WO2011125371A1 - Fuel injection control device and pressure accumulation type fuel injection device - Google Patents

Fuel injection control device and pressure accumulation type fuel injection device Download PDF

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Publication number
WO2011125371A1
WO2011125371A1 PCT/JP2011/052802 JP2011052802W WO2011125371A1 WO 2011125371 A1 WO2011125371 A1 WO 2011125371A1 JP 2011052802 W JP2011052802 W JP 2011052802W WO 2011125371 A1 WO2011125371 A1 WO 2011125371A1
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WO
WIPO (PCT)
Prior art keywords
injector
fuel injection
pressure
injection
target
Prior art date
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PCT/JP2011/052802
Other languages
French (fr)
Japanese (ja)
Inventor
須田　栄
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ボッシュ株式会社
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Priority to JP2012509340A priority Critical patent/JPWO2011125371A1/en
Publication of WO2011125371A1 publication Critical patent/WO2011125371A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/3809—Common rail control systems
    • F02D41/3836—Controlling the fuel pressure
    • F02D41/3863—Controlling the fuel pressure by controlling the flow out of the common rail, e.g. using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
    • F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
    • F02M63/023—Means for varying pressure in common rails
    • F02M63/0235—Means for varying pressure in common rails by bleeding fuel pressure
    • F02M63/025—Means for varying pressure in common rails by bleeding fuel pressure from the common rail
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
    • F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails
    • F02M63/0265—Pumps feeding common rails
    • F02M63/027—More than one high pressure pump feeding a single common rail

Definitions

  • the present invention relates to a fuel injection control device and a pressure accumulation fuel injection device for performing fuel injection control to a cylinder of an internal combustion engine.
  • the present invention relates to a fuel injection control device and an accumulator fuel injection device that control an actual fuel injection amount to a calculated target fuel injection amount.
  • a fuel injection device that injects fuel into a cylinder of an internal combustion engine
  • a common rail that temporarily accumulates fuel pumped by a high-pressure pump and supplies fuel adjusted to a predetermined pressure to a plurality of injectors
  • the pressure accumulation type fuel injection device provided is used.
  • the injector is configured such that fuel is injected by opening an injection hole by energization control by a control device.
  • the energization time for the injector is obtained from the basic injection amount map information based on the pressure of the fuel supplied to the injector and the target fuel injection amount.
  • the target fuel injection amount is obtained by calculation based on, for example, the rotation speed of the internal combustion engine (hereinafter referred to as “engine rotation speed”) and the accelerator operation amount.
  • engine rotation speed the rotation speed of the internal combustion engine
  • accelerator operation amount the accelerator operation amount.
  • the energization time to the injector is detected by a pressure sensor or the like using basic injection amount map information indicating the relationship between the pressure in the common rail (hereinafter referred to as “rail pressure”), the energization time, and the fuel injection amount. Determined based on the pressure in the common rail (hereinafter referred to as “actual rail pressure”) and the target fuel injection amount.
  • a fuel injection device In a fuel injection device, if the fuel injection amount injected into the cylinder is excessive or insufficient with respect to the target fuel injection amount, there is a risk of causing exhaust emission, deterioration of operability, etc. It is desired that fuel injection be performed without excess or deficiency with respect to the amount.
  • injection characteristics the relationship between the energization time of each injector and the fuel injection amount due to variations in machining accuracy. It cannot be avoided. Therefore, there has been proposed a fuel injection control device configured to set a correction value for fuel injection according to the injection characteristics of the injector. More specifically, when the learning condition is satisfied, a learning operation is performed in which fuel injection is performed once and the actual fuel injection amount is detected from the state change amount of the internal combustion engine after the injection, while the energization time of the fuel injection valve is changed.
  • a fuel injection control apparatus that is executed a plurality of times and that calculates the energization time correction value for controlling the fuel injection amount to the target fuel injection amount by estimating the injection characteristics of the fuel injection valve from the detection result.
  • a fuel injection control apparatus that is executed a plurality of times and that calculates the energization time correction value for controlling the fuel injection amount to the target fuel injection amount by estimating the injection characteristics of the fuel injection valve from the detection result.
  • the fuel injection control device described in Patent Document 1 controls the fuel injection amount by correcting the energization time. If the flow rate of the fuel that passes through the nozzle of the injector matches the reference injector that is the reference for obtaining the target fuel injection amount, the energization time is corrected according to the control method described in Patent Document 1.
  • the waveform of the injection flow rate of the injector at a certain point in the injection period (hereinafter, this injection flow rate is referred to as the “injection rate of the injector”) is the waveform when the target fuel injection amount is injected by the reference injector. Can match.
  • injection rate characteristic the fuel injection amount characteristic per unit time of the injector
  • FIG. 13 shows a current waveform and an injection rate waveform when fuel injection by the injector is executed.
  • an injector hereinafter referred to as “lower limit product” in which the flow rate of fuel passing through the nozzle under a predetermined reference pressure (hereinafter referred to as “nozzle hydraulic flow rate”) indicates a lower limit value of tolerance.
  • Injection rate waveform is indicated by a one-dot chain line
  • the injection rate waveform of an injector hereinafter referred to as “upper limit product” in which the nozzle hydraulic flow rate indicates the upper limit of tolerance is indicated by a dotted line
  • the nozzle hydraulic flow rate is tolerance
  • the injection rate waveform of an injector hereinafter referred to as “central product”) indicating the median value of is indicated by a solid line.
  • the fuel injection by the injector starts after a while from the start of energization to the injector and ends after a while after the energization stops.
  • a value obtained by integrating the injection rate from the start point to the end point of fuel injection corresponds to the fuel injection amount.
  • the injection rate at a certain point in the injection period becomes lower as the hydraulic flow rate of the nozzle is smaller, and even when the same current waveform is applied, the smaller the injector, the lower the hydraulic flow rate of the nozzle. The injection amount is reduced.
  • the injection end time of the lower limit product and the upper limit product cross over the injection end time of the central product, respectively.
  • the injection time of the lower limit product is longer than that of the central product. If the injection time is longer than the injection time by the reference injector, there is a possibility that exhaust emission is deteriorated in the internal combustion engine.
  • the inventors of the present invention have made diligent efforts to correct the fuel injection amount by solving the problem by adjusting the rail pressure so that the injection rate characteristic of the injector approximates the injection rate characteristic of the reference injector.
  • the present invention has been found and completed. That is, the present invention aims to provide a fuel injection control device and an accumulator fuel injection device that can control the actual fuel injection amount to the target fuel injection amount without extending the injection time beyond the injection time by the reference injector.
  • the target fuel injection amount is based on the operating state of the internal combustion engine.
  • Target injection amount calculating means for calculating the target pressure
  • target rail pressure calculating means for calculating the target pressure in the common rail based on the operating state of the internal combustion engine
  • rail pressure detecting means for detecting the pressure in the common rail
  • Rail pressure control means for controlling the fuel
  • storage means for storing basic injection amount map information indicating the relationship between the pressure in the common rail, the energization time, and the fuel injection amount, which is created using the reference injector
  • the reference injector Correction method for correcting the control amount of the target pressure or rail pressure control means based on the difference between the injection rate characteristic and the injection rate characteristic of the injector
  • an injector control means for determining the energization time based on the basic injection amount map information and executing drive control of the injector. it can.
  • the correction means corrects the control amount of the target pressure or the rail pressure control means so that the peak of the injection rate of the reference injector matches the peak of the injection rate of the injector. It is preferable to do.
  • the correcting means converts the ratio of the flow rate of the reference injector nozzle and the flow rate of the injector nozzle under a predetermined pressure into a pressure ratio value obtained by converting the ratio. Based on this, it is preferable to obtain the correction amount of the control amount of the target pressure or rail pressure control means.
  • the predetermined pressure is an allowable maximum pressure of the common rail that can be realized in the accumulator fuel injection device.
  • a correction coefficient for making the injection rate of the injector coincide with the injection rate of the reference injector based on the injection rate of the reference injector and the injection rate of the injector under a predetermined pressure It is preferable that the correction means is obtained in advance and the correction means corrects the control amount of the target pressure or the rail pressure control means using the correction coefficient.
  • the injection rate of the injector or the passage flow rate of the nozzle is obtained in advance for each individual injector in the manufacturing stage of the injector.
  • the injector performs fuel injection by separating a needle valve that can be separated from and brought into contact with the seat surface of the nozzle. , A first period in which the injection flow rate of the injector is governed by the lift amount of the needle valve, and a second period in which the injection flow rate of the injector is governed by the nozzle hole area. In the case of the period, it is preferable that the correction unit corrects the control amount of the target pressure or the rail pressure control unit.
  • the target injection amount calculation means or the injector control means is configured so that the target fuel injection amount is based on the difference information between the reference fuel injection amount by the reference injector and the actual fuel injection amount by the injector. Alternatively, it is preferable to correct the control amount of the injector control means.
  • the injector control means uses the assumed rail pressure when correction is not performed, which is obtained based on the pressure in the common rail detected by the rail pressure detection means. It is preferable to obtain the energization time.
  • the storage means stores a plurality of injection quantity map information corresponding to the injection rate characteristics in addition to the basic injection quantity map information, and the injector control means It is preferable to select the injection amount map information corresponding to the injection rate characteristic to obtain the energization time.
  • Another aspect of the present invention includes a high-pressure pump that pressurizes and pumps fuel, a common rail that accumulates fuel pumped by the high-pressure pump, and a plurality of injectors connected to the common rail.
  • An accumulator fuel injection device comprising any one of the fuel injection control devices.
  • the pressure accumulation type fuel injection device of the present invention it is preferable to provide injectors having similar injection rate characteristics as the plurality of injectors.
  • the rail pressure is adjusted so that the injection rate characteristic of the injector approximates the injection rate characteristic of the reference injector, and the injector mounted on the internal combustion engine
  • the influence of variation between the injection rate and the injection rate of the reference injector used for creating the basic injection amount map information is reduced. Therefore, the fuel injection amount can be controlled to the target fuel injection amount while changing the injection time as much as possible. Therefore, the correction of the fuel injection amount that suppresses the deterioration of the exhaust emission is executed. Further, if such correction of the fuel injection amount becomes possible, the manufacturing tolerance of the nozzle hydraulic flow rate can be widened in the injector manufacturing stage, and the manufacturing efficiency of the injector can be improved.
  • FIG. 1 shows an example of the configuration of an accumulator fuel injection device 50 according to the first embodiment of the present invention.
  • An accumulator fuel injection apparatus 50 shown in FIG. 1 is an accumulator fuel injection apparatus that injects fuel into a cylinder of a diesel engine as an internal combustion engine 40, and includes a fuel tank 1, a low pressure pump 2, and a high pressure pump 5. And common rail 10, injector 13, control device 70, and the like as main components.
  • the basic configuration of the pressure accumulating fuel injection apparatus 50 is merely a conventionally known configuration, and a part of the configuration may be different.
  • the low pressure pump 2 sucks up the fuel in the fuel tank 1 and pumps it to the high pressure pump 5.
  • the high pressure pump 5 pressurizes the fuel pumped by the low pressure pump 2 and pumps it to the common rail 10.
  • a flow rate control valve 8 is provided on the upstream side of the pressurizing chamber 5a of the high-pressure pump 5, and according to the operating state of the internal combustion engine 40 and a target value of rail pressure (hereinafter referred to as “target rail pressure”).
  • target rail pressure a target rail pressure
  • the flow rate of the fuel flowing into 5a can be adjusted.
  • An overflow valve 14 is connected upstream of the flow rate control valve 8, and the pressure of the fuel pumped by the low pressure pump 2 is adjusted to a predetermined pressure.
  • the common rail 10 temporarily accumulates high-pressure fuel pumped from the high-pressure pump 5, and a plurality of connected injectors (hereinafter, the injectors used in the pressure-accumulation fuel injection device 50 are referred to as “actual injectors”). High pressure fuel is supplied to 13.
  • the common rail 10 is provided with a rail pressure sensor 21 and a pressure control valve 12 for detecting the rail pressure.
  • the pressure control valve 12 may be a safety valve, in the present embodiment, an electromagnetic control valve that controls the flow rate of the flow by the control device 70 is used, and the fuel in the common rail 10 according to the target rail pressure.
  • the discharge flow rate is adjustable.
  • the injector 13 controls the advancing and retreating movement of the nozzle needle by controlling the nozzle provided with the injection hole, the nozzle needle that can be separated from and contacting the seat surface of the nozzle, and the back pressure acting on the rear end side of the nozzle needle. And a back pressure control valve.
  • the injector 13 includes, for example, an electromagnetic control type injector in which an electromagnetic solenoid is used as a back pressure control valve, and an electrostriction type injector in which a piezo actuator is used as a back pressure control valve. Any injector can be used. can do.
  • the injector 13 has a configuration in which the lift amount of the needle valve changes depending on the energization time of the back pressure control valve, but in the first period (the seat restricting region) where the energization time is short, the lift amount of the needle valve
  • the fuel passage area defined by the nozzle seating surface and the needle valve is smaller than the total area of the injection holes. Therefore, in the first period of energization time, the injection flow rate of the injector 13 is governed by the lift amount of the needle valve.
  • the lift amount of the needle valve becomes large, and the fuel passage area defined by the seat surface of the nozzle and the needle valve is larger than the total area of the injection holes. Become. Therefore, in the second period of the energization time (injection aperture region), the injection flow rate of the injector 13 is governed by the total area of the injection holes.
  • the injector 13 when the injector 13 is produced by mass production, variations in the machining accuracy of each part are inevitable.
  • the flow rate of the fuel passing through the nozzle through the injection hole varies for each injector 13 due to the variation of the injection hole even if the fuel has the same pressure.
  • the flow rate of the fuel that passes through the nozzle affects the injection rate of the injector 13, and becomes a factor that causes variations in the fuel injection amount particularly in the second period (injection aperture restriction region) of the energization time.
  • FIG. 2 shows the relationship between the energization time ET and the fuel injection amount Qact of the injectors 13 of the upper limit product, the central product, and the lower limit product under the respective pressures in the low pressure state, the intermediate pressure state, and the high pressure state.
  • the first period sheet restriction region
  • the second period injection hole constriction region
  • a difference occurs in the injection rate due to the variation in the shape of the injection hole. Therefore, the injection was executed with the same energization time ET under the same pressure. Even in this case, the injection amount of the injector 13 for each of the upper limit product, the center product, and the lower limit product varies.
  • the flow rate of fuel (hydraulic flow rate) passing through each nozzle under a predetermined pressure is inspected.
  • the injector 13 is provided in each cylinder of the internal combustion engine 40.
  • all of the injectors 13 used in the accumulator fuel injection device 50 of the present embodiment have an approximation of the nozzle hydraulic flow rate, that is, the injection.
  • the rate characteristic is approximated. If a plurality of injectors 13 having similar injection rate characteristics are used, the fuel injection amount becomes equal as long as the rail pressure and the energization time are the same. No need for high processing power.
  • FIG. 3 is a block diagram functionally showing a part related to fuel injection amount correction control in the configuration of the control device 70 of the present embodiment.
  • the control device 70 is configured around a microcomputer having a known configuration, and includes a target injection amount calculation unit 71, a target rail pressure calculation unit 73, a rail pressure detection unit 75, and a rail pressure control unit 77.
  • a correction unit 79 and an injector control unit 81 are provided. Specifically, each of these units is realized by executing a program by a microcomputer.
  • control device 70 is provided with storage means (not shown) such as RAM (Random Access Memory), and various information is stored in the storage means in advance, or information read by other units, The calculation result is stored.
  • storage means such as RAM (Random Access Memory)
  • RAM Random Access Memory
  • various information is stored in the storage means in advance, or information read by other units, The calculation result is stored.
  • the engine speed signal from the rotation speed sensor 44 provided in the internal combustion engine 40, and the accelerator sensor In addition to the accelerator operation amount signal, sensor signals from other sensors are input.
  • the target injection amount calculation unit 71 is configured to read the engine speed Ne and the accelerator operation amount Acc and calculate the target fuel injection amount Qtgt.
  • the target rail pressure calculation unit 73 is configured to calculate the target rail pressure Prail_tgt based on the calculated target fuel injection amount Qtgt and the engine speed Ne.
  • the rail pressure detection unit 75 is configured to read a rail pressure signal from the rail pressure sensor 21 and detect the actual rail pressure Prail_act.
  • the correction unit 79 is configured to calculate the target rail pressure based on the difference between the injection rate characteristic of the reference injector BaseInj used as the reference of the basic injection amount map information BaseQmap stored in the storage unit and the injection rate characteristic of the actual injector 13.
  • the target rail pressure Prail_tgt obtained at 73 is corrected, and the corrected target rail pressure Prail_current is obtained.
  • the target rail pressure Prail_tgt is corrected, for example, so that the peak of the injection rate of the actual injector 13 during the injection period coincides with the peak of the injection rate of the reference injector BaseInj.
  • the peak value of the injection rate of the injector is defined by the hydraulic flow rate Qhydr of the nozzle, and this hydraulic flow rate Qhydr is a constant ⁇ times the square root of the pressure P (the following formula (1)).
  • Qhydr ⁇ ⁇ ⁇ P (1)
  • the pressure P corresponds to the difference between the pressure on the nozzle seat side and the pressure on the injection hole outlet side.
  • the pressure P is constant.
  • the variation of Qhydr is considered to be due to the variation of the constant ⁇ .
  • This variation in the constant ⁇ is caused by nozzle performance factors represented by the inlet diameter and outlet diameter of the injection hole, the curvature radius on the injection hole inlet side and the curvature radius on the outlet side, the flow coefficient of the fuel passing through the injection hole, and the like. Includes variation.
  • the ratio between the hydraulic flow rate Qhydr_Base of the nozzle of the reference injector BaseInj and the hydraulic flow rate Qhydr_inj of the nozzle of the actual injector 13 is converted into a pressure ratio to obtain a correction coefficient X, and multiplied by the target rail pressure Prail_tgt. Correction is performed.
  • the hydraulic flow rate measured when the injector is manufactured.
  • the target rail pressure Prail_tgt is multiplied by the pressure ratio obtained by converting the ratio of Qhydr_Base and Qhydr_inj.
  • the hydraulic flow rate Qhydr_Base of the reference injector BaseInj and the hydraulic flow rate Qhydr_inj of the actual injector 13 can be expressed by the following equations (2) and (3).
  • Qhydr_Base ⁇ base ⁇ ⁇ Pbase (2)
  • Qhydr_inj ⁇ inj ⁇ ⁇ Prail_current (3)
  • ⁇ base Constant due to tolerance of hydraulic flow rate of nozzle of reference injector
  • ⁇ inj Constant due to tolerance of hydraulic flow rate of nozzle of actual injector 13
  • the correction coefficient X ⁇ ( ⁇ base / ⁇ inj) 2 in the above equation (5).
  • ⁇ Can be set in advance. If the correction coefficient X corresponding to the actual injector 13 is set, the correction unit 79 substitutes the target rail pressure Prail_tgt calculated by the target rail pressure calculation unit 73 for Pbase in the above equation (5), and the corrected target The rail pressure Prail_current can be obtained.
  • the injection rate characteristic of the actual injector 13 is greater than the injection rate characteristic of the reference injector BaseInj. Even if it is high or low, the injection rate waveform can be approximated to the injection rate waveform of the reference injector BaseInj as shown in FIG. As a result, the fuel injection amount Qact of the reference injector 13 can be controlled to the target fuel injection amount Qtgt.
  • the hydraulic flow rate Qhydr of the nozzle required in the manufacturing stage is preferably at least the hydraulic flow rate under the actual working pressure.
  • the increase rate of the fuel injection amount Qact with the energization time ET increases as the rail pressure increases. In other words, when the same amount of fuel is injected in each of the upper limit product, the central product, and the lower limit product, the variation in the injection time is noticeable when the rail pressure is high and the fuel injection amount is large. .
  • the nozzle hydraulic flow rate Qhydr is set under the condition including the allowable maximum pressure that can be realized in the accumulator fuel injector 50. It is preferable to measure.
  • the fuel injection amount when the fuel injection is executed in the energization time corresponding to the full lift region of the needle valve is experimentally determined at two or more different energization times. It is preferable to determine the hydraulic flow rate Qhydr per unit time by determining and dividing the difference in fuel injection amount by the difference in injection time.
  • the hydraulic flow rate Qhydr of each injector 13 is obtained, and the injectors 13 are classified according to the tolerance. Then, when assembling the accumulator fuel injector 50, all the actual injectors 13 are constituted by the same class of injectors 13, and the correction coefficient X when correcting the target rail pressure Prail_tgt is in accordance with the tolerance of the hydraulic flow rate Qhydr. To the control device 70. Thus, when the target rail pressure Prail_tgt is obtained by the target rail pressure calculation unit 73, the correction unit 79 multiplies the target rail pressure Prail_tgt by the correction coefficient X to obtain the corrected target rail pressure Prail_current.
  • the rail pressure control unit 77 includes a flow rate control valve control unit 77a and a pressure control valve control unit 77b, and can control rail pressure by either one of the control units or by using both control units in combination. It is configured. Which control unit executes the control of the rail pressure is determined by the operating state of the internal combustion engine 40. This basic control of the rail pressure is executed by feedback-controlling the current value supplied to the flow control valve 8 or the pressure control valve 12 so that the actual rail pressure Prail_act becomes the corrected target rail pressure Prail_current. In the present embodiment, feedback control is executed using the corrected control rail value Prail_current obtained by the correction unit 79.
  • the injector control unit 81 is configured to determine the energization time ET of the injector 13 based on the basic injection amount map information BaseQmap stored in advance in the storage means and execute drive control of the injector 13.
  • the basic injection amount map information BaseQmap is a map of the relationship among the rail pressure Prail, the energization time ET, and the fuel injection amount Q, and is created in advance using the reference injector BaseInj.
  • the reference injector BaseInj for example, a central injector having a median injection rate characteristic is used. However, an injector other than the central injector may be the reference injector BaseInj.
  • the actual rail pressure Prail_act detected by the rail pressure detection unit 75 is basically used.
  • the corrected target rail obtained by correcting the target rail pressure Prail_tgt is used. Since rail pressure control is executed by the pressure Prail_current, the actual rail pressure Prail_act cannot be used as it is. If the actual rail pressure Prail_act is used as it is, the energization time ET is obtained with the variation in the injection rate characteristic included.
  • the injector control unit 81 multiplies the actual rail pressure Prail_act by the reciprocal (1 / X) of the correction coefficient X used for correcting the target rail pressure Prail_tgt to obtain the assumed rail pressure Prail_cal, and based on this assumed rail pressure Prail_cal. It is configured to obtain the energization time ET.
  • the required energization time ET is substantially equal to the energization time according to the actual rail pressure Prail_act that can be detected before the target rail pressure Prail_tgt is corrected.
  • the injector control unit 81 instructs the energization control to be executed according to the obtained energization time ET.
  • FIG. 5 shows a series of flows for executing the fuel injection control method of the present embodiment. Among these steps, steps S2 and S3 are mainly executed by arithmetic processing by the control device 70.
  • step S1 a preparation process for setting the correction coefficient X for correcting the target rail pressure Prail_tgt in the control device 70 is performed.
  • FIG. 6 shows a specific flowchart of the preparation process.
  • step S11 is performed in the manufacturing stage of the injector 13, and the nozzle in the energization time corresponding to the full lift region of the needle valve under the condition including the allowable maximum pressure that can be realized in the accumulator fuel injector 50.
  • the hydraulic flow rate Qhydr is measured for each nozzle, and the injectors 13 are classified according to the tolerance of the hydraulic flow rate Qhydr of the mounted nozzle.
  • step S12 basic injection amount map information BaseQmap is created using, for example, the central injector as the reference injector among the injectors 13 classified for each tolerance of the hydraulic flow rate Qhydr.
  • step S13 the pressure accumulation type fuel injection device 50 is configured using the injectors 13 belonging to the same category, and the correction coefficient X is set in the control device 70 according to the tolerance of the actual injector 13 used. This correction coefficient X is also used when obtaining the energization time ET to the injector 13. Further, the control device 70 stores basic injection amount map information BaseQmap created using the reference injector BaseInj. When step S11 to step S13 are completed, the preparation process ends.
  • FIG. 7 shows a specific flowchart of the rail pressure control in step S2. This rail pressure control flow is repeated in a predetermined cycle.
  • FIG. 8 shows a specific flowchart of the control of the injector 13 in step S3. The control flow of the injector 13 is also repeatedly performed in a predetermined injection cycle.
  • the target rail pressure Prail_tgt is calculated based on the engine speed Ne, the target fuel injection amount Qtgt, and the like.
  • the corrected target rail pressure Prail_current is obtained by multiplying the target rail pressure Prail_tgt by a correction coefficient X corresponding to the tolerance of the hydraulic flow rate Qhydr.
  • step S23 after the actual rail pressure Prail_act is detected using the rail pressure sensor 21, in step S24, the flow control valve 8 or pressure is determined based on the difference between the corrected target rail pressure Prail_current and the actual rail pressure Prail_act. After the energization control of the control valve 12 is executed, the process returns to step S21.
  • the rail pressure control described above the rail pressure is adjusted so that the injection rate of the actual injector 13 and the injection rate of the reference injector BaseInj coincide.
  • step S31 the target fuel injection amount Qtgt is calculated based on the operating state of the internal combustion engine 40 such as the engine speed Ne and the accelerator operation amount Acc. Is done.
  • step S32 after the actual rail pressure Prail_act is detected using the rail pressure sensor 21, in step S33, the actual rail pressure Prail_act is multiplied by the reciprocal (1 / X) of the correction coefficient X to obtain the assumed rail pressure.
  • Prail_cal is required.
  • step S34 the energization time ET to the actual injector 13 is obtained from the basic injection amount map information BaseQmap based on the assumed rail pressure Prail_cal obtained in step S33 and the target fuel injection amount Qtgt obtained in step S31. Thereafter, in step S35, the energization control of the actual injector 13 is executed according to the energization time ET, and then the process returns to step S31.
  • the actual rail pressure Prail_act is adjusted according to the injection rate characteristic of the actual machine injector 13, while the actual machine injector 13 is in a state before the rail pressure adjustment.
  • the injection control is executed with the energization time ET substantially the same as the energization time at, and the fuel injection amount Qact by the actual injector 13 approximates the target fuel injection amount Qtgt. According to this method, since the injection time does not change greatly before and after the correction, there is no possibility that exhaust emission will deteriorate.
  • the correction coefficient X for correcting the target rail pressure Prail_tgt is obtained based on the hydraulic flow rate Qhydr of the nozzle, but the correction coefficient X is obtained based on the injection rate of the injector 13. It may be what was made. That is, at the stage of manufacturing the injectors 13, the injection rates of the individual injectors 13 actually manufactured are directly measured and classified for each injector 13 having an injection rate characteristic that approximates, and the injection rate of the reference injector and the injection rate of the actual injector The correction coefficient may be obtained by converting the ratio to the pressure.
  • the influence of the variation in the fuel injection amount due to the hydraulic flow rate Qhydr of the nozzle is affected. Since it is small, the correction of the target rail pressure Prail_tgt described so far may be executed only when the energization time is in the second period. By limiting the scenes where correction is performed in this way, it is possible to reduce the load of calculation processing by the control device 70.
  • the injection rate characteristic of the actual injector 13 is learned by a conventionally known method, and the correction coefficient X is updated by the learned injection rate characteristic. If the apparatus 70 is configured, the fuel injection amount can be controlled to the target fuel injection amount in response to a change in the injection rate characteristic due to deterioration with time. Such an aspect is also included in the present invention.
  • the correction unit 79 of the control device 70 of the present embodiment is configured to adjust the actual rail pressure Prail_act by multiplying the target rail pressure Prail_tgt by the correction coefficient X, but the correction target is rail pressure control. Even with the control amount of the flow control valve 8 or the pressure control valve 12 obtained by the unit 77, the fuel injection amount Qact can be similarly controlled to the target fuel injection amount Qtgt. Further, a specific calculation processing method for correction is not limited to multiplication, and a method by addition / subtraction or gradual calculation may be used.
  • the pressure-accumulation fuel injection device is basically the same as the pressure-accumulation fuel injection device of the first embodiment except that the configuration of the rail pressure control unit of the control device is different. It is configured.
  • the pressure accumulation type fuel injection device of the present embodiment will be described focusing on the configuration of the rail pressure control unit.
  • the storage means of the control device includes a plurality of injection amount map information corresponding to the injection rate characteristics of the injector, in addition to the basic injection amount map information created using the reference injector. It is remembered. This injection amount map information is created, for example, according to the injection rate characteristic of the injector classified at the injector manufacturing stage.
  • the control device stores information on the injection rate characteristics of the actual injector used when assembling the accumulator fuel injection device. For example, a correction coefficient X for correcting the target rail pressure Prail_tgt may be used as the injection rate characteristic information.
  • the rail pressure control unit uses the injection amount map information Qmap corresponding to the injection rate characteristics of the actual injector, the target fuel injection amount Qtgt calculated by the target fuel injection amount calculating means, the rail The energization time ET is obtained based on the actual rail pressure Prail_act detected by the pressure detecting means, and energization control for the actual injector is executed.
  • a series of flow for executing the fuel injection control method by the control device of the present embodiment is the same as the flowchart of FIG. 5, but the specific flow of the preparation process of step S1 and the control of the injector 13 of step S3 is as follows. Different from the first embodiment. On the other hand, the rail pressure control in step S2 is executed along the flowchart of FIG.
  • FIG. 9 shows a specific flowchart of a preparation process for executing the fuel injection control method of the present embodiment.
  • step S41 is performed at the stage of manufacturing the injector, and the nozzle hydraulic pressure during the energization time corresponding to the full lift region of the needle valve under conditions including the maximum allowable pressure that can be realized in the accumulator fuel injection device.
  • the flow rate Qhydr is measured for each nozzle, and the injectors are classified according to the tolerance of the hydraulic flow rate Qhydr of the nozzles to be mounted.
  • step S42 a plurality of injection amount map information Qmap corresponding to each injector classified for each tolerance of the hydraulic flow rate Qhydr is created.
  • step S43 an accumulator fuel injection device is configured using injectors belonging to the same category, and a correction coefficient X is set in the control device in accordance with the tolerance of the actual injector used. Further, the control device stores a plurality of injection amount map information Qmap created for each injector classification.
  • step S51 the target fuel injection amount Qtgt_tgt is calculated based on the operating state of the internal combustion engine such as the engine speed Ne and the accelerator operation amount Acc. .
  • step S52 after the actual rail pressure Prail_act is detected using the rail pressure sensor, the corresponding injection amount map information Qmap is determined in step S53 according to the injection rate characteristic of the actual injector defined by the correction coefficient X. Is selected.
  • step S54 based on the actual rail pressure Prail_act detected in step S52 and the target fuel injection amount Qtgt obtained in step S51, the energization time from the injection amount map information Qmap selected in step S53 to the actual injector. ET is required. Thereafter, in step S55, energization control of the actual injector is executed according to the energization time ET, and then the process returns to step S51.
  • the detected rail pressure Prail_act is used as it is.
  • the energization time ET of the actual injector can be obtained.
  • the actual rail pressure Prail_act is adjusted in accordance with the injection rate characteristics of the actual machine injector, while the actual machine injector performs injection control with an energization time ET that is substantially the same as the energization time before the rail pressure adjustment.
  • the fuel injection amount Qact by the actual injector is approximated to the target fuel injection amount Qtgt. Therefore, there is no possibility that the exhaust emission will deteriorate, and the management of the manufacturing tolerance of the nozzle of the injector can be made relatively gradual, and the manufacturing efficiency of the injector can be improved.
  • the correction coefficient X for correcting the target rail pressure Prail_tgt may be obtained based on the injection rate of the injector. Further, the target to be directly corrected may not be the target rail pressure Prail_tgt but the control amount of the flow control valve 8 or the pressure control valve 12. Furthermore, the correction of the target rail pressure Prail_tgt may be executed only when the energization time is in the second period.
  • step S53 described above is omitted.
  • a mode in which the fuel injection amount is controlled to the target fuel injection amount corresponding to the change in the injection rate characteristic due to the deterioration of the injector with time is also included in the present invention.
  • the accumulator fuel injection apparatus is configured to correct the energization time ET together with the correction of the target rail pressure Prail_tgt, and to control the fuel injection amount Qact to the target fuel injection amount Qtgt. It has been done. Although the variation in the injection rate characteristic can be eliminated by correcting the target rail pressure Prail_tgt, the variation in the injection amount may remain due to factors other than the injection rate characteristic.
  • the pressure-accumulation fuel injection device according to the present embodiment is configured to be able to eliminate not only variations in injection rate characteristics, but also variations in injection amounts due to other factors.
  • the method for correcting the energization time ET can be executed by various methods including a conventionally known method.
  • a conventionally known method an example of the configuration of the control device constituting the pressure accumulation type fuel injection device of the present embodiment will be described.
  • FIG. 11 is a block diagram functionally showing a part related to the fuel injection amount correction control in the configuration of the control device of the present embodiment.
  • This control device is configured around a microcomputer having a known configuration, and includes a target injection amount calculation unit 101, a target injection amount correction unit 102, a target rail pressure calculation unit 103, and a rail pressure detection unit 105.
  • the rail pressure control unit 107, the target rail pressure correction unit 109, and the injector control unit 111 are provided. Specifically, each of these units is realized by executing a program by a microcomputer.
  • the control device is provided with a storage unit as in the configuration of the control device 70 of the first embodiment or the second embodiment.
  • the target injection amount calculation unit 101, the target rail pressure calculation unit 103, the rail pressure detection unit 105, the rail pressure control unit 107, the target rail pressure correction unit 109, and the injector control unit 111 are the same as those in the first embodiment or It is comprised similarly to each part which comprises the control apparatus of 2nd Embodiment.
  • correction amount map information ⁇ Qmap for correcting the target fuel injection amount Qtgt is stored in the storage means.
  • the correction amount map information ⁇ Qmap is created based on the difference information between the fuel injection amount by the reference injector BaseInj and the fuel injection amount by the actual injector, and at a plurality of injection points with different rail pressures or target fuel injection amounts.
  • a correction amount ⁇ Q is set. It does not matter whether the correction amount map information ⁇ Qmap is created and stored in advance or is created by arithmetic processing in the control device at the time of initialization of the control device or the like.
  • the target injection amount correction unit 102 is configured to correct the target fuel injection amount Qtgt calculated by the target injection amount calculation unit 101 using the correction amount map information ⁇ Qmap and calculate a corrected target fuel injection amount Qtgt_current. Yes.
  • the actual machine injectors are constituted by the injectors belonging to the same classification of the injection rate characteristics, basically all the actual machines are used by using one correction amount map information ⁇ Qmap.
  • a correction amount ⁇ Q of the target fuel injection amount Qtgt in the injector can be obtained.
  • the target injection amount correction unit 102 calculates a correction amount ⁇ Q corresponding to the assumed rail pressure Prail_cal and the target fuel injection amount Qtgt based on the correction amount map information ⁇ Qmap. For example, out of the correction amount ⁇ Q set in the correction amount map information ⁇ Qmap, the correction amount ⁇ Q used for the correction from the assumed rail pressure Prail_cal calculated by the control device and the correction amount ⁇ Q of the injection point close to the target fuel injection amount Qtgt. Is calculated. Then, the target injection amount correction unit 102 calculates the corrected target fuel injection amount Qtgt_current by adding the calculated correction amount ⁇ Q to the target fuel injection amount Qtgt.
  • the injector control unit 111 calculates the energization time ET to the actual injector based on the calculated corrected target fuel injection amount Qtgt_current and the assumed rail pressure Prail_cal, and executes the energization control of the injector. As shown in FIG. 12, the correction of the target fuel injection amount Qtgt appears in the change in the energization time ET. However, since the rail pressure is controlled so that the injection rate characteristics match, the energization time ET is small. As a result of the adjustment, the injection time of the actual injector coincides with the injection time of the reference injector BaseInj.
  • the pressure accumulation type fuel injection device of the present embodiment by adjusting the rail pressure, not only the injection rate characteristic of the actual injector can be matched to the injection rate characteristic of the reference injector BaseInj, but also by fine adjustment of the energization time ET, The injection time of the injector matches the injection time of the reference injector BaseInj. Therefore, even if the fuel injection amount Qact by the actual injector is made closer to the target fuel injection amount Qtgt, and there is an error in the elements other than the injection rate characteristics between the actual injector and the reference injector BaseInj, the fuel injection control is performed with high accuracy. Will be executed.

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  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

Provided are a fuel injection control device and a pressure accumulation type fuel injection device such that an actual fuel injection amount is controlled to a target fuel injection amount without extending the injection time to an amount not less than the injection time based on a base injector. The fuel injection control device is equipped with a target injection amount computing means for computing the target fuel injection amount; a target rail pressure computing means for computing a target pressure in a common rail; a rail pressure detection means for detecting the pressure in the common rail; a rail pressure control means for controlling the pressure in the common rail; a memory means for storing basic injection amount map information prepared using the base injector; a correction means for correcting the target pressure or the control amount by the rail pressure control means, on the basis of the difference between the injection rate characteristics of the base injector and the injection rate characteristics of the injector; and an injector control means for obtaining energization time on the basis of the basic injection amount map information, and executing injector drive control.

Description

燃料噴射制御装置及び蓄圧式燃料噴射装置Fuel injection control device and accumulator fuel injection device
　本発明は、内燃機関の気筒への燃料噴射制御を実施するための燃料噴射制御装置及び蓄圧式燃料噴射装置に関するものである。特に、実際の燃料噴射量を算出された目標燃料噴射量に制御する燃料噴射制御装置及び蓄圧式燃料噴射装置に関するものである。 The present invention relates to a fuel injection control device and a pressure accumulation fuel injection device for performing fuel injection control to a cylinder of an internal combustion engine. In particular, the present invention relates to a fuel injection control device and an accumulator fuel injection device that control an actual fuel injection amount to a calculated target fuel injection amount.
　従来、内燃機関の気筒内へ燃料を噴射する燃料噴射装置として、高圧ポンプによって圧送される燃料を一時的に蓄積するとともに、複数のインジェクタに対して所定圧力に調節された燃料を供給するコモンレールを備えた蓄圧式燃料噴射装置が用いられている。この蓄圧式燃料噴射装置において、インジェクタは、制御装置による通電制御によって噴射孔が開かれることで燃料の噴射が行われるように構成されている。このインジェクタへの通電時間は、インジェクタに供給される燃料の圧力と目標燃料噴射量とに基づいて基本噴射量マップ情報から求められる。 Conventionally, as a fuel injection device that injects fuel into a cylinder of an internal combustion engine, a common rail that temporarily accumulates fuel pumped by a high-pressure pump and supplies fuel adjusted to a predetermined pressure to a plurality of injectors The pressure accumulation type fuel injection device provided is used. In this pressure accumulation type fuel injection device, the injector is configured such that fuel is injected by opening an injection hole by energization control by a control device. The energization time for the injector is obtained from the basic injection amount map information based on the pressure of the fuel supplied to the injector and the target fuel injection amount.
　具体的に、目標燃料噴射量は、例えば、内燃機関の回転数（以下「機関回転数」と称する。）とアクセル操作量とに基づいて演算によって求められる。また、インジェクタへの通電時間は、コモンレール内の圧力（以下「レール圧」と称する。）と通電時間と燃料噴射量との関係を示す基本噴射量マップ情報を用いて、圧力センサ等によって検出されるコモンレール内の圧力（以下「実レール圧」と称する。）と目標燃料噴射量とに基づいて決定される。 Specifically, the target fuel injection amount is obtained by calculation based on, for example, the rotation speed of the internal combustion engine (hereinafter referred to as “engine rotation speed”) and the accelerator operation amount. The energization time to the injector is detected by a pressure sensor or the like using basic injection amount map information indicating the relationship between the pressure in the common rail (hereinafter referred to as “rail pressure”), the energization time, and the fuel injection amount. Determined based on the pressure in the common rail (hereinafter referred to as "actual rail pressure") and the target fuel injection amount.
　燃料噴射装置においては、気筒に噴射される燃料噴射量が目標燃料噴射量に対して過不足を生じると、排気エミッションや運転性の悪化等を招くおそれがあるため、理想的には目標燃料噴射量に対して過不足なく燃料噴射が行われることが望まれる。 In a fuel injection device, if the fuel injection amount injected into the cylinder is excessive or insufficient with respect to the target fuel injection amount, there is a risk of causing exhaust emission, deterioration of operability, etc. It is desired that fuel injection be performed without excess or deficiency with respect to the amount.
　ここで、インジェクタの生産が大量生産によって行われる場合、加工精度のばらつき等によってそれぞれのインジェクタの通電時間と燃料噴射量との関係（以下、この関係を「噴射特性」と称する。）に公差が生じることは避けられない。そのため、インジェクタの噴射特性に応じて燃料噴射の補正値を設定するように構成した燃料噴射制御装置が提案されている。より具体的には、学習条件成立時に、単発的に燃料噴射を行い、噴射後の内燃機関の状態変化量から実燃料噴射量を検出する学習動作を、燃料噴射弁の通電時間を変更しつつ複数回実行し、その検出結果から、燃料噴射弁の噴射特性を推定して燃料噴射量を目標燃料噴射量に制御するための通電時間補正値を算出するようにした燃料噴射制御装置が開示されている（例えば、特許文献１を参照。）。 Here, when the production of injectors is performed by mass production, there is a tolerance in the relationship between the energization time of each injector and the fuel injection amount (hereinafter, this relationship is referred to as “injection characteristics”) due to variations in machining accuracy. It cannot be avoided. Therefore, there has been proposed a fuel injection control device configured to set a correction value for fuel injection according to the injection characteristics of the injector. More specifically, when the learning condition is satisfied, a learning operation is performed in which fuel injection is performed once and the actual fuel injection amount is detected from the state change amount of the internal combustion engine after the injection, while the energization time of the fuel injection valve is changed. Disclosed is a fuel injection control apparatus that is executed a plurality of times and that calculates the energization time correction value for controlling the fuel injection amount to the target fuel injection amount by estimating the injection characteristics of the fuel injection valve from the detection result. (For example, refer to Patent Document 1).
特開２００９－５７９１１号公報　（全文、全図）JP 2009-57911 A (full text, full diagram)
　上記特許文献１に記載の燃料噴射制御装置は、通電時間を補正することによって燃料噴射量を制御するものである。インジェクタのノズルを通過する燃料の流量が、目標燃料噴射量を求める際の基準となる基準インジェクタと一致しているのであれば、特許文献１に記載の制御方法にしたがって通電時間を補正することによって、噴射期間中のある時点でのインジェクタの噴射流量（以下、この噴射流量を「インジェクタの噴射率」と称する。）の波形を、基準インジェクタによって目標燃料噴射量分の噴射を実行したときの波形に一致させることができる。 The fuel injection control device described in Patent Document 1 controls the fuel injection amount by correcting the energization time. If the flow rate of the fuel that passes through the nozzle of the injector matches the reference injector that is the reference for obtaining the target fuel injection amount, the energization time is corrected according to the control method described in Patent Document 1. The waveform of the injection flow rate of the injector at a certain point in the injection period (hereinafter, this injection flow rate is referred to as the “injection rate of the injector”) is the waveform when the target fuel injection amount is injected by the reference injector. Can match.
　しかしながら、現実的には、ノズルの加工精度のばらつきによってインジェクタごとにノズルの通過流量にばらつきがあり、インジェクタの単位時間当たりの燃料噴射量の特性（以下、「噴射率特性」と称する。）が異なっていることが多い。通電時間を補正することによって燃料噴射量を目標燃料噴射量に制御しようとした場合、インジェクタの噴射率特性と基準インジェクタの噴射率特性とが異なると、燃料噴射量を目標燃料噴射量に制御することはできても、噴射時間が基準インジェクタによる噴射時間とは異なることになる。 However, in reality, there is a variation in the flow rate of the nozzle for each injector due to variations in the processing accuracy of the nozzle, and the fuel injection amount characteristic per unit time of the injector (hereinafter referred to as “injection rate characteristic”). Often different. When the fuel injection amount is controlled to the target fuel injection amount by correcting the energization time, the fuel injection amount is controlled to the target fuel injection amount if the injection rate characteristic of the injector is different from the injection rate characteristic of the reference injector. Even if it can, the injection time will be different from the injection time by the reference injector.
　図１３は、インジェクタによる燃料噴射を実行した場合における電流波形と噴射率波形とを示している。図１３中、所定の基準圧力下においてノズルを通過する燃料の流量（以下、この流量を「ノズルの油圧流量」と称する。）が公差の下限値を示すインジェクタ（以下「下限品」と称する。）の噴射率波形が一点鎖線で示され、ノズルの油圧流量が公差の上限値を示すインジェクタ（以下「上限品」と称する。）の噴射率波形が点線で示され、ノズルの油圧流量が公差の中央値を示すインジェクタ（以下「中央品」と称する。）の噴射率波形が実線で示されている。 FIG. 13 shows a current waveform and an injection rate waveform when fuel injection by the injector is executed. In FIG. 13, an injector (hereinafter referred to as “lower limit product”) in which the flow rate of fuel passing through the nozzle under a predetermined reference pressure (hereinafter referred to as “nozzle hydraulic flow rate”) indicates a lower limit value of tolerance. ) Injection rate waveform is indicated by a one-dot chain line, the injection rate waveform of an injector (hereinafter referred to as “upper limit product”) in which the nozzle hydraulic flow rate indicates the upper limit of tolerance is indicated by a dotted line, and the nozzle hydraulic flow rate is tolerance The injection rate waveform of an injector (hereinafter referred to as “central product”) indicating the median value of is indicated by a solid line.
　インジェクタによる燃料噴射は、インジェクタへの通電開始からしばらく遅れて開始するとともに、通電の停止からしばらく遅れて終了する。燃料噴射の開始時点から終了時点までの噴射率を積分した値が燃料噴射量に相当する。この図１３に示すように、噴射期間中のある時点での噴射率はノズルの油圧流量が小さいほど低くなり、同じ電流波形で通電した場合であっても、ノズルの油圧流量が小さいインジェクタほど燃料噴射量は少なくなる。 The fuel injection by the injector starts after a while from the start of energization to the injector and ends after a while after the energization stops. A value obtained by integrating the injection rate from the start point to the end point of fuel injection corresponds to the fuel injection amount. As shown in FIG. 13, the injection rate at a certain point in the injection period becomes lower as the hydraulic flow rate of the nozzle is smaller, and even when the same current waveform is applied, the smaller the injector, the lower the hydraulic flow rate of the nozzle. The injection amount is reduced.
　この燃料噴射量のばらつきを、通電時間のみを調節することによって中央品に合わせようとすると、図１４に示すように、下限品及び上限品の噴射終了時点がそれぞれ中央品の噴射終了時点をまたいで補正されることになり、下限品の噴射時間は中央品よりも延びることになる。噴射時間が基準インジェクタによる噴射時間よりも延びてしまうことは、内燃機関において排気エミッションを悪化させることにつながるおそれがある。 If the variation in the fuel injection amount is adjusted to the central product by adjusting only the energization time, as shown in FIG. 14, the injection end time of the lower limit product and the upper limit product cross over the injection end time of the central product, respectively. Thus, the injection time of the lower limit product is longer than that of the central product. If the injection time is longer than the injection time by the reference injector, there is a possibility that exhaust emission is deteriorated in the internal combustion engine.
　そこで、本発明の発明者は鋭意努力し、燃料噴射量を補正するにあたり、インジェクタの噴射率特性が基準インジェクタの噴射率特性に近似するようにレール圧を調節することによりこのような問題を解決できることを見出し、本発明を完成させたものである。すなわち、本発明は、噴射時間を基準インジェクタによる噴射時間以上に延ばすことなく実燃料噴射量を目標燃料噴射量に制御することができる燃料噴射制御装置及び蓄圧式燃料噴射装置を提供することを目的とする。 Therefore, the inventors of the present invention have made diligent efforts to correct the fuel injection amount by solving the problem by adjusting the rail pressure so that the injection rate characteristic of the injector approximates the injection rate characteristic of the reference injector. The present invention has been found and completed. That is, the present invention aims to provide a fuel injection control device and an accumulator fuel injection device that can control the actual fuel injection amount to the target fuel injection amount without extending the injection time beyond the injection time by the reference injector. And
　本発明によれば、複数のインジェクタが接続されたコモンレールを備えた蓄圧式燃料噴射装置による内燃機関への燃料噴射制御を行う燃料噴射制御装置において、内燃機関の運転状態に基づいて目標燃料噴射量を算出する目標噴射量演算手段と、内燃機関の運転状態に基づいてコモンレール内の目標圧力を算出する目標レール圧演算手段と、コモンレール内の圧力を検出するレール圧検出手段と、コモンレール内の圧力を制御するレール圧制御手段と、基準インジェクタを用いて作成された、コモンレール内の圧力と通電時間と燃料噴射量との関係を示す基本噴射量マップ情報が記憶された記憶手段と、基準インジェクタの噴射率特性とインジェクタの噴射率特性との差に基づいて目標圧力又はレール圧制御手段の制御量を補正する補正手段と、基本噴射量マップ情報に基づいて通電時間を求めてインジェクタの駆動制御を実行するインジェクタ制御手段と、を備えることを特徴とする燃料噴射制御装置が提供され、上述した問題を解決することができる。 According to the present invention, in a fuel injection control device that performs fuel injection control to an internal combustion engine by an accumulator fuel injection device having a common rail to which a plurality of injectors are connected, the target fuel injection amount is based on the operating state of the internal combustion engine. Target injection amount calculating means for calculating the target pressure, target rail pressure calculating means for calculating the target pressure in the common rail based on the operating state of the internal combustion engine, rail pressure detecting means for detecting the pressure in the common rail, and pressure in the common rail Rail pressure control means for controlling the fuel, storage means for storing basic injection amount map information indicating the relationship between the pressure in the common rail, the energization time, and the fuel injection amount, which is created using the reference injector, and the reference injector Correction method for correcting the control amount of the target pressure or rail pressure control means based on the difference between the injection rate characteristic and the injection rate characteristic of the injector And an injector control means for determining the energization time based on the basic injection amount map information and executing drive control of the injector. it can.
　また、本発明の燃料噴射制御装置を構成するにあたり、補正手段が、基準インジェクタの噴射率のピークとインジェクタの噴射率のピークとが一致するように目標圧力又はレール圧制御手段の制御量を補正することが好ましい。 In configuring the fuel injection control device of the present invention, the correction means corrects the control amount of the target pressure or the rail pressure control means so that the peak of the injection rate of the reference injector matches the peak of the injection rate of the injector. It is preferable to do.
　また、本発明の燃料噴射制御装置を構成するにあたり、補正手段が、所定圧力下における基準インジェクタのノズルの通過流量とインジェクタのノズルの通過流量との比率を変換して得られる圧力比の値に基づいて、目標圧力又はレール圧制御手段の制御量の補正量を求めることが好ましい。 Further, in configuring the fuel injection control device of the present invention, the correcting means converts the ratio of the flow rate of the reference injector nozzle and the flow rate of the injector nozzle under a predetermined pressure into a pressure ratio value obtained by converting the ratio. Based on this, it is preferable to obtain the correction amount of the control amount of the target pressure or rail pressure control means.
　また、本発明の燃料噴射制御装置を構成するにあたり、所定圧力が、蓄圧式燃料噴射装置において実現され得るコモンレールの許容最大圧力であることが好ましい。 In configuring the fuel injection control device of the present invention, it is preferable that the predetermined pressure is an allowable maximum pressure of the common rail that can be realized in the accumulator fuel injection device.
　また、本発明の燃料噴射制御装置を構成するにあたり、所定圧力下における基準インジェクタの噴射率及びインジェクタの噴射率に基づいて、インジェクタの噴射率を基準インジェクタの噴射率に一致させるための補正係数があらかじめ求められ、補正手段が、補正係数を用いて目標圧力又はレール圧制御手段の制御量を補正することが好ましい。 Further, in configuring the fuel injection control device of the present invention, a correction coefficient for making the injection rate of the injector coincide with the injection rate of the reference injector based on the injection rate of the reference injector and the injection rate of the injector under a predetermined pressure. It is preferable that the correction means is obtained in advance and the correction means corrects the control amount of the target pressure or the rail pressure control means using the correction coefficient.
　また、本発明の燃料噴射制御装置を構成するにあたり、インジェクタの噴射率又はノズルの通過流量が、インジェクタの製造段階において個々のインジェクタごとにあらかじめ求められたものであることが好ましい。 Further, in configuring the fuel injection control device of the present invention, it is preferable that the injection rate of the injector or the passage flow rate of the nozzle is obtained in advance for each individual injector in the manufacturing stage of the injector.
　また、本発明の燃料噴射制御装置を構成するにあたり、インジェクタは、ノズルの座面に対して離接可能なニードル弁を離座させることによって燃料噴射が行われるものであり、インジェクタの通電時間は、インジェクタの噴射流量がニードル弁のリフト量に支配される第１の期間と、インジェクタの噴射流量が噴孔面積に支配される第２の期間と、からなり、インジェクタの通電時間が第２の期間である場合に、補正手段が目標圧力又はレール圧制御手段の制御量の補正を実行することが好ましい。 Further, in configuring the fuel injection control device of the present invention, the injector performs fuel injection by separating a needle valve that can be separated from and brought into contact with the seat surface of the nozzle. , A first period in which the injection flow rate of the injector is governed by the lift amount of the needle valve, and a second period in which the injection flow rate of the injector is governed by the nozzle hole area. In the case of the period, it is preferable that the correction unit corrects the control amount of the target pressure or the rail pressure control unit.
　また、本発明の燃料噴射制御装置を構成するにあたり、目標噴射量演算手段又はインジェクタ制御手段が、基準インジェクタによる基準燃料噴射量とインジェクタによる実燃料噴射量との差分情報に基づいて目標燃料噴射量又はインジェクタ制御手段の制御量の補正を実行することが好ましい。 Further, in configuring the fuel injection control device of the present invention, the target injection amount calculation means or the injector control means is configured so that the target fuel injection amount is based on the difference information between the reference fuel injection amount by the reference injector and the actual fuel injection amount by the injector. Alternatively, it is preferable to correct the control amount of the injector control means.
　また、本発明の燃料噴射制御装置を構成するにあたり、インジェクタ制御手段が、レール圧検出手段によって検出されたコモンレール内の圧力に基づいて得られる、補正を行わなかった場合の想定レール圧を用いて通電時間を求めることが好ましい。 Further, in configuring the fuel injection control device of the present invention, the injector control means uses the assumed rail pressure when correction is not performed, which is obtained based on the pressure in the common rail detected by the rail pressure detection means. It is preferable to obtain the energization time.
　また、本発明の燃料噴射制御装置を構成するにあたり、記憶手段には、基本噴射量マップ情報以外に、噴射率特性に応じた複数の噴射量マップ情報が記憶され、インジェクタ制御手段が、インジェクタの噴射率特性に対応する噴射量マップ情報を選択して通電時間を求めることが好ましい。 Further, when configuring the fuel injection control device of the present invention, the storage means stores a plurality of injection quantity map information corresponding to the injection rate characteristics in addition to the basic injection quantity map information, and the injector control means It is preferable to select the injection amount map information corresponding to the injection rate characteristic to obtain the energization time.
　また、本発明の別の態様は、燃料を加圧して圧送する高圧ポンプと、高圧ポンプによって圧送される燃料を蓄積するコモンレールと、コモンレールに接続された複数のインジェクタと、を備えるとともに、上述したいずれかの燃料噴射制御装置を備えることを特徴とする蓄圧式燃料噴射装置である。 Another aspect of the present invention includes a high-pressure pump that pressurizes and pumps fuel, a common rail that accumulates fuel pumped by the high-pressure pump, and a plurality of injectors connected to the common rail. An accumulator fuel injection device comprising any one of the fuel injection control devices.
　また、本発明の蓄圧式燃料噴射装置を構成するにあたり、複数のインジェクタとして、それぞれ噴射率特性が近似するインジェクタを備えることが好ましい。 In constructing the pressure accumulation type fuel injection device of the present invention, it is preferable to provide injectors having similar injection rate characteristics as the plurality of injectors.
　本発明の燃料噴射制御装置及び蓄圧式燃料噴射装置によれば、インジェクタの噴射率特性が基準インジェクタの噴射率特性と近似するようにレール圧の調節が行われ、内燃機関に搭載されたインジェクタの噴射率と、基本噴射量マップ情報の作成に用いられた基準インジェクタの噴射率とのばらつきの影響が低減される。そのため、噴射時間をできる限り変えないようにして、燃料噴射量を目標燃料噴射量に制御することができる。したがって、排気エミッションの悪化を抑えた燃料噴射量の補正が実行されるようになる。
　また、このような燃料噴射量の補正が可能になれば、インジェクタの製造段階において、ノズルの油圧流量の製造公差を広げることができ、インジェクタの製造効率の向上が図られる。 According to the fuel injection control device and the accumulator fuel injection device of the present invention, the rail pressure is adjusted so that the injection rate characteristic of the injector approximates the injection rate characteristic of the reference injector, and the injector mounted on the internal combustion engine The influence of variation between the injection rate and the injection rate of the reference injector used for creating the basic injection amount map information is reduced. Therefore, the fuel injection amount can be controlled to the target fuel injection amount while changing the injection time as much as possible. Therefore, the correction of the fuel injection amount that suppresses the deterioration of the exhaust emission is executed.
Further, if such correction of the fuel injection amount becomes possible, the manufacturing tolerance of the nozzle hydraulic flow rate can be widened in the injector manufacturing stage, and the manufacturing efficiency of the injector can be improved.
蓄圧式燃料噴射装置の構成の一例について説明するための図である。It is a figure for demonstrating an example of a structure of a pressure accumulation type fuel-injection apparatus. インジェクタの通電時間と燃料噴射量との関係を示す図である。It is a figure which shows the relationship between the energization time of an injector, and fuel injection quantity. 第１の実施の形態の蓄圧式燃料噴射装置に備えられた制御装置の構成例を示すブロック図である。It is a block diagram which shows the structural example of the control apparatus with which the pressure accumulation type fuel injection apparatus of 1st Embodiment was equipped. 補正による噴射率波形の変化について説明するための図である。It is a figure for demonstrating the change of the injection rate waveform by correction | amendment. 燃料噴射量の補正方法の全体的な流れを示すフローチャートである。It is a flowchart which shows the whole flow of the correction method of fuel injection quantity. 第１の実施の形態にかかる準備工程について説明するためのフローチャートである。It is a flowchart for demonstrating the preparatory process concerning 1st Embodiment. 第１の実施の形態にかかるレール圧制御方法について説明するためのフローチャートである。It is a flowchart for demonstrating the rail pressure control method concerning 1st Embodiment. 第１の実施の形態にかかるインジェクタの制御方法について説明するためのフローチャートである。It is a flowchart for demonstrating the control method of the injector concerning 1st Embodiment. 第２の実施の形態にかかる準備工程について説明するためのフローチャートである。It is a flowchart for demonstrating the preparatory process concerning 2nd Embodiment. 第２の実施の形態にかかるインジェクタの制御方法について説明するためのフローチャートである。It is a flowchart for demonstrating the control method of the injector concerning 2nd Embodiment. 第３の実施の形態の蓄圧式燃料噴射装置に備えられた制御装置の構成例を示すブロック図である。It is a block diagram which shows the structural example of the control apparatus with which the pressure accumulation type fuel injection apparatus of 3rd Embodiment was equipped. 第３の実施の形態の噴射量補正について説明するための図である。It is a figure for demonstrating the injection quantity correction | amendment of 3rd Embodiment. 噴射率特性が異なるインジェクタそれぞれの噴射率波形について説明するための図である。It is a figure for demonstrating the injection rate waveform of each injector from which an injection rate characteristic differs. 従来の補正による噴射率波形の変化について説明するための図である。It is a figure for demonstrating the change of the injection rate waveform by the conventional correction | amendment.
　以下、図面を参照して、本発明の燃料噴射制御装置及び蓄圧式燃料噴射装置に関する実施の形態について具体的に説明する。ただし、以下の実施の形態は、本発明の一態様を示すものであり、本発明を限定するものではなく本発明の範囲内で任意に変更することが可能である。なお、それぞれの図中、同じ符号を付してあるものは同一の部材を示しており、適宜説明が省略されている。 Hereinafter, embodiments of the fuel injection control device and the accumulator fuel injection device according to the present invention will be specifically described with reference to the drawings. However, the following 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.
［第１の実施の形態］
１．蓄圧式燃料噴射装置
　図１は、本発明の第１の実施の形態にかかる蓄圧式燃料噴射装置５０の構成の一例を示している。この図１に示す蓄圧式燃料噴射装置５０は、内燃機関４０としてのディーゼルエンジンの気筒内に燃料を噴射する蓄圧式燃料噴射装置であって、燃料タンク１と、低圧ポンプ２と、高圧ポンプ５と、コモンレール１０と、インジェクタ１３と、制御装置７０等を主たる構成要素として備えている。この蓄圧式燃料噴射装置５０の基本的な構成は従来公知のものにすぎず、一部が異なる構成となっていても構わない。 [First Embodiment]
1. Accumulated Fuel Injection Device FIG. 1 shows an example of the configuration of an accumulator fuel injection device 50 according to the first embodiment of the present invention. An accumulator fuel injection apparatus 50 shown in FIG. 1 is an accumulator fuel injection apparatus that injects fuel into a cylinder of a diesel engine as an internal combustion engine 40, and includes a fuel tank 1, a low pressure pump 2, and a high pressure pump 5. And common rail 10, injector 13, control device 70, and the like as main components. The basic configuration of the pressure accumulating fuel injection apparatus 50 is merely a conventionally known configuration, and a part of the configuration may be different.
　低圧ポンプ２は、燃料タンク１内の燃料を吸い上げて高圧ポンプ５に対して圧送する。高圧ポンプ５は、低圧ポンプ２によって圧送される燃料を加圧してコモンレール１０に圧送する。高圧ポンプ５の加圧室５ａの上流側には流量制御弁８が備えられ、内燃機関４０の運転状態やレール圧の目標値（以下「目標レール圧」と称する。）に応じて加圧室５ａに流入する燃料の流量を調節可能になっている。また、流量制御弁８よりも上流側にはオーバーフローバルブ１４が接続されており、低圧ポンプ２によって圧送される燃料の圧力が所定の圧力に調節される。 The low pressure pump 2 sucks up the fuel in the fuel tank 1 and pumps it to the high pressure pump 5. The high pressure pump 5 pressurizes the fuel pumped by the low pressure pump 2 and pumps it to the common rail 10. A flow rate control valve 8 is provided on the upstream side of the pressurizing chamber 5a of the high-pressure pump 5, and according to the operating state of the internal combustion engine 40 and a target value of rail pressure (hereinafter referred to as “target rail pressure”). The flow rate of the fuel flowing into 5a can be adjusted. An overflow valve 14 is connected upstream of the flow rate control valve 8, and the pressure of the fuel pumped by the low pressure pump 2 is adjusted to a predetermined pressure.
　コモンレール１０は、高圧ポンプ５から圧送される高圧の燃料を一時的に蓄積し、接続されている複数のインジェクタ（以下、蓄圧式燃料噴射装置５０に用いられているインジェクタを「実機インジェクタ」と称する場合がある。）１３に対して高圧の燃料を供給する。コモンレール１０にはレール圧を検出するためのレール圧センサ２１や圧力制御弁１２が備えられている。圧力制御弁１２は安全弁であってもよいが、本実施形態においては、制御装置７０によって通過流量の制御が行われる電磁制御弁が用いられており、目標レール圧に応じてコモンレール１０内の燃料の排出流量を調節可能になっている。 The common rail 10 temporarily accumulates high-pressure fuel pumped from the high-pressure pump 5, and a plurality of connected injectors (hereinafter, the injectors used in the pressure-accumulation fuel injection device 50 are referred to as “actual injectors”). High pressure fuel is supplied to 13. The common rail 10 is provided with a rail pressure sensor 21 and a pressure control valve 12 for detecting the rail pressure. Although the pressure control valve 12 may be a safety valve, in the present embodiment, an electromagnetic control valve that controls the flow rate of the flow by the control device 70 is used, and the fuel in the common rail 10 according to the target rail pressure. The discharge flow rate is adjustable.
　インジェクタ１３は、噴射孔が設けられたノズルと、ノズルの座面に離接可能なノズルニードルと、ノズルニードルの後端側に作用する背圧を制御することによってノズルニードルの進退移動を制御する背圧制御弁とを備えている。インジェクタ１３には、例えば、背圧制御弁として電磁ソレノイドが用いられる電磁制御型のインジェクタや、背圧制御弁としてピエゾアクチュエータが用いられる電歪型のインジェクタがあり、いずれのインジェクタであっても使用することができる。 The injector 13 controls the advancing and retreating movement of the nozzle needle by controlling the nozzle provided with the injection hole, the nozzle needle that can be separated from and contacting the seat surface of the nozzle, and the back pressure acting on the rear end side of the nozzle needle. And a back pressure control valve. The injector 13 includes, for example, an electromagnetic control type injector in which an electromagnetic solenoid is used as a back pressure control valve, and an electrostriction type injector in which a piezo actuator is used as a back pressure control valve. Any injector can be used. can do.
　このインジェクタ１３は、背圧制御弁への通電時間によってニードル弁のリフト量が変化する構成のものであるが、通電時間が短い第１の期間（シート絞り領域）においては、ニードル弁のリフト量が小さく、ノズルの座面とニードル弁とによって規定される燃料通過面積が噴射孔の合計面積よりも小さくなる。そのため、通電時間の第１の期間においては、インジェクタ１３の噴射流量はニードル弁のリフト量に支配される。 The injector 13 has a configuration in which the lift amount of the needle valve changes depending on the energization time of the back pressure control valve, but in the first period (the seat restricting region) where the energization time is short, the lift amount of the needle valve The fuel passage area defined by the nozzle seating surface and the needle valve is smaller than the total area of the injection holes. Therefore, in the first period of energization time, the injection flow rate of the injector 13 is governed by the lift amount of the needle valve.
　また、通電時間が第１の期間を超える第２の期間においてはニードル弁のリフト量は大きくなり、ノズルの座面とニードル弁とによって規定される燃料通過面積が噴射孔の合計面積よりも大きくなる。そのため、通電時間の第２の期間（噴孔絞り領域）においては、インジェクタ１３の噴射流量は噴射孔の合計面積に支配される。 Further, in the second period in which the energization time exceeds the first period, the lift amount of the needle valve becomes large, and the fuel passage area defined by the seat surface of the nozzle and the needle valve is larger than the total area of the injection holes. Become. Therefore, in the second period of the energization time (injection aperture region), the injection flow rate of the injector 13 is governed by the total area of the injection holes.
　ここで、インジェクタ１３の生産が大量生産によって行われる場合、それぞれの部品の加工精度のばらつきは避けられない。特に、噴射孔を介してノズルを通過する燃料の流量は、同じ圧力の燃料であっても噴射孔のばらつきによって個々のインジェクタ１３ごとにばらつきを生じる。ノズルを通過する燃料の流量はインジェクタ１３の噴射率に影響を与え、特に通電時間の第２の期間（噴孔絞り領域）において燃料噴射量にばらつきを生じさせる要素となる。 Here, when the injector 13 is produced by mass production, variations in the machining accuracy of each part are inevitable. In particular, the flow rate of the fuel passing through the nozzle through the injection hole varies for each injector 13 due to the variation of the injection hole even if the fuel has the same pressure. The flow rate of the fuel that passes through the nozzle affects the injection rate of the injector 13, and becomes a factor that causes variations in the fuel injection amount particularly in the second period (injection aperture restriction region) of the energization time.
　図２は、低圧状態、中圧状態、高圧状態それぞれの圧力下における上限品、中央品、下限品のインジェクタ１３の通電時間ETと燃料噴射量Qactとの関係を示している。
　基本的に、通電時間ETが短い第１の期間（シート絞り領域）においては、噴射孔の形状にばらつきがあっても噴射量に及ぶ影響は小さい。一方、通電時間ETが長くなる第２の期間（噴孔絞り領域）においては、噴射孔の形状のばらつきによって噴射率に差が生じるため、同じ圧力下で、同じ通電時間ETで噴射を実行した場合であっても、上限品、中央品、下限品それぞれのインジェクタ１３の噴射量にばらつきが生じている。 FIG. 2 shows the relationship between the energization time ET and the fuel injection amount Qact of the injectors 13 of the upper limit product, the central product, and the lower limit product under the respective pressures in the low pressure state, the intermediate pressure state, and the high pressure state.
Basically, in the first period (sheet restriction region) where the energization time ET is short, even if the shape of the injection hole varies, the influence on the injection amount is small. On the other hand, in the second period (injection hole constriction region) in which the energization time ET becomes long, a difference occurs in the injection rate due to the variation in the shape of the injection hole. Therefore, the injection was executed with the same energization time ET under the same pressure. Even in this case, the injection amount of the injector 13 for each of the upper limit product, the center product, and the lower limit product varies.
　通常、インジェクタ１３の製造段階においては、所定圧力下においてそれぞれのノズルを通過する燃料の流量（油圧流量）の検査が行われている。インジェクタ１３は、内燃機関４０の各気筒に備えられるものであるが、本実施形態の蓄圧式燃料噴射装置５０において使用されるすべてのインジェクタ１３は、ノズルの油圧流量が近似するもの、すなわち、噴射率特性が近似するものによって構成されている。噴射率特性が近似する複数のインジェクタ１３が用いられていれば、レール圧及び通電時間が同じである限り燃料噴射量が等しくなり、燃料噴射量の補正制御を実行する際に制御装置７０に過度な処理能力を要求することがなくなる。 Usually, at the manufacturing stage of the injector 13, the flow rate of fuel (hydraulic flow rate) passing through each nozzle under a predetermined pressure is inspected. The injector 13 is provided in each cylinder of the internal combustion engine 40. However, all of the injectors 13 used in the accumulator fuel injection device 50 of the present embodiment have an approximation of the nozzle hydraulic flow rate, that is, the injection. The rate characteristic is approximated. If a plurality of injectors 13 having similar injection rate characteristics are used, the fuel injection amount becomes equal as long as the rail pressure and the energization time are the same. No need for high processing power.
２．制御装置
　図３は、本実施形態の制御装置７０の構成のうち燃料噴射量の補正制御に関連する部分について機能的に表したブロック図を示している。
　この制御装置７０は、公知の構成からなるマイクロコンピュータを中心に構成されており、目標噴射量演算部７１と、目標レール圧演算部７３と、レール圧検出部７５と、レール圧制御部７７と、補正部７９と、インジェクタ制御部８１とを備えている。これらの各部は、具体的にはマイクロコンピュータによるプログラムの実行によって実現される。 2. 3. Control Device FIG. 3 is a block diagram functionally showing a part related to fuel injection amount correction control in the configuration of the control device 70 of the present embodiment.
The control device 70 is configured around a microcomputer having a known configuration, and includes a target injection amount calculation unit 71, a target rail pressure calculation unit 73, a rail pressure detection unit 75, and a rail pressure control unit 77. , A correction unit 79 and an injector control unit 81 are provided. Specifically, each of these units is realized by executing a program by a microcomputer.
　また、制御装置７０には、ＲＡＭ（Random Access Memory）等の図示しない記憶手段が備えられており、記憶手段には、種々の情報があらかじめ記憶され、あるいは、他の各部によって読み込まれた情報や演算結果が記憶される。この制御装置７０には、コモンレール１０に備えられたレール圧センサ２１からのレール圧信号が入力されるほか、内燃機関４０に備えられた回転数センサ４４からの機関回転数信号や、アクセルセンサからのアクセル操作量信号をはじめとして、他のセンサからのセンサ信号が入力される。 Further, the control device 70 is provided with storage means (not shown) such as RAM (Random Access Memory), and various information is stored in the storage means in advance, or information read by other units, The calculation result is stored. In addition to the rail pressure signal from the rail pressure sensor 21 provided in the common rail 10 being input to the control device 70, the engine speed signal from the rotation speed sensor 44 provided in the internal combustion engine 40, and the accelerator sensor In addition to the accelerator operation amount signal, sensor signals from other sensors are input.
　目標噴射量演算部７１は、機関回転数Ne及びアクセル操作量Accを読み込み、目標燃料噴射量Qtgtを算出できるように構成されている。また、目標レール圧演算部７３は、算出された目標燃料噴射量Qtgt及び機関回転数Neに基づいて目標レール圧Prail_tgtを算出できるように構成されている。また、レール圧検出部７５は、レール圧センサ２１からのレール圧信号を読み込み、実レール圧Prail_actを検出できるように構成されている。 The target injection amount calculation unit 71 is configured to read the engine speed Ne and the accelerator operation amount Acc and calculate the target fuel injection amount Qtgt. The target rail pressure calculation unit 73 is configured to calculate the target rail pressure Prail_tgt based on the calculated target fuel injection amount Qtgt and the engine speed Ne. The rail pressure detection unit 75 is configured to read a rail pressure signal from the rail pressure sensor 21 and detect the actual rail pressure Prail_act.
　補正部７９は、記憶手段に記憶された基本噴射量マップ情報BaseQmapの基準とされた基準インジェクタBaseInjの噴射率特性と、実機インジェクタ１３の噴射率特性との差に基づいて、目標レール圧演算手段７３で求められた目標レール圧Prail_tgtを補正し、補正後目標レール圧Prail_currentを求めるように構成されている。目標レール圧Prail_tgtの補正は、例えば、噴射期間中における実機インジェクタ１３の噴射率のピークを基準インジェクタBaseInjの噴射率のピークに一致させるように行われる。 The correction unit 79 is configured to calculate the target rail pressure based on the difference between the injection rate characteristic of the reference injector BaseInj used as the reference of the basic injection amount map information BaseQmap stored in the storage unit and the injection rate characteristic of the actual injector 13. The target rail pressure Prail_tgt obtained at 73 is corrected, and the corrected target rail pressure Prail_current is obtained. The target rail pressure Prail_tgt is corrected, for example, so that the peak of the injection rate of the actual injector 13 during the injection period coincides with the peak of the injection rate of the reference injector BaseInj.
　本発明の基本的な考え方を説明すると以下のようになる。
　インジェクタの噴射率のピーク値はノズルの油圧流量Qhydrによって規定され、この油圧流量Qhydrは、圧力Pの平方根の定数α倍になる（下記式（１））。
　Qhydr = α×√P　…（１） The basic concept of the present invention will be described as follows.
The peak value of the injection rate of the injector is defined by the hydraulic flow rate Qhydr of the nozzle, and this hydraulic flow rate Qhydr is a constant α times the square root of the pressure P (the following formula (1)).
Qhydr = α × √P (1)
　圧力Pは、ノズルのシート側の圧力と噴射孔出口側の圧力との差に相当し、すべてのノズルの油圧流量Qhydrを同条件で算出する場合においては圧力Pは一定となるため、油圧流量Qhydrのばらつきは定数αのばらつきによるものと考えられる。この定数αのばらつきは、噴射孔の入口径と出口径、噴射孔入口側の曲率半径と出口側の曲率半径、噴射孔を通過する燃料の流量係数等に代表される、ノズルの出来栄え要素のばらつきを内包している。 The pressure P corresponds to the difference between the pressure on the nozzle seat side and the pressure on the injection hole outlet side. When calculating the hydraulic flow rate Qhydr for all nozzles under the same conditions, the pressure P is constant. The variation of Qhydr is considered to be due to the variation of the constant α. This variation in the constant α is caused by nozzle performance factors represented by the inlet diameter and outlet diameter of the injection hole, the curvature radius on the injection hole inlet side and the curvature radius on the outlet side, the flow coefficient of the fuel passing through the injection hole, and the like. Includes variation.
　そうすると、油圧流量Qhydrのばらつきを解消するにあたり、ノズルの固有の特性に付随する定数αを変更することは不可能であるために、圧力Pを補正することが必要になる。本実施形態においては、基準インジェクタBaseInjのノズルの油圧流量Qhydr_Baseと実機インジェクタ１３のノズルの油圧流量Qhydr_injとの比率を圧力比率に換算して補正係数Xを求め、目標レール圧Prail_tgtに乗算する方法で補正が行われる。 Then, in order to eliminate the variation in the hydraulic flow rate Qhydr, it is impossible to change the constant α associated with the unique characteristics of the nozzle, so it is necessary to correct the pressure P. In this embodiment, the ratio between the hydraulic flow rate Qhydr_Base of the nozzle of the reference injector BaseInj and the hydraulic flow rate Qhydr_inj of the nozzle of the actual injector 13 is converted into a pressure ratio to obtain a correction coefficient X, and multiplied by the target rail pressure Prail_tgt. Correction is performed.
　具体的には、基準インジェクタBaseInj及び実機インジェクタ１３におけるノズルを通過する燃料の流量の比率は、基本的にレール圧に依存しないで一義的に決定されるため、インジェクタの製造時に測定される油圧流量Qhydr_Base、Qhydr_injの比率を換算して得られる圧力比率が、目標レール圧Prail_tgtに乗算されるようになっている。 Specifically, since the ratio of the flow rate of the fuel passing through the nozzles in the reference injector BaseInj and the actual injector 13 is basically determined independently of the rail pressure, the hydraulic flow rate measured when the injector is manufactured. The target rail pressure Prail_tgt is multiplied by the pressure ratio obtained by converting the ratio of Qhydr_Base and Qhydr_inj.
　すなわち、上記式（１）より、基準インジェクタBaseInjの油圧流量Qhydr_Base及び実機インジェクタ１３の油圧流量Qhydr_injは下記式（２）及び（３）で表すことができる。
Qhydr_Base = αbase×√Pbase　…（２）
Qhydr_inj ＝ αinj×√Prail_current　…（３）
αbase ： 基準インジェクタのノズルの油圧流量の公差による定数
αinj ： 実機インジェクタ１３のノズルの油圧流量の公差による定数 That is, from the above equation (1), the hydraulic flow rate Qhydr_Base of the reference injector BaseInj and the hydraulic flow rate Qhydr_inj of the actual injector 13 can be expressed by the following equations (2) and (3).
Qhydr_Base = αbase × √Pbase (2)
Qhydr_inj = αinj × √Prail_current (3)
αbase: Constant due to tolerance of hydraulic flow rate of nozzle of reference injector αinj: Constant due to tolerance of hydraulic flow rate of nozzle of actual injector 13
　ここで、基準インジェクタBaseInjの油圧流量Qhydr_Baseと実機インジェクタ１３の油圧流量Qhydr_injとが等しい場合には、
αbase×√Pbase = αinj×√Prail_current　…（４）
の関係が成り立ち、すなわち、
Prail_current =（αbase／αinj）2×Pbase　…（５）
となる。 Here, when the hydraulic flow rate Qhydr_Base of the reference injector BaseInj and the hydraulic flow rate Qhydr_inj of the actual injector 13 are equal,
αbase × √Pbase = αinj × √Prail_current (4)
That is, that is,
Prail_current = (αbase / αinj) 2 × Pbase (5)
It becomes.
　基準インジェクタBaseInjにおける定数αbaseを１．０とすると、ノズルの油圧流量Qhydrの公差が±２％である場合には下限品のインジェクタにおける定数αinjが０．９８となり、補正後目標レール圧Prail_currentは上記式（５）より、
Prail_current = 1.04×Pbase
となる。 Assuming that the constant αbase in the reference injector BaseInj is 1.0, the constant αinj in the lower limit injector is 0.98 when the tolerance of the nozzle hydraulic flow rate Qhydr is ± 2%, and the corrected target rail pressure Prail_current is the above From equation (5)
Prail_current = 1.04 × Pbase
It becomes.
　一方、基準インジェクタBaseInjにおける定数αbaseを１．０とすると、ノズルの油圧流量Qhydrの公差が±２％である場合には上限品のインジェクタの定数αinjが１．０２となり、補正後目標レール圧Prail_currentは上記式（５）より、
Prail_current = 0.96×Pbase
となる。 On the other hand, when the constant αbase in the reference injector BaseInj is 1.0, when the tolerance of the hydraulic flow rate Qhydr of the nozzle is ± 2%, the constant αinj of the upper limit injector becomes 1.02, and the corrected target rail pressure Prail_current From the above equation (5)
Prail_current = 0.96 × Pbase
It becomes.
　換言すれば、基準インジェクタBaseInjの油圧流量Qhydrの公差、及び実機インジェクタ１３の油圧流量Qhydrの公差が把握できているのであれば、上記式（５）における補正係数X｛＝（αbase／αinj）2｝をあらかじめ設定することができる。実機インジェクタ１３に対応する補正係数Xが設定されれば、補正部７９は、目標レール圧演算部７３で算出される目標レール圧Prail_tgtを上記式（５）のPbaseに代入して、補正後目標レール圧Prail_currentを求めることができる。 In other words, if the tolerance of the hydraulic flow rate Qhydr of the reference injector BaseInj and the tolerance of the hydraulic flow rate Qhydr of the actual injector 13 are known, the correction coefficient X {= (αbase / αinj) 2 in the above equation (5). } Can be set in advance. If the correction coefficient X corresponding to the actual injector 13 is set, the correction unit 79 substitutes the target rail pressure Prail_tgt calculated by the target rail pressure calculation unit 73 for Pbase in the above equation (5), and the corrected target The rail pressure Prail_current can be obtained.
　目標レール圧Prail_tgtが補正されることにより、実機インジェクタ１３の噴射率特性と基準インジェクタの噴射率特性とが一致するようになれば、実機インジェクタ１３の噴射率特性が基準インジェクタBaseInjの噴射率特性よりも高い場合や低い場合であっても、図４に示すように、噴射率波形を基準インジェクタBaseInjの噴射率波形に近似させることができる。これによって、基準インジェクタ１３の燃料噴射量Qactを目標燃料噴射量Qtgtに制御することができるようになる。 When the target rail pressure Prail_tgt is corrected so that the injection rate characteristic of the actual injector 13 matches the injection rate characteristic of the reference injector, the injection rate characteristic of the actual injector 13 is greater than the injection rate characteristic of the reference injector BaseInj. Even if it is high or low, the injection rate waveform can be approximated to the injection rate waveform of the reference injector BaseInj as shown in FIG. As a result, the fuel injection amount Qact of the reference injector 13 can be controlled to the target fuel injection amount Qtgt.
　このとき、製造段階において求められるノズルの油圧流量Qhydrは、少なくとも実際の使用圧力下での油圧流量であることが好ましい。ただし、通電時間ETと燃料噴射量Qactとの関係を示す図２から理解できるように、レール圧が高いほど通電時間ETに伴う燃料噴射量Qactの増加率が大きくなる。すなわち、上限品、中央品、下限品それぞれのインジェクタで同じ量の燃料噴射を実行したときに噴射時間のばらつきが顕著に現れるのは、レール圧が高く燃料噴射量が多いときの噴射時である。そのため、あらゆるレール圧下においてもノズルの油圧流量Qhydrのばらつきを解消することができるようにするためには、蓄圧式燃料噴射装置５０において実現され得る許容最大圧力を含む条件でノズルの油圧流量Qhydrを測定することが好ましい。 At this time, the hydraulic flow rate Qhydr of the nozzle required in the manufacturing stage is preferably at least the hydraulic flow rate under the actual working pressure. However, as can be understood from FIG. 2 showing the relationship between the energization time ET and the fuel injection amount Qact, the increase rate of the fuel injection amount Qact with the energization time ET increases as the rail pressure increases. In other words, when the same amount of fuel is injected in each of the upper limit product, the central product, and the lower limit product, the variation in the injection time is noticeable when the rail pressure is high and the fuel injection amount is large. . Therefore, in order to be able to eliminate the variation in the nozzle hydraulic flow rate Qhydr under any rail pressure, the nozzle hydraulic flow rate Qhydr is set under the condition including the allowable maximum pressure that can be realized in the accumulator fuel injector 50. It is preferable to measure.
　また、ニードル弁のリフト量の影響を排除するためには、ニードル弁のフルリフト領域に相当する通電時間で燃料噴射を実行した場合の燃料噴射量を、異なる２点以上の通電時間において実験的に求め、燃料噴射量の差分を噴射時間の差分で割ることにより、単位時間当たりの油圧流量Qhydrを求めることが好ましい。 Further, in order to eliminate the influence of the lift amount of the needle valve, the fuel injection amount when the fuel injection is executed in the energization time corresponding to the full lift region of the needle valve is experimentally determined at two or more different energization times. It is preferable to determine the hydraulic flow rate Qhydr per unit time by determining and dividing the difference in fuel injection amount by the difference in injection time.
　このようなやり方によって、個々のインジェクタ１３の油圧流量Qhydrを求め、その公差に応じてインジェクタ１３を分類する。そして、蓄圧式燃料噴射装置５０を組み立てる際に、すべての実機インジェクタ１３を同分類のインジェクタ１３によって構成するとともに、目標レール圧Prail_tgtを補正する際の補正係数Xをその油圧流量Qhydrの公差に応じて制御装置７０に設定しておく。これにより、目標レール圧演算部７３で目標レール圧Prail_tgtが求められた場合に、補正部７９では目標レール圧Prail_tgtに補正係数Xを乗算して補正後目標レール圧Prail_currentが求められる。 In such a manner, the hydraulic flow rate Qhydr of each injector 13 is obtained, and the injectors 13 are classified according to the tolerance. Then, when assembling the accumulator fuel injector 50, all the actual injectors 13 are constituted by the same class of injectors 13, and the correction coefficient X when correcting the target rail pressure Prail_tgt is in accordance with the tolerance of the hydraulic flow rate Qhydr. To the control device 70. Thus, when the target rail pressure Prail_tgt is obtained by the target rail pressure calculation unit 73, the correction unit 79 multiplies the target rail pressure Prail_tgt by the correction coefficient X to obtain the corrected target rail pressure Prail_current.
　レール圧制御部７７は、流量制御弁制御部７７ａ及び圧力制御弁制御部７７ｂによって構成され、いずれか一方の制御部によって、あるいは両方の制御部を併用して、レール圧の制御を実行可能に構成されている。レール圧の制御をどの制御部によって実行するかは、内燃機関４０の運転状態によって切り分けられている。このレール圧の基本的な制御は、実レール圧Prail_actが補正後目標レール圧Prail_currentとなるように、流量制御弁８あるいは圧力制御弁１２に供給する電流値をフィードバック制御することによって実行される。本実施形態においては、補正部７９によって求められた補正後の制御レール値Prail_currentを用いてフィードバック制御が実行される。 The rail pressure control unit 77 includes a flow rate control valve control unit 77a and a pressure control valve control unit 77b, and can control rail pressure by either one of the control units or by using both control units in combination. It is configured. Which control unit executes the control of the rail pressure is determined by the operating state of the internal combustion engine 40. This basic control of the rail pressure is executed by feedback-controlling the current value supplied to the flow control valve 8 or the pressure control valve 12 so that the actual rail pressure Prail_act becomes the corrected target rail pressure Prail_current. In the present embodiment, feedback control is executed using the corrected control rail value Prail_current obtained by the correction unit 79.
　インジェクタ制御部８１は、記憶手段にあらかじめ記憶されている基本噴射量マップ情報BaseQmapに基づいてインジェクタ１３の通電時間ETを求めてインジェクタ１３の駆動制御を実行するように構成されている。基本噴射量マップ情報BaseQmapは、レール圧Prailと通電時間ETと燃料噴射量Qとの関係をマップ化したものであり、あらかじめ基準インジェクタBaseInjを用いて作成される。基準インジェクタBaseInjは、例えば、噴射率特性が中央値を示す中央品のインジェクタが用いられるが、中央品以外のインジェクタが基準インジェクタBaseInjとなっていても構わない。 The injector control unit 81 is configured to determine the energization time ET of the injector 13 based on the basic injection amount map information BaseQmap stored in advance in the storage means and execute drive control of the injector 13. The basic injection amount map information BaseQmap is a map of the relationship among the rail pressure Prail, the energization time ET, and the fuel injection amount Q, and is created in advance using the reference injector BaseInj. As the reference injector BaseInj, for example, a central injector having a median injection rate characteristic is used. However, an injector other than the central injector may be the reference injector BaseInj.
　通電時間ETを求める際には、基本的にはレール圧検出部７５で検出される実レール圧Prail_actが用いられるが、本実施形態においては目標レール圧Prail_tgtを補正して得られる補正後目標レール圧Prail_currentによってレール圧制御が実行されるために、実レール圧Prail_actをそのまま用いることができない。実レール圧Prail_actをそのまま用いることは、噴射率特性のばらつきを内包したままで通電時間ETが求められることになる。 When the energization time ET is obtained, the actual rail pressure Prail_act detected by the rail pressure detection unit 75 is basically used. In this embodiment, the corrected target rail obtained by correcting the target rail pressure Prail_tgt is used. Since rail pressure control is executed by the pressure Prail_current, the actual rail pressure Prail_act cannot be used as it is. If the actual rail pressure Prail_act is used as it is, the energization time ET is obtained with the variation in the injection rate characteristic included.
　そこで、インジェクタ制御部８１は、目標レール圧Prail_tgtの補正に用いる補正係数Xの逆数（1/X）を実レール圧Prail_actに乗算して想定レール圧Prail_calを求め、この想定レール圧Prail_calに基づいて通電時間ETを求めるように構成されている。求められる通電時間ETは、目標レール圧Prail_tgtが補正される前の状態で検出され得る実レール圧Prail_actに応じた通電時間と実質的に等しくなる。インジェクタ制御部８１は、求められた通電時間ETに応じて通電制御が実行されるように指示を行う。 Therefore, the injector control unit 81 multiplies the actual rail pressure Prail_act by the reciprocal (1 / X) of the correction coefficient X used for correcting the target rail pressure Prail_tgt to obtain the assumed rail pressure Prail_cal, and based on this assumed rail pressure Prail_cal. It is configured to obtain the energization time ET. The required energization time ET is substantially equal to the energization time according to the actual rail pressure Prail_act that can be detected before the target rail pressure Prail_tgt is corrected. The injector control unit 81 instructs the energization control to be executed according to the obtained energization time ET.
３．燃料噴射制御方法
　次に、制御装置７０による燃料噴射制御方法を実行するための具体的フローの一例について、図５～図８のフローチャートに基づいて詳細に説明する。 3. Fuel Injection Control Method Next, an example of a specific flow for executing the fuel injection control method by the control device 70 will be described in detail based on the flowcharts of FIGS.
　図５は、本実施形態の燃料噴射制御方法を実行するための一連の流れを示している。このうち、主としてステップＳ２及びステップＳ３が制御装置７０による演算処理によって実行されるステップである。 FIG. 5 shows a series of flows for executing the fuel injection control method of the present embodiment. Among these steps, steps S2 and S3 are mainly executed by arithmetic processing by the control device 70.
　まず、ステップＳ１において、目標レール圧Prail_tgtの補正を行うための補正係数Xを制御装置７０に設定する準備工程を行う。図６が、準備工程の具体的なフローチャートを示している。この準備工程において、ステップＳ１１はインジェクタ１３の製造段階で行われるものであり、蓄圧式燃料噴射装置５０において実現され得る許容最大圧力を含む条件で、ニードル弁のフルリフト領域に相当する通電時間におけるノズルの油圧流量Qhydrが個々のノズルごとに測定され、装着されるノズルの油圧流量Qhydrの公差に応じてインジェクタ１３が分類される。 First, in step S1, a preparation process for setting the correction coefficient X for correcting the target rail pressure Prail_tgt in the control device 70 is performed. FIG. 6 shows a specific flowchart of the preparation process. In this preparation process, step S11 is performed in the manufacturing stage of the injector 13, and the nozzle in the energization time corresponding to the full lift region of the needle valve under the condition including the allowable maximum pressure that can be realized in the accumulator fuel injector 50. The hydraulic flow rate Qhydr is measured for each nozzle, and the injectors 13 are classified according to the tolerance of the hydraulic flow rate Qhydr of the mounted nozzle.
　次いで、ステップＳ１２では、油圧流量Qhydrの公差ごとに分類されたインジェクタ１３のうち、例えば中央品のインジェクタを基準インジェクタとして、基本噴射量マップ情報BaseQmapが作成される。 Next, in step S12, basic injection amount map information BaseQmap is created using, for example, the central injector as the reference injector among the injectors 13 classified for each tolerance of the hydraulic flow rate Qhydr.
　次いで、ステップＳ１３では、同じ分類に属するインジェクタ１３を用いて蓄圧式燃料噴射装置５０を構成するとともに、用いられる実機インジェクタ１３の公差に応じて、補正係数Xが制御装置７０に設定される。この補正係数Xは、インジェクタ１３への通電時間ETを求める際にも用いられる。また、制御装置７０には、基準インジェクタBaseInjを用いて作成された基本噴射量マップ情報BaseQmapが記憶される。ステップＳ１１～ステップＳ１３が完了すれば、準備工程が終了する。 Next, in step S13, the pressure accumulation type fuel injection device 50 is configured using the injectors 13 belonging to the same category, and the correction coefficient X is set in the control device 70 according to the tolerance of the actual injector 13 used. This correction coefficient X is also used when obtaining the energization time ET to the injector 13. Further, the control device 70 stores basic injection amount map information BaseQmap created using the reference injector BaseInj. When step S11 to step S13 are completed, the preparation process ends.
　以降、内燃機関４０の運転時には、ステップＳ２及びステップＳ３の各ステップが実行される。
　図７が、ステップＳ２のレール圧制御の具体的なフローチャートを示している。このレール圧制御のフローは所定のサイクルで繰返し行われる。また、図８が、ステップＳ３のインジェクタ１３の制御の具体的なフローチャートを示している。このインジェクタ１３の制御のフローも所定の噴射サイクルで繰返し行われる。 Thereafter, when the internal combustion engine 40 is operated, steps S2 and S3 are executed.
FIG. 7 shows a specific flowchart of the rail pressure control in step S2. This rail pressure control flow is repeated in a predetermined cycle. FIG. 8 shows a specific flowchart of the control of the injector 13 in step S3. The control flow of the injector 13 is also repeatedly performed in a predetermined injection cycle.
　図７に示すように、レール圧制御においては、まず、ステップＳ２１において、機関回転数Neや目標燃料噴射量Qtgt等に基づいて、目標レール圧Prail_tgtが算出された後、ステップＳ２２において、実機インジェクタ１３の油圧流量Qhydrの公差に応じた補正係数Xを目標レール圧Prail_tgtに乗算して補正後目標レール圧Prail_currentが求められる。 As shown in FIG. 7, in the rail pressure control, first, in step S21, the target rail pressure Prail_tgt is calculated based on the engine speed Ne, the target fuel injection amount Qtgt, and the like. The corrected target rail pressure Prail_current is obtained by multiplying the target rail pressure Prail_tgt by a correction coefficient X corresponding to the tolerance of the hydraulic flow rate Qhydr.
　次いで、ステップＳ２３において、レール圧センサ２１を用いて実レール圧Prail_actが検出された後、ステップＳ２４において、補正後目標レール圧Prail_currentと実レール圧Prail_actとの差分に基づいて流量制御弁８又は圧力制御弁１２の通電制御が実行された後に、ステップＳ２１に戻る。
　以上のレール圧制御によって、実機インジェクタ１３の噴射率と基準インジェクタBaseInjの噴射率とが一致するようにレール圧が調節される。 Next, in step S23, after the actual rail pressure Prail_act is detected using the rail pressure sensor 21, in step S24, the flow control valve 8 or pressure is determined based on the difference between the corrected target rail pressure Prail_current and the actual rail pressure Prail_act. After the energization control of the control valve 12 is executed, the process returns to step S21.
By the rail pressure control described above, the rail pressure is adjusted so that the injection rate of the actual injector 13 and the injection rate of the reference injector BaseInj coincide.
　また、図８に示すように、インジェクタ１３の制御においては、まず、ステップＳ３１において、機関回転数Neやアクセル操作量Acc等の内燃機関４０の運転状態に基づいて、目標燃料噴射量Qtgtが算出される。次いで、ステップＳ３２において、レール圧センサ２１を用いて実レール圧Prail_actが検出された後、ステップＳ３３において、補正係数Xの逆数（1/X）を実レール圧Prail_actに乗算して、想定レール圧Prail_calが求められる。 As shown in FIG. 8, in the control of the injector 13, first, in step S31, the target fuel injection amount Qtgt is calculated based on the operating state of the internal combustion engine 40 such as the engine speed Ne and the accelerator operation amount Acc. Is done. Next, in step S32, after the actual rail pressure Prail_act is detected using the rail pressure sensor 21, in step S33, the actual rail pressure Prail_act is multiplied by the reciprocal (1 / X) of the correction coefficient X to obtain the assumed rail pressure. Prail_cal is required.
　次いで、ステップＳ３４において、ステップＳ３３で求めた想定レール圧Prail_calとステップＳ３１で求めた目標燃料噴射量Qtgtとに基づいて、基本噴射量マップ情報BaseQmapから実機インジェクタ１３への通電時間ETが求められる。その後、ステップＳ３５において、通電時間ETに応じて実機インジェクタ１３の通電制御が実行された後に、ステップＳ３１に戻る。 Next, in step S34, the energization time ET to the actual injector 13 is obtained from the basic injection amount map information BaseQmap based on the assumed rail pressure Prail_cal obtained in step S33 and the target fuel injection amount Qtgt obtained in step S31. Thereafter, in step S35, the energization control of the actual injector 13 is executed according to the energization time ET, and then the process returns to step S31.
　以上のように、本実施形態の蓄圧式燃料噴射装置５０によれば、実レール圧Prail_actが実機インジェクタ１３の噴射率特性に応じて調節される一方、実機インジェクタ１３においてはレール圧調節前の状態での通電時間とほぼ同じ通電時間ETで噴射制御が実行されるようになり、実機インジェクタ１３による燃料噴射量Qactが目標燃料噴射量Qtgtに近似するようになる。この方法によれば、噴射時間が補正の前後で大きく変わらないために、排気エミッションが悪化するおそれがなくなる。 As described above, according to the accumulator fuel injection device 50 of the present embodiment, the actual rail pressure Prail_act is adjusted according to the injection rate characteristic of the actual machine injector 13, while the actual machine injector 13 is in a state before the rail pressure adjustment. The injection control is executed with the energization time ET substantially the same as the energization time at, and the fuel injection amount Qact by the actual injector 13 approximates the target fuel injection amount Qtgt. According to this method, since the injection time does not change greatly before and after the correction, there is no possibility that exhaust emission will deteriorate.
　また、製造されるインジェクタ１３のノズルの油圧流量に公差が存在しても、制御装置７０による補正によってインジェクタ１３の噴射率特性に起因する燃料噴射量のばらつきが低減される。したがって、インジェクタ１３の製造段階において、ノズルの製造公差の管理を比較的緩やかにすることができ、インジェクタ１３の製造効率が高められるようになる。 In addition, even if there is a tolerance in the hydraulic flow rate of the nozzle of the manufactured injector 13, variations in the fuel injection amount due to the injection rate characteristics of the injector 13 are reduced by the correction by the control device 70. Therefore, in the manufacturing stage of the injector 13, the management of the manufacturing tolerance of the nozzle can be made relatively loose, and the manufacturing efficiency of the injector 13 can be increased.
　なお、本実施形態においては、目標レール圧Prail_tgtを補正する補正係数Xがノズルの油圧流量Qhydrに基づいて求められるようになっているが、補正係数Xは、インジェクタ１３の噴射率に基づいて求められたものであってもよい。すなわち、インジェクタ１３の製造段階において、実際に製造された個々のインジェクタ１３の噴射率を直接測定して近似する噴射率特性のインジェクタ１３ごとに分類し、基準インジェクタの噴射率と実機インジェクタの噴射率との比率を圧力換算して補正係数を求めるようにしてもよい。 In the present embodiment, the correction coefficient X for correcting the target rail pressure Prail_tgt is obtained based on the hydraulic flow rate Qhydr of the nozzle, but the correction coefficient X is obtained based on the injection rate of the injector 13. It may be what was made. That is, at the stage of manufacturing the injectors 13, the injection rates of the individual injectors 13 actually manufactured are directly measured and classified for each injector 13 having an injection rate characteristic that approximates, and the injection rate of the reference injector and the injection rate of the actual injector The correction coefficient may be obtained by converting the ratio to the pressure.
　また、すでに図２に基づいて説明したように、インジェクタ１３からの噴射流量がニードル弁のリフト量に支配される第１の期間においては、ノズルの油圧流量Qhydrによる燃料噴射量のばらつきの影響が小さいことから、これまで説明した目標レール圧Prail_tgtの補正は、通電時間が第２の期間にある場合にのみ実行するようにしてもよい。このように補正を行う場面を限定することによって、制御装置７０による演算処理の負荷を低減することができる。 Further, as already described with reference to FIG. 2, in the first period in which the injection flow rate from the injector 13 is governed by the lift amount of the needle valve, the influence of the variation in the fuel injection amount due to the hydraulic flow rate Qhydr of the nozzle is affected. Since it is small, the correction of the target rail pressure Prail_tgt described so far may be executed only when the energization time is in the second period. By limiting the scenes where correction is performed in this way, it is possible to reduce the load of calculation processing by the control device 70.
　また、蓄圧式燃料噴射装置５０が内燃機関４０に備えられた後に、従来公知の方法により実機インジェクタ１３の噴射率特性を学習し、学習された噴射率特性によって補正係数Xを更新するように制御装置７０を構成すれば、経時劣化による噴射率特性の変化に対応して、燃料噴射量を目標燃料噴射量に制御することができるようになる。本発明には、このような態様も包含される。 Further, after the pressure accumulating fuel injection device 50 is provided in the internal combustion engine 40, the injection rate characteristic of the actual injector 13 is learned by a conventionally known method, and the correction coefficient X is updated by the learned injection rate characteristic. If the apparatus 70 is configured, the fuel injection amount can be controlled to the target fuel injection amount in response to a change in the injection rate characteristic due to deterioration with time. Such an aspect is also included in the present invention.
　また、本実施形態の制御装置７０の補正部７９は、目標レール圧Prail_tgtに補正係数Xを乗算して実レール圧Prail_actを調節するように構成されているが、補正の対象は、レール圧制御部７７で求められる流量制御弁８又は圧力制御弁１２の制御量であっても同様に燃料噴射量Qactを目標燃料噴射量Qtgtに制御することができる。また、補正の具体的な演算処理方法についても乗算に限られるものではなく、加減算や徐算による方法であってもよい。 In addition, the correction unit 79 of the control device 70 of the present embodiment is configured to adjust the actual rail pressure Prail_act by multiplying the target rail pressure Prail_tgt by the correction coefficient X, but the correction target is rail pressure control. Even with the control amount of the flow control valve 8 or the pressure control valve 12 obtained by the unit 77, the fuel injection amount Qact can be similarly controlled to the target fuel injection amount Qtgt. Further, a specific calculation processing method for correction is not limited to multiplication, and a method by addition / subtraction or gradual calculation may be used.
［第２の実施の形態］
　本発明の第２の実施の形態にかかる蓄圧式燃料噴射装置は、制御装置のレール圧制御部の構成が異なる点以外は、基本的に第１の実施の形態の蓄圧式燃料噴射装置と同様に構成されている。以下、レール圧制御部の構成を中心に、本実施形態の蓄圧式燃料噴射装置について説明する。 [Second Embodiment]
The pressure-accumulation fuel injection device according to the second embodiment of the present invention is basically the same as the pressure-accumulation fuel injection device of the first embodiment except that the configuration of the rail pressure control unit of the control device is different. It is configured. Hereinafter, the pressure accumulation type fuel injection device of the present embodiment will be described focusing on the configuration of the rail pressure control unit.
　本実施形態の蓄圧式燃料噴射装置において、制御装置の記憶手段には、基準インジェクタを用いて作成された基本噴射量マップ情報以外に、インジェクタの噴射率特性に応じた複数の噴射量マップ情報が記憶されている。この噴射量マップ情報は、例えば、インジェクタの製造段階で分類されるインジェクタの噴射率特性に応じて作成される。 In the accumulator fuel injection device of the present embodiment, the storage means of the control device includes a plurality of injection amount map information corresponding to the injection rate characteristics of the injector, in addition to the basic injection amount map information created using the reference injector. It is remembered. This injection amount map information is created, for example, according to the injection rate characteristic of the injector classified at the injector manufacturing stage.
　すなわち、例えば、インジェクタのノズルの製造公差が±２％である場合に、公差が±０である中央品のインジェクタを用いて作成される基本噴射量マップ情報Qmap(0)（BaseQmap）の他、公差が＋２％、＋１％、－１％、－２％のインジェクタを用いてそれぞれ作成される噴射量マップ情報Qmap(+2)、Qmap(+1)、Qmap(-1)、Qmap(-2)が記憶される。 That is, for example, when the manufacturing tolerance of the injector nozzle is ± 2%, in addition to the basic injection amount map information Qmap (0) (BaseQmap) created using the central injector with a tolerance of ± 0, Injection amount map information Qmap (+2), Qmap (+1), Qmap (-1), Qmap (-2) created using injectors with tolerances of + 2%, + 1%, -1%, and -2%, respectively ) Is memorized.
　制御装置には、蓄圧式燃料噴射装置を組み立てる際に用いられる実機インジェクタの噴射率特性の情報が記憶される。例えば、目標レール圧Prail_tgtを補正するための補正係数Xが噴射率特性の情報として用いられてもよい。燃料噴射制御の実行時において、レール圧制御部は、実機インジェクタの噴射率特性に応じた噴射量マップ情報Qmapを用いて、目標燃料噴射量演算手段で算出される目標燃料噴射量Qtgtと、レール圧検出手段で検出される実レール圧Prail_actとに基づいて通電時間ETを求め、実機インジェクタへの通電制御を実行する。 The control device stores information on the injection rate characteristics of the actual injector used when assembling the accumulator fuel injection device. For example, a correction coefficient X for correcting the target rail pressure Prail_tgt may be used as the injection rate characteristic information. At the time of execution of the fuel injection control, the rail pressure control unit uses the injection amount map information Qmap corresponding to the injection rate characteristics of the actual injector, the target fuel injection amount Qtgt calculated by the target fuel injection amount calculating means, the rail The energization time ET is obtained based on the actual rail pressure Prail_act detected by the pressure detecting means, and energization control for the actual injector is executed.
　本実施形態の制御装置による燃料噴射制御方法を実行するための一連の流れは図５のフローチャートと同じであるが、ステップＳ１の準備工程、及びステップＳ３のインジェクタ１３の制御の具体的なフローが第１の実施の形態とは異なる。一方、ステップＳ２のレール圧制御については、図７のフローチャートに沿って実行される。 A series of flow for executing the fuel injection control method by the control device of the present embodiment is the same as the flowchart of FIG. 5, but the specific flow of the preparation process of step S1 and the control of the injector 13 of step S3 is as follows. Different from the first embodiment. On the other hand, the rail pressure control in step S2 is executed along the flowchart of FIG.
　図９は、本実施形態の燃料噴射制御方法を実行するための準備工程の具体的なフローチャートを示している。この準備工程において、ステップＳ４１はインジェクタの製造段階で行われるものであり、蓄圧式燃料噴射装置において実現され得る許容最大圧力を含む条件で、ニードル弁のフルリフト領域に相当する通電時間におけるノズルの油圧流量Qhydrが個々のノズルごとに測定され、装着されるノズルの油圧流量Qhydrの公差に応じてインジェクタが分類される。 FIG. 9 shows a specific flowchart of a preparation process for executing the fuel injection control method of the present embodiment. In this preparatory process, step S41 is performed at the stage of manufacturing the injector, and the nozzle hydraulic pressure during the energization time corresponding to the full lift region of the needle valve under conditions including the maximum allowable pressure that can be realized in the accumulator fuel injection device. The flow rate Qhydr is measured for each nozzle, and the injectors are classified according to the tolerance of the hydraulic flow rate Qhydr of the nozzles to be mounted.
　次いで、ステップＳ４２では、油圧流量Qhydrの公差ごとに分類されたインジェクタそれぞれに対応する複数の噴射量マップ情報Qmapが作成される。次いで、ステップＳ４３では、同じ分類に属するインジェクタを用いて蓄圧式燃料噴射装置を構成するとともに、用いられる実機インジェクタの公差に応じて、補正係数Xが制御装置に設定される。また、制御装置には、インジェクタの分類ごとに作成された複数の噴射量マップ情報Qmapが記憶される。ステップＳ４１～ステップＳ４３が完了すれば、準備工程が終了する。 Next, in step S42, a plurality of injection amount map information Qmap corresponding to each injector classified for each tolerance of the hydraulic flow rate Qhydr is created. Next, in step S43, an accumulator fuel injection device is configured using injectors belonging to the same category, and a correction coefficient X is set in the control device in accordance with the tolerance of the actual injector used. Further, the control device stores a plurality of injection amount map information Qmap created for each injector classification. When steps S41 to S43 are completed, the preparation process ends.
　また、図１０に示すように、インジェクタの制御においては、まず、ステップＳ５１において、機関回転数Neやアクセル操作量Acc等の内燃機関の運転状態に基づいて、目標燃料噴射量Qtgt_tgtが算出される。次いで、ステップＳ５２において、レール圧センサを用いて実レール圧Prail_actが検出された後、ステップＳ５３において、補正係数Xによって定義される実機インジェクタの噴射率特性に応じて、対応する噴射量マップ情報Qmapが選択される。 As shown in FIG. 10, in the control of the injector, first, in step S51, the target fuel injection amount Qtgt_tgt is calculated based on the operating state of the internal combustion engine such as the engine speed Ne and the accelerator operation amount Acc. . Next, in step S52, after the actual rail pressure Prail_act is detected using the rail pressure sensor, the corresponding injection amount map information Qmap is determined in step S53 according to the injection rate characteristic of the actual injector defined by the correction coefficient X. Is selected.
　次いで、ステップＳ５４において、ステップＳ５２で検出された実レール圧Prail_actとステップＳ５１で求めた目標燃料噴射量Qtgtとに基づいて、ステップＳ５３で選択された噴射量マップ情報Qmapから実機インジェクタへの通電時間ETが求められる。その後、ステップＳ５５において、通電時間ETに応じて実機インジェクタの通電制御が実行された後に、ステップＳ５１に戻る。 Next, in step S54, based on the actual rail pressure Prail_act detected in step S52 and the target fuel injection amount Qtgt obtained in step S51, the energization time from the injection amount map information Qmap selected in step S53 to the actual injector. ET is required. Thereafter, in step S55, energization control of the actual injector is executed according to the energization time ET, and then the process returns to step S51.
　このように、制御装置に記憶された複数の噴射量マップ情報の中から実機インジェクタの噴射率特性に応じた噴射量マップ情報が選択されるようになっていれば、検出レール圧Prail_actをそのまま用いて実機インジェクタの通電時間ETを求めることができるようになる。この方法によっても、実レール圧Prail_actが実機インジェクタの噴射率特性に応じて調節される一方、実機インジェクタはレール圧調節前の状態での通電時間とほぼ同じ通電時間ETで噴射制御が実行されるようになり、実機インジェクタによる燃料噴射量Qactが目標燃料噴射量Qtgtに近似するようになる。したがって、排気エミッションが悪化するおそれがなくなるとともに、インジェクタのノズルの製造公差の管理を比較的緩やかにすることができ、インジェクタの製造効率が高められるようになる。 Thus, if the injection amount map information corresponding to the injection rate characteristic of the actual injector is selected from the plurality of injection amount map information stored in the control device, the detected rail pressure Prail_act is used as it is. Thus, the energization time ET of the actual injector can be obtained. Even with this method, the actual rail pressure Prail_act is adjusted in accordance with the injection rate characteristics of the actual machine injector, while the actual machine injector performs injection control with an energization time ET that is substantially the same as the energization time before the rail pressure adjustment. Thus, the fuel injection amount Qact by the actual injector is approximated to the target fuel injection amount Qtgt. Therefore, there is no possibility that the exhaust emission will deteriorate, and the management of the manufacturing tolerance of the nozzle of the injector can be made relatively gradual, and the manufacturing efficiency of the injector can be improved.
　なお、本実施形態においても、目標レール圧Prail_tgtを補正する補正係数Xが、インジェクタの噴射率に基づいて求められたものであってもよい。また、直接補正を行う対象は、目標レール圧Prail_tgtでなくても、流量制御弁８又は圧力制御弁１２の制御量であってもよい。さらに、目標レール圧Prail_tgtの補正は、通電時間が第２の期間にある場合にのみ実行するようにしてもよい。 In this embodiment, the correction coefficient X for correcting the target rail pressure Prail_tgt may be obtained based on the injection rate of the injector. Further, the target to be directly corrected may not be the target rail pressure Prail_tgt but the control amount of the flow control valve 8 or the pressure control valve 12. Furthermore, the correction of the target rail pressure Prail_tgt may be executed only when the energization time is in the second period.
　また、インジェクタの分類ごとに作成された複数の噴射量マップ情報を制御装置に記憶させるのではなく、実機インジェクタの噴射率に対応する噴射量マップ情報のみを制御装置に記憶するようにしてもよい。この場合には、上述のステップＳ５３は省略される。 Also, instead of storing a plurality of injection amount map information created for each injector classification in the control device, only the injection amount map information corresponding to the injection rate of the actual injector may be stored in the control device. . In this case, step S53 described above is omitted.
　また、本実施形態の制御方法にしたがって、インジェクタの経時劣化による噴射率特性の変化に対応して、燃料噴射量を目標燃料噴射量に制御する態様も本願発明に包含される。 Further, according to the control method of the present embodiment, a mode in which the fuel injection amount is controlled to the target fuel injection amount corresponding to the change in the injection rate characteristic due to the deterioration of the injector with time is also included in the present invention.
［第３の実施の形態］
　本発明の第３の実施の形態にかかる蓄圧式燃料噴射装置は、目標レール圧Prail_tgtの補正と併せて通電時間ETを補正し、燃料噴射量Qactを目標燃料噴射量Qtgtに制御するように構成されたものである。目標レール圧Prail_tgtを補正することによって噴射率特性のばらつきを解消することができるものの、噴射率特性以外の要素によって噴射量のばらつきが残るおそれがある。本実施形態の蓄圧式燃料噴射装置は、噴射率特性のばらつきだけでなく、それ以外の要素に起因する噴射量のばらつきをも解消できるように構成されている。 [Third Embodiment]
The accumulator fuel injection apparatus according to the third embodiment of the present invention is configured to correct the energization time ET together with the correction of the target rail pressure Prail_tgt, and to control the fuel injection amount Qact to the target fuel injection amount Qtgt. It has been done. Although the variation in the injection rate characteristic can be eliminated by correcting the target rail pressure Prail_tgt, the variation in the injection amount may remain due to factors other than the injection rate characteristic. The pressure-accumulation fuel injection device according to the present embodiment is configured to be able to eliminate not only variations in injection rate characteristics, but also variations in injection amounts due to other factors.
　通電時間ETの補正方法は従来公知の方法をはじめとして、種々の方法によって実行することができる。以下、本実施形態の蓄圧式燃料噴射装置を構成する制御装置の構成の一例について説明する。 The method for correcting the energization time ET can be executed by various methods including a conventionally known method. Hereinafter, an example of the configuration of the control device constituting the pressure accumulation type fuel injection device of the present embodiment will be described.
　図１１は、本実施形態の制御装置の構成のうち燃料噴射量の補正制御に関連する部分について機能的に表したブロック図を示している。
　この制御装置は、公知の構成からなるマイクロコンピュータを中心に構成されており、目標噴射量演算部１０１と、目標噴射量補正部１０２と、目標レール圧演算部１０３と、レール圧検出部１０５と、レール圧制御部１０７と、目標レール圧補正部１０９と、インジェクタ制御部１１１とを備えている。これらの各部は、具体的にはマイクロコンピュータによるプログラムの実行によって実現される。また、制御装置には、第１の実施の形態又は第２の実施の形態の制御装置７０の構成と同様に記憶手段が備えられている。 FIG. 11 is a block diagram functionally showing a part related to the fuel injection amount correction control in the configuration of the control device of the present embodiment.
This control device is configured around a microcomputer having a known configuration, and includes a target injection amount calculation unit 101, a target injection amount correction unit 102, a target rail pressure calculation unit 103, and a rail pressure detection unit 105. The rail pressure control unit 107, the target rail pressure correction unit 109, and the injector control unit 111 are provided. Specifically, each of these units is realized by executing a program by a microcomputer. In addition, the control device is provided with a storage unit as in the configuration of the control device 70 of the first embodiment or the second embodiment.
　このうち、目標噴射量演算部１０１、目標レール圧演算部１０３、レール圧検出部１０５、レール圧制御部１０７、目標レール圧補正部１０９、及びインジェクタ制御部１１１は、第１の実施の形態又は第２の実施の形態の制御装置を構成する各部と同様に構成されている。 Among these, the target injection amount calculation unit 101, the target rail pressure calculation unit 103, the rail pressure detection unit 105, the rail pressure control unit 107, the target rail pressure correction unit 109, and the injector control unit 111 are the same as those in the first embodiment or It is comprised similarly to each part which comprises the control apparatus of 2nd Embodiment.
　本実施形態の制御装置では、目標燃料噴射量Qtgtの補正を行うための補正量マップ情報ΔQmapが記憶手段に記憶されている。補正量マップ情報ΔQmapは、基準インジェクタBaseInjによる燃料噴射量と実機インジェクタによる燃料噴射量との差分情報をもとに作成されるものであり、レール圧又は目標燃料噴射量が異なる複数の噴射ポイントにおける補正量ΔQが設定されている。この補正量マップ情報ΔQmapが、あらかじめ作成されて記憶されるものであるか、あるいは、制御装置の初期化時等において制御装置内の演算処理によって作成されるものであるかは問わない。 In the control device of the present embodiment, correction amount map information ΔQmap for correcting the target fuel injection amount Qtgt is stored in the storage means. The correction amount map information ΔQmap is created based on the difference information between the fuel injection amount by the reference injector BaseInj and the fuel injection amount by the actual injector, and at a plurality of injection points with different rail pressures or target fuel injection amounts. A correction amount ΔQ is set. It does not matter whether the correction amount map information ΔQmap is created and stored in advance or is created by arithmetic processing in the control device at the time of initialization of the control device or the like.
　目標噴射量補正部１０２は、目標噴射量演算部１０１で算出された目標燃料噴射量Qtgtを補正量マップ情報ΔQmapを用いて補正し、補正後目標燃料噴射量Qtgt_currentを算出するように構成されている。本実施形態の蓄圧式燃料噴射装置では、噴射率特性が同一の分類に属するインジェクタによって実機インジェクタが構成されているために、基本的には一つの補正量マップ情報ΔQmapを用いて、すべての実機インジェクタにおける目標燃料噴射量Qtgtの補正量ΔQを求めることができる。 The target injection amount correction unit 102 is configured to correct the target fuel injection amount Qtgt calculated by the target injection amount calculation unit 101 using the correction amount map information ΔQmap and calculate a corrected target fuel injection amount Qtgt_current. Yes. In the accumulator type fuel injection device of the present embodiment, since the actual machine injectors are constituted by the injectors belonging to the same classification of the injection rate characteristics, basically all the actual machines are used by using one correction amount map information ΔQmap. A correction amount ΔQ of the target fuel injection amount Qtgt in the injector can be obtained.
　目標噴射量補正部１０２は、想定レール圧Prail_cal及び目標燃料噴射量Qtgtに応じた補正量ΔQを補正量マップ情報ΔQmapに基づいて算出する。例えば、補正量マップ情報ΔQmapに設定されている補正量ΔQのうち、制御装置で算出された想定レール圧Prail_cal及び目標燃料噴射量Qtgtに近い噴射ポイントの補正量ΔQから、補正に用いる補正量ΔQを算出する。そして、目標噴射量補正部１０２は、算出された補正量ΔQを目標燃料噴射量Qtgtに加算することによって、補正後目標燃料噴射量Qtgt_currentを算出する。 The target injection amount correction unit 102 calculates a correction amount ΔQ corresponding to the assumed rail pressure Prail_cal and the target fuel injection amount Qtgt based on the correction amount map information ΔQmap. For example, out of the correction amount ΔQ set in the correction amount map information ΔQmap, the correction amount ΔQ used for the correction from the assumed rail pressure Prail_cal calculated by the control device and the correction amount ΔQ of the injection point close to the target fuel injection amount Qtgt. Is calculated. Then, the target injection amount correction unit 102 calculates the corrected target fuel injection amount Qtgt_current by adding the calculated correction amount ΔQ to the target fuel injection amount Qtgt.
　インジェクタ制御部１１１は、算出された補正後目標燃料噴射量Qtgt_currentと想定レール圧Prail_calとに基づいて実機インジェクタへの通電時間ETを求めて、インジェクタの通電制御を実行する。図１２に示すように、目標燃料噴射量Qtgtの補正は、通電時間ETの変化に現れるが、噴射率特性が一致するようにレール圧の制御が行われているために、通電時間ETが微調整される結果、実機インジェクタの噴射時間が基準インジェクタBaseInjの噴射時間と一致することになる。 The injector control unit 111 calculates the energization time ET to the actual injector based on the calculated corrected target fuel injection amount Qtgt_current and the assumed rail pressure Prail_cal, and executes the energization control of the injector. As shown in FIG. 12, the correction of the target fuel injection amount Qtgt appears in the change in the energization time ET. However, since the rail pressure is controlled so that the injection rate characteristics match, the energization time ET is small. As a result of the adjustment, the injection time of the actual injector coincides with the injection time of the reference injector BaseInj.
　本実施形態の蓄圧式燃料噴射装置によれば、レール圧を調節することによって実機インジェクタの噴射率特性が基準インジェクタBaseInjの噴射率特性に合わせられるだけでなく、通電時間ETの微調整によって、実機インジェクタの噴射時間が基準インジェクタBaseInjの噴射時間に一致するようになる。したがって、実機インジェクタによる燃料噴射量Qactが目標燃料噴射量Qtgtにより近づけられ、実機インジェクタと基準インジェクタBaseInjとの間に噴射率特性以外の要素に誤差がある場合であっても、精度よく燃料噴射制御が実行されるようになる。 According to the pressure accumulation type fuel injection device of the present embodiment, by adjusting the rail pressure, not only the injection rate characteristic of the actual injector can be matched to the injection rate characteristic of the reference injector BaseInj, but also by fine adjustment of the energization time ET, The injection time of the injector matches the injection time of the reference injector BaseInj. Therefore, even if the fuel injection amount Qact by the actual injector is made closer to the target fuel injection amount Qtgt, and there is an error in the elements other than the injection rate characteristics between the actual injector and the reference injector BaseInj, the fuel injection control is performed with high accuracy. Will be executed.
１：燃料タンク、２：低圧ポンプ、５：高圧ポンプ、８：流量制御弁、１０：コモンレール、１２：圧力制御弁、１３：インジェクタ（実機インジェクタ）、１４：オーバーフローバルブ、２１：レール圧センサ、４０：内燃機関、４４：回転数センサ、５０：蓄圧式燃料噴射装置、７０：制御装置、７１・１０１：目標噴射量演算部、７３・１０３：目標レール圧演算部、７５・１０５：レール圧検出部、７７・１０７：レール圧制御部、７９・１０９：補正部、８１・１１１：インジェクタ制御部、１０２：目標噴射量補正部 1: fuel tank, 2: low pressure pump, 5: high pressure pump, 8: flow control valve, 10: common rail, 12: pressure control valve, 13: injector (actual injector), 14: overflow valve, 21: rail pressure sensor, 40: Internal combustion engine, 44: Revolution sensor, 50: Accumulated fuel injection device, 70: Control device, 71/101: Target injection amount calculation unit, 73/103: Target rail pressure calculation unit, 75/105: Rail pressure Detection unit, 77/107: Rail pressure control unit, 79/109: Correction unit, 81/111: Injector control unit, 102: Target injection amount correction unit

Claims (12)

  1. 　複数のインジェクタが接続されたコモンレールを備えた蓄圧式燃料噴射装置による内燃機関への燃料噴射制御を行う燃料噴射制御装置において、
    　前記内燃機関の運転状態に基づいて目標燃料噴射量を算出する目標噴射量演算手段と、
    　前記内燃機関の運転状態に基づいて前記コモンレール内の目標圧力を算出する目標レール圧演算手段と、
    　前記コモンレール内の圧力を検出するレール圧検出手段と、
    　前記コモンレール内の圧力を制御するレール圧制御手段と、
    　基準インジェクタを用いて作成された、前記コモンレール内の圧力と通電時間と燃料噴射量との関係を示す基本噴射量マップ情報が記憶された記憶手段と、
    　前記基準インジェクタの噴射率特性と前記インジェクタの噴射率特性との差に基づいて前記目標圧力又は前記レール圧制御手段の制御量を補正する補正手段と、
    　前記基本噴射量マップ情報に基づいて通電時間を求めて前記インジェクタの駆動制御を実行するインジェクタ制御手段と、
    　を備えることを特徴とする燃料噴射制御装置。     In a fuel injection control device for performing fuel injection control to an internal combustion engine by an accumulator fuel injection device having a common rail to which a plurality of injectors are connected,
    Target injection amount calculation means for calculating a target fuel injection amount based on the operating state of the internal combustion engine;
    Target rail pressure calculating means for calculating a target pressure in the common rail based on an operating state of the internal combustion engine;
    Rail pressure detecting means for detecting pressure in the common rail;
    Rail pressure control means for controlling the pressure in the common rail;
    A storage means for storing basic injection amount map information indicating a relationship among the pressure in the common rail, the energization time, and the fuel injection amount, which is created using a reference injector,
    Correction means for correcting the control amount of the target pressure or the rail pressure control means based on the difference between the injection rate characteristic of the reference injector and the injection rate characteristic of the injector;
    Injector control means for determining the energization time based on the basic injection amount map information and executing drive control of the injector;
    A fuel injection control device comprising:
  2. 　前記補正手段が、前記基準インジェクタの噴射率のピークと前記インジェクタの噴射率のピークとが一致するように前記目標圧力又は前記レール圧制御手段の制御量を補正することを特徴とする請求項１に記載の燃料噴射制御装置。 The correction means corrects the control amount of the target pressure or the rail pressure control means so that the peak of the injection rate of the reference injector matches the peak of the injection rate of the injector. A fuel injection control device according to claim 1.
  3. 　前記補正手段が、所定圧力下における前記基準インジェクタのノズルの通過流量と前記インジェクタのノズルの通過流量との比率を変換して得られる圧力比の値に基づいて、前記目標圧力又は前記レール圧制御手段の制御量の補正量を求めることを特徴とする請求項１又は２に記載の燃料噴射制御装置。 The target pressure or the rail pressure control based on a pressure ratio value obtained by converting the ratio between the flow rate of the reference injector nozzle and the flow rate of the injector nozzle under the predetermined pressure. The fuel injection control device according to claim 1, wherein a correction amount of the control amount of the means is obtained.
  4. 　前記所定圧力が、前記蓄圧式燃料噴射装置において実現され得る前記コモンレールの許容最大圧力であることを特徴とする請求項３に記載の燃料噴射制御装置。 The fuel injection control device according to claim 3, wherein the predetermined pressure is an allowable maximum pressure of the common rail that can be realized in the accumulator fuel injection device.
  5. 　所定圧力下における前記基準インジェクタの噴射率及び前記インジェクタの噴射率に基づいて、前記インジェクタの噴射率を前記基準インジェクタの噴射率に一致させるための補正係数があらかじめ求められ、
    　前記補正手段が、前記補正係数を用いて前記目標圧力又は前記レール圧制御手段の制御量を補正することを特徴とする請求項１又は２に記載の燃料噴射制御装置。     Based on the injection rate of the reference injector and the injection rate of the injector under a predetermined pressure, a correction coefficient for matching the injection rate of the injector with the injection rate of the reference injector is obtained in advance.
    3. The fuel injection control device according to claim 1, wherein the correction unit corrects a control amount of the target pressure or the rail pressure control unit using the correction coefficient. 4.
  6. 　前記インジェクタの噴射率又は前記ノズルの通過流量が、前記インジェクタの製造段階において個々のインジェクタごとにあらかじめ求められたものであることを特徴とする請求項３～５のいずれか一項に記載の燃料噴射制御装置。 The fuel according to any one of claims 3 to 5, wherein an injection rate of the injector or a flow rate through the nozzle is obtained in advance for each injector in a manufacturing stage of the injector. Injection control device.
  7. 　前記インジェクタは、ノズルの座面に対して離接可能なニードル弁を離座させることによって前記燃料噴射が行われるものであり、前記インジェクタの通電時間は、前記インジェクタの噴射流量が前記ニードル弁のリフト量に支配される第１の期間と、前記インジェクタの噴射流量が噴孔面積に支配される第２の期間と、からなり、
    　前記インジェクタの通電時間が前記第２の期間である場合に、前記補正手段が前記目標圧力又は前記レール圧制御手段の制御量の補正を実行することを特徴とする請求項１～６のいずれか一項に記載の燃料噴射制御装置。     The injector is configured such that the fuel injection is performed by separating a needle valve that is separable from a seating surface of the nozzle, and the injection flow rate of the injector is equal to the injection flow rate of the needle valve. A first period governed by the lift amount and a second period in which the injection flow rate of the injector is governed by the nozzle hole area;
    The correction means executes correction of the control amount of the target pressure or the rail pressure control means when the energization time of the injector is the second period. The fuel injection control device according to one item.
  8. 　前記目標噴射量演算手段又は前記インジェクタ制御手段が、前記基準インジェクタによる基準燃料噴射量と前記インジェクタによる実燃料噴射量との差分情報に基づいて前記目標燃料噴射量又は前記インジェクタ制御手段の制御量の補正を実行することを特徴とする請求項１～７のいずれか一項に記載の燃料噴射制御装置。 The target injection amount calculating means or the injector control means is configured to determine the target fuel injection amount or the control amount of the injector control means based on difference information between the reference fuel injection amount by the reference injector and the actual fuel injection amount by the injector. The fuel injection control device according to any one of claims 1 to 7, wherein correction is executed.
  9. 　前記インジェクタ制御手段が、前記レール圧検出手段によって検出された前記コモンレール内の圧力に基づいて得られる、前記補正を行わなかった場合の想定レール圧を用いて前記通電時間を求めることを特徴とする請求項１～８のいずれか一項に記載の燃料噴射制御装置。 The injector control means obtains the energization time by using an assumed rail pressure when the correction is not performed, which is obtained based on the pressure in the common rail detected by the rail pressure detection means. The fuel injection control device according to any one of claims 1 to 8.
  10. 　前記記憶手段には、前記基本噴射量マップ情報以外に、前記噴射率特性に応じた複数の噴射量マップ情報が記憶され、
    　前記インジェクタ制御手段が、前記インジェクタの噴射率特性に対応する噴射量マップ情報を選択して前記通電時間を求めることを特徴とする請求項１～８のいずれか一項に記載の燃料噴射制御装置。     In the storage means, in addition to the basic injection amount map information, a plurality of injection amount map information corresponding to the injection rate characteristic is stored,
    The fuel injection control device according to any one of claims 1 to 8, wherein the injector control means obtains the energization time by selecting injection amount map information corresponding to an injection rate characteristic of the injector. .
  11. 　燃料を加圧して圧送する高圧ポンプと、
    　前記高圧ポンプによって圧送される燃料を蓄積するコモンレールと、
    　前記コモンレールに接続された複数のインジェクタと、を備えるとともに、
    　請求項１～１０のいずれか一項に記載の燃料噴射制御装置を備えることを特徴とする蓄圧式燃料噴射装置。     A high-pressure pump that pressurizes and pumps fuel; and
    A common rail that accumulates fuel pumped by the high-pressure pump;
    A plurality of injectors connected to the common rail,
    An accumulator fuel injection apparatus comprising the fuel injection control apparatus according to any one of claims 1 to 10.
  12. 　前記複数のインジェクタとして、それぞれ噴射率特性が近似するインジェクタを備えることを特徴とする請求項１１に記載の蓄圧式燃料噴射装置。 The pressure-accumulation fuel injection device according to claim 11, wherein each of the plurality of injectors includes an injector having an injection rate characteristic approximate to each other.
PCT/JP2011/052802 2010-04-09 2011-02-10 Fuel injection control device and pressure accumulation type fuel injection device WO2011125371A1 (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017057755A (en) * 2015-09-15 2017-03-23 株式会社デンソー Solenoid valve driving device
CN114704398A (en) * 2022-04-11 2022-07-05 哈尔滨工程大学 High-pressure common rail diesel engine fuel injection system based on online sensing as feedback information and PID closed-loop control method thereof

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07238857A (en) * 1994-02-25 1995-09-12 Hino Motors Ltd Fuel injection device
JP2000220508A (en) * 1999-02-01 2000-08-08 Denso Corp Injector and fuel injection system
JP2006200378A (en) * 2005-01-18 2006-08-03 Denso Corp Fuel injection control device, fuel injection valve and adjustment method for fuel injection control

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07238857A (en) * 1994-02-25 1995-09-12 Hino Motors Ltd Fuel injection device
JP2000220508A (en) * 1999-02-01 2000-08-08 Denso Corp Injector and fuel injection system
JP2006200378A (en) * 2005-01-18 2006-08-03 Denso Corp Fuel injection control device, fuel injection valve and adjustment method for fuel injection control

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2017057755A (en) * 2015-09-15 2017-03-23 株式会社デンソー Solenoid valve driving device
CN114704398A (en) * 2022-04-11 2022-07-05 哈尔滨工程大学 High-pressure common rail diesel engine fuel injection system based on online sensing as feedback information and PID closed-loop control method thereof

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