JP2011162006A - Drive control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive control device for a vehicle, certainly providing a stall of an internal combustion engine when a rotation speed of each drive wheel rapidly decreases by rapid braking of the vehicle. <P>SOLUTION: The drive control device for the vehicle includes: the internal combustion engine 10 having an output shaft connectable to the drive wheels 4 of the vehicle 1; a dynamo-electric machine 20 connectable to the drive wheels 4; a detection means 23 provided in the dynamo-electric machine 20, and detecting a rotation speed of the dynamo-electric machine 20; a rapid braking decision means 31 deciding the rapid braking of the vehicle 1 based on a change amount of the rotation speed of the dynamo-electric machine 20 detected by the detection means 23 within a prescribed period, in a state in which the dynamo-electric machine 20 is connected to the output shaft of the internal combustion engine 10; and a rotation speed control means 33 driving the dynamo-electric machine 20 based on a decision result of the rapid braking decision means 31 to control the rotation speed of the dynamo-electric machine 20 such that driving force is imparted to the internal combustion engine 10 from the dynamo-electric machine 20, to maintain the rotation speed of the internal combustion engine 10 to a higher rotation speed than a lower limit rotation speed allowing the prevention of the stall of the internal combustion engine 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle drive control device that prevents an internal combustion engine from stalling when the vehicle is suddenly braked.

  BACKGROUND ART A hybrid vehicle that uses an internal combustion engine and a drive motor as power sources includes a drive control device that transmits drive force output from the internal combustion engine and the drive motor to drive wheels. This vehicle drive control device has, for example, a planetary gear unit, and controls the drive of the vehicle by appropriately connecting or releasing an internal combustion engine, a drive motor, drive wheels, a generator, and the like. Further, the vehicle drive control device controls the regeneration of the vehicle that transmits the rotational force of the drive wheels to the drive motor when the vehicle decelerates and generates electric power by the drive motor.

  Here, when the vehicle is subjected to sudden braking such as a brake operation by the driver, the vehicle suddenly decelerates, and the rotational speed of the drive wheels also decreases with this sudden deceleration. At this time, if the internal combustion engine and the drive motor are respectively connected to the drive wheels by the vehicle drive control device, an overload is applied to the internal combustion engine, which may cause the internal combustion engine to stall. In particular, when the rotational speed of the internal combustion engine is low, that is, when the vehicle is traveling at a low speed, if the vehicle is suddenly braked, the possibility that the internal combustion engine will stall increases. Thus, for example, Japanese Patent Application Laid-Open No. 2004-316693 (Patent Document 1) discloses a drive control device that prevents a stall of an internal combustion engine when a sudden braking occurs during low-speed traveling of a vehicle.

2004-316693

  However, when the vehicle is traveling on a low mu road such as a humid road surface, if the vehicle is suddenly braked, the drive wheels may be locked or close to being locked. At this time, the number of rotations of the drive wheels is more drastically reduced than the reduction due to the sudden deceleration of the vehicle. In such a case, the drive control device disclosed in Patent Document 1 may not be in time for control and may stall the internal combustion engine.

  The present invention has been made in view of the above problems, and provides a vehicle drive control device capable of reliably preventing a stall of an internal combustion engine when the rotational speed of a drive wheel suddenly decreases due to sudden braking of the vehicle. The purpose is to do.

In order to solve the above problem, the feature of the invention according to claim 1 is:
An internal combustion engine having an output shaft connectable to drive wheels of the vehicle;
A rotating electric machine connectable to the drive wheel;
Detection means provided in the rotating electrical machine for detecting the rotational speed of the rotating electrical machine;
In a state in which the rotating electrical machine is connected to the output shaft of the internal combustion engine, the sudden braking of the vehicle is determined based on the amount of change in the rotational speed of the rotating electrical machine detected by the detection means within a predetermined period. Sudden braking determination means;
In order to maintain the rotational speed of the internal combustion engine higher than the lower limit rotational speed capable of preventing the stall of the internal combustion engine, the rotating electrical machine is driven based on the determination result of the sudden braking determination means. A rotational speed control means for controlling the rotational speed of the rotating electrical machine so as to apply a driving force to the internal combustion engine;
It is to provide.

The feature of the invention according to claim 2 is that in claim 1,
The sudden braking determination means determines sudden braking of the vehicle based on a change amount of the rotational speed of the rotating electrical machine detected by the detection means and a control signal for antilock brake control of the vehicle.

A feature of the invention according to claim 3 is that in claim 1 or 2,
The rotational speed control means controls the rotational speed of the rotating electrical machine so as to apply a driving force to the internal combustion engine, so that the rotational speed of the internal combustion engine is near the rotational speed at idling from the lower limit rotational speed. Feedback control of the rotating electrical machine based on the rotational speed of the rotating electrical machine so that the rotational speed is up to a predetermined rotational speed.

A feature of the invention according to claim 4 is that in any one of claims 1 to 3,
In a state where the rotational speed control means controls the rotational speed of the rotating electrical machine so as to apply driving force to the internal combustion engine, the vehicle speed of the vehicle, the rotational speed of the internal combustion engine, and the antilock brake of the vehicle It is further provided with cancellation determination means for determining whether to cancel the control of the rotational speed of the rotating electrical machine by the rotational speed control means based on at least one of the control signals of the control.

  According to the first aspect of the present invention, the sudden braking determination means determines whether or not the vehicle is suddenly braked, and in the case of sudden braking, a driving force is applied from the rotating electrical machine to the internal combustion engine. Thereby, for example, when the vehicle is traveling on a low mu road at a low speed, the vehicle is suddenly braked, and the internal combustion engine can be prevented from stalling even if the rotational speed of the drive wheels is suddenly reduced.

  The sudden braking determination means determines sudden braking of the vehicle in a state where the rotating electrical machine is connected to the output shaft of the internal combustion engine. Here, for example, a hybrid vehicle that uses an internal combustion engine and a rotating electrical machine as power sources switches the output of the internal combustion engine and the rotating electrical machine in accordance with vehicle information, a running state, and the like. That is, when the internal combustion engine and the rotating electrical machine are used as the driving source, when either one is used as the driving source, the internal combustion engine may be used as the driving source and the rotating electrical machine may be used as the generator. The state in which the rotational speed of the drive wheels rapidly decreases due to sudden braking of the vehicle and an overload is applied to the internal combustion engine is a state in which at least the rotating electrical machine is connected to the internal combustion engine. Therefore, the rotating electrical machine is in a state of being directly connected to the driving wheel of the vehicle or indirectly connected via the output shaft of the internal combustion engine.

  As a result, the drive control device can detect the rotation speed of the drive wheel by detecting the rotation speed of the rotating electric machine by the detecting means for detecting the rotation speed of the rotating electric machine. That is, it is possible to detect the amount of change in the rotational speed of the drive wheel based on the amount of change in the rotational speed of the rotating electrical machine obtained from the rotational speed of the rotating electrical machine detected within a predetermined period. Therefore, it is possible to determine the sudden braking of the vehicle based on the amount of change in the rotational speed of the rotating electrical machine. This “predetermined period” is a period during which the detection means can sample the rotational speed of the rotating electrical machine a plurality of times. By adopting such a configuration, it is possible to immediately respond to sudden braking when the vehicle is traveling at a low speed, and thus it is possible to more reliably prevent the internal combustion engine from stalling.

  In general, for example, a sensor such as an encoder or a resolver is used as the detection means for detecting the rotation speed of the rotating electrical machine. Since such a sensor has a higher resolution than a sensor that directly detects the rotational speed of the drive wheel, the rotational position and rotational speed of the rotating electrical machine can be detected with high accuracy. Thereby, compared with the case where the rotation speed of a driving wheel is detected, the variation | change_quantity of the rotation speed of a driving wheel can be detected more accurately. Therefore, the sudden braking determination means can determine the sudden braking of the vehicle with higher accuracy based on the amount of change in the rotational speed of the rotating electrical machine (that is, the amount of change in the rotational speed of the drive wheel).

  Further, the rotational speed control means controls the rotational speed of the rotating electrical machine so as to drive the rotating electrical machine and apply a driving force to the internal combustion engine based on the determination result of the sudden braking determination means. This is because the rotational speed of the internal combustion engine is maintained at a higher speed than the lower limit rotational speed at which the internal combustion engine can be prevented from stalling by the rotational speed control means. Here, the “lower limit rotational speed” of the internal combustion engine is a lower limit value of the rotational speed at which the internal combustion engine can be driven without stalling.

  In other words, the rotational speed control means is configured so that when the vehicle is suddenly braked, the rotational speed of the rotating electrical machine connected to the output shaft of the internal combustion engine is set so that the rotational speed of the internal combustion engine does not fall below the lower limit rotational speed. Is controlling. Thus, since the rotation speed control means is based on the sudden braking of the vehicle determined with high accuracy by the sudden braking determination means, the rotation speed of the rotating electrical machine can be controlled appropriately. Therefore, when the vehicle is suddenly braked and the drive wheels are locked or close to the lock, and the rotation speed of the drive wheels is suddenly reduced, it is possible to reliably prevent the internal combustion engine from stalling.

  According to the invention of claim 4, the sudden braking determination means performs sudden braking of the vehicle based on a control signal for antilock brake (ABS) control of the vehicle in addition to the amount of change in the rotational speed of the rotating electrical machine by the detection means. It is the structure which determines. The ABS control prevents the driving wheels from being locked during braking of the vehicle, and is executed based on a control signal output from the vehicle. Therefore, the sudden braking determination means more accurately determines that sudden braking has been applied to the vehicle by determining sudden braking of the vehicle based on the amount of change in the rotational speed of the rotating electrical machine and the control signal of the ABS control. can do. Therefore, stalling of the internal combustion engine can be prevented more reliably.

  According to the invention of claim 5, the rotational speed control means is configured to feedback control the rotating electrical machine based on the rotational speed of the rotating electrical machine. In a state where the rotation speed of the rotating electrical machine is controlled by the rotation speed control means, the vehicle is subjected to sudden braking such as a brake operation by the driver. Therefore, if the rotational speed of the internal combustion engine is increased too much, the braking distance may be affected. Therefore, by performing feedback control of the rotating electrical machine, it is possible to prevent the internal combustion engine from stalling without affecting the braking distance of the vehicle by not exceeding a predetermined rotational speed in the vicinity of the rotational speed when idling the internal combustion engine. Can do.

  According to the fifth aspect of the present invention, the vehicle drive control device further includes a cancellation determination unit that determines whether to cancel the control of the rotation speed control unit. As a result, the vehicle drive control device can properly cancel the rotational speed control of the rotating electrical machine, and thus can prevent a load from being applied to the internal combustion engine and the drive wheels.

It is a block diagram of the hybrid type vehicle carrying a drive control apparatus. It is a flowchart which shows drive control. It is a flowchart which shows sudden braking determination. It is a flowchart which shows the cancellation | release determination of drive control. It is a graph which shows the relationship between the rotation speed of a drive motor at the time of sudden braking, and time.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of a vehicle drive control device according to the invention will be described with reference to the drawings. A vehicle equipped with the drive control device of the present invention will be described as a hybrid vehicle using an internal combustion engine and a drive motor as power sources.

<Configuration of drive control device>
The drive control apparatus 2 of the hybrid type vehicle 1 of embodiment is demonstrated with reference to FIG. The hybrid vehicle 1 uses an engine 10 (corresponding to “internal combustion engine” of the present invention) and a drive motor 20 (corresponding to “rotating electric machine” of the present invention) as power sources. The hybrid vehicle 1 includes a drive control device 2 that controls the driving force of each power source, a plurality of sensors 3 that detect various vehicle information, and drive wheels 4 that are rotated by the driving force.

  The drive control device 2 includes an engine 10, a drive motor 20, and an ECU 30. The engine 10 is an internal combustion engine such as a gasoline engine or a diesel engine that generates a driving force by burning fuel. The driving force by the engine 10 is output to the planetary gear unit 11 via the output shaft of the engine 10. Further, the engine 10 is controlled by a later-described engine control unit 32 of the ECU 30 such as the throttle valve opening, fuel injection amount, and ignition timing.

  The planetary gear unit 11 is a mechanism that mechanically synthesizes and distributes the driving force, and connects the engine 10 and the driving motor 20 so as to be differentially rotatable. The planetary gear unit 11 receives a driving force from the engine 10 and the driving motor 20 and outputs the driving force to the driving wheels 4 via the transmission 12. The transmission 12 is controlled by the transmission control unit 34 of the ECU 30 based on the operation of the driver's shift lever, and shifts the rotation of the drive wheels 4 and the output shaft of the planetary gear unit 11.

  The drive motor 20 is connected to a battery 22 that is a power storage device via an inverter 21. The inverter 21 receives a control signal from a motor control unit 33 (corresponding to “rotational speed control means” of the present invention) of the ECU 30 and appropriately switches the state of the drive motor 20. The state of the drive motor 20 mainly includes a drive state in which power is supplied from the battery 22 and rotationally driven at a predetermined rotational speed, a regenerative state in which the battery 22 is charged by generating electric power by the rotational force transmitted from the drive wheels 4, and driving There is an unloaded state in which the rotating shaft of the motor 20 can freely rotate. Further, the drive motor 20 is provided with a motor rotation number sensor 23 (corresponding to the “detection means” of the present invention) that detects the rotation number of the drive motor 20. In this embodiment, the motor rotation speed sensor 23 includes a sensor having high resolution such as an encoder or a resolver, detects the rotation speed of the drive motor 20 every 2 ms, and outputs a detection result to the ECU 30 as a signal.

  The ECU 30 is an electronic control unit mainly composed of a microcomputer, and receives vehicle information such as a vehicle speed and a shift position in the vehicle by various sensors. The ECU 30 includes a hybrid control unit 31 (corresponding to the “rapid braking determination unit” of the present invention), an engine control unit 32, a motor control unit 33, a transmission control unit 34, and an ABS control unit 35. is doing.

  The hybrid control unit 31 switches the output by the engine 10 and the drive motor 20 based on the vehicle information input from the various sensors 3 and the running state of the vehicle. When the engine 10 and the drive motor 20 are drive sources in accordance with the switching of the output, when either one is the drive source, the engine 10 may be the drive source and the drive motor 20 may be the generator. The hybrid control unit 31 performs hybrid control such as output switching in the hybrid vehicle 1 by integrally controlling the control units 32 to 35 described later. Further, the hybrid control unit 31 determines whether or not the vehicle is suddenly braked while the vehicle is running, and sends a control signal for starting or stopping the rotational speed control to the motor control unit 33 in order to prevent the engine 10 from stalling. Output. Details will be described later.

  The engine control unit 32 receives a signal of an engine speed detected by an engine speed sensor (not shown). Then, the engine control unit 32 outputs a control signal to, for example, a throttle valve actuator (not shown) according to the detected engine speed and the target engine speed based on the driver's accelerator operation or the like. Thereby, the rotation speed of the engine 10 is controlled by adjusting the opening degree of the throttle valve of the engine 10.

  The motor control unit 33 receives a signal of the rotational speed of the drive motor 20 detected by the motor rotational speed sensor 23. Then, the motor control unit 33 outputs a control signal to, for example, the inverter 21 in accordance with the detected rotational speed of the drive motor 20 and the target motor rotational speed based on the traveling state of the vehicle, the capacity of the battery 22, and the like. . Thereby, the voltage applied to the drive motor 20 is adjusted, and the rotation speed of the drive motor 20 is controlled. Further, the motor control unit 33 inputs a control signal for rotational speed control output from the hybrid control unit 31 when the rotational speed of the drive wheel 4 rapidly decreases due to sudden braking of the hybrid vehicle 1, and the control signal is input to this control signal. Based on this, the rotational speed of the drive motor 20 is controlled so as to prevent the engine 10 from stalling.

  This rotational speed control is performed by rotating the drive motor 20 so that the motor control unit 33 drives the drive motor 20 to apply a drive force to the engine 10 based on a determination result of a sudden braking determination by the hybrid control unit 31 described later. The number is controlled. As a result, the engine 10 is maintained at a higher rotation speed than the lower limit rotation speed at which the engine 10 can be prevented from stalling when sudden braking is applied to the vehicle. Here, the “lower limit rotational speed” is a lower limit value of the rotational speed at which the engine 10 can be driven without stalling. In this embodiment, the rotational speed of about 600 rpm is experimentally obtained as the lower limit value. . That is, during sudden braking, the rotational speed of the drive motor 20 connected to the output shaft of the engine 10 is controlled so that the rotational speed of the engine 10 does not fall below this lower limit rotational speed.

  Further, the motor control unit 33 feedback-controls the drive motor 20 based on the rotation speed of the drive motor 20 detected by the motor rotation speed sensor 23. In a state where the rotational speed of the drive motor 20 is controlled during the execution of the rotational speed control, the hybrid vehicle 1 is suddenly braked by, for example, a brake operation by the driver. Therefore, it is necessary to suppress an increase in the rotational speed of the engine 10 so as not to affect the braking distance. Therefore, by performing feedback control of the drive motor 20, the rotational speed control is executed so as not to exceed a predetermined rotational speed in the vicinity of the rotational speed when the engine 10 is idling. Details regarding execution or cancellation of the rotational speed control will be described later.

  The transmission control unit 34 outputs a control signal to the transmission 12 so as to switch and control the gear position of the transmission 12 according to the vehicle speed, the throttle valve opening by the accelerator operation, the shift position, and the like. The ABS control unit 35 executes anti-lock brake (ABS) control for preventing the drive wheels 4 from being locked when the hybrid vehicle 1 is braked. The ABS control unit 35 receives the vehicle speed detected by the various sensors 3 and the rotational speeds of the plurality of drive wheels 4. Then, the ABS control unit 35 outputs a control signal so as to adjust the braking force of the brake so as to prevent the drive wheels 4 from being locked when the vehicle is braked by a driver's braking operation or the like. To execute ABS control.

<Rotational speed control>
Next, the rotational speed control of the drive motor 20 by the motor control unit 33 of the ECU 30 will be described with reference to FIGS. As described above, the rotational speed control is to control the rotational speed of the drive motor 20 in order to prevent the engine 10 from stalling. FIG. 2 is a flowchart showing drive control. FIG. 3 is a flowchart showing the sudden braking determination. FIG. 4 is a flowchart showing determination of canceling drive control. FIG. 5 is a graph showing the relationship between the rotational speed of the drive motor and time when there is sudden braking.

  First, the hybrid control unit 31 of the ECU 30 acquires vehicle information from the various sensors 3 (step 1. Hereinafter, abbreviated as S1. The same applies to other steps). The vehicle information acquired in S1 includes a shift position, vehicle speed, engine speed, and the like. Next, the ECU 30 determines from the shift position acquired in S1 whether the driver is in the drive range of the shift lever (S2). Here, the drive range means that when the vehicle has an automatic transmission (AT), the vehicle moves forward by an accelerator operation such as D (Drive), 4 to 2, L (Low), and R (Reverse). Or the range that moves backwards. Therefore, ranges such as P (Parking) and N (Neutral) where the engine 10 and the drive motor 20 that are power sources are not connected to the drive wheels are not included.

  When the shift position is in the drive range (S2: Yes), the ECU 30 determines whether the vehicle speed acquired in S1 is smaller than a preset threshold value (S3). On the other hand, when the shift position is not in the drive range (S2: No), the ECU 30 determines that the rotation speed control is unnecessary, and proceeds to S12. In S3, the preset threshold value is a value that can be regarded as low-speed traveling when traveling at a vehicle speed lower than the threshold. This threshold value is set to the maximum speed at which the engine 10 may stall when sudden braking is applied to the vehicle and the drive wheels 4 are locked. In the present embodiment, the threshold is set to about 10 to 20 km / h. If the vehicle speed is less than this threshold (S3: Yes), the process proceeds to S4. On the other hand, when the vehicle speed is equal to or higher than the threshold (S3: No), the ECU 30 determines that the rotation speed control is unnecessary, and proceeds to S12.

  In S4, the hybrid control unit 31 compares the engine speed acquired in S1 with a predetermined value. In S4, the predetermined value compared with the engine speed is the maximum value of the engine speed at which the engine 10 may stall when an overload is applied to the engine 10 rotating at a speed less than the predetermined value. Is set. When the hybrid vehicle 1 is traveling with the drive wheels 4 and the engine 10 connected, the engine 10 is overloaded by the lock of the drive wheels 4. On the other hand, if the drive wheel 4 and the engine 10 are not connected to each other by other clutch control, or if the vehicle is running in a half-clutch state, even if the drive wheel 4 is locked, the engine 10 Is not overloaded.

  Therefore, after determining whether or not the vehicle is traveling at a low speed in S3, the hybrid control unit 31 may stall the engine 10 if the rotational speed of the engine 10 is less than a predetermined value in S4 (S4: Yes). Therefore, the sudden braking determination (S5) is performed. On the other hand, if the rotational speed of the engine 10 is equal to or greater than the predetermined value (S4: No), the drive wheel 4 and the engine 10 are not connected. Therefore, the ECU 30 determines that the rotational speed control is unnecessary, and S12 Migrate to

  In S5, as shown in FIG. 3, the hybrid control unit 31 performs a sudden braking determination for determining whether the vehicle is suddenly braked. In the present embodiment, the sudden braking is determined based on the amount of change ΔR in the rotational speed of the drive motor 20 within a predetermined period. The hybrid control unit 31 stores in the ECU 30 the rotational speed of the drive motor 20 that is input from the motor rotational speed sensor 23. Then, as shown in FIG. 5, the hybrid control unit 31 calculates the change amount ΔR from the difference between the current rotation speed Rr and the rotation speed Rp detected a predetermined time period ΔT before the current time (S51).

  The change amount ΔR calculated in S51 corresponds to the change amount of the rotational speed of the drive motor 20. Further, the predetermined period ΔT is a period set based on an interval at which the process related to the rotational speed control shown in FIG. In the present embodiment, the predetermined period ΔT is set to 100 ms at which the rotation speed of the drive motor 20 detected by the motor rotation speed sensor 23 can be sampled about 50 times.

  Next, the ECU 30 compares the amount of change ΔR with a preset threshold value (S52). In S52, the preset threshold value is a value that can be considered that the rotational speed of the drive wheel 4 has rapidly decreased when the amount of change ΔR in the rotational speed of the drive motor 20 is larger than the threshold value. Here, the drive motor 20 connected to the engine 10 is in a state of being directly connected to the drive wheel 4 or indirectly connected via the output shaft of the engine 10. That is, by detecting the rotation speed of the drive motor 20 by the motor rotation speed sensor 23, the rotation speed of the drive wheel 4 is detected with high accuracy, and the change amount ΔR (the change amount of the rotation speed of the drive motor 20). ) Is determined by the hybrid control unit 31.

  When the amount of change ΔR in the rotational speed of the drive motor 20 is larger than the threshold (S52: Yes), the vehicle is suddenly braked, and the hybrid control unit 31 determines that the rotational speed of the drive wheels 4 has suddenly decreased. Then, a sudden braking signal is output (S53). On the other hand, when the amount of change ΔR in the rotational speed of the drive motor 20 is equal to or smaller than the threshold value (S52: No), the ECU 30 determines that the rotational speed control is unnecessary, and no sudden braking signal is output. And the sudden braking determination in S5 is complete | finished, and it transfers to S6.

  Subsequently, as shown in FIG. 2, in the sudden braking determination of S5, the ECU 30 determines whether or not a sudden braking signal is output (S6). When the sudden braking signal is not output (S6: No), the ECU 30 determines that the rotation speed control is unnecessary, and proceeds to S12. On the other hand, when the sudden braking signal is output (S6: Yes), the ECU 30 determines whether the control flag is ON or OFF (S7). Here, the “control flag” is a flag for monitoring whether the hybrid control unit 31 is executing the rotation control by the motor control unit 33. When this control flag is turned ON, a control signal for starting the rotation speed control is output from the hybrid control section 31, and the motor control section 33 executes the rotation speed control. Further, when the control flag is turned off, a control signal for canceling the rotation speed control is output from the hybrid control section 31, and the motor control section 33 cancels the rotation speed control. Therefore, the rotational speed control is always executed while the control flag is ON.

  In other words, in S7, the ECU 30 determines whether the rotational speed control is being executed by determining whether the control flag is ON / OFF. When the control flag is OFF (S7: No), the rotational speed control is not executed, and the rotational speed control is started by turning the control flag ON (S8). And a control timer is started (S9) and a process is complete | finished. This control timer is for measuring the execution time of the rotational speed control.

  On the other hand, when the control flag is ON (S7: Yes), the rotational speed control has already been executed, and the ECU 30 determines whether to cancel the rotational speed control (S10). In S <b> 10, as shown in FIG. 4, the ECU 30 determines whether to continue or cancel the rotation speed control being executed by the motor control unit 33. First, the ECU 30 compares the timer value, which is the execution time of the rotational speed control, with a threshold value (S101). The threshold value in S101 is a period in which the rotation speed control is assumed, and the safety in a series of controls is improved by determining whether or not the execution time is within this period. Therefore, when the timer value is equal to or greater than the threshold value (S101: No), it is determined that the rotation speed control is to be canceled, and the ECU 30 outputs a cancellation signal (S104) and ends the process.

  When the timer value is less than the threshold value (S101: Yes), the ECU 30 acquires vehicle information (S102). The vehicle information acquired here includes a vehicle speed, an engine speed, and a control signal from the ABS control unit 35. Then, the ECU 30 determines continuation or cancellation of the rotational speed control based on the vehicle information (S103). In S103, first, the ECU 30 determines whether or not the vehicle is stopped. For example, when braking is applied to the vehicle and the vehicle speed becomes zero as it is, the vehicle is in a stopped state, so the rotational speed of the drive wheels 4 is also zero, and it is determined that the rotational speed control is cancelled.

  Next, the ECU 30 determines whether the engine speed is greater than a predetermined speed. The predetermined rotational speed in S103 is set in advance near the rotational speed when the engine 10 is idling. In the present embodiment, the predetermined rotational speed is set to a rotational speed obtained by adding about 100 rpm to the rotational speed during idling. For example, when the engine speed is greater than the predetermined speed, it is considered that the vehicle has shifted from braking to an acceleration state, and it is determined that the speed control is to be released.

  In S103, the ECU 30 finally determines whether the ABS control is released. In a vehicle equipped with a control device for ABS control, when sudden braking is applied to the vehicle, ABS control may be executed based on the vehicle speed, the number of rotations of each of the plurality of drive wheels 4, and the like. That is, when the ABS control is released, it is considered that the lock state of the drive wheels 4 is avoided, and the possibility that the engine 10 will stall is low, and it is determined that the rotation speed control is released. Therefore, in the case of a vehicle including an ABS control device, an ABS control signal may be used. As described above, when it is determined that the rotational speed control is to be cancelled, in S104, the ECU 30 outputs a cancel signal and ends the process. As described above, S10 determines whether to release the rotation control drive by the motor control unit 33 based on the vehicle information, and corresponds to “release determination means”.

  Subsequently, as shown in FIG. 2, in the release determination of S10, the ECU 30 determines whether a release signal is output (S11). When the release signal is not output (S11: No), the ECU 30 ends the process because the rotation speed control is continuously executed. On the other hand, when the release signal is output (S11: Yes), the control flag is turned OFF (S12). Thereby, the rotational speed control by the motor control unit 33 is released. Then, with the cancellation of the rotational speed control, the control timer is stopped (S13), reset, and the process ends.

<Effect>
As described above, the hybrid control unit 31 as the sudden braking determination unit determines whether the vehicle is suddenly braked in a state where the drive motor 20 is connected to the output shaft of the engine 10. At this time, the drive motor 20 is directly connected to the drive wheel 4 of the vehicle or indirectly connected via the output shaft of the engine 10. Therefore, the drive control device 2 can detect the rotation speed of the drive wheel 4 by detecting the rotation speed of the drive motor 20 with the motor rotation speed sensor 23 serving as detection means. That is, the amount of change in the rotational speed of the drive wheel 4 can be detected based on the amount of change in the rotational speed of the drive motor 20 obtained from the rotational speed of the drive motor 20 detected within a predetermined period. Therefore, it is possible to determine the sudden braking of the vehicle based on the amount of change in the rotational speed of the drive motor 20.

  Further, a sensor such as an encoder or a resolver is used as the motor rotation speed sensor 23. Since such a motor rotational speed sensor 23 has a higher resolution than a sensor that directly detects the rotational speed of the drive wheel, the rotational position and rotational speed of the drive motor 20 can be detected with high accuracy. Thereby, compared with the case where the rotation speed of a drive wheel is detected, the variation | change_quantity of the rotation speed of the drive wheel 4 can be detected more accurately. Therefore, the hybrid control unit 31 can determine sudden braking of the vehicle with higher accuracy based on the amount of change in the rotational speed of the drive motor 20 (that is, the amount of change in the rotational speed of the drive wheels 4). Further, in the present embodiment, the hybrid control unit 31 determines the sudden braking of the vehicle based on the amount of change ΔR of the rotational speed of the drive motor 20 during the predetermined period ΔT. As a result, sudden braking when the vehicle is traveling at low speed can be detected immediately and with higher accuracy.

  Further, the motor control unit 33 which is a rotation speed control means controls the rotation speed of the drive motor 20 so as to drive the drive motor 20 based on the determination result of the hybrid control unit 31 and to apply a driving force to the engine 10. . Thereby, the motor control unit 33 rotates the drive motor 20 connected to the output shaft of the engine 10 so that the rotation speed of the engine 10 does not fall below the lower limit rotation speed when the vehicle is suddenly braked. Perform number control. As described above, the motor control unit 33 can appropriately control the rotational speed of the drive motor 20 because the motor control unit 33 is based on the sudden braking of the vehicle determined by the hybrid control unit 31 with high accuracy. Therefore, when the vehicle is suddenly braked and the drive wheels 4 are locked or close to the lock, and the rotation speed of the drive wheels 4 is suddenly reduced, the engine 10 can be reliably prevented from stalling.

  Further, the motor control unit 33 is configured to feedback control the drive motor 20 based on the amount of change in the rotation speed of the drive motor 20. Thereby, in a state where the rotation speed of the drive motor 20 is controlled by the motor control unit 33, the rotation speed of the engine 10 is larger than the lower limit rotation speed, and a predetermined rotation near the rotation speed when the engine 10 is idling. Controlled to fit between numbers. Therefore, the stall of the engine 10 can be prevented without affecting the braking distance of the vehicle. The hybrid control unit 31 also functions as a release determination unit that determines whether to release the rotation speed control by the motor control unit 33 based on the vehicle information. As a result, the drive control device 2 can properly cancel the rotational speed control of the drive motor 20 by the hybrid control unit 31, so that it is possible to prevent a load from being applied to the engine 10 and the drive wheels 4.

<Modification of Embodiment>
In the present embodiment, the hybrid control unit 31 determines sudden braking based on the change amount ΔR of the motor rotation number as the change amount of the rotation number of the drive motor 20. On the other hand, sudden braking may be determined based on the amount of change in the rotational speed of the drive motor 20 and the control signal for ABS control. The ABS control prevents the driving wheels 4 from being locked when the vehicle is braked, and is executed based on a control signal output from the vehicle. Therefore, the hybrid control unit 31 can more accurately determine that the sudden braking has been applied to the vehicle by determining the sudden braking of the vehicle based on the control signal of the ABS control. Therefore, stalling of the engine 10 can be prevented more reliably.

  In addition, in this embodiment, the drive motor 20 was demonstrated as what is a drive source of the hybrid type vehicle 1. FIG. On the other hand, the rotating electrical machine of the drive control device 2 can be connected to the drive wheels 4 as long as it can assist the rotation of the engine 10 via the output shaft of the engine 10. For example, in the case of a two-motor hybrid vehicle including a drive motor and a generator, power may be supplied to a generator that is connected to the engine 10 and functions as a generator, and a driving force may be applied to the engine 10 during sudden braking. . Similar effects can be obtained with such a configuration.

DESCRIPTION OF SYMBOLS 1: Hybrid type vehicle 2: Drive control apparatus 3: Sensor 4: Drive wheel 10: Engine (internal combustion engine) 11: Planetary gear unit 12: Transmission 20: Drive motor (rotary electric machine) 21: Inverter 22: Battery 23: Motor rotation speed sensor (detection means)
30: ECU, 31: Hybrid control unit (rapid braking determination means)
32: Engine control unit, 33: Motor control unit (rotational speed control means)
34: Transmission control unit, 35: ABS control unit

Claims (4)

An internal combustion engine having an output shaft connectable to drive wheels of the vehicle;
A rotating electric machine connectable to the drive wheel;
Detection means provided in the rotating electrical machine for detecting the rotational speed of the rotating electrical machine;
In a state in which the rotating electrical machine is connected to the output shaft of the internal combustion engine, the sudden braking of the vehicle is determined based on the amount of change in the rotational speed of the rotating electrical machine detected by the detection means within a predetermined period. Sudden braking determination means;
In order to maintain the rotational speed of the internal combustion engine higher than the lower limit rotational speed capable of preventing the stall of the internal combustion engine, the rotating electrical machine is driven based on the determination result of the sudden braking determination means. A rotational speed control means for controlling the rotational speed of the rotating electrical machine so as to apply a driving force to the internal combustion engine;
A vehicle drive control device comprising: In claim 1,
The sudden braking determination means determines sudden braking of the vehicle based on the amount of change in the rotational speed of the rotating electrical machine detected by the detection means and a control signal for antilock brake control of the vehicle. A vehicle drive control device. In claim 1 or 2,
The rotational speed control means controls the rotational speed of the rotating electrical machine so as to apply a driving force to the internal combustion engine, so that the rotational speed of the internal combustion engine is near the rotational speed at idling from the lower limit rotational speed. A drive control apparatus for a vehicle, wherein feedback control of the rotating electrical machine is performed based on the rotational speed of the rotating electrical machine so that the rotational speed is between the predetermined rotational speed and a predetermined rotational speed. In any one of Claims 1-3,
In a state where the rotational speed control means controls the rotational speed of the rotating electrical machine so as to apply driving force to the internal combustion engine, the vehicle speed of the vehicle, the rotational speed of the internal combustion engine, and the antilock brake of the vehicle The vehicle drive control apparatus further comprising: a release determination unit that determines whether to cancel the control of the rotational speed of the rotating electrical machine by the rotational speed control unit based on at least one of control signals. .

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