JP2018197521A - Control device for internal combustion engine - Google Patents

Abstract

To provide a control device for actualizing easy start of an internal combustion engine by speeding up the rotation of a crankshaft at the start.SOLUTION: An internal combustion engine E includes cylinders each having a piston 4 for reciprocating in linkage with the rotation of a crankshaft 1 and an intake valve Va and an exhaust valve Vb for opening/closing a combustion chamber, a starter motor 15 for driving the rotation of the crankshaft 1, and a valve opening/closing timing control mechanism VT for setting an opening/closing timing for the intake valve Va through the drive of an electric actuator M. At the time of cranking, the control device controls the electric actuator M to advance the opening timing for the exhaust valve Vb of part of the plurality of cylinders being in an exhaust stroke and retard the closing timing for the exhaust valve Vb.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for an internal combustion engine.

  Patent Document 1 describes a technology that includes a valve timing adjustment mechanism that controls the opening / closing timing of an intake valve of an internal combustion engine, and that sets the opening / closing timing to the most retarded timing to keep the pressure in the combustion chamber low when the internal combustion engine is started. Has been.

  Further, Patent Document 2 includes a valve opening / closing timing control mechanism in an intake valve or an exhaust valve of an internal combustion engine, and the valve opening / closing timing control mechanism is set to a most retarded phase state, thereby compressing an air-fuel mixture in a combustion chamber. A technique is described in which the ratio is reduced (so-called decompression state) and the compression ratio of the air-fuel mixture in the combustion chamber is reduced to reduce engine vibration.

  This Patent Document 2 describes a control mode in which the internal combustion engine is stopped by setting the valve opening / closing timing control mechanism to the most retarded phase while the idle stop condition is satisfied.

Japanese Patent Laid-Open No. 11-30134 JP 2007-64127 A

  In order to start the internal combustion engine stably, it is important to perform combustion in the combustion chamber with the crankshaft rotating at a high speed. In order to drive the crankshaft at a high speed when starting the internal combustion engine, it is conceivable to use a starter motor having a large capacity. However, conventionally, as described in Patent Document 1 and Patent Document 2, the intake valve is opened and closed. A valve opening / closing timing control mechanism that controls the timing is also set to the most retarded phase.

  In other words, by setting the valve opening / closing timing control mechanism that controls the opening / closing timing of the intake valve to the most retarded phase, the compression ratio of the air in the combustion chamber during cranking is reduced and the crankshaft cranking speed is increased. It aims to make it easier.

  However, the region where the compression ratio of the air in the combustion chamber can be reduced during cranking is only the process from the bottom dead center to the top dead center, and the intake amount is reduced when the most retarded angle is set. Therefore, it was possible to imagine increasing the negative pressure and increasing the load in the process until the piston reached the bottom dead center.

  For these reasons, there is a need for a control device that facilitates starting by increasing the rotation speed of the crankshaft when starting the internal combustion engine.

A feature of the present invention is that a plurality of cylinders having a piston that reciprocates in a cylinder in association with rotation of a crankshaft, and an intake valve and an exhaust valve that open and close a combustion chamber in association with rotation of the crankshaft, An internal combustion engine comprising: a starter motor that drives and rotates a crankshaft; and a valve opening / closing timing control mechanism that sets an opening / closing timing of the exhaust valve by driving an electric actuator;
When cranking is performed by the starter motor, EVO, which is the opening timing of the exhaust valve, is advanced and EVC, which is the closing timing of the exhaust valve, is delayed for those in the exhaust stroke among the plurality of cylinders. The point is to control the electric actuator so as to make the angle.

According to this characteristic configuration, when cranking is performed, exhaust of the combustion chamber in the expansion stroke is performed at an early stage by advancing the EVO that is the opening timing for the exhaust valve in the exhaust stroke, Pump loss in this expansion stroke is reduced. Further, by retarding the EVC, which is the closing timing of the exhaust valve, it is possible to increase, for example, an overlap with the intake valve when shifting from the expansion stroke to the intake stroke, and pump loss in the intake stroke Reduce. In other words, the valve opening / closing timing control mechanism that controls the opening / closing timing with the driving force of the electric actuator can control the opening / closing timing very quickly. As a result, the load acting on the crankshaft is reduced and the crankshaft can be rotated at a high speed.
As a result, a control device has been constructed that facilitates starting by speeding up the rotation of the crankshaft when starting the internal combustion engine.

  As another configuration, after the first combustion of the cylinder, the order of which is set to burn last among the plurality of cylinders, is performed, the electric actuator is controlled based on the combustion speed in the combustion chamber. May be.

  According to this, after the first combustion of the cylinders that are set to burn at the end of the plurality of cylinders is performed, the exhaust valve is opened and closed at the optimum timing corresponding to the combustion speed in the combustion chamber It becomes possible to control.

It is a figure which shows the cross section of an engine, and a control unit. It is sectional drawing of a valve opening / closing timing control mechanism. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is a disassembled perspective view of a valve opening / closing timing control mechanism. It is a flowchart of a starting routine. It is a timing diagram which shows the opening / closing timing of a valve opening / closing timing control mechanism. It is a timing chart which shows the opening / closing operation | movement of an exhaust valve and an intake valve. It is a timing chart which shows the opening / closing operation | movement of another embodiment (a). It is a timing chart which shows the opening / closing operation | movement of another embodiment (b).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Basic configuration]
As shown in FIG. 1, an intake-side valve opening / closing timing control mechanism VTa for setting an opening / closing timing of an intake valve Va of an engine E as an internal combustion engine, and an exhaust-side valve opening / closing timing control for setting an opening / closing timing of an exhaust valve Vb. An engine control device 40 that functions as an ECU is configured to control the mechanism VTb and the engine E.

  The engine E (an example of an internal combustion engine) shown in FIGS. 1 and 2 is assumed to be provided in a vehicle such as a passenger car. In this engine E, a cylinder head 3 is connected to an upper portion of a cylinder block 2 that supports a crankshaft 1, pistons 4 are slidably accommodated in a plurality of cylinder bores formed in the cylinder block 2, and the piston 4 is connected to a connecting rod. 5 is connected to the crankshaft 1 to form a four-cycle type.

  In this engine E, there are # 1, # 2, # 3, and # 4 cylinders (shown as # 1, # 2, # 3, and # 4 in FIG. 2) from one end to the other. The combustion chamber is formed between the piston 4 and the cylinder head 3 in the internal space of the cylinder.

  The cylinder head 3 is provided with an intake valve Va that is opened when the combustion chamber is inhaled and an exhaust valve Vb that is opened when the combustion gas is discharged from the combustion chamber, and an intake valve that controls the intake valve Va is provided above the cylinder head 3. A camshaft 7 and an exhaust camshaft 8 that controls the exhaust valve Vb are provided. The timing chain 6 is wound around the output sprocket 1S of the crankshaft 1 and the sprocket 21S of the drive case 21 of the intake side valve opening / closing timing control mechanism VTa and the exhaust side valve opening / closing timing control mechanism VTb. .

  Further, the cylinder head 3 is provided with an injector 9 and a spark plug 10 for injecting fuel into the combustion chamber. An intake manifold 11 that supplies air to the combustion chamber via an intake valve Va and an exhaust manifold 12 that sends combustion gas from the combustion chamber via an exhaust valve Vb are connected to the cylinder head 3.

  The engine E includes a starter motor 15 that drives and rotates the crankshaft 1, and a shaft sensor 16 that detects a rotation angle and a rotation speed (the number of rotations per unit time) near the crankshaft 1. . An intake side phase sensor 17 for detecting the relative rotational phase between the drive case 21 and the internal rotor 22 is provided in the vicinity of the intake side valve opening / closing timing control mechanism VTa, and the drive is provided in the vicinity of the exhaust side valve opening / closing timing control mechanism VTb. An exhaust-side phase sensor 18 that detects a relative rotational phase between the case 21 and the internal rotor 22 is provided.

  The engine E includes a cylinder discrimination unit (not shown) that discriminates a cylinder to be burned, and the shaft sensor 16 is configured by using a part of the configuration of the cylinder discrimination unit.

  The engine control device 40 functions as an ECU that controls the engine E, and includes a start control unit 41, a phase control unit 42, and a combustion speed estimation unit 43. The start control unit 41 controls the start of the engine E. The phase control unit 42 controls the relative rotation phase between the intake side valve opening / closing timing control mechanism VTa and the exhaust side valve opening / closing timing control mechanism VTb. The combustion speed estimation unit 43 estimates the combustion speed in the combustion chamber. Details and control mode of the engine control device 40 will be described later.

[Valve opening / closing timing control mechanism]
Since the intake-side valve opening / closing timing control mechanism VTa and the exhaust-side valve opening / closing timing control mechanism VTb have a common configuration, these upper concepts are referred to as a valve opening / closing timing control mechanism VT. The valve opening / closing timing control mechanism VT controls the opening / closing timing of the corresponding valve by the driving force of the phase control motor M as an electric actuator.

  2 to 5 show a valve opening / closing timing control mechanism TVa on the intake side, and this valve opening / closing timing control mechanism TVa has a drive case 21 and an internal rotor 22, and the relative rotational phases thereof are phase-shifted. A phase adjustment unit that is set by the driving force of the control motor M is provided.

  The drive case 21 has a sprocket 21 </ b> S formed on the outer periphery and is disposed coaxially with the rotational axis X of the intake camshaft 7. The internal rotor 22 is included so as to be rotatable relative to the drive case 21, and is connected and fixed to the intake camshaft 7 by a connecting bolt 23. A phase adjuster is disposed between the drive case 21 and the internal rotor 22, a front plate 24 is disposed at a position covering the opening of the drive case 21, and this is fastened to the drive case 21 with a plurality of fastening bolts 25. Yes. In the exhaust-side valve opening / closing timing control mechanism VTb, the internal rotor 22 is connected to the exhaust camshaft 8.

  In the valve opening / closing timing control mechanism VTa, the whole is rotated in the driving rotation direction S by the driving force from the timing chain 6 as shown in FIG. The direction in which the relative rotational phase of the internal rotor 22 with respect to the drive case 21 is displaced in the same direction as the drive rotation direction S by the driving force of the phase control motor M is referred to as the advance angle direction Sa, and the displacement in the opposite direction is delayed. This is referred to as the angular direction Sb.

[Valve opening / closing timing control mechanism: phase adjuster]
The phase adjustment unit includes a plurality of internal teeth 26T integrally formed on the inner periphery of the inner rotor 22, and includes a ring gear 26 arranged coaxially with the rotation axis X, and a plurality of meshes for meshing with the ring gear 26. And the inner gear 27 disposed coaxially with the eccentric shaft core Y in a posture parallel to the rotational shaft core X, and includes the eccentric cam body 28 and the joint portion J. .

  In this phase adjustment unit, the number of teeth of the outer tooth portion 27T of the inner gear 27 is smaller by one than the number of teeth of the inner tooth portion 26T of the ring gear 26.

  Further, the joint portion J is configured as an Oldham joint that prevents relative rotation between the drive case 21 and the internal rotor 22 while allowing the internal rotor 22 to be displaced in a direction perpendicular to the rotation axis X with respect to the drive case 21. Has been.

  The eccentric cam body 28 is supported by the first bearing 31 with respect to the front plate 24 so as to rotate on the same axis as the rotation axis X. The eccentric cam body 28 is integrally formed with an eccentric cam surface 28A centering on an eccentric shaft core Y in a posture parallel to the rotation shaft core X, and an inner gear is connected to the eccentric cam surface 28A via a second bearing 32. 27 is rotatably supported. In addition, a spring body 29 is fitted into a recess formed in the eccentric cam surface 28 </ b> A, and the urging force of the spring body 29 is applied to the inner gear 27 via the second bearing 32.

  The eccentric cam body 28 has a tubular shape as a whole, and a pair of engagement grooves 28B are formed in an inner periphery in a posture that is parallel to the rotation axis X.

  Thereby, a part of the outer tooth portion 27T of the inner gear 27 is engaged with a part of the inner tooth portion 26T of the ring gear 26. In addition, although the 1st bearing 31 and the 2nd bearing 32 are comprised with a ball bearing, you may comprise with a bush.

  The joint portion J has a joint member 33 formed by pressing a plate material, and a pair of engagement arms 33A formed on the joint member 33 is engaged with the engagement groove portion 21G of the drive case 21, so that the joint The pair of engaging recesses 33 </ b> B formed in the member 33 are configured to engage with the engaging protrusions 27 </ b> U of the inner gear 27.

  That is, the joint member 33 has a central portion formed in an annular shape, and a pair of engaging arms 33A projecting outward from the annular central portion, and is connected to a space in the annular central portion. The engaging recess 33B is formed.

  In the joint portion J, the joint member 33 is freely displaceable in a linear direction connecting the pair of engagement groove portions 21G of the drive case 21, and the inner gear 27 connects the pair of engagement protrusions 27U to the joint member 33. Displaceable in the direction.

  The phase control motor M is supported by the engine E and includes an engagement pin 34 provided in a posture orthogonal to the output shaft Ma. The engagement pin 34 is connected to the inner periphery of the eccentric cam body 28. It fits in the joint groove 28B. As the phase control motor M, a brushless DC motor is used, but a synchronous motor such as a stepping motor may be used.

  As a result, when the operation mode is considered with the engine E stopped, when the eccentric cam body 28 is rotated by the driving force of the phase control motor M, the eccentric cam surface 28A rotates about the rotation axis X, With this rotation, the inner gear 27 starts to revolve around the rotation axis X. During this revolution, the engagement position between the outer tooth portion 27T of the inner gear 27 and the inner tooth portion 26T of the ring gear 26 is displaced along the inner periphery of the ring gear 26, so that the inner gear 27 has a force to rotate around the eccentric shaft core Y. Works.

  That is, when the inner gear 27 revolves only once, an angle (1) corresponding to the difference (tooth number difference) between the number of teeth of the inner tooth portion 26T of the ring gear 26 and the number of teeth of the outer tooth portion 27T of the inner gear 27. A rotational force (rotational force) is applied to rotate the inner gear 27 by an angle corresponding to the tooth.

  As described above, since the joint portion J has a structure that restricts the rotation of the inner gear 27 with respect to the drive case 21, the inner gear 27 does not rotate with respect to the drive case 21, and the rotational force acting on the inner gear 27 The ring gear 26 rotates with respect to the drive case 21, and the internal rotor 22 rotates relative to the ring gear 26, so that the rotation phase of the intake camshaft 7 relative to the drive case 21 is adjusted.

  In particular, when the inner gear 27 revolves only one rotation around the rotation axis X, the intake camshaft 7 is different from the drive case 21 in the number of teeth of the outer teeth 27T of the inner gear 27 (the number of teeth difference). Adjustment is realized with a large reduction ratio since the rotation is performed by an angle corresponding to.

[Valve opening / closing timing control mechanism: Overview of phase adjustment]
Taking phase adjustment by the intake side valve opening / closing timing control mechanism VTa as an example, the phase control unit 42 of the engine control device 40 outputs the output shaft of the phase control motor M in the same direction as the rotational speed of the intake camshaft 7. The relative rotation phase between the drive case 21 and the internal rotor 22 is maintained by driving and rotating Ma.

  Further, the relative rotational phase is displaced in the advance direction Sa or the retard direction Sb by increasing or decreasing the rotational speed of the phase control motor M with reference to the rotational speed of the intake camshaft 7. The displacement direction of the relative rotational phase with respect to the increase or decrease of the rotational speed of the phase control motor M (either the advance angle direction Sa or the retard angle direction Sb) is determined by the gear configuration of the phase adjustment unit.

  In particular, since the valve opening / closing timing control mechanism VT displaces the relative rotational phase by the driving force of the phase control motor M, the valve opening / closing timing control mechanism VT can operate at a higher speed than the one that realizes the displacement by hydraulic pressure. Even in a situation where the hydraulic pressure is not sufficient as in the case of time, it is possible to quickly set the required rotation phase.

(Control configuration)
As shown in FIG. 1, the engine control device 40 receives detection signals from the shaft sensor 16, the intake side phase sensor 17, and the exhaust side phase sensor 18, and phase control motors for the intake side and the exhaust side. A control signal is output to M and the starter motor 15, and further, a control signal is output to the combustion management unit 19 that controls the injector 9 and the spark plug 10.

  The start control unit 41 controls cranking by controlling the starter motor 15. The phase control unit 42 controls the phase control motor M of the intake side valve opening / closing timing control mechanism VTa and the phase control motor M of the exhaust side valve opening / closing timing control mechanism VTb, thereby controlling the opening / closing timing of the intake valve Va. Setting and setting of the opening / closing timing of the exhaust valve Vb are made possible. The combustion speed estimation unit 43 estimates the combustion speed in the combustion chamber.

  In the following control, as shown in FIGS. 7 and 8, the direction in which the IVO that is the opening timing of the intake valve Va and the EVO that is the opening timing of the exhaust valve Vb are advanced is called an advance angle direction (advance angle side). The reverse direction is described as the retard direction (retard side).

  Further, when the combustion speed estimation unit 43 estimates the combustion speed, the combustion speed is estimated based on the increasing tendency of the rotational speed of the crankshaft 1 detected by the shaft sensor 16 with reference to the ignition timing by the spark plug 10. This technique is adopted. The combustion speed estimation unit 43 may be provided with a dedicated sensor for measuring the combustion speed, referring to table data set in advance when estimating the combustion speed, or acquired at a plurality of timings. It is possible to perform processing based on the detection signal of the shaft sensor 16.

  It is assumed that the start control unit 41, the phase control unit 42, and the combustion speed estimation unit 43 of the engine control device 40 are configured by software, but these are hardware configured by a circuit having logic or the like. It may be configured, or may be configured by a combination of software and hardware.

  The combustion management unit 19 manages the operation of pumps that supply fuel to the injector 9 and manages the ignition sequence and ignition timing by controlling an ignition circuit that supplies electric power to the spark plug 10.

[Control form]
When the control signal for starting the engine E is acquired as shown in the flowchart of FIG. 6, the timing diagram of FIG. 7, and the timing chart of FIG. The opening / closing timing of the mechanism VTa is set to a predetermined value, and cranking is started by driving the starter motor 15 to perform cylinder discrimination (steps # 101 to # 103).

  In step # 101, the opening / closing timing of the intake valve Va is set so that IVO, which is the opening timing of the intake valve Va, coincides with the top dead center TDC of the piston 4 as shown in FIG. In the timing diagram of FIG. 7, a region where exhaust is performed in the exhaust valve Vb is shown as an exhaust region Ex, and a region where intake is performed in the intake valve Va is shown as an intake region In.

  Next, as shown in FIGS. 7 and 8, before the exhaust valve Vb opens in each cylinder, the EVO that is the opening timing is controlled by the advance operation amount AC by the control of the exhaust valve opening / closing timing control mechanism VTb. The advance angle control is performed, and the EVC that is the closing timing after the set timing has elapsed is retarded by the retard operation amount RC (steps # 104 to # 106).

  In this control, the timing at which the exhaust valve Vb reaches full open is determined as the set timing. In this control, for each cylinder, EVO, which is the opening timing of the exhaust valve Vb, is advanced by a time corresponding to the advance operation amount AC by advance control, and EVC, which is the closing timing of the exhaust valve Vb, is delayed by retard control. By delaying the time corresponding to the angular operation amount RC, the control for extending the time during which the exhaust valve Vb is in the open state is executed.

  In the timing chart of FIG. 8, the crank angle is on the horizontal axis, and the lift amounts of the intake valve Va and the exhaust valve Vb are on the vertical axis. Further, the open / close characteristics of the exhaust valve Vb in a state in which the EVO that is the opening timing of the exhaust valve Vb and the EVC that is the closing timing are fixed at a predetermined timing are indicated by a broken line as the basic exhaust curve Ex, # 104 to # 105 It is shown as an exhaust extension curve Exe having a characteristic in which the opening time is extended by step control.

  That is, EVO, which is the opening timing of the exhaust extension curve Exe, is earlier than (EVO), which is the opening timing in the exhaust basic curve Ex, and is compared with (EVC), which is the closing timing in the exhaust basic curve Ex. The EVC, which is the closing timing of the exhaust extension curve Exe, is delayed.

  As a result, the EVO, which is the opening timing of the exhaust valve Vb, is displaced to the advance side, whereby the air in the combustion chamber is discharged early in one expansion stroke, and the pump loss in this expansion stroke is reduced. Further, when the EVC, which is the closing timing of the exhaust valve Vb in the same expansion stroke, is displaced to the retard side, and when shifting from the expansion stroke to the intake stroke, the overlap with the intake valve Va is increased to increase the intake air. Reduce pump loss in the process. As a result, the load acting on the crankshaft 1 is reduced, and the rotational speed of the crankshaft 1 can be increased.

  Next, after determining that the rotational speed of the crankshaft 1 has reached a combustible speed, combustion is started, and after the combustion in each cylinder is performed, the starter motor 15 is stopped. Then, in accordance with the combustion speed estimated by the combustion speed estimation unit 43, the exhaust valve opening / closing timing control mechanism VTb is controlled to set EVC which is the closing timing of the exhaust valve Vb (steps # 107 to # 110).

  Of these controls, in step # 108, the combustion management unit 19 performs the first combustion in a predetermined cylinder, and the combustion in each combustion chamber is performed in a set order. In this control, as shown in FIG. 8, since the EVC that is the closing timing of the exhaust extension curve Exe is set after the IVO that is the opening timing of the intake curve In, the intake valve Vb is opened when the exhaust valve Vb is open. It becomes the overlap state which Va opens.

  Since the overlap is formed in this way, in a situation where combustion in each combustion chamber is performed, the state becomes an internal EGR state in which combustion gas is sucked into the combustion chamber in the intake stroke at the intake valve Va. In this internal EGR state, the combustion gas from the previous stroke is taken into the combustion chamber, so that the temperature of the combustion chamber can be quickly increased.

  On the other hand, since the combustion gas before the first stroke is taken into the combustion chamber, the combustion speed is lowered, and the combustion may become unstable. For this reason, for example, the combustion is stabilized by controlling the opening / closing characteristics of the exhaust valve Vb to the exhaust basic curve Ex after a set time has elapsed, or by shifting the opening / closing timing in the advance direction when necessary.

  That is, since the exhaust side valve opening / closing timing control mechanism VTb has a performance capable of high-speed phase control by the phase control motor M, the EVO that is the opening timing of the exhaust valve Vb is advanced in one expansion stroke. In addition to being displaced in the advance direction by the amount AC, the control for displacing EVC, which is the closing timing of the exhaust valve Vb, in the retard direction by the retard operation amount RC is realized.

  In this control, it is ideal that EVO, which is the opening timing of the exhaust valve Vb, reaches the most advanced angle phase, and EVC, which is the closing timing, reaches the most retarded phase. Compared with the basic curve Ex, the effect of reducing the addition at the time of cranking can be obtained by controlling the EVO that is the opening timing in the advance direction and the EVC that is the closing timing in the retard direction.

  In particular, even if the opening / closing timing of the exhaust valve Vb is changed by the exhaust-side valve opening / closing timing control mechanism VTb, the intake amount in the intake stroke is not changed, so that the opening / closing timing of the exhaust-side valve opening / closing timing control mechanism VTb is controlled. Even if set arbitrarily, combustion without affecting the air-fuel ratio is enabled.

[Another embodiment]
In addition to the above-described embodiments, the present invention may be configured as follows (the components having the same functions as those of the embodiments are given the same numbers and symbols as those of the embodiments).

(A) As shown in FIG. 9, the opening / closing timing of the intake valve Va set in step # 101 of the flowchart of FIG. 6 described in the embodiment is displaced in the retarded direction (an intake retarded curve Inr described later).

  Even in the control of this alternative embodiment (a), EVO, which is the opening timing of the exhaust valve Vb, is advanced by the advance angle control by the advance operation amount AC for each cylinder, and EVC, which is the closing timing of the exhaust valve Vb. Is controlled by retarding the retarded operation amount RC by retarding control to extend the time during which the exhaust valve Vb is in the open state. Accordingly, as shown in FIG. 9, the exhaust valve Vb follows the exhaust extension curve Exe in which the EVO that is the opening timing is earlier and the EVC that is the closing timing is delayed compared to the opening timing (EVO) in the exhaust basic curve Ex. Opens and closes.

  Further, when the opening / closing characteristics of the intake valve Va in which the IVO that is the opening timing and the IVC that is the closing timing are fixed at the predetermined timing are the intake curve In, the IVO that is the opening timing is The opening / closing timing of the intake valve Va is set so that the IVC that is the closing timing is displaced toward the retarded side by the retarding operation amount RC. The characteristic curve thus displaced to the retard side is shown as the intake retard curve Inr.

  In this control mode, a negative overlap NOL is formed between EVC, which is the closing timing of the exhaust valve Vb, and IVO, which is the opening timing of the intake valve Va, and at the time of cranking (especially at the initial stage of cranking). ) Reduce the load acting on the crankshaft 1. Further, by reducing the pump loss at the exhaust valve Vb, the load acting on the crankshaft 1 is further reduced, and the crankshaft 1 can be speeded up.

(B) As described in the different embodiment (a), a negative overlap NOL is formed by the control of the intake side valve opening / closing timing control mechanism VTa and the control of the exhaust side valve opening / closing timing control mechanism VTb. Then, as shown in FIG. 10, it is also conceivable to control the EVC, which is the closing timing of the exhaust valve Vb, more retarded than the state shown in FIG. 9 so as to reduce the load caused by the negative overlap NOL.

  In the control of this other embodiment (b), it is easy to understand if it is assumed that the intake side valve opening / closing timing control mechanism VTa is hydraulic and includes a most retarded angle locking mechanism. Further, in the control of this another embodiment (b), as in the other embodiment (a), the advance operation amount AC (see FIG. 9) is obtained by the advance control of the EVO that is the opening timing of the exhaust valve Vb for each cylinder. The time during which the exhaust valve Vb is in the open state is controlled by retarding the EVC, which is the closing timing of the exhaust valve Vb, by the retard control amount RC (see FIG. 9) by the retard control. The control to extend is executed.

  Furthermore, in addition to the control mode in which the exhaust valve Vb opens and closes according to the exhaust extension curve Exe in which the EVO that is the opening timing is early and the EVC that is the closing timing is delayed as in this control, the entire exhaust extension curve Exe is retarded. By displacing the exhaust valve, the exhaust valve Vb is opened and closed according to the exhaust displacement curve EXer.

  By performing such control, the negative overlap NOL can be eliminated and the pumping loss due to the negative overlap NOL can be reduced.

(C) As described in another embodiment (b), the intake side valve opening / closing timing control mechanism VTa is configured so that the opening / closing timing can be set by hydraulic pressure.

  The present invention can be used in a control device for an internal combustion engine.

1 crankshaft 4 piston 15 starter motor E engine (internal combustion engine)
M Phase control motor (electric actuator)
Va intake valve Vb exhaust valve VT valve timing control mechanism

Claims (2)

A plurality of cylinders having a piston that reciprocates in a cylinder in conjunction with rotation of the crankshaft, an intake valve and an exhaust valve that opens and closes a combustion chamber in association with rotation of the crankshaft, and the crankshaft is driven to rotate An internal combustion engine comprising a starter motor and a valve opening / closing timing control mechanism for setting an opening / closing timing of the exhaust valve by driving an electric actuator;
When cranking is performed by the starter motor, EVO, which is the opening timing of the exhaust valve, is advanced and EVC, which is the closing timing of the exhaust valve, is delayed for those in the exhaust stroke among the plurality of cylinders. A control device for an internal combustion engine that controls the electric actuator so as to be squared. 2. The electric actuator is controlled based on a combustion speed in the combustion chamber after the first combustion of the cylinder, the order of which is set to be burned last among the plurality of cylinders, is performed. Control device for internal combustion engine.

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