JP2011089467A - Control method for internal combustion engine, and internal combustion engine system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure starting quickness and starting certainty of an internal combustion engine. <P>SOLUTION: The control method for an internal combustion engine executes: a first predetermined valve close timing setting step for setting valve close timing of an intake valve to be first predetermined close timing set to be retarded from an intake bottom dead center, when a first operation stop request responding to a first mode of a high starting quickness request is issued; and a valve close timing changing step for changing the valve close timing of the intake valve from the first predetermined value close timing to second predetermined valve close timing to be advanced from the first predetermined valve close timing and to be retarded from the intake bottom dead center, after the first predetermined valve close timing setting step is executed and the valve close timing of the intake valve is set to be the first predetermined valve close timing, and when a second operation stop request responding to a second mode of a lower starting quickness request than that in the first mode is issued. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention belongs to a technical field related to an internal combustion engine control method and an internal combustion engine system having an intake valve that opens and closes a combustion chamber.

  Conventionally, in an internal combustion engine system having an intake valve that opens and closes a combustion chamber, the operation of the internal combustion engine is automatically stopped under a predetermined automatic stop condition, and the internal combustion engine is restarted when a predetermined restart condition is established after the automatic stop. There is known a system provided with automatic stop / restart control means.

  For example, Patent Document 1 is an internal combustion engine system provided with this automatic stop / restart control means, and has a valve timing variable mechanism that makes the closing timing of the intake valve variable. In order to reduce vehicle vibration that occurs during restart, a system is disclosed in which the valve closing timing of the intake valve is retarded by a variable valve timing mechanism during automatic stop of the internal combustion engine.

JP 2007-32388 A

  In order to increase the operating efficiency of the internal combustion engine, it is desirable to increase the expansion ratio. However, when the expansion ratio is increased, the compression ratio is increased accordingly. As a result, the air-fuel mixture in the cylinder is overheated during the compression stroke, and abnormal combustion (pre-ignition) such that the unburned air-fuel mixture self-ignites before a desired timing is likely to occur. For example, when the time from when the operation of the internal combustion engine is stopped to when it is started next is short, the temperature in the cylinder is not sufficiently lowered, and abnormal combustion is particularly likely to occur.

  On the other hand, when the internal combustion engine is started, the internal combustion engine cranking is performed several times before scavenging of the cylinder is performed before fuel injection into the cylinder is started, thereby reducing the temperature in the cylinder. Conceivable. However, when restarting an internal combustion engine mounted on a vehicle after it has been automatically stopped, a quick restart is often required, such as starting from a stop at an intersection for waiting for a signal. The method of performing scavenging in a cylinder by executing ranking several times is not preferable because it takes time.

  Therefore, as shown in Patent Document 1, it is possible to suppress an increase in the temperature in the cylinder by retarding the closing timing of the intake valve during the automatic stop of the internal combustion engine and reducing the effective compression ratio of the engine. Conceivable. However, simply delaying the closing timing of the intake valve delays the closing timing of the intake valve until a stop other than the automatic stop based on the assumption that the valve is restarted in a short period after the stop. . For this reason, the effective compression ratio decreases at the time of start-up from a stop other than automatic stop (for example, during cold start), and as a result, sufficient startability may not be ensured.

  The present invention has been made in consideration of such a problem, and an object thereof is to ensure the start-up speed and the start-up reliability of the internal combustion engine.

  In order to solve the above-mentioned problems, the present invention provides a control method for an internal combustion engine having an intake valve that opens and closes a combustion chamber of a cylinder by reciprocating in synchronization with rotation of a crankshaft. If there is, the operation of the internal combustion engine is stopped. Then, when there is a first start request, cranking of the internal combustion engine is started, and combustion in the combustion chamber is started at a predetermined time after the cranking starts. In the first mode, when there is a second operation stop request, the operation of the internal combustion engine is stopped. After that, when there is a second start request, cranking of the internal combustion engine is started, and the predetermined time after the cranking is started. A second mode in which combustion in the combustion chamber is started at a later timing, and is performed when the first operation stop request is made in the first mode, and the intake valve closing timing is A first predetermined valve closing timing setting step for setting a first predetermined valve closing timing set at a retard angle side with respect to the dead center and the first predetermined valve closing timing setting step are performed to close the intake valve. Is set to the first predetermined valve closing timing, and when the second operation stop request is made, the intake valve closing timing is changed from the first predetermined valve closing timing to the first predetermined valve closing timing. There is provided a control method for an internal combustion engine, comprising: a valve closing timing changing step for changing to the second predetermined valve closing timing on the advance side and on the retard side from the intake bottom dead center.

  In this method, the operation of the internal combustion engine is stopped in the first mode that is executed under the condition that the time from the start request of the internal combustion engine (first start request) to the start of combustion is relatively short and the quick start request is high. When there is a request (first operation stop request), the closing timing of the intake valve is set to a first predetermined closing timing that is retarded from the intake bottom dead center. On the other hand, in the second mode that is executed under the condition that the time from the start request of the internal combustion engine (second start request) to the start of combustion is relatively long and the quick start request is low, the operation stop request of the internal combustion engine When there is a (second operation stop request), the second predetermined valve closing timing of the intake valve is advanced from the first predetermined valve closing timing and retarded from the intake bottom dead center It is time. When the second operation stop request is made after the intake valve closing timing is set to the first predetermined valve closing timing in accordance with the first operation stop request, even if the internal combustion engine is stopped. Then, the closing timing of the intake valve is advanced and changed to the second predetermined closing timing.

  Thus, in the first mode in which the quick start request is high, the closing timing of the intake valve is retarded from the intake bottom dead center when the operation of the internal combustion engine is stopped. The effective compression ratio can be lowered to suppress an abnormal rise in the in-cylinder temperature. For this reason, even if the in-cylinder scavenging by cranking is not performed to reduce the in-cylinder temperature, the occurrence of abnormal combustion such as pre-ignition can be prevented, and the internal combustion engine can be started quickly.

  Even after the intake valve closing timing is set to the first predetermined valve closing timing on the retard side in accordance with the first operation stop request, the operation of the internal combustion engine is stopped in accordance with this operation stop request. Since the closing timing of the intake valve is advanced from the first predetermined closing timing to the second predetermined closing timing in response to the second operation stop request, a quick start request executed after this second operation stop request At the time of start-up under a low condition, it is possible to sufficiently secure an effective compression ratio of the internal combustion engine and improve its start reliability.

  Thus, according to this method, it is possible to ensure start-up speed and improve start-up reliability.

  In the present invention, the internal combustion engine is mounted on a vehicle, and the first operation stop request is automatically made at least when the vehicle is stopped regardless of the operation of the vehicle occupant. It is preferable that the second operation stop request is manually made by an occupant of the vehicle (claim 2).

  According to this, for example, in a vehicle or the like equipped with an idle stop system that stops the operation of the internal combustion engine regardless of the operation of the occupant during idling, the internal combustion engine is When the operation is automatically stopped, the closing timing of the intake valve is set to the first predetermined closing timing on the retard side, and restarting is performed when the closing timing of the intake valve is in the state of the first predetermined closing timing. Since it is performed, the requirement of quick start at the time of restart can be fully satisfied.

  On the other hand, when the second operation stop request is made by the occupant's manual operation (ignition key operation, etc.) and the operation of the internal combustion engine is stopped, the closing timing of the intake valve is set to the second predetermined closing timing on the advance side. Since the start is performed in the state where the intake valve is closed at the second predetermined valve closing timing, it is possible to sufficiently satisfy the start certainty required at the start.

  In the present invention, the internal combustion engine further includes an electric motor capable of changing a closing timing of the intake valve, and the first predetermined closing of the closing timing of the intake valve by the closing timing changing step. The change from the timing to the second predetermined valve closing timing is preferably performed by the electric motor.

  According to this, even after the closing timing of the intake valve is set to the first predetermined closing timing in accordance with the first operation stop request, the operation of the internal combustion engine is stopped in accordance with this operation stop request. By using the electric motor, the intake valve closing timing can be changed from the first predetermined closing timing to the second predetermined closing timing in response to the second operation stop request.

  The present invention further includes a motor temperature determination step for determining whether or not the temperature of the electric motor is equal to or lower than a preset reference temperature. In the valve closing timing changing step, the electric motor is included in the motor temperature determination step. When the temperature of the intake valve is determined to be equal to or lower than the reference temperature, the closing timing of the intake valve is changed from the first predetermined closing timing to the second predetermined closing timing, and the temperature of the electric motor is changed to the reference temperature. When it is determined that the temperature is higher than the temperature, it is preferable to maintain the closing timing of the intake valve at a first predetermined closing timing.

  During the operation stop of the internal combustion engine after setting to the first predetermined valve closing timing accompanying the first operation stop request, hot air is often trapped in the internal combustion engine (periphery), which temporarily increases the temperature of the internal combustion engine (periphery). Increase. The electric motor that changes the closing timing of the intake valve also temporarily rises in temperature due to the temperature rise of the internal combustion engine (periphery). The electric motor has a characteristic that when the temperature rises above a certain temperature (reference temperature), the magnetic force decreases (the generated torque decreases), and the closing timing of the intake valve is changed while the operation of the internal combustion engine is stopped. In this case, there is a possibility that the closing timing of the intake valve cannot be suitably changed due to insufficient torque generated by the electric motor. That is, the amount of change (advance amount) from the first predetermined valve closing timing to the second predetermined valve closing timing is insufficient and the effective compression ratio cannot be sufficiently increased, and the start certainty at the time of the second start request is increased. May decrease.

  On the other hand, according to the above method, the intake valve closing timing is changed only when the motor temperature is equal to or lower than the reference temperature, so the first predetermined valve closing timing of the intake valve closing timing is changed. It can be suppressed that the change amount (advance amount) from the timing to the second predetermined valve closing timing is insufficient and the start reliability at the time of the second start request is lowered.

  The present invention also provides an internal combustion engine having an intake valve that opens and closes a combustion chamber of a cylinder by reciprocating in synchronization with the rotation of the crankshaft, and the closing timing of the intake valve of the internal combustion engine is determined by the rotation of the crankshaft. An intake valve closing timing variable mechanism that is variable with respect to the phase, a fuel supply means that supplies fuel to the combustion chamber, a starter motor that cranks the crankshaft, the intake valve closing timing variable mechanism, and the fuel supply And a control means for controlling the operation of the starter motor, wherein the control means operates the internal combustion engine when there is a first operation stop request for stopping the operation of the internal combustion engine. If the fuel supply means is controlled to stop the fuel supply to the combustion chamber to stop the engine, and then there is a first start request for starting the internal combustion engine, A first mode in which the starter motor is controlled so that the crank motor starts cranking of the crankshaft, and the fuel supply means is controlled to start combustion in the combustion chamber at a predetermined time after the cranking starts. And when there is a second operation stop request for stopping the operation of the internal combustion engine, the fuel supply means is controlled to stop the fuel supply to the combustion chamber in order to stop the operation of the internal combustion engine, and then the internal combustion engine When there is a second start request for starting the engine, the starter motor controls the starter motor to start cranking of the crankshaft, and at a time later than the predetermined time after the cranking starts. A second mode for controlling the fuel supply means to start combustion in the combustion chamber, and the first mode. When the first operation stop request is made in the intake valve, the intake valve closing timing variable mechanism is set so that the closing timing of the intake valve becomes a first predetermined valve closing timing set on the retard side from the intake bottom dead center. And controlling the intake valve closing timing variable mechanism so that the closing timing of the intake valve becomes the first predetermined valve closing timing in response to the first operation stop request, and then the second operation. When there is a stop request, the closing timing of the intake valve is changed from the first predetermined closing timing to the second timing that is advanced from the first predetermined closing timing and retarded from the intake bottom dead center. An internal combustion engine system configured to control the intake valve closing timing variable mechanism so as to change to a predetermined valve closing timing is included (claim 5).

  According to this internal combustion engine system, the control means executes the first under a situation where the time from the start request of the internal combustion engine (first start request) to the start of combustion is relatively short and the quick start request is high. In the mode, when there is an engine operation stop request (first operation stop request), the intake valve closing timing is set to the first predetermined valve closing timing on the retarded side. On the other hand, in the second mode that is executed under the condition that the time from the start request of the internal combustion engine (second start request) to the start of combustion is relatively long and the quick start request is low, the operation stop request of the internal combustion engine When there is a (second operation stop request), the intake valve closing timing is set to the second predetermined valve closing timing on the advance side. Then, when the second operation stop request is made after the intake valve closing timing is set to the first predetermined valve closing timing in response to the first operation stop request, the intake air is taken in even during the operation stop of the internal combustion engine. The valve closing timing is changed (advanced) from the first predetermined valve closing timing to the second predetermined valve closing timing.

  Therefore, in the first mode in which the quick start request is high, when the first operation stop request is made, the intake valve closing timing is set to the first predetermined valve closing timing on the retarded side. The internal combustion engine's effective compression ratio can be lowered to suppress an abnormal rise in the in-cylinder temperature. Abnormal combustion such as pre-ignition can be achieved without reducing the in-cylinder temperature by scavenging the cylinder. Can be prevented, and the internal combustion engine can be started quickly.

  On the other hand, in the second mode in which the quick start request is smaller than the first mode, when the second operation stop request is made, the intake valve closing timing is set to the second predetermined closing timing on the advance side. At the subsequent start, it is possible to sufficiently secure the effective compression ratio of the internal combustion engine and improve the start reliability. In addition, even after the intake valve closing timing is set to the first predetermined closing timing on the retarded side in response to the first operation stop request, the internal combustion engine is stopped in response to the second operation stop request. In spite of the fact that the closing timing of the intake valve is advanced (changed to the second predetermined closing timing), the quick start request executed after this second operation stop request is low. At the time of starting, it is possible to sufficiently secure an effective compression ratio of the internal combustion engine and improve its starting reliability.

  As described above, according to the present invention, it is possible to ensure the start-up speed while avoiding the occurrence of abnormal combustion, and to ensure the start-up reliability.

1 is a block diagram showing an overall configuration of an engine system according to an embodiment of the present invention. It is a cross-sectional view showing an intake camshaft phase varying mechanism. It is a flowchart which shows the engine control method which concerns on 1st Embodiment performed with an engine controller. It is a flowchart which shows the normal start control method performed with an engine controller. It is a flowchart which shows the automatic restart control method performed with an engine controller. It is a flowchart which shows the engine control method which concerns on 2nd Embodiment performed with an engine controller. It is a flowchart which shows the engine control method which concerns on 3rd Embodiment performed with an engine controller. It is the graph which compared the lift curve of the intake valve immediately after engine starting, and the time of normal driving | operation.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows the overall structure of an engine system (internal combustion engine system) 200 according to an embodiment of the present invention. The engine system 200 includes an engine (internal combustion engine) 1 and an engine controller 100 that controls various actuators provided in the engine 1.

  The engine 1 is a four-cycle spark ignition type internal combustion engine mounted on a vehicle such as an automobile, and its output shaft is coupled to drive wheels via a transmission to propel the vehicle. The engine 1 includes a cylinder block 12 and a cylinder head 13 mounted thereon. A plurality of cylinders 11 are formed inside the cylinder block 12 and the cylinder head 13. Although the number of these cylinders 11 is not specifically limited, For example, four cylinders 11 are formed. A crankshaft 14 is rotatably supported on the cylinder block 12 by a journal, a bearing, or the like. In FIG. 1, symbol SW4 is a cooling water temperature sensor that is disposed facing a cooling water jacket provided in the cylinder block 12 and detects the temperature of this cooling water, and the cooling water temperature sensor SW4 detects its detection signal. Is output to the engine controller 100.

  A starter unit 81 that starts the engine 1 by applying a driving force to the crankshaft 14 is provided on a side surface of the cylinder block 12.

  The starter unit 81 includes a starter motor 81a and a pinion gear 81b. The rotation shaft of the pinion gear 81b is coaxial with the output shaft of the starter motor 81a and reciprocates along the rotation shaft. The crankshaft 14 is provided with a flywheel (not shown) and a ring gear 82 fixed to the flywheel coaxially with respect to the center of rotation. When the engine 1 is started using the starter unit 81, the pinion gear 81b moves to a predetermined meshing position and meshes with the ring gear 82, whereby the crankshaft 14 is rotationally driven (cranked). It is like that.

  A piston 15 is slidably fitted in each cylinder 11 formed in the cylinder block 12, and a combustion chamber 17 is formed above each piston 15.

  Here, in this embodiment, the geometric compression ratio of the engine 1 which is a ratio to the volume of the combustion chamber 17 when the piston 15 is located at the top dead center is set to approximately 14. Of course, the value of this geometric compression ratio is not limited to 14. For example, a higher geometric compression ratio is preferable from the viewpoint of improving engine efficiency. However, when the geometric compression ratio is increased, the temperature in the cylinder 11 becomes too high in the compression process, and the possibility of self-ignition occurring at an unexpected timing increases. For this reason, the geometric compression ratio of the engine 1 is preferably 13 or more and 16 or less.

  The cylinder head 13 is provided with a spark plug 52. The tip electrode of the spark plug 52 faces the top of the combustion chamber 17 of each cylinder 11. The spark plug 52 is energized at a predetermined timing by an ignition system 51 that operates in response to a control signal SA from the engine controller 100, and ignites the air-fuel mixture in the cylinder 11.

  The cylinder head 13 is provided with a fuel injection valve 53. The tip of the fuel injection valve 53 faces the peripheral edge of the combustion chamber 17 of each cylinder 11. The fuel injection valve 53 is driven by a fuel supply system 54 that operates in response to a control signal FP from the engine controller 100, and performs a predetermined amount of fuel injection at a predetermined timing.

  The cylinder head 13 is formed with an intake port 18 and an exhaust port 19 communicating with each combustion chamber 17. The cylinder head 13 includes an intake valve (intake valve) 21 for shutting off each intake port 18 from the combustion chamber 17, and an exhaust valve (exhaust valve) 22 for shutting off each exhaust port 19 from the combustion chamber 17. And are provided. The intake valve 21 and the exhaust valve 22 are respectively coupled to the crankshaft 14 via an intake valve drive mechanism 30 and an exhaust valve drive mechanism 40, which will be described later, and the intake port 18 and the exhaust port 19 are connected at a predetermined timing. Open and close. The intake valve 21 and the exhaust valve 22 switch between communication / blocking of the combustion chamber 17 and the intake passage 25 and the exhaust passage 26 by opening and closing the ports 18 and 19. Here, in FIG. 1, symbol SW <b> 3 is an intake air temperature sensor that is disposed facing the intake passage 25 and detects the intake air temperature, and the intake air temperature sensor SW <b> 3 outputs a detection signal to the engine controller 100. .

  The intake valve drive mechanism 30 and the exhaust valve drive mechanism 40 have an intake camshaft 31 and an exhaust camshaft 41, respectively. The intake camshaft 31 and the exhaust camshaft 41 are connected to the crankshaft 14 via a chain transmission mechanism such as a known chain / sprocket mechanism.

  The chain transmission mechanism is configured such that the camshafts 31 and 41 rotate once while the crankshaft 14 rotates twice. Here, symbols SW1 and SW2 are a crank angle sensor and a cam angle sensor, respectively. The crank angle sensor SW1 outputs a pulse signal to the engine controller 100 in response to the passage of convex portions formed at equal intervals on the outer peripheral portion of a rotor (not shown) that is attached to the crankshaft 14 so as to rotate together. . The cam angle sensor SW2 is in response to the passage of a convex portion (provided at a position corresponding to a preset crank angle) formed on the outer peripheral portion of the rotor that is integrally attached to the camshaft 31 (or 41). The pulse signal is output to the engine controller 100. The engine controller 100 determines each cylinder (determines whether each cylinder 11 is in the intake, compression, expansion, or exhaust process) based on the pulse signals from both the sensors SW1 and SW2, and the crank. The rotation angle (crank angle ° CA) of the shaft 14 is calculated.

  The valves 21 and 22 are always urged in a closing direction by a valve return spring (not shown), and valve lifters 23 and 24 are covered on the stem ends of the valves 21 and 22. The camshafts 31 and 41 make their respective cam portions (not shown) contact the valve lifters 23 and 24, thereby reciprocating the valves 21 and 22 in conjunction with the rotational operation of the camshafts 31 and 41, As a result, the ports 18 and 19 are opened and closed.

  The valve lifters 23 and 24 are composed of hydraulic lash adjusters 23 and 24, and use the hydraulic pressure of an oil pump (not shown) driven by the crankshaft 14, and the cam portions of the camshafts 31 and 41. It is comprised so that the clearance gap between may be filled up. As a specific configuration of the lash adjusters 23 and 24, for example, a known structure disclosed in Japanese Patent Laid-Open No. 2003-56316 can be employed. In the present embodiment, as described above, a direct-acting valve layout in which the valves 21 and 22 are directly driven by the camshafts 31 and 41 (directly driven via the lash adjusters 23 and 24) is adopted. However, the present invention is not limited to this, and a so-called rocker arm type valve layout in which the valves 21 and 22 are driven via rocker arms may be adopted.

  The intake valve drive mechanism 30 has an intake camshaft phase variable mechanism (variable valve timing, hereinafter also referred to as VVT) 32 provided between the chain transmission mechanism and the intake camshaft 31, and this intake VVT32 Thus, the lift curve (opening / closing timing) of the intake valve 21 is changed to the advance side and the retard side. In the present embodiment, the exhaust valve drive mechanism 40 does not have a VVT, but a VVT may be provided in the same manner as the intake valve drive mechanism 30.

  The intake VVT 32 varies the opening / closing timing of the intake valve 21 by changing the rotational phase of the intake camshaft 31 with respect to the crankshaft 14. In the present embodiment, the intake VVT 32 generates a rotational force for changing the rotational phase by an electric motor 151 (see FIG. 2).

  More specifically, as shown in FIG. 2, the intake VVT 32 includes the electric motor 151, a rotor 153 that is integrally connected to the output shaft 151a of the electric motor 151 via a connecting shaft 152, and a gear connected to the rotor 153. It has a sprocket body 154 coupled to it and a cam integrated gear 155 that is also gear-coupled to the rotor 153.

  The electric motor 151 is disposed such that its rotational axis coincides with the rotational axis of the intake camshaft 31.

  The cam-integrated gear 155 is made of a disk-like member that is coaxially connected to one end of the intake camshaft 31 and is integrally coupled to the intake camshaft 31 via a knock pin (not shown). A cylindrical recess is formed on the surface of the cam integrated gear 155 opposite to the camshaft 31. A gear portion 155a that meshes with a gear portion 162a of a rotor boss portion 162 described later is formed on the inner peripheral surface of the cylindrical recess.

  The sprocket main body 154 has a cylindrical shape, and has a sprocket gear portion 154a that meshes with a chain (not shown) of the chain transmission mechanism on the outer peripheral surface thereof. The axis of the sprocket body 154 coincides with the rotation axis of the electric motor 151 (the axis of the intake camshaft 31). A gear portion 154 b that meshes with a gear portion 161 a of the rotor main body 161 described later is formed on the inner peripheral surface of the sprocket main body 154.

  The connecting shaft 152 is a stepped shaft that is connected to the motor output shaft 151a so as to be coaxial with the motor output shaft 151a. The connecting shaft 152 includes a large diameter portion 152a and a small diameter portion 152b.

  A spline tooth portion 152 c that meshes with a spline recess 153 c described later of the rotor 153 is formed on the outer peripheral surface of the small diameter portion 152 b of the connecting shaft 152.

  The rotor 153 includes a rotor main body 161 having a gear portion 161a on the outer peripheral surface and a rotor boss portion 162 having a gear portion 162a on the outer peripheral surface. A spline recess 153 c is formed on the inner peripheral surface of the rotor 153. The rotor 153 rotates integrally with the connecting shaft 152 by spline coupling between the spline recess 153c and the spline teeth 152c.

  The axis of the rotor 153 (the axis of the rotor main body 161 and the rotor boss 162) is eccentric by a predetermined distance from the rotation axis of the electric motor 151 (the axis of the output shaft 151a of the electric motor 151). The amount is not shown because it is small). The number of teeth of the gear part 161a of the rotor body 161 is one less than the number of teeth of the gear part 154b of the sprocket body 154. Similarly, the number of teeth of the gear portion 162a of the rotor boss portion 162 is one less than the number of teeth of the gear portion 155a of the cam-integrated gear 155. As a result, the rotor 153 (the rotor main body 161 and the rotor boss portion 162), the sprocket main body 154, and the cam integrated gear 155 constitute an eccentric planetary gear mechanism.

  When the electric motor 151 is rotated in the same direction as the rotation direction of the sprocket body 154 (the direction that coincides with the rotation direction of the crankshaft 14), the cam-integrated gear 155 rotates in the same direction according to the rotation amount, and the intake cam The rotational phase of the shaft 31 advances with respect to the sprocket body 154 (crankshaft 14). On the other hand, when the electric motor 151 is rotated in the direction opposite to the rotation direction of the sprocket body 154, the rotation phase of the intake camshaft 31 is retarded with respect to the crankshaft 14 in accordance with the rotation amount. The electric motor 151 is controlled in response to a control signal from the engine controller 100.

  The engine controller 100 includes a controller based on a well-known microcomputer. The engine controller 100 is a CPU for executing a program, a memory including a RAM and a ROM for storing the program, and inputting and outputting various signals. And an I / O bus. The engine controller 100 is connected to a battery (not shown) via an ignition switch. The ignition switch is in the off state, the ACC state (accessory state), the on state (state where power can be supplied from the battery to the engine controller 100), the start state (starter motor) in conjunction with the operation of the ignition key (engine key) by the occupant. The switch signal corresponding to each state is output to the engine controller 100.

The engine controller 100 transmits the switch signal output from the ignition switch via the I / O bus, the intake air amount AF detected by the air flow meter 71, and the air in the intake manifold 55 detected by the intake pressure sensor 72. Pressure MAP, intake air temperature detected by intake air temperature sensor SW3, engine coolant temperature detected by cooling water temperature sensor SW4, pulse signals output from crank angle sensor SW1 and cam angle sensor SW2, and detected by oxygen concentration sensor 74 It receives various information such as the oxygen concentration EGO of the exhaust gas, the accelerator pedal depression amount α detected by the accelerator opening sensor 75, and the vehicle speed VSP detected by the vehicle speed sensor 76, and is introduced into the cylinder 11. Air quantity, that is, in the cylinder 11 As air charge amount, etc. (intake efficiency) and the ignition timing becomes an appropriate value according to the operating condition, to calculate the command values for various actuators. For example, command values such as the throttle opening TVO, the fuel injection amount FP, the fuel injection timing, the ignition timing SA, the intake valve timing θ _{IVC_D} , the exhaust valve timing, the EGR valve opening EGR _{open, and the} like are calculated. Are output to a throttle actuator 58 that drives the fuel, a fuel supply system 54, an intake VVT 32 (electric motor 151), an EGR valve actuator 64 that drives the EGR valve 63, and the like.

  The engine controller 100 automatically stops the operation of the engine 1 when an engine automatic stop condition (described later) is satisfied, and when an engine restart condition (described later) is satisfied after the engine 1 is automatically stopped. Automatic stop / restart mode for automatically restarting the engine 1 (corresponding to the first mode in steps S6 to S10 described later) and the operation of the engine 1 is stopped in response to an ignition key operation by the occupant. The control including the normal stop / start mode to be started (control processing in steps S1 to S5 described later and corresponding to the second mode) is executed, and the closing timing of the intake valve 21 is changed according to the mode and the like. It is configured to

  The automatic stop / restart mode is a mode in which so-called idling stop control is performed. As will be described later, the operation of the engine 1 is automatically stopped in an idle operation state, and then the engine 1 is operated based on the operation of an accelerator pedal or the like. Is automatically restarted.

  The engine control process according to the first embodiment in the engine controller 100 will be described with reference to the flowchart of FIG.

  In the first step S1, normal start control according to the operation of the ignition key switch by the occupant is executed. Details of this control will be described later.

  In step S2, a necessary control signal is output to the electric motor 151 which is an operation actuator of the intake VVT 32 in accordance with the operating state of the engine 1, whereby the phase of the intake VVT 32 (that is, the intake camshaft 31 with respect to the crankshaft 14). And the valve timing of the intake valve 21 is set to a timing according to the operating state. This control is executed, for example, so that the overlap period in which both the intake valve 21 and the exhaust valve 22 are open has an appropriate length according to the engine load.

  In step S3, based on the switch signal from the ignition switch, it is determined whether the ignition key is operated and the ignition switch is turned off (IG off). If this determination is NO, the process proceeds to step S6. If YES, the process proceeds to step S4.

  In response to the fact that the ignition key is turned off by the passenger operating the ignition key, that is, the normal operation stop request (second operation stop request) of the engine 1 is made, in step S4, the fuel supply system 54 The output of the control signal to is stopped, and fuel injection by the fuel injection valve 53 is stopped. When the fuel injection is stopped, the operation of the engine 1 stops after a while.

  Further, in response to the request for stopping the normal operation of the engine 1, in step S5, a necessary control signal is output to the electric motor 151 which is an operation actuator of the intake VVT 32, so that the intake VVT 32 is set in advance. Control to the stopped phase. Specifically, the phase control of the intake VVT 32 is performed so that the closing timing of the intake valve 21 becomes the second predetermined closing timing that is retarded from the intake bottom dead center. In the present embodiment, the second predetermined valve closing timing is set to ABDC (After Bottom Dead Center) 70 ° C. A (70 ° C. A after intake bottom dead center).

  On the other hand, in step S6 that proceeds when the determination in step S3 is NO, it is determined whether an engine automatic stop condition, which is a determination condition for determining whether to automatically stop the operation of the engine 1, is satisfied. If this determination is NO, the process returns to step S2, while if YES, the process proceeds to step S7 on the assumption that an automatic stop request (first operation stop request) of the engine 1 has been made. In the present embodiment, when it is assumed that the idling operation state of the engine 1 continues for a predetermined time, the brake pedal operation signal (depression state) continues for a predetermined time, and the vehicle speed VSP is equal to or lower than a predetermined value. In addition, it is determined that the engine automatic stop condition is satisfied and an automatic stop request for the engine 1 is made.

  In step S <b> 7, when the engine automatic stop condition is satisfied and an automatic stop request for the engine 1 is made, a necessary control signal is output to the fuel supply system 54 to stop fuel injection by the fuel injection valve 53. When the fuel injection is stopped, the operation of the engine 1 stops after a while.

  Further, when there is a request for automatic stop of the engine 1, in step S8 (first predetermined valve closing timing setting step), based on the intake air temperature information detected by the intake air temperature sensor SW3, the electric actuator that is the operation actuator of the intake air VVT 32 is used. By outputting a necessary control signal to the motor 151, the phase of the intake VVT 32 is controlled.

  Specifically, the phase control of the intake VVT 32 is performed so that the closing timing of the intake valve 21 becomes the first predetermined closing timing set on the retard side with respect to the second predetermined closing timing. Although the first predetermined valve closing timing may be a constant value, in the present embodiment, the first predetermined valve closing timing is changed according to the intake air temperature. The first predetermined valve closing timing is assumed to increase linearly as the intake air temperature increases within the range of ABDC 95 ° C. to ABDC 110 ° C., and as will be described later, the hydraulic lash adjuster 23 immediately after the engine is started. Even if the closing timing of the intake valve 21 is advanced with respect to the set timing due to the lack of the hydraulic pressure, the value is set so as to become a value that is retarded from the second predetermined closing timing.

  In step S9, it is determined whether an engine restart condition, which is a determination condition for determining whether to automatically restart the engine 1, is satisfied. When this determination is YES, it is determined that an automatic restart request (first start request) of the engine 1 has been made, and the process proceeds to step S10. On the other hand, when this determination is NO, the process proceeds to step S12. In this embodiment, when the accelerator pedal is depressed and the engine automatic stop condition is released, it is determined that the engine restart condition is satisfied and an automatic restart request for the engine 1 is made.

  In step S10, engine automatic restart control is executed in which the engine 1 is automatically restarted regardless of the operation of the ignition key by the passenger. Details of this control will be described later.

  In step S12, it is determined whether or not the ignition key is turned off by the passenger operating the ignition key. If this determination is NO, the process returns to step S9. On the other hand, in the case of YES, the process proceeds to step S5, and a necessary control signal is output to the electric motor 151 that is an operating actuator of the intake VVT 32, whereby the intake air that has been set to the first predetermined valve closing timing in step S8. The phase control of the intake VVT 32 is performed so that the valve closing timing of the valve 21 is advanced to reach the second predetermined valve closing timing. This step S12 is also performed when step S8 is performed and the engine 1 is stopped. Step S5 performed after step S12 (after the determination in step S12 is YES) corresponds to the valve closing timing changing step in the claims.

  Next, normal start control (control processing in step S1) included in the normal stop / start mode in the engine controller 100 will be described based on the flowchart of FIG.

  In step S101, based on the switch signal from the ignition switch, it is determined whether or not the ignition switch is in an on state. If this determination is NO, the determination is performed again. If YES, the process proceeds to step S102. move on.

  In step S102, it is determined whether or not the ignition switch is in a start state. When this determination is NO, the determination is performed again, while when it is YES, the process proceeds to step S103.

  In step S103, when the ignition key is operated by an occupant to start the ignition switch and a normal start request (second start request) for the engine 1 is made, a necessary operation signal is output to the starter unit 81. Then, the starter motor 81a is rotationally driven while the pinion gear 81b is engaged with the ring gear 82 to start cranking.

  In step S104, cylinder discrimination is performed to determine whether each cylinder 11 is in the intake, compression, expansion, or exhaust process. As described above, this cylinder discrimination is performed based on the pulse signals from the crank angle sensor SW1 and the cam angle sensor SW2, but in this embodiment, the pulse signal from the cam angle sensor SW2 is applied a predetermined number of times (for example, 2 to 3). Times) when detected. This makes it possible to accurately determine the cylinder from which the influence of noise has been eliminated, and to perform scavenging in each cylinder 11 with sufficient cranking (by rotating the crankshaft 14 once or twice). Can do.

  As described above, the normal start control in the normal start / stop mode is a start control that is performed when the ignition switch is set to the start state in accordance with the operation of the ignition key by the occupant. Is relatively low. Therefore, as described above, a sufficient amount of time from the start of cranking to the start of fuel injection in the next step S105 can be ensured and the scavenging of the cylinder 11 can be reliably performed without giving the passenger a sense of incongruity. And by this scavenging, the temperature in the cylinder 11 can be sufficiently lowered and the occurrence of abnormal combustion can be avoided.

  In step S105, a necessary control signal is output to the fuel supply system 54 to start fuel injection (fuel supply) by the fuel injection valve 53 to the cylinder 11 that has shifted to the compression process cylinder.

  In step S106, a necessary control signal is output to the ignition system 51 in order to execute ignition by the spark plug near the compression top dead center of the cylinder 11. By this ignition, combustion is started in the cylinder 11 of the compression process cylinder.

  Here, when this normal start control is performed, in step S5, the closing timing of the intake valve 21 is set to the second predetermined closing timing on the advance side, and the effective compression ratio of the engine 1 is It is high. Therefore, the combustion in step S106 and the subsequent combustion are surely performed, and the start is surely performed. In particular, even after the closing timing of the intake valve 21 is set to the first predetermined closing timing in step S8, the closing timing is set to the second timing in response to the ignition switch being turned off in step S12. The normal start control is performed in a state where the effective compression ratio is reliably high, and the start is surely performed.

  In step S107, it is determined whether or not the engine speed Ne exceeds the lower limit threshold speed (500 rpm in the present embodiment) (that is, whether or not the engine 1 has been reliably started) is determined. When NO is NO, the determination is performed again. When YES is determined, the present control process is terminated.

  Next, automatic restart control (control processing in step S10) included in the automatic stop / restart mode in the engine controller 100 will be described based on the flowchart of FIG.

  In step S201, when the engine restart condition is satisfied (the determination in step S9 is YES) and an automatic restart request for the engine 1 is made, a necessary operation signal is output to the starter unit 81. The starter motor 81a is rotationally driven while the pinion gear 81b is engaged with the ring gear 82 to start cranking.

  In step S202, it can be said that the fuel is injected into the cylinder 11 in the expansion stroke when the engine 1 is automatically stopped (also referred to as the cylinder in the expansion stroke when the engine restart condition is satisfied; hereinafter referred to as the expansion stroke cylinder when the engine is stopped). Necessary control signals are output to the supply system 54.

  In step S203, a necessary control signal is output to the ignition system 51 in order to ignite the spark plug 52 provided in the combustion chamber 17 of the expansion stroke cylinder 11 when the engine is stopped. By this ignition, combustion is started in the expansion stroke cylinder 11 when the engine is stopped.

  This automatic restart control is performed under a situation where the required start speed is high, such as starting after stopping at an intersection for waiting for a signal. Therefore, in this automatic restart control, the time from the start of cranking in step S201 to the start of combustion in step S203 is longer than the time from the start of cranking in step S103 to the start of combustion in step S106 in the normal stop / start mode. It is set short. In the present embodiment, steps S201 to 203 are performed so that combustion starts immediately after the cranking starts.

  Here, if the time from the start of cranking to the start of combustion is short, in-cylinder scavenging cannot be performed sufficiently and abnormal combustion may occur. However, when the automatic restart control is performed, in step S8, the closing timing of the intake valve 21 is set to the first predetermined closing timing sufficiently on the retard side, and the effective compression of the engine 1 is performed. The ratio is low. Therefore, an excessive increase in the in-cylinder temperature is suppressed without performing in-cylinder scavenging, so that occurrence of abnormal combustion can be avoided.

  In step S204, as in step S107, it is determined whether or not the engine speed Ne exceeds the lower limit threshold speed. When this determination is NO, the determination is performed again, while when it is YES. This control process ends.

  In the engine system configured as described above, when the ignition 1 is turned off by the occupant in the normal start / stop mode (determined as YES in step S3), the engine 1 is stopped. When the fuel supply is stopped, the closing timing of the intake valve 21 is set to a second predetermined closing timing (= ABDC 70 ° C. A) (the process of step S5 is executed). On the other hand, in the automatic stop / restart mode, when the engine automatic stop condition is satisfied (determined as YES in step S6), the engine 1 is stopped (when the fuel supply is stopped). ), The valve closing timing of the intake valve 21 is set to the first predetermined valve closing timing (= ABDC 95 ° C. A to 110 ° C. A) that is retarded from the second predetermined valve closing timing (the process of step S8 is executed). It ’s like that)

  According to this, when the operation of the engine 1 is stopped in the automatic stop / restart mode in which the quick start request is high, the closing timing of the intake valve 21 is controlled to the retarded side (first predetermined closing timing). Therefore, when restarting the engine 1 thereafter, the effective compression ratio can be lowered to suppress an excessive increase in the in-cylinder temperature. Therefore, it is possible to prevent the occurrence of pre-ignition (abnormal combustion) without reducing the in-cylinder temperature by performing in-cylinder scavenging by cranking or the like (without executing the process of step S104 in the normal start / stop mode). Thus, the engine 1 can be started quickly.

  On the other hand, in the normal start / stop mode, when the operation of the engine 1 is stopped, the closing timing of the intake valve 21 is controlled to the advance side (second predetermined closing timing). In this case, a sufficient effective compression ratio can be ensured, and the starting reliability of the engine 1 can be improved. Note that the engine 1 is stopped for a relatively long period of time when the ignition switch is turned off by the occupant's ignition key operation, and then the ignition switch is turned on. It is often carried out in a sufficiently lowered state. Therefore, the occurrence of abnormal combustion is avoided even when the closing timing of the intake valve 21 is set to the advance side as described above. Further, as described above, at the time of this normal start, the cranking time for in-cylinder scavenging can be secured, so that the temperature in the cylinder 11 is lowered by this in-cylinder scavenging, thereby causing abnormal combustion. Can be avoided.

  Normally, in the automatic stop / restart mode, it is assumed that the engine 1 is automatically restarted after the engine 1 is automatically stopped. However, for example, the ignition switch may be turned off without the engine 1 being automatically restarted after the engine 1 is automatically stopped in the idle state. In this case, the next start is a normal start, and the normal start control is performed. On the other hand, in the engine system 1, after the closing timing of the intake valve 21 is set to the first predetermined closing timing in accordance with the automatic stop of the engine 1 in step S8, step S12 is performed. When it is determined that the ignition switch is turned off after the engine 1 is automatically stopped, step S5 is performed to change the closing timing of the intake valve 21 from the first predetermined closing timing to the second predetermined closing timing. ing. Therefore, the normal start control can be reliably performed when the closing timing of the intake valve 21 is the second predetermined valve closing timing, and the start certainty at the normal start can be reliably improved.

  In particular, after the engine 1 stops, the intake valve 21 changes the closing timing of the intake valve 21 from the first predetermined closing timing to the second predetermined closing timing without taking a long time. Since the intake camshaft 31 can be rotated while the viscosity of the lubricating oil after the engine 1 is stopped is relatively low, the intake valve 21 can be easily closed from the first predetermined closing timing to the second predetermined closing timing. In addition, it can be changed reliably.

  Further, the intake VVT 32 is driven by the electric motor 151, and even after the fuel supply is stopped and the operation of the engine 1 is stopped in step S7, the closing timing of the intake valve 21 is changed from the first predetermined closing timing. The second predetermined valve closing timing can be reliably changed.

  Further, in the above-described embodiment, in the automatic restart control, combustion is started from the cylinder 11 in the expansion stroke when the engine restart condition is satisfied (the processes in steps S202 and S203 are executed).

  In this way, the cranking operation by the starter motor 81a at the time of engine restart can be assisted by the combustion pressure in the cylinder 11, thereby further improving the start-up speed of the engine 1 in the automatic stop / restart mode. This can be further improved.

  In the above-described embodiment, the intake valve 21 is connected to the crankshaft 14 via the intake camshaft 31 so as to be interlocked. The stem end of the intake valve 21, that is, the intake valve 21 and the intake camshaft 31. A hydraulic lash adjuster 23 is provided between the two cam portions.

  Thereby, the valve clearance can be appropriately managed according to the operating state of the engine 1 to improve the fuel consumption of the engine 1.

  By the way, when the engine is stopped, the oil in the hydraulic lash adjuster of the cylinder lifted by the valve is released by the urging force of the valve spring, so that the hydraulic lash adjuster 23 does not function. As a result, as shown in FIG. The lift curve 21 sinks downward as a whole, and the closing timing of the intake valve 21 shifts to the advance side as compared with the normal operation state (in the above embodiment, the shift angle D is approximately 20 °). CA). As a result, there is a problem that the effective compression ratio of the engine 1 becomes high and pre-ignition is likely to occur. In particular, in the automatic stop / restart mode, the cylinder at the time of engine start is larger than that in the normal start / stop mode. Since internal scavenging (corresponding to the processing in step S104) is not executed, pre-ignition (abnormal combustion) is more likely to occur.

  On the other hand, in the above embodiment, when the engine 1 is stopped in the automatic stop / restart mode, the closing timing of the intake valve 21 is set between ABDC 95 ° C. and ABDC 110 ° C. (No. Therefore, even if the closing timing of the intake valve is advanced by 20 ° due to insufficient hydraulic pressure, the effective compression ratio is set from the second predetermined closing timing (= ABDC 70 ° C.). Can be kept low, and the occurrence of pre-ignition (abnormal combustion) can be reliably prevented.

  Next, engine control processing according to the second embodiment in the engine controller 100 will be described based on the flowchart of FIG.

  In this process, steps S1 to S12 are performed in the same manner as the engine control process according to the first embodiment. On the other hand, in this process, steps S22 and S24 are provided after step S12.

  In step S22, it is determined whether or not the temperature of the electric motor 151 is lower than a preset reference temperature. In the present embodiment, the engine controller 100 stores a map of the electric motor temperature according to the intake air temperature and the coolant temperature, and the detection signal of the intake air temperature sensor SW3 and the detection signal of the coolant temperature sensor SW4 are stored in the engine controller 100. Based on this, the temperature of the electric motor 151 is estimated. If the determination is YES, that is, if the estimated temperature of the electric motor 151 is equal to or lower than the reference temperature, the process proceeds to step S5, where the intake VVT 32 is operated by the electric motor 151 and the intake valve 21 is closed. The timing is advanced from the first predetermined valve closing timing to the second predetermined valve closing timing. On the other hand, when the temperature of the electric motor 151 is higher than the reference temperature (when the determination is NO), the process proceeds to step S24.

  In step S24, it is determined whether or not the ignition key is operated by the occupant and the ignition switch is turned on, that is, whether or not the engine 1 is normally started. If this determination is NO, the process returns to step S22 again. On the other hand, if this determination is YES, the routine returns to step S1 and normal start control is performed.

  According to this processing, the temperature of the electric motor 151 is lowered to a reference temperature or lower (determined as YES in step S22), and intake is performed by the electric motor 151 only when the magnetic force (generated torque) of the electric motor 151 is sufficiently exerted. Since the VVT 32 is operated, the closing timing of the intake valve 21 can be reliably changed to the second predetermined closing timing. That is, during the automatic stop of the engine 1, the temperature around the internal combustion engine temporarily rises due to the accumulation of hot air in and around the internal combustion engine, and the electric motor 151 also rises temporarily due to this influence. In some cases, the generated torque may decrease due to a decrease in the magnetic force of the electric motor 151. In contrast, in this process, the intake VVT 32 is operated when the temperature of the electric motor 151 is sufficiently lowered and the generated torque of the electric motor 151 is secured, and the intake VVT 32 can be operated appropriately. The effective compression ratio can be sufficiently increased by reliably changing the closing timing of the intake valve 21 to the second predetermined closing timing.

  Further, when the temperature of the electric motor 151 is higher than the reference temperature (determined as NO in step S22), a sufficient time has not elapsed since the engine 1 was stopped, and the in-cylinder temperature of the engine 1 remains high. It is done. Therefore, in this state, when the ignition switch is turned on and a start request is made, if the closing timing of the intake valve 21 is advanced to the second predetermined closing timing, the in-cylinder temperature of the engine 1 is increased. If the engine 1 is started with the engine 1 being high and the effective compression ratio of the engine 1 is high, abnormal combustion may occur. On the other hand, in this process, when the temperature of the electric motor 151 is high, even when the determination in step S12 is YES and the ignition switch is turned off, the closing timing of the intake valve 21 is the first predetermined timing. Since the valve closing timing is maintained, when the ignition switch is turned on while the temperature of the electric motor 151 is high (YES in step S24), the closing timing of the intake valve 21 is the first predetermined closing timing. Since the engine is started at the valve timing and the effective compression ratio of the engine 1 is low, the occurrence of abnormal combustion can be avoided.

  Next, engine control processing according to the third embodiment in the engine controller 100 will be described based on the flowchart of FIG.

  In this process, steps S1 to S12 are performed in the same manner as the engine control process according to the first embodiment. On the other hand, in this process, steps S32 and S34 are provided after step S5.

  In step S32, whether or not a preset reference time has elapsed after the closing timing of the intake valve 21 is set to the second predetermined closing timing as the ignition switch is turned off (step S5). Is determined. If this determination is NO, step S32 is performed again. On the other hand, if this determination is YES, the process proceeds to step S34. That is, after step S5, when the reference time has elapsed, the process proceeds to step S34.

  In step S34, it is determined whether or not the closing timing of the intake valve 21 is the second predetermined closing timing. If this determination is NO, the process returns to step S5, the intake VVT 32 is operated by the electric motor 151, and the closing timing of the intake valve 21 is set to the second predetermined closing timing again. On the other hand, if this determination is YES, this process ends. In the present embodiment, the rotation pulse and rotation direction of the electric motor 151 are detected by a hall sensor built in the electric motor 151, and the phase of the intake camshaft 31, that is, the valve closing of the intake valve 21 is closed based on this detected value. The timing is calculated, and it is determined whether or not the calculated closing timing of the intake valve 21 is the second predetermined closing timing.

  When the ignition switch is turned off, in step S5, the electric motor 151 operates the intake VVT 32 to set the closing timing of the intake valve 21 to the second predetermined closing timing. Here, for example, when the vehicle stops on a slope, the vehicle may move after the brake pedal is released even after the operation of the engine 1 is stopped and the vehicle is stopped at a predetermined position. At this time, if the transmission connected to the wheels and the engine 1 are connected, the engine 1, that is, the crankshaft 14 rotates. At that time, the gear inside the intake VVT 32 connected to the crankshaft 14 via the chain transmission mechanism may rotate, and the valve closing timing of the intake valve 21 may deviate from the second predetermined valve closing timing.

  On the other hand, in this process, after the ignition switch is turned off, the closing timing of the intake valve 21 is set after the predetermined reference time after the closing timing of the intake valve 21 is set to the second predetermined closing timing. It is determined whether or not the timing is at the second predetermined valve closing timing (step S34). If the valve closing timing deviates from the second predetermined valve closing timing, the second predetermined valve closing timing is set again. Therefore, combustion can be started in a state where the closing timing of the intake valve 21 is reliably at the second predetermined closing timing at the next start, and startability can be ensured. In the present embodiment, after the ignition switch is turned off, the closing timing of the intake valve 21 is set to the second predetermined closing timing, and after the predetermined reference time, once in step S34. Although the determination is made (if the determination in step S34 is YES, the intake valve 21 is reset), after the ignition switch is turned off, the next time the ignition switch is turned on During this period, the determination in step S34 may be performed periodically (if the determination in step S34 is YES, the intake valve 21 is reset).

  The configuration of the present invention is not limited to the above embodiment, but includes various other configurations. That is, in the above-described embodiment, the engine controller 100 executes the idling stop control as described above as the automatic stop / restart mode. However, it is not always necessary to execute the idling stop control. The engine operation control including the / stop mode and the first mode in which the time from the start of cranking to the start of fuel supply is shorter than that in the normal start / stop mode may be used.

  In the above embodiment, the engine 1 is a spark ignition engine, but is not limited to this, and may be a diesel engine or the like that does not have the spark plug 52. In this case, combustion is started by performing fuel injection into the cylinder 11 in steps S105 and S202.

  In the above embodiment, the engine 1 is provided with the hydraulic lash adjuster 23 in order to optimize the valve clearance. However, the lash adjuster 23 is not necessarily provided.

  Further, in the above embodiment, the intake VVT 32 is an electric type that employs the electric motor 151 as its operating actuator, but may be a hydraulic type.

  Moreover, although the example which mounts the said engine system in a vehicle was shown in the said embodiment, it is not restricted to this, For example, you may make it mount in a ship and an aircraft.

1 engine (internal combustion engine)
11 cylinders
14 Crankshaft 15 Piston 17 Combustion chamber 21 Intake valve (intake valve)
22 Exhaust valve 30 Intake valve drive mechanism 32 Intake VVT (Intake valve closing timing variable mechanism)
53 Fuel injection valve (fuel supply means)
54 Fuel supply system (fuel supply means)
81a Starter motor 100 Engine controller (control means)
200 engine system (internal combustion engine system)

Claims (5)

A control method for an internal combustion engine having an intake valve that opens and closes a combustion chamber of a cylinder by reciprocating in synchronization with rotation of a crankshaft,
When there is a first operation stop request, the operation of the internal combustion engine is stopped. After that, when there is a first start request, cranking of the internal combustion engine is started, and in the combustion chamber at a predetermined time after the cranking starts. A first mode for starting combustion of
When there is a second operation stop request, the operation of the internal combustion engine is stopped. After that, when there is a second start request, cranking of the internal combustion engine is started, and a time later than the predetermined time after the cranking starts And a second mode for starting combustion in the combustion chamber,
When the first operation stop request is made in the first mode, the first valve closing timing of the intake valve is set to a first predetermined valve closing timing set to the retard side from the intake bottom dead center. A predetermined valve closing timing setting step;
After the first predetermined closing timing setting step is performed and the closing timing of the intake valve is set to the first predetermined closing timing, when the second operation stop request is made, the closing of the intake valve is performed. A valve closing timing changing step for changing the valve timing from the first predetermined valve closing timing to a second predetermined valve closing timing that is advanced from the first predetermined valve closing timing and retarded from the intake bottom dead center; A method for controlling an internal combustion engine having The method for controlling an internal combustion engine according to claim 1,
The internal combustion engine is mounted on a vehicle,
The first operation stop request is automatically made at least when the vehicle is in a stopped state regardless of the operation of the occupant of the vehicle,
The internal combustion engine control method according to claim 1, wherein the second operation stop request is made manually by a passenger of the vehicle. In the control method of the internal combustion engine according to claim 1 or 2,
The internal combustion engine further includes an electric motor capable of changing the closing timing of the intake valve,
The control of the internal combustion engine, wherein the change of the closing timing of the intake valve from the first predetermined closing timing to the second predetermined closing timing in the valve closing timing changing step is performed by the electric motor. Method. In the control method of the internal combustion engine according to claim 3,
A motor temperature determination step of determining whether the temperature of the electric motor is equal to or lower than a preset reference temperature;
In the valve closing timing changing step, when the temperature of the electric motor is determined to be equal to or lower than the reference temperature in the motor temperature determining step, the first predetermined valve closing timing of the intake valve closing timing to the second predetermined valve closing timing. The valve closing timing is changed, and when it is determined that the temperature of the electric motor is higher than the reference temperature, the closing timing of the intake valve is maintained at a first predetermined valve closing timing. A method for controlling an internal combustion engine. An internal combustion engine having an intake valve that opens and closes a combustion chamber of a cylinder by reciprocating in synchronization with the rotation of the crankshaft, and the valve closing timing of the intake valve of the internal combustion engine is variable with respect to the rotation phase of the crankshaft An intake valve closing timing variable mechanism, a fuel supply means for supplying fuel to the combustion chamber, a starter motor for cranking the crankshaft, an intake valve closing timing variable mechanism, the fuel supply means, and the starter motor. An internal combustion engine system comprising control means for controlling operation,
The control means includes
When there is a first operation stop request for stopping the operation of the internal combustion engine, the fuel supply means is controlled to stop the fuel supply to the combustion chamber in order to stop the operation of the internal combustion engine. When there is a first start request for starting, the starter motor controls the starter motor to start cranking of the crankshaft and starts combustion in the combustion chamber at a predetermined time after the cranking starts. A first mode for controlling the fuel supply means to
When there is a second operation stop request for stopping the operation of the internal combustion engine, the fuel supply means is controlled to stop the fuel supply to the combustion chamber in order to stop the operation of the internal combustion engine. When there is a second start request for starting, the starter motor controls the starter motor to start cranking of the crankshaft, and the combustion chamber is at a time later than the predetermined time after the cranking starts. And a second mode for controlling the fuel supply means to start combustion at
When the first operation stop request is made in the first mode, the intake valve closing timing is set so that the closing timing of the intake valve becomes a first predetermined valve closing timing set on the retard side from the intake bottom dead center. Control the timing variable mechanism, and
When the second operation stop request is made after the intake valve closing timing variable mechanism is controlled so that the intake valve closing timing becomes the first predetermined valve closing timing in response to the first operation stop request. The closing timing of the intake valve is changed from the first predetermined closing timing to the second predetermined closing timing which is advanced from the first predetermined closing timing and retarded from the intake bottom dead center. An internal combustion engine system configured to control the intake valve closing timing variable mechanism.

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