Electric vehicle and method for controlling it to preheat a lubricant

Abstract

Electric vehicle comprising: a power storage device (54) configured to store electrical power used to drive the electric vehicle; a first electric motor (MG1, MG2) configured to receive electrical power from the power storage device (54), the first electric motor (MG1, MG2) generating power;a power transmission device (30) provided between the first electric motor (MG1, MG2) and drive wheels (44), wherein the power transmission device (30) is configured to selectively allow and prevent power transmission between the first electric motor (MG1, MG2) and the drive wheels (44); a control (60) configured to perform a warm-up control to increase the temperature of the lubricant, wherein the warm-up control to increase the temperature of the lubricant is performed when the power transmission device (30) is in a power-off state in which power transmission is prevented; characterized in that the first electric motor (MG1, MG2) is configured to be cooled by a lubricant of the power transmission device (30);a charging device (56) is provided which is configured to charge the power storage device (54) using a power supply located outside the electric vehicle; and the control (60) is configured to perform the warm-up control to increase the temperature of the lubricant if the temperature of the lubricant at the time of executing the charging of the power storage device (54) using the charging device (56) is lower than a predetermined temperature, and if the power transmission device (30) is in a neutral state in which the power transmission between the first electric motor (MG1, MG2) and the drive wheels (44) is blocked, the warm-up control being performed by rotating the first electric motor (MG1, MG2).

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The invention relates to an electric vehicle and a method for controlling it. In particular, the invention relates to an electric vehicle in which a power storage device, which stores power for driving the vehicle, can be charged with electrical power from a power supply located outside the vehicle, and to a method for controlling this type of vehicle. 2. Description of the state of the art

[0002] Japanese patent application 2009-89474 (JP 2009-89474 A) discloses an electric automobile having an onboard battery that can be charged by an external power supply. This type of electric automobile is equipped with a timer that allows the user to set the start and end times for charging the onboard battery using the external power supply. The timer makes it easy to check or confirm the charging schedule for the onboard battery and any prior pre-conditioning (air conditioning in the passenger compartment before boarding) (see JP 2009-89474 A). The prior art is also disclosed in Japanese patent application 2011-89625 A (JP 2011-896256 A) and Japanese patent application 2011-89625 A (JP 2011-896256 A).described in 2010-110196 (JP 2010-110196 A).

[0003] In an electric vehicle, such as a fully electric vehicle or a hybrid vehicle with an electric motor as a drive source, the viscosity of the lubricant increases if the temperature of the lubricant in the transmission, gearbox, etc., between the electric motor and the drive wheels decreases, resulting in increased rotational resistance. This reduces the efficiency of the power transmission to the drive wheels and shortens the electric vehicle's range. SUMMARY OF THE INVENTION

[0004] The invention provides an electric vehicle in which the temperature of the lubricant is sufficiently increased before the start of driving the vehicle, so that the range that the electric vehicle can travel can be extended as much as possible, and also provides a method for controlling the electric vehicle.

[0005] According to one aspect of the invention, an electric vehicle comprises a power storage device, a first electric motor, a power transmission device, a charging device, and a control unit. The power storage device is configured to store electrical power used to drive the vehicle. The first electric motor is configured to receive electrical power from the power storage device and to generate power. The power transmission device is provided between the first electric motor and the drive wheels, and the power transmission device is configured to selectively allow and suppress power transmission between the first electric motor and the drive wheels. The first electric motor is configured to be cooled by a lubricant in the power transmission device.The charging device is configured to charge the power storage device using a power supply located outside the vehicle. The controller is configured to perform a warm-up control to increase the lubricant temperature by rotating the first electric motor if the lubricant temperature is lower than a predetermined temperature at the time the power storage device used by the charging device is being charged, and if the power transfer device is in a power-cut-off state, in which power transfer is suppressed.

[0006] The electric vehicle may also have an electric oil pump configured to be electrically driven to circulate the lubricant. The control system may be configured to begin activating the electric oil pump before the warm-up process is executed.

[0007] In the electric vehicle described above, the control system can be configured to perform the warm-up control using electrical power supplied by the power supply when a quantity indicating the state of charge of the power storage device is greater than a predetermined value.

[0008] In the electric vehicle described above, the control system can be configured to perform the charging of the power storage device using the charging device, such that a quantity indicating the state of charge of the power storage device in a state prior to the execution of the warm-up control becomes greater than a predetermined value.

[0009] In the electric vehicle described above, the control unit can be configured to estimate an execution time of the warm-up control based on the temperature of the lubricant, and the control unit is configured to change an execution time at which the charging of the power storage device is performed using the charging device, based on the estimated execution time of the warm-up control.

[0010] The electric vehicle described above may also have a timer switch with which a user of the electric vehicle sets a time. The controller may be configured to estimate a planned operating start time based on the time set with the timer switch, the electric vehicle begins to be operated at the planned operating start time, and the controller is configured to execute the warm-up control before the estimated planned operating start time.

[0011] In the electric vehicle described above, the control system can be configured to execute the warm-up control before a scheduled end time at which the charging of the power storage device using the charging device ends.

[0012] The electric vehicle described above may also have a second electric motor and a power-sharing device. The second electric motor may be configured to be cooled by the coolant of the power-sharing device. The power-sharing device may have a first rotating element coupled to the first electric motor, a second rotating element coupled to the second electric motor, and a third rotating element. The control unit may be configured to rotate the second electric motor, as well as the first electric motor, during the warm-up phase.

[0013] The electric vehicle described above may also have a rotation suppression device. The rotation suppression device may be configured to suppress rotation of the third rotating element during the warm-up control. The control may be configured to rotate the first electric motor and the second electric motor such that the torque generated by the first electric motor and the torque generated by the second electric motor are balanced with respect to the third rotating element, which acts as a bearing, during the warm-up control. The power transmission device in the electric vehicle described above may also be a gearbox.

[0014] According to another aspect of the invention, a method for controlling an electric vehicle is provided. The electric vehicle has a power storage device, a first electric motor, a power transmission device, and a charging device. The power storage device is configured to store electrical power that is used to drive the vehicle. The first electric motor is configured to receive electrical power from the power storage device and to generate power. The power transmission device is provided between the first electric motor and the drive wheels, and the power transmission device is configured to selectively allow and suppress power transmission between the first electric motor and the drive wheels. The first electric motor is configured to be cooled by a lubricant in the power transmission device.The charging device is configured to charge the power storage device using a power supply located outside the vehicle.The control procedure has one step to determine whether the lubricant temperature is lower than a predetermined temperature at the time of executing the charging of the power storage device using the charging device, one step to determine whether the power transmission device is in a power-off state in which power transmission is suppressed, and one step to perform a warm-up control to increase the lubricant temperature by rotating the first electric motor if it is determined that the lubricant temperature is lower than the predetermined temperature at the time of executing the charging of the power storage device, and it is determined that the power transmission device is in the power-off state.

[0015] In the electric vehicle and its control method described above, the power transmission device is located between the first electric motor and the drive wheels. Warm-up is achieved by rotating the first electric motor when the power transmission device is in a power-off state during charging of the energy storage device using the charging device. This increases the lubricant temperature using heat generated by applying energy to the first electric motor, as well as the agitation of the lubricant caused by the motor's rotation.Thus, according to this invention, the temperature of the lubricant can be sufficiently increased before the vehicle starts driving, and the distance that the electric vehicle can travel can be extended as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Features, advantages and technical and industrial significance of exemplary embodiments of the invention are described below with reference to the attached drawings, in which the same reference numerals denote the same elements, and in which:

[0017] Fig. 1 is a view showing the general configuration of a hybrid vehicle from an example of an electric vehicle according to an embodiment of the invention;

[0018] Fig. 2. One view is that shows the main signals that are generated by a system in Fig. 1. Control is received and generated as shown;

[0019] Fig. 3 is a view that shows the structures of a differential unit and an automatic transmission. Fig. 1 shows;

[0020] Fig. 4 is a view that shows an intervention operating table of the automatic transmission. Fig. 3 shows;

[0021] Fig. 5 is a nomographic diagram of a shifting mechanism that is formed by the differential unit and the automatic transmission. Fig. 3 is determined;

[0022] Fig. 6 is a view that shows a shift diagram of the automatic transmission. Fig. 3 shows;

[0023] Fig. 7 is a view showing an example of a switching device used to select the switching position;

[0024] Fig. 8 is a flowchart that explains the processing procedure of the lubricant warm-up control, which is implemented by the in Fig. The control shown in section 1 is executed;

[0025] Fig. Figure 9 is a time graph showing changes in key parameters due to lubricant warm-up control, as described in Fig. The flowchart shown in section 8 is executed; and

[0026] Fig. 10 a nomographic diagram of the differential unit from Fig. 3 is. DETAILED DESCRIPTION OF EXECUTION FORMS

[0027] One embodiment of the invention is described in detail with reference to the drawings. In the drawings, the same or corresponding elements or sections are assigned the same reference numerals, the explanation of which will not be repeated.

[0028] Initially, the configuration of an electric vehicle is described. Fig. Figure 1 shows the general configuration of a hybrid vehicle. 10 as an example of the electric vehicle according to the embodiment of the invention. With reference to Fig. 1 has the hybrid vehicle 10a machine 12 , a differential unit 20 , an automatic transmission 30 , a differential gear device 42 and drive wheels 44 The hybrid vehicle 10 It also has a converter. 52 , a power storage device 54 , a battery charger 56 , an electrical power receiving unit 58 and a control system 60 . While the hybrid vehicle 10 If the vehicle is configured as an FR (front-mounted machine, rear-wheel drive) type, a different drive system may be used, for example.

[0029] The machine 12 is an internal combustion engine, such as a gasoline engine or a diesel engine. The engine 12It converts heat energy generated by the combustion of a fuel into kinetic energy of a moving body such as a piston or a rotor, and supplies the resulting kinetic energy to the differential unit. 20 Where the moving body is a piston, and its motion is a reciprocating motion, the reciprocating motion is converted into a rotary motion via a so-called crank mechanism, and the kinetic energy of the piston is converted into the differential unit. 20 transmitted.

[0030] The differential unit 20 is with the machine 12 coupled. The differential unit 20 has a converter 52 driven motor-generators and a power-sharing device that regulates the output or power of the machine 12 to a transmission element for transferring power to the automatic transmission 30and distributed to the motor-generators, as will be described later. The structure of the differential unit 20 will be described in detail later.

[0031] The automatic transmission 30 is with the differential unit 20 coupled, and can be actuated to change the ratio (speed ratio) between the speed of the transmission element (which is also known as an input shaft of the automatic transmission). 30 (serves), which is connected to the differential unit 20 is connected, and the rotational speed of a drive shaft (an output shaft of the automatic transmission) 30 ), which is connected to the differential gear unit 42 is connected, to change. When a specific clutch (which will be described later) is disengaged, the automatic transmission 30 able to form a neutral state in which the power transfer between the differential unit 20and the differential gear device 42 (drive wheels) 44 ) is locked or blocked.

[0032] In this embodiment, the automatic transmission 30 A step-variable transmission that has two or more gear ratio positions and is capable of changing the gear ratio in steps. However, the automatic transmission can 30 It will be a continuously variable transmission (CVT). The differential gear device 42 is connected to the output shaft of the automatic transmission 30 coupled and transmits power from the automatic transmission 30 to the drive wheels 44 The structure of the automatic transmission 30 as well as those of the differential unit 20 will be described in detail later.

[0033] The converter 52 is electrically connected to the power storage device 54connected and drives the differential unit 20 existing motor-generators starting from a control signal from the controller 60 on. The converter 52 This is provided, for example, by a bridge circuit with power semiconductor switching elements for three phases. Although not specifically shown in the drawings, a voltage converter can be used between the converter. 52 and the power storage device 54 be provided.

[0034] The power storage device 54 A rechargeable DC power supply is typically an auxiliary battery such as a lithium-ion battery or a nickel-metal hydride battery. The power storage device 54 It stores electrical power to drive the vehicle and transfers the stored power to the converter. 52 to. The power storage device 54is supplied by the power receiving unit 58 The power receiving unit is charged with received electrical power. 58 receives electrical power from a power supply (not shown) located outside the vehicle (called the "external power supply"), and charges the power storage device. 54 (using the external power supply, which is referred to as "external charging"). The power storage device 54 is also powered by the motor-generator of the differential unit 20 and from the converter 52 The received electrical power is charged. The power storage device 54 can consist of a power storage element such as an electrical double-layer capacitor instead of the auxiliary battery.

[0035] The battery charger 56 is electrically connected to a range between the power storage device 54and the power receiving unit 58 connected and can be activated to receive power from the power receiving unit 58 to convert the electrical power received during external charging into a power that provides a voltage level for the power storage device 54 features, and the power storage device 54 Charging with power. The power receiving unit 58 It may have a connector, plug or similar device that is electrically connected to the external power supply, or it may be a winding, antenna or similar device that receives electrical power from the external power supply without contact.

[0036] The control 60 has a machine ECU (electronic control unit) 62 , an MG ECU 64 , a battery ECU 66 , a charging ECU 68 and HV-ECU 70Each of these ECUs has a CPU (central processing unit), a memory device, input and output buffers, etc. (none of which are shown), and performs various control operations, as will be described later. The control operations performed by each ECU are not limited to processing using software but can be implemented by dedicated hardware (electronic circuits). While the ECUs, as shown above, control 60 determine the control 60 consist of a single ECU.

[0037] The machine ECU 62 generates signals, such as a throttle signal, an ignition signal and a fuel injection signal, to operate the machine 12 to drive based on a machine moment instruction, etc., which is provided by the HV-ECU 70 was received, and sends the generated signals to the machine. 12 off. The MG-ECU64 generates a control signal to control the converter 52 based on an instruction from the HV-ECU 70 , and sends the generated control signal to the converter. 52 out of.

[0038] The battery ECU 66 estimates the state of charge (also called "SOC") of the power storage device 54 starting from the voltage and current of the power storage device 54 , which are detected by a voltage sensor or a current sensor (not shown), and outputs the estimated result to the HV-ECU. 70 The state of charge (SOC) is expressed as a percentage between 0% and 100%, where 100% represents a fully charged state. The charging ECU 68 generates a control signal to control the battery charger. 56 based on an instruction from the HV-ECU 70 and sends the generated control signal to the battery charger. 56 out of.

[0039] The HV-ECU 70It receives detection signals from various sensors and generates various instructions to control corresponding devices of the hybrid vehicle. 10 As one of the main controls, which are managed by the HV-ECU 70 The HV-ECU performs the following tasks: 70 a warm-up control to increase the temperature of the lubricant, which is jointly supplied by the differential unit 20 and the automatic transmission 30 is used. If the lubricant temperature is low at the time of external charging, and the automatic transmission is in neutral (power cut-off state), the HV-ECU generates 70 More precisely, instructions for powering the battery charger. 56 and gives the instruction to the charging ECU 68 off, and the HV-ECU 70 It also generates current instructions to control the differential unit. 20to rotate existing engine-generators, and gives the instruction to the MG-ECU. 64 The warm-up control will be described in detail later.

[0040] Fig. Figure 2 shows main signals that lead to the Fig. 1 visible control 60 sent and received from there. With reference to Fig. 2 receives the HV-ECU 70 a signal from a vehicle speed sensor that measures the speed of the hybrid vehicle 10 detected, a signal from an accelerator pedal position sensor, which detects the operating parameter of the accelerator pedal, a signal from a machine speed sensor, which detects the speed of the machine 12 detected, a signal from an MG1 speed sensor, which detects the speed of a motor-generator MG1 (which will be described later) located in the differential unit 20is present, and a signal from an MG2 speed sensor, which detects the speed of a motor-generator MG2 (which will be described) located in the differential unit 20 is present. The HV-ECU 70 It also receives a signal from an output shaft speed sensor, which measures the speed of an output shaft of the differential unit. 20 captured (which also includes the input shaft of the automatic transmission) 30 is), a signal from a machine crank angle sensor, which measures the crank angle of the machine 12 A signal was captured from a machine coolant temperature sensor, which measures the temperature of the machine's coolant. 12 A signal from an inlet air temperature sensor, which measures the temperature of the air entering the machine, is detected. 12 drawn air is detected, and a signal from a lubricant temperature sensor, which measures the temperature of the lubricant in the differential unit, is received. 20 and the automatic transmission30 recorded. Additionally, the HV-ECU receives 70 in addition, a signal from an outside air temperature sensor, which measures the temperature of the outside air around the hybrid vehicle 10 around, a signal from a shift position sensor that detects a shift position designated by a shift lever, a signal from a timer switch with which the user is able to set the time at which the external charging is scheduled to be completed, the time at which the hybrid vehicle 10 is planned to start, which is activated after external charging, etc., a signal that is for the SOC of the power storage device. 54 The indicator is the one controlled by the battery ECU. 66 is estimated, etc.

[0041] Then the HV-ECU generates 70 a machine moment instruction Ter, which relates to a target output torque of the machine 12Indicating, e.g. based on the signals shown above, and gives the instruction Ter to the machine ECU 62 off. The machine's ECU 62 , which receives the machine moment instruction Ter, generates a throttle signal, an ignition signal, a fuel injection signal, etc., to control the machine 12 to drive, and sends these signals to the machine 12 out of.

[0042] The HV-ECU 70 It also generates current instructions Img1, Img2 to power the motor-generators MG1, MG2 of the differential unit. 20 to power it, and gives instructions to the MG-ECU. 64 off. The HV-ECU 70 Pac also generates a charging instruction to the battery charger. 56 to drive, and gives the instruction Pac to the charging ECU. 68 off, and the HV-ECU 70 It also generates a hydraulic signal to drive the automatic transmission. 30, and outputs the hydraulic signal to a hydraulic control unit (not shown). The HV-ECU also generates 70 a signal as an instruction to drive an electric oil pump (not shown) to circulate the lubricant, and outputs the signal to the electric oil pump.

[0043] The MG ECU 64 , which send the current instructions Img1, Img2 from the HV-ECU 70 Upon receiving the signal, a PWI signal is generated to control the converter. 52 so that currents flow through the motor generators MG1 and MG2 according to the current instructions Img1, Img2, and outputs the resulting signal PWI to the converter. 52 Off. The charging ECU 68 , which sends the Pac power instruction from the HV-ECU 70 It receives a signal, PWC, which is used to control the battery charger. 56 so that the power storage device 54The battery is charged with electrical power according to the charging instruction Pac, and sends the resulting signal PWC to the battery charger. 56 out of.

[0044] Next, the structures of the differential unit and the automatic transmission will be described. Fig. Figure 3 shows the structures of the differential unit 20 and the automatic transmission 30 , that from Fig. 1 is evident. The differential unit 20 and the automatic transmission 30 are constructed symmetrically with respect to their axis; therefore, the lower halves of the differential unit are 20 and the automatic transmission 30 in Fig. 3 not shown.

[0045] With reference to Fig. 3 has differential unit 20 Motor-generators MG1, MG2 and a power distribution device 24Each of the motor-generators MG1 and MG2 is a rotating DC electric machine, such as a permanent magnet synchronous motor with a rotor in which a permanent magnet is embedded. The motor-generators MG1 and MG2 are driven by the converter. 52 powered ( Fig. 1) The motor-generators MG1, MG2 are lubricated using the lubricant of the automatic transmission. 30 and the power distribution device 24 cooled. On the other hand, the motor-generators MG1 and MG2 are cooled by the converter. 52 driven when the temperature of the lubricant is low, in order to raise the temperature of the lubricant by using heat generated by applying energy to the motor-generators and stirring the lubricant due to the rotation of the motor-generators.

[0046] The power distribution device 24It is a planetary gear set of the type with individual planets and has a sun gear S0, a pinion P0, a carrier CA0 and a ring gear R0. The carrier CA0 is connected to an input shaft. 22 coupled, namely with the output shaft of the machine 12 , and supports the planet P0 in such a way that the planet P0 is able to rotate around itself and around the sun gear S0. The sun gear S0 is coupled to the rotating shaft of the motor-generator MG1. The ring gear R0 is connected to the transmission element. 26 coupled and arranged to mesh with the sun gear S0 over the planet P0. The rotating shaft of the motor-generator MG2 is connected to the transmission element. 26 coupled. The ring gear R0 is also coupled to the rotating shaft of the motor-generator MG2.

[0047] The power distribution device 24It functions as a differential device in which the sun gear S0, the carrier CA0, and the ring gear R0 rotate relative to each other. The corresponding rotational speeds of the sun gear S0, the carrier CA0, and the ring gear R0 are related to being connected by a straight line, as shown in the nomographic diagram ( Fig. 5) is indicated, which will be described later. Due to the differential function of the power distribution device 24 will be done by the machine 12 The generated power is distributed to the sun gear S0 and the ring gear R0. Then, the motor-generator MG1 operates as a generator using the power supplied to the sun gear S0, and the electrical power generated by the motor-generator MG1 is fed to the motor-generator MG2 or stored in the power storage device. 54 saved (see Fig. 1) The motor-generator MG1 generates electrical power using power supplied by the power-sharing device. 24 was subdivided, and the motor-generator MG2 is driven using the electrical power generated by the motor-generator MG1, so that the differential unit 20 functions as a continuously variable transmission (CVT).

[0048] A freewheel F2 is attached to the input shaft connected to the carrier CA0 22 provided. The freewheel F2 supports the input shaft. 22 such that the input wave 22 in a positive direction of rotation (the direction of rotation of the input shaft) 22 during the operation of the machine 12 ) can rotate, and cannot rotate in a negative direction.

[0049] The automatic transmission 30 has planetary gear sets 32 , 34of the type with individual planets, clutches C1–C3, brakes B1, B2 and a freewheel F1. The planetary gear set 32 The planetary gear set has a sun gear S1, a planet P1, a carrier CA1 and a ring gear R1. 34 has a sun gear S2, a planet P2, a carrier CA2 and a ring gear R2.

[0050] Each of the clutches C1–C3 and the brakes B1, B2 is a friction clutch device operating under hydraulic pressure and can be a wet disc friction clutch having a plurality of friction plates stacked on top of each other, adapted to be pressed under hydraulic pressure, or a band brake in which one end of a band wound around an outer circumferential surface of a rotating drum is adapted to be pulled under hydraulic pressure to tighten the band, or similar. The freewheel F1 supports the carrier CA1 and the ring gear R2, which are coupled to each other, such that the carrier CA1 and the ring gear R2 can rotate in one direction and cannot rotate in the other.

[0051] In the automatic transmission 30 The coupling devices, i.e., the clutches C1–C3, the brakes B1, B2 and the freewheel F1, are according to a Fig. 4. The intervention operating table shown is engaged, so that a selected position from the first speed reduction position to the fourth speed reduction position and the reverse reduction position is established. In Fig. 4 denotes "O" that the clutch device in question is in an engaged state, and "(O)" denotes that a machine brake is applied when the clutch device is engaged, while "∆" indicates that the clutch device is engaged only while driving, and a blank indicates that the clutch device is in a disengaged state. The automatic transmission 30 can be placed in a neutral state (in which the power transmission is shut off) by disengaging all coupling devices, i.e. the clutches C1–C3 and the brakes B1, B2.

[0052] Again with reference to Fig. 3. The differential unit 20 and the automatic transmission30 together through the transmission element 26 coupled. The one with the carrier CA2 of the planetary gear set 34 coupled output shaft 36 is with the differential gear device 42 coupled ( Fig. 1).

[0053] Fig. Figure 5 is a nomographic diagram of a speed change mechanism implemented by the differential unit. 20 and the automatic transmission 30 is determined. With reference to Fig. 3 together with Fig. Figure 5 shows a vertical line Y1 in the nomographic diagram corresponding to the differential unit. 20 the rotational speed of the sun gear S0 of the power distribution device 24 , namely the rotational speed of the motor-generator MG1. A vertical line Y2 shows the rotational speed of the carrier CA0 of the power distribution unit. 24 , namely the rotational speed of the machine 12A vertical line Y3 indicates the rotational speed of the ring gear R0 of the power distribution device. 24 , namely the rotational speed of the motor-generator MG2. The distances between the vertical lines Y1 to Y3 are determined according to the gear ratio of the power distribution device. 24 certainly.

[0054] In the nomographic diagram, according to the automatic transmission 30 A vertical line Y4 shows the rotational speed of the sun gear S2 of the planetary gear set. 34 and a vertical line Y5 shows the rotational speed of the carrier CA2 of the planetary gear set 34 of the ring gear R1 of the planetary gear set 32 which are coupled together. A vertical line Y6 shows the rotational speed of the ring gear R2 of the planetary gear set. 34 and the carrier CA1 of the planetary gear set 32on, which are coupled together, and a vertical line Y7 shows the rotational speed of the sun gear S1 of the planetary gear set 32 The distances between the vertical lines Y4 to Y7 are determined according to the gear ratios of the planetary gear sets. 32 , 34 certainly.

[0055] When clutch C1 is engaged, the sun gear S2 of the planetary gear set 34 with the ring gear R0 of the differential unit 20 The gears are coupled so that the sun gear S2 rotates at the same speed as the ring gear R0. When the clutch C2 is engaged, the carrier CA1 of the planetary gear set is... 32 and the ring gear R2 of the planetary gear set 34 The ring gear R0 is coupled in such a way that the carrier CA1 and the ring gear R2 rotate at the same speed as the ring gear R0. When the clutch C3 is engaged, the sun gear S1 of the planetary gear set 32The ring gear R0 is coupled such that the sun gear S1 rotates at the same speed as the ring gear R0. The rotation of the sun gear S1 stops when the brake B1 is engaged, and the rotation of the carrier CA1 and the ring gear R2 stops when the brake B2 is engaged.

[0056] For example, if clutch C1 and brake B1 are engaged, and the remaining clutches and brakes are released, as shown in the engagement operating table of the Fig. The number 4 shown is a straight line labeled "2." in the nomographic diagram of the automatic transmission. 30 selected. The vertical line Y5, which represents the rotational speed of the carrier CA2 of the planetary gear set. 34 The display shows the output speed (the speed of the output shaft). 36 ) of the automatic transmission 30 on. Thus, in the automatic transmission 30the clutches C1–C3 and the brakes B1, B2 selected according to the engagement operating table of the Fig. 4 so engaged and released that the first speed transmission position up to the fourth speed transmission position, reverse transmission position and the neutral state can be formed.

[0057] In the differential unit 20 On the other hand, the rotations of the motor-generators MG1, MG2 are appropriately controlled so that the rotational speed of the ring gear R0, namely the rotational speed of the transmission element, is 26 continuously relative to a given rotational speed of the machine 12 , which is coupled to the carrier CA0, can be varied to ensure that the speed ratio is steplessly or continuously variable. By coupling the automatic transmission 30 , which is able to determine the speed ratio between the transmission element 26 and the output shaft 36to change, with the differential unit 30 , which has a continuously variable speed change function, it is possible to determine the speed ratio to the differential unit 20 to reduce, while the stepless speed change function of the differential unit 20 to ensure that losses of the motor-generators MG1, MG2 are reduced.

[0058] Fig. 5 shows an operating state of the differential unit 20 As an example, consider a situation where the rotational speed of motor-generator MG1 (the rotational speed of the sun gear S0) is zero. This operating state is called the "mechanical point," at which no electrical power flows into motor-generator MG1, and the machine's power output is zero. 12The power is transmitted without being converted into electrical energy. At the "mechanical point," neither "power distribution" nor "power circulation" takes place, and the power transmission efficiency is high. In the "power distribution" stage, the motor-generator MG1, which supplies power to the machine, is used to transfer the power. 12 The electrical power generated is used and fed to the motor-generator MG2, thus generating the driving force. In the "power cycle," electrical power generated by motor-generator MG2 flows into motor-generator MG1. In the hybrid vehicle 10 In this embodiment, two or more "mechanical points" can be located in the differential unit. 20 according to the translation position of the automatic transmission 30 be trained so that a high power transmission efficiency can be achieved under various driving conditions.

[0059] Since the automatic transmission 30The motor-generators MG1 and MG2 of the differential unit can be placed in the neutral state, as described above. 20 to be rotated in a state where power to the drive wheels is suppressed. 44 is transferred. If, in this embodiment, the lubricant temperature is low at the time of external charging, and the automatic transmission 30 When the vehicle is in the neutral state, the warm-up control for increasing the lubricant temperature is carried out by rotating the motor-generators MG1 and MG2. This is because the automatic transmission... 30 When the system is in a state of power being cut off, the warm-up control is carried out using the motor-generators MG1 and MG2, without supplying drive power to the drive wheels. 44 to deliver.

[0060] Gear shifting via the differential unit 20and the automatic transmission described above 30 is controlled based on a circuit diagram, as e.g. in Fig. 6 is displayed. With reference to Fig. Figure 6 shows the vehicle speed on the horizontal axis and the output torque of the hybrid vehicle on the vertical axis. 10 This is calculated based on the accelerator pedal input, vehicle speed, etc. It should be understood that parameters determining the change in rotational speed are not limited to these parameters.

[0061] In Fig. 6. Solid lines are upshift lines, and dashed lines are downshift lines. An area enclosed by a dash-dot line represents an engine driving range (EV driving range) in which the machine 12 The vehicle is stopped and is only powered by the MG2 motor-generator. During EV driving, the machine... 12stopped unless a request is received to charge the power storage device 54 due to a reduction in SOC or a requirement to warm up a catalyst (not shown) or similar. In an area outside the area enclosed by the dash-dot line, the machine is 12 activated, so that the vehicle can be operated using only the power supplied by the machine 12 generated drive power, or the vehicle operates in an HV operating mode that uses the drive power of the motor-generator MG2 in addition to that generated by the machine 12 The generated drive power is used. Shifting is also performed while the vehicle is driving in EV mode.

[0062] Fig. Figure 7 shows an example of a switching device used for switching or changing the switching position. With reference to Fig. 7 is the switching device 46e.g. installed next to the driver's seat and with a gearshift lever 48 provided, which is operated to select one of a plurality of switching positions.

[0063] The gearshift lever 48 can be manually moved to a park position "P (Park)", a reverse position "R (Reverse)", a neutral position "N (Neutral)", an automatic forward shift position "D (Drive)", or a manual forward shift position "M (Manual)". If the shift lever 48 When in the "P" position, a neutral state is established in which the power transmission path in the automatic transmission 30 is locked or blocked, and the output shaft of the automatic transmission 30 is locked. If the gearshift lever 48 When the gearshift lever is in the "R" position, the reverse driving position is selected for driving the vehicle backwards.48 When in the "N" position, a neutral state is established in which the power transmission path in the automatic transmission 30 is locked or blocked. The "N" position and the previously displayed "P" position are not driving positions (non-driving positions) in which the automatic transmission is engaged. 30 is placed in a state of power being cut off. When the gearshift lever 48 When in the "D" position, automatic shift control is performed within a range where the speed ratio or gear ratio is determined by the differential unit. 20 and the automatic transmission 30 can be changed. If the gearshift lever 48When in the "M" position, a manual shift mode is established, and a so-called shift range is set, while a high-speed shift position (shift positions) is limited, which are established under the automatic shift control.

[0064] Next, the warm-up control system will be described. In the hybrid vehicle 10 The lubricant is used together in the differential unit. 20 and the automatic transmission 30 used or divided by them. If the lubricant temperature is reduced, the lubricant viscosity increases, which affects the differential unit. 20 and the automatic transmission 30 The rotational resistance increases. As a result, the power transmission efficiency of the differential unit is reduced. 20 and the automatic transmission 30 reduced, and the distance that the hybrid vehicle10 The distance for driving is shortened.

[0065] In this embodiment, if the lubricant temperature is low, the warm-up control to increase the lubricant temperature is carried out using the motor-generators MG1 and MG2. More precisely, the automatic transmission 30 When in a neutral state (when the "N" position or the "P" position is selected), electric current flows through the motor generators MG1, MG2 of the differential unit. 20 The fluid is routed through to rotate the motor-generators MG1 and MG2. In this way, the lubricant is heated by the agitation caused by the energy applied to the motor-generators MG1 and MG2 and by their rotation. The power generated by the rotation of the motor-generators MG1 and MG2 is transmitted through the automatic transmission. 30 blocked. If the automatic transmission 30if the transmission is not in neutral when the warm-up control is executed, the automatic transmission may 30 positively controlled so that it is placed in the neutral state.

[0066] The power transmission efficiency is improved if the lubricant temperature is increased by the warm-up control using the motor-generators MG1, MG2; however, if electrical power is drawn from the power storage device 54 During the warm-up control, the distance traveled by the hybrid vehicle is taken into account. 10 The operating time is ultimately shortened. Thus, in this embodiment, the warm-up control is executed during external charging. Specifically, if the lubricant temperature is low during external charging, the battery charger 56 activated, and the motor-generators MG1, MG2 are rotated if the automatic transmission30 is in the neutral state ("N" position or "P" position). Thus, the motor-generators MG1 and MG2 can be driven during the warm-up control using electrical power supplied from the external power supply, and the warm-up control can be implemented without drawing electrical power from the power storage device. 54 to be taken.

[0067] Fig. Figure 8 is a flowchart that explains the processing procedure of the control system for increasing the temperature of the lubricant, which is controlled by the controller. 60 out of Fig. 1 is executed. Each step in the flowchart is implemented if a step is pre-defined in the control. 60A stored program is called by a main routine and executed at given intervals or when a given condition (or conditions) is / are met. For all or some of the steps in the flowchart, the processing can be implemented by constructing dedicated hardware (electronic circuitry).

[0068] With reference to Fig. 8 determines the control 60 , whether the power storage device 54 externally using the battery charger 58 is being loaded (step S10). If the power storage device 54 If the external load is not used, the controller proceeds to step S120 without performing a series of actions described below.

[0069] If step S10 determines that the power storage device 54 The controller determines whether an external load is used (YES in step S10) (YES in step S10). 60, whether the currently selected shift position is the "N" position or the "P" position, namely whether the automatic transmission 30 is in the neutral state (power cut-off state) (step S20). If the currently selected switching position is a position other than the "N" position and the "P" position (NO in step S20), the control system proceeds to step S120.

[0070] If step S20 determines that the switching position is the "N" position or the "P" position (YES in step S20), the controller determines 60 , whether the SOC of the power storage device 54 is higher than a predetermined threshold (step S30). The threshold is a value used to determine whether the power storage device 54The system is sufficiently charged. If the SOC is equal to or lower than the threshold (NO in step S30), the control progresses to step S120.

[0071] In this embodiment, a high state of charge (SOC) is a prerequisite for the execution of the warm-up control to increase the lubricant temperature. As described above, the warm-up control is executed during external charging, and electrical power supplied by the external power supply is used for the warm-up control. Therefore, it is desirable for the external power supply to have sufficient power capability to charge the power storage device. 50and to supply electrical power to the motor-generators MG1 and MG2 for warm-up control at the same time. However, the external power supply cannot only have such a power supply capability. Thus, in this embodiment, the amount of charge in the power storage device 54 , which predominantly determines the distance the vehicle can travel in EV mode, is preferably made sufficiently large, and the warm-up control can be executed under a condition that the SOC of the power storage device 54 is sufficiently high. In other words, the charging of the power storage device 54 is implemented in such a way that the SOC of the power storage device 54 is sufficiently increased before the warm-up control is executed.

[0072] While the SOC is used as a set of states that describe the state of charge of the power storage device 54The SOC can be indicated by a different amount of a state (such as a voltage of the power storage device). 54 ) are replaced, which are responsible for the state of charge of the power storage device 54 indicating, and it can be determined whether the power storage device 54 is sufficiently charged by comparing the amount of the state to a given threshold.

[0073] If step S30 determines that the SOC is higher than the threshold (YES in step S30), the controller calculates 60 the execution time of the warm-up control (step S40). As an example, the control calculates 60a duration or length of time required to raise the temperature of the lubricant to a target temperature, sufficiently different from the temperature of the lubricant as detected by the lubricant temperature sensor, the temperature of the outside air as detected by the outside air temperature sensor, etc.

[0074] Then the controller calculates 60 The intended start time of operation, at which the hybrid vehicle is intended to begin operating (step S50). The intended start time is calculated so that the warm-up control and external charging end before the planned time at which the hybrid vehicle 10 begins to be activated. The intended start time can be set directly with a timer switch ( Fig. 2) can be set, which can be operated by the user, or can be calculated from a predetermined time (e.g. in the morning) at which the external loading should be completed.

[0075] Consequently, the control determines 60 The controller determines whether the warm-up control execution time has elapsed, based on the intended start-up time calculated in step S50 and the warm-up control execution time calculated in step S40 (step S60). The controller calculates this even more precisely. 60The execution time of the warm-up control is calculated by subtracting the warm-up duration calculated in step S40, plus a suitable extra period, from the intended start-up time calculated in step S50. This determines whether the intended warm-up execution time has been reached. If the time for warm-up execution has not been reached (NO in step S60), the control system proceeds to step S120.

[0076] If step S60 determines that the time for executing the warm-up control has arrived (YES in step S60), the controller determines 60 The controller checks whether the lubricant temperature, as detected by the lubricant temperature sensor, is lower than a predetermined threshold (step S70). If it is determined that the lubricant temperature is lower than the threshold (YES in step S70), the controller calculates...60 Values ​​of the current flowing through motor-generators MG1 and MG2, and the rotational speeds of motor-generators MG1 and MG2 required to increase the lubricant temperature (step S80). The current values ​​and rotational speeds can be determined from characteristic maps or calculation formulas, etc., prepared in advance according to the lubricant temperature detected by the lubricant temperature sensor, or they can be determined by ensuring a high current flows through the motor-generator, which is more likely to immerse itself in the lubricant, based on the vehicle body's inclination, detected, for example, by an inclination sensor (not shown).

[0077] If step S70 determines that the lubricant temperature is equal to or higher than the threshold (NO in step S70), the controller calculates 60Values ​​of the current flowing through motor-generators MG1 and MG2, and the rotational speeds of motor-generators MG1 and MG2 required to maintain the lubricant temperature (step S90). The current values ​​and rotational speeds for maintaining the lubricant temperature are smaller or lower than the current values ​​and rotational speeds for increasing the temperature calculated in step S80.

[0078] Then the control system activates 60 The electric oil pump circulates the lubricant (step S100). External charging is performed after driving the vehicle (e.g., late at night after arriving home), and the lubricant is back in an oil pan at the time of external charging. Therefore, the electric oil pump is activated before the warm-up control is executed to prevent the clutches (on clutches C1–C3) and shafts of the automatic transmission from overheating. 30The rotation of the motor-generators MG1 and MG2 is caused to burn out under the warm-up control. After the electric oil pump is activated, the control unit takes over. 60 the converter 52 so that the motor-generators MG1, MG2 operate according to the current values ​​and speeds calculated in step S80 or step S90 in order to carry out the warm-up control (step S110).

[0079] While the start time of the warm-up control is determined based on the execution time of the warm-up control, which was calculated in step S40 of the control routine as described above, the warm-up control is executed under the condition that the SOC of the power storage device 54 is higher than the threshold. Thus, the time required to execute the external charge (the time at which the power storage device is charged) can be increased. 54(starts) can be determined, or the electrical charging power for the use of external charging can be increased (fast charging can be performed), based on the execution time of the warm-up control, so that the SOC of the power storage device 54 The threshold value is reached at the start of the warm-up control.

[0080] In the control routine described above, the lubricant warm-up control can be executed under the condition that the currently selected switching position is the "N" position or the "P" position. However, if the switching position selected at the time of execution of the warm-up control is any position other than the "N" position or the "P" position, the switching position can be changed to a position positive for the "N" position or the "P" position.

[0081] Fig. Figure 9 is a time graph showing changes in key parameters that occur with lubricant warm-up control. With reference to Fig. 9, if external charging (charging the power storage device) 54 ) is performed using the external power supply, and the SOC of the power storage device 54If a predetermined threshold is exceeded at time t1, the conditions for executing the warm-up control are met. Then, at time t2, the motor-generators MG1 and MG2 are driven in opposite directions of rotation. As a result, the lubricant is warmed up (i.e., its temperature increases) due to the heat generated by the energy supplied to the motor-generators MG1 and MG2 and the agitation of the lubricant caused by their rotation. Since electrical power can be supplied from the external power supply during the warm-up control, electrical power for use in the warm-up control is supplied from the external power supply to the motor-generators MG1 and MG2, to the state of charge (SOC) of the power storage device. 54 is not reduced.

[0082] If the lubricant temperature reaches a predetermined temperature at time t3, a current is passed through the motor-generators MG1 and MG2 to maintain the temperature. During the rotations of the motor-generators MG1 and MG2 in the example of the Fig. When the system is stopped at time 9, the motor-generators MG1 and MG2 can be rotated while the lubricant temperature is maintained at the elevated level. Then, the end time of the external charging occurs at time t4, and both the lubricant warm-up control and the external charging end before the intended start-up time, which is designated by time t5.

[0083] The heat generated by the motor-generators MG1, MG2 increases when the current flowing through the motor-generators MG1, MG2 is higher, so that the lubricant temperature can rise rapidly. In this embodiment, the freewheel F2 (see Fig. 3) at the input shaft 22(the output shaft of the machine 12 ) provided, which is connected to the carrier CA0 of the power distribution device 24 the differential unit 20 is coupled. As can be seen from the nomographic diagram of the Fig. As can be seen in Figure 10, the motor-generators MG1 and MG2 are driven in such a way that the torque T1 of motor-generator MG1 and the torque T2 of motor-generator MG2 cancel each other out with the freewheel F2 as a reference point, so that a large torque can be generated at the motor-generators MG1 and MG2. This allows a high current to flow through the motor-generators MG1 and MG2, and the temperature of the lubricant can be increased rapidly.

[0084] As described above, in this embodiment the warm-up control is implemented to increase the lubricant temperature during the external charging of the external power supply; therefore, electrical power for use in the warm-up control is not drawn from the power storage device. 54 removed. In addition, the automatic transmission 30 between the differential unit 20 and the drive wheels 44 provided, and the warm-up control is carried out by rotating the motor-generators MG1, MG2, while the automatic transmission 30is in the neutral state (power cut-off state); therefore, the lubricant temperature is increased due to the heat generated by supplying energy to the motor-generators MG1 and MG2, and the lubricant temperature is also increased due to the agitation of the lubricant caused by the rotation of the motor-generators MG1 and MG2. Thus, according to this embodiment, the lubricant temperature is sufficiently increased before the vehicle starts driving, and the distance the hybrid vehicle travels 10 Driving can be extended as far as possible.

[0085] According to this embodiment, the electric oil pump is activated before the warm-up control is executed; therefore, the clutches and shafts of the automatic transmission are prevented from overheating. 30 due to the rotation of the motor-generators MG1, MG2 under the warm-up control.

[0086] According to this embodiment, the warm-up control is executed when the SOC of the power storage device 54 The state of charge (SOC) is higher than the predetermined threshold; in other words, external charging is executed in such a way that the SOC exceeds the threshold before the warm-up control is triggered. Therefore, the warm-up control degrades the charging of the power storage device. 54 not, which predominantly determines the distance the vehicle can travel in EV driving mode.

[0087] In this embodiment, the execution time of the warm-up control is calculated based on the lubricant temperature detected by the lubricant temperature sensor, the ambient air temperature detected by the ambient air temperature sensor, and so on. Then, the execution time of the external charging (the time until the charging of the power storage device) is calculated. 54is started) determined, or the charging power for external charging is increased (fast charging is performed), based on the execution time of the warm-up control, so that the warm-up control can be achieved with high reliability, while a sufficient charge amount of the power storage device 54 is ensured.

[0088] In the illustrated embodiment, the electric vehicle is in the form of a hybrid vehicle, to which the machine is attached. 12 is installed. However, the scope of application of the invention is not limited to the hybrid vehicle described above, but can include an electric car in which no machine is installed, a fuel cell car in which a fuel cell is further installed as an energy source, etc.

[0089] While the hybrid vehicle 10 the automatic transmission 30 has, and the automatic transmission30 is arranged to suppress power to the drive wheels 44 During the execution of the warm-up control, another power transmission device may be provided in the illustrated embodiment, which is capable of selectively transferring power between the differential unit. 20 and the drive wheels 44 instead of the automatic transmission 30 to allow and suppress. For example, only a clutch may be provided instead of the automatic transmission, and the warm-up control may be executed when the clutch is disengaged, or the clutch may be controlled, for example, to be placed in a disengaged state as a result of the execution of the warm-up control.

[0090] In the illustrated embodiment, one of the motor-generators MG1, MG2 corresponds to one example of the "first electric motor" according to the invention, and the other of the motor-generators MG1, MG2 corresponds to one example of the "second electric motor" according to the invention. The automatic transmission 30 corresponds to one example of the "power transmission device" according to the invention, and the battery charger 56 and the power receiving unit 58 form an example of the "charging device" according to the invention. The differential unit 20 corresponds to one example of the "differential device" according to the invention, and the freewheel F2 corresponds to one example of the "rotation suppression device" according to the invention.

[0091] It is to be understood that the embodiments disclosed herein are in every respect exemplary and not limiting. The scope of this invention is not defined by the description of the embodiments shown but by the appended claims, and it is intended to include all changes or modifications made within the scope of the claims and their equivalents.

Claims

[1] Electric vehicle with: a power storage device configured to store electrical power used to drive the vehicle; a first electric motor configured to receive electrical power from the power storage device, wherein the first electric motor generates power; a power transmission device provided between the first electric motor and the drive wheels, wherein the power transmission device is configured to selectively permit and prevent power transmission between the first electric motor and the drive wheels, wherein the first electric motor is configured to be cooled by a lubricant of the power transmission device; a charging device configured to charge the power storage device using a power supply located outside the vehicle; and a controller configured to perform a warm-up control to increase the temperature of the lubricant by rotating the first electric motor when the temperature of the lubricant is lower than a predetermined temperature at the time of executing the charging of the power storage device using the charging device, and when the power transmission device is in a state of power shut-off by preventing power transmission. [2] Electric vehicle according to claim 1, further comprising: an electric oil pump configured to be electrically driven to circulate the lubricant, wherein The control system is configured to start activating the electric oil pump before the warm-up control is executed. [3] Electric vehicle according to claim 1, wherein the control is configured to perform the warm-up control using electrical power supplied from the power supply when a quantity of a state indicating the state of charge of the line storage device is greater than a predetermined value. [4] Electric vehicle according to claim 1, wherein the control is configured to perform charging of the power storage device using the charging device such that a magnitude of a state indicating the state of charge of the power storage device becomes greater than a predetermined value before the warm-up control is executed. [5] Electric vehicle according to claim 4, wherein the controller is configured to estimate an execution time of the warm-up control based on the temperature of the lubricant, wherein the controller is configured to change an execution time at which a charging of the power storage device is performed using the charging device based on the estimated execution time of the warm-up control. [6] Electric vehicle according to claim 1, further comprising: a timer switch with which a user of the electric vehicle sets a time, whereby The controller is configured to estimate a planned start time from the time set by the timer, where the planned start time is a time at which the electric vehicle will begin operating, and the controller is configured to execute the warm-up control before the estimated planned start time. [7] Electric vehicle according to claim 1, wherein the control is configured to execute the warm-up control prior to a planned end time at which the charging of the power storage device using the charging device ends. [8] Electric vehicle according to claim 1, further comprising: a second electric motor configured to be cooled by the coolant of the power transmission device; and a power sharing device comprising a first rotating element coupled to the first electric motor, a second rotating element coupled to the second electric motor, and a third rotating element, wherein The control system is configured to rotate both the second electric motor and the first electric motor during the execution of the warm-up control. [9] Electric vehicle according to claim 8, further comprising: a rotation-suppressing device configured to suppress rotation of the third rotating element during the execution of the warm-up control, wherein The control is configured to rotate the first electric motor and the second electric motor such that a torque generated by the first electric motor and a torque generated by the second electric motor are balanced with respect to the third rotating element as the bearing point during the execution of the warm-up control. [10] Electric vehicle according to claim 1, wherein the power transmission device comprises a gearbox. [11] Method for controlling an electric vehicle comprising a power storage device, a first electric motor, a power transmission device and a charging device, wherein the power storage device is configured to store electrical power used to drive the vehicle, the first electric motor is configured to receive electrical power from the power storage device and to generate power, the power transmission device is provided between the first electric motor and drive wheels, wherein the power transmission device is configured to selectively allow and prevent power transmission between the first electric motor and the drive wheels, wherein the first electric motor is configured to be cooled by the lubricant of the power transmission device, and the charging device is configuredto charge the power storage device using a power supply located outside the vehicle, the method comprising: , Determine whether the lubricant temperature is lower than a predetermined temperature at a given time during the charging of the power storage device using the charging device; Determine whether the power transmission device is in a power-locked state, in which power transmission is suppressed; and Performing a warm-up control to increase the temperature of the lubricant by rotating the first electric motor when it is determined that the temperature of the lubricant is lower than the predetermined temperature at the time of executing the charging of the power storage device, and it is determined that the power transmission device is in the state of power shut off.