DE102008042714A1 - Fuel injection condition detecting device for diesel internal combustion engine in e.g. passenger car, has injection amount calculation device calculating fuel injection amount based on calculated results of another two calculation devices - Google Patents

Abstract

The device has an injection amount calculation device calculating a fuel injection amount based on an oscillation wave form that is produced from pressure detected by a fuel pressure sensor (20a) e.g. common rail pressure sensor. Another injection amount calculation device calculates the injection amount based on pressure difference between pressure detected before starting of injection and pressure detected before end of the injection. A third injection amount calculation device calculates the injection amount based on calculated results of the former and the latter calculation devices.

Description

The The present invention relates to a detection device for a fuel injection state that is an injection state detected by fuel injected from an injector.

In the prior art, a known common rail fuel injection system is known in which fuel used in combustion in an internal combustion engine is stored in a common rail (pressure accumulator) in a high pressure state and in which the fuel discharged from the common rail is distributed, is injected from an injector. In general, in this type of conventional system, the pressure of the stored fuel is detected by a fuel pressure sensor (a common rail pressure sensor) attached to the common rail and driving various components constituting a fuel delivery system such as a fuel rail Fuel pump, which supplies the fuel to the common rail, and controls the injector based on the detection result of the sensor (as, for example, in the patent document 1: JP-A-2006-200378 is described).

According to the Knowledge and knowledge of the inventor serves when an injection state the fuel actually injected from the injector (For example, an injection amount, an injection rate and the like) can be detected, the detection value as an important parameter for controlling the fuel injection system with high accuracy. For example, by setting operating command values for the different components (for example the injector) the fuel injection system based on the detection amount calculated or corrected, the components with high accuracy to be controlled.

however has none of the different types of prior art proposed Fuel injection systems means for detecting the injection state of the fuel actually from the injector is injected. Accordingly, there is room for an improvement of the current fuel injection system to achieve a highly accurate control.

It It is an object of the present invention to provide a detection device to provide for the fuel injection state, the one Injection state of the fuel detected, the actual is injected from an injector, whereby the control accuracy a fuel injection system is improved.

• (a) einen Kraftstoffdrucksensor, der in einem Kraftstoffkanal, der sich von dem Druckspeicher zu einem Einspritzloch der Einspritzeinrichtung erstreckt, an einer Position angeordnet ist, die sich näher zu dem Einspritzloch als zum Druckspeicher befindet, um einen Kraftstoffdruck zu erfassen, der mit dem Kraftstoffeinspritzen aus dem Einspritzloch schwankt;
• (b) einen ersten Einspritzmengenabschätzabschnitt zum Schätzen einer Kraftstoffeinspritzmenge auf der Grundlage einer Schwankungswellenform, die in Verbindung mit dem Kraftstoffeinspritzen bewirkt wird, aus dem erfassten Druck, der durch den Kraftstoffdrucksensor erfasst wird;
• (c) einen zweiten Einspritzmengenabschätzabschnitt zum Schätzen der Kraftstoffeinspritzmenge auf der Grundlage einer Druckdifferenz zwischen dem erfassten Druck vor dem Beginn des Einspritzens und dem erfassten Druck nach dem Ende des Einspritzens aus dem erfassten Druck; und
• (d) einen Einspritzmengenberechnungsabschnitt zum Berechnen der Kraftstoffeinspritzmenge auf der Grundlage von beiden Abschätzergebnissen des ersten und des zweiten Einspritzmengenabschätzabschnitts.

According to one aspect of the present invention, a fuel injection state detecting apparatus is applied to a fuel injection system that injects fuel stored in an accumulator from an injector and has the following components (a) to (d):

• (a) a fuel pressure sensor disposed in a fuel passage extending from the accumulator to an injection hole of the injector at a position closer to the injection hole than the accumulator to detect a fuel pressure injected with the fuel from the injection hole fluctuates;
• (b) a first injection amount estimating section for estimating a fuel injection amount based on a fluctuation waveform caused in connection with the fuel injection from the detected pressure detected by the fuel pressure sensor;
• (c) a second injection amount estimating section for estimating the fuel injection amount based on a pressure difference between the detected pressure before the start of the injection and the detected pressure after the end of the injection from the detected pressure; and
• (d) an injection amount calculating section for calculating the fuel injection amount based on both of the estimated results of the first and second injection amount estimating sections.

Of the Pressure of the fuel in the injection hole of the injector varies in connection with the injection of the fuel. however is in the device of the aforementioned patent document 1, the fuel pressure sensor (the common rail pressure sensor) on the Accumulator attached because the fuel pressure sensor detecting the Fuel pressure in the accumulator has as a goal. The pressure fluctuation, which is caused in connection with the injection is in the Pressure accumulator weakened. Therefore it is for one such conventional device difficult, the pressure fluctuation to capture with high accuracy.

In contrast, according to the above-explained aspect of the present invention, the fuel pressure sensor is disposed at a position closer to the injection hole than to the accumulator as in the aforementioned component (a). Therefore, the pressure fluctuation in the injection hole can be detected before the pressure fluctuation in the accumulator is weakened. Accordingly, the change of the actual injection amount as a fluctuation waveform of the detected pressure can be detected accurately. Therefore, the fuel injection amount based on the detected fluctuation waveform (by the first injection amount estimation section: the above-described component (b)) are estimated.

For example, the fuel injection amount is estimated on the basis of the appearance times (occurrence times) of the change points P1, P3 and a pressure maximum reduction amount Pβ (an amount of maximum decrease) as shown in (c) in FIG 5 is shown. The change point P1 is a pressure decrease start point that results in the fluctuation waveform in connection with the start of the injection. The change point P3 is a pressure increase end point resulting in the fluctuation waveform associated with the end of injection. More precisely, a correlation results as in sections (b) and (c) in 5 is shown between the fluctuation waveform of the detected pressure P and the change (the course) of an injection rate R (one injection amount per unit time). Therefore, the change of the injection rate R can be estimated on the basis of the above-described change points P1 and P3, the maximum fall amount Pβ and the like that occur in the fluctuation waveform. A hatched area S shown in section (b) in FIG 5 is shown, the injection quantity Q is equivalent. An example of the estimation by the first injection amount estimating section is estimating the fuel injection amount by calculating the area S.

The Inventors have come to the realization that a detection value of the detected pressure contains a detection variation, and that the detection variation (in particular the variation of the maximum waste amount Pβ) appears more noticeable when the injection quantity increases. Therefore, to have an influence of the detection variation to reduce the estimation result, the inventors Scheme for estimating the injection amount by the second Injection amount estimation section (the above-mentioned Component (c)) in addition to the injection amount estimation method developed by the first injection amount estimation section. That is, a pressure difference between the detected pressure before the start of injection and the detected pressure after End of injection is interrelated with the actual one Injection quantity. Therefore, the fuel injection amount on the Basis of the pressure difference can be estimated.

According to the aforementioned aspect of the present invention becomes the injection amount calculating portion (the above-mentioned component (d)) for calculating the fuel injection amount based on the estimation results of the first and second injection amount estimation sections intended. Therefore, the influence of the estimation variation be reduced compared to the case where the injection quantity on the basis of the estimation result of the first injection amount estimation section is calculated, so that the injection quantity with a high accuracy can be detected.

According to the aforementioned aspect of the present invention the fuel pressure sensor is arranged at a position that closer to the injection hole than to the accumulator located. Accordingly, the change of the injection amount (i.e., the injection state) of the actual injected one Fuel detected as the fluctuation waveform of the detected Pressure, and the injection quantity can with high accuracy be recorded. Thus, an innovative fuel injection state detection device be provided. Therefore, the fuel injection system with high accuracy using the detection result the fuel injection state detecting device controlled become.

According to another aspect of the present invention, the fuel injection condition detecting apparatus further comprises: an injection rate calculating portion for calculating a progression waveform of a fuel injection rate based on the fluctuation waveform of the detected pressure; and an injection rate correcting section for correcting the history waveform such that a fuel injection amount indicative of an integration value of the history waveform (for example, the area of the hatched area S in FIG 5 ), approaches the fuel injection amount calculated by the injection amount calculating section.

Accordingly, can the course waveform of the actual injection rate (Actual injection rate) also as an injection state in addition to the injection quantity (the injection state) of the actually injected one Fuel are detected. In addition, the gradient waveform will the injection rate corrected to the fuel injection amount, the calculated based on the history waveform of the injection rate is to approximate the fuel injection amount passing through the injection amount calculating section is calculated. Therefore, can the injection rate waveform (that is, the injection state) be detected with a high accuracy.

According to another aspect of the present invention, the first and second injection amount estimating sections perform the estimation based on the detected pressure of the fuel pressure sensor, which is detected when a fuel pumping period for fuel pumping Pumping to the pressure accumulator of the fuel is not covered with an injection period for injecting the fuel from the injection hole.

In in the case where the pressure fluctuation associated with the Injection of the fuel is effected with the fuel pressure sensor is detected, the fluctuation waveform of the detected pressure at the time when the fuel pumping period coincides with the Fuel injection period covers, a waveform, which is generated by the fuel pumping amount to the fluctuation waveform at the time when the overlap (overlap) does not occur, is added. In other words, that added Fuel pumping is a disturbance for the detected pressure (the fluctuation waveform), the is used for estimating the fuel injection amount. Therefore, when the fuel injection amount based on the detected Pressure is estimated, such a disturbance can, if the fuel injection amount by the first and the second injection amount estimation section the estimation accuracy will be degraded. Furthermore is in the detection variation that is included in the detection value of the Pressure, the variation of the maximum amount of waste Pβ high, as mentioned above. The added Fuel pumping amount has a great influence on the maximum amount of waste Pβ. Therefore, there is a specific problem with regard to to the aforementioned deterioration of the estimation accuracy.

in the In contrast, according to the above-explained Aspect of the present invention, the estimation on the Based on the detected pressure that is detected when the fuel pumping period does not coincide with the fuel injection period. Therefore, the above-mentioned estimation be executed on the basis of the detected pressure, to which this component (the fault) due to fuel pumping is not is added. Finally, the estimation accuracy be improved.

According to one Another aspect of the present invention is the detection device for the fuel injection state in a fuel injection system a multi-cylinder internal combustion engine, which uses a variety having injectors, and the fuel pressure sensor is provided for each of the plurality of injectors. The fuel injection condition detecting device Further, a pump fluctuation waveform acquiring section for Obtaining a fluctuation waveform that covered in the Pressure of the fuel pressure sensor results, according to a Non-injection cylinder among the many cylinders, being in each from them one injection and one non-injection consecutive is executed, and in connection with the fuel pump a fuel pump is effected to the pressure accumulator. The non-injection cylinder is a cylinder where fuel injection is currently in progress not executed. The first and second injection amount estimation sections estimate the fuel injection amount in an injection cylinder when the fuel pump period coincides with the fuel injection period, based on the fluctuation waveform that is obtained is determined by placing a component of the fluctuation waveform through the pump fluctuation waveform obtaining section is obtained, is subtracted from the fluctuation waveform of the fuel pressure sensor, which corresponds to the injection cylinder. The injection cylinder is a cylinder in which fuel injection is present is performed.

According to this Construction becomes the fluctuation waveform (the fuel pump component as the disturbance variable), which in conjunction with the fuel pumping is effected on the basis of the detected Pressure of the fuel pressure sensor detected, the non-injection cylinder equivalent. The estimate explained above is performed on the basis of the fluctuation waveform, which is obtained by the fuel pumping component of the fluctuation waveform is subtracted from the fuel pressure sensor, the injection cylinder equivalent. Therefore, the first and second injection amount estimation sections also estimate the fuel injection amount when the fuel pumping period overlaps with the fuel injection period.

According to another aspect of the present invention, the second injection amount estimating section uses the detected pressure of the fuel pressure sensor detected when a start of injection is commanded by an injection command signal (for example, at a time t1 in the section (a) of FIG 5 ) commanding the injection of the fuel as the detected pressure before the start of injection.

According to another aspect of the present invention, the second injection amount estimating section uses the detected pressure of the fuel pressure sensor detected when starting the injection (for example, at a time t3 in the section (a) in FIG 5 ) is commanded by an injection command signal of the next injection, as the detected pressure after the end of the injection.

The pulsation of the detected pressure is low at the times t1 and t3. Therefore, the values of the detected pressure before the start of the On injection and the detected pressure after the end of the injection used for the estimation by the second injection amount estimation section can be obtained with high accuracy. Therefore, the pressure difference used for the estimation by the second injection amount estimating section can be obtained with high accuracy, and the estimation by the second injection amount estimating section can be performed with high accuracy.

According to one Another aspect of the present invention is the detection device for the fuel injection state in a fuel injection system applied, which is capable of a multi-stage injection for injecting fuel in multiple ways from the same Implement injector per combustion cycle. Of the first injection amount estimating section estimates a Fuel injection amount of each injection stage of the multi-stage injection based on a pressure fluctuation waveform associated with each Injection varies. The second injection amount estimation section estimates a fuel injection amount per combustion cycle based on a pressure difference between the detected pressure before the start of injection of the first injection stage in the Multi-stage injection and the detected pressure after the end of the Injecting the last injection stage in the multi-stage injection.

The fuel injection state detecting device further includes a main injection amount estimating section for estimating an injection amount (for example, Q3 in FIG 7 ) of a main injection, the injection quantity of which is the largest of the injection amounts in the multi-stage injection estimated by the first injection amount estimation section, by calculating a total amount (Q1 + Q2 + Q4 in FIG 7 ) of the injection amount or injection quantities of the injector or injectors other than the main injection is subtracted from the fuel injection amount per combustion cycle estimated by the second injection amount estimating section.

Of the Injection amount calculating section calculates the main injection quantity the main injection based on the injection amount of the main injection among the injection quantities estimated by the first injection amount estimation section and the injection amount estimated by the main injection amount estimation section becomes.

In the case of calculating the injection amount of each injection stage when the multi-stage injection is when both estimates by the first and second injection amount estimating sections for each of the many injection stages are and the fuel injection amount based on both Estimate results is the estimation process complicated and required by both estimates Process effort is high. More precisely, the pressure difference, those for the estimation by the second injection amount estimation section used for each of the many injection stages and the process of the injection amount calculation section on the basis of both estimation results is for each of the many injection stages required.

in the In contrast, the above-described aspect of the present invention seeks Invention a simplification of the estimation process and a reduction of the process effort by the injection quantity is calculated in a simple way when the multi-stage injection is performed.

The is called, according to the aspect described above According to the present invention, the fuel injection amount for each injection stage is estimated by the first injection amount estimation section. Since one injection amount of another injection except a main injection is low, is an error due to the Estimation error of the other injection except the main injection in relation to the total injection quantity low. Therefore, for the other injection except the Main injection, the estimation result by the first injection amount estimation section considered as a true value, without the estimation by execute the second injection amount estimation section. As for the main injection, the main injection quantity becomes based on the estimation result by the main injection amount estimation section, the estimation result of the second injection quantity estimating section and the estimation result by the first injection amount estimation section used, calculated. That is, the main injection amount estimating section estimates the injection quantity of the main injection by the total amount of injection (or injection) of the others Injection (or other injections) except the main injection, calculated by the first injection amount estimation section is subtracted from the fuel injection amount per combustion cycle which is determined by the second injection amount estimation section is estimated.

Thus, according to the above-described aspect of the present invention, it is only required to measure the differential pressure (pressure difference) between the detected pressure before the start of injection of the first injection stage and the first injection stage detected pressure after the end of the injection of the last injection stage as the pressure difference used for the estimation by the second injection amount estimation section. Accordingly, the obtaining process can be simplified and the processing cost can be reduced. It is only necessary to perform the process by the injection amount calculating section that calculates the fuel injection amount based on both of the estimation results of the first and second injection amount estimation sections for only the main injection. Accordingly, the process by the injection amount calculating section can be simplified, and the processing cost can be reduced. Moreover, the injection amount of the main injection is calculated on the basis of both estimation results as in the first aspect of the present invention. Therefore, the injection amount (the injection state) can be detected with high accuracy.

According to another aspect of the present invention, the injection rate calculating section calculates a routing waveform of a main injection rate of the main injection based on a pressure fluctuation waveform that fluctuates in association with the main injection. The injection rate correcting section corrects the main injection rate progression waveform to an approximation of a main injection amount calculated as an integration value of the main injection rate gradient waveform (for example, an area having a hatched area S3 in FIG 7 ), to the main injection amount calculated by the injection amount calculating section.

According to According to this structure, the fuel injection state detecting device, which the function for calculating the course waveform of the main injection rate in addition to the function for calculating the main injection amount has to be redefined. In addition, the gradient waveform will the main injection rate is corrected so that the main injection quantity, based on the waveform of the main injection rate is calculated, is approximated to the main injection quantity, calculated by the injection amount calculating section. Therefore, a highly accurate history waveform can be obtained.

According to another aspect of the present invention, the second injection amount estimating section uses the detected pressure of the fuel pressure sensor detected when the start of injection of the first injection stage (for example, at time t11 in the section (a) of FIG 7 ) is commanded by an injection command signal commanding the multi-stage injection of the fuel as the detected pressure before the start of injection.

According to another aspect of the present invention, the second injection amount estimating section uses the detected pressure of the fuel pressure sensor detected when the start of injection of the first injection stage (for example, at a time t51 in the section (a) of FIG 7 ) is commanded by an injection command signal of a next multi-stage injection, as the detected pressure after the end of the injection.

The Pulsation of the detected pressure is at times t11 and t51 low. Therefore, the values of the detected pressure may occur the beginning of the injection and the detected pressure after the end of the Injection, for estimating by the second Injected amount estimation section can be used with be achieved with high accuracy. Therefore, the pressure difference, for estimating by the second injection amount estimating section used to be obtained with high accuracy, and the estimation by the second injection amount estimating section may be executed with a high accuracy.

According to In another aspect of the present invention, the detection device for the fuel injection state, a fuel pressure sensor, a time estimating section for the injection start and the injection end, an injection amount estimating section and an injection rate calculating section.

Of the Fuel pressure sensor is in a fuel channel extending from the pressure accumulator to an injection hole of the injector extends, arranged at a position that is closer to the injection hole as to the accumulator to the fuel pressure fluctuation to detect the fuel injection from the injection hole.

Of the Timing section for the injection start and the injection end estimates an injection start time and a Injection end time based on a fluctuation waveform, which is caused in connection with the fuel injection, off the detected pressure detected by the fuel pressure sensor becomes.

Of the Injection amount estimating section estimates a Fuel injection amount based on the pressure difference between the detected pressure before a start of the injection and the detected Pressure after the end of injection from the detected pressure.

Of the Injection rate calculation section calculates a gradient waveform the fuel injection rate based on the injection start time and the injection end time determined by the time estimating section estimated for the injection start and the end of injection and the fuel injection amount estimated by the injection amount estimation section becomes.

According to this structure, the fuel pressure sensor is disposed at a position closer to the injection hole than to the accumulator located. Therefore, the pressure fluctuation in the injection hole can be detected before the pressure fluctuation in the pressure accumulator is weakened. Accordingly, the change of the actual injection amount is accurately detected as a fluctuation waveform of the detected pressure become. Therefore, the injection start timing and the injection end timing based on the detected fluctuation waveform (by the Timing section for the injection start and the end of injection) are estimated.

The Gradient waveform of the fuel injection rate can be based on the maximum amount of waste Pβ in addition to the the estimation result described above (that is, the injection start timing and the injection end time). However, because the detection variation of the maximum waste amount Pβ is high, as above is mentioned, the injection rate waveform can not exactly calculated by the method described above. Therefore, the inventors have a scheme for estimating the Fuel injection amount based on the pressure difference between the detected pressure before the start of injection and the detected Pressure after the end of injection (detected by the injection amount estimating section) and calculating the injection rate waveform based on the estimation result and the previously estimated injection start timing and injection end timing when the injection rate waveform (calculated by the injection rate calculation section). According to this structure, the influence of the detection variation of the maximum waste amount Pβ on the calculation result the gradient waveform can be reduced. Therefore, the injection rate waveform can be (that is, the injection state) is detected with high accuracy become.

According to the above-described aspect of the present invention the fuel pressure sensor is located at a position that is closer to the injection hole as to the pressure accumulator. Accordingly, may change the injection quantity (that is, the injection state) of the actually injected fuel as the fluctuation waveform of the detected pressure, and the injection rate waveform (that is, the injection state) can be detected with high accuracy become. Thus, an innovative detection device for the fuel injection state are created. Therefore, that can Fuel injection system with high accuracy using of the detection result for the controller.

According to In another aspect of the present invention, the detection device for the fuel injection state in a fuel injection system applied, which is capable of a multi-stage injection for a multiple injection of the fuel from the same injector per combustion cycle. The time estimating section for the injection start and the injection end estimates an injection start time and an injection end time of a main injection, whose Injection quantity in the multi-stage injection the largest is. The injection amount estimation section estimates a fuel injection amount per combustion cycle based on the pressure difference between the detected pressure before the beginning of Injecting the first injection stage in the multi-stage injection and the detected pressure after the end of injection of the last one Injection stage in the multi-stage injection from.

The fuel injection state detecting device further includes a non-main injection amount estimating section and a main injection amount estimating section. The non-main injection amount estimating section estimates a fuel injection amount based on the fluctuation waveform of the detected pressure that fluctuates with each injection for each injection stage other than the main injection. The main injection amount estimating section estimates an injection amount of the main injection (for example, Q3 in FIG 7 ) by taking a total of the injection quantity or injection quantities of the injection or injections (for example, Q1 + Q2 + Q4 in FIG 7 ) estimated by the non-main injection amount estimating section is subtracted from the fuel injection amount per combustion cycle estimated by the injection amount estimating section.

Of the Injection rate calculation section calculates a gradient waveform a fuel injection rate of the main injection based on the Injection start time and the injection end time by the time estimating section for the injection start and the end of injection is estimated, and the main injection amount, which is estimated by the main injection amount estimation section.

The other injection amount (Q1, Q2, Q4) other than the main injection amount is less than the total injection amount per combustion cycle. Therefore, the influence of the estimation error is the total amount (Q1 + Q2 + Q4) to the estimation result of the main injection amount low. Estimating the fuel injection amount per combustion cycle becomes executed on the basis of the pressure difference, without the maximum waste amount Pβ is used, which is a high Having detection variation. Therefore, the estimation accuracy can be be improved compared to the case where the fuel injection amount per combustion cycle based on the fluctuation waveform is appreciated. Therefore, the main injection amount (Q3), which is estimated by the total amount (Q1 + Q2 + Q4) the injection amounts of the fuel injection amount per combustion cycle is subtracted, which is estimated in this way, with be estimated with high accuracy.

Consequently becomes the main injection rate waveform on the basis the main injection amount, the injection start timing and the injection end timing, which are estimated with high accuracy. Therefore can the main injection rate waveform (i.e., the injection state) be detected with a high accuracy.

According to Another aspect of the present invention is the fuel pressure sensor attached to the injector. Therefore, the attachment position the fuel pressure sensor closer to the injection hole as in the case where the fuel pressure sensor is attached to a pipe is that connects the accumulator and the injector. Accordingly, the pressure fluctuation at the injection hole be detected more suitably than in the case where the pressure fluctuation is detected after the pressure fluctuation resulting in the injection hole is attenuated in the tube.

According to Another aspect of the present invention is the fuel pressure sensor attached to a fuel inlet of the injector. According to one Another aspect of the present invention is the fuel pressure sensor mounted inside the injector for detecting the fuel pressure in an internal fuel channel extending from a fuel inlet extends to the injection hole of the injector.

Of the Mounting structure of the fuel pressure sensor can be simplified in the case in which the fuel pressure sensor at the fuel inlet is fixed as described above in comparison to the case where the fuel pressure sensor is mounted inside the injector is. When the fuel pressure sensor inside the injector is mounted, the fixing position of the fuel pressure sensor closer to the injection hole than in the case where the Fuel pressure sensor is attached to the fuel inlet. Therefore For example, the pressure fluctuation in the injection hole can be detected more appropriately become.

According to one In turn, another aspect of the present invention is an aperture arranged in a fuel passage extending from the pressure accumulator to a fuel inlet of the injector extends to to dampen the pressure pulsation of the fuel in the pressure accumulator (attenuate), and the fuel pressure sensor is downstream the aperture with respect to a fuel flow direction arranged. When the fuel pressure sensor is upstream the diaphragm is arranged, the fuel pressure sensor detects the Pressure fluctuation after the pressure fluctuation in the injection hole has been attenuated by the aperture. In contrast this is according to the aspect explained above According to the present invention, the fuel pressure sensor downstream arranged the aperture. Accordingly, the pressure fluctuation be detected before the pressure fluctuation weakened by the aperture has been, so the pressure fluctuation in the injection hole is still can be detected more appropriate.

The Features and advantages of the embodiments and also the operating methods and the function of the associated Parts are taken from the detailed description set forth below, the appended claims and the drawings clearly, all of them together a part of the present Sign up form.

1 shows a schematic representation of a fuel injection system with a detection device for the fuel injection state according to a first embodiment of the present invention.

2 Fig. 11 is an inner side view schematically showing an internal structure of an injector used in the system according to the first embodiment.

3 FIG. 12 is a flowchart showing a basic procedure of a fuel injection control process according to the first embodiment. FIG.

4 FIG. 12 is a flowchart showing process procedures of the fuel injection amount detection and the fuel injection rate estimation according to the first embodiment. FIG.

5 Fig. 10 is a timing chart showing a relationship between a fluctuation waveform of the detected pressure and an injection rate waveform during a one-stage injection execution period according to the first embodiment.

6 shows a representation of an example for correcting the injection rate waveform according to the first embodiment.

7 FIG. 12 is a timing chart showing a relationship between a detected pressure waveform fluctuation waveform and an injection rate waveform during a multi-stage injection execution period according to the first embodiment. FIG.

8th FIG. 12 is a timing chart of processes for calculating an injection rate waveform according to a pump overlapping period according to a third embodiment of the present invention. FIG.

below is a fuel injector and a fuel injection system according to the embodiments of the present Invention described with reference to the drawings. The Apparatus of each of the embodiments discussed below is in a common rail type fuel injection system for an internal combustion engine, for example a vehicle with four Wheels, mounted. The device is used when an injection delivery (direct injection delivery) from under high Pressurized fuel (for example, light oil at an injection pressure of 1000 atmospheres or higher) directly into a combustion chamber of a cylinder of a diesel internal combustion engine is performed.

First, referring to 1 the outline of a common rail type fuel injection system (an in-vehicle engine system) according to a first embodiment of the present invention is explained. It is assumed that an internal combustion engine according to the present embodiment is a four-cycle alternating-cycle diesel engine having a plurality of cylinders (for example, four in-line cylinders). In the internal combustion engine, a present target cylinder is sequentially discriminated by a cylinder determination sensor (an electromagnetic pickup) provided on a cam shaft of a suction valve or an exhaust valve. In each of the four cylinders, # 1 to # 4, a combustion cycle consisting of four strokes of an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke, sequentially in the order of the cylinders # 1, # 3, # 4 and # 2 in the cycle of 720 ° crank angle, and more specifically, as the combustion cycles deviate from each other by 180 ° crank angle between the cylinders.

Like this in 1 is shown, the system is generally constructed such that an ECU 30 (a fuel injection control portion) as an electronic control unit receives sensor output signals from various sensors and controls the drive of respective devices constituting a fuel delivery system based on the respective sensor output signals. The ECU 30 sets an amount of supply of an electric current that goes to a suction control valve 1c is supplied, whereby a fuel delivery amount of a fuel pump 11 is controlled to a desired value. Thus, the ECU performs 30 a feedback control (for example, a PID control), so that the fuel pressure in a common rail 12 (an accumulator), ie, a current fuel pressure supplied by a fuel pressure sensor 20a is measured, with a setpoint (target fuel pressure) coincides. The ECU 30 controls a fuel injection quantity for a predetermined cylinder of the target internal combustion engine, and finally, an output of the internal combustion engine (ie, a rotational speed or torque of an output shaft of the internal combustion engine) to desired magnitudes based on the fuel pressure.

The devices that make up the fuel delivery system have the fuel tank 10 , the fuel pump 11 , the common rail 12 and the injectors 20 (Fuel injection valves), which elements are arranged in this order from an upstream fuel flow side. Of these devices are the fuel tank 10 and the fuel pump 11 through a pipe 10a via a fuel filter 10b connected.

The fuel pump 11 consists of a high pressure pump 11a and a low pressure pump 11b through a drive shaft 11d is (are) driven. The fuel pump 11 is constructed such that fuel passing through the low pressure pump 11b from the fuel tank 10 is sucked through the high-pressure pump 11a pressurized and discharged. A fuel pumping amount going to the high pressure pump 11a and finally a fuel delivery amount of the fuel pump 11 be through the suction control valve 11c (SCV) measured at a fuel suction side of the fuel pump 11 is provided. The fuel pump 11 can the fuel delivery amount from the pump 11 to control to a desired value by regulating the driving current (possibly a valve opening degree) of the Saugsteuerventils 11c , For example, the suction control valve 11c a normally-on type regulating valve that opens when de-energized.

The low pressure pump 11b of the two types of pumps that the fuel pump 11 form, for example, constructed as Trochoidlieferpumpe. The high pressure pump 11a For example, it consists of a plunger pump. The high pressure pump 11a is so constructed that it is capable of successively causing the fuel conveyed to pressurizing chambers at a predetermined timing by a reciprocating motion caused in its axial directions by an eccentric cam (not shown, respectively) to pump predetermined plunger (for example, three plunger). Both pumps 11a and 11b be through the drive shaft 11d driven. The drive shaft 11d is with the crankshaft 41 as the output shaft of the target internal combustion engine locks and rotates at a ratio of 1/1, 1/2 or the like with respect to one revolution of the crankshaft 41 , That is, the low pressure pump 11b and the high pressure pump 11a are driven by the output power of the target internal combustion engine.

The fuel passing through the fuel pump 11 from the fuel tank 10 through the fuel filter 10b is sucked in, becomes the common rail 12 fed by pressure (pumped). The common rail 12 stores the fuel coming from the fuel pump 11 has been pumped, at a high pressure condition. The fuel that is in the high-pressure state in the common rail 12 is stored, becomes the injectors 20 the respective cylinder # 1 to # 4 by high-pressure pipes 14 , which are provided on the respective cylinders, distributed and delivered. Fuel delivery holes of the injectors 20 (# 1) to 20 (# 4) are with a pipe 18 connected to the return of excess fuel to the fuel tank 10 serves. A panel 12a (a fuel pulsation reducing portion) is between the common rail 12 and the high pressure pipe 14 provided to attenuate (mitigate) a pressure pulsation of the fuel coming from the common rail 12 to the high pressure pipe 14 flows.

The detailed structure of the injector 20 is in 2 shown. Basically, the four injectors have 20 (# 1) to 20 (# 4) the same structure (for example, the in 2 shown construction). Each injector 20 is an injection device of the hydraulic drive type, the internal combustion engine combustion fuel (ie the fuel in the fuel tank 10 ) used. In the injector 20 For example, the drive energy for injecting the fuel is transmitted through an oil pressure chamber Cd (ie, a control chamber). Like this in 2 4, the injector is constructed as a fuel injection valve of a normally closed type, which is brought into a closed valve state when de-energized.

The high pressure fuel coming from the common rail 12 is conveyed, flows into a fuel inlet 22 in a housing 20e the injection device 20 is formed, and a part of the incoming high-pressure fuel flows into the oil pressure chamber Cd, and the other part of the incoming high-pressure fuel flows to the injection holes 20f , A leak hole 24 is formed in the oil pressure chamber Cd and is controlled by a control valve 23 opened and closed. If the leak hole 24 through the control valve 23 is opened, the fuel in the oil pressure chamber Cd returns to the fuel tank 10 through the fuel delivery hole 21 from the leak hole 24 back.

When the fuel injection through the injector 20 is executed, the control valve 23 according to an excitation state (excitation / de-excitation) of a solenoid 20b operated, which forms a two-way type electromagnetic valve. Thus, a degree of sealing of the oil pressure chamber Cd and finally the pressure in the oil pressure chamber Cd (which is equivalent to the back pressure of a needle valve 20c is) increased / decreased. Due to the increase / decrease in pressure, the needle valve moves 20c inside the case 20e together with or against a tensile force of a spring 20d (a coil spring) (ie, an elastic force of the spring 20d to stretch) back and forth (it moves up and down). Accordingly, a fuel supply channel 25 to the injection holes 20f (a required number of them are drilled) at the middle of the path opened / closed by it (more precisely, on a slanted seat side, at which the needle valve 20c is attached and of which the needle valve 20c separated (lifted) in accordance with the reciprocating movement of the needle valve 20c ).

The drive control of the needle valve 20c is performed by a power on / off control. That is, a pulse signal (an excitation signal) that instructs to turn on / off is received from the ECU 30 to the driving portion (the two-way type electromagnetic valve) of the needle valve 20c Posted. The needle valve 20c lifts and opens the injection holes 20f when the pulse is on (or off) and the needle valve 20c descends to the injection holes 20f to block when the pulse is off (or is on).

The pressure increasing process of the oil pressure chamber Cd is controlled by the fuel supply from the common rail 12 executed. The pressure reducing process of the oil pressure chamber Cd is performed by operating the control valve 23 executed in which the solenoid 20b is stimulated and thus the Le ckageloch 24 opens. Thus, the fuel in the oil pressure chamber Cd returns to the fuel tank 10 through the pipe 18 (this in 1 shown), with the tube 18 the injector 20 and the fuel tank 10 combines. That is, the operation of the needle valve 20c that the injection holes 20f opens and closes, is controlled by the fuel pressure in the oil pressure chamber 10d by the opening operation and closing operation of the control valve 23 is set.

Thus, the injector 20 the needle valve 20c which opens a valve and valve closing the injector 20 performs by the fuel supply duct 25 that goes to the injection holes 20f extends, is opened and closed by a predetermined reciprocating operation inside the valve body (ie the housing 20e ). In a non-driven state, the needle valve 20c in a valve closing direction by the force (ie, the stretching force of the spring 20b ), always on the needle valve 20c is applied in the valve closing direction. In a powered state is on the needle valve 20c a driving force applied so that the needle valve 20c in a valve opening direction against the stretching force of the spring 20d is offset. The lifting amount of the needle valve 20c changes substantially symmetrically between the non-driven state and the driven state.

A fuel pressure sensor 20a (see also 1 ) for detecting the fuel pressure is at the injector 20 attached. The fuel inlet 22 in the case 20e is formed, and the high pressure pipe 14 are through a clamping device 20j connected, and the fuel pressure sensor 20a is at the clamping device 20j attached. Thus, by the fuel pressure sensor 20a at the fuel inlet 22 the injection device 20 is fixed, the fuel pressure (the intake pressure) at the fuel inlet 22 be recorded at any time. More specifically, a fluctuation waveform of the fuel pressure, which is an injection operation of the injector 20 accompanied by a fuel pressure level (ie, a stable pressure), a fuel injection pressure, and the like by the output signal of the fuel pressure sensor 20a recorded (measured).

The fuel pressure sensors 20a are respectively on the plurality of injectors 20 (# 1) to 20 (# 4) intended. The fluctuation waveform of the fuel pressure, the injection process of the injector 20 accompanied with a predetermined injection can with high accuracy on the basis of the output signals of the fuel pressure sensors 20a (as explained in more detail below).

In addition to the sensors described above, various sensors are provided for vehicle control in a vehicle (for example, a four-wheeled passenger car, a truck, or the like, not shown). For example, a crank angle sensor 42 (For example, an electromagnetic pickup), which outputs a crank angle signal at each predetermined crank angle (for example, in a cycle of 30 ° crank angle), on an outer circumference of the crankshaft 41 as the output shaft of the target internal combustion engine provided to a rotational angular position of the crankshaft 41 , a speed of the crankshaft 41 (ie, a rotational speed of the engine) and the like. An accelerator pedal sensor 44 That outputs an electric signal corresponding to a state (ie, an offset amount) of an accelerator pedal is provided to detect an operation amount ACCP (ie, a depression amount) of the accelerator pedal caused by the driver.

In such a system, it is the ECU 30 , which functions as the fuel injection control section according to the present embodiment and that mainly executes the engine control as the electronic control unit. The ECU 30 (an engine control ECU) has a known microcomputer (not shown). The ECU 30 recognizes the operating state of the target internal combustion engine and the requirements (commands) of a user on the basis of the detection signals of the various sensors described above. The ECU 30 performs various kinds of control with respect to the above-described internal combustion engine in the optimum modes according to the respective situation at any time by operating the various actuators, such as the above-described suction control valve 11c and the injectors 20 according to the operating state of the target internal combustion engine and the requirements of the user (driver).

The microcomputer operating in the ECU 30 is composed of a CPU (a basic process unit) for executing various kinds of calculations, a RAM as a main memory for temporarily storing data in the calculation process, results of calculation and the like, a ROM as a program memory, an EEPROM as a memory for Data storage, a backup RAM (a memory that is invariably supplied with power from a backup power source, such as an in-vehicle battery, even after the main power supply of the ECU 30 has been stopped) and the like. Various types of programs, control tables (control assignments), and the like that use the Ver Engine control including the program relating to the fuel injection control has previously been stored in the ROM, and the various types of control data including the design data of the target engine have previously been stored in the memory for data storage (for example, the EEPROM).

In the present embodiment, the ECU calculates 30 a moment (a request torque) currently present in the output shaft (the crankshaft 41 ), and finally, a fuel injection amount satisfying the request torque based on the various types of successively input sensor output signals (detection signals). Thus, the ECU 30 variably the fuel injection amount of the injector 20 to obtain the moment (generation torque) generated by the fuel combustion in each cylinder (a combustion chamber) and the shaft torque (output torque) actually to the output shaft (the crankshaft 41 ) is to be controlled. That is, the ECU 30 Controls the generation torque or the shaft torque to the request torque (command torque).

That is, for example, the ECU calculates 30 the fuel injection amount according to the engine operation state, the operation amount of the accelerator pedal caused by the driver, and the like at each time point, and outputs an injection control signal (an injection command signal) to command the fuel injection with the calculated fuel injection amount to the injector 20 synchronous with a desired injection timing. Thus, that is, based on a driving amount of the injector 20 (For example, a valve opening period), the output torque of the target engine is controlled to the target value.

As As is known, in an internal combustion engine, an intake throttle valve (a throttle), which is in an intake passage of the internal combustion engine is provided at a substantially completely open Condition during steady operation for the purpose of Increasing an amount of fresh air, reducing a pumping loss and like that, kept. Therefore, the control of the fuel injection amount a main portion of the combustion control (more specifically, the Combustion control regarding the torque setting) during of continuous operation.

Hereinafter, a basic process procedure of the fuel injection control according to the present embodiment will be described with reference to FIG 3 explained. The values of the various parameters used in the 3 The process shown in FIG. 1 is used at any time in the memory device included in the ECU 30 are mounted, such as the RAM, the EEPROM or the backup RAM, stored and updated at any time that this is required (Update). Basically, the ECU performs 30 the programs stored in the ROM to carry out the process indicated by the flowchart of FIG 3 is shown.

Like this in 3 First, at step S11, in a series of processes, predetermined parameters, such as the current engine speed (ie, an actual measured value detected by the crank angle sensor 42 is measured) and the fuel pressure (ie, an actual reading taken by the fuel pressure sensor 20a is measured), and also the accelerator pedal operation amount ACCP (ie, an actual measurement value detected by the accelerator pedal sensor 44 is measured) read by the driver at this time and the like.

In the following step S12, an injection pattern is set on the basis of the various parameters read in step S11. For example, in the case of a single-stage injection, an injection amount Q (injection period) of the injection is variably set in accordance with the torque generated by the output shaft (the crankshaft 41 ), that is, the request torque (command torque) calculated by the accelerator pedal operation amount ACCP and which is equal to the engine load at that time. In the case of an injection pattern of a multi-stage injection, a total injection amount Q (a total injection period) of the injections contributing to the torque is variably set in accordance with the torque applied to the output shaft (the crankshaft 41 ), ie the request torque (command torque).

The Injection pattern is based on a predetermined table or assignment (an injection control table or a mathematical Expression) and a correction coefficient stored in the ROM, for example obtained. More specifically, the optimal injection pattern (adaptation values) previously by trial and the like in previously suspected areas the predetermined parameter (read at step S11) and, for example written in the injection control table.

For example, the injection pattern is defined by such parameters as, for example, the number of injection stages (ie, the frequency injections performed in one injection cycle), the injection timing of each injection (ie, the injection time), and the injection period (equivalent to the injection amount) of each injection. Thus, the injection control map or injection control table described above shows the relationship between the parameters and the optimum injection pattern.

The injection pattern obtained based on the injection control table is stored by the correction coefficient (stored in, for example, the EEPROM in the ECU 30 ), which is brought up to date separately (update), corrected. For example, a set value is calculated by dividing the table value by the correction coefficient. Thus, the injection pattern of the injection to be executed at that time and, finally, the injection command signal to the injector become 20 obtained according to the injection pattern. The correction coefficient (more specifically, a predetermined coefficient of the plurality of types of coefficients) is successively updated by separately treating during operation of the internal combustion engine (update).

If the injection pattern is set (at step S12) Tables individually for each element of the Injection pattern (such as the number the injection stages) can be used. Alternatively, tables, each of which for some summarized elements of the Injection pattern is designed, or a table for all Elements of the injection pattern, to be used.

The thus-determined injection pattern or the final command value (the injection command signal) corresponding to the injection pattern is used in the following step S13. That is, in step S13 (a command signal output section), the drive of the injector 20 is controlled on the basis of the command value (the injection command signal), or more specifically, by outputting the injection command signal to the injector 20 , After the drive control of the injector 20 ends the sequence of in 3 shown processes.

The following is a process for detecting a fuel injection amount of the injector 20 and estimating a fuel injection rate thereof with reference to FIG 4 explained. A sequence of processes in 4 are executed in a predetermined cycle (for example, a calculation cycle executed by the above-described CPU) or at a predetermined degree of crank angle. The ECU 30 that performs the process is equivalent to a detection device for the fuel injection state.

First, at the step S21, the output value (the detected pressure P) of the fuel pressure sensor becomes 20a obtained. This process for obtaining the output value becomes for each of the plurality of fuel pressure sensors 20a executed. Hereinafter, the obtaining process of the output value at the step S21 will be described in detail with reference to FIG 5 explained.

Section (a) of 5 shows the injection command signal INJ flowing to the injector 20 at step S13 of FIG 3 is delivered. The solenoid 20b is operated by turning on a pulse (ie, pulse turning on) of the command signal INJ, and thus the injection holes become 20f open. That is, an injection start is commanded at a pulse on time t1 of the injection command signal INJ, and an injection end is commanded at a pulse off time t2. Therefore, the injection amount Q is controlled by a valve opening period Tq of the injection holes 20f is controlled with a pulse-on period of the command signal INJ (ie, an injection command period). Section (b) of 5 FIG. 12 shows a change of a fuel injection rate R of the fuel from the injection holes. FIG 20f which is effected in conjunction with the injection command described above. Section (c) of 5 shows a change (a fluctuation waveform) of the output value (the detected pressure P) of the fuel pressure sensor 20a , caused by the change of the injection rate R.

The ECU 30 detects the output value of the fuel pressure sensor 20a through a subroutine, ie a process that depends on the process of 4 is separate. The ECU 30 successively obtains the output value of the fuel pressure sensor 20a by the subroutine process at an interval that is sufficiently short to ablate the profile of the pressure waveform waveform with the sensor output signal, that is, an interval shorter than the process cycle of 4 is. An example profile is in section (c) of 5 shown. For example, the sensor output signal is successively acquired at an interval shorter than 50 microseconds (or, more preferably, 20 microseconds).

A gradient waveform of the injection rate R can be estimated from the fluctuation waveform of the detected pressure P since a correlation between the fluctuation of the pressure P produced by the fuel pressure sensor 20a is detected, and the change in the injection rate R is, as explained below. That is, after the time t1 at which the injection start command is issued, as shown in the section (a) of FIG 5 is shown, the injection rate R starts increasing at the time point R1, and the injection is started. When the injection rate R starts increasing at the time point R1, the detected pressure P starts decreasing at its change point P1. Thereafter, when the injection rate R reaches the maximum injection rate at the time point R2, the decrease of the detected pressure P stops at a change point P2. Thereafter, when the injection rate R begins to decrease at the time point R2, the detected pressure P starts to increase at the change point P2. Thereafter, when the injection rate R becomes zero and the actual injection ends at the timing R, the increase of the detected pressure P at a change point P3 stops.

Thus, the increase start timing R1 (timing of actual start of injection) and the decrease end timing R3 (timing of actual end of injection) of the injection rate R can be estimated by detecting the change points P1 and P2 in the fluctuation of the detected pressure P detected by the fuel pressure sensor 20a is detected. Moreover, the change of the injection rate R from the fluctuation of the detected pressure P can be estimated on the basis of the correlation between the fluctuation of the detected pressure P and the change in the injection rate R, as explained below.

That is, there is a correlation between a pressure decrease rate Pα from the change point P1 to the change point P2 of the detected pressure P and an injection rate increase rate Rα from the change point R1 to the change point R2 of the injection rate R. There is a correlation between a pressure increase rate Pγ of FIG the change point P2 to the change point P3 and an injection rate reduction rate Rγ from the change point R2 to the change point R3. There is a correlation between a pressure decrease amount Pβ (the maximum waste amount) from the change point P1 to the change point P2 and an injection rate increase amount Rβ from the change point R1 to the change point R2. Accordingly, the injection rate rate Rα, the injection rate decrease rate Rγ, and the injection rate decrease amount Rβ of the injection rate R can be estimated by detecting the pressure decrease rate Pα, the pressure increase rate Pγ, and the pressure decrease amount Pβ from the fluctuation of the detected pressure P detected by the fuel pressure sensor 20a is detected. As described above, the various states R1, R3, Rα, Rβ and Rγ of the injection rate R can be estimated, and finally, the change (the gradient waveform) of the fuel injection rate R can be estimated as shown in the section (b) of FIG 5 is shown.

An integration value of the injection rate R from the actual injection start to the actual injection end (ie, a hatched area indicated by the mark S in the section (b) of FIG 5 an integration value of the pressure P in a portion of the fluctuation waveform of the detected pressure P, the change of the injection rate R from the actual injection start to the actual injection end (ie, a portion from the change point P1 to the point of change P3) is correlated with the integration value S of the injection rate R. Therefore, the injection rate integration value S equivalent to the injection quantity Q can be estimated by calculating the pressure integration value from the fluctuation of the detected pressure P detected by the fuel pressure sensor 20a is detected.

In 4 is the process content of the steps S22 to S28 following the step S21, different between the case where the multi-stage injection is executed and the case where the single-stage injection is executed. Hereinafter, first, the process content in the case where the single-stage injection is executed will be explained with reference to FIG 5 and after that, the process content in the case where the multi-stage injection is executed will be explained with reference to FIG 7 explained. In the subsequent steps S22 to S28, the fluctuation waveform generated by the fuel pressure sensor becomes 20a is detected according to an injection cylinder of the plurality of cylinders in which injection and non-injection are successively performed in each of them. The injection cylinder is a cylinder in which injection is currently being performed.

Because the plunger pump as the high pressure pump 11a as mentioned above, a pulsation due to the pumping is caused in the pressure of the fuel coming from the high-pressure pump 11a to the common rail 12 is pumped. In the present embodiment, the process of the subsequent steps S22 to S28 is executed by the fluctuation waveform which is obtained when a fuel pumping period for pumping the fuel from the high-pressure pump 11a to the common rail 12 not with the fuel injection period of the fuel injection from the injection holes 20f covered by the fluctuation waveforms used with the respective fuel pressure sensors 20a be obtained.

In step S22, which is at the vorste Following the step S21 described above, the timings at which the change points P1 and P3 occur are detected on the basis of the fluctuation waveform obtained at the step S21. More specifically, preferably, a differential value of the first order of the fluctuation waveform is calculated, and the occurrence of the change point P1 is detected when the differential value exceeds a threshold at the first time after the pulse ON timing t1 of the injection command INJ. Moreover, in the case where a stable state results after the occurrence of the change point P1, it is preferable to detect the occurrence of the change point P3 when the differential value falls below the limit value the first time before the stable state results. The stable state is a state where the differential value fluctuates within a range of the limit value.

at the subsequent step S23 becomes a pressure reduction amount Pβ on the basis of the fluctuation waveform obtained in the step S21 detected. For example, the pressure reduction amount Pβ is detected by detecting the detected pressure P at the point of change P1 of FIG a peak value of the detected pressure P between the point of change P1 and the change point P3 of the fluctuation waveform is subtracted.

In the subsequent step S24 (an injection rate calculation section), the increase start timing R1 (actual injection start timing) and the decrease end timing R3 (actual injection end timing) of the injection rate R are estimated on the basis of the detection results P1, P3 of the step S22 , Moreover, the injection rate increase amount Rβ is estimated on the basis of the detection result Pβ of the step S23. Then, a course waveform of the injection rate R obtained in the section (b) of FIG 5 is calculated based at least on the estimated values R1, R3, Rβ. The values R2, Rα, Rγ, and the like may be estimated in addition to the estimated values R1, R3, Rβ, and may be used to calculate the injection rate waveform.

at the subsequent step S25 (a first injection amount estimating section) the range S is calculated by integrating the injection rate waveform which has been calculated at step S24 is, and in an interval from R1 to R3. The area (area) S is considered a first estimated value of the injection amount Q used.

at the following step S26 (a second injection amount estimating section) is the pressure difference ΔP between the detected pressure P before the start of the injection and the detected pressure P after the end of the injection on the basis of the fluctuation waveform of the detected pressure P obtained in step S21 is. For example, the pressure difference ΔP between the detected pressure P at the injection start command timing t1, which is commanded by the injection command signal INJ, and the detected pressure P at the injection start command timing t3, the by the injection command signal INJ regarding the next one Injection is commanded, recorded. After that, the injection quantity (a second estimated value) based on the pressure difference ΔP calculated. For example, the injection quantity is calculated by the pressure difference ΔP with a predetermined coefficient K is multiplied.

In the subsequent step S27 (an injection amount calculating section) will be the injection rate that will eventually for the Control is used, based on the first estimate, calculated at step S25 and the second estimated value, calculated in step S26 is calculated. For example becomes a difference between the first estimate and the second estimate as an estimation error of the first estimate, and the first estimate is corrected according to this difference. For example a correction value is calculated by subtracting the difference with a predetermined coefficients (preferably, a value that is smaller is multiplied by 1), and the correction is performed by the correction value is added to the first estimate. Alternatively, an average value of the first and second estimates is used as the injection amount as the final detection result.

At the subsequent step S28 (an injection rate correcting section), the course waveform of the injection rate R calculated at the step S24 is corrected on the basis of the injection amount calculated at the step S27. For example, the injection rate waveform calculated at step S24 is corrected so that the range S (the first estimated value) calculated at step S25 coincides with the injection quantity calculated at step S27. Specifically, as mentioned above, the variation in the maximum drop amount Pβ of the detected value of the detected pressure P is high. Therefore, it is desirable to correct the history waveform so that the injection amount agrees with the corrected injection amount by correcting the injection rate increasing amount Rβ. For example, if the injection rate waveform calculated is as indicated by a solid line L1 in the section (b) of FIG 6 shown is corrected so that the injection amount increases, it is desirable to carry out the correction to increase the injection rate increasing amount Rβ as indicated by a broken line L2 in the section (b) of FIG 6 is shown.

Alternatively, the course waveform may be corrected so that the injection amount agrees with the corrected injection amount by correcting a hold time of the injection rate peak value R2 as indicated by a dot-and-dash line L3 in the section (b) of FIG 6 is shown. Alternatively, the course waveform may be corrected so that the injection amount agrees with the corrected injection amount by correcting both the injection rate increasing amount Rβ and the holding time of the peak value R2, as indicated by a broken line L4 in the section (b) of FIG 6 is shown. The detection accuracy of the change points P1 and P3 of the detected pressure P is higher than the detection accuracy of the maximum decrease amount Pβ, therefore, preferably, the actual injection start timing R1 and the actual injection end timing R3 are not corrected.

Thus, the sequence of processes ends 4 , The fuel injection amount corrected in step S27 and the injection rate waveform corrected in step S28 are used to, for example, those in step S12 of FIG 3 to update the above-described injection control table (ie, learning).

The fluctuation waveform of the detected pressure P in the case of the single-stage injection is given in a mode described in the section (c) of FIG 5 is shown. A fluctuation waveform of the detected pressure P in the case of the multi-stage injection is given in a mode described in the section (c) of FIG 7 For example, shown. In an in 7 As shown, a pilot injection, a pilot injection, a main injection, and a post-injection are sequentially performed during a combustion cycle. With P11, P21, P31 and P41 are in the section (c) of 7 Points of change that result in the fluctuation waveform associated with the start of combustion of the respective injection stages are shown. With P12, P22, P32 and P42, pressure drop peak points of the respective injection stages are shown. P13, P23, P33 and P43 show change points that result in the fluctuation waveform associated with the injection end of the respective injection stages. The hatched areas S1, S2, S3 and S4 shown in the section (b) of FIG

7 are shown, correspond to the injection quantities Q1, Q2, Q3 and Q4 of the respective injection stages.

In the case of multi-stage injection, which in 7 is shown, at step S22, the appearance timings of the change points P11, P13, P21, P23, P31, P33, P41 and P43 of the respective injection stages are obtained from the fluctuation waveform obtained at step S21 by the same method as in the case the single stage injection detected. In the subsequent step S23, the pressure drop amounts Pβ1, Pβ2, Pβ3, Pβ4 of the respective injection stages from the fluctuation waveform obtained at the step S21 are detected by the same method as in the case of the single-stage injection. At the following step S24, the course waveform for the injection rate R becomes as shown in the section (b) of FIG 7 is calculated for each injection stage based on the detection results of steps S22 and S23.

In In the following step S25, the injection quantities Q1 to Q4 of FIG estimated injection levels by the areas S1 to S4 of the respective injection stages are calculated by the same procedure as in the case of single stage injection based on the injection rate waveform at calculated in step S24. The main injection quantity Q3 of the estimated injection quantities Q1 to Q4 corresponds to the first Estimate.

In In the following step S26, the pressure difference ΔP between the detected pressure P before the start of the injection and the detected pressure P after the end of injection based on the fluctuation waveform of the detected pressure P obtained in step S21 becomes. More specifically, the pressure difference ΔP is between the detected pressure P at the pilot injection start command timing t11 commanded by the injection command signal INJ, and the detected pressure P at the injection start command timing t51; the next by the injection command signal INJ Injection is commanded, recorded. Then, a total injection amount, which is injected per combustion cycle on the basis the pressure difference ΔP calculated. For example, the Total injection amount calculated by the pressure difference ΔP is multiplied by a predetermined coefficient K.

Further, at the step S26 (a main injection amount estimating section), an injection amount Q3 of the main injection is estimated by subtracting the sum Q1 + Q2 + Q4 of the injection amounts of the other injections other than the main injection estimated at the step S25 from the total injection amount calculated on the basis of the pressure difference ΔP becomes as described above. The thus estimated main injection amount Q3 corresponds to the second estimated value.

In In the following step S27, the control finally becomes used main injection amount based on the first estimate, the calculated at step S25 and the second estimated value, calculated at step S26 by the same method as calculated in the case of single stage injection. At the following Step S28 becomes a part of the course waveform of the injection rate R calculated in step S24 corresponding to the main injection by the same method as in the case of single-stage injection based on the main injection amount, which is at step S27 is calculated, corrected.

In the present embodiment, the fuel pressure sensor 20a arranged at a position that is closer to the injection holes 20f as to the common rail 12 located. Accordingly, the pressure fluctuation in the injection holes 20f be detected before the pressure fluctuation inside the common rail 12 is dampened. Accordingly, the change of the actual injection amount can be detected with high accuracy as the fluctuation waveform of the detected pressure. Accordingly, the fuel injection amount may be estimated based on the detected fluctuation waveform (by the first injection amount estimating section: S25), and the fuel injection amount may be estimated based on the pressure difference ΔP of the detected pressure P before and after the injection start (by the second injection amount estimating section: S26) ,

According to In the present embodiment, the injection amount Q by two kinds of different methods S25 and S26 in this Way estimated, and the injection quantity is based of the obtained first and second estimates. Therefore, compared to the case where the injection amount based on just one of the estimated results is calculated, the influence of the detection variation (detection fluctuation) of the maximum amount of waste Pβ, which will be a problem then can be reduced when the injection amount is large. Therefore, the injection amount can be detected with high accuracy, and finally, the injection rate waveform with a high accuracy based on the injection quantity be captured in this way with a high accuracy is detected.

According to the present embodiment, the process of steps S22 to S28 of FIG 4 by using the fluctuation waveform obtained during a non-overlap period in which the fuel pumping period is for pumping the fuel from the high pressure pump 11a to the common rail 12 not with the fuel injection period for injecting the fuel from the injection holes 20f covered. Therefore, the estimation of the injection rate waveform can be performed on the basis of the detected pressure to which a component (disturbance) due to the fuel pumping is not added. Finally, the estimation accuracy can be improved.

According to In the present embodiment, the pressure difference ΔP between the detected pressure P at the injection start command timing t1 and the detected pressure P at the injection start command timing t3 of the next injection as the pressure difference ΔP used by the second injection quantity estimation section S26 is used. The pulsation of the detected pressure P is low and the detected pressure P is stable at the times t1 and t3. Therefore, the pressure difference .DELTA.P, by the second Injection amount estimation section S26 is used with be achieved with high accuracy. Finally, can the estimation by the second injection amount estimating section S26 be executed with high accuracy.

According to the present embodiment, the fuel pressure sensor 20a at the injector 20 attached. Therefore, the fixing position of the fuel pressure sensor 20a closer to the injection holes 20f as in the case where the fuel pressure sensor 20a on the high pressure pipe 14 attached, which is the common rail 12 and the injector 20 combines. Accordingly, the pressure fluctuation at the injection holes 20f be detected more appropriately than in the case where the pressure fluctuation is detected after the pressure fluctuation occurring in the injection holes 20f occurs in the high pressure pipe 14 has been weakened.

In the first embodiment described above, the injection amount Q is estimated by the two types of different methods S25 and S26, and the course waveform of the injection rate R is calculated using the injection amount calculated based on the first and second estimates. In contrast, in a second embodiment of the present invention described below, one of the estimation methods is omitted, and the course waveform of the injection rate R is calculated based on the estimation value of the other estimation method. The following is both the case of the individual stages injection and as well as the multi-stage injection explained in detail.

In the present embodiment, the same process as in the processes of steps S21 and S22 of FIG 4 (an injection start timing and injection end timing estimating section) are executed to first estimate the appearance timings (occurrence timings) of the change points P1 and P3 (ie, the injection start timing R1 and the injection end timing R3). Then the same process as the process of step S26, in 4 is shown (an injection amount estimating section) executed to estimate the fuel injection amount Q on the basis of the pressure difference ΔP as shown in FIG 5 is shown.

Then is the course waveform of the fuel injection rate R (by an injection rate calculating section) on the basis of Injection start timing R1, the injection end timing R3 and the fuel injection amount Q, which by the above-mentioned Process is obtained, calculated. For example, the injection rate R calculated by the injection amount Q by the fuel injection period is divided from R1 to R3, and the gradient waveform becomes so calculates that the injection rate R during the fuel injection period remains at the injection rate R, by the above-mentioned Dividing has been obtained. The gradient waveform shapes in this case in a waveform with a right-angled Form in which the injection rate R remains at the injection rate passing through calculating the above-mentioned dividing, and from the injection start timing R1 to the injection end timing R3.

Alternatively, the gradient waveform may be calculated such that the injection rate R obtained by the above-mentioned dividing serves as the peak value. The tracking waveform of this case becomes a waveform in a manner similar to the waveform used in the portion (b) of FIG 5 is shown, in which the injection rate R performs a course in a period from the injection start timing R1 to the injection end timing R3 such that the injection rate calculated by the above-mentioned dividing is a peak value in the period.

When the multi-stage injection is carried out, the injection start timing and the injection end timing of each injection stage are estimated by the same process as in the processes of steps S21 and S22 of FIG 4 is performed. Then, the same process as in the process of step S26 in FIG 4 in order to estimate the total injection amount injected per combustion cycle on the basis of the pressure difference ΔP, as shown in the section (c) of FIG 7 is shown.

Then, the same process as in the processes of steps S23 and S24 of FIG 4 for any other injection stage, except for the main injection, to calculate the injection rate waveform for each injection stage other than the main injection. Then, the areas S1, S2, and S4 concerning the respective other injection stages other than the main injection are calculated based on the estimated course waveforms. That is, the respective injection amounts Q1, Q2, and Q4 of the other injections other than the main injection are calculated (by a non-main injection amount estimating portion). Then, the injection amount Q3 of the main injection (by a main injection amount estimating section) is estimated by subtracting the sum Q1 + Q2 + Q4 of the calculated values from the total injection amount calculated based on the pressure difference ΔP.

Then the course waveform of the main fuel injection rate goes through the same procedure as in the case of single stage injection based on the main injection start timing, the main injection end timing and the main injection amount Q3 caused by the above-mentioned Treatment is obtained, calculated. Thus, effects, similar to the first embodiment are achieved, even in the present embodiment become.

In the first embodiment described above, the process of steps S22 to S28 of FIG 4 by using the fluctuation waveform obtained during a non-overlapping period when the fuel pumping period is for pumping the fuel from the high-pressure pump 11a to the common rail 12 not with the fuel injection period for injecting the fuel from the injection holes 20f covered. In contrast, a third embodiment of the present invention described below aims at performing calculation of the injection rate waveform during an overlap period in addition to calculating the injection rate waveform during the non-overlap period.

Hereinafter, a process of calculating the injection rate waveform during the pump overlap period realized by the present embodiment will be described with reference to FIG 8th explained. In 8th the section (a) shows a course of the injection command signal INJ to the injector 20 , shows the section (b) a course of the injection rate R, the portion (c) shows a curve of the detected pressure P of the fuel pressure sensor 20a concerning an injection cylinder in which fuel injection is currently being performed (ie, a fluctuation waveform during an injection pumping period in which injection is performed during pumping), the portion (d) shows a trace of the detected pressure P of the fuel pressure sensor 20a concerning a non-injection cylinder in which fuel injection is not currently performed (ie, a fluctuation waveform during a non-injection pumping period in which injection is not performed during pumping), and section (e) shows a pressure value equivalent to a pump pumping component is.

The fluctuation waveforms shown by dashed-dotted lines L11 and L13 in sections (c) and (d) of FIG 8th The graphs of the fuel pressure in the case where no influence of the pump pumping component is exerted (ie, in the case where the pumping component is zero) are shown. The in the section (c) of 8th The fluctuation waveform L10 shown during the injection pumping period is a waveform in the case where the fuel injection by the injector 20 and fuel pumping through the fuel pump 11 be executed in a overlapping manner. The fluctuation waveform L10 shown in the section (c) of FIG 8th 1 is a waveform that is designed by combining a decreasing component of the detected pressure P caused in connection with the fuel injection (ie, a component shown by the dashed-dotted line L11) and the increasing component that is in communication is effected with the fuel pumping (ie a component which increases in connection with the pumping component, which in the section (e) of 8th is shown). The fluctuation waveform during the non-injection pumping period indicated by the solid line L12 in the section (d) of FIG 8th is a waveform in which only the increase component resulting in connection with the fuel pumping (ie, a component that increases in conjunction with the pumping component shown in the section (e) of FIG 8th shown) occurs because the injector 20 in the non-injection state.

In the present embodiment, the fluctuation waveform (ie, the waveform shown by the solid line L <b> 12) becomes the pump pumping component that is in the detected pressure P of the fuel pressure sensor 20a corresponding to the non-injection cylinder, obtained first (by a pump fluctuation waveshaper length section). Then, the fluctuation waveform (ie, the waveform shown by the solid line L10) of the detected pressure P of the fuel pressure sensor becomes 20a corresponding to the injection cylinder during the overlap period (overlap period) in which the fuel pumping period overlaps with the fuel injection period.

Then, the fluctuation waveform shown by the chain line L11 is calculated by the fluctuation waveform L12 (ie, the pump pumping component) of the fuel pressure sensor 20a corresponding to the non-injection cylinder is subtracted from the obtained fluctuation waveform L10. In the case where a plurality of fuel pressure sensors 20a which correspond to the non-injection cylinder (non-injection cylinders) may have an average value of the fluctuation waveforms of the respective fuel pressure sensors 20a , which correspond to the non-injection cylinder (non-injection cylinders), and the fluctuation waveform L11 can be calculated by subtracting the waveform from the fluctuation waveform L10 based on the average value. Then, the process of steps S22 to S28 of FIG 4 using the fluctuation waveform L11 calculated in this manner. Thus, the injection rate waveform during the pump overlap period (see section (b) of FIG 8th ) be calculated.

The Embodiments described above can for example, modified and executed as follows. In addition, the present invention is not on limited the embodiments described above. Characteristic structures of the respective embodiments can be combined arbitrarily.

In the above-described first embodiment, the pressure difference ΔP between the injection start command timing t1 (t11) and the injection start command timing t3 (t51) of the next injection is used in the estimation by the second injection amount estimation section S26. Alternatively, the pressure difference between a start time and an end time of a range Tb in which the injection is possible (a crank angle at which the injection is possible) and the in 7 is used for the estimation. Alternatively, the pressure difference between the occurrence time of the change point P1 (P11) and the occurrence time of the change point P3 (P43) may be used for the estimation.

In the first embodiment described above, the fluctuation waveform obtained during the non-overlap period (non-blanking period) in which the Fuel pumping period does not overlap with the injection period, as the fluctuation waveform used in steps S22 to S28 of 4 is used. Alternatively, in the case where a pressure reducing valve in a high pressure fuel delivery passage such as the common rail 12 is provided, the fluctuation waveform, which is obtained during a pressure reduction valve non-operation period in which the pressure reduction is performed by the operation of the pressure-reducing valve is not performed in the non-overlapping period. According to this construction, the estimation of the injection rate waveform can be performed on the basis of the detected pressure to which no pressure reducing component (ie, a fault) due to the operation of the pressure reducing valve is added. Accordingly, the estimation accuracy can be improved.

To the fuel pressure sensor 20a at the injector 20 to fix, in the above-described embodiments, the fuel pressure sensor 20a at the fuel inlet 22 the injection device 20 attached. Alternatively, as shown by a dashed line 200a in 2 shown is a pressure sensor 200a inside the case 20e be mounted, and the fuel pressure in the internal fuel channel 25 that is different from the fuel inlet 22 to the injection holes 20f extends can be detected.

The mounting structure of the fuel pressure sensor 20a is easier in the case where the pressure sensor 20a at the fuel inlet 22 is fixed as described above, as in the case where the pressure sensor 200a inside the case 20e is mounted. When the fuel pressure sensor 200a inside the case 20e is mounted, the fixing position of the fuel pressure sensor 200a closer to the injection holes 20f as in the case where the fuel pressure sensor 20a at the fuel inlet 22 is attached. Therefore, the pressure fluctuation in the injection holes 20f be detected even more suitable.

The fuel pressure sensor 20a can on the high pressure pipe 14 be attached. In this case, it is preferable to use the fuel pressure sensor 20a to be fastened to a position by the common rail 12 is spaced by a predetermined distance.

A flow rate limiting section may be provided between the common rail 12 and the high pressure pipe 14 be provided to the flow rate of the common rail 12 to the high pressure pipe 14 limit the flow of fuel. The flow rate limiting portion functions to block the flow passage when leakage of excess fuel through fuel leakage due to damage of the high pressure pipe 14 , the injector 20 or the like is effected. For example, the flow rate limiting portion may be formed of a valve member, such as a ball, which blocks the fuel passage when an excessive flow rate occurs. Alternatively, a flow damper can be picked up, which is formed by the aperture 12a (the fuel pulsation reduction section) and the flow rate limiting section are integrally combined.

In addition to the structure for arranging the fuel pressure sensor 20a downstream of the orifice and the flow rate limiting portion with respect to the fuel flow direction, the fuel pressure sensor 20a downstream of at least one of the aperture and the fuel flow rate limiting portion.

Any number of fuel pressure sensor (s) 20a can be used. For example, two or more sensors 20a be provided on the fuel flow channel of a cylinder. A common rail pressure sensor for detecting the pressure in the common rail 12 may be in addition to the fuel pressure sensor described above 20a be provided.

Instead of in 2 shown injection device 20 with electromagnetic drive, a piezoelectric injector can be used. Alternatively, an injector that does not allow pressure leakage from the leak hole 24 and the like, such as a direct-acting injector that does not transmit the driving power through the oil pressure chamber Cd (for example, a direct-acting piezo injector that has been developed in recent years), also causes. In the case where a direct-acting injector is used, the control of the injection rate is facilitated.

The Type and system structure of the internal combustion engine as the control target element, can also be arbitrary according to the use and the like are modified. In each of the above Embodiments are included in the present invention a diesel engine has been used as an example. in principle For example, the present invention may also be applied to a gasoline engine with spark ignition (more precisely, a direct injection internal combustion engine) or the like are basically applied in the same way become.

For example, a fuel injection system of a direct injection gasoline engine generally has a delivery pipe in which fuel (gasoline or gasoline) is stored in a high pressure state. In the system, the fuel is pumped from a fuel pump to the delivery pipe, and the high pressure fuel in the delivery pipe becomes the plurality of injectors 20 distributed and injected into the combustion chambers of the internal combustion engine and delivered. In this system, the delivery pipe corresponds to the accumulator. The apparatus and the system according to the present invention can be applied not only to the injector which injects the fuel directly into the cylinder but also to an injector which injects the fuel into an intake passage or an exhaust passage.

The The present invention is not intended to cover the disclosed embodiments it can be limited but in many other ways without departing from the scope of the invention, which is defined in the appended claims.

The fuel injection state detecting device has a first injection amount estimating section S25 for estimating a fuel injection amount based on a fluctuation waveform generated by a fuel pressure sensor 20a and a second injection amount estimating section S26 for estimating a fuel injection amount based on a pressure difference ΔP before and after an injection start from a detected pressure detected by the fuel pressure sensor 20a is detected. The apparatus calculates an injection amount based on both estimation values estimated by the two different types of methods S25, S26. Accordingly, an influence of detecting a variation of the maximum waste amount can be reduced as compared with the case where only one of the estimation results is used. Thus, the injection amount can be detected with high accuracy, and finally, a history waveform of an injection rate can be detected accurately on the basis of the accurately detected injection amount.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - JP 2006-200378 A [0002]

Claims (16)

Fuel injection state detection device for a fuel injection system, which is in an accumulator ( 12 ) stored fuel from an injection device ( 20 ), characterized by a fuel pressure sensor ( 20a . 200a ) located in a fuel passage extending from the accumulator ( 12 ) to an injection hole ( 20f ) of the injector ( 20 ) is arranged at a position which is closer to the injection hole ( 20f ) as to the accumulator ( 12 ) to detect a fuel pressure associated with the fuel injection from the injection hole (FIG. 20f ) fluctuates; a first injection quantity estimating means (S25) for estimating a fuel injection amount based on a fluctuation waveform caused in connection with the fuel injection from the detected pressure detected by the fuel pressure sensor (15); 20a . 200a ) is detected; second injection quantity estimation means (S26) for estimating the fuel injection amount based on a pressure difference between the detected pressure before the start of injection and the detected pressure after the end of the injection from the detected pressure; and injection amount calculating means (S27) for calculating the fuel injection amount based on both of the estimated results of the first and second injection amount estimating means (S25, S26). Fuel injection state detecting device according to claim 1, further comprising: a Injection rate calculating means (S24) for calculating a history waveform a fuel injection rate based on the fluctuation waveform the detected pressure; and an injection rate correction device (S28) for correcting the history waveform such that a fuel injection amount, calculated as an integration value of the gradient waveform, approaches the fuel injection amount generated by the injection amount calculating means (S27) is calculated. A fuel injection state detecting device according to claim 1 or 2, wherein the first and second injection amount estimating means (S25, S26) determine the estimation based on the detected pressure of the fuel pressure sensor (FIG. 20a . 200a ), which is detected when a fuel pumping period, while the fuel from a fuel pump ( 11 ) to the accumulator ( 12 ) is not covered with an injection period, while the fuel from the injection hole ( 20f ) is injected. A fuel injection state detecting device according to claim 1 or 2, wherein said fuel injection state detecting device is applied to a fuel injection system of a multi-cylinder internal combustion engine having a plurality of injectors (Figs. 20 ), and wherein the fuel pressure sensor ( 20a . 200a ) for each of the many injectors ( 20 ), the fuel injection state detection device further comprising: a pump fluctuation waveform obtaining means for obtaining a fluctuation waveform that is different in the detected pressure of the fuel pressure sensor ( 20a . 200a ) corresponding to a non-injection cylinder of the plurality of cylinders, in each of which injection and non-injection are sequentially carried out, and in connection with fuel pumping from a fuel pump ( 11 ) to the accumulator ( 12 ), wherein the non-injection cylinder is a cylinder in which fuel injection is not currently performed, wherein the first and second injection amount estimating means (S25, S26), when the fuel pumping period coincides with the fuel injection period, the fuel injection amount in estimating an injection cylinder based on a fluctuation waveform obtained by dividing a component of the fluctuation waveform, which is detected by the pump fluctuation waveform obtaining means, from the fluctuation waveform of the fuel pressure sensor (FIG. 20a . 200a ), which corresponds to the injection cylinder, is subtracted, the injection cylinder being a cylinder in which fuel injection is currently being performed. The fuel injection state detecting device according to any one of claims 1 to 4, wherein the second injection amount estimating means (S26) detects the detected pressure of the fuel pressure sensor (S26). 20a . 200a ) detected when an injection start is commanded by an injection command signal commanding the injection of the fuel is used as the detected pressure obtained before the start of the injection. The fuel injection state detecting device according to any one of claims 1 to 5, wherein the second injection amount estimating means (S26) detects the detected pressure of the fuel pressure sensor (S26). 20a . 200a ) detected when an injection start is commanded by an injection command signal of a next injection is used as the detected pressure resulting after the end of the injection. A fuel injection state detection device according to any one of claims 1 to 4, wherein the fuel injection state detection device is applied to a fuel injection system which is capable of carrying out a multi-stage injection in which the fuel is injected several times from the same injector ( 20 ) is injected per combustion cycle, wherein the first injection amount estimation means (S25) estimates a fuel injection amount of each injection stage of the multi-stage injection based on a pressure fluctuation waveform fluctuating with each injection, and the second injection quantity estimation means (S26) calculates a fuel injection amount per combustion cycle based on a pressure difference between estimates detected pressure before the injection start of the first injection stage in the multi-stage injection and the detected pressure after the end of injection of the last injection stage in the multi-stage injection, the fuel injection condition detection apparatus further comprising: a main injection amount estimating means (S26) for estimating an injection amount of a main injection, the injection quantity of which is the largest of the injection quantity estimated by the first injection amount estimating means (S25) in the multi-stage injection by subtracting a total amount of the injection quantity or injection amounts of the other injection or the other injections other than the main injection from the fuel injection amount per combustion cycle estimated by the second injection amount estimating means (S26), wherein the injection amount calculating means (S27) the main injection amount of the main injection is calculated based on the injection amount of the main injection among the injection amounts estimated by the first injection amount estimating means (S25) and the injection amount estimated by the main injection amount estimating means (S26). Fuel injection state detecting device according to claim 7, wherein the injection rate calculator (S24) a history waveform of a main injection rate of the main injection based on a pressure fluctuation waveform associated with with the main injection varies, calculated, and the injection rate correction device (S28) corrects the waveform of the main injection rate so that a main injection amount serving as an integration value of the history waveform the main injection rate is calculated, approaches the main injection quantity, calculated by the injection amount calculating means (S27) becomes. A fuel injection state detecting device according to claim 7 or 8, wherein said second injection amount estimating means (S26) detects the detected pressure of said fuel pressure sensor (S26). 20a . 200a ) detected when an injection start of the first injection stage is commanded by an injection command signal commanding the multi-stage injection of the fuel is used as the detected pressure resulting before the injection start. The fuel injection state detecting device according to any one of claims 7 to 9, wherein the second injection amount estimating means (S26) detects the detected pressure of the fuel pressure sensor (S26). 20a . 200a ) detected when an injection start of the first injection stage is commanded by an injection command signal of a next multi-stage injection is used as the detected pressure resulting after the end of injection. Fuel injection state detecting device for a fuel injection system, the fuel that is stored in a pressure accumulator ( 12 ) is stored from an injection device ( 20 ), characterized by a fuel pressure sensor ( 20a . 200a ) located in a fuel passage extending from the accumulator ( 12 ) to an injection hole ( 20f ) of the injector ( 20 ) is arranged at a position which is closer to the injection hole ( 20f ) as to the accumulator ( 12 ) is to detect the fuel pressure associated with the fuel injection from the injection hole ( 20f ) fluctuates; injection start and end of injection estimating means for estimating an injection start timing and an injection ending timing on the basis of a fluctuation waveform caused in connection with the fuel injection, from the detected pressure detected by the fuel pressure sensor (10); 20a . 200a ) is detected; injection quantity estimating means for estimating a fuel injection amount caused by said detected pressure based on a pressure difference between the detected pressure before an injection start and the detected pressure after an injection end; and injection rate calculating means for calculating a progression waveform of a fuel injection rate on the basis of the injection start timing and the injection ending timing estimated by the injection start timing and end of injection estimating means and the fuel injection amount estimated by the injection amount estimating means. A fuel injection state detecting device according to claim 11, wherein the fuel injection state detecting device is applied to a fuel injection system capable of performing a multi-stage injection in which the fuel is injected plural times from the same injector (10). 20 ) is injected per combustion cycle, wherein the time judging means for the injection start and the injection end of an injection start timing and a Estimating an injection end timing of a main injection whose injection amount is the largest in the multiple-stage injection, and wherein the injection amount estimating means determines a fuel injection amount per combustion cycle based on the pressure difference between the detected pressure before the injection start of the first injection stage in the multi-stage injection and the detected pressure after the injection end of the last injection stage in the multi-stage injection, the fuel injection state detection apparatus further comprises: non-main injection amount estimating means for estimating a fuel injection amount based on the fluctuation waveform of the detected pressure fluctuating with each injection for each injection stage other than the main injection; and a main injection amount estimating means for estimating an injection amount of the main injection by subtracting a total amount of the injection amount or injection quantities of the injection estimated by the non-main injection amount estimating means from the fuel injection amount per combustion cycle estimated by the injection amount estimating means, wherein the injection rate calculating means has a The history waveform of a fuel injection rate of the main injection is calculated on the basis of the injection start timing and the injection end timing estimated by the injection start timing and injection end timing means and the main injection amount estimated by the main injection amount estimating means. A fuel injection state detecting device according to any one of claims 1 to 12, wherein the fuel pressure sensor ( 20a . 200a ) on the injection device ( 20 ) is attached. A fuel injection state detecting device according to claim 13, wherein said fuel pressure sensor ( 20a . 200a ) at a fuel inlet ( 22 ) of the injector ( 20 ) is attached. A fuel injection state detecting device according to claim 13, wherein said fuel pressure sensor ( 20a . 200a ) inside the injector ( 20 ) is mounted to the fuel pressure in an internal fuel channel ( 25 ) extending from a fuel inlet ( 22 ) to the injection hole ( 20f ) of the injector ( 20 ). A fuel injection state detecting device according to any one of claims 1 to 15, wherein a diaphragm ( 12a ) in a fuel passage extending from the accumulator ( 12 ) to a fuel inlet ( 22 ) of the injector ( 20 ) is arranged to the pressure pulsation of the fuel in the pressure accumulator ( 12 ), and the fuel pressure sensor ( 20a . 200a ) downstream of the diaphragm ( 12a ) with respect to a fuel flow direction.