JP2014139035A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately control an electric oil pump on an uphill road.SOLUTION: A vehicle control device including a drive source and drive wheels driven by the drive source, comprises: a hydraulic actuation mechanism provided on a power transmission path between the drive source and the drive wheels; an electric oil pump for supplying a working fluid to the hydraulic actuation mechanism; and a pump control unit for controlling a discharge pressure of the electric oil pump. The pump control unit executes an output suppression mode (symbol X2) for reducing the discharge pressure of the electric oil pump if a vehicle speed decreases to a reference value by a passenger's brake operation, and cancels the output suppression mode to increase the discharge pressure of the electric oil pump if the drive wheels rotate in an opposite direction to a traveling direction (symbol Y2) while the output suppression mode is being executed.

Description

  The present invention relates to a vehicle control device including a drive source and drive wheels driven by the drive source.

  A hydraulic transmission mechanism such as a hydraulic clutch or a transmission mechanism is provided in a power transmission path between the engine and the drive wheels. Such hydraulic operating mechanisms are often supplied with hydraulic oil from an oil pump driven by an engine. By the way, in an electric vehicle without an engine, a hybrid vehicle that can run while the engine is stopped, an idling stop vehicle that stops the engine when the vehicle is stopped, etc., the hydraulic oil supply state is maintained without being affected by the engine stop. Therefore, an electric oil pump driven by an electric motor is provided.

  In the electric oil pump, the discharge pressure can be freely adjusted by controlling the motor speed and the motor torque. For this reason, a control device has been proposed in which the discharge pressure of the electric oil pump is reduced when the vehicle is stopped, which can reduce the torque capacity of the transmission mechanism or the like (see Patent Document 1). Thereby, the power consumption of the electric oil pump can be suppressed, and the power consumption rate and fuel consumption rate of the vehicle can be improved.

JP 2000-356148 A

  By the way, in the control apparatus of patent document 1, when a passenger | crew's select lever operation etc. are performed, the discharge pressure of an electric oil pump is raised in preparation for re-start. As described above, when the electric oil pump is returned based on the occupant's lever operation or the like, there is a risk of insufficient supply of hydraulic oil to the hydraulic operation mechanism on the uphill road. That is, on the uphill road, there is a possibility that the vehicle may move backward before re-starting, so it has been necessary to supply the hydraulic oil to the hydraulic operation mechanism at a timing earlier than the occupant's lever operation or the like.

  An object of the present invention is to appropriately control an electric oil pump on an uphill road.

  The vehicle control device of the present invention is a vehicle control device including a drive source and drive wheels driven by the drive source, and is a hydraulic operation mechanism provided in a power transmission path between the drive source and the drive wheels. And an electric oil pump that supplies hydraulic oil to the hydraulic operation mechanism, and a pump control unit that controls a discharge pressure of the electric oil pump. An output suppression mode for reducing the discharge pressure of the electric oil pump is reduced when the drive wheel is rotated in the direction opposite to the traveling direction during the execution of the output suppression mode. The output suppression mode is canceled and the discharge pressure of the electric oil pump is increased.

  According to the present invention, when the drive wheel rotates in the direction opposite to the traveling direction during execution of the output suppression mode, the output suppression mode is canceled and the discharge pressure of the electric oil pump is increased. In this way, by increasing the discharge pressure of the electric oil pump without waiting for the occupant's operation, the electric oil pump can be appropriately controlled on the uphill road, and a shortage of hydraulic oil supply to the hydraulic operation mechanism is avoided. It becomes possible.

It is the schematic which shows the control apparatus for vehicles which is one embodiment of this invention. It is a flowchart which shows an example of the control procedure of an electric oil pump. It is a diagram which shows an example of the relationship between a road surface gradient and required discharge pressure. (A) is explanatory drawing which shows the driving state of a vehicle, (b) is a timing chart which shows an example of the execution condition of output suppression mode. (A) is explanatory drawing which shows the driving state of a vehicle, (b) is a timing chart which shows an example of the execution condition of output suppression mode. (A) is explanatory drawing which shows the driving state of a vehicle, (b) is a timing chart which shows an example of the execution condition of output suppression mode.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a vehicle control apparatus 10 according to an embodiment of the present invention. As shown in FIG. 1, the vehicle control device 10 includes an engine 11 and a motor generator 12. A forward / reverse switching mechanism 14 and a continuously variable transmission 15 are provided between the engine 11 and the drive wheels 13. Engine power output from the engine 11 is transmitted to the drive wheels 13 via the forward / reverse switching mechanism 14 and the continuously variable transmission 15. A continuously variable transmission 15 is provided in the power transmission path 16 between the motor generator 12 and the drive wheels 13. Motor power output from the motor generator 12 is transmitted to the drive wheels 13 via the continuously variable transmission 15. The motor generator 12 functions as a drive source and an electric motor.

  The continuously variable transmission 15 has a primary shaft 20 and a secondary shaft 21 parallel to the primary shaft 20. A primary pulley 22 is provided on the primary shaft 20, and a primary oil chamber 23 is defined on the back side of the primary pulley 22. The secondary shaft 21 is provided with a secondary pulley 24, and a secondary oil chamber 25 is defined on the back side of the secondary pulley 24. Further, a drive chain 26 is wound around the primary pulley 22 and the secondary pulley 24. By controlling the supply of hydraulic oil to the primary oil chamber 23 and the secondary oil chamber 25, the pulley groove width can be changed and the winding diameter of the drive chain 26 can be changed. Step shifting is possible. The speed change mechanism is not limited to the chain drive type continuously variable transmission 15, and may be a belt drive type or a traction drive type continuously variable transmission, such as a planetary gear type or parallel shaft type automatic transmission. A transmission may be used.

  A rotor 30 of the motor generator 12 is coupled to the primary shaft 20 of the continuously variable transmission 15. As described above, the continuously variable transmission 15 as a hydraulic operation mechanism is provided between the motor generator 12 and the drive wheels 13, and the motor power is transmitted to the drive wheels 13 via the continuously variable transmission 15. ing. A forward / reverse switching mechanism 14 is provided between the engine 11 and the continuously variable transmission 15. The forward / reverse switching mechanism 14 includes a double pinion planetary gear train 31, a forward clutch 32, and a reverse brake 33. During forward travel using engine power, the forward clutch 32 is engaged and the reverse brake 33 is released, and during reverse travel using engine power, the forward clutch 32 is released and the reverse brake 33 is engaged. Further, when the neutral range (N range) is selected by a select lever (not shown), or when the EV travel mode using only the motor generator 12 as a drive source is set, both the forward clutch 32 and the reverse brake 33 are released. Is done.

  In order to supply hydraulic oil to the continuously variable transmission 15, the forward / reverse switching mechanism 14, etc., the vehicle control device 10 is provided with an electric oil pump 40. Further, in order to control the supply of hydraulic oil discharged from the electric oil pump 40, the vehicle control device 10 is provided with a valve unit 41 in which a plurality of electromagnetic valves are incorporated. The electric oil pump 40 includes an electric motor for driving a pump (not shown), and a battery 43 is connected to the electric oil pump 40 via an inverter 42. By performing energization control on the electric oil pump 40 using the inverter 42, it is possible to control the rotational torque and the rotational speed of the electric oil pump 40. That is, by controlling the drive state of the inverter 42, it is possible to adjust the discharge pressure of the hydraulic oil discharged from the electric oil pump 40. A battery 43 is connected to the stator 44 of the motor generator 12 via an inverter 45. By performing energization control on the motor generator 12 using the inverter 45, the rotational torque and rotational speed of the motor generator 12 can be controlled. Further, a rotation angle sensor 46 such as a resolver for detecting the rotation angle of the rotor 30 is attached to the motor generator 12.

  In order to control the engine 11, the motor generator 12, the continuously variable transmission 15, the electric oil pump 40, and the like, the vehicle control device 10 is provided with a control unit 50. The control unit 50 includes a rotation angle sensor 46, a vehicle speed sensor 51 that detects a traveling speed (vehicle speed) of the vehicle, an accelerator sensor 53 that detects an operation state of the accelerator pedal 52, and a brake that detects an operation state of the brake pedal 54. A sensor 55, an inhibitor switch 56 for detecting the operation state of a select lever (not shown), a road surface gradient sensor 57 such as an acceleration sensor for detecting a road surface gradient, and the like are connected. Then, the control unit 50 determines the vehicle state based on information from various sensors, and outputs a control signal to the engine 11, the valve unit 41, the inverters 42, 45, and the like. That is, the control unit 50 functions as a pump control unit that controls the electric oil pump 40. The control unit 50 includes a CPU that calculates control signals and the like, and also includes a ROM that stores control programs, arithmetic expressions, map data, and the like, and a RAM that temporarily stores data.

  Next, control of the electric oil pump 40 by the control unit 50 will be described. FIG. 2 is a flowchart showing an example of a control procedure of the electric oil pump 40. As shown in FIG. 2, in step S1, it is determined whether or not the vehicle is stopped. In step S1, when the vehicle speed is equal to or lower than a predetermined value (reference value), it is determined that the vehicle is in a stopped state, and when the vehicle speed exceeds a predetermined value, it is determined that the vehicle is in a traveling state. . In addition, as a predetermined value at the time of determining whether it is a stop state, it may be 0 km / h, for example, and may be 10 km / h. If it is determined in step S1 that the vehicle is stopped, the process proceeds to step S2, and it is determined whether or not the brake operation of the occupant is being performed, that is, whether or not the brake pedal 54 is depressed. The If it is determined in step S2 that the brake operation is being performed, the process proceeds to step S3, and the output suppression mode of the electric oil pump 40 is executed, so that the required discharge pressure of the electric oil pump 40 is based on the road surface gradient. Is calculated.

  Here, FIG. 3 is a diagram showing an example of the relationship between the road surface gradient and the required discharge pressure. As shown in FIG. 3, the required discharge pressure is set low when the road gradient is small, while the required discharge pressure is set high when the road gradient is large. In step S3 described above, when the required discharge pressure is set according to the road surface gradient, the process proceeds to step S4, and the discharge pressure of the electric oil pump 40 is controlled toward the required discharge pressure that is the target value. The required discharge pressure set in FIG. 3 is set to be equal to or lower than the lower limit value of the discharge pressure of the electric oil pump 40 during normal travel. That is, in step S4, the output suppression mode for reducing the discharge pressure of the electric oil pump 40 is executed by controlling the discharge pressure of the electric oil pump 40 to the required discharge pressure. In this way, when the vehicle is stopped when the load acting on the continuously variable transmission 15 is reduced, the power suppression of the electric oil pump 40 can be suppressed by executing the output suppression mode of the electric oil pump 40. It becomes possible to improve the fuel consumption of the vehicle.

  Next, conditions for canceling the output suppression mode will be described. In step S5, it is determined whether or not the brake operation of the occupant is released, that is, whether or not the depression of the brake pedal 54 is released. If it is determined in step S5 that the brake operation has been released, the process proceeds to step S6, the output suppression mode is released in preparation for the re-start of the vehicle, and the discharge pressure of the electric oil pump 40 is increased. On the other hand, if it is determined in step S5 that the brake operation has not been released, the process proceeds to step S7, where it is determined whether or not the drive wheel 13 is rotating in the direction opposite to the traveling direction. That is, when the forward drive range (D range) is selected by the select lever, when the drive wheel 13 rotates in the backward direction, the drive wheel 13 rotates in the direction opposite to the advance direction. It will be determined. On the other hand, when the reverse traveling range (R range) is selected by the select lever, when the driving wheel 13 rotates in the forward direction, the driving wheel 13 rotates in the direction opposite to the traveling direction. It will be determined. Note that whether or not the drive wheel 13 has rotated is determined based on an output signal from the rotation angle sensor 46. That is, based on the rotation angle of the rotor 30 interlocked with the drive wheel 13, it is determined whether or not the drive wheel 13 has rotated in the direction opposite to the traveling direction.

  If it is determined in step S7 that the drive wheel 13 is not rotating in the reverse direction, the process proceeds to step S4, and the output suppression mode of the electric oil pump 40 is continued. On the other hand, if it is determined in step S7 that the drive wheel 13 is rotating in the reverse direction, the process proceeds to step S6, and the output suppression mode of the electric oil pump 40 is released. As described above, even when the brake operation is continued, when the reverse rotation of the drive wheel 13 is detected, the output suppression mode of the electric oil pump 40 is canceled and the electric oil pump 40 is discharged. Pressure is raised. Thus, when reverse rotation of the drive wheel 13 is detected during the execution of the output suppression mode, the discharge pressure of the electric oil pump 40 is quickly raised to suppress unnecessary backward movement of the vehicle. In addition, the continuously variable transmission 15 can be protected by suppressing the sliding of the drive chain 26.

  For example, if the occupant loosens the depression of the brake pedal 54 in preparation for a restart, the vehicle may move backward due to gravity before the brake operation is completely released depending on the magnitude of the road surface gradient. That is, when the output suppression mode of the electric oil pump 40 is executed on a steep uphill, if the output suppression mode is canceled after the brake operation is released, the discharge pressure of the electric oil pump 40 is sufficiently increased. There is a risk that the vehicle will move backwards before doing. As shown in FIG. 1, since the drive wheels 13 and the continuously variable transmission 15 are connected, if the vehicle moves backward before the control hydraulic pressure for the continuously variable transmission 15 is ensured, the secondary pulley 24. May cause the drive chain 26 to slip and impair the durability of the continuously variable transmission 15. On the other hand, even when the brake operation is continued, when the reverse rotation of the drive wheel 13 is detected, the output suppression mode is canceled and the discharge pressure of the electric oil pump 40 is increased. Thus, it is possible to protect the continuously variable transmission 15 by suppressing the slippage of the drive chain 26. Further, by quickly canceling the output suppression mode based on the reverse rotation of the drive wheels 13, it is possible to sufficiently secure the torque capacity of the continuously variable transmission 15 before restarting. Torque can be transmitted smoothly to the drive wheels 13. Since the rotation angle sensor 46 of the motor generator 12 is used when detecting the reverse rotation of the drive wheel 13, it is possible to detect a small reverse rotation of the drive wheel 13 while suppressing costs. .

  Next, the execution status of the output suppression mode will be described using a timing chart. FIGS. 4A to 6A are explanatory diagrams showing the traveling state of the vehicle, and FIGS. 4A to 6B are timing charts showing an example of the execution state of the output suppression mode. FIG. 4 shows the execution status of the output suppression mode on a flat road, and FIGS. 5 and 6 show the execution status of the output suppression mode on an uphill road. The road slope of the uphill road shown in FIG. 6 is larger than the road slope of the uphill road shown in FIG. That is, the uphill road of FIG. 6 is steeper than the uphill road of FIG. In addition, in the rotor rotation angle shown in FIGS. 4 to 6, the rotation angle of the rotor 30 when the vehicle is stopped is displayed as “0”. The forward direction of the rotor rotation angle means the rotation direction of the rotor 30 corresponding to the traveling direction of the drive wheel 13, and the reverse direction of the rotor rotation angle corresponds to the reverse direction of the traveling direction of the drive wheel 13. This means the direction of rotation of the rotor 30.

  As shown in FIGS. 4 and 5, when the depression amount of the brake pedal 54 reaches a predetermined value Ba (reference X1) and the vehicle speed decreases to a predetermined value (reference value) Va (reference X2), the output suppression mode is set. This is executed to lower the discharge pressure of the electric oil pump 40. As described above, in the output suppression mode, the required discharge pressure, that is, the target value of the discharge pressure is set based on the road surface gradient. As shown in FIG. 4, the required discharge pressure is set to Pa when the road surface gradient is small, while the required discharge pressure is set to Pb higher than Pa when the road surface gradient is large as shown in FIG. Is done. That is, as shown in FIG. 4, when the road surface gradient is small, the discharge pressure of the electric oil pump 40 is greatly reduced. On the other hand, as shown in FIG. 5, when the road surface gradient is large, the discharge pressure of the electric oil pump 40 is reduced. Is reduced slightly. In the uphill road shown in FIG. 6 to be described later, since the road surface gradient is larger than that of the uphill road in FIG. 5, the required discharge pressure in the output suppression mode is set to Pc higher than Pb. Subsequently, as shown in FIGS. 4 and 5, when the depression amount of the brake pedal 54 becomes equal to or less than a predetermined value Ba (reference numeral X3), that is, when the release of the brake operation by the occupant is detected, the output suppression mode is released. Thus, the discharge pressure of the electric oil pump 40 is increased.

  Thus, at the time of a stop where the torque capacity of the continuously variable transmission 15 can be reduced, the power suppression of the electric oil pump 40 can be suppressed by executing the output suppression mode to reduce the discharge pressure, and the hybrid It becomes possible to improve the fuel consumption of the vehicle. The required discharge pressure is set low when the road surface gradient is small, while the required discharge pressure is set high when the road surface gradient is large. This makes it possible to quickly raise the discharge pressure of the electric oil pump 40 on an uphill road where a quick return of the discharge pressure is desired. When the occupant's brake operation is released, the output suppression mode is released and the discharge pressure is increased, so that the torque capacity of the continuously variable transmission 15 is sufficiently ensured in preparation for the vehicle to restart. Is possible.

  Further, in the case shown in FIG. 5, the output suppression mode is released along with the release of the brake operation, but as described above, the output is based on the reverse rotation of the drive wheels 13 depending on the magnitude of the road surface gradient. The suppression mode is released. As indicated by reference numeral Y1 in FIG. 6, when the release operation of the depression of the brake pedal is started, the braking force of the drive wheels 13 gradually decreases. Then, as indicated by reference numeral Y2, when the rotation of the rotor 30 in the reverse direction is detected based on the detection signal from the rotation angle sensor 46, it is before the brake operation release determination is made. However, the output suppression mode is canceled and the discharge pressure of the electric oil pump 40 is increased. Thereby, it is possible to suppress the unnecessary rotation of the rotor 30 as indicated by the symbol Z in FIG. 6, that is, the unnecessary backward movement of the vehicle. Further, as described above, since the output suppression mode is quickly released without waiting for the brake operation release determination, it is possible to suppress the slip of the drive chain 26 and protect the continuously variable transmission 15.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. In the above description, the output suppression mode is executed when the vehicle is stopped regardless of the magnitude of the road surface gradient. However, the present invention is not limited to this. For example, when the road surface gradient exceeds a predetermined reference gradient, that is, when the road surface is a steep uphill road, the output suppression mode may be stopped without reducing the discharge pressure of the electric oil pump 40. In the above description, the output suppression mode is executed before the vehicle is completely stopped. However, the present invention is not limited to this, and the output suppression mode may be executed after the vehicle is completely stopped. In the above description, the release of the brake operation is cited as one of the conditions for canceling the output suppression mode, but the present invention is not limited to this. For example, the output suppression mode may be canceled when the accelerator pedal 52 is depressed, and the output suppression mode may be canceled when the select lever is operated.

  The illustrated vehicle is a hybrid vehicle including the engine 11 and the motor generator 12, but the vehicle to which the present invention can be applied is not limited to the hybrid vehicle. For example, the present invention is applied to any vehicle provided with only the engine 11 as a drive source or an electric vehicle provided with only the motor generator 12 as a drive source as long as the vehicle is provided with the electric oil pump 40. Is possible. It should be noted that the present invention can be applied to a vehicle including an oil pump driven by an engine in addition to the electric oil pump 40, for example.

  In the above description, it is determined based on the detection signal of the rotation angle sensor 46 provided in the motor generator 12 whether or not the drive wheel 13 has rotated in the direction opposite to the traveling direction. There is nothing. For example, reverse rotation of the drive wheel 13 may be detected by providing a rotation angle sensor for the drive wheel 13. Further, by providing a rotation angle sensor for wheels other than the drive wheels 13, the reverse rotation of the drive wheels 13 may be estimated from the reverse rotation of the wheels. Further, the rotation angle sensor 46 is not limited to the resolver described above, and a rotary encoder, for example, may be employed. In the above description, the continuously variable transmission 15 is provided as the hydraulic operation mechanism, but the present invention is not limited to this. For example, a planetary gear type or parallel shaft type automatic transmission may be employed as the hydraulic operation mechanism. Further, as a hydraulic operation mechanism, a hydraulic clutch or a hydraulic brake may be employed without using a speed change mechanism.

10 vehicle control device 12 motor generator (drive source, electric motor)
13 Drive wheel 15 continuously variable transmission (hydraulic operating mechanism)
16 Power transmission path 40 Electric oil pump 50 Control unit (pump control unit)

Claims (5)

A vehicle control device comprising a drive source and drive wheels driven by the drive source,
A hydraulic operation mechanism provided in a power transmission path between the drive source and the drive wheel;
An electric oil pump for supplying hydraulic oil to the hydraulic operating mechanism;
A pump control unit for controlling the discharge pressure of the electric oil pump,
The pump controller
When the vehicle speed is reduced to a reference value by the occupant's brake operation, an output suppression mode for reducing the discharge pressure of the electric oil pump is executed,
A vehicle control device that releases the output suppression mode and raises the discharge pressure of the electric oil pump when the drive wheel rotates in the direction opposite to the traveling direction during execution of the output suppression mode. The vehicle control device according to claim 1,
The vehicle control device, wherein the target value of the discharge pressure in the output suppression mode is set low when the road gradient is small, and is set high when the road gradient is large. The vehicle control device according to claim 1 or 2,
The said pump control part cancels | releases the said output suppression mode and raises the discharge pressure of the said electric oil pump, when a passenger | crew's brake operation is cancelled | released during execution of the said output suppression mode. The vehicle control device according to any one of claims 1 to 3,
The vehicle control device, wherein the hydraulic operation mechanism is a continuously variable transmission. In the vehicle control device according to any one of claims 1 to 4,
The drive source is an electric motor including a rotor,
The pump control unit determines whether or not the drive wheel has rotated in a direction opposite to a traveling direction based on a rotation angle of the rotor.

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