WO1996021098A1

WO1996021098A1 - Fuel injection control device for an internal combustion engine

Info

Publication number: WO1996021098A1
Application number: PCT/JP1995/002765
Authority: WO
Inventors: Hidetaka Maki; Shusuke Akazaki; Yusuke Hasegawa; Yoichi Nishimura
Original assignee: Honda Giken Kogyo Kabushiki Kaisha
Priority date: 1994-12-30
Filing date: 1995-12-28
Publication date: 1996-07-11
Also published as: KR100407298B1; CN1065586C; KR970701302A; TW312732B; CN1143402A

Abstract

In a case where a feedback correction coefficient is suitably calculated using a control algorithm having an adaptative parameter regulating mechanism employing the Landau's regulation law, even when the parameter regulating mechanism is operated for each fuel control cycle for each TDC, an input used in the parameter regulating mechanism should be a value for each combustion cycle such as TDC in a specific cylinder. In addition, an adaptative controller and the parameter regulating mechanism for calculating an adaptative parameter used in the adaptative controller are operated in synchronism with a combustion cycle, and the control cycle of the adaptative controller and the parameter regulating mechanism is changed in accordance with the number of revolutions of the engine. This makes it possible to reduce a matrix operation volume so as to reduce in turn the load of an on-vehicle computer, thereby making it possible not only to complete an operation within one TDC but also to improve the controllability by reducing idle time. Thus, it is possible to continue the adaptative control even in a driving situation such as at a high revolution when the operation time tends to be reduced, thereby making it possible to obtain a good controllability.

Description

Specification

Fuel injection control device for internal combustion engine

Technical field

The present invention relates to a fuel injection control device for an internal combustion engine, and more specifically to a fuel injection control device that performs fuel injection control using adaptive control and can be realized on an actual machine. Background art

Recently, adaptive control theory has also been introduced for internal combustion engines, and technology is used to control the amount of fuel actually drawn into cylinders using the optimal regulation system, which is one of modern control theories, so that the amount of fuel actually matches the target amount of fuel. Japanese Patent Application Laid-Open No. H11-110,

The technology of 85.3 can be mentioned.

The present applicant has also proposed a fuel injection control for an internal combustion engine using adaptive control in Japanese Patent Application No. 6-666, 594 or the like. By the way, when a fuel injection control device using the above-described adaptive control is mounted on an internal combustion engine, the operation time of the internal combustion engine increases and decreases due to fluctuations in the engine speed, and the microcomputer mounted on the internal combustion engine is also free from performance constraints. is not. The normal fuel control cycle is every TDC, but it takes about 8 to 12 TDC from the injection of fuel to the detection of the control result.

There is a dead time of 12 control cycles. When the dead time of the controlled object is large, the controllability generally deteriorates compared to when the dead time is small. This is particularly remarkable in adaptive control.

Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a fuel injection control device for an internal combustion engine した in which an adaptive controller can be actually used in an actual machine while ensuring controllability. Oh.

Furthermore, in an internal combustion engine fuel injection control device that determines an operation amount using an adaptive control law, adaptive control is continuously performed even in a running state in which the calculation time is reduced, such as at a high speed. It is an object of the present invention to provide a fuel injection control device for an internal combustion engine that achieves good controllability. Disclosure of the invention In order to achieve the above object, according to the present invention, there is provided a fuel injection amount control means for controlling a fuel injection amount of a multi-cylinder internal combustion engine, wherein the fuel injection amount is adaptively matched with a target value as an operation amount. An adaptive controller that causes the adaptive controller to calculate an adaptive parameter used by the adaptive controller; and an adaptive parameter adjusting mechanism that calculates an adaptive parameter used by the adaptive controller. The input is performed in synchronization with the fuel control cycle of the internal combustion engine, and the adaptive parameter adjustment mechanism adjusts the adaptive parameter according to at least one of the air-fuel ratio and the in-cylinder fuel amount based on a specific combustion cycle. Is configured to perform the calculation of

Further, the input to the adaptive parameter adjustment mechanism is configured to be performed in synchronization with a fuel control cycle of a specific cylinder of the internal combustion engine.

Further, the adaptive controller is configured to operate in synchronization with a fuel control cycle of the internal combustion engine.

Furthermore, air-fuel ratio detection means for detecting the exhaust air-fuel ratio of the internal combustion engine, fuel injection quantity control means for controlling the fuel injection amount of the internal combustion engine for each fuel control cycle, and at least the detected exhaust air-fuel ratio based on the detected exhaust air-fuel ratio A controller of a recurrence type in which a controller of a recurrence type is used as a manipulated variable to use a controller of a recurrence type, and a fuel injection control device for an internal combustion engine, comprising: The controller of the formula type is configured to operate in synchronization with a period longer than the fuel control cycle in a predetermined operation state. Further, the controller of the recurrence type is configured to be an adaptive controller.

Further, the adaptive controller includes an adaptive parameter-evening adjusting mechanism for calculating an adaptive parameter used in the adaptive controller, and at least the detected exhaust air-fuel ratio is input to the adaptive parameter adjusting mechanism, and the adaptive parameter is adjusted. The evening adjustment mechanism is configured to operate in synchronization with a longer cycle than the fuel control cycle in a predetermined operation state. Further, the cycle longer than the fuel control cycle is configured to have a value corresponding to an integral multiple of the combustion cycle.

Further, the detected air-fuel ratio input to the controller of the recurrence type is configured to be a value based on a plurality of values detected in a cycle shorter than the operation cycle of the controller of the recurrence type. .

Further, the detected air-fuel ratio input by the adaptive parameter adjusting mechanism is The value is configured to be based on a plurality of values detected in a cycle shorter than the operation cycle of the meter adjustment mechanism.

Further, the fuel injection amount control means for controlling the fuel injection amount of the internal combustion engine, an adaptive controller that operates so that the fuel injection amount is equal to a target value as an operation amount, and an adaptive parameter used in the adaptive controller. A fuel injection control device for a fuel-burning engine, comprising: an adaptive parameter adjusting mechanism for calculating; and an operating state detecting means for detecting an operating state of the internal combustion engine; and the adaptive controller according to the detected operating state. In addition, the control period of at least one of the adaptive parameter adjustment mechanisms is changed.

Furthermore, the control cycle of the adaptive parameter adjusting mechanism is configured to be equal to or longer than the control cycle of the adaptive controller.

Furthermore, the control cycle of the adaptive parameter adjustment mechanism is configured to be an integral multiple of the control cycle of the adaptive controller.

Further, the control cycle of at least one of the adaptive controller and the adaptive parameter adjustment mechanism is changed at a cycle that is an integral multiple of the fuel control cycle.

Furthermore, the operating state is configured to be at least the engine speed. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram generally showing a fuel injection amount control device for an internal combustion engine according to the present application.

FIG. 2 is an explanatory diagram showing details of an exhaust gas recirculation mechanism in FIG.

FIG. 3 is an explanatory diagram showing details of a canister-purging mechanism in FIG. FIG. 4 is an explanatory diagram showing valve timing characteristics of the variable valve timing mechanism in FIG.

FIG. 5 is a block diagram showing details of the control unit in FIG.

FIG. 6 is a main flow chart showing the operation of the fuel injection control device for an internal combustion engine according to the present application.

FIG. 7 is a block diagram functionally showing the operation of the flowchart shown in FIG. FIG. 8 is a timing chart showing an example of the operation of the adaptive controller used in the fuel injection control device for the internal combustion engine according to the present application. FIG. 9 is a timing chart showing another example of the operation of the adaptive controller used in the fuel injection control device for an internal combustion engine according to the present application.

FIG. 10 is a block diagram in which the configuration of the block diagram of FIG. 6 is rewritten focusing on the STR controller and the adaptive parameter adjustment mechanism.

FIG. 11 is a flowchart of FIG. 6 showing a subroutine “flow” showing the operation of calculating an average value such as a feedback correction coefficient based on the adaptive control law of the chart. FIG. 12 is a timing chart for explaining the operation of calculating the flowchart of FIG.

FIG. 13 is a subroutine 'flow' chart for explaining the instability determination of the adaptive control system in the flow chart of FIG.

FIG. 14 is an explanatory diagram illustrating the flow of FIG. 13 and the determination of the instability of the chart.

FIG. 15 is an explanatory diagram similar to FIG. 14 for explaining the work of determining the instability of the flow chart of FIG.

FIG. 16 is a timing chart showing another example of the operation of the adaptive controller similar to FIG.

FIG. 17 is a timing chart showing another example of the operation of the adaptive controller similar to FIG.

FIG. 18 is a flow chart showing a second embodiment of the apparatus according to the present application.

FIG. 19 is an explanatory diagram showing the characteristics of the map used in the FIG. 18 flow chart.

FIG. 20 is an explanatory diagram showing characteristics of a table used in the flowchart of FIG.

FIG. 21 is an explanatory diagram showing the characteristics of a table similar to FIG. 20 used in the flowchart of FIG. 18.

FIG. 22 is an explanatory diagram showing the characteristics of the same table as FIG. 20 used in the flow and chart of FIG.

Fig. 23 shows a table similar to Fig. 20 used in Fig. 18 flow chart. FIG. 4 is an explanatory diagram showing characteristics of the present invention.

FIG. 24 is a flow chart showing a third embodiment of the apparatus according to the present application.

FIG. 25 is a flowchart showing a fourth embodiment of the apparatus according to the present application.

FIG. 26 is an explanatory diagram showing the characteristics of the dead zone used in the flowchart of FIG. 25.

FIG. 27 is a flowchart showing a fifth embodiment of the apparatus according to the present application.

FIG. 28 is an explanatory diagram showing characteristics of the limit used in the flow chart of FIG. 27.

FIG. 29 is a flow chart showing a sixth embodiment of the apparatus according to the present application.

FIG. 30 is an explanatory diagram showing the characteristics of the map used in the flowchart of FIG. 29.

FIG. 31 is a flow chart showing a seventh embodiment of the apparatus according to the present application.

FIG. 32 is an explanatory diagram for explaining the work of the flowchart of FIG. 31.

FIG. 33 is a flow chart showing an eighth embodiment of the apparatus according to the present application.

FIG. 34 is a flow chart showing a ninth embodiment of the apparatus according to the present application.

FIG. 35 is a flowchart showing a tenth embodiment of the apparatus according to the present application.

FIG. 36 is a block diagram for explaining the operation of the flowchart of FIG. 35. FIG. 37 is an explanatory diagram showing the relationship between the TDC of a multi-cylinder internal combustion engine and the air-fuel ratio of the exhaust system assembly.

FIG. 38 is an explanatory diagram showing the quality of the sample timing with respect to the actual air-fuel ratio. FIG. 39 is a flowchart showing a sampling operation of the air-fuel ratio in the Sel-V block in the block diagram of FIG.

FIG. 40 is a block diagram showing an example in which the detection operation of the air-fuel ratio sensor described in the earlier application is modeled as one of explanatory diagrams of the observer in the block diagram of FIG.

FIG. 41 is a model obtained by dispersing the model shown in FIG. FIG. 42 is a block diagram showing a true air-fuel ratio estimator modeling the detection behavior of the air-fuel ratio sensor.

FIG. 43 is a block diagram showing a model showing the behavior of the exhaust system of the internal combustion engine.

4 4 figure 4 3 1 the air-fuel ratio of the three cylinders for four-cylinder internal combustion engine with the model shown in FIG. 4 7:. 1, 1 air-fuel ratio of one cylinder 2 _0:. In the first fuel FIG. 6 is a data diagram showing a case in which is supplied.

FIG. 45 is a data diagram showing the air-fuel ratio of the collective part of the model in FIG. 43 when the input shown in FIG. 44 is given.

Figure 46 shows the air-fuel ratio of the collective part of the model in Fig. 43 when the input shown in Fig. 44 is given, taking into account the response delay of the LAF sensor, and the LAF sensor for the same case. It is a graph which compares the actual measurement value of an output.

FIG. 47 is a block diagram showing a configuration of a general observer.

FIG. 48 is a block diagram showing the structure of the observer used in the earlier application, which is the observer shown in the block diagram of FIG.

FIG. 49 is an explanatory block diagram showing a configuration in which the model shown in FIG. 43 and the observer shown in FIG. 48 are combined.

FIG. 50 is a block diagram showing feedback control of the air-fuel ratio in the block diagram of FIG.

FIG. 51 is an explanatory diagram showing characteristics of a timing map used in the flowchart of FIG.

FIG. 52 is an explanatory diagram for explaining the characteristics of FIG. 51 and showing sensor output characteristics with respect to engine speed and engine load.

FIG. 53 is a flow chart of FIG. Mining chart.

FIG. 54 is a flowchart showing an eleventh embodiment of the apparatus according to the present application.

FIG. 55 is a block diagram for explaining the operation of the flowchart of FIG. 54. FIG. 56 is a flow chart of FIG. 54, which is a subroutine flow chart showing the work of determining the instability of the adaptive control system of the chart.

FIG. 57 is a timing chart for explaining the dead time in the calculation of the fuel injection amount of the internal combustion engine. BEST MODE FOR CARRYING OUT THE INVENTION

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

FIG. 1 is an overall view schematically showing a fuel injection control device for an internal combustion engine according to the present application.

In the figure, reference numeral 10 denotes an OHC in-line four-cylinder internal combustion engine, and the flow rate of intake air introduced from an air cleaner 14 disposed at the end of an intake pipe 12 is adjusted by a throttle valve 16. Meanwhile, the gas flows into the first to fourth cylinders via the surge tank 18 and the intake manifold 20 via two intake valves (not shown). An injector 22 is provided near an intake valve (not shown) of each cylinder to inject fuel. The air-fuel mixture injected and integrated with the intake air is ignited in each cylinder by an ignition plug (not shown) in the order of the first, third, fourth, and second cylinders, burns, and is burned by a piston (not shown). Is driven.

'' After combustion, the exhaust gas is discharged to the exhaust manifold 24 through two exhaust valves (not shown), is purified through the exhaust pipe 26, and is purified by the catalyst device (three-way catalyst) 28, and is discharged outside the engine. It is exhausted. As described above, the throttle valve 16 is mechanically disconnected from the accelerator pedal (not shown), and is controlled via the pulse motor M to an opening corresponding to the depression amount of the accelerator pedal and the operating state. In addition, a bypass passage 32 is provided in the intake pipe 12 near the position where the throttle valve 16 is disposed, to bypass the throttle valve 16.

Here, the internal combustion engine 100 is provided with an exhaust gas recirculation mechanism 100 for recirculating exhaust gas to the intake side. Explaining with reference to FIG. 2, the exhaust gas recirculation path 12 1 of the exhaust gas recirculation mechanism 100 has a first catalyst device 28 (FIG. The other end 12 lb communicates with the downstream side of the throttle valve 16 (not shown in FIG. 2) of the intake pipe 12 on the upstream side of (omitted). An exhaust gas recirculation valve (recirculation gas control valve) 122 for adjusting the amount of exhaust gas recirculated and a volume chamber 121c are provided in the middle of the exhaust gas recirculation path 121. The exhaust air flow valve 122 is a solenoid valve having a solenoid 122 a. The solenoid 122 a is connected to a control unit (ECU) 34 described later, and is controlled by an output from the control unit 34. The valve opening is changed linearly. The exhaust gas recirculation valve 122 is provided with a lift sensor 123 for detecting the valve opening, and the output is sent to the control unit 34.

Furthermore, a connection between the intake system of the internal combustion engine 10 and the fuel tank 36 is provided, and a canister / purge mechanism 200 is provided.

As shown in FIG. 3, the purge mechanism 200 is provided between the upper part of the sealed fuel tank 36 and the downstream side of the throttle valve 16 of the intake pipe 12, as shown in FIG. It consists of a passage 2 21, a canister 2 3 containing a sorbent 2 3 1, and a purge passage 2 2 4. A two-way valve 222 is installed in the middle of the steam supply passage 221.A purge control valve 225 and a mixture of fuel gas containing fuel vapor flowing through the purge passage 224 are provided in the middle of the purge passage 224. A flow meter 222 for detecting the flow rate and an HC concentration sensor 227 for detecting the HC concentration in the air-fuel mixture are provided. The purge control valve (electromagnetic valve) 222 is connected to the control unit 34 as described later, and is controlled in accordance with a signal from the control unit 34 to linearly change the valve opening amount.

According to this purging mechanism, when the fuel vapor (fuel vapor) generated in the fuel tank 36 reaches a predetermined set amount, the positive pressure valve of the 2-way valve 222 is opened and opened. It flows into 223 and is adsorbed and stored by the adsorbent 231. When the purge control valve 225 is opened by the valve opening amount corresponding to the duty ratio of the on / off control signal from the control unit 34, the evaporated fuel temporarily stored in the canister 220 is discharged to the suction pipe. Due to the negative pressure in 12, the air is sucked into the intake pipe 12 through the purge control valve 2 25 together with the outside air sucked from the outside air intake port 2 32 and sent to each cylinder. When the fuel tank 36 is cooled by the outside air and the negative pressure in the fuel tank increases, 2 ゥ The negative pressure valve of the A-valve 222 is opened, and the fuel vapor temporarily stored in the canister 222 is returned to the fuel tank 36.

Further, the internal combustion engine 10 includes a so-called variable valve timing mechanism 300 (shown as V / T in FIG. 1). The variable valve timing mechanism 300 is described in, for example, Japanese Patent Application Laid-Open No. 2-275,043. The valve timing V of the engine is controlled according to the operating state such as the engine speed Ne and the intake E force P. / T is switched between oV / T and HiV / T with the two types of timing characteristics shown in Fig. 4. However, since the mechanism itself is a known mechanism, the description is omitted. The switching of the valve timing characteristics includes an operation of stopping one of the two intake valves.

In FIG. 1, a crank angle sensor 40 for detecting a crank angle position of a piston (not shown) is provided in a distribution box (not shown) of the internal combustion engine 10, and a throttle valve 16 for the throttle valve 16 is provided. A throttle opening sensor 42 for detecting the opening degree and an absolute pressure sensor 4 for detecting the intake pressure Pb downstream of the throttle valve 16 as an absolute pressure are also provided. An atmospheric pressure sensor 46 for detecting the atmospheric pressure Pa is provided at an appropriate position of the internal combustion engine 10, and an intake air temperature sensor 48 for detecting the temperature of the intake air is provided upstream of the throttle valve 16. In addition, a water temperature sensor 50 for detecting an engine cooling water temperature is provided at an appropriate position of the engine. Further, a valve timing (V / T) sensor 52 (not shown in FIG. 1) for detecting a valve timing characteristic selected by the variable valve timing mechanism 300 via hydraulic pressure is also provided. Further, in the exhaust system, a wide area air-fuel ratio sensor 54 is provided in an exhaust system gathering section downstream of the exhaust manifold 24 and upstream of the catalyst device 28. These sensor outputs are sent to the control unit 34.

FIG. 5 is a block diagram showing details of the control unit 34. The output of the wide-range air-fuel ratio sensor 54 is input to the detection circuit 62, where appropriate di-type processing is performed, and a linear proportional to the oxygen concentration in the exhaust gas in a wide range from lean to rich. It outputs a detection signal with various characteristics (hereinafter, this wide-range air-fuel ratio sensor is called “LAF sensor”).

The output of the detection circuit 62 is input into the CPU via the multiplexer 66 and the AZD conversion circuit 68. The CPU includes a CPU core 70, a ROM 72, and a RAM 74. The output of the detection circuit 62 is more specifically described as having a predetermined crank angle (for example, 15 degrees). ) Is converted to AZD every time and sequentially stored in one of the buffers in the RAM 74. The 12 buffers are numbered 0 to 11 later, as shown in Figure 53. Analog sensor outputs from the throttle opening sensor 42 and the like are also taken into the CPU via the multiplexer 66 and the AZD conversion circuit 68, and stored in the RAM 74.

After the output of the crank angle sensor 40 is shaped by the waveform shaping circuit 76, the output value is counted by the power counter 78, and the count value is input into the CPU. In the CPU, the CPU core 70 calculates a control value according to the order stored in the ROM 72 as described later, and drives the injector 22 of each cylinder via the drive circuit 82. Further, the CPU core 70 is provided with a magnetic valve 90 (opening / closing of a bypass passage 32 for adjusting the amount of secondary air) through drive circuits 84, 86, 88, and the above-mentioned electromagnetic valve for controlling exhaust gas recirculation. 1 2 2 and canister ・ Purge control solenoid valve 225 is driven. In FIG. 5, the illustration of the lift sensor 123, the flow meter 226, and the HC concentration sensor 227 is omitted.

-FIG. 6 is a flow chart showing the operation of the control device according to the present application.

First, the engine speed Ne and the intake pressure Pb detected in S10 are read out, and the process proceeds to S12 to determine whether or not cranking is performed. Judge whether it is force. The fuel cut is performed when the fuel supply is stopped, the fuel supply is stopped, and the fuel injection is performed when the throttle valve is in the fully closed position and the engine speed is equal to or higher than a predetermined value. Is controlled in an open loop.

If it is determined in S14 that the fuel cut is not a fuel cut, the process proceeds to S16, in which a map is searched from the detected engine speed Ne and the intake pressure Pb to calculate a basic fuel fuel injection amount Tim. . Then, the process proceeds to S18, where it is determined whether the activation of the LAF sensor 54 is completed. This is performed, for example, by comparing the difference between the output power E of the LAF sensor 54 and its central power E with a predetermined value (for example, 0.4 V), and determining that activation has been completed when the difference is smaller than the predetermined value. . When it is determined that the activation has been completed, the process proceeds to S20, and it is determined whether or not the activation is in the feedback control area. If the operating state changes due to high rotation, full throttle, or high water temperature, the injection amount is controlled by open lube. You. When it is determined that the feedback control area is determined in S20, the process proceeds to S22, where the LAF sensor detection value is read, and the process proceeds to S24, where the detected air-fuel ratio KACT (k) (k: sampling time. The same applies hereinafter. ). Then, the process proceeds to S26, in which the feedback correction coefficient K according to the PID control law is calculated to calculate AF (k).

The feedback correction coefficient KLAF based on the PID control law is calculated as follows.

First, the control deviation DKAF between the target air-fuel ratio KCMD and the detected air-fuel ratio KACT

DKAF (k) = KCMD (k-d ') -KACT (k)

And ask. In the above, KCMD (kd '): target air-fuel ratio (where d' indicates the dead time until KCMD is reflected in KACT, and thus means the target air-fuel ratio before the dead time control cycle), KACT (k: Indicates the detected air-fuel ratio (for the current control cycle) In this specification, the air-fuel ratio is actually expressed as the equivalence ratio, ie, MstZM = 1, for both the target value KCMD and the detected value KACT (Mst: theoretical air-fuel ratio, Mst = AZF (A: Air consumption, F: Fuel consumption, S: Excess air ratio)).

Then, multiply it by a given coefficient to get the P-term KLAFP (k), I-term KLAFI (k), and D-term KFD (k).

P term: KLAFP (k) = DKAFOO xKP

Term I: KLAF I (k) = KLAF I (k-1) + DKAF (k) x KI

Term D: KLAFD (k) = (DKAFOO -DKAF (k-l)) xKD

And ask.

Thus, the P term is obtained by multiplying the deviation by the proportional gain KP, and the I term is obtained by adding the value obtained by multiplying the deviation by the edge gain KI to the previous value KLAFl (kl) of the feedback correction coefficient, The D term is obtained by multiplying the difference between the current value DKAFO of deviation and the previous value DKAF (kl) by the derivative gain KD. Note that each gain KP.KI.KD is determined according to the engine speed and the engine load, and more specifically, is set so that it can be searched from the engine speed Ne and the intake pressure Pb using a map. Keep it. Finally, the value obtained by

KLAF (k) = KLAFP (k) + KLAF I (k) + KLAFD (k)

And the current value KLAF (k) of the feedback correction coefficient based on the PID control law. In this case, the offset is set because the feedback correction coefficient is obtained by multiplication correction. It is assumed that the value of 1.0 is included in the I term KLAFi (k) (that is, the initial value of KLAFKk) is 1.0.

Fig. 6 Flow * In the chart, the process proceeds to S28, where the feedback correction coefficient KSTR (k) based on the adaptive control law is calculated. The feedback correction coefficient KSTR (k) based on this adaptive control law will be described later in detail.

Then, the process proceeds to S30, in which the obtained basic fuel injection amount T im is multiplied by a target air-fuel ratio correction coefficient KCMDM (k) and another correction coefficient KTOTAL (the product of various correction coefficients performed by multiplication such as water temperature correction). Then, the required fuel injection amount T cyl (k) required by the internal combustion engine is determined. In this control, as described above, the target air-fuel ratio is actually indicated by the equivalent ratio, and is used as a correction coefficient for the fuel injection amount. Since the charging efficiency of the intake air differs due to the heat of vaporization, the target air-fuel ratio is corrected for charging efficiency with appropriate characteristics to obtain the target air-fuel ratio correction coefficient KCMDM.

Then, the program proceeds to S32, in which the required fuel injection amount Tcyl (k) is multiplied by one of the feedback correction coefficient KLAF (k) or KSTR (k) obtained in S26 or S28, and The output fuel injection amount T out (k) is determined by adding the addition term TT0TAL to the product of. Here, the addition term TT0TAL indicates the total value of the correction coefficient performed by the added value such as the atmospheric pressure correction. (However, the invalid time of the indicator is added separately when the output fuel injection amount T out is output. Not included).

Then, proceeding to S34, the output fuel injection amount is determined using the adhesion coefficient obtained by searching the adhesion coefficient map from the engine cooling water temperature, etc. for the determined output fuel injection amount out (k), and the output fuel injection amount is calculated. Perform Tout (k) on the suction pipe wall adhesion correction (the value after adhesion correction is Tout-F (k)). Note that the correction of the suction pipe wall surface adhesion itself has no direct relation to the gist of the present invention, and a description thereof will be omitted. Next, the routine proceeds to S36, in which the output fuel injection amount T out-F (k) corrected for adhesion is output, and the processing ends.

If the result in S18 or S20 is negative, the program proceeds to S38, in which the basic fuel injection amount Tim (k) is multiplied by the target air-fuel ratio correction coefficient KCMDM (k) and various correction coefficients KTOTAL, and The output fuel injection amount T out is calculated by adding the correction addition term TT0TAL to the product of, and the process proceeds to S34. When cranking is determined in S12, the process proceeds to S40 to search for the fuel injection amount Tier during cranking, and proceeds to S42 to output the fuel injection amount according to the start mode equation. The power fuel injection amount Tout is calculated, and if it is determined in S14 that the fuel cut has occurred, the process proceeds to S44 where the output fuel injection amount Tout (k) is set to zero.

Next, the calculation of the feedback correction coefficient KSTR (k) using the adaptive control law mentioned in S28 of the flowchart of FIG. 6 will be described.

FIG. 7 is a block diagram showing the operation more functionally.

The illustrated device is based on the adaptive control technology previously proposed by the present applicant. The STR controller consists of an adaptive controller consisting of an STR (Self-Tuning Regulatory Overnight) controller and an adaptive (control) parameter overnight adjustment mechanism that adjusts its adaptation (control) parameters (vector). Inputs the target value and control amount (plant output) of the feedback system for fuel injection amount control, receives the coefficient vector specified by the adaptive parameter adjustment mechanism, and calculates the output.

In such adaptive control, one of the adjustment rules (mechanisms) of adaptive control is the parameter adjustment rule proposed by ID Landau et al. This method converts the adaptive control system into an equivalent feedback system consisting of a linear block and a non-linear block, so that for nonlinear blocks, Popov's integral inequality for input and output is satisfied, and the di-block is strongly positive. This is a method that guarantees the stability of the adaptive control system by determining the adjustment rule. In other words, in the parameter adjustment rule proposed by Landau et al., The adjustment rule (adaptive rule) expressed in a recurrence formula is obtained by using at least one of the above-mentioned Popov's superstability theory or Lyapunov's direct method. It guarantees its stability.

This technique is for example! "Combitrol j (Corona) No. 27, pages 28-41, or" Automatic Control Handbook "(Ohm) pages 73-707, A Survey of Model Reference Adaptive Techniques- Theory and Application "ID LANDAU" Automaticaj Vol. 10, pp. 353-379, 1974, "Unification of Discrete Time Explicit Model Reference Adaptive Control Designs" ID LANDAU et al. "Automatica" Vol. 17, No. 4, pp. 593- 611, 1981, and "Combining Model Reference Adaptive Controllers and Stochastic Self-tuning Regulators" ID LANDAU "Automaticaj Vol. 18. No. 1, pp. 77-84. I have. In the adaptive control technique shown in the figure, the adjustment law of Landau et al. Was used. Explaining, in Landau et al tuning rules, transfer of the control target of the discrete system閟数8 - ¹⁾ / eight - ') when placed polynomials of the denominator molecules as equations 1 and 2, the parameter adjusting mechanism The adaptive parameter that is identified by 0 is the hat 0 (the same as? (K); the same applies to the following) and is expressed as a vector (transposed vector) as shown in Equation 3. The input ^ (k) to the parameter adjustment mechanism is defined as in Equation 4. Here, when m = 1, n = 1, d = 3, that is, for a blunt having a dead time of three control cycles in the primary system, _t

A (z-') = l + a, z-1. + a „z" number 1 B (z- ¹ ) = bo + bjz " ¹ b _m z number 2

¾ ^T (k) = [bo (k). BR (Z- ', k), SCz " ¹ , k)]

= [bo (k), r, (k),, ₊ d- i (k). So (k). .s _n- , (k) 3

= [bo (k). r! (k), r ₂ (k). r ₃ (k), s. (K)] number 3 T (k) = [u (k)., U (km-d + l), y (k),, y (k-n + l)]

= [u (k). u (k-1), u (k-2). u (k-3). y (k)] Equation 4 where the adaptive parameter shown in Equation 3 is 6> Is a scalar quantity bO hat (k) that determines the gain, a control element BR hat (Zk) expressed using the manipulated variable, and a control element S (Zk) expressed using the control variable. And are represented as Equations 5 to 7, respectively. bo — k) = 1 / b number 5 BR (Z k) = z ^_1 + r ₂ zd-I)

-2 + + l- 1 Z

-3

Z + Γ ₂ Z— ² + Γ3 Z number 6

S (Z ^_I , k) = So + Sj z ^_1 +-· + s „-, z- ^(n-

= s. Equation 7 The parameter adjustment mechanism identifies and estimates the scalar amount and each coefficient of the control element, and sends them to the STR controller as the adaptive parameters shown in Equation 3 above. The parameter adjustment mechanism uses the manipulated variable u (i) of the brand and the controlled variable y (j) (i and j include past values) so that the deviation between the target value and the controlled variable becomes zero. Calculate the overnight hat. The adaptive parameter 0 hat is specifically calculated as shown in Equation 8. In Equation 8, Γ0 is the identification of the adaptive parameter. The gain matrix (m + n + d order) that determines the estimated speed, and the asterisk (k) is the signal indicating the identification and estimation error, as shown in Equations 9 and 10, respectively. It is expressed by a simple recurrence formula.

0 (k)

(k)

1 A ₂ (k) r (k-1) Γ (kd) r ^T (kd) r (kl) r (k) = r (kl) -λ, (k) A, (k) + A ₂ ( k) r ^T (kd) r (kl) ζ (kd)

· · · Number 9

e * (k) = ··· Equation 1 0 l + ^T (kd) r (kl) r (kd) Depending on the choice of λ 1 (k) and λ 2 (k) in Equation 9, various specific Algorithm is given. For example, if λ 1 (k) = 1, A 2 (k) = λ (0 <λ <2), then the gradual gain algorithm (least square method if λ = 1), λ 10 = λ 1 (0 1 1 く 1), λ 2 (Ι = λ 2 (0 2 2 く λ), variable gain algorithm (weighted least squares method when λ 2 = 1), λ 1 (k) / λ If 2 (k) = σ and S 3 is expressed as in Equation 11, then λ 1 (k) = S 3 will result in a fixed trace algorithm, and S 10 = 1, λ 2 ( A fixed gain algorithm is obtained when k) = 0. In this case, as is clear from Equation 9, Γ0Ο = r (kl), and thus a fixed value of Γ0 = 。. Any of the decreasing gain algorithm, the variable gain algorithm, the fixed gain algorithm, and the fixed trace algorithm are suitable for the plant.

A ₃ (k) = l ···· Equation 1 1 σ + ^T (kd) r (k-Dr (kd) ti (O) Here, in FIG. 7, the above-mentioned STR controller (adaptive control) The air-fuel ratio and the adaptive parameter adjustment mechanism are outside the fuel injection amount calculation system, and the detected air-fuel ratio KACT (k) is the target air-fuel ratio KCMD (kd ') (where d' is the KCMD It operates so that it adaptively matches the dead time before it is reflected in KACT) and calculates the feedback correction coefficient KSTR (k). Receiving the coefficient vector 0 (k), which has been uniquely identified, forms a feedback complementer to match the target air-fuel ratio KCMD (k -d *) Computed feedback correction coefficient KSTR (k ) Is multiplied by the required fuel injection amount Tcyl (k), and the corrected fuel The injection amount is supplied as an output fuel injection amount Tout (k) to the control brand (the internal combustion engine) via the adhesion correction compensator.

In this way, the feedback correction coefficient KSTR (k) and the detected air-fuel ratio KACT (k) are obtained and input to the adaptive parameter adjustment mechanism, where the adaptive parameter 0 hat (k) is calculated and input to the STR controller. You. The target air-fuel ratio KCMD (k) is given as an input to the STR controller, and the feedback correction coefficient KSTR (k) is calculated using the recurrence formula so that the detected air-fuel ratio KACT0 matches the target air-fuel ratio KCMDOt -d ') You

^> ο

Specifically, the feedback correction coefficient KSTR (k) is obtained as shown in equation (12) .o STR (k) =

KCMD (kd ')-s. xy (k)-r, xKSTR (kl)-r ₂ xKSTR (k-2)-r ₃ xKSTR (k-3) bo

On the other hand, the detected air-fuel ratio KACT (k) and the target air-fuel ratio KCMD (k) are calculated by the controller (PID control law) described earlier in S26 of the flowchart in Fig. 6. PID is shown in the figure), and the second feedback correction coefficient KLAF (k) is calculated based on the PID control law in order to eliminate the deviation between the detected air-fuel ratio in the exhaust system collecting section and the target air-fuel ratio. . Either the feedback correction coefficient KSTR based on the adaptive control rule or the feedback correction coefficient KLAF based on the PID control law is used for calculating the fuel injection amount via the switching mechanism 400 in FIG. Then, when the operation of the adaptive control system (STR controller) is determined to be unstable, as described later, or when the adaptive control system is out of the adaptive range, the feedback correction coefficient KSTR (k) based on the adaptive control law is used instead. The feedback correction coefficient KLAF (k) based on the PID control law is used.

By the way, when controlling the fuel injection amount of the internal combustion engine, as shown in FIG. It calculates the amount of radiation, and it takes some time for the calculated fuel to be compressed, exploded, and exhausted in the cylinder. Furthermore, considering the time required for the exhaust gas to reach the LAF sensor, the detection delay of the sensor itself, and the time required to calculate the amount of fuel actually sucked into the cylinder from the detected value, this time is further increased. growing. As described above, dead time is inevitably involved in controlling the fuel injection amount of the internal combustion engine. Assuming that the dead time is, for example, three times in the combustion cycle as described above by focusing on one cylinder, the TDC number becomes 12 TDC as shown in FIG. 8 when the internal combustion engine is four cylinders. Here, the “combustion cycle” is a four-stroke process consisting of suction, compression, explosion, and exhaust. In this embodiment, it corresponds to 4 TDC.

In the above adaptive controller (STR controller), the number of elements of the adaptive parameter Θhat (k) is m + n10d, as is apparent from Equation 3, and is proportional to the dead time d. Assuming that the dead time is 3 as in the previous example, when the STR controller and the adaptive parameter adjustment mechanism are operated in synchronization with TDC in order to cope with the ever-changing operation state, the adaptive parameter 0 h (k) Even if the number of elements is m = n = 1, as shown in FIG. 8, d = 1 2 (3 combustion cycles X 4 TDC), and m + n + d = 1. As a result, the calculation of the gain matrix となり becomes a 14 × 14 matrix operation, and the load on the on-board computer increases as the amount of calculation increases, and the performance of a normal on-board computer increases as the engine speed increases. It is difficult to complete the operation within one TDC, and at the same time, as described above, an increase in the number of dead times leads to a deterioration in controllability.

In view of this, the fuel injection control device for an internal combustion engine shown in the figure can cope with ever-changing operating conditions as much as possible, and reduces the amount of matrix calculations to reduce the load on the on-board computer. Specifically, as shown in Fig. 9, the parameter adjustment mechanism is controlled in synchronization with the combustion cycle, and more specifically, only with a specified crank angle (TDC, etc.) of a specific cylinder (such as the first cylinder). The plant output is input, and the above-mentioned adaptive parameter 6-hour hat is calculated.

Here, the calculation of the adaptive parameter 0 hat is performed at a predetermined crank angle (such as TDC) of all cylinders, as is apparent from FIG. Note that the fact that the STR controller operates in synchronization with a predetermined crank angle (such as TDC) of all cylinders to calculate the feedback correction coefficient is not different from the configuration shown in FIG. Thus, for example, when the combustion cycle (fuel control cycle), that is, the operation is performed in synchronization with only a predetermined crank angle of a specific cylinder, d = 3, and the number of elements in the adaptive parameter 0 hat is m + n + d = 5, and the calculation of the gain matrix 減少 is reduced from 14 x 14 to 5 x 5 matrix operation, and the load on the in-vehicle convenience is reduced, and the operation can be processed within 1 TDC . As described above, the large dead time of the controlled object generally impairs controllability compared to the case where the dead time is small, and in particular, becomes remarkable in adaptive control. Waste time can be greatly reduced, and controllability can be improved.

The above can be realized by taking several control cycles k of several to one for each cylinder. More specifically, in the case of a four-cylinder internal combustion engine, Equation 4 is replaced with Equation 13; Equation 8 is replaced with Equation 14; Equation 9 is replaced with Equation 15; It can be changed as shown in Equation 18.

u (k-4) u (k-8) u (k-12) y (k)]

^ (k) = 0 (k-) + Γ (k-) Γ (k- xd) e * (k)

λ 2 (k) Γ (k-4) Γ (k-d) ^T (k-xd) Γ (k-4)

Γ (k-4)

,, (k) λ! (K) + λ ₂ (k) ^T (k-4xd) Γ (k-4) r (k-4xd)

•. 'Number 1 5 2 o

D (z " ¹ ) y (k) — 0 ^T (k— 4) (k-1 4xd)

e * (k) = number 1 6

+ r ^T (k-4xd) r (k-4) r (k-4xd)

A ₃ (k) = 1

And + ^T (k-4x <l) Γ (k-1 4) Γ (k-4xd) ti (O)

Number 1

KSTR (k) =

KCMD (k-4xd ') -s ₀ xKACT (k) -r, xKSTR (k-4)-r ₂ xKSTR (k-8)-r ₃ xKSTR (k-12) b

Accordingly, in the configuration shown in FIG. 9 as well, the control cycle (operation cycle) is set for each TDC of all cylinders, that is, synchronized with the TDC of all cylinders in the configuration shown in FIG. It is possible to reduce the order of matrices and vectors used in the calculation while calculating the adaptive parameters. Of course, even if the control cycle is set for each cylinder and the control cycle k of Equations 1 to 12 is set to K == the number of cylinders X k, and the configuration has internal variables for each cylinder, it goes without saying that the same operation is performed. . Here, K indicates the number of combustion cycles, and k indicates TDC. FIG. 10 is a diagram in which the configuration of FIG. 8 is rewritten focusing on the STR controller and the parameter adjusting mechanism. In FIG. 10, if the operation cycle m XTDC of the STR controller and the operation cycle n XT DC of the parameter adjusting mechanism are respectively set to m = n = 1, the configuration shown in FIGS. 8 and 9 is obtained. Here, if the input cycle of the parameter adjustment mechanism is synchronized with TDC and the dead time is d = 2, the configuration shown in FIG. 8 is obtained. On the other hand, the input cycle of the If the dead time is d = 3, the configuration shown in Fig. 9 is obtained.

However, inputting the blunt output to the parameter adjusting mechanism in synchronization with the combustion cycle to perform the operation (operation) means operating in synchronization with the predetermined crank angle of the specific cylinder. It is strongly affected by the air-fuel ratio. As a result, when controlling the stoichiometric air-fuel ratio, for example, if the exhaust gas air-fuel ratio of the specific cylinder is in the lean direction and that of the remaining cylinders is in the rich direction, the adaptive controller (STR controller) operates. In some cases, the amount is adjusted in the rich direction so as to match the target value, so that the air-fuel ratio of the remaining cylinders may further increase the rich tendency.

For that purpose, in the illustrated device, as will be described later, the plant output is input to the parameter adjustment mechanism in synchronization with the combustion cycle to operate it, thereby reducing the number of elements of the adaptive parameter and reducing the number of matrix operations. And reduce the influence of the exhaust gas air-fuel ratio of specific cylinders. To achieve this, the following operation is performed.

The parameter adjustment mechanism operates in synchronization with the combustion cycle, that is, operates in synchronization with a predetermined crank angle of a specific cylinder among the four cylinders.However, the control amount y (k) is changed between combustion cycles. The average value of the detected air-fuel ratio KACT (k) for each TDC, for example, the average value of the detected air-fuel ratio KACT (k), for example, a simple average value, is input to the parameter adjustment mechanism, and the exhaust gas air-fuel ratio for that specific cylinder is obtained. So that it is not greatly affected by

Furthermore, for each predetermined crank angle, an average value is calculated for the adaptive parameter zero hat calculated by the parameter adjustment mechanism, and an average value is also calculated for the feedback correction coefficient KSTR0 calculated by the STR controller. As a result, the exhaust gas air-fuel ratio of the specific cylinder is not greatly affected. FIG. 11 is a subroutine flow chart showing the calculation work.

Referring to the figure, first, in S100, it is determined whether or not the engine is in a predetermined operating range. Here, the predetermined operation region is a low rotation region including idle. When it is determined in S100 that the cylinder is not in the predetermined operation range, the process proceeds to S102, in which the presently calculated air-fuel ratio KACT (k) calculated for the cylinder in S24 of FIG. About Of the previously calculated air-fuel ratio KACT (kl), the previous and previous calculated air-fuel ratio KA CT (k-2) for the previous and previous combustion cylinders, and the previous and previous calculated air-fuel ratio KACT (k-3) for the previous and previous combustion cylinders The average value KACTAVE is obtained, and it is used as the control output y (k), which is the plant output. That is, the control cycle is traced back three times, and the simple average value of the air-fuel ratios calculated during one combustion cycle for the four cylinders including the cylinder is obtained, and is set as the control amount y (k). With this method, the effect of the exhaust gas air-fuel ratio of a specific cylinder can be reduced.

Then, proceed to S104, and as shown at the end of Fig. 7, calculate the adaptive parameter 0 hat (10 from the control amount y (1 etc.) obtained by the parameter adjustment mechanism according to Equation 3 and input it to the STR controller. I do.

Then, proceed to S106, and calculate the adaptive parameter 6> the calculated value up to three control cycles before including the hat (k) this time, that is, ø hat (k), 0 hat during one combustion cycle. An average value of (k-1), 0 hat (k-2) and 0 hat (k-3), for example, a simple average value AVE-0 hat (k) is calculated. That is, the average value of 6> hat for four control cycles (one combustion cycle) corresponding to that of four cylinders is calculated for the adaptive parameter 0 hat (k) on the output side, not on the input side of the parameter adjustment mechanism. Input to the STR controller. Even if this method is used, the objective of reducing the shadow S of the exhaust gas air-fuel ratio of a specific cylinder can be achieved even if an average value of 0 hat (k) of four cylinders is input to the STR controller. Can be. Since 0 hat is calculated as a vector as shown in Equation 3, its average value is calculated by calculating the average value of each element s0, r1, r2, r3, b0 of the vector. I do. Note that an average value may be obtained for any of the elements, the change amount may be obtained for other elements in proportion thereto, and an average value of 0 hat may be calculated from them. In S106, a formula for calculating the average value of 0 hats including the meaning is schematically shown.

Then, the process proceeds to S108, where the STR controller calculates a feedback correction coefficient KSTR (k) according to Equation 12 based on the input value, and then proceeds to S110 to calculate the feedback correction coefficient KSTR ( k), including the calculated values up to three control cycles before, that is, the average value of KSTR (k), KSTR (kl), KSTR (k-2) and KSTR (k-3) during one combustion cycle, for example, simple average Calculate the value AVEKSTR (k). That is, the control input KSTR (k), which is the feedback correction coefficient of the fuel calculation system, is output instead of the parameter adjustment mechanism side. To achieve the purpose of reducing the effect of the exhaust gas air-fuel ratio of a specific cylinder even if the average value of the KSTR for the four control cycles (one combustion cycle) corresponding to that of the four cylinders is obtained for the STR controller to be applied. Because it can be.

On the other hand, if it is determined in S100 that the engine is in the predetermined operating range, the process proceeds to S112, where y (k) is calculated, that is, the current calculation obtained in S24 of FIG. The equivalent ratio KACT (k) is used as it is as the control amount (blunt output). Then, proceeding to SI 14, the adaptive parameter 0 hat (k) is calculated in the same manner as in the previous S 10, and proceeding to S 116, the feedback correction coefficient KSTR (k ) Is calculated.

In this way, the average value of the air-fuel ratios of all cylinders is obtained and input to the parameter — evening adjustment mechanism as the control amount y (k), so that the equivalence ratio of the specific cylinder (for example, the first cylinder) Is not greatly affected by the exhaust gas air-fuel ratio. Furthermore, for the STR controller output, the signal vector ^ is obtained using the values for the four control cycles including the latest value u (k) = KSTR (k) and input to the parameter adjustment mechanism Therefore, the effect of the exhaust gas air-fuel ratio of the specific cylinder is further reduced.

Also, the average value of the パラ -hat for the four control cycles (one combustion cycle) corresponding to that of the four cylinders for the zero-parameter (k) of the adaptive parameter of the output side, not the input side of the parameter adjustment mechanism, Is obtained and input to the STR controller, so that the purpose of reducing the effect of the exhaust gas air-fuel ratio of the specific cylinder can be achieved also by smoothing. Furthermore, instead of the parameter adjustment mechanism, the STR controller that outputs the KSTR (k), which is the feedback correction coefficient of the fuel calculation system, has four control cycles (one combustion cycle) corresponding to those of the four cylinders. Since the average value of KSTR is determined, the effect of the exhaust gas air-fuel ratio of a specific cylinder can be similarly reduced.

On the other hand, in S100, it is determined whether or not the engine is in a predetermined operating region, specifically, a low rotation region including idling, and when the result is affirmative, the average value is not calculated. Will not occur. That is, the control cycle becomes longer at low rotations, so that the response delay of the LAF sensor can be ignored. Conversely, since the phase of the detected air-fuel ratio KACT (k) and its average value KACTAVE are shifted as shown in Fig. 12, the same phenomenon occurs as when the dead time of the control system changes. Therefore, using KACTAVE (k) which is out of phase, Adaptive control may have adverse effects such as hunting. For this reason, smoothing is stopped when the engine is in a low rotation state such as during idling and is affected by this.

Note that, in the above, the average value AVE-β hat (k) of the adaptive parameters at 0 Hz calculated in S 106 should not be used to calculate the identification error signal e asterisk shown in Equation 10. I do. That is, since the identification error signal e asterisk is a function that evaluates the magnitude of the error between the detected air-fuel ratio and the target air-fuel ratio, if the AVE-0 hat 0 obtained as described above is used in the calculation of Equation 10, the error is Because it may be inaccurate, it is useful to provide an operating area that uses AVE-0 hat (k) only for the calculation of Eq. 8, but not for the calculation of Eq.

In the above description, the average values of the air-fuel ratio, 0 hat (k), and KSTR (k) are all used for S 102, S 106, and S 110, but any one of Or, of course, the appropriate two may be used. In addition, in the calculation of the average value at the time of engine start or the restart of the operation of the STR controller, if there is no past value, it goes without saying that an appropriate predetermined value is used.

When calculating the average value of the adaptive parameter 0 hat (k) and the feedback correction coefficient KSTR (k), it is not necessary to input those values to the parameter adjustment mechanism. This is because the feedback correction coefficient KSTR (k) calculated by the STR controller using the average value of the adaptive parameter 0 hat (k) has already reached a value that is not significantly affected by the exhaust gas air-fuel ratio of the specified cylinder. Because it is. Similarly, the average value of the feedback correction coefficient KSTR (k) calculated by the STR controller itself is a value that is not significantly affected by the exhaust gas air-fuel ratio of the specific cylinder.

The selection of the feedback correction coefficient indicated by S32 in the flowchart of FIG. 6 will be described.

FIG. 13 is a subroutine 'flow' chart showing the operation.

Referring to the figure, first, in S200, it is determined whether or not it is in the applicable area of the adaptive control system. For example, in an unstable combustion operation region such as an extremely low water temperature region, the accurate calculation air-fuel ratio KACT (k) is not obtained, so that the air-fuel ratio is outside the applicable region.In that case, the process proceeds to S210. Then, the output • fuel injection amount Tout (k) is calculated using the feedback correction coefficient KLAF (k) obtained by the PID control law. If it is determined that the adaptive control system is within the applicable area, the process proceeds to step S202, where the stability of the adaptive control system is determined using each element of the adaptive parameter 0 hat. The transfer characteristic of the feedback correction coefficient KSTR (k) is expressed as in Equation 19.

KSTRCz-') = (KC DCz- -SoKACTCz-O-Cr.z-' + r ^^ + raZ " ³ )

xKSTRCz "')} / b. ········································································ 1 9 Here, assuming that the adhesion correction is correct and there is no disturbance in the fuel operation system, the transfer characteristics of KSTR (k) and KACT (k) are It looks like 20.

KACT (z- ') = z- ³ KSTR (z- ¹ )

The transfer function from KCMDCk) to the correction coefficient KSTR (k) is as shown in Equation 21.

KSTRCz " ¹ ) 1

Number 21

KCMD (z- ¹ ) b. z ³ + nz ² + r ₂ z + r ₃ + s ₀

····

Here, since b 0 is a scalar quantity that determines the gain, it cannot be 0 or negative, so the denominator function f (z) of the transfer function of Equation 21 = b OZ ³ + rl Z ² + r 2Z + r 3 + s 0 is one of the functions shown in FIG. Therefore, it is determined whether or not the real root is within the unit circle. That is, as shown in FIG. 15, it is determined whether or not f (1-1) <0 or f (1)> 0. When the result is affirmative, the real root is within the unit circle, so that it can be easily determined whether the system is stable or not. Then, the process proceeds to S204 to determine whether or not the adaptive control system is unstable from the above. If the result is affirmative, the process proceeds to S206 to return the adaptive parameter vector 0 to the initial value. As a result, the stability of the system can be restored. Then, the process proceeds to S208, where the gain matrix Γ is corrected. Since the gain matrix Γ determines the change (convergence) speed of the parameter adjustment mechanism, this correction is performed so as to slow down the convergence speed. Here, each element of the gain matrix Γ is replaced with a smaller value. With this, the stability of the system can be restored similarly. Then, as shown in the figure, since the adaptive control system is unstable, as shown in the figure, the correction coefficient KF (k) based on the PID control law is used as the feedback correction coefficient, and it is used as the required fuel injection amount Tcyl ( k) and add the addition term TT0TAL to the product to determine the output fuel injection amount Tout (k).

If it is determined in S204 that the adaptive control system is not unstable, the process proceeds to S212, where the correction coefficient KST (k) by the adaptive control law is used as the feedback correction coefficient as shown in the figure. To calculate the output fuel injection amount Tout (k). At this time, if the average value of the feedback correction coefficient KSTR is obtained in S110 of the flowchart in FIG. 11, it goes without saying that the average value is used.

In the block diagram of FIG. 7, the output u (k) of the switching mechanism 400 is input to the STR controller and the parameter adjusting mechanism. This is to enable the calculation of the feedback correction coefficient KSTR by the adaptive control law even when the feedback correction coefficient KLAF by the PID control law is selected.

In this embodiment, as a result of the above-described configuration, although the parameter adjustment mechanism operates for each cylinder TDC, the number of elements in the adaptive parameter adjustment is 5 and the Γ matrix operation is 5 The load on the in-vehicle computer is reduced to X5, and the computation can be completed in 1 TDC with the in-vehicle computer of ordinary performance. On the other hand, the STR controller also calculates the feedback correction coefficient KSTR for every cylinder TDC, and by changing the feedback correction coefficient KSTR for every cylinder TDC, can respond to changes in the operating state as much as possible. In addition, controllability can be improved by greatly reducing the dead time.

Furthermore, when viewed from the cylinder-by-cylinder adjustment mechanism, each cylinder operates every combustion cycle.As a result, the cylinder always operates at a predetermined crank angle of the specified cylinder, for example, the first cylinder. Calculate the average value of the detected air-fuel ratio (control amount) for all the cylinders including the remaining cylinders during the combustion cycle, and input the average value to the parameter adjustment mechanism, or apply the Since the average value is calculated or the average value of the feedback correction coefficient KSTR, which is the output of the STR controller, is calculated and used, there is no inconvenience that only the combustion state of a specific cylinder is strongly reflected.

That is, if the feedback correction coefficient KSTR is determined based on the control amount for a specific cylinder, for example, when the air-fuel ratio of the first cylinder is rich and that of the other cylinders is lean, the feedback correction coefficient KSTR becomes empty. The decision was made to correct the fuel ratio in the lean direction, which spurred the leaning of the air-fuel ratio of the other cylinders. However, as a result of the average value for all cylinders, such inconvenience does not occur.

For further simplification, as shown in Fig. 16, the adaptive parameter 0 hat is synchronized not with every cylinder TDC but with the combustion cycle of a specific cylinder. The STR controller may be configured to use the same value for the adaptive parameter 0 hat several times a cylinder several times (corresponding to the case where m = 1 and n = 4 in Fig. 10). .

This method is particularly effective when the operable time decreases as the engine speed increases. At high engine speeds, the variation of the adaptation parameters required for each cylinder at 0 h is reduced, so that the controllability can be maintained even if the adaptation parameter of a specific cylinder is applied to all cylinders including other cylinders. The calculation time can be shortened without deteriorating the controllability because the deterioration of is small.

Furthermore, as shown in FIG. 17, if the STR controller is operated only once every 4 TDC in synchronization with the combustion cycle, the configuration can be further simplified. Although the control accuracy is reduced, some effects can be obtained with this configuration (corresponding to the case where m = n = 4 in Fig. 10).

Fig. 18 is a flow chart showing a second embodiment of the apparatus according to the present application, which is related to the setting of the gain matrix 用いる used for calculating the feedback correction coefficient KSTR.

The calculation of the feedback correction coefficient KSTR requires a gain matrix r (k) as is clear from the above equations (1) to (12). The second embodiment is based on Equation 9; = 1, λ ₂ = 0, that is, when the fixed gain algorithm is used, the off-diagonal elements of this -in matrix Γ0 are all set to 0 to reduce the calculation time and facilitate the setting. Was.

For the sake of explanation, consider the case where the operation of the internal variable Γ (k-d) is performed as an example. In the case of the first embodiment in which the key matrix Γ is a 5 × 5 matrix, the calculation of Γ is performed as shown in Expression 22 and 25 multiplications and 20 additions are required.

u (k-l-d)

Γ Ck-d) u (k-2-d)

u (k-3-d) y (k-d)

To gi, u (kd) + g ₁₂ u (kld) + + g ₁₅ y (kd)

gsiuCk-d) + + g _S5 y (kd) Equation 22 If all non-diagonal elements of gain matrix Γ are set to 0, it can be expressed as Equation 23, and the operation can be reduced to 5 multiplications Can be. 2 g

gl 1 gl2 gl3 gl4 gl S u (k-d)

g21 g22 g23 g24 g26 u (k-l-d)

Γ (k-d) = gsi g32 g33 g34 g3 S u (k-2-d)

Five

g, k41 g42 g "g" g "u (k-3-d)

g51 gS2 g63 gS4 g55 y (kd)

g ₂₂ u (kld)

Number 2 3 g ₅ sy (kd)

In addition, when the non-diagonal elements of the gain matrix Γ are all set to 0 to calculate the adaptive parameter Θ J (k), Equation 24 is obtained.

0, (kl) 0 ₂ (kl)

^ (k) = 0 ₃ (k-1) + Γ rCk-d) e * (k)

6> ₄ (kl) e * (k) number 2 4

As a result, the matrix elements _{gu. G 2 2. G 33.} g ". G" corresponded to only one element of the change speed of each element of the adaptive parameters Isseki (hearts preparative (k) (k) If the off-diagonal elements of the gain matrix Γ are not 0, the calculation of the adaptive parameter 0 hat (k) as can be seen from Equations 2 2 and 24 Is given by the following equation 25. In order to determine the rate of change of one element of 0 hat (1), it is necessary to consider five variables corresponding to all elements of ζ (kd). By setting all off-diagonal elements of the gain matrix 0 to 0, the calculation time can be reduced and the setting can be facilitated.

Equation 25 Further, the inventors conducted a test, and found that the five setting elements g H to g _{55 in} the ₅₅ matrix, assuming that some of them have the same value, have the adaptive parameter 6> hat (k) It has been found that the ratio of the change speed of each element is appropriate and the controllability is the best. For example, gugg sa g-g. With such placing, it is possible to reduce the Setti ring element into two g and g _66, it is possible to reduce the man-hours for Setti ring, for example, the internal variable ^T (kd) ^Γ r (k operation -d) is as few 26, _n multiplication is 1 twice

= g {u (kd) ² + u (kld) ^: + u (k-3-d) ² } + g ₅₅ y (kd) ^;

Equation 2 6 On the other hand, if g H to g ₄₄ take different values, the above operation becomes as shown in Equation 27, and the multiplication increases to 15 times. r ^T (kd r Γ (kd) = g, iu (kd) ² + + g ₅₅ y (kd) ^{; From} number 2 and above, setting some of g ^ g ss to the same value The number of elements can be reduced, the calculation time can be further reduced, and the ratio of the change speed of each element of the adaptive parameter ø hat (k) can be made appropriate, so that the controllability can be improved. At this time, if gu ^ gg ss gg is used, it goes without saying that the effect is most apparent.

Furthermore, for example, because the combustion is unstable, taking the operating region even plant output becomes unstable as an example, by reducing the above g _55, it is possible to obtain such suppression hunting so (k). As described above, setting the off-diagonal element of the gain matrix 0 to 0 has a great advantage that the control characteristics can be easily set. In addition, by changing the gain matrix によって depending on the operating region, it is possible to always obtain the optimal controllability for the engine.

In that case, g H to g ₅₅ are determined by the RAM 74 in the control unit 34 according to the operating state. In the book. More specifically, it is stored according to the operating state of the control device of the engine such as canister purge, exhaust gas recirculation, etc., in addition to the operating state. In this case, gugss may be all the same value, all different values, or some same value. In addition,

In this case, the off-diagonal element of the gain matrix Γ may be used as long as the capacity of the RAM 74 or the operation time has room.

On the basis of the above, a second embodiment of the apparatus according to the present application will be described with reference to a flow chart of FIG.

First, in S300, the engine operating parameters such as the engine speed Ne and the intake pressure Pb and the operating states of the exhaust gas recirculation mechanism or the canister / purge mechanism described above are read, and the program proceeds to S302. It is determined whether or not it is in the idle area. If the determination is affirmative, the process proceeds to S30 to search for the idle Γ map. On the other hand, when it is determined in S302 that the variable valve timing mechanism is not in the idle area, the process proceeds to S306, in which it is determined whether the variable valve timing mechanism is operated with the Hi valve timing characteristic, and the result is affirmed. If so, proceed to S308 to search for a Γ map for Hi valve timing. If not, proceed to S310 to search for a Γ map for L0 valve timing.

Fig. 19 shows the characteristics of the Γ map for L0 valve timing. As shown in this map, a matrix element g ^ gss is searched from the engine speed Ne and the intake pressure Pb. The Γ maps for idle and Hi valve timing also have similar characteristics. In this map, the value of the gain matrix Γ is searched based on the intake pressure Pb indicating the engine load, so that the optimal gain matrix value is obtained even in a deceleration operation state where the engine load fluctuates rapidly. be able to.

Then, the process proceeds to S312, where it is determined whether the EGR (exhaust gas recirculation mechanism) is operating. Modify Γ. More specifically, the fuel correction coefficient KEGRN for the exhaust gas recirculation rate is searched from the table showing its characteristics in Fig. 20 to find the correction coefficient Kr EGR, and the obtained correction coefficient Kr EGR is multiplied by the gain matrix Γ. to correct. The reason why the gain matrix is corrected according to the fuel correction coefficient KEGRN for the exhaust gas recirculation rate is that the correction coefficient Kr EGR is, as shown in the figure, a disturbance as the fuel correction coefficient KEGRN for the exhaust gas recirculation rate decreases as the exhaust gas recirculation rate increases. , The stability of the adaptive control system The gain matrix is set so as to decrease as the fuel correction coefficient KEGRN for the exhaust gas recirculation rate decreases, so as to enhance the performance.

The exhaust gas recirculation rate KEGRN is a coefficient for multiplying and correcting the fuel injection amount, and is determined to be, for example, 0.9. However, the gist of the present invention is not in the determination of the exhaust gas recirculation rate itself, and the determination of the exhaust gas recirculation rate is described in, for example, Japanese Patent Application No. 6-294, 014 proposed earlier by the present applicant. Description is omitted.

Subsequently, the flow proceeds to S316 to determine whether the canister / purge mechanism is operating. If the result is YES, the flow proceeds to S318 to correct the gain matrix て according to the purge mass. More specifically, a correction coefficient ΚΓΡΙ Ϊ is obtained from the fuel correction coefficient KPUG for the purge mass by searching a table showing the characteristics in FIG. 21, and the obtained correction coefficient Kr PUG is multiplied by the gain matrix 補正 for correction. . As shown in the figure, the correction coefficient KrPUG is such that the fuel correction coefficient KPUG for the purge mass decreases as the purge mass increases, and the disturbance increases accordingly.Therefore, the gain matrix につれてIs set to be small. The fuel correction coefficient KPUG for the purge mass is also described in, for example, Japanese Patent Application Laid-Open Nos. Hei 6-101 and 522 previously proposed by the present applicant, and therefore the description thereof is omitted.

Subsequently, the process proceeds to S320 to correct the gain matrix Γ according to the detected atmospheric pressure Pa. More specifically, from the detected atmosphere EEPa, a table showing the characteristics shown in Fig. 22 is searched to find the correction coefficient KrPa, and the obtained correction coefficient Κ Γ 乗算 is multiplied by the gain matrix Γ for correction. . The reason for correcting the gain matrix 応じ according to the detected atmospheric pressure Pa is that the detected atmospheric pressure Pa decreases, that is, the charging efficiency decreases as the altitude at which the engine is located increases. Since the disturbance occurs to the data set at normal pressure, the gain matrix Γ is set to decrease as the detected atmospheric pressure Pa decreases so that the stability of the adaptive control system increases. .

Then, the process proceeds to S322 to correct the gain matrix Γ according to the detected water temperature Tw. More specifically, a correction coefficient Kr TW is obtained by searching a table showing the characteristics in FIG. 23 from the detected water temperature Tw, and the obtained correction coefficient KrTW is multiplied by a gain matrix to perform correction. The reason for correcting the gain matrix Γ according to the detected water temperature Tw is that the correction coefficient Κ Γ TW is as shown in the figure, and combustion does not occur when the detected water temperature Tw is at low or high water temperature. Since it becomes stable, it causes disturbance to the data set at room temperature.In order to increase the stability of the adaptive control system, reduce the gain matrix Γ at low or high water temperature. Is set.

As described above, in the second embodiment, the gain matrix for determining the change (convergence) speed of the adaptive parameter 0 hat is determined appropriately according to the operating state. And controllability is improved.

Although the second embodiment determines the gain matrix Γ with a fixed gain, it is also possible to use a variable gain algorithm, in which case the initial value of each element of the gain matrix Γ is It is also possible to make corrections in the operating state as described above, and to set the values when the operating state changes.

Further, in the second embodiment, the fixed gain algorithm has been described, but the calculation of the gain matrix r (k) is performed based on an operation rule other than the fixed gain algorithm such as the variable gain algorithm shown in Expression 9. In this case, the calculation of the off-diagonal element of the gain matrix Γ 0 is not performed and the value is fixed to 0, thereby realizing the reduction of the amount of calculation and the simplification of the setting shown in the second embodiment. Needless to say, this is possible.

In the first embodiment and the second embodiment, the gain matrix Γ is calculated with a fixed gain, but in the third embodiment, the calculation is performed using an algorithm other than the fixed gain, and the adaptive When the control result using parameters (blunt output, more specifically, the detected air-fuel ratio KACT) shows good behavior, if the calculated value is stored according to the operating state of the engine, it can be used again in that region. It is not necessary to calculate the gain matrix Γ 0, and at the same time, the optimal gain matrix Γ 0 can be always used in that region, and controllability is improved. At this time, 加工 0 stored may be a processed value such as an average value between 4 TDCs. Note that when the gain matrix Γ is calculated from the fixed gain algorithm, it is determined that the behavior of the brand output is not good. The gain matrix r (kl) at that time starts as the initial value stored for each operation area The description will be made with reference to FIG. 24 on the premise of the above. This is an operation to be performed when searching for a map of a gain matrix の such as S308, S310, or S304 in FIG. 18 of the flowchart of the third embodiment.

In the following, a map of the gain matrix 同様 similar to that shown in the second embodiment is searched from the engine speed Ne and the intake pressure Pb at S400, and the program proceeds to S402 to execute the An appropriate method was used to determine whether the behavior of the detected air-fuel ratio KACT, which is the output, was good, and if not, proceeded to S404 to calculate the gain matrix Γ0, and proceeded to S406 to search. It is stored in a predetermined area of the map. If the result in S402 is affirmative, the process immediately proceeds to S406. Whether the behavior of the detected air-fuel ratio KACT in S402 is good or not is determined by, for example, determining that the detected air-fuel ratio KACT between 10 TDC is within a predetermined value of the target air-fuel ratio KCMD soil.

Since the third embodiment is configured as described above, when the behavior of the detected air-fuel ratio KACT is good, the calculation of the gain matrix Γ 0 is performed by a simple map search without using the arithmetic expression shown in Expression 9. Since it can be performed, the amount of calculation can be reduced. Furthermore, if the fluctuation of the detected air-fuel ratio KACT is not good, the optimal gain matrix Γ0 is recalculated and learned for each operating region of the internal combustion engine to cope with the deterioration over time of the internal combustion engine. Since the behavior of the detection equivalence ratio KACT0 can always be improved, controllability can be improved.

FIG. 25 is a flow chart showing a fourth embodiment of the apparatus according to the present application.

In the fourth embodiment, a dead zone is provided in the characteristics of the detected air-fuel ratio KACT so that the adaptive control system does not become unstable. In other words, since the STR controller operates so that the detected air-fuel ratio KACT matches the target air-fuel ratio KCMD, if the detected air-fuel ratio KACT input to the STR controller matches the target air-fuel ratio KCMD, the adaptive parameters Almost no change. Therefore, when the detected air-fuel ratio KACT fluctuates minutely from a small disturbance such as sensor noise, the adaptive control system is not affected by such a small disturbance, so that unnecessary overcorrection is not performed. As shown in Fig. 26, a dead zone was set near the target air-fuel ratio KCMD in the characteristics of the detected air-fuel ratio KACT. Specifically, the detected air-fuel ratio KACT was made the same in the range of KCMD-yS to KCMD + HI. Referring to the flow chart of FIG. 21, the detected air-fuel ratio KACT is compared with a predetermined lower limit value KCMD-8 at S500, and if it is determined that the detected air-fuel ratio KACT is higher than the predetermined value, the flow proceeds to S502. The detected air-fuel ratio KACT is compared with the upper limit predetermined value KCMD + one. If it is determined in S502 that the detected air-fuel ratio is equal to or smaller than the predetermined value KCMD + α, the process proceeds to S504, where the detected air-fuel ratio KACT is set to a predetermined value, for example, the target air-fuel ratio KCMD. When the detected air-fuel ratio KACT is determined to be lower than the lower limit predetermined value KCMD-y8 in S500, or when the detected air-fuel ratio KACT is determined to be higher than the upper limit predetermined value KCMD + in S502. Terminates the program immediately. Therefore, in that case, the detected value is used as it is as the detected air-fuel ratio KACT. Through the above processing, as shown in FIG. 26, a dead zone can be provided near the target air-fuel ratio KCMD in the characteristics of the detected air-fuel ratio KACT.

Since the fourth embodiment is configured as described above, for example, even when the detected air-fuel ratio KACT fluctuates minutely, the STR controller can operate stably without being affected by the fluctuation, and thus a good control result can be obtained. Can be obtained. In S502, the target air-fuel ratio KCMD is set as the detected air-fuel ratio. However, any other value in the range from KCMD-β to KCMD + may be used.

FIG. 27 is a flow chart showing a fifth embodiment of the apparatus according to this application.

The fifth embodiment prevents instability of the adaptive control system as in the fourth embodiment, and provides upper and lower limit values for the identification error signal e asterisk to provide a stable adaptive parameter. I got an evening.

That is, as is apparent from Equation 8, by limiting the value of the identification error signal e asterisk to a certain range or less, it is possible to limit the changing speed of the adaptive parameter 0 hat. As a result, it is possible to prevent overshoot from the optimal value of the adaptive parameter 0 hat (k) over time and consequently to operate the adaptive control system stably to obtain a good control result. Because you can.

Explaining in accordance with the flowchart of FIG. 27, first, the identification error signal e asterisk (k) calculated in S600 is compared with the upper limit a (shown in FIG. 28), and it is determined that the value is exceeded. If so, the process proceeds to S602, and a predetermined value, for example, the upper limit a is set as the identification error signal e asterisk (k). On the other hand, the identification error signal e If it is determined that the threshold value (k) is equal to or smaller than the upper limit value a, the processing proceeds to S604, where the calculated identification error signal e asterisk (k) is compared with the lower limit value b (shown in Fig. 28). When it is determined that the value is less than the predetermined value, the process proceeds to S606, and the second predetermined value, for example, the lower limit value b is set as the identification error signal e (asterisk). If it is determined in S604 that the identification error signal e asterisk (k) is equal to or greater than the lower limit b, the program is immediately terminated. Therefore, in that case, the identification error signal e risk (k) remains the calculated value.

Since the fifth embodiment is configured as described above, the changing speed of the adaptive parameter 0 hat (k) is limited by limiting the value of the identification error signal e asterisk (k) within a certain range. be able to. As a result, it is possible to prevent an overrun with respect to the optimum value of the adaptive parameter 0 hat (k), and to operate the adaptive control system stably to obtain a good control result.

In S602 to S606, the value of the identification error signal e asterisk (k) is set to the upper and lower limits, but may be an appropriate value between the upper and lower limits, or It may be an appropriate value.

In the sixth embodiment, in the STR controller shown in the first embodiment, the adaptive error 6> identification error signal e that determines the hat e is used as the denominator of the asterisk in the equation (10) By making the constant 1 variable, the rate of change was stabilized and controllability was improved.

The sixth embodiment is based on the premise that the adaptive control as shown in the drawing is realized by a low-level in-vehicle microcomputer by limiting the range of change of the intermediate variables used in the calculation by the adjusting mechanism. This is described in Japanese Patent Application Laid-Open No. Hei 6-161, 511 previously proposed by the present applicant, and therefore description thereof is omitted.

That is, in the theoretical formula, the identification error signal e asterisk (k) is calculated as shown in Expression 10. Now, suppose that (1 and y (k) are multiplied by 1 × 10 (hereinafter j)) and input to the parameter adjustment mechanism. (kl) is constant for a fixed gain). 1 1

1 + r ^T (kd) r (kl) ζ (kd)

10 10 Here, the right term is the square of the coefficient by which (k) and y (k) are multiplied. If this coefficient is a small value of 1 or less (in the example, 1/10 ² = 1Z1 00), It is much smaller than left term = 1. Therefore, no matter how the right term changes, the denominator of the identification error signal e asterisk (k) is close to 1, and the rate of change of the identification error signal e asterisk (k) before multiplication by the coefficient changes. Would. To solve this problem, set the left term to a value other than 1. As a guideline, the coefficients of the When j, if put and j ^2, can be the same change rate as before multiplication coefficient j.

Conversely, the rate of change of the identification error signal e asterisk (k) is proportional to the rate of change (convergence) of the adaptive parameter 0 hat (k), so that 0 (k) is calculated using equation (8). Therefore, by giving a value other than j ² , the rate of change of the adaptive parameter overnight (k) can be changed. Therefore, in the arithmetic expression of the denominator of the identification error signal easter risk (k) shown in Expression 29, i in the expression takes a value other than 1, that is, i ≠ l.

e * (k) = number 29 i + jr ^T (kd) r (kl) jr (kd) Referring to the flow chart of FIG. 29, first, the identification error signal e Adaptive parameter 6 due to risk (k) 6> Change in hat (k) (convergence) It is determined whether or not to perform an operation that makes the speed variable. If affirmative, the process proceeds to S702 and i is set to a value other than 1, More specifically, i is determined by searching a map showing the characteristics in FIG. 30 from the detected engine speed Ne and the intake pressure Pb. On the other hand, the same change rate as before at the i and j ² proceeds to S 704, multiplied by a coefficient j if negative in S 700 And Incidentally, j is so constant, in the map characteristic shown in the third 0 Figure, the value of i is set a value in consideration of j ^2, for example, i = j ² x 0. 5 no such to i = j ² x 2 and. Specifically, j is usually set to a value smaller than 1. For example, if j = 1/10, i = j ² = 1 Z 1 0 0 if negated by S 7 0 0 Becomes Therefore, even if the result is affirmative in S700, the i-map value is set in FIG. 30 so that i = 1100 is the center, for example, between 150 and 1200. At this time, the smaller (i.e., 1/200) i, the faster the change (convergence) of the adaptive parameter Θ (k), and the larger i (e.g., 1Z50), the more adaptive parameter. The change (convergence) speed of 0 hat (k) overnight decreases. Accordingly, in FIG. 30, the i-map value is more specifically large (for example, 1/50) at high rotation and high load, and small (for example, 1/2000) at low rotation and low load. Set as follows.

Since the sixth embodiment is configured as described above, by changing the constant of the identification error signal easter risk that determines the adaptive parameter at 0 Hz, the adaptive parameter can be harmonized with the coefficient for the input. The change speed of the evening hat is stable, and good controllability can be achieved.

Although the STR controller used in the first embodiment is taken as an example in the sixth embodiment, the adaptive controller is not limited to the one shown in the first embodiment. As long as they operate based on the Landau et al.'S adjustment rule, all are valid including the MR ACS type adaptive controller.

In the seventh embodiment, the control cycle of the parameter adjustment mechanism and the STR controller shown in the first embodiment is made variable, and the operating state, specifically, The control cycle is determined according to the rotation speed. In other words, by changing the parameter control mechanism of the adaptive controller or the control cycle of the controller in accordance with the operation state, the calculation load can be reduced as much as possible, and the operation can be performed even in the operation state where the calculation time is short, such as at high speed. It is possible to perform control and realize good controllability.

Referring to the flowchart of FIG. 31 and the flowchart, first, the device detected in S800 The engine speed Ne is compared with a predetermined value Nepl.If it is determined that the detected engine speed Ne is less than the predetermined value Nepl, the process proceeds to S802 and the detected engine speed Ne is determined by another predetermined value. Compare with Necl. When it is determined that the engine speed Ne detected in S802 is another predetermined value Necl not grooved, the process proceeds to S804, in which the parameter adjusting mechanism (abbreviated as P in FIG. 31) and the STR controller ( The control cycle (abbreviated as C in Fig. 1) is for each TDC.

FIG. 32 is an explanatory diagram of the operation of the flowchart shown in FIG. 31. When the predetermined value Nepl. Necl is in a relatively low rotation range as shown in FIG. Priority is given to both the parameter adjustment mechanism and the STR controller, as shown in Figs. 8 and 9, for each TDC.

In FIG. 31, when it is determined that the engine speed Ne detected at S802 exceeds the predetermined value Necl, the routine proceeds to S806, where the detected engine speed Ne is compared with the predetermined value Nec2. If determined to be less than the value, the process proceeds to S808, where the parameter adjustment mechanism is operated every TDC, and the STR controller is operated every two TDCs. On the other hand, when it is determined that the engine speed Ne detected in S806 is equal to or more than the predetermined value Nec2, the process proceeds to S810, in which the parameter adjustment mechanism operates every TDC, and the STR controller operates every four TDC.

When it is determined that the engine speed Ne detected in S800 is equal to or greater than the predetermined value Nepl, the process proceeds to S812 and compares the detected engine speed Ne with a predetermined value Nep2. When it is determined, the process proceeds to S814, and the detected engine speed Ne is compared with the predetermined value Nec3. When it is determined that the detected engine speed Ne is less than the predetermined value Nec3, the process proceeds to S816. The parameter adjustment mechanism operates every two TDCs, and the STR controller operates every TDC.

On the other hand, when it is determined that the engine speed Ne detected in S814 is equal to or greater than the predetermined value Nec3, the process proceeds to S818 and compares the detected engine speed Ne with the predetermined value Nec4. If it is determined that the STR controller is in operation, the process proceeds to S820, and the STR controller operates the parameter adjustment mechanism every 2 TDC. If the engine speed Ne detected in S818 is determined to be equal to or greater than the predetermined value Nec4, the process proceeds to S822, where the parameter adjustment mechanism is provided every 2 TDC, and the STR controller is provided every 4 TDC. Make it work. Further, when it is determined that the engine speed Ne detected in S8 12 is equal to or more than the predetermined value Nep2, the process proceeds to S824 and the detected engine speed Ne is compared with the predetermined value Nep3, and it is determined that there is no groove. In step S826, the detected engine speed Ne is compared with a predetermined value Nec5.If it is determined that the detected engine speed Ne is less than the predetermined value Nec5, the process proceeds to step S828 to determine the parameter. The adjustment mechanism operates every 4 TDCs, and the controller operates every TDC (shown in Fig. 16).

On the other hand, if it is determined that the engine speed Ne detected in S826 is equal to or higher than the predetermined value Nec5, the process proceeds to S830 and compares the detected engine speed Ne with the predetermined value Nec6. When it is determined, the process proceeds to S832, the parameter adjustment mechanism is operated every 4 TDC, the STR controller is operated every 2 TDC, and the engine speed Ne detected in S830 is equal to or more than the predetermined value Nec6. If it is determined that this is the case, the procedure proceeds to S83, in which the parameter adjustment mechanism and the STR controller are operated every 4 TDC (as shown in Fig. 17). When it is determined that the engine speed Ne detected in S824 is equal to or more than the predetermined value Nep3, the process proceeds to S836 to stop the adaptive controller STR.

As described above, in the seventh embodiment, the control cycle of the STR controller and the parameter adjustment mechanism of the adaptive controller are determined in accordance with the engine speed. For example, adaptive control can be performed even in an operation state where the calculation time is short, and good controllability can be realized.

In the above, the operating state of the adaptive controller STR shown in FIG. 32 does not need to be provided in all of 1 to 10 (indicated by circled numbers in the figure), and depends on the capacity of the engine and the CPU of the control unit configuration. May be appropriately selected. For example, 1,3,5,9,10,0,1,3,6,9,10,0,7,7,9,10,0,1,10,0,1,4,7,7 It may be selected as 10 or the like.

Furthermore, although the engine speed was used as the operating state, the present invention is not limited to this, and may be determined in consideration of the engine load. In such a case, for example, in a high load state, there is little change in the adaptive parameter 0 hat, so it may be possible to process the parameter adjustment mechanism every 4 TDCs.

FIG. 33 shows an eighth embodiment of the apparatus according to the present application, and is a subroutine flow showing the operation of calculating the average value such as the feedback correction coefficient KSTR similar to FIG. 10 is a chart.

In the case of the first embodiment, in order to avoid the influence of the exhaust air-fuel ratio of the specific cylinder, an average value is basically obtained for the element that determines the feedback correction coefficient KSTR, and a predetermined operating state is determined. That is, the calculation of the average value is stopped in the idle state.

In the eighth embodiment, in contrast to the first embodiment, an average value is not calculated in principle, and only when a predetermined operating state, specifically, when exhaust gas recirculation (EGR) is performed, the average value is calculated. The value was calculated.

To explain this, when the exhaust gas is recirculated in the exhaust gas recirculation mechanism described above, depending on the operation state, the exhaust gas is not evenly introduced into the four cylinders, and for example, a large amount of the exhaust gas is introduced into the cylinder close to the recirculation port 12 1 b. Exhaust gas may be inhaled and a small amount may be inhaled to distant cylinders. Therefore, in such a case, the air-fuel ratio KACT (k) detected for each TDC is greatly affected by the specific cylinder, and if the detected air-fuel ratio KACT (k) is used, the equivalent In order to adjust only the ratio to the target air-fuel ratio, the control values of all cylinders are offset by the deviation of that cylinder, and the air-fuel ratio of other cylinders is shifted. Therefore, to avoid this, it is desirable to calculate the average value as shown in the figure.

Referring to FIG. 33, it is determined whether or not EGR (exhaust gas recirculation control) is being executed in S900, and when the result is affirmative, the process proceeds to S902 and thereafter, and the first operation is performed with respect to FIG. The average value of KACTAVE etc. is obtained in the same way as described in the above form. On the other hand, if the result in S900 is negative, the process proceeds to S912, and the same processing as described in the first embodiment with reference to FIG. 11 is performed.

Since the eighth embodiment is configured as described above, even when the exhaust gas is recirculated, the controllability is improved without being greatly affected by the specific cylinder.

FIG. 34 shows a ninth embodiment of the apparatus according to the present application, which is a subroutine flow chart showing the operation of calculating the average value such as the feedback correction coefficient KSTR similar to FIG. 33.

As in the case of the exhaust gas recirculation, when the gas is supplied after the canister purge is executed, the gas may not be uniformly introduced into the cylinder depending on the operating condition. The same problem as described in the embodiment may occur. The ninth embodiment addressed this.

Explaining with reference to FIG. 34, it is determined at S1000 whether or not the purge is being performed.If the result is affirmative, the process proceeds to S1002 and thereafter to perform the first operation with respect to FIG. The average value of KACTAVE etc. is obtained in the same way as described in the form. On the other hand, if the result in S100 is negative, the process proceeds to S102 and thereafter, and the same processing as described in the first embodiment with reference to FIG. 9 is performed.

Since the ninth embodiment is configured as described above, the controllability is improved without being greatly affected by the specific cylinder even when the purge and purge is performed.

Although not shown, when the atmospheric pressure Pa is low, that is, when the combustion is unstable, such as when the vehicle is located at a high altitude, at a low water temperature, or during lean burn operation, Similarly, it is desirable to obtain an average value, whereby controllability can be improved.

FIGS. 35 and 36 are a door, a chart and a block diagram showing a tenth embodiment of the apparatus according to the present application.

Referring to FIG. 36 first, in the case of the tenth embodiment, the feedback loop (correction) of the exhaust system assembly equivalent ratio based on the PID control law is added to the configuration of the first embodiment. In addition to removing the coefficient KLAF, a cylinder-specific feedback loop (correction coefficient #nKLAF) consisting of the same PID control law was inserted.

That is, from the output of a single air-fuel ratio sensor disposed in the exhaust system collecting section, the above-mentioned applicant uses the observer previously proposed in Japanese Patent Application Laid-Open No. 5-180400 to empty the air of each cylinder. The fuel ratio #n AZF (n: cylinder) is estimated, and the feedback correction coefficient for each cylinder is determined by using the PID control law according to the deviation between the estimated value and the target value of the predetermined cylinder-specific air-fuel ratio FZB # nKLAF was calculated and multiplied and corrected by the output fuel injection amount Tout.

More specifically, the feedback correction coefficient #nKLAF for each cylinder is a value obtained by dividing the collection air-fuel ratio by the previous calculated value of the average value of the feedback correction coefficient #nKLAF for each cylinder (this is calculated as described above. This is called the target value j of the cylinder-specific air-fuel ratio FZB. Therefore, this is different from the target air-fuel ratio KCMD) and the deviation from the estimated air-fuel ratio # nA / F Determined using the PID control law. Since this is shown in Japanese Patent Application No. 5-251,138, which was separately proposed by the applicant, the description is omitted. The illustration of the adhesion correction compensator is omitted.

Further, in the tenth embodiment, a sampling block (shown as Sel-VOBSV in the figure) for sampling the LAF sensor output at an appropriate timing is provided, and the same type of sampling block is used for the STR controller (see FIG. Is shown as Sel-VSTR).

Here, the sampling block and the observer will be described. The sampling operation block is shown as “Set V0BSV” in FIG.

Since the exhaust gas is discharged in the exhaust stroke in the internal combustion engine, the behavior of the air-fuel ratio in the exhaust system assembly of the multi-cylinder internal combustion engine is clearly synchronized with the DC. Therefore, when the wide-range air-fuel ratio sensor described above is provided in the exhaust system of the internal combustion engine and the air-fuel ratio is sampled, it must be performed in synchronization with TDC. However, a sample of the control unit (ECU) that processes the detected output Depending on the timing, the behavior of the air-fuel ratio may not be accurately grasped. That is, for example, when the air-fuel ratio of the exhaust system collecting part with respect to TDC is as shown in Fig. 37, the air-fuel ratio recognized by the control unit is a completely different value depending on the sample timing as shown in Fig. 38. Becomes In this case, it is desirable to sample at a position where the actual change in the output of the air-fuel ratio sensor can be grasped as accurately as possible.

Further, the change in the air-fuel ratio also depends on the exhaust gas arrival time to the sensor and the sensor reaction time. Among them, the time to reach the sensor varies depending on the exhaust gas pressure, exhaust gas volume, and the like. Furthermore, since sampling in synchronization with TDC means sampling based on the crank angle, it is inevitably affected by the engine speed. Thus, detection of the air-fuel ratio largely depends on the operating state of the engine. For this purpose, for example, in the technology described in Japanese Patent Application Laid-Open No. H11-313,644, the suitability of detection is determined at each predetermined crank angle. In the rotational speed range, it may not be possible to cope with the problem, and at the time when the detection is determined, the inflection point of the output of the air-fuel ratio sensor may be exceeded.

Fig. 39 is a flow chart showing the sampling operation of the LAF sensor. However, since the detection accuracy of the air-fuel ratio is closely related to the above-described estimation accuracy of the observer, the air-fuel ratio estimation by the observer will be briefly described before the description of FIG.

First, in order to accurately separate and extract the air-fuel ratio of each cylinder from the output of one LAF sensor, it is necessary to accurately clarify the detection response delay of the LAF sensor. Therefore, this delay was simulated as a first-order delay system, and a model as shown in Fig. 40 was created. Here, if LAF: LAF sensor output, AZF: input AZF, the state equation can be expressed by the following Equation 30.

LAF (t) = LAF (t)-aA / F (t) ····················································································································· Fig. 41 shows Equation 31 in a block diagram.

L AF (k + 1) = H LAF (k) + (11) A / F (k)

. (! 1/2) • ' number 3 1 here, shed ^{= 1 + αΔΤ + α 2 ΔΤ} 2 + (! 1/3) 3厶T:

+ (1/4!) A ⁴ ΔΤ ⁴ Therefore, by using Equation 31, the true air-fuel ratio can be obtained from the sensor output. In other words, when Equation 31 is transformed, Equation 32 is obtained, and the value at Time k-1 1 can be inversely calculated from the value at Time k as in Equation 33. What

A / F (k) = {LAF (k + 1) one LAF (k)} / C l-a)

• Number 3 2

A / F (k-1) = {LAF (k)-aLAF (k-1)} / (1-a

Equation 3 3 More specifically, if Equation 3 1 is represented by a transfer function using Z-transformation, Equation 34 is obtained.Therefore, the previous input air-fuel ratio is obtained by multiplying the inverse transfer function by the current LAF sensor output LAF. It can be estimated in real time. Figure 42 shows a block diagram of the real-time AZF estimator.

(z) = (1-hi) Z (Z-) number 34 Next, the method of separating and extracting the air-fuel ratio of each cylinder based on the true air-fuel ratio obtained as described above will be described. Assuming that the air-fuel ratio in the exhaust system is a weighted average considering the time-dependent contribution of the air-fuel ratio of each cylinder, the value at time k is expressed as shown in Equation 35. did. Note that “F / A ratio” is used here because F (fuel amount) is the control amount, but “Air / fuel ratio” will be used in the following description for ease of understanding unless there is a problem. Note that the air-fuel ratio (or fuel-air ratio) means a true value obtained by correcting the response delay previously obtained in Equation 34. [F / A] (k) Ci [FZA] + C ₂ [FZA]

+ C ₃ [FZA] + C * [FZA]

[F / A] (k + 1) Ci [FZA] + C ₂ [FZA]

+ C ₃ [FZA] + C ₄ iF A ti i]

[FZA] (k + 2) d [FZA « ₄ ] + C ₂ [FZA]

+ C ₃ [F / A «,] + C ₄ [F / A« ₃ ]

Equation 3 5 That is, the air-fuel ratio of the collecting section is the sum of the past combustion history of each cylinder multiplied by the weight Cn (for example, 40% for the most recently burned cylinder, 30% before that, etc.). expressed. This model is represented by a block diagram as shown in Fig. 43.

The equation of state is as shown in Equation 36.

Equation 3 6 If the air-fuel ratio of the collecting part is y (k), the output equation can be expressed as shown in Equation 37. x (k-3)

y (k) = [c i c 2 c 3] x (k-2) + C 4 u (k)

x (k-l) number 3 where

ci: 0.05, c2 0.15, c30, c4: 0.50. In the above, since u (k) is not observable, even if an observer is designed from this equation of state, X (k) cannot be observed. Therefore, assuming that the air-fuel ratio before 4TDC (that is, the same cylinder) is in a steady operation state in which the air-fuel ratio does not change rapidly, and X (k + 1) = x (k-3), Equation 38 is obtained.

x (k-2) 0 1 00 x (k-3)

x (k-l) 00 1 0 x (k— 2)

x (k) 000 1 x (k-l)

x (k + l) 1 000 x (k)

x (k—3)

y (k) = (c i c 2 c 3 c 4 I x (k-2)

x (k-l)

x (k) number 38 Here, simulation results are shown for the model obtained as described above. the 4th Fig. 4 shows the case where the air-fuel ratio of the three cylinders is set to 14.7: 1 and the fuel is supplied to only one cylinder at 12.0: 1 for the four-cylinder internal combustion engine. Fig. 45 shows the air-fuel ratio of the collecting part at that time obtained by the above model. In the figure, a step-like output is obtained, but if the response delay of the LAF sensor is further taken into consideration, the sensor output will have a waveform that is smoothed as shown in Fig. 46 as "model output value". Become. In the figure, “The measured value J is the measured value of the LAF sensor output in the same case, but in comparison with this, it has been verified that the above model models the exhaust system of the multi-cylinder internal combustion engine well.

Therefore, it comes to the usual Kalman-Fil-Yu problem of observing X (k) with the state equation and the output equation shown in Equation 39. Solving the Ricatsch equation with the weight matrices Q and R as shown in Equation 40 gives the gain matrix K as shown in Equation 41.

X (k + l) = AX (k) + B u (k) y (k) = CX (k) + Du (k)

Number 39 where

0 1 00

00 1 0

A = 000 1 C = [C i C ₂ C ₃ C 4] B = D = [0]

1 000

X (k) =

1 0 0 0

Q = 0 1 0 0 R = [1] number 4 0

0 0 1 0

0 0 0 1

Number 4 1

When we find A—KC, we get Equation 4 2

0.0022 0.9935 0.0131 one 0.0218

A-K C = 0.0141 0.0423 0.9153 one 0.1411

0.0914 0.2742 0.5485 0.0858 1.0141 0.0423 0.0847 0.1411 Number 4 2 The general observer configuration is as shown in Fig. 47, but since there is no input u (k) in this model, as shown in Fig. 48 And only y (k) is input, and this is expressed by the following equation. y (k)

Equation 43 Here, the observer that receives y (k) as input, that is, the system matrix of the Kalman filter is expressed as Equation 44.

S = number 44

In this model, the weight distribution of the Ricatsch equation When the element of R: the element of Q = 1: 1, the system matrix S of Kalman-Fill is given by Equation 45. 0.0022 0.9935 0.0131 0.0218 0.0436

0.0141 0.0423 0.9153 0.1411 0.2822

s = 0.0914 0.2742 0.5485 0.0858 1.8283

1.0141 0.0423 0.0847 0.1411 -0.2822

0.0000 0.0000 0.0000 1.0000 0.0000

Equation 4 5 Figure 49 shows the combination of the above model and observer. The simulation results are omitted since they are shown in the earlier application, but by this, the air-fuel ratio of each cylinder can be accurately extracted from the air-fuel ratio of the collecting section.

Since the observer was able to estimate the air-fuel ratio of each cylinder from the air-fuel ratio of the collecting section, it was possible to control the air-fuel ratio for each cylinder using a control law such as PID. Specifically, as shown in Fig. 50 in which only the feedback part of the observer in Fig. 36 is extracted, the feedback of the collecting part using the PID control rule from the sensor output (collecting part air-fuel ratio) and the target air-fuel ratio. In addition to calculating the coefficient KLAF, obtain the feedback correction coefficient #nKLAF (n: cylinder) for each cylinder from the observer estimated value # nA / F. The feedback correction coefficient #nKLAF for each cylinder is more specifically the cylinder air-fuel ratio. The feedback correction coefficient for each cylinder #nKLAF is calculated using the PID law so as to eliminate the deviation between the target value obtained by dividing the average value for all cylinders by the previous calculation value and the estimated observer value # nA / F.

As a result, the air-fuel ratio of each cylinder converges to the air-fuel ratio of the collecting portion, and the air-fuel ratio of the collecting portion converges to the target air-fuel ratio. As a result, the air-fuel ratio of all cylinders converges to the target air-fuel ratio. Here, the fuel injection amount #n Tout of each cylinder (specified by the injector opening time) is

#n Tout = Tcyl x # nKLAF xKLAF

Is required. Here, returning to the flow chart of FIG. 39, the sampling of the LAF sensor output will be described. This program is started at TDC.

This will be described below with reference to the flowchart in FIG. First, in S1200, the engine speed Ne, the intake pressure Pb, and the valve timing V / T are read out, and the program proceeds to S1204, S1206, where a timing map for Hi V / T or LoV / T (described later) is prepared. Retrieval is performed, and the process advances to S1208 to sample a sensor output used for an observer operation for Hi or L0 valve timing. Specifically, a timing map is searched from the planned rotation speed Ne and the intake pressure Pb, and one of the above-mentioned 12 buffers is selected by its No., and the sampling number recorded there is recorded. Fig. 51 is an explanatory diagram showing the characteristics of the timing map. As shown, the characteristics are sampled at a faster crank angle as the engine speed Ne is lower or the intake pressure (load) Pb is higher. Is set to select the value. Here, “early” means a value sampled at a position closer to the previous TDC position (in other words, an old value). Conversely, a setting is made to select a crank angle that is slower as the engine speed Ne is higher or the intake pressure Pb is lower, that is, a value sampled at a crank angle closer to the later TDC position (in other words, a new value). .

In other words, as shown in Fig. 38, it is best to sample the LAF sensor output at a position as close as possible to the actual air-fuel ratio inflection point, but the inflection point, for example, the first peak value is Assuming that the reaction time of the sensor is constant, as shown in FIG. 52, the lower the engine speed, the faster the crank angle. Also, it is expected that the higher the load, the higher the exhaust gas E power and exhaust gas volume, and hence the faster the exhaust gas flow rate, and the faster the arrival time at the sensor. For this reason, the sample timing was set as shown in Fig. 51.

Further, regarding the valve timing, an arbitrary value of the engine speed Nel is set to Nel-Lo for the L0 side and Ne-Hi for the Hi side, and the arbitrary value of the intake pressure is set to Pb for the L0 side. 0, and Pbl-Hi for the Hi side, the map characteristics are: Pbl-Lo> Pbl-Hi

Nel-Lo> Nel-Hi And That is, since the opening time of the exhaust valve is earlier than that of Lo V / T in Hi V / T, if the value of the engine speed or the intake pressure is the same, an earlier sampling value should be selected. Is set to the map characteristics.

Then, the process proceeds to S1210 to perform the operation of the observer matrix on HiV / T, and then proceeds to S1212 to perform the same operation on LoV / T. Then, the process proceeds to S1224 to judge the valve timing again, and according to the judgment result, the process proceeds to S12216 and S12218 to select the calculation result and finish.

That is, since the behavior of the air-fuel ratio collecting part changes with the switching of the valve timing, it is necessary to change the observer matrix. However, the estimation of the air-fuel ratio of each cylinder cannot be performed instantaneously, and it takes several operations to complete the calculation of the air-fuel ratio estimation of each cylinder. The calculation using the changed observer matrix is overlapped, and if the valve timing is changed, it can be selected according to the changed valve timing in S1214. I made it. After each cylinder is estimated, as described above, a feedback correction coefficient is determined so as to eliminate the deviation from the target value, and the injection amount is determined.

With this configuration, the detection accuracy of the air-fuel ratio can be improved. That is, as shown in Fig. 53, since sampling is performed at relatively short intervals, the sampled value reflects the sensor output almost exactly, and the values sampled at the relatively short interval are sequentially recorded in the buffer group. In advance, the inflection point of the sensor output is predicted according to the engine speed and the intake pressure (load), and the corresponding value is selected from a group of buffers at a predetermined crank angle. Thereafter, an observer calculation is performed to estimate the air-fuel ratio of each cylinder, and as described in FIG. 50, feedback control of the air-fuel ratio for each cylinder is also possible.

Therefore, as shown in the lower part of FIG. 53, the CPU core 70 can accurately recognize the maximum value and the minimum value of the sensor output. Therefore, with this configuration, when estimating the air-fuel ratio of each cylinder using the above-described observer, a value approximating the behavior of the actual air-fuel ratio can be used, and the estimation accuracy of the observer is improved. The accuracy when performing the cylinder-by-cylinder air-fuel ratio feedback control described with reference to FIG. 50 is also improved. . The details are described in detail in Japanese Patent Application No. 6-243, 277 previously proposed by the present applicant, and further description will be omitted.

The above is the sampling operation performed by the observer on the LAF sensor output (shown as Set 0BSV in Fig. 36), but the STR controller also performs the same sampling operation (shown as Set VSTR in Fig. 36). .

That is, this Set VSTR is also obtained according to the same procedure as that performed with Sel-VOBSV, that is, the procedure shown in the flow chart similar to FIG. Set V0BSV detects the air-fuel ratio at the most convenient timing for the cylinder-by-cylinder air-fuel ratio estimation by the observer (for example, the timing at which the weight coefficient C of the above-mentioned server becomes optimal for the model). The Sel-VSTR is shown in Fig. 51 shown in Set V0BSV so that it is the most convenient timing to operate the STR (for example, the detection timing of the air-fuel ratio most affected by the cylinder in the latest exhaust stroke). The air-fuel ratio is detected using the same map as in the above. Assuming the above, the tenth embodiment will be described with reference to the flow chart of FIG. 35, and the same steps as those of the first embodiment will be performed through steps S110 to S110. Proceed to 1 1 1 2 to detect the sampling of the LAF sensor output by Sel-VSTR, that is, the air-fuel ratio KACT (k). Then, the process proceeds to S111, where a feedback correction coefficient KSTR is calculated in the same manner as in the first embodiment. More specifically, this is performed using the flowchart of FIG. 11 used in the first embodiment.

Then, the process proceeds to S111, S118 to calculate the required fuel injection amount Tcyl (k) and the output fuel injection amount Tout (k), and then proceeds to S112 to set V0BSV. L Sampling of the AF sensor output, that is, the equivalent ratio KACT (k) is detected. Next, proceeding to S 1 1 2 2, the air-fuel ratio # nA / F of each cylinder is estimated via the above-mentioned observer, and proceeding to SI 124, a feedback correction coefficient #nKLAF for each cylinder is calculated, and S 1 1 Proceed to 26 to find the learning value #nKLAFsty from the weighted average value with the previous value, etc., and proceed to S11128 to multiply and correct the output fuel injection amount Tout by the feedback correction coefficient #nKLAF for each cylinder. Then, the output injection amount of the cylinder is set to #n Tout, and the flow proceeds to S110 to correct the intake pipe wall adhesion, and then proceeds to S113 to output.

If the result is negative in S111 or S111, go to S113 and show Calculate the required fuel injection amount Tcyl (k) as shown in (1), proceed to S1136, read the feedback value of the feedback correction coefficient #nKLAFsty for each cylinder, and proceed to S1138 to correct the learning value. # Set to nKLAF. If the fuel cut is determined in S114, the flow proceeds to S116 via S114 to stop the matrix calculation, and the flow proceeds to S114 to provide feedback for each cylinder. The correction coefficient is the previous value. The remaining steps are not different from the first embodiment.

In the tenth embodiment, since the configuration is as described above, the input to the parameter adjuster is synchronized with the combustion cycle while calculating the adaptive parameters as in the first embodiment. The computational load on the parameter adjustment mechanism is greatly reduced, enabling the use of an adaptive controller for the actual machine while ensuring controllability, and at the same time, reducing inter-cylinder variability.

Also, as in the first embodiment, the average value of the air-fuel ratio KACT or the average value of the adaptive parameter over one combustion cycle for all cylinders is obtained and input to the parameter adjusting mechanism, and the STR controller Since the average value of the output of the cylinder is also obtained, it is not greatly affected by the combustion state of the specific cylinder.

Incidentally, in the tenth embodiment, the adaptive parameter overnight or the average value of the KSTR may be obtained similarly to the second embodiment, or the air-fuel ratio KACT and the adaptive parameter zero hat may be obtained. It goes without saying that the average value may be obtained together. Also, the target air-fuel ratio KCMD (k) may be the same value for all cylinders.

Also, in the tenth embodiment, the second, third, fourth, fifth, sixth, and seventh embodiments are described. The descriptions of the embodiments, the eighth embodiment and the ninth embodiment are all appropriate.

FIG. 54 and FIG. 55 are a flow chart and a block diagram showing a first embodiment of the device according to the present application.

In the case of the eleventh embodiment, as shown in FIG. 55, the STR controller and the parameter adjustment mechanism were inserted in series in the fuel injection amount calculation system. That is, similarly to the first embodiment, the basic fuel injection amount T im is multiplied by the target air-fuel ratio correction coefficient KCMDM0 and the various correction coefficients KT0TAL to obtain the required fuel injection amount T cyKk), and then the corrected request Fuel injection Enter the quantity Tcyl (k) into the STR controller.

On the other hand, the average value KACT AVE or 0 hat AVE is obtained from the detected exhaust system air-fuel ratio in the same manner as in the first embodiment, and the STR controller dynamically determines the required fuel injection amount T cyl (k). Correction is performed and the corrected fuel injection amount G fuel-str (k) is calculated.

At the same time, the feedback correction coefficient KLAF of the collecting section is obtained from the detected air-fuel ratio of the exhaust system using the PID control law and multiplied by the required fuel injection amount TcyKk) to correct the corrected fuel injection amount G f ue 1 -KLAF. Calculate (k).

In FIG. 55, the STR controller adjusts the output fuel fuel adaptively so that the actual intake fuel amount (more precisely, the estimated intake fuel amount) G fuel (k) matches the target fuel amount Tcyl (k). Calculate the quantity G fuel-str (k) and supply it to the internal combustion engine as the output fuel injection quantity Tout (k). Incidentally, the correction of the wall adhesion in the virtual blunt is described in detail in Japanese Patent Application No. Hei 4-200331 (Japanese Patent Application Laid-Open No. Hei 6-176681) previously proposed by the present applicant. Since the gist of this invention is not there, the explanation is omitted.

Here, the actual intake fuel amount G fuel (k) can be obtained by dividing the detected air amount by the detected air-fuel ratio, but in the case of the embodiment, the air amount detector (air flow meter ), The target intake fuel amount (required injection amount) T cyl O is multiplied by the detected air-fuel ratio. As a result, the actual intake fuel amount can be obtained in a manner equivalent to detecting and obtaining the air amount. As described above, in this control, the target air-fuel ratio and the detected air-fuel ratio are actually expressed as equivalent ratios.

If the target air-fuel ratio is not the stoichiometric air-fuel ratio, the calculated value is further divided by the target air-fuel ratio to obtain the actual intake fuel amount. That is, when the target air-fuel ratio is the stoichiometric air-fuel ratio, the actual intake fuel amount is

Actual intake fuel amount = demanded injection amount (target intake fuel amount) X detected air-fuel ratio (equivalent ratio). When the target air-fuel ratio is other than the stoichiometric air-fuel ratio,

Actual intake fuel amount = (required injection amount (target intake fuel amount) X detected air-fuel ratio (equivalent ratio)) Target air-fuel ratio (equivalent ratio)

Ask for.

The above will be described with reference to the flow chart of FIG. 54.The same steps as those in the previous embodiment are performed, and the process proceeds to S 13 18 through S 13 00 to S 13 18 to proceed to S 13 18. Air fuel Average value of ratio KACTAVE and adaptive parameter 6> average value of hat 0 hat -Calculate -AVE.

Subsequently, the flow proceeds to S132 via S13320 to S1322, and determines the instability of the adaptive control system (STR controller) as in the first embodiment.

FIG. 56 is a subroutine 'flow' chart showing the operation.

Referring to the figure, first, in S 1400, the stability of the STR control system is determined using each element of the adaptive parameter 0 hat.

Specifically, the fuel injection amount Gfuel-STR (k) calculated by the STR controller is calculated as in Equation 46.

Tout-str (z)) =

+ raZ- '+ rsZ- ³ )

xGfuel-strCz " ¹ )} / b. · · · Equation 4 6 Here, assuming that the adhesion correction is correct, the transfer function of the virtual blunt is as shown in Equation 4 7.

Gfuel (z- ¹ ) = z- ³ Gfuel-str (z- ') * ... Transfer from Tcyl (k) to injection quantity Gfuel-STR (k) from Equation 4 7 and Equation 4 6 The number looks like the number 4 8.

Gfuel-strCz ^-1 ) 1

z ³

TcyKz " ¹ ) boz ³ + riz ² + r ₂ z + r ₃ + So

· 'Number 4 8

^{'.' (b + s.z- 3} + ηζ -. '+ r 2 z- 2 + r3Z- 3) Gfuel-str (z- 1) = Tcyl (z- 1) Here, b 0 is the gain Since it is a scalar quantity to be determined, it cannot be 0 or negative, so the denominator function f (z) = b OZ ³ + rl Z ² + r 2 Z of the transfer function of Equation 4 8 + R3 + S0 is one of the numbers shown in FIG. Therefore, it is necessary to determine whether or not the real root is within the unit circle, that is, to determine whether or not f (−1) <0 or f (1)> 0 as shown in FIG. For example, if the result is affirmative, the real root is within the unit circle, so it can be easily determined whether the system is stable or not.

Then, in S144, it is determined from the above whether or not the STR controller system is unstable. If the determination is affirmative, the process proceeds to S144, and the adaptive parameter overnight hat is returned to the initial value. As a result, the stability of the system can be restored. Then, the process proceeds to S 14 06 to correct the gain matrix Γ. Since the gain matrix Γ determines the convergence speed, this correction is performed so as to slow down the convergence speed, and the system stability can be restored similarly. Then, proceed to S 148, as shown in the figure, using the correction coefficient KLAF (k) based on the PID control law as the feedback correction coefficient, using the corrected fuel injection amount G fuel-KLAF, and adding the addition term TT0TAL to it. To determine the output fuel injection amount T out (k).

If it is determined in S1402 that the STR controller system is not unstable, the process proceeds to S141σ, and as shown in the figure, a correction coefficient KSTR (k) according to the adaptive control law is used as a feedback correction coefficient. Use the corrected fuel injection amount G fuel-str (k) using, and add the addition term TT0TAL to determine the output fuel injection amount Tout (k).

Returning to the flow chart of FIG. 54, the program then proceeds to 1326 to output the output fuel injection amount and finish. In the case of the first embodiment, the calculation of the average value such as the air-fuel ratio is different from the previous embodiment, and is not limited to the predetermined crank angle of the specific cylinder, but is performed at the predetermined crank angle of each cylinder. May be. Note that the remaining configuration is not different from the previous embodiment.

In the eleventh embodiment, the configuration is as described above, and as in the first embodiment, the input to the parameter adjustment mechanism may be synchronized with the combustion cycle while calculating the adaptive parameter. The computational load of the parameter adjustment mechanism is greatly reduced, and it is possible to use an adaptive controller for the actual machine while ensuring controllability. In addition, the controllability can be improved by reducing the dead time.

Also in the eleventh embodiment, the average value of the control amounts of all the cylinders is determined to obtain the parameter. Since it is input to the evening adjustment mechanism, it is not significantly affected by the combustion state of the specific cylinder.

In the first to eleventh embodiments, the simple average value is shown as the average value. However, the present invention is not limited to this, and may be a weighted average value, a moving average value, a weighted moving average value, or the like. In addition, although the average value during one combustion cycle in which the input to the parameter adjustment mechanism is performed in synchronization is obtained, the average value before two combustion cycles may be obtained, or less than one combustion cycle, for example, two Alternatively, an average value between 3 TDCs may be obtained.

As described above, it is natural that it is only necessary to separately provide the Se-VOBSV and the Set VSTR and detect the optimal air-fuel ratio for each, but depending on the characteristics of the engine and the layout of the exhaust system, the Se-VOBSV and Since the Se-VSTR shows almost the same detected air-fuel ratio in almost all operating regions, in such a case, these sampling functions are unified to detect the air-fuel ratio, and the output is used for both the observer and the STR. May be used as input. For example, only the Set V0BSV shown in FIG. 36 may be used, and the output may be used for the observer and the STR. Although the equivalent ratio is actually used as the air-fuel ratio in the first embodiment and the like, it goes without saying that the air-fuel ratio and the equivalent ratio may be separately determined. Further, the feedback correction coefficient KSTR. # NKLAF.KLAF is obtained as a multiplication term, but may be obtained as an addition value.

In the above description, the STR is taken as an example of the adaptive controller, but MRACS (model reference adaptive control) may be used.

In the above description, the output of a single air-fuel ratio sensor provided in the exhaust system converging section is used, but the present invention is not limited to this, and the air-fuel ratio detected by providing the air-fuel ratio sensor for each cylinder is used for each cylinder. Fuel ratio feedback control may be performed. Industrial applicability

According to the present invention, a fuel injection amount control means for controlling a fuel injection amount of a multi-cylinder internal combustion engine, an adaptive controller for adaptively matching the fuel injection amount to a target value as an operation amount, and the adaptive control An adaptive parameter adjustment mechanism for calculating an adaptive parameter used in the fuel injector, the fuel injection control device for a multi-cylinder internal combustion engine comprising: -The input to the evening adjustment mechanism is performed in synchronization with the specific combustion cycle of the internal combustion engine, and the adaptive parameter adjustment mechanism determines whether at least one of the air-fuel ratio and the in-cylinder fuel amount in the fuel control cycle of the internal combustion engine. Since the calculation of the adaptive parameter is performed on the basis of this, the amount of matrix operation can be reduced and the load on the in-vehicle view can be reduced, and the calculation can be completed within one TDC even in the usual in-vehicle view. At the same time, when adaptively calculating the feedback correction coefficient using an adaptive control algorithm having a parameter adjustment mechanism using Landau's adjustment law, a parameter adjustment mechanism must be used for each fuel control cycle for each TDC. Even when operating, the input used by the adaptive parameter adjustment mechanism is set to the value for each combustion cycle, thereby improving control performance, reducing dead time, and calculating the number of internal variables. Can be reduced.

Further, since the input to the adaptive parameter adjusting mechanism is configured to be performed in synchronization with a fuel control cycle of a specific cylinder of the internal combustion engine, in addition to the above-described operation or effect, the adaptive parameter The evening adjustment mechanism can be operated in synchronization with the fuel control cycle of the specific cylinder, the operation time can be further reduced, and the adaptive control can be continued even at high rotation speed.

Further, since the adaptive controller is configured to operate in synchronization with the fuel control cycle of the internal combustion engine, the adaptive controller receives the adaptive parameter and calculates the feedback correction coefficient regardless of the calculation cycle of the adaptive parameter. The adaptive controller is configured to operate every fuel control cycle such as TDC, and even if the number of calculations of the parameter adjustment mechanism is reduced to one in the combustion cycle, the fuel Since the feedback correction coefficient is calculated for each fuel control cycle, feedback control of the air-fuel ratio can always be optimally performed.

Furthermore, air-fuel ratio detection means for detecting the exhaust air-fuel ratio of the internal combustion engine, fuel injection quantity control means for controlling the fuel injection amount of the internal combustion engine for each fuel control cycle, and at least the detected exhaust air-fuel ratio based on the detected exhaust air-fuel ratio A fuel injection control device for an internal combustion engine, comprising: a controller of a recurrence type in which the fuel injection amount is made to coincide with a target value as an operation amount by using a controller of a gasification type. The controller is configured to operate in a predetermined operating state in synchronization with a cycle longer than the fuel control cycle. Thus, the load on the on-board computer can be reduced by reducing the amount of calculation added by the recurrence-type controller, and the calculation can be completed within one TDC even with a conventional on-board computer.

Here, the “predetermined operating state” specifically means a time when the internal combustion engine is rotating at a high speed. That is, the time that can be used for one operation is reduced at the time of high rotation, but adaptive control can be continued even at the time of high rotation by configuring as described above. On the other hand, at the time of high speed, since the variation of the adaptive parameter and the detected air-fuel ratio are relatively small, the controllability does not deteriorate even with the above configuration. Therefore, the adaptive control can be continued even in the running down state where the calculation time is short, such as at the time of high rotation, and good air-fuel ratio controllability can be secured.

Further, since the controller of the recurrence type is configured as an adaptive controller, the feedback correction coefficient is adaptively adjusted by using an adaptive control algorithm having a parameter adjustment mechanism using an adjustment rule such as Landau. When calculating, the load on the onboard computer can be reduced by reducing the amount of computation by the adaptive controller, which has a long operation time, especially among the recursive type controllers, and even an ordinary onboard computer can use 1 TDC. The operation can be completed within.

Further, the adaptive controller includes an adaptive parameter adjusting mechanism for calculating an adaptive parameter used therein, and at least the detected exhaust air-fuel ratio is input to the adaptive parameter adjusting mechanism, and the adaptive parameter adjusting mechanism is controlled by a predetermined parameter. Since the operation is performed in synchronization with the cycle longer than the fuel control cycle in the operating state, in addition to the above-described effects and effects, the adaptive parameter adjustment mechanism is used to control the fuel control cycle of the specific cylinder. The calculation can be performed in synchronization with the rotation speed, the calculation time can be further reduced, and the adaptive control can be continued even at a high rotation speed. Here, the cycle longer than the fuel control cycle was configured, more specifically, as described above, to be a value corresponding to an integral multiple of the combustion cycle.

Further, the detected air-fuel ratio input to the controller of the recurrence type is configured to be a value based on a plurality of values detected in a cycle shorter than the operation cycle of the controller of the recurrence type. Therefore, in addition to the above-described effects and effects, for example, by operating the plurality of values as an average value of a plurality of detected values, it is possible to always operate at a predetermined crank angle of a specific cylinder. Also, there is no inconvenience that strongly reflects only the combustion state of the specific cylinder.

Further, the detected air-fuel ratio input by the adaptive parameter adjustment mechanism is configured to be a value based on a plurality of values detected in a cycle shorter than the operation cycle of the adaptive parameter adjustment mechanism. By using the plurality of values as the average value of the plurality of detected values, even when the cylinder always operates at a predetermined crank angle of a specific cylinder, there is no inconvenience that only reflects the combustion state of the specific cylinder.

Further, a fuel injection amount control means for controlling a fuel injection amount of the internal combustion engine, an adaptive controller which operates so that the fuel injection amount becomes an operation amount so as to match a target value, and an adaptation used in the adaptive controller A fuel injection control device for an internal combustion engine, comprising: an adaptive parameter overnight adjusting mechanism for calculating a parameter; and operating state detecting means for detecting an operating state of the internal combustion engine, comprising: Since the control cycle of at least one of the adaptive controller and the adaptive parameter adjusting mechanism is configured to be changed, the adaptive control is continued even in an operation state in which the calculation load is reduced and the calculation time is reduced, such as at high rotation. And good controllability can be obtained.

Furthermore, since the control cycle of the adaptive parameter adjustment mechanism is set to be equal to or longer than the control cycle of the adaptive controller, the calculation load is further reduced, and the calculation time during high rotation and the like is reduced. Adaptive control can be more easily inherited even in an operating state where the vehicle is running, and good controllability can be obtained.

Furthermore, since the control cycle of the adaptive parameter adjustment mechanism is configured to be an integral multiple of the control cycle of the adaptive controller, the operation of the adaptive parameter adjustment mechanism, which requires a particularly long time, is calculated by the control cycle of the STR controller. This is executed once every two or more times, which effectively reduces the amount of computation while ensuring controllability, and results in a relative increase in the number of computations by the STR controller that actually performs the fuel control. In addition, adaptive control can be continued while maintaining good controllability even in an operation state in which the calculation time is reduced, such as at high rotations, and good controllability can be obtained.

Further, since the control cycle of at least one of the adaptive controller and the adaptive parameter adjustment mechanism is changed at a cycle that is an integral multiple of the fuel control cycle, the operation amount obtained by the adaptive controller is changed to an integer of the fuel control cycle. By using over twice as long, the operation load can be further reduced and the operation time can be reduced, such as during high-speed operation. Can easily succeed to adaptive control and obtain good controllability o

Furthermore, since the operation state is configured to be at least the engine speed, it is possible to reliably detect an operation downtime in which the operation time is reduced, such as at high engine speed, thereby reducing the operation load. Therefore, even in such an operating state, it is possible to continue adaptive control and obtain good controllability.

Further, an air-fuel ratio detecting means provided in an exhaust system of the internal combustion engine and detecting an exhaust air-fuel ratio; an operating state detecting means for detecting an operating state of the internal combustion engine including at least an engine speed and an engine load; A fuel injection amount determining means for determining a fuel injection amount of each cylinder at a predetermined crank angle of each cylinder based on at least the detected operating state of the internal combustion engine; and A fuel injection means for injecting fuel into individual cylinders based on the information, an adaptive controller and an adaptive parameter adjusting mechanism for estimating an adaptive parameter, and the adaptive controller outputs an output of the air-fuel ratio detecting means. Fuel injection control for an internal combustion engine, comprising: feedback means for correcting the fuel injection amount so as to match a control amount obtained based on at least the target value. In location, since the adaptive parameter adjusting mechanism and the adaptive controller is configured to operate independently of the operating cycle, o that it is possible to obtain the same advantages as the

The first embodiment to the eleventh embodiment can obtain the above-described functions and effects in the configuration of each embodiment. However, in the configuration in which many of these embodiments are combined, Good controllability in the fuel control device of the internal combustion engine, in other words, more accurate control of the exhaust gas air-twist ratio becomes possible. It is needless to say that the most effective operation and effect can be obtained by configuring all the embodiments in consideration of the operating state of the engine.

Further, the first embodiment to the eleventh embodiment can be classified into several types according to their operations and effects.

The first embodiment relates to the application of an adaptive controller to a fuel control device of an internal combustion engine.

In addition, the function and effect of improving the controllability (computation accuracy) of the adaptive controller and increasing the computation processing capacity can be obtained. In addition, the bias of the air twist ratio for each cylinder due to the specific operating state of the engine has been eliminated. Actions and effects that can be obtained. In addition, an adaptive controller and P

The operation and effect of preventing deterioration of controllability when switching the ID controller can be obtained. The seventh embodiment is equivalent to an actual application example of the first embodiment. In the seventh embodiment, the operation and effect of ensuring the excellent controllability of the adaptive controller can be obtained in all operating states.

The second embodiment and the third embodiment relate to the operation method of the adaptive controller. The second embodiment improves the controllability (computation accuracy) of the adaptive controller, expands the computation processing capability, and increases the control characteristics by appropriately setting the gain matrix の of the adaptive controller according to the operating state of the engine. The function and effect that the setting of the camera becomes easy can be obtained. In the third embodiment, the gain matrix の of the adaptive controller is set from the behavior of the blunt output, and the operation and effect of improving the controllability (calculation accuracy) of the adaptive controller and expanding the calculation processing capability are obtained. Can be

The fourth embodiment relates to processing of an input signal to an adaptive controller. The fourth embodiment has a configuration in which a dead band is provided in the detected air-twist ratio, which is the input to the adaptive controller, to prevent the controllability (calculation accuracy) of the adaptive controller from deteriorating due to a small change in the detected air-twist ratio. The effect of stopping is obtained.

The fifth embodiment and the sixth embodiment relate to the calculation method of the adaptive controller, particularly to the changing speed of the adaptive parameter. In the fifth embodiment, an operation and an effect of improving the control stability of the adaptive controller can be obtained by providing a configuration in which a change speed of the adaptive parameter used in the adaptive controller is limited. In the fifth embodiment, the operation and effect of improving the controllability (calculation accuracy) of the adaptive controller can be obtained by a configuration in which the change speed of the adaptive parameter used in the adaptive controller is calculated and stabilized.

The eighth and ninth embodiments relate to a calculation method of the adaptive controller, particularly to a calculation method of the adaptive controller in a specific operation state. In the eighth and ninth embodiments, the calculation method of the adaptive controller is changed in accordance with the specific operating state, whereby the bias of the air-twist ratio for each cylinder due to the specific operating state of the adaptive controller is adjusted. Can be eliminated.

The tenth embodiment relates to a method for calculating the fuel injection amount by the adaptive controller and the cylinder-by-cylinder air twist ratio control means. The tenth embodiment eliminates the deviation of the air twist ratio for each cylinder With the configuration in which the air-twist ratio control means by the adaptive controller is added to the means, the bias of the air-twist ratio for each cylinder can be eliminated, and the action and effect of improving the controllability (calculation accuracy) of the adaptive controller can be obtained. In addition, the configuration that optimizes the detection timing of the air-twist ratio according to the operating state of the engine improves the accuracy (detection) of the detection and calculation of the air-twist ratio for each cylinder and the controllability (operation accuracy) of the adaptive controller. Can be obtained.

The eleventh embodiment relates to a method of connecting an adaptive controller to a plant.

This corresponds to a modification of the first embodiment and the third embodiment. In the eleventh embodiment, the operation and effect of improving the controllability (calculation accuracy) of the adaptive controller can be obtained by the configuration of directly calculating the fuel injection amount. In addition, by adopting a configuration in which the stability of the adaptive controller is determined from the adaptive parameters used in the adaptive controller, the operation and effect of improving the control stability of the adaptive controller and expanding the arithmetic processing capability can be obtained.

The functions and effects described in the respective embodiments are improved by the configuration in which the types of the embodiments described above are combined with the embodiments belonging to the same type. In addition, even when the types of some embodiments are combined, the operation and effect described in each embodiment are synergistically improved, and good controllability in the fuel control device of the internal combustion engine, in other words, more accurate exhaust gas space is obtained. As described above, the twist ratio can be controlled.

If the first and seventh embodiments are used in combination with the second and third embodiments, the controllability (operation accuracy) of the adaptive controller is improved and the operation processing capability is expanded. , Get the effect.

When the first embodiment, the seventh embodiment, and the fourth embodiment are used in combination, it is possible to obtain an action and an effect of improving the controllability (operation accuracy) of the adaptive controller and expanding the operation processing capability.

If the first and seventh embodiments are used in combination with the fifth and sixth embodiments, the effect of improving the controllability (calculation accuracy) of the adaptive controller and expanding the calculation processing capability is obtained. , Get the effect.

If the first embodiment, the seventh embodiment, the eighth embodiment, and the ninth embodiment are used in combination, the bias of the air-twist ratio for each cylinder due to the specific operation state of the adaptive controller can be eliminated. Improvement of controllability (computation accuracy) of the adaptive controller and expansion of computational processing capacity Action and effect.

If the first embodiment, the seventh embodiment, and the tenth embodiment are used in combination, the bias of the air-twist ratio for each cylinder can be eliminated, and the controllability (calculation accuracy) of the adaptive controller and the calculation processing can be improved. The effect of expanding capacity is obtained.

If the first embodiment, the seventh embodiment, and the first embodiment are used in combination, the control stability of the adaptive controller is improved, the controllability (calculation accuracy) of the adaptive controller is improved, and the processing capacity is improved. The effect of expanding is obtained. In particular, as described above, it is effective to determine the stability of the adaptive parameters used in the adaptive controller according to the first embodiment in each embodiment.

If the second embodiment, the third embodiment, and the fourth embodiment are used in combination, it is possible to obtain the action and effect of improving the controllability (operation accuracy) of the adaptive controller and expanding the operation processing capability.

If the second and third embodiments are used in combination with the fifth and sixth embodiments, the controllability (operation accuracy) of the adaptive controller is improved and the operation processing capability is expanded. , Get the effect.

If the second and third embodiments are used in combination with the eighth and ninth embodiments, the bias of the air-twist ratio for each cylinder due to the specific operation state of the adaptive controller can be eliminated. The effect of improving the controllability (calculation accuracy) of the adaptive controller and expanding the calculation processing capacity can be obtained.

If the second and third embodiments are used in combination with the tenth embodiment, the bias of the air-twist ratio for each cylinder can be eliminated, so that the controllability (calculation accuracy) of the adaptive controller and the calculation processing can be improved. The effect of expanding capacity is obtained.

When the second embodiment, the third embodiment, and the first embodiment are used in combination, the operation and effect of improving the controllability (operation accuracy) of the adaptive controller and expanding the operation processing capability can be obtained. In addition, by adopting a configuration in which the stability of the adaptive controller is determined from the adaptive parameters used in the adaptive controller in the first embodiment, the operation and effect of improving the control stability of the adaptive controller and expanding the arithmetic processing capability can be achieved. can get.

If the fourth embodiment, the fifth embodiment, and the sixth embodiment are used in combination, the effect of improving the controllability (computation accuracy) of the adaptive controller and increasing the computation processing capability, The effect can be obtained.

If the fourth embodiment, the eighth embodiment, and the ninth embodiment are used in combination, the bias of the air-twist ratio for each cylinder caused by the specific operation state of the adaptive controller can be eliminated, and the adaptive controller can be controlled. The operation and effect of improving the performance (operation accuracy) and expanding the operation processing capacity can be obtained.

If the fourth embodiment and the tenth embodiment are used in combination, the bias of the air-twist ratio for each cylinder can be eliminated, and the controllability (computation accuracy) of the adaptive controller can be improved and the computation processing capacity can be increased. The effect can be obtained.

If the fourth embodiment and the first embodiment are used in combination, the bias of the air-twist ratio for each cylinder can be eliminated, and the controllability (computation accuracy) of the adaptive controller can be improved and the computation processing capacity can be increased. The effect can be obtained. In addition, by adopting a configuration in which the stability of the adaptive controller is determined from the adaptive parameters used in the adaptive controller in the eleventh embodiment, it is possible to improve the control stability of the adaptive controller and expand the arithmetic processing capability. Action and effect can be obtained. By using the fifth and sixth embodiments in combination with the eighth and ninth embodiments, the bias of the air-twist ratio for each cylinder due to the specific operating state of the adaptive controller is also eliminated. As a result, it is possible to obtain the function and effect of improving the controllability (calculation accuracy) of the adaptive controller and expanding the processing capacity.

If the fifth and sixth embodiments are used in combination with the tenth embodiment, the bias of the air-twist ratio for each cylinder can be eliminated, and the controllability (computation accuracy) of the adaptive controller and the computation processing can be improved. The effect of expanding capacity is obtained.

If the fifth embodiment, the sixth embodiment, and the first embodiment are used in combination, it is possible to obtain the effect of improving the controllability (operation accuracy) of the adaptive controller and expanding the operation processing capability. In addition, by adopting a configuration in which the stability of the adaptive controller is determined from the adaptive parameters used in the adaptive controller in the first embodiment, the operation and effect of improving the control stability of the adaptive controller and expanding the arithmetic processing capability can be achieved. can get.

If the eighth and ninth embodiments are used in combination with the tenth embodiment, the bias of the air-twist ratio for each cylinder can be eliminated, and the controllability (calculation accuracy) of the adaptive controller and the calculation processing can be improved. The effect of expanding capacity is obtained.

Use by combining the eighth and ninth embodiments with the eleventh embodiment This eliminates the bias of the air-twist ratio for each cylinder due to the specific operation state of the adaptive controller, and improves the controllability (calculation accuracy) of the adaptive controller and expands the processing capacity. In addition, the configuration of determining the stability of the adaptive controller from the adaptive parameters used in the adaptive controller according to the eleventh embodiment improves the control stability of the adaptive controller and increases the operation processing capability. The effect can be obtained.

If the tenth embodiment and the eleventh embodiment are used in combination, the bias of the air-twist ratio for each cylinder can be eliminated, and the controllability (computation accuracy) of the adaptive controller and the computation processing capacity can be increased. Action and effect can be obtained. In addition, by adopting a configuration in which the stability of the adaptive controller is determined from the adaptive parameters used in the adaptive controller in the eleventh embodiment, the operation and effect of improving the control stability of the adaptive controller and expanding the arithmetic processing capability are improved. can get.

Claims

The scope of the claims

1.

a. fuel injection amount control means for controlling the fuel injection amount of the multi-cylinder internal combustion engine;

an adaptive controller that adaptively matches the fuel injection amount to a target value as an operation amount; and

c adaptive parameter adjustment mechanism for calculating an adaptive parameter used in the adaptive controller,

In the fuel injection control device for a multi-cylinder internal combustion engine provided with, the input to the adaptive parameter adjustment mechanism is performed in synchronization with a specific combustion cycle of the internal combustion engine, and the adaptive parameter adjustment mechanism is A fuel injection control device for an internal combustion engine, which performs a calculation of an adaptive parameter based on at least one of an air-fuel ratio and a fuel amount in a fuel control cycle of the internal combustion engine.

2. The fuel injection control device for an internal combustion engine according to claim 1, wherein the input to the adaptive parameter overnight adjustment mechanism is performed in synchronization with a fuel control cycle of a specific cylinder of the internal combustion engine. .

3. The fuel injection control device for an internal combustion engine according to claim 1, wherein the adaptive controller is operated in synchronization with a fuel control cycle of the internal combustion engine.

Four .

a. air-fuel ratio detecting means for detecting an exhaust air-fuel ratio of the internal combustion engine;

b. a fuel injection amount control means for controlling the fuel injection amount of the internal combustion engine for each fuel control cycle;

and

c. a recurring-type controller that uses the recurring-type controller based on at least the detected exhaust air-fuel ratio to match the fuel injection amount to the target value as the manipulated variable. In the fuel injection control device for an engine, the controller of the recurrence type is specified. The fuel injection control device for an internal combustion engine, wherein the fuel injection control device is operated in synchronization with a cycle longer than the fuel control cycle.

5. The fuel injection control device for an internal combustion engine according to claim 4, wherein the controller of the recurrence type is an adaptive controller.

6. The adaptive controller includes an adaptive parameter adjustment mechanism that calculates an adaptive parameter used therein, and inputs at least the detected exhaust air-fuel ratio to the adaptive parameter adjustment mechanism, and controls the adaptive parameter adjustment mechanism. 6. The fuel injection control device for an internal combustion engine according to claim 5, wherein the fuel injection control device is operated in synchronization with a cycle longer than the fuel control cycle in a predetermined operation state.

7. The fuel injection control device for an internal combustion engine according to claim 4, wherein the period longer than the fuel control cycle is a value corresponding to an integral multiple of a combustion cycle.

8. The detected air-fuel ratio input by the adaptive parameter adjustment mechanism is a value based on a plurality of values detected in a cycle shorter than an operation cycle of the adaptive parameter overnight adjustment mechanism. 7. The fuel injection control device for an internal combustion engine according to claim 6.

9. The detected air-fuel ratio input to the recurrence type controller is shorter than the operation cycle of the recurrence type controller 'and is a value based on a plurality of values detected in the cycle. Fuel injection control for an internal combustion engine according to any one of claims 4 to 8, characterized in that

Ten .

a. fuel injection amount control means for controlling the fuel injection amount of the internal combustion engine;

b. an adaptive controller that operates so that the fuel injection amount is equal to a target value as an operation amount; and

C. an adaptive parameter adjusting mechanism for calculating an adaptive parameter used in the adaptive controller;

In the fuel injection control device for an internal combustion engine comprising

d. operating state detecting means for detecting an operating state of the internal combustion engine;

And a control cycle of at least one of the adaptive controller and the adaptive parameter adjustment mechanism is changed in accordance with the detected operating state.

11. The fuel injection control device according to claim 10, wherein a control cycle of the adaptive parameter adjustment mechanism is equal to or longer than a control cycle of the adaptive controller. .

12. The fuel injection control device for an internal combustion engine according to claim 10, wherein a control cycle of said adaptive parameter adjustment mechanism is set to an integral multiple of a control cycle of said adaptive controller.

13. The method according to claim 10, wherein the control cycle of at least one of the adaptive controller and the adaptive parameter adjusting mechanism is changed at a cycle that is an integral multiple of a fuel control cycle. The fuel injection control device for an engine according to any one of the above.

14. The fuel injection control device for an internal combustion engine according to any one of claims 10 to 13, wherein the operation state is at least an engine speed.

1 5.

an air-fuel ratio detecting means provided in an exhaust system of the internal combustion engine and detecting an exhaust air-fuel ratio; b. operating state detecting means for detecting an operating state of the internal combustion engine including at least an engine speed and an engine load. ,

c. Individual cylinder fuel based at least on the detected operating condition of the internal combustion engine Fuel injection amount determining means for determining an injection amount at a predetermined crank angle of each of the cylinders;

d. fuel injection means for injecting fuel into each cylinder based on the determined fuel injection amount;

e. an adaptive controller and an adaptive parameter adjusting mechanism for estimating an adaptive parameter, and the adaptive controller matches a control amount obtained at least based on an output of the air-fuel ratio detection unit with a target value, Feedback means for correcting the fuel injection amount;

A fuel injection control device for an internal combustion engine, comprising: the adaptive parameter adjustment mechanism and the adaptive controller operating in independent operation cycles.