JP5870257B2 - Vehicle drive device - Google Patents

Description

  The present invention relates to a vehicle drive device having a fuel cut function.

  Conventionally, a vehicle drive device having a function of performing fuel cut at the time of deceleration has been widely used. FIG. 5 shows a configuration diagram of a fuel cut control device in such a vehicle drive device.

  In FIG. 5, the fuel cut control device includes a fuel supply control unit 101 that controls fuel supply to the internal combustion engine, and a fuel cut control unit 102, and further includes a deceleration operation state detection unit 103 and a hysteresis change unit 104. It has. The fuel cut control means 102 generates a fuel cut signal when the engine speed exceeds a first predetermined value in the deceleration operation state, and the second predetermined value on the lower rotation side than the first predetermined value. When it falls below the value, a fuel return signal for restarting the fuel supply is generated. When there is a fuel cut signal, the fuel is cut, and the fuel supply is recovered by the fuel return signal. The deceleration operation state detection means 103 detects a deceleration operation state in which the downhill gradient changes. The hysteresis changing means 104 changes the difference between the first predetermined value and the second predetermined value in accordance with the change in gradient.

  As a result, when driving on a downhill road where the slope gradually becomes steeper by gradually updating the fuel cut speed to the increasing side at each fuel cut, the fuel cut is performed each time the slope changes. Therefore, the prevention of hunting and the improvement of fuel consumption efficiency can be harmonized.

Japanese Patent Laid-Open No. 5-280394

  According to a conventional fuel cut control device, it is described that fuel can be cut every time the slope changes in traveling on a downhill road, and hunting prevention and improvement of fuel consumption efficiency can be harmonized. However, it is also described that when the engine speed (corresponding to the vehicle speed) falls below the fuel-cut return speed, the fuel supply state is restored. This is because if the engine speed falls below the fuel cut return speed, the engine cannot be restarted and the possibility of engine stall increases. At this time, since the braking force suddenly changes when the vehicle approaches a steep uphill, in order to suppress engine stall even in such a situation, the return rotational speed has to be set high. As a result, the fuel supply is recovered and the engine is restarted even in areas where the engine stall does not occur even if the return speed is set low, such as when driving on a flat road. There was a problem that it could not be obtained.

  Furthermore, a crank angle sensor and a wheel speed sensor used for a general vehicle for detecting the engine rotational speed correspond to the rotational speed by changing the distance between the unevenness of the gear and the coil from the viewpoint of in-vehicle durability. Although the number of revolutions and the vehicle speed are detected by outputting a pulse, it is difficult to increase the accuracy in principle because of the gear pitch. For this reason, an error is included in the engine speed that is a criterion for performing engine restart. Therefore, it is necessary to set the return rotational speed higher by the amount of the error, and there is a problem that a sufficient fuel efficiency improvement effect by fuel cut cannot be obtained from this aspect.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a vehicle drive device that can obtain more fuel consumption improvement effects in a vehicle having a fuel cut function.

In order to solve the above-described conventional problems, a vehicle drive device according to the present invention is a vehicle drive device for a vehicle that performs fuel cut during deceleration, and is capable of powering and regeneration connected to an axle of the vehicle. A motor, an inverter electrically connected to the motor and controlling the power running and the regeneration, a rotation speed detection means for detecting a rotation speed (rn) of the motor, the inverter, the rotation speed detection means and the electric Control means for the vehicle connected to each other. The control means detects the rotational speed (rn) obtained from the rotational speed detection means at the time of deceleration , and subtracts the rotational speed (rn) from 1 by dividing the rotational speed (rn) by the previous rotational speed (rn-1). If the deceleration obtained in step (Δr = 1−rn / rn−1) is equal to or less than a predetermined allowable deceleration (Δrs), the regeneration is performed by the motor and the fuel cut during deceleration is performed. On the other hand, if the deceleration (Δr) becomes larger than the allowable deceleration (Δrs), the motor is moved from the regeneration to the power running so that the deceleration (Δr) becomes the allowable deceleration (Δrs). At the same time, the fuel cut during deceleration is stopped, and the power running of the motor is stopped when a stop condition of the motor, which is a state where the engine restart of the vehicle is completed, is satisfied.

  The rotational speed detection means may be a resolver.

  The control circuit determines that the stop condition of the motor is not satisfied when deceleration continues despite the driver's depression of the accelerator pedal, and further determines the amount of depression of the accelerator pedal. The power running of the motor may be continued.

  The vehicle further includes another motor connected to the axle or another axle, the other motor is electrically connected to the control means, and the control means removes the motor from the regeneration. When switching to the power running, the other motor may be regenerated.

In the vehicle drive device of the present invention, the rotational speed (r _n ) of the motor is detected by the rotational speed detection means, so that the vehicle speed can be detected with higher accuracy than conventional crank angle sensors and wheel speed sensors. In addition, since the motor response is faster than that of the engine, it can be controlled at high speed. As a result, it is possible to increase the fuel cut region by reducing the necessity of restarting the engine earlier as much as the conventional vehicle speed error is expected.

Further, if the deceleration (Δr) becomes larger than the allowable deceleration (Δr _s ), such as when the vehicle approaches a steep slope during deceleration, the motor that has been regenerated is immediately powered and decelerated. Stop the fuel cut. As a result, the engine can be restarted even in the expanded fuel cut region, and the possibility of engine stall can be reduced.

In the above case, since the motor is switched from regeneration to power running so that the deceleration (Δr) becomes an allowable deceleration (Δr _s ), power consumption due to unnecessary power running is suppressed and a rapid decrease is achieved. Since the change in the speed (Δr) can be reduced, the possibility of impairing the driver's feeling of deceleration can also be reduced.

  From these facts, it is possible to widen the fuel cut region and reduce unnecessary power running so as to reduce the possibility of engine stall by means of highly accurate rotation speed detection means. There is an effect that a vehicle drive device capable of obtaining a fuel efficiency improvement effect can be obtained.

1 is a schematic configuration diagram of a vehicle drive device according to Embodiment 1 of the present invention. FIG. 2 is a time-dependent characteristic diagram at the vehicle speed of a vehicle using the vehicle drive device according to the first embodiment of the present invention, (a) is a time-dependent characteristic diagram at the vehicle speed of a conventional vehicle, and (b) is a rotational speed detection means in the vehicle of the present application. (C) is a time-dependent characteristic diagram of vehicle speed when traveling on a flat road, and (c) is a time-dependent characteristic diagram of vehicle speed when traveling on a steep uphill while decelerating using the rotational speed detecting means in the vehicle of the present application. ) Is an enlarged view of a broken-line circle portion in FIG. The flowchart which shows the operation | movement at the time of the steep uphill driving during deceleration when using the rotation speed detection means of the vehicle drive device in Embodiment 1 of this invention. The flowchart which shows the operation | movement at the time of a steep uphill driving during deceleration when using the rotation speed detection means of the vehicle drive device in Embodiment 3 of this invention. Configuration diagram of conventional fuel cut control device

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a vehicle drive device according to Embodiment 1 of the present invention. FIG. 2 is a time-dependent characteristic diagram at a vehicle speed of a vehicle using the vehicle drive device according to the first embodiment of the present invention. FIG. FIG. 5C is a time-dependent characteristic diagram of vehicle speed when traveling on a flat road when using the rotational speed detecting means, and FIG. 5C is a time-dependent characteristic of vehicle speed when traveling steeply uphill during deceleration when using the rotational speed detecting means of the vehicle of the present application. FIG. 4D is an enlarged view of a broken-line circle portion in FIG. FIG. 3 is a flowchart showing an operation at the time of steep climbing while decelerating when the rotational speed detection means of the vehicle drive device in Embodiment 1 of the present invention is used.

In FIG. 1, a vehicle drive device 1 is mounted on a vehicle that performs fuel cut during deceleration, and is connected to an axle 11 of the vehicle and capable of powering and regenerating, the motor The inverter 14 that is electrically connected and controls the power running and the regeneration, the rotation speed detection means 15 that detects the rotation speed rn of the motor 13, and the inverter 14 and the rotation speed detection means 15 that are electrically connected. Vehicle control means 17. Then, the control means 17 detects the rotational speed rn obtained from the rotational speed detection means 15 at the time of deceleration , and decelerates the rotational speed rn by the previous rotational speed rn−1 and subtracts it from 1 to obtain a deceleration Δr ( = 1−rn / rn−1) is equal to or less than a predetermined allowable deceleration Δrs, the motor 13 performs the regeneration and the deceleration fuel cut. On the other hand, if the deceleration Δr becomes larger than the allowable deceleration Δrs, the motor 13 is switched from the regeneration to the power running so that the deceleration Δr becomes the allowable deceleration Δrs, and the fuel cut at deceleration is stopped. When the stop condition of the motor 13 in a state where the engine restart of the vehicle is completed, the power running of the motor 13 is stopped.

  As a result, the fuel cut area can be widened with high-accuracy rotational speed detection means and the possibility of engine stall is reduced, and unnecessary power running is also suppressed, resulting in more fuel efficiency improvement. A vehicle drive device capable of obtaining the effect is obtained.

  Hereinafter, the configuration and operation of the present embodiment will be described more specifically.

  In FIG. 1, an engine 23 is mounted on a vehicle body 21 of a vehicle for driving the vehicle. In the first embodiment, the engine 23 is mounted on the front portion of the vehicle body 21 and drives the front wheels. Therefore, the vehicle is an FF (front engine, front drive) vehicle. Since the configuration for driving the front wheels by the engine 23 is the same as that of a general FF vehicle, a detailed description thereof is omitted.

  On the other hand, a motor 13 is connected to the axle 11 on the rear wheel side of the vehicle body 21. Here, the motor 13 drives the axle 11 and generates power by being rotated by the axle 11 when the vehicle is decelerated. Therefore, the motor 13 has a configuration capable of power running and regeneration.

A rotation speed detecting means 15 is attached to the motor 13. In the first embodiment, a resolver is used as the rotation speed detection means 15. Since the rotation speed detecting means 15 (resolver) are those from the two-phase AC voltage for detecting a rotational speed r _n of the motor 13, as the crank angle sensor and wheel speed sensors described above, the accuracy affects the pitch of the gear The angle output is possible in an analog manner. As a result, it is possible to detect the rotational speed r _n with high accuracy. In addition, since the resolver has a simple structure in which the basic structure is composed of, for example, two sets of coils and an iron core, it is possible to obtain in-vehicle durability.

The rotational speed detection means 15 is not limited to a resolver, and may have the same principle or another principle such as an optical encoder. Further, the invention is not limited to the configuration of attaching the resolver separately motor 13 may be for example a sensorless configuration the motor 13 detects the rotational speed r _n based on the voltage generated during regenerative. In this case, the rotation speed detection means 15 is included in the motor 13.

In addition, the motor 13 and the axle 11 are connected via a transmission gear (not shown), the gear ratio is set such that the rotational speed r _n of the motor 13 relative to the axle 11 increases. Therefore, the rotation speed r _n of the motor 13 becomes larger than the rotational speed of the axle 11, the measurement range of the rotational speed r _n is an enlarged, the motor 13 correspondingly, for example, conventional wheel speed sensor as a rotating speed detecting means 15 Even if it is attached to, the required accuracy can be obtained depending on the gear ratio. Therefore, it is also possible to detect the rotational speed r _n This configuration.

  An inverter 14 is electrically connected to the motor 13. In addition, a high voltage battery 27 is electrically connected to the inverter 14. Therefore, the regenerative power generated by the motor 13 is charged to the high voltage battery 27 by the inverter 14. Furthermore, the power running operation of the motor 13 is performed via the inverter 14 by the electric power of the high voltage battery 27. The high voltage battery 27 is a lithium ion battery having a rated charging voltage of 48V, for example. The high voltage battery 27 is electrically connected to a high voltage load 29 that can be driven at 48V. The high-voltage load 29 is a load that mainly consumes a large amount of power, such as an electric power steering.

  The high voltage battery 27 is further electrically connected to the low voltage battery 33 via the DC / DC converter 31. The low voltage battery 33 is a lead battery having a low voltage of 12V.

  Note that a low voltage load 35 is electrically connected to the low voltage battery 33. The low-voltage load 35 has lower power consumption than the high-voltage load 29. A starter 37 and an alternator 39 are electrically connected to the low voltage battery 33. These configurations are the same as those of a general vehicle.

  With such a configuration, for example, the power of the high voltage battery 27 can be supplied to the low voltage battery 33 and the low voltage load 35 by the DC / DC converter 31. Moreover, it is good also as a structure which can perform reverse operation | movement. Furthermore, by making the DC / DC converter 31 a bidirectional type, high-voltage power and low-voltage power can be freely exchanged. As described above, since the exchange of electric power can be controlled by the configuration of the DC / DC converter 31, the DC / DC converter 31 having a necessary function may be used.

  In the case where it is not necessary to exchange the high-voltage power and the low-voltage power, the DC / DC converter 31 may be omitted, and the respective power systems may be independent.

The inverter 14 and the rotation speed detection means 15 are electrically connected to the control means 17. Control means 17 is constituted by a peripheral circuit such as a microcomputer and a memory, and detect the rotational speed r _n of the motor 13 from the rotation speed detecting means 15, the power running of the motor 13 by controlling the inverter 14, or perform regeneration . In addition to the above, the control means 17 performs overall control of the vehicle body 21, and is connected to various electrical components such as the engine 23, the starter 37, and the alternator 39, for example.

  Next, operation | movement of such a vehicle drive device 1 is demonstrated in detail using FIG. 2, FIG.

  First, FIG. 2 shows a change over time in the vehicle speed until the vehicle travels in the order of acceleration, constant speed, and deceleration from the stop state until it stops again. FIG. 2A shows a change with time of a conventional vehicle (FF vehicle) in which the motor 13 is not mounted. The vehicle speed is 0 from time t0 to time t10. Acceleration starts at time t10. At this time, the engine 23 performs fuel injection for traveling.

  Next, when the vehicle speed V1 is reached at time t20, the vehicle travels at a constant speed. Also in this case, the engine 23 continues fuel injection.

  Next, when the vehicle decelerates at time t30, the control means 17 controls the engine 23 to perform fuel cut. As a result, fuel can be saved.

  Next, when the vehicle speed is reduced to the vehicle speed V <b> 2 at time t <b> 40, the control unit 17 stops the fuel cut for the engine 23. That is, fuel injection is performed again after time t40. The rotational speed of the engine 23 corresponding to the vehicle speed V2 has a margin in order to ensure the detection error of the rotational speed and the minimum rotational speed to prevent engine stall at the time of sudden climbing. The vehicle speed is set to be high.

  When the vehicle stops at time t80, idling stop is performed thereafter, and the fuel cut state is entered again.

  The above is the operation in the conventional vehicle. First, the operation in the first embodiment will be described with reference to FIG. In FIG. 2 (b), the vehicle is traveling on a flat road.

From time t0 to time t30 is the same as FIG. When deceleration starts at time t <b> 30, the control unit 17 starts fuel cut and controls the inverter 14 to take out regenerative power by the motor 13 and charge the high voltage battery 27. And if it is the conventional vehicle, even if it reaches vehicle speed V2 which restarts fuel injection, a fuel cut state is maintained. Thereafter, fuel injection is started at a vehicle speed V3 that is lower than the vehicle speed V2. Therefore, as shown by the white arrow in FIG. 2B, the fuel cut region can be expanded during the period from time t40 to time t70. This, in the first embodiment, employs a rotational speed detecting means 15 capable of detecting the rotational speed r _n of the motor 13 from the two-phase AC voltage with high accuracy, in consideration of an error of the rotational speed r _n This is because the vehicle speed at which fuel injection is resumed can be set low.

  When reaching time t70, the control means 17 restarts the fuel injection and restarts the engine 23. The subsequent operation after time t80 is the same as that in FIG.

  Next, a case where the vehicle is traveling on a road including a steep climb in the first embodiment will be described with reference to FIGS. From time t0 to time t30 is the same as FIG. When deceleration starts at time t30, the control means 17 starts fuel cut and takes out the regenerative power as described above. Then, the control means 17 performs control so that the fuel cut is continued until the vehicle speed reaches the vehicle speed V3. However, it is assumed that a steep climb is reached at the time t50 on the way. At this time, since the vehicle decelerates rapidly, the vehicle speed from time t50 to time t60 in FIG. 2 (d) is shown so far (from vehicle speed V2 to vehicle speed V21) as indicated by vehicle speed V21 to vehicle speed V22, respectively. Compared to this, the vehicle speed suddenly decreases. That is, the deceleration Δr increases.

Here, the deceleration Δr is defined as follows. Control means 17 detects from the output of the speed detecting means 15 the rotational speed r _n of the motor 13 corresponding to the vehicle speed for each predetermined period (e.g., 0.1 seconds). Therefore, by using the rotational speed r _n detected this time and the previous rotational speed r _n-1 previously detected,
Δr = 1−r _n / r _n−1 (1)
Is defined as obtaining the deceleration Δr. Therefore, the deceleration Δr increases if the vehicle is suddenly decelerated.

The control means 17 obtains the deceleration Δr by the equation (1) and compares it with a predetermined allowable deceleration Δr _s determined in advance. Here, the allowable deceleration Δr _s is defined as a value at which the engine cannot be restarted when the deceleration Δr becomes larger than this. Here, the deceleration [Delta] r determined by the time t50 to the time t60 is greater than the allowable deceleration [Delta] r _s. In this case, it is necessary to restart the engine immediately. However, since the deceleration Δr is large, there is a high possibility that the engine cannot be restarted as it is. Therefore, the control means 17 controls the inverter 14 so as to immediately switch the motor 13 from regeneration to power running, and drives the vehicle so that the deceleration Δr _s becomes the allowable deceleration Δrs that can restart the engine. . Furthermore, the process for fuel injection is resumed. Thereby, as shown from time t60 to time t65 in FIG. 2D, it can be seen that the change in the vehicle speed from the vehicle speed V22 to the vehicle speed V23 is suppressed, and the deceleration Δr becomes small. In this state, the control means 17 restarts the engine at time t65. And if engine restart is completed, the power running of the motor 13 will be stopped. Since the engine 23 is rotating at the time t65, the engine 23 is in a state where it can be pushed. Therefore, the engine can be restarted by specifically injecting fuel and igniting, and the starter 37 need not be started.

  With the above operation, the engine restart is completed after time t65 in FIG. 2D, and thereafter, the engine 23 is driven even on an uphill road, so the possibility of engine stall is reduced. Thereafter, the operation after time t80 is the same as that shown in FIG.

The operations shown in FIGS. 2C and 2D are summarized as follows. Control means 17, the deceleration [Delta] r and the like approaches the steep uphill road during deceleration exceeds the allowable deceleration [Delta] r _s, even fuel cut enlarged region to reduce the possibility of engine stalling to immediately controls the motor 13 from the regeneration to power running, so deceleration [Delta] r is allowable deceleration [Delta] r _s. Then, the fuel injection process is restarted and the engine is restarted. Thereafter, the power running of the motor 13 is stopped.

Such control while reducing the possibility of the engine stall, upon which can be expanded as much as possible the fuel cut region, the switches the motor to the deceleration [Delta] r is allowable deceleration [Delta] r _s power running from the regenerative Since power consumption due to unnecessary power running is suppressed, more fuel efficiency improvement effects can be obtained.

Further, by switching the motor from regeneration to power running so that the deceleration Δr becomes the allowable deceleration Δr _s , the rapid change in the deceleration Δr can be reduced, so that the driver may feel a sense of deceleration. Performance can be reduced, and driving with less discomfort is possible.

  Next, the operation at the time of deceleration at the vehicle speed V3 or higher will be described with reference to the flowchart of FIG. At this time, the motor 13 is performing regeneration. 3 is a subroutine executed periodically (for example, every 0.1 second) from a main routine (not shown) of the microcomputer.

When the subroutine of FIG. 3 is executed, the control unit 17 detects the rotational speed r _n from the output of the speed detecting means 15 (step number S1). Next, the control means 17 calculates the deceleration Δr with respect to the previous rotational speed r _n−1 stored in the memory by the equation (1) (S2).

Next, the control unit 17 compares the deceleration [Delta] r and acceptable deceleration Δr _s (S3). Here, the allowable deceleration [Delta] r _s is stored in advance in the memory.

If any deceleration [Delta] r is less acceptable deceleration Δr _s (S3 No) of, because is not approaching a steep uphill road, the control unit 17 performs the operation after S8 to be described later.

On the other hand, is larger than the deceleration [Delta] r is allowable deceleration Δr _s (S3 Yes in), the control unit 17 determines that the approaching a steep uphill road, immediately switch the motor 13 from the regeneration to power running (S4) . Thereafter, by performing fuel injection (S5), the engine is restarted.

  Next, it is determined whether or not a motor stop condition is satisfied (S6). In the first embodiment, the motor stop condition is defined as a state where the engine restart is completed. If the motor stop condition is not satisfied (No in S6), since the engine 23 has not been restarted, the control unit 17 returns to S6 and waits until the restart is completed.

On the other hand, if the motor stop condition is satisfied (Yes in S6), the control means 17 stops the motor 13 (S7). Then, stored in the memory a rotational speed r _n detected at step S1 as the previous rotation speed r _n-1 (S8). Thereafter, the subroutine of FIG. 3 is terminated and the process returns to the main routine.

With the above-described structure and operation, the vehicle drive device 1, since the detected rotational speed r _n by the rotation speed detecting means 15 for detecting a rotational speed r _n of the motor 13 from the two-phase AC voltage, high accuracy of the vehicle speed Can be detected. As a result, it is possible to increase the fuel cut region by reducing the necessity of restarting the engine earlier as much as the conventional vehicle speed error is expected.

Further, during deceleration, such as when the vehicle is approaching a steep uphill road, the larger than its deceleration [Delta] r is allowable deceleration [Delta] r _s, and powering the motor 13 which has been regenerated immediately the deceleration fuel cut Discontinue. As a result, even in the expanded fuel cut region, the engine can be restarted and the possibility of engine stall can be reduced.

Further, in the case described above, the switching between the motor 13 as deceleration [Delta] r is allowable deceleration [Delta] r _s power running from the regenerative, with power consumption due to unnecessary power running is suppressed, the rapid deceleration [Delta] r Since the change can be reduced, the possibility of impairing the driver's feeling of deceleration can also be reduced.

  From these facts, it is possible to widen the fuel cut region and reduce unnecessary power running so as to reduce the possibility of engine stall by means of highly accurate rotation speed detection means. The vehicle drive device 1 capable of obtaining the fuel efficiency improvement effect is obtained.

  In the first embodiment, the motor 13 is connected to the axle 11. However, the motor 13 may be connected to another axle 41 (here, the front axle).

(Embodiment 2)
Since the configuration of the second embodiment is the same as that of the first embodiment, the operation that characterizes the second embodiment will be described.

  In other words, the operation that characterizes the second embodiment is that when the control means 17 continues to decelerate despite the driver depressing an accelerator pedal (not shown), the stop condition of the motor 13 is satisfied. It is determined that the motor 13 is not running, and the power running of the motor 13 is continued according to the further depression amount of the accelerator pedal.

  As a result, even when the uphill road continues, the motor 13 continues powering accordingly, so that the fuel consumption of the engine 23 can be suppressed.

  The detailed operation will be described below.

  When the vehicle is decelerating and the vehicle speed is equal to or higher than the vehicle speed V3 described in the first embodiment, the control means 17 periodically executes the subroutine of FIG. Here, in the case of the second embodiment, first, operations from S1 to S5 in the subroutine of FIG. 3 are the same as those in the first embodiment. The operation in the case of No in S3 is the same as that in the first embodiment.

  In S6 of FIG. 3, the control means 17 is based on whether or not the deceleration is continued despite the depression of the accelerator pedal by the driver, in addition to the completion of the engine restart as the motor stop condition. That is, when the driver depresses the accelerator pedal and the vehicle accelerates on an uphill road, the vehicle is traveling as intended by the driver, and therefore the motor stop condition is defined to be satisfied. Conversely, if the driver continues to decelerate even when the accelerator pedal is depressed, the vehicle is decelerating against the driver's intention, which gives the driver a great sense of discomfort. Therefore, the control means 17 determines that the motor stop condition is not satisfied in this case, and continues the power running. Therefore, in S6 of FIG. 3, if the engine 23 has already been restarted and the driver depresses the accelerator pedal and the vehicle accelerates, the vehicle climbs up according to the driver's intention. Therefore, the motor stop condition is satisfied (Yes in S6).

  On the other hand, if the engine 23 has not yet been restarted or if the vehicle continues to decelerate even when the driver depresses the accelerator pedal, the motor stop condition is not satisfied (No in S6).

  Whether the vehicle is accelerating or decelerating can be obtained from the deceleration Δr. That is, if the deceleration Δr is positive, it is decelerated, and if it is negative, it is acceleration. In addition to this method, it may be determined whether the vehicle is decelerating or accelerating by referring to a change in a general vehicle speed signal.

  By controlling as described above, when sufficient acceleration cannot be obtained even when climbing only with the engine 23, the load on the engine 23 can be reduced by powering the motor 13, which leads to improved fuel efficiency. Furthermore, it is possible to reduce a sense of discomfort to the driver.

(Embodiment 3)
FIG. 4 is a flowchart showing an operation at the time of steep climbing while decelerating when the rotational speed detection means of the vehicle drive device according to Embodiment 3 of the present invention is used.

  In the configuration of the vehicle drive device 1 in the third embodiment, the same parts as those in FIG. 1 of the first embodiment are denoted by the same reference numerals, and only the characteristic parts will be described.

  That is, in FIG. 1, the vehicle drive device 1 according to the third embodiment further includes another motor connected to the axle 11 or another axle 41, and the other motor is electrically connected to the control means 17. It is connected.

  This detailed configuration will be described. Since the motor 13 is already connected to the axle 11, in the third embodiment, another motor, that is, an alternator 39 is further connected to the other axle 41. Here, since the alternator 39 is a generator and has the same configuration as the motor, it is defined here that the alternator 39 is used as another motor. 1, the alternator 39 is not directly connected to the other axle 41, but is connected via the engine 23. In this case, it is defined that the alternator 39 is connected to the other axle 41.

  Next, a characteristic part of the operation of the vehicle drive device 1 having such a configuration will be described. The control means 17 controls the other motor (alternator 39) to regenerate when the motor 13 is switched from regeneration to power running. Thereby, the vehicle speed peak at the time of engine restart after the time t65 of FIG.2 (d) can be reduced.

  Details of this operation will be described with reference to FIG. In FIG. 4, the same operations as those in FIG. 3 are denoted by the same step numbers, and detailed description thereof is omitted.

  First, S1 to S4 in FIG. 4 are the same as those in FIG. Note that the operation in the case of No in S3 is the same as in FIG.

  In S4 of FIG. 4, since the motor 13 is controlled by power running, the engine is being restarted. At this time, the control means 17 controls the other motor (alternator 39) to perform regeneration. Specifically, the control means 17 adjusts the field current of the alternator 39. Next, the control means 17 performs fuel injection (S5) and restarts the engine.

  With this series of operations, in the first embodiment, as shown in FIG. 2D, after the time t65, there is a peak of the vehicle speed for a moment, and the vehicle is accelerated. 3, since the alternator 39 is controlled to regenerate as much as the vehicle is about to accelerate, the acceleration can be offset. As a result, electric power corresponding to the energy for acceleration can be recovered by the alternator 39 and charged to the low voltage battery 33. Furthermore, it is possible to suppress the operation of the vehicle, which is very uncomfortable for the driver, such that the vehicle being decelerated accelerates for a moment.

  Next, if the motor stop condition is satisfied (Yes in S6), the control means 17 stops not only the motor 13 but also other motors (S12). The subsequent operation is the same as in FIG.

  Although the operation of the other motor is stopped in S12, this is because the alternator 39 is used as the other motor in the third embodiment. Alternatively, power generation may be continued.

  With the above-described configuration and operation, it is possible to improve fuel efficiency by regenerating energy for the vehicle speed peak, and it is possible to suppress the operation of the vehicle, which is very uncomfortable for the driver, such as instantaneous acceleration during deceleration. The vehicle drive device 1 is obtained.

  In the third embodiment, the alternator 39 is used as another motor. However, the present invention is not limited to this, and the other motor may be provided separately from the alternator 39.

  In the third embodiment, the motor 13 is disposed on the axle 11 and the other motor (alternator 39) is disposed on the other axle 41. However, the present invention is not limited thereto. A configuration in which the other motor is reversed may be employed, or a configuration in which both the motor 13 and the other motor are connected to one axle may be employed.

  Since the vehicle drive device according to the present invention can obtain more fuel efficiency improvement effects, it is particularly useful as a vehicle drive device having a fuel cut function.

DESCRIPTION OF SYMBOLS 1 Vehicle drive device 11 Axle 13 Motor 14 Inverter 15 Rotational speed detection means 17 Control means 39 Alternator (other motor)
41 Other axles

Claims (4)

A vehicle drive device for a vehicle that performs fuel cut during deceleration,
A motor capable of power running and regeneration connected to the axle of the vehicle;
An inverter electrically connected to the motor and controlling the power running and the regeneration;
A rotational speed detection means for detecting the rotational speed (rn) of the motor;
Control means for the vehicle electrically connected to the inverter and the rotation speed detection means,
The control means detects the rotational speed (rn) obtained from the rotational speed detection means during deceleration ,
The deceleration (Δr = 1−rn / rn−1) obtained by dividing the rotational speed (rn) by the previous rotational speed (rn−1) and subtracting from 1 is equal to or less than a predetermined allowable deceleration (Δrs). Then, while performing the regeneration by the motor, performing the fuel cut at the time of deceleration,
When the deceleration (Δr) becomes larger than the allowable deceleration (Δrs), the motor is switched from the regeneration to the power running so that the deceleration (Δr) becomes the allowable deceleration (Δrs). The vehicle drive device which stops the power running of the motor when the motor stop condition is satisfied, in which the fuel cut at deceleration is stopped and the engine restart of the vehicle is completed . The vehicle drive device according to claim 1, wherein the rotational speed detection means is a resolver. The control means determines that the stop condition of the motor is not satisfied when deceleration continues despite the driver's depression of the accelerator pedal, and according to the further depression amount of the accelerator pedal, The vehicle drive device according to claim 1, wherein the power running of the motor is continued. The vehicle further includes another motor connected to the axle or another axle,
The other motor is electrically connected to the control means;
The vehicle drive device according to claim 1, wherein the control unit regenerates the other motor when the motor is switched from the regeneration to the power running.

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