JP2018162672A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate a start of an internal combustion engine, and to reduce power consumption.SOLUTION: An internal combustion engine 1 comprises hydraulic drive-type valve timing variable means for changing a first relative rotation phase of a first cam shaft of either an intake cam shaft 6 or an exhaust cam shaft 7, and electric drive-type valve timing variable means for changing a second relative rotation phase of the other second cam shaft. A control device 20 stores, in a backup memory 29, information indicating a determination result of whether or not the first rotation phase is brought into a lock phase by the time at which the internal combustion engine is stopped, and when the first relative rotation phase is not brought into the lock phase, changes the second relative rotation phase up to one phase of either of the most advance phase or the most retardant phase. Also, when the first relative rotation phase is brought into the lock phase before the internal combustion engine is stopped, the control device defines a crank angle on the basis of a first cam signal, and when the first relative rotation phase is not in the lock phase, defines the crank angle on the basis of a second cam signal while maintaining the second relative rotation phase at one phase.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for an internal combustion engine that determines a crank angle when starting a four-cycle internal combustion engine and controls the internal combustion engine based on the determined crank angle.

  One conventionally known control device for an internal combustion engine of this type (hereinafter referred to as “conventional device”) is an intake side variable valve timing mechanism (hereinafter also simply referred to as “intake side VVT”). An electric motor is adopted as a drive source. Based on a signal (cam signal) from the cam position sensor, the conventional apparatus controls the intake side VVT to be pressed against the most retarded position on the mechanism by the force of the electric motor while keeping the cam phase unchanged. Determine the crank angle.

JP 2014-105680 A (see paragraphs 0008 to 0012)

  When starting the internal combustion engine, it is desirable to determine the crank angle early and accurately based on the cam signal. When the internal combustion engine is started, if the cam phase is not changed by pressing the intake side VVT to the most retarded angle position by the electric motor force as in the conventional device, the crank angle can be detected quickly and accurately based on the cam signal. Can be confirmed.

  However, according to this method, when the internal combustion engine is started, the intake side VVT is always pressed to the most retarded position by the power of the electric motor, so that the power consumption increases, resulting in deterioration of fuel consumption. In particular, in a hybrid vehicle, since the internal combustion engine is frequently stopped and started, according to the conventional device, the remaining capacity of the storage battery tends to be small. As a result, extra fuel is consumed to charge the storage battery.

  The present invention has been made to address the above-described problems. That is, one of the objects of the present invention is to provide a control device for an internal combustion engine that can determine the crank angle quickly and accurately with low power consumption when starting the internal combustion engine.

The control device for an internal combustion engine of the present invention (hereinafter also referred to as “the present invention device”)
Crank that is the rotation angle of the crankshaft from the reference crank angle at the time when the piston of any cylinder of the four-cycle internal combustion engine is at compression top dead center or advanced by a predetermined crank angle within the range of 720 ° from that time A control device (20) for an internal combustion engine that determines an angle and controls the internal combustion engine (1) based on the determined crank angle.

The crankshaft (2);
An intake-side camshaft (6) to which a cam for opening and closing an intake valve of the internal combustion engine is attached, and rotation of the crankshaft is transmitted so that the crankshaft rotates once when the crankshaft rotates twice;
An exhaust-side camshaft (7) to which a cam for opening and closing an exhaust valve of the internal combustion engine is attached and the rotation of the crankshaft is transmitted so that the crankshaft rotates once when the crankshaft rotates twice;
The first relative rotation phase of one of the intake camshaft and the exhaust camshaft with respect to the crankshaft is advanced or retarded by hydraulic drive and attached to the first camshaft. Hydraulically driven valve timing variable means (9 or 8) for changing the valve opening and closing timing;
The second relative rotational phase of the other second camshaft of the intake side camshaft and the exhaust side camshaft with respect to the crankshaft is advanced or retarded by an electric motor and attached to the second camshaft. Electrically driven valve timing variable means (8 or 9) for changing the opening and closing timing of the valve;
A plurality of teeth (22) provided at equal intervals on the outer periphery and a missing tooth portion (23) which is a region where the teeth formed on a part of the outer periphery are not provided, and is synchronized with the crankshaft A rotating crank rotor (21);
A plurality of convex portions (first convex portion 32, second convex portion 34, and third convex portion 36) and a plurality of concave portions (first concave portion 33, second concave portion 35, and third concave portion 37) are alternately provided on the outer periphery. The plurality of convex portions are provided over an angle corresponding to a crank angle having a different width (see FIG. 5B), and the plurality of concave portions are provided over an angle corresponding to a crank angle having a different width. (Refer to FIG. 5B), a first cam rotor (31) that rotates synchronously with the first cam shaft,
A plurality of convex portions (first convex portion 32, second convex portion 34, and third convex portion 36) and a plurality of concave portions (first concave portion 33, second concave portion 35, and third concave portion 37) are alternately provided on the outer periphery. (See FIG. 5B), the plurality of convex portions are provided over an angle corresponding to a crank angle having a different width (see FIG. 5B), and the plurality of concave portions have different widths. A second cam rotor (31) provided over an angle corresponding to the crank angle of the second camshaft and rotating in synchronization with the second camshaft;
A crank angle sensor unit (12) that outputs a pulse (see FIG. 6A) that is a crank signal during a period in which the teeth of the crank rotor pass through the crank rotor tooth detection unit;
During the period when the convex portion of the first cam rotor passes through the first cam rotor convex portion detector, a pulse (see FIGS. 6C to 6G) that is a first cam signal is output. A first cam angle sensor (11 or 10);
During the period in which the convex portion of the second cam rotor passes through the second cam rotor convex portion detector, a pulse (see FIGS. 6C to 6G) that is a second cam signal is output. A second cam angle sensor unit (10 or 11).

Furthermore, the hydraulically driven valve timing varying means includes:
A first rotating body (40) rotating synchronously with the crankshaft;
The first rotary body is arranged coaxially, rotates synchronously with the first camshaft, and can change a relative rotational position with respect to the first rotary body in order to change the first relative rotational phase. Two rotating bodies (50);
A hydraulic drive mechanism (25, 43 and 44) for changing the relative rotational position of the second rotary body with respect to the first rotary body by hydraulic drive;
When the first relative rotation phase becomes a predetermined lock phase (MLP), the relative rotation position of the second rotation body with respect to the first rotation body is mechanically fixed to the rotation position serving as the lock phase. A locking mechanism (60) capable of

Furthermore, the electrically driven valve timing variable device is:
When the second relative rotation phase is the most advanced angle phase, the second relative rotation phase is mechanically restricted from changing to the advance angle side, and the second relative rotation phase is the most retarded angle phase. In some cases, a restriction unit is provided that mechanically restricts the second relative rotation phase from changing to the retard side.

  The control device includes a crank angle corresponding to each rising point of the first cam signal when the first relative rotational phase is a predetermined reference phase (intermediate lock phase MLP), and each of the first cam signals. The crank angle corresponding to the falling point is stored in advance (20, FIG. 6 (b) and FIG. 6 (e)), and the second relative rotational phase is a predetermined reference phase (most retarded phase). A crank angle corresponding to each rising point of the second cam signal and a crank angle corresponding to each falling point of the second cam signal in a certain case are stored in advance (20, FIG. 6 (b) and FIG. 6 (f)).

Furthermore, the control device comprises:
A backup memory (29) for holding stored information even when the internal combustion engine is stopped;
Based on the number of inputs of the crank signal from the rise of the first cam signal to the fall following the rise, or from the fall of the first cam signal to the rise following the fall, The first cam rotor convex portion detecting portion that has passed through the first cam rotor convex portion detecting portion is identified, and the first convex portion when the identified convex portion has finished passing through the first cam rotor convex portion detecting portion. Based on the crank angle stored in advance corresponding to the falling edge of the cam signal or the rising edge of the first cam signal at the time when the specified concave portion has passed through the first cam rotor convex portion detector. First confirming means (20 and step 915 in FIGS. 9 and 11) for confirming the angle;
Based on the number of inputs of the crank signal from the rise of the second cam signal to the fall following the rise, or from the fall of the second cam signal to the rise following the fall, A second portion at the time when the convex portion or concave portion of the second cam rotor that has passed through the second cam rotor convex portion detecting portion is specified and the specified convex portion has passed through the second cam rotor convex portion detecting portion. Based on the crank angle stored in advance corresponding to the falling edge of the cam signal or the rising edge of the second cam signal at the time when the specified concave portion has passed through the second cam rotor convex portion detector. Second determining means for determining the corner (20 and step 925 in FIGS. 9 and 11);
A stop processing unit (20, step 800 to step 895 in FIG. 8 and step 1000 to step 1095 in FIG. 10) for executing processing when the internal combustion engine is stopped when the stop request for the internal combustion engine is received;
A start processing unit (20, step 900 to step 995 in FIG. 9 and step 1100 to step 1195 in FIG. 11) that executes processing at the time of starting the internal combustion engine when the start request for the internal combustion engine is received. .

Furthermore, the stop processing unit
The relative rotational position of the second rotating body with respect to the first rotating body is changed using the hydraulic drive mechanism so that the first relative rotational phase becomes the lock phase (see FIGS. 8 and 10). Step 805),
When the first relative rotation phase becomes the lock phase, the lock mechanism is controlled so as to mechanically fix the relative rotation position of the second rotation body with respect to the first rotation body (FIG. 8). And step 815) of FIG.
It is determined whether or not the first relative rotational phase has become the lock phase before the internal combustion engine stops (step 820 in FIG. 8 and step 1010 in FIG. 10), and the determination result is stored in the backup memory. (Steps 825 and 840 in FIGS. 8 and 10),
If the first relative rotational phase does not become the lock phase before the internal combustion engine stops, the power supply to the control device and the electric motor is extended for a predetermined time (T1 or T2) (see FIG. 8). Step 830, Step 845 and Step 850 and Step 830, Step 845 and Step 1015 in FIG. 10),
While the power supply is extended, the electric motor is controlled so that the second relative rotational phase is one of the most advanced angle phase and the most retarded angle phase (see FIG. 8). Step 855 and step 1020 of FIG. 10 are configured.

  Further, during the predetermined time (T1 or T2) during which the power supply is extended, the second relative rotational phase changes from the other phase to the one of the most advanced phase and the most retarded phase. It is set to a value greater than the time it takes.

The start processing unit
When the determination result stored in the backup memory indicates that the first relative rotational phase has become the lock phase before the internal combustion engine stops (step 910 “Yes” in FIGS. 9 and 11). The crank angle is determined using the first determination means (step 915 in FIGS. 9 and 11),
When the determination result stored in the backup memory indicates that the first relative rotational phase is not the lock phase before the internal combustion engine stops (Step 910 “No” in FIGS. 9 and 11). ), If the one phase is the most advanced angle phase, the electric motor is rotated so that the second relative rotation phase changes to the advance angle side (step 1105 in FIG. 11), and the one phase Is the most retarded phase, while rotating the electric motor so that the second relative rotational phase changes to the retarded side (step 920 in FIG. 9), the second determining means is used to The crank angle is determined (step 925 in FIGS. 9 and 11).

  According to the device of the present invention, regardless of whether or not the first relative rotation phase is the lock phase before the internal combustion engine is stopped, the crank angle is set by the first determination means or the second determination means when the internal combustion engine is started. Confirmed. For this reason, since the crank can be determined earlier than the crank angle is determined based on the crank signal, the start of the internal combustion engine can be accelerated.

  Further, when the crank angle is determined by the first determining means, the first relative rotational phase is mechanically fixed to the lock phase, so that the first relative rotational phase can be prevented from shifting, and the crank is determined accurately. Is done. Further, when the crank angle is determined by the second determining means, the second relative rotation phase is maintained at the most advanced angle phase or the most retarded angle phase, so that the second relative rotation phase can be prevented from being shifted accurately. The crank angle is determined.

  Furthermore, when the crank angle is determined by the second determining means, the electric motor is used to maintain the second relative rotational phase at the most advanced angle phase or the most retarded angle phase, so that electric power is consumed. The determination of the crank angle by the second determination unit is performed only when the crank angle cannot be determined by the first determination unit, that is, when the first relative rotation phase is not the lock phase. For this reason, the frequency of determination of the crank angle by the second determination means can be reduced, and as a result, the amount of power consumption as a whole can be reduced and fuel consumption can be prevented from deteriorating.

  In the above description, in order to facilitate understanding of the invention, names and / or symbols used in the embodiment are attached to the configuration of the invention corresponding to the embodiment described later in parentheses. However, each component of the invention is not limited to the embodiment defined by the names and / or symbols.

FIG. 1 is a schematic configuration diagram of an internal combustion engine and a control device for the internal combustion engine according to an embodiment of the present invention. FIG. 2 is a detailed configuration diagram of the exhaust-side valve timing variable device shown in FIG. FIG. 3 is an explanatory diagram of the valve opening period of the exhaust valve and the valve opening period of the intake side valve when the internal combustion engine is stopped. FIG. 4 is an explanatory view of the spool position of the hydraulic control valve shown in FIG. 1 when the internal combustion engine is stopped. FIG. 5 includes (a) and (b), and (a) is a configuration diagram of the crank rotor. FIG. 5B is a configuration diagram of the cam rotor. FIG. 6 is an explanatory diagram of a correspondence relationship between the crank signal and the cam signal and the crank angle. FIG. 7 shows the intake-side relative when the exhaust-side relative rotational phase becomes the intermediate lock phase before the internal combustion engine stops and when the exhaust-side relative rotational phase does not become the intermediate lock phase before the internal combustion engine stops. It is a timing chart of control regarding a rotation phase, an exhaust side relative rotation phase, and the power supply state to ECU. FIG. 8 is a flowchart showing a routine executed by the CPU of the ECU shown in FIG. 1 when the internal combustion engine is stopped. FIG. 9 is a flowchart showing a routine executed by the CPU of the ECU shown in FIG. 1 when the internal combustion engine is started. FIG. 10 is a flowchart showing a routine executed by the CPU of the ECU according to the modification of the embodiment of the present invention when the internal combustion engine is stopped. FIG. 11 is a flowchart showing a routine executed by the CPU of the ECU according to the modification of the embodiment of the present invention when the internal combustion engine is started.

  Hereinafter, a control device for an internal combustion engine according to an embodiment of the present invention (hereinafter also simply referred to as “control device”) will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a control device and an internal combustion engine to which the control device according to the present embodiment is applied.

  The internal combustion engine 1 is a 4-stroke (cycle) spark ignition internal combustion engine and includes four cylinders (not shown). As shown in FIG. 1, the internal combustion engine 1 includes a crankshaft 2, a timing chain 3, sprockets 4 and 5, an intake side camshaft 6, an exhaust side camshaft 7, an intake side valve timing variable device 8, and an exhaust side valve timing. A variable device 9, an intake side cam angle sensor 10, an exhaust side cam angle sensor 11, and a crank angle sensor 12 are provided.

  The internal combustion engine 1 is controlled by the engine ECU 20. Note that ECU is an abbreviation for electric control unit. The ECU is an electronic control circuit having a microcomputer including a CPU 26, a ROM 27, a RAM 28, a backup memory 29, an interface and the like as main components. The CPU 26 implements various functions to be described later by executing instructions (routines) stored in the memory (ROM 27). The backup memory 29 is a storage device that can hold stored information by being supplied with power by a battery (not shown) even after the internal combustion engine 1 is stopped.

  Further, the ECU 20 is connected to the intake side cam angle sensor 10, the exhaust side cam angle sensor 11, the crank angle sensor 12, and the actuator 25 a of the hydraulic control valve 25.

  In each cylinder of the internal combustion engine 1, a combustion chamber is formed between a crown surface of a piston (not shown) and a cylinder (not shown). An ignition device is disposed at the upper center of the combustion chamber. An intake port (not shown) and an exhaust port (not shown) are disposed on the cylinder head so as to face each other with the ignition device interposed therebetween. When an intake valve (not shown) is opened by a cam that rotates along with the rotation of the intake side camshaft 6 described later, outside air flows into the combustion chamber from the intake port. Similarly, when an exhaust valve (not shown) is opened by a cam that rotates in accordance with the rotation of the exhaust side cam shaft 7 described later, the gas in the combustion chamber is discharged from the exhaust port. Further, a fuel injection valve for directly injecting fuel into the combustion chamber is disposed near the intake port of the cylinder head. For this reason, the ignition device and the fuel injection valve are arranged above the top dead center of the piston of the cylinder head.

  It is desirable that the fuel injection valve is opened at a predetermined timing while the piston moves from the intake top dead center to the intake bottom dead center, and mist fuel is injected into the combustion chamber. The fuel injection timing is desirably an appropriate timing at which the piston is not located near the intake top dead center and the piston is not located near the intake bottom dead center. When fuel is injected when the piston is located near the intake top dead center, there is a problem that the fuel adheres to the piston crown, and when the piston is located near the intake bottom dead center, the fuel is injected. Then, there is a problem that the fuel is not sufficiently atomized. Further, it is desirable that the ignition plug is activated when the piston reaches the vicinity of the compression top dead center, and combustion of the mixed gas of the atomized fuel compressed in the combustion chamber and the outside air is started.

  The crankshaft 2 is connected to the piston of each cylinder via a connecting rod (not shown). The crankshaft 2 rotates by converting the reciprocating motion of the piston into a rotational motion by the connecting rod. The rotation of the crankshaft 2 is transmitted by the timing chain 3 to the intake side camshaft 6 via the sprocket 4 and to the exhaust side camshaft 7 via the sprocket 5. The rotation of the crankshaft 2 is transmitted to the intake-side camshaft 6 and the exhaust-side camshaft 7 so that when the crankshaft 2 rotates twice, the intake-side camshaft 6 and the exhaust-side camshaft 7 rotate once. That is, the intake side camshaft 6 and the exhaust side camshaft 7 rotate at a half speed of the crankshaft 2.

  Eight cams (two cams for each cylinder) (not shown) are provided at predetermined positions corresponding to the respective cylinders of the intake side camshaft 6. As the intake cam shaft 6 rotates, the cam rotates to open and close an intake valve (not shown) provided in the cylinder. Further, eight cams (not shown) (two cams for each cylinder) are provided at predetermined positions corresponding to the respective cylinders of the exhaust side camshaft 7. As the exhaust camshaft 7 rotates, the cam rotates to open and close an exhaust valve (not shown) provided in the cylinder.

  The intake side camshaft 6 is provided with an intake motor side variable valve timing device 8 driven by an electric motor. The intake side valve timing varying device 8 transmits the rotation of the crankshaft 2 transmitted to the sprocket 4 to the intake side camshaft 6 by advancing or delaying the rotation of the crankshaft 2 by an electric motor (not shown). As a result, the relative rotation phase of the intake camshaft 6 with respect to the crankshaft 2 is advanced or retarded, and the opening / closing timing of the intake valve changes. The relative rotational phase of the intake side camshaft 6 with respect to the crankshaft 2 is also simply referred to as “intake side relative rotational phase” for convenience. Such an electric motor drive type valve timing variable device itself is well known (for example, refer to Japanese Unexamined Patent Application Publication No. 2014-105680).

  The electric motor drive type intake side valve timing varying device 8 changes the relative position of the “output shaft (not shown) that rotates synchronously with the intake side camshaft 6” relative to the sprocket 4 by the electric motor, thereby changing the intake side relative rotational phase. Change. The range in which the intake-side relative rotation phase can be changed is limited to a predetermined angle range. In this predetermined angle range, the most advanced phase is referred to as the “most advanced angle phase”, and the most retarded phase is referred to as the “most retarded phase”. When the output shaft is positioned at the most advanced angle position corresponding to the most advanced angle phase with respect to the sprocket 4, the movement of the output shaft toward the advanced angle side with respect to the sprocket 4 is mechanically restricted. Similarly, when the output shaft is positioned at the most retarded angle position corresponding to the most retarded angle phase with respect to the sprocket 4, the movement of the output shaft to the retard angle side with respect to the sprocket 4 is mechanically restricted.

  The exhaust side camshaft 7 is provided with a hydraulically driven exhaust side valve timing varying device 9. The exhaust side valve timing variable device 9 changes the exhaust valve opening / closing timing by advancing or retarding the relative rotational phase of the exhaust side camshaft 7 with respect to the crankshaft 2 by hydraulic drive. The relative rotational phase of the exhaust side camshaft 7 with respect to the crankshaft 2 is also simply referred to as “exhaust side relative rotational phase” for convenience.

  As shown in FIG. 2, the exhaust side valve timing varying device 9 includes a housing rotor 40 and a vane rotor 50. The housing rotor 40 rotates in synchronization with the rotation of the crankshaft 2. The vane rotor 50 rotates in synchronization with the exhaust side camshaft 7. The housing rotor 40 is also referred to as a “first rotating body” for convenience, and the vane rotor 50 is also referred to as a “second rotating body” for convenience.

  The sprocket 5 is pivotally supported by the exhaust side camshaft 7 so as to be rotatable. A housing rotor 40 is fixed to the sprocket 5 with a bolt or the like (not shown). When the rotation of the crankshaft 2 is transmitted to the sprocket 5 by the timing chain 3, the sprocket 5 rotates in synchronization with the crankshaft 2. When the sprocket 5 rotates, the housing rotor 40 also rotates because the housing rotor 40 is fixed to the sprocket 5. For this reason, the housing rotor 40 rotates in synchronization with the crankshaft 2.

  The housing rotor 40 has a cylindrical shape and accommodates the vane rotor 50 therein. The vane rotor 50 is pivotally supported by the exhaust side camshaft 7 so as not to rotate. That is, since the housing rotor 40 and the vane rotor 50 are pivotally supported by the same exhaust side camshaft 7, the housing rotor 40 and the vane rotor 50 are located on the same axis. The rotation of the housing rotor 40 that rotates synchronously with the crankshaft 2 is transmitted to the vane rotor 50, and when the vane rotor 50 rotates, the exhaust side camshaft 7 that is pivotally supported by the vane rotor 50 so as not to rotate is also rotated.

  The vane rotor 50 changes its position relative to the housing rotor 40 by rotating relative to the housing rotor 40 clockwise or counterclockwise as shown in FIG.

  When the relative position of the vane rotor 50 to the housing rotor 40 rotates clockwise from the position shown in FIG. 2 (advanced side shown in FIG. 2), the rotational phase of the vane rotor 50 advances from the rotational phase of the housing rotor 40. . In other words, the rotational phase of the exhaust camshaft 7 advances from the rotational phase of the crankshaft 2. As a result, the relative rotational phase of the exhaust camshaft 7 with respect to the crankshaft 2 advances, and the opening / closing timing of the exhaust valve advances.

  On the other hand, when the relative position of the vane rotor 50 with respect to the housing rotor 40 rotates counterclockwise from the position shown in FIG. 2 (the retarded angle side shown in FIG. 2), the rotational phase of the vane rotor 50 changes to that of the housing rotor 40. Delayed from rotational phase. In other words, the rotational phase of the exhaust camshaft 7 is delayed from the rotational phase of the crankshaft 2. As a result, the relative rotation phase of the exhaust camshaft 7 with respect to the crankshaft 2 is delayed, and the opening / closing timing of the exhaust valve is retarded.

  Further, the vane rotor 50 includes a boss 51 fixed to the exhaust-side camshaft 7 and a plurality (three in this embodiment) of vanes 52 that protrude radially outward from the boss 51.

  The housing rotor 40 is provided with a plurality (three in the present embodiment) of partition walls 41 that protrude radially inward. A storage chamber 42 is formed between the partition walls 41 adjacent to each other in the circumferential direction. The storage chamber 42 is divided into two hydraulic chambers by a vane 52 of a vane rotor 50 disposed therein. The hydraulic chamber behind the vane 52 in the storage chamber 42 in the rotational direction of the exhaust camshaft 7 is an advance chamber 43 as an advance hydraulic chamber. The hydraulic chamber in the accommodation chamber 42 on the front side in the rotational direction of the exhaust camshaft 7 with respect to the vane 52 is a retard chamber 44 as a retard chamber.

  In the exhaust side valve timing variable device 9, when the hydraulic oil is supplied to the retard chamber 44 and the hydraulic oil is discharged from the advance chamber 43, the hydraulic pressure in the retard chamber 44 is activated by the advance chamber 43. It becomes higher than the hydraulic pressure. As a result, the vane rotor 50 rotates relative to the housing rotor 40 in the direction opposite to the rotation direction of the exhaust camshaft 7 (counterclockwise in FIG. 2), and the relative position of the vane rotor 50 with respect to the housing rotor 40 is increased. It changes to the retard side. As a result, the exhaust side relative rotation phase of the exhaust side camshaft 7 with respect to the crankshaft 2 is delayed, and the valve timing of an exhaust valve (not shown) is retarded.

  On the other hand, when hydraulic fluid is supplied to the advance chamber 43 and hydraulic oil is discharged from the retard chamber 44, the hydraulic pressure in the advance chamber 43 becomes higher than the hydraulic pressure in the retard chamber 44. As a result, the vane rotor 50 rotates relative to the housing rotor 40 in the cam shaft rotation direction (clockwise in FIG. 2), and the relative position of the vane rotor 50 to the housing rotor 40 changes to the advance side. As a result, the exhaust side relative rotation phase advances, and the valve timing of an exhaust valve (not shown) is advanced.

  As shown in FIG. 2, the exhaust side valve timing varying device 9 further includes an intermediate lock mechanism 60. In the intermediate lock mechanism 60, the relative position of the vane rotor 50 with respect to the housing rotor 40 is set such that the exhaust-side relative rotational phase is a predetermined intermediate lock phase MLP (see FIGS. 3B and 3C). Fix in place mechanically. As a result, the exhaust-side relative rotation phase is fixed to the intermediate lock phase MLP. The intermediate lock phase MLP is set between the most retarded phase and the advanced most angle phase. The most retarded phase is a phase when the valve timing of an exhaust valve (not shown) is most retarded, and the most advanced phase is the most advanced of the valve timing of an exhaust valve (not shown). Is the phase. In a state where the exhaust side relative rotation phase is fixed to the intermediate lock phase MLP, the valve timing of an exhaust valve (not shown) is fixed to an intermediate time between the most retarded angle timing and the most advanced angle timing. In the present embodiment, the intermediate lock phase MLP is set to a phase suitable for starting the internal combustion engine 1.

  The intermediate lock mechanism 60 includes a lock pin (not shown) provided in the vane rotor 50 and a lock hole (not shown) provided in the housing rotor 40. The lock pin is provided so as to protrude from the vane rotor 50 toward the lock hole. The lock hole is provided at a position where the relative position of the vane rotor 50 with respect to the housing rotor 40 is such that the exhaust-side relative rotational phase becomes the intermediate lock phase MLP (hereinafter referred to as “intermediate lock phase position”). . When the lock pin is fitted into the lock hole, the relative position of the vane rotor 50 to the housing rotor 40 is mechanically fixed to the intermediate lock phase position, and the exhaust side relative rotational phase is fixed to the intermediate lock phase MLP. . The housing rotor 40 may be provided with a lock pin, and the vane rotor 50 may be provided with a lock hole.

  When the spool position of the hydraulic control valve 25 described later is in the lock mode position, the state of the lock pin transitions to a state (operating state) that can project in the lock hole direction. Furthermore, when the spool position of the hydraulic control valve 25 to be described later is a position other than the lock mode, the state of the lock pin transitions to a state where it does not protrude in the lock hole direction (inoperative state).

  When the lock pin is in the activated state, the lock pin is fitted into the lock hole when the exhaust side relative rotation phase becomes the intermediate lock phase MLP. As a result, the relative position of the vane rotor 50 with respect to the housing rotor 40 is mechanically fixed at the intermediate lock phase position. On the other hand, when the lock pin is in an inoperative state, the lock pin does not fit into the lock hole even if the exhaust side relative rotation phase becomes the intermediate lock phase MLP.

  Referring to FIG. 1 again, the electromagnetic actuator 25a of the hydraulic control valve 25 is controlled by the ECU 20, thereby changing the position (spool position) of the spool valve of the hydraulic control valve 25. The hydraulic control valve 25 is a phase control hydraulic control valve function for controlling the hydraulic pressure of the advance chamber 43 and the retard chamber 44 of the exhaust side valve timing varying device 9, and a lock control valve for controlling the hydraulic pressure of the intermediate lock mechanism 60. Hydraulic control function.

  As shown in FIG. 4, the hydraulic control valve 25 realizes four modes of a lock mode, an advance angle mode, a holding mode, and a retard angle mode depending on the spool position. The ECU 20 switches the mode of the hydraulic control valve 25 among a lock mode, an advance angle mode, a holding mode, and a retard angle mode by controlling the spool position of the hydraulic control valve 25.

  In the lock mode, as described above, when the lock pin is activated and the exhaust side relative rotation phase becomes the intermediate lock phase MLP, the relative position of the vane rotor 50 to the housing rotor 40 is mechanically changed to the intermediate lock phase position. Fixed to. In modes other than the lock mode, that is, in the advance angle mode, the hold mode, and the retard angle mode, the lock pin is inoperative and the lock pin cannot be fitted into the lock hole. For this reason, the vane rotor 50 is released from being fixed at the intermediate lock phase position.

In the advance angle mode, the hydraulic control valve 25 discharges the hydraulic oil in the retard chamber 44 to reduce the hydraulic pressure in the retard chamber 44, and supplies the hydraulic oil to the advance chamber 43 to supply the advance chamber 43. The exhaust side relative rotational phase is advanced by increasing the hydraulic pressure.
In the holding mode, the hydraulic control valve 25 maintains the exhaust-side relative rotational phase by holding the hydraulic oil in the advance chamber 43 and the retard chamber 44 and maintaining the hydraulic pressure in each chamber.
In the retard mode, the hydraulic control valve 25 discharges the hydraulic oil in the advance chamber 43 to reduce the hydraulic pressure in the advance chamber 43, and supplies the hydraulic oil to the retard chamber 44 to The exhaust side relative rotation phase is retarded by increasing the hydraulic pressure.

Next, the control of the exhaust side valve timing varying device 9 when the internal combustion engine 1 is stopped will be described with reference to FIGS. 3 (a) to 3 (c) and FIG.
FIG. 3A shows an open period of the exhaust valve in the idle state (hereinafter referred to as “ExVVT”) and an open period of the intake valve (hereinafter referred to as “InVVT”). In the idle state, the exhaust-side relative rotation phase is located at the most advanced angle phase, and the intake-side relative rotation phase is located at the most retarded angle phase. In this case, the overlap between ExVVT and InVVT is the smallest.

  As shown in FIGS. 3B and 3C, the intermediate lock phase MLP in the present embodiment is set to a predetermined phase on the retard side with respect to the most advanced angle phase. Further, as shown in FIG. 3C, when the internal combustion engine 1 is started, the exhaust side relative rotation phase is set to the intermediate lock phase MLP, and the intake side relative rotation phase is set to the most retarded angle phase. As a result, ExVVT and InVVT at the start of the internal combustion engine 1 slightly overlap. As a result, it is possible to improve the emission at the start of the internal combustion engine 1.

  When the internal combustion engine 1 is stopped in response to a stop request (hereinafter also referred to as “engine stop request”), the ECU 20 controls the hydraulic control valve 25 via the actuator 25a, so that the exhaust side relative The rotational phase is changed to the intermediate lock phase MLP. When the exhaust-side relative rotation phase becomes the intermediate lock phase MLP, the relative rotation phase is fixed to the intermediate lock phase MLP by the intermediate lock mechanism 60. More specifically, when the exhaust-side relative rotation phase is advanced from the intermediate lock phase MLP, the ECU 20 delays the exhaust-side relative rotation phase to the intermediate lock phase MLP when the engine stop is requested. The spool position of the hydraulic control valve 25 is temporarily moved to the retard mode position. Thereafter, the ECU 20 moves the spool position of the hydraulic control valve 25 from the retard mode position to the lock mode position, thereby fixing the exhaust-side relative rotation phase to the intermediate lock phase MLP by the intermediate lock mechanism 60.

  However, as shown in FIG. 4, the spool valve of the hydraulic control valve 25 passes through the advance angle mode position while being changed from the retard angle mode position to the lock mode position. Therefore, when the exhaust-side relative rotation phase is advanced from the intermediate lock phase MLP when the engine stop request is made, the spool valve of the hydraulic control valve 25 moves from the retard mode position to the lock mode position. By passing the position of the advance mode in between, the exhaust-side relative rotation phase is advanced excessively. As a result, the exhaust-side relative rotation phase is advanced from the intermediate lock phase MLP, and the exhaust-side relative rotation phase may not be fixed to the intermediate lock phase MLP.

  Therefore, the ECU 20 is referred to as a phase delayed from the intermediate lock phase MLP (hereinafter referred to as “stop preparation phase SPP”) in anticipation of the advancement of the spool valve by passing through the advance angle mode position. ) Temporarily controls the exhaust-side relative rotation phase (see FIG. 3B). When the exhaust-side relative rotation phase becomes the stop preparation phase SPP, the ECU 20 moves the spool valve of the hydraulic control valve 25 to the lock mode position. In this case, even if the exhaust side relative rotational phase is advanced by passing the spool valve through the advance angle mode position, the exhaust side relative rotational phase becomes the intermediate lock phase MLP as shown in FIG. For this reason, the exhaust-side relative rotational phase can be mechanically fixed to the intermediate lock phase MLP by the intermediate lock mechanism 60.

  When the exhaust side relative rotation phase is retarded from the intermediate lock phase MLP, the ECU 20 controls the hydraulic control valve to advance the exhaust side relative rotation phase to the intermediate lock phase MLP when the engine stop is requested. The spool position of 25 is temporarily moved to the position of the advance angle mode. Thereafter, the ECU 20 moves the spool position of the hydraulic control valve 25 from the advance mode position to the lock mode position. In this case, since the above-described problem does not occur, it is not necessary to advance the exhaust-side relative rotation phase to a phase that is advanced more than the intermediate lock phase MLP.

  According to this control method, it is necessary to retard the exhaust-side relative rotation phase until the advance angle due to the spool valve passing through the advance angle mode position, so the exhaust-side relative rotation phase becomes the intermediate lock phase MLP. It takes time. For this reason, the internal combustion engine 1 may stop before the exhaust-side relative rotation phase becomes the intermediate lock phase MLP, that is, before the exhaust-side relative rotation phase is fixed at the intermediate lock phase MLP by the intermediate lock mechanism 60. .

Next, the intake side cam angle sensor 10, the exhaust side cam angle sensor 11, and the crank angle sensor 12 will be described in detail.
First, the crank angle sensor 12 will be described.
One end of the crankshaft 2 is provided with a crank rotor 21 that rotates coaxially and synchronously with the crankshaft 2. As shown in FIG. 5 (a), teeth 22 protruding at equal intervals are provided on the outer periphery of the crank rotor 21, and a predetermined number of teeth 22 are missing on a part of the outer periphery. The missing tooth part 23 which is the area | region which was made is provided. More specifically, 34 teeth 22 are provided on the outer periphery of the crank rotor 21 at intervals of 10 ° CA, and a missing tooth portion 23 which is a region where two teeth are missing is formed.

  The crank angle sensor 12 is disposed in the vicinity of the crank rotor 21. The crank angle sensor 12 includes a crank rotor tooth detection unit and a waveform shaping unit. The crank angle sensor 12 is at a high level during the period when the teeth 22 of the crank rotor 21 pass through the vicinity of the crank rotor tooth detection part, and the teeth 22 of the crank rotor 21 pass through the vicinity of the crank rotor tooth detection part. A pulse that is at a low level in a non-period is output from the waveform shaping section. This pulse is called a “crank signal”. In other words, the crank angle sensor 12 outputs a pulse serving as a crank signal to the ECU 20 while each of the teeth 22 of the crank rotor 21 passes through the vicinity of the crank rotor tooth detector. Therefore, the crank angle sensor 12 outputs a crank signal to the ECU 20 every time the crank angle advances by 10 ° CA. The crank angle sensor 12 includes a crank rotor tooth detection unit and a waveform shaping unit, and is also referred to as a “crank angle sensor unit”.

  On the other hand, at one end of the intake side camshaft 6, a cam rotor 31 that rotates synchronously with the intake side camshaft 6 is provided. Similarly, a cam rotor 31 is provided at one end of the exhaust side camshaft 7 and rotates coaxially and synchronously with the exhaust side camshaft 7. As shown in FIG. 5B, on the outer periphery of the cam rotor 31, a plurality of convex portions (first convex portion 32, second convex portion 34 and third convex portion 36) and a plurality of concave portions (first concave portion 33). , A second recess 35 and a third recess 37) are provided. More specifically, convex portions and concave portions are alternately provided on the outer periphery of the cam rotor 31. That is, on the outer periphery of the cam rotor 31, the first convex portion 32, the first concave portion 33, the second convex portion 34, the second concave portion 35, the third convex portion 36, and the third concave portion 37 are provided on the paper surface of FIG. Are provided in this order clockwise.

  The first convex portion 32 is provided so as to protrude in the radial direction from the concave portion over an angle (30 °) corresponding to a crank angle of 60 ° CA. The first concave portion 33 is provided so as to be recessed from the convex portion over an angle (60 °) corresponding to a crank angle of 120 ° CA. The second convex portion 34 is provided so as to protrude in the radial direction from the concave portion over an angle (90 °) corresponding to a crank angle of 180 ° CA. The second concave portion 35 is provided so as to be recessed from the convex portion at an angle (30 °) corresponding to a crank angle of 60 ° CA. The third convex portion 36 is provided so as to protrude in the radial direction from the concave portion over an angle (80 °) corresponding to a crank angle of 160 ° CA. The third concave portion 37 is provided so as to be recessed from the convex portion over an angle (70 °) corresponding to a crank angle of 140 ° CA.

  The intake side cam angle sensor 10 is disposed in the vicinity of the cam rotor 31 provided on the intake side cam shaft 6. The exhaust side cam angle sensor 11 is disposed in the vicinity of the cam rotor 31 provided on the exhaust side cam shaft 7. The intake side cam angle sensor 10 and the exhaust side cam angle sensor 11 are collectively referred to as a “cam angle sensor”.

  The cam angle sensor incorporates a cam rotor convex portion detection unit and a waveform shaping unit. The cam angle sensor is at a high level during a period in which the convex portions of the cam rotor 31 (the first convex portion 32, the second convex portion 34, and the third convex portion 36) pass in the vicinity of the cam rotor convex portion detecting portion. The waveform forming portion is a pulse that is at a low level during the period in which the concave portions (the first concave portion 33, the second concave portion 35, and the third concave portion 37) of the cam rotor 31 pass in the vicinity of the cam rotor convex portion detecting portion. Output from. This pulse is referred to as a “cam signal”. That is, the cam angle sensor becomes a cam signal during a period in which each of the first convex portion 32, the second convex portion 34, and the third convex portion 36 of the cam rotor 31 passes in the vicinity of the cam rotor convex portion detecting portion. The pulse is output to the ECU 20. The cam angle sensor is also referred to as a “cam angle sensor unit” because it includes a cam rotor convex portion detection unit and a waveform shaping unit.

(Determining the crank angle)
Next, the determination process of the crank angle when the internal combustion engine 1 is started by the ECU 20 will be described with reference to FIG. When the internal combustion engine 1 is started, the ECU 20 determines the crank angle (for example, the compression top dead center of any cylinder as a reference) in order to identify the cylinder to be ignited first (the cylinder that first generates combustion). This is the rotation angle of the crankshaft 2 and is also referred to as “absolute crank angle”). When starting the internal combustion engine 1, the ECU 20 determines the crank angle using “first determination means” or “second determination means” described later.

  First, the crank signal and cam signal input to the ECU 20 will be described. As shown in FIG. 6A, the crank angle sensor 12 outputs a crank signal when the teeth 22 of the crank rotor 21 pass through the crank rotor tooth detection unit. In FIG. 6A, the crank signal is indicated by a line because of the size of the drawing. Actually, the crank signal rises at the timing when the teeth 22 of the crank rotor 21 start to pass through the crank rotor tooth detection unit, and falls at the timing when the teeth 22 of the crank rotor 21 finishes passing through the crank rotor tooth detection unit. . Note that the crank angle sensor 12 does not output a crank signal while the missing tooth portion 23 passes through the crank rotor tooth detecting portion.

  As shown in FIGS. 6C to 6G, the cam angle sensor is configured such that any one of the first convex portion 32, the second convex portion 34, and the third convex portion 36 of the cam rotor 31 serves as a cam rotor convex portion detecting portion. When it passes, it outputs a cam signal. More specifically, the cam signal rises at the timing when each convex portion starts to pass through the cam rotor convex portion detecting portion, and falls at the timing when each convex portion finishes passing through the cam rotor convex portion detecting portion. The cam angle sensor does not output a cam signal while each of the first concave portion 33, the second concave portion 35, and the third concave portion 37 of the cam rotor 31 passes through the cam rotor convex portion detector.

  The ROM 27 of the ECU 20 stores information indicating the relationship between the rising and falling of each cam signal by each convex portion and the corresponding crank angle when the relative rotational phase is a predetermined reference phase. . More specifically, in the ROM 27, the cam signal from the intake side cam angle sensor 10 (hereinafter also referred to as the intake side cam signal) has the intake side relative rotational phase “the latest reference phase. The intake side cam signal information indicating the above relationship in the case of “angular phase” is stored, and the cam signal from the exhaust side cam angle sensor 11 (hereinafter sometimes referred to as the exhaust side cam signal) is the exhaust side. Exhaust side cam signal information indicating the above relationship when the relative rotation phase is “intermediate lock phase MLP as a reference phase” is stored.

  Exhaust side cam signal information will be described in detail. As shown in FIGS. 6B and 6E, the rising 32a of the cam signal by the first protrusion 32 is associated with a crank angle of 390 ° CA. The trailing edge 32b of the cam signal by the first convex portion 32 is associated with a crank angle of 450 ° CA. The rise 34a of the cam signal by the second convex portion 34 is associated with a crank angle of 570 ° CA. The trailing edge 34b of the cam signal by the second convex portion 34 is associated with a crank angle of 690 ° CA. The rise 36a of the cam signal by the third convex portion 36 is associated with a crank angle of 30 ° CA. The cam signal falling edge 36b by the third convex portion 36 is associated with a crank angle of 210 ° CA.

  The intake side cam signal information will be described in detail. In the present embodiment, the same cam rotor 31 as the cam rotor 31 attached to the exhaust side cam shaft 7 is attached to the intake side cam shaft 6 at the same angle as the attachment angle to the exhaust side cam shaft 7. . Further, the relative positional relationship between the cam rotor 31 attached to the intake side camshaft 6 and the intake side cam angle sensor 10 indicates that the cam rotor 31 attached to the exhaust side camshaft 7 and the exhaust side cam angle sensor 11 The relative positional relationship is the same. For this reason, the relationship between the rise and fall of the intake side cam signal and the crank angle is the same as that of the exhaust side cam signal. As described above, the intake-side cam signal information is the relationship between each cam signal and the crank angle when the intake-side relative rotation phase is the most retarded phase. Therefore, as can be understood from FIG. 6B and “FIG. 6F showing the exhaust side cam signal obtained when the exhaust side relative rotation phase is the most retarded phase”, the intake side cam signal In the information, the rising 32c of the cam signal by the first convex portion 32 is associated with a crank angle of 420 ° CA. Further, the trailing edge 32d of the cam signal by the first convex portion 32 is associated with a crank angle of 480 ° CA. The rise 34c of the cam signal by the second convex portion 34 is associated with a crank angle of 600 ° CA. The cam signal falling edge 34d by the second convex portion 34 is associated with a crank angle of 0 ° CA. The rise 36c of the cam signal by the third convex portion 36 is associated with a crank angle of 60 ° CA. The trailing edge 36d of the cam signal by the third convex portion 36 is associated with a crank angle of 240 ° CA.

  The convex portions and concave portions of the cam rotor 31 provided on the intake side camshaft 6 and the exhaust side camshaft 7 are the timing when the missing tooth portion 23 of the crank rotor 21 has finished passing the crank rotor tooth detection portion of the crank angle sensor 12 ( Hereinafter, this timing is also referred to as “when passing”), so that the crank angle can be determined by the first passage of the missing tooth portion 23 and the second passage subsequent thereto, It is provided so that the presence or absence of input is different. More specifically, as shown in FIGS. 6 (c) to 6 (g), when the exhaust side relative rotation phase and the intake side relative rotation phase are in any phase, the cam is not detected when the tooth missing portion 23 passes the first time. Assuming that a signal is input (the pulse level is high), the cam signal is not input (the pulse level is low) when the missing tooth portion 23 passes the second time. Similarly, if the cam signal is not input when the missing tooth portion 23 passes the first time, the cam signal is inputted when the missing tooth portion 23 passes the second time. Thus, the ECU 20 can determine the crank angle based on whether or not the cam signal is input at the timing when the missing tooth portion 23 of the crank rotor 21 is detected (that is, when the missing tooth portion 23 passes).

  Based on the number of crank signals input from the rising edge to the falling edge of the cam signal, the ECU 20 determines that the protrusions that have passed through the cam rotor protrusion detection part of the cam angle sensor are the first protrusion 32 and the second protrusion. It is specified which of the protrusion 34 and the third protrusion 36 is the protrusion. That is, if six crank signals are input between the rising edge of the cam signal and the trailing edge that follows this rising edge, the ECU 20 determines that the convex portion that has passed through the cam rotor convex portion detecting portion of the cam angle sensor is the first. One convex portion 32 is specified. If 12 crank signals are input from the rising edge of the cam signal to the falling edge following the rising edge, the ECU 20 determines that the protruding portion that has passed through the cam rotor protruding portion detecting portion of the cam angle sensor is the second protruding portion. The unit 34 is specified. If 18 crank signals are input between the rising edge of the cam signal and the trailing edge following this rising edge, the ECU 20 determines that the convex portion that has passed through the cam rotor convex portion detecting portion of the cam angle sensor is the third convex portion. The unit 36 is specified.

  The ECU 20 determines that the recesses that have passed through the cam angle sensor are the first recesses 33, the second recesses 35, and the third recesses based on the number of crank signals input from the fall of the cam signal to the rise of the next cam signal. Which one of the recesses 37 is specified. In other words, if 12 crank signals are input between the falling edge of the cam signal and the rising edge that follows the falling edge, the ECU 20 determines that the recessed portion that has passed through the cam rotor protruding portion detecting portion of the cam angle sensor is the first. 1 is specified as the recess 33. If six crank signals are input between the falling edge of the cam signal and the rising edge that follows the falling edge, the ECU 20 determines that the recessed portion that has passed through the cam rotor protruding portion detecting portion of the cam angle sensor is the second recessed portion. Specify 35. If 18 crank signals are input between the falling edge of the cam signal and the rising edge following the falling edge, the ECU 20 determines that the recessed portion that has passed through the cam rotor protruding portion detecting portion of the cam angle sensor is the third recessed portion. 37.

(First determination means)
Assume that the exhaust-side relative rotational phase is fixed to the intermediate lock phase MLP by the intermediate lock mechanism 60 of the exhaust-side valve timing variable device 9 from the time when the engine stop is requested until the internal combustion engine 1 is completely stopped. In this case, after the start operation of the internal combustion engine 1 (after cranking is started), the ECU 20 has the crank angle at the time of specifying the convex portion based on the exhaust side cam signal, and the exhaust gas corresponding to the specified convex portion. It can be determined that the crank angle is associated with the trailing edge of the side cam signal. Similarly, the ECU 20 associates the crank angle at the time when the concave portion is specified based on the exhaust cam signal after the start of the starting operation of the internal combustion engine 1 with the rising of the exhaust cam signal corresponding to the specified concave portion. It can be determined that the crank angle.

For example, if the first identified convex portion 32 after the start of the starting operation of the internal combustion engine 1 is the first convex portion 32, the ECU 20 detects the trailing edge 32b of the exhaust-side cam signal and detects the crank angle at that time. Is determined to be “450 ° CA” and the crank counter is set to “15”.
Further, for example, if the recessed portion specified after the start of the starting operation of the internal combustion engine 1 is the first recessed portion 33, the crank angle at that time is “570” when the rising edge 34 a of the exhaust side cam signal is detected. “CA” is confirmed and the crank counter is set to “19”.

  The ECU 20 includes a crank counter in the RAM 28. The crank counter is “0” when the crank angle is 0 ° CA, and increases by “1” every time the crank angle increases by 30 ° CA. In other words, for example, if the crank counter is “1”, the crank angle is 30 ° CA or more and less than 60 ° CA. The crank counter is set to “23” when the crank angle reaches 690 ° CA, and is reset to “0” when the crank angle reaches 720 ° CA (ie, “0 ° CA”).

  For example, the exhaust side cam signal when the exhaust side relative rotation phase is fixed to the intermediate lock phase MLP is as shown in FIG. In this case, it is assumed that the ECU 20 detects the trailing edge 36b of the exhaust side cam signal after the start operation of the internal combustion engine 1 and detects the leading edge 32a of the next exhaust side cam signal. Eighteen crank signals are input from the detection of the trailing edge 36b to the detection of the leading edge 32a. Therefore, the ECU 20 specifies that the third concave portion 37 has passed through the cam rotor convex portion detecting portion of the exhaust side cam angle sensor 11 between the trailing edge 36b and the leading edge 32a. Here, the rising 32a of the cam signal corresponding to the specified third recess 37, that is, the rising 32a of the cam signal by the first protrusion 32 is associated with a crank angle of 390 ° CA. As a result, the ECU 20 determines the crank angle to “390 ° CA” and sets the crank counter to “13”.

  In addition, using the above-described method, the crank is determined based on the cam signal on the camshaft side that is advanced or retarded with respect to the crankshaft 2 by the hydraulically driven valve timing variable device (exhaust side valve timing variable device 9). The means for determining the corner may be referred to as “first determination means”.

  The exhaust side cam signal when the exhaust side relative rotation phase is the most advanced angle phase is shown in FIG. 6D, and the exhaust side cam signal when the exhaust side relative rotation phase is the most retarded phase is shown in FIG. It is shown in f). Due to the assembly tolerance of the exhaust side camshaft 7 and the timing chain 3, variation (for example, about ± 20 ° CA) occurs in the exhaust side relative rotation phase. The exhaust side cam signal obtained by adding the phase of variation (20 ° CA on the advance side) to the most advanced angle phase is shown in FIG. 6C, and the amount of variation (20 ° CA on the retard side) of the most retarded phase is shown. The exhaust-side cam signal obtained by adding the phases of) is shown in FIG.

  By the way, if the exhaust-side relative rotation phase is not fixed to the intermediate lock phase MLP by the intermediate lock mechanism 60 when the internal combustion engine 1 is stopped last time, the exhaust-side relative rotation phase is not changed after the start of the start operation of the internal combustion engine 1 this time. It will fluctuate. As will be described later, the crank angle is determined based on the exhaust cam signal obtained by advancing the variation phase to the most advanced angle phase, and the exhaust cam signal obtained by retarding the variation phase to the most retarded phase. The crank angle determined on the basis of the crank angle may differ from the original crank angle within a range of 100 ° CA at maximum.

Specifically, in the exhaust side cam signal (FIG. 6E) when the exhaust side relative rotational phase is the intermediate lock phase MLP, the crank angle of the second cylinder is BTDC 330 at the trailing edge 36b of the third convex portion 36. is there. BTDC represents a crank angle (° CA) before the intake top dead center with reference to the compression top dead center of each cylinder. On the other hand, when the exhaust-side relative rotation phase is in another phase (FIGS. 6C, 6D, 6F, and 6G), the second time at the time 36b of the third convex portion 36 falls. The crank angle of the cylinder is a crank angle in the range of BTDC 380 to 280 as described below.
FIG. 6 (c) = exhaust side cam signal obtained by advancing the phase of variation in the most advanced angle phase: BTDC 380
FIG. 6 (d) = exhaust side cam signal in the case of the most advanced angle phase: BTDC 360
FIG. 6 (f) = exhaust side cam signal in the case of the most retarded angle phase:: BTDC300
FIG. 6G = exhaust side cam signal obtained by retarding the phase of the variation to the most retarded angle phase: BTDC280

  For example, when the above-described fuel injection valve is opened and fuel is injected into the combustion chamber (injection timing) is BTDC300, and the exhaust-side relative rotation phase is the intermediate lock phase MLP, the "first determination means" Assume that the crank angle has been established. In this case, fuel is injected by BTDC 320 to BTDC 280 even if the variation in the relative rotational phase (± 20 ° CA) is taken into consideration. However, if the crank angle is determined by the “first determining means” when the exhaust-side relative rotation phase is not the intermediate lock phase MLP, fuel may be injected by the BTDC 400 to the BTDC 200.

  Therefore, for example, when fuel is injected at BTDC 400 or a crank angle in the vicinity thereof, the piston is located near the top dead center, and therefore the amount of fuel adhering to the piston crown surface increases. This reduces the fuel to be vaporized and worsens the combustion. On the other hand, for example, when fuel is injected at the BTDC 200 or a crank angle in the vicinity thereof, the piston is located near the bottom dead center, so that it cannot be atomized sufficiently until the fuel is ignited, and the combustion deteriorates. Such deterioration of combustion leads to deterioration of emission and / or startability of the internal combustion engine 1.

  From the above, it is understood that the determination of the crank angle by the “first determination means” is based on the premise that the exhaust side relative rotation phase is fixed to the intermediate lock phase MLP. In other words, when the exhaust-side relative rotational phase is not fixed to the intermediate lock phase MLP by the intermediate lock mechanism 60, if the internal combustion engine 1 is started based on the crank angle determined by the first determination means, the emission deterioration and There is a possibility that startability of the internal combustion engine 1 is deteriorated.

(Second determining means)
If the exhaust side relative rotation phase does not become the intermediate lock phase MLP from the time when the engine stop is requested until the internal combustion engine 1 is completely stopped, as described above, the crank angle cannot be determined by the first determination means. The ECU 20 determines the crank angle based on the intake side cam signal. More specifically, when the ECU 20 determines that the exhaust-side relative rotation phase is not the intermediate lock phase MLP using a method described later, the ECU 20 sets the intake-side relative rotation phase to the most retarded phase after the internal combustion engine 1 is stopped. To change. Then, the ECU 20 uses the electric motor (not shown) of the intake side valve timing varying device 8 after the start operation of the internal combustion engine 1 (after the start of cranking) to change the intake side relative rotational phase to the retard side. A force is applied to the intake camshaft 6. As a result, the intake side relative rotational phase is maintained at the most retarded phase. The ECU 20 specifies the convex portion or the concave portion that has passed through the cam rotor convex portion detecting portion of the intake side cam angle sensor 10 based on the intake side cam signal while maintaining the intake side relative rotational phase at the most retarded angle phase in this way. To do. Further, the ECU 20 determines the crank angle associated with the rising or rising of the intake side cam signal corresponding to the specified convex portion or concave portion as the crank angle at the specific time of the convex portion or concave portion.

  As described above, when an output shaft (not shown) that rotates synchronously with the intake-side camshaft 6 is located at the most retarded angle position with respect to the sprocket 4, movement of the output shaft to the retarded angle side is mechanically restricted. However, the movement of the output shaft toward the advance side is not restricted. For this reason, ECU20 applies force so that the relative position with respect to the sprocket 4 of the said output shaft may change to a retard angle side using an electric motor. This prevents the intake-side relative rotation phase from advancing more than the most retarded angle phase by moving the output shaft to the more advanced angle position than the most retarded position, and the intake-side relative rotation phase is maximized. The retarded phase can be maintained. As a result, the ECU 20 accurately determines the crank angle using the intake side cam signal based on the cam rotor 31 attached to the intake side camshaft 6 that is not mechanically fixed to the intermediate lock phase MLP. be able to.

  If the intake-side relative rotation phase is the most advanced angle phase, the intake-side relative rotation phase is restricted from changing further to the advance-angle side, and if the intake-side relative rotation phase is the most retarded angle phase, The intake side relative rotational phase is restricted from changing further to the retard side. As described above, when determining the crank angle based on the intake side cam signal, the ECU 20 determines the crank angle while maintaining the intake side relative rotation phase at the most retarded angle phase instead of the most advanced angle phase. The reason will be described in detail.

  When the internal combustion engine 1 is started, if the overlap between InVVT and ExVVT becomes too large, the gas after combustion stays in the combustion chamber, reducing the intake efficiency and possibly causing the situation where the internal combustion engine 1 cannot be started. . For this reason, it is desirable to start the internal combustion engine 1 with a small overlap between InVVT and ExVVT.

  Here, when the intake-side relative rotation phase is the most retarded phase and the exhaust-side relative rotation phase is the most advanced angle phase, InVVT and ExVVT are in the state shown in FIG. It becomes small. In FIG. 3A, the intake-side relative rotation phase is the most retarded phase, and therefore can only change to the advance side (counterclockwise in the drawing). When the intake relative rotation phase changes to the advance side, the overlap between InVVT and ExVVT increases.

  If the intake side relative rotation phase is maintained at the most advanced angle phase when the internal combustion engine 1 is started, the overlap between InVVT and ExVVT becomes large, and the internal combustion engine 1 may not be started. For this reason, when the crank angle is determined based on the intake side cam signal when the internal combustion engine 1 is started, the intake side relative rotation phase is maintained at the most retarded angle phase instead of the most advanced angle phase. Thereby, the overlap between InVVT and ExVVT can be reduced, the internal combustion engine 1 can be started reliably, and emission and / or startability can be improved.

As described above, if the exhaust-side relative rotation phase does not become the intermediate lock phase MLP when the internal combustion engine 1 is stopped, the ECU 20 maintains the intake-side relative rotation phase at the most retarded phase when the internal combustion engine 1 is started. However, the crank angle is determined based on the intake cam signal. For example, if the first identified convex portion 32 after the start of the starting operation of the internal combustion engine 1 is the first convex portion 32, the ECU 20 detects the trailing edge 32d of the intake side cam signal, and the crank angle at that time is detected. Is determined to be “480 ° CA”, and the crank counter is set to “16” (see FIGS. 6B and 6F).
Further, for example, if the concave portion specified after the start operation of the internal combustion engine 1 is the first concave portion 33, the ECU 20 detects that the exhaust side cam signal rising 34c is detected and the crank angle at that time is “600. “CA” is determined, and the crank counter is set to “20” (see FIGS. 6B and 6F).

  In addition, based on the cam signal on the camshaft side that is advanced or retarded with respect to the crankshaft 2 by the electric motor drive type valve timing varying device (intake side valve timing varying device 8) using the above-described method. The means for determining the crank angle may be referred to as “second determination means”.

(Third determining means)
The ECU 20 measures the time required for a predetermined number of crank signals to be input, and measures the rotational speed NE of the internal combustion engine 1 based on the time. Further, the ECU 20 measures the time required for the crankshaft 2 to rotate by 30 ° CA required for the missing tooth portion 23 to pass the crank rotor tooth detecting portion of the crank angle sensor 12 (the missing tooth required time Tk). It is estimated based on the rotational speed NE being used. When the ECU 20 determines that the time from when the crank signal is input to when the next crank signal is input is substantially equal to the missing tooth required time Tk, the missing tooth portion 23 of the crank rotor 21 is The passage of the crank rotor teeth of the crank angle sensor 12 is detected. The timing when the missing tooth portion 23 of the crank rotor 21 passes the crank rotor tooth detecting portion of the crank angle sensor 12 is set to the timing when the piston of a predetermined cylinder reaches a predetermined position. Accordingly, when the ECU 20 detects that the toothless portion 23 has passed the crank angle sensor 12, the ECU 20 determines that the current crank angle is one of the two predetermined crank angles (120 ° CA or 480 ° CA). Can be identified.

  The ECU 20 determines whether or not a cam signal is input (whether a high level of a pulse is detected) at a timing when it is detected that the missing tooth portion 23 has passed the crank rotor tooth detection portion of the crank angle sensor 12. judge. As understood from FIG. 6, if the cam signal is input, the ECU 20 determines that the current crank angle is 150 ° CA and sets the crank counter to “5”. On the other hand, as understood from FIG. 6, if no cam signal is input at this timing, the ECU 20 determines that the current crank angle is 510 ° CA and sets the crank counter to “17”. The means for determining the crank angle based on the crank signal of the ECU 20 as described above may be referred to as “third determination means”. As described above, the crank angle can be reliably determined based on whether or not the cam signal is input when passing through the toothless portion 23 regardless of the exhaust side relative rotation phase and the intake relative rotation phase. The third determining means is not used for determining the crank angle at the time of starting the internal combustion engine 1, but the crank angle after the crank angle is determined by the first determining means or the second determining means at the time of starting the internal combustion engine 1. Used to determine

(Overview of operation)
An outline of the operation of the control apparatus will be described with reference to FIG.
First, until the internal combustion engine 1 stops (until the rotational speed of the internal combustion engine 1 becomes substantially “0”), the exhaust-side relative rotational phase becomes the intermediate lock phase MLP, and the first determinating means is set when the internal combustion engine 1 is started. The case where the crank angle is determined will be described.

  At time t1, the ECU 20 receives a request to stop the internal combustion engine 1. Specifically, the stop request signal (SDES) of the internal combustion engine 1 input to the ECU 20 rises at time t1. When the ECU 20 receives a request to stop the internal combustion engine 1, the ECU 20 stops fuel injection and ignition (II) by the spark plug. As a result, the rotational speed (NE) of the internal combustion engine 1 gradually decreases from time t1 and becomes “0” at time t2. In other words, the internal combustion engine 1 stops at time 2.

  Further, when receiving a request to stop the internal combustion engine 1 at time t1, the ECU 20 controls the exhaust-side valve timing varying device 9 so that the exhaust-side relative rotation phase becomes the intermediate lock phase MLP. As a result, in this example, the exhaust-side relative rotational phase is the intermediate lock phase MLP at time t3 before the internal combustion engine 1 stops. When the exhaust-side relative rotation phase becomes the intermediate lock phase MLP, the ECU 20 stores that fact in the backup memory 29. In FIG. 7, it is assumed that the exhaust-side relative rotation phase before the ECU 20 receives a request to stop the internal combustion engine 1 is the most advanced angle phase.

  Further, at time t3 when the exhaust side relative rotation phase becomes the intermediate lock phase MLP before the internal combustion engine 1 stops, the ECU 20 lowers the power supply request signal (SDEP) to itself, and the power supply request signal Is set to OFF. As a result, the power supply state (SEP) to the ECU 20 falls, and the power supply to the electric motor (not shown) of the ECU 20 and the intake side valve timing varying device 8 is stopped.

  Thereafter, when the ECU 20 receives a request for starting the internal combustion engine 1, the backup memory 29 stores that the exhaust side relative rotational phase has become the intermediate lock phase MLP before the internal combustion engine 1 stops. For this reason, the ECU 20 determines the crank angle using the first determining means described above, and performs control (fuel injection and ignition) for starting the internal combustion engine 1 based on the determined crank angle.

  Next, a case where the exhaust side relative rotation phase does not become the intermediate lock phase MLP until the internal combustion engine 1 is stopped will be described.

  As described above, the stop request signal (SDES) for the internal combustion engine 1 rises at time t1, and the ECU 20 receives the stop request for the internal combustion engine 1. At this time, the ECU 20 stops the fuel injection and ignition (II) by the spark plug, so that the rotational speed (NE) of the internal combustion engine 1 gradually decreases, and the internal combustion engine 1 stops at time t2. Further, the ECU 20 starts control of the exhaust side valve timing varying device 9 so that the exhaust side relative rotation phase becomes the intermediate lock phase MLP at time t1. However, in this example, the exhaust side relative rotational phase is not the intermediate lock phase MLP at time t2 when the internal combustion engine 1 stops. Therefore, the ECU 20 stores in the backup memory 29 that the exhaust side relative rotational phase has not become the intermediate lock phase MLP until the internal combustion engine 1 is stopped.

  Since the exhaust-side relative rotation phase does not become the intermediate lock phase MLP, at time t2, the ECU 20 extends the timing for lowering the power supply request signal (SDEP) to itself by a predetermined time T1. For this reason, the power supply request state (SEP) to the electric motor (not shown) of the ECU 20 and the intake side valve timing varying device 8 is in a state where power is continuously supplied until a predetermined time T1 elapses from the time t2, and the predetermined time from the time t2 The power supply is stopped at time t4 when time T1 has elapsed.

  Further, at time t2, the ECU 20 controls an electric motor (not shown) of the intake side valve timing varying device 8 so that the intake side relative rotational phase becomes the most retarded phase. The aforementioned predetermined time T1 is set to a value equal to or longer than the time required for the intake side relative rotation phase to change from the most advanced angle phase to the most retarded angle phase. Therefore, in FIG. 7, since the intake side relative rotation phase at time t2 is a predetermined phase that is retarded from the most advanced angle phase, the intake side relative rotation phase before the predetermined time T1 elapses from time t2. Becomes the most retarded phase. When the intake side relative rotation phase becomes the most retarded angle phase, the movement of the output shaft (not shown) that rotates synchronously with the intake side camshaft 6 to the retard angle side with respect to the sprocket 4 is regulated.

  Thereafter, when the ECU 20 receives a request for starting the internal combustion engine 1, the backup memory 29 stores that the exhaust side relative rotational phase has not become the intermediate lock phase MLP before the internal combustion engine 1 is stopped. In this case, the present control device rotates in synchronization with the intake side camshaft 6 while controlling the intake side relative rotation phase to be changed to the retard side by an electric motor (not shown) of the intake side valve timing varying device 8. While rotating the electric motor so as to press the output shaft (not shown) to the retard side, the crank angle is determined using the second determining means described above. Then, the present control device performs control (fuel injection and ignition) for starting the internal combustion engine 1 based on the determined crank angle.

  When the exhaust-side relative rotation phase has reached the intermediate lock phase MLP by the above processing until the internal combustion engine 1 stops, the present control device determines the crank angle using the first determination means. On the other hand, when the exhaust-side relative rotational phase is not the intermediate lock phase MLP before the internal combustion engine 1 is stopped, the present control device determines the crank angle using the second determination means. Therefore, regardless of whether or not the exhaust side relative rotational phase is the intermediate lock phase MLP before the internal combustion engine 1 is stopped, when the internal combustion engine 1 is started, the crank angle is determined using the cam signal without using the crank signal. Is confirmed. In other words, the present control apparatus determines the crank angle using the first determination means or the second determination means without using the third determination means when starting the internal combustion engine. As a result, the crank angle can be determined early.

  When the crank angle is determined using the first determining means, the exhaust side relative rotational phase is mechanically fixed to the intermediate lock phase MLP by the intermediate lock mechanism 60, so that the exhaust side relative rotational phase is the intermediate lock phase MLP. The crank angle can be accurately determined. Further, when the crank angle is determined using the second determining means, the crank motor is controlled while controlling the electric motor (not shown) of the intake side valve timing varying device 8 so that the intake side relative rotational phase changes to the retard side. Confirm the corner. Therefore, the intake side relative rotation phase does not change from the most retarded angle phase, so that the crank angle can be determined accurately.

  Only when the exhaust-side relative rotational phase does not become the intermediate lock phase MLP before the internal combustion engine 1 stops, the crank angle is determined using the second determination means that requires control of the electric motor (not shown). That is, when the exhaust-side relative rotational phase becomes the intermediate lock phase MLP before the internal combustion engine 1 stops, the crank angle is set using the first determination means that does not consume power without using the second determination means. Determine. As a result, the frequency with which the crank angle is determined using the second determination means can be reduced, and as a result, the amount of power consumption can be reduced as a whole and fuel consumption can be prevented from deteriorating.

(Specific operation)
When the CPU 26 of the ECU 20 receives a stop request for the internal combustion engine 1 in a state where the exhaust-side relative rotational phase is advanced from the intermediate lock phase MLP, the routine shown in the flowchart of FIG. 8 is executed. . The routine shown in FIG. 8 is a process performed when the internal combustion engine 1 is stopped.

  When the CPU 26 receives a request to stop the internal combustion engine 1, the CPU 26 proceeds to step 800, starts the routine shown in FIG. 8, and proceeds to step 805. The stop request of the internal combustion engine 1 is, for example, when a predetermined operation for stopping the internal combustion engine 1 by a driver (an operation for changing an ignition key switch (not shown) from an on position to an off position) is made. Occur. Alternatively, when the internal combustion engine 1 is mounted on a hybrid vehicle, the stop request is generated from the power management ECU of the hybrid vehicle. Further, when the internal combustion engine 1 is mounted on a vehicle having a start and stop function, the stop request is generated when a condition for automatically stopping the internal combustion engine 1 is satisfied.

  In step 805, the CPU 26 moves the spool position of the hydraulic control valve 25 to the retard mode position, and proceeds to step 810. When the spool position of the hydraulic control valve 25 moves to the retard mode position, the exhaust-side relative rotation phase is retarded. In step 810, the CPU 26 determines whether or not the exhaust-side relative rotation phase has become the stop preparation phase SPP.

  Here, a method for measuring the exhaust-side relative rotation phase will be described. The CPU 26 calculates the rotation angle per predetermined time of the crankshaft 2 based on the number of crank signals (pulse number) input per predetermined time. Then, the CPU 26 calculates the current crank angular velocity based on the calculated rotation angle of the crankshaft 2. Further, the CPU 26 determines a predetermined crank angle DCA (for example, FIG. 6) from a predetermined falling DP of the exhaust side cam signal (for example, refer to the falling of the third convex portion 36 in FIGS. 6C to 6G). Measure the predetermined crank angle arrival time T until it reaches 300 ° CA indicated by a broken line in FIG. At this time, the crank angle is accurately obtained.

  Then, the CPU 26 multiplies the predetermined crank angle arrival time T and the crank angular velocity, thereby increasing the crank angle CA that has traveled from the predetermined falling DP until reaching the predetermined crank angle DCA (for example, FIG. 6C). Thru (see CA in (g)). The crank angle CA 'that is advanced from the predetermined falling DP when the exhaust-side relative rotational phase is the most retarded phase until reaching the predetermined crank angle DCA is preset in the CPU 26. The CPU 26 subtracts the preset crank angle CA ′ from the crank angle CA that has advanced from the predetermined falling DP to the predetermined crank angle DCA. Then, the CPU 26 calculates the current exhaust-side relative rotation phase based on the subtracted value. Note that the CPU 26 uses the falling DP of the cam signal as a reference point for calculating the crank angle CA, but may use the rising of the cam signal. Further, the predetermined crank angle DCA may be an appropriately set crank angle, and it is preferable that about two to three crank angles DCA are set per crank angle 720 ° CA. Note that the CPU 26 can measure the intake-side relative rotation phase by applying the above-described method to the intake-side cam signal.

  In step 810, the CPU 26 measures the exhaust-side relative rotation phase by the method described above. If the measured exhaust-side relative rotation phase becomes the stop preparation phase SPP (see FIG. 3B), step 810 is performed. At step 815, the process proceeds to step 815. In step 815, the CPU 26 moves the spool position of the hydraulic control valve 25 to the lock mode position, and proceeds to step 820. Thereby, the state of the lock pin of the intermediate lock mechanism 60 becomes the operating state. As a result, the intermediate lock mechanism 60 is in a state where the exhaust side relative rotation phase can be fixed to the intermediate lock phase MLP.

  In step 820, the CPU 26 determines whether or not the exhaust-side relative rotation phase measured by the method described above has reached the intermediate lock phase MLP.

  When the exhaust-side relative rotation phase becomes the intermediate lock phase MLP, the CPU 26 determines “Yes” in step 820 and proceeds to step 825. In step 825, the CPU 26 determines that “the exhaust side relative rotation phase has reached the intermediate lock phase MLP by the time the internal combustion engine 1 is stopped. Completion information indicating “fixed” is stored in the backup memory 29, and the process proceeds to Step 830.

  In step 830, the CPU 26 stops supplying power to other than the backup memory 29, proceeds to step 895, and once ends this routine.

  On the other hand, if the exhaust-side relative rotation phase does not become the intermediate lock phase MLP, the CPU 26 determines “No” in step 820 and proceeds to step 835. In step 835, CPU 26 determines whether or not the number N of crank signal inputs per predetermined time is equal to or less than threshold value N1th.

  If the number N of crank signal inputs per predetermined time is equal to or less than the threshold value N1th, the CPU 26 determines that it is immediately before the internal combustion engine 1 stops. In this case, the CPU 26 determines “Yes” at step 835 and proceeds to step 840. In step 840, the CPU 26 stores incomplete information in the backup memory 29 indicating that the exhaust-side relative rotation phase has not become the intermediate lock phase MLP before the internal combustion engine 1 is stopped, and proceeds to step 845.

  In the processing after step 845, the CPU 26 extends the stop of power supply to the electric motor (not shown) of the ECU 20 and the intake side valve timing varying device 8 by a predetermined time T1, and performs the intake side relative rotation during the predetermined time T1. A process of changing the phase to the most retarded phase is performed.

  First, in step 845, the CPU 26 adds “1” to the current timer TMR value, sets the value after adding “1” to the new timer TMR value, and proceeds to step 850. In step 850, CPU 26 determines whether or not the value of timer TMR is equal to or smaller than a predetermined threshold value TMR1th corresponding to predetermined time T1.

  If the value of the timer TMR is equal to or smaller than the threshold value TMR1th, the CPU 26 determines “Yes” in step 850 and proceeds to step 855. In step 855, the CPU 26 controls an electric motor (not shown) of the intake side valve timing varying device 8 so that the intake side relative rotation phase changes to the retard side, and returns to step 845. As described above, the CPU 26 continues to control the electric motor so that the intake side relative rotational phase is changed to the retard side until the value of the timer TMR becomes larger than the threshold value TMR1th corresponding to the predetermined time T1. The predetermined time T1 is set to be longer than the time required for the intake side relative rotation phase to change from the most advanced angle phase to the most retarded angle phase. Therefore, the intake side relative rotation phase can be reliably changed to the most retarded phase.

  On the other hand, when the value of the timer TMR is greater than the threshold value TMR1th, the predetermined time T1 is less than the threshold value N1th after the number N of crank signal inputs per predetermined time (that is, from when the internal combustion engine 1 is considered to have stopped). It has passed. In this case, the CPU 26 makes a “No” determination at step 850 to proceed to step 860. In step 860, CPU 26 initializes the value of timer TMR (that is, sets the value of timer TMR to “0”), and proceeds to step 830. In step 830, the CPU 26 stops supplying power to other than the backup memory 29, proceeds to step 895, and once ends this routine.

  On the other hand, if the exhaust-side relative rotational phase is not the intermediate lock phase MLP, if the number N of crank signals input per predetermined time is greater than the threshold value N1th, the CPU 26 determines that the internal combustion engine 1 has not yet stopped. In this case, the CPU 26 makes a “No” determination at step 835 to return to step 820. In step 820, the CPU 26 determines again whether or not the exhaust-side relative rotation phase has reached the intermediate lock phase MLP.

  Further, if the exhaust relative rotation phase is not the stop preparation phase SPP when the CPU 26 executes the process of step 810, the CPU 26 determines “No” in step 810 and proceeds to step 865. In step 865, CPU 26 determines whether or not the number N of crank signals input per predetermined time is equal to or less than threshold value N1th.

  If the number N of crank signal inputs per predetermined time is equal to or less than the threshold value N1th, the CPU 26 determines that it is immediately before the internal combustion engine 1 stops. In this case, the CPU 26 makes a “Yes” determination at step 865 to proceed to processing subsequent to step 840.

  On the other hand, if the number N of crank signal inputs per predetermined time is greater than the threshold value N1th, the CPU 26 determines that the internal combustion engine 1 has not yet stopped. In this case, the CPU 26 makes a “No” determination at step 865 to return to step 810. In step 810, the CPU 26 determines again whether or not the exhaust side relative rotation phase has reached the stop preparation phase SPP.

  In the above-described example, the stop process when the CPU 26 receives a request for stopping the internal combustion engine 1 in a state where the exhaust-side relative rotation phase is advanced from the intermediate lock phase MLP has been described. In the stop process when the CPU 26 receives a request to stop the internal combustion engine 1 in a state where the exhaust side relative rotation phase is retarded from the intermediate lock phase MLP, the CPU 26 determines in step 805 the spool position of the hydraulic control valve 25. Is moved to the advance mode position. Instead of step 810, the CPU 26 determines whether or not the exhaust-side relative rotation phase has become the intermediate lock phase MLP. If the exhaust-side relative rotational phase is the intermediate lock phase MLP, the CPU 26 proceeds to step 815 to move the spool position of the hydraulic control valve 25 to the lock mode position. On the other hand, if the exhaust-side relative rotation phase is not the intermediate lock phase MLP, the CPU 26 proceeds to step 865.

  Through the above processing, the CPU 26 stores information (completed information or incomplete information) indicating whether or not “the exhaust-side relative rotational phase has become the intermediate lock phase MLP before the internal combustion engine 1 stops” in the backup memory 29. Can be remembered. In other words, the information stored in the backup memory 29 in the routine shown in FIG. 8 is that the relative position of the vane rotor 50 to the housing rotor 40 is mechanically fixed by the intermediate lock mechanism 60 until the internal combustion engine 1 stops. This is information indicating whether or not it has been done.

  Further, the CPU 26 can make the intake side relative rotation phase the most retarded phase when the exhaust side relative rotation phase is not the intermediate lock phase MLP before the internal combustion engine 1 stops. This eliminates the need to change the intake-side relative rotation phase to the most retarded angle phase when starting the internal combustion engine 1, so that the crank angle can be determined earlier by the second determining means.

  When the CPU 26 receives a request for starting the internal combustion engine 1, the CPU 26 proceeds to step 900, starts the routine shown in FIG. 9, and proceeds to step 905. The start request for the internal combustion engine 1 is generated when a predetermined operation for the driver to start the internal combustion engine 1 (an operation for changing an ignition key switch (not shown) from an off position to an on position) is performed. . Alternatively, when the internal combustion engine 1 is mounted on a hybrid vehicle, the start request is generated from the power management ECU of the hybrid vehicle. Further, when the internal combustion engine 1 is mounted on a vehicle having a start and stop function, the start request is generated when an automatic start condition for the internal combustion engine 1 is satisfied.

  In step 905, the CPU 26 reads information stored in the backup memory 29 and proceeds to step 910. In step 910, the CPU 26 determines whether the information read in step 905 is completion information.

  If the information read in step 905 is completion information (that is, “the exhaust side relative rotational phase is intermediate by the intermediate lock mechanism 60 because the exhaust side relative rotational phase has become the intermediate lock phase MLP before the internal combustion engine 1 stops. CPU 26 determines “Yes” in Step 910 and proceeds to Step 915. In step 915, the CPU 26 determines the crank angle using the first determination means described above, proceeds to step 995, and ends this routine.

  On the other hand, if the information read in step 905 is not complete information, that is, if the information read in step 905 is incomplete information, the CPU 26 determines “No” in step 910 and proceeds to step 920. In step 920, the CPU 26 controls an electric motor (not shown) of the intake side valve timing varying device 8 so that the intake side relative rotational phase changes to the retard side.

  If the exhaust-side relative rotation phase is not the intermediate lock phase MLP before the internal combustion engine 1 stops, the intake-side relative rotation phase is set to the most retarded angle phase in the stop process described above. When the intake-side relative rotation phase is the most retarded angle phase, the relative movement of the output shaft (not shown) that rotates in synchronization with the intake-side camshaft 6 toward the retarded side with respect to the sprocket 4 is restricted. In step 920, the electric motor is controlled so that the intake-side relative rotation phase changes to the retarded angle side, so that the intake-side relative rotation phase is maintained at the most retarded angle phase. As a result, it is possible to prevent the intake-side relative rotation phase from deviating from the most retarded phase, and the crank angle can be accurately determined.

  After step 920, the CPU 26 determines the crank angle in step 925 using the second determining means described above, proceeds to step 995, and ends this routine.

  As a result of the above processing, the present control device performs the first determination means or the first determination when the internal combustion engine 1 is started, regardless of whether the exhaust-side relative rotational phase is the intermediate lock phase MLP before the internal combustion engine 1 stops. (2) The crank angle is determined using the determination means (that is, based on the cam signal). As a result, the present control device can quickly determine the crank angle, and can quickly determine the cylinder that first generates combustion after the cranking starts (that is, the cylinder that is ignited after fuel injection). For this reason, the start accompanying combustion of the internal combustion engine 1 can be accelerated.

  Further, the present control device provides a second determinator that needs to control the electric motor when starting the internal combustion engine 1 only when the exhaust side relative rotational phase does not become the intermediate lock phase MLP before the internal combustion engine 1 stops. Use to confirm the crank angle. That is, when the exhaust-side relative rotational phase becomes the intermediate lock phase MLP before the internal combustion engine 1 stops, the present control device sets the crank angle using the first determination means that does not require control of the electric motor. Determine.

  The process of determining the crank angle using the second determining means needs to operate the electric motor in order to change the intake side relative rotation phase to the most retarded angle phase and maintain the intake side relative rotation phase at the most retarded angle phase. There is. For this reason, the process of determining the crank angle using the second determining means consumes more power than the process of determining the crank angle using the first determining means. This control device is used only when the crank angle cannot be determined without using the second determining means (that is, only when the exhaust-side relative rotational phase does not become the intermediate lock phase MLP before the internal combustion engine 1 stops). Then, the crank angle is determined using the second determining means that consumes a large amount of power. As a result, if the internal combustion engine 1 is started a plurality of times, the average power consumption for determining the crank angle when the internal combustion engine 1 is started can be reduced, and deterioration of fuel consumption can be prevented.

  The present control device determines the crank angle by the third determining means after performing the process of determining the crank angle using the first determining means or the second determining means and starting the internal combustion engine 1. The control apparatus determines the crank angle by the third determining means until the internal combustion engine 1 is stopped thereafter.

<Modification>
Next, a modification of the control device according to the above embodiment will be described. This modification is different from the above embodiment in the following points.
(1) The intake side valve timing variable device 8 is a hydraulic drive type, and the exhaust side valve timing variable device 9 is an electric drive type.
(2) The CPU 26 executes the routine shown in the flowchart of FIG. 10 instead of the routine shown in FIG. 8 and the routine shown in the flowchart of FIG. 11 instead of the routine shown in FIG.
Hereinafter, this difference will be mainly described.

  The configuration of hydraulic drive of the intake side valve timing varying device 8 of the present modification is the same as the configuration of hydraulic drive of the exhaust side valve timing varying device 9 of the above embodiment. Furthermore, the configuration of the electric drive of the exhaust side valve timing variable device 9 of the present modification is the same as the configuration of the electric drive of the intake side valve timing variable device 8 of the above embodiment.

  When the CPU 26 receives a stop request for the internal combustion engine 1 in a state where the intake-side relative rotation phase is advanced from the intermediate lock phase MLP, the CPU 26 executes the stop process shown in FIG. In FIG. 10, steps for performing the same processing as the steps shown in FIG. 8 are given the reference numerals attached to such steps in FIG. 8, and description of those steps will be omitted as appropriate.

  When the CPU 26 receives a request to stop the internal combustion engine 1, the CPU 26 starts processing from step 1000 in FIG. 10, proceeds to step 805, and moves the spool position of the hydraulic control valve 25 to the retard mode position. As a result, the intake side relative rotational phase is retarded. Thereafter, the CPU 26 proceeds to step 1005 to determine whether or not the intake side relative rotation phase has become the stop preparation phase SPP.

  When the intake-side relative rotation phase becomes the stop preparation phase SPP, the CPU 26 determines “Yes” in step 1005 and moves the spool position of the hydraulic control valve 25 to the lock mode position in step 815. . Thereby, the state of the lock pin of the intermediate lock mechanism 60 of the intake side valve timing varying device 8 becomes the operating state. As a result, the intermediate lock mechanism 60 is in a state where the intake side relative rotation phase can be fixed to the intermediate lock phase MLP.

  Thereafter, in step 1010, the CPU 26 determines whether or not the intake side relative rotation phase has become the intermediate lock phase MLP. If the intake side relative rotation phase becomes the intermediate lock phase MLP, the CPU 26 determines “Yes” in step 1010, proceeds to step 825, stores the completion information in the backup memory 29, and supplies power in step 830. Is stopped, the process proceeds to Step 1095, and this routine is terminated.

  On the other hand, if the intake-side relative rotation phase is not the intermediate lock phase MLP, the CPU 26 makes a “No” determination at step 1010 to proceed to step 835 where the number N of crank signal inputs per predetermined time is a threshold value. It is determined whether N1th or less.

  When the input number N of crank signals per predetermined time is larger than the threshold value N1th, the CPU 26 determines “No” in step 835 and returns to step 1010.

  On the other hand, when the input number N of crank signals per predetermined time is equal to or less than the threshold value N1th, the CPU 26 determines “Yes” in step 835, executes steps 840 and 845 in this order, and returns to step 1015. move on. In step 1015, CPU 26 determines whether or not the value of timer TMR is equal to or smaller than a predetermined threshold value TMR2th corresponding to predetermined time T2. The predetermined time T2 is set to be longer than the time required for the exhaust side relative rotation phase to change from the most retarded phase to the most advanced angle phase, and may be the same value as the predetermined time T1 or a different value. May be.

  If the value of the timer TMR is equal to or less than the threshold value TMR2th, the CPU 26 determines “Yes” in step 1015 and proceeds to step 1020. In step 1020, the CPU 26 controls an electric motor (not shown) of the exhaust side valve timing varying device 9 so that the exhaust side relative rotational phase changes to the advance side, and returns to step 845. Thus, the CPU 26 continues to control the electric motor so that the exhaust side relative rotation phase changes to the advance side until the value of the timer TMR becomes larger than the threshold value TMR2th corresponding to the predetermined time T2. As a result, the exhaust-side relative rotation phase can be reliably changed to the most advanced angle phase during the predetermined time T2. Since the overlap between ExVVT and InVVT decreases as the exhaust camshaft 7 advances with respect to the crankshaft 2, the exhaust side relative rotation phase is not the most retarded phase but the most advanced angle phase in step 1020. To change.

  On the other hand, if the value of timer TMR is greater than threshold value TMR2th, CPU 26 determines “No” in step 1015, initializes timer TMR in step 860, and stops power supply in step 830. Then, the process proceeds to Step 1095, and this routine is terminated.

  In the stop process when the CPU 26 receives a stop request for the internal combustion engine 1 in a state where the intake side relative rotation phase is retarded from the intermediate lock phase MLP, the CPU 26 determines whether the hydraulic control valve 25 is in step 805. Move the spool position to the advance mode position. Instead of step 1005, the CPU 26 determines whether or not the intake-side relative rotation phase has become the intermediate lock phase MLP. If the intake relative rotation phase is the intermediate lock phase MLP, the CPU 26 proceeds to step 815 to move the spool position of the hydraulic control valve 25 to the lock mode position. On the other hand, if the intake relative rotation phase is not the intermediate lock phase MLP, the CPU 26 proceeds to step 865.

  When the CPU 26 receives a start request for the internal combustion engine 1, the CPU 26 executes the start process shown in FIG. In FIG. 11, steps for performing the same processing as the steps shown in FIG. 9 are denoted by reference numerals attached to such steps in FIG. 9, and description of those steps is omitted as appropriate.

  When the CPU 26 receives a start request for the internal combustion engine 1, the CPU 26 starts processing from step 1100 in FIG. 11, proceeds to step 905, reads information stored in the backup memory 29, and proceeds to step 910. In step 910, the CPU 26 determines whether the information read in step 905 is completion information.

  If the information read in step 910 is completion information, the CPU 26 determines “Yes” in step 910 and proceeds to step 915. In step 915, the CPU 26 determines the crank angle using the first determination means described above, proceeds to step 1195, and ends this routine.

  On the other hand, if the information read in step 910 is not complete information, that is, if the information read in step 905 is incomplete information, the CPU 26 determines “No” in step 910 and proceeds to step 1105. In step 1105, the CPU 26 controls an electric motor (not shown) of the exhaust side valve timing varying device 9 so that the exhaust side relative rotational phase changes to the advance side.

  If the intake-side relative rotation phase is not the intermediate lock phase MLP before the internal combustion engine 1 is stopped, the exhaust-side relative rotation phase is set to the most advanced angle phase in the stop process described above. When the exhaust-side relative rotation phase is the most advanced angle phase, the relative movement of the exhaust-side camshaft 7 with respect to the crankshaft 2 is restricted. In step 1105, the electric motor is controlled so that the exhaust-side relative rotation phase changes to the advance side, so the exhaust-side relative rotation phase is maintained at the most advanced angle phase. Thereby, it is possible to prevent the exhaust side relative rotation phase from deviating from the most advanced angle phase, and to accurately determine the crank angle.

  When the sprocket is rotated by the rotation of the crankshaft 2 due to the structure of the electrically driven valve timing variable device, a force acts on the retard side of the output shaft that rotates in synchronization with the camshaft. For this reason, when no force is applied to the output shaft by the electric motor, the output shaft moves to the retard side. Therefore, when the exhaust side valve timing varying device 9 is electrically driven as in this modification, in order to change the exhaust side relative rotational phase to the most advanced angle phase in step 1105, the electric motor is a sprocket. The force must be applied to the advance side in the opposite direction to the retard side force acting by the rotation of 4. For this reason, in this modification, power consumption becomes larger than the case where the exhaust side relative rotation phase is changed to the most retarded angle phase as in the above embodiment. Therefore, it is desirable from the viewpoint of reducing power consumption that the intake side valve timing varying device 8 is electrically driven as in the above embodiment.

  After step 1105, the CPU 26 determines the crank angle in step 925 using the second determining means described above, proceeds to step 1195, and ends this routine.

  The present invention is not limited to the above-described embodiments, and various modifications of the present invention can be employed. The intermediate lock phase MLP in the intermediate lock mechanism 60 is a phase from the most advanced angle phase to the most retarded angle phase, and may be any phase as long as the internal combustion engine 1 can be started.

  In the above embodiment, the cam rotor 31 having the same configuration is attached to the intake side cam shaft 6 and the exhaust side cam shaft 7 at the same attachment angle, and the relative positional relationship between each cam rotor 31 and each cam angle sensor 10 is the same. However, the same cam rotor 31 may be attached to each cam shaft at a different attachment angle, or a cam rotor having a different configuration may be attached to each cam shaft. Furthermore, the relative positional relationship between each cam rotor 31 and each cam angle sensor 10 may be different.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Crankshaft, 6 ... Intake side camshaft, 7 ... Exhaust side camshaft, 8 ... Intake side valve timing variable device, 9 ... Exhaust side valve timing variable device, 10 ... Intake side cam angle sensor, DESCRIPTION OF SYMBOLS 11 ... Exhaust side cam angle sensor, 12 ... Crank angle sensor, 20 ... ECU, 21 ... Crank rotor, 22 ... Teeth, 23 ... Missing tooth part, 25 ... Hydraulic control valve, 26 ... CPU, 27 ... ROM, 28 ... RAM , 29 ... backup memory, 31 ... cam rotor, 40 ... housing rotor, 50 ... vane rotor, 60 ... intermediate locking mechanism.

Claims (1)

Crank that is the rotation angle of the crankshaft from the reference crank angle at the time when the piston of any cylinder of the four-cycle internal combustion engine is at compression top dead center or advanced by a predetermined crank angle within the range of 720 ° from that time A control device for an internal combustion engine that determines an angle and controls the internal combustion engine based on the determined crank angle,
The internal combustion engine
The crankshaft;
An intake-side camshaft to which a cam for opening and closing an intake valve of the internal combustion engine is attached, and rotation of the crankshaft is transmitted so that the crankshaft rotates once when the crankshaft rotates twice;
An exhaust camshaft to which a cam for opening and closing an exhaust valve of the internal combustion engine is attached and the rotation of the crankshaft is transmitted so that the crankshaft rotates once when the crankshaft rotates twice;
The first relative rotation phase of one of the intake camshaft and the exhaust camshaft with respect to the crankshaft is advanced or retarded by hydraulic drive and attached to the first camshaft. Hydraulically driven valve timing variable means for changing the opening and closing timing of the valve;
The second relative rotational phase of the other second camshaft of the intake side camshaft and the exhaust side camshaft with respect to the crankshaft is advanced or retarded by an electric motor and attached to the second camshaft. Electrically driven valve timing variable means for changing the opening and closing timing of the valve;
A crank rotor that includes a plurality of teeth provided at equal intervals on the outer periphery, and a missing tooth portion that is a region where the teeth formed on a part of the outer periphery are not provided, and that rotates synchronously with the crankshaft;
A plurality of convex portions and a plurality of concave portions are alternately provided on the outer periphery, the plurality of convex portions are provided over an angle corresponding to a crank angle having a different width, and the plurality of concave portions correspond to a crank angle having a different width. A first cam rotor that is provided over an angle that rotates in synchronization with the first cam shaft;
A plurality of convex portions and a plurality of concave portions are alternately provided on the outer periphery, the plurality of convex portions are provided over an angle corresponding to a crank angle having a different width, and the plurality of concave portions correspond to a crank angle having a different width. A second cam rotor that is provided over an angle that rotates in synchronization with the second cam shaft;
A crank angle sensor unit that outputs a pulse that is a crank signal during a period in which the teeth of the crank rotor pass through the crank rotor tooth detection unit;
A first cam angle sensor unit that outputs a pulse that is a first cam signal during a period in which the convex part of the first cam rotor passes through the first cam rotor convex part detection unit;
A second cam angle sensor unit that outputs a pulse that is a second cam signal during a period in which the convex part of the second cam rotor passes through the second cam rotor convex part detection unit,
The hydraulically driven valve timing varying means is
A first rotating body that rotates synchronously with the crankshaft;
The first rotary body is arranged coaxially, rotates synchronously with the first camshaft, and can change a relative rotational position with respect to the first rotary body in order to change the first relative rotational phase. Two rotating bodies,
A hydraulic drive mechanism for changing the relative rotational position of the second rotary body with respect to the first rotary body by hydraulic drive;
When the first relative rotation phase becomes a predetermined lock phase, the relative rotation position of the second rotation body with respect to the first rotation body may be mechanically fixed to the rotation position that becomes the lock phase. A possible locking mechanism,
The electrically driven valve timing varying means is
When the second relative rotation phase is the most advanced angle phase, the second relative rotation phase is mechanically restricted from changing to the advance angle side, and the second relative rotation phase is the most retarded angle phase. In some cases, a regulation unit that mechanically regulates that the second relative rotation phase changes to the retard side,
The control device corresponds to a crank angle corresponding to each rising point of the first cam signal and a falling point of the first cam signal when the first relative rotational phase is a predetermined reference phase. The crank angle is stored in advance, and the crank angle corresponding to each rising point of the second cam signal when the second relative rotational phase is a predetermined reference phase, and each rising edge of the second cam signal. The crank angle corresponding to the time point of lowering is stored in advance,
The control device includes:
A backup memory for holding stored information even when the internal combustion engine is stopped;
Based on the number of inputs of the crank signal from the rise of the first cam signal to the fall following the rise, or from the fall of the first cam signal to the rise following the fall, The first cam rotor convex portion detecting portion that has passed through the first cam rotor convex portion detecting portion is identified, and the first convex portion when the identified convex portion has finished passing through the first cam rotor convex portion detecting portion. Based on the crank angle stored in advance corresponding to the falling edge of the cam signal or the rising edge of the first cam signal at the time when the specified concave portion has passed through the first cam rotor convex portion detector. First determining means for determining the angle;
Based on the number of inputs of the crank signal from the rise of the second cam signal to the fall following the rise, or from the fall of the second cam signal to the rise following the fall, A second portion at the time when the convex portion or concave portion of the second cam rotor that has passed through the second cam rotor convex portion detecting portion is specified and the specified convex portion has passed through the second cam rotor convex portion detecting portion. Based on the crank angle stored in advance corresponding to the falling edge of the cam signal or the rising edge of the second cam signal at the time when the specified concave portion has passed through the second cam rotor convex portion detector. A second determining means for determining the angle;
When receiving a request to stop the internal combustion engine, a stop processing unit that executes processing at the time of stopping the internal combustion engine;
When receiving a request for starting the internal combustion engine, a start processing unit that executes processing at the time of starting the internal combustion engine,
The stop processing unit
Changing the relative rotational position of the second rotating body with respect to the first rotating body using the hydraulic drive mechanism so that the first relative rotation phase is the lock phase;
Controlling the locking mechanism to mechanically fix the relative rotational position of the second rotating body with respect to the first rotating body when the first relative rotating phase becomes the lock phase;
It is determined whether or not the first relative rotational phase has become the lock phase before the internal combustion engine stops, and the determination result is stored in the backup memory,
If the first relative rotational phase does not become the lock phase before the internal combustion engine stops, the power supply to the control device and the electric motor is extended for a predetermined time,
The electric motor is configured to control the second relative rotational phase to be one of the most advanced phase and the most retarded phase while the power supply is extended,
The predetermined time for extending the power supply is set to a value equal to or longer than the time required for the second relative rotational phase to change from the other phase to the one of the most advanced phase and the most retarded phase. And
The start processing unit
When the determination result stored in the backup memory indicates that the first relative rotational phase has become the lock phase before the internal combustion engine stops, the crank angle is determined using the first determination means. Confirm,
When the determination result stored in the backup memory indicates that the first relative rotational phase is not the lock phase before the internal combustion engine stops, the one phase is the most advanced angle phase. If there is, the electric motor is rotated so that the second relative rotation phase changes to the advance side, and if the one phase is the most retarded phase, the second relative rotation phase is the retard angle. The crank angle is determined using the second determination means while rotating the electric motor to change to the side,
Control device for internal combustion engine.

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