DE102013105124B4 - Method for determining characteristics of a fuel injection valve - Google Patents

Abstract

A method of determining characteristics of a fuel injection valve (20), the characteristics representing a relationship between an injection amount (Q) of fuel to be injected from a fuel injection valve (20) and a driving time (Tq) of the fuel injection valve (20), the method comprising the following steps:
a reference rate setting step for setting a reference injection rate configuration (Ram) of a reference injector at reference points with injection quantities that differ from one another, the reference injection rate configuration (Ram) representing a change in an injection rate of the reference injector;
a fitting point selection step for selecting a predetermined number of fitting points from the reference points;
a first injection rate determination step for determining an injection rate configuration (Ra) of the fuel injection valve (20) corresponding to the predetermined adjustment points determined in the adjustment point selection step;
an injection rate deviation calculation step for calculating an injection rate deviation (ΔRa) at the adjustment points, which corresponds to a deviation between the reference injection rate design (Ram) and the injection rate design (Ra) determined in the first injection rate determination step;
an interpolation point selection step for selecting an interpolation point from the predetermined number of adjustment points;
an injection rate deviation interpolation step for interpolating the injection rate deviation (ΔRa) at the interpolation point selected by the interpolation point selection step based on the injection rate deviation (ΔRa) calculated by the injection rate deviation calculation step;
a second injection rate determination step for determining the injection rate design (Ra) at the interpolation points based on the reference injection rate design (Ram) at the interpolation point and the injection rate deviation (ΔRa) interpolated by the injection rate deviation interpolation step; and
a drive time calculation step for calculating the drive time (Tq) at the interpolation point based on the injection rate configuration (Ra) determined in the second injection rate determination step.

Description

background

(Technical field)

The present disclosure relates to a method for determining injection characteristics of a fuel injection valve.

(Description of the Related Art)

According to a fuel injection equipment mounted on a conventional internal combustion engine, the fuel injection equipment controls the drive time Tq of the fuel injection valve to the injection quantity Q to control. The relationship between the drive time Tq and the injection quantity Q however, varies with individual fuel injectors made in the factory, even though they are of the same type of fuel injectors. For this reason, before the factory shipment of the fuel injection valves, information regarding the individual fuel injection valves, that is, the drive time, is obtained Tq , determined at an adaptation point, which is determined by a predetermined injection quantity Q and a predetermined supply pressure is defined. Then the determined or detected kenlinie, that is, the Tq -Q characteristic stored in a QR code (registered trademark) as information of the individual fuel injection valve. The engine ECU (electronic control unit) controls the drive time Tq using the information of the single fuel injection valve stored in the QR code, whereby the injection quantity Q the respective fuel injection valves is controlled.

According to a patent document, for example JP 2009-74 536 A , an injection characteristic of the fuel injection valve is determined during the operation of the engine, whereby an injection state of the fuel injection valve is precisely controlled. In particular, a pressure fluctuation pattern at the injection hole is detected when the fuel is injected, so that a model representing a variation in the injection rate associated with the pressure fluctuation at the injection hole is detected. Therefore, the particular model is used as an injection characteristic in the fuel injection equipment.

According to the conventional fuel injection equipment described above, the drive time becomes Tq at an interpolation point, which is defined by the injection amount and the supply pressure, calculated by a linear interpolation, which at the adjustment point on the drive time Tq is applied. The Tq-Q Characteristic, however, has at least one nonlinearity section. Therefore, it is necessary to set a plurality of adjustment points to reduce the accuracy of the accuracy Tq-Q Characteristic curve.

In the DE 103 31 241 A1 The following is disclosed: In a method for fuel quantity comparison in pilot injections of a plurality of injectors for a fuel metering system of an internal combustion engine, wherein values of the drive duration of a single injector are adjusted in a plateau region of the injected fuel quantity by means of a measured injected fuel quantity, it is proposed that in said plateau region of a single injector, a quantity level is selected, in which a measurable change in quantity occurs with changed actuation duration, that a lower limit of the actuation duration and an upper limit of the actuation duration are defined in this quantity level, that in the case of an injector in which a clearly too low injection quantity is measured , the activation duration is set equal to the said upper limit, that in an injector, in which a much too high injection quantity is measured, the activation duration is set equal to said lower limit, and in the case of an injector in which only a slightly too low or slightly too high injection quantity is measured, a suitable actuation period is set within the stated quantity level.

short version

In view of the above-described problems, the present disclosure is intended to provide a method of accurately determining the injection characteristic of the fuel injection valve.

To solve the problems described above, as a first aspect of the present disclosure, there is provided a method for determining the characteristic of a fuel injector, the characteristic being a relationship between an injection amount of fuel to be injected from a fuel injector and represent a drive time of the fuel injector. The method includes the following steps: a reference rate setting step for setting a reference injection rate configuration of a reference injector at reference points with different injection quantities, the reference injection rate configuration representing a change in an injection rate of the reference injector; a fitting point selection step for selecting a predetermined number of fitting points from the reference points; a first injection rate determination step for determining the injection rate configuration of the fuel injection valve according to the predetermined one Fitting points determined in the fitting point selection step; an injection rate deviation calculation step for calculating an injection rate deviation at the adjustment points, which corresponds to a deviation between the reference injection rate design and the injection rate design determined in the first injection rate determination step; an interpolation point selection step for selecting an interpolation point from the predetermined number of adjustment points; an injection rate deviation interpolation step for interpolating the injection rate deviation at the interpolation point selected by the interpolation point selection step based on the injection rate deviation calculated by the injection rate deviation calculation step; a second injection rate determination step for determining the injection rate design at the interpolation points based on the reference injection rate design at the interpolation point and the injection rate deviation interpolated by the injection rate deviation interpolation step; and a drive time calculation step for calculating the drive time at the interpolation point based on the injection rate configuration determined by the second injection rate determination step.

According to the first aspect of the present disclosure, the first injection rate determining step determines the injection rate design at the adjustment points selected from the reference points having mutually different injection quantities. The injection rate design includes injection state fluctuation data due to an individual difference of the injectors. In other words, instead of simply using the drive time, in the first injection rate determining step, the fluctuation data of the injection state may be determined based on the individual difference at the adjustment point. Further, in the injection rate deviation calculating step, the injection rate deviation corresponding to a deviation between the injection rate design and the reference injection rate design determined at the adjustment points is calculated.

Subsequently, in the injection rate deviation interpolation, the injection rate deviation at the interpolation points selected from the predetermined number of adjustment points is interpolated using the injection rate deviation calculated at the adjustment point. Using the injection rate deviation with the mutually different injection quantities, in particular the injection rate deviation is interpolated at the mutually different injection quantities. In the second injection rate determining step, the injection rate design at the interpolation point is determined using the reference injection rate design at the interpolation point and the interpolated injection rate deviation. Moreover, the drive time at the interpolation point is calculated based on the injection rate design determined at the second injection rate determination step.

The specific injection rate design at the interpolation point includes the fluctuation data of the injection state due to the individual difference of the fuel injection valve except for the drive time. Thereby, the drive time, which is calculated from the injection rate design determined at the interpolation points, includes fluctuation data of the injection state due to an individual difference other than the drive time. Thereby, the drive time calculated at the interpolation point according to the first aspect of the present disclosure is able to more accurately represent injection state fluctuation data due to an individual difference compared to the drive time calculated by linear interpolation of the drive time deviation calculated at the adjustment point , Therefore, the injection characteristic at the interpolation points according to the first aspect of the present disclosure can be accurately detected even with fewer adjustment points.

As a fourth aspect of the present disclosure, there is provided a method of determining the characteristic of a fuel injection valve, wherein the characteristic represents a relationship between a supply pressure of a fuel to be supplied to a fuel injection valve and a drive time of the fuel injection valve. The method includes the steps of: a reference rate setting step of setting a reference injection rate design of a reference injector at reference points having mutually different supply pressures for mutually different injection quantities of the fuel to be injected from the fuel injection valve, wherein the reference injection rate design is a change in a reference injector Injection rate of the reference injector represents; a fitting point selecting step of selecting a predetermined number of fitting points from the reference points; a first injection rate determining step for determining the injection rate design of the fuel injection valve according to the predetermined adjustment points determined at the adjustment point selecting step; an injection rate deviation calculating step for Calculating an injection rate deviation at the adjustment points corresponding to a deviation between the reference injection rate design and the injection rate design determined at the first injection rate determination step; an interpolation point selecting step of selecting an interpolation point from the predetermined matching points; an injection rate deviation interpolation step of interpolating the injection rate deviation at the interpolation point selected by the interpolation point selection step based on the injection rate deviation calculated by the injection rate deviation calculating step; a second injection rate determining step of determining the injection rate design at the interpolation points based on the reference injection rate design at the interpolation point and the injection rate deviation interpolated by the injection rate deviation interpolation step; and a drive time calculating step of calculating the drive time at the interpolation point based on the injection rate design determined at the second injection rate determining step.

According to the fourth aspect of the present disclosure, at the adjustment points selected from the reference points having mutually different supply pressures, fluctuation data of the injection state of the fuel injection valve is detected due to an individual difference in the adjustment points. In the injection rate deviation calculating step, the injection rate deviation is calculated. The injection rate deviation is defined as a deviation between the calculated injection rate design and the known reference injection rate design at the adjustment point.

Subsequently, in the injection rate deviation interpolation step, the injection rate deviation at the interpolation point selected from the predetermined number of adjustment points is interpolated using the injection rate deviation calculated at the adjustment points. In particular, the injection rate deviation is interpolated using the injection rate deviation with the mutually different supply pressures between the different supply pressures. Then, in the second injection rate determining step, the injection rate design at the interpolation points is determined based on the reference injection rate design at the interpolation point and the interpolated injection rate deviation. Further, in the drive time calculation step, the drive time is calculated based on the injection rate design determined at the second injection rate determination step.

Thus, the driving time to be calculated at the interpolation point according to the fourth aspect of the present disclosure, as in the first aspect of the present disclosure, includes injection state fluctuation data due to an individual difference other than the driving time. Thereby, according to the fourth aspect of the present disclosure, as in the first aspect of the present disclosure, the injection characteristic at the interpolation point can be accurately detected even with fewer adjustment points.

list of figures

• 1 eine Abbildung, welche eine Gesamtkonfiguration des Kraftstoff-Einspritzsystems zeigt;
• 2 eine Abbildung, welche eine Querschnittsansicht des Kraftstoff-Einspritzventils zeigt, wobei die innere Struktur des Kraftstoff-Einspritzventils dargestellt ist;
• 3 ein Diagramm, welches eine Beziehung zwischen der Einspritzmenge und der Antriebszeit gemäß der ersten Ausführungsform zeigt;
• 4 ein Diagramm, welches eine Einspritzratengestaltung zeigt;
• 5 eine Abbildung, welche eine Abweichung der Einspritzratengestaltung zeigt;
• 6 eine beispielhafte Abbildung, welche ein Verfahren zum Interpolieren einer Abweichung der Einspritzratengestaltung zeigt;
• 7 eine Abbildung, welche eine bei einem Interpolationspunkt bestimmte Einspritzratengestaltung zeigt;
• 8 ein Flussdiagramm, welches einen Vorgang zum Berechnen der Abweichung der Antriebszeit bei einem Anpassungspunkt und einem Interpolationspunkt zeigt;
• 9 ein Diagramm, welches eine Beziehung zwischen der Einspritzmenge und einem Zuführdruck gemäß der zweiten Ausführungsform zeigt;
• 10 ein Diagramm, welches eine Beziehung zwischen der Einspritzmenge und der Antriebszeit gemäß der dritten Ausführungsform zeigt
• 11 eine Abbildung, welche die durch ein Fünfeck genäherte Einspritzratengestaltung zeigt; und
• 12 eine Abbildung, welche die durch ein Sechseck genäherte Einspritzratengestaltung zeigt.

In the attached figures show:

• 1 an illustration showing an overall configuration of the fuel injection system;
• 2 an illustration showing a cross-sectional view of the fuel injection valve, wherein the internal structure of the fuel injection valve is shown;
• 3 a diagram showing a relationship between the injection amount and the drive time according to the first embodiment;
• 4 a diagram showing an injection rate design;
• 5 an illustration showing a deviation of injection rate design;
• 6 an exemplary map showing a method for interpolating a deviation of the injection rate design;
• 7 an illustration showing an injection rate design determined at an interpolation point;
• 8th a flowchart showing a process for calculating the deviation of the drive time at a fitting point and an interpolation point;
• 9 a diagram showing a relationship between the injection amount and a supply pressure according to the second embodiment;
• 10 a diagram showing a relationship between the injection amount and the drive time according to the third embodiment
• 11 an illustration showing the pentagon-shaped injection rate design; and
• 12 an illustration showing the hexagon-shaped injection rate design.

Detailed Description of the Preferred Embodiments

A method for determining the characteristic of the fuel injection valve will be described below based on various embodiments of the present disclosure with reference to the drawings as follows. It should be noted that, in the embodiments, substantially the same configurations are denoted by the same reference numerals, and a repetitive explanation thereof will be omitted.

First Embodiment

The fuel injection valve according to the present disclosure is mounted on a common rail fuel injection system that is adapted to a four-stroke piston diesel engine. The fuel injection valve according to the present disclosure is used when high-pressure fuel (for example, diesel fuel having an injection pressure higher than 1000 atmospheric pressure) is directly injected into the combustion chamber of the engine cylinder. In this type of engine, a combustion cycle is executed at 720 ° CA (crank angle) every four cylinders # 1 to # 4.

First, an overall configuration of the fuel injection system according to the first embodiment will be described with reference to FIG 1 described. The fuel injection system according to the fuel injection system includes a fuel tank 10 , a fuel pump 11 , a common rail 12 , an injector 20 (Fuel injection valve), which is arranged at the respective cylinders # 1 to # 4, and an ECU 50 ,

The fuel tank 10 is used to store fuel (diesel fuel) for the machine. A line 10a is arranged such that this the fuel tank 10 and the fuel pump 11 combines.

The fuel pump 11 contains a high pressure pump 11a and a low pressure pump 11b , The low pressure pump 11b delivers the fuel from the fuel tank 10 , The high pressure pump 11a puts that through the low pressure pump 11b delivered fuel under pressure and transmits the pressurized fuel to the common rail at a predetermined time 12 , An amount of fuel transfer to the high pressure pump 11a is transmitted, that is, an amount of fuel delivery from the fuel pump 11 , is controlled by a suction control valve (SCV) 11c adjusted, which is at an inlet side of the fuel pump 11 is arranged.

The low pressure pump 11b is configured, for example, as a trochoid feed pump. The high pressure pump 11a is configured, for example, as a piston pump. Both the low pressure pump 11b as well as the high pressure pump 11a are driven by a drive shaft 11d driven. The drive shaft 11d rotates together with a crankshaft 41 which represents an output shaft of the machine. In other words, the high pressure pump 11a and the low pressure pump 11b are driven by the output power of the machine.

The common rail 12 saves the fuel pump 11 transferred fuel such that it is in a high pressure state. The pressure within the common rail 12 becomes a supply pressure Pc of the fuel which is supplied to the injector 20 should be performed. In addition, the common rail distributes 12 the stored high-pressure fuel and leads it through a high-pressure line 14 which are used with the respective injectors 20 is arranged to respective fuel inlets 22 , A restrictor 12a is between the common rail 12 and the high pressure line 14 arranged. The restrictor 12a is used to detect a pressure pulsation of the fuel coming from the common rail 12 to the high pressure line 14 flows to suppress.

The injector 20 contains a fuel inlet 22 , which is used to make it over the high pressure line 14 to allow added fuel into the injector 20 to stream. The injector 20 also includes a fuel outlet 21 , which is used to release excess fuel from it. The fuel outlet 21 is over the line 18 with the fuel tank 10 connected. In other words, any excess fuel reaches the fuel tank 10 back. In addition, the injector contains 20 an attached plate or a sign 28 (Storage device) with a attached QR code (registered trademark). In the QR code is information regarding the individual difference of the injector 20 saved. It should be noted that the detailed structure of the injector 20 described later.

The ECU 50 is used as an engine control device for the vehicle on which the injector is mounted 20 is arranged. The ECU 50 detects in particular detection values by various sensors, such as a crank angle sensor 42 , an accelerator pedal sensor 44 , are detected and determines an operating state of the machine and a request from the driver. Then the ECU operates 50 the suction control valve in response to the operating state of the machine or the driver's request 11c or different Actuators, such as the injector 20 which controls the machine.

Below is a detailed structure of the injector 20 regarding 2 described. The injector 20 contains a body 23 with a cylindrical body. A nozzle hole 24 which injects high pressure fuel is at the front portion or the tip portion in the axial direction of the body 23 educated. A pressure sensor 40 is at the nozzle hole 24 assembled. The pressure sensor 40 is able to detect the pressure fluctuation pattern of the fuel pressure when the injector 20 works to inject the high pressure fuel. Note that the axial direction is defined as a longitudinal direction of the fuel injection valve.

In the body 23 is a high pressure diffuser 25 trained to the fuel inlet 22 and the nozzle hole 24 connect to. In the body 23 is a needle valve 26 added which is the nozzle hole 24 opens and closes. A surface 26a which at the front portion of the needle valve 26 is designed so that it has a conical surface 23a which is formed in the body, is brought into contact or separated therefrom, whereby the nozzle hole 24 locked or released.

It is also in the body 23 between the inner peripheral surface of the body 23 and the outer peripheral surface of the needle 26 a fuel passage 23e with a circular shape extending in the axial direction, and at a rear (side opposite to the nozzle hole) of the needle valve 26 is a back pressure chamber 23b educated. In the back pressure chamber 23b is a needle spring 31 arranged which the surface 26a towards the conical surface 23a (towards the nozzle hole). The one from the fuel inlet 22 High-pressure fuel entering is through the high-pressure passage 25 to the fuel passage 23e and the back pressure chamber 23b guided.

In the body 23 is also a housing section 23c formed, which a back pressure control valve 32 receives. The housing section 23c is formed such that a low pressure passage 33 , the high pressure passage 25 and the back pressure chamber 23b be connected to each other. When the back pressure control valve 32 through a valve spring 34 is displaced to a low-pressure side valve section 35a to close, the fuel pressure in the back pressure chamber 23b elevated. On the other hand, when the backpressure control valve 32 , which is the valve spring 34 opposite, a high pressure side valve section 35b closes, the fuel pressure in the back pressure chamber 23b lowered. The low pressure passage 33 is with the fuel outlet 21 connected.

In the body 23 is on the back of the housing section 23c a small opening piston 36 added, which is adjacent to the back pressure control valve 32 located. A large opening piston 37 is on the back of the small opening piston 36 over an oil-tight section 23d added. In the oil-tight section 23d is a fluid, for example injection fuel, filled. The displacement of the piston 37 is through that in the oil-tight section 23d filled fluid enlarged and to the small opening piston 36 transfer.

In the body 23 is on the back of the large opening piston 37 also a piezoelectric actuator 30 added. A piezo spring 38 urges the large opening piston 37 towards the piezoelectric actuator 30 , The piezoelectric actuator 30 is built up by a piezo stack, which expands or contracts due to the piezoelectric effect, and serves as an electrical actuator, which the back pressure control valve 32 actuated.

Especially when driving power to the piezoelectric actuator 30 the piezo stack expands. Then the big opening piston overcomes 37 the power of the piezo spring 38 and moves towards the nozzle hole 24 , Then the small opening piston presses 36 the back pressure control valve 32 against the high-pressure side valve section 35b , Consequently, the fuel pressure in the back pressure chamber 23b lowered so that the needle valve 26 the force of the needle spring 31 overcomes and stands out from the conical surface 23a moved away, causing fuel from the nozzle hole 24 is injected. If, however, the drive power is not on the piezoelectric actuator 30 is applied, the piezo stack contracts so that the back pressure control valve 32 the low-pressure side valve section 35a closes, causing the fuel pressure in the back pressure chamber 23b is increased. This brings the needle valve 26 by the force of the needle spring 31 with the conical surface 23a in contact, which stops the fuel injection. As a result, the injection amount Q can be based on a conduction phase (ie, drive time Tq) of the piezoelectric actuator 30 being controlled.

The following is a method for determining the injection characteristic of the injector adapted to the fuel injection system 20 with reference to the 3 to 7 described. In 3 is a relationship between the injection amount Q and the drive time Tq shown. Three curves in 3 put Tq-Q Characteristics with mutually different supply pressures Pc (Pc) 1 , Pc 2 , Pc 3 , as in 3 shown). Concerning the Tq-Q Characteristics at the respective supply pressure Pc provide black, filled circles a reference drive time Tqm the master injector (master injector) at reference points with mutually different injection quantities Q The master injector is defined as a reference injector whose reference injection time is determined in advance. Likewise in relation to the Tq-Q Characteristics at the respective supply pressure Pc white circles set the drive time Tq of the injector 20 in which the drive time Tq is actually measured at fitting points selected from the reference points (predetermined injection amount), and triangles set the driving time Tq which is interpolated at an interpolation point between matching points (selected plurality of injection quantities). The following is a method for interpolating the drive time Tq described.

A drive time deviation is conventional ΔTq and a drive time Tq at interpolation points for the respective supply pressures Pc calculated such that a deviation (drive time deviation ΔTq ) between the reference drive time Tqm and the drive time Tq is linearly interpolated at adjustment points. In the 3 shown Tq-Q However, the linearity does not seem to be observed in a range in which the injection quantity is small. Hence the accuracy of the Tq-Q - Characteristics at the interpolation points in a region where the injection quantity is small deteriorates if the number of adjustment points is not sufficient. According to the first embodiment, the injection rate configuration Ra is determined using fluctuation data of the injection state on the basis of an individual difference in the respective adaptation points. Then the injection rate design Ra interpolated at the interpolation points so that the drive time Tq is calculated with an interpolated injection rate design.

The injection rate design Ra represents a fluctuation pattern of the injection rate, which is caused by switching the injector drive signal ON-OFF. According to the first embodiment, the fuel injection system approaches the injection rate design Ra by a trapezoidal shape which is similar to the fluctuation pattern of the actual injection rate design as in 4 is shown.

• einer Einspritz-Start-Verzögerungszeit Td, welche einer Phase von einem Zeitpunkt, bei dem das Antriebssignals auf EIN geschaltet wird, bis zu einem Zeitpunkt, bei dem damit begonnen wird, den Kraftstoff einzuspritzen, entspricht;
• einer Einspritz-Ende-Verzögerungszeit Tee, welche einer Phase von einem Zeitpunkt, bei dem das Antriebssignals auf AUS geschaltet wird, bis zu einem Zeitpunkt, bei dem der Kraftstoff vollständig eingespritzt ist, entspricht;
• einer maximalen Einspritzrate Qdm;
• einer Einspritz-Erhöhungsrate Q2up, welche einer Erhöhungsrate der Einspritzrate für eine vorbestimmte Phase entspricht, wenn die Einspritzung startet; und
• einer Einspritz-Verringerungsrate Q2dn, welche einer Verringerungsrate der Einspritzrate in einer vorbestimmten Phase entspricht, welche bei dem Ende der Kraftstoffeinspritzung abgeschlossen ist.

The injection rate design approached by the trapezoid Ra is defined using five parameters, including:

• an injection start delay time td which corresponds to a phase from a time when the drive signal is turned ON until a time when it starts to inject the fuel;
• an injection end delay time T e which corresponds to a phase from a time point at which the drive signal is turned OFF to a time point at which the fuel is fully injected;
• a maximum injection rate square decimeter ;
• an injection rate of increase Q2up which corresponds to an increase rate of the injection rate for a predetermined phase when the injection starts; and
• an injection reduction rate Q2dn , which corresponds to a reduction rate of the injection rate in a predetermined phase, which is completed at the end of the fuel injection.

The area within injection rate design Ra , which corresponds to the area or area of the trapezoid, corresponds to the injection quantity Q , The above-described 5 parameters are detected by detecting a pressure fluctuation pattern at the injection hole 24 calculated. In other words, as in the above-described patent document number JP 2009 - 74 536 A is disclosed, the fuel injection system detects the pressure fluctuation at the injection hole 24 , whereby the injection rate design Ra is detected, which is related to this pressure fluctuation.

5 Fig. 10 is a diagram showing a deviation of injection rate design. In 5 are the injection rate design Ra (solid line) of the injector 20 and a reference injection rate design Ram (broken line) of the master injector. The reference injection rate design Ram is an injection rate design which is pre-set along with the reference drive time Tqm is determined at the reference point. The reference injection rate design Ram and the reference drive time Tqm are determined in advance with a test performed for the master injector. Regarding the reference drive time Tqm and the reference inject rate design Ram of the master injector, the data was determined at sufficient data points (ie, at a sufficiently small interval) for the supply pressure Pc and the injection amount. It should be noted that the injection rate design Ra along with the drive time Tq at the fitting points is determined when the injector 20 is tested in the factory test, or is determined when the injector 20 is driven, while the machine is working. As in 5 is shown, there is a deviation due to the individual difference in the injectors (injection rate deviation ΔRa ) between the reference injection rate design Ram and the injection rate design Ra. Thus, the fuel injection system calculates the injection rate deviation ΔRa at the respective adjustment points. In particular, deviations ΔTd . ΔTee . ΔQdm . ΔQ2up . ΔQ2dn between the respective five parameters of the reference injection rate design Ram and the respective five parameters of injection rate design Ra calculated.

The following is the injection rate deviation ΔRa at the interpolation points using the injection rate design deviation calculated at the adjustment points with the interpolation points ΔRa calculated. In particular, as in 6 is shown using the deviations ΔTd . ΔTee . ΔQdm . ΔQ2up . ΔQ2dn , which are calculated based on the adjustment points with the interpolation points, all deviations ΔTd . ΔTee . ΔQdm . ΔQ2up . ΔQ2dn interpolated at the interpolation points. According to the first embodiment, a linear interpolation is used for the interpolation. However, other interpolations, such as a second interpolation, can be used. Since the deviation for the respective parameters is interpolated at the respective interpolation points, the injection rate configuration deviation can ΔRa can be calculated in a simple manner.

In addition, as in 7 shown is the injection rate design Ra at the interpolation points based on the reference injection rate design Ram at the interpolation points and the interpolated injection rate deviation ΔRa certainly. More specifically, the sum of the reference injection rate design Ram at the interpolation points, that is, tdm . teem . Qdmm . Q2mm and Q2dnm and the interpolated deviations ΔTd . ΔTee . ΔQdm . ΔQ2up . ΔQ2dn is calculated to the five parameters td . tea . square decimeter . Q2up and Q2dn to calculate. Then, the upper base and the lower base of the trapezoid are calculated such that the height of the trapezoid corresponds to Qdm, inclinations of the legs Q2up and Q2dn correspond and the area of the trapezium of the injection quantity Q equivalent. Consequently, the injection rate design Ra be determined at the interpolation points. Therefore, the injection rate design Ra be determined at the interpolation points.

The following is the drive time Tq at the interpolation points based on injection rate design Ra calculated at the interpolation points. In particular, the length of the lower edge of the calculated injection rate design becomes Ra as an injection phase tqr Are defined. Then the drive time Tq calculated such that the injection start delay time td to the injection phase tqr is added, and that the injection end delay time Tee is subtracted therefrom ( 4 ). Accordingly, the drive time calculated at the interpolation points contains Tq compared to the drive time calculated using conventional interpolation methods Tq more fluctuation data of the injection state of the injector 20 due to the individual difference. Therefore, the Tq-Q Characteristics are accurately detected at the interpolation points, even if compared to the conventional method less adjustment points are used.

According to the first embodiment, the drive time deviation becomes ΔTq which indicates a deviation between the reference drive time Tqm and the drive time Tq corresponds calculated at the interpolation points. The ECU 50 stores the relationship between the injection quantity Q and the reference drive time Tqm at the reference points in advance. In addition, the drive time deviation is ΔTq at the fitting point and the interpolation point in the on the plate 28 contained QR code stored before the injector 20 shipped from the factory. The drive time deviation ΔTq at the fitting points and the interpolation points stored in the QR code are read out by a reading equipment and in the ECU 50 stored (first storage step, second storage step and third storage step). Therefore, the ECU controls 50 the drive time Tq using the injection characteristic of the injector 20 at the respective adjustment points and the interpolation points, whereby the injection quantity Q is controlled. The storage unit, which is the drive time deviation ΔTq is stored at the adjustment point and the interpolation point is not limited to the QR code, for the storage unit, however, other storage units, such as an IC memory, can be used.

Below is with reference to 8th processing for calculating the drive time deviation ΔTq described at the adjustment points and the interpolation points. This processing is carried out by measuring equipment with a microcomputer and other units before the injector 20 is delivered from the factory. It should be noted that the reference drive time Tqm and the reference injection rate configuration Ram of the master injector, which have different injection quantities at the reference points Q , contained in the different feed pressures pc be determined in advance in the measuring equipment described above be saved (i.e., reference rate setting step, second reference rate setting step).

At the steps S1 to S5 the process measures injection characteristics of the injector 20 at the fitting points. At step S1 a fitting point is selected from the reference points. More specifically, the process selects from the feed pressures pc with the reference points a feed pressure pc (Adjustment Feed Pressure) at which the drive time Tq and injection rate design Ra of the injector 20 to be measured (adjustment feed pressure selecting step). Subsequently, the process selects with respect to the selected feed pressure pc a reference point from the reference points at the selected feed pressure pc and determines the injection quantity Q corresponding to the selected reference point (ie, selected injection amount) to be used for the fitting point (fitting point selecting step).

Subsequently, the process determines at step S2 the drive time Tq (certain drive time Tq ) at a time when the injection quantity Q that of the injector 20 injected fuel to the selected injection quantity Q becomes. Then the drive signal is controlled in such a way that this is for a phase corresponding to the determined drive time Tq ON is to the injector 20 drive. Below is at step S3 the drive time deviation ΔTq which is a deviation between the reference drive time Tqm and the determined drive time Tq at the adjustment point is calculated (first drive time deviation calculation step).

In addition, at step S4 determines the injection rate designation Ra at the adjustment point (first injection rate detection step). That is, the process determines five parameters of the injection rate design. At step S5 becomes the injection rate deviation ΔRa between the injection rate design determined at the adjustment point Ra and the reference injection rate design Ram is calculated (injection rate deviation calculation step). In other words, deviations from the respective five parameters are calculated.

It then determines if the next fitting point should be processed. In other words, the process determines whether all the necessary adjustment points for determining the injection characteristics of the injector 20 were selected. If the process determines that not all necessary adjustment points have been selected, the process determines that the next adjustment point is selected ( S6 : YES) and returns S1 back. Then the steps S1 to S5 Repeatedly executed. If, on the other hand, it is determined that all necessary adjustment points have been selected, the process determines that no next adjustment point is selected ( S6 : NO) and proceeds to the next step.

At the steps S7 to S13 become the injection characteristics of the injector 20 determined at the interpolation points. At step S7 the interpolation point is selected. In particular, the process selects the interpolation point (ie, injection quantity Q at the interpolation point) from the adjustment points (ie, injection quantity Q at the adjustment point), which at step S1 were selected (interpolation point selection step).

The process then interpolates at step S8 the injection rate deviation ΔRa at the selected interpolation point using the injection rate deviation ΔRa , which was calculated at the adjustment points with the interpolation point in between (injection rate deviation interpolation step). In other words, the respective deviations of the five parameters at the interpolation point are interpolated using the deviation of the five parameters calculated at the adjustment points with the interpolation point in between.

The process reads at step below S9 the reference injection rate design Ram at the interpolation point. At step S10 is the injection rate design Ra based on that at step S9 Read-out reference injection rate design Ram and that at step S8 interpolated injection rate deviation ΔRa determined (second injection rate determination step). In particular, the respective five parameters at the interpolation point are calculated based on the respective five parameters of the reference injection rate design and the respective deviations of the interpolated five parameters. Then the injection rate design Ra at the interpolation point based on the five parameters at the interpolation point and the injection amount Q determined at the interpolation point.

Below is at step S11 the drive time Tq at the interpolation point based on the at step S10 certain injection rate design Ra calculated (drive time calculation step). Then the process reads at step S12 the reference drive time Tqm at the interpolation point off. At step S13 becomes the drive time deviation ΔTq which is a deviation between the at step S12 read reference drive time Tqm and the at step S11 calculated drive time Tq corresponds, calculated (second drive time deviation calculating step).

Subsequently, at step 14 determines if the next interpolation point is selected. In this step, the process determines whether all necessary interpolation points for determining the injection characteristics of the injector 20 were selected. If not all necessary interpolation points have been selected, the process determines that the next interpolation point is selected ( S14 : YES) and returns to step S7 back to the steps S7 to S13 to execute repeatedly. If, on the other hand, it is determined that all necessary interpolation points have been selected, the process determines that the next interpolation point is not selected ( S14 : NO) and ends the process.

The first embodiment described above has the following advantages.

At step S4 becomes the injection rate design Ra at the from the reference points with mutually different injection quantities Q determined adjustment points. The injection rate design Ra contains injection status fluctuation data due to the individual difference of the injector 20 , That is, at step S4 are fluctuation data of the injection state due to the individual difference of the injector 20 certainly. At step S5 becomes the injection rate deviation ΔRa which indicates a deviation between the reference injection rate design Ram at the adjustment point and the particular injection rate design Ra corresponds, calculated.

Then step S8 the injection rate deviation ΔRa at an interpolation point selected from predetermined adjustment points using the injection rate deviation calculated at the adjustment points ΔRa interpolated. In particular, using the injection rate deviation ΔRa with different injection quantities Q the injection rate deviation ΔRa in the injection quantities Q interpolated. At step S10 is the injection rate design Ra at the interpolation points based on the reference injection rate design Ram at the interpolation point and the interpolated injection rate deviation ΔRa certainly. In addition, at step S11 the drive time Tq at the interpolation point based on that at step S10 certain injection rate design Ra calculated.

The injection rate design to be determined at the interpolation point Ra contains fluctuation data of the injection state due to the individual difference with the exception of the drive time Tq , Therefore contains the drive time Tq , which is based on the injection rate design determined at the interpolation point Ra is calculated, not just the drive time Tq , but also the fluctuation data of the injection state of the injector 20 so that at step S13 calculated drive time deviation .DELTA.Ta is able to measure the fluctuation of the injection state due to the individual difference compared to the drive time deviation caused by the application of a linear interpolation to the drive time deviation calculated at the adjustment point .DELTA.Ta is calculated to represent exactly. As a result, injection characteristics at the interpolation points can be determined more accurately even if fewer adjustment points are used.

The injection rate Ra becomes at each step S1 selected feed pressures at the respective interpolation points. In other words, the injection characteristics can be at the respective interpolation points at each of the steps S1 selected feed pressures pc can be determined with high accuracy.

Second Embodiment

In the second embodiment, the process selects from the feed pressures pc with the reference points an adaptation feed pressure with which the drive time Tq and injection rate design Ra of the injector 20 be measured. Further, the process selects an interpolation feed pressure between the adjustment feed pressures (interpolation feed pressure selection step).

Subsequently, the process selects an injection quantity Q as a second interpolation point with the interpolation feed pressure (second interpolation selection step), and with the adjustment feed pressure, the process selects an injection amount Q , which is equal to the injection quantity Q is, as the second interpolation point. Then the drive time Tq is calculated at the interpolation point in a similar manner as in the first embodiment (second drive time calculation step), and the process interpolates the drive time Tq at the second interpolation point using the drive time calculated at the interpolation point (drive time interpolation point).

The relationship between the interpolation supply pressure pc2 , the adjustment feed press Pc1 and Pc3 and the injection quantity Q is this as in 9 shown. The rectangle corresponds to the second interpolation point at the interpolation supply pressure pc2 , The circles correspond to the adjustment points at the adjustment feed pressure Pc1 and Pc3 , The triangles correspond to the interpolation points at the adjustment feed pressures Pc1 and Pc3 with the same injection quantity Q like the second interpolation points. First The process interpolates the injection rate design in a manner similar to that in the first embodiment Ra at the interpolation point using injection rate design Ra which at the adjustment point for the respective adjustment supply pressures Pc1 and Pc3 between which there is the adjustment feed pressure pc2 is determined. The process calculates the drive time Tq at the interpolation point based on the interpolated injection rate design Ra , In addition, the process runs using the drive time Tq , which at the respective interpolation points of the adjustment supply pressures Pc1 and Pc3 a linear interpolation for the drive time is calculated Tq at the second interpolation point.

According to the second embodiment, the drive time Tq with the same injection quantity at the interpolation points described above Q how to calculate the second interpolation points for a predetermined number of adjustment feed pressures including the interpolation feed pressure. Then the drive time Tq at the second interpolation point using the calculated drive time Tq interpolated. Accordingly, the drive time Tq the supply pressure pc , which differs from that of the above-described adjustment points, can be detected in a simple manner.

Third Embodiment

In the third embodiment, the process sets the reference points with different supply pressures Pc for the different injection quantities. In 10 is the relationship between the drive time Tq and the injection quantity Q shown. As in 10 is shown, the two straight lines (horizontal broken line) represent different injection quantities from one another Q represents. The three curves represent three Tq-Q -Characteristic curves, which each represent the characteristic curve based on different feed pressures pc demonstrate. Regarding the respective injection quantities Q the circles filled in black represent the reference drive time Tqm at the reference points with different supply pressures pc Regarding the respective injection quantities Q the white or empty circles represent the drive time Tq of the injector 20 represents which is actually measured at the adjustment points selected from the reference points (predetermined feed pressures). The triangle represents the drive time Tq which is interpolated at the interpolation point between the adjustment points (selected plurality of supply pressures). Regarding 8th A processing is described in which the drive time deviation ΔTa with respect to the interpolation point and the adaptation point is calculated. This processing is carried out by measuring equipment with a microcomputer and other units before the injector is shipped from the factory 20 executed. In the second embodiment, the repetitive description of processing identical to that of the first embodiment is omitted.

In the equipment described above, the reference drive time Tqm and the reference injection rate designation Ram become the different injection rates from each other Q at the reference points with different supply pressures pc set in advance to the measuring equipment described above (reference rate setting process). At step S1 the process selects from the injection quantities Q at which the reference points described above are set, the injection quantity Q according to the drive time Tq of the injector 20 and the injection rate design Ta which are actually to be measured. Then the process selects the supply pressure pc for the adjustment point based on the reference points described above for the selected injection quantity Q (Matching point-selection step). Below are the steps S2 to S6 repeated in a manner similar to that of the first embodiment.

Subsequently, the process selects at step S7 the interpolation point (supply pressure pc for the interpolation step) between those in step S1 selected adjustment points (feed pressure pc for the adjustment point) for that at step S1 selected injection quantity Q (Interpolation selection step). Below are the steps S8 to S14 repeated in a manner similar to that of the first embodiment.

According to the third embodiment, the process determines at step S4 at the adaptation points selected from the reference points with different supply pressures, fluctuation data of the injection state due to an individual difference of the injector 20 , Then at step S5 the injection rate deviation ΔRa between the injection rate design determined at the adjustment point Ra and the already known reference injection rate design Ram.

Subsequently, at step S8 the injection rate deviation ΔRa at the interpolation points selected from predetermined adjustment points using the injection rate deviation calculated at the adjustment points ΔRa interpolated. In other words, by using the injection rate deviation ΔRa with a different feed pressure pc becomes the injection rate deviation ΔRa in which different feed pressure pc interpolated. Then the process at step S10 the injection rate design Ra at the interpolation point based on the reference injection rate design Ram at the interpolation point and the interpolated injection rate deviation ΔRa , In addition, at step S11 the drive time Tq at the interpolation point using the at step S10 determined injection rate design Ra calculated.

This contains the drive time calculated at the interpolation points Tq in a manner similar to the first embodiment, more fluctuation data of the injection state of the injector 20 due to an individual difference. So you can Tq-Q -Characteristics at the interpolation points are recorded precisely, even if a smaller number of adjustment points is used.

(Further embodiment)

According to the embodiments described above, the processing in the steps S1 to S14 performed at the factory before shipping the product and the drive time deviations ΔTq at the respective fitting points and the respective interpolation points are in the on the plate 28 stored QR code stored. However, the processing steps S1 to S6 be performed in the factory and the injection rate deviation ΔRa at the respective adjustment points, which at step S5 may be calculated in the ECU 50 get saved.

In this case, the ECU calculates 50 while the machine is working the drive time Tq using the in advance in the ECU 50 stored reference drive time Tqm and the reference injection rate design Ram. The ECU 50 especially the steps S8 to S11 at the interpolation points as a target injection quantity Q responding to a driving condition of the vehicle, thereby increasing the drive time Tq is calculated.

According to the further embodiment, the ECU stores 50 the reference drive times Tqm and the reference injection rate configuration Ram at the respective reference points and the injection rate deviation ΔRa at the respective adjustment point. Then the ECU calculates 50 while the machine is operating in response to a driving state of the vehicle TQ at the interpolation points as a target injection amount Q , The injection quantity can accordingly Q can be precisely controlled in order to react appropriately to the drive state of the vehicle.

In the above-described embodiments, the injection rate configuration is approximated by a trapezoidal shape, but the injection rate design can be approximated by other configurations such as the trapezoidal shape. As in 11 will be explained using an example that the injection rate design Ra is approximated by a pentagon in which the upper base and the lower base are parallel.

• der ersten Einspritz-Start-Verzögerungszeit Td1, welche einer Verzögerungszeitphase von einem Zeitpunkt, bei dem das Antriebssignal auf EIN geschaltet wird, bis zu einem Zeitpunkt, bei dem die Einspritzung tatsächlich beginnt, entspricht;
• der zweiten Einspritz-Start-Verzögerungszeit Td2, welche einer Verzögerungszeitphase von einem Zeitpunkt, bei dem das Antriebssignal auf EIN geschaltet wird, bis zu einem Zeitpunkt eines Wendepunktes, bei dem sich die Einspritz-Erhöhungsrate verändert, entspricht;
• der Einspritz-Ende-Verzögerungszeit Tee, welche einer Phase von einem Zeitpunkt, bei dem das Antriebssignals auf AUS geschaltet wird, bis zu einem Zeitpunkt, bei dem der Kraftstoff vollständig eingespritzt ist, entspricht;
• der maximalen Einspritzrate Qdm;
• der Einspritz-Start-Erhöhungsrate Q2up1, welche einer Erhöhungsrate der Einspritzrate während einer Phase von einem Zeitpunkt, bei dem die Einspritzung beginnt, bis zu einem Zeitpunkt eines Wendepunktes, bei dem sich die Einspritz-Erhöhungsrate verändert, entspricht;
• der Einspritz-Erhöhungsrate Q2up2, welche einer Erhöhungsrate der Einspritzrate während einer Phase von einem Zeitpunkt des Wendepunktes, bei dem sich die Einspritz-Erhöhungsrate verändert, bis zu einem Zeitpunkt, bei dem die Einspritzrate maximal wird, entspricht; und
• der Einspritz-Ende-Verringerungsrate Q2dn, welche einer Verringerungsrate der Einspritzrate während einer vorbestimmten Phase entspricht, bis die Einspritzung abgeschlossen ist,
• und der Einspritzmenge Q, welche einem Bereich innerhalb der Einspritzratengestaltung Ra entspricht.

The injection rate design Ra , which is approximated by a pentagonal shape, is defined by seven parameters, including:

• the first injection start delay time Td1 which corresponds to a delay time phase from a point in time at which the drive signal is switched ON to a point in time at which the injection actually begins;
• the second injection start delay time Td2 which corresponds to a delay time phase from a time at which the drive signal is turned ON to a time of a turning point at which the injection increase rate changes;
• the injection end delay time tea which corresponds to a phase from a time at which the drive signal is switched OFF to a time at which the fuel is fully injected;
• the maximum injection rate square decimeter ;
• the injection start increase rate Q2up1 which corresponds to an increase rate of the injection rate during a phase from a point in time at which the injection starts to a point in time at a turning point at which the injection increase rate changes;
• the injection increase rate Q2up2 which corresponds to an increase rate of the injection rate during a phase from a time of the turning point at which the injection increase rate changes to a time at which the injection rate becomes maximum; and
• the end-of-injection rate of reduction Q2dn which corresponds to a decrease rate of the injection rate during a predetermined phase until the injection is completed,
• and the injection quantity Q , which corresponds to a range within the injection rate design Ra.

In this case, the process determines the seven parameters described above at the respective adjustment points. Then, in a similar manner as in the above-described embodiments, the deviations in the respective parameters are calculated and interpolated, whereby the injection rate deviation ΔRa is calculated. Further, at the respective interpolation points, the respective parameters of the interpolated injection rate deviation become ΔRa and adding the respective parameters of the reference injection rate design Ram at the interpolation points to calculate the seven parameters of the injection rate design Ra at the interpolation points.

Then the size of the turning points (ie, injection rate) is based on Td1 . Td2 and Q2up1 calculated. Then the process calculates lengths (time) of the upper base and the lower base of the pentagon based on the size of the turning points, the height of the pentagon Qdm, slopes of the three edges of the pentagon Q2up1 . Q2up2 and Q2dn and the area or area of the pentagon Q (ie, the amount of injection). Consequently, the injection rate design Ra be determined at the interpolation point. The drive time Tq is calculated such that the injection end delay time Tee is a sum of the actual injection time tqr , which corresponds to the lower edge of the pentagon, and the first injection start delay time Td1 is subtracted to the drive time Tq to calculate.

It should be noted that the parameter is not limited to the parameters described above, but other parameters may be used. For example, instead of Q2up2 a turning point injection rate Qdm2 be used, which corresponds to the injection rate at the inflection point. In addition, different parameters can be used, provided the shape of the pentagon using the parameter and the injection quantity Q can be determined.

In addition, a hexagon-approached injection rate design Ra, whose upper base and lower base are parallel to each other, is exemplified as in FIG 12 is shown.

• der ersten Einspritz-Start-Verzögerungszeit Td1, welche einer Verzögerungszeitphase von einem Zeitpunkt, bei dem das Antriebssignal auf EIN geschaltet wird, bis zu einem Zeitpunkt, bei dem die Einspritzung tatsächlich beginnt, entspricht;
• der zweiten Einspritz-Start-Verzögerungszeit Td2, welche einer Verzögerungszeitphase von einem Zeitpunkt, bei dem das Antriebssignals auf EIN geschaltet wird, bis zu einem Zeitpunkt eines ersten Wendepunktes, bei dem sich die Einspritz-Erhöhungsrate verändert, entspricht;
• der ersten Einspritz-Ende-Verzögerungszeit Tee1, welche einer Phase von einem Zeitpunkt, bei dem das Antriebssignal auf AUS geschaltet wird, bis zu einem Zeitpunkt, bei dem die Einspritzung abgeschlossen ist, entspricht;
• der zweiten Einspritz-Ende-Verzögerungszeit Tee2, welche einer Phase von einem Zeitpunkt, bei dem das Antriebssignal auf AUS geschaltet wird, bis zu einem Zeitpunkt eines zweiten Wendepunktes, bei dem sich die Einspritz-Verringerungsrate verändert, entspricht;
• der maximalen Einspritzrate Qdm;
• der Einspritz-Start-Erhöhungsrate Q2up1, welche einer Erhöhungsrate der Einspritzrate während einer Phase von einem Zeitpunkt, bei dem die Einspritzung beginnt, bis zu einem Zeitpunkt eines ersten Wendepunktes, bei dem sich die Einspritz-Erhöhungsrate verändert, entspricht;
• der Einspritz-Erhöhungsrate Q2up2, welche einer Erhöhungsrate der Einspritzrate während einer Phase von einem Zeitpunkt des ersten Wendepunktes, bei dem sich die Einspritz-Erhöhungsrate verändert, bis zu einem Zeitpunkt, bei dem die Einspritzrate maximal wird, entspricht; und
• der Einspritz-Ende-Verringerungsrate Q2dn1, welche einer Verringerungsrate der Einspritzrate während einer vorbestimmten Phase von einem Zeitpunkt des zweiten Wendepunktes bis zu dem Ende der Einspritzung entspricht; und
• der Einspritz-Verringerungsrate Q2dn2, welche einer Verringerungsrate der Einspritzrate in einer Phase von einem Zeitpunkt, bei dem die Einspritzrate maximal wird, bis zu dem zweiten Wendepunkt entspricht, und der Einspritzmenge Q, welche einem Bereich innerhalb der Einspritzratengestaltung Ra entspricht.

The injection rate design approximated by the hexagon Ra is determined based on nine parameters, including:

• the first injection start delay time Td1 which corresponds to a delay time phase from a point in time at which the drive signal is switched ON to a point in time at which the injection actually begins;
• the second injection start delay time Td2 which corresponds to a delay time phase from a point in time at which the drive signal is switched ON to a point in time of a first turning point at which the injection increase rate changes;
• the first injection end delay time Tee1 which corresponds to a phase from a time at which the drive signal is switched OFF to a time at which the injection is completed;
• the second injection end delay time Tee2 which corresponds to a phase from a point in time at which the drive signal is switched OFF to a point in time at a second turning point at which the injection reduction rate changes;
• the maximum injection rate Qdm;
• the injection start increase rate Q2up1 , which corresponds to an increase rate of the injection rate during a phase from a point in time at which the injection begins to a point in time at a first turning point at which the injection increase rate changes;
• the injection increase rate Q2up2 which corresponds to an increase rate of the injection rate during a phase from a point in time of the first turning point at which the injection increase rate changes to a point in time at which the injection rate becomes maximum; and
• the end-of-injection rate of reduction Q2dn1 which corresponds to a decrease rate of the injection rate during a predetermined phase from a time of the second turning point to the end of the injection; and
• the injection reduction rate Q2dn2 which corresponds to a decrease rate of the injection rate in a phase from a time at which the injection rate becomes maximum to the second turning point and the injection amount Q , which corresponds to a range within the injection rate design Ra.

In this case, the process determines the nine parameters described above at the respective adjustment points. Then, in a manner similar to the above-described embodiments, the process calculates the deviations for each of the parameters and interpolates the deviation, thereby increasing the injection rate deviation ΔRa is calculated. In addition, the process calculates the sum of the respective parameters of the injection rate deviation ΔRa which is interpolated at the interpolation points and the respective parameter of the reference injection rate design Ram at the interpolation point to calculate the nine parameters of the injection rate design at the interpolation points. Subsequently, the size of the first inflection point (injection rate) is based on Td1 . Td2 and Q2upl calculates and the magnitude of the second inflection point (injection rate) is based on Tee1 . Tee2 and Q2dn1 calculated. Then, the process calculates lengths of the upper base and the lower base of the hexagon based on the height of the first inflection point, the height of the second inflection point, the height of the hexagon Qdm, slopes of the four edges of the hexagon Q2up1 . Q2up2 . Q2dn1 and Q2dn2 and the area of the hexagon (injection rate). Consequently, the injection rate design Ra be determined at the interpolation points. The process calculates the drive time Tq such that the first injection end delay time Tee1 from the sum of the first injection start delay time Td1 and the injection phase Tqr is subtracted according to the length of the lower edge of the hexagon.

It should be noted that the parameter is not limited to the parameters described above, but other parameters can be used. For example, instead of Q2dn2m a second inflection point injection rate Qdm3 be used, which corresponds to the injection rate at the second inflection point. Further, various parameters may be used provided that the shape of the hexagon is based on the parameters and the injection quantity Q is determined.

If the injection rate design Ra is approached by a pentagon or a hexagon, compared to the approximation by a trapezoidal shape, it is possible to design the injection rate Ra to be approximated in such a way that it corresponds to the actual injection rate design (pattern). If the injection rate design Ra closer to an injection rate design in order to be closer to the actual injection rate design, more precise injection characteristic curves can be determined. The injection rate design Ra can be approximated by polygons with multiple sides, such as a heptagon, if multiple parameters are used.

Claims (10)

A method of determining characteristics of a fuel injection valve (20), wherein the characteristics include a relationship between an injection amount (Q) of a fuel to be injected from a fuel injection valve (20) and a drive time (Tq) of the fuel injection valve (20), the method comprising the following steps: a reference rate setting step for setting a reference injection rate (Ram) design of a reference injector at reference points having mutually different injection quantities, the reference injection rate design (Ram) representing a variation of an injection rate of the reference injector; a fitting point selecting step of selecting a predetermined number of fitting points from the reference points; a first injection rate determining step of determining an injection rate design (Ra) of the fuel injection valve (20) in accordance with the predetermined adjustment points determined at the adjustment point selecting step; an injection rate deviation calculating step of calculating an injection rate deviation (ΔRa) at the adjustment points corresponding to a deviation between the reference injection rate design (Ram) and the injection rate design (Ra) determined at the first injection rate determining step; an interpolation point selecting step for selecting an interpolation point from the predetermined number of fitting points; an injection rate deviation interpolation step for interpolating the injection rate deviation (ΔRa) at the interpolation point selected by the interpolation point selection step, based on the injection rate deviation (ΔRa) calculated by the injection rate deviation calculating step; a second injection rate determining step of determining the injection rate design (Ra) at the interpolation points based on the reference injection rate design (Ram) at the interpolation point and the injection rate deviation (ΔRa) interpolated by the injection rate deviation interpolation step; and a drive time calculation step for calculating the drive time (Tq) at the interpolation point based on the injection rate design (Ra) determined at the second injection rate determination step. Method according to Claim 1 wherein the reference rate setting step includes a second reference rate setting step that sets the reference injection rate design (Ram) according to mutually different supply pressures (Pc) of the fuel supplied to the fuel injection valve (20), the second reference rate setting step setting an adjustment supply pressure Selecting step which selects a predetermined number of adjustment feed pressures from the mutually different feed pressures (Pc), the first injection rate determining step, the injection rate deviation calculating step, the interpolation point selecting step, the injection rate deviation interpolation step, the second injection rates Determining step and the drive time calculating step for the respective adjustment feed pressures. Procedure according to Claim 2 the method including: an interpolation supply pressure selection step for selecting an adjustment supply pressure from the predetermined number of adjustment supply pressures as the interpolation supply pressure; a second interpolation selection step for selecting the injection quantity (Q) as a second interpolation point; a second drive time calculation step for calculating the drive time (Tq) for the injection amount (Q), which is identical to the injection amount as the second interpolation point, at the predetermined number of adjustment supply pressures with the interpolation supply pressure; and a drive time interpolation step for interpolating the drive time (Tq) at the second interpolation points using the drive time (Tq) calculated in the second drive time calculation step. A method of determining characteristics of a fuel injection valve (20), wherein the characteristics include a relationship between a supply pressure (Pc) of a fuel to be supplied to a fuel injection valve (20) and a drive time (Tq) of the fuel injection valve (FIG. 20), the method comprising the following steps: a reference rate setting step for setting a reference injection rate (RAM) design of a reference injector at reference points having mutually different supply pressures (Pc) for mutually different injection quantities (Q) of the fuel to be injected from the fuel injection valve (20), the reference Injection rate design (Ram) represents a change in an injection rate of the reference injector; a fitting point selecting step of selecting a predetermined number of fitting points from the reference points; a first injection rate determining step of determining an injection rate design (Ra) of the fuel injection valve (20) in accordance with the predetermined adjustment points determined at the adjustment point selecting step; an injection rate deviation calculating step of calculating an injection rate deviation (ΔRa) at the adjustment points corresponding to a deviation between the reference injection rate design (Ram) and the injection rate design (Ra) determined at the first injection rate determining step; an interpolation point selecting step of selecting an interpolation point from the predetermined matching points; an injection rate deviation interpolation step for interpolating the injection rate deviation (ΔRa) at the interpolation point selected by the interpolation point selection step, based on the injection rate deviation (ΔRa) calculated by the injection rate deviation calculating step; a second injection rate determining step of determining the injection rate design (Ra) at the interpolation points based on the reference injection rate design (Ram) at the interpolation point and the injection rate deviation (ΔRa) interpolated by the injection rate deviation interpolation step; and a drive time calculation step for calculating the drive time (Tq) at the interpolation point based on the injection rate design (Ra) determined at the second injection rate determination step. Procedure according to one of the Claims 1 to 4 , wherein the injection rate design is determined by five parameters which include: an injection start delay time (Td) which corresponds to a time phase from a point in time at which a drive signal applied to the fuel injection valve (20) is switched ON, up to corresponds to a point in time at which the fuel is started to be injected; an end-of-injection delay time (Tee) corresponding to a time phase from a time when the drive signal is turned OFF to a time when the fuel is fully injected; a maximum injection rate (Qdm); an injection increase rate (Q2up) corresponding to an increase rate of the injection rate for a predetermined phase when the injection starts; and an injection decrease rate (Q2dn), which corresponds to a decrease rate of the injection rate in a predetermined phase, which is completed at the end of the fuel injection. Procedure according to Claim 5 , wherein in the drive time calculation step the drive time (Tq) is calculated based on an injection phase, which is based on the injection rate design (Ra) determined in the second injection rate determination step, the injection start delay time (Td) and the injection end Delay time (tea) is calculated. Method according to Claim 5 or 6 wherein the injection rate deviation (ΔRa) calculated by the injection rate deviation calculating step is defined as a deviation between respective five parameters of the reference injection rate design (Ram) at the adjustment point and respective five parameters of the injection rate design (Ra) at the adjustment point. Procedure according to Claim 7 , wherein the injection rate deviation (ΔRa) interpolated in the injection rate deviation interpolation step is defined such that respective deviations of the five parameters are interpolated using the five parameters calculated at the adjustment points. Procedure according to one of the Claims 1 to 8th , further comprising the steps: a reference drive time setting step for setting a reference drive time (Tqm) so that it is a drive time of the reference injector set in advance; a first drive time deviation calculation step for calculating a drive time deviation (ΔTq) between the drive time (Tq) detected at the adjustment points and the reference drive time (Tqm); a second drive time deviation calculation step for calculating a drive time deviation (ΔTq) between the drive time (Tq) detected at the interpolation points and the reference drive time (Tqm); a first storing step for storing a relationship between the injection amount (Q) at the reference point and the reference driving time (Tqm) in advance in an engine control unit (50) in which the fuel injection valve (20) is mounted; and a second storage step for storing the drive time deviations (ΔTq) calculated at the adaptation points and the interpolation points in a storage device (28) which is arranged at the fuel injection valve (20). Procedure according to one of the Claims 1 to 8th , further comprising the steps of: a reference drive time setting step for setting a reference drive time (Tqm) so that it is a drive time of the reference injector set in advance; and a third storage step for storing the reference drive time (Tqm), the reference injection rate design (Ram) and the injection rate deviation (ΔRa) calculated at the adjustment points in advance in a machine control unit (50), in which the fuel injection valve (20) is mounted, wherein the engine control unit (50) mounted on a vehicle with an engine interpolates the injection rate deviation (ΔRa) at the interpolation points as a target injection amount in response to a driving state of the vehicle while the machine is working.

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