125, the pressure accumulation chamber pressure detected in S125 may be used.
In S310, the ECU 18 calculates a non-injection injection valve drive period and a non-injection injection valve drive timing based on the pressure accumulation chamber pressure detected in S305.

  FIG. 6C is a graph for calculating the non-injection injector driving period based on the fuel pressure. The ECU 18 determines the non-injection injection valve drive period t1 from the graph shown in FIG. 6C based on the fuel pressure. Thus, by determining the non-injection injection valve driving period based on the pressure accumulation chamber pressure, it is possible to generate a pressure pulsation having an appropriate magnitude according to the pressure accumulation chamber pressure.

  FIG. 6D is a graph showing the relationship between the amount of change in the pressure accumulation chamber pressure due to the occurrence of a new pressure pulsation and the elapsed time after driving, as described above. The ECU 18 acquires an elapsed time t2 from when the dummy pulse 62 is turned OFF until the time point W at which the negative change amount of the pressure accumulation chamber pressure reaches a maximum is reached from the graph. Next, the ECU 18 specifies a time point S shown in FIG. The period of the generated pressure pulsation correlates with the length of the pipe connecting the high-pressure pump 15 and the pressure accumulating chamber, and the time S can be uniquely identified from the length of the pipe. Next, the ECU 18 determines a time point X (see FIG. 1 (B)) that is (t1 + t2) time back from the time point S as a non-injection injection valve drive timing at which the dummy pulse 62 is turned on.

  In S315, the ECU 18 outputs a dummy pulse 62 so that the solenoid valve is opened for a time t1 from the time point X. As a result, a new pressure pulsation is generated in the pressure accumulating chamber. With this new pressure pulsation, the pressure pulsation generated in the pressure accumulation chamber by the fuel injection in S115 is canceled, and the pressure pulsation in the pressure accumulation chamber is suppressed as shown in FIG.

  According to the injection amount control apparatus according to the first embodiment of the present invention described above, the pressure pulsation generated in the pressure accumulation chamber of the common rail 13 by the fuel injection by the fuel injection valve 11 is canceled by generating a new pressure pulsation. The pressure pulsation in the pressure accumulating chamber can be suppressed. Therefore, the fuel injection amount is stabilized.

(Second Embodiment)
The second embodiment is an example of adjusting the fuel pressure during fuel injection by generating pressure pulsation in the pressure accumulation chamber of the common rail before fuel injection.
First, the outline of the operation for adjusting the fuel pressure during fuel injection will be described.
FIG. 8A is a schematic diagram showing variations in fuel injection amounts caused by individual differences in fuel injection valves. Here, a fuel injection valve with a fuel injection amount greater than the design value (large injection amount), a fuel injection valve that is substantially close to the design value (medium injection amount), and a fuel injection valve with a fuel injection amount less than the design value (small injection amount) 3 One example will be described. Further, here, in order to facilitate understanding, the description will be made on the assumption that the pressure pulsation generated in the accumulator chamber by the fuel injection is the same in any fuel injection valve.

FIGS. 8B and 8C are schematic diagrams showing changes in the fuel injection amount when pressure pulsation is generated before fuel injection, and FIG. 8B shows fuel injection with a small injection amount. FIG. 8C shows the change in the fuel injection amount of the large injection amount.
As shown in FIGS. 8B and 8C, the ECU 18 outputs a dummy pulse 63 before outputting the drive pulse 61 to the electromagnetic valve. The waveform of the pressure pulsation generated by the dummy pulse 63 is the same as the waveform shown in FIG. The ECU 18 changes the timing for outputting the dummy pulse 63 between the small injection amount and the large injection amount. As a result of changing the timing, there is a difference in the phase of pressure pulsation generated in the accumulator chamber between the small injection quantity and the large injection quantity, and as a result, the pressure in the accumulator chamber during fuel injection is reduced between the small injection quantity and the large injection quantity. There is a difference.

  Specifically, in the case of small injection quantity products, it is necessary to increase the fuel pressure so that more fuel is injected, so in the case of small injection quantity products, the phase is adjusted so that the fuel pressure during fuel injection is high. Pressure pulsation is generated. As a result, as shown in FIG. 8B, the fuel pressure is corrected to be higher than when only normal pressure pulsation generated by fuel injection is performed, and more fuel is injected.

  On the other hand, in the case of a large injection quantity, it is necessary to lower the fuel pressure so as to inject less fuel. Therefore, in the case of a large injection quantity, the pressure is adjusted by adjusting the phase so that the fuel pressure during fuel injection is low. Pulsation is generated. As a result, as shown in FIG. 8C, the fuel pressure is corrected to be lower than that in the case of only normal pressure pulsation, and less fuel is injected.

Next, the detail of the operation | movement which adjusts the fuel pressure at the time of fuel injection is demonstrated.
FIG. 9 is a flowchart showing an operation flow for adjusting the fuel pressure during fuel injection.
In S405, the ECU 18 detects the operating state of the engine based on the engine speed, the accelerator opening, and the like.

In S410, the ECU 18 calculates the fuel injection amount and the fuel injection timing based on the operating state. Since the calculation of the fuel injection amount and the fuel injection timing based on the operating state is known, a detailed description is omitted.
In S415, the ECU 18 reads out the injection amount variation specific to the fuel injection valve 11 from the ROM provided in the ECU 18.

In S420, the ECU 18 calculates a pressure change amount for correcting the injection amount variation inherent in the fuel injection valve 11. Specifically, the ECU 18 calculates how much the pressure should be corrected in order to obtain an injection amount equivalent to the intermediate injection amount based on the injection amount variation inherent in the fuel injection valve 11.
In S425, the ECU 18 detects the pressure accumulation chamber pressure.

  In S430, the ECU 18 determines the degree of variation in the injection amount of the fuel injection valve 11. When the variation in the injection amount is within the allowable range, the variation in the fuel injection amount is small, and therefore it is not always necessary to generate pressure pulsation for adjusting the fuel pressure during fuel injection. Nevertheless, if pressure pulsation is generated, it becomes a factor that fluctuates the fuel pressure. Therefore, it is possible to prevent the fuel pressure from being changed unnecessarily by not causing pressure pulsation when the injection amount variation is within the allowable range.

In S435, the ECU 18 executes “non-injection injection valve drive control” to generate a new pressure pulsation.
In this “non-injection injection valve drive control”, the calculation method of the non-injection injection valve drive period t1 is the same as in the first embodiment, but the calculation method of the non-injection injection valve drive timing t2 is the first implementation. It is different from the form.
The non-injection injection valve drive period t1 is determined according to the pressure accumulation chamber pressure as in the case of the first embodiment. That is, if the pressure accumulation chamber pressure is high, the valve opening period is lengthened. For example, even with the same fuel injection valve, if the fuel pressure in the pressure accumulating chamber is high, a large pressure pulsation is required to reduce the fuel pressure during fuel injection to the target fuel pressure. The magnitude of the generated pressure pulsation correlates with the valve opening period of the solenoid valve. A pressure pulsation of an appropriate magnitude can be generated.

  On the other hand, the calculation method for the non-injection injection valve drive timing t2 is different from that of the first embodiment. In the case of a small injection amount, it is necessary to increase the fuel pressure so as to inject more fuel. For this reason, the ECU 18 includes, for example, the time M shown in FIG. 6D in the fuel injection section Y shown in FIG. The injection timing is determined as follows. For example, as shown in FIG. 8B, the ECU 18 determines a time point Z that is (t1 + t2 ') hours later from the center point of the fuel injection section Y as a non-injection injection valve drive timing for turning on the dummy pulse 63.

  Here, the case where the injection timing is determined so that the time M is included in the fuel injection section Y has been described as an example, but this is an example, and the time M is shifted back and forth as shown in FIG. The injection timing may be determined so that the time M ′ and the time M ″ are included in the fuel injection section Y. Which time point is included in the fuel injection section Y is appropriately determined according to the pressure accumulation chamber pressure and the injection amount variation.

  On the other hand, in the case of a large injection quantity, it is necessary to lower the fuel pressure so as to inject less fuel. Therefore, the ECU 18 sets the injection timing so that the time point W shown in FIG. decide. In this case as well, which time point is included in the fuel injection section Y is appropriately determined according to the pressure accumulation chamber pressure and the injection amount variation.

In this way, the ECU 18 determines the valve opening timing of the electromagnetic valve according to the injection amount characteristic unique to the fuel injection valve 11. Thereby, the phase of the pressure pulsation is adjusted, and the fuel pressure at the time of fuel injection is adjusted, so that variation in the fuel injection amount among individuals can be reduced.
In S440, the ECU 18 determines whether or not to execute “non-injection injection valve drive control” again. This determination is made based on whether or not there is time to re-execute the “non-injection injection valve drive control” until the output of the drive pulse 61. When there is time until the output of the drive pulse 61, the pressure pulsation can be further added to the pressure pulsation generated last time by re-executing the “non-injection injection valve drive control”. For example, when the injection amount variation is large and the injection amount cannot be corrected sufficiently by only generating one pressure pulsation, the injection amount can be corrected to a predetermined target value by adding the pressure pulsation.
In S445, the ECU 18 executes “injection valve drive control” to inject fuel from the fuel injection valve 11.

  According to the injection amount control apparatus according to the second embodiment of the present invention described above, before injecting high-pressure fuel, the electromagnetic valve is opened within a range in which the valve element does not open, and pressure pulsation is generated in the pressure accumulation chamber of the common rail 13. Is generated. At this time, the phase of pressure pulsation is adjusted by adjusting the opening timing of the solenoid valve, so that the fuel pressure during fuel injection by the fuel injection valve 11 can be adjusted. Therefore, the fuel injection amount is stabilized.

  In the above embodiment, the pressure pulsation for canceling out the pressure pulsation generated in the pressure accumulating chamber and the pressure pulsation for adjusting the fuel pressure at the time of fuel injection are generated by using the fuel injection valve 11. This pressure pulsation may be generated using a fuel other than the fuel injection valve 11. For example, a pressure reducing valve may be provided in the pressure accumulation chamber or the supply line 12 of the common rail 13 and the pressure pulsation may be generated by opening and closing the pressure reducing valve. However, in that case, it is necessary to provide a pressure reducing valve separately from the fuel injection valve 11, and the number of parts increases. On the other hand, when the fuel injection valve 11 is used, those pressure pulsations can be generated without increasing the number of parts.

The present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the scope of the invention.

(A) And (B) is a schematic diagram which shows the pressure pulsation which generate | occur | produces in the pressure accumulation chamber which concerns on one Embodiment of this invention. The schematic diagram which shows the fuel-injection system which concerns on one Embodiment of this invention. Sectional drawing of the fuel injection valve which concerns on one Embodiment of this invention. The flowchart which concerns on one Embodiment of this invention. The flowchart which concerns on one Embodiment of this invention. (A)-(D) are the graphs for calculating | requiring the variation | change_quantity of the injection valve drive period, injection start delay time, injection valve drive period, and pressure accumulation chamber pressure which concern on one Embodiment of this invention. The flowchart which concerns on one Embodiment of this invention. (A)-(C) are schematic diagrams which show the pressure pulsation which generate | occur | produces in the pressure accumulation chamber which concerns on one Embodiment of this invention. The flowchart which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel injection system, 11 Fuel injection valve, 13 Common rail, 18 ECU (fuel injection means, pressure pulsation generation means, injection amount control apparatus), 33 Electromagnetic drive part (electromagnetic valve), 35 Injection hole, 36 Valve needle (valve body) 40) control room

Claims (15)

Fuel injection means for controlling a fuel injection valve for injecting high-pressure fuel introduced from the pressure accumulation chamber of the common rail;
Pressure pulsation generating means for generating a new pressure pulsation in the pressure accumulating chamber that cancels the pressure pulsation generated in the pressure accumulating chamber by the fuel injection by the fuel injection valve after injecting the high pressure fuel by the fuel injection means;
An injection amount control device comprising: The fuel injection valve includes: a valve body that opens and closes a nozzle hole that injects the high-pressure fuel; a control chamber in which the high-pressure fuel presses the valve body in a valve-closing direction; and the high-pressure fuel in the control chamber is allowed to escape It has a solenoid valve that opens the valve body,
The pressure pulsation generating means generates the new pressure pulsation by opening the electromagnetic valve within a range in which the valve body does not open after the high pressure fuel is injected from the injection hole by the fuel injection means. The injection amount control apparatus according to claim 1. The fuel injection means opens the solenoid valve by outputting a drive pulse to the solenoid valve,
The injection amount control device according to claim 2, wherein the pressure pulsation generating unit generates the new pressure pulsation by outputting a dummy pulse after the fuel injection unit outputs the drive pulse.   4. The injection amount control device according to claim 1, wherein the pressure pulsation generating means generates the new pressure pulsation only when the pressure pulsation in the pressure accumulating chamber is equal to or larger than a predetermined magnitude.   The injection amount control device according to any one of claims 1 to 4, wherein the pressure pulsation generating unit determines the size of the new pressure pulsation according to the size of the pressure pulsation in the pressure accumulating chamber.   The injection amount control device according to any one of claims 1 to 5, wherein the pressure pulsation generating unit generates the new pressure pulsation a plurality of times. A fuel injection stage for controlling a fuel injection valve that injects high-pressure fuel introduced from a common rail accumulator;
A pressure pulsation generating step of generating a new pressure pulsation in the pressure accumulating chamber that cancels a pressure pulsation generated in the pressure accumulating chamber by fuel injection by the fuel injection valve after injecting the high pressure fuel in the fuel injection step;
An injection amount control method including: Fuel injection means for controlling a fuel injection valve for injecting high-pressure fuel introduced from the pressure accumulation chamber of the common rail;
Pressure pulsation generating means for generating pressure pulsation in the pressure accumulating chamber before injecting the high-pressure fuel by the fuel injection means, and adjusting the phase of the pressure pulsation so that fuel at the time of fuel injection by the fuel injection valve Pressure pulsation generating means for adjusting the pressure;
An injection amount control device comprising: The fuel injection valve includes: a valve body that opens and closes a nozzle hole that injects the high-pressure fuel; a control chamber in which the high-pressure fuel presses the valve body in a valve-closing direction; and the high-pressure fuel in the control chamber is allowed to escape It has a solenoid valve that opens the valve body,
The pressure pulsation generating means generates a pressure pulsation in the pressure accumulating chamber by opening the electromagnetic valve in a range where the valve body does not open, and in the generation of the pressure pulsation, the pressure pulsation generating means The injection amount control device according to claim 8, wherein the phase of the pressure pulsation is adjusted by adjusting the valve opening timing. The fuel injection means opens the solenoid valve by outputting a drive pulse to the solenoid valve,
The injection amount control device according to claim 9, wherein the pressure pulsation generating unit generates the pressure pulsation by outputting a dummy pulse before the fuel injection unit outputs the drive pulse.   11. The injection amount control device according to claim 8, wherein the pressure pulsation generating means generates the pressure pulsation only when an injection amount variation of the fuel injection valve is outside an allowable range.   The injection amount control device according to any one of claims 8 to 11, wherein the pressure pulsation generating unit determines a phase of the pressure pulsation in accordance with an injection amount characteristic unique to the fuel injection valve.   The injection amount control device according to any one of claims 8 to 12, wherein the pressure pulsation generating means determines the magnitude of the pressure pulsation according to a fuel pressure in the pressure accumulating chamber.   The injection amount control device according to any one of claims 8 to 13, wherein the pressure pulsation generating unit generates the pressure pulsation a plurality of times. A fuel injection stage for controlling a fuel injection valve that injects high-pressure fuel introduced from a common rail accumulator;
A pressure pulsation generating step for generating pressure pulsation in the pressure accumulating chamber before injecting the high-pressure fuel in the fuel injection step, wherein the fuel during fuel injection by the fuel injection valve is adjusted by adjusting a phase of the pressure pulsation; A pressure pulsation generation stage for adjusting the pressure;
An injection amount control method including:

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