JP2010106767A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device correctly inject a fuel injection amount, by correcting relation between a fuel injection amount and an injection time in each cylinder as necessary. <P>SOLUTION: The fuel injection device 1A includes: a common rail 4 storing the fuel fed out by a high pressure pump 3B to be an accumulation state; an injector 5A as a direct acting type fuel injection valve, injecting the fuel supplied through a high pressure fuel supply passage 21 branched from the common rail 4, responding to each cylinder of the diesel engine; and an ECU 80A outputting an injection command signal injecting the fuel from the injector 5A. An orifice 75 is disposed to the inside of the high pressure fuel supply passage 21 at a portion close to the common rail 4, and a differential pressure sensor S<SB>dP</SB>detecting differential pressure between upstream and downstream of the orifice 75 is detected. The ECU 80A calculates an actual fuel injection amount based on a signal from the differential pressure sensor S<SB>dP</SB>, and corrects T<SB>i</SB>-Q characteristics representing a correlation between a fuel injection amount Q and an injection time T<SB>i</SB>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel injection device that supplies fuel stored in a pressure accumulation state to a combustion chamber of each cylinder of an internal combustion engine from a fuel injection valve.

  Conventionally, the actual fuel injection amount to each cylinder includes the pressure detected by the pressure sensor provided in the fuel pressure accumulator that stores the fuel sent out by the fuel pump in the pressure accumulation state, and the injection instruction to the fuel injection valve of each cylinder. It was calculated from the fuel injection valve injection time or the number of injections. However, for example, due to manufacturing tolerances of the fuel injection valve, the lift amount of the nozzle needle in the fuel injection valve and the area of the fuel injection hole vary, and the actual fuel injection amount also varies, or the fuel injection to each cylinder When the pressure of the fuel accumulator is pulsated due to the reflection of pressure, etc., and when the injection time and the number of injections of the fuel injection valve are the same between the cylinders, there is a difference in the actual fuel injection amount to each cylinder, There is a possibility that PM (particulate matter) increases and NOx and combustion noise increase.

For example, in Patent Document 1, a fuel accumulator that stores fuel delivered by a fuel pump in an accumulator state, and a fuel that is supplied through a fuel supply passage branched from the fuel accumulator is supplied to the combustion chamber of each cylinder of the internal combustion engine. In a fuel injection device including a fuel injection valve and a control unit that outputs an injection instruction signal for injecting fuel from the fuel injection valve, a difference for detecting a differential pressure in a venturi type narrow portion disposed in a fuel supply passage A technique of a fuel injection device that includes a pressure sensor and that calculates an actual fuel supply amount that passes through a venturi-shaped narrow portion based on a signal from a differential pressure sensor is described.
Japanese Patent Laying-Open No. 2003-184632 (see FIGS. 4 and 12 and paragraphs 0051 to 0058)

However, in the technique described in Patent Document 1, there is a limit to the minimum drawing of the venturi-shaped narrow portion, and it is difficult to draw the tube smoothly and rapidly, and the minimum diameter cannot be sufficiently reduced. It is difficult to form the venturi-type narrow portion with high accuracy. In addition, the occurrence of a differential pressure in the venturi-type narrow portion is small, and it is difficult to accurately calculate the fuel supply amount at the time of fuel injection of the fuel injection valve from the differential pressure in the venturi-type narrow portion.
Therefore, it is difficult to accurately grasp the correlation between the fuel injection amount (Q) from the fuel injection valve and the injection time (T _i ). For example, if the characteristics of the fuel injection valve change due to deterioration over time, the control An error may occur between the target injection amount calculated by the engine unit and the actual fuel injection amount. As a result of such an error, as described above, PM (particulate matter) increases, NOx and combustion noises increase. There is a risk of increase.

  Accordingly, an object of the present invention is to provide a fuel injection device capable of correcting the relationship between the fuel injection amount and the injection time in each cylinder as necessary and injecting the fuel injection amount accurately.

In order to solve the above problems, the present invention provides a fuel accumulator that stores fuel delivered by a fuel pump in an accumulator state, and a fuel supply passage that branches from the fuel accumulator toward each cylinder of an internal combustion engine. A fuel injection valve for supplying the fuel to be supplied to the combustion chamber of each cylinder of the internal combustion engine, a pressure accumulator pressure sensor for detecting the pressure of the fuel pressure accumulator, and a target injection amount of fuel to be injected by the fuel injection valve And a storage unit storing, as data, a T _i -Q characteristic indicating a correlation between the fuel injection amount (Q) of the fuel injection valve and the injection time (T _i ). It was. The T _i -Q characteristic is obtained by regression of data obtained by discretely measuring the correlation between the fuel injection amount (Q) and the injection time (T _i ) at a representative pressure value representative of the pressure of the fuel accumulator. It is indicated by a characteristic line represented by a polynomial obtained by analysis,
The control unit obtains a target injection time corresponding to the target injection amount from the characteristic line based on the pressure of the fuel storage unit detected by the pressure storage unit pressure sensor and the target injection amount. .

According to the present invention, it is possible to calculate a polynomial representing a characteristic line of the T _i -Q characteristic by performing regression analysis on data obtained by discretely measuring the correlation between the fuel injection amount (Q) and the injection time (T _i ). Therefore, the characteristic line of the T _i -Q characteristic can be obtained with a small number of measurements. Therefore, it is possible to reduce the man-hours for obtaining the characteristic line T i _-Q characteristics.

  Further, the present invention is characterized in that in the region where the fuel injection amount (Q) is not less than a predetermined boundary value, the polynomial representing the characteristic line is a first order polynomial.

According to the present invention, in a region where the fuel injection amount (Q) is larger than a predetermined boundary value, a polynomial representing a characteristic line indicating the T _i -Q characteristic can be approximated to a first order polynomial. Therefore, the characteristic line can be simplified in a region where the fuel injection amount (Q) is larger than the predetermined boundary value, and the control load when the control unit obtains the target injection time from the characteristic line can be reduced.

According to the present invention, the T _i -Q characteristic is a plurality of characteristic lines based on a correlation between the fuel injection amount (Q) and the injection time (T _i ) measured for each of the plurality of representative pressure values. And a correlation equation indicating the correlation of the polynomials representing the characteristic lines adjacent to each other is set.

According to the present invention, since the T _i -Q characteristic is indicated by a plurality of characteristic lines, and a correlation equation indicating a correlation of polynomials indicating characteristic lines adjacent to each other is set, the T _i -Q characteristic The relationship between the fuel injection amount (Q) and the injection time (T _i ) can be accurately shown over the entire region.

Further, according to the present invention, when the pressure of the fuel pressure accumulator detected by the pressure accumulator pressure sensor is a value between two representative pressure values, the controller is configured to perform the T _i − at the two representative pressure values. The target injection time corresponding to the pressure of the fuel accumulator is obtained by interpolating the two characteristic lines indicating the Q characteristic.

  According to the present invention, even if the pressure of the fuel pressure accumulating unit is a pressure other than the representative pressure value, the control unit interpolates the characteristic line to thereby achieve the target injection time corresponding to the target injection amount at the pressure of the fuel pressure accumulating unit. Can be calculated with high accuracy.

The present invention further includes an orifice disposed in the fuel supply passage, and a differential pressure sensor that detects a differential pressure upstream and downstream of the orifice in the fuel supply passage, and the fuel injection valve comprises: In the fuel injection, the entire amount of fuel supplied through the fuel supply passage is supplied to the combustion chamber of each cylinder, and the control unit determines the actual fuel injection amount injected by the fuel injection valve during the target injection time. , calculated on the basis of a signal from the differential pressure sensor, wherein when the actual fuel injection amount is different from the target injection amount, and corrects the T _i -Q characteristics.

According to the present invention, it is easy to accurately manufacture the diameter of the orifice opening, and the differential pressure between the upstream side and the downstream side of the orifice is the upstream side and the downstream side of the venturi-type narrow portion. It is larger than the differential pressure between the two and can be used sufficiently for flow rate detection.
Then, the actual fuel injection amount of the fuel injection valve can be accurately calculated based on the detected orifice differential pressure. Even if there is a manufacturing tolerance of the fuel injection valve, the actual fuel injection amount reflecting the influence of the manufacturing tolerance can be calculated, so that an accurate actual fuel injection amount can be calculated. When the calculated target injection amount and the actual fuel injection amount are different, the control unit can correct the T _i -Q characteristic based on the accurate actual fuel injection amount. it can be obtained the corresponding _T i -Q characteristics.

The present invention further includes an orifice disposed in the fuel supply passage, and a fuel supply passage pressure sensor for detecting a pressure downstream of the orifice in the fuel supply passage, wherein the fuel injection valve is a fuel injection valve. In some cases, the entire amount of fuel supplied through the fuel supply passage is supplied to the combustion chamber of each cylinder, and the control unit uses a signal from the pressure accumulator pressure sensor and a signal from the fuel supply passage pressure sensor. And calculating the differential pressure between the upstream side and the downstream side of the orifice based on the differential pressure, and calculating the actual fuel injection amount injected by the fuel injection valve during the target injection time. When it is different from the target injection amount, the T _i -Q characteristic is corrected.

According to the present invention, it is easy to accurately produce the diameter of the orifice opening, and the signal from the pressure accumulator pressure sensor is used as the pressure upstream of the orifice, and the fuel is supplied as the pressure downstream of the orifice. If the signal from the passage pressure sensor is used and the differential pressure is taken, the differential pressure between the upstream side and the downstream side of the venturi-type narrow portion becomes larger, and can be sufficiently used for detecting the flow rate.
The orifice differential pressure is easily calculated from the signal from the pressure accumulator pressure sensor and the signal from the fuel supply passage pressure sensor, and the actual fuel injection amount of the fuel injection valve can be accurately calculated based on the orifice differential pressure. Even if there is a manufacturing tolerance of the fuel injection valve, the actual fuel injection amount reflecting the influence of the manufacturing tolerance can be calculated, so that an accurate actual fuel injection amount can be calculated. When the calculated target injection amount and the actual fuel injection amount are different, the control unit can correct the T _i -Q characteristic based on the accurate actual fuel injection amount. it can be obtained the corresponding _T i -Q characteristics.

The present invention further includes an orifice disposed in the fuel supply passage, and a fuel supply passage pressure sensor for detecting a pressure downstream of the orifice in the fuel supply passage, wherein the fuel injection valve is a fuel injection valve. Sometimes the entire amount of fuel supplied through the fuel supply passage is supplied to the combustion chamber of each cylinder, and the control unit is configured to supply fuel from the fuel injection valve based on a signal from the fuel supply passage pressure sensor. A pressure drop amount associated with the injection of the fuel, and calculating an actual fuel injection amount that the fuel injection valve injects during the target injection time based on the pressure drop amount, and the actual fuel injection amount is the same as the target injection amount. If they are different, the T _i -Q characteristic is corrected.

According to the present invention, it is easy to accurately manufacture the orifice diameter of the orifice, and the signal from the fuel supply passage pressure sensor is used as the pressure downstream of the orifice. Assuming that the pressure based on the signal output from the fuel supply passage pressure sensor when no injection instruction signal is output to the fuel injection valve, that is, the state where no fuel is flowing through the orifice, is the pressure upstream of the orifice, By using the pressure drop amount from the pressure after the injection instruction signal is output to the fuel injection valve as the orifice differential pressure, it can be sufficiently utilized for flow rate detection.
Based on this orifice differential pressure, the actual fuel injection amount of the fuel injection valve can be accurately calculated. Even if there is a manufacturing tolerance of the fuel injection valve, the actual fuel injection amount reflecting the influence of the manufacturing tolerance can be calculated, so that an accurate actual fuel injection amount can be calculated. When the calculated target injection amount and the actual fuel injection amount are different, the control unit can correct the T _i -Q characteristic based on the accurate actual fuel injection amount. it can be obtained the corresponding _T i -Q characteristics.

The present invention further includes an orifice disposed in the fuel supply passage, and a differential pressure sensor that detects a differential pressure upstream and downstream of the orifice in the fuel supply passage, and the fuel injection valve comprises: A part of the fuel supplied through the fuel supply passage at the time of fuel injection is returned to the fuel pipe and discharged to the low pressure part of the fuel supply system, and the control unit passes through the orifice at the target injection time. The flow rate of the fuel passing through the orifice is calculated based on the signal from the differential pressure sensor, and the actual fuel that is actually supplied to the combustion chamber of each cylinder without returning to the return fuel pipe out of the flow rate through the orifice the injection quantity, the calculated on the basis of the orifice passing flow rate and a predetermined coefficient value, the when the actual fuel injection amount is different from the target injection amount that corrects the T _i -Q characteristics And butterflies.

According to the present invention, even a fuel injection device including a so-called back pressure type fuel injection valve is based on an orifice differential pressure detected by a differential pressure sensor, similarly to a fuel injection device including a direct acting fuel injection valve. Thus, the actual fuel injection amount of the fuel injection valve can be accurately calculated. When the calculated target injection amount and the actual fuel injection amount are different, the control unit can correct the T _i -Q characteristic based on the accurate actual fuel injection amount. it can be obtained the corresponding _T i -Q characteristics.

The present invention further includes an orifice disposed in the fuel supply passage, and a fuel supply passage pressure sensor for detecting a pressure downstream of the orifice in the fuel supply passage, wherein the fuel injection valve is a fuel injection valve. Sometimes, a part of the fuel supplied through the fuel supply passage is returned to the fuel pipe and discharged to the low pressure portion of the fuel supply system, and the control unit is configured to output a signal from the pressure accumulator pressure sensor and the fuel. Based on the signal from the supply passage pressure sensor, the differential pressure between the upstream side and the downstream side of the orifice is calculated, and the flow rate of the fuel passing through the orifice during the target injection time is calculated based on the differential pressure. In addition, the actual fuel injection amount that is actually supplied to the combustion chamber of each cylinder without returning to the return fuel pipe out of the flow rate through the orifice, Calculated based on a predetermined coefficient value, the when the actual fuel injection amount is different from the target injection amount, and corrects the T _i -Q characteristics.

According to the present invention, the signal from the pressure accumulator pressure sensor and the fuel supply passage are provided in the fuel injection device having the so-called back pressure type fuel injection valve in the same manner as the fuel injection device having the direct acting fuel injection valve. The orifice differential pressure can be easily calculated based on the signal from the pressure sensor. The actual fuel injection amount of the fuel injection valve can be accurately calculated based on the orifice differential pressure calculated in this way. When the calculated target injection amount and the actual fuel injection amount are different, the control unit can correct the T _i -Q characteristic based on the accurate actual fuel injection amount. it can be obtained the corresponding _T i -Q characteristics.

The present invention further includes an orifice disposed in the fuel supply passage, and a fuel supply passage pressure sensor for detecting a pressure downstream of the orifice in the fuel supply passage, wherein the fuel injection valve is a fuel injection valve. In some cases, a part of the fuel supplied through the fuel supply passage is returned to the fuel pipe and discharged to the low pressure portion of the fuel supply system, and the control unit is based on a signal from the fuel supply passage pressure sensor. And detecting a pressure drop amount accompanying fuel injection from the fuel injection valve, calculating an orifice passage flow rate of fuel passing through the orifice during the target injection time based on the pressure drop amount, and The actual fuel injection amount actually supplied to the combustion chamber of each cylinder without returning to the return fuel pipe is based on the orifice passage flow rate and a predetermined coefficient value. Calculated, the when actual fuel injection amount is different from the target injection amount, and corrects the T _i -Q characteristics.

According to the present invention, even in a fuel injection device including a so-called back pressure type fuel injection valve, the signal output from the fuel supply passage pressure sensor is similar to the fuel injection device including a direct acting fuel injection valve. Based on this, the actual fuel injection amount of the fuel injection valve can be accurately calculated. When the calculated target injection amount and the actual fuel injection amount are different, the control unit can correct the T _i -Q characteristic based on the accurate actual fuel injection amount. it can be obtained the corresponding _T i -Q characteristics.

Further, according to the present invention, when the actual fuel injection amount is different from the target injection amount, the control unit corrects the characteristic line used to obtain the target injection time, thereby obtaining the T _i -Q characteristic. It is characterized by correcting.

According to the present invention, it is possible to correct the T _i -Q characteristics by correcting the characteristic line, a case of correcting the T _i -Q characteristics based on the actual fuel injection amount at a pressure of one fuel accumulator portion also, it is possible to suitably correct the T _i -Q characteristics over the entire region of the pressure of the fuel accumulator portion.

Further, in the present invention, when the T _i -Q characteristic is indicated by a plurality of the characteristic lines and a correlation equation indicating the correlation of the polynomial representing the characteristic lines adjacent to each other is set, the control unit When the actual fuel injection amount is different from the target injection amount, the characteristic line used for obtaining the target injection time is corrected, and the characteristic lines adjacent to each other are sequentially corrected by the correlation equation, The T _i -Q characteristic is corrected.

According to the present invention, when the T _i -Q characteristic is indicated by a plurality of characteristic lines and a correlation equation indicating a correlation of polynomials representing characteristic lines adjacent to each other is set, after correcting one characteristic line, Other characteristic lines can be sequentially corrected using the correlation equation. Therefore, it is possible to suitably correct the entire region of the T _i -Q characteristic based on the correction of one characteristic line.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel injection apparatus which correct | amends the relationship between the fuel injection quantity in each cylinder and the injection time as needed, and can inject the exact fuel injection quantity can be provided.

<< First Embodiment >>
Hereinafter, a fuel injection device according to a first embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.
FIG. 1 is a diagram showing an overall configuration of a pressure accumulation fuel injection device according to the first embodiment, and FIG. 2 is a direct-acting fuel used in the pressure accumulation fuel injection device according to the first embodiment. It is a conceptual lineblock diagram of an injection valve (injector).
The fuel injection device 1A according to the first embodiment includes a low-pressure pump 3A (also referred to as a feed pump) driven by a motor 63 that is electronically controlled by an engine control device (control unit) 80A (hereinafter referred to as an ECU 80A), an engine A high-pressure pump 3B (also referred to as a supply pump) mechanically driven by a driving force extracted from the crankshaft, a common rail (fuel accumulator) 4 to which high-pressure fuel is supplied from the high-pressure pump 3B, an internal combustion engine (not shown), For example, an injector (fuel injection valve) 5A that injects high-pressure fuel into each cylinder of a four-cylinder diesel engine (hereinafter simply referred to as an engine), and an actuator 6A that is built in the injector 5A and electronically controlled by the ECU 80A. , Including.
Here, the low pressure pump 3A and the high pressure pump 3B correspond to the fuel pump described in the claims.

The low pressure pump 3A and the motor 63 are incorporated in the fuel tank 2 together with the filter 62, and supply fuel from the fuel tank 2 to the suction side of the high pressure pump 3B through the low pressure fuel supply pipe 61. The low-pressure fuel supply pipe 61 between the discharge side of the low-pressure pump 3A and the suction side of the high-pressure pump 3B is provided with a flow rate adjusting valve 69 having a strainer 64 and a check valve 68 arranged in series. An omitted differential pressure sensor is provided, and its signal is input to the ECU 80A so that the ECU 80A can detect an abnormality (low pressure fuel supply amount) of the low pressure pump 3A, the filter 62, and the strainer 64.
Further, the return pipe 65 branched from the middle between the strainer 64 of the low-pressure fuel supply pipe 61 and the flow rate adjusting valve 69 returns the excessive fuel supply of the low-pressure pump 3A to the fuel tank 2 via the pressure regulating valve 67. ing.
The high pressure pump 3B, the temperature sensor S _T for detecting the fuel temperature to be discharged is provided. Temperature sensor S _T converts the detected fuel temperature to the temperature signal, and inputs the temperature signal to ECU80A.

The high-pressure fuel discharged from the high-pressure pump 3B to the discharge pipe 70 is stored in a pressure accumulation state in the common rail 4 that is a type of surge tank that accumulates a relatively high-pressure high-pressure fuel. The common rail 4 is provided with a pressure sensor _SPc for detecting the pressure of the common rail (hereinafter referred to as common rail pressure Pc). The pressure sensor _{S Pc} converts the detected pressure signal by detecting the common rail pressure Pc, and inputs the detected pressure signal to ECU80A. The ECU 80A adjusts the opening degree of the pressure adjustment valve 72 disposed in the middle of the return pipe 71 connecting the common rail 4 and the fuel tank 2 based on the input detection pressure signal, and the pressure of the common rail 4 is For example, the pressure is controlled to a predetermined target pressure of 30 MPa to 200 MPa in accordance with the driving state of the vehicle such as the rotation speed.

Further, the common rail 4 is configured to communicate with the injector 5 </ b> A via a high-pressure fuel supply passage (fuel supply passage) 21. Near the common rail 4 of the four high-pressure fuel supply passages 21, orifices 75 are provided, and pressure detection pipes taken out from the upstream side (common rail 4 side) and the downstream side (injector 5A side) of the orifices 75, Each is connected to a differential pressure sensor _SdP . Differential pressure sensor _{S dP} is four orifice differential pressure _{P OR} of the high pressure fuel supply passage 21 respectively detect individually input to ECU80A converts the orifice differential pressure _{P OR} detected respectively differential pressure signal. ECU80A is the differential pressure signal which is input orifice 75 upstream and can get the downstream side of the orifice differential pressure P _OR of, based on further acquired orifice differential pressure P _OR, fuel passing through the orifice 75 The flow rate can be calculated.

In addition, the fuel passage (the fuel passage 25 in the injector 5A and the oil reservoir 20 (see FIG. 2) to be described later) from the position of the orifice 75 to the high-pressure fuel supply passage 21 on the downstream side and the fuel injection hole 10 of the injector 5A is included. The fuel passage volume is the maximum actual fuel supply amount of fuel supplied through the high-pressure fuel supply passage 21 for the explosion stroke in the intake, compression, explosion, and exhaust cycle in one cylinder, for example, the accelerator is stepped on to the maximum extent. Thus, the fuel passage volume exceeds the maximum actual fuel supply amount when the maximum torque is required for the engine (not shown).
Here, the maximum actual fuel supply amount is the integral amount in the case of multistage injection.
Naturally, the piping length of the high-pressure fuel supply passage 21 to the injector 5A of each cylinder of the engine (not shown) varies, and the position where the orifice 75 is provided in the high-pressure fuel supply passage 21 is the above-described fuel passage volume. Is properly adjusted so that each cylinder has the same fuel passage volume.

  Next, the structure of the injector 5A of the first embodiment will be described with reference to FIGS. The injector 5A is attached to each cylinder of an engine (not shown). The injector 5A includes an injector body 13 in which one or more fuel injection holes 10 are formed at the tip, a nozzle needle 14 that is slidably supported in the injector body 13, and the nozzle needle 14 The piston 16 is connected to the upper end side of the nozzle 16 and reciprocally moves integrally with the nozzle needle 14.

The injector body 13 includes a nozzle body 17, a nozzle holder 19, an actuator body 55, and the like. An oil sump 20 is formed in the nozzle body 17 so that the high-pressure fuel is always filled around the nozzle needle 14. The oil sump 20 is always in communication with the common rail 4 via the fuel passage 25 and the high-pressure fuel supply passage 21. The nozzle body 17 is fastened and fixed to the nozzle holder 19 by a retaining nut 22.
The nozzle holder 19 constitutes a cylinder in which a long hole 23 that slidably supports the piston 16 is formed in the longitudinal direction of the central portion. A working chamber 56 that is provided in the actuator body 55 and has a diameter larger than that of the long hole 23 is provided on the long hole 23.

  The nozzle needle 14 is disposed on the same axis as the central axis of the actuator 6 </ b> A, and is slidably supported on the inner periphery of the nozzle body 17. When the nozzle is opened, the nozzle needle 14 is lifted up and a fuel passage is formed between the tip of the nozzle needle 14 and the nozzle body 17 so that the oil reservoir 20 and the fuel injection hole 10 communicate with each other to an engine (not shown). The fuel is injected. When the nozzle is closed, the tip of the nozzle needle 14 is seated on the seat surface 17a of the nozzle body 17 and the injection of high-pressure fuel is terminated.

Next, the actuator 6A will be described with reference to FIG. The actuator 6A includes an actuator body 55 that is fastened and fixed to the upper end surface of the nozzle holder 19 by the retaining nut 31 in a state where the actuator 6A is in liquid-tight contact with the upper end portion of the nozzle holder 19 of the injector 5A. The disposed iron core 33, the electromagnetic coil 34 wound around the housing portion of the iron core 33, the working chamber 56 having a diameter larger than the long hole 23 in the actuator body 55, and the upper end of the piston 16 described above. The piston flange portion 16a is provided, a stopper 36 that restricts the maximum lift amount of the piston flange portion 16a, and a coil spring 37 that biases the piston 16 in the valve closing direction.
A connector (not shown) for supplying power to the electromagnetic coil 34 is assembled to the upper end of the retaining nut 31 in the figure.

The iron core 33 is magnetized when the electromagnetic coil 34 is energized, attracts the piston flange portion 16 a upward, and pulls up the nozzle needle 14 connected to the piston 16. The nozzle needle 14 is lifted up, and fuel is injected from the fuel injection hole 10.
When energization of the electromagnetic coil 34 is stopped, the magnetic force attracting the piston flange portion 16 a disappears, and the piston flange portion 16 a is pushed downward by the urging force of the coil spring 37, and the nozzle needle 14 connected to the piston 16 is moved. Sit on the seat surface 17a. Therefore, fuel injection from the fuel injection hole 10 stops.

Returning to FIG. 1, the ECU 80A includes a microcomputer, an interface circuit, an actuator drive circuit for driving the actuator 6A, and the like (not shown). The microcomputer includes an engine speed sensor, a cylinder discrimination sensor, a crank angle sensor, a water temperature sensor, an intake air temperature sensor, an intake pressure sensor, an accelerator (throttle) opening sensor, a temperature sensor S _T , a pressure sensor (pressure accumulator pressure), not shown. Sensor) A signal from each sensor such as S _Pc and differential pressure sensor S _dP is used to obtain an optimal target injection amount and a target injection time corresponding to the target injection amount to electronically control the actuator 6A.
The ECU 80A includes a storage unit 81 and can store necessary data and the like.
The ECU 80A may include a motor drive circuit that drives the motor 63, or may be configured as a separate unit outside the ECU 80A.
Hereinafter, the contents controlled by the microcomputer included in the ECU 80A are simply expressed as control of the ECU 80A. Further, the hardware configuration of ECUs 80B (see FIG. 9) to 80F (see FIG. 16) in the second to sixth embodiments described later is also the same as that of the ECU 80A.

FIG. 3 is a diagram showing an output pattern of an injection instruction signal for one cylinder and a time transition of fuel behavior in a high-pressure fuel supply passage, (a) is a diagram showing an output pattern of an injection instruction signal, and (b) is an injector. FIG. 4C is a diagram showing the time transition of the actual fuel injection amount from FIG. 1, FIG. 4C is a diagram showing the time transition of the flow rate of the fuel through the orifice, and FIG.
FIG. 1 as appropriate with reference to FIG. 3, the method of calculating the actual fuel injection amount Q _A of the respective cylinders of the fuel in ECU80A with reference to FIG.

In FIG. 3A, the fuel injection instruction signal is conceptually represented by one wide pulse, the rising start time (injection start time) of the injection instruction signal is t _S , and the injection instruction signal rises. down start time (injection end timing) is t _E, falling completion time of the injection instruction signal is t _{E '.}

The injection instruction signal is, for example, electric power output from the ECU 80A and supplied to the electromagnetic coil 34 provided in the actuator 6A of the injector 5A, and is turned ON / OFF by the control of the ECU 80A.
The injector 5A shown in FIG. 1 injects fuel from the fuel injection hole 10 only when the injection instruction signal is ON.
Therefore, the ECU 80A can adjust the total amount of fuel injected from the fuel injection hole 10 of the injector 5A (actual fuel injection amount Q _A ) by adjusting the time during which the injection instruction signal is ON (injection time T _i ).

The injection instruction signal has a rising characteristic that rises with a predetermined inclination from the injection start timing t _S when the ECU 80A is turned on. Similarly, with a falling characteristic falls with a predetermined slope from the injection end timing _{t E} where ECU80A is turned OFF. Therefore, the ECU 80A is configured to control the injection instruction signal in consideration of the rising characteristic and the falling characteristic of the injection instruction signal.

In response to the injection instruction signal output as shown in FIG. 3A, as shown in FIG. 3B, the injector 5A, which is a direct-acting fuel injection valve, has an injection start timing t _S. The fuel injection is started at t _S1 with a little delay, and the injection is ended at t _E1 with a slight delay from the injection end timing t _E.
Further, the amount of fuel passing through the orifice 75 (orifice passage flow rate Q _OR ) is delayed from t _S1 by t _{S2 by} the volume of the fuel passage 25 and the high-pressure fuel supply passage 21, as shown in FIG. Stand up at. Then, similarly back to zero _{t E2} are delayed volume fraction only _{t E1} of the fuel passage 25 and high pressure fuel supply passage 21.

Note that the delay from the injection start timing t _S to t _S1 and t _S2 and the delay from the injection end timing t _E to t _E1 and t _E2 are values inherent to the fuel injection device 1A, and are obtained in advance through experiments or the like. I can leave. Therefore, the ECU 80A can control the fuel injection device 1A in consideration of the delay, and can control the fuel injection device 1A by absorbing the influence of the delay.

As shown in FIG. 3D, the pressure on the upstream and downstream sides of the orifice 75 corresponding to FIG. 3C is the differential pressure even if the upstream pressure on the orifice fluctuates with the fluctuation of the common rail pressure Pc. can be detected orifice differential pressure _{P OR} by sensor _{S dP,} ECU80A can be calculated accurately orifice passing flow _{Q OR.} Then, the area of the region indicated by the orifice passing flow Q _OR dot shown in (c) of FIG. 3, if the injector 5A direct acting, the area of the actual fuel injection amount Q _A shown in FIG. 3 (b) Will be the same.

Incidentally, the flow rate Q _OR of the fuel through the orifice can be easily calculated based on the orifice differential pressure P _OR by the following equation (1).

The injector 5 </ b> A shown in FIG. 2 is “direct acting”, and all of the fuel supplied from the high-pressure fuel supply passage 21 is injected from the fuel injection hole 10. Thus, the amount of fuel supplied from the high pressure fuel supply passage 21 is equal to the actual fuel injection amount Q _A.
Further, the amount of fuel supplied to the high pressure fuel supply passage 21, since equal to the orifice passing flow _{Q OR} orifice 75, ECU80A is the orifice passing flow rate _{Q OR} calculated by Equation (1), the injector 5A it can be regarded as the actual fuel injection amount Q _a.
Therefore, the ECU 80A according to the first embodiment can calculate the actual fuel injection amount Q _A based on the orifice differential pressure P _OR of the orifice 75.

The ECU 80A (see FIG. 1) according to the first embodiment calculates the required torque of an engine (not shown) based on the throttle opening, the engine speed, and the like, and further, the fuel necessary for obtaining the required torque of the engine It has a configuration of calculating the injection amount as the target injection amount Q _t. Then, the ECU 80A obtains a target injection time T _t for the injector 5A to inject the target injection amount Q _t .
Therefore, correlation between the fuel injection amount Q and the injection time _{T i} (hereinafter, referred to as _"T i -Q characteristics") in advance to seek in advance by experiment or the like, for example, the storage unit 81 (see FIG. 1) of ECU80A A configuration for storing the data as data is preferable. This configuration, ECU80A refers to _T i -Q characteristics based on the target injection amount _{Q t} calculated, it is possible to determine the corresponding target injection time _{T t.}

(A) in FIG. 4 _is a diagram showing an example of a characteristic curve _{f Ti} showing a _T i -Q characteristics. T _i -Q characteristics as shown in (a) of FIG. 4, be based on the characteristics of the injector 5A, it can be determined by experiments or the like.
For example, the injection time T _i required for injecting a predetermined fuel injection quantity Q, measured for each fuel injection amount Q, discretely acquires data indicating the relationship between the fuel injection amount Q and the injection time T _i . A characteristic line f _Ti indicating the T _i -Q characteristic can be obtained by performing regression analysis on the acquired data using a least square method or the like to obtain a polynomial.
Thus, T _i -Q characteristics according to the first embodiment, it is possible to obtain on the basis of the small measurement data, an effect that for example can be reduced measurement steps.

Further, T _i -Q characteristics according to the first embodiment has a characteristic that the injection time T _i is increased with an increase in the fuel injection amount Q as shown in (a) of FIG.
Furthermore, polynomial showing the relationship between fuel injection amount Q and the injection time T _i is a non-linear, for large area fuel injection amount Q has been found to be approximating the polynomial linear first-order equation (1 order polynomial). Therefore, T _i -Q characteristics according to the first embodiment, the fuel injection amount Q is larger region was the relationship between the injection time T _i and the fuel injection amount Q to the structure represented by the 1-order polynomial.
Hereinafter, a region where the relationship between the injection time T _i of the T _i -Q characteristic and the fuel injection amount Q is expressed by a first-order polynomial is referred to as a “linear region”, and other regions, that is, the polynomial is nonlinear. The region is referred to as a “nonlinear region”.
The fuel injection amount Q _B that becomes the boundary value between the non-linear region and the linear region can be obtained, for example, by experiments.

_{Further, T} i -Q characteristic changes corresponding to the common rail pressure Pc. (B) in FIG. 4 is a diagram showing a _T i -Q characteristic corresponding to the common rail pressure.
As shown in (b) of FIG. 4, _T i -Q characteristics injector 5A (see FIG. 1) is configured to be determined for each common rail pressure Pc is preferred. For example, a representative pressure value of the common rail pressure Pc is set every 10 MPa, and a T _i -Q characteristic at each representative pressure value is obtained through experiments or the like to obtain a polynomial.
The T _i -Q characteristics required as can be said fuel injection quantity Q of the provisions of the injector 5A at the representative pressure value.

As described above, the common rail pressure Pc is, the ECU80A, from being controlled to a predetermined target pressure in the range of _{30MPa~200MPa, T} i -Q characteristics, a plurality of characteristics corresponding to the common rail pressure Pc of 30MPa from 200MPa Consists of lines. In FIG. 4B, characteristic lines corresponding to the common rail pressure Pc from 110 MPa to 80 MPa are shown as f _{Ti (110) to} f _{Ti (80)} for the sake of explanation.

When obtaining the target injection time _{T t} which corresponds to the calculated target injection amount _{Q t,} ECU80A (see FIG. 1), based on the common rail pressure Pc which computed target injection amount _{Q t} and the pressure sensor _{S Pc} is detected, FIG. Reference is made to the characteristic line f _Ti shown in FIG. At this time, when the common rail pressure Pc is, for example, one of representative pressure values every 10 MPa, the target injection time T _t can be obtained using the characteristic line f _Ti indicating the common rail pressure Pc.
That is, the injection time at which the target injection amount _Qt and the characteristic line _fTi intersect is the target injection time _Tt .

When the common rail pressure Pc is not the representative pressure value, for example, the ECU 80A can obtain the target injection time T _t corresponding to the common rail pressure Pc by interpolating the characteristic line f _Ti of the representative pressure value before and after the common rail pressure Pc. .
Thus, ECU80A _can determine the _T i -Q characteristics refer to the characteristic line _{f Ti} of the target injection amount _{Q t} and the target injection time _{T t} which corresponds to the common rail pressure Pc.

However, when deterioration with time such as, for example, the seat surface 17a (see FIG. 2) wears out, the characteristics of the injector 5A (see FIG. 1) change, and the prescribed fuel injection amount Q of the injector 5A for each representative pressure value changes. , The characteristic line f _Ti of the representative pressure value shown in the T _i -Q characteristic may deviate. As a _result, according to the target injection time _{T t} which is obtained on the basis of the _T i -Q characteristics, ECU80A is Then ON / OFF the injection instruction signal, will be injector 5A is unable to inject the target injection amount _{Q t,} as a result PM (particulate matter) may increase, and NOx and combustion noise may increase.
Therefore, ECU80A the first embodiment, calculates the actual fuel injection quantity _{Q A} on the basis of the orifice differential pressure _{P OR,} based on the actual fuel injection quantity _{Q A} calculated, _T i -Q characteristics as required It was set as the structure which correct | amends.

FIG. 5A is a characteristic line diagram showing the T _i -Q characteristics when the common rail pressure is the representative pressure value Pc ₁ and the representative pressure value Pc ₂ , and FIG. 5B is a correlation equation of adjacent characteristic lines. FIG.
Here, among the plurality of characteristic lines f _Ti indicating the T _i -Q characteristic shown in FIG. 4B, the characteristic line f _{Ti (100)} and the characteristic whose characteristic pressure values are adjacent, such as 100 MPa and 110 MPa, for example. The line f _{Ti (110)} is referred to as a characteristic line adjacent to each other.
A correlation equation indicating a correlation between polynomials representing characteristic lines adjacent to each other is referred to as a “correlation expression indicating a correlation between characteristic lines”.

In the first embodiment, as shown in FIG. 5A, the characteristic line f _{Ti (Pc1)} indicating the T _i -Q characteristic at the common rail pressure Pc ₁ and the T at the common rail pressure Pc ₂ are obtained. _{When there} is a characteristic line f _{Ti (Pc2)} indicating the _i- Q characteristic, as shown in FIG. 5B, a correlation indicating a correlation between the characteristic line f _{Ti (Pc1)} and the characteristic line f _{Ti (Pc2).} The equation k _(Pc1-Pc2) is calculated in advance as a function of the fuel injection amount Q, and stored as data in the storage unit 81 (see FIG. 1) provided in the ECU 80A, for example.
Such a correlation equation k _(Pc1-Pc2) is a ratio of the characteristic line _{fTi (Pc1)} and the characteristic line _{fTi (Pc2)} for each fuel injection amount Q in the first embodiment. That is, the correlation equation k _(Pc1−Pc2) can be obtained by calculating the ratio of the characteristic line _{fTi (Pc1)} and the characteristic line _{fTi (Pc2)} for each fuel injection amount Q and formulating it.
In the first embodiment, the correlation equation k indicating the correlation between all adjacent characteristic lines is calculated.
Note that the conversion coefficient kα shown in FIG. 5B is a value indicating the ratio of the characteristic lines f _Ti adjacent to each other, and is calculated by the correlation equation k.

As shown in FIG. 5 (a), when the common rail pressure of the injection time _{T i1} representative pressure value Pc _1, where the fuel injection amount of the provisions of the injector 5A is _{Q 1,} ECU80A (see FIG. 1) is an orifice differential pressure P _OR the calculated orifice passing flow rate Q _{OR based,} i.e. the actual fuel injection amount is assumed to be Q _a. At this time, the fuel injection amount from the injector 5A (see FIG. 1) is reduced by (Q ₁ -Q _A ), and the amount of fuel injected into the cylinder of the engine (not shown) is reduced.

Therefore, the ECU 80A (see FIG. 1) according to the first embodiment calculates the orifice passage flow rate Q _OR (actual fuel injection amount Q _A ) using the equation (1) based on the orifice differential pressure P _OR . Further, the T _i -Q characteristic is corrected based on the calculated actual fuel injection amount Q _A.

なお、式（２）において、αは、コモンレール圧力がＰｃ_１で噴射時間Ｔ_ｉ１のときの規定の燃料噴射量Ｑ_１と実燃料噴射量Ｑ_Ａの差（Ｑ_１−Ｑ_Ａ）であり、βは、噴射時間Ｔ_ｉ１における実燃料噴射量Ｑ_Ａと、コモンレール圧力が代表圧力値Ｐｃ_２で噴射時間Ｔ_ｉ１のときの規定の燃料噴射量Ｑ_２との差（Ｑ_Ａ−Ｑ_２）である。 For example, ECU80A (see FIG. 1), the common rail pressure is calculated and the fuel injection amount _{Q 1} and the actual fuel injection quantity _{Q A} defined when the injection time _{T i1} representative pressure value Pc _1.
Further, based on the characteristic line f _{Ti (Pc2)} of the representative pressure value Pc ₂ adjacent to the common rail pressure Pc ₁ , the ECU 80A defines the specified fuel injection amount when the common rail pressure is the representative pressure value Pc ₂ and the injection time T _i1. to calculate the Q _2. Then, the ECU 80A calculates the correction amount Δf by the following equation (2).

In the equation (2), α is a difference (Q ₁ −Q _A ) between the specified fuel injection amount Q ₁ and the actual fuel injection amount Q _A when the common rail pressure is Pc ₁ and the injection time T _i1 . β is the actual fuel injection amount _{Q a} of the injection time _{T i1,} the difference between the fuel injection amount _{Q 2} defined when the injection time _{T i1} common rail pressure is representative pressure value Pc _{2 (Q} a -Q ₂₎ is there.

Then, the ECU 80A (see FIG. 1) multiplies the fuel injection amount Q of the characteristic line fTi ( _{Pc1) by} the correction amount Δf at all injection times Ti to correct the characteristic line _{fTi (Pc1). Ti (Pc1)} ′ is obtained.
For the characteristic line f _{Ti (Pc2)} adjacent to the characteristic line f _{Ti (Pc1)} , the characteristic line f _{Ti (Pc2)} is corrected by multiplying the fuel injection amount Q at all injection times Ti by the correction amount Δf. A characteristic line f _{Ti (Pc2)} ′ is obtained.
Similarly, for the other characteristic lines f _Ti , the corrected characteristic line f _Ti ′ can be obtained by multiplying the fuel injection amount Q by the correction amount Δf, and the Ti-Q characteristic can be corrected.

Thus, by calculating the actual fuel injection amount Q _A of one representative pressure value Pc _1, it can be corrected the entire area of the Ti-Q characteristic. That, ECU80A, based on the correction of one characteristic line _{f Ti,} can be corrected the entire area of the _T i -Q characteristics.

Further, for example, when the actual fuel injection amount Q _A of when the common rail pressure Pc is not the representative pressure value is calculated, ECU80A (see FIG. 1), based on the actual fuel injection amount Q _A, for example, T _i as follows -Q characteristics can be corrected.

Figure 6 is a conceptual diagram for correcting the characteristic line T i _-Q characteristics.
As shown in FIG. 6, when the common rail pressure detected by the pressure sensor S _Pc (see FIG. 1) is Pc _A between _two representative pressure values Pc ₁ and Pc ₂ (indicated by a point A ₁ ), the ECU 80A (see FIG. 1). For example, the target injection times T _it1 and T _it2 obtained from the characteristic lines f _{Ti (Pc1)} and f _{Ti (Pc2) of the} representative pressure values Pc ₁ and Pc ₂ across the common rail pressure Pc _A are proportionally distributed, for example. Then, a target injection time T _iC corresponding to the target injection amount Q _t when the common rail pressure is Pc _A is obtained.
That is, the target injection time T _iC at the common rail pressure Pc _A is obtained by interpolating the characteristic line f _{Ti (Pc1)} and the characteristic line f _{Ti (Pc2)} .

Thus according to the target injection time _{T iC} obtained when ECU80A (see FIG. 1) is the injection instruction signal to ON / OFF to the injector 5A (see FIG. 1) was injected fuel, ECU80A orifice passing flow Q actual fuel injection amount _{Q a} calculated based on the _OR is different from the target injection amount _{Q t,} when reduced by _(Q t -Q _a) reduction alpha _d represented by (shown at point _{a 2),} ECU80A is The characteristic line f _{Ti (Pc1)} is corrected.

Specifically, the ECU 80A (see FIG. 1) calculates a decrease amount α _d of the fuel injection amount. Furthermore, ECU80A, as shown in FIG. 6, the fuel injection amount to _{Q 1} defined injector 5A (see FIG. 1) when the injection time the common rail pressure is representative pressure value Pc ₁ the target injection time _{T iC,} characteristics Calculation is based on the line f _{Ti (Pc1)} . That is, the fuel injection amount Q ₁ at the point A ₃ is obtained.
ECU80A regards the fuel injection amount to _{Q 1} defined at point _{A 3} is also reduced by reducing the amount of alpha _d, fuel injection amount has decreased by decreasing the amount alpha _d from the fuel injection amount to _{Q 1} defined when the injection time _{T iC} Q ₁ 'is calculated (indicated by the point _{a 4).}

なお、式（３）において、α_ｄは前記した減少量であり、β_ｄは、特性線ｆ_{Ｔｉ（Ｐｃ１）}上で噴射時間Ｔ_ｉＣのときの規定の燃料噴射量Ｑ_１から減少量α_ｄだけ減少した燃料噴射量Ｑ_１’と、コモンレール圧力が代表圧力値Ｐｃ_２で噴射時間Ｔ_ｉＣのときの規定の燃料噴射量Ｑ_２との差（Ｑ_１’−Ｑ_２）である。 Further, the ECU 80A, based on the characteristic line f _{Ti (Pc2)} of the representative pressure value Pc ₂ adjacent to the representative pressure value Pc ₁ , when the common rail pressure is the representative pressure value Pc ₂ and the injection time _TiC , that is, the point A ₅ to calculate the fuel injection amount Q ₂ defined in. Then, ECU80A is by the following equation (3), calculates a correction amount Delta] f _d.

In Expression (3), α _d is the above-described decrease amount, and β _d is the decrease amount α _d from the prescribed fuel injection amount Q ₁ at the injection time T _iC on the characteristic line f _{Ti (Pc1).} This is a difference (Q ₁ ′ −Q ₂ ) between the fuel injection amount Q ₁ ′ that is decreased by a predetermined amount and the fuel injection amount Q ₂ when the common rail pressure is the representative pressure value Pc ₂ and the injection time T _iC .

Then, ECU80A (see FIG. 1) in all of the injection time _{T i,} multiplied by the correction amount Delta] f _d to the fuel injection amount Q characteristic line _{f Ti (Pc1),} and corrects the characteristic line _{f Ti (Pc1)} properties A line f _{Ti (Pc1)} ′ is obtained.
As for the characteristic line _{f Ti (Pc1)} and the adjacent characteristic line _{f Ti (Pc2),} multiplied by the correction amount Delta] f _d to the fuel injection amount Q in all injection time _{T i,} the characteristic line _{f Ti (Pc2)} A corrected characteristic line f _{Ti (Pc2)} ′ is obtained.
Similarly, for the other characteristic lines f _Ti , the corrected characteristic line f _Ti ′ can be obtained by multiplying the fuel injection amount Q by the correction amount Δf _d , and the T _i -Q characteristic can be corrected.

Thus, by calculating the actual fuel injection amount Q _A at one common rail pressure Pc _A , the entire region of the T _i -Q characteristic can be corrected. That, ECU80A, based on the correction of one characteristic line _{f Ti,} can be corrected the entire area of the _T i -Q characteristics.

Further, as described above, T _i -Q characteristics of the present embodiment, since you have previously obtained a correlation equation k indicating the correlation between the characteristic line f _Ti adjacent to each other, and correcting a single characteristic line f _Ti Thereafter, another characteristic line f _Ti may be corrected using the correlation equation k.

Figure 7 is a conceptual diagram is corrected based on the T i _-Q characteristics correlation equation. As shown in FIG. _7, the _T i -Q characteristics, the common rail pressure _Pc 1 is a representative pressure _value, Pc 2, Pc ₃ characteristic line _{f Ti (Pc1), f Ti} (Pc2), f Ti (Pc3) is Consider a case where the characteristic line f _{Ti (Pc1)} is corrected to a characteristic line f _{Ti (Pc1)} ′ indicated by a broken line.

As described above, in the first embodiment, the correlation equation k _(Pc1-Pc2) indicating the correlation between the characteristic line f _{Ti (Pc1)} and the characteristic line f _{Ti ( Pc2)} is obtained in advance and stored in the ECU 80A. It is stored in the unit 81 (see FIG. 1). Similarly, a correlation equation k _(Pc2-Pc3) indicating the correlation between the characteristic line f _{Ti (Pc2)} and the characteristic line f _{Ti ( Pc3)} is obtained in advance and stored in the storage unit 81 of the ECU 80A, for example.

Therefore, ECU80A (see FIG. 1) is in the correction of the characteristic line _{f Ti (Pc1)} characteristic line _{f Ti (Pc1)} ', the conversion coefficient kα that every fuel injection amount Q is determined by the correlation equation _{k (Pc1-Pc2)} can be obtained multiplication to the characteristic line _{f Ti} can be regarded as the correction of the _(Pc2) characteristic line _{f Ti (Pc2)} '. Further, the ECU 80A can be regarded as correcting the characteristic line _{fTi (Pc3)} by multiplying the characteristic line fTi _(Pc2) ′ by the conversion coefficient kα obtained by the correlation equation k _(Pc2−Pc3) for each fuel injection amount Q. A characteristic line f _{Ti (Pc3)} ′ can be obtained.
That is, it is possible to obtain a characteristic line _{f Ti (Pc1)} 'by multiplying the correlation equation _{k (Pc1-Pc2)} to the characteristic line _{f Ti (Pc2)',} the characteristic line _{f Ti (Pc2)} 'the correlation equation _{k ( The} characteristic line f _{Ti (Pc3)} ′ can be obtained by multiplying by _Pc2−Pc3) .

Incidentally, in FIG. 7 is a conceptual diagram for correcting the three characteristic lines _{f Ti} is _shown, even if the _T i -Q characteristics there are more than two characteristic lines _{f Ti,} ECU80A (see FIG. 1 ) Can sequentially correct all the characteristic lines f _Ti and can suitably correct the entire region of the T _i -Q characteristic.

Thus, ECU80A (see FIG. 1) utilizes a correlation equation k indicating the correlation between the characteristic line _{f Ti} adjacent to each _other, it can be corrected for all characteristic line _{f Ti} of _T i -Q characteristics. That is, the ECU 80A can suitably correct the T _i -Q characteristic.

More ECU80A according to the first embodiment (see FIG. 1) as is, since it can be calculated accurately orifice passing flow rate _{Q OR} based on the orifice differential pressure _{P OR} orifice 75 (see FIG. 1), accurately injector 5A can be calculated actual fuel injection amount Q _a (see FIG. 1).
Then, ECU80A, based on the actual fuel injection amount _{Q A,} makes it possible to correct accurately _T i -Q characteristics.
Therefore injector 5A can be injected fuel accurately target injection amount Q _t into the cylinder of the engine (not shown), or increases the PM (particulate matter), preferably that the NOx and combustion noise or increasing Can be suppressed.

Figure 8 is a flowchart showing a procedure of the ECU corrects the _T i -Q characteristics. Referring mainly to FIG. 8, ECU80A (see FIG. 1) illustrating a procedure of correcting the _T i -Q properties (see appropriately FIGS. 1 7).
Hereinafter, a procedure in which the ECU 80A corrects the T _i -Q characteristic is referred to as a “correction procedure”.

For example, the correction procedure may be incorporated as a subroutine in a program executed by the ECU 80A and executed when the ECU 80A turns on an injection instruction signal for the injector 5A. Therefore, ECU80A, based on the throttle opening and the engine rotational speed has already calculated the target injection amount _{Q t.}
Further, ECU80A, based on the common rail pressure Pc to the target injection amount _{Q t} and the pressure sensor _{S Pc} is detected, and calculates the target injection time _{T t.}

ECU80A, upon ON the injection instruction signal to start the execution of the correction procedure, by equation (1), calculates the orifice passing flow rate _{Q OR} based on the orifice differential pressure _{P OR} (step S1). Injector 5A according to the first embodiment, since a direct-acting, the orifice passing flow Q _OR can be regarded as the actual fuel injection amount Q _A of the injector 5A. Therefore, ECU80A would calculates an actual fuel injection amount _{Q A.}

ECU80A is, until the target injection time _{T t} is OFF the injection instruction signal has elapsed (step S2 → No), then calculates the orifice passing flow rate _{Q OR} returns control to step S1, After OFF the injection instruction signal ( step S2 → Yes), compares the actual fuel injection quantity _{Q a} and the calculated target injection amount _{Q t} (step S3).
That, ECU80A calculates the orifice passing flow rate Q _OR of the injection instruction signal from the ON to the target injection time T _t has elapsed and the actual fuel injection quantity Q _A, to be compared with the target injection amount Q _t Become.

If the actual fuel injection amount _{Q A} and the target injection amount _{Q t} are equal (step S3 → Yes), ECU80A ends the correction procedure. That is, when the correction procedure is executed in a subroutine, the ECU 80A returns to the execution of the main routine.
On the other hand, when the actual fuel injection amount _{Q A} and the target injection amount _{Q t} is not equal to (step S3 → No), ECU80A is 5, as shown in FIG. 6, a characteristic line of closest representative pressure value in common rail pressure Pc f _Ti is corrected (step S4).

Furthermore, ECU80A, based on the corrected characteristic line _{f Ti,} 5, 6 or _7, to correct all of the characteristic line _{f Ti} of _T i -Q characteristics. That is, the ECU 80A corrects the T _i -Q characteristic (step S5).

The T _i -Q characteristic corrected as described above is based on a change in the characteristic of the injector 5A, and the ECU 80A calculates the target injection time T _t corresponding to the target injection amount Q _t . by referring to the corrected T _i -Q characteristics can calculate the target injection time T _t in response to changes in the characteristics of the injector 5A.
Therefore, for example, even when the characteristics of the injector 5A change due to wear of the seat surface 17a (see FIG. 2) due to deterioration over time, the ECU 80A accurately adds the target injection amount Q _t to the cylinder of the engine (not shown). Therefore, it is possible to suitably suppress an increase in PM (particulate matter) and an increase in NOx and combustion noise.

Further, in the first embodiment, it is easy to accurately manufacture the opening diameter of the orifice 75 (see FIG. 1), and the orifice differential pressure P _OR between the upstream side and the downstream side of the orifice 75 is easy. Is larger than the differential pressure between the upstream side and the downstream side of the venturi-type narrow portion, and the orifice passage flow rate Q _OR is easily calculated from the orifice differential pressure P _OR by the differential pressure sensor S _dP by the equation (1). it can.
Then, in the direct-acting injector 5A (see FIG. 1), the actual fuel injection amount Q _A from equal to the orifice passing flow Q _OR, the actual fuel injection amount Q _A can be accurately calculated.

Therefore, the actual even if manufacturing tolerances of the injector 5A (see FIG. 1), it is possible to calculate the actual fuel injection amount Q _A that reflects the influence of the manufacturing tolerances, for example, ECU80A (see FIG. 1) is calculated based on the fuel injection quantity Q _a and the target injection amount Q _t, it makes it possible to correct accurately T _i -Q characteristics.
As a result, the injector 5A can be injected fuel accurately target injection amount Q _t into the cylinder of the engine (not shown), or increases the PM (particulate matter), the NOx and combustion noise or increasing Can be suitably suppressed.

Also, be varied orifice upstream side pressure in accordance with the variation of the common rail pressure Pc, ECU80A (see FIG. 1) is a differential pressure sensor _{S dP} by detectable orifice differential pressure _{P OR,} further orifice passing flow rate _{Q OR} Can be calculated.
ECU80A Therefore, even if the common rail pressure Pc varies, the actual fuel injection amount Q _A can be calculated accurately.
Therefore, even when the common rail pressure Pc fluctuates, the ECU 80A can correct the T _i -Q characteristic with high accuracy.

In addition, the fuel injection from the injector 5A is actually “Pilot injection” for the purpose of reducing PM (particulate matter), NOx and combustion noise, and activating the catalyst by raising exhaust gas temperature and supplying reducing agent. "," Pre (injection) "," After (injection) "and" Post (injection) "multi-stage injection.
And, in such a multi-stage injection, the respective cylinders can not be ensured target injection amount Q _t, it may not be clear limits for exhaust gas of the engine.

For example, even if you like the seat surface 17a by deterioration over time (see FIG. 2) is wear characteristics of the injector 5A changes, the actual fuel injection amount Q _A prescribed amount can no longer be ensured, ECU80A is by executing the correction procedure, can be corrected T _i -Q characteristics in response to changes in the characteristics of the injector 5A, it can be secured target injection amount Q _t.

  As a result, it is easy to clear the exhaust gas regulations even if the requirements for hardware specifications such as dimensional tolerances on individual parts of the engine system are relaxed. In particular, the hardware specifications for the injector can be relaxed. As a result, it contributes to the reduction of the manufacturing cost of the engine system.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described in detail with reference to FIG.
FIG. 9 is a diagram illustrating an overall configuration of a pressure accumulation type fuel injection device according to the second embodiment.
The fuel injection device 1B of the second embodiment is different from the fuel injection device 1A shown in FIG. 1 in that (1) the fuel injection device 1B is provided in a high-pressure fuel supply passage 21 that supplies fuel to the injectors 5A arranged in each cylinder of the engine. In place of the differential pressure sensor S _dP for detecting the upstream / downstream differential pressure of the orifice 75, a pressure sensor (fuel supply passage pressure sensor) _SPs for detecting the pressure on the downstream side of the orifice 75 is provided, and (2 ) and point became ECU (control unit) 80B instead of ECU80A, is that changing the definition of the orifice differential pressure _{P OR} for calculating the orifice passing flow rate _{Q OR} of the fuel in (3) ECU80B.
The same components as those of the fuel injection device 1A according to the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

Pressure signal detected by four pressure sensors _{S Ps} as shown in FIG. 9 is input to ECU80B.
Then, ECU80B functions in the second embodiment is basically the same as ECU80A in the first embodiment (see FIG. 1), the signal used when calculating the orifice passing flow rate _{Q OR} of the fuel in ECU80B Is different from the case of the first embodiment.
In the first embodiment, by using the equation (1) has been calculated orifice passing flow rate Q _OR based on the orifice differential pressure P _OR, in the second embodiment, the orifice differential pressure in equation (1) the P _OR, replaced with the differential pressure (Pc-Ps) of the common rail pressure Pc of the pressure sensor _{S Pc} is detected, the downstream side pressure Ps of the orifice 75 the pressure sensor _{S Ps} is detected.

It is clear that the pressure on the upstream side of the orifice 75 of each high-pressure fuel supply passage 21 substantially coincides with the common rail pressure Pc. In the second embodiment, as in the first embodiment, the ECU 80B has the formula ( differential pressure orifice differential pressure _{P OR} in 1) (Pc-Ps) to replace easily accurate orifice passing flow rate _{Q OR,} ie calculate the actual fuel injection amount _{Q a} from the injector 5A for each cylinder. Then, ECU80B according to the second embodiment, like the ECU80A according to the first embodiment, by executing the correction procedure shown in FIG. 8, based on the target injection amount _{Q t} and the actual fuel injection quantity _{Q A} Te, can be corrected accurately _T i -Q characteristics.
Therefore injector 5A can be injected fuel accurately target injection amount Q _t into the cylinder of the engine (not shown), or increases the PM (particulate matter), preferably that the NOx and combustion noise or increasing Can be suppressed.

  As in the first embodiment, even if the requirements for hardware specifications such as dimensional tolerances for individual parts of the engine system are relaxed, the exhaust gas regulations can be easily cleared. In particular, the hardware specifications for the injector can be relaxed. As a result, it contributes to the reduction of the manufacturing cost of the engine system.

<< Third Embodiment >>
Next, a fuel injection device according to a third embodiment of the present invention will be described in detail with reference to FIG.
FIG. 10 is a diagram illustrating an overall configuration of a pressure accumulation fuel injection device according to the third embodiment.
The fuel injection device 1C of the third embodiment is different from the fuel injection device 1B shown in FIG. 9 in that (1) the ECU (control unit) 80C is used instead of the ECU 80B, and (2) the flow rate through the orifice. and that it uses a pressure sensor _{S Ps} instead of the pressure sensor _{S Pc} to calculate a Q _OR, is that changing the method of calculating the orifice passing flow rate _{Q OR} of the fuel in (3) ECU80C.
About the same structure as the fuel-injection apparatus 1B which concerns on 2nd Embodiment, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

Pressure signal detected by four pressure sensors _{S Ps} as shown in FIG. 10 is inputted to the ECU80C.
Then, ECU80C performs a filtering process for cutting a high frequency component of the pressure signal inputted from the pressure sensor _{S Ps} (high frequency noise).
Here the pressure Ps downstream of the orifice 75 that filtering will be referred to as pressure Ps _fil.
ECU80C according to the third embodiment, by utilizing the pressure _{Ps fil} was filtered to detect the pressure sensor _{S Ps} on the downstream side of the orifice 75 calculates the orifice passing flow rate _{Q OR.} Then, the calculated orifice passing flow rate _{Q OR,} and actual fuel injection amount _{Q A} from the injector 5A.

FIG. 11 is a flowchart showing a procedure for calculating the actual fuel injection amount in the third embodiment.
The procedure shown in FIG. 11, when the ECU80C executes the correction procedure shown in FIG. 8, and executed instead of step S1~ step S2, may be configured to calculate the actual fuel injection amount Q _A.
Hereinafter, mainly with reference to FIG. 11, ECU80C according to the third embodiment will be described the procedure for calculating the actual fuel injection quantity Q _A (appropriately with reference Figure 10).
The processing in steps S14~S17 shown in FIG. 11 is performed in a suitable tens μsec period of to sample the filtered pressure _{Ps fil} (sampling period), Delta] t to be described later, with its sampling period is there.

The ECU 80C checks whether or not the rising of the injection instruction signal has been detected (step S11), and if detected (step S11 → Yes), the control proceeds to step S12, and if not detected (step S11 → No). Then, control returns to step S11.
The rise of the injection instruction signal can be easily detected by, for example, differentiating the injection instruction signal with respect to time.

Then, the ECU 80C resets the initial value to Q _sum = 0.0 (step S12). Here, Q _sum corresponds to the orifice passage flow rate Q _OR calculated by time integration with respect to one fuel injection instruction signal.

ECU80C is detected by the pressure sensor _{S Ps,} the downstream side pressure _{Ps fil} orifices 75 after being filtered it is determined whether or not lower than the predetermined value _{P 0 [(Ps} fil _<P 0)? If the downstream pressure Ps _file falls _{below the} predetermined value P ₀ (step S13 → Yes), the control proceeds to step S14, and if not (step S13 → No), the control returns to step S13.

Here, the predetermined value P ₀ is a value obtained from the pressure signal detected by the pressure sensor _{SP Ps due} to high-frequency noise, for example, pressure pulsation caused by the filling operation of the high-pressure pump 3B, or the injector 5A of another cylinder performs an injection operation The pressure pulsation caused by the propagation of vibration and the pressure pulsation caused by the reflected wave after the injector 5A of the own cylinder performs the injection operation are removed by filtering, and the lower limit value of the vibration in the remaining pressure fluctuation is predetermined. to set the value _{P 0.} This value can be obtained by experiments or the like.

Then, the ECU 80C calculates a pressure decrease amount (P ₀ -Ps _fil ) from the predetermined value P ₀ to the pressure Ps _fil, and instead of the orifice differential pressure P _OR in the equation (1), the calculated pressure decrease amount (P ₀ -Ps _fil) by substituting calculates the orifice passing flow rate _{Q OR} (step S14).
At this time, the orifice passing flow Q _OR is fuel during the sampling period Δt is calculated as the flow rate Delta] Q _OR passing through the orifice 75.

Furthermore, ECU80C _{is, Q sum = Q sum + ΔQ} OR × Δt as (step S15), and integrating the orifice passing flow rate _{Q OR.}

The ECU 80C checks whether or not the falling of the fuel injection instruction signal has been detected (step S16), and if the falling of the injection instruction signal is detected (step S16 → Yes), the control proceeds to step S17.
On the other hand, it does not detect the falling of the injection command signal (step S16 → No), ECU80C the control returns to step S14, and repeats the accumulation of the orifice passing flow rate _{Q OR.}
The detection of the falling edge of the injection instruction signal can be easily detected by, for example, differentiating the injection instruction signal with respect to time.

ECU80C the downstream side pressure _{Ps fil} orifice 75 that is filtered to check whether an increase beyond a predetermined value _{P 0 [(Ps fil} ≧ _P 0)? (Step S17). When the downstream pressure _{Ps fil} is increased above a predetermined value _{P 0} (step S17 → Yes), ECU80C advances the control to step S18, otherwise (step S17 → No), ECU80C the control to step S14 return.

Then, ECU80C _is a _{Q sum} and the actual fuel injection quantity _{Q A} (step S18), and based on the calculated actual fuel injection amount _{Q A,} executes step S3 and subsequent correction procedure shown in FIG.

Note that after the third embodiments falling of the injection command signal of the fuel checks whether it has detected in the step S16, and detects the falling of the injection command signal, downstream pressure Ps _fil orifice 75 is predetermined While the control for detecting the timing of increased to a value P ₀ or more, be omitted step S16, and detects the timing at which the downstream pressure Ps _fil is increased above a predetermined value P _0, the passage of the orifice 75 of the fuel The end can be detected.

According to the third embodiment, it is possible to utilize the detection value of the pressure sensor S _Ps for detecting the pressure Ps downstream of the orifice 75, and calculates the actual fuel injection amount Q _A.
Further, only the pressure signal from the pressure sensor _{S Ps} for detecting the pressure downstream of the orifice 75, replacing the orifice differential pressure _{P OR} a predetermined value _{P 0} and the pressure difference between the pressure _{Ps fil (P 0 -Ps fil)} Based on the equation (1), the actual fuel injection amount Q _A of the fuel can be easily calculated for each cylinder with high accuracy. Then, as in the first embodiment and the second embodiment, ECU80C, based on the target injection amount _{Q t} and the actual fuel injection quantity _{Q A,} it makes it possible to correct accurately _T i -Q characteristics.
Therefore injector 5A can be injected fuel accurately target injection amount Q _t into the cylinder of the engine (not shown), or increases the PM (particulate matter), preferably that the NOx and combustion noise or increasing Can be suppressed.

  As in the first embodiment, even if the requirements for hardware specifications such as dimensional tolerances for individual parts of the engine system are relaxed, the exhaust gas regulations can be easily cleared. In particular, the hardware specifications for the injector can be relaxed. As a result, it contributes to the reduction of the manufacturing cost of the engine system.

<< Fourth Embodiment >>
Hereinafter, a fuel injection device according to a fourth embodiment of the present invention will be described in detail with reference to FIGS. 12 and 13.
FIG. 12 is a diagram showing the overall configuration of the pressure accumulation type fuel injection device of the fourth embodiment, and FIG. 13 is a back pressure type fuel injection used in the pressure accumulation type fuel injection device of the fourth embodiment. It is a conceptual lineblock diagram of a valve (injector).
The fuel injection device 1D according to the fourth embodiment differs from the first embodiment in the following points.
(1) An injector 5B having an actuator 6B that is a back pressure type fuel injection valve is used. (2) Along with this, a drain passage 9 is connected to the injector 5B provided in each cylinder, which are further connected to the return fuel pipe 73, and a flow rate adjustment in which a check valve 74 and an orifice 76 are connected in parallel. It is connected to a low-pressure fuel supply pipe 61 on the discharge side of the low-pressure pump 3A through a vessel. (3) The fuel injection device 1D of the fourth embodiment is electronically controlled by an ECU (control unit) 80D.
The same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

Next, the structure of the injector 5B of the fourth embodiment will be described with reference to FIGS. This injector 5B is a well-known one and is attached to each cylinder of the engine. The outline of the injector 5B will be described below.
As shown in FIG. 13, the injector 5B includes an injector body 13 having one or more fuel injection holes 10 formed at the tip, and a nozzle needle 14 slidably supported in the injector body 13. The piston 16 is connected to the upper end side of the nozzle needle 14 via a pressure pin 15 and includes a piston 16 that reciprocally moves integrally with the nozzle needle 14.

The injector body 13 includes a nozzle body 17 and a nozzle holder 19. An oil sump 20 is formed in the nozzle body 17 so that the high-pressure fuel is always filled around the nozzle needle 14. The oil reservoir 20 is always in communication with the common rail 4 through a fuel passage 25 and a high-pressure fuel supply passage 21 formed in the nozzle holder 19. The nozzle body 17 is fastened and fixed to the nozzle holder 19 by a retaining nut 22.
The nozzle holder 19 constitutes a cylinder in which a long hole 23 that slidably supports the piston 16 is formed in the longitudinal direction of the central portion. A back pressure chamber 7 that opens at the upper end surface of the nozzle holder 19 is formed between the upper end portion of the long hole 23 and the lower end surface of the first diaphragm forming member 11. A fuel passage 25 branched from the high-pressure fuel supply passage 21 in the nozzle holder 19 communicates with the back pressure chamber 7 via a communication passage 26 formed in the first throttle forming member 11.

  The nozzle needle 14 is disposed on the same axis as the central axis of the actuator 6 </ b> B composed of a two-way solenoid valve, and is slidably supported on the inner periphery of the nozzle body 17. When the nozzle is opened, the nozzle needle 14 is lifted up to form a fuel passage between the tip of the nozzle needle 14 and the nozzle body 17, and the oil reservoir 20 and the fuel injection hole 10 communicate with each other to provide fuel to the engine. A jet is made. When the nozzle is closed, the tip of the nozzle needle 14 is seated on the seat surface 17a of the nozzle body 17 and the injection of high-pressure fuel is terminated.

A coil spring 27 that urges the nozzle needle 14 in the valve closing direction is mounted between the large diameter portion of the pressure pin 15 and the nozzle holder 19. The piston 16 is disposed on the same axis as the central axis of the actuator 6 </ b> B, and is slidably supported on the inner peripheral surface of the long hole 23 of the nozzle holder 19.
As shown in FIG. 13, the actuator 6 </ b> B is slidable in the valve body 32, an iron core 33 disposed above the valve body 32, an electromagnetic coil 34 wound around a storage portion of the iron core 33, and the actuator body 6 </ b> B. And a coil spring 37 that urges the valve 35 in the valve closing direction. The valve body 32, the iron core 33, the electromagnetic coil 34, the valve 35, and the stopper 36 are a retaining nut (not shown) in a state where the lower end portion of the valve body 32 is in liquid-tight contact with the upper end portion of the nozzle holder 19 of the injector 5B. Thus, the nozzle holder 19 is fastened and fixed to the upper end surface.

  In the valve body 32, the first and second throttle forming members 11 and 12 are fitted in a liquid-tight manner in a recess 39 that is open to communicate with the back pressure chamber 7. A fuel chamber 40 having an inner diameter larger than that of the recess 39 is formed in the valve body 32. The fuel chamber 40 is connected to a return fuel pipe 73 communicating with the fuel tank 2 via a drain passage 9 provided in the valve body 32 or the like.

  The iron core 33 is magnetized when the electromagnetic coil 34 is energized. The valve 35 has a plate-shaped seal portion 42 on the distal end side and a rod-shaped portion 43 on the upper end side. The valve 35 is attracted to the magnetized iron core 33 and lifted up, and the rod-like portion 43 of the valve 35 is seated on the tip surface of the stopper 36. When energization of the electromagnetic coil 34 is stopped, the magnetic force attracting the valve 35 disappears, and the seal portion 42 of the valve 35 is applied to the upper end surface of the second diaphragm forming member 12 by the downward biasing force of the coil spring 37. Sit down.

  The first and second aperture forming members 11 and 12 are made of, for example, alloy steel such as SCM420 or carbon steel, and are formed in an annular plate shape centered on the same axis as the central axis of the valve 35 of the actuator 6B. ing. The first throttle forming member 11 and the second throttle forming member 12 are formed so that the orifices 51 and 52 have inner diameters smaller than the inner diameters of the fuel passage 25 and the communication passage 26. The orifice 51 is arranged with its central axis slightly shifted from the central axis of the first throttle forming member 11 toward the communication path 26, and the orifice 52 is formed on the same axis as the central axis of the second throttle forming member 12. . The orifice 51 restricts the cross-sectional area of the first passage that communicates the back pressure chamber 7 and the orifice 52. The orifice 52 restricts the cross-sectional area of the second passage that communicates the orifice 51 and the drain passage 9. The orifice 52 is a valve seat member having an inner diameter that is 1.4 to 1.6 times larger than the inner diameter of the orifice 51.

  The illustrated lower end side of the orifices 51 and 52 is formed so that the inner diameter on the back pressure chamber 7 side is increased. The outlet of the orifice 51 is disposed so as to face the tapered passage wall surface of the inlet of the orifice 52.

Next, a method for calculating the actual fuel injection amount Q _A for each cylinder of fuel in the ECU 80D will be described with reference to FIGS.
FIG. 14 is a diagram showing the time transition of the injection instruction signal for one cylinder and the fuel behavior in the high-pressure fuel supply passage, (a) is a diagram showing the output pattern of the injection instruction signal, and (b) is the actual value from the injector. The figure which shows the time transition of fuel injection quantity, (c) is a figure which shows the time transition of the flow rate through the orifice of fuel, (d) is a figure which shows the time transition of the pressure change of the upstream and downstream of the orifice.

In FIG. 14A, the fuel injection instruction signal is conceptually represented by one wide pulse, the rising start time of the injection instruction signal is t _S , and the falling start time of the injection instruction signal is t _E , and the falling completion time of the injection instruction signal is t _E ′.

Correspondingly, the fuel passage 25, the communication passage 26, the back pressure chamber 7, the orifices 51 and 52, the fuel chamber 40, and the like by the lift-up of the valve 35 (see FIG. 13) in the injector 5 B which is a back pressure type fuel injection valve. The back flow that returns to the low-pressure fuel supply pipe 61 through the drain passage 9 and the like starts at t _{SA as} shown by the curve b in FIG. The start of this backflow occurs slightly later than the rise t _S of the injection instruction signal.
Due to the occurrence of this backflow, the back pressure chamber 7 becomes lower than the pressure in the oil sump 20, the piston 16 is pulled upward, and the actual fuel injection becomes t _SB as shown by the curve a in FIG. Be started.

Then, at the falling timing t _E of the injection instruction signal, the coil spring 37 is stopped energization of the electromagnetic coil 34 (see FIG. 13) pushes down the valve 35 downward to close the flow path of the back flow, FIG. 14 As shown by curve b in (b), the backflow ends at _tEA . As a result, the pressure of the back pressure chamber 7 is balanced with the pressure of the oil sump 20, and the urging force of the coil spring 27 causes the nozzle needle 14 to move downward together with the piston 16 to be seated on the seat surface 17a. ), The actual fuel injection ends at t _{EB as} indicated by the curve a.

The amount of fuel passing through the orifice 75 (orifice passage flow rate Q _OR ) is delayed from the back flow start t _SA by the volume of the fuel passage 25 and the high-pressure fuel supply passage 21, as shown in FIG. It rises from t _S2. Similarly, the flow rate through the orifice returns to 0 at t _E2 after the completion of fuel injection by t _{EB corresponding} to the volume of the fuel passage 25 and the high-pressure fuel supply passage 21.

The pressure on the upstream and downstream sides of the orifice 75 corresponding to FIG. 14C is the differential pressure sensor even if the upstream pressure on the orifice varies due to the variation of the common rail pressure Pc, as shown in FIG. since S _dP enables detection orifice differential pressure _{P OR,} it can be calculated orifice passing flow rate _{Q OR} is. The area of the region indicated by the dot of the orifice passage flow rate _QOR shown in FIG. 14C is the back flow and the actual fuel injection amount Q _A shown in FIG. 14B in the case of the back pressure type injector 5B. It becomes the same as the total area of both.
Orifice passing flow rate Q _OR of the fuel from the orifice differential pressure P _OR can be easily calculated by the equation (1) as in the first embodiment described above.

ここで、Ｍ_Ｐは独立信号波形か、近接した複数の信号波形かを示すパラメータである。
そして、ＥＣＵ８０Ｄが図１４の（ａ）に示すように噴射指示信号を出力するとき、その出力パターンに応じて、独立信号波形か、近接した複数の信号波形かを判定し、更に信号波形面積Ａ_Ｐを演算して、式（４）により実噴射量換算係数γを設定する。
なお、インジェクタ５Ｂの開閉の応答速度が速い場合、前記した独立信号波形か、近接した複数の信号波形かの区別は不要である。 Then, the ECU80D, previously, in accordance with the output pattern of the injection instruction signal of the fuel, among the calculated orifice passing flow rate Q _OR, actual fuel injection amount Q _A, which is the amount of fuel injected actually from the injector 5B The actual injection amount conversion coefficient γ, which is a coefficient value indicating the ratio, is stored in the storage unit 81 of the ECU 80D, for example, in the form of a correlation equation of signal parameters.
The actual injection amount conversion coefficient γ corresponding to the output pattern of the injection instruction signal of the fuel, for example, a signal parameter the signal waveform area A _P as the correlation equation shown in equation (4), the time or a predetermined distance in the case of independent injection instruction signal off, in one signal waveform area independent injection instruction signal reflecting the width of the injection time T _i, also, a plurality of injection instruction signal temporal proximity within a predetermined distance In this case, the following equation (4) is set according to the total signal waveform area of the plurality of injection instruction signals.

Here, _MP is a parameter indicating whether an independent signal waveform or a plurality of adjacent signal waveforms.
Then, when the ECU 80D outputs the injection instruction signal as shown in FIG. 14A, it is determined whether it is an independent signal waveform or a plurality of adjacent signal waveforms according to the output pattern, and further, the signal waveform area A _P is calculated and the actual injection amount conversion coefficient γ is set according to equation (4).
When the response speed of opening and closing of the injector 5B is fast, it is not necessary to distinguish between the above-described independent signal waveform and a plurality of adjacent signal waveforms.

Then, by multiplying the actual injection amount conversion coefficient γ to the calculated orifice passing flow rate Q _OR, it calculates the actual fuel injection amount Q _A.

Therefore, the ECU 80D according to the fourth embodiment can execute the correction procedure shown in FIG. 8 as in the first embodiment, and even in the fuel injection device 1D including the back pressure injector 5B, ECU80D, based on the target injection amount _{Q t} and the actual fuel injection quantity _{Q a,} makes it possible to correct accurately _T i -Q characteristics.
Therefore injector 5B it can inject the fuel accurately target injection amount Q _t into the cylinder of the engine (not shown), as in the first embodiment, or increased PM (particulate matter) is, NOx and combustion An increase in noise can be suitably suppressed.

Further, according to the fourth embodiment, it is easy to accurately manufacture the diameter of the opening of the orifice 75 (see FIG. 12), and the orifice differential pressure between the upstream side and the downstream side of the orifice 75. P _OR becomes larger than the differential pressure between the upstream side and the downstream side of the venturi-type narrow portion, and the orifice passing flow rate Q _OR can be easily calculated from the orifice differential pressure P _OR by the differential pressure sensor S _dP by the equation (1). Can be calculated.
Then, to calculate the orifice passing flow rate Q _OR from the orifice differential pressure P _OR, by multiplying the actual injection amount conversion coefficient γ to the orifice passing flow Q _OR, is possible to accurately calculate the actual fuel injection amount Q _A of the injector 5B it can.

Thus, the manufacturing tolerances of the injector 5B, the waveform of the same injection instruction signal, also the variation of the orifice passing flow Q _OR is the sum of the back flow and the actual fuel injection quantity Q _A is present between the injector 5B, Since the actual fuel injection amount Q _A reflecting the influence of the manufacturing tolerance can be calculated, for example, the ECU 80D (see FIG. 12) accurately calculates the T based on the calculated actual fuel injection amount Q _A and the target injection amount Q _{t. The i-} Q characteristic can be corrected.
As a result, the injector 5B (see FIG. 12) can be injected fuel accurately target injection amount Q _t into the cylinder of the engine (not shown), or an increase of an engine (not shown) PM (particulate matter) is, NOx And increase in combustion noise can be suitably suppressed.

As in the first embodiment, be varied orifice upstream side pressure in accordance with the variation of the common rail pressure Pc, (see FIG. 12) ECU80D is the orifice differential pressure _{P OR} is detected by the differential pressure sensor _{S dP} Further, the orifice passage flow rate _QOR can be calculated.
ECU80D Therefore, even if the common rail pressure Pc varies, the actual fuel injection amount Q _A can be calculated accurately.
Therefore, even when the common rail pressure Pc fluctuates, the ECU 80D can correct the T _i -Q characteristic with high accuracy.

In addition, the fuel injection from the injector 5B is actually “pilot injection” for the purposes of reducing PM (particulate matter), NOx and combustion noise, and activating the catalyst by raising exhaust gas temperature and supplying a reducing agent. "," Pre (injection) "," After (injection) "and" Post (injection) "multi-stage injection.
And, in such a multi-stage injection, the respective cylinders can not be ensured target injection amount Q _t, it may not be clear limits for exhaust gas of the engine.

For example, time degradation such as the seat surface 17a of the injector 5B (see FIG. 13) is wear caused by changes in the characteristics of the injector 5B used for a long time, the actual fuel injection amount Q _A prescribed amount can no longer be ensured even if, ECU80D by executing the correction procedure, in response to changes in the characteristics of the injector 5B can be corrected T _i -Q characteristics, it can be ensured target injection amount Q _t.

  As a result, it is easy to clear the exhaust gas regulations even if the requirements for hardware specifications such as dimensional tolerances on individual parts of the engine system are relaxed. In particular, the hardware specifications for the injector can be relaxed. As a result, it contributes to the reduction of the manufacturing cost of the engine system.

In the fourth embodiment, the γ actual injection amount conversion coefficient used when calculating the actual fuel injection amount Q _A from the orifice passing flow Q _OR was variable, it may be approximately fixed value.

<< Fifth Embodiment >>
Next, a fuel injection device according to a fifth embodiment of the present invention will be described in detail with reference to FIG.
FIG. 15 is a diagram illustrating an overall configuration of a pressure accumulation type fuel injection device according to a fifth embodiment.
The fuel injection device 1E of the fifth embodiment is different from the fuel injection device 1D shown in FIG. 12 in that (1) the fuel injection device 1E is provided in a high-pressure fuel supply passage 21 that supplies fuel to the injectors 5B arranged in each cylinder of the engine. instead of the differential pressure sensor _{S dP} for detecting an upstream-downstream differential pressure of the orifice 75, a point having a pressure sensor _{S Ps} for detecting the pressure downstream of the orifice 75, (2) instead of ECU (control ECU80D and point became part) 80E, is that changing the definition of the orifice differential pressure _{P OR} for calculating the orifice passing flow rate _{Q OR} of the fuel in (3) ECU80E.
In other words, the fifth embodiment is adapted to the injector 5B by replacing the injector 5A (see FIG. 9), which is a direct-acting fuel injection valve, with the injector 5B, which is a back pressure fuel injection valve, in the second embodiment. Thus, the second embodiment is modified.
The same components as those of the fuel injection device 1D according to the fourth embodiment are denoted by the same reference numerals, and redundant description is omitted.

Pressure signal detected by four pressure sensors _{S Ps} as shown in FIG. 15 is input to ECU80E.
The function of the ECU80E in the fifth embodiment is basically the same as ECU80D in the fourth embodiment, execution signal is of the fourth using an orifice passing flow _{Q OR} of the fuel when calculated in ECU80E Different from the case of form.
In the fourth embodiment, the above-mentioned has been calculated orifice passing flow rate Q _OR by the formula (1), in the fifth embodiment, the orifice differential pressure P _OR in the formula (1), the pressure sensor S _Pc is detected The pressure is replaced with a differential pressure (Pc−Ps) between the common rail pressure Pc and the downstream pressure Ps of the orifice 75 detected by the pressure sensor _SPs .

It is clear that the pressure on the upstream side of the orifice 75 of each high-pressure fuel supply passage 21 substantially matches the common rail pressure Pc. In the fifth embodiment, as in the fourth embodiment, the ECU 80E has the formula ( easily accurate orifice passing flow rate _{Q OR} replaces the orifice differential pressure _{P OR} to the differential pressure (Pc-Ps) in 1), can be calculated for each cylinder. Furthermore ECU80E is an actual injection amount conversion coefficient γ is calculated in accordance with the output pattern of the injection instruction signal by multiplying the orifice passing flow rate Q _OR, it calculates the actual fuel injection amount Q _A of each of the cylinders. Then, ECU80E according to the fifth embodiment, like the ECU80D in the fourth embodiment, by executing the correction procedure shown in FIG. 8, based on the target injection amount _{Q t} and the actual fuel injection quantity _{Q A} The T _i -Q characteristic can be corrected with high accuracy.
Therefore injector 5B it can inject the fuel accurately target injection amount Q _t into the cylinder of the engine (not shown), as in the second embodiment, or increased PM (particulate matter) is, NOx and combustion An increase in noise can be suitably suppressed.
Note that the actual injection amount conversion coefficient γ may be stored in the storage unit 81 of the ECU 80E, for example, in the form of a correlation equation of signal parameters, as in the fourth embodiment.

  As in the second embodiment, even if the requirements for hardware specifications such as dimensional tolerances for individual parts of the engine system are relaxed, the exhaust gas regulations can be easily cleared. In particular, the hardware specifications for the injector can be relaxed. As a result, it contributes to the reduction of the manufacturing cost of the engine system.

<< Sixth Embodiment >>
Next, a fuel injection device according to a sixth embodiment of the present invention will be described in detail with reference to FIG.
FIG. 16 is a diagram illustrating an overall configuration of a pressure accumulation type fuel injection device according to a sixth embodiment.
The fuel injection device 1F of the sixth embodiment is different from the fuel injection device 1E shown in FIG. 15 in that (1) an ECU (control unit) 80F is used instead of the ECU 80E, and (2) an orifice passage flow rate Q. and that it uses a pressure sensor _{S Ps} instead of the pressure sensor _{S Pc} to calculate the _OR, is that changing the method of calculating the orifice passing flow rate _{Q OR} of the fuel in (3) ECU80F.
In other words, the sixth embodiment is adapted to the injector 5B by replacing the injector 5A (see FIG. 10), which is a direct-acting fuel injection valve, with the injector 5B, which is a back pressure fuel injection valve, in the third embodiment. Thus, the third embodiment is modified.
The same components as those of the fuel injection device 1E according to the fifth embodiment are denoted by the same reference numerals, and redundant description is omitted.

Pressure signal detected by four pressure sensors _{S Ps} as shown in FIG. 16 is input to ECU80F.
Then, ECU80F performs a filtering process for cutting the high-frequency noise included in the pressure signal inputted from the pressure sensor S _Ps.
Here the pressure Ps downstream of the orifice 75 that filtering will be referred to as pressure Ps _fil.
ECU80F according to the sixth embodiment calculates the orifice passing flow rate _{Q OR} by using the pressure _{Ps fil} was filtered to detect the pressure sensor _{S Ps} on the downstream side of the orifice 75, the further orifice passing flow rate _{Q OR} based calculates an actual fuel injection quantity Q _a and.

Then, only by a signal from the pressure sensor S _Ps on the downstream side of the orifice 75 in the sixth embodiment while referring to FIG. 17, calculates the orifice passing flow rate Q _OR of the fuel, further based on the orifice passing flow rate Q _{OR A} method for calculating the actual fuel injection amount QA will be described.
FIG. 17 is a flowchart showing a procedure for calculating the actual fuel injection amount in the sixth embodiment.
The procedure shown in FIG. 17, when the ECU80F executes the correction procedure shown in FIG. 8, and executed instead of step S1~ step S2, may be configured to calculate the actual fuel injection amount Q _A.
Hereinafter, mainly with reference to FIG. 17, ECU80F is a procedure for calculating the actual fuel injection quantity _{Q A} (appropriately with reference Figure 16).

  The process of step S21 to step S27 in the flowchart shown in FIG. 17 is the same as the procedure of step S11 to step S17 in the flowchart shown in FIG. However, “ECU 80C” and “injector 5A” in the explanatory text of the flowchart in FIG. 11 are read as “ECU 80F” and “Injector 5B”, respectively.

After executing up to step S27, the ECU 80F refers to the storage unit 81 based on a preset injection instruction signal and acquires the actual injection amount conversion coefficient γ (step S28).
Note that the actual injection amount conversion coefficient γ may be stored in the storage unit 81 of the ECU 80F, for example, in the form of a correlation equation of signal parameters, as in the fourth embodiment.

Next, the ECU 80F multiplies Q _sum by an actual injection amount conversion coefficient γ to obtain an actual fuel injection amount Q _A (step S29).
Then, ECU80F, based on the actual fuel injection quantity _{Q A} calculated, executes step S3 and subsequent correction procedure shown in FIG.

According to the sixth embodiment, it is possible to utilize the detection value of the pressure sensor S _Ps for detecting the pressure Ps downstream of the orifice 75, and calculates the orifice passing flow rate Q _OR.
Further, only the pressure signal from the pressure sensor _{S Ps} for detecting the pressure downstream of the orifice 75, replacing the orifice differential pressure _{P OR} a predetermined value _{P 0} and the pressure difference between the pressure _{Ps fil (P 0 -Ps fil)} easily orifice passing flow rate Q _OR highly accurate fuel based on equation (1) can be calculated for each cylinder. Then, as in the fourth embodiment, and fifth embodiment, based on the calculated orifice passing flow rate Q _OR, the actual fuel injection amount Q _A can be calculated accurately.

Therefore, ECU80F is based and the target injection amount _{Q t} calculated for the actual fuel injection amount _{Q A,} makes it possible to correct accurately _T i -Q characteristics.
The injector 5B can inject the fuel accurately target injection amount Q _t into the cylinder of the engine (not shown), as in the third embodiment, or increased PM (particulate matter) is, NOx Ya It can suppress suitably that a combustion noise increases.

  As in the third embodiment, the exhaust gas regulations can be easily cleared even if the requirements for hardware specifications such as dimensional tolerances on individual parts of the engine system are relaxed. In particular, the hardware specifications for the injector can be relaxed. As a result, it contributes to the reduction of the manufacturing cost of the engine system.

  Thus, in the fourth to sixth embodiments, the injector 5B is a back pressure type fuel injection valve as shown in FIG. 13, and the actuator 6B drives the valve 35 by the electromagnetic coil 34. Although it is a type which controls the pressure of the back pressure chamber 7, it is not limited to it. For example, an injector having a configuration in which a control valve having a three-way valve structure is operated using a stack of piezo elements to control the pressure in the back pressure chamber 7 disposed above the nozzle needle 14 to stop fuel injection and injection may be used. .

As described above, in the case where the orifice 75 is provided near the common rail 4 of the high pressure fuel supply passage 21 for supplying high pressure fuel to the direct acting injector 5A provided in the fuel injection device 1A shown in FIG. Based on the differential pressure between the upstream side and the downstream side (orifice differential pressure P _OR ), the orifice passage flow rate Q _OR of the fuel passing through the orifice 75 can be easily calculated.
Then, even if in the common rail pressure Pc varies, small influence of the orifice passing flow rate Q _OR calculated based on the orifice differential pressure P _OR, can be calculated accurately orifice passing flow rate Q _OR.

If the injector 5A direct acting, the actual fuel injection amount _{Q A} from equal to the orifice passing flow rate _{Q OR,} ECU80A, by detecting the accurate orifice differential pressure _{P OR,} accurate actual fuel injection amount _{Q A} Can be calculated.
Therefore, by detecting the orifice differential pressure _{P OR} orifice 75, ECU80A would be accurately calculate the actual fuel injection amount _{Q A} injected from the injector 5A.
Then, ECU80A is based and the target injection amount _{Q t} calculated for the actual fuel injection amount _{Q A,} makes it possible to correct accurately _T i -Q characteristics.

Therefore, for example, even if the actual fuel injection amount Q _A changes due to changes in the characteristics of the injector 5A due to changes in the environment and operating conditions, deterioration of the injector 5A with time, etc., the ECU 80A does not change the actual fuel injection amount Q. _The T _i -Q characteristic can be corrected so as to absorb the change of _A. Based on the corrected T _i -Q characteristic, the target injection time T _t corresponding to the target injection amount Q _t can be set.
This fact, ECU80A, even if the characteristics of the injector 5A has changed fuel injection amount Q with respect to changes injection time T _i, excess and deficiency of the actual fuel injection amount Q _A of the respective cylinders of the engine (not shown) Can be suppressed. Therefore, there is an excellent effect that it is possible to suitably suppress an increase in PM (particulate matter) of an engine (not shown) or an increase in NOx and combustion noise.

Further, for example, by manufacturing tolerances, even if there are variations in the actual fuel injection amount _{Q A} of the injector 5A, ECU80A can correct the _T i -Q characteristics so as to correspond to the injector 5A, the injector absorbs variations in the actual fuel injection amount Q _a of each 5A, it is possible to obtain a fuel injection device 1A which can be stably injected actual fuel injection amount Q _a of the target injection amount Q _t the same amount.

Further, it provided in the fuel injection device 1D shown in FIG. 12, also the high-pressure fuel to the common rail 4 side of the high pressure fuel supply passage 21 for supplying to the injector 5B of the back pressure though the configuration is equipped with orifices 75, the orifice passing flow rate Q _OR Based on this, since the actual fuel injection amount Q _A of the injector 5B can be calculated, the same effect as the case where the direct-acting injector 5A (see FIG. 1) is provided can be obtained.

  As described above, according to the present invention, it is possible to suitably suppress the occurrence of excess or deficiency in the actual fuel injection amount regardless of the type of the injector, increasing the PM (particulate matter) of the engine, And an increase in combustion noise can be suitably suppressed.

  In the first to sixth embodiments, the injectors 5A and 5B have been described as performing fuel injection directly into the combustion chamber of each cylinder. However, the present invention is not limited to this. In the present invention, the injectors 5A and 5B are configured to inject fuel toward a sub chamber (premix space) formed adjacent to the combustion chamber of each cylinder, and to inject fuel toward the intake port of each cylinder. Includes configurations to perform. Moreover, also in such a structure, the effect in 1st Embodiment to 6th Embodiment is acquired similarly.

It is the figure which showed the whole structure of the pressure accumulation type fuel-injection apparatus of 1st Embodiment. It is a conceptual lineblock diagram of a direct-acting type fuel injection valve (injector) used for a pressure accumulation type fuel injection device of a 1st embodiment. It is a figure which shows the time transition of the output pattern of the injection instruction | indication signal with respect to one cylinder, and the fuel behavior in a high pressure fuel supply path, (a) is a figure which shows the output pattern of an injection instruction | indication signal, (b) is the actual fuel from an injector The figure which shows the time transition of the injection quantity, (c) is the figure which shows the time transition of the orifice passage flow rate of fuel, (d) is the figure which shows the time transition of the pressure change of the upstream and downstream of the orifice. (A) is _a diagram showing an example of a characteristic curve _{f Ti} showing a _T i -Q characteristics, (b) are diagrams showing a _T i -Q characteristic corresponding to the common rail pressure. (A) is a characteristic line common rail pressure indicates T _i -Q characteristics when the representative pressure value Pc ₁ and the representative pressure value Pc ₂ figure, a diagram showing a (b) is adjacent characteristic line correlation equation is there. It is a conceptual diagram for correcting the characteristic line T i _-Q characteristics. The T i _-Q characteristics is a conceptual diagram is corrected based on the correlation equation. ECU is a flowchart showing a procedure for correcting the _T i -Q characteristics. It is the figure which showed the whole structure of the pressure accumulation type fuel-injection apparatus of 2nd Embodiment. It is the figure which showed the whole structure of the pressure accumulation type fuel-injection apparatus of 3rd Embodiment. It is a flowchart which shows the procedure which calculates actual fuel injection quantity in 3rd Embodiment. It is the figure which showed the whole structure of the pressure accumulation type fuel-injection apparatus of 4th Embodiment. It is a conceptual lineblock diagram of a back pressure type fuel injection valve (injector) used for a pressure accumulation type fuel injection device of a 4th embodiment. It is a figure which shows the time transition of the injection instruction | indication signal with respect to one cylinder and the fuel behavior in a high voltage | pressure fuel supply path, (a) is a figure which shows the output pattern of an injection instruction | indication signal, (b) is the actual fuel injection amount from an injector. The figure which shows a time transition, (c) is a figure which shows the time transition of the orifice passage flow rate of a fuel, (d) is a figure which shows the time transition of the pressure change of the upstream and downstream of an orifice. It is the figure which showed the whole structure of the pressure accumulation type fuel injection apparatus of 5th Embodiment. It is the figure which showed the whole structure of the pressure accumulation type fuel-injection apparatus of 6th Embodiment. It is a flowchart which shows the procedure which calculates actual fuel injection quantity in 6th Embodiment.

Explanation of symbols

1A, 1B, 1C, 1D, 1E, 1F Fuel injection device 2 Fuel tank 3A Low pressure pump (fuel pump)
3B High pressure pump (fuel pump)
4 Common rail (fuel accumulator)
5A, 5B injector (fuel injection valve)
21 High-pressure fuel supply passage (fuel supply passage)
73 Return fuel piping 75 Orifice 80A, 80B, 80C, 80D, 80E, 80F ECU (control part)
81 Storage unit Q Fuel injection amount S _dP differential pressure sensor S _Pc pressure sensor (pressure accumulation unit pressure sensor)
_SPs pressure sensor (fuel supply passage pressure sensor)
_Ti injection time

Claims (12)

A fuel accumulator that stores fuel sent out by the fuel pump in an accumulator state;
A fuel injection valve for supplying fuel supplied through a fuel supply passage branched from the fuel accumulator to each cylinder of the internal combustion engine to a combustion chamber of each cylinder of the internal combustion engine;
An accumulator pressure sensor for detecting the pressure of the fuel accumulator;
A control unit for setting a target injection amount of fuel injected by the fuel injection valve;
A fuel injection device comprising: a storage unit that stores, as data, a T _i -Q characteristic indicating a correlation between a fuel injection amount (Q) of the fuel injection valve and an injection time (T _i );
The T _i -Q characteristic is obtained by performing regression analysis on data obtained by discretely measuring the correlation between the fuel injection amount (Q) and the injection time (T _i ) at a representative pressure value representative of the pressure of the fuel accumulator. It is shown by the characteristic line expressed by the polynomial
The control unit obtains a target injection time corresponding to the target injection amount from the characteristic line based on the pressure of the fuel storage unit detected by the pressure storage unit pressure sensor and the target injection amount. Fuel injection device.   2. The fuel injection device according to claim 1, wherein in a region where the fuel injection amount (Q) is equal to or greater than a predetermined boundary value, the polynomial representing the characteristic line is a linear polynomial. The T _i -Q characteristic is indicated by a plurality of characteristic lines based on a correlation between the fuel injection amount (Q) measured for each of the plurality of representative pressure values and the injection time (T _i ),
The fuel injection device according to claim 1, wherein a correlation expression indicating a correlation between the polynomials representing the characteristic lines adjacent to each other is set. When the pressure of the fuel accumulator detected by the accumulator pressure sensor is a value between the two representative pressure values,
The control unit obtains the target injection time corresponding to the pressure of the fuel accumulating unit by interpolating the two characteristic lines indicating the T _i -Q characteristics at the two representative pressure values. The fuel injection device according to claim 3. An orifice disposed in the fuel supply passage;
A differential pressure sensor that detects a differential pressure upstream and downstream of the orifice in the fuel supply passage,
The fuel injection valve is configured to supply the entire amount of fuel supplied through the fuel supply passage during fuel injection to the combustion chamber of each cylinder,
The control unit calculates an actual fuel injection amount injected by the fuel injection valve during the target injection time based on a signal from the differential pressure sensor,
5. The fuel injection device according to claim 1, wherein when the actual fuel injection amount is different from the target injection amount, the T _i -Q characteristic is corrected. 6. An orifice disposed in the fuel supply passage;
A fuel supply passage pressure sensor for detecting a pressure downstream of the orifice in the fuel supply passage;
The fuel injection valve is configured to supply the entire amount of fuel supplied through the fuel supply passage during fuel injection to the combustion chamber of each cylinder,
The control unit calculates a differential pressure between the upstream side and the downstream side of the orifice based on a signal from the pressure accumulating unit pressure sensor and a signal from the fuel supply passage pressure sensor, and the fuel injection is performed at the target injection time. Calculating the actual fuel injection amount injected by the valve based on the differential pressure;
5. The fuel injection device according to claim 1, wherein when the actual fuel injection amount is different from the target injection amount, the T _i -Q characteristic is corrected. 6. An orifice disposed in the fuel supply passage;
A fuel supply passage pressure sensor for detecting a pressure downstream of the orifice in the fuel supply passage;
The fuel injection valve is configured to supply the entire amount of fuel supplied through the fuel supply passage during fuel injection to the combustion chamber of each cylinder,
The control unit detects an amount of pressure drop associated with fuel injection from the fuel injection valve based on a signal from the fuel supply passage pressure sensor, and the fuel injected by the fuel injection valve during the target injection time An injection amount is calculated based on the pressure drop amount,
Wherein when the actual fuel injection amount is different from the target injection amount, a fuel injection device according to any one of claims 1 to 4, characterized in that to correct the T _i -Q characteristics. An orifice disposed in the fuel supply passage;
A differential pressure sensor that detects a differential pressure upstream and downstream of the orifice in the fuel supply passage,
The fuel injection valve has a structure in which a part of the fuel supplied through the fuel supply passage at the time of fuel injection is returned to the fuel pipe and discharged to the low pressure portion of the fuel supply system,
The control unit calculates a flow rate of fuel passing through the orifice during the target injection time based on a signal from the differential pressure sensor, and does not return to the return fuel pipe out of the flow rate through the orifice. The actual fuel injection amount actually supplied to the combustion chamber of each cylinder is calculated based on the orifice passage flow rate and a predetermined coefficient value,
Wherein when the actual fuel injection amount is different from the target injection amount, a fuel injection device according to any one of claims 1 to 4, characterized in that to correct the T _i -Q characteristics. An orifice disposed in the fuel supply passage;
A fuel supply passage pressure sensor for detecting a pressure downstream of the orifice in the fuel supply passage;
The fuel injection valve has a structure in which a part of the fuel supplied through the fuel supply passage at the time of fuel injection is returned to the fuel pipe and discharged to the low pressure portion of the fuel supply system,
The control unit calculates a differential pressure between the upstream side and the downstream side of the orifice based on a signal from the pressure accumulating unit pressure sensor and a signal from the fuel supply passage pressure sensor, and sets the orifice at the target injection time. The flow rate of the fuel passing through the orifice is calculated based on the differential pressure, and the actual fuel injection amount actually supplied to the combustion chamber of each cylinder without returning to the return fuel pipe out of the flow rate through the orifice. , Based on the flow rate through the orifice and a predetermined coefficient value,
Wherein when the actual fuel injection amount is different from the target injection amount, a fuel injection device according to any one of claims 1 to 4, characterized in that to correct the T _i -Q characteristics. An orifice disposed in the fuel supply passage;
A fuel supply passage pressure sensor for detecting a pressure downstream of the orifice in the fuel supply passage;
The fuel injection valve has a structure in which a part of the fuel supplied through the fuel supply passage at the time of fuel injection is returned to the fuel pipe and discharged to the low pressure portion of the fuel supply system,
The control unit detects an amount of pressure drop due to fuel injection from the fuel injection valve based on a signal from the fuel supply passage pressure sensor, and the flow rate of fuel passing through the orifice during the target injection time Is calculated based on the pressure drop amount, and the actual fuel injection amount actually supplied to the combustion chamber of each cylinder without returning to the return fuel pipe out of the orifice passage flow rate is calculated as the orifice passage flow rate and Calculate based on a predetermined coefficient value,
Wherein when the actual fuel injection amount is different from the target injection amount, a fuel injection device according to any one of claims 1 to 4, characterized in that to correct the T _i -Q characteristics. The controller is
6. The T _i -Q characteristic is corrected by correcting the characteristic line used for obtaining the target injection time when the actual fuel injection amount is different from the target injection amount. The fuel injection device according to claim 10. When the T _i -Q characteristic is indicated by a plurality of the characteristic lines, and a correlation equation indicating the correlation of the polynomial representing the characteristic lines adjacent to each other is set,
The controller is
When the actual fuel injection amount is different from the target injection amount, the characteristic line used for obtaining the target injection time is corrected, and the characteristic lines adjacent to each other are sequentially corrected by the correlation equation, and the T The fuel injection device according to any one of claims 5 to 10, wherein the _i- Q characteristic is corrected.

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