JP5409508B2 - Control system and control method for hybrid vehicle - Google Patents

Description

  The present invention relates to a control system and a control method for controlling a power generation amount of a hybrid vehicle that is driven using at least one of an engine and a motor generator as a drive source.

  Conventionally, a hybrid vehicle equipped with an engine and a traveling motor and driving wheels using at least one of the engine and the traveling motor as a drive source has been considered and implemented. Further, in such a hybrid vehicle, it is considered that the engine is driven near the highest efficiency point where fuel efficiency is highest, and further improvement of fuel efficiency is considered. For example, FIG. 6 is a diagram illustrating an example of an equal fuel consumption rate curve and an equal torque curve of an engine in a conventional hybrid vehicle. When the engine is operated near the maximum efficiency point indicated by the point Q in FIG. 6, the engine speed is set to a predetermined speed RE and the intake pipe pressure is set to a predetermined pressure PE.

  Patent Document 1 describes a method for controlling the power generation amount of a motor generator in a hybrid vehicle including a motor generator having functions as a motor and a generator. The motor generator generates power by being given the driving force of the engine. In this control method, control is performed so as to correct the power generation amount of the motor generator, reflecting the mechanical loss of the drive system from the engine to the transmission. The mechanical loss is obtained from the oil temperature of the transmission oil indicated by the oil temperature signal of the transmission. According to the above control method, by reducing the power generation amount during cold when the mechanical loss is large, the sum of the mechanical loss and the power generation amount is kept constant, and the same vehicle speed and the same accelerator pedal operation amount are maintained regardless of the outside air temperature. On the other hand, the same running torque can be secured. In addition, it is said that the engine can be driven near the maximum efficiency point to improve fuel efficiency.

  Patent Document 2 describes a control device for a motor generator mounted on an electric vehicle such as a hybrid vehicle. In this control device, a loss characteristic line indicating a correspondence relationship between the motor rotation speed and the output torque in each motor loss power is mapped in advance using the motor loss power as a parameter. Then, an allowable power loss value is set for the power loss related to the amount of heat generated by the motor generator with respect to the motor temperature. Then, according to the loss characteristic line corresponding to the allowable power loss value, the motor generator torque upper limit value for each rotational speed is set, and the torque command value is set.

JP 2008-137518 A JP 2008-211861 A

  In the hybrid vehicle power generation amount control method described in Patent Document 1, the loss of the motor generator, which changes according to the temperature of the motor generator that is an electric motor, is not considered. That is, the loss of the motor generator changes according to the running state and temperature. On the other hand, the control method described in Patent Document 1 that controls the power generation amount of the motor generator without considering this loss is improved from the viewpoint of optimizing the power generation amount and improving the fuel consumption and drivability of the vehicle. There is room for.

  On the other hand, in the case of the motor generator control device described in Patent Document 2, a loss power allowable value corresponding to the motor temperature is set, and the motor generator is controlled according to the loss characteristic line corresponding to the loss power allowable value. Torque upper limit value is set. However, the setting is made in order to ensure the output in a range where the motor generator does not reach an overheated state. In such a control device of Patent Document 2, it is not taken into consideration that the loss of the motor generator is accurately obtained regardless of changes in the temperature of the motor generator and the running state of the vehicle. That is, this control device has room for improvement from the viewpoint of optimizing the power generation amount and improving the fuel efficiency and drivability of the vehicle.

  An object of the present invention is to improve the fuel efficiency and drivability of a vehicle in a hybrid vehicle control system and control method regardless of changes in the temperature of a motor generator and the running state of the vehicle.

A control system for a hybrid vehicle according to the present invention is a motor generator driven by the power of an engine and a secondary battery, the motor generator generating electric power by being driven by the engine and supplying the generated power to the secondary battery And a control system for controlling the power generation amount of the hybrid vehicle driven by using at least one of the engine and the motor generator as a drive source, the temperature detection means for detecting the temperature of the motor generator, and the current running state of the vehicle a traveling estimating means for estimating a running state of the vehicle, and the temperature of the motor generator, a storage means for storing a loss relationship between loss of motor generator including iron loss and copper loss, and the temperature detection value of the motor generator, From the estimated current vehicle running state, based on the loss relationship stored in the storage means A hybrid vehicle comprising: a loss acquisition unit that acquires a loss of a motor generator; and a power generation control unit that calculates a power generation amount target value of the motor generator using the acquired loss of the motor generator and controls a power generation amount of the motor generator. Control system.

  In the hybrid vehicle control system according to the present invention, it is preferable that the storage unit stores a map representing a relationship between the vehicle running state and the motor generator temperature and the motor generator loss as the loss relationship.

  Preferably, in the hybrid vehicle control system according to the present invention, the storage unit stores an urban travel loss map and a high-speed travel loss map in which the travel state of the vehicle is different, and the urban travel loss map is an The relationship between the temperature and loss of the motor generator during traveling is represented, the high-speed traveling loss map represents the relationship between the temperature and loss of the motor generator during high-speed traveling of the vehicle, and the loss acquisition means is the estimated current vehicle traveling state Based on the above, the map to be read from the storage means is selected, and the loss of the motor generator is acquired from the selected map and the temperature detection value of the motor generator.

  In the hybrid vehicle control system according to the present invention, preferably, a speed detection means for detecting the speed of the vehicle, a vehicle speed distribution at a predetermined time set in advance, and a vehicle speed median in the speed distribution are obtained. And a speed distribution acquisition means for acquiring a relation value of speed variation, and the travel estimation means is configured to obtain a current value based on a preset estimation condition from a relation value of the obtained vehicle median speed and speed dispersion. It is estimated whether the vehicle running state is an urban running state or a high-speed running state.

  In the hybrid vehicle control system according to the present invention, preferably, an acceleration instruction amount detection means for detecting an acceleration instruction amount of the vehicle, a speed detection means for detecting the speed of the vehicle, an acceleration instruction amount of the vehicle, and a vehicle speed. Engine for driving the engine in the vicinity of the highest efficiency point where the fuel efficiency is highest when a predetermined efficiency driving condition is satisfied, and calculating a required driving output based on The power generation control means calculates a power generation target value by subtracting the sum of the required travel output and the loss of the motor generator from the engine output at the highest efficiency point.

Also, the hybrid vehicle control method according to the present invention is an engine and a motor generator driven by the power of the secondary battery, which generates power by being driven by the engine and supplies the generated power to the secondary battery. A control method for controlling a power generation amount of a hybrid vehicle that is driven by using at least one of the engine and the motor generator as a main drive source, the step of detecting the temperature of the motor generator, and the current vehicle running Based on the loss relationship stored in the storage means, the state of estimating the state, and the loss relationship between the vehicle running state , the temperature of the motor generator, and the loss of the motor generator including iron loss and copper loss, Based on the detected temperature value of the motor generator and the estimated current vehicle running state, the motor generator Acquiring loss, it calculates a power generation amount target value of the motor generator by using the loss of acquired motor generator, a control method of a hybrid vehicle and controlling the power generation amount of the motor generator.

  According to the control device and the control method for a hybrid vehicle according to the present invention, it is possible to accurately obtain the loss of the motor generator corresponding to the change in the temperature of the motor generator and the running state of the vehicle. For this reason, regardless of changes in the temperature of the motor generator and the running state of the vehicle, the loss of the motor generator is accurately obtained, and the power generation amount is controlled from the loss, so that the power generation amount can be optimized. As a result, the fuel efficiency and drivability of the vehicle can be improved regardless of changes in the temperature of the motor generator and the running state of the vehicle.

1 is a schematic diagram showing a configuration of an example hybrid vehicle according to an embodiment of the present invention. It is a block diagram which shows the structure of the control part of FIG. It is a figure which shows an example of the experimental result showing the relationship between the motor temperature at the time of urban driving | running | working, and loss. It is a figure which shows an example of the experimental result showing the relationship between the motor temperature at the time of high speed driving | running | working, and loss. It is a flowchart which shows the control method of the hybrid vehicle of FIG. It is a figure which shows an example of the equal fuel consumption rate curve and equal torque curve of the engine in the conventional hybrid vehicle.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. 1 to 5 show an example of an embodiment of the present invention.

  The hybrid vehicle control system according to the present embodiment is mounted on the hybrid vehicle and used to control the motor generator and the engine. As shown in FIG. 1, the hybrid vehicle 10 includes a control system 12, a power split mechanism 14, and wheels 18 connected to the drive shaft 16. The control system 12 includes an engine 20, a first motor generator (MG1) 22 driven by the engine 20 and mainly used as a generator, and a second motor generator (MG2) 24 mainly used as a running motor. And a control unit 28.

  FIG. 1 shows a case where the hybrid vehicle 10 is an FF vehicle that is a front-wheel drive vehicle with a front engine. However, the hybrid vehicle may be an FR vehicle that is a rear wheel drive vehicle with a front engine, a 4WD vehicle that is a four wheel drive vehicle, or the like.

  The power split mechanism 14 can split the power from the engine 20 into a path to the drive shaft 16 and a path to the first motor generator 22. The power split mechanism 14 is constituted by, for example, a planetary gear mechanism. For example, the rotating shaft of the first motor generator 22 is hollow, and the sun gear of the planetary gear mechanism is connected to the end of the rotating shaft. Further, the carrier connected to the planetary gear of the planetary gear mechanism is connected to the drive shaft of the engine 20 inserted through the inside of the rotation shaft of the first motor generator 22. Further, the output shaft 30 is connected to the ring gear of the planetary gear mechanism, and the rotation shaft of the second motor generator 24 is connected to the output shaft 30 directly or via a speed reducer such as another planetary gear mechanism (not shown). The output shaft 30 is connected to the drive shaft 16 connected to the wheel 18 via the speed reducer 32. The power split mechanism 14 can also be connected to the drive shaft of the engine 20 via a damper (not shown).

  The first motor generator 22 is a three-phase AC motor and can also be used as a starting motor for the engine 20. However, when the first motor generator 22 is used as a generator driven by the engine 20, the engine 20, at least a part of the torque transmitted through the carrier of the planetary gear mechanism is transmitted to the rotating shaft of the first motor generator 22 through the sun gear.

  The second motor generator 24 is a three-phase AC motor for generating a driving force of the vehicle, and can also be used as a generator, that is, for power regeneration.

  The rotation of the engine 20 is extracted to the output shaft 30 side and the first motor generator 22 side via the power split mechanism 14. The electric power generated by driving the first motor generator 22 is charged in a battery 34 that is a secondary battery. The configuration of the hybrid vehicle 10 is not limited to such a configuration, and is a motor generator driven by the power of the engine and the secondary battery, and generates secondary power by being driven by the engine. Various configurations can be adopted as long as they have a configuration of a hybrid vehicle that includes a motor generator that supplies generated power to the battery and drives at least one of the engine and the motor generator as a drive source. When the hybrid vehicle 10 is configured as an FR vehicle, the rotation of the output shaft 30 is transmitted to the rear wheels via the propeller shaft and the differential gear, thereby driving the rear wheels.

  The control system 12 includes the motor generators 22 and 24 and the control unit 28, the first inverter 36 for the first motor generator 22, the second inverter 38 for the second motor generator 24, and the first inverter. 36, a DC / DC converter (not shown) connected between the second inverter 38 and the battery 34, a temperature sensor 40 for detecting the temperature of the second motor generator 24, and an operation amount of an acceleration instruction unit such as an accelerator pedal, That is, it includes an accelerator operation amount sensor 42 that detects an accelerator operation amount that is an acceleration instruction amount, a vehicle speed sensor 44 that detects a vehicle speed, and a battery sensor 46 that detects a charge amount of a battery 34. For example, the battery sensor 46 includes a current sensor.

  The DC / DC converter is provided between the battery 34 and the first inverter 36 and the second inverter 38. The DC / DC converter includes two switching elements such as IGBTs and transistors connected in series, two diodes connected in antiparallel to each switching element, and a reactor having one end connected between each switching element. The other end of the reactor is connected to the battery 34. The DC / DC converter can boost the DC voltage supplied from the battery 34 and supply it to the first inverter 36 and the second inverter 38. Further, the DC / DC converter has a function of stepping down a DC voltage supplied from one or both of the two inverters 36 and 38 and supplying DC power to the battery 34, that is, charging the battery 34. The DC / DC converter is controlled by the control unit 28.

  The battery 34 is a secondary battery such as a nickel metal hydride battery or a lithium ion battery. A system relay (not shown) is provided between the battery 34 and the DC / DC converter, and the system relay is controlled to be turned on or off by the control unit 28. That is, when a start switch (not shown) is turned on by the user, the control unit 28 is activated, the control unit 28 turns on the system relay, and the DC voltage of the battery 34 is input to the input side of the first inverter 36 and the second inverter 38. Supplied to the terminal. When the start switch is turned off, the system relay is turned off, and the connection between the battery 34 and the first inverter 36 and the second inverter 38 is cut off.

  Further, the inverters 36 and 38 include U, V, and W phase arms. Each arm includes two switching elements such as IGBTs and transistors connected in series, and the center point of each arm is one end of a three-phase coil (not shown) constituting the corresponding motor generator 22 (or 24). Connected to each. The two inverters 36 and 38 are connected in parallel to the battery 34. In each motor generator 22, 24, the other ends of the three-phase coils are connected to each other at a neutral point.

  Each of the inverters 36 and 38 receives a control signal corresponding to the torque command value from the control unit 28, thereby controlling the switching of each switching element. For example, the first inverter 36 converts the DC voltage input from the battery 34 side into an AC voltage based on a signal corresponding to the torque command value input from the control unit 28 and drives the first motor generator 22. . In addition, when the first motor generator 22 generates power as the engine 20 is driven, the first inverter 36 converts the AC voltage obtained by the power generation into a DC voltage by the first inverter 36 and converts the AC voltage. DC voltage is supplied to the DC / DC converter. The DC / DC converter steps down the supplied DC voltage and then supplies it to the battery 34 to charge the battery 34.

  On the other hand, the second inverter 38 converts the DC voltage input from the battery 34 side into an AC voltage based on a signal corresponding to the torque command value input from the control unit 28, thereby generating a second motor generator. 24 is driven. Further, the second inverter 38 converts the AC voltage generated by the second motor generator 24 into a DC voltage during regenerative braking of the hybrid vehicle 10, and supplies the converted DC voltage to the DC / DC converter. The DC / DC converter steps down the supplied DC voltage and then supplies it to the battery 34 to charge the battery 34. The regenerative braking is executed when the accelerator pedal of the vehicle is not depressed and the charge amount of the battery 34 is small, and the second motor generator 24 is set in the regenerative braking state.

  Further, after the engine 20 is started, the second motor generator 24 gives a driving force so as to rotate the output shaft 30 in the same direction as the rotation direction of the engine so that the engine 20 performs torque assist, and the engine 20 The driving force is applied to the output shaft 30, the second motor generator 24 is driven by the output shaft 30, and the regenerative state in which the second motor generator 24 generates electric power can be switched. That is, when the engine 20 is driven, the second motor generator 24 enters a power running state so as to perform torque assist, so that a desired wheel driving force can be obtained and the engine 20 can be driven in an efficient state. . For example, as shown in FIG. 6 above, the engine 20 can be driven in the vicinity of the highest efficiency point Q (see FIG. 6) where the fuel efficiency is highest, and the fuel consumption of the engine 20 can be reduced. In addition, the power generated when the second motor generator 24 generates power by driving the engine 20 is also supplied to the battery 34, and the battery 34 is charged.

  For example, the control unit 28 causes the second motor generator 24 to output the engine 20 when the required travel output, which is an output required for the entire vehicle when the vehicle travels, is equal to or higher than the output of the engine 20 at the highest efficiency point. The second motor generator 24 is controlled to perform torque assist for assisting output. Further, the control unit 28 inputs the output of the engine 20 to the second motor generator 24 when the required travel output is lower than the output of the engine 20 at the highest efficiency point. That is, the second motor generator 24 is driven by the output of the engine 20 to generate power. In this case, as will be described later, the control unit 28 determines the required travel output based on the travel state of the vehicle, and calculates the required travel output and the loss of the second motor generator 24 from the output of the engine 20 at the highest efficiency point. Is subtracted to determine the target power generation amount of the second motor generator 24. As described above, the second motor generator 24 is driven by the electric power of the battery 34, generates electric power when driven by the engine 20, and supplies the generated electric power to the battery 34.

  The control unit 28 includes a microcomputer having a CPU, a memory, and the like, and may include, for example, a motor controller called a motor ECU and an engine controller called an engine ECU. In the illustrated example, only one control unit 28 is illustrated as the control unit 28, but the control unit 28 may be appropriately divided into a plurality of components and connected to each other. For example, the control unit 28 may be divided into a part having a function of a motor controller, a part having a function of an engine controller, and an overall control part that collectively controls the whole called a hybrid ECU, and may be connected to each other. .

  The control unit 28 also receives detection signals for calculating torque command values of the motor generators 22 and 24 such as detection signals of the accelerator operation amount sensor 42 and the vehicle speed sensor 44 and the power generation amount. The control unit 28 also receives detection signals from a temperature sensor 40 that detects the temperature of the second motor generator 24 and a battery sensor 46 that detects the amount of charge of the battery 34. In addition, the control unit 28 includes motor current values flowing through coils of the respective phases of the motor generators 22 and 24 detected by current sensors (not shown) provided in the first motor generator 22 and the second motor generator 24, A signal indicating the rotation angle of the motor generators 22 and 24 is also input.

  The control unit 28 outputs a control signal to the second inverter 38 according to the calculated second motor torque command value, and turns on or off the switching elements constituting the second inverter 38 according to the control signal, that is, a switching operation. Then, the second motor generator 24 is driven so that the torque according to the torque command value is output in the second motor generator 24. Similarly, the control unit 28 outputs a control signal to the first inverter 36, performs switching operation of the switching elements constituting the first inverter 36 in accordance with the control signal, and the first motor generator 22 calculates The first motor generator 22 is driven so that torque according to the one-motor torque command value is output. Such a hybrid vehicle 10 is driven using at least one of the engine 20 and the second motor generator 24 as a drive source.

  As shown in FIG. 2, the control unit 28 includes a storage unit 48 and an engine control unit 50. The storage means 48 stores a maximum efficiency operation control program, a travel torque calculation program, a travel state detection program, a motor loss calculation program, and a power generation control program. In the following description, the same elements as those shown in FIG. Further, the engine control means 50 outputs a fuel injection signal to the fuel injection valve of the engine 20 and outputs an ignition pulse signal that is an ignition signal to the ignition plug of the engine 20. Control ignition timing. Further, the engine control means 50 controls the fuel injection amount and ignition timing of the engine 20 when a preset efficiency operation condition is satisfied, and drives the engine 20 in the vicinity of the maximum efficiency point where fuel efficiency is highest. . The maximum efficiency operation control program controls the fuel injection amount and ignition timing of the engine 20 by the engine control means 50 when the preset efficiency operation condition is satisfied, so that the engine 20 has the highest fuel efficiency efficiency. Drive near the efficiency point.

  The control unit 28 includes a required output calculation unit 52, a speed distribution acquisition unit 54, a travel estimation unit 56, a loss acquisition unit 58, a power generation control unit 60, and a torque assist control unit 62. The required output calculation program calculates the required travel output by the required output calculation means 52 based on the signal indicating the acceleration instruction amount of the vehicle and the signal indicating the speed of the vehicle. That is, the required output calculation means 52 calculates the required travel output based on the vehicle acceleration instruction amount and the vehicle speed. More specifically, the required output calculation means 52 represents the accelerator operation amount Am and the vehicle speed V represented by an accelerator operation amount signal that is a detection signal of the accelerator operation amount sensor 42 and a vehicle speed signal that is a detection signal of the vehicle speed sensor 44. The corresponding required travel output RP is acquired from the request output map stored in the storage means 48 in advance, that is, the corresponding required travel output RP is calculated. For this purpose, the storage means 48 stores a map representing the relationship between the accelerator operation amount Am and the required travel output RP corresponding to the vehicle speed V as the required output map.

  The running state detection program estimates the current running state of the vehicle by the speed distribution acquisition unit 54 and the running estimation unit 56 based on the vehicle speed signal from the vehicle speed sensor 44. For example, the speed distribution acquisition unit 54 acquires a vehicle speed distribution at a predetermined time set in advance using a vehicle speed signal, and further acquires a vehicle speed median value and a speed variation relation value in the speed distribution. That is, calculate. Further, the travel estimation unit 56 determines whether the current vehicle travel state is an urban travel state and a high-speed travel state based on a preliminarily set estimation condition based on the acquired relationship value between the vehicle median speed and the speed variation. Estimate where it is. For example, as the first estimation condition, when it is established that the median speed is equal to or less than the set speed and the speed variation, for example, 3σ is equal to or greater than the set speed variation, it is estimated that the vehicle is in an urban driving state. Further, as a second estimation condition, when it is established that the median speed is equal to or higher than the set speed and the speed variation, for example, 3σ is equal to or smaller than the set speed variation, it is estimated that the vehicle is in a high speed running state. Further, as the establishment of the third estimation condition, the other cases are estimated as one state set in advance among the urban traveling state and the high-speed traveling state.

  The motor loss calculation program calculates the loss of the second motor generator 24 by the loss acquisition means 58 from the temperature detection value of the second motor generator 24 and the current vehicle running state estimated by the travel estimation means 56. Obtained based on the loss relationship stored in the storage means 48. That is, the loss acquisition means 58 stores the loss of the second motor generator 24 in the storage means 48 from the temperature detection value of the second motor generator 24 and the current vehicle running state estimated by the travel estimation means 56. Acquired based on the loss relationship. For this purpose, the storage means 48 stores a motor loss map representing the relationship between the running state of the vehicle, the temperature of the second motor generator 24, and the loss of the second motor generator 24 as a loss relationship.

  That is, in the present embodiment, the power generation target value or the assist output target value of the second motor generator 24 is calculated in consideration of the loss corresponding to the temperature of the second motor generator 24, which varies greatly depending on the traveling state of the vehicle. Then, the power generation amount of the second motor generator 24 is controlled, or the assist torque is output. The reason for considering such motor loss is as follows. In other words, it has been found that the loss of the motor (in other words, efficiency) varies with the temperature of the motor. In this case, the relationship between the motor temperature and the loss also varies depending on the traveling state of the vehicle.

  Specifically, the power loss, which is the motor loss, is mainly represented by the sum of the copper loss caused by the motor current and the iron loss caused by the eddy current generated in the motor core. Further, when the vehicle is traveling at a high speed, the speed of the motor is small and the motor rotates at a high speed. Therefore, the motor iron loss is dominant among the motor losses. In this case, it is known that the motor loss decreases as the motor temperature increases. On the other hand, when the vehicle is traveling in an urban area where acceleration / deceleration is frequently repeated, the torque often increases at a relatively low speed in the motor, and the copper loss is dominant among the motor losses. In this case, it has been found that the motor loss increases as the motor temperature increases. Conventionally, the relationship between the motor temperature and the motor loss that change according to the running state of the vehicle has not been considered. For this reason, conventionally, there has been room for improvement in terms of obtaining this loss accurately and optimally controlling the power generation amount and assist torque of the motor. That is, conventionally, there has been room for improvement in terms of calculating an optimum power generation amount target value and charging the battery with a sufficient amount of power generation. If the charge amount of the battery decreases during traveling, the necessary assist torque of the motor cannot be obtained effectively, and drivability may be reduced. Therefore, conventionally, there has been room for improvement from the viewpoint of improving fuel consumption and drivability regardless of the temperature of the motor generator and the running state of the vehicle. The present embodiment has been invented to improve such a room for improvement.

  In other words, in the present embodiment, the storage means 48 stores a loss, which is a relationship between the running state of the vehicle, the temperature of the second motor generator 24 and the loss of the second motor generator 24 (hereinafter referred to as “motor loss”). I remember the relationship. More specifically, the storage means stores at least two types of motor loss maps, ie, “city road loss map” and “high speed road loss map”, as loss relationships. The “city driving loss map” represents the relationship between the temperature of the second motor generator 24 and the motor loss when the vehicle is driving in the city. The “high speed travel loss map” represents the relationship between the temperature of the second motor generator 24 and the motor loss when the vehicle travels at a high speed.

  FIG. 3 is a diagram showing an example of an experimental result representing the relationship between motor temperature and loss during urban driving, and FIG. 4 is an example of an experimental result representing the relationship between motor temperature and loss during high-speed traveling. FIG. In the following description, the same elements as those shown in FIGS. As shown in FIG. 3, when driving in an urban area, the torque and rotation speed of the second motor generator 24 change frequently, so copper loss is dominant among motor losses, and the temperature of the second motor generator 24 is high. As a result, the motor loss increases. On the other hand, as shown in FIG. 4, during high-speed running, the torque and the rotational speed of the second motor generator 24 are kept so as to reduce variation, so iron loss is dominant among motor losses. Thus, the motor loss decreases as the temperature of the second motor generator 24 increases. In the present embodiment, the motor loss is corrected using a map obtained from such experimental results and representing the relationship between the temperature of the second motor generator 24 and the motor loss in accordance with the running state, 2 The target value of the power generation amount or assist output amount of the motor generator 24 is corrected.

  That is, the loss acquisition means 58 selects a map to be read out from the two types of motor loss maps stored in the storage means 48 based on the current vehicle travel state estimated by the travel estimation means 56 and selects the selected 1 From the motor loss map, the motor loss is acquired based on the temperature detection value of the second motor generator 24. For example, when the estimated vehicle running state is changed, the motor loss map to be used is switched.

  Further, the power generation control program calculates a power generation target value of the second motor generator 24 using the acquired motor loss by the power generation control means 60, and uses the power generation amount of the second motor generator 24 as the power generation target value. Control to be. That is, the power generation control means 60 calculates the power generation amount target value of the second motor generator 24 using the acquired motor loss, and controls the power generation amount of the second motor generator 24. More specifically, the power generation control means 60 subtracts the sum of the required travel output RP and the motor loss ML from the engine output RO at the highest efficiency point where the fuel efficiency of the engine 20 is the highest, and generates a power generation target value. G is calculated, and the power generation amount of the second motor generator 24 is controlled to be the power generation amount target value G, and the battery 34 is charged with the generated power. Each of the above programs may be sequentially activated each time the activation switch is turned on, or may be activated each time a preset condition is satisfied.

  Further, the torque assist control means 62 calculates the assist output target value PA by subtracting the engine output RO at the highest efficiency point from the sum of the respective required travel output RP and motor loss ML. The second motor generator 24 is controlled so that the second motor generator 24 outputs an assist torque target value TA corresponding to the assist output target value PA.

  Next, the hybrid vehicle control method of the present embodiment will be described with reference to the flowchart shown in FIG. This flowchart is executed by each program described above. First, in step S10 (hereinafter, “step S” is simply described as “S”), there are a vehicle speed signal, an accelerator operation amount signal, a battery charge amount detection signal, and a detected temperature signal of the second motor generator 24. The controller 28 accepts the input of the motor temperature signal. For example, a step of detecting the temperature of the second motor generator 24 by the temperature sensor 40 is performed, and an input of a motor temperature signal indicating the temperature is received by the control unit 28. Next, in S12, the required output calculating means 52 calculates the required travel output RP with reference to the above-mentioned required output map based on the vehicle speed V indicated by the vehicle speed signal and the accelerator operation amount Am indicated by the accelerator operation amount signal.

  Next, in S14, based on the vehicle speed V represented by the vehicle speed signal, a step of estimating the current traveling state of the vehicle is performed by the speed distribution acquisition unit 54 and the traveling estimation unit 56. For example, in this case, whether the current running state is an urban running state or a high-speed running state based on a speed median obtained from a speed distribution within a preset time and a speed variation such as 3σ. Is estimated.

  Next, in S16, a step of calculating the motor loss ML is performed based on the temperature detection value of the second motor generator 24 represented by the motor temperature signal and the running state estimated in S14. That is, the motor loss ML is calculated based on the temperature detection value of the second motor generator 24 and the motor loss map stored in the storage means 48 and corresponding to the running state estimated in S14.

  Next, in S18, it is determined whether or not the engine output RO at the highest efficiency point is larger than the sum of the required travel output RP and the motor loss ML (RO> RP + ML). If the determination in S18 is affirmative, the process proceeds to S20, and it is determined whether or not the battery charge amount E represented by the battery charge amount signal is less than a preset first predetermined value E1 (E <E1). . If the determination in S20 is affirmative, it is determined that the battery charge is low, and the process proceeds to S22.

In S22, the power generation control means 60 calculates the power generation target value G by subtracting the sum of the required travel output RP and the motor loss ML from the engine output RO at the highest efficiency point. That is, a step of calculating the power generation target value G by the following equation is performed.
G = RO− (RP + ML) (1)

  When calculating the power generation target value G, the mechanical loss DL in the drive element from the engine to the drive shaft 16 excluding the motor loss in the second motor generator 24 on the right side of the equation (1) is also calculated. Alternatively, it may be added as a subtraction amount (-DL).

  Next, in S24, the power generation control means 60 performs a step of charging the battery 34 by controlling the power generation amount of the second motor generator 24 by the second inverter or the like so that the power generation target value G is obtained. At the same time, it is determined that the determination of S18 and S20 is both affirmative, and the engine 20 is configured so that the engine output RO is output near the maximum efficiency point by the engine control means 50 as the establishment of the first efficiency operation condition. The highest-efficiency operation control that drives

  On the other hand, if the determination in S20 is negative, the process proceeds to S26, where the power generation of the second motor generator 24 and the maximum efficiency operation control of the engine 20 are stopped, for example, the required travel output only by the output of the engine 20 Alternatively, the value obtained by adding the mechanical loss to the required travel output is obtained, and the process returns to S10.

  On the other hand, if the determination in S18 is negative, the process proceeds to S28, and whether or not the battery charge amount E exceeds a preset second predetermined value E2 that exceeds the first predetermined value E1 (E> E2). Determine whether. If the determination in S28 is affirmative, it is determined that the battery charge amount is large, and the process proceeds to S30.

In S30, the torque assist control means 62 calculates the assist output target value PA by subtracting the engine output RO at the highest efficiency point from the sum of the required travel output RP and the motor loss ML. That is, the step of calculating the assist output target value PA by the following equation is performed.
PA = RP + ML-RO (2)

  When calculating the assist output target value PA, the mechanical loss DL in the drive element from the engine to the drive shaft 16 excluding the motor loss in the second motor generator 24 on the right side of the equation (2) is also calculated. , Or (+ DL) which is the addition amount.

  Next, in S32, the torque assist control means 62 causes the second motor generator 24, the second inverter 38, etc. to output the assist torque target value TA corresponding to the assist output target value PA from the second motor generator 24. Torque assist control controlled by For example, the assist torque target value TA is calculated based on the assist output target value PA and the rotation speed obtained from the rotation angle detection value of the second motor generator 24. At the same time, if the determination in S18 is negative and the determination in S28 is affirmative, the engine control RO 50 outputs the engine output RO in the vicinity of the maximum efficiency point, as the second efficiency operation condition is satisfied. Thus, the most efficient operation control for driving the engine 20 is performed.

  On the other hand, if the determination in S28 is negative, the process proceeds to S34, where the torque assist control of the second motor generator 24 and the maximum efficiency operation control of the engine 20 are stopped, for example, only requested by the output of the engine 20 The travel output or the value obtained by adding the mechanical loss to the requested travel output is obtained, and the process returns to S10.

  According to such a control system and control method, the motor loss ML corresponding to changes in the temperature of the second motor generator 24 and the running state of the vehicle can be obtained with high accuracy. Therefore, regardless of changes in the temperature of the second motor generator 24 and the running state of the vehicle, the motor loss ML is accurately obtained, the power generation amount target value G is corrected from the loss ML, and the power generation amount is controlled. The amount of power generation can be optimized. As a result, the fuel efficiency of the vehicle can be improved regardless of changes in the temperature of the second motor generator 24 and the running state of the vehicle, and the assist torque necessary for the second motor generator 24 can be effectively output, improving drivability. I can plan. In particular, the present embodiment is effective because the motor loss ML can be reduced when the urban travel loss map is used in a low-temperature environment, and the power generation amount can be optimized more effectively.

  Moreover, when obtaining the torque assist amount of the second motor generator 24, the motor loss ML corresponding to the change in the temperature of the second motor generator 24 and the running state of the vehicle is obtained, and the assist output target value PA is obtained from the loss ML. Is corrected and the torque assist amount is controlled, so that further improvement in fuel consumption and drivability can be achieved.

  In the present embodiment, the loss acquisition means 58 acquires the motor loss ML using a motor loss map as the loss relationship. However, the storage means stores a relational expression representing the relation between the temperature of the second motor generator 24 and the motor loss ML, which is different depending on the traveling state of the vehicle, as the loss relation. It is also possible to employ a configuration in which the motor loss ML is calculated, that is, acquired based on the temperature of the two motor generators 24.

  In the above embodiment, the case where the motor generator that controls the power generation amount by the power generation control unit is the second motor generator has been described. However, the present invention is not limited to such a configuration. For example, when the first motor generator is to have the function of the second motor generator when the second motor generator fails, the power generation control means is provided. The motor generator that controls the amount of power generated by the above can be used as the first motor generator.

  DESCRIPTION OF SYMBOLS 10 Hybrid vehicle, 12 Control system, 14 Power split mechanism, 16 Drive shaft, 18 wheels, 20 Engine, 22 1st motor generator (MG1), 24 2nd motor generator (MG2), 28 Control part, 30 Output shaft, 32 Reduction gear, 34 battery, 36 1st inverter, 38 2nd inverter, 40 temperature sensor, 42 accelerator operation amount sensor, 44 vehicle speed sensor, 46 battery sensor, 48 storage means, 50 engine control means, 52 required output calculation means, 54 Speed distribution acquisition means, 56 travel estimation means, 58 loss acquisition means, 60 power generation control means, 62 torque assist control means.

Claims (8)

Engine,
A motor generator driven by the power of the secondary battery, the motor generator generating power by being driven by the engine, and supplying the generated power to the secondary battery,
A control system for controlling a power generation amount of a hybrid vehicle that drives using at least one of an engine and a motor generator as a drive source,
Temperature detection means for detecting the temperature of the motor generator;
Traveling estimation means for estimating the current traveling state of the vehicle;
And running state of the vehicle, and the temperature of the motor generator, a storage means for storing a loss relationship between loss of motor generator including iron loss and copper loss,
Loss acquisition means for acquiring the loss of the motor generator based on the loss relationship stored in the storage means from the detected temperature value of the motor generator and the estimated current vehicle running state;
A hybrid vehicle control system comprising: a power generation control unit that calculates a power generation amount target value of the motor generator using the acquired loss of the motor generator and controls the power generation amount of the motor generator. In the hybrid vehicle control system according to claim 1,
The travel estimation means estimates whether the current travel state of the vehicle is a travel state in which the copper loss is dominant among the losses of the motor generator or a travel state in which the iron loss is dominant. A control system for a hybrid vehicle. In the hybrid vehicle control system according to claim 1 or 2 ,
The storage means stores, as the loss relationship, a map representing the relationship between the vehicle running state and the motor generator temperature and the motor generator loss. In the hybrid vehicle control system according to claim 3 ,
The storage means stores an urban travel loss map and a high-speed travel loss map in which the traveling state of the vehicle is different,
The city driving loss map represents the relationship between the temperature and loss of the motor generator when the vehicle is driving in the city,
The high-speed travel loss map represents the relationship between the motor generator temperature and loss when the vehicle is traveling at high speed.
The loss acquisition means selects a map to be read from the storage means based on the estimated current vehicle running state, and acquires the loss of the motor generator from the selected map and the temperature detection value of the motor generator. A hybrid vehicle control system. In the control system of the hybrid vehicle according to any one of claims 1 to 4 ,
Speed detecting means for detecting the speed of the vehicle;
A speed distribution acquisition means for acquiring a speed distribution of the vehicle at a predetermined time set in advance, and acquiring a relational value between the vehicle speed median and the speed variation in the speed distribution;
The travel estimation means determines whether the current vehicle travel state is either an urban travel state or a high-speed travel state based on a pre-established estimation condition based on the acquired relationship value between the median speed of the vehicle and the speed variation. A control system for a hybrid vehicle characterized by estimating the above. In the hybrid vehicle control system according to any one of claims 1 and 5 ,
An acceleration instruction amount detection means for detecting an acceleration instruction amount of the vehicle;
Speed detecting means for detecting the speed of the vehicle;
Request output calculation means for calculating the required travel output based on the acceleration command amount of the vehicle and the speed of the vehicle, and calculating the required travel output;
Engine control means for driving the engine in the vicinity of the highest efficiency point where the fuel efficiency is highest when a preset efficiency driving condition is established,
The power generation control means calculates the power generation target value by subtracting the sum of the required travel output and the loss of the motor generator from the engine output at the highest efficiency point. Engine,
A motor generator driven by the power of the secondary battery, the motor generator generating power by being driven by the engine, and supplying the generated power to the secondary battery,
A control method for controlling a power generation amount of a hybrid vehicle that drives with at least one of an engine and a motor generator as a main drive source,
Detecting the temperature of the motor generator;
Estimating the current vehicle running state;
A has been lost relationship stored in the storage means, and running state of the vehicle, and the temperature of the motor-generator, based on the loss relationship between loss of motor generator including iron loss and copper loss, and the temperature detection value of the motor-generator Obtaining the loss of the motor generator from the estimated current vehicle running state;
A method for controlling a hybrid vehicle, comprising: calculating a power generation amount target value of the motor generator using the acquired loss of the motor generator, and controlling the power generation amount of the motor generator. The hybrid vehicle control method according to claim 7,
The step of estimating the running state of the current vehicle is based on whether the current running state of the vehicle is a running state where the copper loss is dominant or the running state where the iron loss is dominant among the losses of the motor generator. A control method for a hybrid vehicle characterized by estimating whether

Images