Vehicle

Abstract

A vehicle wherein: when an ignition off operation for issuing a command to stop an engine (1) is performed while in a state in which the opening / closing timing has been made to deviate from the initial position by a variable valve timing mechanism (30), return control for returning the opening / closing timing to the initial position is performed, and when surrounding atmospheric pressure information satisfies prescribed requirements, delay control for delaying the stopping of the engine (1) after the ignition off operation is performed by a prescribed period; and after the ignition off operation, the transition speed of the opening / closing timing to the initial position when subjected to the delay control is set so as to be lower than the transition speed of the opening / closing timing to the initial position when not subjected to the delay control.

Description

Vehicle

[0001] This invention relates to a vehicle equipped with an internal combustion engine.

[0002] Conventionally, an internal combustion engine (hereinafter referred to as an engine) equipped with a variable valve timing mechanism has been widely used. The variable valve timing mechanism changes the crank angle, which is the phase at which the intake valve and the exhaust valve open and close, according to the operating state. Its structure generally changes the phase by relatively rotating the camshaft that drives the intake valve and the exhaust valve to open and close with respect to a sprocket or the like to which the rotation of the crankshaft is transmitted. The relative rotation of the camshaft is performed by various actuators composed of a hydraulic mechanism or an electric motor.

[0003] In an engine equipped with a variable valve timing mechanism (Variable Valve Timing / VVT mechanism), it is desirable to return the camshaft to the initial position (usually the neutral position) in preparation for the next engine start and then stop the engine when the ignition is off. For this reason, after the ignition off operation, ignition off delay control (hereinafter referred to as delay control) that delays the stop of the engine for a predetermined time is performed.

[0004] By the delay control, since the engine continues to operate even after the ignition off operation, the camshaft can be returned to a predetermined position. Furthermore, a time margin is ensured for the pin of the lock mechanism that restricts the rotation of the camshaft to reliably fit into the locking portion of the camshaft (see, for example, Patent Documents 1 and 2).

[0005] Japanese Unexamined Patent Application Publication No. 2015-194135, Japanese Unexamined Patent Application Publication No. 2007-327472

[0006] However, in highlands where the environment is under low pressure, in order for the engine to operate at the same output as on flat ground, it is necessary to increase the intake air volume (volume flow rate) compared to the case of flat ground. In such a low pressure environment, a situation is assumed where an ignition off operation is performed with the VVT greatly advanced for the purpose of maintaining the idle rotation.

[0007] In this case, the delay control allows the engine to continue running even after the ignition is turned off, but because the VVT ​​is returned to its initial position (retarding the VVT ​​timing), it may become impossible to secure enough intake air to maintain idle speed in a low-pressure environment. If sufficient intake air is not secured, the engine will suffer from a lack of torque, which can lead to a deterioration in engine feel.

[0008] Therefore, the objective of this invention is to stabilize engine operation when performing delay control in a low-pressure environment.

[0009] To solve the above problems, this invention provides a vehicle comprising an engine equipped with an intake valve and an exhaust valve, a variable valve timing mechanism that changes the opening and closing timing of at least one of the intake valve and the exhaust valve, and a control unit that controls the engine and the variable valve timing mechanism, wherein when an ignition off operation is performed to command the engine to stop when the opening and closing timing is set by the variable valve timing mechanism by a predetermined amount or more from the initial position corresponding to the start of the engine, the control unit performs a return control to return the opening and closing timing to the initial position and a delay control to delay the stopping of the engine after the ignition off operation by a predetermined time, and sets the speed at which the opening and closing timing moves to the initial position in the delay control after the ignition off operation to be lower than the speed at which the opening and closing timing moves to the initial position in the case without the delay control (Configuration 1).

[0010] In configuration 1, the system is equipped with an environmental information acquisition means for acquiring ambient atmospheric pressure, and the control unit can adopt a configuration that advances the opening and closing timing of the intake valve from its initial position as the atmospheric pressure decreases (configuration 2).

[0011] In configuration 1 or 2, the control unit can adopt a configuration in which the movement speed is set lower the longer the predetermined time (configuration 3).

[0012] In any one of configurations 1 to 3, a configuration can be adopted in which, during the delay control, control is performed to reduce the torque of the engine supplied to peripheral equipment driven by the engine (configuration 4).

[0013] In configuration 4, the peripheral equipment is an auxiliary device driven by the rotation of the crankshaft of the engine, and the control unit can adopt a configuration that stops the driving of the auxiliary device during the delay control (configuration 5).

[0014] Furthermore, in configuration 4, the peripheral equipment is a transmission connected to the crankshaft of the engine via a clutch, and the control unit can adopt a configuration that disengages the clutch during the delay control (configuration 6).

[0015] In any one of configurations 1 to 6, the control unit may adopt a configuration in which it does not perform the delay control even if the opening and closing timing is more than a predetermined amount away from the initial position, if the engine speed is above a predetermined speed (configuration 7).

[0016] In any one of configurations 1 to 7, the control unit may adopt a configuration that increases or decreases the predetermined time according to the temperature of the lubricating oil contained inside the engine (configuration 8).

[0017] According to this invention, engine operation can be stabilized when performing delay control in a low-pressure environment.

[0018] This is a schematic diagram showing the control device for the vehicle and engine of this invention. This is a graph showing the opening and closing timing of the intake valve and exhaust valve. This is a graph showing the control of this invention. This is a graph showing the control of this invention. This is a graph schematically showing the engine speed fluctuations during the control of Figures 3A and 3B.

[0019] Embodiments of this invention will be described based on the drawings. Figure 1 shows an engine 1 and its control device, as well as components surrounding the engine 1, mounted on a vehicle 60 according to an embodiment of this invention. Note that only components directly related to this invention are shown in the figure, and descriptions of other general components are omitted.

[0020] As shown in Figure 1, the engine 1 includes a combustion chamber 3, which is a space enclosed by the lower surface of the cylinder head 7, the inner surface of the cylinder bore formed in the cylinder block 2, and the top surface of the piston 4. The piston 4 reciprocates in response to the combustion of the air-fuel mixture supplied into the combustion chamber 3, and this reciprocating motion rotates the crankshaft 5. Note that the figure shows the main part of one of the multiple cylinders of the engine 1, and this invention can be applied regardless of the number of cylinders.

[0021] The engine 1 also includes an intake passage 11 that sends intake air into the combustion chamber 3, an exhaust passage 12 drawn out from the combustion chamber 3, and a fuel injection device 40 for injecting fuel. The openings 11a and 12a of the intake passage 11 and the exhaust passage 12 to the combustion chamber 3 are opened and closed by an intake valve 21 and an exhaust valve 22, respectively. In this embodiment, the fuel injection device 40 includes a port injection valve 42 that injects fuel into the intake port 11b, which is the connection part of the intake passage 11 to the combustion chamber 3, and a direct injection valve 41 that injects fuel directly into the combustion chamber 3. However, the fuel injection device 40 may also consist of only one of the port injection valve 42 and the direct injection valve 41.

[0022] The intake passage 11 is provided with a throttle valve 13, an air cleaner 15, and the like, which adjust the flow area of ​​the intake passage 11, extending upstream from the intake port 11b. The exhaust passage 12 extends downstream from the exhaust port 12b, which is the connection point to the combustion chamber 3, and is open to the atmosphere at its end.

[0023] The intake passage 11 is equipped with a sensor device that acquires information necessary for controlling the engine 1, such as an airflow sensor 14 that detects the amount of air flowing through the intake passage 11. Furthermore, the engine 1 is equipped with a rotational speed sensor that detects the rotational speed of the crankshaft 5. Sensors and components that are not labeled with reference numerals are not shown (the same applies in the following paragraphs).

[0024] Vehicle 60 is equipped with an accelerator pedal and a brake pedal. The accelerator pedal is equipped with an accelerator position sensor that detects the amount the driver presses the accelerator. In addition, the brake device 9, which is located near the wheel 8, is activated by the operation of the brake pedal. Furthermore, vehicle 60 is equipped with a pressure sensor 61 that acquires information on the ambient pressure. The electronic control unit 50 can acquire information from these various sensors via cables. In Figure 1, some of the cables are omitted from the illustration.

[0025] The vehicle 60 is equipped with an electronic control unit 50 for controlling the engine 1. Based on information from the airflow sensor 14, rotational speed sensor, accelerator position sensor, barometric pressure sensor 61, and other sensors, the electronic control unit 50 controls fuel injection by the fuel injector 40, controls the ignition timing of the ignition device 6, controls the opening degree of the throttle valve 13, and issues other commands necessary for controlling the engine 1.

[0026] The electronic control unit 50 is a collection of electronic control devices (computers) equipped with interfaces, processors, memory, etc., that are connected to each other via a bus. The electronic control unit 50 mainly includes a control unit 51 that controls the engine 1 and a vehicle control unit 52 that controls the operation of the entire vehicle 60. The electronic control unit 50 also includes an environmental information acquisition means 53.

[0027] The environmental information acquisition means 53 processes the information from the pressure sensor 61 to acquire pressure information (atmospheric pressure information) around the vehicle 60. Here, instead of the pressure sensor 61, altitude information (altitude above sea level) of the location where the vehicle 60 is located may be acquired using a GPS device and map function, and pressure information may be acquired from that altitude information. In other words, the means for acquiring pressure information may be other methods other than those exemplified.

[0028] Furthermore, the engine 1 is equipped with a variable valve timing mechanism (VVT mechanism) 30 that changes the opening and closing timing of the intake valve 21 and the exhaust valve 22. The variable valve timing mechanism 30 is controlled by a control unit 51.

[0029] The intake valve 21 and exhaust valve 22 are opened and closed by an intake camshaft 23 and an exhaust camshaft 24, which are arranged in parallel within the cylinder head 7. The intake camshaft 23 and the exhaust camshaft 24 are each provided with cams 23a and 24a, which have a non-circular cross-section. As the intake camshaft 23 and the exhaust camshaft 24 rotate around their axes, the cams 23a and 24a rotate in the same direction and press against the rear ends of the intake valve 21 and the exhaust valve 22, causing the intake valve 21 and the exhaust valve 22 to advance in the opening direction (towards the combustion chamber 3). As the pressing force weakens, the intake valve 21 and the exhaust valve 22 retract in the closing direction due to the biasing force of the valve springs.

[0030] The variable valve timing mechanism 30 changes the opening and closing timing of the intake valve 21 and exhaust valve 22 by moving the phase of the cam 23a on the intake camshaft 23 and the cam 24a on the exhaust camshaft 24 in the axial direction toward either the advance or retard side, respectively. In this embodiment, the adjustment is performed by continuously changing the phase of the intake and exhaust cams 23a and 24a, respectively, by the operation of hydraulic actuators 31 and 32.

[0031] Various known types of variable valve timing mechanisms 30 can be used. For example, a variable valve timing mechanism 30 can be configured to include a housing and a vane rotatably mounted relative to the housing on both the intake and exhaust sides. The intake and exhaust housings are rotated by an endless member (timing belt, timing chain, etc.), and the intake camshaft 23 and exhaust camshaft 24 are fixed to the intake and exhaust vanes, respectively (details of the variable valve timing mechanism 30 are not shown). By rotating the vanes relative to the housings through the action of hydraulic actuators 31 and 32, the opening and closing timing of the intake valve 21 and exhaust valve 22, respectively, is changed, that is, the phase of the intake camshaft 23 and exhaust camshaft 24 with respect to the crankshaft 5 (the timing at which the cam lobes face a predetermined direction). A mechanism using electric actuators may be used instead of hydraulic actuators 31 and 32.

[0032] Furthermore, the variable valve timing mechanism 30 is equipped with a locking mechanism that restricts movement from the initial position of the opening and closing timing. As a locking mechanism, for example, a mechanism is provided in which the rotation of the variable valve timing mechanism 30 (movement of the vane relative to the housing) is restricted by inserting reciprocable locking pins 25, 26 (see Figure 1) provided in the housing into engagement holes provided in the vane. The initial position is usually set to a neutral position in which the opening 11a of the intake port 11b and the opening 12a of the exhaust port 12b are fully closed when the piston 4 is at top dead center and bottom dead center. In addition, other known mechanisms may be used as this type of locking mechanism.

[0033] The variable valve timing mechanism 30 allows for the modification of the intake opening time (when the intake valve 21 is open), the intake closing time (when the intake valve 21 is closed), the exhaust opening time (when the exhaust valve 22 is open), and the exhaust closing time (when the exhaust valve 22 is closed). Therefore, it is possible to increase or decrease the valve overlap amount defined by the period from the intake opening time to the exhaust closing time, that is, the valve overlap period a shown in Figure 2, during which the intake valve 21 and exhaust valve 22 are open simultaneously. In Figure 2, the symbol e indicates the change in the lift amount (open / closed state) of the exhaust valve 22 in the neutral position, and the symbol d indicates the change in the lift amount (open / closed state) of the intake valve 21 in the neutral position. In Figure 2, the upper side of the vertical axis (the side with a larger lift amount) represents the open valve state, and the lower side represents the closed valve state.

[0034] Typically, in a four-stroke engine, the intake valve 21 is opened at a predetermined time near the end of the exhaust stroke to set valve overlap and improve the efficiency of intake air filling. For example, when operating the engine 1 at low to medium speeds under medium to high load, the intake valve 21 is advanced, i.e., opened and closed earlier, as shown by arrow b in Figure 2, to increase the overlap amount. In Figure 2, the symbol d' indicates the change in the lift amount (open / closed state) of the intake valve 21 after the advance. The symbol f indicates the intake opening timing of the intake valve 21 at the neutral position, i.e., the initial position set in response to the start of the engine 1 (equal to the exhaust closing timing of the exhaust valve 22 at the neutral position), and the symbol g indicates the intake opening timing of the intake valve 21 after the advance. Conversely, in the high-speed range, the intake valve 21 can be retarded, i.e., opened and closed later, in the direction of arrow c in Figure 2, to reduce the overlap amount. As in this example, the intake opening timing, intake closing timing, exhaust opening timing, and exhaust closing timing are controlled appropriately according to the operating conditions.

[0035] However, when the vehicle 60 is located at high altitude where atmospheric pressure is low, the air density decreases, so the required amount of intake air cannot be obtained with the same settings as on flat ground, resulting in the problem that the desired output cannot be obtained. For this reason, the control unit 51 sets the intake air volume as usual in a standard pressure environment where the atmospheric pressure information is above a predetermined value (or in a low-altitude environment where the elevation (altitude above sea level) is below a predetermined altitude), and controls the intake air volume to increase it compared to normal in a low-pressure environment where the atmospheric pressure information is below a predetermined value. This control that increases the intake air volume compared to normal in a low-pressure environment will be referred to as high-altitude control below.

[0036] High-altitude control is performed by control of a variable valve timing mechanism 30, etc. Below, we assume, for example, control to advance the timing of the intake valve 21. In this case, the intake opening timing and intake closing timing, which are the opening and closing timings of the intake valve 21, are both moved away from their initial positions toward the advanced timing side.

[0037] In this state, suppose an ignition-off operation is performed to command the engine 1 to stop. The control unit 51 performs a return control to return the opening and closing timing of the intake valve 21 to its initial position. Furthermore, if the opening and closing timing is more than a predetermined amount away from the initial position, in response to the return control, a delay control is performed to delay the stopping of the engine 1 after the ignition-off operation by a predetermined time. By continuing to operate the engine 1 even after the ignition-off operation, the return control can be reliably completed. In other words, the opening and closing timing returns to the initial position, and the lock mechanism that restricts movement from the initial position thereafter can be reliably operated.

[0038] Furthermore, if the opening and closing timing of the exhaust valve 22 is deviated from its initial position when the ignition is turned off, the exhaust valve 22 is also subjected to return control, and a corresponding delay control is performed. In addition, return control is performed without delay control even in operating conditions other than high-altitude control if the opening and closing timing of the intake valve 21 or exhaust valve 22 is deviated from its initial position. However, in the case of high-altitude control, the amount of deviation (angle) from the initial position is larger than in the normal case, so the importance of performing delay control is particularly high.

[0039] Incidentally, although the delay control allows engine 1 to continue operating even after the ignition is turned off, the amount of intake air gradually decreases as the opening and closing timing returns to the initial position. As a result, a torque shortage occurs before the recovery control is completed, making it impossible to maintain a stable idle speed, which leads to a deterioration in the feeling for the driver.

[0040] Therefore, in this invention, in the return control with delay control, the speed of movement to the initial position of the opening and closing timing is set lower than the speed of movement to the initial position of the opening and closing timing in the case without delay control. This suppresses the rapid increase or decrease in the rotational speed of the engine 1 due to a sudden change in the amount of intake air during the return control, and also suppresses the generation of unpleasant noise from the engine 1. At this time, it is desirable that the return control be completed during the delay control. That is, it is desirable that the time for which the delay control is continued is greater than or equal to the time required to complete the movement from the current opening and closing timing to the initial position of the opening and closing timing at the set speed during the return control. Here, the speed of movement to the initial position is the rotation angle (rotational angular velocity) of the camshafts 23, 24 or cams 23a, 24a per unit time.

[0041] In delay control, the predetermined time from the ignition-off operation until the engine 1 is stopped (hereinafter referred to as the delay duration) is determined according to the operating conditions and the surrounding environment. In this embodiment, a method is employed to adjust the delay duration according to atmospheric pressure information. Specifically, a method is employed in which the delay duration is set to be longer as the atmospheric pressure decreases.

[0042] Figure 3A shows the conventional delay control. Here, the symbol O in Figure 3A indicates the start period of the return control, and the symbol P0 indicates the end period of the return control. Also, the symbol θ0 indicates the phase (angle) of the initial position, and the symbol θ1 indicates the amount of phase shift (angle) to the advanced angle side from the initial position. Further, the symbol Z indicates a signal by which the control unit 51 instructs a change in the opening / closing timing, and at the start period O, it instructs a change from point α to point β. The symbol Y indicates the change in the phase of the opening / closing timing, and the actual change in the phase during the return control corresponds to the portion indicated by the symbol Y0. In this control, the rotation of the engine 1 is maintained until the symbol P0, and the engine 1 is stopped after the symbol P0.

[0043] The symbol X0 in Figure 3B indicates the fluctuation in the rotational speed of the engine 1 corresponding to the control of Figure 3A. In the behavior indicated by the symbol X0, since the amount of advanced angle decreases as the return control progresses, the rotational speed of the engine 1 is somewhat unstable.

[0044] Figure 3C shows the return control with delay control in the present embodiment. In Figure 3C, when the delay duration determined based on the atmospheric pressure information is set to a value te (for example, 5 seconds) corresponding to the atmospheric pressure information (for example, 800 hPa) at a certain high altitude, the operation time of the return control is set to time t1 (for example, 4 seconds). Here, although the lock mechanism operation time, which is the time from the start of the operation of the lock mechanism to the completion of the lock, is omitted from the illustration because it is very short, the lock mechanism operation time is also included in this return control operation time t1. For this reason, the lock by the lock mechanism is completed within the delay duration. Here, when the delay duration corresponding to the atmospheric pressure information (for example, 1000 hPa) in the standard pressure environment where no delay control is performed, that is, on flat ground, is set to t0 (see Figure 3A), t0 < t1 < te.

[0045] Thus, when delay control is involved, compared with the case where no delay control is involved, the operation time until the initial position in the return control is lengthened, and the moving speed of the opening / closing timing is decreased. Thereby, the operation of the engine 1 during the return control can be stabilized. Here, in Figure 3C, the symbol O also indicates the start period of the return control, the symbol P1 indicates the end period of the return control, and the symbol Pe indicates the end period of the delay control.

[0046] However, during the delay control, it is desirable to set the moving speed of the opening / closing timing lower as the set delay duration is longer. That is, in the example of FIG. 3C, although t1 < te, it is desirable to make the time t1 used for the return control as long as possible with t1 = te as the upper limit.

[0047] Incidentally, in the return control in a low-pressure environment with delay control, depending on the operating conditions, the intake air amount may be less than the amount of air required to maintain the idle rotation. In such a case, during the delay control, by performing control to reduce the torque of the engine 1 supplied to the peripheral devices driven by the engine 1, it is possible to avoid the engine 1 from becoming unstable in rotation. In this case, it is advisable to select a peripheral device that reduces the torque so that the rotation of the engine 1 does not increase rapidly.

[0048] For example, an accessory 62 (see FIG. 1) driven by the engine 1 can be cited as a peripheral device. A method in which the control unit 51 stops the drive of the accessory 62 during the delay control can be cited. The stop of the drive of the accessory 62 can be performed by disengaging a clutch disposed between the crankshaft 5 and the accessory 62. Examples of the accessory 62 include an alternator that generates electricity by the rotation of the crankshaft 5, a compressor of an air conditioner, and the like.

[0049] Also, for example, a transmission 65 can be cited as a peripheral device. The control unit 51 stops the transmission of the driving force from the crankshaft 5 to the transmission 65 and the wheel 8 (both see FIG. 1) by disconnecting the clutch 64 during the delay control, thereby reducing the torque.

[0050] Further, a fuel pump 66 and a negative pressure pump 63 can also be considered as peripheral devices. When the fuel injection device 40 includes a direct injection valve 41, the control unit 51 can use a method of stopping the operation of a fuel pump (high-pressure pump) 66 that supplies fuel to the direct injection valve 41 during the delay control, or a method of stopping the operation of a negative pressure pump 63 (both see FIG. 1) that operates the brake booster of the brake device (friction brake device) 9 under the condition that the vehicle 60 is operating the parking brake and is stopped.

[0051] Incidentally, if the vehicle 60 is a hybrid vehicle equipped with an engine 1 and a motor as a drive source for driving, the control unit 51 may choose not to perform delay control even in a low-pressure environment where the atmospheric pressure information is below a predetermined value, if the rotational speed of the engine 1 is above a predetermined rotational speed (for example, 2000 rpm or more). This is because, if the rotational speed of the engine 1 is high, even if the operation of the engine 1 is stopped immediately after the ignition is turned off, the recovery control can be completed before the rotational speed of the engine 1 becomes zero.

[0052] Furthermore, if the variable valve timing mechanism 30 is hydraulic, the delay duration determined above may be increased or decreased according to the temperature of the lubricating oil contained inside the engine 1. The temperature of the lubricating oil can be obtained by a temperature sensor installed in the oil pan of the engine 1 or elsewhere. For example, a method can be used in which the delay duration is shortened when the temperature of the lubricating oil is high because the flow of the lubricating oil is smoother (because the viscosity of the lubricating oil is low), and in which the delay duration is lengthened when the temperature of the lubricating oil is low because it takes time for the lubricating oil to flow (because the viscosity of the lubricating oil is high).

[0053] In the above embodiment, the variable valve timing mechanism 30 makes both the phase of the cam 23a on the intake side camshaft 23 and the phase of the cam 24a on the exhaust side camshaft 24 variable. However, this invention can also be applied if only the phase of either the intake side or the exhaust side is made variable.

[0054] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. Accordingly, the scope of the invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope of the claims are intended to be included.

[0055] 1 Engine 5 Crankshaft 21 Intake valve 22 Exhaust valve 30 Variable valve timing mechanism 40 Fuel injection system 50 Electronic control unit 51 Control unit 53 Environmental information acquisition means 60 Vehicle 62 Auxiliary equipment 64 Clutch

Claims

1. A vehicle comprising: an engine equipped with an intake valve and an exhaust valve; a variable valve timing mechanism for changing the opening and closing timing of at least one of the intake valve and the exhaust valve; and a control unit for controlling the engine and the variable valve timing mechanism, wherein when an ignition-off operation is performed to command the engine to stop while the opening and closing timing is deviated by a predetermined amount or more from the initial position set by the variable valve timing mechanism in correspondence with the engine startup, the control unit performs a return control to return the opening and closing timing to the initial position and a delay control to delay the engine stop after the ignition-off operation for a predetermined time, and sets the speed at which the opening and closing timing moves to the initial position in the delay control after the ignition-off operation to a lower speed at which the opening and closing timing moves to the initial position in the case without the delay control.

2. The vehicle according to claim 1, comprising an environmental information acquisition means for acquiring ambient pressure, wherein the control unit advances the opening and closing timing of the intake valve from the initial position as the atmospheric pressure decreases.

3. The vehicle according to claim 1 or 2, wherein the control unit sets the travel speed lower the longer the predetermined time is.

4. The vehicle according to any one of claims 1 to 3, wherein during the delay control, control is performed to reduce the torque of the engine supplied to peripheral equipment driven by the engine.

5. The vehicle according to claim 4, wherein the peripheral equipment is an auxiliary device driven by the rotation of the crankshaft of the engine, and the control unit stops driving the auxiliary device during the delay control.

6. The vehicle according to claim 4, wherein the peripheral equipment is a transmission connected to the crankshaft of the engine via a clutch, and the control unit disengages the clutch during the delay control.

7. The vehicle according to any one of claims 1 to 6, wherein the control unit does not perform the delay control if the engine speed is above a predetermined speed, even if the opening and closing timing is more than a predetermined amount away from the initial position.

8. The vehicle according to any one of claims 1 to 7, wherein the control unit increases or decreases the predetermined time according to the temperature of the lubricating oil contained inside the engine.

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