JP2014005793A - Control device for accumulator fuel injection apparatus, control method and accumulator fuel injection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a load on a control device for an accumulator fuel injection apparatus by adopting a method of learning an injector correction amount corresponding to the amount of deviation from a reference injection amount.SOLUTION: When a non-injection state is detected, minute injection is executed, and an injection amount for learning determination in a predetermined learning rail pressure is calculated. The injection amount for learning determination is compared with an allowable limit and an interpolation limit determining the range of the injection amount of a predetermined deviation amount from a reference injection amount, and a difference between the injection amount for learning determination and the reference injection amount is calculated as a differential injection amount. In the case where the injection amount for learning determination exceeds the interpolation limit and is within the allowable limit, on the basis of the differential injection amount in the previous and subsequent learning rail pressures, a correction amount of an injector is learnt. In the case where the injection amount for learning determination exceeds the allowable limit, injection for second learning is executed while changing an electrification time of the injector in the corresponding learning rail pressure, and second learning is executed for learning the correction amount of the injector on the basis of such an electrification time that a variation of a crank angular velocity becomes a reference variation.

Description

  The present invention relates to a control device and control method for an accumulator fuel injection device for injecting fuel into a cylinder of an internal combustion engine, and an accumulator fuel injection device. In particular, the present invention relates to a control apparatus and control method for an accumulator fuel injection apparatus and an accumulator fuel injection apparatus for correcting a deviation in fuel injection amount due to individual differences in injectors caused by manufacturing tolerances and deterioration.

  2. Description of the Related Art Conventionally, as a device for injecting fuel into a cylinder of an engine mounted on a vehicle or the like, a pressure accumulation type fuel injection device having a common rail for temporarily storing fuel pressurized by a high-pressure pump has been used. . A plurality of injectors are connected to the common rail, and fuel is injected into the cylinders of the engine at a desired injection timing by performing energization control of each injector while high-pressure fuel is supplied to each injector. The

  In recent years, in a diesel engine, a small amount of pilot injection is generally performed before main injection for the purpose of improving combustion characteristics of a fuel in a cylinder and reducing combustion noise and NOx. It has become. In carrying out this pilot injection, in order to sufficiently obtain the effect of reducing combustion noise and NOx, it is required to accurately control the injection amount of the minute injection. However, there may be a deviation between the target injection amount and the actual injection amount due to variations in injection characteristics for each injector caused by manufacturing tolerances and deterioration with time.

  As a control device that can learn the deviation of the injection amount and improve the accuracy of the fuel injection control, there is no cost increase due to additional equipment, and the fuel injection control of the diesel engine that can carry out the injection amount learning with high accuracy A device has been proposed. Specifically, at the time of no injection in which the command injection amount to the injector becomes zero, after the pressure in the common rail is set to a predetermined pressure, the fuel injection is performed a plurality of times while changing the energization time of the injector, and the internal combustion engine at that time A fuel injection control device configured to learn the energization time when the crank angular speed fluctuation amount becomes the reference fluctuation amount is disclosed (for example, see Patent Document 1).

JP 2011-256839 A

  However, in executing the control described in Patent Document 1, it is possible to increase learning accuracy by setting learning points for many common rail pressures, but on the other hand, too many learning points are provided. And there is a problem of increasing the load on the microcomputer of the control device. Further, even if the deviation of the fuel injection amount from the target value is small and the learning is performed even in a state where there is no influence on the combustion sound or the exhaust gas, the load on the microcomputer is increased.

  Therefore, the inventor of the present invention has made diligent efforts and, when a non-injection state is detected, executes a plurality of correction amount calculation injections with the reference injection amount as a target injection amount while changing the pressure in the common rail, The learning energization time correction value is calculated according to the difference between the learning determination injection amount at each learning pressure and the reference injection amount. It has been found that such problems can be solved by adopting the present invention, and the present invention has been completed. That is, an object of the present invention is to provide an accumulator type fuel injection device capable of minimizing an increase in a load on a microcomputer of a control device even when a learning point for learning an energization time correction value is increased. It is providing the control apparatus and control method of this, and a pressure accumulation type fuel-injection apparatus.

  According to the present invention, there is provided a control apparatus for an accumulator fuel injection apparatus that controls an accumulator fuel injection apparatus including a common rail to which a plurality of injectors are connected to execute fuel injection control into a cylinder of an internal combustion engine. When the injection state is detected, the correction amount calculation injection with the reference injection amount as the target injection amount is executed while changing the rail pressure of the common rail, and the learning determination injection amount at a predetermined learning rail pressure is set as the correction amount calculation injection. An injection amount for learning determination that is calculated from the injection amount, an allowable limit that determines a range of the injection amount that is a predetermined deviation from the reference injection amount, and an injection that is smaller than the allowable limit A learning necessity determination unit that determines whether or not learning is necessary by comparing with an interpolation limit that defines a range of the amount, and a differential injection amount that calculates a difference between the learning determination injection amount and the reference injection amount as a differential injection amount A first learning unit that learns the correction amount of the injector based on the difference injection amount in the learning rail pressure before and after the learning rail pressure when the injection amount for learning determination exceeds the interpolation limit and is within the allowable limit; When the learning determination injection amount exceeds the allowable limit, the second learning injection is executed while changing the energization time of the injector at the learning rail pressure, and the crank angular speed of the internal combustion engine when the second learning injection is executed. And a second learning unit that learns a correction amount of the injector based on an energization time in which the fluctuation amount becomes a reference fluctuation amount obtained by the reference injection amount. Provided.

  Further, in configuring the control device for the pressure accumulating fuel injection device according to the present invention, the first learning unit performs the correction based on the interpolation calculation from the difference injection amount in the learning rail pressure before and after the learning rail pressure for learning the correction amount. It is preferred to calculate the amount.

  Further, when configuring the control device for the accumulator fuel injection device according to the present invention, the first learning unit is configured such that the learning determination injection amount in the learning rail pressure before and after the learning rail pressure for learning the correction amount is within the interpolation limit. It is preferable to perform the interpolation calculation by forcibly assuming that the difference injection amount corresponding to the learning determination injection amount is zero.

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

  Another aspect of the present invention provides a control for an accumulator fuel injection device that controls an accumulator fuel injector provided with a common rail to which a plurality of injectors are connected to perform fuel injection control into a cylinder of an internal combustion engine. When a non-injection state is detected, correction amount calculation injection with the reference injection amount as a target injection amount is executed while changing the rail pressure of the common rail, and the learning determination injection amount at a predetermined learning rail pressure Is calculated from the injection amount of the correction amount calculation injection, and the learning determination injection amount is set to an allowable limit that defines a range of the injection amount that is a predetermined deviation amount from the reference injection amount, and an injection amount that is smaller than the allowable limit. The learning limit is determined by comparing with the interpolation limit that defines the range, the difference between the learning determination injection amount and the reference injection amount is calculated as the differential injection amount, and the learning determination injection amount exceeds the interpolation limit. If it is within the allowable limit, first learning is performed to learn the correction amount of the injector based on the differential injection amount at the learning rail pressure before and after the learning rail pressure, and if the learning determination injection amount exceeds the allowable limit, the learning is performed. The second learning injection is executed while changing the injector energizing time at the rail pressure, and the amount of fluctuation of the crank angular speed of the internal combustion engine when the second learning injection is executed becomes the reference fluctuation amount obtained by the reference injection quantity. A control method for an accumulator fuel injection control apparatus, wherein second learning for learning a correction amount of an injector is performed based on time.

  According to the control device and control method for an accumulator fuel injection device and the accumulator fuel injector according to the present invention, when a non-injection state is detected, a plurality of correction amount calculation injections using the reference injection amount as a target injection amount The learning determination injection amount at a predetermined learning pressure is calculated from the injection amount of the correction amount calculation injection, and the difference between the learning determination injection amount and the reference injection amount at each learning pressure is executed. By adopting an injector energization time correction value learning method according to the above, even if the learning points are increased, an increase in the load on the microcomputer of the control device can be minimized.

1 is an overall view showing a configuration example of a pressure accumulation fuel injection device in an embodiment of the present invention. It is a block diagram for demonstrating the control apparatus of the pressure accumulation type fuel injection apparatus in embodiment of this invention. It is a flowchart which shows an example of the procedure of the correction | amendment learning of the injector in embodiment of this invention. FIG. 4A is a diagram showing a change in injection amount at each pressure by injector correction learning in the embodiment of the present invention, FIG. 4A is an injection amount of correction amount calculation injection, and FIG. 4B is a learning determination injection. Indicates the amount. It is a figure which shows the injection quantity after correction | amendment learning in each pressure by the injection quantity correction | amendment learning in embodiment of this invention.

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

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

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

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

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

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

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

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

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

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

  The injector 17 includes a nozzle body provided with an injection hole and a nozzle needle that opens and closes the injection hole by advancing and retreating. The injector 17 closes the injection hole by applying a back pressure to the rear end side of the nozzle needle, while opening the injection hole by releasing the loaded back pressure. As the back pressure control means of the injector 17, an electrostrictive actuator provided with a piezo element or an electromagnetic solenoid actuator is used.

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

2. Control unit (ECU)
FIG. 2 is a functional block diagram showing a part related to learning control in the control device 50 for controlling the accumulator fuel injection device 10 of the present embodiment. The control device 50 is configured around a microcomputer having a known configuration, and includes an injector control unit 61, a non-injection state detection unit 62, a rail pressure control unit 63, an angular velocity detection unit 64, and learning control. The part 66 is provided as a main component. Specifically, these are realized by executing a program by a microcomputer. In addition, the control device 50 includes storage means such as a RAM (Random Access Memory) (not shown), and stores various pieces of read information and calculation results.

  Among these, the injector control unit 61 obtains the target injection amount Qtgt based on the engine speed Ne, the accelerator operation amount Acc, and the like, and based on the actual rail pressure Pr detected by the rail pressure sensor 25 and the target injection amount Qtgt. The energization time of the injector 17 is obtained, and an energization instruction is output to the actuator of the injector 17.

When the injector control unit 61 receives an instruction from the learning control unit 66 to execute a correction amount calculation injection described later, the injector control unit 61 calculates a plurality of correction amounts using the predetermined reference injection amount as a target value from the injector 17 that performs learning control. The fuel injection is performed once during one combustion cycle of the internal combustion engine while changing the rail pressure. Since the correction amount calculation injection is performed in a state where the target injection amount Qtgt is zero, the predetermined reference injection amount is a minute amount that does not greatly affect the output of the internal combustion engine, for example, 1 to ³ mm ³ / It is about st.

Further, when an instruction to execute second learning described later is received from the learning control unit 66, the injector control unit 61 performs one learning cycle from the injector 17 that performs learning control at a target learning rail pressure during one combustion cycle of the internal combustion engine. Minute injection is performed several times while changing the energization time. The injection for the second learning is performed in a state where the target injection amount Qtgt is zero, similar to the above-described correction amount calculation injection, and the injection amount does not greatly affect the output of the internal combustion engine. For example, about 1 to ³ mm ³ / st.

  The non-injection state detection unit 62 detects a non-injection state when the target injection amount Qtgt obtained by the injector control means 61 becomes zero.

  During normal operation, the rail pressure control unit 63 obtains a target value (hereinafter referred to as “target rail pressure”) Ptgt of the rail pressure based on the engine speed Ne, the accelerator operation amount Acc, etc. Based on the difference from the rail pressure Pr, the energization amount to at least one of the flow control valve 19 or the pressure control valve 23 is feedback-controlled.

  Further, when the non-injection state is detected by the non-injection state detection unit 62, the rail pressure control unit 63 is requested in the correction amount calculation injection or the second learning injection to be described later according to an instruction from the learning control unit 66. The rail pressure is controlled so that the rail pressure becomes the same.

  The angular velocity detector 64 continuously reads a sensor signal Sω of a crank angle sensor (not shown) every unit time, and detects the angular velocity Ω based on the rotational displacement of the crankshaft (not shown) per unit time. .

  When the non-injection state is detected, the learning control unit 66 instructs the injector control unit 61 to execute correction amount calculation injection, calculates the learning determination injection amount described later, learns necessity determination, and differential injection. Quantity calculation, first learning, and second learning are executed. In addition, the learning control unit 66 obtains the fuel injection amount when the minute injection by the injector 17 is executed based on the fluctuation amount of the angular velocity Ω detected by the angular velocity detection unit 64.

  Further, the learning control unit 66 learns the energization time correction value in first learning and second learning described later. Since the energization time of the injector 17 determined by the injector control means 61 is determined from the actual rail pressure Pr and the target injection amount Qtgt based on data such as a map created using the reference injector, the injector that is actually used Due to the individual difference between 17 and the reference injector, there may be a deviation between the target injection amount Qtgt and the actual injection amount Qact. This individual difference is caused by manufacturing variations or deterioration of individual injectors. In the first learning and the second learning, the energization time correction value is learned in order to eliminate such a deviation in the injection amount. In the control device 50 of the present embodiment, the obtained correction value is used for correcting the control amount of the injector 17 when the pilot injection is executed before the main injection.

3. Correction Value Learning Method Next, the injector correction value learning method executed by the control device 50 described above will be specifically described with reference to the flowchart of FIG. This process is repeatedly executed at a predetermined cycle during operation of the internal combustion engine.

  When processing by the control device 50 is started, first, in step S102, it is determined whether or not the internal combustion engine is in a non-injection state. If it is determined that there is no injection state (in the case of YES), the process proceeds to step S104. When it is determined that the injection state is not established (in the case of NO), the process once returns to the main routine (not shown). Here, the non-injection state is a state in which the target injection amount Qtgt determined by the injector control unit 61 becomes zero when the vehicle is decelerated or the like.

In step S104, correction amount calculation injection is performed. That is, the minute injection with the predetermined reference injection amount as the target injection amount is executed once in one combustion cycle of the internal combustion engine while changing the rail pressure. Further, the injection amount actually injected is calculated from the angular velocity fluctuation amount ΔΩ of the crankshaft (not shown) at that time. The correction amount calculation injection is performed for each injector. In the present embodiment, the reference injection amount as the target injection amount is 1 mm ³ / st.

  Next, the process proceeds to step S106, where it is determined whether or not the injection amount measurement of the correction amount calculation injection is completed for all the injectors to be used with all the rail pressures, and when it is determined that the measurement is completed ( In the case of YES), the process proceeds to step S108, while when it is determined that the measurement has not ended (in the case of NO), the process returns to step S104 and the injection amount measurement is continued.

  FIG. 4A is an example in which the injection amount of the correction amount calculation injection executed in step S104 is plotted for each rail pressure. In the present embodiment, the correction amount calculation injection is executed by changing the rail pressure every 2 MPa. Further, since the data corresponding to FIG. 4A exists for the number of used injectors, the processing from step S110 to step S122 below is performed for all the injectors.

  In step S108, the learning determination injection amount corresponding to each learning rail pressure is calculated from the injection amount of the correction amount calculation injection executed in step S104. In the present embodiment, the learning rail pressure is determined every 20 MPa between 40 MPa and 180 MPa. The learning determination injection amount corresponding to each learning rail pressure is an average value of the correction amount calculation injection amounts in the range of 10 MPa before and after the learning rail pressure. That is, when the case where the learning rail pressure is 40 MPa is taken as an example, the average value of the injection amounts for correction amount calculation from 30 MPa to 50 MPa becomes the learning determination injection amount at 40 MPa. The learning determination injection amount corresponding to each learning rail pressure calculated in this manner is shown in FIG. However, which rail pressure is used as the learning rail pressure, or how many MPa before and after the learning rail pressure the injection amount for learning determination is calculated can be determined as appropriate. Moreover, the injection amount of the correction amount calculation injection at each learning rail pressure can be used as the learning determination injection amount.

  Next, the process proceeds to step S110, and the injector and learning rail pressure to be learned this time are selected. As the learning rail pressure, any one of the learning rail pressures for which the learning determination injection amount is calculated in the previous step S108 is selected.

In step S112, the difference between the learning determination injection amount calculated in the previous step S108 and the reference injection amount is calculated as a differential injection amount. Here, the differential injection amount can take both positive and negative values. For example, at the learning rail pressure 40 MPa (point A) in FIG. 4B, the learning determination injection amount is 0.77 mm ³ / st. Because there is
Differential injection amount = 0.77 (learning determination injection amount) −1 (reference injection amount) = − 0.23 mm ³ / st
It becomes.

  In the subsequent step S114, it is determined whether or not the learning determination injection amount exceeds the interpolation limit. When the learning determination injection amount exceeds the interpolation limit (in the case of YES), the process proceeds to step S116, while when the learning determination injection amount is determined to be within the interpolation limit (in the case of NO), the reference injection of the learning determination injection amount. Since the deviation with respect to the amount is small and correction is not necessary, the process proceeds to step S122.

Here, the interpolation limit will be described with reference to FIG. The interpolation limit defines a range of the injection amount with a predetermined deviation amount from the reference injection amount to both positive and negative. In the present embodiment, the range of the injection amount defined by the interpolation limit is from 0.9 mm ³ / st to 1.1 mm ³ / st. Therefore, when the learning determination injection amount exceeds the interpolation limit, that is, in the case of YES in step S114, the learning determination injection amount is 0.9 mm ³ / st indicated by a one-dot chain line in FIG. And 1.1 mm ³ / st.

  In step S116, it is determined whether or not the learning determination injection amount exceeds an allowable limit. When the learning determination injection amount exceeds the allowable limit (in the case of YES), the process proceeds to step S118. On the other hand, when the learning determination injection amount is determined to be within the allowable limit (in the case of NO), the process proceeds to step S120.

Here, the allowable limit will be described with reference to FIG. The allowable limit defines a range of the injection amount with a predetermined deviation amount from the reference injection amount to both positive and negative. In the present embodiment, the range of the injection amount defined by the allowable limit is from 0.8 mm ³ / st to 1.2 mm ³ / st. Therefore, when the learning determination injection amount exceeds the allowable limit, that is, in the case of YES in step S116, the learning determination injection amount is 0.8 mm ³ / st and indicated by a broken line in FIG. This refers to the case of being outside the region sandwiched by 1.2 mm ³ / st.

  In step S118, the second learning is executed. In the second embodiment, the learning learning injection amount exceeds the interpolation limit and exceeds the allowable limit. Therefore, in the present embodiment, the points A and F in FIG. 4B are used. , And point G are targeted.

  The second learning is a known learning method that has been performed conventionally. That is, when the non-injection state is detected, the actual rail pressure Pr is controlled to the target rail pressure for executing the second learning, and from the injector 17 that performs the learning control, once in one combustion cycle of the internal combustion engine. Minute injection (second learning injection) is executed a plurality of times while changing the energization time ET. Further, since the angular velocity fluctuation amount ΔΩ of the crankshaft (not shown) at that time is detected by the angular velocity detector 64, the relationship between the energization time ET and the angular velocity fluctuation amount ΔΩ can be obtained. The learning control unit 66 can refer to the reference angular velocity fluctuation amount ΔΩ0 corresponding to the reference injection amount stored in advance in the control device 50, and the angular velocity fluctuation amount ΔΩ due to the second learning injection is used as the reference angular velocity fluctuation. The energization time ET_a when the amount becomes ΔΩ0 can be obtained.

  Thereafter, the learning control unit 66 reads the reference energization time ET_0 that is stored in the control device 50 and is measured using the reference injector, and in which the reference injection amount of fuel is injected at the learning rail pressure, and changes in the reference angular velocity fluctuation ΔET, which is the difference between energization times ET_a and ET_0 required to obtain the amount ΔΩ0, is acquired as a difference energization time learning value and stored in a predetermined map. After ΔET is acquired, the time corrected by the difference energization time ΔET is used as the energization time and fuel injection is executed.

  In step S120, the first learning is executed. Since the first learning is performed for the learning rail pressure at which the learning determination injection amount exceeds the interpolation limit and is within the allowable limit, in this embodiment, the points C and C in FIG. E and point H are targets.

  In the first learning, a learning value is obtained by interpolation calculation from the differential injection amount at the learning rail pressure before and after the target learning rail pressure. However, when performing this interpolation calculation, if the learning determination injection amount at the learning rail pressure before and after the target learning rail pressure is within the interpolation limit, the differential injection amount calculated from the learning determination injection amount is forced. The calculation is performed assuming that it is zero. Hereinafter, a specific learning method for the points C, E, and H, which is the target of the first learning in FIG.

First, the first learning for the point C will be described below. The injection quantity for learning determination at point C is 1.12 mm ³ / st from FIG. The learning rail pressures before and after the point C are 60 MPa (point B) and 100 MPa (point D), and the respective learning determination injection amounts are 0.97 mm ³ / st (point B) and 1.08 mm ³ / st (point D). Here, the injection quantity for learning determination at the points B and D is within the region sandwiched by the alternate long and short dash line in FIG. 4B, that is, within the interpolation limit. Therefore, the interpolation calculation is performed with each differential injection amount being forcibly regarded as zero. That is,
Interpolated value at point C = (differential injection amount at point B + differential injection amount at point D) / 2 = (0 + 0) / 2 = 0 mm ³ / st
As a result, the injection amount correction for the point C is not performed.

Next, the first learning for the point E will be described below. The learning determination injection amount at the point E is 1.11 mm ³ / st from FIG. The learning rail pressures before and after point E are 100 MPa (point D) and 140 MPa (point F), and the respective learning determination injection amounts are 1.08 mm ³ / st (point D) and 1.24 mm ³ / st (point F). Here, the learning determination injection amount at the point D is within a region sandwiched by an alternate long and short dash line in FIG. 4B, that is, within the interpolation limit. Therefore, in performing this interpolation calculation, the differential injection amount at the point D is forcibly regarded as zero. Further, the differential injection amount at the point F is calculated by the difference between the learning determination injection amount and the reference injection amount. Therefore, the differential injection amount at point D and point F is
Differential injection amount at point D → 0 mm ³ / st
Differential injection amount at point F = 1.24−1 = 0.24 mm ³ / st
It becomes. Therefore, the interpolation value of point E is
Interpolated value at point E = (differential injection amount at point D + differential injection amount at point F) / 2 = (0 + 0.24) /2=0.12 mm ³ / st
It becomes.

The post-learning target injection amount for the point E after the actual learning is performed is calculated by subtracting the interpolation value from the reference injection amount,
Target injection amount after learning of point E = 1 (reference injection amount) −0.12 (interpolated value) = 0.88 mm ³ / st
It becomes.

When the post-learning target injection amount at the point E is obtained, the injector control unit 61 obtains the post-learning energization time corresponding to this and performs the subsequent injection. In addition, by this learning, the actual post-learning injection amount at point E is
Injection amount after learning = 1.11 (injection amount for learning determination) −0.12 (interpolation value) = 0.99 mm ³ / st
It becomes.

Next, the first learning for the point H will be described below. The learning determination injection amount at the point H is 1.18 mm ³ / st from FIG. Point H is the highest learned rail pressure in this embodiment. In this case, the differential injection amount on the high rail pressure side is regarded as zero among the differential injection amounts used for the interpolation calculation. On the other hand, the differential injection amount for the point G on the low rail pressure side is calculated by the difference between the learning determination injection amount and the reference injection amount. Therefore, the differential injection amount at point G is
Differential injection amount at point G = 1.26−1 = 0.26 mm ³ / st
Therefore, the interpolation value of point H is
Interpolated value at point H = (difference injection amount at point G + 0) / 2 = (0.26 + 0) /2=0.13 mm ³ / st
It becomes. Hereinafter, as in the case of point E,
Target injection amount after learning of point H = 1 (reference injection amount) −0.13 (interpolated value) = 0.87 mm ³ / st
Injection amount after learning at point H = 1.18 (injection amount for learning determination) −0.13 (interpolation value) = 1.05 mm ³ / st
It becomes.

  In the present embodiment, the point A, which is the lowest learning rail pressure, is the object of the second learning. However, if the point A is the object of the first learning, the differential injection used for the interpolation calculation Of the amount, the difference injection amount on the low rail pressure side is regarded as zero, and learning similar to the first learning for the point G is executed.

  Further, in the first learning, all the learning determination injection amounts used for the interpolation calculation are larger than the reference injection amount, but even when the learning determination injection amount is smaller than the reference injection amount. Learning can be done in the same way.

  When the first learning or the second learning is completed, the process proceeds to step S122, and the learning result is stored in an appropriate area of the microcomputer of the control device.

  In subsequent step S124, it is determined whether or not learning has been completed for all the injectors and the learning rail pressure. If it is determined that learning has not been completed (in the case of NO), the process returns to step S110. On the other hand, if it is determined that the learning is completed (YES), the process returns to the main routine (not shown).

FIG. 5 is a diagram in which the injection amount after learning is plotted in the present embodiment. Prior to the main learning, second learning was performed for points A, F, and G (see FIG. 4B) where the learning determination injection amount exceeded the allowable limit. As a result, the injection amount after learning is 1 mm ³ / st which matches the reference injection amount.

  In addition, for the points C, E, and H (see FIG. 4B) that the learning determination injection amount exceeds the interpolation limit and is within the allowable limit before the main learning, the first learning is performed. Was implemented. As a result, since the complementary value at point C is 0, the injection amount does not change before and after learning. Moreover, about the point E and the point H, the injection quantity after learning is approaching the reference | standard injection quantity.

  Further, before the learning, since the learning was not performed for the points B and D (see FIG. 4B) where the learning determination injection amount was equal to or less than the interpolation limit, the injection amount was changed. Absent.

  As described above, as a result of learning of the present embodiment, the learning injection amount after learning at all learning points does not coincide with the reference injection amount, but generally approaches the reference injection amount. On the other hand, by introducing the first learning, which is a simpler learning method than before, the load on the computer of the control device is reduced, and it is possible to increase the number of learning points than before.

In the first learning of the present embodiment, for example, the learning determination injection amount at the target learning rail pressure falls below the interpolation limit range within the allowable limit range, that is, 0.8 mm ³ in FIG. 4B. When the learning injection amount of the learning rail pressure before and after the dashed line indicating / st and 0.9 mm ³ / st exceeds the interpolation limit range, It is possible in calculation that the post-learning injection amount is further away from the reference injection amount to the injection amount decreasing side. However, in fact, this is unlikely to happen for the following reasons.

  As a main example of the cause of the injection amount deviation due to the manufacturing variation and deterioration of the injector, there may be a variation in the sliding gap of the movable part, the nozzle sheet diameter, the nozzle hole diameter, etc. When viewed macroscopically, there may be a difference in sensitivity between the low rail pressure side and the high rail pressure side, but the injection amount does not greatly increase or decrease within a relatively narrow rail pressure range. That is, when the injection amount shifts to the increasing side, the injection amount at the surrounding rail pressure also tends to shift to the increasing side, and when the injection amount shifts to the decreasing side, the injection amount at the surrounding rail pressure also similarly There is a tendency to shift to a decreasing side.

  In other words, the present invention can be said to be in line with the tendency of actual injection amount deviation caused by manufacturing variations and deterioration of the injector to be corrected.

  Further, in the present embodiment, in determining the correction limit and the allowable limit at each learning rail pressure, the deviation amount from the reference injection amount is uniform, but considering the sensitivity of the influence on the exhaust, etc., for each learning rail pressure, Different limit values can be used.

1: Fuel tank, 10: Accumulated fuel injection device, 11: Low pressure pump, 13: High pressure pump, 13a: Pressurization chamber, 14: Cam, 15: Common rail, 17: Injector, 19: Flow control valve, 23: Pressure Control valve, 25: Rail pressure sensor, 27: Fuel intake valve, 28: Fuel discharge valve, 29: Plunger, 31: Low pressure fuel passage, 33, 35: High pressure fuel passage, 37, 38, 39: Return passage, 50: Control device 61: Injector control unit 62: Non-injection state detection unit 63: Rail pressure control unit 64: Angular velocity detection unit 66: Learning control unit

Claims (5)

In a control apparatus for an accumulator fuel injection apparatus that controls an accumulator fuel injection apparatus having a common rail to which a plurality of injectors are connected to perform fuel injection control into a cylinder of an internal combustion engine.
When a non-injection state is detected, correction amount calculation injection using the reference injection amount as a target injection amount is executed while changing the rail pressure of the common rail, and the learning determination injection amount at a predetermined learning rail pressure is set to the correction amount. An injection amount calculation unit for learning determination that is calculated from the injection amount of the injection for calculation;
Learning is performed by comparing the learning determination injection amount with an allowable limit that defines a range of an injection amount that is a predetermined deviation from the reference injection amount and an interpolation limit that defines a range of an injection amount that is smaller than the allowable limit. A learning necessity determination unit that determines whether or not
A difference injection amount calculation unit that calculates a difference between the learning determination injection amount and the reference injection amount as a difference injection amount;
A first learning unit that learns a correction amount of the injector based on the differential injection amount at a learning rail pressure before and after the learning rail pressure when the learning determination injection amount exceeds the interpolation limit and is within the allowable limit When,
When the learning determination injection amount exceeds the allowable limit, the second learning injection is executed while changing the energization time of the injector at the learning rail pressure, and the second learning injection is executed. A pressure accumulating fuel injection system comprising: a second learning unit that learns a correction amount of the injector based on an energization time in which a fluctuation amount of an engine crank angular speed becomes a reference fluctuation amount obtained by the reference injection amount. Control device control device.   2. The pressure accumulation according to claim 1, wherein the first learning unit calculates the correction amount based on an interpolation calculation from a differential injection amount at a learning rail pressure before and after the learning rail pressure for learning the correction amount. Type fuel injection device control device.   When the learning determination injection amount at the learning rail pressure before and after the learning rail pressure for learning the correction amount is within the interpolation limit, the first learning unit calculates a difference injection amount corresponding to the learning determination injection amount. The control apparatus for an accumulator fuel injection apparatus according to claim 2, wherein the interpolation calculation is performed by forcibly assuming zero.   An accumulator fuel injection device comprising the control device according to any one of claims 1 to 3. A control method for an accumulator fuel injection apparatus for controlling an accumulator fuel injection apparatus having a common rail to which a plurality of injectors are connected to execute fuel injection control into a cylinder of an internal combustion engine,
When a non-injection state is detected, correction amount calculation injection using the reference injection amount as a target injection amount is executed while changing the rail pressure of the common rail, and the learning determination injection amount at a predetermined learning rail pressure is set to the correction amount. Calculate from the injection amount of calculation injection,
By comparing the learning determination injection amount with an allowable limit that defines a range of an injection amount that is a predetermined deviation from the reference injection amount, and an interpolation limit that defines a range of the injection amount that is smaller than the allowable limit. Determine the necessity of learning,
Calculating the difference between the learning determination injection amount and the reference injection amount as a differential injection amount;
When the learning determination injection amount exceeds the interpolation limit and is within the allowable limit, first learning is performed to learn the correction amount of the injector based on the differential injection amount at the learning rail pressure before and after the learning rail pressure. Done
When the learning determination injection amount exceeds the allowable limit, the second learning injection is executed while changing the energization time of the injector at the learning rail pressure, and the internal combustion engine when the second learning injection is executed Control of the accumulator fuel injection control apparatus, wherein second learning for learning the correction amount of the injector is performed based on an energization time in which a fluctuation amount of the crank angular speed of the engine becomes a reference fluctuation amount obtained by the reference injection amount Method.

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