KR20150008328A - Oil pump system of hybrid vehicle and method for controlling the same - Google Patents

Abstract

The present invention relates to an oil pump system of a hybrid vehicle and a method to control the same. According to an embodiment of the present invention, the oil pump system used to supply hydraulic operation power to a transmission of a hybrid vehicle comprises: an electric power oil pump to supply hydraulic operation power to a transmission in accordance to a speed instruction; a data detection unit to detect data to control the electric power oil pump; and a controller to set a driving mode of the electric power oil pump based on the data detected by the data detection unit, to calculate a basic flow rate of the set driving mode, to calculate a final flow rate by compensating for the basic flow rate, and to transmit the speed instruction to the electric power oil pump wherein the hydraulic operation power is supplied to the transmission by only the electric power oil pump, and the speed instruction calculated based on a target hydraulic power, an oil temperature, and the final flow rate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an oil pump system for a hybrid vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an oil pump system for a hybrid vehicle and a control method thereof, and more particularly, to an oil pump system and a control method thereof for supplying a hydraulic pressure to a transmission using only an electric oil pump.

As is known, a hybrid vehicle uses an engine and battery power together. That is, the hybrid vehicle efficiently combines the power of the engine and the power of the motor.

The hybrid vehicle is usually equipped with an automatic transmission and an oil pump system that uses a mechanical oil pump (MOP) and an electric oil pump (EOP) together to supply the operating hydraulic pressure to the automatic transmission Is used.

The mechanical oil pump is driven by the power of the engine to supply oil to the automatic transmission. Therefore, when the operation of the engine is stopped, the mechanical oil pump is also stopped and the oil can not be supplied, so that the electric oil pump driven separately from the engine is mounted. For example, the oil pump system of a conventional hybrid vehicle is divided into a stop, a low speed and a high speed section in accordance with a running state (speed), only an electric oil pump is operated in a stop section, a mechanical oil pump and an electric oil pump And the oil pump control method in which only the mechanical oil pump is operated in the high speed section can be applied. That is, in the conventional oil pump system, the electric oil pump is used to assist the deficient operating oil pressure of the mechanical oil pump.

Since the mechanical oil pump is always operated in accordance with the engine start, unnecessary power loss may be caused and the fuel efficiency may be lowered. In addition, the use of mechanical oil pumps and electric oil pumps at the same time can increase production costs.

Therefore, there is a need for a method of eliminating the mechanical oil pump and supplying the oil to the automatic transmission in a single operation of the electric oil pump.

The matters described in the background section are intended to enhance the understanding of the background of the invention and may include matters not previously known to those skilled in the art.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an oil pump system and a control method thereof for reliably supplying operating oil pressure to a transmission by a single drive of an electric oil pump, And a method thereof.

An oil pump system for supplying operating oil pressure to a transmission of a hybrid vehicle according to an embodiment of the present invention includes an electric oil pump for supplying operating oil pressure to the transmission in accordance with a speed command; A data detector for detecting data for controlling the electric oil pump; And a control unit for setting the drive mode of the electric oil pump based on the data detected by the data detection unit, calculating the basic flow rate of the set drive mode, calculating the final flow rate by compensating the basic flow rate, Wherein the operating oil pressure is supplied to the transmission only by the electric oil pump, and the speed command is calculated based on the target oil pressure, the oil temperature, and the final flow rate.

The driving mode may include a first control mode set at a stop condition and a second control mode set at a driving condition.

The driving mode may further include a third control mode set in a departure condition, and the third control mode may be maintained for a set time.

The controller can calculate the basic flow rate of the set drive mode from the basic flow map for the relationship between the oil temperature, the target oil pressure, and the basic flow rate for each drive mode.

The controller may calculate a compensated flow rate required for cooling, lubricating, slipping, and leaking of the transmission, and adding the compensated flow rate to the basic flow rate to calculate the final flow rate.

The controller calculates the speed command from the speed command map, and the speed command map may be a three-dimensional map of the relationship between the target hydraulic pressure, the oil temperature, the final flow rate, and the speed command.

The electric oil pump can be continuously operated from the start of the hybrid vehicle until the start of the hybrid vehicle.

A method of controlling an oil pump system for supplying an operating oil pressure to a transmission of a hybrid vehicle according to an embodiment of the present invention includes: setting a drive mode of the electric oil pump based on data detected from a data detector; Calculating a basic flow rate of the set drive mode; Calculating a final flow rate based on the basic flow rate; Calculating a speed command of the electric oil pump based on the target oil pressure, the oil temperature, and the final flow rate; And controlling driving of the electric oil pump according to the calculated speed command.

The driving mode may include a first control mode set at a stop condition and a second control mode set at a driving condition.

The driving mode may further include a third control mode set in a departure condition, and the third control mode may be maintained for a set time.

The basic flow rate can be calculated from the basic flow map for the relationship between the oil temperature, the target hydraulic pressure, and the basic flow rate for each drive mode.

The method for controlling the oil pump system further includes the step of calculating a compensated flow rate required for cooling, lubricating, slipping, and leaking of the transmission, wherein the final flow rate is the sum of the compensated flow rate Can be calculated.

The speed command can be calculated from a three-dimensional map of the relationship between the target hydraulic pressure, the oil temperature, the final flow rate, and the speed command.

As described above, according to the embodiment of the present invention, the fuel efficiency can be improved and the production cost can be reduced by driving the electric oil pump alone.

Further, by using the three-dimensional map of the target oil pressure, the oil temperature, the final flow rate, and the speed command of the electric oil pump, the operating oil pressure can be supplied to the transmission as accurately and stably as required.

1 is a configuration diagram of an oil pump system of a hybrid vehicle according to an embodiment of the present invention.
2 is a flowchart of a method of controlling an oil pump system of a hybrid vehicle according to an embodiment of the present invention.
3 and 4 are views showing driving modes of the electric oil pump according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are given the same reference numerals throughout the specification.

In addition, since the components shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to those shown in the drawings.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

1 is a configuration diagram of an oil pump system of a hybrid vehicle according to an embodiment of the present invention.

Referring to FIG. 1, an oil pump system of a hybrid vehicle according to an embodiment of the present invention includes a transmission 50, an electric oil pump (EOP) 60, a controller 70, and a data detector 90 do. The power train system of the hybrid vehicle includes an engine 10, a hybrid starter and generator 12, an engine clutch 20, a drive motor 30, a battery 40, a transmission 50, And an axle 80.

Power transmission of the hybrid vehicle is performed by selectively transmitting the power generated by the engine 10 or the drive motor 30 to the input shaft 52 of the transmission 50 and from the output stage 54 of the transmission 50 And the output power is transmitted to the axle 80 via the longitudinal deceleration device 84 and the differential gear device 86. The hybrid vehicle travels by the power generated by the engine 10 or the drive motor 30 by rotating the wheel 82 with the axle 80. [

The HSG 12 is operated as a motor to start the engine 10 or to operate as a generator when surplus output is generated in a state where the engine 10 maintains the startup state to charge the battery 40 do.

The engine clutch 20 is mounted between the engine 10 and the drive motor 30 to connect or disconnect power.

The battery 40 stores a high voltage and supplies the driving voltage to the driving motor 30 and is charged by the regenerative energy generated by the driving motor 30 during driving of the hybrid vehicle.

The power transmission and regenerative braking of such a hybrid vehicle are obvious to those skilled in the art (hereinafter, those skilled in the art will be apparent to those skilled in the art).

The transmission 50 is a device for performing gear shifting by changing a gear ratio connected from the input shaft 52 to the output stage 54. In addition, the transmission 50 performs the shifting in accordance with the operation of the plurality of friction elements including at least one brake and at least one clutch. The plurality of friction elements are operated to be engaged or disengaged by an operating hydraulic pressure supplied to the transmission (50).

The electric oil pump 60 pumps the oil to supply operating hydraulic pressure to the engine clutch 20 and the transmission 50. [ The electric oil pump 60 is continuously operated from the start of the hybrid vehicle until the start of the hybrid vehicle. That is, the electric oil pump 60 always operates according to the elimination of the mechanical oil pump.

The data detecting unit 90 detects data for controlling the electric oil pump 60 and the data detected by the data detecting unit 90 is transmitted to the controller 70.

The data detecting section 90 may include an accelerator pedal position sensor 91, a brake pedal position sensor 92, a vehicle speed sensor 93, a speed change stage sensor 94 and an oil temperature sensor 95.

The accelerator pedal position sensor 91 measures information on which the driver depresses the accelerator pedal. That is, the accelerator pedal position sensor 91 measures data related to the driver's acceleration intention.

The brake pedal position sensor 92 detects whether or not the brake pedal is depressed. That is, the brake pedal position sensor 92 detects the driver's acceleration intention together with the accelerator pedal position sensor 91.

The vehicle speed sensor 93 measures the speed of the vehicle and is mounted on a wheel of the vehicle. Alternatively, the vehicle speed may be calculated based on the GPS signal received by a global positioning system (GPS).

On the other hand, based on the signal of the accelerator pedal position sensor 91 and the signal of the vehicle speed sensor 93, the target speed change stage can be calculated using the speed change pattern, and the shift to the target speed change stage is controlled. That is, in the case of an automatic transmission having a plurality of planetary gear sets and a plurality of friction elements, the hydraulic pressure supplied to or released from the plurality of friction elements is regulated. Further, in the case of the dual clutch transmission, the currents applied to the plurality of synchronizer mechanisms and the actuators are controlled.

The speed change stage sensor 94 detects the currently engaged speed change stage. The oil temperature sensor 95 detects the temperature of the oil in the transmission 50.

The controller 70 may include a transmission control unit (TCU) 72 and an electric oil pump unit (OPU) 74. The method of controlling the oil pump system of the hybrid vehicle according to the embodiment of the present invention can be performed by the transmission controller 72 and the oil pump controller 74. [

The transmission controller 72 is a device for controlling the torque of the transmission 50 and the operation of the plurality of friction elements. The transmission controller 72 sets the drive mode of the electric oil pump 60 based on the data detected by the data detector 90, calculates the speed command according to the set drive mode, Lt; / RTI >

For this purpose, the transmission controller 72 may be implemented as one or more processors operating according to a set program, and the set program may be executed by the respective steps of the oil pump system control method of the hybrid vehicle according to the embodiment of the present invention May be programmed to perform.

The oil pump controller 74 is connected to the electric oil pump 60 and controls driving of the electric oil pump 60 in accordance with the speed command.

A part of the process of the electric oil pump control method of the hybrid vehicle according to the embodiment of the present invention to be described later may be performed by the transmission controller 72 and the other part of the process is performed by the oil pump controller 74. [ Therefore, in the method of controlling the electric oil pump of the hybrid vehicle according to the embodiment of the present invention, the transmission controller 72 and the oil pump controller 74 can be described as one controller 70, The controller 72 and the oil pump controller 74 will be referred to as a controller 70. [

2 is a flowchart of a method of controlling an oil pump system of a hybrid vehicle according to an embodiment of the present invention.

As shown in FIG. 2, the method for controlling an oil pump system of a hybrid vehicle according to the embodiment of the present invention starts by detecting data for controlling the electric oil pump 60 (S100).

The controller 70 sets the driving mode of the electric oil pump 60 based on the data (S110).

3 and 4 are views showing driving modes of the electric oil pump according to the embodiment of the present invention.

As shown in FIG. 3, the driving mode includes a first control mode and a second control mode.

The first control mode is a mode in which the electric oil pump (60) is driven in a state where the hybrid vehicle is stopped. The first control mode is a mode in which only a minimum necessary hydraulic pressure is supplied in order to minimize power consumption. The controller (70) drives the electric oil pump in the first control mode under the stop condition. For example, the stop condition may be satisfied when the brake ON and vehicle speed are zero, or the speed change stage is a parking speed change stage (P stage) or a neutral speed change stage (N stage).

The second control mode is a mode in which the electric oil pump (60) is driven while the hybrid vehicle is running. The controller (70) drives the electric oil pump (60) in the second control mode at the start or at the driving condition. For example, the running condition may be satisfied when the brake-off or vehicle speed is greater than 0 and the speed change stage is a parking speed change stage (D-stage) or a reverse speed change stage (R-stage).

As shown in FIG. 4, the driving mode may further include a third control mode.

The third control mode is a mode in which the electric oil pump (60) is driven at a high speed while the hybrid vehicle is moving. The third control mode is a mode for instantaneously supplying the hydraulic pressure to the transmission 50 for a set time to ensure hydraulic responsiveness.

That is, when the rotational speed of the electric oil pump 60 can not follow the speed command calculated in the second control mode at the time of switching from the first control mode to the second control mode immediately (for example, ), The oil can be instantaneously pumped to a high pressure for a short period of time to promptly reach the specified pressure state.

The controller (70) may drive the electric oil pump (60) in the third control mode at the start or at the departure condition. The departure condition may be satisfied when the brake mode or the vehicle speed is greater than 0 while the first control mode is set, and the speed change stage is the parking speed change stage (D-stage) or the reverse speed change stage (R-stage).

The controller 70 can calculate the set time based on the two-dimensional map of the relationship between the oil temperature, the target oil pressure, and the set time (third control mode hold time). When the set time has elapsed, the controller 70 converts the drive mode from the third control mode to the second control mode.

After setting the drive mode of the electric oil pump 60 in step S110, the controller 70 calculates the basic flow rate Q1 of the set drive mode from the basic flow map Map in step S120. Here, the basic flow map (Map) may be a two-dimensional map in which information on the basic flow rate is stored for each drive mode, using the oil temperature and the target oil pressure as variables. That is, the controller 70 can calculate the basic flow rate Q1 according to the current oil temperature and the target oil pressure using the information of the basic flow map Map.

In the two-dimensional map of the first control mode, the basic flow rate Q1 may be set to a minimum required flow rate while the hybrid vehicle is stopped. In the two-dimensional map of the second control mode, the basic flow rate Q1 may be set to a flow rate capable of torque transmission in a state where the hybrid vehicle is traveling. The basic flow rate Q1 in the two-dimensional map of the third control mode may be set to a flow rate for ensuring hydraulic responsiveness in a state where the hybrid vehicle is running.

The controller 70 may calculate the compensated flow rate Q2 based on cooling, lubrication, slip and leakage of the engine clutch 20, the drive motor 30 and the transmission 50 (S130).

The controller 70 can calculate the compensated flow rate Q2 required for cooling, lubrication, slip, and leakage of the transmission 50 using the compensated flow map Map. The compensated flow map (Map) has a relationship between the oil temperature, the valve control pressure and the compensated flow rate in consideration of the two-dimensional map (Map) storing information on the relationship between the oil temperature, the heat generation and the compensation flow, And a two-dimensional map (Map) in which information about the two-dimensional map is stored. Here, the method of calculating the compensated flow rate using the compensated flow map (Map) of the controller 70 is only one example, but the present invention is not limited thereto.

For example, the controller 70 is the compensation flow rate (Q2) heating (X of the heat generating (X _1), the transmission output system (differential gear or bearing, and so on) of the drive motor system (motor itself or the bearing, and so on) when calculating slippage of the _two), the bush (bush) system (shaft bush, and so on) the heating (X _3), the planetary gear system (planetary gear, fever (X _4), a plurality of friction elements (clutches and brakes) of a needle roller bearing, etc.) (X ₅ ) and the like may be considered.

In addition, the controller 70 may consider the leakage of the transmission 50 due to excessive control during shifting when computing the compensated flow rate Q2. That is, the controller 70 can calculate the compensated flow rate based on the leakage of a plurality of valves provided in the transmission 50. Those skilled in the art will appreciate that the various parameters, symbols, constants, and the like used in the present specification will be omitted from the detailed description for convenience of explanation.

The heat generation (X ₁ ) of the drive motor system can be calculated from the formula of X ₁ = | w ₁ * (| T ₁ | * k ₁₁ + k ₁₂ ) |. Here, | Is the absolute value function, w ₁ is the rotational speed of the drive motor, T ₁ is the torque of the drive motor, k ₁₁ is the drive motor loss rate, and k ₁₂ is the drive motor bearing drag constant. The drive motor loss rate has a value between 0 and 1 and can be calculated from a two-dimensional map of the relationship between the rotational speed of the drive motor, the absolute value of the torque of the drive motor, and the drive motor loss rate.

The heat generation (X ₂ ) of the transmission output system can be calculated from an equation of X ₂ = No * (| T ₂ | * k ₂₁ + k ₂₂ ). Here, No is the transmission output shaft revolution number, T ₂ is the transmission output shaft torque, K ₂₁ is the output shaft loss rate constant, and K ₂₂ is the output shaft bearing drag constant.

The exotherm X ₃ of the bush system can be calculated from the equation of X ₃ = v ₃ * k ₃ . Where v ₃ is the relative speed of the transmission input shaft bush, and k ₃ is the bass drag. The bush drag has a value between 0 and 10 and can be calculated from a two-dimensional map of the relationship between the oil temperature, the relative speed of the bush, and the bush drag.

The heat generation (X ₄ ) of the planetary gear system can be calculated from the following formula: X ₄ = w ₄ * (| T ₄ | * k ₄₁ + k ₄₂ ) | Here, w ₄ is the rotational speed, T ₄ of the pinion gear is transmitted torque, k ₄₁ of the pinion gear is a pinion gear loss rate constants, k ₄₂ is a constant drag bearing of the planetary gear system. The pinion gear loss rate constant k ₄₁ and the bearing drag constant k ₄₂ of the planetary gear system may be defined for each of the plurality of planetary gear sets.

The heat generation (X ₅ ) at the time of slip of one friction element can be calculated from the equation of X ₅ = v ₅ * (P _{5 -} k ₅₁ ) * k ₅₂ . Where v ₅ is the relative velocity of the friction element, P ₅ is the control pressure of the friction element, k ₅₁ is the kiss point pressure constant of the friction element, and k ₅₂ is the area constant of the friction element. The heat generation at the time of slip of each friction element can be calculated in the same manner as the heat generation at the time of slip of the one friction element.

At this time, the controller 70 may determine the maximum value among the compensation flow rates calculated according to the variables as the compensation flow rate Q2.

Thereafter, the controller 70 calculates the final flow rate Q3 by adding the compensated flow rate Q2 to the basic flow rate Q1 (S140).

The controller 70 calculates a speed command of the electric oil pump 60 from the speed command map Map (S150). Here, the speed command map may be a three-dimensional map in which information on the speed command of the electric oil pump is stored using the target oil pressure, the oil temperature, and the final flow rate as variables. That is, the controller 70 can calculate the speed command of the electric oil pump according to the target oil pressure, the oil temperature, and the final flow rate using the information of the speed command map Map.

The controller 70 controls driving of the electric oil pump 60 based on the calculated speed command (S160). The transmission controller 70 calculates the speed command and transmits the calculated speed command to the oil pump controller 74. The controller 70 controls the oil pump controller 74 and the oil pump controller 74, The oil pump controller 74 can drive the electric oil pump 60 according to the speed command.

Thus, according to the embodiment of the present invention, the fuel efficiency is improved and the production cost is reduced by operating the electric oil pump alone.

Further, by using the three-dimensional map of the target oil pressure, the final flow rate, and the speed command of the electric oil pump, the operating oil pressure can be supplied to the transmission as accurately and stably as required.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

10: engine 12: hybrid starter and generator (HSG)
20: engine clutch 30: drive motor
40: Battery 50: Transmission
60: electric oil pump
70: Controller 72: Transmission control unit
74: electric oil pump unit
80: axle 82: wheel
84: longitudinal reduction device 86: differential gear device
90:

Claims (13)

An oil pump system for supplying operating oil pressure to a transmission of a hybrid vehicle,
An electric oil pump for supplying operating oil pressure to the transmission in accordance with a speed command;
A data detector for detecting data for controlling the electric oil pump; And
Wherein the control unit sets the drive mode of the electric oil pump based on the data detected by the data detection unit, calculates the basic flow rate of the set drive mode, calculates the final flow rate by compensating the basic flow rate, To a controller;
, ≪ / RTI &
Wherein the operating oil pressure is supplied to the transmission only by the electric oil pump, and the speed command is calculated on the basis of the target oil pressure, the oil temperature, and the final flow rate. The method according to claim 1,
Wherein the drive mode includes a first control mode set at a stop condition and a second control mode set at a drive condition. 3. The method of claim 2,
Wherein the driving mode further comprises a third control mode set in a departure condition,
And the third control mode is maintained for a predetermined time. The method according to claim 1,
Wherein the controller calculates the basic flow rate of the set drive mode from the basic flow map for the relationship between the stored oil temperature, the target oil pressure, and the basic flow rate for each drive mode. The method according to claim 1,
Wherein the controller calculates a compensated flow rate required for cooling, lubrication, slip, and leakage of the transmission, and calculates the final flow rate by adding the compensated flow rate to the basic flow rate. system. The method according to claim 1,
The controller calculates the speed command from the speed command map,
Wherein the speed command map is a three-dimensional map of a relationship between a target hydraulic pressure, an oil temperature, a final flow rate, and a speed command. The method according to claim 1,
Wherein the electric oil pump is continuously operated from the start of the hybrid vehicle until the start of the hybrid vehicle. A method of controlling an oil pump system for supplying operating oil pressure to a transmission of a hybrid vehicle,
Setting a drive mode of the electric oil pump based on the data detected from the data detection unit;
Calculating a basic flow rate of the set drive mode;
Calculating a final flow rate based on the basic flow rate;
Calculating a speed command of the electric oil pump based on the target oil pressure, the oil temperature, and the final flow rate; And
Controlling driving of the electric oil pump according to the calculated speed command;
Wherein the oil pump system is a hybrid vehicle. 9. The method of claim 8,
Wherein the drive mode includes a first control mode set at a stop condition and a second control mode set at a drive condition. 10. The method of claim 9,
Wherein the driving mode further comprises a third control mode set in a departure condition,
Wherein the third control mode is maintained for a set time period. 9. The method of claim 8,
Wherein the basic flow rate is calculated from a basic flow map for the relationship between the oil temperature, the target oil pressure and the basic flow rate stored for each drive mode. 9. The method of claim 8,
Further comprising the step of calculating a compensated flow rate required for cooling the transmission, lubrication, slip, and leakage,
Wherein the final flow rate is calculated by adding the compensated flow rate to the basic flow rate. 9. The method of claim 8,
Wherein the speed command is calculated from a three-dimensional map of a relationship between a target hydraulic pressure, an oil temperature, a final flow rate, and a speed command.

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