CN115771394A - Vehicle with a steering wheel - Google Patents

Abstract

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a vehicle capable of accurately estimating the temperature of a motor with a small number of parameters and improving energy efficiency. In order to solve the above problem, the present invention provides a vehicle including: a motor driving the vehicle; a vehicle speed sensor that detects a vehicle speed; cooling the material, cooling the motor; a cooling material temperature measuring unit that measures a temperature of the cooling material after cooling the motor; a motor temperature estimation unit that estimates a temperature of the motor based on the temperature of the cooling material; and a power saving execution unit that maintains or reduces the output of the motor when the estimated value of the temperature of the motor estimated by the motor temperature estimation unit is higher than a prescribed temperature; and the lower the vehicle speed, the lower the temperature of the motor estimated by the motor temperature estimating unit.

Description

Vehicle with a steering wheel

Technical Field

The present invention relates to a vehicle.

Background

Conventionally, there is known a technique of estimating a discharge amount of an oil pump, a vehicle speed, and a temperature of cooled oil, and estimating a temperature of a motor based on an operation state of the motor, thereby maintaining a function of the motor even when a failure occurs in a temperature sensor (for example, see patent document 1).

[ Prior Art document ]

(patent literature)

Patent document 1: japanese patent laid-open publication No. 2016-185050

Disclosure of Invention

[ problems to be solved by the invention ]

In the above-described conventional technique, the discharge amount of the oil pump, the vehicle speed, and the temperature of the cooled oil are estimated, and the temperature of the motor is estimated based on the operating state of the motor. In this case, since various estimation errors are large, it is difficult to accurately estimate the temperature of the motor. If the estimation error of the temperature of the motor is large, the function of the motor cannot be maintained accurately, and the energy efficiency may be reduced. Further, if the number of parameters is large, the logic for estimating the temperature of the motor becomes complicated, and the load on an Electronic Control Unit (ECU) for controlling the motor increases. Therefore, the consumption of energy required for controlling the motor also increases.

An object of the present invention is to provide a vehicle capable of accurately estimating the temperature of a motor with fewer parameters and achieving an improvement in energy efficiency.

[ means for solving problems ]

(1) A vehicle according to the present invention includes: a motor (e.g., an electric motor 1 described later) that drives a vehicle; a vehicle speed sensor (for example, a vehicle speed sensor 5 described later) that detects a vehicle speed; a cooling material (for example, ATF described later) for cooling the motor; a cooling material temperature measuring means (for example, a temperature sensor 3 described later) for measuring the temperature of the cooling material after cooling the motor; a motor temperature estimating means (for example, a motor temperature estimating unit 41 described later) for estimating the temperature of the motor based on the temperature of the cooling material; and a power saving executing unit (for example, a power saving executing unit 42) that maintains or reduces an output of the motor when the estimated value of the temperature of the motor estimated by the motor temperature estimating unit is higher than a predetermined temperature; and the lower the vehicle speed is, the lower the temperature of the motor is estimated by the motor temperature estimation unit.

(2) In the vehicle according to the above (1), preferably, the motor temperature estimating means estimates the temperature of the motor based on a vehicle speed-related line (for example, vehicle speed-related lines CL1 and CL2 described later) indicating a rate at which the temperature of the motor increases as the temperature of the cooling material increases.

(3) In the vehicle described in (2) above, it is preferable that the motor temperature estimation means has at least two types of information of the vehicle speed-related line, one type being that when the vehicle speed is equal to or higher than a predetermined speed, and one type being that when the vehicle speed is lower than the predetermined speed, the ratio of the vehicle speed-related line (for example, a vehicle speed-related line CL2 described later) when the vehicle speed is lower than the predetermined speed is smaller than the ratio of the vehicle speed-related line (for example, a vehicle speed-related line CL1 described later) when the vehicle speed is equal to or higher than the predetermined speed.

(4) A vehicle according to the present invention includes: a motor (e.g., an electric motor 1 described later) that drives a vehicle; an inclination sensor (for example, an inclination sensor 6 described later) that detects an inclination of the vehicle in a climbing state; a cooling material (for example, ATF described later) for cooling the motor; a cooling material temperature measuring unit (for example, a temperature sensor 3) that measures a temperature of the cooling material after cooling the motor; a motor temperature estimating means (for example, a motor temperature estimating unit 41A described later) for estimating the temperature of the motor based on the temperature of the cooling material; and a power saving execution unit (for example, a power saving execution unit 42 described later) that maintains or reduces an output of the motor when the estimated value of the temperature of the motor estimated by the motor temperature estimation unit is higher than a predetermined temperature; and the lower the gradient of the vehicle is, the lower the temperature of the motor is estimated by the motor temperature estimation unit.

(5) In the vehicle described in (4) above, it is preferable that the motor temperature estimation unit estimates the temperature of the motor based on a vehicle inclination correlation line (for example, vehicle inclination correlation lines CL3 and CL4 described later) indicating a rate at which the temperature of the motor increases as the temperature of the cooling material increases.

In the vehicle described in (5), the motor temperature estimation means may include at least two types of information on the vehicle inclination related line, one of which is the proportion of the vehicle inclination related line (for example, a vehicle inclination related line CL4 described later) when the inclination of the vehicle is lower than a predetermined angle when the inclination of the vehicle is equal to or higher than the predetermined angle and the other of which is lower than the predetermined angle, and which is smaller than the proportion of the vehicle inclination related line (for example, a vehicle inclination related line CL3 described later) when the inclination of the vehicle is equal to or higher than the predetermined angle.

(effect of the invention)

According to the above (1), the temperature of the motor can be accurately estimated using only the parameters of the vehicle speed and the temperature of the cooling material, and improvement in energy efficiency can be achieved. Since the temperature of the motor can be accurately estimated based on the vehicle speed characteristic of the vehicle, unnecessary power saving can be avoided and the sense of discomfort of the driver can be suppressed. Since it is not necessary to provide a thermistor or the like to the motor, cost reduction can be achieved.

According to the above (2), by estimating the temperature of the motor based on the preset vehicle speed correlation line suitable for the vehicle, the load of the ECU controlling the motor can be further reduced.

According to the above (3), the temperature of the motor is estimated based on any one of the two types of vehicle speed correlation lines different in proportion according to the vehicle speed, and therefore, the estimation accuracy of the temperature can be improved, and unnecessary power saving can be further reliably avoided.

According to the above (4), the temperature of the motor can be accurately estimated using only the parameters of the slope of the vehicle and the temperature of the cooling material, and improvement in energy efficiency can be achieved. The temperature of the motor can be estimated more accurately according to the slope of the vehicle, and therefore, unnecessary power saving can be avoided and the sense of discomfort of the driver can be suppressed. Since it is not necessary to provide a temperature sensor in the motor, cost reduction can be achieved.

According to the above (5), the load on the ECU that controls the motor can be further reduced by setting the vehicle inclination related line suitable for the vehicle in advance and estimating the temperature of the motor based on the vehicle inclination related line.

According to the above (6), the temperature of the motor is estimated based on any one of the two types of vehicle inclination related lines different in proportion according to the inclination of the vehicle, and therefore, the estimation accuracy of the temperature can be improved, and unnecessary power saving can be further reliably avoided.

Drawings

Fig. 1 is a block diagram schematically showing a configuration related to motor control of a vehicle according to a first embodiment.

Fig. 2 is a graph showing information on a vehicle speed-related line of the vehicle according to the first embodiment.

Fig. 3 is a flowchart illustrating control of the ECU of the vehicle according to the first embodiment.

Fig. 4 is a functional block diagram illustrating a motor temperature estimating unit of a vehicle according to the first embodiment.

Fig. 5 is a block diagram schematically showing a configuration related to motor control of the vehicle according to the second embodiment.

Fig. 6 is a graph showing information on a vehicle inclination related line of the vehicle according to the second embodiment.

Fig. 7 is a flowchart illustrating control of the ECU of the vehicle according to the second embodiment.

Fig. 8 is a functional block diagram illustrating a motor temperature estimating unit of a vehicle according to a second embodiment.

Detailed Description

[ first embodiment ]

Hereinafter, the vehicle according to the first embodiment will be described in detail with reference to the drawings. Fig. 1 is a block diagram schematically showing a configuration related to motor control of a vehicle according to a first embodiment. As shown in fig. 1, the vehicle is equipped with at least one electric motor 1 that drives the vehicle. The vehicle may include an internal combustion engine (not shown) for driving the vehicle, in addition to the electric motor 1.

The electric motor 1 is, for example, a three-phase ac synchronous motor, and has a structure in which a rotor 12 having a motor magnet 12a is rotatably housed inside a stator 11 having a motor winding 11a. The electric motor 1 is mounted on a vehicle such that the rotation axis direction of the rotor 12 is oriented in the horizontal direction. The electric motor 1 drives the vehicle by rotating the rotor 12 at a rotation speed according to the magnitude of a drive current sent from an ECU4, which will be described later, provided in the vehicle to the motor winding 11a of the stator 11. Further, the electric motor 1 in fig. 1 schematically shows a half section in the radial direction (the vertical direction in fig. 1) of the electric motor 1.

The electric motor 1 is provided with a cooling device 2 for cooling the electric motor 1. The cooling device 2 cools the electric motor 1 by dropping a cooling material made of liquid onto the stator 11. The cooling device 2 includes: a dropper 21 for dropping a cooling material, a cooling material inflow pipe 22 for allowing the cooling material to flow into the dropper 21, a cooling material outflow pipe 23 for allowing the cooling material having cooled the stator 11 to flow out of the electric motor 1, a cooling material tank 24 for collecting and storing the cooling material, and a pump 25. The drop tube 21 is disposed above the electric motor 1.

The cooling device 2 supplies the coolant in the coolant tank 24 to the drop tube 21 through the coolant inflow tube 22 by driving the pump 25. The cooling material supplied to the drip pipe 21 is dripped from the plurality of holes of the drip pipe 21 to the stator 11 of the electric motor 1, thereby cooling the stator 11. The cooling material having cooled the stator 11 is recovered and stored in a cooling material storage tank 24 through a cooling material outflow pipe 23.

The cooling material used in the cooling device 2 is not particularly limited, and a liquid capable of cooling the electric motor 1 may be used. The vehicle of the present embodiment uses the Automatic Transmission hydraulic oil, that is, the Automatic Transmission Fluid (ATF) as the cooling material.

A temperature sensor 3 is provided in the middle of the coolant outflow pipe 23. The temperature sensor 3 functions as a coolant temperature measuring means that measures the temperature of the coolant after cooling the electric motor 1. The temperature value of the cooling material measured by the temperature sensor 3 is sent to an ECU4 described later.

An Electronic Control Unit (ECU) 4 is a motor Control device that controls driving of the electric motor 1. The ECU4 includes a motor temperature estimation unit 41, a power saving execution unit 42, and a motor drive unit 43. The ECU4 receives a vehicle speed value detected by a vehicle speed sensor 5. The vehicle speed sensor 5 is provided on the vehicle and detects the vehicle speed.

The motor temperature estimating unit 41 receives the temperature value of the cooling material measured by the temperature sensor 3. The motor temperature estimating unit 41 functions as a motor temperature estimating unit that estimates the temperature of the electric motor 1 based on the temperature of the cooling material. A more detailed description of the motor temperature estimating section 41 will be described later.

The power saving execution unit 42 functions as power saving execution means for maintaining or reducing the output of the electric motor 1 when the estimated value of the temperature of the electric motor 1 estimated by the motor temperature estimation unit 41 is higher than a predetermined temperature. That is, if the electric motor 1 is overheated, demagnetization or degaussing of the motor magnet 12a may occur. The power saving execution unit 42 monitors whether or not the estimated value of the temperature of the electric motor 1 exceeds a predetermined temperature, and determines whether or not the electric motor 1 is overheated. When the power saving execution part 42 judges that the electric motor 1 is overheated, a power saving signal instructing to maintain the output of the electric motor 1 at the current output or lower than the current output is output to the motor drive part 43 regardless of the opening degree of the accelerator operated by the driver.

The predetermined temperature compared with the estimated value of the temperature of the electric motor 1 in the power saving execution unit 42 is a threshold value for determining whether or not the electric motor 1 is overheated. The threshold value is set in advance in the power saving execution unit 42 as a management temperature of a portion of the electric motor 1 where the overheat of the electric motor 1 can be determined. The management temperature is appropriately set according to the location of the electric motor 1.

Examples of the portion of the electric motor 1 where the overheat of the electric motor 1 can be determined include the motor magnet 12a of the rotor 12 and the motor winding 11a of the stator 11. The power saving execution unit 42 of the first embodiment uses the motor magnet 12a of the rotor 12 as a portion of the electric motor 1 where it can be determined that the electric motor 1 is overheated. The power saving execution unit 42 compares an estimated value of the temperature of the motor magnet 12a (hereinafter, referred to as a motor magnet temperature) with a predetermined temperature. In this case, the predetermined temperature is a control temperature of the motor magnet 12 a.

The motor drive unit 43 outputs a drive current for driving the electric motor 1 to the motor winding 11a of the stator 11 of the electric motor 1 in accordance with the opening degree of the accelerator operated by the driver. When the power saving signal is input from the power saving execution unit 42, the motor drive unit 43 controls the drive current output to the electric motor 1 so that the output of the electric motor 1 is maintained at the current output or is lower than the current output regardless of the opening degree of the accelerator.

Next, the motor temperature estimating unit 41 of the first embodiment will be further described. The temperature of the coolant that cools the electric motor 1 is related to the temperature of the portion of the electric motor 1 where the control temperature is set. That is, the higher the temperature of the cooling material, the higher the temperature of the portion of the electric motor 1. The motor temperature estimation unit 41 of the first embodiment estimates the motor magnet temperature based on the temperature value of the cooling material sent from the temperature sensor 3 after the start of driving the electric motor 1. Since the parameter used in the estimation is only the temperature of the cooling material, the motor temperature estimation portion 41 can easily and accurately estimate the motor magnet temperature. As a result, the function of the electric motor 1 is accurately maintained, and the energy efficiency is improved. Since it is not necessary to provide a thermistor in the electric motor 1, the cost can be reduced. Since the logic for estimating the temperature can be simplified, the load on the ECU4 is reduced.

The lower the vehicle speed, the lower the motor magnet temperature of the electric motor 1 is estimated by the motor temperature estimation unit 41. Generally, if the rotor 12 rotates at a high speed (high vehicle speed), the loss of the motor magnet 12a increases, and heat is generated due to deterioration of the iron loss. Therefore, the tendency of the correlation between the motor magnet temperature and the coolant temperature changes depending on the magnitude of the vehicle speed, and the motor magnet temperature decreases as the vehicle speed decreases as compared with the case where the vehicle speed increases. Therefore, the lower the motor magnet temperature is estimated by the lower the vehicle speed, the more accurately the motor magnet temperature can be estimated from the vehicle speed characteristics of the vehicle. Since unnecessary power saving is prevented from being performed when the vehicle speed is low, the sense of discomfort of the driver is also suppressed.

The motor temperature estimating section 41 estimates the motor magnet temperature based on, for example, two types of vehicle speed correlation lines CL1, CL2 showing the correlation between the cooling material temperature and the motor magnet temperature as shown in fig. 2. The vehicle speed correlation lines CL1 and CL2 are data of a calculation formula indicating a ratio of the motor magnet temperature to increase with an increase in the temperature of the cooling material. The calculation formula represented by the vehicle speed correlation lines CL1, CL2 is created based on the result of pre-modeling the correlation between the cooling material temperature and the motor magnet temperature, and is provided in the motor temperature estimation section 41. The motor temperature estimating unit 41 can estimate the motor magnet temperature of the electric motor 1 more easily based on the information on the vehicle speed correlation lines CL1 and CL2. Since the temperature can be estimated by calculation alone without MAP or the like, the load on the ECU4 is also reduced.

The two types of vehicle speed correlation lines CL1, CL2 represent calculation formulas that differ according to the vehicle speed. The vehicle speed-related line CL1 calculates the motor magnet temperature (Ym 1) with respect to the coolant temperature (X) by using the calculation formula of a1X + b 1. The vehicle speed-related line CL2 calculates the motor magnet temperature (Ym 2) with respect to the coolant temperature (X) by using the calculation formula of a2X + b 2. The ratio of the motor magnet temperature (Ym 2) to the coolant temperature (X) indicated by the vehicle speed-related line CL2 is smaller than the ratio of the motor magnet temperature (Ym 1) to the coolant temperature (X) indicated by the vehicle speed-related line CL1.

The motor temperature estimating section 41 selects any one of the two types of vehicle speed-related lines CL1, CL2 as a vehicle speed-related line used when estimating the motor magnet temperature, based on the vehicle speed value acquired from the vehicle speed sensor 5. Specifically, the motor temperature estimating unit 41 selects one of the two types of vehicle speed correlation lines CL1 and CL2 according to whether the vehicle speed value obtained from the vehicle speed sensor 5 is higher or lower than a predetermined speed when estimating the motor magnet temperature. Since the motor magnet temperature can be estimated using the vehicle speed correlation line having the best correlation coefficient according to the vehicle speed, the estimation accuracy of the temperature of the electric motor 1 can be further improved.

The threshold value, that is, the prescribed speed, which determines the vehicle speed-related line used in estimating the motor magnet temperature is appropriately determined in accordance with the specifications of the vehicle and the electric motor 1, etc., and is provided in advance in the motor temperature estimating section 41. The prescribed speed of the motor temperature estimating unit 41 of the first embodiment is set to 150km/h. That is, the motor temperature estimating section 41 selects either one of the two types of vehicle speed correlation lines CL1, CL2 according to whether the vehicle speed value acquired from the vehicle speed sensor 5 is 150km/h or more or less than 150km/h. Specifically, the motor temperature estimating section 41 uses the vehicle speed correlation line CL1 in estimating the motor magnet temperature when the vehicle speed value obtained from the vehicle speed sensor 5 is 150km/h or more, and uses the vehicle speed correlation line CL2 in estimating the motor magnet temperature when the vehicle speed value obtained from the vehicle speed sensor 5 is less than 150km/h.

Next, an example of control according to the first embodiment based on temperature estimation of the electric motor 1 by the ECU4 in the vehicle will be described with reference to the flowchart of fig. 3. The estimation operation of the temperature of the electric motor 1 by the ECU4 is performed at a prescribed cycle, for example, after the vehicle starts running while the electric motor 1 is driven.

If the electric motor 1 is driven and the vehicle starts running, the ECU4 acquires a vehicle speed value from the vehicle speed sensor 5 (step S1), and determines whether or not the vehicle speed value is 150km/h or more in the motor temperature estimating section 41 (step S2).

When the acquired vehicle speed value is 150km/h or more (step S2; yes), the ECU4 then acquires the temperature value of the cooling material measured by the temperature sensor 3 (step S3), and estimates the motor magnet temperature in the motor temperature estimation unit 41 based on the temperature value (step S4).

In detail, since the vehicle speed value acquired from the vehicle speed sensor 5 is 150km/h or more, the motor temperature estimating section 41 selects the vehicle speed correlation line CL1 from two types of preset vehicle speed correlation lines CL1, CL2 shown in fig. 2. As shown in fig. 4, the motor temperature estimating unit 41 obtains an estimated value (Ym 1) of the motor magnet temperature by inputting the temperature value (ATF temperature) of the coolant into a calculation formula X indicated by a vehicle speed correlation line CL1, multiplying the result by an inclination (a 1), and adding an intercept (b 1). The motor temperature estimation unit 41 outputs the obtained estimated value (Ym 1) of the motor magnet temperature to the power saving execution unit 42.

On the other hand, when the acquired vehicle speed value is less than 150km/h in step S2 (step S2; NO), the ECU4 acquires the temperature value of the cooling material measured by the temperature sensor 3 (step S5), and estimates the motor magnet temperature in the motor temperature estimation unit 41 based on the temperature value (step S6).

In detail, since the vehicle speed value acquired from the vehicle speed sensor 5 is lower than 150km/h, the motor temperature estimating section 41 selects the vehicle speed correlation line CL2 from two types of preset vehicle speed correlation lines CL1, CL2 shown in fig. 2. As shown in fig. 4, the motor temperature estimating unit 41 obtains an estimated value (Ym 2) of the motor magnet temperature by inputting the temperature value (ATF temperature) of the coolant into a calculation formula X indicated by a vehicle speed correlation line CL2, multiplying the result by a slope (a 2), and adding an intercept (b 2). The motor temperature estimation unit 41 outputs the obtained estimated value (Ym 2) of the motor magnet temperature to the power saving execution unit 42.

After the estimated value (Ym 1 or Ym 2) of the motor magnet temperature is output from the motor temperature estimating unit 41, the ECU4 determines whether the estimated value (Ym 1 or Ym 2) of the motor magnet temperature exceeds a preset motor magnet management temperature in the power saving executing unit 42 (step S7). In the power saving execution unit 42 of the first embodiment, the motor magnet management temperature is set to 165 ℃.

Specifically, the power saving execution unit 42 compares the estimated value (Ym 1 or Ym 2) of the motor magnet temperature obtained by the motor temperature estimation unit 41 with the motor magnet management temperature, and as a result, when it is determined that the estimated value (Ym 1 or Ym 2) of the motor magnet temperature exceeds the motor magnet management temperature (step S7; yes), instructs the motor drive unit 43 to maintain the output of the electric motor 1 at the current output or to decrease the output of the electric motor 1 (step S8). Thus, the motor drive unit 43 outputs a drive current for maintaining or reducing the output of the electric motor 1 to the motor winding 11a of the electric motor 1. As a result, the output of the electric motor 1 is maintained at the current output or is reduced to a predetermined output regardless of the opening degree of the accelerator operated by the driver.

In step S7, when the power saving execution unit 42 determines that the estimated value (Ym 1 or Ym 2) of the motor magnet temperature does not exceed the motor magnet management temperature (step S7; no), power saving is not instructed to the motor drive unit 43. Therefore, the electric motor 1 is rotationally driven at a speed corresponding to the opening degree of the accelerator operated by the driver.

As described above, the vehicle according to the first embodiment includes: an electric motor 1 that drives a vehicle; a vehicle speed sensor 5 for detecting a vehicle speed; a cooling material (ATF) that cools the electric motor 1; a temperature sensor 3 that measures the temperature of the cooling material after cooling the electric motor 1; a motor temperature estimation unit 41 that estimates the temperature of the electric motor 1 based on the temperature of the cooling material; a power saving execution unit 42 that maintains or reduces the output of the electric motor 1 when the estimated value of the temperature of the electric motor 1 estimated by the motor temperature estimation unit 41 is higher than a predetermined temperature; the motor temperature estimating unit 41 estimates that the temperature of the electric motor 1 is lower as the vehicle speed is lower. Accordingly, the temperature of the electric motor 1 can be accurately estimated using only the vehicle speed and the temperature of the cooling material, and an improvement in energy efficiency can be achieved. Since the temperature of the electric motor 1 can be accurately estimated according to the vehicle speed characteristics of the vehicle, unnecessary power saving can be avoided and the sense of discomfort of the driver can be suppressed. Since it is not necessary to provide a thermistor or the like in the electric motor 1, cost reduction can be achieved.

The motor temperature estimating section 41 in the first embodiment estimates the temperature of the electric motor 1 based on vehicle speed related lines CL1, CL2, which indicate the rate at which the temperature of the electric motor 1 increases as the temperature of the cooling material increases. Accordingly, since the temperature of the electric motor 1 is estimated based on the preset vehicle speed correlation line suitable for the vehicle, the load of the ECU4 that controls the electric motor 1 can be further reduced.

The motor temperature estimating section 41 in the first embodiment has information of two types of vehicle speed correlation lines CL1, CL2 when the vehicle speed is above a prescribed speed and below the prescribed speed. The proportion of the vehicle speed correlation line CL2 when the vehicle speed is lower than the predetermined speed is smaller than the proportion of the vehicle speed correlation line CL1 when the vehicle speed is higher than the predetermined speed. Accordingly, the temperature of the electric motor 1 is estimated based on any one of the two types of vehicle speed correlation lines CL1, CL2 different in proportion from each other in accordance with the vehicle speed, and therefore, the accuracy of estimating the temperature can be further improved, and unnecessary power saving can be more reliably avoided.

[ second embodiment ]

Next, a vehicle according to a second embodiment will be described in detail with reference to the drawings. Fig. 5 is a block diagram of a schematic configuration related to motor control of the vehicle according to the second embodiment. Since the same reference numerals as those in the block diagram shown in fig. 1 denote the same components, the description thereof will be referred to above and omitted below.

The ECU4A in the second embodiment is a motor control device that controls the driving of the electric motor 1. The ECU4A includes a motor temperature estimation unit 41A, a power saving execution unit 42, and a motor drive unit 43. The ECU4A receives as input the tilt angle value of the vehicle detected by the tilt sensor 6. The inclination sensor 6 is provided on the vehicle and detects the inclination of the vehicle in a climbing state. Specifically, the inclination sensor 6 detects an upward inclination of the vehicle in the traveling direction when the vehicle travels uphill with reference to a horizontal plane.

The temperature value of the cooling material measured by the temperature sensor 3 is input to the motor temperature estimation unit 41A. The motor temperature estimating section 41A functions as a motor temperature estimating unit that estimates the temperature of the electric motor 1 based on the temperature of the cooling material. Further detailed description of the motor temperature estimating section 41A will be described later.

The power saving execution unit 42 of the second embodiment uses the motor winding 11a of the stator 11 as a portion of the electric motor 1 where it can be determined that the electric motor 1 is overheated. The power saving execution unit 42 compares an estimated value of the temperature of the motor winding 11a (hereinafter referred to as a motor winding temperature) with a predetermined temperature. In this case, the predetermined temperature is a control temperature of the motor winding 11a.

Next, the motor temperature estimating unit 41A of the second embodiment will be further described. The motor temperature estimation unit 41A of the second embodiment estimates the motor winding temperature based on the temperature value of the cooling material sent from the temperature sensor 3 after the start of driving the electric motor 1. Since the measured temperature is only the temperature of the cooling material, the motor temperature estimating section 41A can easily and accurately estimate the motor winding temperature. As a result, the function of the electric motor 1 is accurately maintained, and the energy efficiency is improved. Since it is not necessary to provide a thermistor in the electric motor 1, the cost can be reduced. Since the logic for estimating the temperature is simplified, the load on the ECU4A is reduced.

The motor temperature estimating section 41A estimates that the motor winding temperature of the electric motor 1 is lower as the inclination of the vehicle is smaller. Generally, if the inclination angle of the vehicle increases due to the vehicle climbing, the loss increases at a low vehicle speed (low-speed rotation) and high torque, and heat is generated due to deterioration of the copper loss. Therefore, the tendency of the correlation between the motor winding temperature and the cooling material temperature varies depending on the tilt angle of the vehicle, and the motor winding temperature is lower when the tilt angle of the vehicle is small than when the tilt angle is large. Therefore, the lower the inclination angle of the vehicle is, the lower the motor winding temperature is estimated, so that the motor winding temperature can be accurately estimated from the inclination angle of the vehicle. When the inclination angle of the vehicle is small, since unnecessary power saving is avoided from being performed, the sense of discomfort of the driver is also suppressed.

The motor temperature estimation section 41A estimates the motor winding temperature based on, for example, two types of vehicle inclination related lines CL3, CL4 showing the correlation of the cooling material temperature and the motor winding temperature shown in fig. 6. The vehicle inclination related lines CL3, CL4 are data of a calculation formula representing a proportion of the motor winding temperature that increases with the temperature rise of the cooling material. The calculation formula represented by the vehicle inclination correlation lines CL3, CL4 is created based on the result of pre-modeling the correlation of the cooling material temperature and the motor winding temperature, and is set in the motor temperature estimation section 41A. The motor temperature estimation section 41A can estimate the motor winding temperature of the electric motor 1 more easily by the information based on such vehicle inclination related lines CL3, CL4. Since the temperature can be estimated by calculation without MAP or the like, the load on the ECU4A is further reduced.

The two types of vehicle inclination related lines CL3, CL4 represent calculation formulas that differ according to the inclination angle of the vehicle. The vehicle inclination correlation line CL3 calculates the motor winding temperature (Yc 1) with respect to the coolant temperature (X) using the calculation formula of a1X + b 1. The vehicle inclination related line CL4 calculates the motor winding temperature (Yc 2) with respect to the coolant temperature (X) using the calculation formula of a2X + b 2. The ratio of the motor winding temperature (Yc 2) to the cooling material temperature (X) indicated by the vehicle inclination-related line CL4 is smaller than the ratio of the motor winding temperature (Yc 1) to the cooling material temperature (X) indicated by the vehicle inclination-related line CL3.

The motor temperature estimating section 41A selects either one of the two types of vehicle inclination related lines CL3, CL4 as the vehicle inclination related line used in estimating the motor winding temperature, based on the slope value acquired from the inclination sensor 6. Specifically, the motor temperature estimation unit 41A selects any one of the two types of vehicle inclination related lines CL3, CL4 in accordance with whether the value of the inclination angle obtained from the inclination sensor 6 is higher or lower than a predetermined angle when estimating the motor winding temperature. Since the motor winding temperature can be estimated using the vehicle inclination correlation line having the optimum correlation coefficient according to the inclination angle of the vehicle, the estimation accuracy of the temperature of the electric motor 1 can be further improved.

The threshold value, that is, the prescribed angle, of the vehicle inclination related line that is used in estimating the motor winding temperature is determined appropriately in accordance with the specifications of the vehicle and the electric motor 1, etc., and is preset in the motor temperature estimating section 41A. The motor temperature estimating unit 41A of the second embodiment is set to 12.4deg. That is, the motor temperature estimating section 41A selects either one of the two types of vehicle inclination related lines CL3, CL4 depending on whether the value of the inclination of the vehicle acquired from the inclination sensor 6 is 12.4deg or more or less than 12.4deg. Specifically, when the value of the slope of the vehicle acquired from the slope sensor 6 is 12.4deg or more, the motor temperature estimation section 41A uses the vehicle slope correlation line CL3 in estimating the motor winding temperature, and when the value of the slope of the vehicle acquired from the slope sensor 6 is less than 12.4deg, the vehicle slope correlation line CL4 in estimating the motor winding temperature.

Next, an example of control according to the second embodiment based on temperature estimation of the electric motor 1 by the ECU4A in the vehicle will be described with reference to the flowchart of fig. 7. The estimation operation of the temperature of the electric motor 1 by the ECU4A is performed at a predetermined cycle, for example, after the electric motor 1 is driven and the vehicle starts running.

If the electric motor 1 is driven and the vehicle starts running, the ECU4A acquires a vehicle slope value from the slope sensor 6 (step S11), and the motor temperature estimation unit 41A determines whether or not the vehicle slope value is 12.4deg or more (step S12).

Here, when the obtained vehicle slope value is 12.4deg or more (step S12; yes), then the ECU4A obtains the temperature value of the cooling material measured by the temperature sensor 3 (step S13), and estimates the motor winding temperature in the motor temperature estimation portion 41A based on the temperature value (step S14).

In detail, since the vehicle inclination value acquired from the inclination sensor 6 is 12.4deg or more, the motor temperature estimating section 41A selects the vehicle inclination related line CL3 from two types of vehicle inclination related lines CL3, CL4 shown in fig. 6, which are preset. As shown in fig. 8, the motor temperature estimation unit 41A obtains an estimated value (Yc 1) of the motor winding temperature by inputting the temperature value (ATF temperature) of the coolant into a calculation formula X indicated by a vehicle inclination correlation line CL3, multiplying the result by an inclination (a 1), and adding an intercept (b 1). The motor temperature estimation unit 41A outputs the obtained estimated value (Yc 1) of the motor winding temperature to the power saving execution unit 42.

On the other hand, when the obtained vehicle slope value is lower than 12.4deg in step S12 (step S12; NO), the ECU4A obtains the temperature value of the cooling material measured by the temperature sensor 3 (step S15), and based on the temperature value, the motor winding temperature is estimated in the motor temperature estimating section 41A (step S16).

In detail, since the value of the vehicle inclination angle acquired from the inclination sensor 6 is lower than 12.4deg, the motor temperature estimating section 41A selects the vehicle inclination related line CL4 from the two types of vehicle inclination related lines CL3, CL4 shown in fig. 6, which are preset. As shown in fig. 8, the motor temperature estimation unit 41A obtains an estimated value (Yc 2) of the motor winding temperature by inputting the temperature value (ATF temperature) of the coolant into a calculation formula X indicated by a vehicle inclination correlation line CL4, multiplying the result by a slope (a 2), and adding an intercept (b 2). The motor temperature estimation unit 41A outputs the obtained estimated value (Yc 2) of the motor winding temperature to the power saving execution unit 42.

After the estimated value (Yc 1 or Yc 2) of the motor winding temperature is output from the motor temperature estimating section 41A, the ECU4A determines whether or not the estimated value (Yc 1 or Yc 2) of the motor winding temperature exceeds a preset motor winding management temperature in the power saving executing section 42 (step S17). In the power saving execution unit 42 of the second embodiment, the motor magnet management temperature is set to 195 ℃.

Specifically, the power saving execution unit 42 compares the estimated value (Yc 1 or Yc 2) of the motor winding temperature obtained by the motor temperature estimation unit 41A with the motor winding management temperature, and as a result, when it is determined that the estimated value (Yc 1 or Yc 2) of the motor winding temperature exceeds the motor winding management temperature (step S17; yes), instructs the motor drive unit 43 to maintain the output of the electric motor 1 at the current output or to decrease the output of the electric motor 1 (step S18). Thereby, the motor drive unit 43 outputs a drive current for maintaining or reducing the output of the electric motor 1 to the motor winding 11a of the electric motor 1. As a result, the output of the electric motor 1 is maintained at the current output or is reduced to a predetermined output regardless of the opening degree of the accelerator operated by the driver.

In step S17, when the power saving execution unit 42 determines that the estimated value (Yc 1 or Yc 2) of the motor winding temperature does not exceed the motor winding management temperature (step S17; no), power saving is not instructed to the motor drive unit 43. Therefore, the electric motor 1 is rotationally driven at a speed corresponding to the opening degree of the accelerator operated by the driver.

As described above, the vehicle according to the second embodiment includes: an electric motor 1 that drives a vehicle; an inclination sensor 6 that detects the inclination of the vehicle in the climbing state; a cooling material (ATF) that cools the electric motor 1; a temperature sensor 3 that measures the temperature of the cooling material after cooling the electric motor 1; a motor temperature estimation unit 41A that estimates the temperature of the electric motor 1 based on the temperature of the cooling material; and a power saving execution part 42 for maintaining or reducing the output of the electric motor 1 when the estimated value of the temperature of the electric motor 1 estimated by the motor temperature estimation part 41A is higher than a predetermined temperature; the motor temperature estimating unit 41A estimates that the temperature of the electric motor 1 is lower as the gradient of the vehicle is smaller. Accordingly, the temperature of the electric motor 1 can be accurately estimated using only the parameters of the slope of the vehicle and the temperature of the cooling material, and improvement in energy efficiency can be achieved. Since the temperature of the electric motor 1 can be accurately estimated from the slope of the vehicle, unnecessary power saving can be avoided and the sense of discomfort of the driver can be suppressed. Since it is not necessary to provide a thermistor or the like to the electric motor 1, cost reduction can be achieved.

The motor temperature estimation portion 41A of the second embodiment estimates the temperature of the electric motor 1 based on the vehicle inclination related line indicating the rate at which the temperature of the electric motor 1 increases as the temperature of the cooling material increases. Accordingly, since the temperature of the electric motor 1 is estimated based on the vehicle inclination correlation line that is preset to suit the inclination of the vehicle, the load of the ECU4A that controls the electric motor 1 can be further reduced.

The motor temperature estimating unit 41A of the second embodiment has information of at least two types of vehicle inclination related lines CL3, CL4 when the inclination of the vehicle is above a predetermined angle and below the predetermined angle. The proportion of the vehicle inclination correlation line CL4 when the inclination of the vehicle is lower than the predetermined angle is smaller than the proportion of the vehicle inclination correlation line CL3 when the inclination of the vehicle is equal to or higher than the predetermined angle. Accordingly, the temperature of the electric motor 1 is estimated based on either one of the two types of vehicle inclination related lines CL3, CL4 different in proportion from the gradient of the vehicle, the estimation accuracy of the temperature can be improved, and unnecessary power saving can be further reliably avoided.

Reference numerals

1: electric motor

3: temperature sensor (Cooling material temperature measuring unit)

5: vehicle speed sensor

6: tilt sensor

41,41A: motor temperature estimation part (Motor temperature estimation unit)

42: power saving execution unit

CL1, CL2: vehicle speed correlation line

CL3, CL4: vehicle inclination related line

Claims (6)

1. A vehicle is provided with:

a motor driving the vehicle;

a vehicle speed sensor for detecting a vehicle speed;

a cooling material for cooling the motor;

a cooling material temperature measuring unit that measures a temperature of the cooling material after the motor is cooled;

a motor temperature estimating unit that estimates a temperature of the motor based on the temperature of the cooling material; and a (C) and (D) and,

an electricity-saving execution unit that maintains or reduces the output of the motor when the estimated value of the temperature of the motor estimated by the motor temperature estimation unit is higher than a predetermined temperature; and also,

the lower the vehicle speed, the lower the temperature of the motor estimated by the motor temperature estimating unit.

2. The vehicle according to claim 1, wherein,

the motor temperature estimating unit estimates the temperature of the motor based on a vehicle speed correlation line indicating a rate at which the temperature of the motor increases as the temperature of the cooling material increases.

3. The vehicle according to claim 2,

the motor temperature estimating unit has at least two types of information of the vehicle speed-related line, one when the vehicle speed is above a prescribed speed, one when below the prescribed speed,

the ratio of the vehicle speed correlation line when the vehicle speed is lower than the predetermined speed is smaller than the ratio of the vehicle speed correlation line when the vehicle speed is equal to or higher than the predetermined speed.

4. A vehicle is provided with:

a motor driving the vehicle;

an inclination sensor that detects an inclination of the vehicle in a climbing state;

a cooling material for cooling the motor;

a cooling material temperature measuring unit that measures a temperature of the cooling material after the motor is cooled;

a motor temperature estimation unit that estimates a temperature of the motor based on the temperature of the cooling material; and a process for the preparation of a coating,

a power saving execution unit that maintains or reduces an output of the motor when the estimated value of the temperature of the motor estimated by the motor temperature estimation unit is higher than a predetermined temperature; and also,

the lower the gradient of the vehicle is, the lower the temperature of the motor is estimated by the motor temperature estimation unit.

5. The vehicle according to claim 4,

the motor temperature estimation unit estimates the temperature of the motor based on a vehicle inclination correlation line indicating a ratio of the temperature of the motor rising with the temperature rise of the cooling material.

6. The vehicle according to claim 5, wherein,

the motor temperature estimating unit has at least two types of information of the vehicle inclination related line, one being when a gradient of the vehicle is above a prescribed angle and the other being below the prescribed angle,

the ratio of the vehicle inclination correlation line when the inclination of the vehicle is lower than the predetermined angle is smaller than the ratio of the vehicle inclination correlation line when the inclination of the vehicle is equal to or greater than the predetermined angle.

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