JP2009173124A - Hybrid vehicle and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain overheating of heat exchange medium of an exhaust heat recovery device, the overheating generated when a vehicle is stopped by stopping operation of an internal combustion engine, immediately after the internal combustion engine is driven at a high load. <P>SOLUTION: When the vehicle is stopped by stopping the engine, in a state where it is determined that cooling water has become overheated, a throttle valve is fully open, and at the same time, engine is motored at idle rotation speed by a motor MG1 (Steps S230 through S290). As a result of this, a supply of relatively low temperature air to an exhaust heat recovery unit can restrain the cooling water flowing into a heat exchange part of the exhaust heat recovery unit from becoming an overheated state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle and a control method thereof.

  Conventionally, as this type of hybrid vehicle, one having an exhaust heat recovery device that recovers thermal energy of exhaust gas in an exhaust system of an engine has been proposed (see, for example, Patent Document 1). In this hybrid vehicle, the heating performance and fuel efficiency are improved by collecting the heat of the exhaust gas when heating is requested or when the engine is warmed up to quickly warm the engine coolant. .

  Further, when the engine cooling water temperature exceeds a preset temperature when the condition for stopping the operation of the engine that is idling is satisfied, the engine is cut in fuel depending on the remaining capacity SOC of the main battery. Have also been proposed (for example, see Patent Document 2). In this hybrid vehicle, the cooling of the engine is ensured by continuing the circulation of the cooling water of the engine by such control.

JP 2006-291906 A JP 2001-182580 A

  However, in a hybrid vehicle having an exhaust heat recovery device such as the former hybrid vehicle described above, when the engine is stopped and stopped immediately after the engine is operated at a high load, the exhaust heat recovery device becomes hot and the exhaust heat recovery device The heat exchange medium in the vessel may overheat. In this case, if the temperature of the cooling water of the engine is increased, the engine may be motored or idled as in the latter hybrid vehicle described above, but the waste heat recovery device becomes hot. Can not cope.

  The hybrid vehicle of the present invention and the control method thereof suppress the overheating of the heat exchange medium of the exhaust heat recovery device that may occur when the internal combustion engine is stopped and stopped immediately after the internal combustion engine is operated at a high load. Main purpose.

  The hybrid vehicle of the present invention and its control method employ the following means in order to achieve the main object described above.

The hybrid vehicle of the present invention
An internal combustion engine that outputs driving power, a driving motor that outputs driving power, a motoring motor that motors the internal combustion engine, and an exhaust system of the internal combustion engine that is attached to the internal combustion engine. An exhaust heat recovery device that heats the cooling medium to be cooled using the heat of the exhaust, and a hybrid vehicle that travels with intermittent operation of the internal combustion engine,
An overheat state determining means for determining that the heat exchange medium of the exhaust heat recovery device is in an overheat state;
When the operation of the internal combustion engine is stopped and the vehicle is stopped or traveling at a low vehicle speed lower than a predetermined vehicle speed while the heat exchange medium is determined to be in an overheat state by the overheat state determination means, the heat exchange medium is The internal combustion engine and the motor for motoring so that the internal combustion engine is motored in a state where fuel supply to the internal combustion engine is stopped until at least a part of a predetermined condition including a condition for eliminating the overheating state of the engine is satisfied Control means for controlling
It is a summary to provide.

  In the hybrid vehicle of the present invention, when the heat exchange medium is overheated, when the operation of the internal combustion engine is stopped and the vehicle is stopped or traveling at a low vehicle speed lower than a predetermined vehicle speed, the overheat state of the heat exchange medium is eliminated. The internal combustion engine and the motor for motoring are controlled so that the internal combustion engine is motored in a state where the fuel supply to the internal combustion engine is stopped until at least a part of the predetermined condition including the conditions to be satisfied is satisfied. That is, by motoring the internal combustion engine with the fuel supply stopped, relatively low temperature air is supplied as exhaust to the exhaust heat recovery device. Thereby, the exhaust heat recovery device can be cooled, and the heat exchange medium of the exhaust heat recovery device can be prevented from being overheated.

  In the hybrid vehicle of the present invention, the control means may be means for controlling the internal combustion engine such that a throttle valve of the internal combustion engine is not less than a predetermined opening when the internal combustion engine is motored. In this way, the exhaust heat recovery device can be cooled more quickly by increasing the amount of air supplied to the exhaust heat recovery device.

  In the hybrid vehicle of the present invention, the condition for eliminating the overheated state of the heat exchange medium may be a condition for the heat exchange medium to be below a predetermined temperature.

  In the hybrid vehicle of the present invention, the predetermined condition may be a condition including a condition that a predetermined time has elapsed since the start of motoring of the internal combustion engine. In this way, since the motoring does not continue beyond the predetermined time, it is possible to suppress a significant decrease in the remaining capacity (SOC) of the power storage means.

  In the hybrid vehicle of the present invention, the heat exchange medium may be the cooling medium. That is, the present invention can be applied to an apparatus for heating a cooling medium using exhaust heat without using a heat exchange medium in an exhaust heat recovery apparatus.

  The hybrid vehicle of the present invention includes a circulation means for circulating the heat exchange medium, and the control means is a means for controlling the circulation means so that the heat exchange medium circulates during motoring of the internal combustion engine. It can also be. In this way, it is possible to prevent the heat exchange medium from being overheated even in a hybrid vehicle having circulation means that operates regardless of the power of the internal combustion engine.

The method for controlling a hybrid vehicle according to the present invention includes an internal combustion engine that outputs power for traveling, a motor for traveling that outputs power for traveling, a motor for motoring that motors the internal combustion engine, and the internal combustion engine. An exhaust heat recovery device that is attached to an exhaust system and heats a cooling medium that cools the internal combustion engine using heat of the exhaust, and is a control method for a hybrid vehicle that travels with intermittent operation of the internal combustion engine. There,
When the heat exchange medium of the exhaust heat recovery device is overheated, the operation of the internal combustion engine is stopped and the vehicle is stopped or traveling at a low vehicle speed lower than a predetermined vehicle speed. Controlling the internal combustion engine and the motoring motor so that the internal combustion engine is motored in a state where fuel supply to the internal combustion engine is stopped until at least part of a predetermined condition including the condition is satisfied,
This is the gist.

  In the hybrid vehicle control method of the present invention, when the heat exchange medium is overheated, when the operation of the internal combustion engine is stopped and the vehicle is stopped or traveling at a low vehicle speed less than a predetermined vehicle speed, the heat exchange medium is overheated. The internal combustion engine and the motor for motoring are controlled so that the internal combustion engine is motored in a state where the fuel supply to the internal combustion engine is stopped until at least a part of the predetermined condition including the condition for eliminating is satisfied. That is, by motoring the internal combustion engine with the fuel supply stopped, relatively low temperature air is supplied as exhaust to the exhaust heat recovery device. Thereby, the exhaust heat recovery device can be cooled, and the heat exchange medium of the exhaust heat recovery device can be prevented from being overheated.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. In the hybrid vehicle 20 of the embodiment, as shown in the figure, a carrier is connected to an engine 22 and a crankshaft 26 as an output shaft of the engine 22, and a drive is connected to drive wheels 38 a and 38 b via a differential gear 36. A planetary gear mechanism 30 having a ring gear connected to the shaft 32; a power-generating motor MG1 having a rotating shaft connected to the sun gear of the planetary gear mechanism 30; and a power-generating motor MG2 having a rotating shaft connected to the drive shaft 32; A cooling system 100 that cools the engine 22, an exhaust heat recovery unit 93 that recovers heat of the exhaust of the engine 22 and warms the cooling water of the engine 22 when the engine 22 is warmed up, and motors MG1 and MG2. Battery 50 that exchanges power via inverters 41 and 42, and engine electronics that control engine 22 A control unit (hereinafter referred to as engine ECU) 24, a motor electronic control unit (hereinafter referred to as motor ECU) 40 that controls driving of motors MG1 and MG2 and manages battery 50, and the entire hybrid vehicle 20 are controlled. And a hybrid electronic control unit (hereinafter referred to as hybrid ECU) 70.

  The engine 22 is configured as an internal combustion engine capable of outputting power using a hydrocarbon-based fuel such as gasoline or light oil, for example, and sucks air purified by an air cleaner 82 via a throttle valve 84, and the sucked air The mixture of gasoline and gasoline is exploded and burned in the fuel chamber, and the reciprocating motion of the piston pushed down by the energy is converted into the rotational motion of the crankshaft 26. Exhaust gas from the engine 22 is supplied to outside air through a purification device (three-way catalyst) 92 that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) and an exhaust heat recovery unit 93. Is discharged. The engine ECU 24 receives signals from various sensors that detect the operating state of the engine 22, for example, a crank position from a crank position sensor (not shown) that detects a crank angle of the crankshaft 26 of the engine 22 via an input port. Has been. The engine ECU 24 outputs various control signals for driving the engine 22, for example, a drive signal to the throttle motor 86 that adjusts the position of the throttle valve 84 through the output port. The engine ECU 24 is in communication with the hybrid ECU 70, controls the operation of the engine 22 by a control signal from the hybrid ECU 70, and outputs data related to the operating state of the engine 22 as necessary.

  The cooling system 100 cools the engine 22 by circulating cooling water through a cooling water flow path that includes the radiator 102 and the cooling water flow path of the engine 22 in the circulation flow path. The cooling system 100 includes a water pump 101 that circulates cooling water using the power of the engine 22, an electric cooling fan 106 that blows air to the radiator 102, and a water temperature sensor 104 that detects a water temperature Tw as the temperature of the cooling water. Is provided. The water temperature Tw from the water temperature sensor 104 is input to the engine ECU 24 through a signal line. Cooling fan 106 is driven by a drive signal from engine ECU 24 based on water temperature Tw.

  The exhaust heat recovery unit 93 includes a heat exchanging part 96 through which a part of the cooling water is circulated to exchange heat between the exhaust heat and the cooling water, and a heat exchanging part as an exhaust path passing through the exhaust heat recovery unit 93. It includes a flow path switching valve 97 that can switch between a path that circulates on the 96 side and a path that passes as it is. When the cooling water temperature Tw is low and there is a request for warming up, such as when the hybrid vehicle 20 is started, the exhaust heat recovery unit 93 closes the flow path switching valve 97 and exchanges heat from the exhaust from the engine 22. The cooling water is warmed by circulating to the part 96 side to promote warming up. When the warming up is finished, the flow path switching valve 97 is opened, and the exhaust from the engine 22 is sent to the heat exchanging part 96 side. By allowing the heat exchange unit 96 to pass through without being circulated, the heat exchange between the heat of the exhaust and the cooling water is hardly performed. The flow path switching valve 97 is switched between an open state and a closed state by the engine ECU 24 driving and controlling the actuator 98.

  Although not shown, the hybrid ECU 70 is configured as a microprocessor centered on a CPU. In addition to the CPU, a ROM that stores a processing program, a RAM that temporarily stores data, an input / output port and a communication port are provided. Prepare. The hybrid ECU 70 is input with various signals accompanying a driver's operation and a vehicle speed V from a vehicle speed sensor (not shown) via an input port. The hybrid ECU 70 is connected to the engine ECU 24 and the motor ECU 40 via a communication port, and exchanges various control signals and data with the engine ECU 24 and the motor ECU 40.

  Next, the operation of the hybrid vehicle 20 of the embodiment configured as described above, particularly the operation when the engine 22 is stopped and stopped in a state where it is determined that the cooling water is overheated will be described. For convenience of explanation, the process of determining whether the cooling water is overheated first will be described using the overheat state determination routine illustrated in FIG. 2, and then the engine 22 is stopped and stopped. The control of the engine 22 and the motors MG1, MG2 will be described using an engine stop time control routine illustrated in FIG. 2 is executed every predetermined time (for example, every several msec) by the engine ECU 24, and the engine stop time control routine of FIG. 3 is executed every predetermined time (for example, every several msec) by the hybrid ECU 70. Executed.

  When the overheat state determination routine of FIG. 2 is executed, the engine ECU 24 first executes a process of inputting the water temperature Tw from the water temperature sensor 104 (step S100), and compares the input water temperature Tw with a threshold Th ( In step S110), the temperature rise value obtained by subtracting the water temperature Tw input in this routine from the previous water temperature Tw is compared with the threshold value Tr (step S120). Here, the threshold value Th is set as a lower limit temperature at which the cooling water may be in an overheated state. For example, the temperature immediately before the overheated state such as 95 ° C., 100 ° C., or 105 ° C. is used. Can do. The threshold value Tr is set as a lower limit value of a temperature increase value per unit time that can be determined to be an overheated state when the water temperature Tw exceeds the threshold value Th, and is based on an experimental value of a time change rate of the water temperature Tw. Can be determined.

  When the input water temperature Tw is less than the threshold value Th, or when the water temperature Tw is equal to or higher than the threshold value Th but the temperature rise value of the water temperature Tw is less than the threshold value Tr, it is determined that the cooling water of the engine 22 is not overheated immediately. This routine ends.

  On the other hand, when the input water temperature Tw is equal to or higher than the threshold Th and the temperature rise value is equal to or higher than the threshold Tr, it is determined that the cooling water of the engine 22 is in an overheated state, and the value 1 is set in the overheated state flag F (Step S130). Exit the routine. Here, the overheat state flag F is set to a value 0 as an initial value by an initialization routine (not shown) in the embodiment, and after it is determined that the overheat state is set and a value 1 is set, the engine is stopped later. The value is reset to 0 when a predetermined condition is satisfied in the control routine. Based on such determination, it is possible to determine that the engine 22 is overheated using the coolant temperature Tw of the cooling water of the engine 22 and the temperature increase value thereof.

  Next, control of the engine 22 and the motors MG1, MG2 when the engine 22 is stopped and stopped will be described. When the engine stop control routine of FIG. 3 is executed, the CPU (not shown) of the hybrid ECU 70 first executes a process of inputting data necessary for control such as the water temperature Tw, the rotational speed Nm1 of the motor MG1, and the overheat state flag F. (Step S200). Here, as the water temperature Tw, the water temperature Tw from the water temperature sensor 104 is input from the engine ECU 24 by communication. Further, the rotational speed Nm1 of the motor MG1 is calculated from the rotational position of the rotor of the motor MG1 detected by a rotational position detection sensor (not shown) and is input from the motor ECU 40 by communication. The overheat state flag F is input from the engine ECU 24 by communication.

  Subsequently, the value of the overheat state flag F is checked (step S210). When the overheat state flag F is 0, that is, when it is determined in the overheat state determination routine of FIG. 2 that the cooling water of the engine 22 is not overheated and does not become overheated, the engine 22 is stopped. (Step S220), this routine is finished.

  When the overheat state flag F is 1, that is, when it is determined that the cooling water is overheated or overheated, the water temperature Tw is compared with the threshold value Tc (step S230), and the counter C is set to the threshold value C1. Compare (step S240). Here, the threshold value Tc is set as the upper limit value of the temperature at which it is determined that the overheating state of the cooling water has been eliminated. For example, the threshold value Tc is used when determining the overheating state such as 80 ° C, 85 ° C, 90 ° C. A value lower than the threshold Th can be used. The counter C counts the number of times steps S250 to S280, which will be described later, are executed, that is, measures the time during which these processes are executed. Used to limit what is continued.

  Now, considering that the engine 22 is stopped after the value 1 is set in the overheat flag F, the water temperature Tw is equal to or higher than the threshold value Tc and the counter C is lower than the threshold value C1. ) Based on the motoring rotational speed Nset calculated based on the idle rotational speed Nidle of the engine 22 and the gear ratio ρ of the planetary gear mechanism 30 and the rotational speed Nm1 of the motor MG1 as shown in FIG. The torque command Tm1 * of MG1 is calculated and set (step S250), and the torque command Tm1 * set as shown in the equation (3) is divided by the gear ratio ρ of the planetary gear mechanism 30 to obtain the torque command Tm2 of the motor MG2. * Is set (step S260). Here, the expression (1) is a mechanical relationship with respect to the rotating elements of the planetary gear mechanism 30 when the engine 22 is motored at an idle speed Nidle (for example, 800 rpm, 1000 rpm, etc.) when the vehicle is stopped. It is a formula. FIG. 4 shows an example of a collinear diagram showing the dynamic relationship between the rotational speed and torque in the rotating element of the planetary gear mechanism 30 when the hybrid vehicle 20 is stopped. In the figure, the left S-axis indicates the rotational speed of the sun gear, which is the rotational speed Nm1 of the motor MG1, the C-axis indicates the rotational speed of the carrier, which is the rotational speed Ne of the engine 22, and the R-axis indicates the rotational speed Nm2 of the motor MG2. Indicates the number of rotations of a ring gear. Equation (1) can be easily derived by using this alignment chart. Note that the two thick arrows on the R axis indicate the torque that the torque Tm1 output from the motor MG1 acts on the ring gear and the torque that the Tm2 output from the motor MG2 acts on the ring gear. Further, Expression (2) is a relational expression in feedback control for rotating the motor MG1 at the motoring rotation speed Nset, and is a gain of the “k1” proportional term in the second term on the right side in Expression (2). , “K2” integral term gain of the third term on the right side. Moreover, Formula (3) can be easily derived from the alignment chart of FIG.

Nset = Nidle ・ (1 + ρ) / ρ (1)
Tm1 * = previous Tm1 * + k1 (Nset−Nm1) + k2∫ (Nest−Nm1) dt (2)
Tm2 * = Tm1 * / ρ (3)

  When the torque commands Tm1 * and Tm2 * for the motors MG1 and MG2 are set in this way, the set torque commands Tm1 * and Tm2 * for the motors MG1 and MG2 are transmitted to the motor ECU 40 (step S270), and the throttle valve 84 is fully opened. Is transmitted to the engine ECU 24 (step S280), the counter C is incremented by 1 (step S290), and the engine stop time control routine is terminated. Receiving the torque commands Tm1 * and Tm2 *, the motor ECU 40 controls the switching elements of the inverters 41 and 42 so that the motor MG1 is driven by the torque command Tm1 * and the motor MG2 is driven by the torque command Tm2 *. . The engine ECU 24 that has received the throttle valve full open command maintains the state where the control such as fuel injection is stopped and controls the throttle motor 86 so that the throttle valve 84 is fully opened. In this way, by motoring the engine 22 in a state where the fuel supply is stopped, relatively low-temperature air is supplied to the exhaust heat recovery unit 93, and the cooling water flowing to the heat exchange unit 96 of the exhaust heat recovery unit 93 is supplied. Cool down. As a result, the cooling water is overheated, and the exhaust heat recovery unit 93 can be prevented from overheating.

  When it is determined in step S230 that the water temperature Tw is lower than the threshold value Tc while the motoring of the engine 22 is being continued, it is determined that the cooling water is overheated or overheated. Then, a motoring stop instruction for stopping the motoring of the engine 22 is transmitted to the engine ECU 24 and the motor ECU 40 (step S300), and a flag reset instruction for resetting the overheat state flag F to the value 0 is transmitted to the engine ECU 24 (step S300). (S310), the counter C is reset to 0 (step S320), and the engine stop time control routine is terminated. Receiving the motoring stop instruction, the motor ECU 40 performs control to stop the motoring such as preventing torque from being generated in the motors MG1 and MG2. The engine ECU 24 that has received the motoring stop instruction and the flag reset instruction executes a process for controlling the throttle motor 86 so that the throttle valve 84 returns to a predetermined position, and a process for resetting the overheat state flag F to a value of 0. Execute.

  Further, if the water temperature Tw does not reach below the threshold value Tc by the motoring of the engine 22 and the counter C exceeds the threshold value C1, it is determined that excessive motoring should be stopped, and the motoring for stopping the motoring of the engine 22 is performed. A stop instruction is transmitted to the engine ECU 24 and the motor ECU 40 (step S300), a flag reset instruction for resetting the overheat state flag F to the value 0 is transmitted to the engine ECU 24 (step S310), and the counter C is reset to the value 0. (Step S320), the engine stop time control routine is terminated. Thereby, motoring the engine 22 for a long time can be avoided.

  According to the hybrid vehicle 20 of the embodiment described above, when the engine 22 is stopped and stopped in a state where it is determined that the cooling water is overheated or overheated, the fuel supply to the engine 22 is stopped. Since the engine 22 is motored by the motor MG1, the cooling water flowing through the heat exchanging unit 96 of the exhaust heat recovery unit 93 is prevented from being overheated by supplying relatively low temperature air to the exhaust heat recovery unit 93. can do. Further, when the engine 22 is motored, the throttle valve 84 is fully opened to increase the amount of air supplied to the exhaust heat recovery unit 93. Therefore, the exhaust heat recovery unit 93 is cooled more effectively and the cooling water is overheated. Can be suppressed. In addition, since the motoring is not continued beyond the predetermined time, it is possible to suppress the remaining capacity (SOC) of the battery 50 from being significantly reduced. Further, when it is determined whether the cooling water is overheated or overheated, the cooling water temperature Tw of the engine 22 and the temperature increase value thereof are used. Therefore, it is possible to more accurately determine whether the cooling water is overheated. it can.

  In the hybrid vehicle 20 of the embodiment, when the engine 22 is motored, the throttle valve 84 is fully opened. However, the opening degree is slightly smaller than the full opening, or when the throttle valve 84 is stopped when the engine is stopped. The state may be maintained, or may be opened to a predetermined intermediate opening.

  In the hybrid vehicle 20 of the embodiment, the engine 22 is motored at the idle speed Nidle, but is motored at a predetermined speed such as 1000 rpm, 1100 rpm, and 1200 rpm, which is different from the idle speed Nidle. It may be a thing.

  In the hybrid vehicle 20 of the embodiment, when the operation of the engine 22 is stopped and the vehicle stops, the engine stop time control routine is executed. However, the operation of the engine 22 is stopped and only the power from the motor MG2 is used. The same control can be performed when the vehicle is traveling at a low vehicle speed (for example, 5 km / h). In this case, the motors MG1 and MG2 may be controlled so that the power required for the drive shaft 32 is output to the drive shaft 32 and the engine 22 is rotated at the idle speed Nidle.

  In the hybrid vehicle 20 of the embodiment, the motoring of the engine 22 is not continued for a predetermined time or more using the counter C and the threshold value C1, but such a time limit may not be used. Further, when the remaining capacity (SOC) of the battery 50 is reduced below a predetermined value, the motoring of the engine 22 may not be continued.

  In the hybrid vehicle 20 of the embodiment, the temperature is raised using the heat of the exhaust gas by circulating a part of the cooling water to the heat exchange unit 96 of the exhaust heat recovery unit 93. The heat exchange medium different from water circulates and includes a heat exchange device capable of exchanging heat between the cooling water and the heat exchange medium, and the heat exchange medium and the heat exchange unit 96 of the exhaust heat recovery unit 93 are combined with the heat exchange device. It is good also as what circulates between. In this case, the cooling water is heated using the heat of the exhaust through the heat exchange medium.

  In the hybrid vehicle 20 of the embodiment, the water temperature Tw from the water temperature sensor 104 is used to determine the overheated state of the cooling water or to control when the engine is stopped, but the water temperature such as the temperature of the exhaust heat recovery unit 93 is used. The determination and control may be performed without using Tw.

  In the hybrid vehicle 20 of the embodiment, the water pump 101 that operates with the power of the engine 22 is used. However, an electric water pump that operates with electric power may be used. In this case, the electric water pump may be operated when the engine 22 is motored in the engine stop time control routine of FIG.

  In the hybrid vehicle 20 of the embodiment, the power of the motor MG2 is output to the drive shaft 32. However, as illustrated in the hybrid vehicle 120 of the modified example of FIG. 5, the drive shaft 32 is connected to the power of the motor MG2. Further, it may be connected to an axle (an axle connected to the wheels 39a and 39b in FIG. 5) different from an axle (an axle to which the drive wheels 38a and 38b are connected).

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 corresponds to an “internal combustion engine”, the motor MG2 corresponds to a “traveling motor”, the motor MG1 corresponds to a “motoring motor”, and the exhaust heat recovery unit 93 corresponds to “exhaust heat recovery”. The engine ECU 24 that executes the process of the overheat state determination routine of FIG. 2 that sets the overheat state flag F to the value 1 based on the coolant temperature Tw of the cooling water of the engine 22 and the temperature rise value thereof corresponds to the “device”. When the engine 22 is stopped and stopped in a state where it is determined that the cooling water is overheated, the engine 22 is idle until the water temperature Tw becomes lower than the threshold value Tc or a predetermined time elapses. The engine stop of FIG. 3 is set and transmitted to the motor ECU 40 by setting torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 so as to perform motoring at the rotational speed Nidle The engine ECU 24 that controls the engine 22 and the throttle motor 86 of the engine 22 based on the commands from the hybrid ECU 70 and the hybrid ECU 70 that execute the processing of steps S230 to S290 of the hour control routine, and the motor based on the torque commands Tm1 * and Tm2 * The motor ECU 40 that performs switching control of the inverters 41 and 42 of the MG1 and MG2 corresponds to “control means”.

  The “internal combustion engine” is not limited to an internal combustion engine that outputs power using a hydrocarbon fuel such as gasoline or light oil, and may be any type of internal combustion engine such as a hydrogen engine. The “traveling motor” may be any type of motor that outputs traveling power, such as a synchronous generator motor or an induction motor. The “motoring motor” is not limited to the motor MG1 connected to the engine 22 via the planetary gear mechanism 30, and any motoring motor for an internal combustion engine such as a starter motor may be used. . The “exhaust heat recovery device” is not limited to one that raises the temperature using the heat of the exhaust gas by circulating a part of the cooling water to the heat exchange unit 96 of the exhaust heat recovery unit 93. And a heat exchange device that is capable of exchanging heat between the cooling water and the heat exchange medium, and a heat exchange unit of the exhaust heat recovery unit 93. A cooling medium that is attached to the exhaust system of the internal combustion engine and cools the internal combustion engine, such as a system that circulates between the heat exchanger 96 and the heat exchange device to raise the temperature of the cooling water using the heat of the exhaust through the heat exchange medium. Any material can be used as long as it is heated using the heat of exhaust gas. As the “overheating state determination means”, the cooling water flowing through the exhaust heat recovery unit is brought into an overheating state by comparing the temperature rise values of the cooling water temperature Tw and the water temperature Tw of the engine 22 with the threshold values Th and Tr, respectively. It is not limited to what is determined to be, and any may be used as long as it is determined that the heat exchange medium of the exhaust heat recovery apparatus is overheated. The “control means” is not limited to the combination of the hybrid ECU 70, the engine ECU 24, and the motor ECU 40, and may be configured by a single electronic control unit. Further, as the “control means”, fuel is supplied until the water temperature Tw becomes lower than the threshold value Tc or a predetermined time has elapsed when the engine 22 is stopped and stopped in a state where it is determined that the cooling water is overheated. Is not limited to controlling the engine 22 and the motors MG1 and MG2 so that the engine 22 is motored at the idle speed Nidle, but only the power from the motor MG2 is stopped by stopping the operation of the engine 22. When the vehicle is traveling at a speed lower than a predetermined low vehicle speed, the fuel supply is stopped until the water temperature Tw becomes lower than the threshold value Tc or a predetermined time elapses so that the engine 22 is motored at the idle speed Nidle. When the engine 22 is stopped and stopped in a state where it is determined that the motors MG1 and MG2 are controlled or the cooling water is overheated. The engine 22 and the motors MG1 and MG2 are controlled so that the engine 22 is motored at the idle speed Nidle until the water temperature Tw becomes less than the threshold value Tc without using the motoring time limit. When it is determined that the cooling water is overheated and the engine 22 is stopped and stopped, the fuel supply is stopped until the water temperature Tw becomes lower than the threshold value Tc or a predetermined time elapses, and the engine 22 is idle. Internal combustion with the heat exchange medium determined to be in an overheated state by the overheat state determining means, such as one that controls the engine 22 and the motors MG1 and MG2 to be motored at a predetermined number of rotations different from the rotation number Nidle. When the engine operation is stopped and the vehicle is stopped or traveling at a low vehicle speed lower than the predetermined vehicle speed, the overheat state of the heat exchange medium is resolved. As long as it controls the internal combustion engine and the motor for motoring so that the internal combustion engine is motored in a state where the fuel supply to the internal combustion engine is stopped until at least part of the predetermined condition including the condition is satisfied It doesn't matter. The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. It is an example for specifically explaining the best mode for doing so, and does not limit the elements of the invention described in the column of means for solving the problem. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

  The present invention can be used in the vehicle manufacturing industry.

1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20. FIG. It is a flowchart which shows an example of the overheat state determination routine performed by engine ECU24 of an Example. It is a flowchart which shows an example of the control routine at the time of an engine stop performed by hybrid ECU70 of an Example. FIG. 3 is an explanatory diagram showing an example of a collinear diagram showing a dynamic relationship between the number of rotations and torque in a rotating element of the planetary gear mechanism 30 when the hybrid vehicle 20 is stopped. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification.

Explanation of symbols

  20, 120 Hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 30 planetary gear mechanism, 32 drive shaft, 36 differential gear, 38a, 38b drive wheel, 39a, 39b wheel, 40 motor Electronic control unit (motor ECU), 41, 42 inverter, 50 battery, 54 power line, 70 hybrid electronic control unit (hybrid ECU), 82 air cleaner, 84 throttle valve, 86 throttle motor, 92 purification device (three-way catalyst) ), 93 Exhaust heat recovery unit, 96 Heat exchange unit, 97 Flow path switching valve, 98 Actuator, 100 Cooling system, 101 Water pump, 102 Radiator, 104 Water temperature sensor, 106 Cooling fan MG1, MG2 motor.

Claims (7)

An internal combustion engine that outputs driving power, a driving motor that outputs driving power, a motoring motor that motors the internal combustion engine, and an exhaust system of the internal combustion engine that is attached to the internal combustion engine. An exhaust heat recovery device that heats the cooling medium to be cooled using the heat of the exhaust, and a hybrid vehicle that travels with intermittent operation of the internal combustion engine,
An overheat state determining means for determining that the heat exchange medium of the exhaust heat recovery device is in an overheat state;
When the operation of the internal combustion engine is stopped and the vehicle is stopped or traveling at a low vehicle speed lower than a predetermined vehicle speed while the heat exchange medium is determined to be in an overheat state by the overheat state determination means, the heat exchange medium is The internal combustion engine and the motor for motoring so that the internal combustion engine is motored in a state where fuel supply to the internal combustion engine is stopped until at least a part of a predetermined condition including a condition for eliminating the overheating state of the engine is satisfied Control means for controlling
A hybrid car with   2. The hybrid vehicle according to claim 1, wherein the control means is means for controlling the internal combustion engine so that a throttle valve of the internal combustion engine is not less than a predetermined opening degree when the internal combustion engine is motored.   The hybrid vehicle according to claim 1, wherein the condition for eliminating the overheated state of the heat exchange medium is a condition for the heat exchange medium to be less than a predetermined temperature.   The hybrid vehicle according to any one of claims 1 to 3, wherein the predetermined condition is a condition including a condition in which a predetermined time has elapsed since the start of motoring of the internal combustion engine.   The hybrid vehicle according to any one of claims 1 to 4, wherein the heat exchange medium is the cooling medium. A hybrid vehicle according to any one of claims 1 to 5,
A circulation means for circulating the heat exchange medium;
The control means is means for controlling the circulation means so that the heat exchange medium circulates during motoring of the internal combustion engine.
Hybrid car. An internal combustion engine that outputs driving power, a driving motor that outputs driving power, a motoring motor that motors the internal combustion engine, and an exhaust system of the internal combustion engine that is attached to the internal combustion engine. An exhaust heat recovery device for heating a cooling medium to be cooled using heat of exhaust gas, and a control method for a hybrid vehicle that travels with intermittent operation of the internal combustion engine,
When the heat exchange medium of the exhaust heat recovery device is overheated, the operation of the internal combustion engine is stopped and the vehicle is stopped or traveling at a low vehicle speed lower than a predetermined vehicle speed. Controlling the internal combustion engine and the motoring motor so that the internal combustion engine is motored in a state where fuel supply to the internal combustion engine is stopped until at least part of a predetermined condition including the condition is satisfied,
A control method for a hybrid vehicle.

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