JP5282752B2 - Oil pump control device for automatic transmission in hybrid vehicle - Google Patents

Description

  The present invention relates to an oil pump control device for an automatic transmission in a hybrid vehicle having a motor and an engine, and more particularly, to control an electric oil pump that generates hydraulic pressure for a CVT (continuously variable transmission) regardless of whether the engine is started or stopped. Relates to the device.

Conventionally, the CVT hydraulic pump of an engine vehicle has been mainly used as a mechanically driven hydraulic pump by engine rotation. However, in a hybrid vehicle that can run independently by an engine and a motor, the engine is stopped. Since it is necessary to operate the CVT even when the motor travels, an electric oil pump is employed.
However, when the electric oil pump of this hybrid vehicle is operated when the road noise is low, such as when the vehicle is stopped or when the motor is running at a low speed, the operation sound of the electric oil pump may be heard and may be heard.

Patent Document 1 (Japanese Patent Laid-Open No. 2000-18377) is known as a technique relating to such an operation noise reduction of an oil pump.
As shown in FIG. 5, this patent document 1 discloses an automatic transmission for a vehicle in which a transmission ratio of a transmission 02 is controlled by a transmission control device 03 using a hydraulic pressure supplied from an oil pump 01. Yes.
The supply pressure (line pressure) from the oil pump 01 to the hydraulic drive mechanism of the transmission (continuously variable transmission) 02 is controlled by the control device 04, and in particular, when the brake is depressed, the line is operated under a stopping condition below a predetermined low vehicle speed. A technique is disclosed in which the drive energy and pump noise of the electric motor 05 that drives the oil pump 01 are reduced by lowering the pressure below the minimum line pressure.

JP 2000-18377 A

However, Patent Document 1 is for reducing the rotational speed of the oil pump 01 at the time of braking and at a predetermined low vehicle speed or less, and is only a region where operating conditions for reducing the rotational speed of the oil pump are limited. The noise reduction effect of the oil pump 01 is limited.
Further, since Patent Document 1 is a power transmission mechanism for transmitting the output of the motor 06 and further the output of the engine 010 to the wheels 08 via the transmission 02 as shown in FIG. 5, the oil pump 01 is operated. Therefore, it is difficult to reduce the noise by stopping the oil pump 01.

  Therefore, the present invention has been made in view of these problems. In a hybrid vehicle having an engine and a motor and capable of running on each of them, the operation frequency of the electric oil pump that operates the CVT is reduced, or the oil pump output It is an object to reduce pump operating noise by reducing the noise.

  In order to solve the above-described problems, the present invention provides an engine, an automatic transmission that changes the rotation input from the engine side according to the vehicle speed and the accelerator opening, and outputs the driving force of the vehicle, and the engine. A driving motor that outputs the driving force of the vehicle in a separate system from the output from the automatic transmission so that the vehicle can run even when stopped, and an electric motor that supplies hydraulic pressure for shift control to the automatic transmission An oil pump, a gear ratio detecting means for detecting the gear ratio of the automatic transmission, and the gear ratio becomes a predetermined overdrive value when the engine is stopped and the traveling motor travels at a speed equal to or lower than the first vehicle speed. And a control means for operating the electric oil pump and stopping the electric oil pump when the gear ratio reaches a predetermined overdrive value.

  According to this invention, while the motor is running with the engine below the first vehicle speed stopped, the transmission oil pressure is supplied from the electric oil pump until the transmission ratio reaches a predetermined overdrive value, and the transmission control is performed. When the predetermined overdrive speed ratio is reached, the electric oil pump is stopped and the overdrive speed ratio is maintained. Therefore, the operation of the electric oil pump is stopped when the predetermined overdrive speed ratio is reached until the vehicle speed is increased to a predetermined vehicle speed, so that the pump operation frequency is reduced and a noise reduction effect is obtained. Furthermore, power consumption by a useless electric oil pump is suppressed.

  Further, since the predetermined overdrive speed ratio is maintained, the engine speed and the automatic speed change are increased when the vehicle speed increases to exceed the first vehicle speed and reaches the region where engine travel is added to restart the engine. The input speed difference of the machine can be reduced, and the shock at engine restart can be reduced.

In the present invention, it is preferable that the output of the electric oil pump is reduced to a second vehicle speed lower than the first vehicle speed as compared with the case of driving exceeding the second vehicle speed.
That is, at a second vehicle speed lower than the first vehicle speed, the output of the electric oil pump while the motor is running with the engine stopped is reduced as compared with the case of driving exceeding the second vehicle speed. The noise of the electric oil pump can be reduced.

In the present invention, it is preferable that the vehicle further includes stop detection means for detecting when the vehicle is stopped, and the control means stops the engine and the electric oil pump while the vehicle is stopped.
Thus, since the engine and the electric oil pump are stopped while the vehicle is stopped, it is possible to effectively reduce the noise of the engine and the electric oil pump when the vehicle is stopped.

In the present invention, it is preferable that the control means operates the electric oil pump to set the low gear ratio before stopping when the motor travels with the engine stopped at the first vehicle speed or lower.
In this way, when the motor is running, the electric oil pump is operated before the vehicle is stopped to obtain a low gear ratio. Therefore, before starting the vehicle, the low gear ratio is reliably controlled in preparation for the start from the stop. In this case, startability can be secured.

  According to the present invention, in a hybrid vehicle having an engine and a motor that can run independently, the operating frequency of the electric oil pump that operates the CVT is reduced, or the oil pump output is reduced to reduce pump operating noise. be able to. Furthermore, power consumption of the electric oil pump can be suppressed.

It is explanatory drawing which shows the whole structure of a hybrid vehicle. It is a flowchart which shows the control flow in an oil pump control apparatus. It is explanatory drawing which shows the relationship between the gear ratio at the time of an electric pump drive, an engine speed, and a vehicle speed. FIG. 4 is a comparative explanatory view corresponding to FIG. 3 showing a relationship among a gear ratio, an engine speed, and a vehicle speed when the electric pump is stopped. It is explanatory drawing of a prior art.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

The overall configuration of the hybrid vehicle 1 will be described with reference to FIG.
This hybrid vehicle is capable of traveling independently of the motor by the first motor generator 2, the engine alone by the engine 4, and the motor engine traveling by both the first motor generator 2 and the engine 4. .

In the first motor generator 2, the output shaft of the first motor generator 2 is directly connected to a rear shaft differential 8 provided on the rear axle 6 to drive the left and right rear wheels 10, 10.
The engine 4 is disposed in front of the vehicle, and a belt-type CVT (continuously variable transmission) 12 is connected to the engine output. That is, the crankshaft of the engine 4 is connected to a primary pulley (not shown) via a torque converter (fluid coupling) 14 and a clutch 16 for forward / reverse switching, and the primary pulley is a secondary pulley (not shown) by an endless belt. The secondary pulley is connected to a front differential gear 20 provided on the front axle 18 via a speed reduction mechanism to drive the left and right front wheels 22,22.

Thus, the CVT 12 is configured by unitizing the torque converter (fluid coupling) 14, the forward / reverse switching clutch 16, the primary pulley, and the secondary pulley. The CVT 12 is not limited to the belt type, and may be other types such as a toroidal type CVT.
Further, the first motor generator 2 and the engine 4 are reversed in the front-rear arrangement relationship, and the first motor generator 2 is provided on the front axle 18, and the engine 4 and the CVT 12 are arranged on the rear axle 6. May be.

  In addition, an electric pump (electric oil pump) 24 is provided to control the transmission ratio of the CVT 12, and the operation of the electric pump 24 is performed by an oil pump control device (control means) 28 in the ECU (electronic control unit) 26. Be controlled. By controlling the electric pump 24, the supply of hydraulic oil to the hydraulic actuator for operating the primary pulley and the secondary pulley of the CVT 12 is controlled, and the effective diameter of both pulleys is changed to change the gear ratio. The driving force of the engine is decelerated according to the gear ratio and transmitted to the front wheels 22 and 22. The speed ratio control is changed according to the vehicle speed and the accelerator opening so as to output the driving force of the vehicle.

  As described above, the ECU 26 is provided with the oil pump control device 28 that controls the electric pump 24, an engine control device (not shown) that controls the start, stop, and rotation speed of the engine 4, and a battery. A battery control device (not shown) for monitoring the charging state of the battery 30 and issuing a power generation command to the first motor generator 2 and the second motor generator 32 to control charging of the battery 30 is provided.

  A second motor generator 32 that is linked to the crankshaft is attached to the front end of the engine 4. The second motor generator 32 receives a control command from the ECU 26, converts the DC power output from the battery 30 into three-phase AC power by the inverter 34 when the motor is driven, and supplies it to the second motor generator 32. During the regenerative operation of the second motor generator 32, the three-phase AC power output from the second motor generator 32 is converted to DC power and the battery 30 is charged.

  Similarly to the second motor generator 32, the first motor generator 2 connected to the rear shaft differential device 8 receives a control command from the ECU 26 and converts the DC power output from the battery 30 when the motor is driven into an inverter. 34, the three-phase AC power is converted into three-phase AC power and supplied to the first motor generator 2. On the other hand, during the regenerative operation of the first motor generator 2, the three-phase AC power output from the first motor generator 2 is converted into DC power. The battery 30 is charged.

  The ECU 26 also receives a signal from a speed ratio sensor 36 that detects the speed ratio from the rotational speeds of the primary pulley and the secondary pulley of the CVT 12 and a signal from a vehicle speed sensor 38 that detects the vehicle speed from the rotational speed of the secondary pulley. And used for control of the oil pump control device 28. Further, since the vehicle speed sensor 38 detects that the vehicle is stopped when the vehicle speed is zero, it also functions as a stop detection means.

In the hybrid vehicle configured as described above, in the case of a low speed range (for example, 30 km / h or less), the motor alone travels only by driving the motor by the first motor generator 2, and the middle and high speed range (for example, 30 km / h) or when the load such as climbing is large, engine running by the engine 4 is added, and motor running by the first motor generator 2 and engine running by the engine 4 are used in combination.
When the vehicle speed of 30 km / h exceeds the threshold value of the first vehicle speed, the engine 4 is activated and a driving force from the engine 4 is applied to generate a torque shock in the vehicle body. In order to suppress the occurrence of this torque shock as much as possible, the transmission ratio of the CVT 12 and the output of the electric pump 24 are controlled by an oil pump controller 28 described later.

Next, the gear ratio control by the oil pump control device 28 will be described with reference to the control flow of FIG.
First, when starting in step S1, it is determined in step S2 whether or not the vehicle is stopped. In this determination, the stop state is determined by the stop detection means including the vehicle speed sensor 38. If the vehicle speed is zero, it is determined that the vehicle is stopped, and the drive duty ratio of the electric pump 24 is set to zero% in step S8. That is, the output of the electric pump 24 is stopped.
As described above, since the gear ratio of the CVT 12 does not change when the vehicle speed is zero, the electric pump 24 is stopped, so that the noise of the electric pump 24 is eliminated and the noise is reduced. Noise can be effectively reduced. Furthermore, power consumption by a useless electric pump is suppressed.

  When it is determined in step S2 that the vehicle is not stopped, that is, when the vehicle is traveling, the engine 4 is stopped and the motor is traveling by the first motor generator 2. As shown in FIG. 1, when the engine 4 stops running, the CVT 12 speed ratio is changed to the Hi side so as not to become an excessive load during running of the motor, and the torque when the engine 4 is restarted. In order to suppress the occurrence of shock, gear ratio control is performed by the electric pump 24 so as to change the gear ratio toward the overdrive side.

  Further, during the motor running by the first motor generator 2 while the engine 4 is stopped, the forward / reverse switching clutch 16 may be disengaged to be in a substantially neutral state. By disengaging the clutch 16 in this way, an extra traveling load during motor traveling is reduced, and fuel efficiency is improved.

  Next, if the vehicle is not stopped in step S2, the process proceeds to step S3 to determine whether the vehicle speed is lower than the first vehicle speed, for example, less than 10 km / h. When the vehicle speed is less than 10 km / h, the process proceeds to step S7 and the drive duty ratio of the electric pump 24 is reduced. That is, the vehicle speed is set to a value smaller than a normal drive duty ratio of 10 km / h or more. For example, it is set to about 30% of the rated output of the electric pump 24 (a value larger than the lowest duty ratio that can be driven by the pump and smaller than the normal duty ratio).

In this way, at a low vehicle speed such as less than 10 km / h, the drive duty ratio of the electric pump 24 is operated at a small ratio of about 30%, so that the noise of the electric pump 24 in the low vehicle speed region can be reduced. . In addition, since the drive duty ratio is operated at a small ratio of about 30%, it is used in an operation region having a margin with respect to the rated output of the electric pump 24. Noise generation from the pump 24 can be suppressed.
As a result, it is possible to effectively reduce the noise from the electric pump 24 even under a situation where road noise is low in the low-speed driving range and even when the engine is stopped and the operating sound of the electric pump 24 is heard.

Next, when it is determined in step S3 that the vehicle speed is 10 km / h or more, the process proceeds to step S4, and it is determined whether the speed ratio is 0.5 or less. The speed ratio is determined based on the detection signal from the speed ratio sensor 36. If the speed ratio is on the overdrive side of 0.5 or less, the drive duty ratio of the electric pump 24 is set to zero% in step S5. That is, the output of the electric pump 24 is stopped. When the operation of the electric pump 24 is stopped, the gear ratio at that time is maintained, so that the overdrive state of 0.5 or less is maintained.
As a result, the frequency of operation of the electric pump 24 is reduced, an effect of reducing noise is obtained, and power consumption by the useless electric pump 24 is further suppressed.

  Furthermore, since the overdrive speed ratio is maintained at 0.5 or less, the vehicle speed increases to exceed the first vehicle speed (30 km / h), and the drive torque from the engine 4 is added to the motor travel by the first motor generator 2. When the engine 4 is started after reaching the above-mentioned range, the difference between the engine speed and the CVT 12 can be reduced, and the shock generated when the engine is started at the first vehicle speed or higher can be reduced.

  Note that when the engine 4 is stopped and the clutch 16 for forward / reverse switching is disengaged to achieve a substantially neutral state, the clutch 16 is connected after starting the engine exceeding the first vehicle speed. Shock can be reduced.

When the gear ratio exceeds 0.5 in step S4, that is, when the overdrive is not established, the process proceeds to step S6 to increase the drive duty ratio of the electric pump 24. That is, driving is performed at a driving duty ratio of about 40%, and the speed ratio is shifted to the overdrive side. In step S9, the process returns and ends.
Note that the overdrive side gear ratio of 0.5, the first vehicle speed of 30 km / h, and the second vehicle speed of 10 km / h are examples, respectively, depending on the timing of starting the engine 4, the rated output of the electric pump 24, and the like. An optimal threshold is set.

  Further, although not shown in the flowchart of FIG. 2, the oil pump control device 28 operates the electric pump 24 when the motor is running with the engine 4 stopped at the first vehicle speed (30 km / h) or less. The low gear ratio may be set before stopping. In other words, the electric pump 24 is operated immediately before the vehicle speed becomes almost zero to obtain a low gear ratio. For this reason, since the low gear ratio can be reliably controlled in preparation for the start from the stop before the stop, startability can be ensured at the start by the motor running.

Next, the result of confirming the change state of the transmission gear ratio according to whether the electric pump 24 is driven or not will be described with reference to FIGS.
FIG. 3 shows a change state of the gear ratio when the electric pump 24 is driven. While the engine 4 is stopped while the motor is being driven by the first motor generator 2, for example, between t _{0 and} t ₁ , the gear ratio is gradually decreased from the Lo side to the Hi side by the electric pump 24, to the overdrive side. It is shown to change.

On the other hand, FIG. 4 shows a case where the electric pump 24 is not driven. During the stop of the engine 4, for example, between t _{2 and} t ₃ , the speed ratio change state when the engine is stopped is maintained and becomes constant. It is shown that.

3 and 4, V ₀ indicates the first vehicle speed at which the engine 4 starts, and is set to, for example, 30 km / h in the present embodiment as described above.
As shown in FIGS. 3 and 4, the operation of the electric pump 24 causes the gear ratio to gradually decrease from the Lo side to the Hi side and change to the overdrive side, thereby reducing the shock at the time of starting the engine at the first vehicle speed or higher. Is done.

  According to the present invention, in a hybrid vehicle having an engine and a motor that can run independently, the operating frequency of the electric oil pump that operates the CVT is reduced, or the oil pump output is reduced to reduce pump operating noise. be able to. Furthermore, since the electric power consumption of the electric oil pump can be suppressed, it is suitable for use in an oil pump control device of an automatic transmission in a hybrid vehicle.

DESCRIPTION OF SYMBOLS 1 Hybrid vehicle 2 1st motor generator (traveling motor)
4 Engine 8 Rear axle differential 12 CVT (automatic transmission)
14 Torque converter (fluid coupling)
16 Clutch 20 Front shaft differential 24 Electric pump (electric oil pump)
26 ECU
28 Oil pump control device (control means)
30 Battery 32 Second motor generator 34 Inverter 36 Gear ratio sensor (speed ratio detection means)
38 Vehicle speed sensor (stop detection means)

Claims (4)

An engine, and an automatic transmission that outputs the driving force of the vehicle by shifting the rotation input from the engine side according to the vehicle speed and the accelerator opening;
A traveling motor that outputs the driving force of the vehicle in a separate system from the output from the automatic transmission to enable the vehicle to travel even when the engine is stopped;
An electric oil pump for supplying hydraulic pressure for shift control to the automatic transmission;
Gear ratio detecting means for detecting a gear ratio of the automatic transmission;
When the engine is stopped and the vehicle is driven by the traveling motor at a speed equal to or lower than the first vehicle speed, the electric oil pump is operated until the gear ratio reaches a predetermined overdrive value, and the gear ratio is set to a predetermined overdrive value. Control means for stopping the electric oil pump,
An oil pump control device for an automatic transmission in a hybrid vehicle.   3. The automatic in a hybrid vehicle according to claim 1 or 2, wherein the electric oil pump output is reduced to a second vehicle speed lower than the first vehicle speed as compared with a case of driving exceeding the second vehicle speed. Transmission oil pump control device.   2. The oil for an automatic transmission in a hybrid vehicle according to claim 1, further comprising stop detection means for detecting when the vehicle is stopped, wherein the control means stops the engine and the electric oil pump while the vehicle is stopped. Pump control device.   2. The hybrid vehicle according to claim 1, wherein the control means operates the electric oil pump to set a low gear ratio before stopping when the motor travels with the engine stopped at the first vehicle speed or less. 3. Oil pump control device for automatic transmission in Japan.

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