阅读说明：本技术 用于环保车辆的油温升高系统和方法 (Oil temperature raising system and method for environmentally friendly vehicle ) 是由 金镇湖 李载勋 韩大雄 任廷彬 于 2020-10-23 设计创作，主要内容包括：一种用于环保车辆的油温升高系统和方法,所述系统包括油温检测器和控制器,所述油温检测器配置为检测通过电动油泵流向电机和变速器的油的温度,所述控制器配置为接收油温检测器的检测信号,并且当油温小于预定参考温度时向电机施加用于升温的电流。通过施加至电机的电流使电机的温度升高,使得油温通过电机的热量而升高。(An oil temperature increasing system and method for an eco-friendly vehicle, the system including an oil temperature detector configured to detect a temperature of oil flowing to a motor and a transmission through an electric oil pump, and a controller configured to receive a detection signal of the oil temperature detector and apply a current for increasing temperature to the motor when the oil temperature is less than a predetermined reference temperature. The temperature of the motor is increased by the current applied to the motor, so that the oil temperature is increased by the heat of the motor.)

1. An oil temperature raising system for an environmentally friendly vehicle, the system comprising:

an oil temperature detector configured to detect a temperature of oil flowing to the motor and the transmission through the electric oil pump; and

a controller configured to:

receiving a detection signal of an oil temperature detector;

applying a current for warming to the motor when the oil temperature is less than a predetermined reference temperature;

wherein the temperature of the motor is increased by the current applied to the motor such that the oil temperature is increased by heat of the motor.

2. The oil temperature increasing system for an eco-friendly vehicle according to claim 1, wherein the controller is configured to: when the shift position of the vehicle is the parking position, a current for warming up is applied to the motor as a d-axis current.

3. The oil temperature increasing system for an eco-friendly vehicle according to claim 2, wherein the controller applies a d-axis current for warming to the motor at a predetermined gradient for a predetermined period of time to reach a maximum d-axis current value.

4. The oil temperature increasing system for an eco-friendly vehicle according to claim 1, wherein when the shift range of the vehicle is a forward range, the controller is configured to apply a current for warming to the motor and select an operating point at which the current is maximally applied on an iso-torque line of a current map for driving the motor.

5. The oil temperature increasing system for an eco-friendly vehicle according to claim 1, wherein the controller stops applying the current to the motor when it is detected that the oil temperature is equal to or greater than a predetermined reference temperature after applying the current to the motor.

6. A method of increasing an oil temperature for an environmentally friendly vehicle, the method comprising:

detecting a temperature of oil flowing to the motor and the transmission through the electric oil pump by an oil temperature detector;

applying, by a controller, a current for warming to the motor when a detection signal of the oil temperature detector is received and the oil temperature is less than a predetermined reference temperature;

wherein when the temperature of the motor is increased by applying the current to the motor, the temperature of the oil is increased by heat of the motor.

7. The method according to claim 6, wherein the controller applies the current to the motor as the d-axis current if a shift position of the vehicle is a parking position when the current for warming is applied to the motor.

8. The method of claim 7, wherein the d-axis current is applied to the motor at a predetermined gradient over a predetermined period of time to reach a maximum d-axis current value.

9. The method of claim 6, wherein when applying the current for warming to the motor, the controller selects an operating point at which the current is maximally applied on an iso-torque line of a current map for driving the motor if a gear of the vehicle is a forward gear.

10. The method according to claim 6, wherein the controller stops applying the current to the motor when detecting that the oil temperature is equal to or greater than a predetermined reference temperature after applying the current for warming to the motor.

Technical Field

The invention relates to an oil temperature raising system and method for an environmentally friendly vehicle. More particularly, the present invention relates to a cooling oil temperature increasing system and method for an eco-friendly vehicle, which can apply a current for increasing a temperature to a motor in a low temperature environment to increase the temperature of the motor, while increasing the temperature of oil flowing through an oil circulation passage of the motor, thereby maintaining the viscosity of the oil constant.

Background

Hybrid vehicles, electric vehicles, hydrogen fuel cell vehicles, and the like are equipped with a motor as a drive source. These vehicles are referred to as eco-vehicles or electrically driven vehicles.

Generally, an internal combustion engine vehicle equipped with a gasoline engine or a diesel engine is provided with a mechanical oil pump that is operated using the driving force of the engine that is always driven while the vehicle is running. However, an engine included in a power train of a hybrid vehicle is not always driven, and electric vehicles and fuel cell vehicles do not have an engine, and thus environmentally friendly vehicles such as hybrid vehicles, electric vehicles, and fuel cell vehicles are equipped with an electric oil pump.

Referring to fig. 1, a power train of a hybrid vehicle includes an engine 10 and a motor 12, an engine clutch 11, a transmission 13, a Hybrid Starter Generator (HSG)14, an inverter 15 and a high voltage battery 16, the engine 10 and the motor 12 are arranged in series, the engine clutch 11 is provided between the engine 10 and the motor 12 to transmit or interrupt power of the engine, the transmission 13 converts and outputs the power of the motor or both the motor and the engine to the drive wheels, the Hybrid Starter Generator (HSG)14 is a type of electric machine that is connected to the crankshaft pulley of the engine to produce power for starting the engine and charging the battery, the inverter 15 controls the charge/discharge of the motor 12 and the power generation of the HSG 14, the high-voltage battery 16 is connected to the motor 12 and the HSG 14 via an inverter 15 for charging and discharging.

Further, an Electric Oil Pump (EOP)20 is mounted at a predetermined position of a transmission case covering the transmission 13 so as to be driven under the control of an oil pump control unit (OPU) 21. The electric oil pump 20 is applicable not only to electric vehicles and fuel cell vehicles that use a motor as a drive source, but also to hybrid vehicles.

Here, although not shown in the drawings, a cooling oil circulation path is formed in the motor 12 and the transmission 13.

Therefore, when the oil for cooling and lubrication flows along the oil circulation paths of the motor 12 and the transmission 13 by operating the electric oil pump 20, the motor 12 and the transmission 13 are cooled.

For reference, the oil circulated by operating the electric oil pump 20 may be used to cool the motor and the transmission and lubricate the transmission, in addition to applying the control hydraulic pressure for shifting.

The viscosity of the oil circulated by operating the electric oil pump 20 rises in a very low temperature environment (e.g., -40 ℃). In order to circulate the oil having the increased viscosity, the output of the electric oil pump needs to be further increased.

In order to circulate the oil having the increased viscosity in a very low temperature environment (e.g., -40 ℃), it is necessary to additionally increase the output of the electric oil pump. However, since the electric oil pump mounted on the vehicle has a fixed output according to the Liter Per Minute (LPM) standard specification, there is a limitation in increasing the output for circulating the high viscosity oil.

Further, as a method of easily circulating the high viscosity oil, the electric oil pump may be replaced with a specification having an increased output capacity. However, there is a problem in that, due to an increase in the size of the electric oil pump, packageability may be deteriorated, and cost may be greatly increased.

The foregoing is merely intended to aid in understanding the background of the invention and is not intended to represent the scope of the invention as known in the prior art to those skilled in the art.

Disclosure of Invention

The present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide an oil temperature increasing system and method for an eco-friendly vehicle, in which when the oil temperature is less than a predetermined reference temperature, a current for increasing the temperature is applied to a motor, thereby increasing the temperature of the motor, while increasing the temperature of oil flowing through an oil circulation passage of the motor, thereby maintaining the viscosity of the oil, thereby easily circulating the oil by an electric oil pump.

To achieve the object of the present invention, according to an aspect of the present invention, an oil temperature increasing system for an eco-friendly vehicle includes: an oil temperature detector configured to detect a temperature of oil flowing to the motor and the transmission through the electric oil pump, and a controller configured to receive a detection signal of the oil temperature detector and apply a current for warming to the motor when the oil temperature is less than a predetermined reference temperature; wherein the temperature of the motor may be increased by the current applied to the motor, so that the oil temperature may be increased by heat of the motor.

The controller may be configured to apply a d-axis current to the motor as a current for warming when the shift position of the vehicle is the P range.

When the d-axis current for warming is applied to the motor, the controller may apply the current at a predetermined gradient for a predetermined period of time to reach a maximum d-axis current value.

When the shift range of the vehicle is the D range, the controller may be configured to apply a current for warming to the motor and select an operating point at which the current is maximally applied on an iso-torque line of a current map for driving the motor.

The controller may stop applying the current for warming to the motor when it is detected that the oil temperature is equal to or greater than a predetermined reference temperature after applying the current for warming to the motor.

According to another aspect of the present invention, an oil temperature increasing method for an eco-friendly vehicle includes: detecting a temperature of oil flowing to the motor and the transmission through the electric oil pump by an oil temperature detector; applying, by a controller, a current for warming to the motor when a detection signal of the oil temperature detector is received and the oil temperature is less than a predetermined reference temperature; wherein when the temperature of the motor is increased by applying the current to the motor, the temperature of the oil is increased by heat of the motor.

When the shift position of the vehicle is the P range, the controller may apply the d-axis current to the motor as the current for warming up.

When the d-axis current for warming is applied to the motor, the current may be applied at a predetermined gradient for a predetermined period of time to reach a maximum d-axis current value.

When the shift range of the vehicle is the D range, the controller may change the operating point of the motor to an operating point at which the current is maximally applied on the iso-torque line of the current map for driving the motor.

After the oil temperature is increased, the controller may stop applying the current for increasing the temperature to the motor when the oil temperature is detected to be equal to or greater than a predetermined reference temperature.

With the above object, the present invention provides the following effects.

First, when stopping or running under low-temperature environmental conditions, a current for warming is applied to the motor to raise the temperature of the motor, and heat of the motor caused by the temperature rise is transferred to oil flowing through an oil circulation passage of the motor, thereby preventing the viscosity of the oil from rising in the low-temperature environment while maintaining the viscosity of the oil, so that the oil can be easily circulated by the electric oil pump.

Second, the control operation is performed such that only the electric current for warming is applied to the motor without replacing the electric oil pump with a specification having an increased output capacity, thereby achieving cost reduction, and the existing electric oil pump can be used without special modification, thereby optimizing packageability for each vehicle type.

Drawings

The above and other objects, features, and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a power transmission schematic diagram showing one example of a powertrain of a hybrid vehicle;

fig. 2 is a control block diagram showing an oil temperature increasing system for an eco-friendly vehicle according to an exemplary embodiment of the present invention;

fig. 3 is a flowchart illustrating an oil temperature increasing method for an eco-friendly vehicle according to an exemplary embodiment of the present invention;

fig. 4 is a graph showing a method of applying a current for increasing a temperature to a motor to increase an oil temperature when an eco-vehicle according to an exemplary embodiment of the present invention is parked;

fig. 5 is a graph showing a method of applying a current for warming to a motor to thereby increase an oil temperature when an eco-vehicle according to an exemplary embodiment of the present invention travels; and

fig. 6 is a graph showing test example results of an oil temperature increase test when the eco-friendly vehicle according to the exemplary embodiment of the present invention is parked.

Detailed Description

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As described above with reference to fig. 1, among the components of the power train of the hybrid vehicle, the electric oil pump 20 driven under the control of the oil pump control unit 21 is installed at a predetermined position of the transmission case covering the transmission 13, and an oil circulation path for cooling is formed in the motor 12 and the transmission 13.

Thus, when the oil for cooling and lubrication flows along the oil circulation paths of the motor 12 and the transmission 13 by operating the electric oil pump 20, the motor 12 and the transmission 13 are cooled.

However, in a low-temperature environment in which the temperature is less than the predetermined reference temperature, the viscosity of the oil circulated by operating the electric oil pump 20 increases. In order to circulate the oil having the increased viscosity, the output of the electric oil pump needs to be further increased. However, since the output pump of the electric oil has a fixed output according to the liter/minute (LPM) standard specification, there is a limitation in increasing the output for circulating the high viscosity oil.

Meanwhile, a driving motor applied to a hybrid vehicle or an electric vehicle mainly uses an Interior Permanent Magnet Synchronous Motor (IPMSM) configured to embed permanent magnets in a rotor.

In the case of a built-in permanent magnet synchronous motor, the rotational torque of the rotor is generated by the interaction between the rotating magnetic field generated by the three-phase current applied to the stator coil and the magnetic field of the permanent magnet of the rotor core.

Here, the amount of heat generated is proportional to the square of the current applied to the stator coil.

In view of the problem that there is a limit in increasing the output of the electric oil pump to a level at which high viscosity oil circulates and the problem that heat is generated by the current applied to the stator coil, the object of the present invention is: when the vehicle is stopped and driven under low-temperature environmental conditions, the temperature of the motor is raised by applying a current for temperature rise to the motor, and heat of the motor caused by the temperature rise is transferred to oil flowing through an oil circulation passage of the motor, thereby preventing the oil from increasing in viscosity in the low-temperature environment while maintaining the viscosity of the oil, thereby easily circulating the oil by the electric oil pump.

Referring to fig. 2, an oil temperature increasing system according to an exemplary embodiment of the present invention includes: an oil temperature detector 30 and a controller 40, the oil temperature detector 30 detecting a temperature of oil circulated to the motor 12 and the transmission 13 through the electric oil pump 20, the controller 40 receiving a detection signal of the oil temperature detector 30 and applying a current for warming to the motor 12 when the oil temperature is less than a predetermined reference temperature.

The oil temperature detector 30 may include an oil temperature sensor that detects the temperature of oil discharged from the electric oil pump 20 and supplied to the motor 12 and the transmission 13.

As shown in fig. 2, the controller 40 may be composed of a single integrated controller or a plurality of controllers including a hybrid controller 42 and a motor controller 43, the hybrid controller 42 being the highest controller for receiving the detection signal of the oil temperature detector 30 and the current gear signal of the transmission controller 41 to command the current of the motor 12, and the motor controller 43 controlling the current of the motor 12 according to the current command of the hybrid controller 42.

Specifically, the controller 40 is configured to receive a detection signal of the oil temperature detector 30 and a current gear signal of the transmission controller 41, and apply a current for warming to the motor 12 when the oil temperature is less than a predetermined reference temperature, and apply the current for warming in different manners at a P-range (when parking) and a forward (D) -range (when driving).

The controller 40 may be configured to receive a detection signal of the oil temperature detector 30 so as to apply a current for warming to the motor 12 when the oil temperature is less than a predetermined reference temperature, and to receive a current shift position signal of the transmission controller 41 so as to apply a d-axis current as a current for warming to the motor 12 when the shift position of the vehicle is the P-range.

At this time, if the d-axis current I is applied to the motor 12 while the vehicle is parked (the vehicle is parked through the P-range gear)_dDue to q-axis current I_qAt zero, the drive torque T of the motor 12 becomes zero according to the torque equation described in equation 1 below.

[ equation 1]

In equation 1 above, #_mI_qRepresenting the torque due to the field flux, (L)_d-L_q)I_dI_qRepresenting the torque caused by reluctance.

Thus, when the vehicle is stopped in the P range, only the d-axis current I is applied to the motor 12_dWhile q-axis current I_qIs zero. Therefore, the temperature of the motor 12 is likely to rise without generating the driving torque of the motor 12 that causes the motor 12 to rotate.

In other words, in a state where the motor 12 is not rotated by the d-axis current applied to the motor 12 (i.e., the d-axis current applied to the stator coil), heat is generated so that the temperature of the motor 12 is increased.

Subsequently, when heat of the motor 12 due to the temperature increase of the motor 12 is transferred to the oil flowing through the oil circulation passage 12-1 of the motor 12, the oil temperature is increased, thereby preventing the viscosity of the oil from increasing in a low temperature environment while maintaining the viscosity of the oil, thereby easily circulating the oil by the electric oil pump.

The driving torque of the motor 12 may be generated due to an error such as an angle of a resolver of the motor 12. However, since the magnitude of the torque that the parking gear can withstand in the P range is designed to be three or more times the maximum torque of the motor, even if the d-axis current I is applied to the motor when the parking (P) range is stopped_dDamage of the parking gear and movement of the vehicle can also be prevented.

In the P range, since there is a gap between teeth of the parking gear, an impact may occur due to generation of a transient torque of the motor, and as shown in fig. 4, when a d-axis current for warming up is applied to the motor, the controller 40 applies the current at a predetermined gradient for a predetermined period of time to reach a maximum d-axis current value, thereby easily preventing an impact phenomenon due to generation of the transient torque of the motor.

The controller 40 may be configured to receive a detection signal of the oil temperature detector 30 so as to apply a current for warming to the motor 12 when the oil temperature is less than a predetermined reference temperature, and receive a current gear signal of the transmission controller 41 so as to select an operating point at which the current is maximally applied on an equal torque line of a current map for driving the motor when the gear of the vehicle is the D gear.

The current map is map data contained in the controller for controlling the current (torque) of the motor.

For reference, as shown in fig. 5, a current map may be formed such that a plurality of equal torque lines T exist within a current limit range (shown by a current limit circle in fig. 5)₁、T₂、...T_maxAnd there are multiple operating points along each iso-torque line at which the current applied to the motor is varied.

The Maximum Torque Per Ampere (MTPA) in fig. 5 shows a curve with the maximum torque magnitude per unit current.

Therefore, when the oil temperature is less than the predetermined reference temperature and the shift position of the vehicle is the D range, the controller 40 changes the operating point of the motor to the operating point at which the current is maximally applied on the iso-torque line of the current map for driving the motor.

For example, when the controller controls the torque of the motor during vehicle running, the torque may be controlled using an operating point (an operating point that generates the minimum current and the maximum torque) existing along the MTPA curve. However, as shown by the arrows of fig. 5, the operating point is changed to an operating point at which the current can be maximally applied on the iso-torque line, i.e., an operating point at which the q-axis current can be decreased but the d-axis current can be increased to the maximum.

Thus, when the oil temperature is less than the predetermined reference temperature and the shift position of the vehicle is the D range, the controller 40 changes the operating point of the motor to the operating point at which the current is maximally applied on the iso-torque line of the current map for driving the motor, so that the current for warming up may be further applied to the motor 12. In addition, heat of the motor due to the temperature increase of the motor is transferred to the oil flowing through the oil circulation passage 12-1 of the motor, so that the oil temperature can be rapidly increased while the vehicle is running. Thus, it is possible to prevent the viscosity of the oil from rising in a low-temperature environment, and at the same time, maintain the viscosity of the oil, so that the oil can be easily circulated by the electric oil pump.

Here, the oil temperature increasing method for an eco-friendly vehicle according to the present invention will be described in sequence.

Fig. 3 is a flowchart illustrating an oil temperature increasing method for an eco-friendly vehicle according to an exemplary embodiment of the present invention.

First, the oil temperature detector 30 detects the temperature of oil circulated to the motor 12 and the transmission 13 by the electric oil pump, and then sends the oil temperature to the controller 40.

Subsequently, in step S101, the controller 40 checks whether the oil temperature is less than a predetermined reference temperature k.

Based on the check result, when the oil temperature is less than the predetermined reference temperature, the current gear signal of the transmission controller 41 is received, thereby identifying the current gear in steps S102 and S103.

When the current gear is identified as P gear in step 102, the controller 40 applies a d-axis current I to the electric machine 12_dAs a current for warming. More specifically, in step S104, the controller applies the current at a predetermined gradient for a predetermined period of time so as to reach the maximum d-axis current value.

Thus, when the vehicle is stopped in the P range, only the d-axis current I is applied to the motor 12_dWhile q-axis current I_qIs zero so that the driving torque of the motor causing the motor to rotate is not generated.

Thus, in a state where the motor is not rotated by the d-axis current applied to the motor 12 (i.e., the d-axis current applied to the stator coil), heat is generated, so that the temperature of the motor is increased.

Subsequently, when heat of the motor due to the temperature increase of the motor 12 is transferred to the oil flowing through the oil circulation passage 12-1 of the motor 12, the oil temperature is increased, thereby preventing the viscosity of the oil from increasing in a low temperature environment while maintaining the viscosity of the oil, thereby easily circulating the oil by the electric oil pump.

Referring to fig. 6 showing a test example of the present invention, it can be seen that when a d-axis current 280A is applied to the motor 12 at the P-gear, the motor temperature increases from 29 ℃ to 66 ℃ and the oil temperature increases from 28 ℃ to 45 ℃. This indicates that the oil temperature can be raised in a low temperature environment by only applying the d-axis current to the motor 12.

On the other hand, when it is recognized in step S103 that the current gear of the vehicle is the D range, the controller 40 changes the operating point of the motor 12 to the operating point at which the current is maximally applied on the iso-torque line of the current map for driving the motor 12 in step S105.

In this way, the controller 40 changes the operating point of the motor 12 to the operating point at which the current is maximally applied on the iso-torque line of the current map for driving the motor 12, so that the current for warming can be further applied to the motor 12. In addition, heat of the motor due to the temperature increase of the motor is transferred to the oil flowing through the oil circulation passage 12-1 of the motor, so that the oil temperature rapidly increases while the vehicle travels. Thus, the viscosity of the oil can be prevented from increasing in a low-temperature environment while maintaining the viscosity of the oil, so that the oil can be easily circulated by the electric oil pump.

After the step of increasing the oil temperature, the oil temperature is compared with the reference temperature k in step S106. Here, when the oil temperature detected within the predetermined period of time is equal to or greater than the predetermined reference temperature, the controller performs a control operation to stop the step of applying the current for warming to the motor in step S107.

Although the present invention has been described with reference to the specific embodiments shown in the drawings, it will be apparent to those skilled in the art that various changes and modifications may be made to the present invention without departing from the scope of the present invention described by the claims.