JP2010038001A - Fuel injection control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection control device capable of inhibiting the worsening of combustion at the start-up of an internal combustion engine. <P>SOLUTION: An ECU 7 performs injection control of fuel by a PFI 21 for injecting fuel into an air inlet channel 5 and a DI 22 for injecting fuel into a combustion chamber A. The ECU 7 includes a fuel injection amount setting unit 74 for setting a fuel injection amount Q per one cycle. If in-cylinder filling air amount is not in a decreasing state, the ECU 7 performs in-cylinder injection control at the start-up for supplying fuel to an internal combustion engine 1-1, by injecting fuel of the fuel injection amount Q only by the DI 22, immediately after initiating start-up, and performs division injection control at the start-up to the internal combustion engine by injecting fuel of the fuel injection amount Q by the PFI 21, and by injecting the fuel by the DI 22, after the start-up in-cylinder injection control. If in-cylinder filling air amount is in a decreasing state, the ECU 7 performs an air inlet channel injection control at the start-up for supplying fuel to the internal combustion engine 1-1 by injecting the fuel of the fuel injection amount Q only by the PFI 21, immediately after initiating the start-up. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel injection control device, and more specifically, fuel injection control including an intake path fuel injection valve that injects fuel into an intake path of an internal combustion engine and an in-cylinder fuel injection valve that injects fuel into a cylinder of the internal combustion engine. Relates to the device.

  Some fuel injection control apparatuses for internal combustion engines include two fuel injection valves, an intake path fuel injection valve that injects fuel into the intake path and an in-cylinder fuel injection valve that injects fuel into the cylinder. In such a fuel injection control device, a fuel injection amount of fuel per cycle of the internal combustion engine is injected by at least one of the intake path fuel injection valve and the in-cylinder fuel injection valve and supplied to the internal combustion engine. Here, in the fuel injection control by the intake path fuel injection valve and the in-cylinder fuel injection valve at the start of the internal combustion engine, the start-time intake path for injecting fuel of the fuel injection amount set only by the intake path fuel injection valve An injection control and a start-time in-cylinder injection control in which a fuel injection amount set by only the in-cylinder fuel injection valve is injected once in a compression stroke are conceivable.

  Conventionally, as shown in Patent Document 1, when the internal combustion engine is started, the in-cylinder injection control at the start is performed for the first time or several times, and thereafter the intake-path injection control at the start and the in-cylinder injection control at the start are performed. Proposed fuel injection control devices have been proposed. The fuel injection control device shown in Patent Document 1 can optimally balance the HC emission amount and the combustion stability at the time of cold start.

JP 2006-274949 A

  By the way, at the time of starting the internal combustion engine, a fixed fuel injection amount is set based on the temperature of the cooling water circulating through the internal combustion engine at the time of starting and the engine speed. This is because when the engine is started, the rotational speed changes abruptly, so that it is not possible to set the in-cylinder charged air amount that is the amount of air that is filled into the cylinder when starting the internal combustion engine based on the intake air amount. This is because the feedback control of the fuel injection amount based on the air-fuel ratio detected by the A / F sensor cannot be performed because the provided A / F sensor is inactive.

  Here, when fuel is injected by the in-cylinder fuel injection valve, particularly when a set amount of fuel injection is injected at a time in the compression stroke by the in-cylinder fuel injection valve, stratified combustion occurs, so the cylinder is ignited. A stratified mixture is formed in which the air-fuel mixture in the region near the plug is richer than the air-fuel mixture in other regions in the cylinder, so that the air-fuel mixture in the region near the spark plug does not become rich beyond the flammable range. The fuel injection amount is set so that the entire cylinder is lean. That is, when performing the in-cylinder injection control at the start, there is a possibility that the combustion may deteriorate if the rich side is reached.

  Therefore, when performing in-cylinder injection control at the start immediately after the start of the internal combustion engine, the in-cylinder charged air amount, which is the amount of air charged in the cylinder at the start of the internal combustion engine, is the normal cylinder at the start of the internal combustion engine. If the in-cylinder charged air amount is reduced to be smaller than the in-cylinder charged air amount, combustion at the start of the internal combustion engine may be deteriorated.

  Therefore, the present invention has been made in view of the above, and an object of the present invention is to provide a fuel injection control device capable of suppressing deterioration of combustion at the time of starting an internal combustion engine.

  In order to solve the above-described problems and achieve the object, according to the present invention, an intake path fuel injection valve that injects fuel into an intake path of an internal combustion engine and an in-cylinder fuel injection valve that injects fuel into the cylinder of the internal combustion engine The fuel injection control apparatus for performing the fuel injection control according to claim 1, further comprising fuel injection amount setting means for setting a fuel injection amount per cycle of the internal combustion engine, and air filled in the cylinder when the internal combustion engine is started If the in-cylinder charged air amount, which is the amount, is not in a reduced in-cylinder charged air amount that becomes smaller than the normal in-cylinder charged air amount when the internal combustion engine is started, the setting is made immediately after the start of the internal combustion engine. In-cylinder injection control at start-up for supplying the fuel injection amount of fuel to the internal combustion engine by injection by the in-cylinder fuel injection valve is performed, and after the in-cylinder injection control at start-up, the set fuel injection amount A start-time split injection control for supplying an amount of fuel to the internal combustion engine by injection by the intake path fuel injection valve and injection by the in-cylinder fuel injection valve in the compression stroke of the internal combustion engine; When the engine is in a decreasing state, immediately after the start of the internal combustion engine, start-up intake path injection control for supplying the set fuel injection amount of fuel to the internal combustion engine by injection by the intake path fuel injection valve is performed. It is characterized by that.

  The fuel injection control device may further include an injection amount correction unit that corrects the set fuel injection amount, and the injection amount correction unit is configured to perform the start-time in-cylinder injection control and the start-time divided injection control. It is preferable that the fuel injection amount is corrected to decrease in accordance with a decrease in the in-cylinder charged air amount.

  The fuel injection control device according to the present invention switches to start-time intake path injection control when the in-cylinder charged air amount decreases when the start-time in-cylinder injection control is performed immediately after the start of the internal combustion engine. Therefore, even if the in-cylinder injection control is performed immediately after the start of the internal combustion engine, the in-cylinder charged air amount decreases, and the in-cylinder air charging efficiency is higher than the normal in-cylinder air charging efficiency. If the air-fuel ratio in the cylinder becomes rich and the air-fuel mixture in the vicinity of the spark plug may become rich beyond the flammable range due to the in-cylinder injection control at the start, the in-cylinder injection control at the start is Since it prohibits, there exists an effect that it can suppress that the combustion at the time of start-up of an internal combustion engine deteriorates.

  In addition, since the fuel injection control device according to the present invention performs the start-time split injection control after the start-time in-cylinder injection control, the engine speed is increased by first performing the start-time in-cylinder injection control when starting the internal combustion engine. Since the start time division injection control is performed after the intake pressure has dropped, the fuel injected by the intake path fuel injection valve is reliably introduced into the cylinder, and the combustion mode at the start of the internal combustion engine changes from stratified combustion to weak stratified combustion Switch to combustion. Therefore, it is possible to improve fuel efficiency and suppress emission deterioration while ensuring startability.

  In the fuel injection control device according to the present invention, the fuel injection amount in the start-time cylinder injection control and the start-time split injection control is reduced by the injection amount correction means in accordance with the decrease in the cylinder charge air amount. The fuel injected into the cylinder by the fuel injection valve decreases. Therefore, when the air filling efficiency in the cylinder is lower than the normal air filling efficiency in the cylinder and the air-fuel ratio in the cylinder becomes rich, the fuel injected into the cylinder by the cylinder fuel injection valve is reduced. The in-cylinder injection control and the start-time split injection control can suppress the air-fuel mixture in the vicinity of the spark plug from becoming rich beyond the combustible range, and the combustion at the start of the internal combustion engine deteriorates. There is an effect that it can be suppressed.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or that are substantially the same.

[Embodiment 1]
FIG. 1 is a diagram showing a configuration example of an internal combustion engine according to the present invention. As shown in the figure, the internal combustion engine 1-1 according to the first embodiment includes a fuel supply device 2 and a plurality of cylinders 30a to 30d (in-line four cylinders in the first embodiment). 3, a valve device 4, an intake path 5 connected to the internal combustion engine body 3, an exhaust path 6 connected to the internal combustion engine body 3, and an ECU 7 that is a control device that controls the operation of the internal combustion engine 1-1. It is comprised by. Reference numeral 8 denotes an accelerator opening sensor that detects an accelerator opening that is an opening of an accelerator pedal operated by a driver (not shown) and outputs the detected accelerator opening to the ECU 7.

  The fuel supply device 2 supplies fuel stored in the fuel tank 23, for example, gasoline, to the internal combustion engine 1-1. The fuel supply device 2 includes an intake path fuel injection valve 21, an in-cylinder fuel injection valve 22, a fuel tank 23, a PFI fuel pump 24 that is a low-pressure fuel pump, a DI fuel pump 25 that is a high-pressure fuel pump, and a PFI. A PFI fuel pipe 26 connecting the fuel pump 24 and the intake path fuel injection valve 21; a branch pipe 27 connecting the PFI fuel pipe 26 and the DI fuel pump 25; a DI fuel pump 25 and an in-cylinder fuel injection valve 22; The DI fuel pipe 28 and the DI fuel pressure sensor 29 are connected to each other.

  The in-cylinder fuel injection valve 22 (hereinafter, simply referred to as “DI22”) is provided corresponding to each cylinder 30a to 30d of the internal combustion engine body 3, and the in-cylinder of each cylinder 30a to 30d. That is, fuel is supplied to the internal combustion engine 1-1 by injecting fuel in the fuel tank 23 pressurized by the PFI fuel pump 24 and the DI fuel pump 25 into the combustion chamber A, respectively. Each DI 22 is connected to the ECU 7, and control of the fuel injection amount and injection timing by the DI 22, that is, injection control is performed by the ECU 7.

  The intake path fuel injection valve 21 (hereinafter sometimes simply referred to as “PFI21”) is provided corresponding to each cylinder 30a to 30d of the internal combustion engine body 3, and the intake path of the internal combustion engine 1-1. 5. Here, the fuel in the fuel tank 23 pressurized by the PFI fuel pump 24 is injected into the intake port 37 formed in the cylinder head 32 corresponding to each of the cylinders 30a to 30d. -1 is supplied with fuel. Each PFI 21 is connected to the ECU 7, and control of the fuel injection amount and injection timing by the PFI 21, that is, injection control is performed by the ECU 7.

  The fuel tank 23 stores fuel. The fuel stored in the fuel tank 23 is pressurized by the PFI fuel pump 24 and discharged to the PFI fuel pipe 26 as PFI fuel. Therefore, the PFI fuel is supplied to each PFI 21 via the PFI fuel pipe 26 and is supplied to the DI fuel pump 25 via the PFI fuel pipe 26 and the branch pipe 27.

  The DI fuel pump 25 further pressurizes the PFI fuel. The DI fuel pump 25 is driven, for example, by rotation of a pump drive cam (not shown) attached to the intake cam shaft 43 of the valve device 4. The intake camshaft 43 rotates in conjunction with the rotation of the crankshaft 35. That is, the DI fuel pump 25 is driven by the output of the internal combustion engine 1-1.

  The DI fuel pump 25 is provided with an electromagnetic spill valve (not shown). The amount of PFI fuel flowing into the DI fuel pump 25 is adjusted by the electromagnetic spill valve, and pressurized by the DI fuel pump 25. The pressure of the DI fuel discharged to the DI fuel pipe 28 is adjusted. Here, the electromagnetic spill valve is connected to the ECU 7, and the duty ratio is controlled by the ECU 7. Therefore, control of the pressure of DI fuel discharged from the DI fuel pump 25, that is, pressure control is performed by the ECU 7 using an electromagnetic spill valve (not shown).

  The DI fuel pressure sensor 29 is a pressure detection means and detects a DI fuel pressure P that is the pressure of the DI fuel. The DI fuel pressure sensor 29 is provided in the DI fuel pipe 28 and can detect DI fuel pressurized by the DI fuel pump 25 via the DI fuel pipe 28 and supplied to each DI 22. The DI fuel pressure sensor 29 is connected to the ECU 7, and the detected DI fuel pressure P is output to the ECU 7.

  The internal combustion engine body 3 includes a cylinder block 31, a cylinder head 32 fixed to the cylinder block 31, pistons 33 provided corresponding to the cylinders 30a to 30d, connecting rods 34 to be connected, a crankshaft 35, A spark plug 36 is provided for each of the cylinders 30a to 30d. Here, in each of the cylinders 30 a to 30 d of the internal combustion engine body 3, a combustion chamber A is formed by the piston 33, the cylinder block 31, and the cylinder head 32. In the cylinder head 32, an intake port 37 and an exhaust port 38 are formed corresponding to each of the cylinders 30a to 30d, and are connected to the intake path 5 and the exhaust path 6, respectively. Each piston 33 is rotatably supported by a connecting rod 34, and each connecting rod 34 is rotatably supported by a crankshaft 35. In other words, the crankshaft 35 rotates as each piston 33 reciprocates in the cylinder block 31 when the air-fuel mixture composed of the intake air and fuel in the combustion chamber A burns. is there. Each intake port 37 constitutes a part of the intake path 5, and each exhaust port 38 constitutes a part of the exhaust path 6.

  The spark plugs 36 are provided corresponding to the cylinders 30a to 30d, respectively, and ignite and ignite the air-fuel mixture in the combustion chamber A of the cylinders 30a to 30d. Each spark plug 36 is connected to the ECU 7, and control such as ignition timing, that is, ignition control is performed by the ECU 7. Reference numeral 39 denotes a crank angle sensor that detects a crank angle (CA) that is an angle of the crankshaft 35 and outputs the detected crank angle (CA) to the ECU 7. The ECU 7 calculates the engine speed of the internal combustion engine 1-1 from the crank angle detected by the crank angle sensor 39 and determines the cylinder of each of the cylinders 30a to 30d.

  The valve device 4 opens and closes the intake valve 41 and the exhaust valve 42. The valve device 4 includes an intake valve 41 and an exhaust valve 42, an intake camshaft 43, an exhaust camshaft 44, and an intake valve timing mechanism 45 that are provided corresponding to the cylinders 30a to 30d. . Each intake valve 41 is disposed between the intake port 37 and the combustion chamber A, and is opened and closed as the intake camshaft 43 rotates. Each exhaust valve 42 is disposed between the exhaust port 38 and the combustion chamber A, and is opened and closed by the rotation of the exhaust camshaft 44. The intake camshaft 43 and the exhaust camshaft 44 are connected to the crankshaft 35 through transmission means such as a timing chain, and rotate in conjunction with the rotation of the crankshaft 35.

  The intake valve timing mechanism 45 is disposed between the intake camshaft 43 and the crankshaft 35. The intake valve timing mechanism 45 is a continuously variable valve timing mechanism that continuously changes the phase of the intake camshaft 43. The intake valve timing mechanism 45 is connected to the ECU 7, and the ECU 7 performs control of the opening / closing timing of the intake valve 41, that is, valve opening / closing timing control. Further, the valve device 4 is provided with an intake cam position sensor 46, which detects the rotational position of the intake cam shaft 43 and outputs it to the ECU 7. The valve device 4 adjusts the opening / closing timing of the intake valve 41 by the intake valve timing mechanism 45. However, the present invention is not limited to this. For example, an exhaust valve timing mechanism for adjusting the opening / closing timing of the exhaust valve 42 is provided. May also be provided.

  The intake path 5 takes in air from the outside and introduces the drawn air into the combustion chamber A of each cylinder 30 a to 30 d of the internal combustion engine body 3. The intake passage 5 includes an air cleaner 51, an air flow meter 52, a throttle valve 53, and an intake passage 54 that communicates from the air cleaner 51 to the intake ports 37 of the cylinders 30a to 30d. The intake air from which dust has been removed by the air cleaner 51 is introduced into the combustion chambers A of the cylinders 30a to 30d through the intake passages 54 and the intake ports 37. The air flow meter 52 is an intake air amount detection means, which is introduced into each cylinder 30a to 30d, that is, detects the intake air amount sucked from the intake passage 5, and outputs it to the ECU 7. The throttle valve 53 adjusts the amount of intake air taken in from the intake path 5. The throttle valve 53 is driven by an actuator 53a such as a stepping motor. The actuator 53a is connected to the ECU 7, and control of the valve opening of the throttle valve 53, that is, valve opening control is performed by the ECU 7.

  The exhaust path 6 includes a catalyst 61, a silencer (not shown), an exhaust passage 62 communicating from the exhaust port 38 of each cylinder 30a to 30d to the silencer via the catalyst 61, and an A / F sensor 63. It is configured. The catalyst 61 purifies harmful substances such as nitrided oxide (NOx), carbon monoxide (CO), and hydrocarbon (HC) contained in the exhaust gas sucked through the exhaust passage 62. The catalyst 61 can adsorb sulfur (S) contained in the exhaust gas. The sulfur adsorption capacity of the catalyst 61, that is, the maximum sulfur adsorption amount is decreased as the catalyst temperature T increases. The exhaust gas from which harmful substances have been purified is exhausted from the catalyst 61 to the outside through an exhaust passage and a silencer (not shown).

  The A / F sensor 63 is air-fuel ratio detection means, and is disposed upstream of the catalyst 61 in the exhaust passage 62. The A / F sensor 63 detects the exhaust gas air-fuel ratio of the exhaust gas before being sucked into the catalyst 61 out of the exhaust gas exhausted from each combustion chamber A to the exhaust path 6 and outputs it to the ECU 7. . The ECU 7 calculates the air-fuel ratio of the internal combustion engine 1-1, that is, the ratio of air to fuel in the air-fuel mixture in the combustion chamber A based on the exhaust gas air-fuel ratio detected by the A / F sensor 63. That is, the A / F sensor 63 can detect the air-fuel ratio of the internal combustion engine 1-1.

  The ECU 7 operates the internal combustion engine 1-1 by controlling the operation of the internal combustion engine 1-1. The ECU 7 is also a fuel injection control device and executes a fuel injection control method described later. The ECU 7 receives various input signals from sensors attached to various parts of the vehicle on which the internal combustion engine 1-1 is mounted. Specifically, the DI fuel pressure P detected by the DI fuel pressure sensor 29, the crank angle detected by the crank angle sensor 39, the rotational position of the intake cam shaft 43 detected by the intake cam position sensor 46, and the air flow meter 52 The intake air amount detected by the accelerator opening degree, the accelerator opening degree detected by the accelerator opening degree sensor 8, the exhaust gas air-fuel ratio detected by the A / F sensor 63, and the like.

  The ECU 7 outputs various output signals based on these input signals and various maps such as a fuel injection amount map based on the intake air amount and the accelerator opening stored in the storage unit 73. Specifically, an injection signal for performing injection control of each PFI 21 and each DI 22, an ignition signal for performing ignition control of each spark plug 36, an opening / closing timing signal for controlling valve opening / closing timing of the intake valve timing mechanism 45, A valve opening signal for performing valve opening control.

  The ECU 7 includes an input / output unit (I / O) 71 that inputs and outputs the input signal and output signal, a processing unit 72, and a storage unit 73 that stores various maps such as a fuel injection amount map. Has been. The processing unit 72 includes a memory and a CPU (Central Processing Unit). The processing unit 72 includes at least a fuel injection amount setting unit 74, a start-time in-cylinder injection control unit 75, a start-time intake path injection control unit 76, a start-time divided injection control unit 77, and an in-cylinder charged air amount decrease determination. The function as the part 78 is provided. The processing unit 72 realizes the fuel injection control method by the ECU 7 by loading a program based on the operation method of the internal combustion engine 1-1, particularly the fuel injection control method by the ECU 7, and executing the program. Also good. The storage unit 73 is a non-volatile memory such as a flash memory, a memory that can be read only such as a ROM (Read Only Memory), or a memory that can be read and written such as a RAM (Random Access Memory). It can comprise by the combination of these.

  The fuel injection amount setting unit 74 is a fuel injection amount setting means that sets the fuel injection amount per cycle of the internal combustion engine 1-1, that is, the fuel injection amount Q for each of the cylinders 30a to 30d in the first embodiment. is there. That is, the fuel injection amount setting unit 74 sets the fuel injection amount Q by at least one of the PFI 21 and DI 22 corresponding to each of the cylinders 30a to 30d. The fuel injection amount setting unit 74 is basically set based on the engine speed Ne and the detected accelerator opening based on the detected crank angle.

  The start-time in-cylinder injection control unit 75 immediately injects each DI 22 in the compression stroke of the internal combustion engine 1-1 immediately after the start of the internal combustion engine 1-1, thereby setting the fuel set by the fuel injection amount setting unit 74. In-cylinder injection control at start-up, which is injection control for supplying fuel of an injection quantity Q to the internal combustion engine 1-1, is performed. In the first embodiment, the in-cylinder injection control at start-up is an injection control in which fuel of a DI injection amount Q2, which is a set fuel injection amount Q, is supplied to the internal combustion engine 1-1 by a single injection by DI22. The start-time in-cylinder injection control unit 75 also performs ignition control of each spark plug 36, and performs the ignition control so that the ignition timing is advanced with respect to the normal time during the start-time in-cylinder injection control. The start-time in-cylinder injection control unit 75 also performs valve opening control of the throttle valve 53, and at the time of start-up in-cylinder injection control, the valve opening becomes an optimum valve opening for start-up in-cylinder injection control. Thus, the valve opening degree control is performed. The start-time in-cylinder injection control unit 75 sets the injection timing of the DI 22 so that the fuel of the fuel injection amount Q set only by the DI 22 can be injected in the compression stroke of the internal combustion engine 1-1.

  Here, in the first embodiment, the start-time in-cylinder injection control unit 75 starts the start-time in-cylinder injection control when the DI fuel pressure P detected by the DI fuel pressure sensor 29 becomes equal to or higher than a predetermined pressure P1 set in advance. I do. Here, the predetermined pressure P1 is equal to or higher than a pressure at which at least the fuel of the set fuel injection amount Q can be injected by each DI 22 at the time of starting in-cylinder injection control. In other words, the start-time in-cylinder injection control unit 75 starts the start of the internal combustion engine 1-1 when the DI 22 can inject fuel of the fuel injection amount Q set at the time of start-up in-cylinder injection control. In-cylinder injection control at the start is performed assuming that it is immediately after.

  The start-time intake passage injection control unit 76 injects only the PFI 21 immediately after the start of the internal combustion engine 1-1, thereby supplying the fuel with the fuel injection amount Q set by the fuel injection amount setting unit 74 to the internal combustion engine 1. Intake start injection path injection control, which is injection control supplied to -1, is performed. In the first embodiment, the start-time intake path injection control is an injection control in which fuel of a PFI injection amount Q1, which is a set fuel injection amount Q, is supplied to the internal combustion engine 1-1 by a single injection by the PFI 21. The starting intake path injection control unit 76 also performs ignition control of each spark plug 36. The start-time intake path injection control unit 76 also controls the valve opening of the throttle valve 53, and at the time of start-up intake path injection control, the valve opening becomes an optimal valve opening for start-up in-cylinder injection control. Thus, the valve opening degree control is performed. The start-time intake path injection control unit 76 sets the injection timing of the PFI 21 so that the fuel of the fuel injection amount Q set only by the PFI 21 can be injected. Each PFI 21 is injected, for example, in the intake stroke of the internal combustion engine 1-1.

  After the start-time in-cylinder injection control by the start-time in-cylinder injection control unit 75, the start-time divided injection control unit 77 injects each PFI 21 in the intake stroke, for example, and each DI 22 in the compression stroke. Thus, the start time division injection control which is the injection control for supplying the fuel of the fuel injection amount Q set by the fuel injection amount setting unit 74 to the internal combustion engine 1-1 is performed. That is, the start-time division injection control is injection control in which fuel of the set fuel injection amount Q is divided and injected by the PFI 21 and DI 22. In the first embodiment, the start time division injection control is the internal combustion engine 1-1 in which the fuel of the PFI injection amount Q1, which is the fuel injection amount corresponding to the PFI 21, of the set fuel injection amount Q is injected once by the PFI 21. And the fuel of the DI injection amount Q2, which is the fuel injection amount corresponding to DI22 among the set fuel injection amount Q, is supplied to the internal combustion engine 1-1 by one injection by DI22. The start time division injection control unit 77 also performs ignition control of each spark plug 36, and performs ignition control so that the ignition timing is advanced with respect to the normal time during start time division injection control. The start-time split injection control unit 77 also controls the valve opening of the throttle valve 53. During the start-time split injection control, the valve opening is set so that the valve opening becomes an optimal valve opening for the start-time split injection control. The opening degree is controlled. The start time division injection control unit 77 sets the injection timing of each PFI 21 so that the fuel of the PFI injection amount Q1 can reach each combustion chamber A by the PFI 21 in the intake stroke of the internal combustion engine 1-1, and also the internal combustion engine. The injection timing of DI 22 is set so that DI 22 can inject fuel of DI injection amount Q2 in the compression stroke 1-1.

  Here, in the first embodiment, when the switching condition is satisfied, the start time division injection control unit 77 switches from the start time in-cylinder injection control to the start time division injection control and performs the start time division injection control. Here, the switching condition is set based on at least one of the intake pressure in the intake passage 5 (in-cylinder pressure in each combustion chamber A) and the physical quantity that affects the intake pressure. In the first embodiment, the engine speed of the internal combustion engine 1-1, which is a physical quantity that affects the intake pressure, is used as the switching condition, and switching is performed when the detected engine speed Ne is equal to or higher than the first predetermined speed Ne1. Suppose the condition is met. Note that the physical quantity that affects the intake pressure is not limited to the engine speed, but depends on the number of fuel injections of DI 22 (the engine speed increases and the intake pressure decreases as the number of injections increases), and DI 22 It may be an elapsed time from the start of fuel injection (with the passage of time, the number of injections increases, the engine speed increases, and the intake pressure decreases). In this case, it is assumed that the switching condition is satisfied when the number of injections is equal to or greater than the first predetermined number of injections or when the first predetermined time or more has elapsed from the start of fuel injection by the DI 22. Here, at the first predetermined rotation speed, the first predetermined number of injections, and the first predetermined time, the negative pressure is sufficiently generated in the intake passage 5, and the fuel injected by each PFI 21 flows into each combustion chamber A. Is set to a value that can be. The switching condition may be satisfied when the plurality of conditions are satisfied.

  The in-cylinder charged air amount decrease determination unit 78 determines whether or not the in-cylinder charged air amount is reduced when the internal combustion engine 1-1 is started. When the internal combustion engine 1-1 is started, the cylinder charge air amount decrease determination unit 78 is configured so that the cylinder charge air amount that is the amount of air charged into the combustion chamber A is normal when the internal combustion engine 1-1 is started. Whether or not the in-cylinder charged air amount is reduced is determined when the internal combustion engine 1-1 is started, based on whether or not the in-cylinder charged air amount is in a reduced state that is smaller than the in-cylinder charged air amount. In Embodiment 1, the cylinder charge air amount decrease determination unit 78 starts the internal combustion engine 1-1 based on the opening / closing timing of the intake valve 41 based on the detected rotational position of the intake camshaft 43, in particular, the closing timing. It is sometimes determined whether or not the in-cylinder charged air amount is reduced. Here, the normal closing timing of the intake valve 41 at the start of the internal combustion engine 1-1 is the retarded side from the bottom dead center of the piston 33 (the most retarded angle of the intake valve timing mechanism 45 (the intake valve is opened most slowly). Therefore, if the closing timing of the intake valve 41 is retarded from the normal closing timing, the air charging efficiency in the cylinder is normal air filling in the cylinder. Lower than efficiency. That is, when the internal combustion engine 1-1 is started, if the closing timing of the intake valve 41 is retarded with respect to the reference closing timing, which is the normal closing timing, the cylinder air charge amount is increased when the internal combustion engine 1-1 is started. When the internal combustion engine 1-1 is started, it becomes less than the normal in-cylinder charged air amount. Accordingly, the cylinder charge air amount decrease determination unit 78 determines that the closing timing of the intake valve 41 based on the rotational position of the intake camshaft 43 detected at the start of the internal combustion engine 1-1 is a first predetermined value with respect to the reference closing timing. If the value is on the retard side more than the value, it is determined that the internal combustion engine 1-1 is in the in-cylinder charged air amount decreasing state. Here, the first predetermined value is a value with which there is a possibility that the internal combustion engine 1-1 cannot be started by the in-cylinder injection control at the start immediately after the internal combustion engine 1-1 is started.

  Next, an operation method of the internal combustion engine 1-1 according to the first embodiment, that is, a fuel injection control method by the ECU 7 which is a fuel injection control device will be described. FIG. 2 is a diagram illustrating an operation flow of the fuel injection control apparatus according to the first embodiment. In addition, the fuel injection control method by ECU7 is performed for every control period of ECU7.

  First, as shown in FIG. 2, the processing unit 72 of the ECU 7 determines whether or not there is a request for starting the internal combustion engine 1-1 (step ST101). Here, for example, the processing unit 72 determines whether or not there is a request for starting the internal combustion engine 1-1 by turning on / off an ignition (start switch) (not shown) by the driver.

  Next, when determining that there is a request for starting the internal combustion engine 1-1 (Yes in Step ST101), the processing unit 72 starts increasing the pressure of DI fuel (Step ST102). Here, the processing unit 72 first drives and controls a starter (not shown) (electric motor in the case of a hybrid vehicle) to forcibly rotate the internal combustion engine 1-1 in which the starter and the crankshaft 35 are connected. As a result, the DI fuel pump 25 is driven. Next, the processing unit 72 controls the pressure of the DI fuel pump 25 to be driven (controls an electromagnetic spill valve (not shown) with a constant duty ratio), pressurizes the PFI fuel by the DI fuel pump 25, and supplies the DI fuel pipe 28. Discharge and pressurize DI fuel. Here, the pressure increase of the DI fuel is detected by the crank angle sensor 39 and is performed before the crank angle of the internal combustion engine 1-1 is determined, and the DI fuel is quickly started from the start of rotation by the starter of the internal combustion engine 1-1 for starting. Increase pressure. If the processing unit 72 determines that there is no request for starting the internal combustion engine 1-1 (No in step ST101), the processing unit 72 ends the current control cycle and shifts to the next control cycle.

  Next, in-cylinder charged air amount decrease determination unit 78 determines whether or not the in-cylinder charged air amount decrease state is in effect (step ST103). Here, the cylinder charge air amount decrease determination unit 78 is detected by the intake cam position sensor 46, and based on the rotational position of the intake cam shaft 43 acquired by the ECU 7, the closing timing of the intake valve 41 acquired by the ECU 7 Is determined to be on the retard side of the first predetermined value or more with respect to the reference closing timing, thereby determining whether or not the in-cylinder charged air amount is being reduced when the internal combustion engine 1-1 is started. .

  Next, when the in-cylinder charged air amount decrease determination unit 78 determines that the in-cylinder charged air amount decrease determination unit 78 determines that the in-cylinder charged air amount decreases (step ST103 affirmative), the in-start intake route injection control unit 76 Perform (step ST104). Here, the start-time intake path injection control unit 76 supplies the fuel of the PFI injection amount Q1, which is the fuel injection amount Q set by the fuel injection amount setting unit 74, to the internal combustion engine 1-1 by one injection by each PFI 21. Perform injection control. Therefore, a homogeneous mixture is generated in each combustion chamber A, homogeneous combustion is performed, and the engine speed Ne of the internal combustion engine 1-1 is increased by an explosion in each combustion chamber A. Note that when the start-time intake path injection control unit 76 performs the start-time intake path injection control, the processing unit 72 ends the current control cycle and shifts to the next control cycle.

  Further, when the processing unit 72 determines that the in-cylinder charged air amount decrease determining unit 78 is not in the in-cylinder charged air amount decreasing state (No in step STST103), the processing unit 72 determines whether the DI fuel pressure P is equal to or higher than the predetermined pressure P1. (Step ST105). Here, the processing unit 72 starts the start of the internal combustion engine 1-1 by determining whether or not the DI fuel pressure P detected by the DI fuel pressure sensor 29 and acquired by the ECU 7 is equal to or higher than a predetermined pressure P1. It is determined whether it is immediately after. If the processing unit 72 determines that the DI fuel pressure P is less than the predetermined pressure P1 (No in step ST105), the processing unit 72 increases the DI fuel by the DI fuel pump 25 until the DI fuel pressure P becomes equal to or higher than the predetermined pressure P1. To do.

  Next, when the processing unit 72 determines that the DI fuel pressure P is equal to or higher than the predetermined pressure P1 (Yes in Step ST105), the processing unit 72 determines whether or not a switching condition is satisfied (Step ST106). Here, the processing unit 72 determines whether or not the switching condition is satisfied by determining whether or not the detected engine speed Ne is equal to or greater than the first predetermined speed Ne1.

  Next, when it is determined that the switching condition is not satisfied (No in step ST106), the start-time in-cylinder injection control unit 75 performs start-time in-cylinder injection control (step ST107). Here, the in-cylinder injection control unit 75 is not in the in-cylinder charged air amount decreasing state by the in-cylinder charged air amount decrease determining unit 78, that is, in the normal time, immediately after the start of the internal combustion engine 1-1. Perform injection control. The start-time in-cylinder injection control unit 75 determines that the DI fuel pressure P is equal to or higher than the predetermined pressure P1 and the switching condition is not satisfied, that is, the detected engine speed Ne is less than the first predetermined speed Ne1. In-cylinder injection control is performed at start-up. In other words, the start-time in-cylinder injection control unit 75 injects the fuel of the DI injection amount Q2 that is the fuel injection amount Q set by the fuel injection amount setting unit 74 by each DI 22 in the compression stroke of the internal combustion engine 1-1. The injection control supplied to the internal combustion engine 1-1 is performed. Therefore, a stratified mixture is generated in each combustion chamber A, stratified combustion is performed, and the engine speed Ne of the internal combustion engine 1-1 is increased by an explosion in each combustion chamber A. Note that when the start-time in-cylinder injection control unit 75 performs the start-time in-cylinder injection control, the processing unit 72 ends the current control cycle and shifts to the next control cycle.

  Further, when it is determined that the switching condition is satisfied (Yes in step ST106), the start time division injection control unit 77 performs start time division injection control (step ST108). Here, the start time division injection control unit 77 supplies the fuel of the PFI injection amount Q1 to the internal combustion engine 1-1 by one injection by each PFI 21, and compresses the fuel of the DI injection amount Q2 of the internal combustion engine 1-1. Injection control is performed to supply the internal combustion engine 1-1 with a single injection by each DI 22 in the stroke. Accordingly, in each combustion chamber A, the fuel mixture injected by the PFI 21 and the fuel injected by the DI 22 cause the air-fuel mixture in the vicinity of the spark plug 36 to be richer than the other air-fuel mixture in the combustion chamber A. However, a weakly stratified mixture that is weak in the entire combustion chamber A (the mixture in the vicinity of the spark plug 36 is richer than the homogeneous mixture, and the mixture in other regions in the combustion chamber A is more mixed than the stratified mixture) The gas is on the lean side), weak stratified combustion is performed, and the engine speed Ne of the internal combustion engine 1-1 is increased by the explosion in each combustion chamber A. Note that when the start time division injection control unit 77 performs the start time division injection control, the processing unit 72 ends the current control cycle and shifts to the next control cycle.

  As described above, in the ECU 7 that is the fuel injection control device according to the first embodiment, when performing the start-time in-cylinder injection control by the start-time in-cylinder injection control unit 75 immediately after the start of the internal combustion engine 1-1, If the in-cylinder charged air amount decreases when the internal combustion engine 1-1 is started, the control is switched to start-time intake path injection control by the start-time intake path injection control unit 76. Accordingly, even when the start-time in-cylinder injection control unit 75 performs the start-time in-cylinder injection control immediately after the start of the internal combustion engine 1-1, the in-cylinder charged air amount is reduced, and the in-cylinder air charge is reduced. Efficiency is lower than normal in-cylinder air filling efficiency, the air-fuel ratio in the cylinder becomes rich, and the air-fuel mixture in the vicinity of the spark plug may become rich beyond the flammable range by in-cylinder injection control at start-up In this case, since the in-cylinder injection control at the start is prohibited, it is possible to suppress the deterioration of the combustion at the start of the internal combustion engine 1-1.

  If the in-cylinder charged air amount is not reduced at the time of starting the internal combustion engine 1-1, the engine speed Ne is first increased by performing the in-cylinder injection control at the time of starting the internal combustion engine 1-1, and the intake pressure is increased. Is reduced, that is, after the in-cylinder negative pressure is increased, the starting time-division injection control is performed. Therefore, the fuel injected by the PFI 21 is reliably introduced into the combustion chamber A, and together with the fuel injected by the DI 22, the combustion chamber A weakly stratified air-fuel mixture can be generated in A, and the combustion mode at the start of the internal combustion engine 1-1 is switched from stratified combustion to weakly stratified combustion. Therefore, when the spark plug 36 is ignited, the air-fuel mixture in the vicinity of the spark plug 36 is reliably ignited, and the air-fuel mixture in the entire combustion chamber A can be reliably combusted. As a result, the air-fuel mixture in the vicinity of the spark plug 36 can be prevented from becoming richer beyond the combustible range, so that the air-fuel mixture in the entire combustion chamber A can be prevented from becoming leaner, and HC (hydrocarbon) The increase in the emission of can be suppressed. In addition, since the fuel of the set fuel injection amount is divided and injected into each PFI 21 and DI 22, the increase in piston wet can be suppressed and the emission deteriorated compared to the case of only the in-cylinder injection control at the start. Here, an increase in the emission of smoke (black smoke) can be suppressed. Further, compared to the case of only the in-cylinder injection control at the time of starting, a decrease in the pressure of the fuel supplied to the DI 22 can be suppressed, and the fuel of the DI injection amount Q2 is surely secured by the DI 22 at the time of starting divided injection control. Can be injected. Further, at the time of starting split injection control, fuel of the set fuel injection amount Q is divided and injected by the PFI 21 and DI 22, so that the mist in the heavy fuel is compared with the case of starting intake path injection control alone. The influence by deterioration of vaporization and vaporization can be suppressed, and the increase in port wet can be suppressed. Accordingly, it is possible to improve fuel efficiency and suppress emission deterioration while ensuring startability.

  In addition, when fuel is divided and injected into PFI 21 and DI 22 by the start time division injection control, the fuel is injected only by DI 22 by the start time cylinder injection control instead of performing the start time division injection control after the start time cylinder injection control. Compared with the case where the actual fuel injection amount is varied, the torque generated in the internal combustion engine 1-1 with respect to the fuel injection amount even if the actual fuel injection amount fluctuates (eg, about ± 20%) with respect to the set fuel injection amount Q Fluctuations can be suppressed, and an increase in HC (hydrocarbon) emissions can be suppressed. Therefore, robustness can be improved.

[Embodiment 2]
Next, an internal combustion engine 1-2 according to the second embodiment will be described. FIG. 3 is a diagram illustrating a configuration example of the internal combustion engine according to the second embodiment. The internal combustion engine 1-2 according to the second embodiment shown in FIG. 3 is different from the internal combustion engine 1-1 according to the first embodiment shown in FIG. 1 in that the in-cylinder injection control at the start time and the start time division injection are performed. In the control, the fuel injection amount Q is corrected to decrease with a decrease in the cylinder charge air amount. Here, in the basic configuration of the internal combustion engine 1-2 according to the second embodiment, the description of the same parts as the basic configuration of the internal combustion engine 1-1 according to the first embodiment shown in FIG. 1 is omitted.

  As shown in FIG. 3, the injection amount correction unit 79 is an injection amount correction unit. The injection amount correction unit 79 corrects the fuel injection amount Q set by the fuel injection amount setting unit 74 to decrease. In the second embodiment, the injection amount correction unit 79 is configured to perform the internal combustion engine 1-2 during the start-time in-cylinder injection control by the start-time in-cylinder injection control unit 75 and the start-time split injection control by the start-time split injection control unit 77. The set fuel injection amount Q is corrected to decrease based on at least one of the atmospheric pressure at the time of starting and the opening / closing timing of the intake valve 41. Here, when the atmospheric pressure at the time of starting of the internal combustion engine 1-1 is reduced, the amount of air charged in the cylinder is reduced even if the internal combustion engine 1-2 is under the same start condition. In addition, when the internal combustion engine 1-2 is started, if the closing timing of the intake valve 41 is retarded with respect to the reference closing timing, which is the normal closing timing, the amount of air charged in the cylinder decreases as described above. Become. Therefore, for example, the injection amount correction unit 79 uses the atmospheric pressure in the lowland as the reference atmospheric pressure, and the atmospheric pressure at the start of the internal combustion engine 1-2 decreases with respect to the reference atmospheric pressure, or the internal combustion engine 1-2 starts. Sometimes, the fuel injection amount Q, which is set so that the fuel injection amount Q is decreased, is corrected to decrease in accordance with any one of the closing timing of the intake valve 41 being less than the first predetermined value with respect to the reference closing timing. The ECU 7 is provided, for example, outside the internal combustion engine 1-2, is detected by a pressure sensor that detects atmospheric pressure, and is output to the ECU 7 to acquire the atmospheric pressure.

  Next, an operation method of the internal combustion engine 1-2 according to the second embodiment, particularly a fuel injection control method by the ECU 7 which is a fuel injection control device will be described. FIG. 4 is a diagram illustrating an operation flow of the fuel injection control apparatus according to the second embodiment. Of the fuel injection control method according to the second embodiment shown in FIG. 4, the same or substantially the same part as the fuel injection control method according to the first embodiment shown in FIG.

  First, as shown in FIG. 4, the processing unit 72 of the ECU 7 determines whether or not there is a request for starting the internal combustion engine 1-2 (step ST201).

  Next, when it is determined that there is a request for starting the internal combustion engine 1-2 (Yes in Step ST201), the processing unit 72 starts boosting DI fuel (Step ST202). If the processing unit 72 determines that there is no request for starting the internal combustion engine 1-2 (No in step ST201), the processing unit 72 ends the current control cycle and shifts to the next control cycle.

  Next, in-cylinder charged air amount decrease determination unit 78 determines whether or not the in-cylinder charged air amount decreases state (step ST203).

  Next, when the in-cylinder charged air amount decrease determining unit 78 determines that the in-cylinder charged air amount decrease determining unit 78 determines that the in-cylinder charged air amount is in a reduced state (Yes in step ST203), the in-start intake route injection control unit 76 Perform (step ST204). Note that when the start-time intake path injection control unit 76 performs the start-time intake path injection control, the processing unit 72 ends the current control cycle and shifts to the next control cycle.

  In addition, when the processing unit 72 determines that the in-cylinder charged air amount decrease determining unit 78 is not in the in-cylinder charged air amount decreasing state (No in step ST203), the processing unit 72 determines whether the DI fuel pressure P is equal to or higher than the predetermined pressure P1. (Step ST205). If the processing unit 72 determines that the DI fuel pressure P is less than the predetermined pressure P1 (No in step ST205), the processing unit 72 increases the DI fuel by the DI fuel pump 25 until the DI fuel pressure P becomes equal to or higher than the predetermined pressure P1. To do.

  Next, when determining that the DI fuel pressure P is equal to or higher than the predetermined pressure P1 (Yes in Step ST205), the processing unit 72 determines whether or not the switching condition is satisfied (Step ST206).

  Next, when it is determined that the switching condition is not satisfied (No in step ST205), the injection amount correction unit 79 corrects the fuel injection amount Q based on the in-cylinder charged air amount (step ST207). Here, as described above, the injection amount correction unit 79 sets the fuel injection amount Q that is set based on at least one of the atmospheric pressure at the start of the internal combustion engine 1-2 or the opening / closing timing of the intake valve 41. Correct the decrease.

  Next, the start-time in-cylinder injection control unit 75 performs start-time in-cylinder injection control (step ST208). Here, the in-cylinder injection control unit 75 is not in the in-cylinder charged air amount decreasing state by the in-cylinder charged air amount decrease determining unit 78, that is, in the normal time immediately after the start of the internal combustion engine 1-2 is started. Perform injection control. The start-time in-cylinder injection control unit 75 determines that the DI fuel pressure P is equal to or higher than the predetermined pressure P1 and the switching condition is not satisfied, that is, the detected engine speed Ne is less than the first predetermined speed Ne1. In-cylinder injection control is performed at start-up. That is, the in-cylinder injection control unit 75 at the time of start DI is the fuel injection amount Q that has been corrected to decrease by the injection amount correction unit 79 (the fuel injection amount that is equal to or less than the fuel injection amount Q set by the fuel injection amount setting unit 74). Injection control is performed to supply the fuel of the injection amount Q2 to the internal combustion engine 1-2 by one injection by each DI 22 in the compression stroke of the internal combustion engine 1-2. Therefore, the fuel injected into the cylinder, that is, into the fuel chamber A by the DI 22 during the in-cylinder injection control at the start-up decreases in accordance with the decrease in the in-cylinder charged air amount. Note that when the start-time in-cylinder injection control unit 75 performs the start-time in-cylinder injection control, the processing unit 72 ends the current control cycle and shifts to the next control cycle.

  Further, when it is determined that the switching condition is satisfied (Yes in step ST206), the injection amount correction unit 79 corrects the fuel injection amount Q based on the in-cylinder charged air amount (step ST209). Here, as described above, the injection amount correction unit 79 sets the fuel injection amount Q that is set based on at least one of the atmospheric pressure at the start of the internal combustion engine 1-2 or the opening / closing timing of the intake valve 41. Correct the decrease.

  Further, the start time division injection control unit 77 performs start time division injection control (step ST210). Here, the start-time divided injection control unit 77 is not in the in-cylinder charged air amount decreasing state by the in-cylinder charged air amount decrease determining unit 78, that is, performs the start-time divided injection control after the start-time in-cylinder injection control. The start time division injection control unit 77 supplies the fuel of the PFI injection amount Q1 out of the fuel injection amount Q corrected for decrease to the internal combustion engine 1-2 by one injection by each PFI 21, and the corrected fuel injection amount Q Among these, the injection control is performed to supply the fuel of the DI injection amount Q2 to the internal combustion engine 1-2 by one injection by each DI 22 in the compression stroke of the internal combustion engine 1-2. Accordingly, the fuel injected into the cylinder, that is, into the fuel chamber A by the DI 22 during the start time division injection control is decreased in accordance with the decrease in the cylinder filled air amount. Note that when the start time division injection control unit 77 performs the start time division injection control, the processing unit 72 ends the current control cycle and shifts to the next control cycle.

  As described above, the ECU 7 that is the fuel injection control device according to the second embodiment has the same effects as those of the first embodiment, and the injection amount correction unit 79 performs the start-time in-cylinder injection control and the start-time divided injection. Since the fuel injection amount Q in the control decreases in accordance with the decrease in the in-cylinder charged air amount, the fuel injected into the cylinder, that is, the fuel chamber A by the DI 22 decreases. Therefore, when the air charging efficiency in the cylinder, that is, the combustion chamber A is lower than the normal air charging efficiency in the cylinder and the air-fuel ratio in the cylinder is rich, the fuel injected into the combustion chamber A by the DI 22 is reduced. It is possible to reduce the air-fuel mixture in the vicinity of the spark plug beyond the combustible range by the start-time in-cylinder injection control and the start-time split injection control, and to start the internal combustion engine 1-2. It is possible to suppress deterioration of combustion at the time.

  In the second embodiment, the injection amount correction unit 79 reduces and corrects the set fuel injection amount Q. However, the present invention is not limited to this, and the DI injection is included in the set fuel injection amount Q. Only the amount Q2 may be corrected to decrease. In other words, the injection amount correction unit 79 is set so that only the DI injection amount Q2 is decreased in accordance with the decrease in the in-cylinder charged air amount during the start-time divided injection control by the start-time divided injection control unit 77. Of the Q, only the DI injection amount Q2 may be corrected.

  In the first and second embodiments, when the end condition is satisfied, the processing unit 72 may end the start time division injection control and perform normal control as injection control. The normal control is, for example, injection control that can supply the internal combustion engines 1-1 and 1-2 with a fuel injection amount that can maintain the operation of the internal combustion engines 1-1 and 1-2 that have been started. Here, the end condition is set based on at least one of a physical quantity that can be determined that the start of the internal combustion engines 1-1 and 1-2 has been completed and a physical quantity that can be determined that the start time division injection control cannot be performed. Is. In the first and second embodiments, for example, the engine speed of the internal combustion engine 1-1 or 1-2, which is a physical quantity that can be determined that the start of the internal combustion engine 1-1 or 1-2 has been completed, is used as the end condition. It is assumed that the end condition is satisfied when the detected engine speed Ne is equal to or higher than the second predetermined speed Ne2 (a value higher than the first predetermined speed Ne1). The physical quantity that can be determined that the start of the internal combustion engine 1-1, 1-2 has been completed is not limited to the engine speed, but the number of DI22 fuel injections (the engine speed increases as the number of injections increases, It can be determined that the internal combustion engine 1-1, 1-2 has been started) and the elapsed time from the start of fuel injection by the DI 22 (the number of injections increases with the passage of time, the engine speed increases, and the internal combustion engine increases). 1-1, 1-2 can be determined to have been completed). In this case, if the number of injections is equal to or greater than the second predetermined number of injections (a value higher than the first predetermined number of injections), or the second predetermined time (below the first predetermined time) from the start of fuel injection by DI22 Value)), the end condition is satisfied. Here, the second predetermined rotational speed Ne2, the second predetermined number of injections, and the second predetermined time are set to values at which it can be determined that the start of the internal combustion engines 1-1 and 1-2 is completed. Further, as the end condition, a load factor that is a physical quantity that can be determined that the start time division injection control cannot be performed, that is, in-cylinder charging efficiency, is used, for example, based on the detected engine speed Ne and the detected intake air amount. The termination condition may be satisfied if the estimated load factor is equal to or less than a predetermined value. The physical quantity that can be determined that the start time division injection control cannot be performed is not limited to the load factor, and the fuel injection quantity corresponding to DI22 among the fuel injection quantities Q set by the fuel injection quantity setting unit 74. The DI injection amount Q2 or the fuel injection amount Q set by the fuel injection amount setting unit 74 may be the PFI injection amount Q1 that is the fuel injection amount corresponding to the PFI 21. In this case, the termination condition may be satisfied if the DI injection amount Q2 is less than the minimum injection amount of DI22 or the PFI injection amount Q1 is less than the minimum injection amount of PFI21. Further, the end condition may be satisfied when the plurality of conditions are satisfied.

  In the second embodiment, the injection amount correction unit 79 uses the fuel injection amount corresponding to each PFI 21 among the set fuel injection amounts Q at the time of start-up intake path injection control and start-up split injection control. An increase correction of a certain PFI injection amount Q1 may be performed. Here, the correction amount is set based on the fuel adhering to the intake path 5, that is, the port wet, at the time of the first injection of each PFI 21. Further, the injection amount correction unit 79 sets the correction amount by decreasing from the reference correction amount set at the time of start-up intake path injection control and at the start of start-up divided injection control as time elapses. The injection amount correction unit 79 may start the increase correction when the increase condition is satisfied. Here, it is assumed that the increase condition is satisfied when the number of injections of each PFI 21 is equal to or less than a third predetermined number of injections (for example, 3 times) as the increase condition. As the increasing condition, the water temperature of the cooling water of the internal combustion engine 1-1, 1-2 is used. For example, the water temperature detected by a water temperature sensor (not shown) and output to the ECU 7 is equal to or lower than a predetermined temperature, or fuel by each DI 22 It is assumed that the increase condition is satisfied when the third predetermined time or more has elapsed from the start of fuel injection by each DI 22 using the elapsed time from the start of injection. The increase condition may be satisfied when the plurality of conditions are satisfied.

  Further, in the first and second embodiments, the cylinder filling air amount decrease determining unit 78 determines whether the intake valve timing mechanism 45 is abnormal, so that the cylinder filling is performed when the internal combustion engines 1-1 and 1-2 are started. Although it is determined whether or not the air amount is in a reduced state, the present invention is not limited to this, and any device that can determine whether or not the in-cylinder charged air amount is in a reduced state may be used. .

  For example, the in-cylinder charged air amount decrease determination unit 78 may determine whether or not the in-cylinder charged air amount is in a reduced state based on the position learning state of the intake valve timing mechanism 45. The intake valve timing mechanism 45 performs position learning so that the closing timing of the intake valve 41 is once set as the most retarded angle, for example, periodically at start-up so that no deviation occurs in the closing timing of the intake valve 41. Therefore, when the position is not learned, the closing timing of the intake valve 41 is retarded with respect to the reference closing timing. The in-cylinder charged air amount decrease determination unit 78 may determine that the in-cylinder charged air amount is in a reduced state when the position of the intake valve timing mechanism 45 is not learned.

  Further, for example, the cylinder charge air amount decrease determination unit 78 may determine whether or not the cylinder charge air amount decrease state is based on the learning values of the internal combustion engines 1-1 and 1-2. When so-called battery clear or the like is performed in which the internal combustion engines 1-1 and 1-2 are disconnected from the electrical connection between the ECU 7 and the battery and erase the learning values stored in the ECU 7, the intake valve timing mechanism 45 Since the position learning value is deleted, there is a possibility that the in-cylinder charged air amount is reduced. Accordingly, the cylinder charge air amount decrease determination unit 78 determines whether the intake valve 41 is in the cylinder charge air amount decrease state when the battery is cleared and the learning values of the internal combustion engines 1-1 and 1-2 are deleted. It may be determined that the in-cylinder charged air amount is in a reduced state.

  Further, for example, the in-cylinder charged air amount decrease determination unit 78 may determine whether or not the in-cylinder charged air amount is reduced based on the intake state of the intake passage 5. If deposits or the like adhere to the intake passage 5, there is a possibility that the amount of air filled in the cylinder will decrease even if the internal combustion engines 1-1 and 1-2 are under the same starting conditions. The in-cylinder charged air amount decrease determining unit 78 is in the in-cylinder charged air amount decreasing state because there is a possibility that the in-cylinder charged air amount of the intake valve 41 may be decreased when the intake state of the intake passage 5 deteriorates. You may judge. Here, the deterioration of the intake state of the intake path 5 is estimated from past data such as a history of operating conditions of the internal combustion engines 1-1 and 1-2 stored in the ECU 7, for example. For example, the cylinder charge air amount decrease determination unit 78 performs normal control by feedback control based on the air-fuel ratio detected by the A / F sensor 63 during normal operation after the internal combustion engines 1-1 and 1-2 are started. When the fuel injection amount Q is set to be smaller than the set fuel injection amount Q, it is determined that the intake state of the intake passage 5 has deteriorated, and there is a possibility that the in-cylinder charged air amount of the intake valve 41 will be reduced. It may be determined that the in-cylinder charged air amount is reduced.

  As described above, a fuel injection control apparatus according to the present invention includes a fuel injection valve that injects fuel into an intake passage of an internal combustion engine and a cylinder fuel injection valve that injects fuel into the cylinder of the internal combustion engine. It is useful for a control device, and is particularly suitable for suppressing deterioration of combustion at the start of an internal combustion engine.

1 is a diagram illustrating a configuration example of an internal combustion engine according to a first embodiment. FIG. 3 is a diagram illustrating an operation flow of the fuel injection control apparatus according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of an internal combustion engine according to a second embodiment. It is a figure which shows the operation | movement flow of the fuel-injection control apparatus concerning Embodiment 2. FIG.

Explanation of symbols

1-1, 1-2 Internal combustion engine 2 Fuel supply device 21 Intake path fuel injection valve 22 In-cylinder fuel injection valve 3 Internal combustion engine body 4 Valve device 5 Intake path 6 Exhaust path 7 ECU (fuel injection control device)
74 Fuel injection amount setting unit (fuel injection amount setting means)
75 In-cylinder injection control unit at start 76 Intake path injection control unit at start 77 Division injection control unit at start 78 In-cylinder charged air amount decrease determination unit 79 Injection amount correction unit 8 Accelerator opening sensor

Claims (2)

In a fuel injection control device that performs injection control of the fuel by an intake path fuel injection valve that injects fuel into an intake path of the internal combustion engine and an in-cylinder fuel injection valve that injects fuel into the cylinder of the internal combustion engine,
Fuel injection amount setting means for setting a fuel injection amount per cycle of the internal combustion engine;
With
The in-cylinder charged air amount, which is the amount of air charged in the cylinder at the time of starting the internal combustion engine, is not in the in-cylinder charged air amount decreasing state in which the amount is less than the normal in-cylinder charged air amount at the time of starting the internal combustion engine. Immediately after the start of the internal combustion engine, the in-cylinder injection control is performed to supply the fuel of the set fuel injection amount to the internal combustion engine by injection by the in-cylinder fuel injection valve. After in-cylinder injection control, at the time of starting to supply the set fuel injection amount to the internal combustion engine by injection by the intake path fuel injection valve and injection by the in-cylinder fuel injection valve in the compression stroke of the internal combustion engine Perform split injection control,
When the in-cylinder charged air amount is in a reduced state, immediately after starting the internal combustion engine, at the time of starting to supply the set fuel injection amount of fuel to the internal combustion engine by injection by the intake path fuel injection valve A fuel injection control device performing intake path injection control. An injection amount correcting means for correcting the set fuel injection amount;
The fuel injection amount is corrected to decrease in accordance with a decrease in the in-cylinder charged air amount during the start-time in-cylinder injection control and the start-time split injection control. The fuel injection control apparatus according to 1.

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