JP5852932B2 - Engine restart control device - Google Patents

Description

  The present invention relates to an engine restart control device.

  Conventionally, in a hybrid vehicle having an idle stop function, after the engine is requested to stop, the engine is connected to the pinion gear and the ring gear during the inertial rotation period, and when the engine is requested to re-accelerate, the engine starts immediately. (For example, Patent Document 1).

JP 2011-169331 A

  However, the connection of the pinion gear before the engine is stopped involves wear of the pinion gear, fatigue accumulation on the starter due to a collision torque, and the like, and thus there is a problem of promoting starter deterioration.

The present invention is used in a hybrid vehicle that travels in either an HEV mode in which travel drive force is obtained by an engine and a travel drive motor, or an EV mode in which travel drive force is obtained by the travel drive motor alone. In the engine restart control device that is connected / disconnected to the engine via the engine and starts the engine by a starter motor at the time of connection, the engine stop control is performed in response to an engine stop request that is output based on the driving situation of the vehicle A stop control unit, a determination unit that determines whether or not the engine speed is equal to or lower than a predetermined non-combustion rotation speed during stop control by the stop control section, and the engine rotation speed is the non-combustion rotation speed When the determination unit determines that the following is true, the starter motor, the engine, and And a connection control unit that controls the timing of connecting by the connecting mechanism, wherein the connection control unit, (a) is at the engine speed is less than the combustion recovery impossible rotational speed, and no re-depression of the accelerator pedal When the vehicle speed is equal to or higher than a predetermined value, a connection process between the starting electric motor and the engine by the connection mechanism is executed, and (b) the engine speed is equal to or lower than the non-combustion return speed, and the accelerator pedal When the vehicle speed is less than a predetermined value without stepping on again, the connecting process between the starting motor and the engine by the connecting mechanism is not executed .

  According to the present invention, the deterioration of the engine starter and acceleration performance can be reduced by changing the timing of connecting the engine and the starter motor according to the driving state of the vehicle during the engine stop control based on the engine stop request. It is possible to balance maintenance.

1 is a system configuration diagram of a hybrid vehicle according to an embodiment of the present invention. The flowchart explaining operation | movement of the engine restart control apparatus by embodiment Timing chart for explaining restart-oriented mode Timing chart for explaining deterioration protection priority mode

Hereinafter, an embodiment of an engine restart control device according to the present invention will be described with reference to the drawings. First, engine stop / restart control of a hybrid vehicle to which the present invention is applied will be described.
(1) Engine stop / restart control associated with accelerator pedal release A hybrid vehicle provided with an engine stop function targeted by the present invention is an HEV that travels with the driving force of both the travel motor (motor / generator) and the engine. The vehicle travels in one of a mode and an EV mode that travels only by the travel motor. Even when the vehicle is traveling in any mode, when the amount of depression of the accelerator pedal is reduced, the regenerative operation is performed, and the electric power generated by the traveling motor is charged to the battery.

  When the accelerator pedal is released and the regenerative operation mode is entered while traveling in the HEV mode, the fuel supply to the engine is stopped and the engine is stopped for the purpose of saving fuel. Further, the clutch between the engine and the motor generator is disconnected. As a result, the engine rotates due to inertia. In such a process of reducing the engine speed during the regenerative operation, the driver may step on the accelerator pedal again. When the starter and the engine are immediately connected for restarting the engine, the engine is rotating, so that the engagement of the pinion gear and the ring gear of the connection mechanism is not synchronized, and the durability of the connection mechanism is deteriorated. . If the starter is connected to the engine after the starter has been started to reach a certain number of revolutions, the restart responsiveness deteriorates.

  In the hybrid vehicle according to the present invention, when the driver re-depresses the accelerator pedal during the regenerative operation by releasing the accelerator pedal, the restartability emphasizing mode in which the engine restart responsiveness is given priority, and the responsiveness deteriorates, the starter It has a degradation protection priority mode that prioritizes the durability of the coupling mechanism with the engine rotation shaft.

(2) Engine stop / restart control when the SOC of the battery exceeds a predetermined value The present invention is not limited to the engine stop request by releasing the accelerator pedal, but when the SOC of the battery exceeds the predetermined value. The present invention is also applied to engine restart control at the time of an engine stop request when an engine stop request or a warm-up operation request ends. Here, a case will be described in which an engine stop request is output when the SOC of the battery exceeds a predetermined value.

  If the engine speed is reduced to a predetermined value or less due to the fuel cut, the engine cannot rotate independently only by returning the fuel injection. In the present specification, this predetermined value is referred to as a non-combustion rotation speed. For this reason, engine control is performed such that the engine speed does not fall below the combustion non-recoverable speed when the fuel cut control is entered due to an engine stop request. Under such circumstances, it is necessary to restart the engine when the engine speed becomes equal to or lower than the combustion non-recoverable speed due to fuel cut when the SOC of the battery becomes equal to or higher than a predetermined value.

  In this engine restart control, unlike the engine restart by depressing the accelerator pedal again, if the total value of the torque requested by the driver and the engine start torque is equal to or greater than the maximum torque of the motor / generator 3, the engine in the restartability emphasis mode is used. Perform restart control. When the total value of the torque requested by the driver and the engine starting torque is less than the maximum torque of the motor / generator 3, engine restart control is executed in the deterioration protection priority mode.

FIG. 1 is a system configuration diagram of a hybrid vehicle 100 equipped with a control device 50 according to the present embodiment.
As shown in FIG. 1, the hybrid vehicle 100 includes a high voltage battery 1, an inverter 2, a motor / generator 3, an engine 4, a low voltage battery 5, a starter 6, a pinion gear 11, and a ring gear 12. And a control device 50. Control device 50 includes a battery controller 7, a motor controller 8, an engine controller 9, and a hybrid controller 10.

  The motor / generator 3 is a synchronous motor / generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. The motor / generator 3 is driven and controlled by applying a three-phase AC voltage generated by the inverter 2 based on a control command from the motor controller 8. When the motor / generator 3 is supplied with power from the high-voltage battery 1, the motor / generator 3 performs a power running operation that functions as an electric motor by being driven to rotate. The motor / generator 3 functions as a generator that generates electromotive force at both ends of the stator coil when the rotor receives rotational energy from the engine 4 or the drive wheels, and charges the high-voltage battery 1.

  The engine 4 is a gasoline engine or a diesel engine. Based on the engine control command output from the engine controller 9, various controls such as engine start control, engine stop control, throttle valve opening control, and fuel cut control are performed. I do. The low voltage battery 5 supplies power to various auxiliary devices (not shown) mounted on the hybrid vehicle 100 to drive the auxiliary devices.

  The starter 6 is an electric motor for starting the engine 4 and is driven by a low voltage battery 5. The starter 6 is connected to the engine 4 by connecting a pinion gear 11 mounted on the starter 6 and a ring gear 12 mounted on the engine 4. As the starter 6 rotates, the pinion gear 11 rotates. The pinion gear 11 is pushed out and connected to the ring gear 12 by energizing a relay different from the drive relay for energizing the starter 6. A pinion gear 11, a ring gear 12, an extrusion device (not shown) that extrudes the pinion gear 11, and the like constitute a coupling mechanism.

  The hybrid controller 10 controls the driving of the hybrid vehicle 100 via the battery controller 7, the motor controller 8 and the engine controller 9. The hybrid controller 10 requires a driver's required torque based on outputs from a vehicle speed sensor 13a, an accelerator opening sensor 13b, a brake switch (brake sensor) 13c, an engine speed sensor 13d, and other various sensors (not shown). Driving power control is performed by calculating engine output, motor torque, and the like.

  Further, the hybrid controller 10 performs an idle stop function, that is, an automatic stop control and an automatic restart control of the engine 4 based on the outputs of the vehicle speed sensor 13a, the accelerator opening sensor 13b, the brake sensor 13c, and the engine speed sensor 13d. Run.

  In the engine restart control device according to the present invention, the engine stop / restart control is performed also when the SOC becomes equal to or lower than a predetermined value and the power generation operation is required, or when the warm-up operation request ends. In these engine stop controls, sensors different from various sensors for realizing the idle stop function are used. The SOC of the battery is calculated from the voltage of the high voltage battery and the charge / discharge current. In addition, the warm-up request and the end of the warm-up request are determined by measuring the outside air temperature with an outside air temperature sensor or the like to determine whether the engine needs to be warmed up.

The hybrid controller 10 executes engine stop control when the hybrid vehicle 100 is in the following driving states (1) to (3) while traveling.
(1) When the required driving force (requested torque) of the driver is below a predetermined value (2) When the power generation operation for charging the high-voltage battery 1 is unnecessary (3) When the warm-up request is completed The hybrid controller 10 When any one of the operating states (1) to (3) is detected, the engine 4 is automatically stopped via the engine controller 9 and control for restarting is executed.

The hybrid controller 10 executes engine restart control when the following operation states (4) to (6) are entered while the engine stop control is being executed.
(4) When the driver's required driving force (required torque) exceeds a predetermined value (5) When power generation operation for charging the high voltage battery 1 is required (6) When a warm-up request is output

  Hybrid vehicle 100 according to the present embodiment has an electric vehicle travel mode (hereinafter referred to as an EV mode) and a hybrid vehicle travel mode (hereinafter referred to as an HEV mode) as travel modes depending on the drive modes. Yes. The EV mode is a travel mode in which the motor / generator 3 is used as a drive source, and is selected by the hybrid controller 10 when the required torque is low and the SOC of the high voltage battery 1 is secured. In the EV mode, a motor travel mode and a regenerative travel mode are provided, and either mode is set.

The HEV mode is a mode in which the engine 4 and the motor / generator 3 are traveled as a travel drive source. When the required torque from the driver is high, the SOC is reduced to a predetermined value or less, and the warm-up request is output. In any of the cases, the hybrid controller 10 selects it. The HEV mode includes a motor assist travel mode, a power generation travel mode, and an engine travel mode, and any one of the modes is set.
The assist travel mode is a mode in which travel driving force is generated by the engine 4 and the motor / generator 3. The power generation travel mode is a mode in which the high voltage battery 3 is charged by generating power with the motor / generator 3 during travel. The engine travel mode is a mode in which the vehicle travels with the driving force of only the engine 4.

The following processing is executed by the control device 50. When an engine stop request is output during HEV traveling, fuel cut is performed. Thereafter, when an engine restart request is output, the pinion gear 11 and the ring gear 12 are connected to restart the engine. The engine restart control according to the present invention has two modes for connecting the pinion gear 11 and the ring gear 12 at two different timings.
Note that when the travel drive mode is switched to the EV mode after the engine stop request is output, a clutch (not shown) between the engine 4 and the motor / generator 3 is disconnected.

One mode of connecting the pinion gear 11 and the ring gear 12 is to start the engine 4 early when there is a restart request of the engine 4 before the engine 4 is stopped by the engine stop control accompanying the engine stop request. This is a mode for emphasizing restartability. Another mode in which the pinion gear 11 and the ring gear 12 are connected is a deterioration protection priority mode in which reduction of deterioration of the connection mechanism including the pinion gear 11 and the ring gear 12 is emphasized rather than early restart of the engine 4. .
Hereinafter, the restartability emphasis mode and the deterioration protection emphasis mode will be described in detail.

-Automatic engine stop / restart control when accelerator pedal is released-
In the engine automatic stop / restart control (hereinafter referred to as the first engine stop / restart control) accompanying the release of the accelerator pedal, an engine stop request is output when the driver releases the accelerator pedal and releases the accelerator pedal. Is done. With this engine stop request, engine stop control, that is, fuel cut is performed, and the engine speed decreases. If the engine speed falls below the engine speed at which combustion cannot be restored, it is necessary to crank the engine 4 during restart. When the accelerator pedal is released and the engine stop request is output when the vehicle speed is relatively high, there is a high possibility that the driver will request re-acceleration. On the other hand, when the accelerator pedal is released and an engine stop request is output when the vehicle speed is relatively low, the driver is unlikely to request re-acceleration. According to the driving tendency of the driver, in the present invention, when the vehicle speed is relatively high, the re-acceleration performance is emphasized, and when the engine speed is lower than the non-combustible rotation speed, the vehicle speed exceeds a predetermined value. If there is, control for connecting the starter 6 to the engine 4 in advance is performed in preparation for an engine restart request. On the other hand, in the present invention, when the vehicle speed is relatively slow, importance is attached to the deterioration protection performance of the starter coupling mechanism. If the vehicle speed is equal to or less than a predetermined value when the engine speed is lower than the non-combustible engine speed, the engine 4 The starter 6 is connected to the engine 4 and cranked in response to the restart request after the engine stops.

-Automatic engine stop / restart control when the SOC exceeds a predetermined value-
In this embodiment, the hybrid controller 10 outputs an engine stop request when the SOC of the high voltage battery 3 exceeds a predetermined value, and also when a warm-up request end is output because the warm-up operation is unnecessary. Outputs engine stop request. Here, the description will be made as engine automatic stop / restart control (hereinafter referred to as second engine stop / restart control) when the SOC is equal to or greater than a predetermined value. In the second engine stop / restart control, unlike the first engine stop / restart control, an engine stop request may be output when the accelerator pedal is depressed. Therefore, in this case, a restart request is not output when the accelerator pedal is depressed, and restartability is possible if the total value of the torque requested by the driver and the engine starting torque is equal to or greater than the maximum torque of the motor / generator 3. Execute engine restart control in the priority mode. When the total value of the torque requested by the driver and the engine starting torque is less than the maximum torque of the motor / generator 3, engine restart control is executed in the deterioration protection priority mode.

  The operation of the control device 50 according to the present embodiment will be described with reference to the flowchart shown in FIG. The program for performing the processing of FIG. 2 is stored in a memory (not shown) in the hybrid controller 10 and is activated and executed by the hybrid controller 10 at predetermined intervals after an ignition switch (not shown) is turned on.

  In step S201, the HEV traveling mode driven by the engine 4 and the motor / generator 3 is set, and the process proceeds to step S202. In step S202, it is determined whether a stop request for the engine 4 has been output. In response to the engine stop request, an engine stop control request is output to the engine controller 9. The engine controller 9 executes fuel cut control in response to the engine stop control request. The autonomous driving of the engine is stopped by the fuel cut, and the EV traveling mode is set when the engine speed becomes a predetermined value or less. When an engine stop request is output, an affirmative determination is made in step S202, a clutch (not shown) connecting motor / generator 3 and engine 4 is disconnected, and the process proceeds to step S203. If it is not determined that there is a request to stop the engine 4, a negative determination is made in step S202, the process returns to step S201, and the HEV travel mode is continued.

  In step S203, it is determined whether or not the rotational speed of the engine 4 is equal to or lower than the rotational speed at which combustion cannot be restored. If the rotational speed of the engine 4 is equal to or lower than the rotational speed at which combustion cannot be restored, that is, if the engine 4 cannot perform autonomous rotation without assistance, an affirmative determination is made in step S203 and the process proceeds to step S204. If the rotational speed of the engine 4 is larger than the rotational speed at which combustion cannot be restored, a negative determination is made in step S203 and the process returns to step S202.

  In step S204, it is determined whether or not the driver does not depress the accelerator pedal, that is, whether or not the accelerator pedal is released. If the accelerator pedal is not depressed, an affirmative determination is made in step S204 and the process proceeds to step S205. If the accelerator pedal is depressed, a negative determination is made in step S204 and the process proceeds to step S209 described later.

  In step S205, it is determined whether the vehicle speed is equal to or higher than a vehicle speed threshold value. If the vehicle speed is equal to or higher than the vehicle speed threshold, an affirmative determination is made in step S205 and the process proceeds to step S206. If the vehicle speed is less than the vehicle speed threshold, a negative determination is made in step S205 and the process proceeds to step S207. This vehicle speed threshold value is a vehicle speed during low-speed travel in which the vehicle travels at a relatively slow speed.

In step S206, a starter / engine connection process in the restartability emphasis mode is executed. As described above, the hybrid controller 10 performs a process of connecting the pinion gear 11 and the ring gear 12 in preparation for a re-acceleration request before the engine 4 whose rotational speed is reduced by the stop control is stopped. Specifically, the starter 6 is energized and rotated only for a predetermined time to push the pinion gear 11 in the direction of the ring gear 12. When the starter speed and the engine speed are synchronized, the starter 6 is directly connected to the engine 4. At this time, since the starter 6 is not energized, the engine is not cranked.
Thereafter, when the driver depresses the accelerator pedal, the starter 6 is energized and the engine 4 is started.

  In step S207, it is determined whether or not the engine 4 is stopped. If the engine 4 is stopped, an affirmative determination is made in step S207 and the process proceeds to step S208. If the engine 4 is not stopped, a negative determination is made in step S207 and the process returns to step S204.

  In step S208, starter / engine connection processing in the deterioration protection priority mode is executed. In the starter / engine connection process in this mode, the vehicle stops and the engine speed becomes zero. After that, for example, when a re-depressing operation of the accelerator pedal is detected, the starter 6 is energized to start the engine 4.

If a negative determination is made in step S204, the process proceeds to step S209. This is a processing procedure when an engine stop request is output due to the SOC of the high voltage battery 1 being equal to or greater than a predetermined value, and when an engine stop request is output when the warm-up request ends.
In step S209, it is determined whether or not the engine 4 can be restarted by the excess torque of the motor / generator 3 based on the required torque calculated using the accelerator opening that is the accelerator depression amount. If the total value of the accelerator required torque and the torque required for restarting the engine 4 is equal to or greater than the maximum torque of the motor / generator 3, an affirmative determination is made in step S209 and the process proceeds to step S206 described above. Perform engine connection processing. If the sum of the accelerator required torque and the torque required for restarting the engine 4 is less than the maximum torque of the motor / generator 3, a negative determination is made in step S204 and the process proceeds to step S208 described above, and the starter / engine in the deterioration protection priority mode Perform the concatenation process.

The starter / engine connection process in the restartability-oriented mode and the subsequent engine start process will be described with reference to the time chart of FIG. FIG. 3 shows an example of engine stop / restart control that accompanies accelerator pedal release.
−Restartability-oriented mode−
FIG. 3 is a timing chart for explaining the restartability emphasis mode. FIG. 3 (a) shows the change over time of the torque required from the driver, FIG. 3 (b) shows the change over time of the rotational speed of the engine 4 and the rotation speed of the pinion gear 11, and FIG. 3 (c) shows the vehicle speed sensor 13a. The time change of the vehicle speed detected by is shown.
In FIG.3 (b), the rotation speed of the engine 4 is shown with a continuous line, the rotation speed of the pinion gear 11 is shown with a broken line, and the rotation speed which cannot return combustion of the engine 4 is shown with a dashed-dotted line. The combustion non-recoverable rotational speed is a rotational speed at which autonomous rotation is impossible when there is no assistance from the starter 6, the motor / generator 3, or the like, that is, only by fuel re-injection. This non-combustible rotation speed is determined as a constant obtained in advance through experiments or the like and stored in advance in a memory (not shown) or the like.

  As shown in FIG. 3D, when the driver releases the accelerator pedal at time t1, an engine stop request is output as shown in FIG. After time t1, the driver request torque determined based on the accelerator pedal depression amount, that is, the output from the accelerator opening sensor 13b, starts to decrease. When the driver request torque becomes smaller than the predetermined value indicated by the one-dot chain line in FIG. 3A, the hybrid controller 10 transmits an engine stop control request to the engine controller 9. The travel drive mode is switched from the HEV mode to the EV mode.

  When the EV mode is switched, the fuel to the engine 4 is cut. As shown in FIG. 3B, at the time t3, the rotational speed of the engine 4 becomes smaller than the rotational speed where combustion cannot be restored. Further, in response to the release of the accelerator pedal at time t1, the vehicle speed starts to decrease as shown in FIG. In the example of FIG. 3, the vehicle speed exceeds the vehicle speed threshold indicated by the one-dot chain line in FIG.

  If the vehicle speed exceeds the vehicle speed threshold at the time point 3 when the engine speed becomes smaller than the non-combustible engine speed, the hybrid controller 10 shifts to the starter / engine connection process in the restartability-oriented mode. . When the hybrid controller 10 shifts to the starter / engine connection processing in the restartability-oriented mode at time t3, the pinion gear 11 and the ring gear are prepared in preparation for a restart request being output before the engine is stopped due to fuel cut. 12 are connected as follows.

  The hybrid controller 10 energizes the starter 6 through the engine controller 9 for a predetermined time through the engine controller 9 to rotate the pinion gear 11 inertially. Then, the engine controller 9 pushes out the pinion gear 11 during inertia rotation and connects it to the ring gear 12 (time t4). Thereafter, the accelerator pedal is depressed by the driver at time t5, and the hybrid controller 10 outputs a reacceleration request, that is, an engine restart request to the engine controller 9. The engine controller 9 energizes the starter 6 to restart the engine 4. When the rotational speed of the engine 4 reaches the rotational speed at which autonomous rotation is possible, the engine lid controller 10 releases the connection between the pinion gear 11 and the ring gear 12 at time t6.

The starter / engine connection process in the deterioration protection emphasis mode and the subsequent engine start process will be described with reference to the time chart of FIG. FIG. 4 shows an example of engine stop / restart control that accompanies release of the accelerator pedal.
-Deterioration protection mode-
FIG. 4 is a timing chart for explaining the deterioration protection emphasis mode. 4A shows the change over time of the torque required from the driver, FIG. 4B shows the change over time of the rotation speed of the engine 4 and the rotation speed of the pinion gear 11, and FIG. 4C shows the time of the vehicle speed. It shows a change. In FIG. 4B, as in FIG. 3B, the rotational speed of the engine 4 is indicated by a solid line and the rotational speed of the pinion gear 11 is indicated by a broken line.

  As shown in FIG. 4D, when the driver releases the accelerator pedal at time t1, an engine stop request is output as shown in FIG. After time t1, the driver request torque determined based on the output from the accelerator opening sensor 13b according to the accelerator pedal depression amount starts to decrease. When the driver request torque becomes smaller than the predetermined value indicated by the one-dot chain line in FIG. 4A, the hybrid controller 10 outputs an engine stop request. The travel drive mode is switched from the HEV mode to the EV mode.

  When the engine stop request is output and the mode is switched to the EV mode, the fuel to the engine 4 is cut. For this reason, as shown in FIG.4 (b), the rotation speed of the engine 4 begins to fall, and at the time t3, the rotation speed of the engine 4 becomes smaller than the rotation speed which cannot be returned to combustion. Further, as shown in FIG. 4C, the vehicle speed starts to decrease in response to the release of the accelerator pedal at time t1, and becomes smaller than the vehicle speed threshold value indicated by the alternate long and short dash line at time t2.

  When the rotational speed of the engine 4 becomes smaller than the rotational speed at which combustion cannot be restored, when the vehicle speed is equal to or lower than the vehicle speed threshold, the hybrid controller 10 proceeds to starter / engine connection processing in the deterioration protection priority mode. When the hybrid controller 10 shifts to the starter / engine connection process in the deterioration protection emphasis mode at time t <b> 3, the hybrid controller 10 does not connect the pinion gear 11 and the ring gear 12 while the engine 4 is rotating. That is, the hybrid controller 10 connects the pinion gear 11 and the ring gear 12 via the engine controller 9 between the times t4 and t5 after the engine 4 is stopped in the following procedure.

  The connection between the pinion gear 11 and the ring gear 12 is preferably performed at time t4 immediately after the engine 4 is stopped. Thereafter, when the accelerator pedal is depressed by the driver and the restart of the engine 4 is requested, the hybrid controller 10 energizes the starter 6 to restart the engine 4. When the rotational speed of the engine 4 reaches the rotational speed at which autonomous rotation is possible, the hybrid controller 10 releases the connection between the pinion gear 11 and the ring gear 12.

According to the engine restart control apparatus according to the embodiment described above, the following operational effects can be obtained.
(1) In the engine restart control device of the embodiment, stop control by fuel cut of the engine 4 is performed in response to an engine stop request. When the rotational speed of the engine 4 becomes equal to or lower than a predetermined combustion non-recoverable rotational speed due to the fuel cut, the timing when the starter 6 and the engine 4 are coupled by the coupling mechanisms 11 and 12 based on the driving state of the vehicle at that time. Be controlled.
Therefore, the timing for connecting the starter 6 and the engine 4 prior to engine restart is appropriately controlled according to the driving condition of the vehicle, and drivability and the reliability of the starter are improved.

(2) After the engine speed becomes equal to or lower than the engine speed at which combustion cannot be restored, when the accelerator pedal is not depressed again and the vehicle speed is equal to or higher than a predetermined value, the connection process between the starter 6 and the engine 4 is immediately executed. When the vehicle speed is less than the predetermined value, the connection process between the starter 6 and the engine is not immediately executed. When the vehicle speed is equal to or higher than a predetermined value, there is a high possibility that a re-acceleration request is output by the driver. Therefore, the starter 6 is connected to the engine 4 in advance so that the acceleration response is not impaired. When the vehicle speed is less than the predetermined value, it is unlikely that a re-acceleration request is output by the driver. Therefore, the starter 6 is not connected to the engine 4 in advance, and a restart request is output after the engine stops. Sometimes the engine 4 is restarted by the starter 6.

  When the engine is restarted after the engine stop control by the fuel cut, the engine 4 can be restarted at the optimal time for the driving state of the vehicle. As a result, the engine 4 can be started without deteriorating the acceleration performance of the vehicle, and the accumulation of fatigue due to the wear of the ring gear 12 or the collision torque can be suppressed. It is possible to achieve both of 6 deterioration suppression.

(3) In the engine restart control device of the embodiment, when it is detected that the state of the battery 1 is not required to be charged, for example, when the SOC is a predetermined value or more, an engine stop request is output. In this case, if the accelerator pedal is not released, if the sum of the required torque according to the depression of the accelerator pedal and the starting torque for restarting the engine is larger than the maximum torque of the motor / generator 3, the starter by the coupling mechanism is used. 6 and the engine 4 are connected. If the sum of the required torque and the engine starting torque is smaller than the maximum torque of the motor / generator 3, the connection process between the starter 6 and the engine 4 by the connection mechanism is not executed.

  When engine stop control by fuel cut is executed under such conditions, if the sum of the required torque and the engine start torque is larger than the maximum torque of the motor / generator 3, the excess torque (traveling driving force of the motor / generator 3). Cannot be restarted with torque other than For this reason, the starter 6 and the engine 4 are immediately connected to each other and the insufficient torque is shared by the engine 4. When the motor / generator 3 can be restarted with surplus torque, it is not necessary to immediately connect the starter 6 to the engine 4.

The embodiment described above can be modified as follows.
(1) The processes in the restartability emphasis mode and the deterioration protection emphasis mode described above may be executed by the engine controller 9 in place of those performed by the hybrid controller 10. That is, the engine controller 9 may execute the processing in the flowchart of FIG.
(2) The non-combustible rotation speed is stored in the memory as a table reference value associated with the water temperature in consideration of the fuel combustion efficiency, and the hybrid controller 10 reads out the table reference value according to the detected water temperature. The value may be determined as the rotation speed at which combustion cannot be restored.

(3) In step S205 of FIG. 3, SOC (State of Charge) or SOH (State of Health) may be used instead of performing the determination process using the vehicle speed.
(4) The motor / generator 3 may restart the engine 4 in response to the restart request. When the engine 4 is restarted by the motor / generator 3, the hybrid controller 10 connects the pinion gear 11 and the ring gear 12 before the restart of the engine 4, that is, before time t5 in FIG. Release it.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

3 Motor / generator 4 Engine 6 Starter 7 Battery controller 9 Engine controller 10 Hybrid controller,
11 Pinion gear 12 Ring gear,
50 Engine control device

Claims (5)

Used in a hybrid vehicle that travels in either an HEV mode that obtains travel driving force by an engine and a travel drive motor or an EV mode that obtains travel drive force by the travel drive motor alone, In an engine restart control device that is connected / disconnected to an engine and starts the engine by a starter motor when connected,
A stop control unit that performs stop control of the engine in response to an engine stop request that is output based on a driving situation of the vehicle;
A determination unit that determines whether or not the engine speed is equal to or lower than a predetermined non-combustible rotation speed during the stop control by the stop control unit;
When the determination unit determines that the engine speed is equal to or less than the rotation speed at which combustion cannot be restored, the starter motor and the engine are connected by the connection mechanism based on the driving state of the vehicle at that time. A connection control unit for controlling the timing ,
The connection control unit
(A) When the engine speed is equal to or lower than the non-combustible engine speed and when the accelerator pedal is not depressed again and the vehicle speed is equal to or higher than a predetermined value, the connection mechanism connects the starter motor and the engine. Run
(B) When the engine speed is equal to or less than the non-combustible engine speed and the accelerator pedal is not depressed again and the vehicle speed is less than a predetermined value, the connection between the starter motor and the engine by the connection mechanism An engine restart control device for a hybrid vehicle, characterized in that the processing is not executed . In the hybrid vehicle engine restart control device according to claim 1 ,
Wherein is the engine speed is less than the combustion recovery impossible rotational speed, and the connection processing of the vehicle speed without re-depression of the accelerator pedal and the connecting the starter motor and the engine by mechanism when less than a predetermined value is performed After that, when the accelerator pedal is depressed, the engine restart control device for a hybrid vehicle further includes a restart control unit that activates the starter motor and restarts the engine. In the hybrid vehicle engine restart control device according to claim 2 ,
The engine restart control device for a hybrid vehicle, wherein the engine stop request is output when the accelerator pedal is released. In the hybrid vehicle engine restart control device according to claim 2 ,
The engine stop request, the engine restart control apparatus for a hybrid vehicle, wherein the output when it is detected charging of the battery based on the battery SOC or SOH are unnecessary. The engine restart control device for a hybrid vehicle according to any one of claims 1 to 4 ,
The engine stop request is output when it is detected that the state of a battery that supplies power to the electric motor for traveling drive is a state that does not require charging,
The connection control unit includes:
(A) when there is a re-depression of the accelerator pedal, if the sum of the starting torque for restarting the required torque and the engine in response to the depression of the accelerator pedal is greater than the maximum torque of the traveling drive motor, Performing a connection process between the starter motor and the engine by the connection mechanism;
(B) when there is a re-depression of the accelerator pedal, if the sum of the starting torque for restarting the required torque and the engine in response to the depression of the accelerator pedal is less than the maximum torque of the traveling drive motor, The engine restart control device for a hybrid vehicle, wherein the connection process between the starter motor and the engine by the connection mechanism is not executed.

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