JP2012153192A - Hybrid vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an EV range that drives a vehicle only by a motor.SOLUTION: A hybrid vehicle 100 includes an engine 1 and a motor 2 as power sources. The controller of the hybrid vehicle 100 includes: a waste heat regeneration apparatus 6 that regenerates waste heat of the engine 1 as regenerative power, and regenerative power transmitting mechanisms (11, 12, 663) for transmitting the regenerative power regenerated by the waste heat regeneration apparatus 6 to an output shaft 13 of the engine 1 during EV drive mode in which only the motor 2 is used as a power source. During the EV drive mode, the regenerative power regenerated by the waste heat regeneration apparatus 6 idles the output shaft of the engine 1. The engine 1 self-starts without cranking using the motor 2. There is no need to leave power for restarting the engine during the EV drive mode, thereby increasing the range where only the motor 2 is used for traveling.

Description

  The present invention relates to a control device for a hybrid vehicle.

  A conventional control device for a hybrid vehicle cranks a stationary engine with a motor and restarts the engine. For this reason, during EV traveling, the motor is driven within a limited torque range that leaves a surplus force for smoothly restarting the engine.

JP 2005-117779 A

  As described above, the conventional hybrid vehicle control device described above has a problem in that the region in which the vehicle can travel only by the motor is small because the motor output cannot be increased to the maximum torque during EV traveling.

  The present invention has been made paying attention to such problems, and an object of the present invention is to increase a region where the vehicle can travel only by a motor.

  The present invention is a control device for a hybrid vehicle including an engine and a motor as power sources. The hybrid vehicle control device regenerates the waste heat regeneration device that regenerates the waste heat of the engine as regenerative power, and the regenerative power that is regenerated by the waste heat regenerative device during EV traveling that uses only the motor as a power source. And a regenerative power transmission mechanism that transmits to the output shaft.

  According to the present invention, the output shaft of the engine can be idled by the regenerative power regenerated by the waste heat regeneration device during EV traveling. Therefore, it is possible to start the engine independently without performing cranking by the motor, and it is not necessary to leave a surplus power for restarting the engine during EV traveling. Therefore, it is possible to increase the area that can be traveled only by the motor.

FIG. 1 is a schematic configuration diagram of a hybrid vehicle according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of the Rankine cycle system. FIG. 3 is a map for selecting the target travel mode. FIG. 4 is a flowchart illustrating control of the hybrid vehicle according to the present embodiment. FIG. 5 is a flowchart for explaining EV traveling mode transition processing. FIG. 6 is a map for calculating the expander torque Tran. FIG. 7 is a table for calculating the friction torque Tfri. FIG. 8 is a flowchart for explaining EV travel mode processing. FIG. 9 is a table for setting the upper limit value of the motor torque during EV traveling. FIG. 10 is a flowchart illustrating HEV travel mode transition processing. FIG. 11 is a time chart showing the control operation of the hybrid vehicle according to the present embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a hybrid vehicle 100 according to an embodiment of the present invention.

  The hybrid vehicle 100 includes an engine 1 and a motor generator 2 as power sources, a battery 3 as a power source, an inverter 4 that controls the motor generator 2, and a plurality of power sources for transmitting the output of the power source to the rear wheels 57. A drive system 5 composed of parts, a Rankine cycle system 6 that regenerates the waste heat of the engine 1 as motive power, and a controller 7 for controlling the parts of the engine 1, the motor generator 2, the drive system 5, and the Rankine cycle system 6; .

  The engine 1 is a gasoline engine. A crank pulley 12 is provided at one end of the crankshaft 13 of the engine 1.

  The motor generator 2 is a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. The motor generator 2 has a function as an electric motor that rotates by receiving electric power supply, and a function as a generator that generates an electromotive force at both ends of the stator coil when the rotor is rotated by an external force.

  The battery 3 supplies electric power to various electrical components such as the motor generator 2 and stores the electric power generated by the motor generator 2.

  The inverter 4 is a current converter that mutually converts two types of electricity, DC and AC. The inverter 4 converts the direct current from the battery 3 into a three-phase alternating current having an arbitrary frequency and supplies it to the motor generator 2. On the other hand, when the motor generator 2 functions as a generator, the three-phase alternating current from the motor generator 2 is converted into direct current and supplied to the battery 3.

  The drive system 5 includes a first clutch 51, an automatic transmission 52, a second clutch 53, a propeller shaft 54, a final reduction differential device 55, and a drive shaft 56.

  First clutch 51 is provided between engine 1 and motor generator 2. The first clutch 51 is a wet multi-plate clutch capable of continuously changing the torque capacity by controlling the oil flow rate and hydraulic pressure by the first solenoid valve 511. The first clutch 51 is controlled in three states, that is, an engaged state, a slip state (half-clutch state), and a released state by changing the torque capacity.

  The automatic transmission 52 is a stepped transmission having seven forward speeds and one reverse speed. The automatic transmission 52 includes four sets of planetary gear mechanisms and a plurality of frictional engagement elements (three sets of multi-plate clutches, four sets) that are connected to a plurality of rotating elements constituting the planetary gear mechanism and change their linkage state. Multi-plate brake, two sets of one-way clutch). The gear position is switched by adjusting the hydraulic pressure supplied to each frictional engagement element and changing the engagement / release state of each frictional engagement element.

  The second clutch 53 is a wet multi-plate clutch that can continuously change the torque capacity by controlling the oil flow rate and hydraulic pressure by the second solenoid valve 531. The second clutch 53 is controlled in three states, that is, an engaged state, a slip state (half-clutch state), and a released state by changing the torque capacity. In the present embodiment, some of the plurality of frictional engagement elements provided in the automatic transmission 52 are used as the second clutch 53.

  The propeller shaft 54 connects the output shaft of the automatic transmission 52 and the input shaft of the final reduction differential 55.

  The final deceleration device 55 is an integration of the final deceleration device and the differential device, and transmits the rotation to the left and right drive shafts 56 after decelerating the rotation of the propeller shaft 54. Further, when it is necessary to cause a speed difference between the rotational speeds of the left and right drive shafts 56 such as during a curve run, the speed difference is automatically given to enable smooth running. Rear wheels 57 are attached to the front ends of the left and right drive shafts 56, respectively.

  The Rankine cycle system 6 is a system that recovers waste heat of the engine 1 from a coolant of the engine 1 to a refrigerant and regenerates the recovered waste heat as power. The Rankine cycle system 6 will be described in detail with reference to FIG. The waste heat of the engine 1 may be recovered not from the cooling water of the engine 1 but from exhaust gas.

  FIG. 2 is a schematic configuration diagram of the Rankine cycle system 6.

  As shown in FIG. 2, the Rankine cycle system 6 includes a refrigerant passage 61, a pump 62, an evaporator 63, a pressure sensor 64, an on-off valve 65, an expander 66, and a condenser 67.

  The refrigerant passage 61 is a passage through which the refrigerant circulates. The refrigerant passage 61 includes a first passage 61A that connects the pump 62 and the evaporator 63, a second passage 61B that connects the evaporator 63 and the expander 66, and a first passage that connects the expander 66 and the condenser 67. 3 passages 61 </ b> C, and a fourth passage 61 </ b> D that connects the condenser 67 and the pump 62. In the present embodiment, a refrigerant that evaporates at about 80 [° C.] to about 90 [° C.] is used as the refrigerant, but the evaporating temperature is not limited to this, and depends on the specification and purpose of the engine 1. The optimum one may be selected as appropriate.

  The pump 62 is an electric pump 62 and pumps a liquid refrigerant to the evaporator 63.

  The evaporator 63 performs heat exchange between the high-temperature cooling water after cooling the engine 1 and the liquid refrigerant pumped by the pump 62, and heats and vaporizes the liquid refrigerant.

  The pressure sensor 64 is provided in the second passage 61 </ b> B so as to be located upstream of the expander 66. The pressure sensor 64 detects the pressure of the refrigerant flowing through the second passage 61B (hereinafter referred to as “refrigerant pressure”).

  The on-off valve 65 is provided in the second passage 61 </ b> B so as to be located upstream of the expander 66. The on-off valve 65 is controlled by the controller 7 to open and close the second passage 61B. By opening the on-off valve 65, the refrigerant vaporized by the evaporator 63 flows into the expander 66.

  The expander 66 includes a rotating shaft 661, a turbine 662 provided at one end of the rotating shaft 661, and an expander pulley 663 (see FIG. 1) provided at the other end of the rotating shaft 661.

  The turbine 662 is a steam turbine that converts heat into rotational energy by expanding the refrigerant evaporated in the evaporator 63.

  The expander pulley 663 is mechanically connected to the crank pulley 12 via the belt 11. An electromagnetic clutch 664 is interposed between the expander pulley 663 and the rotary shaft 661 so that the expander 66 can be disconnected from the engine 1 as necessary.

  The condenser 67 exchanges heat between the gaseous refrigerant flowing into the condenser 67 and the outside air, and cools and liquefies the gaseous refrigerant. The refrigerant liquefied by the condenser 67 is again pumped to the evaporator 63 by the pump 62 and circulates in the refrigerant passage 61.

  The controller 7 is composed of a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface).

  The controller 7 detects various sensors for detecting the traveling state of the hybrid vehicle 100 such as an accelerator stroke sensor 60, a vehicle speed sensor 61, an engine rotation sensor 62, a motor generator rotation sensor 63, and an SOC (State Of Charge) sensor 64. A signal is input.

  The accelerator stroke sensor 60 detects the amount of depression of the accelerator pedal (hereinafter referred to as “accelerator operation amount”) as the target drive torque. The vehicle speed sensor 61 detects the vehicle speed of the hybrid vehicle 100. The engine rotation sensor 62 detects the rotation speed of the crankshaft 13 (hereinafter referred to as “engine rotation speed”). Motor generator rotation sensor 63 detects the rotation speed of motor generator 2 (hereinafter referred to as “motor rotation speed”). The SOC sensor 64 detects the battery storage amount.

  Then, the controller 7 selects either the EV (Electric Vehicle) travel mode or the HEV (Hybrid Electric Vehicle) travel mode as the target travel mode according to the detected travel state of the hybrid vehicle 100.

  The EV travel mode is a travel mode in which the first clutch 51 is released and the hybrid vehicle 100 is driven using only the motor generator 2 as a power source. The HEV travel mode is a travel mode in which the hybrid vehicle 100 is driven while the first clutch 51 is engaged and the engine 1 is included as a power source.

  FIG. 3 is a map for selecting the target travel mode based on the vehicle speed and the accelerator operation amount. This map is created in advance by a preliminary experiment or the like, and is stored in the controller 7.

  The target travel mode selection map includes a travel mode switching line from the EV travel mode to the HEV travel mode (hereinafter referred to as “engine start line”) indicated by a solid line, and a travel mode from the HEV mode to the EV mode indicated by a broken line. A switching line (hereinafter referred to as “engine stop line”) is set.

  When the current travel mode is the EV travel mode, if the operating point determined based on the vehicle speed and the accelerator operation amount is above the engine start line, the target travel mode is set to the HEV travel mode. On the other hand, if the operating point is below the engine start line, the target travel mode is set to the EV travel mode.

  When the current travel mode is the HEV travel mode, if the operating point is below the engine stop line, the target travel mode is set to the EV travel mode. On the other hand, if the operating point is above the engine stop line, the target travel mode is set to the HEV travel mode.

  Here, conventionally, when shifting from the EV traveling mode to the HEV traveling mode, the first clutch 51 is in a half-clutch state, and the engine 1 is cranked by the power of the motor generator 2 and restarted. At the start of cranking when the engine 1 is restarted, torque (hereinafter referred to as “starting torque”) necessary for rotating the stationary crankshaft 13 is input to the motor generator 2 as a load.

  Conventionally, therefore, the motor torque is increased by the starting torque when the engine is restarted so that the starting torque does not reduce the rotation speed of the output shaft of the motor generator 2 to cause a shock. For this reason, it is necessary to drive the motor generator 2 in the state where the remaining power is left for the starting torque in the EV traveling mode. In other words, the motor generator 2 can be driven only within the limit torque range obtained by subtracting the starting torque from the maximum torque that can be generated by the motor generator 2 (hereinafter referred to as “maximum motor torque”).

  Therefore, in the present embodiment, the crankshaft 13 of the engine 1 is rotated by the expander 66 during the EV traveling mode. This eliminates the need for cranking the engine 1 by the motor generator 2 when the engine is restarted, so that the motor torque can be increased to the maximum motor torque in the EV travel mode. As a result, the ratio of EV traveling during traveling can be increased as compared with the prior art, and fuel consumption can be improved. Hereinafter, control of the hybrid vehicle 100 according to this embodiment will be described.

  FIG. 4 is a flowchart illustrating control of the hybrid vehicle 100 according to the present embodiment. The controller 7 executes this routine at a predetermined calculation cycle (for example, 10 ms) while the hybrid vehicle 100 is traveling.

  In step S1, the controller 7 determines the current travel mode. If the current travel mode is the HEV travel mode, the controller 7 performs the process of step S2. On the other hand, if the current travel mode is the EV travel mode, the process of step S4 is performed.

  In step S2, the controller 7 refers to the target travel mode selection map of FIG. 3 and determines whether the target travel mode is the EV travel mode based on the vehicle speed and the accelerator operation amount. If the target travel mode is not the EV travel mode, the controller 7 ends the current process. On the other hand, if the target travel mode is the EV travel mode, the process of step S3 is performed.

  In step S3, the controller 7 performs a transition process from the HEV travel mode to the EV travel mode (hereinafter referred to as “EV mode transition process”). Details of the EV traveling mode transition process will be described later with reference to FIG.

  In step S4, the controller 7 refers to the target travel mode selection map of FIG. 3 and determines whether the target travel mode is the HEV travel mode based on the vehicle speed and the accelerator operation amount. If the target travel mode is not the HEV travel mode, the controller 7 performs the process of step S5. On the other hand, if the target travel mode is the HEV travel mode, the process of step S6 is performed.

  In step S5, the controller 7 performs an EV travel mode process. Details of the EV traveling mode process will be described later with reference to FIG.

  In step S6, the controller 7 performs a transition process from the EV travel mode to the HEV travel mode (hereinafter referred to as “HEV mode transition process”). Details of the HEV travel mode transition process will be described later with reference to FIG.

  FIG. 5 is a flowchart for explaining EV traveling mode transition processing.

  In step S31, the controller 7 refers to a map of FIG. 6 to be described later, and determines the torque of the expander 66 based on the rotation speed of the expander 66 (hereinafter referred to as “expander rotation speed”) Nran and the refrigerant pressure Pref. (Hereinafter referred to as “expander torque”) Tran is calculated.

  In step S32, the controller 7 refers to a table of FIG. 7 described later, and based on the engine water temperature, the absolute value of the negative torque (hereinafter referred to as “friction torque”) generated by the sliding friction between the parts constituting the engine 1. ) Calculate Tfri.

  In step S <b> 33, the controller 7 releases the first clutch 51 and stops the fuel supply to the engine 1.

  In step S <b> 34, the controller 7 determines whether or not to perform the idling operation of the engine 1 that drives the expander 66 to idle the engine 1. Specifically, it is determined whether or not the expander torque Tran is larger than the friction torque Tfri. If the expander torque Tran is larger than the friction torque Tfri, the controller 7 performs the process of step S35. On the other hand, if the expander torque Tran is equal to or less than the friction torque Tfri, the process of step S37 is performed.

  In step S35, the controller 7 opens the on-off valve 65 and engages the electromagnetic clutch 664. Thus, during EV traveling, the refrigerant circulates through the refrigerant passage 61 and the turbine 662 rotates, and the rotary shaft 661 and the expander pulley 663 rotate in conjunction with the rotation of the turbine 662. As a result, the crankshaft 13 is rotated via the belt 11 and the engine 1 rotates idle.

  In step S36, the controller 7 sets the travel mode to the EV travel mode.

  In step S37, the controller 7 closes the on-off valve 65 and releases the electromagnetic clutch 664. Thereby, the pressure of the 2nd channel | path 61B can be hold | maintained during EV driving | running | working. Therefore, if the on-off valve 65 is opened during HEV running after the engine is restarted, the turbine 662 can be rotated with the held pressure, so that the Rankine cycle system 6 can assist the power of the hybrid vehicle 100 more efficiently. Can do.

  FIG. 6 is a map for calculating the expander torque Tran based on the expander rotation speed Nran and the refrigerant pressure Pref. This map is created in advance by a preliminary experiment or the like, and is stored in the controller 7.

  As shown in FIG. 6, the expander torque Tran increases as the expander rotational speed Nran decreases and the refrigerant pressure Pref increases.

  FIG. 7 is a table for calculating the friction torque Tfri based on the engine coolant temperature. This table is created in advance by a preliminary experiment or the like, and is stored in the controller 7.

  As shown in FIG. 7, the friction torque increases as the engine water temperature decreases. This is because the lower the engine water temperature, the greater the viscosity of the lubricating oil supplied between the components constituting the engine 1.

  FIG. 8 is a flowchart for explaining EV travel mode processing.

  In step S51, the controller 7 reads the engine rotation speed Ne.

  In step S52, the controller 7 refers to a table of FIG. 9 described later, and sets the upper limit value of the motor torque during EV traveling based on the engine rotation speed Ne during EV traveling. The engine rotation speed Ne during EV traveling is calculated based on the expander rotation speed Nran and the pulley ratio determined from the pulley diameter of the expander pulley 663 and the pulley diameter of the crank pulley 12.

  In step S53, the controller 7 drives the motor generator 2 within a range that does not exceed the set upper limit value of the motor torque, and performs EV traveling.

  FIG. 9 is a table for setting the upper limit value of the motor torque during EV traveling based on the engine rotational speed Ne during EV traveling. This table is created in advance by a preliminary experiment or the like, and is stored in the controller 7.

  As shown in FIG. 9, if the engine rotational speed Ne during EV traveling is equal to or higher than the self-startable speed, the upper limit value of the motor torque is set to the maximum motor torque. The self-startable speed is a rotational speed at which the air-fuel mixture can be sucked and compressed, and the self-sustained operation of the engine 1 can be started by igniting the sucked and compressed air-fuel mixture. In this embodiment, the speed is set to 200 [rpm], but is not limited to this, and may be set as appropriate according to the engine 1 specifications.

  Then, the upper limit value of the motor torque is set to be smaller as the engine rotational speed Ne during EV traveling becomes lower than the self-startable speed. This is because if the engine rotational speed Ne during EV traveling is lower than the self-sustainable start speed, the motor generator 2 needs to increase the engine rotational speed Ne to the self-sustainable start speed when the engine is restarted. That is, when the engine is restarted, the first clutch 51 is in a half-clutch state, and the difference between the maximum torque and the upper limit value of the motor torque (hereinafter referred to as “engine starting torque”) is input to the engine 1 by the motor generator 2. Because there is.

  FIG. 10 is a flowchart illustrating HEV travel mode transition processing.

  In step S61, the controller 7 reads the engine rotation speed Ne and the motor rotation speed Nm.

  In step S62, the controller 7 determines whether an engine restarting flag, which will be described later, is set to 0. If the engine restart flag is set to 0, the controller 7 performs the process of step S63. On the other hand, if the engine restarting flag is set to 1, the process of step S65 is performed. The engine restarting flag is set to 0 when the hybrid vehicle 100 is started.

  In step S63, the controller 7 determines whether or not the engine rotation speed Ne is equal to or higher than the self-startable speed. If the engine speed Ne is equal to or higher than the self-startable speed, the controller 7 performs the process of step S64. On the other hand, if the engine speed Ne is less than the self-startable speed, the process of step S70 is performed.

  In step S64, the controller 7 does not perform cranking by the motor generator 2, performs fuel injection and ignition on the engine 1 that is idling, and starts the engine 1 independently.

  In step S65, the controller 7 determines whether the engine rotation speed Ne has increased to the motor rotation speed Nm and the engine rotation speed Ne and the motor rotation speed Nm have become equal. If the engine rotational speed Ne has not yet increased to the motor rotational speed Nm and the engine rotational speed Ne and the motor rotational speed Nm are not equal, the controller 7 performs the process of step S66. On the other hand, if the engine rotational speed Ne and the motor rotational speed Nm are equal, the process of step S67 is performed.

  In step S66, the controller 7 sets the engine restarting flag to 1. The engine restarting flag is set to 1 until the engine rotational speed Ne and the motor rotational speed Nm are equal when the engine 1 is idling and fuel is injected and ignited to start the engine 1 independently. Flag to be

  In step S67, the controller 7 sets the engine restarting flag to 0.

  In step S <b> 68, the controller 7 engages the first clutch 51. As described above, when the engine rotation speed Ne and the motor rotation speed Nm are equal, the first clutch 51 is engaged to suppress a shock at the time of engagement of the first clutch.

  In step S69, the controller 7 sets the travel mode to the HEV travel mode. After setting the travel mode to the HEV travel mode, the controller 7 opens the on-off valve 65 and engages the electromagnetic clutch 664 to rotate the crankshaft 13 in conjunction with the rotation of the turbine 662. The power of the hybrid vehicle 100 is assisted.

  In step S <b> 70, the controller 7 increases the motor torque to the maximum motor torque, sets the first clutch 51 in a half-clutch state, cranks the engine 1 with the motor generator 2, and restarts the engine 1.

  FIG. 11 is a time chart showing the control operation of the hybrid vehicle 100 according to the present embodiment. In order to facilitate understanding of the invention, the operation according to the present embodiment is indicated by a thin solid line, the operation according to the conventional example is indicated by a broken line, and the common operation is indicated by a thick solid line.

  When the accelerator pedal is returned at time t1, the target drive torque is reduced to a torque that allows the vehicle to travel with only the motor torque in accordance with a decrease in the accelerator operation amount.

  From time t1 to time t2, the engine 1 torque and the motor torque are reduced so that the drive torque becomes the target drive torque.

  When the motor torque reaches the target drive torque at time t2, the first clutch 51 is released, the fuel injection is stopped, the self-sustained operation of the engine 1 is stopped, and EV traveling that travels using only the motor torque is started. Then, it is determined whether or not the idling operation of the engine 1 is to be performed by comparing the expander torque Tran and the friction torque Tfri.

  Here, since the expander torque Tran is larger than the friction torque Tfri, the open / close valve 65 is opened and the electromagnetic clutch 664 is engaged in order to perform the idling operation of the engine 1. As a result, the refrigerant circulates through the refrigerant passage 61 and the turbine 662 rotates, and the rotation shaft 661 and the expander pulley 663 provided at the other end of the rotation shaft 661 rotate in conjunction with the rotation of the turbine 662. As a result, the crankshaft 13 is rotated via the belt, and the idling operation of the engine 1 is performed.

  When the accelerator pedal is depressed at time t3, the target drive torque increases to the maximum motor torque as the accelerator operation amount increases.

  Here, conventionally, since the engine 1 is cranked and restarted by the motor generator 2, the motor generator 2 can be driven only within the range of the limit torque. Therefore, at the time t3 when the target drive torque becomes the maximum motor torque larger than the limit torque, it is necessary to restart the engine 1 in order to shift to HEV traveling.

  On the other hand, in the present embodiment, by performing idling operation of the engine 1 during EV traveling, fuel injection is performed on the engine 1 during idling operation without performing cranking by the motor generator 2. The engine 1 can be started independently. Therefore, the motor generator 2 can be driven with the maximum motor torque, and EV travel can be performed after time t3.

  When the accelerator pedal is further depressed at time t4 and the accelerator operation amount further increases and the target drive torque becomes larger than the maximum motor torque, the process of shifting to HEV travel is performed. Here, since the engine rotation speed Ne during the idling operation is equal to or higher than the self-startable speed, fuel injection and ignition are performed on the engine 1 during the idling operation, and the engine 1 is autonomously started.

  When the engine rotational speed Ne and the motor rotational speed Nm become equal at time t5, the first clutch 51 is engaged.

  As described above, in the case of the present embodiment, the EV travel can be performed from the time t3 to the time t4 when the target drive torque is the maximum torque, so that the fuel efficiency can be improved.

  According to the present embodiment described above, the waste heat of the engine 1 is regenerated as power by the Rankine cycle system 6, and the idling operation of the engine 1 is performed with the regenerated power during EV traveling.

  Thus, when the engine is restarted when shifting from EV traveling to HEV traveling, if the engine rotation speed Ne during the idling operation is equal to or higher than the self-sustainable start speed, fuel injection to the engine 1 during the idling operation is performed. And by performing ignition, the engine 1 can be started independently. That is, the engine 1 can be started independently without performing cranking by the motor generator 2.

  Therefore, it is not necessary to drive the motor generator 2 while leaving a surplus power for the starting torque during EV travel. In other words, if the engine speed Ne during idling is equal to or higher than the self-startable speed, the upper limit value of the motor torque can be set to the maximum motor torque, and the output of the motor generator 2 can be increased up to the maximum motor torque during EV traveling. Can be increased. Therefore, since the ratio of EV traveling during traveling can be increased, fuel efficiency can be improved.

  On the other hand, if the engine rotational speed Ne during the idling operation is less than the self-startable speed, the upper limit value of the motor torque is set to decrease as the engine rotational speed Ne decreases.

  When the engine is restarted when shifting from EV traveling to HEV traveling, if the idling engine rotational speed Ne is less than the self-sustainable starting speed, the engine start according to the engine rotational speed Ne at the engine restart is performed. The partial torque is input to the engine 1 by the motor generator 2, and the engine 1 is restarted by assisting the cranking by the motor generator 2.

  At this time, the engine starting torque necessary for raising the crankshaft 13 already rotating at a speed lower than the self-startable speed to the self-startable speed is necessary for rotating the crankshaft 13 from a stationary state. Less than the starting torque.

  Therefore, the upper limit value of the motor torque (maximum motor torque-engine starting torque) set when the engine rotation speed Ne during idling is less than the self-sustainable start speed is the same as the conventional limit torque (maximum motor torque-start-up). Torque). Therefore, since the ratio of EV traveling during traveling can be increased, fuel efficiency can be further improved.

  Further, according to the present embodiment, when the friction torque Tfri is larger than the expander torque Tran, the open / close valve 65 of the Rankine cycle system 6 is closed and the electromagnetic clutch 664 is released so that the engine 1 is not idling. did.

  This is because if the friction torque Tfri is larger than the expander torque Tran, it is difficult to maintain the engine rotational speed Ne at a speed that allows the engine to start independently even when the engine 1 is idling. Therefore, in such a case, the regenerative power is accumulated by closing the on-off valve 65 of the Rankine cycle system 6 and maintaining the pressure in the second refrigerant passage 61, and during HEV running after the engine 1 is restarted. This is because it is more efficient to assist the driving force with this regenerative power.

  By doing so, the engine torque can be suppressed by the amount of the regenerative power during HEV traveling, so that fuel efficiency can be improved.

  Note that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  For example, the first clutch 51 may be replaced with a planetary gear mechanism.

  The second clutch 53 of the hybrid vehicle 100 may be separately provided between the motor generator 2 and the automatic transmission 42 or may be separately provided behind the automatic transmission 52. Further, the present invention is not limited to this, and the second clutch 53 may be provided between the motor generator 2 and the drive wheel 57.

1 Engine 2 Motor generator (motor)
6 Rankine cycle system (waste heat regeneration device)
11 Belt (regenerative power transmission mechanism)
12 Crank pulley (regenerative power transmission mechanism)
51 1st clutch (transmission amount adjuster)
63 Heat exchanger (evaporator)
65 On-off valve (flow adjustment valve)
66 expander 100 hybrid vehicle 663 expander pulley (regenerative power transmission mechanism)
664 Electromagnetic clutch (clutch)
S31 Regenerative power estimating means S32 Friction force estimating means S35 Clutch control means S37 Flow rate adjusting valve control means, clutch control prohibiting means S52 Motor output setting means S63 Engine starting means

Claims (9)

A control device for a hybrid vehicle including an engine and a motor as a power source,
A waste heat regeneration device that regenerates waste heat of the engine as regenerative power;
A regenerative power transmission mechanism that transmits regenerative power regenerated by the waste heat regenerative device to the output shaft of the engine during EV travel that travels using only the motor as a power source;
A control apparatus for a hybrid vehicle, comprising: A clutch provided in the power transmission path of the regenerative power;
Clutch control means for connecting the clutch during the EV running;
The control apparatus of the hybrid vehicle of Claim 1 characterized by the above-mentioned. Regenerative power estimation means for estimating regenerative power regenerated by the waste heat regenerator,
Frictional force estimating means for estimating the frictional force generated at the sliding portion of the engine;
Clutch control prohibiting means for prohibiting the clutch control when the frictional force is greater than the regenerative power and keeping the clutch released during the EV travel;
The hybrid vehicle control device according to claim 2, further comprising: The waste heat recovery device is
A heat exchanger that exchanges heat between the waste heat of the engine and a refrigerant; an expander that is driven by the refrigerant that exchanges heat in the heat exchanger and generates regenerative power;
A flow rate adjusting valve for adjusting the flow rate of the refrigerant flowing into the expander;
Including
Regenerative power estimating means for estimating the regenerative power of the expander based on the pressure of the refrigerant flowing into the expander and the rotational speed of the expander;
Friction force estimating means for estimating the friction force generated at the sliding portion of the engine according to the engine water temperature;
When the frictional force is larger than the regenerative power of the expander, a flow rate adjustment valve control means for closing the flow rate adjustment valve during the EV travel;
Clutch control prohibiting means for prohibiting the clutch control when the frictional force is larger than the regenerative power of the expander and keeping the clutch released during the EV travel;
The hybrid vehicle control device according to claim 2, further comprising: Motor output setting means for setting an output upper limit value of the motor based on the rotational speed of the output shaft of the engine during the EV running;
The hybrid vehicle control device according to any one of claims 1 to 4, wherein the control device is a hybrid vehicle control device. The motor output setting means includes
When the rotational speed of the output shaft of the engine during the EV traveling is equal to or higher than a predetermined rotational speed at which the engine can be started independently, the output upper limit value of the motor is set to the maximum output value of the motor. ,
The control apparatus for a hybrid vehicle according to claim 5. The motor output setting means includes
When the rotational speed of the output shaft of the engine during the EV traveling is less than a predetermined rotational speed at which the engine can be started independently, the lower the rotational speed of the output shaft of the engine, the lower the output upper limit of the motor Set the value to be smaller,
The hybrid vehicle control device according to claim 5 or 6, wherein the control device is a hybrid vehicle control device. A transmission amount adjuster that is provided in a power transmission path between the engine and the motor and adjusts the transmission amount of power;
Engine starting means for restarting the engine in a state in which the transmission amount of power by the transmission amount adjuster is controlled to zero when shifting from the EV traveling to HEV traveling that includes the engine as a power source. When,
The hybrid vehicle control device according to any one of claims 1 to 7, further comprising: The engine starting means is
When the rotational speed of the output shaft of the engine during EV traveling is equal to or higher than a predetermined rotational speed at which the engine can be started independently, the transmission amount of power by the transmission amount adjuster is controlled to zero To restart the engine,
The control apparatus for a hybrid vehicle according to claim 8.

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