JP2015158171A - Cylinder injection engine controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder injection engine controller capable of maximizing transient responsiveness without deteriorating a combustion state in a transient state in which a quantity of intake air increases.SOLUTION: An ECU 50 constituting a cylinder injection engine controller 1 comprises: an additional-air-quantity prediction unit 51 predicting a quantity of additional air to be drawn in additionally to a quantity of intake air detected by an air flow meter 14 if it is assumed that a throttle valve 13 is driven in proportion to depression of an accelerator pedal; a required-additional-injection-quantity computing unit 52 calculating a required additional injection quantity corresponding to the quantity of the additional air; and a possible-additional-injection-quantity acquisition unit 53 acquiring a quantity of possible additional injection that can be additionally injected on the basis of an operating state of an engine 10. A throttle control unit 55 suppresses a valve opening amount of the throttle valve 13 with respect to the depression of the accelerator pedal on the basis of a deviation between the required additional injection quantity and the possible additional injection quantity if the possible additional injection quantity is smaller than the required additional injection quantity.

Description

  The present invention relates to a control device for an in-cylinder injection engine.

  In recent years, in-cylinder injection engines that can improve the charging efficiency and knock resistance by directly injecting fuel into the cylinders of the engine have been widely put into practical use. By the way, in a transient state where the driver suddenly depresses the accelerator pedal greatly and the throttle valve is suddenly opened accordingly, the amount of intake air flowing into the cylinder of the engine suddenly increases. Even if the fuel amount corresponding to the air amount detected by an air flow meter or the like is injected by the injector, the fuel amount may be insufficient. In order to compensate for such a shortage of fuel amount, a technique is known in which additional injection is performed to achieve a target air-fuel ratio (see, for example, Patent Document 1).

  Here, Patent Document 1 discloses a technique (combustion control technique at the time of acceleration) that prevents the occurrence of misfire caused by the accelerator pedal being stepped on rapidly and greatly to increase the intake air amount. More specifically, the in-cylinder injection engine described in Patent Document 1 is an in-cylinder injection engine having a uniform combustion region in which fuel is injected in the intake stroke, and the intake air before and after the start of fuel injection. The intake charge amount is calculated based on the detected value of the amount, the fuel injection amount is determined according to the intake charge amount calculated at the start of injection, and more than the intake charge amount calculated at the time before injection. When the intake charge amount calculated at the time after injection is large, an amount of fuel commensurate with the increase is additionally injected during the first half of the compression stroke. Therefore, according to this in-cylinder injection engine, it is possible to control the combustion state so as to prevent the air-fuel ratio from becoming excessive (lean) due to the increase in the intake charge amount, and further to prevent misfiring of the engine.

JP-A-11-101146

  As described above, according to the in-cylinder injection engine described in Patent Document 1, in the transient state where the accelerator pedal is suddenly depressed greatly and the intake air amount increases, additional injection is performed in the first half of the compression stroke, thereby The lean air-fuel ratio due to the increase in the amount is prevented. However, when fuel is additionally injected in the compression stroke, since the time until the ignition timing is short, depending on the amount of fuel to be additionally injected, the timing of injection, etc., fuel vaporization or mixing with air becomes insufficient, May cause deterioration of combustion.

  The present invention has been made to solve the above problems, and in-cylinder injection capable of maximizing transient response without deteriorating the combustion state in a transient state where the intake air amount increases. An object of the present invention is to provide an engine control device.

  An in-cylinder injection engine control apparatus according to the present invention includes an intake air amount detection unit that detects an amount of air sucked into the engine, an accelerator operation amount detection unit that detects an accelerator operation amount, and an accelerator operation amount detection unit. Assuming that the throttle is driven according to the amount of accelerator operation by the throttle control means for adjusting the intake air amount of the engine by controlling the drive of the throttle according to the detected operation amount of the accelerator. In this case, the additional air amount prediction means for predicting the additional air amount to be additionally sucked with respect to the intake air amount detected by the intake air amount detection means, and the additional air amount prediction based on the target air-fuel ratio Additional required fuel amount calculation means for obtaining an additional required fuel amount corresponding to the additional air amount predicted by the means, and addition based on the operating state of the engine An additional fuel quantity acquisition unit that acquires an additional fuel quantity that can be supplied with respect to the additional required fuel quantity obtained by the fuel quantity calculation unit is provided, and the throttle control unit obtains the additional fuel quantity acquisition unit. When the added fuel amount is smaller than the additional required fuel amount calculated by the additional required fuel amount calculation means, the amount of accelerator operation is determined based on the deviation between the additional required fuel amount and the additional fuel amount. The throttle drive amount is suppressed.

  According to the control apparatus for a direct injection engine according to the present invention, when it is assumed that the throttle is moved in accordance with the movement of the accelerator (operation prediction), the control is added to the intake air amount detected by the intake air amount detecting means. The amount of additional air to be sucked in is estimated, and an amount of fuel (additional required fuel amount) corresponding to all of the additional air amount is obtained. On the other hand, the amount of additional fuel that can be actually supplied is acquired. Then, based on the deviation between the additional required fuel amount and the addable fuel amount, the throttle drive amount is suppressed. That is, a restriction is imposed on the operation of the throttle for an amount that cannot be compensated by the additional injection. As a result, in a transient state where the intake air amount increases, the transient response can be maximized without deteriorating the combustion state.

  The control apparatus for a direct injection engine according to the present invention includes a correcting unit that corrects the addable fuel amount acquired by the addable fuel amount acquiring unit based on an environmental condition of the engine, and the throttle control unit includes the post-correction When the additional fuel amount is smaller than the additional required fuel amount, it is preferable to suppress the drive amount of the throttle based on a deviation between the additional required fuel amount and the corrected additional fuel amount.

  In this case, the amount of fuel that can be added is corrected, and the drive amount of the throttle is suppressed based on the deviation between the fuel amount that can be added and the fuel amount that can be added after the correction. Therefore, the throttle drive amount can be adjusted more appropriately, and the transient response can be further improved.

  The control device for a direct injection engine according to the present invention preferably includes an intake air temperature detecting means for detecting an intake air temperature, and the correction means increases the amount of fuel that can be added as the intake air temperature increases.

  The higher the intake air temperature, the more fuel vaporization is promoted, and as a result, the mixing with intake air is also promoted. Therefore, even if the amount of fuel that can be added is increased, the combustion is unlikely to deteriorate. Therefore, in this case, by increasing the amount of fuel that can be added as the intake air temperature increases, transient response can be further improved without deteriorating the combustion state.

  The control apparatus for a direct injection engine according to the present invention includes index value detection means for detecting an index value having a correlation with the engine temperature, and the correction means can add additional fuel as the engine temperature indicated by the index value increases. Is preferably increased.

  The higher the engine temperature, the more fuel vaporization is promoted. As a result, mixing with intake air is also promoted. Therefore, even if the amount of fuel that can be added is increased, the combustion is unlikely to deteriorate. Therefore, in this case, by increasing the amount of fuel that can be added as the engine temperature increases, transient response can be further improved without deteriorating the combustion state.

  The control apparatus for a direct injection engine according to the present invention preferably includes an atmospheric pressure detection unit that detects an atmospheric pressure, and the correction unit increases the amount of fuel that can be added as the atmospheric pressure increases.

  The higher the atmospheric pressure, the more the mixing with the intake air is promoted. Therefore, even if the amount of fuel that can be added is increased, the combustion is unlikely to deteriorate. Therefore, in this case, by increasing the amount of fuel that can be added as the atmospheric pressure increases, transient response can be further improved without deteriorating the combustion state.

  The control apparatus for a direct injection engine according to the present invention includes fuel property detection means for detecting the fuel property of fuel supplied to the engine, and the correction means is lighter based on the detected fuel property. It is preferable to increase the amount of fuel that can be added.

  The lighter the fuel, the more the fuel vaporization is promoted and, as a result, the mixing with the intake air is promoted. Light fuel has high ignitability and good combustibility. Therefore, even if the amount of fuel that can be added is increased, the combustion is unlikely to deteriorate. Therefore, in this case, by increasing the amount of fuel that can be added as the fuel is lighter, the transient response can be further improved without deteriorating the combustion state.

  The control apparatus for a direct injection engine according to the present invention preferably includes an evaporation concentration detecting means for detecting a fuel evaporative gas concentration, and the correction means increases the amount of fuel that can be added as the fuel evaporative gas concentration decreases.

  When the fuel evaporative gas (evaporation) concentration is high, the air-fuel ratio control tends to become unstable due to the purge of the fuel evaporative gas. Conversely, when the fuel evaporative gas concentration is low, even if the fuel evaporative gas is purged, the air-fuel ratio control is unlikely to become unstable. Therefore, even if the amount of fuel that can be added is increased, the combustion is unlikely to deteriorate. Therefore, in this case, by increasing the amount of fuel that can be added as the fuel evaporative gas concentration decreases, the transient response can be further improved without deteriorating the combustion state.

  The control device for a direct injection engine according to the present invention includes catalyst deterioration detection means for detecting the deterioration degree of the exhaust purification catalyst, and the correction means increases the amount of fuel that can be added as the deterioration degree of the exhaust purification catalyst is lower. It is preferable.

  The lower the degree of deterioration of the exhaust purification catalyst, the higher the exhaust gas purification rate (purification capability). Therefore, in this case, by increasing the amount of fuel that can be added as the degree of deterioration of the exhaust purification catalyst is lower, it is possible to further improve the transient response without deteriorating emissions.

  The control apparatus for a direct injection engine according to the present invention further includes fuel pressure varying means for varying the pressure of fuel injected into the engine based on a deviation between the additional required fuel amount and the corrected additional fuel amount. Is preferred.

  In this case, the amount of fuel that can be added can be increased by increasing the fuel injection pressure and increasing the fuel injection amount per unit time. Therefore, transient response can be further improved. Moreover, since the fuel injected is atomized more by raising the fuel pressure, fuel vaporization can be further promoted.

  The control apparatus for a direct injection engine according to the present invention changes the speed ratio of the continuously variable transmission that converts and outputs the driving force of the engine based on the deviation between the additional required fuel amount and the corrected additional fuel amount. It is preferable to further include shift requesting means for requesting shifting to the low side.

  In this way, by changing the gear ratio of the continuously variable transmission to the low side and increasing the engine rotation range, the drivability associated with the decrease in transient response by suppressing the drive amount of the throttle is achieved. It is possible to compensate for the decline.

  According to the present invention, in a transient state where the intake air amount increases, transient response can be maximized without deteriorating the combustion state.

It is a figure which shows the structure of the control apparatus of the cylinder injection engine which concerns on embodiment. It is the longitudinal cross-sectional view which showed an example of the high pressure fuel pump typically. It is a figure for demonstrating the relationship between the addition request | requirement injection amount, the addition possible injection amount, and the valve-opening suppression amount of a throttle valve. It is a flowchart which shows the process sequence of the additional injection control by the control apparatus of the cylinder injection engine which concerns on embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted.

  First, the configuration of the control device 1 for a direct injection engine according to the embodiment will be described with reference to FIG. FIG. 1 is a diagram showing a configuration of a control device 1 for an in-cylinder injection engine.

  The engine 10 is, for example, a horizontally opposed four-cylinder gasoline engine. The engine 10 is an in-cylinder injection engine that directly injects fuel into a cylinder (in-cylinder). In the engine 10, air sucked from the air cleaner 16 is throttled by an electronically controlled throttle valve (hereinafter simply referred to as “throttle valve”) 13 provided in the intake pipe 15, passes through the intake manifold 11, and enters the engine 10. It is sucked into each formed cylinder. Here, the amount of air sucked from the air cleaner 16 (the amount of air sucked into the engine 10) is an air flow meter 14 (intake air described in claims) disposed between the air cleaner 16 and the throttle valve 13. It is detected by an amount detecting means). A vacuum sensor 30 for detecting the pressure in the intake manifold 11 (intake manifold pressure) is disposed inside the collector portion (surge tank) constituting the intake manifold 11. Further, the throttle valve 13 is provided with a throttle opening sensor 31 that detects the opening of the throttle valve 13.

  In the cylinder head, an intake port 22 and an exhaust port 23 are formed for each cylinder (only one bank is shown in FIG. 1). Each intake port 22 and exhaust port 23 is provided with an intake valve 24 and an exhaust valve 25 for opening and closing the intake port 22 and the exhaust port 23. Between the intake camshaft 28 that drives the intake valve 24 and the intake cam pulley, the intake cam pulley 28 and the intake camshaft 28 are relatively rotated to continuously rotate the rotation phase (displacement angle) of the intake camshaft 28 with respect to the crankshaft 10a. In other words, a variable valve timing mechanism 26 for advancing and retarding the valve timing (opening / closing timing) of the intake valve 24 is provided. The variable valve timing mechanism 26 variably sets the opening / closing timing of the intake valve 24 according to the engine operating state.

  Similarly, between the exhaust camshaft 29 and the exhaust cam pulley, the exhaust cam pulley 29 and the exhaust camshaft 29 are relatively rotated to continuously change the rotation phase (displacement angle) of the exhaust camshaft 29 relative to the crankshaft 10a. A variable valve timing mechanism 27 for advancing and retarding the valve timing (opening / closing timing) of the exhaust valve 25 is provided. The variable valve timing mechanism 27 variably sets the opening / closing timing of the exhaust valve 25 according to the engine operating state.

  Each cylinder of the engine 10 is attached with an injector 12 for injecting fuel into the cylinder. The injector 12 directly injects fuel pressurized by the high-pressure fuel pump 60 into the combustion chamber of each cylinder.

The injector 12 is connected to a delivery pipe (common rail) 61. The delivery pipe 61 distributes the fuel pumped from the high-pressure fuel pump 60 through the fuel pipe 62 to each injector 12. The high-pressure fuel pump 60 boosts the fuel sucked up from a fuel tank (not shown) by a feed pump (low-pressure fuel pump) to a high pressure (for example, 8 to 13 MPa) according to the operating state and supplies the fuel to the delivery pipe 61. . In the present embodiment, the high-pressure fuel pump 60 that is driven by the cam shaft 28 of the engine 10 is used.

  Here, the configuration of the high-pressure fuel pump 60 will be described with reference to FIG. The high-pressure fuel pump 60 mainly includes a cam 601, a lifter 602, a plunger 603, an electromagnetic valve 606 that controls a suction valve 605, and a discharge valve 607. The cam 601 is driven by the rotational power of the cam shaft 28 of the engine 10 to reciprocate the lifter 602 and the plunger 603. When the plunger 603 descends, the intake valve 605 is opened, and fuel flows into the pressurizing chamber 604. When the plunger 603 moves up, the intake valve 605 is closed and the fuel in the pressurized chamber 604 is compressed. The discharge valve 607 is opened by the pressure, and high-pressure fuel is discharged.

  The intake valve 605 has a structure in which the valve closing operation can be electrically controlled by an electromagnetic valve 606. The fuel that has flowed into the pressurizing chamber 604 when the plunger 603 is lowered returns to the suction side when the plunger 603 is raised and the suction valve 605 is held open, and when the suction valve 605 is closed, the pressurization chamber 604 is returned. Is pressurized and discharged. By controlling the timing at which the intake valve 605 is closed when the plunger 603 is raised and changing the ratio of the fuel returned to the intake side and the pressurized fuel, the flow rate discharged at high pressure can be controlled. The solenoid valve 606 is connected to an engine control device (hereinafter referred to as “ECU”) 50 to be described later, and the drive is controlled by the ECU 50.

  Returning to FIG. 1, a canister 70 is connected to a fuel tank (not shown). The fuel evaporative gas (evaporation) accumulated in the upper space of the fuel tank is guided to the canister 70 and temporarily adsorbed by an adsorbent such as activated carbon in the canister 70. The canister 70 is provided with an atmospheric port 71 for introducing outside air. The upper space of the canister 70 is communicated with the intake manifold 11 through the purge passage 72. The purge passage 72 is provided with a variable flow solenoid valve (hereinafter also referred to as “purge solenoid valve”) 73 whose opening degree is adjusted by the ECU 50. When the purge solenoid valve 73 is opened and the negative pressure in the intake manifold 11 acts on the purge passage 72 of the canister 70, air is introduced into the canister 70 from the atmospheric port 71 and is adsorbed by activated carbon or the like in the canister 70. Fuel evaporative gas is desorbed. The desorbed fuel evaporative gas is sucked into the intake manifold 11 of the engine 10 through the purge passage 72 together with the air introduced from the atmospheric port 71.

  A spark plug 17 for igniting the air-fuel mixture and an igniter built-in coil 21 for applying a high voltage to the spark plug 17 are attached to the cylinder head of each cylinder. In each cylinder of the engine 10, an air-fuel mixture of the sucked air and the fuel injected by the injector 12 is ignited by the spark plug 17 and burned. The exhaust gas after combustion is exhausted through the exhaust pipe 18.

An air-fuel ratio sensor 19A that outputs a signal corresponding to the oxygen concentration in the exhaust gas is attached to the exhaust pipe 18. As the air-fuel ratio sensor 19A, a linear air-fuel ratio sensor (LAF sensor) that can detect the exhaust air-fuel ratio linearly is used. As the air-fuel ratio sensor 19A, an O ₂ sensor that detects the exhaust air-fuel ratio on and off may be used.

An exhaust purification catalyst (CAT) 20 is disposed downstream of the air-fuel ratio sensor 19A. The exhaust purification catalyst 20 is a three-way catalyst, which simultaneously oxidizes hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas and reduces nitrogen oxides (NOx) to produce harmful gas components in the exhaust gas. Is purified to harmless carbon dioxide (CO ₂ ), water vapor (H ₂ O) and nitrogen (N ₂ ). A rear (after CAT) O ₂ sensor 19B is provided downstream of the exhaust purification catalyst 20 to detect the exhaust air-fuel ratio on and off.

In addition to the air flow meter 14, the LAF sensor 19 </ _b > A, the O ₂ sensor 19 </ _b > B, the vacuum sensor 30, and the throttle opening sensor 31, a cam angle sensor 32 for determining the cylinder of the engine 10 is provided near the cam shaft of the engine 10. It is attached. A crank angle sensor 33 for detecting the rotational position of the crankshaft 10a is attached in the vicinity of the crankshaft 10a of the engine 10. Here, for example, a timing rotor 33a in which protrusions of 34 teeth with two teeth missing are formed at an interval of 10 ° is attached to the end of the crankshaft 10a, and the crank angle sensor 33 is connected to the timing rotor 33a. The rotational position of the crankshaft 10a is detected by detecting the presence or absence of the protrusion. As the cam angle sensor 32 and the crank angle sensor 33, for example, an electromagnetic pickup type is used.

  These sensors are connected to the ECU 50. Further, the ECU 50 detects the water temperature sensor 34 for detecting the temperature of the cooling water of the engine 10, the oil temperature sensor 35 for detecting the temperature of the lubricating oil, and the depression amount of the accelerator pedal, that is, the opening degree (operation amount) of the accelerator pedal. An accelerator opening sensor 36, an intake air temperature sensor 37 for detecting intake air temperature, an atmospheric pressure sensor 38 for detecting atmospheric pressure, an HC sensor 39 for detecting fuel evaporative gas (evaporation) concentration, and a fuel supplied to the engine 10 Various sensors such as a heavy light sensor 40 for detecting fuel properties (heavy lightness) are also connected. Here, the water temperature sensor 34 (or the oil temperature sensor 35) functions as an index value detecting means described in the claims that detects the water temperature (or oil temperature) as an index value having a correlation with the engine temperature. The accelerator opening sensor 36 functions as an accelerator operation amount detection means, and the intake air temperature sensor 37 functions as an intake air temperature detection means. Further, the atmospheric pressure sensor 38 functions as an atmospheric pressure detection unit, the HC sensor 39 functions as an evaporation concentration detection unit, and the heavy / light sensor 40 functions as a fuel property detection unit.

  Here, as the HC sensor 39, for example, a contact combustion type sensor or a sensor utilizing a change in sound velocity in the detection gas can be used. The fuel evaporative gas (evaporation) concentration may be estimated from the correction amount of the air-fuel ratio feedback when the fuel evaporative gas (evaporation) is actually purged instead of the HC sensor 39. Similarly, the fuel property (heavy / lightness) may be determined based on, for example, the combustion state (combustion fluctuation) immediately after the engine is started instead of the heavy / light sensor 40. This is because lighter fuels with fewer carbons are easier to vaporize and promote mixing with intake air, and lighter fuels are more ignitable and more flammable. The characteristic that the combustion fluctuation immediately after the start-up becomes small is utilized.

  The ECU 50 includes a microprocessor that performs calculations, a ROM that stores programs for causing the microprocessor to execute each process, a RAM that stores various data such as calculation results, and a backup RAM in which the stored contents are held by a 12V battery. And an input / output I / F and the like. The ECU 50 includes an injector driver that drives the injector 12, an output circuit that outputs an ignition signal, a motor driver that drives an electric motor 13 a that opens and closes the electronically controlled throttle valve 13, and the like. The ECU 50 further includes a driver for driving the purge solenoid valve 73, a driver for driving the electromagnetic valve 606 constituting the high-pressure fuel pump 60, and the like.

  In the ECU 50, the cylinder is determined from the output of the cam angle sensor 32, and the engine speed is obtained from the output of the crank angle sensor 33. Further, the ECU 50 determines the intake air amount, the intake pipe negative pressure, the accelerator pedal opening, the air-fuel ratio of the air-fuel mixture, the intake air temperature, the atmospheric pressure, the fuel evaporative gas (based on the detection signals input from the various sensors described above. Various kinds of information such as evaporative concentration, fuel properties (heavyness), and water temperature and oil temperature of the engine 10 are acquired. Then, the ECU 50 comprehensively controls the engine 10 by controlling the fuel injection amount, the ignition timing, and various devices such as the throttle valve 13 based on the acquired various pieces of information.

  In particular, the ECU 50 has a function of maximizing the transient response without deteriorating the combustion state (while maintaining a good combustion state), for example, in a transient state where the intake air amount increases rapidly. Therefore, the ECU 50 includes an additional air amount prediction unit 51, an additional required injection amount calculation unit 52, an addable injection amount acquisition unit 53, an addable injection amount correction unit 54, a throttle control unit 55, a fuel pressure variable unit 56, and a shift request unit 57. And a catalyst deterioration state detection unit 58 is functionally provided. In the ECU 50, the program stored in the ROM is executed by the microprocessor, whereby the additional air amount predicting unit 51, the additional required injection amount calculating unit 52, the addable injection amount acquiring unit 53, and the addable injection amount correcting unit 54. The functions of the throttle control unit 55, the fuel pressure varying unit 56, the shift requesting unit 57, and the catalyst deterioration state detecting unit 58 are realized.

  When it is assumed that the throttle valve 13 is driven in accordance with an accelerator pedal depression amount (operation amount) by a throttle control unit 55 described later, the additional air amount prediction unit 51 sets the intake air amount detected by the air flow meter 14. On the other hand, the amount of additional air that is additionally inhaled is predicted. In other words, when it is assumed that the throttle valve 13 is moved in accordance with the movement of the accelerator pedal (operation prediction), the additional air amount prediction unit 51 takes in the intake air after calculating the fuel injection amount using the detected value of the air flow meter 14. A change in the air amount until the valve 24 is closed is estimated, and an additional air amount to be sucked in addition to the intake air amount detected by the air flow meter 14 is predicted. That is, the additional air amount prediction unit 51 functions as an additional air amount prediction unit described in the claims. The additional air amount predicted by the additional air amount prediction unit 51 is output to the additional required injection amount calculation unit 52.

  The additional required injection amount calculation unit 52 adds the additional required injection amount according to the additional air amount predicted by the additional air amount prediction unit 51 based on the target air-fuel ratio (for example, stoichiometric) (the additional request described in the claims). (Equivalent to the amount of fuel). That is, the additional required injection amount calculation unit 52 functions as an additional required fuel amount calculation unit described in the claims. The additional required injection amount obtained by the additional required injection amount calculation unit 52 is output to the throttle control unit 55.

  The addable injection amount acquisition unit 53 is an additional request obtained by the additional required injection amount calculation unit 52 based on the operating state of the engine 10 (for example, engine speed, ignition timing, valve closing timing of the intake valve 24, etc.). It is determined whether or not all of the injection amount can be injected as additional injection after the intake valve 24 is closed. If not, the additional possible injection amount that can be injected (suppliable) (addable fuel described in the claims) Equivalent to the quantity). That is, the addable injection amount acquisition unit 53 functions as an addable fuel amount acquisition unit described in the claims. The addable injection amount acquired by the addable injection amount acquisition unit 53 is output to the addable injection amount correction unit 54.

  The addable injection amount correction unit 54 corrects the addable injection amount acquired by the addable injection amount acquisition unit 53 based on the environmental condition (environmental factor) of the engine 10. That is, the addable injection amount correction unit 54 functions as a correction unit described in the claims. More specifically, the addable injection amount correction unit 54 increases the addable injection amount as the intake air temperature increases. Further, the addable injection amount correcting unit 54 increases the addable injection amount as the engine temperature indicated by the coolant temperature or the oil temperature (corresponding to the index value described in the claims) becomes higher. Further, the addable injection amount correction unit 54 increases the addable injection amount as the atmospheric pressure increases. Similarly, the addable injection amount correction unit 54 increases the addable injection amount as the fuel is lighter based on the detected fuel property. Further, the addable injection amount correction unit 54 increases the addable injection amount as the fuel evaporative gas (evaporation) concentration decreases. Further, the addable injection amount correction unit 54 increases the addable injection amount as the deterioration degree (degraded state) of the exhaust purification catalyst 20 is lower.

  Here, in the ROM or the like of the ECU 50, the addable injection that defines the relationship between each of the various environmental conditions described above (for example, intake air temperature, water temperature, atmospheric pressure, etc.) and the correction amount (or correction coefficient) of the addable injection amount. Both correction tables are stored in advance. Then, based on each of the detected various environmental conditions, a corresponding addable injection amount correction table is searched to obtain a correction amount (or correction coefficient) of the addable injection amount.

Here, the degree of deterioration (deterioration state) of the exhaust purification catalyst 20 described above is detected by the catalyst deterioration state detection unit 58. That is, the catalyst deterioration state detection unit 58 functions as catalyst deterioration detection means described in the claims. For example, the catalyst deterioration state detection unit 58 changes the output signal of the rear O ₂ sensor 19B after the exhaust purification catalyst 20 with respect to the output signal of the front LAF sensor (or O ₂ sensor) 19A. It is determined that the degree of deterioration of the exhaust purification catalyst 20 is small (as the fluctuation rate is small).

  When the additional required injection amount is larger than the corrected additional injection amount (that is, when the total amount cannot be additionally injected), the additional injection amount is set as the final additional injection amount. Then, at a predetermined additional injection timing (for example, the first half of the compression stroke), additional injection is executed (additional amount of fuel is added). On the other hand, when the additional required injection amount is equal to or smaller than the corrected additional injection amount (that is, when the entire amount can be additionally injected), the additional required injection amount is set as the final additional injection amount. Then, at a predetermined additional injection timing (for example, the first half of the compression stroke), additional injection is executed (additional fuel for the additional required injection amount is added).

  The throttle control unit 55 adjusts the intake air amount of the engine 10 by driving the electric motor 13 a and adjusting the opening degree of the throttle valve 13. The throttle control unit 55 obtains a target throttle opening from, for example, an accelerator opening detected by the accelerator opening sensor 36 during normal operation (when valve-opening suppression control described later is not executed). The electric motor 13a is driven so that the throttle opening matches the actual opening. More specifically, a normal throttle opening map that defines the relationship between the accelerator opening and the throttle opening (the normal relationship) is stored in the ROM or the like of the ECU 50, and this map is based on the accelerator opening. By searching the normal throttle opening map, the target value of the throttle opening is set.

  On the other hand, the throttle control unit 55 determines that the additional required injection amount is larger than the corrected additional injection amount after correction during a transition in which the intake air amount suddenly increases (when the additional required injection amount cannot be additionally injected). Suppresses the valve opening amount (drive amount) of the throttle valve 13 based on the deviation (additional injection impossible amount) between the additional required injection amount and the corrected additional injection amount that can be corrected. That is, the throttle control unit 55 controls the opening degree of the throttle valve 13 so that the rate of change in the opening degree of the throttle valve 13 with respect to the change in the operation amount of the accelerator pedal becomes slow. The throttle control unit 55 functions as throttle control means described in the claims.

  Here, an example of the relationship between the additional required injection amount, the addable injection amount, and the valve opening suppression amount of the throttle valve 13 is shown in FIG. As shown in FIG. 3, when the additional required injection amount is equal to or greater than the corrected additional injection amount (that is, when the total amount cannot be additionally injected), the target throttle opening of the throttle valve 13 is the additional injection amount that can be added. Depending on the setting, it is limited. That is, the opening operation of the throttle valve 13 is restricted with respect to the movement of the accelerator pedal (see the hatched portion in FIG. 3). As a result, an amount of air commensurate with the addable injection amount is inhaled. On the other hand, when the additional required injection amount is equal to or less than the corrected additional injection amount (that is, when the entire amount can be additionally injected), the throttle valve 13 (target throttle opening) is not limited and the accelerator pedal is not limited. The valve is opened according to the movement.

  The fuel pressure variable unit 56 determines the amount of fuel discharged from the high-pressure fuel pump 60 (that is, injected into the engine 10) based on the deviation (additional injection impossible amount) between the additional required injection amount and the corrected additional injection amount that can be corrected. Variable pressure. At this time, the fuel pressure variable unit 52 controls the electromagnetic valve 606 so that the discharge pressure (fuel pressure) of the high-pressure fuel pump 60 increases as the amount of fuel that can be added decreases. That is, the fuel pressure varying unit 52 functions as a fuel pressure varying means described in the claims. In this case, the amount of injection that can be added increases due to the increase in fuel pressure, so that the amount of suppression of the throttle valve 13 is reduced according to the increase amount.

  The speed change request unit 57 converts the driving force of the engine 10 based on the deviation (additional injection impossible amount) between the additional required injection amount and the corrected additional injection amount that can be corrected, and outputs the continuously variable transmission (CVT) 81. Is requested to shift to a low side. That is, the speed change requesting unit 58 controls the speed ratio control of the continuously variable transmission 81 via the CAN 100 so that the speed change ratio of the continuously variable transmission 81 is changed to the low side as the suppression amount of the throttle valve 13 is increased. Requests to the TCU 80 (electronic control unit). That is, the shift request unit 58 functions as a shift request unit described in the claims. The TCU 80 changes the speed ratio of the continuously variable transmission 81 to the low side in response to the speed change request from the speed change request unit 52.

  Next, the operation of the in-cylinder injection engine control device 1 will be described with reference to FIG. FIG. 4 is a flowchart showing a processing procedure of additional injection control by the control device 1 of the in-cylinder injection engine. This process is repeatedly executed in the ECU 50 at a predetermined timing.

  First, in step S100, the operating state and environmental conditions of the engine 10 are detected. That is, the accelerator opening, engine speed, intake air amount, intake air temperature, atmospheric pressure, fuel evaporative gas (evaporation) concentration, fuel properties (heavyness), water temperature, oil temperature, etc. are detected and read. Next, in step S102, a normal fuel injection amount and its injection timing are set based on the operating state of the engine 10 read in step S100.

  Subsequently, in step S104, when it is assumed that the throttle valve 13 is driven in accordance with the depression amount of the accelerator pedal, the intake air amount detected by the air flow meter 14 (the intake air amount read in step S100). Thus, the additional air amount that is additionally sucked in until the intake valve 24 is closed is predicted.

  In the subsequent step S106, an additional required injection amount commensurate with the additional air amount predicted in step S104 is obtained. Subsequently, in step S108, an addable injection amount that can be injected is acquired based on the operating state of the engine 10 with respect to the additional required injection amount obtained in step S106. In step S108, the addable injection amount is corrected based on the environmental conditions of the engine 10 (for example, the intake air temperature, water temperature, atmospheric pressure, etc. described above). Note that the details of the correction of the addable injection amount are as described above, and a detailed description thereof will be omitted here.

  Next, in step S110, a determination is made as to whether or not the additional required injection amount is equal to or less than the corrected additional allowable injection amount, that is, whether or not the additional required injection amount can be additionally injected. Here, when the additional required injection amount is larger than the corrected additional injection amount (that is, when the total amount cannot be additionally injected), the process proceeds to step S112. On the other hand, when the additional required injection amount is equal to or smaller than the corrected additional injection amount (that is, when the entire amount can be additionally injected), the process proceeds to step S116.

  In step S112, the addable injection amount is set as the final additional injection amount. In step S114, the target throttle opening degree of the throttle valve 13 is set in a limited manner according to the addable injection amount. That is, the valve opening operation of the throttle valve 13 is restricted. Further, additional injection is executed (additional amount of fuel corresponding to the additional fuel amount is added) at a predetermined additional injection timing (for example, the first half of the compression stroke). Thereafter, the process is temporarily exited.

  On the other hand, in step S116, the additional required injection amount is set as the final additional injection amount. In step S118, the throttle valve 13 is opened without being restricted. Further, additional injection is executed (additional fuel for the additional required fuel amount) at a predetermined additional injection timing (for example, the first half of the compression stroke). Thereafter, the process is temporarily exited.

  As described above in detail, according to the present embodiment, when it is assumed that the throttle valve 13 is moved in accordance with the movement of the accelerator pedal (operation prediction), the intake air amount detected by the air flow meter 14 is used. In addition, the amount of additional air to be sucked is estimated, and an amount of fuel (additional required injection amount) corresponding to all of the additional air amount is obtained. On the other hand, an addable injection amount that can be injected as additional injection after the intake valve 24 is actually closed is acquired. When the additional required injection amount is larger than the addable injection amount, the valve opening amount of the throttle valve 13 is suppressed based on the deviation between the additional required injection amount and the addable injection amount. That is, a restriction is imposed on the operation of the throttle valve 13 for an amount that cannot be compensated by the additional injection. As a result, it is possible to maximize the transient response without deteriorating the combustion state (while maintaining a good combustion state) in the transient state where the intake air amount rapidly increases. Therefore, fuel consumption, exhaust gas (emission), and output response can be improved.

  According to the present embodiment, the addable injection amount is corrected according to the environmental condition, and the valve opening amount of the throttle valve 13 is controlled based on the deviation between the additional required injection amount and the corrected addable injection amount. . Therefore, the valve opening amount of the throttle valve 13 can be adjusted more appropriately, and the transient response can be further improved.

  More specifically, according to the present embodiment, the addable injection amount increases as the intake air temperature, which is one of the environmental conditions, increases. Here, the higher the intake air temperature is, the more fuel vaporization is promoted, and as a result, mixing with intake air is also promoted. Therefore, even if the amount of fuel that can be added is increased, the combustion is unlikely to deteriorate. Therefore, according to the present embodiment, the transient response can be further enhanced without increasing the combustion state by increasing the amount of fuel that can be added as the intake air temperature increases.

  Further, according to the present embodiment, the addable injection amount increases as the engine temperature indicated by the water temperature (or oil temperature) increases. Here, the higher the engine temperature, the more fuel vaporization is promoted, and as a result, the mixing with intake air is also promoted. Therefore, even if the amount of fuel that can be added is increased, the combustion is unlikely to deteriorate. Therefore, according to the present embodiment, the transient responsiveness can be further enhanced without increasing the combustion state by increasing the amount of fuel that can be added as the engine temperature increases.

  Furthermore, according to the present embodiment, the additional injection amount increases as the atmospheric pressure increases. Here, the higher the atmospheric pressure, the more the mixing with the intake air is promoted. Therefore, even if the amount of fuel that can be added is increased, the combustion is unlikely to deteriorate. Therefore, according to the present embodiment, the transient response can be further improved without increasing the combustion state by increasing the amount of fuel that can be added as the atmospheric pressure increases.

  Similarly, according to the present embodiment, based on the detected fuel property (heavy / lightness), the lighter fuel increases the addable injection amount. Here, the lighter the fuel, the more the vaporization of the fuel is promoted. As a result, the mixing with the intake air is also promoted. Light fuel has high ignitability and good combustibility. Therefore, even if the amount of fuel that can be added is increased, the combustion is unlikely to deteriorate. Therefore, according to the present embodiment, as the proportion of light fuel is higher, the amount of fuel that can be added is increased, thereby making it possible to further improve the transient response without deteriorating the combustion state.

  Further, according to the present embodiment, the addable injection amount increases as the fuel evaporative gas (evaporation) concentration decreases. Here, when the fuel evaporative gas concentration is low, the air-fuel ratio control is less likely to become unstable even if the fuel evaporative gas is purged. Therefore, even if the amount of fuel that can be added is increased, the combustion is unlikely to deteriorate. Therefore, according to the present embodiment, the transient response can be further enhanced without increasing the combustion state by increasing the amount of fuel that can be added as the fuel evaporative gas concentration decreases.

  Furthermore, according to the present embodiment, the lower the degree of deterioration (deterioration state) of the exhaust purification catalyst 20, the greater the injection amount that can be added. Here, the lower the degree of deterioration of the exhaust purification catalyst, the higher the exhaust gas purification rate. Therefore, according to the present embodiment, the transient response can be further improved without increasing the emission by increasing the amount of fuel that can be added as the degree of deterioration of the exhaust purification catalyst decreases.

  Further, according to the present embodiment, the pressure of the fuel injected into the engine 10 is varied based on the deviation between the additional required injection amount and the corrected additional injection amount. Therefore, the amount of fuel that can be added can be increased by increasing the fuel injection pressure and increasing the fuel injection amount per unit time. Therefore, transient response can be further improved. Moreover, since the fuel injected is atomized more by raising the fuel pressure, fuel vaporization can be further promoted.

  Further, according to the present embodiment, the speed ratio of the continuously variable transmission 81 that converts and outputs the driving force of the engine 10 based on the deviation between the additional required injection amount and the corrected addable injection amount is low. The speed is changed. Therefore, by changing the gear ratio of the continuously variable transmission 81 to the low side and increasing the engine rotation region, the driver accompanying a decrease in transient response by suppressing the opening (drive amount) of the throttle 13. It becomes possible to compensate for the decrease in the ability.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made. For example, the environmental condition for correcting the addable injection amount is not limited to the above embodiment. In the above embodiment, the addable injection amount correction table is used when correcting the addable injection amount. However, instead of the addable injection amount correction table, a correction amount (or correction coefficient) is calculated by calculation. It is good.

  Moreover, although the case where the present invention was applied to an in-cylinder injection engine was described as an example in the above embodiment, the present invention can also be applied to an engine that combines in-cylinder injection and port injection. .

DESCRIPTION OF SYMBOLS 1 Control apparatus of cylinder injection engine 10 Engine 12 Injector 13 Electronically controlled throttle valve 14 Air flow meter 19A LAF sensor 19B O ₂ sensor 24 Intake valve 25 Exhaust valve 30 Vacuum sensor 31 Throttle opening sensor 32 Cam angle sensor 33 Crank angle sensor 34 Water temperature sensor 35 Oil temperature sensor 36 Accelerator opening sensor 37 Intake air temperature sensor 38 Atmospheric pressure sensor 39 HC sensor 40 Heavy light sensor 50 ECU
REFERENCE SIGNS LIST 51 additional air amount prediction unit 52 additional required injection amount calculation unit 53 addable injection amount acquisition unit 54 addable injection amount correction unit 55 throttle control unit 56 fuel pressure variable unit 57 shift request unit 58 catalyst deterioration state detection unit 60 high pressure fuel pump 70 Canister 80 TCU
81 continuously variable transmission

Claims (10)

Intake air amount detection means for detecting the amount of air taken into the engine;
An accelerator operation amount detection means for detecting the operation amount of the accelerator;
Throttle control means for adjusting the intake air amount of the engine by controlling the drive of the throttle according to the accelerator operation amount detected by the accelerator operation amount detection means;
When it is assumed that the throttle is driven by the throttle control unit in accordance with the accelerator operation amount, the additional air amount to be sucked in addition to the intake air amount detected by the intake air amount detection unit is predicted. Means for predicting the additional air amount,
An additional required fuel amount calculating means for obtaining an additional required fuel amount according to the additional air amount predicted by the additional air amount predicting means based on a target air-fuel ratio;
An additional possible fuel amount acquisition means for acquiring an additional fuel amount that can be supplied with respect to the additional required fuel amount calculated by the additional required fuel amount calculation means based on an operating state of the engine,
The throttle control unit adds the additional required fuel amount and the additional required fuel amount when the additional required fuel amount acquired by the additional required fuel amount acquiring unit is smaller than the additional required fuel amount calculated by the additional required fuel amount calculating unit. A control apparatus for a direct injection engine, characterized in that a throttle drive amount is suppressed with respect to an accelerator operation amount based on a deviation from a possible fuel amount. Correction means for correcting the addable fuel amount acquired by the addable fuel amount acquisition means based on environmental conditions of the engine;
The throttle control unit suppresses the drive amount of the throttle based on a deviation between the additional required fuel amount and the corrected additional fuel amount when the corrected additional fuel amount is smaller than the additional required fuel amount. The in-cylinder injection engine control device according to claim 1, wherein: Intake temperature detection means for detecting the intake air temperature is provided,
The control device for a direct injection engine according to claim 2, wherein the correction means increases the amount of fuel that can be added as the intake air temperature increases. Comprising an index value detecting means for detecting an index value having a correlation with the engine temperature;
The in-cylinder injection engine control device according to claim 2 or 3, wherein the correction means increases the amount of fuel that can be added as the engine temperature indicated by the index value increases. Equipped with atmospheric pressure detection means for detecting atmospheric pressure,
The in-cylinder injection engine control apparatus according to any one of claims 2 to 4, wherein the correction means increases the amount of fuel that can be added as the atmospheric pressure increases. A fuel property detecting means for detecting the fuel property of the fuel supplied to the engine;
The control of the direct injection engine according to any one of claims 2 to 5, wherein the correction means increases the amount of fuel that can be added as the fuel is lighter based on the detected fuel property. apparatus. Evaporation concentration detection means for detecting the fuel evaporative gas concentration is provided,
The in-cylinder injection engine control device according to any one of claims 2 to 6, wherein the correction means increases the amount of fuel that can be added as the fuel evaporative gas concentration decreases. Equipped with catalyst deterioration detection means for detecting the deterioration degree of the exhaust purification catalyst,
The in-cylinder injection engine control apparatus according to any one of claims 2 to 7, wherein the correction means increases the amount of fuel that can be added as the degree of deterioration of the exhaust purification catalyst decreases.   9. The fuel pressure varying means for varying the pressure of the fuel injected into the engine based on a deviation between the additional required fuel amount and the corrected addable fuel amount. The control apparatus for a cylinder injection engine according to claim 1. Based on the deviation between the additional required fuel amount and the corrected addable fuel amount, a shift request means for requesting to shift the gear ratio of the continuously variable transmission that converts and outputs the driving force of the engine to the low side. The in-cylinder injection engine control device according to any one of claims 2 to 9, further comprising:

Images