JP2005023943A - Engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control for controlling matching in phase of fuel injection with air suction in an engine control device for controlling a suction air amount on the basis of torque or a fuel injection amount. <P>SOLUTION: In determining control of a reference pulse width as the basis for a fuel injection pulse width corresponding to an operating condition except for a suction air amount, a filtering reference pulse width is computed with the temporal filtering of the reference pulse width and the fuel injection amount is computed in accordance with the filtering reference pulse width. In computing control of a target throttle opening in conformity with feedback control, a feedback constant is changed in accordance with the operating condition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an engine control device that controls an intake air amount with reference to torque and fuel injection amount, and more particularly to a control device that obtains a suitable air-fuel ratio in any operating state.

  As conventional engine control, for example, as described in Patent Document 1, at least two parameters of a fuel injection timing, an air-fuel ratio, an ignition timing, and an air amount are determined based on a target torque calculated according to an operating state. In addition, a control has been developed that performs fuel injection and improves fuel consumption and driving feeling.

JP-A-7-301139

  By the way, there is no description about the timing of fuel injection and air intake in the control of Patent Document 1, and in particular during the transient operation when the intake air amount is controlled based on the torque and the fuel injection amount, There is a risk of air-fuel ratio fluctuations, drivability and exhaust deterioration due to delayed response of air intake.

  The problems to be solved by the present invention are, in particular, in an engine control device that controls the intake air amount based on torque and fuel injection amount, fluctuations in air-fuel ratio due to delay in response of air intake to fuel injection, operability, It is to suppress the deterioration of exhaust.

  The above problem is solved by matching the phases of fuel injection and air intake. In order to match the phases of fuel injection and air intake, there are a method of delaying fuel injection and a method of speeding up air intake.

  The former applies a temporal filter to the fuel injection amount. Specifically, reference pulse width calculation means for calculating a reference pulse width as a reference when calculating the fuel injection pulse width according to the operating state, and target air-fuel ratio calculation for calculating the target air-fuel ratio according to the operating state Means, target throttle opening calculating means for calculating the target throttle opening according to the operating state including the target air-fuel ratio, and fuel injection phase correction for calculating the filtering reference pulse width by applying a temporal filter to the reference pulse width A fuel injection amount is calculated based on the filtering reference pulse width, and fuel injection control is performed.

  The latter uses an electronically controlled throttle for controlling the intake air amount, and further changes the feedback constant when feedback control is performed on the opening of the electronically controlled throttle. Specifically, reference pulse width calculation means for calculating a reference pulse width as a reference when calculating the fuel injection pulse width according to the operating state, and target air-fuel ratio calculation for calculating the target air-fuel ratio according to the operating state And a target throttle opening calculating means for calculating a target throttle opening according to an operating state including a target air-fuel ratio. Intake air amount calculating means for calculating, target air amount calculating means for calculating the target air amount, and target throttle opening feedback for calculating the target throttle opening in accordance with feedback control for causing the cylinder intake air amount to follow the target air amount Feed that sets the feedback constant of the calculation means and the target throttle opening feedback calculation means according to the operating state Tsu providing a click constant setting means.

  In particular, during transient operation in an engine control device that controls intake air amount based on torque and fuel injection amount, changes in fuel injection amount are immediately reflected in the fuel injection device, while changes in cylinder intake air amount Is delayed from the change in the fuel injection amount due to the time delay required to pass through the intake pipe and the time delay required to change the pressure in the intake pipe. In response to this problem, when a time filter is applied to the fuel injection amount, or when an electronically controlled throttle is used to control the intake air amount and the opening degree of the electronically controlled throttle is further feedback controlled, the feedback constant is changed. As a result, the phases of fuel injection and air intake can be matched, and fluctuations in the air-fuel ratio, drivability, and exhaust deterioration can be suppressed.

  The present invention relates to an engine control device, particularly an engine control device that controls the intake air amount based on torque and fuel injection amount, and sets a reference pulse width KTP, which is a reference when calculating the fuel injection pulse width, according to the operating state A reference pulse width calculating means for calculating the reference value, a fuel injection phase correcting means for calculating a filtering reference pulse width FKTP by applying a temporal filter to the reference pulse width KTP, and calculating a fuel injection amount based on the filtering reference pulse width FKTP. By performing fuel injection control, discrete changes in the fuel injection amount can be prevented during transient operation, and the phase of fuel injection and air intake can be matched to suppress fluctuations in air-fuel ratio, drivability and exhaust deterioration. can do. Further, in an engine control apparatus provided with a target throttle opening feedback calculating means for calculating a target throttle opening tTH in accordance with feedback control, feedback for setting a feedback constant of the target throttle opening feedback calculating means in accordance with an operating state. By providing the constant setting means, the responsiveness of the air amount can be accelerated during transient operation, the phases of fuel injection and air intake can be matched, and fluctuations in air-fuel ratio, drivability and exhaust deterioration can be suppressed. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 2 shows an example of an engine system to which the present invention is applied. In FIG. 2, the air taken in by the engine is taken in from the inlet 202 a of the air cleaner 202, passes through the intake air temperature sensor 225, the air flow rate sensor 203, passes through the throttle body in which the throttle valve 205 that controls the intake flow rate is accommodated, and the collector 206 to go into. An intake pipe pressure sensor 224 is provided on the cylinder side of the throttle body. The intake air is distributed to each intake pipe connected to each cylinder of the engine 207 and guided into the cylinder.

On the other hand, fuel such as gasoline is primarily pressurized from the fuel tank 214 by the fuel pump 210 and then secondarily pressurized by the fuel pump 211 and supplied to the fuel system in which the injector 209 is piped. The primary pressurized fuel is regulated to a constant pressure (for example, 3 kg / cm ² ) by the fuel pressure regulator 212, and the secondarily pressurized fuel is regulated to a higher pressure by the fuel pressure regulator 213 (for example, 50 kg / cm ² ). cm ² ), and injected into the cylinders from the injectors 209 provided in the respective cylinders. The injected fuel is ignited by the spark plug 208 by the ignition signal that has been increased in voltage by the ignition coil 222.

  The control unit 215 receives a signal representing the intake air temperature from the intake air temperature sensor 225, a signal representing the intake air flow rate from the air flow sensor 203, and a signal representing the intake pipe internal pressure from the intake pipe pressure sensor 224. Is done. A throttle sensor 204 for detecting the opening of the throttle valve 205 a is attached to the throttle body, and its output is also input to the control unit 215.

  Reference numeral 216 denotes a crank angle sensor attached to the camshaft shaft, which outputs a reference angle signal REF indicating the rotation position of the crankshaft and an angle signal POS for detecting a rotation signal (rotation speed). These signals are also controlled by the control unit 215. Is input.

Reference numeral 218 denotes an A / F sensor provided before the catalyst 220 in the exhaust pipe 219, and this output signal is also input to the control unit 215. In addition, a fuel pressure sensor 223 is provided in the pipe to be secondarily pressurized, and an output signal thereof is also input to the control unit 215.

  As shown in FIG. 3, the main part of the control unit 215 includes an MPU 301, a ROM 302, a RAM 303, an I / O LSI 304 including an A / D converter, etc., and signals from various sensors that detect the operating state of the engine. Is input as an input, predetermined calculation processing is executed, various control signals calculated as the calculation results are output, predetermined control signals are supplied to the above-described injector 209 and ignition coil 222, and fuel supply amount control is performed. Ignition timing control is executed.

  FIG. 4 shows a block diagram of the fuel injection control and the air intake control executed by the control unit 215 in the cylinder injection engine as described above. FIG. 4 shows six blocks including a reference pulse width calculating means 401, a target air-fuel ratio calculating means 402, an intake air amount calculating means 403, a target air amount calculating means 404, a target throttle opening calculating means 405, and a fuel injection phase correcting means 406. However, as another configuration in the present invention, either or both of the intake air amount calculation means 403 and the target air amount calculation means 404 may be deleted.

  The configuration of FIG. 1 is an example using all of the configuration of FIG. 4, and FIG. 1 will be described in detail below.

  First, the reference pulse width calculation means 101 obtains a reference pulse width KTP by referring to a map from the accelerator opening Acc and the engine speed Ne. The reference pulse width KTP is a reference value for calculating the fuel injection pulse width TI, and the fuel injection pulse width TI is calculated by, for example, equation (1).

(Equation 1)
TI = KTP × COEF × GAMMA (1)
Here, COEF is an open-loop fuel correction coefficient that operates depending on operating conditions such as transient correction and post-startup correction, and GAMMA is an air-fuel ratio feedback coefficient.

  The target air-fuel ratio calculating means 102 obtains the target air-fuel ratio tAF by referring to a map from the engine speed Ne and the reference pulse width KTP.

The intake air amount calculation means 103 calculates the cylinder intake air amount rQa from the throttle passage air amount rQt which is the airflow sensor output. Details of this control are shown in FIG.

  First, the airflow sensor output is converted into the throttle passage air amount rQt by the voltage-mass flow rate conversion table 501. From the converted throttle passing air amount rQt, cylinder intake air amount rQa, and intake pipe pressure previous calculation value rPa [-dt], the intake pipe pressure estimating means 502 calculates the intake pipe pressure rPa. The expression of the intake pipe pressure estimating means 502 is obtained as follows.

  The pressure gradient of the intake pipe pressure is proportional to the difference between the throttle passage air amount rQt and the cylinder intake air amount rQa. Equation (2) shows this, and its proportionality coefficient K1 is derived from the ideal gas equation of state and can be expressed as equation (3).

  Here, R is a gas constant, Ta is the intake air temperature, M is the average molecular weight of air, and V is the volume from the throttle to the cylinder. When this expression (2) is developed for digital processing, expression (4) is obtained, and the intake pipe pressure rPa is calculated based on expression (4).

(Equation 4)
rPa = rPa [−dt] + dt × KI × (rQt−rQa) (4)
The cylinder intake air amount calculation unit 503 calculates the cylinder intake air amount rQa from the intake pipe internal pressure rPa calculated by the intake pipe internal pressure estimation unit 502 and the engine speed Ne. The setting of the map of the cylinder intake air amount calculation means 503 is performed based on the equation (5), and the equation (5) is derived from the ideal gas state equation.

  Here, D is the engine displacement, and η is the charging efficiency. FIG. 6 shows a flowchart for calculating the intake air amount of FIG.

The effect of the control shown in FIG. 5 will be described. FIG. 7 shows an example of the intake pipe model. In particular, during transition, the throttle passage air amount rQt and the cylinder intake air amount rQa do not coincide with each other due to the volume of the intake pipe. Specifically, the throttle passage air amount rQt at the time of acceleration is larger than the cylinder intake air amount rQa because extra air is required for filling the intake pipe, and the throttle passage air amount rQt at the time of deceleration is filled in the intake pipe. Since a part of the air flows into the cylinder, it becomes smaller than the cylinder intake air amount rQa. On the other hand, the control shown in FIG. 5 can model the time variation of the intake pipe pressure rPa, and therefore can absorb the discrepancy between the throttle passage air amount rQt and the cylinder intake air amount rQa caused by the intake pipe volume. The cylinder intake air amount rQa can be calculated.

  Next, in the target air amount calculation means 104, an equation (6) is obtained from the reference pulse width KTP calculated by the reference pulse width calculation means 101, the target air-fuel ratio tAF calculated by the target air-fuel ratio calculation means 102, and the engine speed Ne. ) To calculate the target air amount tQa.

(Equation 7)
K2 = K3 × f (FP) (7)
Here, K2 is obtained by the equation (7), and K3 is an actual basic pulse from the cylinder intake air amount rQa and the engine speed Ne of the equation (8) known in the conventional intake port injection (MPI) control. This is a conversion coefficient for obtaining the width rTP. Further, FP is the fuel pressure, and K2 includes a correction for the fuel pressure according to f (FP).

  Next, in the target throttle opening calculation means 105, the target throttle according to the deviation between the target air amount tQa calculated by the target air amount calculation means 104 and the cylinder intake air amount rQa calculated by the intake air amount calculation means 103. The opening degree tTH is feedback controlled. Here, the actuator controlled by the target throttle opening tTH is assumed to be an electronically controlled throttle.

  The configuration of the target throttle opening calculation means 105 is shown in FIG. First, the air amount deviation eQa is obtained by subtracting the cylinder intake air amount rQa from the target air amount tQa. The gain obtained in block 801 is multiplied by the air amount deviation eQa to obtain a proportional amount of feedback control, and the air amount deviation eQa is differentiated by a differentiator 802 and a differential gain is obtained in block 803 to obtain a differential amount. The integral is obtained by multiplying the amount deviation eQa by the integrator 804 with the integral gain in the block 805, and the integral is obtained as the target throttle opening tTH. FIG. 9 shows a flowchart for calculating the target throttle opening in FIG.

  The feedback control of the target throttle opening tTH has the advantage that the matching man-hours can be greatly reduced and the cylinder intake air amount rQa can be accurately controlled to the target air amount tQa. Further, in this example, the time variation of the intake pipe pressure is modeled, and the mismatch between the throttle passage air amount rQt and the cylinder intake air amount rQa generated due to the volume of the intake pipe is absorbed. Since rQa can be used as an index, the accuracy of throttle control can be improved.

Next, the configuration of the fuel injection phase correction means 106 is shown in FIG. The cylinder intake air amount rQa calculated by the intake air amount calculation means 103 and the cylinder intake air amount previous calculation value rQa
Based on [−dt] and the target air amount tQa calculated by the target air amount calculating means 104, the air response time constant calculating means 1001 calculates the air response time constant α of the cylinder intake air amount rQa based on the equation (9). To do. Then, the phase correction means 1002 calculates the filtering reference pulse width FKTP based on the equation (10) using the air response time constant α as a temporal filter. FIG. 11 shows a flowchart of control for correcting the phase of fuel injection in FIG.

The meanings of Equation (9) and Equation (10) will be described with reference to FIG. At a certain calculation timing, the point B is set with respect to the points A and C from the target air amount tQa at the point A, the cylinder intake air amount rQa at the point B, and the cylinder intake air amount at the point C previously calculated value rQa [-dt]. The ratio of proportional distribution to be determined is calculated. Based on the ratio, the reference pulse width KTP at the point D and the filtering reference pulse width at the previous point FKTP [-dt] are proportionally distributed to calculate the filtering reference pulse width FKTP at the point X.

  The fuel injection pulse width TI to be finally injected is calculated based on the filtering reference pulse width FKTP of the equation (11), not the reference pulse width KTP of the equation (1), and matched with the phase of the cylinder intake air amount rQa. Perform fuel injection.

(Equation 11)
TI = FKTP × COEF × GAMMA (11)
The above is the detailed description based on the configuration of FIG.

The effect of the control shown in FIG. 1 is shown in FIG. Here, a case where the accelerator is opened in a cylinder injection engine that controls the intake air amount based on the torque and the fuel injection amount is considered. First, FIG. 13A shows a case where the control shown in FIG. 1 is not performed. In this case, the fuel injection amount is calculated based on the reference pulse width KTP without phase correction based on the equation (1). While the change in the fuel injection amount according to the change in the reference pulse width KTP is immediate, the change in the cylinder intake air amount rQa according to the target air amount tQa is caused by the time delay required for passing through the intake pipe and the intake air Due to the time delay required for the change in the pressure in the pipe, there is a region where the phase of the fuel and air is out of phase due to the delay from the change in the fuel injection amount. For this reason, there is a possibility that the air-fuel ratio becomes rich, combustion deteriorates, drivability deteriorates, and in the worst case, the engine stops. Next, FIG. 13B shows a case where the control shown in FIG. 1 is performed. The control shown in FIG. 1 calculates the cylinder intake air amount rQa with high accuracy, calculates the air response time constant α from the temporal change of the cylinder intake air amount rQa, and sets the air response time constant α to the reference pulse width KTP. Based on the fuel injection phase correction, the filtering reference pulse width FKTP is calculated. In this case, the fuel injection amount is calculated based on the filtering reference pulse width FKTP in which phase correction is performed based on the equation (11). As a result, the phases of fuel injection and air intake can be accurately matched, and the air-fuel ratio can be controlled to be constant even during transient operation. Controlling the air-fuel ratio to a constant leads to suppression of drivability and exhaust deterioration.

  FIG. 13B also shows a change in the filtering reference pulse width FKTP when the target air-fuel ratio tAF is switched. In the fuel injection phase correction based on the equation (10), the filtering reference pulse width FKTP does not change unless the reference pulse width KTP changes. Therefore, even if the target air-fuel ratio tAF changes and the cylinder intake air amount rQa increases, the filtering reference The pulse width FKTP does not change. That is, it is possible to eliminate the change in the fuel injection amount due to the switching of the target air-fuel ratio tAF, that is, the occurrence of torque shock.

  In the following, examples that can be selected in place of FIG. 1 are listed for each block shown in FIG.

With respect to the intake air amount calculation means 403, the throttle passage air amount rQt is not detected by the air flow sensor as shown in FIG. 5, but the engine speed Ne and the actual throttle opening degree rTH are It may be obtained by referring to the map. Further, instead of the intake pipe pressure estimation means 502 of FIG. 5, an intake pipe pressure sensor is arranged as shown in FIG. 15, and the value detected by the intake pipe pressure sensor is set as the intake pipe pressure rPa to the cylinder intake air amount calculation means 503. May be input. Further, instead of the cylinder intake air amount calculating means 503 in FIG. 5, the calculated value xQa is calculated based on the expression obtained by removing the charging efficiency η in the expression (5) in the block 1601 as shown in FIG. In parallel charging efficiency calculation means 1602, for example, a charging efficiency η is obtained by referring to a map with the engine speed Ne and the actual throttle opening rTH as axes, and the calculated value xQa is multiplied by the charging efficiency η to obtain the cylinder intake air amount. rQa may be obtained. Further, the charging efficiency η may be modeled, and the cylinder intake air amount calculation means 503 may be replaced with one linear form.

  Further, in the intake air amount calculation means 403, the control shown in FIG. 5 is not used, and the throttle passage air amount rQt may be used as it is as the cylinder intake air amount rQa. The cylinder intake air amount rQa may be obtained by applying a filter having a time constant β shown.

Next, regarding the target air amount calculation means 404, the reference pulse width KTP in equation (6) is replaced with the fuel injection pulse width TI, in addition to calculating the target air amount tQa according to the linear form of equation (6). The target air amount tQa may be calculated based on the linear format. In addition, as shown in FIG. 17, the stoichiometric target air amount calculating means 1701 calculates a stoichiometric target air amount tSQa with reference to a map with the engine speed Ne and the reference pulse width KTP as axes, and obtains the stoichiometric target air amount tSQa. A method of calculating the target air amount tQa by multiplying by the target air-fuel ratio tAF and further dividing by the stoichiometric air-fuel ratio 14.7 may be used.

Next, with respect to the target throttle opening degree calculation means 405, a method of performing feedback calculation of the target throttle opening degree tTH based on the air amount deviation eQa that is the difference between the target air amount tQa and the cylinder intake air amount rQa as shown in FIG. In addition, as shown in FIG. 18, a method of converting the target air amount tQa calculated by the target air amount calculating means 404 into the target throttle opening degree tTH according to the air amount opening degree conversion table 1801 can be considered.

  In addition, as another example of the target throttle opening calculation means 405, two examples will be described below.

  FIG. 19 shows the control of the first example. In the control shown in FIG. 19, first, the throttle opening corresponding to the rotational speed feedback correction corresponding to the rotational speed feedback correction for causing the rotational speed during idling to follow the target rotational speed is calculated. The deviation eNe between the target rotational speed tNe and the engine rotational speed Ne is taken, the gain obtained in block 1901 is multiplied by the deviation eNe to obtain the proportional part of PID control, and the deviation eNe is differentiated by the differentiator 1902 and differentiated by the block 1903 A gain is applied to obtain a differential component, and an integral gain is obtained by applying an integral gain to block 1905 obtained by integrating the deviation eNe by an integrator 1904, and a proportional component, a differential component, and an integral component are calculated. Then, the sum of the three components proportional, differential and integral is calculated as the throttle opening corresponding to the rotational speed feedback correction. On the other hand, in block 1906, the throttle opening corresponding to the load is calculated according to the load SW corresponding to the on / off of the load such as the air conditioner, the power steering, the electric load (current consumption), and the electric radio fan. In block 1907, an accelerator equivalent throttle opening is calculated based on the accelerator opening Acc. The sum of the throttle opening corresponding to the rotational speed feedback correction, the throttle opening corresponding to the load, and the throttle opening corresponding to the accelerator is calculated, and further multiplied by the target air-fuel ratio tAF and divided by the stoichiometric air-fuel ratio 14.7 to obtain the target throttle opening tTH. . FIG. 20 shows a flowchart for calculating the target throttle opening in FIG.

  The control of the second example is shown in FIG. In the control shown in FIG. 21, first, the actual basic pulse width rTP is calculated from the cylinder intake air amount rQa calculated by the intake air amount calculation means 403 in block 2101 and the engine speed Ne based on the above equation (8). To do. On the other hand, the target basic pulse width tTP is calculated from the reference pulse width KTP, the target air-fuel ratio tAF, and the stoichiometric air-fuel ratio 14.7 based on the equation (13).

Then, the deviation eTP between the target basic pulse width tTP and the actual basic pulse width rTP is taken, the gain obtained in the block 2102 is multiplied by the deviation eTP to obtain the proportional portion of PID control, and the deviation eTP is differentiated by the differentiator 2103. In block 2104, the differential gain is applied to obtain the differential component, and the deviation eTP is integrated by the integrator 2105, and the integral gain is applied in block 2106 to obtain the integral component, and the sum of the proportional component, the differential component, and the integral component is obtained as the target throttle. Calculated as the opening degree tTH. FIG. 22 shows a flowchart for calculating the target throttle opening degree of FIG.

  Further, the actuator that performs the operation of the target throttle opening tTH calculated by the target throttle opening calculation means 405 may be an electronic control throttle.

  Next, three examples of the fuel injection phase correcting means 406 will be described below.

FIG. 23 shows the control of the first example. In the control shown in FIG. 23, first, in block 2301, the actual basic pulse width rTP is calculated from the cylinder intake air amount rQa and the engine speed Ne based on the equation (8). On the other hand, by multiplying the reference pulse width KTP by the target air-fuel ratio tAF, the stoichiometric air-fuel ratio
The value divided by (14.7) is calculated as the target basic pulse width tTP. The response time constant α of the actual basic pulse width rTP is calculated from the actual basic pulse width rTP, the actual basic pulse width previously calculated value rTP [−dt], and the target basic pulse width tTP by the response time constant calculating means 2302 based on the equation (14) Is calculated.

Then, the phase correction means 2303 calculates the filtering reference pulse width FKTP based on the equation (10) using the air response time constant α as a temporal filter. FIG. 24 shows a flowchart of control for correcting the phase of fuel injection in FIG.

The control in the second example is a method in which the ratio between the cylinder intake air amount rQa and the target air amount tQa is used as a temporal filter. Specifically, a ratio between the cylinder intake air amount rQa calculated by the intake air amount calculation unit 103 and the target air amount tQa calculated by the target air amount calculation unit 104 is obtained based on the equation (15), and the ratio is calculated. The filtering reference pulse width FKTP is calculated by multiplying the reference pulse width KTP calculated by the reference pulse width calculation means 101.

  The ratio between the cylinder intake air amount rQa and the target air amount tQa is a correction term corresponding to the temporal change of the cylinder intake air amount rQa with respect to the target air amount tQa, and serves as a temporal filter for the reference pulse width KTP. By this term, even if the reference pulse width KTP changes suddenly during the transition, the filtering reference pulse width FKTP can be matched with the phase of the cylinder intake air amount rQa.

Further, in the method in which the ratio between the cylinder intake air amount rQa and the target air amount tQa is a temporal filter based on the equation (15), when a certain condition is satisfied, the reference pulse width KTP is directly used as the filtering reference pulse width FKTP. Also good. FIG. 26 is a block diagram including conditions in FIG. A condition 2501 that the target air-fuel ratio tAF is within the range of the delay time DlyAF after switching is satisfied, and the ratio of the cylinder intake air amount rQa and the target air amount tQa is within the range of the threshold AFTH1 or less or the threshold AFTH2 or more. If the condition 2502 is satisfied, the reference pulse width KTP is directly used as the filtering reference pulse width FKTP by the block 2503. On the other hand, if either condition 2501 or condition 2502 is not satisfied, the filtering reference pulse width FKTP is obtained by multiplying the reference pulse width KTP by the ratio of the cylinder intake air amount rQa and the target air amount tQa based on the equation (15). Calculate. In AFTH1 and AFTH2, for example, AFTH1 is set to 95% and AFTH2 is set to 105%.

  The effect of the control shown in FIG. 25 is shown in FIG. Looking at changes in each variable before and after the target air-fuel ratio tAF switching, the reference pulse width KTP does not change, but the target air amount tQa changes according to the target air-fuel ratio tAF switching. The cylinder intake air amount rQa also changes to follow the target air amount tQa. The change of the filtering reference pulse width FKTP before and after the target air-fuel ratio tAF switching at this time is first determined when the control of the equation (15) shown in FIG. 26 (a) is performed unconditionally and the cylinder intake air amount rQa and the target It becomes smaller under the influence of the ratio to the air amount tQa. For this reason, the fuel injection amount decreases before and after the target air-fuel ratio tAF switching, and a torque shock occurs. On the other hand, in this case, the reference pulse width KTP does not change before and after the target air-fuel ratio tAF switching, but when the control of FIG. 25 shown in FIG. 26B is performed, the target air-fuel ratio tAF is changed before and after the target air-fuel ratio tAF switching. Both the condition 2501 that the delay time DlyAF is within the range after switching and the condition 2502 that the ratio of the cylinder intake air amount rQa and the target air amount tQa is within the threshold AFTH1 or less or the threshold AFTH2 are established. Therefore, the filtering reference pulse width FKTP becomes equal to the reference pulse width KTP and does not change before and after the target air-fuel ratio tAF switching. For this reason, the fuel injection amount is constant before and after the target air-fuel ratio tAF switching, and no torque shock occurs.

  In the third control, a constant is used as a temporal filter. Specifically, the constant setting reference pulse width KTP is delayed by the delay time Dly to obtain the filtering reference pulse width FKTP, or the filtering is performed from the reference pulse width KTP based on the first-order delay time constant γ. There is a method shown in Expression (17) for obtaining the reference pulse width FKTP.

(Equation 16)
FKTP = KTP [−Dly] (16)

  Further, there are two methods for setting the delay time Dly and the first-order delay time constant γ depending on the difference between idle and off-idle, accelerator opening Acc, actual throttle opening rTH, and cylinder intake air amount rQa. A method of switching to any of the set values, a method of obtaining with reference to a table with the gear position, engine speed Ne, actual throttle opening degree rTH, cylinder intake air amount rQa as an axis, engine speed Ne and actual throttle opening degree rTH And a map with the engine speed Ne and the cylinder intake air amount rQa as axes.

  In addition, a value learned based on the operating state may be used as the temporal filter value in the fuel injection phase correcting means 406. As a method of learning the filter value over time, for example, the time from when the target throttle opening tTH changes until the cylinder intake air amount rQa changes is learned as the delay time Dly, or the target throttle opening tTH is There is a method of calculating and learning a first-order delay time constant γ from the change in the cylinder intake air amount rQa when it changes.

  Further, as a method of setting the delay time Dly and the first-order delay time constant γ by learning, there are two methods depending on the difference between idle and off-idle, the accelerator opening Acc, the actual throttle opening rTH, and the cylinder intake air amount rQa. A method of learning as a set value, a method of learning as a table reference value with the gear position, the engine speed Ne, the actual throttle opening rTH, and the cylinder intake air amount rQa as an axis, and the engine speed Ne and the actual throttle opening rTH And a method of learning as a reference value of a map with the engine speed Ne and the cylinder intake air amount rQa as axes.

  The detailed description of FIG. 1 and the embodiments that can be selected in place of FIG. 1 have been described above. The main point is that the fuel injection phase correction means 406 delays the response of the fuel injection to match the phase of the fuel injection and the phase of the air intake. By the way, particularly when the target throttle opening calculating means 403 calculates the target throttle opening tTH in accordance with the feedback control shown in FIGS. 8 and 21, the response of the air intake is accelerated, the phase of the fuel injection and the air intake There is a method of adjusting the phase.

  Specifically, feedback constant setting means for setting a feedback constant according to the operating state is provided in the target throttle opening feedback calculation means of FIGS. As feedback constant setting means, there is a method of switching the feedback constant to one of two set values according to the difference between idle and off-idle, accelerator opening Acc, actual throttle opening rTH, and cylinder intake air amount rQa. A method for obtaining a feedback constant by referring to a table centered on the accelerator opening Acc, the engine speed Ne, the actual throttle opening rTH, and the cylinder intake air amount rQa, and the engine rotational speed Ne and the actual throttle opening rTH as axes. There is a method of obtaining a feedback constant by referring to a map or a map with the engine speed Ne and the cylinder intake air amount rQa as axes.

  FIG. 27 shows the effect of the feedback constant setting means for setting the feedback constant in the target throttle opening feedback calculation means in accordance with the operating state. As shown in FIG. 27 (a), when there is no feedback constant setting means, the same feedback constant is used in the transient state as in the steady state, so the change in the cylinder intake air amount rQa is slowed, resulting in a change in the air-fuel ratio. When the target air-fuel ratio tAF is switched, the convergence of the actual air-fuel ratio to the target air-fuel ratio tAF is delayed. On the other hand, when there is a feedback constant setting means as shown in FIG. 27 (b), since a larger feedback constant is used during the transient time than during the steady state, the change in the cylinder intake air amount rQa can be accelerated, and the air-fuel ratio can be reduced. It can be controlled constantly. Controlling the air-fuel ratio to a constant leads to suppression of drivability and exhaust deterioration. Further, when the target air-fuel ratio tAF is switched, the convergence of the actual air-fuel ratio to the target air-fuel ratio tAF can be accelerated.

  Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various designs can be made without departing from the spirit of the present invention described in the claims. Can be changed.

The control block diagram which makes one Embodiment of this invention is shown. 1 shows an example of an in-cylinder injection engine system to which the present invention is applied. The block diagram of the control unit to which this invention is applied is shown. The control block diagram of this invention is shown. The control block diagram of an intake air amount calculating means is shown. 6 shows a flowchart of the intake air amount calculation means of FIG. The model figure of an intake pipe is shown. The control block diagram of the target throttle opening calculating means is shown. FIG. 9 is a flowchart of a target throttle opening calculation unit in FIG. 8. FIG. The control block diagram of a fuel-injection phase correction | amendment means is shown. 11 shows a flowchart of the fuel injection phase correction means of FIG. The figure which shows the calculation method of an air response time constant is shown. The figure which shows the effect of the fuel-injection phase correction | amendment means of FIG. The control block diagram of a throttle passage air amount calculating means is shown. The control block diagram of the intake pipe pressure estimation means is shown. The control block diagram of a cylinder intake air amount calculating means is shown. The control block diagram of a target air quantity calculating means is shown. The control block diagram of the target throttle opening calculating means is shown. The control block diagram of the target throttle opening calculating means is shown. FIG. 20 is a flowchart of a target throttle opening calculation unit in FIG. The control block diagram of the target throttle opening calculating means is shown. The flowchart of the target throttle opening calculating means of FIG. 21 is shown. The control block diagram of a fuel-injection phase correction | amendment means is shown. The flowchart of the fuel-injection phase correction | amendment means of FIG. 23 is shown. The control block diagram of a fuel-injection phase correction | amendment means is shown. The figure which shows the effect of the fuel-injection phase correction | amendment means of FIG. The figure which shows the effect of the target throttle opening feedback constant setting means is shown.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 203 ... Air flow sensor, 204 ... Throttle sensor, 207 ... Engine, 208 ... Spark plug, 209 ... Injector, 215 ... Control unit, 224 ... Intake pipe pressure sensor.

Claims (34)

  Reference pulse width calculating means for calculating a reference pulse width that is a reference for calculating the fuel injection pulse width according to the operating state, target air-fuel ratio calculating means for calculating the target air-fuel ratio according to the operating state, A target throttle opening degree calculating means for calculating a target throttle opening degree according to an operating state including the fuel ratio, and a fuel injection phase correcting means for calculating a filtering reference pulse width by applying a temporal filter to the reference pulse width; An engine control apparatus that performs fuel injection control by calculating a fuel injection amount based on a filtering reference pulse width.   2. The engine control device according to claim 1, further comprising intake air amount calculation means for detecting or calculating an actual air amount sucked into a cylinder of the engine and a cylinder intake air amount.   3. The engine according to claim 2, wherein the intake air amount calculation means detects or calculates a throttle passage air amount, and calculates a cylinder intake air amount by applying a temporal filter to the throttle passage air amount. Control device.   3. The intake air amount calculating means according to claim 2, wherein the intake air amount calculating means detects or calculates the throttle passing air amount, and the intake pipe internal pressure for estimating and calculating the intake pipe pressure from the throttle passing air amount and the cylinder intake air amount. An engine control device comprising pressure estimating means and cylinder intake air amount calculating means for calculating a cylinder intake air amount from an engine speed and an intake pipe pressure.   3. The intake air amount calculating means according to claim 2, comprising: an intake pipe pressure detecting means for detecting an intake pipe internal pressure; and a cylinder intake air amount calculating means for calculating a cylinder intake air amount from an engine speed and an intake pipe pressure. An engine control device characterized by that.   6. The engine control device according to claim 1, further comprising target air amount calculation means for calculating a target air amount to be sucked into a cylinder of the engine.   7. The engine control device according to claim 6, wherein the target air amount calculating means calculates a target air amount based on a reference pulse width, a target air-fuel ratio, and an engine speed.   8. The engine control apparatus according to claim 1, wherein the reference pulse width calculation means obtains the reference pulse width with reference to a map with the engine speed and the accelerator opening as axes. .   9. The engine control device according to claim 1, wherein the target air-fuel ratio calculating means obtains the target air-fuel ratio with reference to a map having the engine speed and the reference pulse width as axes. .   10. The fuel injection phase correcting means according to claim 1, wherein the fuel injection phase correcting means is a cylinder intake air amount calculated or detected by an intake air amount calculating means, a previous calculation or detected cylinder intake air amount and a target air. Engine control characterized in that an air response time constant of a cylinder intake air amount is calculated from a target air amount calculated by an amount calculating means, and a filtering reference pulse width is obtained using the air response time constant as a temporal filter. apparatus.   10. The fuel injection phase correcting means according to claim 1, wherein the fuel injection phase correcting means is a coefficient that makes the air-fuel ratio stoichiometric (A / F = 14.7) by dividing the cylinder intake air amount by the engine speed. Multiplying the actual basic pulse width per cylinder and calculating the actual basic pulse width, and multiplying the reference pulse width by the target air-fuel ratio and dividing it by the stoichiometric air-fuel ratio (14.7) is used as the target basic pulse width A target basic pulse width calculation means is provided to calculate the response time constant of the actual basic pulse width from the actual basic pulse width, the actual basic pulse width calculated last time, and the target basic pulse width. An engine control device characterized by obtaining a filtering reference pulse width as a simple filter.   10. The engine control according to claim 1, wherein the fuel injection phase correcting means obtains a filtering reference pulse width by multiplying a reference pulse width by a ratio of a cylinder intake air amount and a target air amount. apparatus.   In claim 12, only when the target air-fuel ratio is within the range of a delay time after switching, and the ratio of the cylinder intake air amount and the target air amount is within a range defined by a certain threshold value. An engine control device characterized in that the reference pulse width is directly used as a filtering reference pulse width.   10. The engine control apparatus according to claim 1, wherein the fuel injection phase correction means obtains a filtering reference pulse width by delaying a reference pulse width by a delay time.   10. The engine control device according to claim 1, wherein the fuel injection phase correction means obtains a filtering reference pulse width from a reference pulse width based on a first-order delay time constant.   16. The delay time or the first-order lag time constant according to claim 14 or 15, depending on a difference between idle and off-idle, an accelerator opening, an actual throttle opening, and a cylinder intake air amount. An engine control device characterized by switching to one of various setting values.   16. The delay time or the first-order lag time constant according to claim 14 or 15 is obtained by referring to a table centered on a gear position, an engine speed, an actual throttle opening, and a cylinder intake air amount. An engine control device characterized by that.   16. The delay time or the first-order lag time constant according to claim 14 or 15, wherein a map centering on an engine speed and an actual throttle opening, an engine speed and a cylinder intake air amount are set. An engine control device characterized in that it is obtained by referring to a map with axes.   15. The engine control device according to claim 14, wherein a time from when the target throttle opening changes until the cylinder intake air amount changes is learned as a delay time.   16. The engine control device according to claim 15, wherein a first-order lag time constant is learned from a change in the cylinder intake air amount when the target throttle opening changes.   21. The delay time or the first-order lag time constant according to claim 19 or 20, depending on a difference between idle and off-idle, accelerator opening, throttle actual opening, and cylinder intake air amount. An engine control device that learns as a set value of a seed.   21. The delay time or the first-order lag time constant is learned as a table reference value based on a gear position, an engine speed, an actual throttle opening, and a cylinder intake air amount. An engine control device characterized by that.   In any one of Claims 19 and 20, the delay time and the time constant of the first-order lag are represented by a map with the engine speed and the throttle actual opening as axes, and the engine speed and the cylinder intake air amount. An engine control device that learns as a reference value of a map with an axis.   24. The target throttle opening calculating means according to claim 1, wherein the target throttle opening calculating means calculates a throttle opening corresponding to a rotational speed feedback correction in accordance with a rotational speed feedback correction for causing the rotational speed during idling to follow the target rotational speed. And a throttle-equivalent throttle opening calculating means for calculating a load-equivalent throttle opening based on corrections for loads such as an air conditioner, power steering, electric load (current consumption), electric radio fan, etc. Accelerator-equivalent throttle opening calculation means for calculating the accelerator-equivalent throttle opening based on the accelerator opening is provided, and the sum of the rotation speed feedback correction equivalent throttle opening, the load equivalent throttle opening, the accelerator equivalent throttle opening, and the target sky The target throttle opening is calculated based on the fuel ratio. The engine control apparatus according to.   24. The target throttle opening calculating means according to claim 1, wherein the target throttle opening calculating means is provided with target air amount calculating means for calculating a target air amount, and the target air opening is converted by throttle opening. What is needed is an engine control device.   In any one of Claims 1 to 23, the target throttle opening calculation means is an intake air amount calculation means for detecting or calculating a cylinder intake air amount, a target air amount calculation means for calculating a target air amount, An engine control apparatus comprising a target throttle opening feedback calculation means for calculating a target throttle opening in accordance with feedback control for causing the cylinder intake air amount to follow the target air amount.   24. The target throttle opening degree calculation means according to claim 1, wherein the target throttle opening degree calculation means is an intake air amount detection means for detecting or calculating a cylinder intake air amount, and the air intake ratio is calculated by dividing the cylinder intake air amount by the engine speed. Is the actual basic pulse width calculation means for calculating the actual basic pulse width per cylinder by multiplying by a coefficient such that A / F = 14.7, and the reference pulse width is multiplied by the target air-fuel ratio to The target throttle opening is calculated in accordance with target basic pulse width calculation means that calculates the target basic pulse width divided by the air-fuel ratio (14.7) and feedback control that causes the actual basic pulse width to follow the target basic pulse width. An engine control device provided with a target throttle opening degree feedback calculation means.   28. The engine control device according to claim 26, further comprising feedback constant setting means for setting a feedback constant of the target throttle opening feedback calculation means in accordance with an operating state.   29. The feedback constant setting means according to claim 28, wherein the feedback constant is switched to one of two set values according to the difference between idle and off-idle, accelerator opening, actual throttle opening, and cylinder intake air amount. An engine control device characterized by that.   29. The engine control apparatus according to claim 28, wherein the feedback constant setting means obtains the feedback constant by referring to a table centered on the accelerator opening, the engine speed, the actual throttle opening, and the cylinder intake air amount. .   29. The feedback constant setting means according to claim 28, wherein the feedback constant is determined by referring to a map with the engine speed and the actual throttle opening as axes and a map with the engine speed and cylinder intake air as axes. An engine control device characterized by that.   32. The engine control device according to claim 1, wherein the actuator for operating the target throttle opening calculated by the target throttle opening calculating means is an electronically controlled throttle.   The engine control device according to any one of claims 1 to 32, wherein an object to be controlled is a lean combustion engine. The engine control device according to any one of claims 1 to 32, wherein an object to be controlled is an in-cylinder injection engine.

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