JP3525496B2 - Engine control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention predicts, by a calculation, an intake air equivalent amount at a predetermined calculation time after a predetermined calculation time, based on a detected value of the intake air equivalent amount. The present invention relates to an engine control device that controls a fuel injection amount and the like in accordance with the control.

[0002]

2. Description of the Related Art Conventionally, an engine which detects an amount corresponding to an intake air amount of an engine and controls the engine based on the detected amount, for example, controls an injection amount of a fuel injection valve in a fuel injection engine is generally known. Are known. As a general control of the fuel injection amount, the intake flow rate is detected by an air flow sensor, the intake charging efficiency is calculated based on the detected value and the engine speed, and a predetermined air-fuel ratio is obtained according to this charging efficiency. The fuel injection amount is calculated so that

By the way, in order to supply the fuel injected from the fuel injection valve to the combustion chamber during the intake stroke, it is necessary to inject the fuel to some extent before the end of the intake stroke, but at or before that injection. If only the fuel injection amount is set according to the intake air equivalent amount such as the detected charging efficiency, if the charging efficiency etc. changes between the injection of fuel and the end of the intake stroke, there will be an error in the air-fuel ratio. Occurs.

For this reason, it is possible to improve the control accuracy by predicting the intake air equivalent amount at the subsequent end of intake or the like based on the detection data of the intake air equivalent amount at the fuel injection timing or the like. Has been.

For example, in the fuel injection amount control method disclosed in Japanese Unexamined Patent Application Publication No. 1-285640, at a predetermined time before the end of the intake stroke to some extent, based on the intake pipe pressure at that time, the intake stroke end at a predetermined time ahead. By predicting the intake pipe pressure in the vicinity, calculating the fuel injection amount according to the predicted intake pipe pressure, injecting fuel, and making another prediction before the intake valve closes, the fuel supply amount The shortage amount is obtained, and the amount of fuel corresponding to this shortage amount is injected again.

[0006]

As described above, when predicting the intake air equivalent amount near the end of the intake stroke before that,
If the period from the time when the prediction calculation is performed to the prediction destination time is long, the error of the prediction value is likely to increase due to the influence of intake pulsation during steady operation. In other words, the fluctuation range of the actual intake air equivalent due to pulsation is relatively small, but the intake air equivalent is predicted in consideration of the fluctuation of the intake air equivalent from the prediction calculation time to the prediction destination time. It is predicted that the fluctuation of the intake air equivalent amount will increase as the period up to the preceding period increases. Therefore, the fluctuation range of the predicted value of the intake air equivalent becomes larger than the fluctuation range of the actual intake air equivalent due to the pulsation, and a calculation error occurs.

On the other hand, if the period from the time when the prediction calculation is performed to the prediction destination time is shortened, for example, the prediction destination time is set before the end of the intake stroke, the above period is shortened.
During a transition such as acceleration or deceleration, the actual intake air equivalent amount that increases or decreases until the end of the intake stroke does not sufficiently correspond to the predicted value, and an error occurs during the transition.

In the method disclosed in the above publication, after the fuel is injected based on the first prediction, the fuel is injected again so as to adjust the shortage of the fuel supply amount based on the second prediction. Although the accuracy is improved by this, the fuel injection based on the first prediction is relatively small because the fuel injection is performed again near the end of the intake stroke. If the quantity error is large, the adjustment cannot be completed, and it is difficult to sufficiently improve the accuracy of calculation and control with this alone.

In view of the above circumstances, the present invention predicts the intake air equivalent amount at the prediction destination time by calculation based on the detected value of the intake air equivalent amount, and changes the prediction calculation particularly in the steady state and the transient state. Accordingly, it is an object of the present invention to provide an engine control device that can accurately obtain a predicted value of the intake air amount in both the steady state and the transient state.

[0010]

The invention according to claim 1 is
A crank angle detecting means for detecting the crank angle of the engine and an intake air equivalent amount detecting means for detecting an amount corresponding to the intake air amount of the engine are provided, and the intake stroke is determined based on the value detected by the intake air equivalent amount detecting means. In an engine control device for predicting the intake air equivalent amount at a predetermined crank angle before the end of the crank angle after the crank angle, an operating state detecting means for detecting an operating state of the engine and the operation Based on the detection by both the state detection means and the crank angle detection means , the above calculation is performed when the steady operation state in the high rotation speed region is detected.
Based on the above detected value at the crank angle, from the end of the intake stroke
At a crank angle close to the crank angle at which the above calculation is performed.
The calculated value of the intake air equivalent amount is calculated , and when the transient operating state in the high speed region is detected , the above calculation is performed.
End of intake stroke based on the above detected value at the crank angle
And a predictive calculation changing means for changing so as to calculate a predicted value of the intake air equivalent amount at the crank angle .

[0011]

According to a second aspect of the invention, in the first aspect of the invention, there is provided fuel injection control means for controlling the fuel injection amount from the fuel injection valve provided in the engine in accordance with the predicted value of the intake air equivalent amount. It is a thing.

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

According to the apparatus of the action, in accordance with the claim 1 invention, when a transient in the high rotation region, the predicted value of the intake air amount corresponding at a crank angle of the intake stroke end on the basis of the detected value of the crank angle for performing upper Symbol operation by being computed, the actual predicted value of the intake air corresponding amount corresponding to the intake air amount corresponding to obtain at the time of transition, also, at the time of steady operation at a high rotation region, the detection of the crank angle for performing upper Symbol operation by predicted value of the intake air amount corresponding at a crank angle near the crank angle for performing the calculation than the intake stroke end on the basis of the value is calculated with respect to the variation width by the actual intake air amount corresponding to pulsation, intake air An increase in the fluctuation range of a considerable amount of the predicted value is suppressed. Therefore, the calculation error of the predicted value is reduced in each of the transient state and the steady state.

[0019]

By controlling the fuel injection amount according to the predicted value of the intake air equivalent amount (claim 2 ), the accuracy of the fuel injection amount control is improved.

[0021]

[0022]

[0023]

[0024]

[0025]

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 schematically shows an apparatus according to an embodiment of the present invention. In this figure, an intake port 4 and an exhaust port 5 are opened in a combustion chamber 2 of each cylinder of an engine 1, and ports 4 and 5 are provided.
In addition to the intake valve 6 and the exhaust valve 7, a spark plug 8 is provided.

An intake passage 9 communicating with the intake port 4 is provided with an air flow sensor 11 for detecting an intake flow rate and a throttle valve 12 which operates in response to an accelerator operation, and a fuel is provided near the intake port 4 of each cylinder. A fuel injection valve 13 for injecting and supplying is provided. on the other hand,
An exhaust passage 10 communicating with the exhaust port 5 is provided with an O ₂ sensor 14 for detecting an air-fuel ratio, an exhaust gas purification catalyst device 15, and the like.

A distributor 16 and an ignition coil 17 are connected to the ignition plug 8.
The distributor 16 has a crank angle sensor 18
And a cylinder discrimination sensor 19 are provided.

The air flow sensor 11 and the O ₂ sensor 1
4, signals from the crank angle sensor 18 and the cylinder discrimination sensor 19 are supplied to the control unit 2 for controlling the engine.
0 is input to the control unit 2 as well as signals from various sensors (not shown) that detect the water temperature, the intake air temperature, the throttle opening, etc. necessary for controlling the fuel injection amount.
It is input to 0. The control unit 20
Is a microcomputer or the like, inputs signals from the various sensors, outputs an injection pulse that is a signal for fuel injection control to the fuel injection valve 13, and corresponds to the pulse width of this injection pulse. Fuel injection valve 1 only for time
3 is opened.

FIG. 2 is a functional block diagram showing the means constituted by the control unit 20. The control unit 20 includes intake air equivalent amount detecting means 21 and first and second operation units for calculating a predicted value of intake air equivalent amount.
Computation means 22, 23, operating state detection means 24, predictive computation changing means 25 for changing the computation of the predicted value of the intake air equivalent amount according to the operating state, and computation of the estimated value of the intake air equivalent amount. It has a calculation timing setting means 26 for changing the timing to be performed according to the operating region, and a fuel injection control means 27 for controlling the fuel injection amount of the fuel injection valve 12.

The intake air equivalent amount detecting means 21 detects an amount corresponding to the intake air amount of the engine, and specifically,
The filling efficiency is obtained based on the detection signal of the air flow sensor 11.

The first and second calculating means 22 and 23 have a predicted filling efficiency (at a predicted time), which is a set period after the calculation time set by the calculation time setting means 26 as will be described later. The estimated value of the intake air equivalent amount) is calculated, and, for example, the charging efficiency (the detected value of the intake air equivalent amount) obtained by the intake air equivalent amount detection means 21 at the calculation time and its change rate are set. The predicted charging efficiency after the set period is calculated based on the period. However, the first calculation means 22 calculates the estimated filling efficiency after the first set period from the calculation time, and the second calculation means 23 after the second set period shorter than the first set period from the calculation time. Calculate the estimated charging efficiency of. In the present embodiment, the first calculation means 22 is 360 ° in relation to the fuel injection timing as described later.
The second filling means 23 calculates the predicted filling efficiency after CA.
Calculates the expected charging efficiency after 180 ° CA. Note that CA means a crank angle.

The operating state detecting means 24 detects the operating state in order to discriminate between the steady operating state and the transient operating state. For example, the change in the charging efficiency obtained by the intake air equivalent amount detecting means 21 is detected. Whether the transient operation state or the steady operation state is determined based on whether or not the amount (difference between the present value and the previous value) is larger than a predetermined threshold value. Further, in the present embodiment, the operating state detecting means 24 is the crank angle sensor 1
The engine speed is detected based on the signal from 8 and it is determined whether the engine speed is in a low speed range lower than the set speed or in a high speed range higher than the set speed. .

The predictive calculation changing means 25 predicts the intake air equivalent amount by using the second calculating means 23 based on the detection by the operating condition detecting means 24 when the steady operating condition is detected, and a predetermined value is obtained. When the transient operating condition is detected, the first calculating means 22 is used to predict the intake air equivalent amount. In the present embodiment, when the operating condition is in the low rotation region and in the steady operating condition in the high rotation region. The second computing means 23 is used for the above, and the first computing means 22 is used when in the transient operation state in the high rotation speed region.

The calculation timing setting means 25 sets the timing corresponding to the start timing of the fuel injection from the fuel injection valve 13 as the calculation timing, and sets this calculation timing (injection start timing) according to the operating condition. Specifically, the above calculation time is 180 ° from the end of the intake stroke in the low rotation speed region.
The timing is set to CA (second set time) before, and in the high rotation speed region, it is set to 360 ° CA (first set time) before the end of the suction stroke.

The fuel injection control means 27 causes the fuel injection valve 13 to inject fuel at the injection start timing according to the setting by the calculation timing setting means 26, and at the same time, the first calculation means 22 or the second calculation means. The fuel injection amount is controlled according to the predicted filling amount calculated by 23.

A specific example of fuel control by the control unit 20 will be described with reference to the flowchart of FIG.

The processing of this flow chart is carried out at a constant calculation cycle (for example, 4 ms). First, step S
1, the measured value Ga of the air flow sensor 11 is read, and in step S2, the engine rotation cycle (cycle between 180 ° CA) ts is obtained based on the signal of the crank angle sensor 18.
In step S3, the engine speed Ne is obtained by multiplying the reciprocal of the engine speed ts by a constant KT for converting the speed.

Next, as a process corresponding to the intake air equivalent amount detecting means 21, the charging efficiency of the intake air is obtained based on the air flow sensor measured value Ga, and specifically, the change of the air flow sensor measured value Ga and the actual In consideration of the time lag with the change in the amount of air taken into the combustion chamber, the apparent filling efficiency CeO corresponding to the air flow sensor measured value Ga is smoothed to obtain the net filling efficiency Ce. That is, the apparent filling efficiency CeO is calculated as CeO = Kga × Ga / Ne from the air flow sensor measured value Ga, the engine speed Ne, and the predetermined conversion constant Kga (step S4), and the net filling efficiency Ce is further calculated. Ce = Ka * Cel + (1-Ka) * CeO is calculated (step S5). Note that Ka is 0 <Ka <
The constant of 1, Cel is the previous net packing efficiency.

Next, in steps S6 to S13, the operation state detecting means 24, the prediction calculation changing means 25 and the calculation time setting means 26 are processed. More specifically, in step S6, the absolute value of the difference between the current net charging efficiency Ce and the previous net charging efficiency Cel is obtained as the charging efficiency change amount dce. Succeedingly, in a step S7, it is determined whether the engine rotational speed Ne is in the high rotational speed region or the low rotational speed region depending on whether or not the engine rotational speed Ne is higher than the set rotational speed KN.

If it is in the low rotation region (step S
If the determination in step 7 is NO), the predicted calculation time is set to 180 ° CA before the end of intake in step S8, and step S8 is performed.
In 9, the set period th from the prediction calculation time to the prediction destination time is set to 180 (° CA).

If it is in the high rotation region (step S
If the determination result in step 7 is YES), the predicted calculation time is set to 360 ° CA before the end of intake in step S10, and the set period th from the predicted calculation time to the prediction destination time is set to 360 (° CA) in step S11. If it is in this high rotation speed region, in step S12, it is further determined in step S12 whether transient operation or steady operation is performed depending on whether the charging efficiency change amount dce is larger than a predetermined threshold value KD. The predetermined set period th is maintained, and during steady operation, the set period th is set to 180 (° C) in step S13.
Change to A).

Next, in step S14, it is determined whether or not the predicted calculation time (the time set in step S8 or step S10) has come. Then, when the predicted calculation time comes, as a process of the first calculation means 22 or the second calculation means 23, the filling efficiency prediction coefficient γ is calculated (step S
15) The predicted charging efficiency Cef is calculated by multiplying the net charging efficiency Ce by this prediction coefficient γ (step S).
16).

The above prediction coefficient γ is the net filling efficiency C of this time.
e to the previous net filling efficiency Cel (Ce / Ce
l) is raised to the power of (ts / KCT) × (th / 180). Here, KCT is a calculation cycle (for example, 4 ms),
Further, as described above, ts is the engine rotation period, and ts is the set period from the prediction calculation time to the prediction destination time. The above (ts / KCT) × (th / 180) is the above set period t
It corresponds to the time corresponding to h. Therefore, the predicted filling efficiency Cef corresponds to the ratio (C
e / Cel) and the time corresponding to the set period th,
It becomes a value according to the net filling efficiency Cel of this time.

When the predicted charging efficiency Cef is obtained in this manner, subsequently, in step S17, the predicted charging efficiency Cef is multiplied by a predetermined constant KG to calculate the injection pulse width Ta corresponding to the fuel injection amount. Then, in step S18, the fuel injection valve 13 is controlled so that fuel is injected with the injection pulse width Ta.

In the case of the control apparatus according to the present embodiment as described above, the prediction calculation of the filling efficiency and the fuel injection timing and the period th from the prediction calculation timing to the prediction destination timing are in the low rotation range and at the high rotation range. FIG. 4 shows the transient operation in the region and the steady operation in the high rotation region.

That is, in the low rotation speed region, it is more advantageous to perform the predictive calculation and the fuel injection at a timing relatively close to the intake end timing, because it is advantageous to improve the accuracy of fuel control and fuel efficiency due to stratification. Prediction calculation and fuel injection are performed at a timing 180 ° CA before (intake TDC). Then, by setting the period th to 180 ° CA, the charging efficiency at the intake end timing is predicted, and the fuel injection amount is controlled according to the predicted charging efficiency.

On the other hand, in the high speed region, the actual time of the intake stroke is shortened, and if fuel injection is performed at the same timing as in the low speed region, a sufficient time for sending the fuel into the combustion chamber by the end of the intake stroke is secured. Therefore, the timing of the prediction calculation and the fuel injection is advanced as compared with the low rotation speed region, and it is set to 360 ° CA before the intake end timing. In this high rotation speed region, during transient operation, the period th is set to 360 ° CA so that the charging efficiency prediction destination time is the intake end time, but during steady operation, intake pulsation is predicted and calculated as described below. In order to avoid an increase in error due to the influence of the above, the period th is set to 180 ° CA which is shorter than that in the transient operation.

In this way, the prediction of the charging efficiency and the control of the fuel injection amount based on the prediction are accurately performed, and such an operation will be specifically described with reference to FIGS. 5 to 8. In the following description, 180 ° CA prediction means that the period th is 180 ° CA and the predicted charging efficiency is calculated, and 360 ° CA prediction means that the period th is 360 ° CA. It means that the predicted filling efficiency is calculated.

FIG. 5 shows the case in the low rotation region.
The graph shows the predicted value Ga of the air flow sensor, the charging efficiency, and the change in the predicted charging efficiency according to the change in the throttle opening. Further, FIG. 6 shows changes in the throttle opening, the air flow sensor predicted value Ga, the charging efficiency, the charging efficiency change amount, and the predicted charging efficiency in the high rotation speed region.

As shown in these figures, when the throttle opening changes, the intake flow rate detected by the air flow sensor 11 changes accordingly, and the charging efficiency changes. In this case, in steps S4 and S5, the apparent filling efficiency CeO corresponding to the predicted value Ga of the air flow sensor is annealed, whereby the net filling efficiency Ce corresponding to the actual filling efficiency is obtained.

When the engine speed is in the low rotation speed range, the predicted charging efficiency Cef is shown in FIG. 5 because the predicted calculation time is 180 ° CA before the suction end time and the 180 ° CA prediction is performed. Thus, the value becomes a value close to the charging efficiency Ce at the suction end timing, which is the prediction destination.

On the other hand, in the high rotation speed region, when the charging efficiency change amount dce shown in FIG. Is assumed to be 360 ° CA before the end of intake in both steady operation and transient operation, but 180 ° CA prediction is performed during steady operation and 360 ° CA prediction is performed during transient operation. The filling efficiency Cef changes as shown by the solid line in FIG. Note that when 360 ° CA prediction is performed during steady operation in the high rotation speed range, the predicted charging efficiency Cef changes as shown by the alternate long and short dash line, and the fluctuation becomes large. Further, when the 180 ° CA prediction is performed during the transient operation in the high rotation region, the predicted charging efficiency Cef changes as shown by the broken line, and the control delay corresponding to 180 ° CA occurs. On the other hand, according to the present embodiment, an appropriate predicted charging efficiency Cef can be obtained during steady operation at high rotation and during transient operation.

Prediction of the charging efficiency and control of fuel injection during the transient operation and the steady operation will be described more specifically with reference to FIGS. 7 and 8.

During the transient operation (for example, during acceleration), the actual charging efficiency Ce changes as shown by the solid line in FIG. 7, while the predicted charging efficiency Cef by 180 ° CA prediction is the broken line in the same figure. Predicted packing efficiency Ce by 360 ° CA prediction
f becomes like the dashed-dotted line in the figure. Then, the intake TD at which the fuel injection is started by performing the prediction calculation of the charging efficiency at the time (intake TDC) 180 ° CA before the intake end time.
In the case of C injection, the predicted charging efficiency CeB calculated by the 180 ° CA prediction at the predicted calculation timing is a value close to the charging efficiency CeA at the suction end timing. In addition, the timing before the end of inhalation by 360 ° CA (BTDC 180 ° CA)
BT that starts fuel injection by performing a prediction calculation of filling efficiency
In the case of DC 180 ° CA injection, 36 at the time of the prediction calculation.
The predicted charging efficiency CeC calculated by the 0 ° CA prediction is a value close to the charging efficiency CeA at the end of suction.

Also, during steady operation, the actual charging efficiency C
e is shown by the solid line in FIG. 8, while 180 °
The predicted filling efficiency Cef by CA prediction is the broken line 3 in the figure.
The predicted filling efficiency Cef by the 60 ° CA prediction is as shown by the alternate long and short dash line in the figure. As shown in this figure, the actual charging efficiency Ce during steady operation has a fluctuation due to pulsation, but the fluctuation range is relatively small, whereas the predicted charging efficiency Cef is relatively small.
The fluctuation range of becomes larger as the period to the prediction destination becomes longer.
That is, according to the 360 ° CA prediction in which the period to the prediction destination is long, the fluctuation range of the predicted filling efficiency Cef becomes large, and thus the proper injection pulse width Ta2 of the injection pulse width Ta2 calculated according to the predicted filling efficiency Cef is increased. (Injection amount according to the actual filling efficiency at the suction end timing) Ta1 has a large error. Compared to this, the period to the prediction destination is shorter 180 °
According to CA prediction, the fluctuation width of the predicted charging efficiency Cef is relatively small, and the error of the injection pulse width Ta3 calculated according to the predicted charging efficiency with respect to the proper injection pulse width Ta1 is small.

Therefore, during steady operation, not only in the intake TDC injection but also in the BTDC 180 ° CA injection, the accuracy by the 180 ° CA prediction is higher than that by the 360 ° CA prediction.

FIG. 9 shows a control operation according to another embodiment of the present invention. The control device for performing this control operation is shown in FIG.
The intake air equivalent amount detecting means 21, the first and second calculating means 22 and 23, the operating state detecting means 24, the predictive calculation changing means 25, the fuel injection control means 27, etc. shown in the figure The fuel injection controlled by 27 is divided into injection at the leading side injection timing and injection at the trailing side injection timing, and the fuel injection amount at each injection timing is the predicted value of the intake air equivalent amount. It is set according to. Then, the prediction of the filling efficiency for setting the injection amount at the leading side injection timing is performed by using the second calculating means 23 during the steady operation, and the first calculating means 22 during the transient operation.
It is supposed to be done using.

That is, as shown in FIG. 9, a predetermined leading side injection timing, for example, 3 from the intake end timing
The leading injection is performed at a timing 60 ° CA earlier, and the trailing injection is performed at a predetermined trailing-side injection timing, for example, a timing 180 ° CA earlier than the suction end timing.

At the time of leading injection, the predicted filling efficiency Cef is obtained by the prediction calculation, and the fuel injection amount is calculated accordingly. Then, for example, the amount obtained by subtracting the trailing injection possible amount from the fuel injection amount or the amount obtained by multiplying the fuel injection amount by a predetermined distribution ratio is set as the leading injection amount, and the leading injection is performed. In addition, even in the case of trailing injection, the prediction filling efficiency C
ef is obtained, and the fuel injection amount is calculated accordingly. The amount obtained by subtracting the leading injection amount from the fuel injection amount is set as the trailing injection amount, and the trailing injection is performed.

In the predictive calculation at the time of the above leading injection, the predictive charging efficiency Cef is obtained by a calculation process such as steps S14 and S15 in the flow chart of FIG. 3 above. The th is changed between the transient operation and the steady operation, and th = 360 (° CA) during the transient operation and th = 180 (° CA) during the steady operation. In the prediction calculation at the time of trailing injection, th = 180 (° C
A), and the predicted filling efficiency is obtained by the above-mentioned arithmetic processing.

According to this embodiment, the split injection is performed, which is advantageous for improving combustion stability and stratification. In addition, the predicted charging efficiency Cef is calculated during the leading injection and the trailing injection, and the injection amount is set based on the calculated predicted charging efficiency Cef, so that the accuracy of control of the fuel injection amount is improved.

In particular, in the predictive calculation in the leading injection in which the period up to the intake end timing is relatively long, the period th up to the predicted destination timing is changed as described above between the transient operation and the steady operation. As a result, as described above, the accuracy of the calculation of the predicted filling efficiency and the control of the injection amount based on the calculation of the predicted charging efficiency are improved during the transient operation and the steady operation. Although the error in the leading injection amount is adjusted to some extent in the trailing injection amount, it cannot be adjusted when the error in the leading injection amount becomes large. Increasing precision is useful.

FIG. 10 shows a control operation according to still another embodiment of the present invention. The control device for performing this control operation is the intake air equivalent amount detecting means 21 shown in FIG.
The fuel injection controlled by the fuel injection control means 27 is the leading in the low rotation speed region. Injection at the side injection timing (for example, 360 ° CA before the end of suction) and trailing side injection timing (for example, 180 ° C before the end of suction)
The injection is performed separately from the injection at the timing A), and is performed only at the leading-side injection timing in the high rotation speed region.

Then, in the low rotation speed region, the prediction calculation is performed at least during the trailing injection. For example, during the leading injection, the predictive calculation is not performed, but the fuel injection amount is calculated according to the filling efficiency at that time, and the leading injection amount is set based on the calculated fuel injection amount. = 180 (° CA), the predicted filling efficiency is obtained by the above-described calculation process, the fuel injection amount is calculated accordingly, and the amount obtained by subtracting the leading injection amount from the fuel injection amount is the trailing injection amount. Then, trailing injection is performed.

Further, in the high rotation speed region, the predicted filling efficiency Cef is obtained by the above-mentioned calculation processing at the time of injection at the timing corresponding to the leading side injection timing, and the fuel injection amount is calculated in accordance with it. Fuel injection is performed with the fuel injection amount. In this case, the period th up to the prediction destination time is changed between the transient operation and the steady operation, and th = 360 (° CA) during the transient operation and th = 180 (° CA) during the steady operation.

According to this embodiment, split injection is performed in the low rotation speed region. In this case, the prediction calculation is not performed in the leading injection, but the error in the leading injection amount is adjusted by the trailing injection amount. In this trailing injection, the fuel injection amount is accurately controlled based on the above prediction calculation. Further, in the high rotation speed region, the actual time of the intake stroke is shortened, and the error of the leading injection amount may not be adjusted by the trailing injection amount. Therefore, fuel injection is performed only at the leading side injection timing. At this time, the prediction calculation of the filling efficiency is performed.
In particular, the period th up to the prediction destination time is changed as described above between the transient operation and the steady operation, so that the predicted filling efficiency is calculated in the transient operation and the steady operation as described above. The accuracy of the injection amount control based on it is improved.

[0067]

As described above, according to the present invention, based on the detected value of the intake air equivalent amount at the crank angle for which the calculation is performed, in the steady operation state in the high rotation region, from the end of the intake stroke.
At a crank angle close to the crank angle at which the above calculation is performed.
The predicted value of the intake air equivalent amount is calculated , and the crank at the end of the intake stroke is entered during transient operation in the high rotation speed region.
Since the predicted value of the intake air equivalent amount at the corner is calculated , the intake air equivalent amount can be properly predicted. In particular, at the time of steady operation, by shortening the period from the crank angle that performs the calculation for predicting the intake air equivalent amount to the predicted crank angle, the fluctuation range due to the pulsation of the actual intake air equivalent amount It is possible to suppress an increase in the fluctuation range of the predicted value of the intake air equivalent amount, and to calculate the predicted value of the intake air equivalent amount that allows for changes in the intake air equivalent amount during a predetermined transient operation. It is possible to improve the accuracy of prediction value calculation during steady operation and transient operation.

In this device, if the fuel injection amount is controlled according to the predicted value of the intake air equivalent amount, the accuracy of the fuel injection amount control can be improved.

[0069]

[0070]

[0071]

[Brief description of drawings]

FIG. 1 is a schematic diagram of an engine including a control device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a control system.

FIG. 3 is a flowchart showing a specific example of control.

FIG. 4 is an explanatory diagram showing a control operation of the control device.

FIG. 5 is a timing chart showing changes in throttle opening, airflow sensor measurement value, filling efficiency, and predicted filling efficiency in a low rotation speed region.

FIG. 6 is a timing chart showing changes in throttle opening, air flow sensor measurement value, charging efficiency, charging efficiency change amount, and predicted charging efficiency in a high rotation region.

FIG. 7 is an explanatory diagram showing changes in charging efficiency and predicted charging efficiency during transient operation, fuel injection timing, and the like.

FIG. 8 is an explanatory diagram showing changes in filling efficiency and predicted filling efficiency during normal operation, fuel injection timing, and the like.

FIG. 9 is an explanatory diagram showing a control operation of another control device.

FIG. 10 is an explanatory diagram showing a control operation of still another control device.

[Explanation of symbols]

1 engine body 11 Air flow sensor 13 Fuel injection amount 20 control unit 21 Intake air equivalent amount detection means 22 First computing means 23 Second computing means 24 Operating state detection means 25 Prediction calculation change means 26 Calculation time setting means 27 Fuel injection control means

Continuation of the front page (56) Reference JP-A-4-246258 (JP, A) JP-A-2-30958 (JP, A) JP-A-1-134041 (JP, A) JP-A-62-214241 (JP , A) JP-A-62-206245 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 41/00-41/40, 45/00

Claims (2)

(57) [Claims] 1. A crank angle detecting means for detecting a crank angle of an engine, and an intake air equivalent amount detecting means for detecting an amount corresponding to an intake air amount of an engine, wherein a value detected by the intake air equivalent amount detecting means is provided. Based on the above, the engine control device detects the operating state of the engine in the engine control device that predicts the intake air equivalent amount at the predetermined crank angle before the end of the intake stroke and at the crank angle after that crank angle. Based on the detections of both the operating state detecting means and the operating angle detecting means and the crank angle detecting means, when the steady operating state in the high rotation region is detected , the above-mentioned calculation is performed at the crank angle.
Based on the detected value, the above calculation is performed from the end of the inhalation stroke.
Predicting intake air equivalent at crank angle close to rank angle
When the measured value is calculated and a transient operating state in the high speed region is detected , the crank angle at which the above calculation is performed is changed.
Based on the above detected values, at the crank angle at the end of the intake stroke
A control device for an engine, comprising: a predictive calculation changing means for changing a predictive value of an intake air equivalent amount . 2. The engine according to claim 1, further comprising fuel injection control means for controlling a fuel injection amount from a fuel injection valve provided in the engine according to a predicted value of the intake air equivalent amount. Control device.