JP5867441B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine having a plurality of injectors for one cylinder.

  An in-cylinder fuel injection injector that directly injects fuel into a cylinder, and an intake path fuel injection injector that injects fuel into an intake path and an internal combustion engine having a plurality of injectors, the in-cylinder fuel injection and the intake path fuel injection are performed in the engine. The air-fuel ratio feedback control is performed so that the air-fuel ratio of the injected fuel and the intake air becomes the stoichiometric air-fuel ratio while being executed at a predetermined sharing ratio according to the rotation speed and the load (for example, Patent Document 1).

JP 2005-307756 A

There is a feedback correction coefficient as an element of the air-fuel ratio feedback control. If the feedback correction coefficient remains fixed, optimal air-fuel ratio feedback control becomes difficult due to changes in the vehicle state and environment. As a result, fuel consumption is deteriorated, CO ₂ (carbon dioxide) emission is increased, HC (hydrocarbon) emission is increased, and vehicle running performance and maneuverability are deteriorated. Therefore, in order to learn the feedback correction coefficient for each injector, it is necessary to set an opportunity for learning by individually injecting each injector. However, the operating state in which the correction coefficient for feedback is learned is not always appropriate for the single injection of each injector. Therefore, this learning may cause a temporary deterioration in fuel consumption, an increase in CO ₂ (carbon dioxide) emissions, an increase in HC (hydrocarbon) emissions, a deterioration in driving performance and maneuverability of the vehicle, and the like. It becomes.

The present invention takes the above circumstances into consideration, and the object thereof is to optimize the learning of air-fuel ratio feedback control without performing individual injection of each injector, thereby reducing fuel consumption and reducing CO ₂ emissions. It is an object of the present invention to provide a control device for an internal combustion engine that can achieve reductions, reductions in HC emissions, vehicle running performance and maneuverability.

A control apparatus for an internal combustion engine according to a first aspect of the present invention includes an intake path injector for injecting fuel into an intake path and an in-cylinder injector for injecting fuel into a cylinder. In accordance with the operating state of the internal combustion engine, a sharing determination means for determining a share between the fuel injection by only the intake passage injector and the fuel injection by the intake passage injector and the in-cylinder injector, Air-fuel ratio feedback control means for performing air-fuel ratio feedback control on the fuel injection amount based on the output of the fuel ratio sensor. The air-fuel ratio feedback control means learns the optimum value of the proportional correction coefficient of the air-fuel ratio feedback control of the fuel injection amount of the intake passage injector when the fuel is injected only by the intake passage injector. Optimizing the integral correction coefficient of the air-fuel ratio feedback control of the fuel injection amount of the in-cylinder injector using the learned optimal value of the proportional correction coefficient when fuel is being injected by the injector and the in-cylinder injector Learn the value. The allocation determining means, the air-fuel ratio feedback control that the fuel injection quantity of fuel is injected both or by one of said cylinder injection injector and the intake passage injector in Jefferies Kuta based on the determination by said air-fuel ratio feedback control means when it is, when said optimum value of the proportional correction coefficient is not learned performs only the fuel injection the intake passage injector.

  According to the control device for an internal combustion engine of the present invention, since learning of a plurality of injectors for one cylinder can be performed without putting into a special operation state, fuel consumption, CO2 emissions, HC emissions, etc. can be quickly suppressed, or It is possible to learn feedback control without deteriorating vehicle running performance or maneuverability.

The figure which shows the structure of one Embodiment. The flowchart for demonstrating the effect | action of one Embodiment. The figure which shows the change of the feedback correction coefficient in one Embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes an internal combustion engine having a cylinder 2, a piston 3, a spark plug 4, an intake valve 5, and an exhaust valve 6, and when the piston 3 descends, an intake port 7 and an intake air are brought into the combustion chamber in the cylinder 2. Air is sucked through the valve 5 (intake stroke).

  The intake port 7 is provided with an air flow meter 21 for detecting the intake air amount and a throttle valve 22 for determining the intake air amount. Further, the in-cylinder injector 11 is provided so as to face the combustion chamber in the cylinder 2, and the intake passage injector 12 is provided so as to face the intake passage of the intake port 7. The in-cylinder injector 11 injects fuel into the combustion chamber. The intake passage injector 12 injects fuel toward the intake valve 5 in the intake passage.

  The fuel injected by the in-cylinder injector 11 is mixed with the intake air from the intake passage and the intake valve 5 in the combustion chamber. The fuel injected by the intake passage injector 12 is mixed with the intake air in the intake passage, and the mixture is supplied into the combustion chamber via the intake valve 5.

  The air-fuel mixture is compressed by the ascending of the piston 3 (compression stroke), and the compressed air-fuel mixture is ignited by the spark of the spark plug 4 to burn and explode (combustion stroke). The piston 3 descends again by this combustion / explosion, and the above operation is repeated. The gas generated by the combustion / explosion is discharged through the exhaust valve 6 and the exhaust port 8 (exhaust stroke).

  The exhaust port 8 is provided with an air-fuel ratio sensor 23 that detects the air-fuel ratio of the exhaust gas that has passed through the exhaust valve 6 and a catalyst 24 that purifies the exhaust gas.

  Reference numeral 30 denotes a fuel tank having a feed pump 31 for sending out fuel. Fuel is sent from the feed pump 31 to the fuel pipe 32, and the fuel is supplied to the in-cylinder injector 11 by the fuel pipe 32, the branch pipe 32a, and the high-pressure pump 33 on the branch pipe 32a. Further, the fuel in the fuel pipe 32 is supplied to the in-cylinder injector 11 by the branch pipe 32b.

  On the other hand, the ECU 40 serving as a control unit is connected to the injectors 11 and 12, the air flow meter 21, the throttle valve 22, the air / fuel ratio sensor 23, the feed pump 31, the high pressure pump 33, the ignition coil 41, the crank angle sensor 42, and the cooling water temperature sensor 43. The accelerator opening sensor 44 is connected.

  The ignition coil 41 supplies a driving voltage for ignition to the ignition plug 4. The crank angle sensor 42 detects a crank angle that is linked to the vertical movement of the piston 3. The cooling water temperature sensor 43 detects the cooling water temperature of the internal combustion engine 1. The accelerator opening sensor 44 detects the accelerator opening (the amount by which the accelerator pedal is depressed).

The ECU 40 has the following means (1) to (7) as main functions related to the control of the internal combustion engine 1.
(1) A rotational speed detection means for detecting (calculating) the rotational speed Ne of the internal combustion engine 1 from the detection angle of the crank angle sensor 42.

  (2) Load detection means for detecting the load L of the internal combustion engine 1 from the detected opening of the accelerator opening sensor 44 and the detected amount of the air flow meter 21.

  (3) A sharing rate determining means for determining a sharing rate between the in-cylinder fuel injection of the in-cylinder injector 11 and the intake channel fuel injection of the intake channel injector 12 according to the detected rotation speed Ne and the load L.

  (4) Determination means for determining whether or not the detected rotation speed Ne and load L are within a predetermined air-fuel ratio feedback control range.

  (5) The air-fuel ratio for controlling the fuel injection amount of one or both of the injectors 11 and 12 so that the air-fuel ratio detected by the air-fuel ratio sensor 23 becomes the stoichiometric air-fuel ratio when the determination result of the determination means is affirmative. Air-fuel ratio feedback control means for executing feedback control.

(6) When the determination result of the determination means is affirmative and at a predetermined learning timing, only the intake passage fuel injection of the intake passage injection injector 12 is performed and proportional correction (P1) of air-fuel ratio feedback control is executed. First learning means for learning, updating and storing the optimum value of the proportional correction coefficient Kp1. The predetermined learning timing is, for example, a predetermined time.

  (7) After the learning of the first learning means is completed, the intake path fuel injection of the intake path injector 12 and the in-cylinder fuel injection of the in-cylinder injector 11 are performed, and the intake path injector 12 is made the first learning means. While performing the air-fuel ratio feedback control with the proportional correction coefficient Kp1 learned in step 1 and executing the integral correction (I2) of the air-fuel ratio feedback control of the in-cylinder injector 11, the optimum value of the integral correction coefficient Ki2 is learned and updated and stored. Second learning means.

Next, the operation will be described with reference to the flowchart of FIG.
The rotational speed Ne is detected from the detection angle of the crank angle sensor 42 (step 101), and the load L is detected from the detection opening of the accelerator opening sensor 44 and the detection amount of the air flow meter 21 (step 102). Then, the share ratio between the in-cylinder fuel injection of the in-cylinder injector 11 and the intake passage fuel injection of the intake passage injector 12 is determined according to the detected rotation speed Ne and the load L (step 103). In this case, the condition data for determining the sharing rate is stored in the internal memory of the ECU 40, and the sharing rate is determined by referring to the condition data based on the rotational speed Ne and the load L. Basically, the intake passage fuel injection of the intake passage injector 12 is performed at a low load, and both the in-cylinder fuel injection of the in-cylinder injector 11 and the intake passage fuel injection of the intake passage injection injector 12 are performed at a high load. This is because fuel injected from the in-cylinder injector 11 is vaporized by heat in the air without adhering to the intake passage, so that the charging efficiency is improved, which is advantageous for high-load operation.

  Further, it is determined whether or not the rotational speed Ne and the load L are within a predetermined air-fuel ratio feedback control range (step 105). If this determination result is negative (NO in step 105), open-loop control of the air-fuel ratio related to fuel injection of one or both of the injectors 11 and 12 is executed (step 106). That is, the air-fuel ratio feedback control is not executed.

  If the determination result is affirmative (YES in step 105), that is, if the rotational speed Ne and the load L are within the air-fuel ratio feedback control region, the air-fuel ratio detected by the air-fuel ratio sensor 23 becomes the stoichiometric air-fuel ratio. Thus, air-fuel ratio feedback control for controlling the fuel injection amount of one or both of the injectors 11 and 12 is executed (step 107).

  FIG. 3 shows changes in the feedback correction coefficient K of the air-fuel ratio feedback control when fuel is injected by both the in-cylinder injector 11 and the intake passage injector 12. That is, the proportional correction (P1) of the air-fuel ratio feedback control is executed at the time of fuel injection of the intake passage injector 12, and when the air-fuel ratio is reversed from rich to lean, the feedback correction coefficient K is equal to the proportional correction coefficient Kp1. Will be increased. When the air-fuel ratio is reversed from lean to rich, the feedback correction coefficient K is decreased by the proportional correction coefficient Kp1.

  On the other hand, when fuel is injected from the in-cylinder injector 11, integral correction (I) of air-fuel ratio feedback control is executed. When the air-fuel ratio is rich, the feedback correction coefficient K is decreased by the integral correction coefficient Nx. If the air-fuel ratio is lean, the feedback correction coefficient K is increased by the integral correction coefficient Nx.

When the air-fuel ratio feedback control range is entered (YES in step 105) and a predetermined learning timing is reached (YES in step 108), only the intake passage fuel injection of the intake passage injector 12 is executed (step 109). Proportional correction (P1) of air-fuel ratio feedback control related to the intake passage fuel injection is executed (step 110 ). Then, the optimum value of the proportional correction coefficient Kp1 of the proportional correction (P1) is learned in a state where the intake passage fuel injection and the proportional correction (P1) are executed (step 111).

When learning of the optimum value of the proportional correction coefficient Kp1 is completed (YES in step 112), both the intake passage fuel injection of the intake passage injector 12 and the in-cylinder fuel injection of the in-cylinder injector 11 are executed with the optimum value. Is updated and stored in the internal memory of the ECU 40 as the proportional correction coefficient Kp1 of the intake manifold injector 12 (step 113).

  Subsequently, both the intake passage fuel injection of the intake passage injector 12 and the in-cylinder fuel injection of the in-cylinder injector 11 are executed (step 114). Along with this, proportional correction (P1) of air-fuel ratio feedback control related to intake-path fuel injection is executed (step 115), and integral correction of air-fuel ratio feedback control related to in-cylinder fuel injection of in-cylinder injector 11 ( I2) is executed (step 116).

  In this state, the average value of the integral correction coefficient Ki2 for the integral correction (I2) is calculated (step 118). Then, when a predetermined time necessary for calculating the average value has elapsed, an optimum value of the integral correction coefficient Ki2 is obtained from the calculated average value under the determination that the calculation is complete (YES in Step 117) (Step S1). 119). The obtained optimum value is an integral correction coefficient Ki2 of the in-cylinder injector 11 when both the intake passage fuel injection of the intake passage injector 12 and the in-cylinder fuel injection of the in-cylinder injector 11 are executed. It is updated and stored in the internal memory (step 120).

As described above, the optimum value of the proportional correction coefficient Kp1 of the intake passage injection injector 12 that performs fuel injection alone is learned, and then the intake passage when the intake passage injector 12 and the in-cylinder injection injector 11 perform fuel injection. By performing the air-fuel ratio feedback control of the injection injector 12 with the proportional correction coefficient Kp1, and learning the optimum value of the integral correction coefficient Ki2 of the in-cylinder injector 11, the fuel injection by the intake passage injection injector 12 at low load is learned. proportional correction coefficient Kp1, high in load of the fuel injection in the intake passage injector 12 and the in-cylinder injection injector 11 and the proportional correction coefficient Kp1 learned integration correction by a factor Ki2 the air-fuel ratio feedback control vehicle state and changes in the environment, such as Regardless of the situation, it can always be maintained in an optimum state. Therefore, it is possible to improve fuel consumption, CO ₂ emissions, HC emissions, vehicle running performance and maneuverability.

  In addition, since the in-cylinder injector 11 does not have to perform fuel injection alone for learning, an in-cylinder injector is used in an internal combustion engine that uses the in-cylinder injector 11 as an assist for the intake manifold injector 12. Therefore, it is not necessary to set a special driving state of 11 individual fuel injections, and feedback control learning can be performed without deteriorating the vehicle running performance or the maneuverability.

  Although only one cylinder has been described, the present invention can be similarly applied to a case having a plurality of cylinders. In addition, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Cylinder, 3 ... Piston, 4 ... Spark plug, 5 ... Intake valve, 6 ... Exhaust valve, 7 ... Intake port, 8 ... Exhaust port, 11 ... In-cylinder injector, 12 ... Intake path injection Injector, 21 ... Air flow meter, 22 ... Throttle valve, 23 ... Air-fuel ratio sensor, 24 ... Catalyst, 40 ... ECU (control unit), 41 ... Ignition coil, 42 ... Crank angle sensor, 43 ... Cooling water temperature sensor, 44 ... Accelerator position sensor

Claims (2)

In a control device for an internal combustion engine comprising an intake passage injector for injecting fuel into an intake passage and an in-cylinder injector for injecting fuel into a cylinder, the intake air in accordance with an operating state of the internal combustion engine Sharing determination means for determining sharing between fuel injection only by the road injection injector and fuel injection by the intake path injection injector and the in-cylinder injection;
Air-fuel ratio feedback control means for air-fuel ratio feedback control of the fuel injection amount based on the output of the air-fuel ratio sensor,
The air-fuel ratio feedback control means learns the optimum value of the proportional correction coefficient of the air-fuel ratio feedback control of the fuel injection amount of the intake passage injector when the fuel is injected only by the intake passage injector.
Integral correction of air-fuel ratio feedback control of the fuel injection amount of the in-cylinder injector using the optimal value of the learned proportional correction coefficient when fuel is being injected by the intake manifold injector and the in-cylinder injector Learn the optimal value of the coefficient ,
The allocation determining means, the air-fuel ratio feedback control that the fuel injection quantity of fuel is injected both or by one of said cylinder injection injector and the intake passage injector in Jefferies Kuta based on the determination by said air-fuel ratio feedback control means when it is, the proportional when the optimum value of the correction coefficient is not learned, the control apparatus for an internal combustion engine and performs only the fuel injection the intake passage injector. The allocation determining means that the during the low load operation of the internal combustion engine the determines by that injected only into the intake passage injector, at the time of high load operation to determine the injection by said cylinder injection injector and the intake passage injector The control device for an internal combustion engine according to claim 1.

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