Hybrid vehicle

Abstract

To suppress a situation where the towable weight of a vehicle decreases relatively greatly and affects the drivability during travel in a towing mode.SOLUTION: A hybrid vehicle comprises: an engine and a motor for driving; an electric storage device for exchanging electric power with the motor; and a control device for controlling the engine and the motor so as to travel with engine operation in the towing mode. When the towing mode is instructed, the control device permits the towing mode if a power storage ratio of the electric storage device is higher than a threshold value, and prohibits the towing mode if the power storage ratio is equal to or lower than the threshold value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to hybrid vehicles. [Background technology]

[0002] In a conventional hybrid vehicle equipped with an engine and motor for driving and an electricity storage device that exchanges power with the motor, it has been proposed to prohibit intermittent operation of the engine and operate the engine continuously when in a towing mode in which the vehicle is towing a towed vehicle (see, for example, Patent Document 1). In this hybrid vehicle, this control makes it easier to ensure sufficient driving force when in towing mode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-112447 Summary of the Invention [Problem to be solved by the invention]

[0004] In the hybrid vehicle described above, when the vehicle is traveling in towing mode, the accelerator operation amount increases, which increases the power required for traveling, and the output from the power storage device tends to increase to cover the required power, which tends to reduce the power storage rate of the power storage device. If the power storage rate of the power storage device decreases sufficiently while the vehicle is traveling in towing mode, the motor output is limited to a relatively large extent to protect the power storage device, which significantly reduces the vehicle's towing capacity and may affect driving performance.

[0005] The hybrid vehicle of the present disclosure has a primary objective of suppressing a relatively large decrease in the towing capacity of the vehicle while traveling in towing mode, which would affect driving performance. [Means for solving the problem]

[0006] The hybrid vehicle of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] [1] The hybrid vehicle disclosed herein is A hybrid vehicle including an engine and a motor for running, an electricity storage device that exchanges electric power with the motor, and a control device that controls the engine and the motor so that the vehicle runs with the engine operating in a towing mode, When the towing mode is instructed, the control device permits the towing mode if a power storage rate of the power storage device is higher than a threshold value, and prohibits the towing mode if the power storage rate is equal to or lower than the threshold value. The gist of this is as follows.

[0008] In the hybrid vehicle disclosed herein, when a towing mode command is issued, the towing mode is permitted if the power storage rate of the power storage device is higher than a threshold, and the towing mode is prohibited if the power storage rate is equal to or lower than the threshold. This prevents the power storage rate of the power storage device from decreasing sufficiently while the vehicle is traveling in the towing mode, resulting in a relatively large decrease in the vehicle's towing capacity and an impact on driving performance.

[0009] [2] The hybrid vehicle described above (the hybrid vehicle described in [1]) may further include a notification device that notifies the driver of information, and the control device may control the notification device to notify prohibition-related information related to the prohibition of the towing mode when the towing mode is prohibited. Here, the prohibition-related information may be information that the towing mode has been prohibited, information that the towing mode has been prohibited because the power storage rate is equal to or less than a threshold, or information that a mode other than the towing mode (for example, a normal mode in which the vehicle travels with intermittent engine operation) will be maintained.

[0010] [3] The hybrid vehicle (the hybrid vehicle described in [1] or [2]) may further include a towing mode switch for indicating the towing mode, and the control device may determine that the towing mode has been indicated when the towing mode switch is operated by a user. Here, the towing mode switch may be configured as a hardware switch or a software switch displayed on a display unit or the like.

[0011] [4] In the above-mentioned hybrid vehicle (the hybrid vehicle described in [1] or [2]), the control device may determine that the towing mode has been instructed when the vehicle and the towed object are connected.

[0012] [5] In the above-mentioned hybrid vehicle (the hybrid vehicle described in [1] or [2]), the control device may determine that the towing mode has been instructed when the vehicle load exceeds a predetermined load.

[0013] [6] In the hybrid vehicle described in any one of [1] to [5], the control device may set the threshold value so that the higher the altitude of the current location of the vehicle and / or the planned driving route, the higher the threshold value. The altitude of the planned driving route may be the average altitude of each point on the planned driving route, or may be the maximum altitude of each point on the planned driving route.

[0014] [7] In the hybrid vehicle described in any one of [1] to [6], the control device may set the threshold value so that the threshold value increases as the road surface gradient of the current location of the vehicle and / or the planned driving route increases on the uphill side. The road surface gradient of the planned driving route may be the average value of the road surface gradients at each point on the planned driving route, or may be the maximum value of the road surface gradients at each point.

[0015] [8] In the above-mentioned hybrid vehicle (the hybrid vehicle described in any one of [1] to [7]), the control device may set the threshold value to be higher when the vehicle is traveling with the engine stopped than when the vehicle is traveling with the engine running.

[0016] [9] In the above-mentioned hybrid vehicle (the hybrid vehicle described in any one of [1] to [8]), the control device may terminate the towing mode when the storage ratio reaches or is equal to a second threshold value that is lower than the threshold value while traveling in the towing mode.

[0017]

[10] The hybrid vehicle described in [9] may further include a notification device that notifies the driver of information, and the control device may control the notification device to notify the driver of termination of the towing mode when the towing mode is terminated because the power storage percentage has reached or is equal to the second threshold while the vehicle is traveling in the towing mode. Here, the termination-related information may be information that the towing mode has been terminated, information that the towing mode has been terminated because the power storage percentage has reached or is equal to or less than the second threshold, or information that the vehicle has transitioned to a mode other than the towing mode (for example, the normal mode described above). [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic configuration diagram of a hybrid vehicle according to an embodiment of the present disclosure. [Figure 2] 10 is a flowchart illustrating an example of a processing routine in a normal mode. [Figure 3] 10 is a flowchart showing an example of a processing routine in a towing mode. [Figure 4] 10 is a flowchart illustrating an example of a processing routine in a normal mode. [Figure 5] 10 is a flowchart illustrating an example of a processing routine in a normal mode. [Figure 6] 10 is a flowchart illustrating an example of a processing routine in a normal mode. [Figure 7] 10 is a flowchart illustrating an example of a processing routine in a normal mode. [Figure 8] 10 is a flowchart illustrating an example of a processing routine in a normal mode. [Figure 9] FIG. 10 is a schematic diagram of a hybrid vehicle according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram of a hybrid vehicle 20 according to an embodiment of the present disclosure. As shown in Fig. 1, the hybrid vehicle 20 according to the embodiment includes an engine 22, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery 50, a connector 56, a charger 58, a navigation device 60, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0020] The engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel. A crankshaft 23 of the engine 22 is connected to a carrier of a planetary gear 30. The operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as "engine ECU") 24.

[0021] The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The engine ECU 24 receives signals from various sensors via its input ports. For example, the engine ECU 24 receives a crank angle θcr from a crank position sensor 23a that detects the rotational position of the crankshaft 23. The engine ECU 24 outputs various control signals via its output ports. For example, the engine ECU 24 outputs control signals to intake valves, fuel injection valves, and spark plugs (none of which are shown). The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the crankshaft 23. The engine ECU 24 communicates with the HVECU 70.

[0022] The planetary gear 30 is configured as a single-pinion type planetary gear mechanism. The sun gear of the planetary gear 30 is connected to the rotor of the motor MG1. The ring gear of the planetary gear 30 is connected to a drive shaft 37 that is connected to drive wheels 39a, 39b via a differential gear 38. As described above, the carrier of the planetary gear 30 is connected to the crankshaft 23 of the engine 22.

[0023] The motors MG1 and MG2 are configured as, for example, synchronous generator motors. As described above, the rotor of the motor MG1 is connected to the sun gear of the planetary gear 30. The rotor of the motor MG2 is connected to the drive shaft 37. The inverters 41 and 42 are configured as inverter circuits having a plurality of switching elements. The inverters 41 and 42 are connected to a battery 50 via a drive power line 54. The motor electronic control unit (hereinafter referred to as "motor ECU") 40 controls the switching of the plurality of switching elements of the inverters 41 and 42, thereby rotating and driving the motors MG1 and MG2.

[0024] The motor ECU 40 includes a microcomputer, similar to the engine ECU 24. The motor ECU 40 receives signals from various sensors via input ports. For example, the motor ECU 40 receives rotational positions θm1 and θm2 from rotational position sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2. The motor ECU 40 outputs various control signals via output ports. For example, the motor ECU 40 outputs control signals to inverters 41 and 42. The motor ECU 40 calculates the electrical angles θe1 and θe2 and rotation speeds Nm1 and Nm2 of the motors MG1 and MG2 based on the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2. The motor ECU 40 communicates with the HVECU 70.

[0025] Battery 50 is configured as, for example, a lithium ion secondary battery or a nickel-metal hydride secondary battery. As described above, battery 50 is connected to inverters 41, 42 via drive power line 54. Battery 50 is managed by battery electronic control unit (hereinafter referred to as "battery ECU") 52.

[0026] The battery ECU 52 includes a microcomputer, similar to the engine ECU 24. The battery ECU 52 receives signals from various sensors via an input port. For example, the battery ECU 52 receives a voltage Vb from a voltage sensor 51v attached between the terminals of the battery 50, a current Ib from a current sensor 51i attached to the output terminal of the battery 50, and a temperature Tb from a temperature sensor 51t attached to the battery 50. The battery ECU 52 calculates the state of charge (SOC) of the battery 50 based on the integrated value of the current Ib of the battery 50. The battery ECU 52 communicates with the HVECU 70.

[0027] Connector 56 is configured to be connectable to an external AC power source such as a household power source or a commercial power source. The external power source is provided at home or at a charging point such as a charging station. Connector 56 is connected to drive power line 54 via charging power line 57. Charger 58 is provided on charging power line 57 and is configured to convert AC power from the external power source into DC power, further convert the voltage, and supply the DC power to battery 50 when connector 56 is connected to the external power source. Hereinafter, charging battery 50 by supplying power from an external power source to battery 50 via charging power line 57 and drive power line 54 will be referred to as "external charging."

[0028] The navigation device 60 includes a main body 61 with a built-in control unit, a GPS antenna 62, and a display 63. The control unit of the main body 61 has a microcomputer and a storage medium (e.g., a hard disk, an SSD, etc.). The storage medium stores map information and the like. The map information includes service information (e.g., tourist information, parking lots, etc.) and road information for each driving section (e.g., between traffic lights, between intersections, etc.). The road information includes distance information, road width information, number of lanes information, area information (urban area or suburban area), type information (general road or expressway), gradient information, legal speed limit, etc. The GPS antenna 62 receives information related to the current location of the vehicle. The display 63 is configured as a touch panel type display and displays various information such as map information, the current location of the vehicle, and the planned driving route from the current location of the vehicle to the destination, and also allows the user to input various instructions. When the user sets a destination by operating the display 63, the main body 61 sets a planned driving route from the current location of the vehicle to the destination based on map information, the current location of the vehicle, and the destination, and provides route guidance by displaying the set planned driving route on the display 63. The navigation device 60 communicates with the HVECU 70.

[0029] The HVECU 70 includes a microcomputer, similar to the engine ECU 24. The HVECU 70 receives signals from various sensors via input ports. For example, the HVECU 70 receives a signal from a power switch 80, a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81, an accelerator pedal opening Acc from an accelerator pedal position sensor 84 that detects the depression amount of an accelerator pedal 83, and a brake pedal position BP from a brake pedal position sensor 86 that detects the depression amount of a brake pedal 85. The HVECU 70 also receives a vehicle speed V from a vehicle speed sensor 87, a vehicle acceleration α from an acceleration sensor 88, a road gradient θrd (positive value on an uphill road and negative value on a downhill road) from a gradient sensor 89, and an altitude EL from an altitude sensor 90. The HVECU 70 also receives a signal from a towing mode switch 91 that indicates a towing mode for traveling while towing a towed object. Examples of towed objects include a car and a boat. The HVECU 70 outputs various control signals via output ports. For example, the HVECU 70 outputs a control signal to the charger 58, a control signal to a display unit 92 attached to the instrument panel, and a control signal to a speaker 93. As described above, the HVECU 70 communicates with the engine ECU 24, the motor ECU 40, the battery ECU 52, and the main body 61 of the navigation device 60.

[0030] The hybrid vehicle 20 of this embodiment travels in one of a plurality of travel modes, including a normal mode and a towing mode. The normal mode includes a CD (Charge Depleting) mode and a CS (Charge Sustaining) mode. The CD mode is a mode in which electric driving (EV driving) is prioritized over hybrid driving (HV driving) so as to reduce the power storage rate SOC of the battery 50. The EV driving mode is driving without operation of the engine 22. The HV driving mode is driving with operation of the engine 22. The CS mode is a mode in which both EV driving and HV driving are used so as to maintain the power storage rate SOC of the battery 50 within a control range including a target rate SOC* (for example, a threshold value Shv, described below). The towing mode is a mode in which EV driving is prohibited and only HV driving is performed. This increases the towing capacity of the vehicle compared to when the vehicle is running in EV driving mode.

[0031] Here, external charging and normal mode will be described. When the connector 56 is connected to an external power source while the hybrid vehicle 20 is parked at a charging point and a charging start condition is met, the hybrid vehicle 20 starts external charging control, which controls the charger 58 to perform external charging. When a charging end condition is met, the hybrid vehicle 20 ends the external charging control. The charging start condition may be, for example, a condition in which a user issues an instruction to start external charging. The charging end condition may be, for example, a condition in which the state of charge (SOC) of the battery 50 reaches or exceeds a threshold value Sfl near full charge. When the hybrid vehicle 20 starts up the system after external charging ends, in normal mode, the hybrid vehicle 20 first selects CD mode, and then transitions to CS mode when the state of charge (SOC) of the battery 50 reaches or exceeds a threshold value Shv that is somewhat lower than the threshold value Sfl.

[0032] Next, HV running and EV running will be described in order. In HV running, the HVECU 70 first sets a required torque Td* for running based on the accelerator opening Acc and the vehicle speed V, and then sets a required power Pd* for running based on the set required torque Td* and the rotation speed Nd of the drive shaft 37 (the rotation speed Nm2 of the motor MG2). Next, the HVECU 70 sets a required power Pe* for the engine 22 based on the required power Pd* and the required charging and discharging power Pb* of the battery 50, and then sets a target rotation speed Ne* and target torque Te* for the engine 22 and torque commands Tm1* and Tm2* for the motors MG1 and MG2 so that the required power Pe* is output from the engine 22 and the required torque Td* is output to the drive shaft 37. The HVECU 70 then transmits the target rotation speed Ne* and target torque Te* of the engine 22 to the engine ECU 24, and transmits torque commands Tm1* and Tm2* of the motors MG1 and MG2 to the motor ECU 40. The engine ECU 24 controls the operation of the engine 22 so that the engine 22 operates based on the target rotation speed Ne* and the target torque Te*. The motor ECU 40 controls the inverters 41 and 42 so that the motors MG1 and MG2 are driven based on the torque commands Tm1* and Tm2*.

[0033] In EV driving, the HVECU 70 first sets the required torque Td* in the same way as in HV driving. Next, the HVECU 70 sets the torque command Tm1* of the motor MG1 to value 0, sets the torque command Tm2* of the motor MG2 to the required torque Td*, and transmits the set torque commands Tm1* and Tm2* of the motors MG1 and MG2 to the motor ECU 40. The motor ECU 40 controls the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1* and Tm2*.

[0034] In the embodiment, in the normal mode and the towing mode, when the power storage percentage SOC of battery 50 falls to or below threshold value Smin, which is somewhat lower than threshold value Shv, the output of motor MG2 is relatively greatly restricted to protect battery 50. Therefore, when the power storage percentage SOC of battery 50 falls to or below threshold value Smin in the towing mode, the towing capacity of the vehicle may decrease relatively greatly.

[0035] Next, the operation of the hybrid vehicle 20 of this embodiment, particularly the operation when the hybrid vehicle 20 is in the normal mode and the towing mode is instructed, will be described. Figure 2 is a flowchart showing an example of a normal mode processing routine executed by the HVECU 70. This routine is repeatedly executed when the hybrid vehicle 20 is in the normal mode.

[0036] In the normal mode processing routine of FIG. 2, the HVECU 70 first determines whether the towing mode switch 91 is turned on (step S100). This process is to determine whether the towing mode has been commanded. If the HVECU 70 determines that the towing mode switch 91 is not turned on, it determines that the towing mode has not been commanded and ends this routine. In this case, the hybrid vehicle 20 continues in the normal mode.

[0037] When it is determined in step S100 that the towing mode switch 91 has been turned on, the HVECU 70 determines that the towing mode has been instructed, and determines whether the power storage percentage SOC of the battery 50 is higher than a threshold value Sref1 (step S110). Here, the threshold value Sref1 is a threshold value used to determine whether the conditions for permitting the towing mode are met. The threshold value Sref1 is set to a value that is somewhat larger than the threshold value Smin.

[0038] When the HVECU 70 determines in step S110 that the power storage percentage SOC of the battery 50 is higher than the threshold value Sref1, it determines that the conditions for permitting the towing mode are met and permits the towing mode (step S120). In this case, the hybrid vehicle 20 transitions from the normal mode to the towing mode. When the hybrid vehicle 20 transitions from EV running in the normal mode to the towing mode, the hybrid vehicle 20 initiates the towing mode by starting the engine 22 and commencing HV running. On the other hand, when the hybrid vehicle 20 transitions from HV running in the normal mode to the towing mode, the hybrid vehicle 20 initiates the towing mode while maintaining HV running.

[0039] Next, the HVECU 70 controls the display 63 of the navigation device 60 to display transition information indicating that the mode has been changed from the normal mode to the towing mode (step S130), and then ends this routine. The transition information may be notified by displaying it on the display unit 92, outputting an audio message from the speaker 93, or the like, instead of displaying it on the display 63.

[0040] When the HVECU 70 determines in step S110 that the power storage percentage SOC of the battery 50 is equal to or lower than the threshold value Sref1, it determines that the conditions for permitting the towing mode are not met, prohibits the towing mode (step S140), and controls the display 63 to display prohibition-related information indicating that the towing mode has been prohibited (step S150), and then ends this routine. In this case, the hybrid vehicle 20 continues in the normal mode. The prohibition-related information may be notified by displaying it on the display unit 92 or by audio output from the speaker 93, instead of by displaying it on the display 63. The prohibition-related information may be information indicating that the towing mode has been prohibited, information indicating that the towing mode has been prohibited because the power storage percentage SOC of the battery 50 is equal to or lower than the threshold value Sref1, or information indicating that a mode other than the towing mode (specifically, the normal mode) will be maintained. In addition to any of these, the prohibition-related information may also include information urging the driver to charge the battery 50. Examples of prohibition-related information include, "Tow mode has been prohibited because it is difficult to maintain vehicle speed in tow mode. Please charge the battery and then turn the tow mode switch on again." and "Tow mode has been prohibited. Please stop in a safe place, charge the battery, and then turn the tow mode switch on again."

[0041] When hybrid vehicle 20 is traveling in towing mode, accelerator pedal 83 is more likely to be depressed heavily, increasing the power requirement Pd* for traveling compared to when traveling in normal mode. This increases the output from battery 50 to meet the power requirement Pd*, which in turn reduces the battery's 50 power storage percentage SOC. If battery 50 power storage percentage SOC falls below threshold Smin during towing mode, the output of motor MG2 is significantly limited, resulting in a relatively large reduction in the vehicle's towing capacity, potentially affecting driving performance. In light of these factors, in this embodiment, when battery 50 power storage percentage SOC is determined to be below threshold Sref1, HVECU 70 prohibits towing mode and notifies the user that towing mode has been prohibited. This prevents the power storage percentage SOC from falling below threshold Smin during towing mode, resulting in a relatively large reduction in the vehicle's towing capacity, which could affect driving performance. Furthermore, the user is notified that towing mode has been prohibited. In this embodiment, when the towing mode is prohibited, the HVECU 70 turns the towing mode switch 91 back to OFF and notifies the driver by displaying a message to that effect on the display 63, for example.

[0042] Next, the processing in the towing mode will be described. Figure 3 is a flowchart showing an example of a towing mode processing routine executed by the HVECU 70. Execution of this routine begins when the towing mode is initiated.

[0043] In the towing mode processing routine of FIG. 3, the HVECU 70 first determines whether the towing mode switch 91 has been turned off (step S200). This process is for determining whether an instruction to cancel the towing mode has been issued. If the HVECU 70 determines that the towing mode switch 91 has not been turned off, it determines that an instruction to cancel the towing mode has not been issued, and determines whether the power storage ratio SOC of the battery 50 has reached a threshold value Sref2 or less (step S210). Here, the threshold value Sref2 is a threshold value for determining whether the towing mode termination condition for the power storage ratio SOC has been met. The threshold value Sref2 is set to a value that is less than the threshold value Sref1 and greater than the threshold value Smin. If the HVECU 70 determines that the power storage ratio SOC of the battery 50 has not reached a threshold value Sref2 or less, it determines that the towing mode termination condition for the power storage ratio SOC has not been met, and the process returns to step S200. In this case, the hybrid vehicle 20 continues in the towing mode.

[0044] When it is determined in step S200 that the towing mode switch 91 has been turned off, the HVECU 70 determines that an instruction to cancel the towing mode has been issued, and ends the towing mode (step S220). In this case, the hybrid vehicle 20 transitions from the towing mode to the normal mode. Next, the HVECU 70 controls the display 63 to display first termination-related information on the display 63, indicating that the towing mode has been terminated (step S230), and ends this routine. The first termination-related information may be notified by displaying it on the display unit 92 or by audio output from the speaker 93, instead of by displaying it on the display 63. The first termination-related information may be information indicating that the towing mode has been terminated, or may be information indicating that the hybrid vehicle 20 has transitioned to a mode other than the towing mode (specifically, the normal mode).

[0045] When it is determined in step S210 that the power storage percentage SOC of battery 50 has reached or exceeded threshold value Sref2, HVECU 70 determines that the towing mode termination condition for the power storage percentage SOC has been met, terminates the towing mode (step S240), controls display 63 to display second termination-related information related to the termination of the towing mode on display 63 (step S250), and terminates this routine. The second termination-related information may be notified by display on display unit 92, audio output from speaker 93, or the like, instead of by display on display 63. The second termination-related information may be the same as the first termination-related information, or may be information indicating that the towing mode has been terminated due to the power storage percentage SOC of battery 50 reaching or exceeding threshold value Sref2. By ending the towing mode when the power storage percentage SOC of battery 50 reaches or falls to a threshold value Sref2 that is greater than threshold value Smin, i.e., by ending the towing mode before the power storage percentage SOC reaches or falls to or falls to threshold value Smin, it is possible to prevent the power storage percentage SOC from falling to or below threshold value Smin while traveling in the towing mode, thereby preventing a relatively large decrease in the towing capacity of the vehicle and affecting driving performance. In addition, the user can be notified that the towing mode has ended.

[0046] In the hybrid vehicle 20 of this embodiment described above, when the towing mode switch 91 is turned on, if the power storage percentage SOC of the battery 50 is higher than the threshold value Sref1, the towing mode is permitted and a notification to that effect is given. Alternatively, if the power storage percentage SOC of the battery 50 is equal to or lower than the threshold value Sref1, the towing mode is prohibited and a notification to that effect is given. This prevents a relatively large decrease in the towing capacity of the vehicle while traveling in towing mode, which would affect the vehicle's driving performance. Furthermore, the user can be notified that towing mode is prohibited.

[0047] In the above-described embodiment, the HVECU 70 determines that the towing mode has been instructed when the towing mode switch 91 is turned on, and permits or prohibits the towing mode depending on whether the power storage percentage SOC of the battery 50 is higher than the threshold value Sref1. However, this is not limiting. For example, the HVECU 70 may execute the normal mode processing routine of FIG. 4 or 5 instead of the normal mode processing routine of FIG. 2. These routines will be described in order below.

[0048] The normal mode processing routine of FIG. 4 will be described. This routine differs from the normal mode processing routine of FIG. 2 in that the processing of step S100 is replaced by the processing of step S101. In this routine, the HVECU 70 first determines whether the vehicle and the towed object are connected (step S101). Like the processing of step S100, this processing determines whether the towing mode has been commanded. This processing is performed, for example, based on a signal from a connection detection sensor that detects whether the vehicle and the towed object are connected. If the HVECU 70 determines that the vehicle and the towed object are not connected, it determines that the towing mode has not been commanded and ends this routine. On the other hand, if the HVECU 70 determines that the vehicle and the towed object are connected, it determines that the towing mode has been commanded and proceeds to step S110. As a result, when the vehicle and the towed object are connected, it determines that the towing mode has been commanded and it is possible to permit or prohibit the towing mode depending on whether the power storage percentage SOC of the battery 50 is higher than the threshold value Sref1.

[0049] When the HVECU70 executes the normal mode processing routine of FIG. 4, the HVECU70 may determine whether or not a command to cancel the towing mode has been issued by determining whether or not the connection between the vehicle and the towed object has been released, instead of processing step S200 of the towing mode processing routine of FIG. 3.

[0050] The normal mode processing routine of FIG. 5 will be described. This routine differs from the normal mode processing routine of FIG. 2 in that the processing of step S100 is replaced with the processing of step S102. In this routine, the HVECU 70 first determines whether the vehicle load exceeds a predetermined load (step S102). This processing, like the processing of step S100, determines whether the towing mode has been commanded. The HVECU 70 may estimate the vehicle load based on the vehicle speed V and the required torque Td* or the required power Pd*, and determine whether the vehicle load exceeds the predetermined load based on whether the estimated vehicle load exceeds the assumed load of the vehicle and occupants. The HVECU 70 may estimate the weight based on the required torque Td* or the required power Pe* and the road gradient θrd, and determine whether the vehicle load exceeds the predetermined load based on whether the estimated weight exceeds the assumed weight of the vehicle and occupants. If the HVECU 70 determines in step S102 that the vehicle load is less than the predetermined load, it determines that the towing mode has not been instructed and ends this routine. On the other hand, if the HVECU 70 determines that the vehicle load exceeds the predetermined load, it determines that the towing mode has been instructed and proceeds to step S110. As a result, when the vehicle load exceeds the predetermined load, it can determine that the towing mode has been instructed and permit or prohibit the towing mode depending on whether the power storage percentage SOC of the battery 50 is higher than the threshold value Sref1.

[0051] When the HVECU70 executes the normal mode processing routine of FIG. 5, the HVECU70 may determine whether or not a command to cancel the towing mode has been issued by determining whether or not the vehicle load has become less than a predetermined load, instead of processing step S200 of the towing mode processing routine of FIG. 3.

[0052] In the above-described embodiment, the threshold value Sref1 is a constant value, but this is not limiting. For example, the HVECU 70 may execute any of the normal mode processing routines shown in Figures 6, 7, and 8 instead of the normal mode processing routine shown in Figure 2. These will be described in order below.

[0053] The normal mode processing routine of FIG. 6 will be described. This routine differs from the normal mode processing routine of FIG. 2 in that the processing of step S104 has been added. In this routine, when the HVECU 70 determines in step S100 that the towing mode switch 91 has been turned on, it sets the threshold value Sref1 based on the altitude EL from the altitude sensor 90, i.e., the altitude EL of the current location of the vehicle (step S104), and proceeds to step S110. In this case, the HVECU 70 sets the threshold value Sref1 based on, for example, the altitude EL and a first map. The first map is a map that shows the relationship between the altitude EL and the threshold value Sref1, and is determined in advance through experiments, analysis, machine learning, or the like. The HVECU 70 applies the altitude EL to the first map and derives and sets the corresponding threshold value Sref1 from the first map. In the first map, the threshold value Sref1 is set to increase as the altitude EL increases. The threshold value Sref1 may also be set to increase continuously (linearly or curvedly) as the altitude EL increases. The threshold value Sref1 may be set to increase discontinuously (in a stepped manner) as the altitude EL increases. The threshold value Sref1 may be set to be higher when the altitude EL is equal to or greater than the threshold value ELref compared to when the altitude EL is less than the threshold value ELref. The higher the altitude EL, the lower the air density. Therefore, the higher the altitude EL, the more likely the output of the engine 22 is to decrease, and the more likely the output from the battery 50 is to increase to meet the required power Pd* for traveling, which in turn reduces the power storage ratio SOC of the battery 50. Therefore, during traveling in the towing mode, the higher the altitude EL, the more likely the power storage ratio SOC is to fall below the threshold value Smin. In light of this, in this modified example, the HVECU 70 sets the threshold value Sref1 to increase as the altitude EL increases. This makes it more difficult to enable the towing mode at higher altitudes. As a result, it is possible to prevent the power storage ratio SOC from falling below the threshold value Smin during traveling in the towing mode, which would result in a relatively large decrease in the vehicle's towable weight and thereby affect the traveling performance.

[0054] In the normal mode processing routine of Fig. 6, the HVECU 70 sets the threshold value Sref1 based on the altitude EL of the current location of the vehicle, but this is not limited to this. For example, the HVECU 70 may use the altitude ELsr of the planned travel route from the current location of the vehicle to the destination instead of the altitude EL of the current location of the vehicle. The altitude ELsr may be the average value of the altitudes of each point on the planned travel route, or the maximum altitude of each point.

[0055] The normal mode processing routine of FIG. 7 will be described. This routine differs from the normal mode processing routine of FIG. 2 in that the processing of step S105 has been added. In this routine, when the HVECU 70 determines in step S100 that the towing mode switch 91 has been turned on, it sets the threshold value Sref1 based on the road surface gradient θrd from the gradient sensor 89, i.e., the road surface gradient θrd at the vehicle's current location (step S105), and proceeds to step S110. In this case, the HVECU 70 sets the threshold value Sref1 based on, for example, the road surface gradient θrd and a second map. The second map is a map that indicates the relationship between the road surface gradient θrd and the threshold value Sref1, and is determined in advance through experiments, analysis, machine learning, or the like. The HVECU 70 applies the road surface gradient θrd to the second map and derives and sets the corresponding threshold value Sref1 from the second map. In the second map, the threshold value Sref1 is determined to be higher as the road surface gradient θrd increases. The threshold value Sref1 may be set to increase continuously (linearly or curvedly) as the road surface gradient θrd increases. The threshold value Sref may be set to increase discontinuously (stepwise) as the road surface gradient θrd increases. The threshold value Sref1 may be set to be higher when the road surface gradient θrd is equal to or greater than the threshold value θrdref compared to when the road surface gradient θrd is less than the threshold value θrdref. The greater the road surface gradient θrd, the more likely the vehicle is to decelerate, and therefore the greater the accelerator opening Acc. Therefore, the greater the road surface gradient θrd, the greater the power requirement Pd* for traveling, which in turn increases the output from the battery 50 to meet the power requirement Pd*, and the more likely the battery 50's power storage rate SOC is to decrease. Therefore, during traveling in the towing mode, the greater the road surface gradient θrd, the more likely the power storage rate SOC is to fall below the threshold value Smin. Based on this, in this modified example, the HVECU 70 sets the threshold value Sref1 to increase as the road surface gradient θrd increases. As a result, the greater the road surface gradient θrd, the less likely it is to enable the towing mode. As a result, it is possible to prevent the power storage ratio SOC from falling below the threshold value Smin during driving in the towing mode, which would cause a relatively large decrease in the towing capacity of the vehicle and affect the driving performance.

[0056] In the normal mode processing routine of Fig. 7, the HVECU 70 sets the threshold value Sref1 based on the road surface gradient θrd at the current location of the vehicle, but this is not limited to this. For example, the HVECU 70 may use the road surface gradient θrdsr of the planned travel route from the current location of the vehicle to the destination, instead of the road surface gradient θrd at the current location of the vehicle. The road surface gradient θrdsr may be the average value or the maximum value of the road surface gradient at each point on the planned travel route.

[0057] The normal mode processing routine of FIG. 8 will be described. This routine differs from the normal mode processing routine of FIG. 2 in that the processing of step S106 has been added. In this routine, when it is determined in step S100 that the towing mode switch 91 has been turned on, the HVECU 70 sets the threshold value Sref1 based on whether the vehicle is running in EV driving or HV driving (step S106), and then proceeds to step S110. In this case, when the vehicle is running in EV driving, the HVECU 70 sets a higher value for the threshold value Sref1 than when the vehicle is running in HV driving. When transitioning from EV driving to towing mode in normal mode, the towing mode is initiated by starting the engine 22 and initiating HV driving. On the other hand, when transitioning from HV driving to towing mode in normal mode, the towing mode is initiated while maintaining HV driving. Therefore, when transitioning from EV driving to towing mode in normal mode, the power storage percentage SOC of the battery 50 at the time of starting towing mode is likely to be lower than when transitioning from HV driving to towing mode in normal mode. Based on this, in this modification, the HVECU 70 sets the threshold value Sref1 to a larger value when the vehicle is running in EV mode than when the vehicle is running in HV mode. This makes it more difficult to permit the towing mode when the vehicle is running in EV mode than when the vehicle is running in HV mode. As a result, it is possible to prevent the power storage ratio SOC from falling below the threshold value Smin while the vehicle is running in tow mode, which would cause a relatively large decrease in the vehicle's towing capacity and affect the driving performance.

[0058] In the normal mode processing routine of Fig. 8, the HVECU 70 sets the threshold value Sref1 based on whether the vehicle is running in EV mode or HV mode, but this is not limiting. For example, the HVECU 70 may set the threshold value Sref1 based on whether the vehicle is running in CD mode or CS mode in normal mode.

[0059] 6 to 8, the HVECU 70 sets the threshold value Sref1 based on one of the altitude EL, altitude ELsr, road surface gradient θrd, road surface gradient θrdsr, whether the vehicle is running in EV mode or HV mode, and whether the vehicle is running in CD mode or CS mode in normal mode. However, this is not limiting. For example, the HVECU 70 may set the threshold value Sref1 based on multiple of the altitude EL, altitude ELsr, road surface gradient θrd, road surface gradient θrdsr, whether the vehicle is running in EV mode or HV mode, and whether the vehicle is running in CD mode or CS mode in normal mode.

[0060] The processing of step S100 in the normal mode processing routine of Figures 6 to 8 may be replaced with the processing of step S101 in the normal mode processing routine of Figure 4, or may be replaced with the processing of step S102 in the normal mode processing routine of Figure 5. In these cases, the processing of step S200 in the towing mode processing routine of Figure 3 may also be replaced with processing to determine whether the connection between the vehicle and the towed object has been released, or with processing to determine whether the vehicle load has become less than a predetermined load.

[0061] In the embodiment, the battery 50 is used as the power storage device, but the present invention is not limited to this. For example, a capacitor may be used as the power storage device.

[0062] In the embodiment, the hybrid vehicle 20 includes the engine ECU 24, the motor ECU 40, the battery ECU 52, and the HVECU 70. However, the present invention is not limited to this. For example, at least two of the engine ECU 24, the motor ECU 40, the battery ECU 52, and the HVECU 70 may be integrated.

[0063] In the embodiment, the hybrid vehicle 20 is provided with the connector 56, the charging power line 57, and the charger 58 for AC charging, in which the battery 50 is charged using AC power from an external AC power source; however, this is not limiting. For example, the hybrid vehicle 20 does not have to be provided with the connector 56, the charging power line 57, and the charger 58. That is, the hybrid vehicle 20 may be a vehicle that does not require external charging. Furthermore, instead of or in addition to the connector 56, the charging power line 57, and the charger 58, the hybrid vehicle 20 may be provided with a DC charging connector and a DC charging power line for DC charging, in which the battery 50 is charged using DC power from an external DC power source.

[0064] In the above-described embodiment, the hybrid vehicle 20 includes the engine 22, the planetary gear 30, the motors MG1 and MG2, and the battery 50, but is not limited to this. For example, as shown in a hybrid vehicle 120 of Fig. 9, the hybrid vehicle 20 may include the engine 22, the clutch CL, the motor MG, the inverter IV, the battery 50, and the transmission TM. In the hybrid vehicle 120, the engine 22 is connected to the drive wheels 39a and 39b via the clutch CL, the motor MG, the transmission TM, and the drive shaft 37, and the inverter IV that drives the motor MG and the battery 50 are connected to a drive power line 54.

[0065] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be described below. In the embodiment, the engine 22 corresponds to the "engine," the motor MG2 corresponds to the "motor," the battery 50 corresponds to the "power storage device," and the HVECU 70, the engine ECU 24, and the motor ECU 40 correspond to the "control device." Also, at least one of the display 63, the display unit 92, and the speaker 93 corresponds to the "alarm device."

[0066] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0067] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0068] The present disclosure is applicable to the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0069] 20,120 Hybrid vehicle, 22 Engine, 23 Crankshaft, 23a Crank position sensor, 24 Engine ECU, 30 Planetary gear, 37 Drive shaft, 38 Differential gear, 39a, 39b Drive wheels, 40 Motor ECU, 41, 42 Inverter, 43, 44 Rotational position sensor, 50 Battery, 51i Current sensor, 51t Temperature sensor, 51v Voltage sensor, 52 Battery ECU, 54 Drive power line, 56 Connector, 57 Charging power line, 58 Charger, 60 Navigation device, 61 Main unit, 62 GPS antenna, 63 Display, 70 HVECU, 80 Power switch, 81 Shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor, 87 Vehicle speed sensor, 88 Acceleration sensor, 89 gradient sensor, 90 altitude sensor, 91 towing mode switch, 92 display, 93 speaker, 120 hybrid vehicle, CL clutch, MG, MG1, MG2 motor, TM transmission.

Claims

1. A hybrid vehicle including an engine and a motor for running, an electricity storage device that exchanges electric power with the motor, and a control device that controls the engine and the motor so that the vehicle runs with the engine operating in a towing mode, When the towing mode is instructed, the control device permits the towing mode if a power storage rate of the power storage device is higher than a threshold value, and prohibits the towing mode if the power storage rate is equal to or lower than the threshold value. Hybrid car.

2. The hybrid vehicle according to claim 1, further comprising an alarm device for notifying information; When the control device prohibits the towing mode, the control device controls the notification device to notify prohibition-related information that the towing mode has been prohibited. Hybrid car.

3. 3. The hybrid vehicle according to claim 1 or 2, a towing mode switch for indicating the towing mode; The control device determines that the towing mode has been instructed when the towing mode switch is operated by a user. Hybrid car.

4. 3. The hybrid vehicle according to claim 1 or 2, The control device determines that the towing mode has been instructed when the vehicle and the towed object are connected. Hybrid car.

5. 3. The hybrid vehicle according to claim 1 or 2, The control device determines that the towing mode is commanded when the vehicle load exceeds a predetermined load. Hybrid car.

6. 3. The hybrid vehicle according to claim 1 or 2, the control device sets the threshold value so that the threshold value increases as the altitude of the current location of the vehicle and / or the planned travel route increases; Hybrid car.

7. 3. The hybrid vehicle according to claim 1 or 2, the control device sets the threshold value so that the threshold value increases as the road surface gradient of the current location of the vehicle and / or the planned travel route increases toward an uphill road; Hybrid car.

8. 3. The hybrid vehicle according to claim 1 or 2, The control device sets the threshold value higher when the vehicle is traveling with the engine stopped than when the vehicle is traveling with the engine running. Hybrid car.

9. 3. The hybrid vehicle according to claim 1 or 2, the control device terminates the towing mode when the power storage rate reaches or is equal to or lower than a second threshold value that is lower than the threshold value during traveling in the towing mode. Hybrid car.

10. 10. The hybrid vehicle according to claim 9, further comprising an alarm device for notifying information; When the towing mode is terminated because the power storage ratio has reached or exceeded the second threshold during traveling in the towing mode, the control device controls the notification device to provide termination-related information related to the termination of the towing mode. Hybrid car.

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