CN103244296A

CN103244296A - Fuel pressure waveform acquiring equipment for fuel injection system

Info

Publication number: CN103244296A
Application number: CN2013100283383A
Authority: CN
Inventors: 野野山由晴; 山田直幸
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2012-02-10
Filing date: 2013-01-24
Publication date: 2013-08-14
Anticipated expiration: 2033-01-24
Also published as: CN103244296B; JP2013163999A; DE102013101226A1; JP5635022B2; DE102013101226B4

Abstract

A fuel pressure waveform acquiring equipment comprises the following components: a pressure waveform acquiring device which is used for acquiring a first pressure waveform detected through a fuel pressure sensor as a multi-segment injection pressure waveform that occurs in performing multi-segment fuel injection; a model waveform storing device which is used for storing a standard model waveform as a second pressure waveform, wherein the second pressure waveform occurs when target injection which is earlier than a second segment or a later period in the multi-period ejection is performed imaginarily; a waveform extracting device which is used for subtrating the model waveform from the multi-segment injection pressure waveform for extracting a third pressure waveform that is caused by the target injection; and a compensating device which is used for compensating the model waveform through damping the model waveform for a certain damping value, wherein the damping value depends on injection interval between the earlier injection and the target injection.

Description

The fuel pressure waveform that is used for fuel injection system obtains equipment

Technical field

The present invention relates to a kind of be used to obtaining the equipment that the fuel pressure time variation that causes by the injects fuel from internal-combustion engine is used as pressure waveform.

Background technique

For accurately output torque and the emissions status of controlling combustion engine, must the control spray regime, this spray regime comprises emitted dose and the time for spraying of the fuel that ejects from the spray-hole of Fuelinjection nozzle.Publication number is 2010-3004(patent documentation 1) and 2009-57924(patent documentation 2) Japanese patent application described, the time of using fuel pressure sensor to detect fuel pressure in the fuel feed passage of leading to fuel orifice that is caused by the injection of fuel changes to detect the technology of actual fuel spray regime thus.

For example, actual fuel injection beginning can be detected constantly by detecting the moment that fuel pressure begins to descend, and actual fuel injection amount can be detected by detecting the decrease that sprays the fuel pressure that causes by fuel.The fuel spray regime that detects reality makes can accurately control the fuel spray regime.

By way of parenthesis, when execution multistage fuel sprays, must consider ensuing problem, in this multistage fuel sprays, repeatedly carry out the fuel injection in the burning cycle.(b) part among Fig. 5 shows when execution multistage fuel sprays by detected two pressure waveforms of fuel pressure sensor.In these pressure waveforms, the pressure waveform W that is surrounded by dot and dash line is corresponding to the injection in n stage.This pressure waveform W with corresponding to before injection, i.e. m(=n-1) repercussions (fluctuation composition) overlaid of other pressure waveforms of the injection in stage, these repercussions are the parts of being surrounded by the dot and dash line in the part of Fig. 5 (d).

In the technology that patent documentation 1 is described, to carry out separately shown in its part at Fig. 5 of model waveform CALn-1((d) that the m stage occurs spray the time) (only just not using under the situation that the n stage sprays owing to the waveform of m stage due to spraying) be stored in the mathematical formulae, pressure waveform W deducted only spray the pressure waveform Wn that causes by the n stage shown in the part (f) that model waveform CALn-1 is extracted in Fig. 5, and determine actual spray regime based on the pressure waveform Wn that extracts.

Yet the present inventor has been found that through various tests: by deduct model waveform CALn-1 simply from the pressure waveform W that detection obtains, only can not accurately obtain and spray the pressure waveform Wn that (target injection) causes by the n stage.

Summary of the invention

A kind of fuel pressure waveform for fuel injection system that the invention provides of describing in the claim 1 obtains equipment, this fuel injection system comprises injection valve and fuel pressure sensor, this injection valve is used for fuel is ejected into internal-combustion engine from its spray-hole, this fuel pressure sensor changes for detection of the time owing to fuel fuel pressure from the fuel feed passage of leading to spray-hole that the injection of spray-hole causes and is used as pressure waveform

This equipment comprises:

The pressure waveform obtaining device, it is used for obtaining by detected first pressure waveform of fuel pressure sensor, as carrying out the multistage jet pressure waveform that occurs when multistage fuel sprays, in this multistage fuel injection, at each burning cycle multi-injection fuel of internal-combustion engine;

Model waveform storage device, it is used for storage as the model waveform of the standard of second pressure waveform, this second pressure waveform is assumed in to have carried out to spray compared with target and is in the more early-injection of earlier stage and does not carry out and occur when target is sprayed, and it is in spraying the multistage second or the injection in more late stage that this target is sprayed;

The waveform extracting device, it is used for deducting the model waveform from multistage jet pressure waveform and extracts the 3rd pressure waveform that is caused by the target injection; And

Compensation device, it is used for compensating being used for carrying out the model waveform that subtracts each other by model waveform attenuating one dough softening is come, and this dough softening depends on the injection interval that sprays to target from early-injection more.

The present inventor has carried out test 1 and test 2, in order to the accuracy of checking by the pressure waveform Wn that deducts model waveform CALn-1 the waveform W that sprays time detection from the multistage and extract.

In test 1, the waveform that detection occurs when spraying in the execution multistage is used as waveform W(referring to the part (b) of Figure 11).Next, only carry out the n stage of multistage in spraying and sprays, and obtain the waveform that this moment, detection obtained and be used as waveform W0n(referring to the part (c) of Figure 11).Next, from waveform W, deduct waveform W0n, with the waveform W0n-1 shown in the part (d) of obtaining Figure 11.

At first, the inventor thinks that the waveform W0n-1 that obtains thus represents to be assumed to be at and only carries out the waveform that (n-1) stage of multistage in spraying spray appearance when spraying as single phase.But find that subsequently waveform W0n-1 is assumed in the model waveform CALn-1 that only carries out the waveform that the multistage occurs when (n-1) stage in spraying sprays and inequality with expression in the following areas: the pulse amplitude A1 of that part of waveform W0n-1 of appearance is less than the pulse amplitude A2 of model waveform CALn-1 n stage injection beginning after.

The inventor infers that the reason that such phenomenon occurs is as follows.Fuel pressure pulsation (pressure wave) is propagated towards spray-hole, then, and the pulse injected bore portion reflection and propagate towards fuel pressure sensor of a part of fuel pressure.Correspondingly, because the influence of the fuel pressure that partly reflects from spray-hole pulsation, detect at the fuel pressure sensor place and to have occurred fluctuation waveform (along the part (c) of Fig. 6 or the asymptote k1 (d) or the waveform of k2) in the fuel pressure waveform that obtains.Spray to prevent fuel although closed spray-hole, because this part of fuel pressure pulsation of injected bore portion reflection is bigger, so that pulse amplitude just becomes is big.

On the other hand, opening spray-hole with when carrying out the fuel injection, owing to the fuel pressure pulsating energy gets at outside the spray-hole, so the part of injected bore portion reflection is just very little.Correspondingly, when carrying out fuel and spraying, the pulsation that comprises in the fuel pressure waveform (fluctuation waveform) is little when not carrying out fuel and spray.The amount of that part in the fuel pressure waveform outside the spray-hole changes according to be ejected into the injection interval that the n stage sprays from (n-1) stage, correspondingly, pulse amplitude reduce the influence that degree (dough softening) is subjected to the amount of this part.

According to the invention described in the claim of making based on test 1 result and inventor's deduction 1, in example shown in Figure 5, to detect in order spraying from the multistage and to deduct the model waveform CALn-1 that sprays corresponding to (n-1) stage the waveform W that obtains and extract pressure waveform Wn, come model waveform CALn-1 is compensated by the dough softening that decays, this dough softening depends on from (n-1) stage and is ejected into the injection interval that the n stage sprays.

This can make model waveform CALn-1 more deduct the n stage the waveform W that obtains and detect the actual waveform W0n-1 that the waveform W0n that obtains obtains during single the injection close to detecting when spraying from the multistage, correspondingly, detect in the time of can spraying from the multistage accurately to extract the waveform W obtain by the n stage and spray the pressure waveform Wn that (target injection) causes.

More accurately, the degree that reduces of pulse amplitude changes according to the pressure of the pulsation of the fuel pressure outside spray-hole is big or small.That is to say that the intermediate value that departs from change pressure along with the pressure of pulsing from the fuel pressure of spray-hole emission is more many, the degree that reduces of pulse amplitude just becomes more big.

According to the present invention described in the claim 2, compensation device pressure size at the model waveform at spray-hole place when opening spray-hole and spray to carry out target changes the dough softening.

This feasible dough softening that can suitably change the model waveform according to the pressure size of the pulsation of the fuel pressure outside spray-hole.

According to the present invention described in the claim 3, compensation device is according to depending on that the pressure transformation period section of the model waveform of injection interval changes the dough softening.

Pressure wave in the fuel feed passage is reflected by the part that narrows down in the passage or seal, and as a result of, the fuel pressure waveform becomes the waveform that periodically increases repeatedly and reduce, and that is to say, becomes the fluctuation waveform.Correspondingly, the pressure size that propagates into the fuel pressure pulsation of spray-hole when spray-hole is opened is ejected into injection interval that target sprays and cyclically-varying with regard to depending on from earlier stage.

Structure according to described in the claim 3 can depend on the dough softening that changes the model waveform according to the model waveform pressure transformation period section of injection interval.This makes the pressure transformation period section that can depend on the fuel pressure pulsation that propagates into spray-hole when spray-hole is opened suitably change the dough softening of model waveform.

In addition, find that by test 2 the discharge time section Tqn that sprays along with the n stage becomes more long subsequently, the pulse amplitude A1 of waveform W0n-1 just becomes more little.That is to say that along with the valve cycle of opening becomes more long, the volume reflection of fuel pressure pulsation just becomes more little, correspondingly, it is more little that pulse amplitude just becomes.

In test 2, measured detected pulse amplitude A1 in the ratio A 1/A2(test 1 than the ratio of pulse amplitude A2) variation of the discharge time section of how spraying along with the n stage changes.Solid line among Figure 12 shows the measurement result when the fuel pressure that is supplied to fuel orifice is set at 200MPa, 140MPa, 80MPa and 40MPa respectively.

Figure 12 shows, no matter the pressure of supplied fuel how, the discharge time section Tqn that sprays Tqn along with the n stage becomes more long, and the pulse amplitude A1 of detected waveform W0n-1 becomes more little.By way of parenthesis, when not carrying out the n stage when spraying (when discharge time section Tqn is zero), ratio A 1/A2 is 1.This means, carry out the n stage and spray and influenced detected waveform W0n-1, thereby make that pulse amplitude A1 is littler.

According to the present invention described in the claim 7, compensation device compensates be used to the model waveform that subtracts each other the model waveform by becoming more long along with the discharge time section more muchly.

More particularly, according to the present invention described in the claim of making based on test 1 and test 2 result and inventor's deduction 7, in example shown in Figure 5, extract pressure waveform Wn in order to deduct the model waveform CALn-1 that sprays corresponding to (n-1) stage the detected waveform W when spraying from the multistage, become more long and decay more muchly and come compensation model waveform CALn-1 by the discharge time section of spraying along with the n stage.

According to the present invention described in the claim 7, because the actual waveform W0n-1 that model waveform CALn-1 is further approached deduct the detected waveform W when spraying from the multistage n stage detected waveform W0n obtains during injection separately, therefore, extract exactly the detected waveform W in the time of can spraying from the multistage by the n stage and spray the pressure waveform Wn that (target injection) causes.

Description of drawings

In the accompanying drawings:

Fig. 1 schematically shows the figure of structure that the fuel pressure waveform that comprises according to the embodiment of the invention obtains the fuel injection system of equipment;

Fig. 2 shows the flow chart of the step of the fuel injection control process of being carried out by fuel injection system;

Fig. 3 shows the flow chart that is obtained the step of the fuel spray regime testing process that equipment carries out by the fuel pressure waveform;

The time diagram of the relation when Fig. 4 shows detected pressure waveform and single phase fuel injection when single phase, fuel sprayed between the transition waveforms of Spraying rate;

Fig. 5 is the time diagram of having explained fluctuation removal operation included in the fuel pressure testing process shown in Figure 3;

Fig. 6 is the time diagram of having explained fluctuation removal operation included in the fuel pressure testing process shown in Figure 3;

Fig. 7 shows the time diagram of the relation between the dough softening of pulse amplitude in fuel injection interval and the detected pressure waveform;

Fig. 8 shows the flow chart that the step of operation is removed in fluctuation;

Fig. 9 shows the plotted curve of the relation between the offset c of damping coefficient k of injection interval and model waveform;

Figure 10 shows the time diagram of the relation between the specific part of elapsed time and model waveform;

Figure 11 shows the result's of the test of being carried out by the present inventor 1 plotted curve; And

Figure 12 shows the result's of the test of being carried out by the present inventor 2 plotted curve.

Embodiment

Fig. 1 schematically shows the structure for the fuel injection system of on-vehicle internal combustion engine, and this system comprises that the fuel pressure waveform according to the embodiment of the invention obtains equipment.In this embodiment, internal-combustion engine is to have cylinder #1 to the diesel engine of cylinder #4 for what the execution compression autoignition burnt.Fuel injection system operates fuel under high pressure to be ejected into cylinder #1 in cylinder #4.

In Fig. 1, reference character 10 representative is installed in the Fuelinjection nozzle of each cylinder #1 to the #4, and 20 representatives are installed in the fuel pressure sensor on the

Fuelinjection nozzle

10, and 30 representatives are installed in the ECU(electronic control unit on the vehicle) 30.Implement the fuel pressure waveform by ECU30 and obtain equipment.Fuel injection system operates, and makes the fuel be stored in the fuel tank 40 be fed to common rail 42 as accumulator by high-pressure service pump 41, and is assigned to the Fuelinjection nozzle 10 of each cylinder via high-voltage tube 43.

Fuelinjection nozzle 10 comprises main body 11, pin 12 and as the o 13 of actuator.Main body 11 portion within it is formed with high-pressure channel 11a.Be fed to the fuel process high-pressure channel 11a of Fuelinjection nozzle 10 with injected from spray-hole 11b from being total to rail 42.Part of fuel in the high-pressure channel 11a flows among the main body 11 inner back pressure chamber 11c that form.Open and close the Leak hole 11d of back pressure chamber 11c by control valve 14.Open and close control valve 14 by o 13.Pin 12 is applied in the fuel pressure along the valve closing direction of elastic force and the back pressure chamber 11c of spring 15, and be applied in the inner fuel receiver 11f that forms of high-pressure channel 11a open the fuel pressure of direction along valve.

Fuel pressure sensor 20 is arranged in the fuel feed lines between common rail 42 and the spray-hole 11b (for example, in high-voltage tube 43 or high-pressure channel 11a), in order to detect fuel pressure.In this embodiment, fuel pressure sensor 20 is installed on the attachment portion between high-voltage tube 43 and the main body 11.Alternately, fuel pressure sensor 20 also can be installed on the main body 11 as shown by the dot and dash line among Fig. 1.Cylinder #1 is provided with fuel pressure sensor 20 to each Fuelinjection nozzle 10 of #4.

Next, explain the running of the Fuelinjection nozzle 10 with said structure.When o 13 was de-energized, the elastic force of spring 16 was closed control valve 14.In this state, because the fuel pressure of back pressure chamber 11c is higher, so pin 12 is closed, eject from spray-hole 11b to prevent fuel.On the other hand, when o 13 was energized, control valve 14 resisted the elastic force of springs 16 and opens.In this state and since back pressure chamber 11c in fuel pressure lower, so pin 12 be opened so that fuel ejects from spray-hole 11b.

When carrying out the fuel injection by o 13 is switched on, the fuel that flows to the back pressure chamber 11c from high-pressure channel 11a is released to low-pressure channel 11e by Leak hole 11d.That is to say that when carrying out the fuel injection, the fuel in the high-pressure channel 11a always leaks among the low-pressure channel 11e by back pressure chamber 11c.

ECU30 controls spray regime to the energising of o 13 with the opening and closing of controlling pin 12 thus by control.More particularly, ECU30 is based on the rotating speed of engine output shaft, engine loading etc., calculate the target jet mode that comprises the injection beginning moment, the finish time of injection and fuel injection amount, and control realizes the target jet mode that calculates to the energising of o 13.

Next, with reference to the flow chart of figure 2, explain by ECU30 carry out be used for control to the energising of o 13 to control the process of fuel spray regime thus.

This process begins at step S11, and in step S11, reading displayed goes out the predefined parameter of engine operating status, and this parameter comprises engine speed, engine loading and the pressure that is fed to the fuel of Fuelinjection nozzle 10.

At step S12 subsequently, set the optimum target jet mode based on the parameter that reads among the step S11.Can be by coming the target setting pattern with reference to spraying control graph, best various jet modes for the various combinations of parameter value have prestored in spraying the control mapping graph.By demonstrating the parameter objective definition jet mode of injection phase number (number of times of the fuel injection that each burning cycle will be carried out), the injection beginning moment, discharge time section (fuel injection amount) etc.That is to say that the injection control graph has demonstrated the relation between these parameters and the best jet mode.

At step S13 subsequently, will output to the o 13 of Fuelinjection nozzle 10 according to the injection command signal of the target jet mode of in step S12, setting.As a result of, carry out fuel injection control, make jet mode become for best jet mode the present engine operating condition shown in the parameter that in step S11, reads.

But, because the individual difference between ageing deterioration or the Fuelinjection nozzle 10, the actual jet mode jet mode that might depart from objectives.Correspondingly, compensate spraying command signal, so that actual jet mode (actual spray regime) is consistent with the target jet mode.As described later, can detect actual jet mode based on the output value of fuel pressure sensor 20.In addition, in this embodiment, executed signal compensation is learnt, and used learning value to calculate the injection command signal next time.

Next, with reference to the flow chart of figure 3, explain the process that is used for detecting based on the output value of fuel pressure sensor 20 (calculating) actual ejection state.

Carry out this process in the crankangle that each predetermined calculation cycle or each are predetermined by the microcomputer of ECU30.This process begins at step S21, in step S21, reads the output value of the detected fuel pressure of expression from be installed in the fuel pressure sensor 20 of cylinder #1 to the #4.Preferably, detected fuel pressure is subjected to filtering.

Come read operation among the interpretation procedure S21 at length, the time diagram of Fig. 4 to show that each is worth time dependent example during spray-hole 11b is opened and closed once time period with reference to the time diagram of figure 4.

The part of Fig. 4 (a) shows the injection command signal that outputs to Fuelinjection nozzle 10 in step S13 shown in Figure 3.The pulse enable (pulse-on) that sprays in the command signal is switched on to o 13, makes spray-hole 11b open.That is to say, in the pulse enable beginning of Is command injection constantly, in the end-of-pulsing end of Ie command injection constantly.Correspondingly, can open period T q by the valve of controlling spray-hole 11b according to the pulse enable cycle of spraying command signal, thus control emitted dose Q.The part of Fig. 4 (b) shows by the time variation (transformation) of spraying the fuel injection rate of ordering the spray-hole 11b that causes.The time that the part of Fig. 4 (c) shows the output value (detected fuel pressure) of the fuel pressure sensor 20 that is caused by the transformation of fuel injection rate changes.

ECU30 carries out the subroutine procedure different with the process shown in Fig. 3, in order to obtain the output value of fuel pressure sensor 20 with the time lag shorter than process shown in Figure 3, so that can track the track of the fuel pressure transition waveforms shown in the part (c) of Fig. 3.In this embodiment, read the output signal of fuel sensor 20 with the time lag shorter than 50 μ s (being preferably 20 μ s), and in step S21, one after the other gather the output value of obtaining thus.

Between the time of using fuel pressure sensor 20 detected pressure waveforms and fuel injection rate changes, there is coherence described below.Correspondingly, can estimate the transient waveform of Spraying rate according to detected fuel pressure waveform.

In the example of the time of the fuel injection rate shown in the part (b) of Fig. 4 variation, o 13 begins to be energized at moment Is, and fuel begins to be ejected from spray-hole 11b thereafter, and as a result of, fuel injection rate begins at change point R3 place to increase.That is to say, begun actual fuel and sprayed.Thereafter, Spraying rate reaches its maximum value at change point R4 place, stops to increase at change point R4 place Spraying rate.This is because needle-valve 20c begins to promote at change point R3, and the amount that promotes at change point R4 place reaches its maximum value.

In this article, term " change point " is defined as follows.Calculate the second-order differential value of Spraying rate (perhaps by fuel pressure sensor 20 detected fuel pressures).The second-order differential value that calculates is reached the point of extreme value, and namely the flex point of the waveform of second-order differential value is defined as the change point of Spraying rate (or detected fuel pressure).

After the moment, Te was de-energized, Spraying rate began to reduce at change point R7 at o 13.Thereafter, the change point R8 place vanishing of Spraying rate when the injection of reality finishes.This is because needle-valve 28 begins to fall at change point R7 place, and is fully closed at the spray-hole 11b of change point R8 place.

In the example that is changed by time of fuel pressure sensor 20 detected fuel pressures shown in the part (c) of Fig. 4, the fuel pressure before the change point P1 equals the fuel supply pressure of P0.Owing to being provided, driving current answers o 13, the change point P1 place after the moment Is that fuel injection command is output and before the change point R3 that Spraying rate begins to increase, and fuel pressure begins to reduce.This is that as a result of, the pressure of back pressure chamber 11c reduces because control valve 14 is opened Leak hole 11d at change point P1 place.Thereafter, the fuel pressure that begins at change point P1 reduce temporarily stopped at change point P2.This is because Leak hole 11d is opened fully, as a result of, depends on that the leak-down rate of diameter of the opened areas of Leak hole 11d becomes constant.

Subsequently, because Spraying rate begins increase at change point R3, so detected fuel pressure begins to reduce at change point P3.Thereafter, Spraying rate reaches its maximum value at change point R4, and as a result of, the reducing of detected fuel pressure stopped at change point P4.Decrease during the decrease during the time period from change point P3 to change point P4 is greater than the time period from change point P1 to change point P2.

Subsequently, detected fuel pressure begins to increase at change point P5.This is because control valve 14 has been closed Leak hole 11d, and as a result of, the pressure of back pressure chamber 11c increases.Thereafter, the increase of the detected fuel pressure that begins at change point P5 has temporarily stopped at change point P6.

Subsequently, owing to Spraying rate begins to reduce at change point R7, so detected fuel pressure begins to increase at change point P7.Thereafter, Spraying rate reaches its maximum value at change point R8, the result be detected fuel pressure reduce stopped at change point P8.The decrease of decrease during time period from change point P7 to change point P8 during greater than the time period from change point P5 to change point P6.Detected fuel pressure reduced repeatedly with constant cycle of T10 and the mode that increases decays.

Above-mentioned change point P3, P4, P7 and P8 detected make and can estimate: Spraying rate increases the time that elapsed time R3(actual ejection begins), the maximum injection reach time R4, Spraying rate and reduce the fuel that elapsed time R7 and Spraying rate reduce concluding time R8(reality and spray the time that finishes).In addition, can be based on the following relation of explaining between the variation of the variation of Spraying rate and detected fuel pressure, change to estimate that the time of Spraying rate changes according to time of detected fuel pressure.

The pressure reduction ratio P α during the time period from change point P3 to change point P4 and the Spraying rate Magnification R α during the time period from change point R3 to change point R4, there is coherence.The pressure Magnification P γ during the time period from change point P7 to change point P8 and the Spraying rate reduction rate R γ during the time period from change point R7 to change point R8, there is coherence.Between pressure decrease P β (pressure maximum decrease) and Spraying rate increase R β (maximum injection rate), there is coherence.Correspondingly, detected pressures reduction rate P α, pressure Magnification P γ and pressure maximum decrease P β can changing by the time from fuel sensor 20 detected fuel pressures estimate Spraying rate Magnification R α, Spraying rate reduction rate R γ and maximum injection rate R β.As mentioned above, owing to can estimate various state R3, R4, R7, R8, R α, R β, the R γ of Spraying rate, the time of the fuel injection rate shown in therefore can the part (b) of drawing for estimate 4 changes (transition waveforms).

The integral value (shown in the S of shadow region) of the Spraying rate between the beginning of actual ejection and the end is corresponding to emitted dose Q.Have coherence between the integral value of the integral value S of Spraying rate and the transition waveforms of detected fuel pressure, this be because the part of the transition waveforms of detected fuel pressure corresponding to the actual ejection time period (part between change point P3 and the change point P8) from start to end.Correspondingly, calculate the pressure integral value can changing by the time from fuel sensor 20 detected fuel pressures, estimate the Spraying rate integral value S corresponding to emitted dose Q.Therefore we can say that fuel pressure sensor 20 has played the effect of spray regime sensor, fuel pressure sensor 20 detects the pressure of the fuel that is supplied to Fuelinjection nozzle 10, as the physical quantity relevant with spray regime.

Turn back to Fig. 3, in step S21 step S22 subsequently, determine that whether the current injection that is just detecting is that second stage in spraying the multistage is sprayed or subsequent stage sprays.If the definite result among the step S22 is sure, then this process proceeds to step S23, in step S23, the waveform that obtains among the step S21 is carried out fluctuation remove operation.Explain this fluctuation removal operation below with reference to Fig. 5.

Part among Fig. 5 (a) shows when having exported the injection command signal of the injection of command execution multistage (being to spray in two stages in this embodiment), is sent to the time diagram of the driving current of o 13.Part among Fig. 5 (b) shows the figure of the waveform W of detected fuel pressure when the injection command signal of having exported shown in the part (a).Part among Fig. 5 (c) shows, and when having exported the injection command signal of command execution single phase injection, is sent to the time diagram of the driving current of o 13.Part among Fig. 5 (d) shows the waveform of detected fuel pressure when the injection command signal of having exported shown in the part (c).

Last stage sprays that ((n-1) stage sprays, (n-2) stage sprays, (n-3) stage sprays to waveform W with it in its part of spraying corresponding to the n stage (part of being surrounded by the dot and dash line of part in (b)) ...) the repercussions overlaid.The repercussions that spray with (n-1) stage shown in the part among Fig. 5 (d) are as example, at (n-1) stage AEI After End of Injection, increase repeatedly and reduce and the fluctuation waveform of decaying (by the waveform that dot and dash line was surrounded in the part (d)) shows as repercussions with some cycles (being T10 in this example).That part of waveform that sprays corresponding to the n stage among these repercussions (fluctuation waveform) and the waveform W (part of being surrounded by the dot and dash line in partly (b)) overlaid.Correspondingly, if go out the time variation (transition waveforms shown in the part of Fig. 4 (b)) of being sprayed the Spraying rate that causes by the n stage based on detected waveform W direct estimation, then evaluated error can become very big.

Therefore, in step S23, carry out fluctuation and remove operation, in step S23, deduct among the waveform W that causes at the repercussions (fluctuation waveform) of stage injection early from detected the injection by the n stage, spray the pressure waveform Wn(that causes referring to the part (f) of Fig. 5 to extract by the n stage).

More particularly, obtain and store the test result of various patterns in the single phase injection in advance as various fluctuation waveforms.These various patterns are included in the fuel pressure (fuel pressure when the fuel injection beginning of injection beginning; P0 shown in Fig. 4 or P2) aspect single phase of differing from one another sprays, perhaps sprays opening the single phase that differs from one another aspect the emitted dose of time period Tq corresponding to valve.To be stored in the storage that is included among the ECU30 as the model waveform by the fluctuation waveform that the form of test acquisition and employing mathematic(al) representation is represented.

In this embodiment, with the form memory model waveform of following formula (1), wherein, p is the value (normal value of the fuel pressure that is detected by fuel pressure sensor 20) of model waveform.In formula (1), parameter A, k, ω and θ are respectively amplitude, damping coefficient, frequency and the phase place of damped vibration.Alphabetical t in the formula (1) represents elapsed time.Obtain the normal value p of detected fuel pressure by the formula (1) as the function of the variable of elapsed time t.For different jet modes each among setup parameter A, k, ω and the θ differently.

P=Aexp(-kt)sin(ωt+θ)……(1)

For example, model waveform for the standard of the repercussions (fluctuation waveform) that obtain spraying as (n-1) stage, select the immediate model waveform of jet mode of jet mode and (n-1) stage injection in the various model waveforms of from storage, storing, and this model waveform that is selected is set to the model waveform CALn-1 of the standard of the repercussions (fluctuation waveform) that spray as (n-1) stage.Dotted line in the part of Fig. 5 (e) is represented model waveform CALn-1, and the solid line in the part of Fig. 5 (e) is represented detected waveform W.By from detected waveform W, deducting model waveform CALn-1, extract the pressure waveform Wn shown in the part (f) of Fig. 5.The pressure waveform Wn that extracts does not thus comprise the early fluctuation waveform element of the injection in stage, correspondingly, pressure waveform Wn with is sprayed the Spraying rate that causes by the n stage and changes and have coherence highly.

In the part (e) and the example shown in the part (f) of Fig. 5, from detected waveform W, only deducted the model waveform CALn-1 of the fluctuation waveform of expression (n-1) stage injection.But, can also from detected waveform W, deduct the fluctuation waveform that (n-2) stage sprays and earlier stage is sprayed.In example shown in Figure 6, from detected waveform W, deducted the fluctuation waveform (model waveform CALn-1 and model waveform CALn-2) that (n-1) stage sprays and (n-2) stage sprays.

The present inventor has been found that the reduction rate of the pulse amplitude A1 of detected waveform W0n-1 depends on m(=(n-1)) stage spray and the n stage between spraying injection interval Tmn and change.

Fig. 7 shows the figure of the example of the relation between injection interval Tmn and the reduction rate.As shown in Figure 7, the detection waveform W0n-1 that sprays of (n-1) stage comprises and sprays the fuel pressure that causes by (n-1) stage and change Cn-1, and the detection waveform W0n that sprays of n stage comprises by the n stage and sprays the fuel pressure variation Cn that causes.In example shown in Figure 7, partly (a), the situation when partly (b) and part (c) show injection interval respectively and be Tmn1, Tmn2 and Tmn3, wherein Tmn1〉Tmn2〉Tmn3.

In the example shown in part (a) and the part (c), detection waveform W0n-1 sprays the fuel pressure variation Cn overlaid that causes at its trough and by the n stage.Correspondingly, because the pressure of the pressure wave outside the spray-hole 11b becomes minimum herein, so the amplitude fading degree of detection waveform W0n-1 is greater than by the amplitude fading degree of compensation model waveform CALn-1 before.On the other hand, in the example shown in the part (b) of Fig. 7, detection waveform W0n-1 sprays the fuel pressure variation Cn overlaid that causes at its node and by the n stage.Correspondingly, because the pressure of the pressure wave outside the spray-hole 11b is in the centre (value at the flex point place) of change pressure, so the amplitude fading degree of detection waveform W0n-1 is less than by the amplitude fading degree of compensation model waveform CALn-1 before.

As mentioned above, in this embodiment, model waveform CALn-1 and the CALn-2 that selects is compensated for as the waveform that has been attenuated a dough softening, this dough softening depends on from the m stage and is ejected into the injection interval Tmn that the n stage sprays." dough softening " is corresponding to the damping coefficient k in the formula (1).

In the part (c) and the example shown in the part (d) of Fig. 6, model waveform CALn-1 and CALn-2 are compensated so that the bigger waveform of their dough softening.In each of the part (c) of Fig. 6 and part (d), before dotted line k1 and dot and dash line k2 represent respectively to compensate along the asymptote of the crest of model waveform, and after the compensation along the asymptote of the crest of model waveform.When the damping coefficient k in the change formula (1), asymptotic slope also is changed.That is to say that when increasing damping coefficient k with the increase dough softening, asymptote k1 is changed to asymptote k2, wherein, the slope of asymptote k2 is greater than k1.

Turn back to Fig. 3, in step S23 step S24 subsequently, whether the definite result in step S22 regularly (if the current injection that is just detecting be confirmed as be to spray the phase I), just by detected force value (pressure waveform) being differentiated to obtain the waveform of pressure differential value, when the definite result among the step S22 when being sure (if the current injection that is just detecting be confirmed as be that second stage is sprayed or later injection), just by to detected be subjected to fluctuating remove the waveform that the force value (pressure waveform) of operating differentiates to obtain the pressure differential value.

At step S25 to step S28 in, use the differential pressure value that in step S24 obtain come the various spray regimes part (b) of calculating chart 4 shown in thereafter.More particularly, in step S25, calculate injection beginning time R3, in step S26, calculate and spray concluding time R8, in step S27, calculate maximum spout and penetrate and reach time R4 and Spraying rate reduces elapsed time R7, and in step S28, calculate maximum injection rate R β.Incidentally, when emitted dose hour, the maximum injection reaches time R4 to reduce elapsed time R7 with Spraying rate is consistent each other.

In step S29 subsequently, calculate the integral value (shadow region S) that begins the Spraying rate that finishes to actual ejection from actual ejection based on spray regime R3, the R8, R β, R4 and the R7c that calculate in the step S29 at step S25, and this integral value that this calculates is defined as actual emitted dose Q.When emitted dose was big, the shape of regional S was close to trapezoidal, and when emitted dose hour, the shape of regional S is close to triangle.Except based on spray regime R3, R8, R β, R4 and the R7, can also calculate the integral value S(emitted dose Q of Spraying rate based on the Spraying rate Magnification R α that from pressure waveform, calculates and Spraying rate reduction rate R γ).

Next, operation is removed in the fluctuation that carries out among the interpretation procedure S23 with reference to figure 8.Fig. 8 shows the step of removing operation as the fluctuation of subroutine process.This operation is from step S31, in step S31, obtains injection beginning fuel pressure P0m and emitted dose Qm that the m stage sprays.Emitted dose Qm can be the emitted dose that calculates in step S29 shown in Figure 3, perhaps can be based on to open according to the valve that sprays command signal that period T qm estimates to obtain.

In step S32 subsequently, select model waveform CALm in each model waveform of storing from storage, the jet mode of this model waveform CALm is close to by the injection beginning fuel pressure P0m that obtains among the step S31 and the defined jet mode of emitted dose Qm.In step S33 subsequently, the part of determining the current model waveform CALm that is just handling whether be assumed that among the model waveform CALm spray since the n stage compensation waiting time of finishing in the past after and the part of appearance before compensation begins.In this embodiment, the compensation waiting time is that pressure wave leaves fuel sensor 20, propagates, is total to the anastomosis part reflection between rail 42 and the high-voltage tube 43 and turn back to the 20 needed times of fuel sensor in high-voltage tube 43 and high-pressure channel 11a.If the definite result among the step S33 is sure, then operation proceeds to step S34, otherwise just proceeds to step S36.

The inventor has been found that, spray when being performed the corresponding part of pressure wave outside the spray-hole 11b at the pressure waveform of carrying out the appearance when spraying of m stage in itself and n stage and be subjected to the strongest influence that the n stage sprays, but, just do not have much influences when spraying in the n stage.This be because, flow to spray-hole 11b fuel supplement the fuel that ejects from spray-hole 11b between injection period.The inventor finds that also the influence that the n stage sprays is tended to occur after pressure wave is reflected in high-voltage tube 43 and high-pressure channel 11a.

In step S34, obtain from the m stage and spray end to the injection interval Tmn of n stage injection beginning based on being used for injection command signal that m stage and n stage spray.In step S35 subsequently, compensate based on the damping coefficient k of the model waveform CALm that selects among the step S32 of injection interval Tmn that obtains among the step S34.

Fig. 9 shows for the offset c of damping coefficient k and the relation (offset data) between the injection interval Tmn.Obtain this relation by test, and the form of this relation with performance plot is stored in the storage of ECU30.Determine offset c with reference to performance plot based on the injection interval Tmn that obtains among the step S34.Damping coefficient k in the formula (1) is compensated for as k * c, with compensation model waveform CALn-1.According to the performance plot shown in Fig. 9, the pressure transformation period section according to the model waveform CALn-1 of injection interval Tmn is depended in the variation of offset c.That is to say, the variation of the dough softening based on when opening spray-hole 11b and spray to carry out the n stage in the pressure size of the model waveform CALn-1 at spray-hole 11b place.

When the model waveform CALn-2 that deducts (n-2) stage from detected waveform W sprays the pressure waveform Wn that causes to extract by the n stage, with reference to the performance plot shown in the figure 9, based on being ejected into injection interval Tmn that the n stage sprays from (n-1) stage and being ejected into the corrected value c of damping coefficient k that injection interval Tmn that the n stage sprays is identified for the model waveform CALn-2 of (n-2) from (n-2) stage, in order to compensate the waveform CALn-2 of (n-2).

In step S36 subsequently, deduct the model waveform CALm(that in step S35, is compensated among the detection waveform W that from step S21 shown in Figure 3, obtains and in example shown in Figure 6, be CALn-1 and CALn-2).Subtract each other the waveform that obtains corresponding to spraying the pressure waveform Wn that causes by the n stage shown in the part (e) shown in the part (f) of Fig. 5 or Fig. 6 by this.

Above-described embodiment provides following advantage.

The variation of the reduction rate of the pulse amplitude A1 of the waveform W0n-1 that detection obtains is depended on from m(=(n-1)) stage is ejected into the injection interval Tmn that the n stage sprays, based on this discovery, come model waveform CALn-1 is compensated by a dough softening that model waveform CALn-1 is decayed, spray the pressure waveform Wn that (target injection) causes in order to extract by the n stage, wherein, this dough softening depends on from (n-1) stage and is ejected into the injection interval that the n stage sprays.Based on being ejected into injection interval Tmn that the n stage sprays from (n-1) stage and being ejected into the injection interval Tmn that the n stage sprays from (n-2) stage, the damping coefficient k of model waveform CALn-2 is compensated.

This feasible waveform W0n-1 that model waveform CALn-1 is more obtained near the detection shown in the part (d) of Fig. 5, this waveform W0n-1 deduct the detected waveform W when spraying from the multistage n stage when spraying separately detected waveform W0n obtain, and extract exactly the detected waveform W in the time of correspondingly, can spraying from the multistage by the n stage and spray the pressure waveform Wn that (target injection) causes.Correspondingly, according to this embodiment, owing to can detect actual spray regime R3, R8, R β, R4, R7 and Q exactly, can control to pinpoint accuracy output torque and the emissions status of motor.

The pressure size at the model waveform CALn-1 at spray-hole 11b place is depended on when opening spray-hole 11b and spray to carry out the n stage in the variation of the dough softening.Correspondingly, can suitably change the dough softening of model waveform CALn-1 according to the pressure size of the pressure wave outside the spray-hole 11b when opening spray-hole 11b and spray to carry out the n stage.

Itself the period of change according to injection interval Tmn is depended in the variation of the model waveform CALn-1 dough softening.Correspondingly, according to the pressure transformation period section of the pressure wave that when opening spray-hole 11b, propagates into spray-hole 11b, can suitably change the dough softening of model waveform CALn-1.

Only the part in model waveform CALn-1 (this part be pressure wave come and go from high-voltage tube 43 to high-pressure channel 11a one back and forth required time finish after appearance that part of), CALn-1 compensates to the model waveform.Correspondingly, can prevent from that part of model waveform CALn-1 that needn't compensate is compensated.Incidentally, can save to the compensation this restriction.

Other embodiments

Certainly, can make various modifications to above-described embodiment as described as follows.

In the above embodiments, come the entire portion of model waveform CALn-1 is compensated by the dough softening that decays of the entire portion with model waveform CALn-1, this dough softening depends on from (n-1) stage and is ejected into the injection interval Tmn that the n stage sprays.But, the also specific part of attenuation model waveform CALn-1 only, this specific part is corresponding to the pressure that occurs at spray-hole 11b place when opening spray-hole 11b and spray to carry out the n stage.Figure 10 shows the time diagram of the relation between institute's transit time and this specific part.That part of pressure waveform that the part that pressure wave takes place when spraying in the n stage as shown in Figure 10, occurs in the time of may having a strong impact on outside the spray-hole 11b and spray in (n-1) stage of execution (perhaps by shown in the dotted line by that part of model waveform CALn-1 before compensating).More particularly, detected waveform W0n-1 may be affected when spraying in (n-1) stage, makes its corresponding that part of amplitude of pressure wave outside the spray-hole 11b when spraying in the n stage reduce.According to said structure, owing to be attenuated by the specific part Tr1-Tr5 shown in the dotted line among the model waveform CALn-1, so waveform W0n-1 that model waveform CALn-1 is further arrived close to actual detected, wherein, the pressure that occurs at spray-hole 11b place when opening spray-hole 11b carrying out the n stage to spray of above-mentioned specific part Tr1-Tr5.Incidentally, such compensation can come together to carry out with the compensation of carrying out in the above embodiments.

As shown in Figure 10, interreflection owing to pressure wave thickens the corresponding specific part Tr1 of the pressure that occurs at spray-hole 11b place when opening spray-hole 11b carrying out the n stage to spray to the border of Tr5, therefore, the scope of specific part Tr increases (Tr1＜Tr2＜Tr3＜Tr4＜Tr5) in time.By increasing the scope of specific part Tr in time, the influence of pressure wave interreflection can be reflected among the model waveform CALn-1.

With reference to Figure 11, as previously described, the inventor finds that the reduction rate of the pulse amplitude A1 of detected waveform W0n-1 reduces with the increase of the discharge time section Tqn that the n stage sprays.In view of this discovery, can executable operations, this operation is used for waveform CALn-1 and the waveform CALn-2 that selects being compensated the more waveform of decaying with the increase that becomes the discharge time Tqn that sprays along with the n stage.That is to say, can compensate the damping coefficient k of selected model waveform CALm according to discharge time section Tqn.According to this structure, owing to can make model waveform CALn-1 close to the detected waveform W0n-1 shown in the part (d) of Figure 11, wherein, this waveform W0n-1 deduct the detected waveform W when spraying from the multistage n stage when spraying separately detected waveform W0n obtain, spray the pressure waveform Wn that (target injection) causes so extract the waveform W that detection obtains can spray from the multistage with high accuracy the time by the n stage.Therefore, owing to can detect actual spray regime R3, R8, R β, R4, R7 and Q with high accuracy, can control to pinpoint accuracy output torque and the emissions status of motor.

In the above embodiments, model waveform CAL by formula (1) expression is stored together with the different value of each parameter A, k, ω and the θ that are used for different jet modes (for example injection beginning fuel pressure and emitted dose), the feasible normal value p that can calculate detected pressures according to the formula (1) as the function of transit time t.But the function that normal value p itself also can be used as transit time t is stored among the figure or analog that provides for every kind of jet mode, makes these figure can be used as the model waveform.

In the above-described embodiments, Fuelinjection nozzle 10 has following structure, and wherein control valve 14 is reversible valves, and fuel always lets out from back pressure chamber 11c when pin 12 is opened.But control valve 14 also can be three-way valve, in order to prevent fuel even to let out from back pressure chamber 11c between injection period at fuel.

The top preferred embodiment of explaining is the example of the application's of describing uniquely by appended claim invention.It should be understood that and as those skilled in the art do, to make various modifications to preferred embodiment.

Claims

1. a fuel pressure waveform that is used for fuel injection system obtains equipment, described fuel injection system comprises injection valve and fuel pressure sensor, described injection valve is used for fuel is ejected into internal-combustion engine from the spray-hole of described injection valve, described fuel pressure sensor is used as pressure waveform for detection of the time variation of the fuel pressure in the fuel feed passage of leading to described spray-hole, time of described fuel pressure changes and is owing to described fuel causes that from the injection of described spray-hole described fuel pressure waveform obtains equipment and comprises:

The pressure waveform obtaining device, it is used for obtaining by detected first pressure waveform of described fuel pressure sensor, as carrying out the multistage jet pressure waveform that occurs when multistage fuel sprays, in described multistage fuel sprays, the described fuel of multi-injection during each burning cycle of described internal-combustion engine;

Model waveform storage device, it is used for the memory model waveform, described model waveform is the standard of second pressure waveform, described second pressure waveform is assumed to be at execution and sprays compared with target and be not in early that carrying out than early-injection of stage occurs when described target is sprayed, and it is that second stage in spraying the described multistage is sprayed or late phase is sprayed that described target is sprayed;

The waveform extracting device, it is used for deducting described model waveform from described multistage jet pressure waveform and sprays the 3rd pressure waveform that causes to extract by described target; And

Compensation device, it is used for by described model waveform attenuating one dough softening being compensated to carry out the described described model waveform that deducts, and the described dough softening depends on the injection interval that sprays to described target than early-injection from described.

2. fuel pressure waveform according to claim 1 obtains equipment, wherein, described compensation device be constructed to according to described spray-hole be opened to carry out described target when spraying the pressure size at the described model waveform at described spray-hole place change the described dough softening.

3. fuel pressure waveform according to claim 1 and 2 obtains equipment, and wherein, described compensation device is constructed to according to depending on that the pressure transformation period section of the described model waveform of described injection interval changes the described dough softening.

4. obtain equipment according to each the described fuel pressure waveform among the claim 1-3, wherein, described compensation device is configured to the specific part of described model waveform is decayed, and described specific part is corresponding to be opened to carry out the pressure that occurs at described spray-hole place when described target is sprayed at described spray-hole.

5. fuel pressure waveform according to claim 4 obtains equipment, and wherein, described compensation device is configured to increase as time goes by the scope of the described specific part of described model waveform.

6. obtain equipment according to each the described fuel pressure waveform among the claim 1-5, wherein, described compensation device only is configured to change the described dough softening at the part of described model waveform, finish under the situation that the described part of described model waveform is assumed that when carrying out described target and spray, pressure wave is reflected in described fuel feed passage once come and go the needed time in the past after appearance.

7. obtain equipment according to each the described fuel pressure waveform among the claim 1-6, wherein, described compensation device is configured to that the described model waveform of decaying compensates the described model waveform that deducts for described more muchly by becoming more long along with described discharge time section.