JP2005083205A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine capable of completing air-fuel ratio learning early. <P>SOLUTION: The control device is provided with a fuel cut-off part 18a for stopping fuel supply to an engine 1 when predetermined fuel cut-off conditions are satisfied; an air-fuel ratio control part 18b for controlling an air-fuel ratio to the rich side according to the stored oxygen quantity of an exhaust purifying catalyst 19 at the return from fuel cut-off operation; a throttle valve 9 for regulating the quantity of air taken into the engine 1; and an ignition control part 18c for controlling ignition in the engine 1. In the control device, when the fuel cut-off conditions are satisfied before air-fuel ratio learning is completed, ignition is stopped without stopping fuel supply, and the quantity of air taken into the engine 1 is reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control device for an internal combustion engine.

A fuel injection control device that sets the target air-fuel ratio to the rich side until the amount of oxygen stored in the three-way catalyst reaches a predetermined appropriate value at the time of transition from fuel cut operation to air-fuel ratio feedback control is disclosed in the following patent document 1.
JP-A-8-193537 (page 3-6, FIG. 1)

  On the other hand, since the air-fuel ratio learning in the air-fuel ratio feedback control is permitted during the stoichiometric control and prohibited during the rich control, the air-fuel ratio learning cannot be performed during execution of the rich control when the fuel cut is restored. Therefore, in the fuel injection control device, the air-fuel ratio learning cannot be started early after the fuel cut is restored, and the completion of the air-fuel ratio learning is delayed.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a control device for an internal combustion engine that can complete air-fuel ratio learning at an early stage.

  The control apparatus for an internal combustion engine according to the present invention stops the fuel supply to the internal combustion engine when a predetermined fuel supply stop condition is satisfied, and sets the stored oxygen amount of the exhaust purification catalyst when returning from the fuel stop operation. Accordingly, in the control device for an internal combustion engine that controls the air-fuel ratio to the rich side, when the fuel supply stop condition is satisfied when the air-fuel ratio learning is not completed, the fuel supply to the internal combustion engine is not stopped, Ignition in an internal combustion engine is stopped.

  According to the control device for an internal combustion engine according to the present invention, when the fuel supply stop condition is satisfied when the air-fuel ratio learning is not completed, the fuel is supplied in a state where the ignition is stopped. The burned fuel is not burned in the combustion chamber but burned in the exhaust purification catalyst. Thereby, the amount of oxygen stored in the exhaust purification catalyst is reduced, and the rich control time at the time of shifting to the air-fuel ratio feedback control is shortened. Therefore, it becomes possible to start stoichiometric control at an early stage.

  The control apparatus for an internal combustion engine according to the present invention stops the fuel supply to the internal combustion engine when a predetermined fuel supply stop condition is satisfied, and sets the stored oxygen amount of the exhaust purification catalyst when returning from the fuel stop operation. Accordingly, in the control device for an internal combustion engine that controls the air-fuel ratio to the rich side, if the fuel supply stop condition is satisfied when the air-fuel ratio learning is not completed, the amount of air drawn into the internal combustion engine is reduced. It is characterized by that.

  According to the control apparatus for an internal combustion engine according to the present invention, when the air-fuel ratio learning is not completed, the amount of air taken into the internal combustion engine during the fuel stop operation is reduced. Therefore, the amount of oxygen stored in the exhaust purification catalyst is reduced, and the rich control time at the time of fuel cut return is shortened. Therefore, it becomes possible to start stoichiometric control at an early stage.

  Here, when the fuel supply stop condition is satisfied when the air-fuel ratio learning is not completed, it is preferable to stop the ignition in the internal combustion engine without stopping the fuel supply to the internal combustion engine.

  In this way, the supplied fuel is burned together with oxygen in the exhaust purification catalyst without being burned in the combustion chamber, so that the amount of oxygen stored in the exhaust purification catalyst can be further reduced. At this time, since the amount of air taken into the internal combustion engine is reduced, the amount of fuel to be injected can be reduced.

  The control apparatus for an internal combustion engine according to the present invention stops the fuel supply to the internal combustion engine when a predetermined fuel supply stop condition is satisfied, and sets the stored oxygen amount of the exhaust purification catalyst when returning from the fuel stop operation. Accordingly, in the control device for the internal combustion engine that controls the air-fuel ratio to the rich side, if the fuel supply stop condition is satisfied when the purge gas concentration learning is not completed, the amount of air drawn into the internal combustion engine is reduced. In addition, the ignition in the internal combustion engine is stopped without stopping the fuel supply to the internal combustion engine.

  In this case, when the fuel supply stop condition is satisfied when the learning of the purge gas concentration is not completed, the fuel is supplied with the ignition stopped, so the supplied fuel is burned in the combustion chamber. Without being burned with oxygen in the exhaust purification catalyst. As a result, the stored oxygen amount of the exhaust purification catalyst is reduced, so that the rich control time at the time of shifting to the air-fuel ratio feedback control is shortened. Therefore, it becomes possible to start stoichiometric control at an early stage. At this time, the amount of fuel injected can be reduced by reducing the amount of air taken into the internal combustion engine.

  The stored oxygen amount is determined according to the integrated value of the intake air amount during the fuel cut operation.

  According to the present invention, when the predetermined fuel supply stop condition is satisfied when the air-fuel ratio learning is not completed, the rich control time at the time of shifting to the air-fuel ratio feedback control is shortened. Therefore, the stoichiometric control can be started early, so that the start timing of air-fuel ratio learning can be advanced and air-fuel ratio learning can be completed early. The same applies when the purge gas concentration learning is not completed.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the figure, the same reference numerals are used for the same or corresponding parts.

  First, the configuration of the control device according to the present embodiment will be described with reference to FIG. FIG. 1 is a configuration diagram of an internal combustion engine including a control device according to the present embodiment.

  The control apparatus of this embodiment controls the engine 1 which is an internal combustion engine. Although the engine 1 is a multi-cylinder engine, only one cylinder is shown here as a cross-sectional view. As shown in FIG. 1, the engine 1 generates a driving force by igniting an air-fuel mixture in each cylinder 3 with a spark plug 2. During combustion of the engine 1, air sucked from outside passes through the intake pipe 4, is mixed with fuel injected from the injector 5, and is sucked into the cylinder 3 as an air-fuel mixture. The inside of the cylinder 3 and the intake pipe 4 are opened and closed by an intake valve 6. The air-fuel mixture combusted inside the cylinder 3 is exhausted to the exhaust pipe 7 as exhaust gas. An exhaust valve 8 opens and closes the inside of the cylinder 3 and the exhaust pipe 7.

  A throttle valve 9 that adjusts the amount of intake air taken into the cylinder 3 is disposed on the intake pipe 4. A throttle position sensor 10 for detecting the opening degree is connected to the throttle valve 9. The throttle valve 9 is connected to a throttle motor 11 and is opened and closed by the driving force of the throttle motor 11. An accelerator position sensor 12 that detects an operation amount (accelerator opening) of the accelerator pedal 16 is also provided in the vicinity of the throttle valve 9. Thus, in this embodiment, an electronically controlled throttle valve in which the opening degree of the throttle valve 9 is electronically controlled is employed. Furthermore, an air flow meter 13 for detecting the amount of intake air is also mounted on the intake pipe 4.

  A crank position sensor 14 for detecting the position of the crankshaft is attached in the vicinity of the crankshaft of the engine 1. From the output of the crank position sensor 14, the position of the piston 15 in the cylinder 3 and the engine speed can be obtained.

  An exhaust purification catalyst 19 is disposed on the exhaust pipe 7. A plurality of exhaust purification catalysts may be provided on the exhaust pipe. For example, in a four-cylinder engine, one exhaust purification catalyst is arranged at a place where two cylinder exhaust pipes are gathered together, and another one is placed at a place where the remaining two cylinder exhaust pipes are gathered together. An exhaust purification catalyst can also be arranged. In the present embodiment, one exhaust purification catalyst 19 is disposed downstream of the location where the exhaust pipes for each cylinder 3 are gathered together.

  A canister 23 is connected to the fuel tank 20 storing the fuel supplied to the injector 5 through the evaporated fuel passage 22 in order to prevent the evaporated fuel generated therein from being released into the atmosphere. Yes. The evaporated fuel accumulated in the upper space of the fuel tank 20 is guided to the canister 23 through the evaporated fuel passage 22 and is temporarily adsorbed by an adsorbent such as activated carbon in the canister 23.

  The canister 23 is provided with an atmospheric port 26 for introducing outside air. The upper space of the canister 23 communicates with a purge port formed downstream of the throttle valve 9 through a purge passage 27. A variable flow solenoid valve (hereinafter referred to as “purge solenoid valve”) 24 whose opening degree is adjusted by an electronic control unit (hereinafter referred to as “ECU”) 18 is interposed in the purge passage 27.

  When the purge solenoid valve 24 is opened and the intake pipe negative pressure at the purge port acts on the purge passage 27 of the canister 23, air is introduced into the canister 23 from the atmospheric port 26 and is adsorbed by activated carbon or the like in the canister 23. The evaporated fuel is desorbed. The desorbed evaporated fuel is sucked into the intake pipe 4 of the engine 1 through the purge passage 27 together with the air introduced from the atmospheric port 26. The evaporated fuel sucked into the intake pipe 4 is burned in the cylinder 3 of the engine 1 and processed.

  The spark plug 2, injector 5, throttle position sensor 10, throttle motor 11, accelerator position sensor 12, air flow meter 13, crank position sensor 14 and other sensors are connected to an ECU 18 that comprehensively controls the engine 1. It is controlled based on a signal from the ECU 18 or sends a detection result to the ECU 18. A catalyst temperature sensor 21 that measures the temperature of the exhaust purification catalyst 19 disposed on the exhaust pipe 7 is also connected to the ECU 18.

Further, an air-fuel ratio sensor 25 attached to the upstream side of the exhaust purification catalyst 19 is also connected to the ECU 18. The air-fuel ratio sensor 25 detects the exhaust air-fuel ratio from the oxygen concentration in the exhaust gas at the mounting position. As the air-fuel ratio sensor 25, an O ₂ sensor that detects the exhaust air-fuel ratio on and off is used. As the air-fuel ratio sensor 25, a linear air-fuel ratio sensor that can linearly detect the exhaust air-fuel ratio may be used. Further, since the air-fuel ratio sensor 25 cannot accurately detect the air-fuel ratio unless the temperature exceeds a predetermined temperature (activation temperature), the air-fuel ratio sensor 25 is supplied via the ECU 18 so that the temperature is raised to the activation temperature early. The temperature is raised by the generated electric power.

  The ECU 18 has its stored contents held by a microprocessor that performs calculations therein, a ROM that stores programs for causing the microprocessor to execute various processes, a RAM that stores various data such as calculation results, and a battery. It has a backup RAM and the like.

  The ECU 18 has a fuel cut portion 18a that cuts off the fuel supply to the engine 1 when a predetermined fuel cut condition is satisfied, according to the stored oxygen amount of the exhaust purification catalyst 19 when returning from the fuel cut operation. An air-fuel ratio control unit 18b that controls the air-fuel ratio of the air-fuel mixture to the rich side, an ignition control unit 18c that controls ignition of the air-fuel mixture, and the like are constructed.

  Further, the ECU 18 executes the calculation of the oxygen storage amount stored in the exhaust purification catalyst 19, the air-fuel ratio control of the air-fuel mixture sucked into the engine 1, the air-fuel ratio learning, the learning of the purge gas concentration, and the like.

  Here, the oxygen storage function of the exhaust purification catalyst 19 will be described. The exhaust purification catalyst 19 is a three-way catalyst having a honeycomb structure mainly composed of cordierite. A carrier layer made of a coating material such as alumina (Al2O3) or zirconia (ZrO2) is formed on the surface of the honeycomb structure, and a platinum-rhodium (Pt-Rh) noble metal catalyst material is supported on the carrier layer. ing.

  The exhaust purification catalyst 19 has a function of oxidizing unburned components (HC, CO) and simultaneously reducing nitrogen oxides (NOx) when the air-fuel ratio of the inflowing exhaust gas is the stoichiometric air-fuel ratio. Further, the exhaust purification catalyst 19 has a property (oxygen storage function) to occlude (adsorb and store) and release oxygen molecules in the inflowing exhaust gas by supporting components such as ceria. With the oxygen storage function, HC, CO and NOx can be purified even if the air-fuel ratio deviates from the stoichiometric air-fuel ratio to some extent. That is, the exhaust purification catalyst 19 occludes excess oxygen and removes oxygen from the nitrogen oxide NOx when the exhaust gas flowing in with the lean exhaust air-fuel ratio contains a large amount of excess oxygen and nitrogen oxide NOx. (Reducing NOx) and occluding oxygen, thereby purifying NOx. Further, the exhaust purification catalyst 19 can absorb oxygen molecules stored in the exhaust gas when the exhaust gas flowing in in a rich exhaust air-fuel ratio contains a large amount of unburned components such as hydrocarbon HC and carbon monoxide CO. These unburned components are fed to oxidize the unburned components, thereby purifying CO and HC.

  Therefore, if the exhaust purification catalyst 19 stores oxygen to the limit at which oxygen can be stored, oxygen cannot be stored when the exhaust air-fuel ratio becomes lean. Therefore, NOx purification using the oxygen storage function can be performed. Can no longer contribute. On the other hand, unless the exhaust purification catalyst 19 has released oxygen and occluded oxygen at all, oxygen cannot be released when the exhaust air-fuel ratio becomes rich. Therefore, HC and CO purification utilizing the oxygen storage function Can no longer contribute. Therefore, even if the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst 19 becomes transiently lean or rich, the oxygen storage amount is accurately adjusted so that the components to be purified can be sufficiently purified. It is desirable to perform air-fuel ratio control so that the oxygen storage amount is maintained at a predetermined value while being well estimated.

  Next, an overview of air-fuel ratio feedback control and air-fuel ratio learning in the engine 1 will be described with reference to FIG.

  The air-fuel ratio feedback control is performed so that the air-fuel ratio of the air-fuel mixture becomes the target air-fuel ratio for the purpose of reducing exhaust emissions. This air-fuel ratio feedback control is executed by a program built in the ROM in the ECU 18 based on detection results from various sensors connected to the ECU 18.

  Based on the outputs from the various sensors described above, the ECU 18 performs air-fuel ratio feedback control and other correction control described below to finally determine the fuel injection amount TAU, and determines the determined fuel injection amount TAU. Fuel is injected from the injector 5.

  The fuel injection amount TAU when operating the engine 1 is determined as follows.

TAU = α × TAUP × EFTOTAL + β (1)
Here, TAUP is a basic fuel injection amount determined from the intake air amount and the engine speed, and the final fuel injection amount TAU is determined by correcting this basic fuel injection amount TAUP according to the engine operating state. To do. The basic fuel injection amount TAUP may be obtained from the intake pressure and the engine speed. The basic fuel injection amount TAUP can also be obtained from the accelerator opening and the engine speed.

  EFTOTAL is an air-fuel ratio reflecting total value. The air-fuel ratio reflected total value EFTOTAL is a component that corrects the basic fuel injection amount TAUP in order to set the air-fuel ratio, such as an intake air temperature correction value based on the intake air temperature, to the target air-fuel ratio. I do. α and β are other correction components such as a warm-up increase correction value immediately after startup and an acceleration increase correction value during acceleration. This EFTOTAL is represented by, for example, the sum of an air-fuel ratio feedback correction coefficient FAF and an air-fuel ratio learning value KG. That is, in this case, the above equation (1) is expressed as follows.

TAU = α × TAUP × (FAF + KG) + β (2)
The air-fuel ratio feedback correction coefficient FAF is for detecting the air-fuel ratio from the oxygen concentration in the exhaust gas by the air-fuel ratio sensor 25 and performing feedback correction so that this air-fuel ratio becomes the target air-fuel ratio. For example, when the air-fuel ratio is the stoichiometric air-fuel ratio, the air-fuel ratio detected by the air-fuel ratio sensor 25 is richer than the stoichiometric air-fuel ratio, as shown in FIGS. 2 (a) and 2 (b). During this time, a value for gradually decreasing the fuel injection amount is given to the air-fuel ratio feedback correction coefficient FAF, and when the air-fuel ratio detected by the air-fuel ratio sensor 25 changes from rich to lean, the fuel is taken into consideration to improve responsiveness. A value for increasing the injection amount is given in a skipping manner.

  Conversely, while the air-fuel ratio detected by the air-fuel ratio sensor 25 is leaner than the stoichiometric air-fuel ratio, a value that gradually increases the fuel injection amount is given to the air-fuel ratio feedback correction coefficient FAF. When the air-fuel ratio detected by (1) changes from lean to rich, a value for reducing the fuel injection amount is given in a skipping manner in consideration of improvement in response. In this way, the air-fuel ratio feedback correction coefficient FAF is generated in order to always maintain the air-fuel ratio at the stoichiometric air-fuel ratio.

  In consideration of the detection delay of the air-fuel ratio sensor 25, delay times DT1 and DT2 as shown in FIG. 2C may be set in the air-fuel ratio feedback correction coefficient FAF.

  On the other hand, the air-fuel ratio learning value KG is a correction value for reflecting individual differences and changes with time of engines such as the injector 5 and the air-fuel ratio sensor 25. The air-fuel ratio learning value KG is generated from the air-fuel ratio feedback correction coefficient FAFAV obtained by averaging the air-fuel ratio feedback correction coefficient FAF. Specifically, the air-fuel ratio learning value KG is obtained from the deviation between the center value of the air-fuel ratio feedback correction coefficient FAFAV and the reference value (1.0).

  When the air-fuel ratio feedback correction average value FAFAV takes a value close to lean, the air-fuel ratio learning value KG is increased in order to increase the fuel injection amount TAU. On the other hand, when the air-fuel ratio feedback correction average value FAFAV takes a rich value, the air-fuel ratio learning value KG is decreased in order to decrease the fuel injection amount TAU. The air-fuel ratio learning value KG is stored in the backup RAM in the ECU 18 after learning and is read out when necessary.

  Next, the operation of the control device according to the present embodiment will be described with reference to FIG. Here, FIG. 3 is a flowchart showing a processing procedure of the stored oxygen amount control of the exhaust purification catalyst. This stored oxygen amount control is started and executed in synchronization with the rotation of the engine 1.

  In step S100, a determination is made as to whether there is a fuel cut request. Here, when there is a fuel cut request, that is, when the fuel cut condition is satisfied, there are a time when the vehicle is decelerated, a time when the engine is rotating at a high speed, a time when the vehicle speed is high, and the like. Here, a fuel cut at the time of vehicle deceleration will be described as an example. That is, when the accelerator pedal 16 is released and the engine speed is greater than or equal to a predetermined value, it is determined that the vehicle is decelerating and a fuel cut request is output.

  If step S100 is positive, that is, if there is a fuel cut request, the process proceeds to step S102. On the other hand, if there is no fuel cut request, the process proceeds to step S118.

  In step S118, it is determined whether or not there is a rich control request at the time of fuel cut return. Here, when there is a rich control request, that is, when the stored oxygen amount of the exhaust purification catalyst 19 is equal to or greater than a predetermined value, the air-fuel ratio is controlled to the rich side until the stored oxygen amount becomes less than the predetermined value ( Step S120). On the other hand, when there is no rich control request, that is, when the stored oxygen amount is less than the predetermined value, the rich control of the air-fuel ratio is not executed and the fuel injection amount TAU calculated by the above equation (2) is used. Then, fuel injection is executed (step S122).

  If step S100 is positive, a determination is made in step S102 as to whether air-fuel ratio learning has been completed. Here, it is assumed that the air-fuel ratio learning is completed when the air-fuel ratio feedback coefficient is continuously within a predetermined range for a predetermined time.

  If it is determined in step S102 that the air-fuel ratio learning has been completed, the process proceeds to step S116, and the fuel cut process is executed. Note that the amount of oxygen stored in the exhaust purification catalyst 19 is calculated during the fuel cut. The stored oxygen amount is calculated based on the exhaust air amount and the oxygen concentration. However, since the exhaust gas becomes air during the fuel cut operation, the oxygen concentration matches the oxygen ratio (about 20%) in the air.

  On the other hand, if it is determined that the air-fuel ratio learning has not been completed, the process proceeds to step S104.

  In step S104, the ignition of the air-fuel mixture by the spark plug 2 is stopped. In the subsequent step S106, the throttle valve 9 is throttled, and the amount of intake air taken into the engine 1 is reduced. In the present embodiment, the throttle valve 9 is adjusted in accordance with the accelerator pedal opening, and at the time of idling, a target idle speed and an actual idle speed set according to the operating state of the engine 1 are determined. The throttle valve opening is controlled so as to match. Therefore, even if the accelerator pedal 16 is fully closed, the throttle valve 9 may be opened by idle speed control. In such a case, the throttle valve 9 is closed regardless of the idle speed control.

  Instead of the electronically controlled throttle valve, an idle speed control may be performed using an ISC (Idle Speed Control). In this case, control is performed so that the opening degree of the valve constituting the ISC is fully closed, and the intake air amount is reduced.

  In the subsequent step S108, it is determined whether or not there is a rich control request at the time of fuel cut return. Here, when there is no rich control request at the time of fuel cut return, that is, when the stored oxygen amount of the exhaust purification catalyst 19 is less than a predetermined value, the process proceeds to step S116 and the fuel cut process is executed.

  On the other hand, when there is a rich control request at the time of fuel cut recovery, that is, when the stored oxygen amount of the exhaust purification catalyst 19 is equal to or greater than a predetermined value, the process proceeds to step S110.

  In step S110, a determination is made as to whether or not the temperature of the exhaust purification catalyst 19 is equal to or higher than a predetermined activation temperature. Here, when the temperature of the exhaust purification catalyst 19 is lower than a predetermined activation temperature, that is, when the exhaust purification catalyst 19 is not activated and the fuel cannot be burned, the process proceeds to step S116 and the fuel cut is performed. Processing is executed.

  On the other hand, when the temperature of the exhaust purification catalyst 19 is equal to or higher than a predetermined activation temperature, that is, when the exhaust purification catalyst 19 is activated and the fuel can be combusted, the process proceeds to step S112.

  In step S112, the fuel injection amount injected from the injector 5 is obtained according to the intake air amount of the engine 1. Then, the injector 5 is opened based on the determined fuel injection amount, and fuel is injected (step S114). Thereafter, the process is temporarily terminated.

  As described above, according to the control device according to the present embodiment, even when the fuel cut operation is required, when the air-fuel ratio learning is not completed, the fuel injection is executed and the mixture is ignited. Stopped. Therefore, the injected fuel is burned by the exhaust purification catalyst 19 without being burned in the combustion chamber of the engine 1. As a result, the amount of oxygen stored in the exhaust purification catalyst 19 can be reduced, and the rich control time can be shortened. Since the air-fuel ratio learning can be started early by shortening the rich control time, it is possible to advance the completion time of the air-fuel ratio learning.

  Further, at the time of the above control, the amount of air sucked into the engine 1 is reduced by closing the throttle valve 9, so that the fuel injection amount can be reduced.

  In step S102, the process is switched depending on whether or not air-fuel ratio learning is completed. However, instead of or in addition to the condition whether or not air-fuel ratio learning is completed, purge concentration learning is performed. Processing may be switched depending on whether or not the processing is completed. That is, when the purge concentration learning is completed, the fuel cut is executed in step S116, and when the purge concentration learning is not completed, the processing for suppressing the increase in the stored oxygen amount in steps S104 to S114 is executed. The Whether or not the purge concentration learning is completed is determined based on whether or not the purge concentration learning value has been updated a predetermined number of times (for example, 20 times).

  In general, when the purge process is performed, the detection result of the air-fuel ratio sensor 25 is affected, so that accurate learning of the air-fuel ratio cannot be performed. Therefore, the purge process and the purge concentration learning are started after the air-fuel ratio learning is completed. Further, when the purge concentration learning is not completed, purging is prohibited during the rich control.

  According to this embodiment, since the rich control time is shortened and the air-fuel ratio learning is completed early, the start time of the purge concentration learning can be advanced. Therefore, the purge concentration learning can be completed early, and the adsorption ability of the activated carbon or the like inside the canister can be recovered early.

It is sectional drawing of an internal combustion engine provided with the control apparatus which concerns on embodiment. Air-fuel ratio feedback control (a) O ₂ sensor output waveform diagrams showing another example of (b) an air-fuel ratio feedback correction coefficient FAF waveform, (c) air-fuel ratio feedback correction coefficient FAF waveform. It is a flowchart which shows the process sequence of occluded oxygen amount control by the control apparatus which concerns on embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Spark plug, 3 ... Cylinder, 4 ... Intake pipe, 5 ... Injector, 7 ... Exhaust pipe, 9 ... Throttle valve, 18 ... ECU, 18a ... Fuel cut part, 18b ... Air-fuel ratio control part, 18c ... Ignition control unit, 19 ... exhaust purification catalyst, 25 ... air-fuel ratio sensor.

Claims (5)

An internal combustion engine that stops fuel supply to the internal combustion engine when a predetermined fuel supply stop condition is satisfied, and controls the air-fuel ratio to the rich side according to the stored oxygen amount of the exhaust purification catalyst when returning from the fuel stop operation In the engine control device,
An internal combustion engine that stops ignition in the internal combustion engine without stopping fuel supply to the internal combustion engine when the fuel supply stop condition is satisfied when air-fuel ratio learning is not completed. Engine control device. An internal combustion engine that stops fuel supply to the internal combustion engine when a predetermined fuel supply stop condition is satisfied, and controls the air-fuel ratio to the rich side according to the stored oxygen amount of the exhaust purification catalyst when returning from the fuel stop operation In the engine control device,
A control apparatus for an internal combustion engine, wherein when the fuel supply stop condition is satisfied when air-fuel ratio learning is not completed, the amount of air taken into the internal combustion engine is reduced.   The ignition in the internal combustion engine is stopped without stopping the fuel supply to the internal combustion engine when the fuel supply stop condition is satisfied when the air-fuel ratio learning is not completed. Item 3. A control device for an internal combustion engine according to Item 2. An internal combustion engine that stops fuel supply to the internal combustion engine when a predetermined fuel supply stop condition is satisfied, and controls the air-fuel ratio to the rich side according to the stored oxygen amount of the exhaust purification catalyst when returning from the fuel stop operation In the engine control device,
If the fuel supply stop condition is satisfied when the purge gas concentration learning is not completed, the amount of air sucked into the internal combustion engine is reduced, and the fuel supply to the internal combustion engine is stopped without stopping the fuel supply stop condition. A control apparatus for an internal combustion engine, characterized by stopping ignition in the internal combustion engine.   5. The control device for an internal combustion engine according to claim 1, wherein the stored oxygen amount is obtained according to an integrated value of an intake air amount during a fuel cut operation.

Images