JP2004162725A - Torque controller for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of difference in torque steps even when switching homogeneous combustion and stratified combustion in an engine controlling amount of suction air and amount of fuel supply of the engine to obtain target engine torque and target equivalence ratio. <P>SOLUTION: Target amount of suction air TTPO corresponding to reference equivalence ratio is computed based on the target engine torque tTEO and engine rotation speed NE. Either of a table for homogeneous combustion and a table for stratified combustion is selected as a table storing combustion efficiency compensation rate ITAF in accordance with the target equivalence ratio tDML to obtain the combustion efficiency compensation rate ITAF. The target amount of suction air TTPO is compensated by the combustion efficiency compensation rate ITAF and is further compensated in accordance with the target equivalence ratio tDML to compute final target amount of suction air TTP2 in order to control a throttle actuator in accordance with the target amount of suction air TTP2. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to an engine torque control device, and more particularly, to a control device configured to control an intake air amount and a fuel supply amount of an engine so as to obtain a target engine torque and a target equivalent ratio according to an operation state of the engine. .

2. Description of the Related Art As a conventional engine torque control device, for example, there is one disclosed in Patent Document 1.
In this apparatus, a target throttle valve opening is obtained from a target engine torque and an engine rotation speed, and a throttle actuator is controlled based on the target throttle valve opening.
JP-A-62-110536

  However, in the above-described conventional engine torque control device, the target throttle valve opening is directly searched for from the target engine torque and the engine rotation speed. , And cannot be applied to an engine in which the equivalent ratio is variably controlled according to the operating state.

  Further, in recent years, a fuel injection valve that injects fuel directly into a combustion chamber of an engine is provided, and the homogeneous combustion that injects fuel in an intake stroke and the stratified combustion that injects fuel in a compression stroke are operating ranges. A spark-ignition direct-injection engine has been developed that can be switched in response to the following conditions.However, in such an engine, the generated torque is different at the same equivalence ratio between homogeneous combustion and stratified combustion. Only by changing the air amount control value, the target engine torque cannot be obtained with high accuracy, and there is a problem that a torque step occurs when switching between homogeneous combustion and stratified combustion.

  The present invention has been made in view of the above problems, and in the spark ignition type direct injection engine in which the switching of the combustion state is performed together with the change of the target equivalent ratio, the target equivalent ratio and the combustion state are changed and switched. Another object of the present invention is to provide a torque control device capable of controlling the target engine torque with high accuracy, and to avoid occurrence of a torque step when switching between homogeneous combustion and stratified combustion.

  Therefore, the invention according to claim 1 calculates the target intake air amount corresponding to the target engine torque and the target equivalence ratio according to the operating state of the engine, and corrects the target intake air amount according to the combustion state. The engine intake air amount is controlled based on the corrected target intake air amount.

According to this configuration, the target intake air amount is calculated to obtain a target engine torque corresponding to the operating state of the engine at a target equivalence ratio, but the target intake air amount is corrected according to the combustion state, and The actual intake air amount is controlled based on the corrected target intake air amount.
The control of the intake air amount according to the target intake air amount is performed, for example, by obtaining a target throttle valve opening corresponding to the target intake air amount, and controlling a throttle actuator based on the target throttle valve opening.

On the other hand, the fuel supply control to the engine is performed so as to form the mixture at the equivalent ratio.
According to the second aspect of the present invention, a fuel injection valve for directly injecting fuel into the combustion chamber of the engine is provided, and homogeneous combustion is performed by injecting fuel in an intake stroke, and stratified combustion is performed by injecting fuel in a compression stroke. Are switchable, and the correction of the target intake air amount according to the combustion state is a correction of the target intake air amount according to the homogeneous combustion and the stratified combustion.

According to such a configuration, it is possible to perform homogeneous combustion or stratified combustion by the fuel injection valve that directly injects fuel into the combustion chamber, and a difference in generated torque (combustion efficiency) due to the difference between the homogeneous combustion and the stratified combustion. The target intake air amount is corrected to cope with the above.
On the other hand, the invention according to claim 3 is configured as shown in FIG.

In FIG. 1, the accelerator operation amount detecting means detects the accelerator operation amount, and the engine rotational speed detecting means detects the engine rotational speed.
The target intake air amount calculating means calculates a target engine torque corresponding to the detected accelerator operation amount and the detected engine speed and a target intake air amount corresponding to the reference equivalence ratio.

The correction means based on the target equivalence ratio corrects the target intake air amount to a target intake air amount corresponding to the target equivalence ratio corresponding to the detected accelerator operation amount and a target equivalence ratio corresponding to the engine speed. .
Further, the correction means based on the combustion state corrects the target intake air amount according to the combustion state.

Here, the intake air amount control means controls the intake air amount of the engine based on the target intake air amount corrected by the correction means based on the target equivalence ratio and the correction means based on the combustion state.
According to such a configuration, the intake air amount obtained from the target engine torque corresponding to the accelerator operation amount and the engine rotation speed at the reference equivalent ratio is calculated as the target intake air amount. Here, the target equivalence ratio is variably controlled in accordance with the accelerator operation amount and the engine rotation speed. Therefore, the target intake air amount corresponding to the variably controlled target equivalence ratio is determined by the target equivalence ratio of the target intake air amount. It is determined by the correction according to. Further, even if the target equivalence ratio is the same, the target intake air amount is corrected in accordance with the combustion state in order to cope with the difference in generated torque (combustion efficiency) depending on the combustion state, and the corrected target intake air amount is corrected. In order to obtain, for example, control of a throttle actuator is performed.

It should be noted that the correction according to the target equivalence ratio may be performed and then the correction according to the combustion state may be performed. On the contrary, after the correction according to the combustion state is performed, the target equivalent ratio may be corrected. The correction may be made according to the target equivalence ratio, and the correction may be made at the same time according to the combustion state.
According to the invention described in claim 4, a fuel injection valve for directly injecting fuel into the combustion chamber of the engine, a homogeneous combustion for injecting fuel in an intake stroke, and a stratified combustion for injecting fuel in a compression stroke. Combustion state switching means for switching control of the combustion state, wherein the correction means based on the combustion state corrects the target intake air amount according to the homogeneous combustion and the stratified combustion switched and controlled by the combustion state switching means. did.

According to such a configuration, in a configuration in which the homogeneous combustion and the stratified combustion that enables combustion at an equivalent ratio leaner than the homogeneous combustion are controlled to be switched, even if the homogeneous equivalent and the stratified combustion have the same equivalent ratio, The target intake air amount is corrected according to the difference in the generated torque (combustion efficiency).
In the invention described in claim 5, the correction means based on the combustion state stores in advance two tables, one for homogeneous combustion and one for stratified combustion, as a table of the combustion efficiency correction rate according to the target equivalence ratio. The target intake air amount is corrected based on the combustion efficiency correction rate retrieved from the table corresponding to the combustion state at that time.

  According to this configuration, in the configuration in which the target intake air amount is corrected based on the difference in combustion efficiency due to the target equivalent ratio, two tables, one for homogeneous combustion and the other for stratified combustion, are stored in advance as a table storing the combustion efficiency correction rate. Therefore, even if the target equivalent ratio is the same, a different combustion efficiency correction rate is obtained depending on the table to be referred to, and the target intake air amount is corrected.

In the invention according to claim 6, the correction means based on the combustion state corrects the combustion efficiency correction rate according to the target equivalence ratio with different gains for the homogeneous combustion and the stratified combustion, and the corrected combustion efficiency correction rate The target intake air amount is corrected based on the above.
According to such a configuration, the same combustion efficiency correction rate is set regardless of the combustion state according to the target equivalence ratio. However, the combustion efficiency correction rate according to the target equivalence ratio has different gains for homogeneous combustion and stratified combustion. To correct the target intake air amount, so that the target intake air amount is corrected at a combustion efficiency correction rate that differs depending on whether the combustion is substantially homogeneous or stratified combustion. .

According to a seventh aspect of the present invention, the target intake air amount is calculated based on the target engine torque corrected based on the pumping loss torque corresponding to the target equivalent ratio.
According to this configuration, a different pumping loss torque is added to the target engine torque according to the target equivalent ratio, and the target intake air amount is calculated based on the target engine torque to which the pumping loss torque has been added.

According to the first aspect of the present invention, the target intake air amount corresponding to the target engine torque and the target equivalence ratio is set, so as to cope with the variable control of the target equivalence ratio and the combustion state switching control. Since the target intake air amount is corrected according to the state, it is possible to set the target intake air amount corresponding to the difference in combustion efficiency depending on the combustion state, thereby avoiding the occurrence of a torque step due to switching of the combustion state. There is.

  According to the second aspect of the present invention, in a direct injection engine capable of performing combustion at an ultra-lean equivalent ratio by stratified combustion, a target intake air amount is changed according to switching between homogeneous combustion and stratified combustion accompanying variable control of a target equivalent ratio. Is corrected, and even if the same equivalent ratio is used, even if switching between homogeneous combustion and stratified combustion with different generated torques is performed, there is an effect that generation of a torque step can be avoided.

  According to the third aspect of the present invention, the target intake air amount is calculated so as to obtain the target engine torque and the target torque according to the accelerator operation amount and the engine rotation speed, while the target intake air amount is changed to the combustion state. Since the correction is performed in accordance with the difference, it is possible to set the target intake air amount corresponding to the difference in the combustion efficiency depending on the combustion state, and thus it is possible to avoid the occurrence of the torque step due to the switching of the combustion state.

According to the fourth aspect of the present invention, the target intake air amount is corrected in response to the switching control between the homogeneous combustion and the stratified combustion, so that the homogeneous combustion and the stratification with different generated torques even at the same equivalent ratio. Even if the combustion is switched, there is an effect that generation of a torque step can be avoided.
According to the fifth aspect of the present invention, the target equivalence ratio is retrieved by searching a combustion efficiency correction rate for coping with a difference in combustion efficiency due to a difference in target equivalence ratio between stratified combustion and homogeneous combustion. There is an effect that the target intake air amount can be accurately corrected according to the combustion efficiency in accordance with the difference between stratification and homogeneous combustion.

According to the sixth aspect of the present invention, the correction ratio of the combustion efficiency for coping with the difference in the combustion efficiency due to the difference in the target equivalent ratio is corrected by different gains in the stratified combustion and the homogeneous combustion, so that the target equivalent ratio is corrected. In addition, there is an effect that correction of the target intake air amount for coping with the difference between stratification and homogeneous combustion can be easily performed.
According to the seventh aspect of the present invention, the target intake air amount is calculated based on the target engine torque to which the different pumping loss torque is added according to the target equivalence ratio, so that the target engine torque required by the driver can be accurately calculated. There is an effect that it can be obtained.

Hereinafter, embodiments of the present invention will be described.
FIG. 2 is a system configuration diagram of the engine in the embodiment.
In FIG. 2, an accelerator operation amount sensor 1 as an accelerator operation amount detecting means detects an accelerator operation amount APS corresponding to an accelerator pedal depression amount by the driver as an engine load (engine torque) desired by the driver.

  The crank angle sensor 2 as an engine rotation speed detecting means outputs a position signal POS for each unit crank angle and a reference signal REF for each stroke phase difference between cylinders, and counts the number of the position signals POS generated per unit time. By doing so, or by measuring the generation cycle of the reference signal REF, the engine rotation speed NE can be detected.

The air flow meter 3 detects an intake air amount (intake air amount per unit time = intake air flow rate) Q of the engine 4.
Water temperature sensor 5 detects cooling water temperature TW of engine 4.
The engine 4 is provided with an electromagnetic fuel injection valve 6 that is driven to be opened by an injection pulse signal to directly inject fuel into the combustion chamber, and an ignition plug 7 that is mounted in the combustion chamber and ignites. A throttle valve 9 is interposed in the intake passage 8, and a throttle valve control device 10 for controlling the throttle valve 9 to a target throttle opening by opening and closing the throttle valve 9 with a throttle actuator such as a motor is provided.

  The detection signals from the various sensors are input to a control unit 11 having a built-in microcomputer, and the control unit 11 controls the throttle valve control device 10 according to an operation state detected based on signals from the various sensors. Controls the opening of the throttle valve 9 via the control valve, drives the fuel injection valve 6, controls the fuel supply amount (air-fuel ratio), sets the ignition timing, and ignites the ignition plug 7 at the ignition timing. Perform control.

Here, how the control unit 11 controls the fuel supply amount and the throttle opening degree will be described with reference to the control block diagram of FIG.
The accelerator operation amount APS and the engine rotational speed NE are input to the engine torque equilibrium value calculation unit A, and the engine torque equilibrium value (target engine torque) tTEO is set in advance using the accelerator operation amount APS and the engine rotational speed NE as parameters. An engine torque equilibrium value (target engine torque) tTEO is calculated with reference to the stored map.

  The engine torque balance value (target engine torque) tTEO calculated by the engine torque balance value calculation unit A is input to the target intake air amount calculation unit B, and the engine torque balance value (target engine torque) tTEO and the engine rotation speed are calculated in advance. The target intake air amount TTPO corresponding to the reference equivalence ratio (for example, the stoichiometric air-fuel ratio) is calculated with reference to a map in which the target intake air amount TTPO is stored using NE as a parameter.

As the target intake air amount TTPO, in addition to the intake air amount itself for each intake stroke, a basic fuel injection amount (pulse width) corresponding to the intake air amount for each intake stroke and the air flow meter 3 detect the target intake air amount TTPO. For example, the amount of intake air per unit time may be used.
The engine torque equilibrium value calculator A and the target intake air amount calculator B constitute a target intake air amount calculator in the present embodiment. The unit B may be integrated to calculate the target intake air amount TTPO directly from the accelerator operation amount APS and the engine rotation speed NE.

  On the other hand, similarly to the engine torque equilibrium value calculation unit A, the accelerator operation amount APS and the engine rotation speed NE are also input to the target equivalent ratio calculation unit C, and the accelerator operation amount APS and the engine rotation speed NE are previously determined. The target equivalent ratio tDML is calculated with reference to a map storing the target equivalent ratio tDML as a parameter. The target equivalent ratio tDML is calculated using the accelerator operation amount APS, the engine rotation speed NE, the cooling water temperature, the time after starting, the vehicle speed, the acceleration, the auxiliary equipment load during idling, the master back negative pressure, and the like as parameters. Configuration.

The target equivalent ratio tDML calculated by the target equivalent ratio calculator C is input to the combustion efficiency correction rate calculator D. In addition to the target equivalence ratio tDML, a determination signal indicating whether stratified combustion or homogeneous combustion is selected is input to the combustion efficiency correction rate calculation unit D.
The engine 4 of the present embodiment is provided with the fuel injection valve 6 that injects fuel directly into the combustion chamber as described above, and performs homogeneous combustion by injecting fuel in the intake stroke and fuel in the compression stroke. It is configured to be able to switch between stratified combustion in which combustion at an ultra-lean equivalent ratio is performed by injecting (combustion state switching means), and the target equivalent ratio calculation unit C is based on the control of switching between the homogeneous combustion and the stratified combustion. The equivalence ratio within the equivalence ratio control range in each combustion state is set. In effect, the target equivalence ratio calculation section C sets the target equivalence ratio tDML, as well as homogeneous combustion and stratified combustion. Is to be selected.

  The combustion efficiency correction rate calculation unit D stores two types of tables, that is, a table for homogeneous combustion and a table for stratified combustion as tables in which the combustion efficiency correction rate ITAF is stored in advance according to the target equivalent ratio tDML. . This is because even when the equivalent ratio is the same, the generated torque is different due to the difference in the combustion efficiency between the stratified combustion and the homogeneous combustion, and the stratified combustion is performed for the same target equivalent ratio tDML in the switching control between the stratified fuel and the homogeneous combustion. This is because there is a case where selection is made and a case where homogeneous combustion is selected (see FIG. 9).

Then, one of the two tables is selected from the determination signals of the homogeneous and stratified combustion, and the combustion efficiency correction factor ITAF corresponding to the target equivalent ratio tDML at that time is searched in the selected table.
The combustion efficiency correction rate ITAF is multiplied by a target intake air amount TTPO calculated by the target intake air amount calculation unit B (compensation means based on combustion state), and a target intake air amount TTP1 obtained by the multiplication correction is calculated as follows: Furthermore, the final target intake air amount TTP2 is set by dividing by the target equivalent ratio tDML (correction means based on the target equivalent ratio).

  The target throttle valve opening calculating section E is supplied with the engine rotational speed NE together with the target intake air amount TTP2, and stores a target throttle valve opening TTPS in advance using the target intake air amount TTP2 and the engine rotational speed NE as parameters. , The target throttle valve opening TTPS corresponding to the target intake air amount TTP2 and the engine speed NE at that time is calculated.

The target throttle valve opening TTPS is input to the throttle valve control device 10, and the target intake air amount TTP2 is obtained by controlling a throttle actuator so that the target throttle valve opening TTPS becomes the target throttle valve opening TTPS (suction). Air amount control means).
On the other hand, the actual intake air amount Q detected by the air flow meter 3 and the engine rotation speed NE are input to the basic fuel supply amount calculation unit F, and the basic fuel supply amount corresponding to the reference equivalent ratio (for example, the stoichiometric air-fuel ratio) is input. The quantity (basic injection pulse width) TP is calculated.

  When an intake pressure sensor is provided instead of the air flow meter 3, the basic fuel supply amount (basic injection pulse width) TP is determined based on the intake pressure detected by the intake pressure sensor and the engine rotational speed NE. Alternatively, the basic fuel supply amount TP can be calculated based on the throttle valve opening and the engine speed.

In the correction calculation unit G, the basic fuel supply amount (basic injection pulse width) TP is corrected by the target equivalence ratio tDML, the correction amount TS based on the battery voltage, and the like, and the final fuel supply amount (fuel injection pulse width) TI Is calculated.
The control unit 11 outputs an injection pulse signal having a pulse width corresponding to the fuel supply amount (fuel injection pulse width) TI to the fuel injection valve 6 at an injection timing according to the homogeneous combustion and the stratified combustion.

The flowchart of FIG. 4 shows the control contents shown in the control block diagram of FIG. 3. First, in S1, the target engine torque (engine torque equilibrium value) is determined based on the accelerator operation amount APS and the engine speed NE. ) Calculate tTEO.
In S2, a target equivalent ratio tDML is calculated based on the accelerator operation amount APS and the engine speed NE.

In S3, a target intake air amount TTPO is calculated based on the target engine torque tTEO and the engine rotational speed NE (target intake air amount calculation means).
In S4, it is determined whether or not the engine is in a stratified combustion state. If the engine is in stratified combustion, the process proceeds to S5, where a combustion efficiency correction factor ITAF for stratified combustion is calculated. If so, the program proceeds to S6, where a combustion efficiency correction factor ITAF for homogeneous combustion is calculated.

In S7, the target intake air amount TTPO is multiplied by the combustion efficiency correction rate ITAF to calculate a target intake air amount TTP1 subjected to combustion efficiency correction in accordance with the combustion state and the target equivalent ratio tDML (depending on the combustion state). Correction means).
In S8, the target intake air amount TTP1 is divided by the target equivalent ratio tDML to calculate a target intake air amount TTP2 corresponding to the target equivalent ratio tDML (correction means based on the target equivalent ratio).

In S9, the target throttle valve opening TTPS is calculated based on the target intake air amount TTP2 and the engine speed NE, and the calculated throttle valve opening degree TTPS is output to the throttle valve control device 10 (intake air amount control means).
In S10, the basic fuel supply amount TP is calculated based on the intake air amount Q, the engine speed NE, and the reference equivalence ratio at that time. In S11, the basic fuel supply amount TP is corrected by the target equivalence ratio tDML and the like. To calculate the final fuel supply amount TI. In S12, an injection pulse signal having a pulse width corresponding to the fuel supply amount TI is output to the fuel injection valve 6 at an injection timing according to the homogeneous and stratified combustion.

According to the above configuration, the target intake air amount is corrected in response to the difference in generated torque between homogeneous combustion and stratified combustion even at the same equivalence ratio, so that a torque step occurs when switching from homogeneous combustion to stratified combustion. Can be avoided.
FIG. 5 is a control block diagram showing the second embodiment, and is different from the first embodiment shown in FIG. 3 only in the configuration described below. That is, a pumping loss torque calculating section H for calculating a pumping loss torque (pump loss torque) TpI corresponding to the target equivalent ratio tDML calculated by the target equivalent ratio calculating section C is provided. The calculated pumping loss torque TpI is added to the engine torque equilibrium value (target engine torque) tTEO calculated by the engine torque equilibrium value calculation section, and the target intake air amount is calculated based on the target engine torque TTC after the addition correction. The calculation unit B is configured to calculate the target intake air amount TTPO.

  Here, similarly to the first embodiment shown in FIGS. 3 and 4, the target intake air amount TTPO is corrected according to a target equivalent ratio tDML and a correction based on a combustion efficiency correction rate ITAF. However, since the pumping loss torque TpI is added to the target engine torque tTEO, the correction based on the combustion efficiency correction rate ITAF is corrected by subtracting the pumping loss reduction due to the lean combustion (for example, the correction of the thermal efficiency improvement). ).

The flowchart of FIG. 6 shows the control contents shown in the control block diagram of FIG. 5. First, in S21, an engine torque equilibrium value (target engine torque) tTEO is calculated. In S22, a target equivalent ratio tDML is calculated. Is calculated.
In S23, a pumping loss torque TpI is calculated based on the target equivalent ratio tDML.

In S24, the pumping loss torque TpI is added to the target engine torque tTEO to obtain a corrected target engine torque TTC.
In S25, a target intake air amount TTPO is calculated based on the target engine torque TTC.
In S26, the target intake air amount TTPO is divided by the target equivalent ratio tDML to calculate a target intake air amount TTP1 corresponding to the target equivalent ratio tDML.

In S27, it is determined whether or not stratified combustion is performed. If stratified combustion is performed, the process proceeds to S28, where a combustion efficiency correction factor ITAF for stratified combustion is calculated. If so, the program proceeds to S29, in which a combustion efficiency correction factor ITAF for homogeneous combustion is calculated.
In S30, a target intake air amount TTP2 is calculated by multiplying the target intake air amount TTP1 by the combustion efficiency correction factor ITAF.

In S31, the target throttle valve opening TTPS is calculated based on the target intake air amount TTP2, and the target throttle valve opening TTPS is output to the throttle valve controller 10.
On the other hand, in S41, the basic fuel supply amount TP is calculated, and in the next S42, the basic fuel supply amount TP is corrected by the target equivalent ratio tDML to calculate the final fuel supply amount TI. In S43, it is determined whether or not the injection timing is different depending on the stratified charge combustion and the homogeneous combustion. When the injection timing is reached, an injection pulse signal having a pulse width corresponding to the fuel supply amount TI is sent to the fuel injection valve 6. Output to

FIG. 7 is a control block diagram showing the third embodiment. The following configuration is different from the first embodiment shown in FIG.
That is, the combustion efficiency correction rate calculation unit D is configured to calculate the combustion efficiency correction rate ITAF only from the target equivalent ratio tDML, while the combustion efficiency correction rate ITAF calculated by the combustion efficiency correction rate calculation unit D is used. A stratified / homogeneous gain switching section I is provided for switching the gain Gain to be corrected depending on whether the combustion is homogeneous combustion or stratified combustion. The stratification / homogeneous gain switching section I outputs a gain = 1 during homogeneous combustion and outputs a stratification gain during stratification combustion. The rate ITAF is calculated, and at the time of stratified combustion, the combustion efficiency correction rate ITAF suitable for the homogeneous combustion is corrected by the stratification gain, whereby the combustion efficiency correction rate ITAF suitable for stratified combustion is converted.

The flowchart of FIG. 8 shows the control contents shown in the control block diagram of FIG. 7. First, at S51, an engine torque equilibrium value (target engine torque) tTEO is calculated. At S52, a target equivalent ratio tDML is calculated. Is calculated.
In S53, a target intake air amount TTPO is calculated based on the target engine torque tTEO.

In S54, a combustion efficiency correction rate ITAF is calculated based on the target equivalent ratio tDML.
In S55, it is determined whether or not stratified charge combustion is being performed. If stratified charge combustion is performed, the flow proceeds to S56 to select a stratified combustion efficiency gain. If not stratified charge combustion and homogeneous combustion is performed, control is passed to S57. Select the combustion efficiency gain for homogenization.

In S58, the combustion efficiency correction factor ITAF is corrected according to the gain Gain selected according to the stratification and the homogeneous combustion as described above.
In S59, the target intake air amount TTPO is corrected by the corrected combustion efficiency correction factor ITAF 'to calculate the target intake air amount TTP1.
In S60, the final target intake air amount TTP2 is calculated by dividing the target intake air amount TTP1 by the target equivalent ratio tDML.

In S61, the target throttle valve opening TTPS is calculated based on the engine speed NE and the target intake air amount TTP2, and the target throttle valve opening TTPS is output to the throttle valve controller 10.
In S62, the basic fuel supply amount TP is calculated based on the actual intake air amount Q at that time and the reference equivalent ratio. In S63, the basic fuel supply amount TP is corrected by the target equivalent ratio tDML and the like. To calculate the final fuel supply amount TI. In S64, an injection pulse signal having a pulse width corresponding to the fuel supply amount TI is output to the fuel injection valve 6 at a predetermined timing.

FIG. 4 is a block diagram showing a basic configuration of the invention according to claim 3. FIG. 1 is a system configuration diagram of an engine according to an embodiment. FIG. 2 is a control block diagram illustrating the first embodiment. 4 is a flowchart illustrating a first embodiment. FIG. 6 is a control block diagram showing a second embodiment. 9 is a flowchart illustrating a second embodiment. FIG. 13 is a control block diagram showing a third embodiment. 9 is a flowchart illustrating a third embodiment. FIG. 4 is a diagram showing a difference in fuel efficiency due to a difference between stratified combustion and homogeneous combustion.

Explanation of reference numerals

  DESCRIPTION OF SYMBOLS 1 ... Accelerator operation amount sensor, 2 ... Crank angle sensor, 3 ... Air flow meter, 4 ... Engine, 5 ... Water temperature sensor, 6 ... Fuel injection valve, 9 ... Throttle valve, 10 ... Throttle valve controller, 11 ... Control unit, A: engine torque equilibrium value calculation unit, B: target intake air amount calculation unit, C: target equivalent ratio calculation unit, D: combustion efficiency correction rate calculation unit, E: target throttle valve opening calculation unit, F: basic fuel supply Amount calculation unit, G: correction calculation unit, H: pumping loss torque calculation unit, I: stratification / homogeneous gain switching unit

Claims (7)

  A target intake air amount corresponding to a target engine torque and a target equivalence ratio according to an operation state of the engine is calculated, and the target intake air amount is corrected according to a combustion state, and based on the corrected target intake air amount. An engine torque control device for controlling an intake air amount of an engine by using the torque control device.   A fuel injection valve that injects fuel directly into the combustion chamber of the engine is provided, and is configured to be capable of switching between homogeneous combustion by injecting fuel in an intake stroke and stratified combustion by injecting fuel in a compression stroke, The engine torque control device according to claim 1, wherein the correction of the target intake air amount according to the combustion state is a correction of the target intake air amount according to the homogeneous combustion and the stratified combustion. Accelerator operation amount detection means for detecting an accelerator operation amount;
Engine rotation speed detection means for detecting the engine rotation speed,
Target intake air amount calculating means for calculating a target engine air amount and a target intake air amount corresponding to a reference equivalent ratio according to the detected accelerator operation amount and engine rotation speed;
Correction means for correcting the target intake air amount to a target intake air amount corresponding to the target equivalent ratio in accordance with a target equivalent ratio corresponding to the detected accelerator operation amount and the engine rotation speed;
A combustion state correction means for correcting the target intake air amount according to a combustion state, and an engine intake air amount based on the target intake air amount corrected by the target equivalent ratio correction means and the combustion state correction means. An engine torque control device, comprising: an intake air amount control means for controlling the intake air amount.   A fuel injection valve that injects fuel directly into the combustion chamber of the engine, and a combustion state switching unit that controls switching between homogeneous combustion by injecting fuel in an intake stroke and stratified combustion by injecting fuel in a compression stroke. The correction according to the combustion state, wherein the correction means according to the combustion state corrects the target intake air amount according to the homogeneous combustion and the stratified combustion which are switched and controlled by the combustion state switching means. Engine torque control device.   The correction means based on the combustion state stores in advance two tables, one for homogeneous combustion and the other for stratified combustion, as a table of the combustion efficiency correction rate according to the target equivalence ratio, and stores the combustion state at that time among these two tables. 5. The engine torque control device according to claim 4, wherein the target intake air amount is corrected based on a combustion efficiency correction rate retrieved from a corresponding table.   The combustion state correction means corrects a combustion efficiency correction rate according to the target equivalent ratio with different gains for homogeneous combustion and stratified combustion, and based on the corrected combustion efficiency correction rate, the target intake air amount. The torque control device for an engine according to claim 4, wherein the torque is corrected.   7. The method according to claim 3, wherein the target intake air amount calculating means calculates a target intake air amount based on a target engine torque corrected based on a pumping loss torque corresponding to a target equivalent ratio. The torque control device for an engine according to any one of the preceding claims.

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