JP4470975B2 - Fuel injection control device and fuel injection system using the same - Google Patents

Description

  The present invention relates to a fuel injection control device that controls an injection amount of a fuel injection valve that performs multi-stage injection in one combustion cycle, and a fuel injection system using the same.

  In a common rail type fuel injection system, multistage injection is performed in which pilot injection, post injection, and the like are performed before and after the main injection that generates main torque for the purpose of reducing combustion noise or regenerating an exhaust filter. .

  Thus, in a multi-stage injection type fuel injection valve that injects fuel multiple times during one combustion cycle, pressure pulsation is generated by a water hammer effect when the fuel injection valve is closed and the injection is terminated in each stage. Since the magnitude of the pressure pulsation changes depending on the elapsed time from the end of each stage of injection, if a pressure pulsation occurs due to the preceding stage in multistage injection, the subsequent stage injection amount to be injected following the preceding stage injection It varies depending on the interval time from the end of injection to the start of subsequent injection.

Therefore, it is conceivable to measure the characteristics of the interval time and pressure pulsation in advance at the time of shipment and set a reference correction map for correcting the injection amount with respect to the interval time.
However, since the injection characteristics of the fuel injection valve vary due to machine differences or changes with time for each fuel injection valve, a deviation occurs between the target interval time and the actual interval time set in the reference correction map. As a result, even if the injection amount of the post-injection at the target interval time is corrected based on the reference correction map, the post-injection amount deviates from the target injection amount.

Therefore, in Patent Document 1, an actual injection amount when multi-stage injection is performed is calculated, and an attempt is made to learn a difference in interval time due to machine difference or temporal change based on the difference between the actual injection amount and the target injection amount.
JP 2007-132334 A

  However, in Patent Document 1, a gap in the interval time in a part of the use range of the interval time is learned, and the learned gap in the interval time is applied to a part of the use range. And in the other use range in the whole use range of interval time, the gap of interval time is newly learned for every range. As a result, there is a problem that the learning amount required for learning the shift in the interval time over the entire use range increases.

  The present invention has been made to solve the above-described problem, and a fuel injection control device that corrects a deviation in the interval time of multistage injection with a small learning amount with high accuracy in the entire use range of the interval time and the same are used. An object is to provide a fuel injection system.

  As shown in FIG. 7 (A), the present inventor, even if the command injection amount is different and the injection rate during injection and the internal pressure of the fuel injection valve (INJ) are different, the inside of the fuel injection valve after the injection is completed. It was found that the change in pressure, that is, the characteristics of pressure pulsation, is almost the same with the elapsed time from the end of injection.

Then, as shown in FIG. 7B, the present inventor shows that the characteristic of the injection amount of the second-stage injection that changes due to the pressure pulsation generated at the end of the first-stage injection in the multistage injection is It has been found that even if the injection amount is different, if the injection end timing of the pre-stage injection and the command injection quantity of the post-stage injection are the same, the interval time between the pre-stage injection and the post-stage injection is almost the same. In FIG. 7B, the interval when the injection amount of the front-stage injection is changed to, for example, 50 mm ³ / st, 10 mm ³ / st, 2 mm ³ / st, and the command injection amount of the rear-stage injection is set to 2 mm ³ / st. The characteristic of the injection quantity of the latter stage injection with respect to time is shown. That is, the variation in the injection characteristic with respect to the interval time due to machine difference or change over time is only the variation in the interval time due to the variation in the on-off valve delay time of the fuel injection valve. Therefore, the injection characteristic with respect to the interval time is merely shifted from the phase of the reference injection characteristic.

Therefore, in the invention according to claims 1 to 5 , the reference injection characteristic for the interval time in the entire use range of the interval time and the actual injection characteristic data for the interval time actually acquired in a part of the use range of the interval time A phase difference with respect to the interval time is calculated, and the injection amount of the subsequent injection is corrected based on the reference injection characteristic corrected by shifting the calculated phase difference.

  As a result, if the reference injection characteristic is measured with high accuracy, the phase difference between the reference injection characteristic and the actual injection characteristic data is obtained by acquiring a part of the actual injection characteristic data instead of the entire use range of the interval time. By shifting, even when the injection characteristics of the fuel injection valve vary due to machine differences or changes over time, the interval time shift can be corrected with high learning accuracy with a small amount of learning in the entire use range of the interval time.

  Here, the reference injection characteristic that changes with respect to the interval time due to the pressure pulsation generated at the end of the pre-stage injection dampens. Even if the injection characteristics of the fuel injection valve vary due to machine differences or changes over time, the actual injection characteristics are those in which the phase of the reference injection characteristics is shifted as described above. Therefore, the position on the interval time of the reference injection characteristic corresponding to the acquired actual injection characteristic data can be specified if there is data for a half cycle of the reference injection characteristic.

Therefore, in the inventions according to claims 1 to 5 , a part of the use range of the interval time for acquiring the actual injection characteristic data is a range including a half cycle of the reference injection characteristic.
As a result, the actual injection characteristic data can be acquired in the usage range of the narrowest interval time, and the phase difference between the reference injection characteristic and the actual injection characteristic data can be calculated. As the range including the half cycle, the position on the interval time of the reference injection characteristic corresponding to the acquired actual injection characteristic data is specified, and the deviation in the interval time direction of the actual injection characteristic data is taken into consideration, and it is slightly less than the half cycle. A large range is sufficient.

In the invention according to claim 2 , the half cycle is between the maximum point and the minimum point of the reference injection characteristic.
In the same half cycle, the displacement of the reference injection characteristic between the maximum point and the minimum point is the largest, so the position of the reference injection characteristic corresponding to the acquired actual injection characteristic data on the interval time can be easily identified. , Can be identified by mistake.

In the third aspect of the present invention, the half cycle is the side where the actual injection amount is small when acquiring the actual injection characteristic data, among the maximum side or the minimum side of the reference injection characteristic.
Thereby, even if fuel is injected from the fuel injection valve in order to acquire actual injection characteristic data, combustion noise and engine torque fluctuation can be suppressed as much as possible.

In the invention according to claim 4 , the half cycle is the shorter interval time in the reference injection characteristics.
Since the reference injection characteristic oscillates damped, the displacement of the reference injection characteristic becomes larger on the shorter interval time side. Thereby, while being able to specify easily the position on the interval time of the reference | standard injection characteristic corresponding to the acquired actual injection characteristic data, it can prevent specifying incorrectly.

Note that a part of the use range of the interval time may be a plurality of ranges in the entire use range of the reference injection characteristics .
By acquiring the actual injection characteristic data in a plurality of ranges instead of one place, it is possible to prevent erroneously specifying the position of the reference injection characteristic corresponding to the acquired actual injection characteristic data on the interval time.

Further, the average phase difference of the phase difference between the reference injection characteristic and the actual injection characteristic data acquired in each of the plural ranges may be calculated, and the reference injection characteristic may be corrected by shifting the average phase difference .

  As a result, even if the phase difference calculated from the actual injection characteristic data acquired in one range is large, the phase difference with a small error is averaged to correct the reference injection characteristic with the phase difference having a large error. Can be prevented.

Further, the reference injection characteristics in each of the plurality of ranges may be corrected by shifting the phase difference calculated in each of the plurality of ranges .
Thereby, when the error of the phase difference calculated from the acquired actual injection characteristic data is small, the phase of the reference injection characteristic can be corrected with high accuracy in the use range where the actual injection characteristic data is acquired.

In addition, the phase difference calculated in each range of the multiple ranges is interpolated with the phase difference in the usage range other than the multiple ranges to calculate the interpolation phase difference, and the reference injection characteristic in the usage range other than the multiple ranges is shifted by shifting the interpolation phase difference. It may be corrected .

Accordingly, the phase of the reference injection characteristic can be corrected without acquiring the actual injection characteristic data in a usage range other than the plurality of ranges in which the actual injection characteristic data is acquired.
The functions of the plurality of means provided in the present invention are realized by hardware resources whose functions are specified by the configuration itself, hardware resources whose functions are specified by a program, or a combination thereof. The functions of the plurality of means are not limited to those realized by hardware resources that are physically independent of each other.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A fuel injection system according to an embodiment of the present invention is shown in FIG.
(Fuel injection system 10)
A fuel injection system 10 according to one embodiment of the present invention is shown in FIG.

  The accumulator fuel injection system 10 includes a feed pump 14, a high-pressure pump 16, a common rail 20, a fuel injection valve 30, an electronic control unit (ECU) 40, and the like. Fuel is injected into each cylinder.

  The feed pump 14 sucks fuel from the fuel tank 12 and supplies it to a high-pressure pump 16 that is a fuel supply pump. The high-pressure pump 16 is a known pump that pressurizes fuel sucked into a pressurizing chamber by a plunger reciprocatingly moved by a drive shaft interlocked with rotation of the crankshaft 66. By controlling the current value supplied to the metering valve 18 of the high-pressure pump 16 by the ECU 40, the fuel suction amount that the high-pressure pump 16 sucks in the suction stroke is metered. Then, by adjusting the fuel intake amount, the fuel discharge amount of the high-pressure pump 16 is adjusted.

  The common rail 20 accumulates fuel pumped by the high-pressure pump 16 and holds the fuel pressure at a predetermined high pressure according to the engine operating state. The pressure sensor 22 detects the fuel pressure inside the common rail 20 and outputs it to the ECU 40.

  The fuel injection valve 30 is installed in each cylinder of the four-cylinder diesel engine 60 and injects fuel accumulated in the common rail 20 into the cylinder. The fuel injection valve 30 performs multi-stage injection including pilot injection, pre-injection, after-injection, and post-injection before and after the main injection that generates main torque in one combustion cycle of the diesel engine.

  As shown in FIG. 2, the fuel injection valve 30 is a known electromagnetically driven valve that controls the fuel injection amount by controlling the pressure in the control chamber 100 that applies fuel pressure to the nozzle needle 32 in the valve closing direction. . High pressure fuel is supplied from the common rail 20 to the periphery of the injection hole 34 of the fuel injection valve 30 and to the control chamber 100.

  In the state shown in FIG. 2 in which the control valve 36 blocks communication between the control chamber 100 and the low pressure side, the nozzle needle 32 closes the nozzle hole 34 by the fuel pressure applied from the control chamber 100 to the nozzle needle 32. .

  When the control valve 36 causes the control chamber 100 to communicate with the low pressure side, the amount of fuel flowing out from the control chamber 100 to the low pressure side becomes larger than the amount of fuel flowing into the control chamber 100 from the common rail 20. descend. As a result, the nozzle needle 32 is lifted and fuel is injected from the injection hole 34.

  As shown in FIG. 1, a microcomputer 50 mounted on an ECU 40 as a fuel injection control device includes a rewritable nonvolatile memory such as a CPU 52, a ROM 54, a RAM 56, and an EEPROM 58, various input / output ports, and the like. . A control program that causes the ECU 40 to function as an actual injection characteristic acquisition unit, a phase difference calculation unit, a phase correction unit, and an injection correction unit, and a reference injection characteristic for the interval time are stored in a storage device such as a ROM 54 or an EEPROM 58. Yes.

  The reference injection characteristics are set over the entire use range of the interval time between the front-stage injection and the rear-stage injection performed after the front-stage injection in the multi-stage injection. The reference injection characteristics may be stored as a map, or may be stored as a mathematical expression such as an approximate expression. In the case of a map, the reference injection characteristics can be acquired in a short time. In the case of the mathematical formula, the storage capacity for storing the reference injection characteristics becomes small. The reference injection characteristic is set for each predetermined pressure range of the common rail pressure in the case of a map, and the common rail pressure is set as a variable in the case of a mathematical expression.

  The ECU 40 determines the operating state of the diesel engine 60 from detection signals of various sensors such as an accelerator sensor that detects the opening (ACC) of the accelerator pedal, a temperature sensor, a pressure sensor 22, and an NE sensor that detects the engine speed (NE). get. The ECU 40 controls energization to the metering valve 18 and the fuel injection valve 30 based on the acquired engine operating state in order to control the diesel engine 60 to an optimal operating state.

  The ECU 40 controls the injection timing and the injection amount of each stage of the fuel injection valve 30 that performs multi-stage injection according to the engine operating state obtained from various sensors including the pressure sensor 22. The ECU 40 outputs a pulse signal as an injection command signal for controlling the injection timing and the injection amount of the fuel injection valve 30.

  The piston 64 accommodated in the cylinder 62 of the diesel engine 60 so as to be reciprocally movable is reciprocally driven when the fuel injected from the fuel injection valve 30 into the combustion chamber 110 burns and expands. The piston 64 is connected to the crankshaft 66 through a connecting rod 65. As the piston 64 reciprocates, the crankshaft 66 rotates.

  The inflow of intake air into the combustion chamber 110 is controlled by opening and closing the intake valve 70, and the exhaust discharged from the combustion chamber 110 is controlled by opening and closing the exhaust valve 74. The intake valve 70 and the exhaust valve 74 are driven to open and close by rotation of cams provided on the cam shafts 72 and 76.

(Change in injection amount due to pressure pulsation)
As shown in FIG. 3, when the fuel injection valve 30 is closed in the multi-stage injection and the pre-stage injection is completed, pressure pulsation is generated in the fuel in the fuel injection valve 30 by the water hammer action. Since this pressure pulsation is transmitted to the common rail 20 as well, the injection timing of the subsequent injection changes depending on the magnitude of the pressure pulsation. As a result, the injection amount of the subsequent injection changes depending on the magnitude of pressure pulsation.

  Further, as shown in FIG. 4, a valve closing delay occurs in the closing of the pre-injection of the fuel injection valve 30 with respect to the falling timing of the drive current that is the injection command signal, and with respect to the rising timing of the driving current. A valve opening delay occurs in the opening of the subsequent injection of the fuel injection valve 30. Therefore, the target interval time (target INT) is set in consideration of the valve closing delay time Tde1 and the valve opening delay time Tds1 with respect to the command interval time (command INT) between the front injection and the rear injection commanded by the drive current. It is necessary. The target interval time is expressed by the following equation (1).

Target INT = command INT−Tde1 + Tds1 (1)
However, since the initial valve closing delay time Tde1 and the valve opening delay time Tds1 vary as Tde2 and Tds2 as indicated by reference numerals 210 and 212 due to machine differences or changes over time of the fuel injection valve 30, the target interval time and the actual interval A time lag indicated by (ΔINT1 + ΔINT2), that is, a phase difference occurs between the time points. As a result, if the post-injection injection amount is corrected at the target interval time point 220 without considering machine differences and changes over time, the post-injection injection amount is corrected at a point different from the actual interval time point 222 to be corrected. Will do.

  As described above, even if the command injection amount for the front stage injection is different and the injection rate during the injection and the internal pressure of the fuel injection valve 30 are different, the pressure pulsation characteristics are the interval time from the end of the front stage injection to the start of the rear stage injection. Is almost the same.

  The characteristic of the injection amount of the subsequent injection that changes due to the pressure pulsation is that the injection end timing of the preceding injection and the command injection amount of the subsequent injection are the same with respect to the interval time even if the injection amount of the preceding injection is different. Are almost identical. Therefore, even if the interval time varies due to machine differences or changes over time, the actual injection characteristic with respect to the interval time is only the phase of the reference injection characteristic shifted. Therefore, it is considered that the phase difference between the reference injection characteristic and the actually measured actual injection characteristic data is calculated, and the injection amount of the subsequent stage injection is corrected by the reference injection characteristic corrected by shifting the phase difference.

(Each means of ECU40)
The ROM 54 or EEPROM 58 of the ECU 40 functions as storage means for storing reference injection characteristics described below. The ECU 40 functions as the following units according to a control program stored in a storage unit such as the ROM 54 or the EEPROM 58.

(1) Storage means In one combustion cycle, the correction value of the injection amount of the subsequent injection with respect to the entire use range of the interval time in the entire use range of the interval time between the pre-stage injection and the post-stage injection injected following the pre-stage injection, The reference injection characteristic is stored in the ROM 54 or the EEPROM 58. The correction value for the injection amount of the post-stage injection is a correction value for the falling timing of the injection command pulse width of the drive current that controls the injection quantity of the post-stage injection. Since the length of the injection command pulse width is changed by changing the falling timing of the injection command pulse width of the drive current, the injection amount of the post-stage injection is changed. The reference injection characteristics are initially set when the fuel injection valve 30 is shipped.

(2) Actual injection characteristic acquisition means The ECU 40 determines that the learning condition is satisfied if the accelerator-off non-injection deceleration operation is being performed, and at a plurality of interval time points in a part of the interval time use range. Subsequent injection is carried out following pre-injection and pre-injection, and an actual injection amount that is a total injection amount by two-stage injection of the pre-injection and the post-injection is measured. The ECU 40 detects a change in the engine speed due to the two-stage injection, converts the engine speed into engine torque, and further converts it into an injection quantity to measure the actual injection quantity. The ECU 40 calculates a correction value for the falling timing of the injection command pulse width of the drive current for controlling the injection amount of the subsequent injection from the actual injection amount measured at each point of the interval time, and calculates the actual injection characteristic data. Get as.

As shown in FIG. 5, the following ranges are conceivable as part of the use range of the interval time for injecting fuel from the fuel injection valve 30 and acquiring the actual injection amount characteristic data.
(2a) Range including the half cycle of the reference injection characteristic 230 Thereby, the actual injection characteristic data can be acquired in the use range of the narrowest interval time, and the phase difference between the reference injection characteristic 230 and the actual injection characteristic data can be calculated. As the range including the half cycle, the position of the reference injection characteristic 230 corresponding to the acquired actual injection characteristic data on the interval time is specified, and the deviation of the actual injection characteristic data in the interval time direction is taken into consideration. It may be a slightly large range.

  For example, in FIG. 5A, the range includes a half cycle between the maximum point and the minimum point of the reference injection characteristic 230 indicated by ΔINTa1, ΔINTa2, and ΔINTa3. In the same half cycle, the displacement between the local maximum point and the local minimum point is the largest, so that the position of the reference injection characteristic 230 at the interval time corresponding to the acquired actual injection characteristic data can be easily specified and specified incorrectly. Can be prevented.

  -Or, between the maximum side and the minimum side of the reference injection characteristic 230, it is the side where the injection amount injected from the fuel injection valve 30 is small in order to acquire the actual injection amount characteristic data. In FIG. 5A, the corrected injection amount of the post-stage injection amount is indicated by ΔINTa4 and ΔINTa5, which are mainly positive. If the corrected injection amount of the subsequent injection amount is positive, it indicates that the actual injection amount is smaller than the reference injection amount. Thereby, even if fuel is injected from the fuel injection valve 30 in order to acquire actual injection characteristic data, combustion noise and engine torque fluctuation can be suppressed as much as possible.

(2b) Shorter interval time in the reference injection characteristic 230 In FIGS. 5A and 5B, the interval time is indicated by ΔINTa1, ΔINTa4, ΔINTb1, and ΔINTb2 from the start to one cycle. Since the reference injection characteristic 230 oscillates damped, the displacement of the reference injection characteristic 230 is larger on the shorter interval time within the same range. Therefore, it is possible to easily specify the position of the reference injection characteristic 230 corresponding to the acquired actual injection characteristic data on the interval time, and to prevent erroneous specification.

  In this case, the use range for acquiring the actual injection characteristic data is not limited to a range including a half cycle such as ΔINTb1 and ΔINTb2. However, in order to prevent the position of the reference injection characteristic 230 corresponding to the actual injection characteristic data from being erroneously specified, it is desirable to acquire the actual injection characteristic data in a use range including a half cycle. In addition, it is desirable to acquire actual injection characteristic data with ΔINTa4 and ΔINTa1 on the shorter interval time including a half cycle.

(2c) A plurality of ranges in the entire use range of the reference injection characteristics 230 For example, actual injection characteristic data is acquired in at least two of the three positions indicated by ΔINTb1, ΔINTb2, and ΔINTb3 in FIG. To do. Each range of the plurality of ranges may be smaller than a half cycle of the reference injection characteristic 230. By acquiring the actual injection characteristic data in a plurality of ranges instead of one place, the position of the reference injection characteristic 230 corresponding to the acquired actual injection characteristic data on the interval time can be easily specified and prevented from being specified by mistake. it can.

(3) Phase difference calculation means The ECU 40 calculates the phase difference between the reference injection characteristic and the actual injection characteristic data.
When the actual injection characteristic acquisition means acquires actual injection characteristic data in a plurality of ranges instead of a single use range, the phase difference for correcting the reference injection characteristics 230 can be calculated as follows.

(3a) The phase difference between the reference injection characteristic 230 and the actual injection characteristic data acquired in each of a plurality of ranges is calculated, and the average phase difference is calculated.
(3b) The phase difference between the reference injection characteristic 230 and the actual injection characteristic data acquired in each of a plurality of ranges is calculated. Therefore, when the error of the phase difference calculated from the acquired actual injection characteristic data is small, the phase of the reference injection characteristic 230 can be corrected with high accuracy in the usage range where the actual injection characteristic data is acquired.

  Then, the phase difference calculated in each of the plurality of ranges is interpolated to calculate an interpolation phase difference in a range other than the plurality of ranges. Therefore, it is not necessary to acquire actual injection characteristic data in the usage range in which the reference injection characteristic 230 is corrected with the interpolation phase difference.

(4) Phase correction means The ECU 40 shifts the calculated phase difference and corrects the phase of the reference injection characteristic 230 shown in FIG.

(4a) When the average phase difference is calculated by the phase difference calculating means, the reference injection characteristic 230 is corrected by shifting the average phase difference.
(4b) When the phase difference between the reference injection characteristic 230 and the actual injection characteristic data acquired in each of the plurality of ranges is calculated by the phase difference calculating unit, the phase difference calculated in each of the plurality of ranges is shifted to a plurality. The reference injection characteristic 230 in each range is corrected.

In a range other than a plurality of ranges, the reference injection characteristic 230 is corrected by shifting the interpolated phase difference calculated by the phase difference calculating means.
(5) Injection correction means The ECU 40 corrects the injection amount of the subsequent injection based on the reference injection characteristic corrected by shifting the phase difference.

(Interval time phase difference learning)
Next, phase difference learning between the reference injection characteristic and the actual injection characteristic with respect to the interval time will be described with reference to FIG. In FIG. 6, “S” represents a step. The learning routine shown in FIG. 6 is always executed during operation of the diesel engine 60.

  In S300, the ECU 40 determines whether or not a non-injection deceleration operation is being performed when the accelerator is off as a phase difference learning condition. If the learning condition is not satisfied, the ECU 40 ends this routine.

  When the learning condition is satisfied, the ECU 40 performs the post-injection after the pre-injection for each point in the partial use range of the entire use range of the interval time, and actually calculates the total injection amount of the pre-stage and the post-stage. Measure as quantity. As a part of the use range for measuring the actual injection amount, any range described in the function of the actual injection characteristic acquisition unit may be used.

  Then, the ECU 40 calculates, for each measurement point, a correction value for the falling timing of the injection command pulse width of the drive current for controlling the injection amount of the post-stage injection from the actual injection amount measured at each interval time point. Obtained as characteristic data.

  In S304, the ECU 40 calculates a phase difference between the reference injection characteristic stored in the ROM 54 or the EEPROM 58 and the acquired actual injection characteristic data. As the phase difference, depending on the use range in which the actual injection characteristic data is acquired in S302, the average phase difference, in the case of multiple ranges, the phase difference of each range, and the multiple ranges interpolating the phase difference of each range of multiple ranges Is appropriately calculated.

In S306, the ECU 40 corrects the phase of the reference injection characteristic by shifting the calculated phase difference, and ends this routine.
The ECU 40 corrects the injection amount of the post-stage injection when performing the multi-stage injection based on the reference injection characteristic shifted in phase difference.

  As described above, in the present embodiment, if the reference injection characteristic is measured with high accuracy, the reference injection characteristic can be obtained only by acquiring a part of the actual injection characteristic data instead of the entire use range of the interval time. By shifting the phase difference from the actual injection characteristic data, even if the injection characteristics of the fuel injection valve 30 vary due to machine differences or changes over time, the interval time shifts with a small amount of learning over the entire use range of the interval time. Can be corrected.

  Further, in the present embodiment, attention is paid to the fact that the difference in the reference injection characteristics with respect to the interval time is not the offset direction, the period, the amplitude, etc., but the phase direction even if the interval time varies due to machine differences or changes over time. . Then, by correcting the post-injection amount by shifting the reference injection characteristic with respect to the interval time in the entire range of use of the interval time by the phase difference from the actual injection characteristic data, the post-injection of the post-injection can be accurately performed over the entire use range of the interval time. The injection amount can be corrected.

[Other Embodiments]
In the above-described embodiment, the injection amount of the post-stage injection is corrected by correcting the falling timing of the injection command signal for the post-stage injection and correcting the injection pulse width. On the other hand, the injection amount of the post-stage injection may be corrected by correcting only the injection timing without changing the pulse width of the injection command signal for the post-stage injection.

  Moreover, in the said embodiment, the correction value of the injection quantity of the back | latter stage injection with respect to interval time was employ | adopted as reference | standard injection characteristic and actual injection characteristic data. On the other hand, you may employ | adopt the total injection quantity of the front | former stage injection and back | latter stage injection with respect to interval time as a reference | standard injection characteristic and real injection characteristic data.

Moreover, you may combine each injection of multistage injection as post-stage injection injected after pre-stage injection and pre-stage injection.
As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

The block diagram which shows the fuel-injection system by this embodiment. The typical sectional view showing the composition of a fuel injection valve. Explanatory drawing explaining generation | occurrence | production of a pressure pulsation. The time chart explaining the gap | interval of interval time. Explanatory drawing which shows the use range of the interval time which acquires real injection characteristic data. The flowchart which shows a phase difference learning routine. (A) shows the relationship between the elapsed time after the end of injection, the injection rate, and the pressure in the fuel injection valve, and (B) is a time chart showing the relationship between the interval time and the injection amount of the post-stage injection.

Explanation of symbols

10: fuel injection system, 16: high pressure pump (fuel supply pump), 20: common rail, 30: fuel injection valve, 40: ECU (fuel injection control device, storage means, actual injection characteristic acquisition means, phase difference calculation means, phase Correction means, injection correction means), 54: ROM (storage means), 58: EEPROM (storage means), 60: Diesel engine (internal combustion engine)

Claims (5)

In a fuel injection control device that controls an injection amount of a fuel injection valve that performs multi-stage injection during one combustion cycle,
Storage means for storing reference injection characteristics with respect to the interval time in the entire use range of the interval time between the preceding injection and the subsequent injection that is injected following the preceding injection;
Actual injection characteristic acquisition means for acquiring actual actual injection characteristic data for a range including a half cycle of the reference injection characteristic as part of the use range of the interval time;
A phase difference calculating means for calculating a phase difference between the reference injection characteristic and the actual injection characteristic data with respect to the interval time;
Phase correction means for correcting the reference injection characteristic by shifting the phase difference;
Injection correction means for correcting the injection amount of the post-stage injection based on the corrected reference injection characteristics;
A fuel injection control device comprising: The fuel injection control device according to claim 1, wherein the half cycle is between a maximum point and a minimum point of the reference injection characteristic . 2. The fuel injection control according to claim 1 , wherein the half cycle is a side having a small actual injection amount when acquiring the actual injection characteristic data, among the maximum side or the minimum side of the reference injection characteristic. apparatus. The fuel injection control device according to any one of claims 1 to 3, wherein the half cycle is a shorter side of the interval time in the reference injection characteristic. A fuel supply pump that pressurizes and pumps fuel; and
A common rail for accumulating fuel pumped by the fuel supply pump;
A fuel injection valve for injecting fuel accumulated in the common rail into a cylinder of an internal combustion engine;
A fuel injection control device according to any one of claims 1 to 4,
A fuel injection system comprising:

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