JP4171948B2 - Vehicle power unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle power device used in a vehicle equipped with an engine (internal combustion engine), and preferably relates to vibration suppression of a vehicle equipped with an idling stop system that frequently starts and stops the internal combustion engine.
[0002]
[Prior art]
In recent years, reducing fuel consumption of vehicles has become a major issue from the viewpoint of preventing global warming and air pollution. For this reason, the engine is stopped while the vehicle is stopped at an intersection or the like, and is restarted when starting. An idling stop system has been proposed.
[0003]
In this idling stop system, the engine is frequently stopped and started. Therefore, it is required to control the engine speed so as to avoid the resonance point of the vehicle body as much as possible while enhancing the durability of the engine starter.
In particular, from the standpoint of starting the engine longer than the engine stop and smoothly starting at the intersection, when the idling stop system is installed, the output of the starter motor is strengthened to increase the engine speed. We are trying to start up.
[0004]
[Problems to be solved by the invention]
However, since the engine speed always passes through the resonance point when the engine is stopped, the resonance vibration of the vehicle body that occurs in the vicinity of the resonance point every time the engine is stopped is particularly noticeable in a vehicle that employs an idling stop system. There has been a problem of significantly damaging the performance.
[0005]
The present invention has been made in view of the above problems, and an object to be solved is to provide a vehicle power unit that can reduce the resonance vibration of the vehicle body when the engine is stopped with a simple configuration.
[0012]
[Means for Solving the Problems]
According to the configuration of 請 Motomeko 1, wherein at least one of the rectifying elements or the upper arm side of the rectifier elements of the lower arm side of the full-wave rectifying circuit rectifies the generated power of the alternator that is driven to power the battery by the engine In addition, the switching elements are connected in parallel.
The plurality of switching elements are made conductive by a signal related to an engine stop command, whereby the armature coil of the AC machine is short-circuited. This short-circuiting is continued at least until the engine speed drops below the resonance speed value corresponding to the engine resonance point.
[0013]
In this way, by dissipating the inertia energy of the engine with a resistance loss such as an armature coil, the engine speed can quickly pass the resonance speed value and its vicinity when the engine is stopped. The unpleasant vehicle resonance phenomenon at the time of a stop can be reduced.
According to the configuration of claim 2, in the vehicular power unit according to claim 1 , the armature coil short-circuit switching element further converts DC power fed from the battery into AC power for driving an AC machine. Also serves as part of the inverter circuit.
[0014]
In this way, the engine is driven from the alternator as necessary, and known engine starting, engine damping control (torque fluctuation reduction control) and torque assist are performed while suppressing the complexity of the circuit configuration. Can do.
According to the configuration of the third aspect , the AC machine is connected to the battery through the bidirectional AC-DC converter so as to be able to exchange power, and as a result, exchanges torque with the engine.
[0015]
The bi-directional AC-DC converter is driven by a signal related to the engine stop command, and a multi-phase AC voltage is applied to the AC machine so that torque is generated in the direction opposite to the rotation direction, thereby forming a rotating magnetic field. This voltage application is continued at least until the rotational speed of the engine falls below the resonance rotational value corresponding to the resonance point of the engine.
In this way, due to the power generation effect of the resulting bidirectional AC-DC converter, the inertial energy of the engine when the engine is stopped is recovered by the battery, and the engine speed quickly reaches the resonance speed value and its vicinity. Since it can pass, the unpleasant vehicle resonance phenomenon at the time of an engine stop can be reduced.
[0016]
Furthermore, according to this configuration, it is possible to perform known engine starting, engine damping control (torque fluctuation reduction control), and torque assist without complicating the circuit configuration without complicating the circuit configuration. .
According to the configuration of the fourth aspect of the invention, in the vehicle power device according to any one of the first to third aspects, the engine rotational speed is lower than a rotational numerical value at the time of input of the engine stop command and corresponds to a vehicle resonance point. The switch or switching element is turned on or reversely driven when the engine speed is higher than the resonance speed value by a predetermined value or more, or when a predetermined first delay time is delayed from the signal input related to the engine stop command. The first delay time is set so that the engine speed at the time point delayed by one delay time is higher than the resonance speed value.
[0017]
In other words, in the present configuration, in view of the fact that the vehicle resonance phenomenon that occurs when the engine is stopped, which is the subject of the present invention, is generated when vibration energy due to engine torque fluctuation is transmitted to the vehicle when the engine speed is close to the resonance speed value. Absorption of the inertia energy of the engine by the machine is delayed not within the time immediately after the engine stop command is input but within a range where the engine speed is higher than the vicinity of the resonance speed value. Preferably, the inertia energy of the engine is absorbed by the AC machine from an engine speed range that is about 10 to 30% higher than the resonance speed value.
[0018]
In this way, it is possible to reduce the vehicle resonance phenomenon while suppressing the burden such as heat generation on the AC machine or the like. Therefore, this configuration is particularly effective when absorbing inertia energy by resistance loss due to short circuit of the armature coil of the AC machine.
According to the configuration of claim 5, in the vehicular power unit according to any one of claims 1 to 4 , the engine rotation speed is a rotation speed value that is lower than a predetermined resonance speed value by a predetermined value or more than a predetermined resonance speed value corresponding to the vehicle resonance point, Alternatively, the switch or the switching element is shut off or the reverse direction driving is terminated when a predetermined second delay time is delayed from the signal input related to the engine stop command, and the engine of the engine at the time when the second delay time is delayed. The second delay time is set so that the rotation speed is lower than the resonance rotation value.
[0019]
In other words, in the present configuration, in view of the fact that the vehicle resonance phenomenon that occurs when the engine is stopped, which is the subject of the present invention, is generated when vibration energy due to engine torque fluctuation is transmitted to the vehicle when the engine speed is close to the resonance speed value. Rather than absorbing the inertia energy of the engine by the machine until the engine is completely stopped, the engine speed is delayed within a range lower than the vicinity of the resonance speed value. Preferably, the absorption of the inertia energy of the engine by the alternator is terminated in an engine speed range lower by about 10 to 30% of the resonance speed value.
[0020]
In this way, it is possible to reduce the vehicle resonance phenomenon while suppressing the burden such as heat generation on the AC machine or the like. Therefore, this configuration is particularly effective when absorbing inertia energy by resistance loss due to short circuit of the armature coil of the AC machine. Further, the engine can be protected from the reverse drive, and the engine is not damaged.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
In addition to alternators dedicated to power generation and starter generators (starter generators), AC motors include generator motors with a torque assist function, generator motors with a vibration control function that generates torque in the opposite phase to engine torque fluctuations, etc. Further, the present invention can be applied to a rotating electrical machine that converts engine torque into electric power in a hybrid vehicle.
[0023]
The full-wave rectifier circuit may have a so-called bidirectional AC-DC converter configuration in which a bridge circuit is configured by connecting a diode and a switching element in parallel in addition to a normal diode bridge circuit.
As the inertial energy absorption load, an electric heating catalyst heater, a heating heater, a heater for heating hot water as a heating heat source, a window defrost heater, or the like can be used. These inertial energy absorption loads may be dedicated to inertial energy absorption when the engine is stopped, or those normally mounted on a vehicle may be used. In the latter case, the circuit may be designed so that power is supplied from the battery through a normal switch or switching element, and power is supplied from the AC machine through the switch or switching element that operates when the engine is stopped according to the present invention. The inertial energy absorption load may be provided individually for each phase of each armature coil of the AC machine, and a common inertial energy absorption load is rectified by rectifying the multiphase output voltage from each armature coil of the AC machine. You may make it supply electric power to.
[0024]
The signal related to the engine stop command may be, for example, a signal indicating that the engine speed due to the engine stop command decreases to a predetermined value or less.
Preferred aspects of the invention are described with reference to the following examples.
[0025]
[Example 1]
(Device configuration)
A first embodiment of a vehicle power unit according to the present invention will be described below with reference to a circuit diagram shown in FIG.
Reference numeral 1 denotes a conventionally known rotating field AC generator that excites a stator 11 and a rotor having three phase windings (armature coils) of U-phase, V-phase, and W-phase that are star-connected. It has a field coil 12 and a diode bridge (full wave rectifier circuit) 13 for rectifying the three-phase AC power voltage inputted from the output terminals 111, 112, 113 of each phase winding.
[0026]
The diode bridge 13 includes a diode set 131 that forms the upper arm of the three-phase full-wave rectifier circuit and a diode set 132 that forms the lower arm of the diode bridge 13. The diode bridge 13 includes a high-order DC output terminal 1311 and a low-order DC output terminal 1311. The DC output terminal 1321 is individually connected to the positive terminal and the negative terminal of the battery 2. In this embodiment, as in the prior art, the lower DC output terminal 1321 of the diode bridge 13 is connected to the negative terminal of the battery 2 through the vehicle body.
[0027]
Reference numeral 14 denotes a regulator that controls the field current flowing in the field coil 12, and the regulator 14 performs a known control for controlling the field current so as to read the voltage of the battery 2 and keep it at a predetermined level.
Reference numeral 3 denotes an in-vehicle load such as a headlamp, and 4 is a relay (a switch referred to in the present invention). One end of the load is passed through a diode set 6 that forms the upper arm of the second three-phase full-wave rectifier circuit. 6 is connected to the output terminals 111, 112, and 113, and the other end of the relay 4 is grounded through the load 5. The other end of the load 5 is connected to a DC output terminal 1321 on the lower side of the diode bridge 13 by a body earth circuit. The load 5 is composed of a low-impedance load such as a warm water heater, an electrically heated catalyst heater, a blower motor, or a defrost heater.
[0028]
Therefore, the AC output of the generator 1 is rectified by the second three-phase full-wave rectifier circuit having the diode set 6 as the upper arm and the diode set 132 as the lower arm, and is supplied to the load 5 through the relay 4. It is the composition which becomes. 7 is a controller for opening and closing the relay 4, and 8 is a relay for supplying power to the load 5 except when the engine is stopped, and is controlled by a controller (not shown). Note that the relay 8 can be omitted when the load (load for inertial energy absorption) 5 is a dedicated load that operates only when the engine is stopped or when the vehicle is braked.
[0029]
Next, the operation of this apparatus will be described.
The generator 1 is driven by a mechanically connected engine (not shown). The output of the generator 1 is rectified by the diode bridge 13 and supplied to the in-vehicle battery 2 and the load 3. When the vehicle enters a decelerating state by the driver's braking operation, the fuel is cut by an engine control ECU (not shown) and is rotated by the propeller shaft of the vehicle or is in an inertial rotation state after the clutch is disconnected.
[0030]
Since the generator 1 is driven by the engine, the generator 1 generates power and supplies electric power to the battery 2 and the load 3, and the input power for that purpose absorbs the rotational energy of the engine and lowers the engine speed. However, when the power generation voltage of the generator 1 is lower than the voltage of the on-vehicle battery 2, the external force for stopping the engine is mainly only the engine friction loss. At this time, the engine comes to a stop with torque fluctuation due to repeated compression and expansion. This is a factor causing resonance with the vehicle body, and if the engine rotation speed passes the rotation value corresponding to this resonance point promptly, the vehicle body resonance should be reduced.
[0031]
Therefore, in this embodiment, as described above, the controller 7 closes the relay 4 together with the input of the vehicle braking signal, feeds the output of the generator 1 to the load 5, and uses the kinetic energy of the vehicle as the motive power of the generator 1. In addition to reducing the brake load by absorbing the load, the relay 4 is kept on until at least the engine speed is less than the resonance speed value, so that the load 5 is maintained even in the engine speed range where the generated voltage is lower than the battery voltage. So that the engine speed can quickly pass the resonance speed value corresponding to the resonance point of the engine (that is, the engine speed value corresponding to the frequency at which the vehicle resonates with respect to engine torque fluctuations). Yes. Thereby, an unpleasant vehicle resonance phenomenon can be suppressed.
[0032]
That is, according to this embodiment, the load 5 can exhibit a braking force increasing effect when the vehicle is braked and a vehicle resonance reducing effect when the engine is stopped.
An example of the operation control of the controller 7 for the purpose of only the vehicle resonance reduction effect when the engine is stopped will be described with reference to FIG.
In response to the input of the engine stop command signal, the relay 4 is turned on (s1), waits until a predetermined time T elapses (s2), and when it elapses, the relay 4 is turned off (s3), and power is supplied from the battery 2 to the controller 7. Shut off.
[0033]
(Modification)
As shown in FIG. 3, the controller 7 that is supplied with the power supply voltage from the battery 2 through the power switch 70 conducts the excitation coil 40 of the relay 4 by the input of the engine stop command signal from the engine control ECU (not shown). Then, even if the power switch 70 is shut off by the engine stop command signal and the controller 7 is turned off, the rectified voltage of the diode set 6 is supplied to the exciting coil 40 of the relay 4. The diode set 6 can be energized to the load 5 until the generated voltage decreases until the contact voltage of the relay 4 cannot be maintained.
[0034]
In addition, the power supply voltage from the battery 2 to the controller 7 can of course be configured to last for a necessary time after the engine stop command signal is input. Reference numeral 71 denotes a transistor that drives and controls the relay 4.
(Modification)
In addition, as shown in FIG. 4, if the power supply voltage is supplied from the diode set 6 to the controller 7, the power supply to the controller 7 after the engine is turned off can be omitted. Reference numeral 72 denotes a transistor for driving and controlling the relay 4.
[0035]
(Modification)
The field current supplied to the field coil 12 may be increased by inputting a signal for instructing vehicle braking or an engine stop command signal to improve the braking effect or increase the power consumption of the load 5.
[0036]
[Example 2]
Another embodiment will be described below with reference to FIG.
The circuit shown in FIG. 5 is obtained by replacing the relay 4 with a bipolar npn power transistor 42 in the circuit shown in FIG.
Even in this case, the same operation and effect as those of the first embodiment can be realized.
[0037]
(Modification)
The vehicle braking effect can be improved by turning on the transistor 42 by inputting a signal for commanding vehicle braking (for example, a signal from a brake pedal depression amount detection sensor). However, in this case, if the engine speed is at a level at which the generator 1 can still charge the battery 2 sufficiently, the transistor 42 is not turned on, and it is further detected that the engine speed has dropped below that. Preferably, 42 is turned on.
[0038]
FIG. 6 shows an example of this vehicle braking control.
The routine is started by inputting a signal for commanding vehicle braking, and it is determined whether or not the generator 1 can sufficiently supply power to the battery 2 based on the engine speed (S11). Is turned on to start power consumption of the load 5 (S12), and it is checked whether or not braking is stopped (S13). If vehicle braking is stopped, the transistor 42 is turned off.
[0039]
[Example 3]
Another embodiment will be described below with reference to FIG.
The circuit shown in FIG. 7 is the same as the circuit shown in FIG. 1 except that the diode set 6, the load 5, the controller 7, and the relay 8 are omitted. Instead, the diode set 132 that forms the lower arm of the full-wave rectifier circuit 13 is modified. This is a diode / IGBT set 132 ′ that forms the lower arm of the full-wave rectifier circuit 13 ′.
[0040]
In each of the following embodiments, the IGBT may naturally be replaced with another type of three-terminal switching element such as a MOSFET.
The diode / IGBT set 132 ′ is obtained by connecting IGBT elements Tr in parallel in a grounded emitter manner to the three diodes constituting the diode set 132 of FIG.
[0041]
The operation of this circuit will be described below.
When the vehicle is decelerated because the vehicle is stopped, the engine is in an inertial rotation state, and the generated voltage of the generator becomes lower than the battery voltage, the controller 6 turns on all of the IGBT elements Tr of the lower arm. The windings of each phase are short-circuited, and most of the generator 1 power output is consumed as resistance loss in the stator 11. As a result, the decrease in the engine speed is accelerated and quickly passes through the resonance point with the vehicle body. 1 can have the same resonance reduction effect.
[0042]
An example of the control operation of the controller 6 at this time will be described with reference to the flowchart shown in FIG.
The routine is started by the input of the engine stop command signal. When the engine speed becomes less than the first rotation value N1 (S21), the IGBT element Tr (switching element in the present invention) is turned on (S22), and the engine speed is increased. Is less than the second rotation value N2 (S23), the IGBT element Tr is turned off (S24), and the process returns to the main routine (not shown). As in the first embodiment, the main routine is executed every predetermined time.
[0043]
In this embodiment, the first rotation value N1 is 20% higher than the resonance rotation value Nr, and the second rotation value N2 is 20% lower than the resonance rotation value Nr. The engine speed may be read directly from the sensor, the speed of the generator 1 may be read and converted, or may be estimated from the generated voltage of the generator 1.
In this way, since the inertia energy of the engine is absorbed only for a short period from the engine and the second rotation value N2 through the resonance rotation value Nr to the first rotation value N1, the heat generation of the generator 1 is suppressed. Car body resonance can be reduced. It should be noted that the generator 1 can rotate at a generated current of 0 until the engine speed reaches the second rotational value N2 to 0, and the heated armature coil can be cooled. Durability can be improved.
[0044]
As described above, instead of turning on and off the IGBT element Tr according to the engine speed, the elapsed time from the input time point of the vehicle braking signal or the engine stop command signal and the predetermined switch on time and switch off time set in advance. Similar control may be performed on the basis of the comparison. However, the switch-on time should be set at a time point when the engine speed is higher than the vicinity of the resonance speed value, and the switch-off time should be set at a time point when the engine speed is lower than the vicinity of the resonance speed value.
[0045]
[Example 4]
Another embodiment will be described below with reference to FIG.
The circuit shown in FIG. 9 is bidirectional in the circuit shown in FIG. 5 by connecting the IGBT element Tr in parallel to each diode D of the diode sets 131 and 132 of the full-wave rectifier circuit 13. This is converted to an AC-DC converter 13a.
[0046]
According to this configuration, the generator 1 can be motor-driven by the bidirectional AC-DC converter 13a to start the engine, and thereafter, known control can be performed to operate as a normal generator. Operates as a generator motor. Further, when the vehicle enters a deceleration stop state and the engine is fuel cut by the engine control ECU, the transistor 42 is turned on.
[0047]
As a result, as in the first embodiment, power is supplied to the load 5 from the full-wave rectifier circuit formed by the diode D on the lower arm side of the bidirectional AC-DC converter 13a and the diode set 6, and the vehicle is braked by the power consumption. The effect can be improved. Further, the vehicle resonance can be similarly reduced by inputting an engine stop command signal to the controller 7.
[0048]
(Modification)
When the above-described vehicle braking or engine stop command signal is input, the IGBT element Tr of the bidirectional AC-DC converter is intermittently controlled by, for example, vector control, and a rotating magnetic field formed by a field current in the armature coil of the stator 11 An in-phase rotating magnetic field is generated, and thereby the rotating magnetic field of the generator 1 as a whole can be enhanced to increase the generated voltage.
[0049]
In this way, the vehicle braking effect or the vehicle resonance reduction effect can be improved.
In FIG. 9, the diode set 6, the load 5, and the transistor 42 are omitted, and the three IGBT elements Tr on the lower arm side of the bidirectional AC-DC converter 13a are turned on, or the three IGBTs on the upper arm side are made conductive. By making the element Tr conductive, the same effect as in the second embodiment can be obtained due to a short circuit of the armature coil.
[0050]
[Example 5]
Another embodiment will be described below with reference to FIG.
The circuit shown in FIG. 10 is obtained by omitting the diode set 131, the load 5, and the transistor 42 of the full-wave rectifier circuit 13 from the circuit shown in FIG.
In this embodiment, the controller 7 that controls each IGBT element Tr of the bidirectional AC-DC converter 13a rotates the generator 1 in response to an input of a signal related to an engine stop command (or an input of a vehicle braking command). A multiphase AC voltage is applied so that torque is generated in the opposite direction (referred to as reverse driving), and a rotating magnetic field is formed by, for example, a vector control method. If it does in this way, electric power will be collect | recovered by the battery 2 through the IGBT element Tr as a result.
[0051]
According to this embodiment, the vehicle resonance can be reduced and the vehicle's inertial energy can be recovered to the battery. Further, since the circuit can be configured as a known engine direct-coupled generator motor with a regenerative braking function, Engine starting and regenerative braking can also be implemented.
Also in this case, the reverse drive control of the IGBT element Tr by the controller 6 may be performed, for example, during the conduction period of the transistor 42 shown in FIG.
[0052]
[Example 6]
Another embodiment will be described below with reference to FIG.
This embodiment shows one aspect of a load (load for inertial energy absorption) 5, wherein 100 is a hot water heater unit for an in-vehicle air conditioner, 102 is an engine hot water inlet, 103 is a distribution tube, 104 Is a radiating fin joined to the distribution tube 103, and the radiating fin 104 exchanges heat with an air flow formed by a blower (not shown) to form an air flow for heating. A warm water discharge port 105 returns to the engine via a radiator (not shown). Reference numeral 106 denotes an electric heater that constitutes the load 5 and includes an electric heating resistor 107 that warms hot water by heat generation.
[0053]
If it does in this way, the inertial energy of a vehicle can be used as a heat source for heating, and what is necessary is just to radiate with a radiator in summer.
(Modification)
In each of the above embodiments, the winding field type is adopted as the generator 1, but it goes without saying that it can be applied to a permanent magnet field type.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of a vehicle power unit according to the present invention.
FIG. 2 is a flowchart showing an operation example of the apparatus shown in FIG. 1;
FIG. 3 is a circuit diagram showing a modification of the apparatus shown in FIG.
FIG. 4 is a circuit diagram showing a modification of the apparatus shown in FIG.
FIG. 5 is a circuit diagram showing another embodiment of the vehicle power unit of the present invention.
6 is a flowchart showing an operation example of the apparatus shown in FIG.
FIG. 7 is a circuit diagram showing another embodiment of the vehicle power unit of the present invention.
8 is a flowchart showing an operation example of the apparatus shown in FIG.
FIG. 9 is a circuit diagram showing another embodiment of the vehicle power unit of the present invention.
FIG. 10 is a circuit diagram showing another embodiment of the vehicle power unit of the present invention.
FIG. 11 is a schematic sectional view showing another embodiment of the vehicle power unit of the present invention.
[Explanation of symbols]
1: Vehicle generator 2: Battery 4: Relay (switch)
42: Transistor (semiconductor switching element)
5: Load (Inertial energy absorption load)
6: Diode set forming the upper arm (half bridge forming the upper arm of the vibration suppression full-wave rectifier circuit)
7: Controller (control unit)
11: Stator 111, 112, 113 of generator 1: AC output terminal of generator 12: Field winding of generator 13: Diode bridge (full wave rectification circuit) of generator
131: Diode set (half bridge forming the upper arm of full-wave rectifier circuit for battery power supply)
132: Diode set (half bridge forming the lower arm of full-wave rectifier circuit)
14: Regulator 13a: Bidirectional AC-DC converter

Claims (5)

In a vehicular power unit including an AC machine driven by an engine, and a full-wave rectifier circuit that feeds power to a battery by full-wave rectification of power generated by the AC machine,
A switching element connected in parallel with the rectifier on the lower arm side or the rectifier on the upper arm side of the full-wave rectifier circuit;
A signal related to the engine stop command and a signal related to power supply from the alternator to the battery are input, and after the signal related to the engine stop command is input and from the alternator to the battery By turning on the switching element after the value becomes less than a predetermined level and maintaining the conduction until at least the rotational speed of the engine falls below a resonance rotational value corresponding to a resonance point of the vehicle body. A control unit that short-circuits the armature coil of the engine and absorbs the inertia energy of the engine as a resistance loss of the generator;
A vehicle power device comprising: The vehicle power unit according to claim 1 ,
The power supply for a vehicle that supplies power, wherein the switching element also serves as a part of an inverter circuit that converts DC power supplied from the battery into AC power for driving the AC machine. In a vehicle power unit comprising an AC machine coupled to an engine so as to be able to exchange torque, and a bidirectional AC-DC converter that exchanges power between the AC machine and a battery,
The bi-directional AC-DC converter is driven by a signal related to the engine stop command, and the driving is continued until at least the rotation speed of the engine falls below a resonance rotation value corresponding to a resonance point of the vehicle body. A controller that performs reverse direction driving to generate torque in the reverse rotation direction in the AC machine;
A vehicle power device comprising: In the vehicle power unit according to any one of claims 1 to 3 ,
The control unit is configured such that the engine speed is lower than the engine speed when the engine stop command is input and higher than the resonance speed value by a predetermined value or more, or from the signal input related to the engine stop command. Conducting the switch or switching element at the time of a predetermined first delay time or performing the reverse electric drive,
The vehicular power plant, wherein the first delay time is set such that the engine speed at the time when the first delay time is delayed is higher than the resonance speed value. The vehicle power unit according to any one of claims 1 to 4,
The control unit is configured to switch the switch or switching at a rotation number greater than 0 and lower than the resonance rotation value by a predetermined value or a predetermined second delay time from the signal input related to the engine stop command. Shut off the element or end the reverse electric drive,
2. The vehicle power unit according to claim 1, wherein the second delay time is set such that the engine speed when the second delay time is delayed is lower than the resonance speed value and greater than zero .

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