JP2009209723A - Start control device and start control method of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress engine vibrations due to engine torque fluctuations after stopping an operation of compression pressure reducing means. <P>SOLUTION: After stopping the operation of compression pressure reducing means, a crank angle CA10 at which an initial expansion stroke starts is calculated (S103), and a motor torque 1 of a motor generator to be changed when the crank angle CA reaches the crank angle CA10, is calculated (S104). After that, it is determined whether an engine crank angle CA has reached the crank angle CA10 (S105), and when the crank angle CA has reached the crank angle CA10, the motor torque is reduced down to the motor torque 1 (S106). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine start control device and a start control method, and more particularly to an engine start control device including compression pressure reducing means for reducing compression pressure in a cylinder and suppressing engine vibration when the engine is started. And a start control method.

Japanese Patent Application Laid-Open No. 2004-133867 discloses a technique for driving an electric motor to rotate an engine and starting a decompression device until the engine rotational speed is higher than a resonance rotational speed of the engine to suppress engine vibration. Are listed. According to this technique, an increase in engine vibration due to resonance can be suppressed by reducing the compression pressure in the cylinder by the decompression device until the engine rotation speed exceeds the resonance rotation speed.
Japanese Patent Laid-Open No. 8-28313

  By the way, after the operation of the compression pressure reducing means such as the decompression device is stopped, the reduced compression pressure returns to the normal state, so that engine torque fluctuation occurs, and the engine is displaced around the crankshaft and vibrates due to this torque fluctuation. . In that case, the engine torque acts in the opposite direction to the cranking torque in the compression stroke, and the engine torque acts in the same direction as the cranking torque in the expansion stroke. For this reason, when the transition is made from the compression stroke to the expansion stroke, the engine is shaken back, so that the rotational displacement amount of the engine may increase and vibration may increase. In consideration of engine startability, it is desirable to set the operation stop rotational speed of the compression pressure reducing means close to the resonance rotational speed. However, the closer the operation stop rotational speed is to the resonance rotational speed, the more The influence of is great.

  In Patent Document 1 described above, no consideration is given to the increase in engine vibration after the operation of the compression pressure reducing means is stopped, and it cannot be said that the engine vibration at the time of starting the engine can be sufficiently suppressed.

  The present invention has been made paying attention to the above-mentioned problems, and provides an engine start control device and method for suppressing an increase in engine vibration at the time of engine start without impairing engine startability. With the goal.

  For this reason, the engine start control device of the present invention comprises a motor that cranks the engine at the time of starting, and a compression pressure reducing means that operates at the time of starting to reduce the compression pressure in the cylinder of the engine. In an engine that suppresses engine vibration by operating the compression pressure reducing means until the speed reaches an operation stop rotational speed higher than a low rotational speed range including a vibration resonance rotational speed, after the operation of the compression pressure reducing means is stopped. The motor output torque changing means for changing the output torque of the motor is provided.

  The engine start control method according to the present invention includes a motor for cranking the engine at the start, and a compression pressure reducing unit that operates at the start to reduce the compression pressure in the cylinder of the engine. When the engine that suppresses the vibration of the engine by operating the compression pressure reducing means until the operation stop rotational speed is higher than the low rotational speed range including the vibration resonance rotational speed, the operation of the compression pressure reducing means is performed. The output torque of the motor is changed after stopping.

  According to the present invention, after the operation of the compression pressure reducing means is stopped, the output torque of the motor is changed, thereby suppressing the engine swingback caused by the torque fluctuation after the operation of the compression pressure reducing means is stopped. Thereby, it is possible to suppress an increase in engine vibration after the operation of the compression pressure reducing unit is stopped.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of a power train of a one-motor hybrid vehicle to which the present invention is applied.

  In FIG. 1, the output shaft of the engine 1 is connected to a motor / generator 3 via a clutch 2, and the motor / generator 3 is connected to a transmission 5 via a clutch 4.

  The inverter 6 converts the DC power from the battery 7 into AC power and outputs it to the motor / generator 3 to drive the motor / generator 3 as a motor. Further, when the motor / generator 3 functions as a generator, the inverter 6 converts the generated power from the motor / generator 3 into DC power and charges the battery 7.

  The engine 1 is controlled by an engine controller (hereinafter referred to as ECM) 8, the motor / generator 3 is controlled by a motor controller (hereinafter referred to as MC) 9, and these ECM 8 and MC9 are hybrid controllers (hereinafter referred to as HCM). Are collectively controlled by a control signal from 10. The HCM 10 also outputs control signals to the clutches 2 and 4 and the inverter 6.

FIG. 2 is a system block diagram of the hybrid vehicle described above.
The HCM 10 outputs predetermined control signals to the ECM 8 and MC 9 based on signals input from various sensors.

  The signals input to the HCM 10 include an engine rotational speed signal NE from the rotational speed sensor 11, a rotational displacement amount RA around the crankshaft with respect to a stopped state of the main body of the engine 1 from the rotational displacement detection sensor 12 as rotational displacement amount detecting means, The state of charge SOC of the battery 7 from the battery sensor 13, the cooling water temperature signal TW from the water temperature sensor 14, the atmospheric temperature signal TA from the atmospheric temperature sensor 15, the atmospheric pressure signal PA from the atmospheric pressure sensor 16, and the crank angle sensor 17 For example, the crank angle signal CA. Alternatively, the engine speed may be detected by the crank angle sensor 17 with the rotation speed sensor 11 omitted. The rotational displacement amount RA about the crankshaft of the main body of the engine 1 may be calculated from the damper coefficient of the engine mount and the motor output torque (hereinafter referred to as motor torque). In this case, the HCM 10 has a function of a rotational displacement amount detection means, and the rotational displacement detection sensor 12 can be omitted.

  Control signals output from the HCM 10 include a target engine torque signal and compression pressure reduction permission / stop signal for the ECM 8, a control switching signal (torque control / rotational speed control) for the MC 9, a target torque signal, a target rotational speed signal, and the like. . Based on the compression pressure reduction permission / stop signal of the HCM 10, a compression pressure reduction means control signal is output from the ECM 8 to the compression pressure reduction means 18.

  The HCM 10 outputs a predetermined control signal to the ECM 8 and MC 9 when the engine is started, cranks the engine 1 by the motor generator 3, and generates a compression pressure reduction means control signal from the ECM 8 to generate the compression pressure reduction means 18. The vibration of the engine 1 is suppressed by operating the. Further, when the engine speed NE during cranking reaches a predetermined operation stop rotational speed higher than a low rotational speed range including the vibration resonance rotational speed of the engine 1 based on the resonance frequency of the engine mount or the like, a compression pressure reduction stop signal is generated. Thus, the operation of the compression pressure reducing means 18 is stopped. Further, after the operation of the compression pressure reducing means 18 is stopped, torque change control of the motor / generator 3 as will be described later is executed to suppress vibration of the engine 1. Accordingly, the HCM 10 has a function of a motor output torque changing unit.

FIG. 3 shows an example of the engine 1.
The engine 1 is a diesel engine, and intake air is drawn into a cylinder 27 from an air cleaner 21 via an intake valve 26 that is opened and closed by an intake passage 22, a collector 23, an intake manifold 24, and an intake cam 25.

  A piston 28 is inserted into the cylinder 27, and fuel is injected and supplied by a fuel injection valve 29. The combustion exhaust is discharged to an exhaust passage 32 through an exhaust valve 31 that is opened and closed by an exhaust cam 30.

A part of the exhaust gas is introduced into the EGR passage 33 as EGR gas, and is returned to the intake manifold 24 while the EGR amount is controlled by the EGR valve 34.
And as said compression pressure reduction means 18, at least 1 is provided among the following each means.

  The throttle valve 34 is constituted by a butterfly valve, for example, and reduces the cross-sectional area of the intake passage 22 for a predetermined period at the time of starting to lower the pressure (intake pressure) downstream of the valve, thereby reducing the compression pressure (FIG. 4A )reference).

  The intake shut-off valve 35 is constituted by a butterfly valve, a flap valve, a poppet valve, etc., and shuts off the intake passage continuously or in a predetermined section (intake stroke) in one cycle, lowers the pressure downstream of the valve, and reduces the compression pressure. To reduce. Preferably, the “closed” timing is adjusted so that the fluctuation in the cylinder pressure does not occur in one cycle (see FIG. 4B).

  The intake valve characteristic variable means (intake valve opening / closing timing variable means or intake valve operating angle variable means) 36 changes the valve center angle by changing the phase of the intake cam or uses a plurality of cams having different profiles. Using other known variable valve mechanisms such as switching, the compression pressure is reduced by changing (limiting) the amount of air flowing into the cylinder during the intake stroke. (See FIG. 4C). The continuously variable type has no step when changing the cylinder internal pressure, and the switching type has the advantage that the compression pressure can be changed quickly.

  When the decompression device 37 shown in FIG. 5 is operated (ON), the valve or intake valve 26 provided separately from the intake / exhaust valves 26 and 31 is opened to release the air in the cylinder 27 to the intake passage and compress the pressure. By opening the other valve or the intake valve 26 by a minute amount in the compression stroke, the air in the cylinder 27 is released to the intake passage also in the compression stroke.

  By the way, when the operation of the compression pressure reducing means 18 is stopped, the torque fluctuation occurs because the compression pressure of the engine 1 returns to the normal state. At this time, when the engine body 1 is rotationally displaced by the cranking torque, the engine body 1 is rotationally displaced in the opposite direction by the engine torque due to the compression stroke. Furthermore, since the directions of the engine torque and the cranking torque are the same in the expansion stroke, the main body of the engine 1 is rotationally displaced in the opposite direction to that in the compression stroke and is shaken back. There is a possibility that the vibration of the engine 1 may increase as the engine stop speed at which the compression pressure reducing means 18 is stopped is closer to the vibration resonance rotation speed, and the influence of the swing back on the engine vibration is greater. Therefore, in consideration of the startability of the engine 1, when the engine stop speed of the compression pressure reducing means 18 is set close to the vibration resonance speed, the rotational displacement of the engine due to the swing back is suppressed. is important.

  Therefore, in the present invention, after the operation of the compression pressure reducing means 18 is stopped, the output torque of the motor / generator 3 for cranking is changed to suppress the above-described swinging back, so that the vibration of the engine 1 is reduced. The increase is suppressed. Specifically, in consideration of the startability of the engine 1, during cranking, it is common to crank at the maximum motor torque that can be exhibited in the state of charge of the battery at that time. Decrease the motor torque to suppress the swing back.

Next, an embodiment of motor torque change control after the operation of the compression pressure reducing means 18 is stopped will be described.
FIG. 6 is a flowchart showing a first embodiment of torque change control of the motor / generator 3.

  When a request for starting the engine 1 is generated and the cranking of the engine 1 is started together with the start of the operation of the compression pressure reducing means 18, in step S101, the rotational displacement amount RA, the crank angle CA, and the engine rotational speed NE of the engine 1 are started. Read sensor information. Here, when the start request is generated, when the ignition key is turned “ON” from “OFF”, or when the target engine torque calculated by the HCM 10 is changed from “0” to “a value greater than 0”. Etc. The cranking is performed by outputting a torque control signal and a target torque from the HCM 10 to the MC 9, and driving and controlling the motor / generator 3 by the MC 9 so that the target torque is realized.

  In step S102, it is determined whether or not the read engine rotational speed NE is equal to or higher than NE-L. The NE-L is set higher than the low rotation range including the vibration resonance rotational speed of the engine 1 based on the resonance frequency range of the engine mount or drive system in which the engine 1 resonates. Is speed. Here, when it is determined that NE ≧ NE−L, the operation of the compression pressure reducing unit 18 is stopped, and the process proceeds to step S103.

  In step S103, based on the crank angle CA read in step S101, as shown in FIG. 7, after the operation of the compression pressure reducing means 18 is stopped, a crank angle CA10 at which the first expansion stroke starts is calculated.

  In step S104, the motor torque 1 of the motor / generator 3 to be changed when the crank angle CA10 is reached is calculated according to the rotational displacement amount RA1 of the engine 1. Here, the rotational displacement amount RA1 may be the rotational displacement amount RA11 immediately after the operation of the compression pressure reducing means 18 stops, or the rotational displacement amount RA12 when the crank angle CA10 is reached. When the rotational displacement amount RA1 is the rotational displacement amount RA11 immediately after the operation of the compression pressure reducing means 18 is stopped, the motor torque 1 is calculated with reference to a preset characteristic map of FIG. When the rotational displacement amount RA1 is the rotational displacement amount RA12 when the crank angle CA10 is reached, the motor torque 1 is calculated with reference to a preset characteristic map of FIG. From the characteristic maps of FIGS. 8 and 9, the motor torque 1 is decreased as the rotational displacement amount RA is increased.

  As the rotational displacement RA1, the rotational displacement RA13 estimated from the motor torque before the change may be used by using a preset characteristic map of FIG. In this case, when the motor torque immediately after the stop of the operation of the compression pressure reducing means 18 is selected as the motor torque before the change, the motor torque 1 may be calculated from the rotational displacement amount RA13 according to the characteristic map of FIG. Further, when the motor torque when the crank angle CA10 immediately before the torque change is selected as the motor torque before the change, the motor torque 1 may be calculated from the rotational displacement amount RA13 according to the characteristic map of FIG.

  In step S105, it is determined whether or not the engine crank angle CA has reached the crank angle CA10. If it is determined that the engine crank angle CA ≧ CA10, the process proceeds to step S106.

In step S106, the motor torque is changed to the motor torque 1 calculated in step S104.
According to this embodiment, as shown in FIG. 11, when the first expansion stroke starts after the operation of the compression pressure reducing means 18 stops, the motor torque (cranking torque) is changed to the motor torque 1 (A in the figure). ) Can be suppressed, and the rotational displacement amount RA of the engine 1 during the expansion stroke is reduced (A in the figure). Thereby, the increase in the vibration of the engine 1 after the operation of the compression pressure reducing means 18 is stopped can be effectively suppressed.

  In FIG. 11, A shows changes in various state quantities in the case of the present embodiment, and B shows changes in various state quantities in the case of the conventional example in which the motor torque is not changed after the operation of the compression pressure reducing means 18 is stopped. Show. The engine torque in the figure represents the torque of the entire engine.

FIG. 12 is a flowchart showing a second embodiment of torque change control of the motor / generator 3.
In the present embodiment, the motor torque is reduced during the first expansion stroke after the operation of the compression pressure reducing means 18 is stopped.

Steps S201 and S202 are the same as those in the first embodiment, and a description thereof will be omitted.
When the determination in step S202 is Yes and the process proceeds to step 203, the crank angle CA11 (preliminarily set during the first expansion stroke after the operation of the compression pressure reducing means 18 is stopped based on the crank angle CA read in step S201. 7) is calculated.

  In step S204, the motor torque 1 of the motor / generator 3 to be changed when the crank angle CA11 is reached is calculated. Also in this case, similarly to the first embodiment, the motor torque 1 is set according to the rotational displacement amount RA11 immediately after the operation of the compression pressure reducing means 18 is stopped or the rotational displacement amount RA12 when the crank angle CA10 or CA11 is reached. calculate. It should be noted that the characteristic map of FIG. 9 may be used when calculating the rotational displacement amount in the case of the crank angle CA11. Needless to say, the motor torque 1 may be calculated according to the rotational displacement RA13 estimated using the characteristic map of FIG.

  In step S205, it is determined whether or not the engine crank angle CA has reached the crank angle CA11. If the engine crank angle CA ≧ CA11 is reached, the motor torque is changed to the motor torque 1 calculated in step S204 in step S206. .

According to the present embodiment, as in the first embodiment, an increase in vibration of the engine 1 after the operation of the compression pressure reducing means 18 is stopped can be effectively suppressed.
During the expansion stroke, the engine rotational displacement amount RA1 is calculated at predetermined intervals, and the motor torque 1 is sequentially changed according to the rotational displacement amount RA11 at each calculation of the rotational displacement amount RA11. Good.

FIG. 13 is a flowchart showing a third embodiment of torque change control of the motor / generator 3.
In this embodiment, the motor torque is changed (increased) at the start of the second expansion stroke or at the end of the expansion stroke after the motor torque is changed (decreased) in the same manner as in the first embodiment. It is.

The operations from step S301 to S306 are the same as in the first embodiment, and a description thereof will be omitted.
In step S307, the crank angle CA2 is calculated based on the crank angle CA read in step S301. Here, as shown in FIG. 14, the crank angle CA2 is the crank angle CA20 at the start of the second expansion stroke or the crank angle CA21 at the end of the first expansion stroke after the operation of the compression pressure reducing means 18 is stopped. Of these, the angle from the crank angle CA10 is the smaller one. The crank angles CA20 and CA21 vary depending on the operating angle of the intake / exhaust cam and the number of cylinders.

In step S308, it is determined whether or not the engine crank angle CA has reached the crank angle CA2. If it is determined that the engine crank angle CA ≧ CA2, the process proceeds to step S309.
In step S309, the motor torque is changed to motor torque 2. Here, the motor torque 2 may be returned to the motor torque before the change, or may be calculated according to the engine rotation speed at the crank angle CA2 with reference to the characteristic map of FIG.

  According to this embodiment, as in the first embodiment, in addition to the effect of suppressing the vibration of the engine 1, at the end of the expansion stroke or the start of the second expansion stroke, as shown in FIG. By increasing the torque (cranking torque), it is possible to prevent a decrease in the rate of increase of the engine rotational speed NE and to obtain good engine startability. In FIG. 16, A shows changes in various state quantities in the case of this embodiment, and B shows changes in various state quantities in the case of the conventional example in which the motor torque is not changed after the operation of the compression pressure reducing means 18 is stopped. Yes.

FIG. 17 is a flowchart showing a fourth embodiment of torque change control of the motor / generator 3.
In this embodiment, when the fuel injection is started in the cylinder where the compression pressure first returns after the operation of the compression pressure reducing means 18 is stopped, the motor torque is changed according to the combustion generation torque at that time. is there.

In step S401, in addition to the rotational displacement amount RA of the engine 1, the crank angle CA, and the engine rotational speed NE, the fuel injection amount is read.
In step S402, it is determined whether or not the read engine rotational speed NE is equal to or higher than the operation stop rotational speed NE-L. If it is determined that NE ≧ NE-L, the process proceeds to step S403, and is read in step S401. A crank angle CA10 is calculated based on the crank angle CA.

In step S404, the combustion generation torque is calculated based on the fuel injection amount read in step S401.
In step S405, motor torque 1 is calculated based on the combustion generation torque calculated in step S404 and the rotational displacement amount RA1 calculated in the same manner as in the first embodiment. Here, the motor torque 1 at this time is calculated with reference to the characteristic map of FIG. As shown in FIG. 18, the greater the combustion generated torque, the greater the in-cylinder pressure due to the combustion pressure, so the motor torque 1 is reduced.

Subsequent operations in steps S406 to S410 are the same as those in the third embodiment, and a description thereof will be omitted.
According to this embodiment, as shown in FIG. 19, the motor torque is reduced by adding the motor torque decrease due to the combustion generation torque to the motor torque decrease in the first embodiment (A in FIG. 19). Since it decreases (A ′ in FIG. 19), vibration of the engine 1 can be suppressed even when fuel is injected. Further, thereafter, by increasing the motor torque, it is possible to prevent a decrease in the increase rate of the engine rotation speed NE, and to obtain a good engine startability.

  Note that, as shown by A ″ (indicated by a dotted line) in FIG. 19, the combustion generation torque change in the expansion stroke is estimated based on the fuel injection amount, and the motor torque 1 during the expansion stroke is estimated according to the estimated combustion generation torque change. There is also a motor torque change control in which the reduction amount is variably set and the motor torque return amount when the motor torque is returned at the end of the expansion stroke or at the start of the second expansion stroke is reduced in consideration of the engine torque due to combustion. Conceivable.

  In each of the above-described embodiments, an example in which cranking is performed with the maximum motor torque that can be exhibited by the motor / generator 3 in order to speed up the startup of the engine 1 has been described. For example, if the cranking torque is increased at the start of the first compression stroke after the operation of the compression pressure reducing means 18 is stopped, the rotational displacement RA drops due to the engine torque in the compression stroke. (See FIG. 11). Thereby, the engine can be prevented from swinging back.

  In the above description, an example in which the present invention is applied to a one-motor hybrid vehicle is shown, but the present invention is not limited to this. The present invention is also applicable to a two-motor hybrid vehicle shown in FIG. 20 and an engine vehicle equipped with an engine equipped with a starter motor 51 shown in FIG. In the two-motor hybrid vehicle shown in FIG. 20, for example, the first motor / generator 3a is used for driving a vehicle, the second motor / generator 3b is used for starting an engine, and the second motor / generator 3b and the engine 1 are connected. The engine 1 is cranked in conjunction with the belt 41. In FIG. 20, reference numerals 6b and 9b denote an inverter and a motor controller for the second motor / generator 3b.

The block diagram which shows an example of the power train of the hybrid vehicle of 1 motor system to which this invention is applied. The system block diagram of a hybrid vehicle same as the above. The schematic block diagram which shows an example of the engine of a hybrid vehicle same as the above. The figure which shows the effect | action for every different compression pressure reduction means in an engine same as the above. The schematic block diagram which shows an example of the engine provided with the decompression apparatus as a compression pressure reduction means. The flowchart which shows 1st Embodiment of the motor torque change control by this invention. Explanatory drawing regarding crank angle calculation at the time of motor torque reduction. The figure which shows the characteristic map which calculates reduction motor torque from engine rotation displacement amount. The figure which shows another characteristic map which calculates reduction motor torque from an engine rotational displacement amount. The figure which shows the characteristic map in the case of estimating a rotational displacement amount from the motor torque before a change. The comparison figure of the change of the various state quantity of 1st Embodiment and a prior art example. The flowchart which shows 2nd Embodiment of the motor torque change control by this invention. The flowchart which shows 3rd Embodiment of the motor torque change control by this invention. Explanatory drawing regarding crank angle calculation at the time of motor torque increase. The figure which shows the characteristic map which calculates increase motor torque from an engine speed. The comparison figure of the change of the various state quantity of 3rd Embodiment and a prior art example. The flowchart which shows 4th Embodiment of the motor torque change control by this invention. The figure which shows the characteristic map which calculates reduction motor torque from the engine rotational displacement amount at the time of combustion injection. The comparison figure of the change of the various state quantity of 4th Embodiment and a prior art example. 1 is a block diagram showing an example of a power train of a two-motor hybrid vehicle to which the present invention can be applied. The block diagram which shows an example of the power train of the engine vehicle which can apply this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 3 Motor generator 8 Engine controller 9 Motor controller 10 Hybrid controller 11 Rotational speed sensor 12 Rotation displacement detection sensor 17 Crank angle sensor 18 Compression pressure reduction means 34 Throttle valve 35 Intake shut-off valve 36 Intake valve characteristic variable means 37 Decompression device

Claims (9)

A motor that cranks the engine at the time of starting, and a compression pressure reducing means that operates at the time of starting to reduce the compression pressure in the cylinder of the engine, and the engine speed is in a low speed range including a vibration resonance speed In an engine that suppresses vibration of the engine by operating the compression pressure reducing means until a higher deactivation rotational speed is achieved,
An engine start control device comprising motor output torque changing means for changing the output torque of the motor after the operation of the compression pressure reducing means is stopped.   Rotational displacement amount detection means for detecting the rotational displacement amount around the crankshaft with respect to the stop state of the engine is further provided, and the motor output torque is changed according to the rotational displacement amount detected by the rotational displacement amount detection means. The engine start control device according to claim 1, wherein   The engine start control device according to claim 2, wherein the motor output torque is decreased as the rotational displacement amount is increased.   The engine start control device according to any one of claims 1 to 3, wherein the change period of the motor output torque includes at least an initial expansion stroke after the operation of the compression pressure reducing unit is stopped.   The completion timing of the change of the motor output torque is set to the earlier one of the end time of the first expansion stroke and the start time of the second expansion stroke after the operation of the compression pressure reducing means is stopped. Item 5. The engine start control device according to any one of Items 1 to 4.   The engine start control device according to any one of claims 1 to 5, wherein the motor output torque is changed in accordance with a generated torque of the engine.   The engine start control device according to claim 6, wherein the generated torque of the engine is estimated based on a fuel injection amount.   8. The engine start control device according to claim 7, wherein the motor output torque is reduced as the fuel injection amount increases. A motor that cranks the engine at the time of starting, and a compression pressure reducing means that operates at the time of starting to reduce the compression pressure in the cylinder of the engine, and the engine speed is in a low speed range including a vibration resonance speed When starting the engine to suppress the vibration of the engine by operating the compression pressure reducing means until a higher deactivation rotational speed,
An engine start control method, wherein the output torque of the motor is changed after the operation of the compression pressure reducing means is stopped.

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