DE102021108873A1 - Fuel injection control device for internal combustion engine - Google Patents

Abstract

A timing unit determines a number of excitations of a drive unit at an injection occasion and sets an excitation time (Tq) in each stage and an interval time (TINT) between excitations to perform fuel injection at a maximum injection rate in the intermediate stroke state in an injection period in which the excitation is carried out. An excitation control unit excites the drive unit based on the excitation time in each stage and the set interval time. An injection amount acquisition unit acquires an actual injection amount, which is an actual value, in one-stage excitation in which excitation is performed in one stage and / or two-stage excitation in which excitation is performed in two stages, on an injection occasion is an injection amount at each of the excitations. A characteristic adjustment unit calculates an adjustment amount of the injection characteristic data based on the actual injection amount at each energization. The time setting unit sets the excitation time by using the adjustment amount.

Description

TECHNICAL AREA

The present disclosure relates to a fuel injection control device for an internal combustion engine.

BACKGROUND

A fuel injection control device energizes a fuel injection device to cause a valve body to lift, thereby opening an injection hole and performing fuel injection. A known fuel injection device, which has a so-called flying needle structure, is configured to place a valve body in an intermediate lift state to perform fuel injection. This fuel injector does not bring the valve body into contact with an upper limit stopper. Therefore, the fuel injection device is advantageous in reducing an injection amount deviation due to an impact of the valve body and advantageous in reducing the injection amount deviation due to a deviation in a position of the upper limit stopper caused by individual differences and aging.

Furthermore, Patent Document 1 discloses a method for multiple excitation and de-excitation during an injection opportunity or an injection process while the valve body is held in an intermediate stroke state. In this way, Patent Document 1 enables a large amount of fuel to be injected while suppressing the enlargement of the fuel injection device. With this structure, after the first excitation is switched off, the second excitation is initiated before the valve body reaches the valve-closing position. In this way, fuel injection continues during the first excitation and the second excitation.

PATENT LITERATURE

PATENT LITERATURE 1

US-2020-0063694 A

In the technique of Patent Literature 1, however, it is conceivable that an error occurs in the injection amount when the energization and de-energization are performed multiple times while the valve body is kept in the intermediate stroke state in one injection opportunity. It is therefore believed that there is room for technical improvement.

SHORT VERSION

The present disclosure has been made in view of the above problems, and it is an object of the present disclosure to provide a fuel injection control device for an internal combustion engine that is configured to properly perform fuel injection control.

A fuel injection control device for an internal combustion engine according to the present disclosure is applied to a fuel injection system. The fuel injection system includes a fuel injector having a drive unit configured to be driven when energized and a valve body configured to open an injection hole in response to driving the drive unit. The fuel injection device is configured to change an injection amount depending on an energization timing of the drive unit and to set an intermediate lift state in which a lift amount of the valve body is a predetermined intermediate lift amount to generate a maximum injection amount.

The fuel injection control device is configured to determine an energization time corresponding to the injection amount and energize the drive unit in accordance with the energization time by using injection characteristic data showing a relationship between the energization time and the injection amount.

The fuel injection control apparatus includes: a timing setting unit configured to determine a number of excitations of the drive unit at an injection occasion and to set an excitation time in each stage and an interval time between the excitations in order to inject fuel at the maximum injection rate in the intermediate stroke state in an injection period perform, in which the excitation is carried out; an excitation control unit configured to excite the drive unit based on the excitation time in each stage and the interval time set by the time setting unit; an injection amount acquisition unit configured to acquire, on an injection occasion, an actual injection amount that is an actual value of an injection amount at each of the excitations; and a characteristic adjustment unit configured to calculate an adjustment amount of the injection characteristic data based on the actual injection amount acquired by the injection amount acquisition unit at each energization. The timing unit is configured to adjust the excitation time by the Using the adjustment amount calculated by the characteristic adjustment unit.

In the fuel injection system having the fuel injection device configured above, the drive unit is energized to open the injection hole by the valve body lift accompanying the drive of the drive unit to perform fuel injection. In this case, the injection amount changes by the energization time of the drive unit, and the maximum injection amount is generated by keeping the valve body stroke in the intermediate stroke state. In a fuel injection device having a so-called flying needle structure that injects fuel while the valve body is in the intermediate stroke, the valve body is not brought into contact with the upper limit stopper. In this way, the fuel injection device has the advantage that the deviation in the injection quantity due to the bouncing of the valve body is reduced.

The arrangement configured above is configured to determine a number of excitations of the drive unit at one injection occasion and to set an excitation time in each stage and an interval time between the excitations in order to perform fuel injection at the maximum injection rate in the intermediate stroke state in one injection period at which the excitement is carried out. Further, the arrangement configured above is designed so that the drive unit is excited by the excitation time and the interval time of each stage. In this case, the valve body lift amount is repeatedly increased and decreased by a plurality of divided excitations in one fuel injection, so that the valve body is maintained in a desired intermediate lift state without expanding the intermediate lift area of the fuel injector. In addition, during the energization in each stage, the injection with the maximum injection amount can be continuously performed, the injection amount can be linearized, and the fuel injection can be performed with high accuracy.

In a case where the fuel injection is performed by the multi-stage excitation on an injection occasion, it is desirable that the linearity of the injection amount with respect to the excitation time is maintained regardless of the number of the energization stages. When at least one-stage excitation and two-stage excitation are performed at one injection occasion, the actual injection amount, that is, the actual injection amount at each of these excitations is obtained. Further, the adjustment amount of the injection characteristic data is calculated based on the actual injection amount in each of these excitations. Then, when the adjustment amount of the injection characteristic data is calculated, the energization time is adjusted by using the adjustment amount. In this way, even if the number of energization stages is changed at one injection occasion, fuel injection can be properly performed every injection occasion. As a result, the control of the fuel injection can be implemented properly, i.e. optimally.

Figure list

• 1 ist ein Konfigurationsdiagramm, das eine Übersicht über ein Kraftstoffeinspritzsystem zeigt;
• 2 ist eine Schnittansicht, die den inneren Aufbau einer Kraftstoffeinspritzvorrichtung zeigt;
• 3 ist ein Zeitdiagramm, das eine Reihe von Prozessen der Kraftstoffeinspritzung zeigt;
• 4 umfasst (a) eine Ansicht, die eine Beziehung zwischen einem Kraftstoffdruck und einer Erregungszeit zeigt, und (b) eine Ansicht, die eine Beziehung zwischen dem Kraftstoffdruck und einer Intervallzeit zeigt;
• 5 ist ein erklärendes Zeitdiagramm, das eine Übersicht über die Einstellung der Erregungszeit und der Intervallzeit zeigt;
• 6 ist eine Ansicht, die eine Beziehung zwischen dem Kraftstoffdruck und einem Korrekturwert C zeigt;
• 7 ist ein Flussdiagramm, das einen Prozess einer Kraftstoffeinspritzungssteuerung zeigt;
• 8 ist eine Ansicht, die eine Beziehung zwischen dem Kraftstoffdruck und den Schwellenwerten Th1 bis Th3 zeigt;
• 9 ist eine Ansicht, die eine Beziehung zwischen der Erregungszeit und einer Einspritzmenge zeigt;
• 10 ist eine Ansicht, die eine Beziehung zwischen der Erregungszeit und einer Einspritzmenge zeigt;
• 11 ist ein erklärendes Zeitdiagramm, das die Kennlinien-Anpassung der Einspritzung an jedem Anpassungspunkt zeigt;
• 12 ist ein Zeitdiagramm, das einen Übergang eines Hubbetrags einer Düsennadel zeigt; und
• 13 ist ein Flussdiagramm, das einen Ablauf eines Kennlinien-Anpassungsablaufs zeigt.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:

• 1 Fig. 13 is a configuration diagram showing an outline of a fuel injection system;
• 2 Fig. 13 is a sectional view showing the internal structure of a fuel injection device;
• 3 Fig. 13 is a timing chart showing a series of processes of fuel injection;
• 4th includes (a) a view showing a relationship between fuel pressure and energization time, and (b) a view showing a relationship between fuel pressure and interval time;
• 5 Fig. 13 is an explanatory time chart showing an outline of setting of the excitation time and the interval time;
• 6th Fig. 13 is a view showing a relationship between fuel pressure and a correction value C;
• 7th Fig. 13 is a flowchart showing a process of fuel injection control;
• 8th Fig. 13 is a view showing a relationship between the fuel pressure and the threshold values Th1 to Th3;
• 9 Fig. 13 is a view showing a relationship between energization time and an injection amount;
• 10 Fig. 13 is a view showing a relationship between energization time and an injection amount;
• 11th Fig. 13 is an explanatory time chart showing the injection characteristic adjustment at each adjustment point;
• 12th Fig. 13 is a time chart showing a transition of a lift amount of a nozzle needle; and
• 13th Fig. 13 is a flowchart showing a procedure of a characteristic adjusting process.

DETAILED DESCRIPTION

In the following, embodiments will be described with reference to the drawings. The present embodiment is a fuel injection control device that controls fuel injection performed by a fuel injection device in a common rail fuel injection system (dynamic pressure fuel injection system) such as an in-vehicle diesel engine.

In 1 is in an internal combustion engine for each cylinder of a 4-cylinder diesel engine (hereinafter referred to as machine 10 referred to) a fuel injector 11th arranged. These fuel injectors 11th are with a common rail 12th (Manifold) connected, which is common to the cylinders. To the common rail 12th is a high pressure pump 13th connected as a fuel pump. When the high pressure pump 13th is driven, the fuel pressure increases, and high-pressure fuel having a pressure corresponding to an injection pressure is continuously in the common rail 12th accumulated. The high pressure pump 13th is driven when the machine is 10 rotates, and repeatedly sucks fuel and discharges the fuel in synchronism with the rotation of the engine. The high pressure pump 13th is at its fuel inlet section with an electromagnetically driven suction metering valve (SCV) 13a fitted. Via the suction valve 13a is done with the help of a feed pump 14th from a fuel tank 15th Delivered low-pressure fuel into a fuel chamber of the high-pressure pump 13th sucked.

The common rail 12th is with a pressure sensor 16 equipped with the pressure of the fuel (fuel pressure) in the common rail 12th as the pressure of the fuel injector 11th Detected fuel supplied. It should be noted that the pressure sensor 16 at different positions in each fuel injector 11th from the common rail fuel outlet 12th up to an injection port 33 (please refer 2 ) the fuel injector 11th can be provided. In particular, the pressure sensor 16 in each fuel injector 11th be provided in a high pressure fuel channel through which the high pressure fuel flows.

One ECU 20th is an electronic control unit that incorporates a well-known microcomputer 21 (Microcomputer) having a CPU and various memories (RAM, ROM, etc.) and performs various controls by executing a control program stored in the ROM. The microcomputer 21 sequentially receives detection signals from various sensors such as a speed sensor that detects an engine speed, an accelerator device sensor that detects an accelerator device, and a vehicle speed sensor that detects a vehicle speed, in addition to a detection signal of the pressure sensor 16 , as described above. The microcomputer 21 determines an injection amount and an injection timing as a fuel injection mode based on engine operation information such as an engine speed and an accelerator device, and controls those with the fuel injection device 11th performed fuel injection accordingly. The fuel injection control is performed to control the fuel injection from the fuel injection device 11th to control the combustion chamber in each cylinder.

In the ECU 20th generated by the microcomputer 21 an excitation pulse as an excitation command signal and outputs the excitation pulse to a drive circuit 22nd the end. As is well known, the control circuit 22nd a high voltage supply with a high voltage and a low voltage supply with a low voltage. At the beginning of the excitation, which is associated with the rise of the excitation pulse, the control circuit sets 22nd a high voltage to the drive unit (electric actuator described later 60 ) to the fuel injector 11th open at high speed. The control circuit then switches 22nd converts the applied voltage from high voltage to low voltage to the fuel injector 11th in an open valve state.

The ECU also provides 20th a setpoint or target value for the fuel pressure in the common rail 12th based on the operational information of the machine. At the same time, the ECU performs 20th performs feedback control so that the actual fuel pressure coincides with the target fuel pressure based on a deviation between the target fuel pressure and the actual fuel pressure (actual fuel pressure).

The following is the structure of the fuel injection device 11th with reference to 2 described. In 2 the vertical direction coincides with the axial direction of the fuel injector 11th and the lower side in the figure is the tip end side of the fuel injector 11th .

In the fuel injector 11th is a solid plate 40 integral in one body 31 intended. A jet needle 32 as the valve body is on the tip side of the fixed plate 40 housed in a state that allows them to move back and forth. Multiple injection ports 33 are at one tip of the body 31 educated. When the tip of the nozzle needle 32 with a seat section 31a of the body 31 comes into contact, the injection port 33 closed and fuel injection is stopped. Furthermore, the injection port 33 opened when the tip portion of the nozzle needle 32 from the seat section 31a is disconnected and fuel injection is performed.

In the body 31 and the fixed plate 40 is a high pressure channel 34 formed of the fixed plate 40 penetrates. The high pressure fuel duct 34 is provided in such an area that the high-pressure fuel channel 34 from a peripheral portion of the nozzle needle 32 to the tip end portion of the fuel injector 11th , ie the injection port 33 , extends. The one from the common rail 12th High pressure fuel is supplied through the high pressure channel 34 to the injection port 33 guided.

A tubular cylinder 35 is on a tip surface (the lower end surface in the figure) of the fixed plate 40 attached. The top of the nozzle needle 32 is sliding in the cylinder 35 used. The jet needle 32 is through one on the tip side of the cylinder 35 provided spring 36 pressed in a valve closing direction. Above the nozzle needle 32 and in the cylinder 35 there is a pressure control chamber 37 . The pressure control chamber 37 is configured to be filled with high pressure fuel. When the pressure control chamber 37 is filled with high pressure fuel, the high pressure fuel holds the nozzle needle 32 in a closed state.

The fixed plate 40 is with an inflow duct 41 for high pressure fuel to flow into the pressure control chamber 37 and an outflow channel 42 to flow out fuel from the pressure control chamber 37 educated. The inflow duct 41 is as a branch from the high pressure channel 34 and in a downstream portion thereof (ie, a portion leading to the pressure control chamber 37 leads) an orifice is formed that limits the fuel flow rate. Furthermore, is in the downstream section of the outflow channel 42 (ie in the section leading to a low pressure chamber described later 64 leads) an opening is formed which limits the fuel flow rate.

A disk-shaped movable plate 50 is in the pressure control chamber 37 arranged. The moving plate 50 is arranged to face a lower surface of the fixed plate 40 and is configured to be in the pressure control chamber 37 moved in the vertical direction shown in the figure. The moving plate 50 is with a connecting channel 51 formed, the outflow channel 42 with the pressure control chamber 37 connects. In the downstream section of the connecting duct 51 an aperture is formed that limits the fuel flow. The moving plate 50 closes the outlet section of the inflow channel 41 in a state in which it is in contact with the fixed plate 40 stands. The moving plate 50 however, maintains communication between the pressure control chamber 37 and the outflow channel 42 through the opening of the connecting channel 51 upright. In the pressure control chamber 37 is a feather 38 provided that the movable plate 50 against the solid plate 40 presses.

The outside diameter of the moving plate 50 is smaller than the inner diameter of the cylinder 35 . Therefore, a gap is formed between the outer peripheral surface of the movable plate 50 and the inner peripheral surface of the cylinder 35 . So if the moving plate 50 from the fixed plate 40 is separated, the high-pressure fuel flows in the inflow channel 41 through the gap on the outer periphery of the movable plate 50 into the pressure control chamber 37 (more precisely, in the upper surface of the nozzle needle 32 ).

There is also an electric actuator 60 as a drive unit inside the housing 31 on the top of the solid plate 40 housed opposite side. The electric actuator 60 includes a solenoid coil 61 , a control valve 62 as a valve element and a spring 63 as a drive element. The control valve 62 is configured so that it is in the low pressure chamber 64 moved in the vertical direction shown in the figure. When the solenoid coil 61 is not energized, the control valve 62 by the excitation of the pen 63 held in a state in which it is against the fixed plate 40 is pressed and the fuel injector 11th is kept in a closed state.

Further, when the solenoid coil 61 is energized, the control valve 62 against the excitation of the pen 63 from the fixed plate 40 separated. If then the control valve 62 moves, high pressure fuel flows in the pressure control chamber 37 through the outflow channel 42 the fixed plate 40 and the connection channel 51 the moving plate 50 into the low pressure chamber 64 the end. As a result, the nozzle needle moves 32 to the side of the valve opening. In this way, the injection port 33 opened and fuel injection started. At this point, the nozzle needle 32 raised from the closed position of the valve so that the injection quantity (i.e. the injection quantity per unit of time) gradually increasing. Then, when the lift amount of the needle reaches a predetermined lift amount at which the opening area of the seat portion 31a (ie the gap area between the seat section 31a and the nozzle needle 32 ) and the total cross-sectional area of the injection opening 33 become equal, the injection amount becomes the maximum. After the lift amount of the needle reaches a predetermined lift amount, the state of the maximum injection amount is maintained.

In the case of the fuel injector 11th the present embodiment comes the nozzle needle 32 not with the upper limit stop element (e.g. the movable plate 50 ) on the valve opening side when the lift amount of the needle reaches the predetermined lift amount at which the maximum injection rate is reached. Therefore, the fuel injection is performed in an intermediate lift state (floating state). The fuel injector 11th has a so-called flying needle structure that performs fuel injection with a maximum injection amount in this state when the lift amount of the needle reaches the predetermined intermediate lift amount.

If then the energization of the solenoid coil 61 is stopped and the control valve 62 due to the compressive force of the spring 63 in contact with the fixed plate 40 comes, becomes the outflow channel 42 closed, and in this state, the movable plate 50 through the high pressure fuel from the inflow duct 41 pressed down. As a result, high pressure fuel flows into the pressure control chamber 37 . This will make the nozzle needle 32 pressed down on the valve closing side, and the injection port 33 returns to the closed state.

The electric actuator 60 can use a drive unit with a piezo element. That is, a piezo-driven fuel injection device as a fuel injection device 11th can be used.

In the configuration in which the fuel injection is performed using the fuel injection device 11th done with a floating needle assembly, the nozzle needle becomes 32 not brought into contact with the upper limit stop element. This configuration is advantageous in reducing the injection amount deviation due to the bouncing of the nozzle needle 32 and reduce the deviation in the injection amount due to the deviation in the position of the upper limit stopper due to individual differences and aging. On the other hand, there is concern that the amount of fuel injected at an injection occasion may be limited. In this configuration, the injection duration is due to the restriction of the nozzle needle 32 that does not reach the upper limit stop element is limited. If, on the other hand, the injection duration is to be lengthened, the stroke range must be extended from the position of the valve closure to the upper limit stop element, which increases the size of the fuel injection device 11th can lead.

Therefore, in the present embodiment, the number of times of energization at one injection occasion of the fuel injection device becomes 11th certainly. In addition, an excitation time Tq in each stage and an interval time TINT between the excitations in an injection period when the excitation is performed are set so that the fuel injection is performed at the maximum injection rate in the intermediate stroke state. Then the electric actuator 60 excited by the excitation with the excitation time Tq and the interval time TINT as set for each stage.

3 Fig. 13 is an explanatory timing chart showing behavior when the nozzle needle 32 the fuel injector 11th is increased by an intermediate lift amount before reaching a lift upper limit Lmax, and the fuel injection is performed in this state. 3 shows the behavior when the fuel injector 11th is excited in two successive stages during the excitation periods. Fuel injection is performed by the excitation in two successive stages. Here, the excitation time by the first-stage excitation is Tq1 and the excitation time by the second-stage excitation is Tq2. The arousal time between first stage excitation and second stage excitation is TINT.

In 3 the first-stage energizing pulse is raised at time t1, and fuel injection is started with the start of energization. At this time, a high voltage is applied to the solenoid coil to start energizing 61 applied, causing a high current to be supplied to the nozzle needle 32 the fuel injector 11th open at high speed. The applied voltage is then switched from high voltage to low voltage. In this way, a holding current is fed to the nozzle needle 32 holds in the open state of the valve.

After the start of excitation at time t1, the lift amount (needle lift amount) of the nozzle needle increases 32 gradually to. At this time, the amount of lift of the nozzle needle increases 32 proportional to the duration of the excitation. Furthermore, the injection rate increases when the nozzle needle 32 is raised. Then, at time t2, the amount of lift of the needle reaches a predetermined amount of lift at which the opening area of the seat portion 31a and the total cross-sectional area of the injection port 33 are the same size. This makes the injection rate the maximum injection rate. In 3 is the lift amount of the needle at which the injection amount is the maximum injection amount (ie, the lift amount of the needle at which the opening area of the seat portion is 31a and the total cross-sectional area of the injection port 33 are equal), a lower stroke limit Lmin. After time t2, the state of the maximum injection rate is maintained.

At time t3, when the predetermined excitation time Tq1 has passed since the excitation was started, the excitation is temporarily stopped because the excitation pulse falls. In this way, the stroke amount of the needle changes from increasing to decreasing. At this time, the amount of lift of the needle changes from the rising to the falling state without the upper limit Lmax of the fuel injection device 11th to reach.

After time t3, the amount of lift of the needle goes into the falling state in proportion to the duration of the excitation interruption. It should be noted that, in this state, the stroke amount of the needle is larger than the stroke lower limit Lmin. Therefore, the state in which the maximum injection rate is held is maintained even after the first-stage energization is stopped. That is, the range from the lower stroke limit Lmin to the upper stroke limit Lmax is the intermediate stroke range Rf, and the needle stroke amount is within the intermediate stroke range Rf. In this way, the state of the maximum injection rate is maintained.

Thereafter, at time t4, when the predetermined interval time TINT has elapsed since the energization was stopped, the second-stage energizing pulse is increased and the amount of lift of the needle changes to increase again. At this time, at time t4, the solenoid coil is energized 61 resumed before the stroke amount of the needle reaches the stroke lower limit Lmin. At the time of the second stage excitation, as with the first stage excitation, the high voltage is applied at the beginning of the excitation and the subsequent change to the low voltage application. After the excitation is restarted at time t4, the amount of lift of the needle increases again in proportion to the duration of the excitation, and the state of the maximum injection amount is maintained.

At time t5 when the predetermined excitation time Tq2 has elapsed from the start of the excitation in the second stage, the excitation is stopped as the excitation pulse falls, and the stroke amount of the needle changes from increasing to decreasing. Thereafter, the stroke amount of the needle falls below the stroke lower limit Lmin at time t6 and becomes zero at time t7. Fuel injection is thus completed.

In the above-described one-time fuel injection, the fuel injection is started with the start of the first-stage energization, and the injection rate reaches the maximum injection rate. Thereafter, in the period until the injection amount starts to decrease with the end of the excitation in the second stage (the period from t2 to t6), the lift amount of the needle is kept within the intermediate lift range Rf between Lmin and Lmax. This will keep the injection rate at the maximum injection rate during this period. This configuration enables the injection duration of the fuel injector 11th to extend during the intermediate stroke of the nozzle needle 32 is retained. Thus, this configuration enables the injection amount to be increased to a desired level.

Although not shown, fuel injection may be performed with energization in three consecutive stages or energization in more than three consecutive stages. Similar to the description above, the configuration can keep the lift amount of the needle in the energization in each stage within the intermediate lift amount Rf, and hence perform the fuel injection continuously at the maximum injection rate.

A specific method of setting the energization time Tq and the interval time TINT in each stage in the fuel injection control that performs fuel injection with multi-stage energization will be described below. Here, for example, a three-stage excitation mode is described in which fuel injection is carried out with three-stage excitation.

The ECU 20th calculates the required injection amount Qr in the fuel injection at this time and the energization time Tr (total energization time) of the fuel injection device 11th corresponding to the required injection amount Qr before setting the energizing time Tq and the interval time TINT for each stage. The required injection amount Qr is the total injection amount for one combustion. Note that in a case where the main injection and the pilot injection preceding the main injection are performed in one combustion stroke, the required injection amount Qr to be divided may be the injection amount of the main injection. As is known, the required injection amount Qr is determined based on an operating condition of the engine, e.g. B. an engine speed and an engine load, and the fuel pressure (rail pressure) is calculated. The energization time Tr is obtained by time converting the required injection amount Qr calculated as a function of the engine speed.

Then the ECU performs 20th perform multi-stage divided excitation when the required injection amount QR (or excitation time Tr) is equal to or greater than a predetermined value. The ECU 20th sets the excitation time Tq for each stage and the interval time TINT. For example, in a case where the three-stage divided excitation is performed, the excitation times Tq1, Tq2, Tq3 in the first to third stages and the interval times TINT1, TINT2 are set.

The first-stage excitation Tq1 is set as an excitation time from the start of the first excitation until a predetermined amount of lift is reached in the intermediate lift range Rf (Lmin to Lmax). In other words, the first stage excitation Tq1 is set as the excitation time for lifting the needle from the zero stroke position (valve closed position) to a predetermined position close to the upper stroke limit Lmax.

Further, the energization times Tq2 and Tq3 in the second and third stages are set as energization times that make it possible to increase the amount of lift of the needle in the intermediate lift range Rf. More specifically, the energization time Tq2 in the second stage is set as the energization time required for the needle to be raised from a predetermined position near the lower stroke limit Lmin to a predetermined position near the upper stroke limit Lmax in the intermediate stroke range Rf. The third stage excitation time Tq3 is a time required for the final stage excitation in the present fuel injection, and is set as the remaining excitation time after the first stage excitation and the second stage excitation.

The excitation time Tq is set in each stage so that the position of the needle stroke does not reach the upper stroke limit Lmax after the excitation has started in the stage. With this configuration, the number of times of excitation is increased so that the injection amount can be increased at one time while the state in which the nozzle needle is in 32 the upper limit stop elements are not reached, is retained.

The lifting speed (valve opening speed) of the nozzle needle 32 changes depending on the fuel pressure. Therefore, the energization times Tq1 to Tq3 are preferably set in the stages according to the fuel pressure. For example, the energization times Tq1 to Tq3 in the stages can be set with reference to those in (a) in FIG 4th depicted relationship can be set. (a) in 4th FIG. 13 shows a relationship in which the energization time Tq1 to Tq3 is shortened in each stage as the fuel pressure becomes higher. The jet needle 32 lifts itself out of the zero stroke position (valve closed position) during the first stage excitation. Therefore, the excitation time Tq1 in the first stage is made longer than the excitation times Tq2 and Tq3 in the second and third stages.

Further, the energization times TINT1 and TINT2 between the energizations in the stages are set as the energization interruption time that allows the intermediate lift amount to change within the intermediate lift range Rf to decrease. More specifically, the interval times TINT1 and TINT2 are set as the energization interruption time required for lowering the needle from a predetermined position near the upper limit of the stroke Lmax to a predetermined position near the lower limit of the stroke Lmin within the intermediate stroke range Rf.

Each interval time TINT is set as a time during which the stroke position of the needle does not fall below the stroke lower limit Lmin after the excitation in the stage is stopped. In this case, in the intermediate stroke range Rf (Lmin to Lmax) is that from the injection opening 33 constant amount of fuel ejected per unit of time, so that the valve closing speed of the nozzle needle 32 becomes constant during the excitation interruption time. Assuming that the amount of lift of the nozzle needle when the excitation is stopped L1 and the closing speed of the needle valve is Vnc, the interval time TINT can be calculated as a time satisfying the relationship of the following equation (1). $$\text{TINT}=\left(\text{L.}1-\text{Lmin}\right)/\text{Vnc}$$

In this case, the interval time TINT is set as a constant value when the needle stroke position when the excitation is stopped in the first stage and the needle stroke position when the excitation is started in the second stage are constant.

If the interval time TINT is too long, the position of the needle stroke falls below the lower stroke limit Lmin. In this case, arises on the seat section 31a in the fuel injector 11th a flow restriction so that the injection quantity falls below the maximum injection quantity. As a result, linearity of the control of the injection amount with respect to the energization time is deteriorated. In this connection, the interval time TINT is determined to be the time obtained with the above equation (1) as the maximum time or less, thereby maintaining the linearity of the control of the injection amount with respect to the energization time.

The lowering speed (valve closing speed) of the nozzle needle 32 changes depending on the fuel pressure. Therefore, the interval time becomes TINT 1 and TINT2 are preferably set according to the fuel pressure. For example, the interval time TINT1 and TINT2 can be set with reference to the in (b) in 4th depicted relationship can be set. (am 4th Fig. 13 shows a relationship in which, as the fuel pressure increases, the energization suspension time becomes shorter in the interval times TINT1 and TINT2.

The excitation time Tr (total excitation time) and the excitation time Tq1, Tq2, Tq3 in the stage may be in the relationship of the following equation (2). $$\text{Tr}=\text{<figure-callout id="1" label="Tq" filenames="DE102021108873A1\_0009.png" state="{{state}}">Tq</figure-callout>}1+\text{Tq}2+\text{<figure-callout id="3" label="Tq" filenames="DE102021108873A1\_0008.png" state="{{state}}">Tq</figure-callout>}3$$

In this case, as described above, the energization time Tq1 in the first stage is set as the energization time required for the needle lift from the zero lift position (valve closing position) to the predetermined position near the lift upper limit Lmax. The energization time Tq2 in the second stage is set as the energization time required for the needle stroke from a predetermined position near the stroke lower limit Lmin to a predetermined position near the stroke upper limit Lmax. Then, the energization time Tq3 in the third stage is set with the relationship of the following equation (3). $$\text{<figure-callout id="3" label="Tq" filenames="DE102021108873A1\_0008.png" state="{{state}}">Tq</figure-callout>}3=\text{Tr}-\left(\text{<figure-callout id="1" label="Tq" filenames="DE102021108873A1\_0009.png" state="{{state}}">Tq</figure-callout>}1+\text{Tq}2\right)$$

The setting of the excitation time Tq1 to Tq3 in the stage is additionally described below.

5 Fig. 13 is a timing chart showing the excitation in the one-stage excitation mode in which fuel injection is performed with one-stage excitation and in the three-stage excitation mode in which fuel injection is performed with three-stage split excitations. In 5 the change in the amount of lift of the needle in the one-step excitation mode is shown by an alternate long and short dashed line, and the change in the amount of lift of the needle in the three-step energization mode is shown by a solid line. Similar to the three-stage excitation mode, it is also assumed in the single-stage excitation mode that the injection amount becomes the maximum injection amount in the range in which the stroke amount of the needle becomes greater than the stroke lower limit Lmin, and that the fuel injection is carried out while the needle is floating, without the nozzle needle 32 the upper limit stop element has been reached. In the 5 The illustrated stroke upper limit Lmax is a position of the stroke upper limit in a case where multi-stage divided excitation is performed. It is assumed that the upper stroke limit in the case of single-stage excitation is on the higher stroke side than position Lmax.

First, the mode of one-step excitation will be described. When the one-stage excitation is performed, the excitation is continuously performed during the period from the start of the excitation to the lapse of the excitation time Tr. In this case, the amount of lift of the needle increases substantially in proportion to the time from time t11, which is the start time of excitation, and the amount of lift of the needle decreases substantially in proportion to the time after the excitation is stopped. The injection rate starts to increase at time t11 and is maintained at the maximum injection rate during the period from time t12 to t13. Then the injection rate goes to point in time 114 back to zero.

In contrast, in the case where the three-stage excitation is performed in the three-stage excitation mode, the excitations for three times and the excitation interruptions for two times are alternately performed. In this case, after time t11, which is the start time of excitation, the amount of lift of the needle increases substantially in proportion to time, and the amount of lift of the needle substantially decreases in proportion to time by repeating the excitation and the excitation interruption .

The period between time tx1 when the first-stage excitation is completed and time tx2 when third-stage excitation in the three-stage excitation mode is completed is a period TD. At the period TD, the excitation by the one-stage excitation and the excitation by the three-stage excitation are compared.

In this case, “TD1” in the period TD is a period corresponding to the excitation (elevation period) in the one-stage excitation. This corresponds to the sum of the second-stage excitation Tq2 and the third-stage excitation Tq3. Further, “TD2” in the period TD is a period corresponding to the suspending time of the excitation (lowering) in the one-stage excitation. This corresponds to the sum of the first interval time TINT1 and the second interval time TINT2.

According to this relationship, in both the one-stage excitation mode and the three-stage excitation mode, the end of time tx2 of the period TD is the time at which the excitations in the excitation time Tq1, Tq2, Tq3 for the three levels and the excitation interruptions in the interval time TINT1, TINT2 for two times Are completed. Therefore, the lift amount is (lift position of the nozzle needle 32 ) at the end of the excitation time tx2 in the single-stage excitation mode and in the three-stage excitation mode the same. Thereafter, time t13 at which the injection amount falls below the maximum injection amount and time t14 at which the injection amount becomes zero are also identical in the one-stage energization mode and the three-stage energization mode.

This gives the relationship between the excitation time Tr (total excitation time) and the excitation time Tq1, Tq2, Tq3 of the stage as defined in the above equation (2).

It should be noted that it is in actual operation of the fuel injector 11th to a delay in response of the nozzle needle 32 can come when the nozzle needle 32 at the beginning of the excitation in the second or subsequent stages changes from lowering to raising. Therefore, it is desirable to set the energizing time Tq and the interval time TINT in the stage in consideration of the response delay. In this case, the third stage energization time Tq3 can be adjusted by the following equation (4) using a correction value C for the response delay. $$\text{<figure-callout id="3" label="Tq" filenames="DE102021108873A1\_0008.png" state="{{state}}">Tq</figure-callout>}3=\text{Tr}-\left(\text{<figure-callout id="1" label="Tq" filenames="DE102021108873A1\_0009.png" state="{{state}}">Tq</figure-callout>}1+\text{Tq}2\right)+\text{C.}$$

By correcting the response delay as described above, the linearity of the response of the injection amount with respect to the excitation time Tq is maintained. The correction value C can be calculated based on the fuel pressure with reference to FIG 6th can be calculated.

To correct the response delay of the nozzle needle 32 the interval time TINT can be corrected instead of correcting the excitation time Tq of the second or subsequent stages. In this case, the interval time TINT can be corrected so that it is reduced in consideration of the response delay.

7th Fig. 13 is a flowchart showing a process of fuel injection control performed by energization of the fuel injection device 11th is performed. This process is done by the microcomputer 21 the ECU 20th executed repeatedly in a predetermined cycle.

In 7th will be in step S11 the required injection amount Qr is calculated based on the operating condition of the engine, such as the engine speed and load, and the fuel pressure (rail pressure). In the next step S12 the energization time Tr is calculated by time converting the required injection amount Qr according to the engine speed. At this time, the energization time Tr is calculated based on the required injection amount QR by using the injection characteristic data showing the relationship between the energization time and the injection amount.

After that, in step S13 determines whether the required injection amount Qr is smaller than the predetermined threshold value Th1, a threshold value for switching between performing fuel injection this time in the one-stage excitation or in the multi-stage excitation of two or more stages. In step S13 For example, the energization time Tr can be used as the determination parameter in place of the required injection amount Qr.

When the required injection amount Qr is smaller than the threshold amount Th1, the procedure goes to step S14 above. In step S14 it is determined that the fuel injection is performed in the one-stage energization mode this time. Then the following step S15 the excitation pulse for one-step excitation based on that in step S12 calculated excitation time Tr, and in the subsequent step S16 the excitation pulse is output. In this case the microcomputer gives 21 a one-step excitation pulse to the drive circuit 22nd off, and the control circuit 22nd energizes and de-energizes the fuel injector 11th corresponding to the rising time and the falling time of the excitation pulse.

When the required injection amount Qr is not less than the threshold amount Th1, the procedure goes to step S21 above. In step S21 it is determined that the fuel injection is performed in the multi-stage energization mode this time.

In the next step S22 will the The number of stages of multi-stage excitation is determined according to the required injection amount Qr. At this time, one or more threshold values larger than the above-mentioned threshold value Th1 are set, and the number of stages of multi-stage excitation is determined according to the result of the comparison between the required injection amount QR and each threshold value. For example, in addition to the threshold value Th1, the threshold values Th2 and Th3 are also established (Th1 <Th2 <Th3). When the required injection amount Qr is in the range of Th1 to Th2, the two-stage energization is stopped. When the required injection amount Qr is in the range of Th2 to Th3, the three-stage energization mode is set. When the required injection amount Qr Th3 or more, the four-stage energization mode becomes. The number of stages of multi-stage energization may be 4 or more.

The threshold values Th1 to Th3 are the maximum injection amounts when the fuel injection is performed in the stage energization mode. That is, when the required injection amount Qr reaches the threshold value Th1 or more, the required injection amount Qr exceeds the maximum injection amount in the one-stage excitation, and therefore the two-stage excitation is stopped. When the required injection amount Qr reaches the threshold value Th2 or more, the required injection amount Qr exceeds the maximum injection amount in the two-stage energization mode, and therefore the three-stage energization mode is set in three or more stages.

The threshold values Th1 to Th3 can be variably set in accordance with the fuel pressure. For example, the threshold values Th1 to Th3 are set to larger values the higher the fuel pressure is, as in FIG 8th shown.

After that, in step S23 the excitation time Tq and the pause time TINT in each stage of the multi-stage excitation based on that in step S12 calculated excitation time Tr. With two-stage excitation, two excitation times Tq1 and Tq2 and an interval time TINT are set. In the three-stage excitation mode, three excitation times Tq1, Tq2, Tq3 and two pause times TINT1, TINT2 are set. The same is true for arousal through four or more stages.

The excitation time Tq and the pause time TINT can be set in each stage based on the fuel pressure. At this time, the energization time Tq in each stage can be determined based on the fuel pressure with reference to those in (a) in FIG 4th depicted relationship can be set. Further, each interval time TINT can be determined based on the fuel pressure with reference to the in (b) in FIG 4th depicted relationship can be set.

In the case of multi-stage excitation, it is conceivable that the fuel pressure is lowered at the time of the excitation in the last stage due to the fuel injection caused by the first-stage excitation. The difference in fuel pressure affects the stroke of the nozzle needle 32 the end. Therefore, in the energization of the last stage, the energization time Tq in each stage can be set so that the fuel pressure is lower than that in the energization in the previous stage. That is, assuming that the first-stage excitation fuel pressure is PA, the second-stage excitation fuel pressure is PA - ΔP1, and the third-stage excitation fuel pressure is PA - (ΔP1 + ΔP2). ΔP1 is a fuel pressure decrease caused by the injection due to the first-stage excitation, and ΔP2 is a fuel pressure decrease caused by the fuel injection due to the second-stage excitation. The fuel pressure PA can be a detection pressure of the pressure sensor 16 when the required injection amount Qr is calculated at that time.

After that, in step S24 is set a correction value C corresponding to the response delay in lifting the needle that occurs at the start of the excitation in the second or subsequent stages, and at least one of the excitation time Tq and the interval time TINT in the second or subsequent stages is corresponding to Correction value C set. In this case, the excitation time Tq can be corrected by the correction value C in the output stage. In addition, the excitation time Tq in an intermediate stage other than the final stage can be corrected by the correction value C, or the interval time TINT can be corrected by the correction value C.

The correction value C can be set based on the fuel pressure. At this time, the correction value C can be adjusted based on the fuel pressure with reference to FIG 6th depicted relationship can be set. Note that the correction value C may be a predetermined fixed value. The correction value C may be a value that is common to each fuel injection device 11th taking into account an individual difference of the fuel injector 11th each cylinder is determined.

After that, in step S25 generated multiple excitation pulses according to the excitation mode. At this time, in the two-stage excitation mode, excitation pulses are generated in two successive stages based on the excitation times Tq1 and Tq2 and the interval time TINT. In the three-stage excitation mode, based on the excitation times Tq1 to Tq3 and the pause times TINT1 and TINT2, excitation pulses are generated in successive three-stages. The same is true for the excitation mode with four or more levels.

After that, in step S26 , the excitation pulse is output. In this case the microcomputer gives 21 Excitation pulses of the stages to the control circuit 22nd off, and the control circuit 22nd energizes and de-energizes the fuel injector 11th corresponding to the rising time and the falling time of each excitation pulse.

Further, in the present embodiment, in the case where multi-stage shared excitation is performed, the Injection quantity characteristic curve adapted in order to reduce a deviation in the injection quantity during fuel injections of different excitation levels. In this case the ECU performs 20th performs one-stage excitation in which the excitation is performed in one stage on one injection occasion; and performs two-stage excitation in which the excitation is performed in two stages on one injection opportunity, and obtains the actual injection amount at each excitation. Based on the actual injection amount at each energization, the ECU calculates 20th then an adjustment amount of injection characteristic data representing the relationship between the energization time and the injection amount. In the fuel injection control, the energization time is determined based on the required injection amount at that time using the injection map data.

More precisely, show how in 9 As shown, the injection characteristic data shows the relationship between the energization time and the injection amount. X1 is an excitation time range in which one-stage excitation can be performed. X2 is an excitation time range in which two-stage excitation can be performed. In the excitation time range X1 are two adjustment points P1 and P2 Are defined. Two adjustment points P3 and P4 are in the range of the excitation time X2 Are defined. Any of these adjustment points P1 until P4 is defined as a coordinate point composed of a predetermined excitation time and an injection amount on a basic characteristic curve that represents the injection characteristic curve data. The adjustment points P1 and P2 correspond to a “first adjustment point”, and the adjustment points P3 and P4 correspond to a "second adjustment point". In the adjustment point P1 the energization time Tq1 is 1 and the injection amount Q1 . In the adjustment point P2 is the energization time Tq12 and the injection amount Q2 . In the adjustment point P3 the energization time is Tq13 + Tq21, and the injection amount is Q3. In the adjustment point P4 the energization time is Tq14 + Tq22, and the injection amount is Q4.

The fuel injections at the fitting points P2 and P3 the adjustment points P1 until P4 are adjusted by the one-stage excitation and the two-stage excitation, and the types of excitation are different from each other. That is, “Tq12 = Tq13 + Tq21” and “Q2 = Q3”. In short, the fuel injection at the matching point P2 and fuel injection at the match point P3 are carried out with the same target injection quantity.

With the fuel injections at the adaptation points P1 until P4 it is conceivable that the actual injection quantity at the adaptation points P1 until P4 due to an individual difference of the fuel injector 11th and aging deviates. Specifically, it is like in 10 shown, it is conceivable that the actual injection quantity depends on the injection quantity on the basic characteristic curve with the adaptation points P1 until P4 deviates. In this case occur at the adjustment points P1 until P4 Injection quantity deviations ΔQ1, ΔQ2, ΔQ3 and ΔQ4 in each case. In the present embodiment, the adjustment amount of the injection characteristic data is determined based on the injection amount deviations ΔQ1 to ΔQ4 at the respective adjustment points P1 until P4 calculated. The injection characteristic data can be for the fuel injector 11th can be customized for each cylinder.

When in 10 results in a deviation so that the actual injection amount deviates too much from the injection amount on the basic characteristic curve, the adjustment amount (adjustment time) for shortening the excitation time Tq can be calculated as the adjustment amount of the injection characteristic data. If the actual injection amount deviates too little from the injection amount on the basic map, the adjustment amount (adjustment time) for extending the excitation time Tq can be calculated as the adjustment amount of the injection characteristic data. These adjustment amounts can be calculated as values corresponding to the size of the deviation in the injection amount.

11th Fig. 13 is an explanatory time chart showing the fuel injection for the characteristic adjustment at each adjustment point P1 until P4 shows. In 11th shows (a) the fuel injection at the match point P1 , (b) the fuel injection at the match point P2 , (c) the fuel injection at the match point P3 and (d) fuel injection at the match point P4 . 11th Figure 10 shows the transition of the excitation pulse, the transition of the needle lift, and the transition of the injection rate for each of these fuel injections. A time integral value of the injection amount corresponds to the fuel injection amount, and in the injection quantity is shown hatched at each adaptation point.

At the time of fuel injection at the matching point P1 the fuel injection takes place by the one-stage excitation with the excitation time "Tq11". This fuel injection is a very small quantity injection, in which the needle stroke does not reach the lower stroke limit Lmin and the injection quantity does not Q1 amounts to.

At the time of injection at the matching point P2 the injection takes place through the one-step excitation with the excitation time "Tq12". This fuel injection is fuel injection in which the needle lift comes near the lift upper limit Lmax, and the injection amount is Q2. the Fuel injection at the matching point P2 is carried out in such a way that the needle stroke falls within the range from the lower stroke limit Lmin to the upper stroke limit Lmax.

At the time of fuel injection at the matching point P3 the fuel injection takes place by the two-stage excitation with the excitation time "Tq13, Tq21". In this fuel injection, the injection amount becomes the injection amount Q3 that of that of the fuel injection at the matching point P2 corresponds to, and at the end of the first-stage excitation and at the beginning and at the end of the second-stage excitation, the stroke of the needle is kept within the range from the stroke lower limit Lmin to the stroke upper limit Lmax.

At the time of fuel injection at the matching point P4 the fuel injection takes place by the two-stage excitation with the excitation time "Tq14, Tq22". In this fuel injection, the injection amount becomes the injection amount Q4 set that is greater than that of the fuel injection at the matching point P2 and P3 , and at the end of the first-stage excitation and at the beginning and end of the second-stage excitation, the needle stroke is kept within the range from the stroke lower limit Lmin to the stroke upper limit Lmax.

If two-stage excitation is performed, it is conceivable that there may be a delay in the response of the nozzle needle 32 occurs when the movement of the nozzle needle 32 changes from lowering to raising due to the stop of the first stage excitation, and a delay in the response of the nozzle needle 32 occurs when the movement of the nozzle needle 32 changes from lowering to raising due to the start of the second stage excitation. 12th Fig. 13 is a time chart showing the transition of the lift amount of the nozzle needle 32 shows, and a response delay time Td1 occurs when the excitation is stopped and a response delay time Td2 occurs when the excitation is restarted.

In this case, assuming that the interval time TINT in the two-stage excitation is set shorter than the excitation time Td1 when the first-stage excitation is stopped, there is a concern that the adjustment of the response delay will be insufficient. In addition, there is a concern that the adjustment of the response delay will be insufficient if it is assumed that the excitation time Tq2 of the second-stage excitation is shorter than the response delay time Td2 when the excitation is restarted. Therefore, when the injection characteristic data are adjusted, the interval time TINT in the two-stage excitation is set longer than the response delay time Td1 when the first-stage excitation is stopped. Further, in the two-stage excitation, the second-stage excitation time Tq2 is set longer than the response delay time Td2 when the excitation is restarted. These response delay times Td1 and Td2 can be predetermined as conforming values.

13th Fig. 13 is a flowchart showing a procedure of the characteristic adjusting flow for adjusting the injection characteristic data, and this process is repeated by the microcomputer 21 the ECU 20th executed in a predetermined cycle.

In 13th will be in step S31 determines whether there is a fuel injection at the match point P1 should be done or not in step S41 it is determined whether there is fuel injection at the match point P2 should be done or not in step S51 it is determined whether there is fuel injection at the match point P3 should be done or not, and in step S61 it is determined whether there is fuel injection at the match point P4 should be carried out or not. Then, based on the determination results in each of these steps, the fuel injection at each adjustment point P1 until P4 carried out in a suitable manner.

The ECU 20th each fuel injection to adapt the characteristic curve adaptation (fuel injection at each adaptation point P1 until P4 ) in each of the following cases. When a map adjustment command is input from an external device in a vehicle factory or workshop, fuel injection for adjusting the injection characteristics is performed based on the map adjustment command. In the case of a configuration in which the result of the injection characteristic adjustment is stored in a backup RAM of the ECU 20th is stored, for example when the battery is replaced, the fuel injection for adapting the injection characteristic curve can be carried out based on the characteristic curve adaptation command. When the vehicle is coast running, the fuel injection is carried out in order to adapt the injection characteristics. In particular, the fuel injection is carried out for adaptation when the vehicle is running and a clutch of a power transmission system is disengaged with the accelerator device switched off in order to carry out an idling operation, that is to say under the condition that the combustion of fuel in the engine 10 does not affect the operation of the vehicle. In this case, the fuel injection may be performed at one adjustment point or at a plurality of adjustment points during idling. Furthermore, the fuel injection can be carried out at each of the adjustment points P1 until P4 every time the vehicle is driven.

When the fuel injection is at the matching point P1 will be performed in step S32 the energization time Tq11 and the injection amount Q1 than the injection conditions at the match point P1 is set, and the fuel injection is performed under these conditions.

After that, in step S33 the actual injection amount obtained when the fuel injection is at the matching point P1 is carried out. The actual injection amount can be based on, for example, the pressure change in that of the fuel injection device caused by the fuel injection 11th supplied fuel can be estimated. In particular, the ECU calculates 20th that by the fuel injection of the fuel injector 11th generated fuel pressure change amount from the with the aid of the pressure sensor 16 detected fuel pressure and estimates the actual injection amount based on the fuel pressure change amount. In addition, the amount of change in speed (for example, the amount of change in current speed for each predetermined crank angle) caused by the combustion of the fuel injector 11th injected fuel can be calculated, and the actual injection amount can be estimated based on the amount of change in rotational speed.

After that, in step S34 at the adjustment point P1 the adjustment amount of the injection characteristic based on the difference between the injection amount Q1 , which is the target injection amount, and the actual injection amount given in step S33 was obtained, calculated. At this time, for example, in a case where the injection amount is related to the energization time at the matching point P1 is too big as in 10 shown, the amount of adjustment to shorten the excitation time is calculated.

In a case where the fuel injection is at the matching point P2 will be performed in step S42 the energization time Tq12 and the injection amount Q2 than the injection conditions at the match point P2 is set, and the fuel injection is performed under these conditions. After that, in step S43 the actual injection amount obtained when the fuel injection is at the matching point P2 is carried out.

After that, in step S44 at the adjustment point P2 the adjustment amount of the injection characteristic based on the difference between the injection amount Q2 , which is the target injection amount, and the actual injection amount given in step S43 was obtained, calculated. At this time, for example, in a case where the injection amount is related to the energization time at the matching point P2 is too small as in 10 shown, the amount of adjustment to lengthen the excitation time is calculated.

In a case where the fuel injection is at the matching point P3 will be performed in step S52 the energization time Tq13, Tq21 and the injection amount Q3 than the injection conditions at the match point P3 is set, and the fuel injection is performed under these conditions. After that, in step S53 the actual injection amount obtained when the fuel injection is at the matching point P3 is carried out.

After that, in step S54 at the adjustment point P3 the adjustment amount of the injection characteristic based on the difference between the injection amount Q3 , which is the target injection amount, and the actual injection amount given in step S53 was obtained, calculated. At this time, for example, in a case where the injection amount is related to the energization time at the matching point P3 is too big as in 10 shown, the amount of adjustment to shorten the excitation time is calculated.

In a case where the fuel injection is at the matching point P4 will be performed in step S62 the energization time Tq14, Tq22 and the injection amount Q4 than the injection conditions at the match point P4 is set, and the fuel injection is performed under these conditions. After that, in step S63 the actual injection amount obtained when the fuel injection is at the matching point P4 is carried out.

After that, in step S64 at the adjustment point P4 the adjustment amount of the injection characteristic based on the difference between the injection amount Q4 , which is the target injection amount, and the actual injection amount given in step S63 was obtained, calculated. At this time, for example, in a case where the injection amount is related to the energization time at the matching point P4 is too big as in 10 shown, the amount of adjustment to shorten the excitation time is calculated.

In step S65 it is determined whether all adjustment quantities are at the adjustment points P1 until P4 are present or not. Will in step S65 If a positive determination is made, the procedure continues with the following step S66 away. If in step S65 a negative determination is made, the procedure is temporarily terminated.

In step S66 the injection characteristic data using the for each of the Adjustment points P1 until P4 calculated injection quantity adjusted. In particular, in the case where the adjustment time is the adjustment amount at each adjustment point P1 until P4 has been calculated, the adjustment times at the adjustment points P1 and P2 linearly interpolated. The interpolation data is stored as an adjustment amount of the one-step excitation. Furthermore, the adjustment times at the adjustment points P3 and P4 linearly interpolated, and the interpolated data is stored as an adjustment amount of the two-stage excitation. At this point it will be at the adjustment points P2 and P3 at which the target injection quantities have the same injection quantities Q2 and Q3 the adjustment amount is calculated to represent the same point.

The adaptation of the injection characteristic data can be carried out not only for the injection by the one-stage excitation and the injection by the two-stage excitation, but also for the injection by the three-stage excitation. In this case, the adjustment points at which the target injection amount is the same are set as adjustment points for the fuel injection with the two-stage excitation and the fuel injection with the three-stage excitation. Furthermore, the injection characteristic curve data can be adapted in such a way that the actual injection quantities at each of these adaptation points coincide with one another.

For each fuel injection with a different number of excitation stages (for example, fuel injection with one-stage excitation and two-stage excitation), three or more adjustment points can be set in each case. Furthermore, the adjustment injection amount for adjusting the injection amount can be calculated as the adjustment amount of the injection characteristic curve data.

In a case where the adjustment amount of the injection characteristic data is calculated, the energization time Tq is adjusted by using the adjustment amount. In particular, in step S23 of the above-described fuel injection control process in FIG 7th the excitation time Tq is set in each stage by the adjustment amount of the stage. In step S12 from 7th For example, the excitation time Tr can be calculated by the adjustment amount in the one-stage excitation. In the process of adapting the injection characteristic data, the response delay of the nozzle needle 32 corrected. Therefore, the correction of the response delay in step S24 be omitted.

According to this embodiment described in detail above, the following effects are obtained.

When the fuel injector 11th performs the injection of fuel, the number of excitations at an injection opportunity is determined. In addition, an energization time Tq in each stage and an interval time TINT in an injection period when the energization is performed are set so that the fuel injection is performed at the maximum injection rate in the intermediate stroke state. At the same time, the excitation is performed in each stage based on the excitation time Tq in each stage and the interval time TINT. In this case, the amount of lift of the nozzle needle is repeatedly increased and decreased by the multiple-divided excitations in one injection. In this way the nozzle needle 32 can be maintained in a desired intermediate lift state without affecting the intermediate lift range Rf of the fuel injector 11th is enlarged. Further, during the energization in each stage, the injection can be continuously performed at the maximum injection rate, the injection amount can be linearized, and the fuel injection can be performed with high accuracy.

Further, in a case where the fuel injection is performed by the multi-stage excitation on an injection occasion, it is desirable that the linearity of the injection amount with respect to the excitation time Tq is maintained regardless of the number of the excitation stages. In this regard, when at least the one-stage excitation and the two-stage excitation are performed in one injection occasion, the adjustment amount of the characteristic adjustment data is calculated based on the actual injection amount of each excitation. Then, when the adjustment amount of the injection characteristic data is calculated, the energization time Tq is adjusted by using the adjustment amount. In this way, even if the number of energization stages is changed at one injection occasion, fuel injection can be properly performed every injection occasion. As a result, the control of the fuel injection can be optimally implemented.

When the injection characteristics of the one-stage excitation and the two-stage excitation are adjusted, the actual injection amount is obtained when the fuel injection is at the adjustment points P2 and P3 is carried out with the same target injection quantity. In addition, the adjustment points are based on the actual injection quantities P2 and P3 the adjustment amount of the one-stage excitation and the adjustment amount of the two-stage excitation are calculated. In this way, even in a case where the number of one-stage excitations is changed between the first and second stages, the same and excellent linear characteristics are maintained in both stages.

For each fuel injection with a different number of excitation stages (fuel injection with one-stage excitation and fuel injection with two-stage excitation), several adaptation points are established for each injection. In addition, the adjustment amount of the injection characteristic data is calculated based on the deviation of the injection amount at each of the adjustment points. In this case, the injection characteristic data can be appropriately matched to the fuel injections with the different number of energization stages by linear interpolation or the like.

When the injection characteristic data are adjusted, the interval time TINT in the two-stage excitation is set to be longer than the response delay time when the first-stage excitation is stopped. In addition, the second stage excitation time Tq2 is set to be longer than the response delay time when the excitation is restarted, and the second stage excitation is performed. In this way, the injection characteristic data can be appropriately adjusted while taking into account that the response delay of the nozzle needle 32 occurs when first stage excitation is stopped and when second stage excitation is started.

In the case of the fuel injector 11th the valve opening speed of the nozzle needle changes 32 with the beginning of the excitation according to the respective fuel pressure. In this case, by setting the energization time Tq in each stage based on the fuel pressure, the nozzle needle can be adjusted 32 can be maintained in a desired intermediate stroke state during the energization period in each stage while the valve opening speed of the nozzle needle 32 is taken into account.

When the multi-stage excitation is performed on an injection occasion, the fuel pressure is reduced by the fuel injection between the first-stage excitation and the second-stage excitation. In this case, the energization time Tq in each stage is set so that the fuel pressure (pressure of the injected fuel of the fuel injector 11th ) at the second stage excitation is lower than the fuel pressure at the previous stage excitation. In this way, the accuracy of the fuel injection control in multi-stage energization can be further improved.

In the case of the fuel injector 11th the valve closing speed of the nozzle needle changes 32 with the stop of the excitation according to the respective fuel pressure. In this case, by setting the interval time TINT in each stage based on the fuel pressure, the nozzle needle can 32 are maintained in a desired intermediate stroke state during the energization period in each stage, while the valve closing speed of the nozzle needle 32 is taken into account.

During actual operation of the fuel injector 11th the response delay occurs in the nozzle needle 32 on when the nozzle needle 32 at the beginning of the excitement changes in the second or the following stages from lowering to raising. As a result, there is a concern that the linearity of the response of the injection amount with respect to the energization time Tq may be deteriorated. In this connection, the correction value C is set corresponding to the response delay in lifting the needle occurring at the start of the excitation in the second or subsequent stages. In addition, at least one of the excitation time Tq and / or the interval time TINT is corrected in the second or subsequent stages by using the correction value C. Therefore, the linearity of the response of the injection amount with respect to the energization time Tq can be maintained and the controllability can be improved.

In the case of the fuel injector 11th the degree of the response delay (response delay time) of the nozzle needle changes each time 32 at the start of the excitation in the second or subsequent stages according to the fuel pressure. In this case, by setting the correction value C based on the fuel pressure, the linearity of the response of the injection amount with respect to the energization time Tq can be ensured regardless of the fuel pressure.

The control circuit 22nd is configured so that the high voltage and the low voltage are applied in the energization in each stage. In this way it is possible to reduce the response delay of the nozzle needle 32 to suppress when the nozzle needle 32 at the beginning of the excitement changes in the second or the following stages from lowering to raising. Therefore, it is possible to realize a configuration capable of improving the linearity of the response of the injection amount with respect to the energization time.

(Other embodiments)

• -In der obigen Ausführungsform werden sowohl die Erregungszeit Tq als auch die Intervallzeit TINT in jeder Stufe basierend auf dem Kraftstoffdruck variabel eingestellt. Jedoch kann nur die Erregungszeit Tq basierend auf dem Kraftstoffdruck variabel eingestellt werden. Das heißt, in der Kraftstoffeinspritzvorrichtung 11 strömt der Hochdruck-Kraftstoff in der Drucksteuerkammer 37 in die Niedrigdruck-Kammer 64 aus, wenn das Ventil durch die Erregung geöffnet wird. Daher hängt die Geschwindigkeit der Abnahme des Kraftstoffdrucks in der Drucksteuerkammer 37 von der Druckdifferenz zwischen der Hochdruckseite und der Niederdruckseite ab, und die Abhängigkeit des Kraftstoffdrucks von der Hubbewegung der Düsennadel 32 wird groß. Im Gegensatz dazu ist der Kraftstoffdruck weniger abhängig von der Hubbewegung der Düsennadel 32, wenn die Erregung gestoppt wird. Allerdings kann nur die Erregungszeit Tq basierend auf dem Kraftstoffdruck variabel eingestellt werden.
• -In der vorstehend konfigurierten Ausführungsform zur Durchführung der Mehrstufen-Erregung bei einer Einspritzgelegenheit wird der Erregungsimpuls, der korrespondierend zu der erforderlichen Einspritzmenge QR ist, in mehrere Impulse aufgeteilt. Es ist zu beachten, dass diese Konfiguration modifiziert werden kann. Der Erregungsimpuls selbst kann als ein Impuls belassen werden, ohne in mehrere Impulse aufgeteilt zu werden, und eine Erregungsunterbrechungsperiode, die mit der Intervallzeit TINT korrespondiert, kann in dem einen Impuls vorgesehen werden.
• -Bei der obigen Ausführungsform werden beim Anpassen der Einspritzkennlinien zwischen der Einstufen-Erregung und der Zweistufen-Erregung die Ziel-Einspritzmengen Q2 und Q3 an den Anpassungspunkten P2 und P3 auf die gleiche Menge (Q2 = Q3) eingestellt. Es ist zu beachten, dass diese Konfiguration geändert werden kann. Beispielsweise können die Ziel-Einspritzmengen Q2 und Q3 an den Anpassungspunkten P2 und P3 auf „Q2 > Q3“ eingestellt werden. Das heißt, der Anpassungspunkt für die Einstufen-Erregung enthält einen Anpassungspunkt, der eine größere Einspritzmenge aufweist als der Anpassungspunkt für die Zweistufen-Erregung. In diesem Fall können der Bereich, in dem die Anpassung an den Anpassungspunkten P1 und P2 bei der Einstufen-Erregung erfolgt, und der Bereich, in dem die Anpassung an den Anpassungspunkten P3 und P4 bei der Zweistufen-Erregung erfolgt, miteinander überlappt werden. Auf diese Weise können die Einspritzkennlinien besser angepasst werden. Es besteht auch die Möglichkeit, die Ziel-Einspritzmengen Q2 und Q3 an den Anpassungspunkten P2 und P3 auf „Q2 < Q3“ einzustellen.
• -Bezüglich der Anpassung der Einspritzkennliniendaten sind in der vorstehend konfigurierten Konfiguration zwei Anpassungspunkte P1 und P2 bei der Einstufen-Erregung und zwei Anpassungspunkte P3 und P4 bei der Zweistufen-Erregung eingestellt. Diese Konfiguration kann jedoch dahingehend geändert werden, dass die Einspritzkennliniendaten nur an den Anpassungspunkten P2 und P3 mit der gleichen Ziel-Einspritzmenge unter den Anpassungspunkten P1 bis P4 angepasst werden.

The above embodiments can be modified as described below:

• In the above embodiment, both the energization time Tq and the interval time TINT are variably set in each stage based on the fuel pressure. However, only the Excitation time Tq can be variably set based on the fuel pressure. That is, in the fuel injection device 11th the high pressure fuel flows in the pressure control chamber 37 into the low pressure chamber 64 off when the valve is opened by the excitation. Therefore, the rate of decrease in fuel pressure in the pressure control chamber depends 37 on the pressure difference between the high pressure side and the low pressure side, and the dependence of the fuel pressure on the stroke movement of the nozzle needle 32 becomes big. In contrast, the fuel pressure is less dependent on the stroke movement of the nozzle needle 32 when the excitation is stopped. However, only the energization time Tq can be variably set based on the fuel pressure.
• In the embodiment configured above for performing the multi-stage excitation in the event of an injection opportunity, the excitation pulse corresponding to the required injection quantity QR is divided into a plurality of pulses. It should be noted that this configuration can be modified. The excitation pulse itself can be left as one pulse without being divided into a plurality of pulses, and an excitation interruption period corresponding to the interval time TINT can be provided in the one pulse.
• In the above embodiment, when the injection characteristics are adjusted between the one-stage excitation and the two-stage excitation, the target injection amounts become Q2 and Q3 at the adjustment points P2 and P3 to the same amount ( Q2 = Q3) is set. It should be noted that this configuration can be changed. For example, the target injection quantities Q2 and Q3 at the adjustment points P2 and P3 can be set to “Q2> Q3”. That is, the adjustment point for the one-stage excitation includes a adjustment point that has a larger injection amount than the adjustment point for the two-stage excitation. In this case, the area in which the adjustment can be made at the adjustment points P1 and P2 takes place at the one-step excitation, and the area in which the adjustment at the adjustment points P3 and P4 when two-stage excitation occurs, are overlapped with each other. In this way, the injection characteristics can be better adapted. There is also the option of setting the target injection quantities Q2 and Q3 at the adjustment points P2 and P3 to be set to "Q2 <Q3".
• - With regard to the adaptation of the injection characteristic data, there are two adaptation points in the configuration configured above P1 and P2 at the one-step excitation and two adjustment points P3 and P4 set for two-stage excitation. However, this configuration can be changed in such a way that the injection characteristic data only at the fitting points P2 and P3 with the same target injection quantity among the adjustment points P1 until P4 be adjusted.

The control circuit and method described in the present disclosure can be implemented by a specialized computer configured with a memory and a processor programmed to perform one or more particular functions embodied in computer programs of the memory. Alternatively, the controller and method described in the present disclosure can be implemented by a specialized computer configured as a processor with one or more specialized hardware logic circuits. Alternatively, the controller and method described in the present disclosure may be implemented by one or more special purpose computers configured as a combination of a processor and memory programmed to perform one or more functions, and a processor configured with one or more hardware logic circuits. The computer programs can be stored as instructions to be executed by a computer in a physical, non-transferable, computer-readable medium.

It should be noted that while the processes of the embodiments of the present disclosure have been described herein as a particular sequence of steps, other alternative embodiments including various other sequences of these steps and / or additional steps not disclosed herein are within the steps of FIG present disclosure should be.

While the present disclosure has been written with reference to preferred embodiments, it should be understood that the disclosure is not limited to the preferred embodiments and constructions. The present disclosure is intended to cover various modifications and equivalent arrangements. Furthermore, while the various combinations and configurations are indicated as preferred, other combinations and configurations, including more, less, or only a single element, also fall within the scope of the present disclosure as defined by the accompanying claims.

Claims (10)

A fuel injection control device (20) for a fuel injection system, the fuel injection system including a fuel injection device (11) which a drive unit (60) configured to be driven when energized and a valve body (32) configured to open an injection hole (33) in response to driving of the drive unit, the fuel injector configured to change an injection amount in accordance with an energization time of the drive unit, and set an intermediate lift state in which an injection amount of the valve body is a predetermined intermediate lift amount to generate a maximum injection rate, wherein the fuel injection control device is configured to determine the energization time corresponding to the injection amount by using injection characteristic data showing a relationship between the energization time and the injection amount, and to excite the drive unit according to the excitation time, wherein the fuel injection control device comprises: a timing unit configured to determine a number of excitations of the drive unit at an injection occasion, set an excitation time (Tq) at each stage, and set an interval time (TINT) between excitations in order to fuel injection at the maximum injection rate in the intermediate stroke state in perform an injection period in which excitation is performed; an excitation control unit configured to perform excitation on the drive unit based on the excitation time in each stage and the interval time set by the time setting unit; an injection amount acquisition unit configured to acquire an actual injection amount that is an actual value of an injection amount at each excitation when at least one stage excitation in which one stage excitation is performed and two-stage excitation at an injection opportunity -Excitation, in which excitations are carried out in two stages, is carried out; and a characteristic adjustment unit configured to calculate an adjustment amount of the injection characteristic data based on the actual injection amount in each energization obtained by the injection amount acquisition unit, wherein the time adjustment unit is configured to adjust the energization time by using the adjustment amount calculated by the characteristic adjustment unit. The fuel injection control device according to Claim 1 , wherein the injection amount acquisition unit is configured to perform the one-stage excitation and the two-stage excitation at an adjustment point (P2, P3) at which the injection amount is an equal target injection amount and acquire the actual injection amount at each adjustment point, and the characteristic adjustment unit is configured to calculate the adjustment amount of the one-stage excitation and the adjustment amount of the two-stage excitation based on the actual injection amount at the adjustment point where the target injection amount is the same. The fuel injection control device according to Claim 1 or 2 , further comprising: an adjustment point setting unit configured to set, in the injection map data, a plurality of first adjustment points (P1, P2) in a range in which the one-stage excitation can be performed, and a plurality of second adjustment points (P3, P4) is set in a range in which the two-stage excitation can be performed, the injection amount acquisition unit is configured to perform the one-stage excitation at each of the plurality of first adjustment points, the two-stage excitation at each of the Performs a plurality of second adjustment points and obtains the actual injection amount at each of the adjustment points, and the map adjustment unit is configured to adjust the adjustment amount at each energization based on the actual injection amount at each of the plurality of first adjustment points and the plurality of second adjustment points calculated. The fuel injection control apparatus according to any one of Claims 1 until 3 wherein the injection amount acquisition unit is configured to perform the two-stage excitation such that an interval time between a first-stage excitation and a second-stage excitation in the two-stage excitation is longer than an excitation time when the valve body closes due to an excitation stop goes down, and such that an energizing time in the second stage is longer than an energizing time when the valve body goes up due to a restart of the energization. The fuel injection control apparatus according to any one of Claims 1 until 4th , wherein the time setting unit is configured to set the energization time in each stage based on a pressure of the Adjust fuel injector supplied fuel. The fuel injection control device according to Claim 5 wherein the timing setting unit is configured to set the energization time in each stage, taking into account that the pressure of the fuel supplied to the fuel injector in the energization in a later stage is lower than the pressure in the first-stage energization. Fuel injection control device according to any one of Claims 1 until 6th wherein the timing adjustment unit is configured to adjust the interval time based on the pressure of the fuel supplied to the fuel injector. The fuel injection control apparatus according to any one of Claims 1 until 7th , further comprising: a correction unit configured to set, when multi-stage excitation is performed at an injection occasion, a correction value corresponding to a response delay in lifting of the valve body that occurs when the excitation is started in the second or second subsequent stage occurs, and corrects the excitation time in the second or subsequent stage and / or the interval time based on the correction value. Fuel injection control device according to Claim 8 wherein the correction unit is configured to adjust the correction value based on the pressure of the fuel supplied to the fuel injector. Fuel injection control device according to one of the Claims 1 until 9 , further comprising: a drive circuit (22) configured to apply a high voltage at the beginning of the excitation and to apply a low voltage after the application of the high voltage in response to an excitation command to the fuel injector, wherein the drive circuit is configured to apply the Apply the high voltage and the low voltage during excitation in each stage.

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