Patent Description:
In a hybrid vehicle mounted with a motor generator as a drive source and an engine as an electric power source, one of a plurality of control modes is selected to control the vehicle according to the selected control mode. The control modes include, for example, a charge depleting (CD) mode and a charge sustaining (CS) mode. The CD mode allows continuous electric traveling as much as possible while the engine is turned off by consuming electric power stored in an onboard battery. The CS mode allows easier startup of the engine than the CD mode, and allows the vehicle to travel while maintaining the state of charge of the onboard battery in a constant range by using the engine and the motor generator.

When such a hybrid vehicle travels to a destination set by a user, switching control is performed for switching the control modes as appropriate depending on the situation of a travel route.

For example, <CIT>discloses a technique for setting a travel route to a destination, and selecting one of an EV mode and an HV mode for each of a plurality of sections of the set travel route except for one or more sections before the destination, the EV mode being a mode for electric traveling, the HV mode being a mode using the engine and the motor generator.

<CIT> provides a plug-in hybrid vehicle that can charge an electric storage device for running by an outside power supply. <CIT> provides a cruising distance calculation apparatus for a hybrid vehicle that includes a motor and an engine for driving a generator. <CIT> provides a plug-in hybrid vehicle capable of charging a travelling power storage device by an external power supply.

The hybrid vehicle having the aforementioned configuration may notify the user of the effect of the switching control by indicating how the travel distance, by electric traveling using electric power of the onboard battery when the switching control is executed in accordance with the travel situations, varies as compared with the travel distance when the switching control is not executed. Therefore, it is required to accurately calculate the travel distance by electric driving using the electric power from the onboard battery in both the case where the switching control is executed and the case where the switching control is not executed.

However, in the case where, while traveling to the destination, the vehicle performs electric traveling during a period of time until the switching control is restated after an IG switch is turned off and then turned on, the travel distance during the period of time, which is to be calculated as the travel distance when the switching control is executed unless the IG switch is turned off, may not be counted as the travel distance when the switching control is executed. The IG switch is a switch that is turned on when the startup operation of the control system of the vehicle is performed and turned off when stop operation of the control system of the vehicle is performed. Hence, it may be difficult to accurately calculate the travel distance by electric driving using the electric power of the onboard battery in the case where the switching control is executed according to the traveling situations and in the case where the switching control is not executed.

The present invention has been made to solve the above problem, and it is an object of the present invention to provide a hybrid vehicle that accurately calculates the travel distance by electric driving using electric power from an onboard battery in the case where switching control is performed according to the driving situations and in the case where the switching control is not performed.

A hybrid vehicle according to an aspect of the present invention incudes an electric motor, a power storage device, an engine, and a controller. The electric motor is configured to generate drive force for the vehicle. The power storage device is configured to supply electric power to the electric motor. The engine is configured to generate electric power generated to charge the power storage device. The controller is configured to control the engine and the electric motor in accordance with one of a plurality of control modes. The modes include a charge depleting (CD) mode and a charge sustaining (CS) mode. The controller is configured to execute switching control for switching the control modes in accordance with a travel plan by using external information obtained from the outside of the vehicle after a predetermined condition is established, the travel plan including a travel route of the vehicle to a destination, the travel route including a plurality of sections assigned with one of the CD mode and the CS mode. The controller is configured to calculate, when there is an execution history of the switching control before the predetermined condition is established, a first travel distance and a second travel distance by using the execution history, the first travel distance being a distance by electric traveling using electric power from the power storage device with the engine being in a stopped state when the switching control is not executed, the second travel distance being a distance by the electric traveling with the engine being in the stopped state when the switching control is executed. The controller is configured to calculate the second travel distance by adding a travel distance by the electric traveling with the engine being in the stopped state during a period until the switching control is started after the predetermined condition is satisfied.

With the configuration, the first travel distance and the second travel distance are calculated by using the execution history, and the second travel distance is calculated by adding the travel distance by the electric traveling with the engine being in the stopped state during the period until the switching control is started after the predetermined condition is satisfied. Therefore, it is possible to accurately calculate the first travel distance and the second travel distance.

In the aspect, the predetermined condition includes a condition that a control system of the vehicle starts up.

With the configuration, when an execution history of the switching control is present after the control system of the vehicle starts up, the first travel distance and the second travel distance are calculated by using the execution history, and the second travel distance is calculated by adding the travel distance by the electric traveling with the engine being in the stopped state during the period until the switching control is started after the control system is started up. Therefore, it is possible to accurately calculate the first travel distance and the second travel distance.

Furthermore in the aspect, the predetermined condition includes a condition that the switching control is returned from a temporarily interrupted state.

Accordingly, after the switching control is returned from the temporarily interrupted state, the first travel distance and the second travel distance are calculated by using the execution history of the switching control, and the second travel distance is calculated by adding the travel distance by the electric traveling with the engine being in the stopped state during the period until the switching control is started after the switching control is returned. Therefore, it is possible to accurately calculate the first travel distance and the second travel distance.

Furthermore in the aspect, the controller is further configured to put the switching control in the temporarily interrupted state, when the switching control is in operation in at least any one of cases including a case where abnormal temperature occurs in the power storage device, a case where electric power in the power storage device is depleted, a case where the vehicle is out of the travel route, and a case where the engine is started up in the CD mode.

With the configuration, it is possible to accurately calculate the first travel route and the second travel route, even when the switching control is returned from the temporarily interrupted state in at least any of the cases including the case where abnormal temperature occurs in the power storage device, the case where electric power in the power storage device is depleted, the case where the vehicle is out of the travel route, and the case where the engine is started up in the CD mode.

Furthermore in the aspect, the execution history includes information about the first travel distance and the second travel distance during a period before the predetermined condition is established.

With the configuration, it is possible to accurately calculate the first travel distance and the second travel distance to the destination using the execution history.

Furthermore in the aspect, the vehicle further includes at least one of a communication device configured to be communicable with an external mobile terminal and a notification device configured to notify predetermined information. The controller notifies information about an effect of executing the switching control using at least one of the notification device and the mobile terminal via the communication device.

This configuration enables the user to recognize the information about the effect of executing the switching control.

Furthermore in the aspect, the vehicle further includes a communication device configured to be communicable with a mobile terminal via an external server. The controller transmits information about the effect of executing the switching control to the mobile terminal.

Furthermore in the aspect, unless there is the execution history, the controller is configured not to execute processing to calculate the second travel distance by adding the travel distance by electric driving with the engine in the stopped state during the period until switching control is started after the predetermined condition is established.

With the configuration, it is possible to appropriately calculate the second travel distance depending on the presence or absence of the execution history.

According to the present invention, it is possible to provide the hybrid vehicle that accurately calculates the travel distance by electric driving using electric power from an onboard battery in the case where switching control is executed according to the traveling situations and in the case where the switching control is not executed.

Embodiments of the present invention will be described hereinafter in detail with reference to the drawings. Note that identical or corresponding component members are designated by identical reference signs to avoid repetition of the description thereof.

Hereinafter, description is given of an example of the configuration of a hybrid vehicle according to an embodiment of the present invention. <FIG> shows an example of the configuration of a hybrid vehicle <NUM> (hereinafter referred to as the vehicle <NUM>). The vehicle <NUM> will be described, for example, as a series-parallel hybrid vehicle.

As shown in <FIG>, the vehicle <NUM> includes a first motor generator (hereafter referred to as a first MG) <NUM>, a second motor generator (hereafter referred to as a second MG) <NUM>, an engine <NUM>, a power split device <NUM>, a drive wheel <NUM>, a power control unit (PCU) <NUM>, a system main relay (SMR) <NUM>, a charging relay <NUM>, a charging device <NUM>, an inlet <NUM>, a power storage device <NUM>, a monitoring unit <NUM>, a hybrid vehicle electronic control unit (HV-ECU) <NUM>, an IG switch <NUM>, a sensor group <NUM>, a human machine interface (HMI) device <NUM>, a navigation ECU <NUM>, a position detector <NUM>, a traffic information receiver <NUM>, an air conditioner ECU (hereafter referred to as AC-ECU) <NUM>, an air conditioner <NUM>, and a mode selector switch <NUM>.

The first MG <NUM> and the second MG <NUM> are three-phase alternate current rotary electric machines which are, for example, permanent-magnet type synchronous electric motors including a rotor having a permanent magnet embedded therein. The first MG <NUM> and the second MG <NUM> both have functions as an electric motor (motor) and as an electric generator (generator). The first MG <NUM> and the second MG <NUM> are connected to the power storage device <NUM> via the PCU <NUM>.

The first MG <NUM> is driven by an inverter included in the PCU <NUM> to rotate an output shaft of the engine <NUM> when, for example, the engine <NUM> is started up. In generating electric power, the first MG <NUM> generates electric power by receiving motive power from the engine <NUM>. The electric power generated by the first MG <NUM> is stored in the power storage device <NUM> via the PCU <NUM>.

The second MG <NUM> is driven by the inverter included in the PCU <NUM> when, for example, the vehicle <NUM> travels. The motive power of the second MG <NUM> is transmitted to the drive wheel <NUM> via a motive power transmission gear (not illustrated) such as a differential gear or a reduction gear. The second MG <NUM> is also driven by the drive wheel <NUM> when, for example, the vehicle <NUM> is braking, and thereby the second MG <NUM> operates as an electric power generator to perform regenerative braking. The electric power generated in the second MG <NUM> is stored in the power storage device <NUM> via the PCU <NUM>.

The engine <NUM> is a publicly known internal combustion engine that burns fuel (gasoline or gas oil), such as a gasoline engine and a diesel engine, to output motive power. The engine <NUM> is configured such that the operating states, such as a throttle opening angle (intake air amount), a fuel supply amount, and ignition timing, can electrically be controlled by the HV-ECU <NUM>. The HV-ECU <NUM> controls a fuel injection amount, the ignition timing, the intake air amount, or the like, of the engine <NUM> such that the engine <NUM> operates at a target speed and a target torque set based on the states of the vehicle <NUM>.

The power split device <NUM> splits the motive power of the engine <NUM> to a path transmitting the motive power to the drive wheel <NUM> and to a path transmitting the motive power to the first MG <NUM>. The power split device <NUM> is constituted of a planetary gear mechanism including, for example, a sun gear, a ring gear, a pinion gear, and a carrier.

The PCU <NUM> is an electric power converter that converts electric power between the power storage device <NUM> and the first MG <NUM>, and between the power storage device <NUM> and the second MG <NUM> based on a control signal from the HV-ECU <NUM>. The PCU <NUM> is configured to include an inverter (not illustrated) that converts direct-current electric power from the power storage device <NUM> to alternating-current electric power to drive the first MG <NUM> or the second MG <NUM>, and a converter (not illustrated) that regulates the voltage level of the direct-current electric power supplied to the inverter from the power storage device <NUM>.

The SMR <NUM> is electrically connected between the power storage device <NUM> and the PCU <NUM>. Closing and opening of the SMR <NUM> are controlled in accordance with a control signal from the HV-ECU <NUM>. For example, the SMR <NUM> is controlled to be closed when startup operation of the control system is performed and the IG switch <NUM> is put in an ON state.

The power storage device <NUM> is a direct-current power source configured to be rechargeable, and is a secondary battery such as a nickel-hydrogen battery or a lithium-ion battery including a solid or liquid electrolyte. As the power storage device <NUM>, capacitors such as electric double-layered capacitors can also be adopted. The power storage device <NUM> supplies electric power for generating travel driving force of the vehicle <NUM> to the PCU <NUM>. In addition, the power storage device <NUM> is charged by the electric power generated by electric power generating operation using the first MG <NUM> and the engine <NUM>, charged by the electric power generated by the regenerative braking of the second MG <NUM>, and discharged by the driving operation of the first MG <NUM> or the second MG <NUM>.

The monitoring unit <NUM> monitors the status of the power storage device <NUM>. The monitoring unit <NUM> includes, for example, a voltage detector <NUM>, a current detector <NUM>, and a temperature detector <NUM>. The voltage detector <NUM> detects a voltage VB across the terminals of the power storage device <NUM>. The current detector <NUM> detects a current IB input into and output from the power storage device <NUM>. The temperature detector <NUM> detects a temperature TB of the power storage device <NUM>. The respective detectors output the results of detection to the HV-ECU <NUM>.

The charging relay <NUM> is electrically connected between the SMR <NUM> and the charging device <NUM>. Closing and opening of the charging relay <NUM> are controlled in accordance with a control signal from the HV-ECU <NUM>.

The charging device <NUM> is electrically connected between the charging relay <NUM> and the inlet <NUM>. The charging device <NUM> is, for example, an AC-DC converter (inverter). The charging device <NUM> converts the alternating-current electric power supplied from the external power source <NUM> via a connector <NUM> described later and the inlet <NUM> into direct-current electric power, and output the direct-current electric power to the charging relay <NUM>. The charging device <NUM> is controlled in accordance with a control signal from the HV-ECU <NUM>.

The charging device <NUM> is not specifically limited to performing AC-DC conversion operation. When the direct-current electric power is supplied from the inlet <NUM> to the charging device <NUM>, the charging device <NUM> may be configured to operate as a DC-DC converter.

The inlet <NUM> is configured to allow insertion of the connector <NUM> through mechanical coupling such as fitting. As the connector <NUM> is inserted into the inlet <NUM>, electrical connection between the vehicle <NUM> and the external power source <NUM> is established. In this case, when the SMR <NUM> and the charging relay <NUM> are closed, the external power source <NUM> can supply electric power to the power storage device <NUM> via the charging device <NUM> and the charging relay <NUM>. In the following description, charging the power storage device <NUM> using the electric power from the external power source <NUM> is referred to as plug-in charging.

The HV-ECU <NUM> includes a central processing unit (CPU) <NUM> and a memory (including a non-volatile memory that can maintain the memory state even after the IG is turned off, such as a read only memory (ROM), and a random access memory (RAM)) <NUM>. The HV-ECU <NUM> controls the devices in the vehicle <NUM> (such as the engine <NUM>, the PCU <NUM>, the SMR <NUM>, the charging relay <NUM>, the charging device <NUM>, and the HMI device <NUM>) to put the vehicle <NUM> in a desired state, based on the signals received from the monitoring unit <NUM>, the IG switch <NUM>, the sensor group <NUM> and the mode selector switch <NUM> and on information such as maps and programs stored in the memory <NUM>. Various controls executed by the HV-ECU <NUM> can be processed by dedicated hardware (electronic circuits) as well as by software.

The HV-ECU <NUM> calculates, for example, a state of charge (SOC) indicating the remaining capacity of the power storage device <NUM>, using the result of detection by the monitoring unit <NUM> while the vehicle <NUM> is operated. The SOC expresses as a percentage a ratio of the current storage amount to the fully charged storage amount of the power storage device <NUM>. For example, as the calculation method of the SOC, various publicly known methods, such as a method of current value accumulation (Coulomb count), or a method of estimating open circuit voltage (OCV), can be adopted.

The IG switch <NUM> is a switch that is turned on when the startup operation of the control system of the vehicle <NUM> is performed and turned off when stop operation of the control system of the vehicle <NUM> is performed.

The HV-ECU <NUM> is connected to the sensor group <NUM>, the HMI device <NUM> and the navigation ECU <NUM> via a communication bus <NUM>. The navigation ECU <NUM> is connected to the position detector <NUM> and the traffic information receiver <NUM>.

The sensor group <NUM> includes, for example, an accelerator pedal sensor, a vehicle speed sensor, and a brake pedal sensor. The accelerator pedal sensor detects the amount of accelerator pedal operation by the user. The vehicle speed sensor detects the vehicle speed of the vehicle <NUM>. The brake pedal sensor detects the amount of brake pedal operation by the user. The respective sensors output the detection results to the HV-ECU <NUM>.

The HMI device <NUM> provides the user with information to assist the operation of the vehicle <NUM>. For example, the HMI device <NUM> is a touch panel display provided in the cabin of the vehicle <NUM>, the touch panel including a speaker. The HMI device <NUM> provides (notifies) a variety of information to the user by outputting visual information (graphic information, text information), audio information (voice information, sound information), or the like.

The HMI device <NUM> functions as a display that receives the current position of the vehicle <NUM> and map information and traffic congestion information around the current position, etc. from the navigation ECU <NUM> via the communication bus <NUM>, and displays the current position of the vehicle <NUM> along with the map information and traffic congestion information therearound.

The HMI device <NUM> also functions as a user-accessible touch panel that allows the user to change the scale of the displayed map or to input a destination of the vehicle <NUM> by touching the touch panel. When the destination is input on the HMI device <NUM>, the destination information is transmitted to the navigation ECU <NUM> via the communication bus <NUM>.

The devices connected to the communication bus <NUM> may be configured to be communicable with each other via the communication bus <NUM> by controller area network (CAN) communication, or may be configured to be communicable with each other via wireless communication in place of or in addition to the communication bus <NUM>.

The navigation ECU <NUM> includes a CPU which is not illustrated and a memory. In the memory, a map information database (DB) is constructed. The navigation ECU <NUM> outputs the current position of the vehicle <NUM>, the map information and traffic congestion information therearound, etc. to the HMI device <NUM> and the HV-ECU <NUM>, based on various information stored in the map information DB, various information detected by the position detector <NUM>, and various information received from the traffic information receiver <NUM>.

In addition, the navigation ECU <NUM> outputs map information and road traffic information on a travel route from the current position of the vehicle <NUM> to the destination (hereinafter referred to as "look-ahead information") to the HV-ECU <NUM> at a given time (for example, every few tens of seconds).

The map information DB stores map information. The map information includes data about "nodes" that indicate intersections, stops, etc., "links" that are made up of connections of nodes, and "facilities" (buildings, parking lots, etc.) that are located along the links. The map information also includes position information on each node, distance information on each link, road type information included in each link (information such as urban areas, highways, general roads, etc.), and gradient information on each link. The map information is not limited to information acquired by reading from the map information DB. The map information may be acquired sequentially through communication with an external database in addition to or in place of the information acquired from the map information DB.

The position detector <NUM> acquires the current position of the vehicle <NUM> based on, for example, signals (radio wave) from global positioning system (GPS) satellites, and outputs a signal indicating the current position of the vehicle <NUM> to the navigation ECU <NUM>. The method for acquiring the current position of the vehicle <NUM> may be a method for acquiring the current position using satellites capable of detecting the position, other than GPS satellites, or a method for acquiring the current position by exchanging prescribed information with mobile base stations or wireless local area network (LAN) access points.

The traffic information receiver <NUM> receives prescribed traffic information. The prescribed traffic information includes, for example, road traffic information provided by FM multiplex broadcasts, and road traffic information collected from probe vehicles or probe centers. The road traffic information includes at least traffic congestion information, and may also include other road control information and parking information. The traffic information is updated, for example, every few minutes.

The AC-ECU <NUM> controls operation of the air conditioner <NUM> described later. The AC-ECU <NUM> includes a CPU and a memory which are not illustrated. The AC-ECU <NUM> is configured to be able to acquire information on operation status of the air conditioner <NUM> (for example, information on energy consumption, etc.) and transmit the acquired information to the HV-ECU <NUM>. In addition, the AC-ECU <NUM> is configured to be able to generate, for example, a control command value for the air conditioner <NUM> with a set temperature in the cabin of vehicle <NUM> as a target value, and to transmit the generated control command value as a control signal to the air conditioner <NUM>.

The air conditioner <NUM> is configured to allow temperature-controlled air to be emitted from air vents provided in the vehicle <NUM> by using an electrical device, such as a compressor, that can regulate the temperature in the cabin of the vehicle <NUM>.

The mode selector switch <NUM> is configured to allow selection of one of a plurality of control modes. The control modes will be described later. Upon reception of the user's operation, the mode selector switch <NUM> transmits to the HV-ECU <NUM> a signal indicating that the operation has been performed.

In the present embodiment, the vehicle <NUM> is controlled by the HV-ECU <NUM> in accordance with any one of the control modes. The control modes include a charge depleting (CD) mode and a charge sustaining (CS) mode. The CD mode is a control mode that uses discharged electric power from the power storage device <NUM> to continue electric driving of the vehicle <NUM> as much as possible while the engine <NUM> is stopped by consuming the electric power stored in the power storage device <NUM>. The CS mode is a control mode that allows the engine <NUM> to be started more easily than the CD mode, and allows travel of the vehicle <NUM> while maintaining the remaining quantity (SOC) of the power storage device <NUM> within a constant range by charging and discharging the power storage device <NUM> using the engine <NUM>, the first MG <NUM> and the second MG <NUM>.

When, for example, one of the CD mode and the CS mode is set as the control mode, the HV-ECU <NUM> controls the engine <NUM>, the first MG <NUM> and the second MG <NUM>, depending on the set control mode.

When, for example, the travel route is not set (i.e. no destination is set), the HV-ECU <NUM> controls the engine <NUM>, the first MG <NUM> and the second MG <NUM> in accordance with the CD mode until the SOC of the power storage device <NUM> is below a prescribed value. In other words, the HV-ECU <NUM> performs electric traveling using the second MG <NUM> while the engine <NUM> is in a stopped state. Even during selection of the CD mode, when the driving force required for the vehicle <NUM> increases due to, for example, an increased depression amount of the accelerator pedal, the HV-ECU <NUM> starts the engine <NUM> by using the first MG <NUM> and, causes the vehicle <NUM> to travel using the engine <NUM> and the second MG <NUM>.

When the SOC of the power storage device <NUM> falls below the prescribed value, the HV-ECU <NUM> switches from the CD mode to the CS mode, and controls the engine <NUM>, the first MG <NUM> and the second MG <NUM> in accordance with the CS mode. In other words, the HV-ECU <NUM> uses the second MG <NUM> to cause the vehicle <NUM> to travel while causing the first MG <NUM> to generate power using the motive power of the engine <NUM> so as to keep the SOC of the power storage device <NUM> within a prescribed range based on the SOC of the power storage device <NUM> when the control mode is switched. Even during selection of the CS mode, the HV-ECU <NUM> may stop the engine <NUM> and uses the second MG <NUM> to perform electric traveling when, for example, the SOC of the power storage device <NUM> exceeds the prescribed range.

The HV-ECU <NUM> also sets the CS mode as the control mode when, for example, the mode selector switch <NUM> is operated to request the CS mode. In addition, when, for example, the mode selector switch <NUM> is operated to request the CD mode, the HV-ECU <NUM> also sets the CS mode as the control mode, on condition that the SOC of the power storage device <NUM> is the prescribed value or more. Even in the case where the CD mode is selected by operation made on the mode selector switch <NUM>, the HV-ECU <NUM> also switches from the CD mode to the CS mode when the SOC of the power storage device <NUM> is below the prescribed value. In the description below, the prescribed value of the SOC for switching from the CD mode to CS mode may be stated as a switching threshold.

In the present embodiment, the control modes include CD mode, the CS mode, and other control modes. Other control modes include, for example, a mode that prohibits operation of the engine <NUM>. Operating the mode selector switch <NUM> allows selection of one of a plurality of control modes.

In addition, when a travel route is set (when a destination is set), the HV-ECU <NUM> executes travel assist control to switch between the CD mode and the CS mode depending on the travel plan. In the following description, the travel assist control may be referred to as switching control.

Specifically, when a destination is set, the HV-ECU <NUM> sets a travel route from the current position of the vehicle <NUM> to the destination. For example, the HV-ECU <NUM> sets the travel route corresponding to conditions, such as a travel distance, presence or absence of highway use, and presence or absence of traffic congestion. When the travel route is set, the HV-ECU <NUM> sets a travel plan by dividing the travel route from the current position of the vehicle <NUM> to the destination into a plurality of travel sections, and assigning one of the CD mode and the CS mode to each of the travel sections. In the present embodiment, the HV-ECU <NUM> divides the travel route into a plurality of travel sections by using, for example, the nodes on the travel route as separators between the travel sections and using the links as the travel sections.

The HV-ECU <NUM> acquires the updated look-ahead information in the navigation ECU <NUM>, and calculates energy consumption En for each of the travel sections that constitute the travel route based on the acquired look-ahead information. The HV-ECU <NUM> calculates the energy consumption En for each of the travel sections using information included in the look-ahead information, such as slope information, road type information, information about vehicle speed including speed limits, information on the presence or absence of traffic congestion, or the travel distance or the like. The HV-ECU <NUM> may calculate the energy consumption En by using a vehicle weight, or the like, based on the number of occupants of the vehicle <NUM>, in addition to the look-ahead information. The energy consumption En indicates, for example, the energy required for the vehicle <NUM> to travel a target section at a vehicle speed equivalent to the speed limit or a vehicle speed equivalent to the speed in heavy traffic.

For example, the HV-ECU <NUM> assigns one of the CD mode and the CS mode to each of the travel sections such that the SOC of the power storage device <NUM> falls within the prescribed range at the point when the vehicle <NUM> reaches the destination. For example, the prescribed range is the range of SOC based on which complete depletion of the electric power of the power storage device <NUM> can be determined. For example, an upper limit of the prescribed range may be a SOC threshold for switching from the CD mode to the CS mode. Alternatively, the upper limit of the prescribed range may be a predetermined value higher than the threshold, or may be a predetermined value lower than the threshold. A lower limit of the prescribed range is a predetermined value set to be low enough to prevent promotion of deterioration of the power storage device <NUM>.

For example, the HV-ECU <NUM> assigns the CD mode to each of the travel sections when a sum of the energy consumption En for each of the travel sections (hereafter referred to as the total energy consumption) Esum is less than the energy equivalent to the amount of electric power required for the current SOC of the power storage device <NUM> to fall within the prescribed range (hereinafter referred to as remaining energy Er). The threshold indicates an expected value within the prescribed range of SOC when the vehicle <NUM> reaches the destination.

When the total energy consumption Esum is greater than the remaining energy Er, the HV-ECU <NUM> preferentially assigns the CD mode to at least one of the travel sections, and assigns the CS mode to those not assigned with the CD mode.

For example, the HV-ECU <NUM> identifies the travel sections preferentially assigned with the CD mode, among the travel sections, as the CD mode priority section, and assigns the CD mode to the identified travel sections. The CD mode priority sections includes, for example, travel sections such as those in urban areas, residential areas, or narrow streets, where travel noise is required to be suppressed to relatively low levels. Information about whether the travel sections are urban areas, residential areas, or narrow streets is pre-stored in the map information DB.

After the CD mode is assigned to the CD mode priority section, the HV-ECU <NUM> allocates the CD mode to other travel sections in order of lower energy consumption En, and integrates the energy consumption in the allocated travel sections. The HV-ECU <NUM> allocates the CD mode to the travel sections until a value, obtained by adding the sum of the total energy consumed in the travel sections corresponding to the CD mode priority section to the accumulated energy consumption (sum of the energy consumed in the CD mode), becomes greater than the remaining energy Er. The HV-ECU <NUM> stops allocating the CD mode at the point when the sum of the energy consumed in the CD mode becomes greater than the remaining energy Er, and assigns the CS mode to the travel sections not allocated with the CD mode.

In this way, the control modes can be assigned to each of the travel sections to ensure that the SOC of the power storage device <NUM> falls within the prescribed range at the point when the vehicle <NUM> reaches the destination. After the travel plan is set, the HV-ECU <NUM> executes switching control to switch the control modes in accordance with the set travel plan. Therefore, when the operation of the vehicle <NUM> is started, and the vehicle <NUM> passes a node on the travel route, the HV-ECU <NUM> switches to the control mode that is set for the travel section subsequent to the node.

The vehicle <NUM> having the aforementioned configuration may notify the user of how the travel distance, by electric traveling using the electric power of the power storage device <NUM> that is an onboard battery in the case where the switching control is executed for switching the control modes as appropriate in accordance with the travel plan, varies as compared with the travel distance in the case where the switching control is not executed in accordance with the travel plan.

<FIG> shows a display example in the case of notifying the user of the effect of executing the control for switching the control modes as appropriate in accordance with the travel plan.

The navigation ECU <NUM> displays information on the display of the HMI device <NUM> in response to a request from the HV-ECU <NUM>, the information indicating how much the travel distance by electric traveling using the electric power from the power storage device <NUM> is improved, as the effect of executing the control for switching the control modes as appropriate in accordance with the travel plan when, for example, the vehicle <NUM> is traveling, or when the vehicle <NUM> reaches the destination. <FIG> shows an example of displaying on a navigation screen text information indicating that the travel distance, by electric driving using the electric power of the power storage device <NUM>, is improved by Δ Dkm due to, for example, the control mode in cooperation with route guidance (i.e. execution of control for switching the control modes as appropriate in accordance with the travel plan). Such text information is displayed on the HMI device <NUM>, which allows the user to recognize the effect of executing the switching control for switching the control modes as appropriate in accordance with the travel plan. Therefore, at the time of notifying such information to the user, it is required to accurately calculate the travel distance in both the case where the switching control is executed and the case where the switching control is not executed.

However, in the case where, while traveling to the destination, the vehicle <NUM> performs electric traveling during a period of time that is before the switching control is restated after the IG switch is turned off and then turned on, the travel distance during the period of time, which is to be calculated as the travel distance in the case where the switching control is executed unless the IG switch is turned off, may not be counted as the travel distance in the case where the switching control is executed.

<FIG> is an explanatory view about the travel distance by electric traveling using electric power from the power storage device <NUM> when an IG-off period is present. In <FIG>, LN1 represents a change of SOC of the power storage device <NUM> when the switching control is executed. As a result of executing the switching control in accordance with the travel situations, when the vehicle <NUM> passes a node representing a boundary between the travel sections, the control mode corresponding to the travel section subsequent to the node is selected. Therefore, every time the vehicle <NUM> passes the node, the CD mode is switched to the CS mode and the CD mode. After that, when the IG is turned off in the vehicle <NUM> due to refueling, user break, or the like, the switching control is left in a non-executed state after the IG is turned off. Then, when the IG is turned on to depart again, the switching control is restarted when the look-ahead information is acquired. However, since the look-ahead information is acquired every few minutes, there may be a gap between the time of turning on the IG and the time of restarting the switching control. Accordingly, when the CD mode is selected immediately after the IG is turned on, and thereby electric traveling is started using the electric power of the power storage device <NUM>, a distance A of a section that the vehicle <NUM> has traveled before the switching control is restarted is not counted as the travel distance by electric traveling in the case where the switching control is executed. Hence, it may be difficult to accurately calculate the travel distance by electric driving using the electric power of the power storage device <NUM> in the case where the switching control is executed in accordance with the travel situations and the case where the switching control is not executed.

Accordingly, in the present embodiment, the HV-ECU <NUM> operates as follows. Specifically, the HV-ECU <NUM> executes the switching control using external information (look-ahead information) acquired from the outside of the vehicle <NUM> after a predetermined condition (e.g., a condition that the IG is turned on) is established. The HV-ECU <NUM> calculates the travel distance by electric traveling using the electric power of the power storage device <NUM> with the engine <NUM> being stopped in the case where the switching control is not executed (hereinafter referred to as "non-assisted EV travel distance") and the travel distance by electric traveling with the engine <NUM> being stopped in the case where the switching control is executed (hereinafter referred to as "assisted EV travel distance"). When there is an execution history of the switching control before the predetermined condition is met, the HV-ECU <NUM> uses the execution history to calculate the non-assisted EV travel distance and the assisted EV travel distance. Furthermore, the HV-ECU <NUM> calculates the assisted EV travel distance by adding the traveling distance by electric traveling with the engine <NUM> being in the stopped state during a period until the switching control is started after the predetermined condition is established.

In this way, the non-assisted EV travel distance and the assisted EV travel distance are calculated by using the execution history, and the assisted EV travel distance is calculated by adding the travel distance by the electric traveling with the engine <NUM> being in the stopped state during the period until the switching control is started after the predetermined condition is established. Therefore, it is possible to accurately calculate the non-assisted EV travel distance and the assisted EV travel distance.

With reference to <FIG>, an example of control processing executed in the HV-ECU <NUM> will be described below. <FIG> is a flowchart showing an example of processing executed in the HV-ECU <NUM>. A series of processing shown in the flowchart is repeatedly executed at given timing by the HV-ECU <NUM>.

In step (hereinafter stated as "S") <NUM>, the HV-ECU <NUM> determines whether or not the IG is in an ON state. The HV-ECU <NUM> turns on an IG flag when, for example, the user performs startup operation of the control system of the vehicle <NUM> and thereby the IG switch <NUM> is turned on. The HV-ECU <NUM> determines that IG is in the ON state when the IG flag is turned on. Alternatively, the HV-ECU <NUM> may determine that the IG is in the ON state, when, for example, the SMR <NUM> is in a closed state. When it is determined that the IG is in the ON state (YES in S100), the processing is shifted to S102. When it is determined that the IG is not in the ON state (NO in S100), the processing is ended.

In S102, the HV-ECU <NUM> determines whether or not there is any history information (hereinafter referred to as assist implementation history) indicating that the switching control is implemented in accordance with the travel plan. The HV-ECU <NUM> determines that there is an assist implementation history, when, for example, a flag corresponding to the assist implementation history (hereinafter stated as the history flag) is in the ON state. When it is determined that there is an assist implementation history (YES in S102), the processing is shifted to S104. When it is determined that there is no assist implementation history (NO in S102), the processing is shifted to S108.

In S104, the HV-ECU <NUM> refers to the non-assisted EV travel distance and the assisted EV travel distance immediately before the IG is turned off (hereinafter referred to as before IG-off), and a non-assisted battery remaining amount before IG-off, which are stored in memory <NUM>. In this case, the HV-ECU <NUM> sets the non-assisted EV travel distance before IG-off as an initial value of the non-assisted EV travel distance (previous value), sets the assisted EV travel distance before IG-off as an initial value of the assisted EV travel distance (previous value), and sets the value indicating the non-assisted battery remaining amount before IG-off as an initial value of the non-assisted battery remaining amount (previous value).

In S106, the HV-ECU <NUM> calculates the non-assisted EV travel distance and the assisted EV travel distance. When, for example, the non-assisted battery remaining amount is greater than zero, the HV-ECU <NUM> calculates as the non-assisted EV travel distance a value obtained by adding the travel distance by electric driving using the electric power of the power storage device <NUM> of the vehicle <NUM> from the last IG-on to the present time to the non-assisted EV travel distance before IG-off. When, for example, the non-assisted battery remaining amount is equal to or less than zero, the HV-ECU <NUM> calculates as the non-assisted EV travel distance a value obtained by adding the travel distance by electric driving using the electric power of the power storage device <NUM> of the vehicle <NUM> from the last IG-on to the time when the non-assisted battery remaining amount becomes equal to or less than zero to the non-assisted EV travel distance before IG-off. For example, the HV-ECU <NUM> calculates as the assisted EV travel distance a value obtained by adding the travel distance by electric driving using the electric power of the power storage device <NUM> of the vehicle <NUM> from the last IG-on to the present time to the assisted EV travel distance before IG-off. In addition, the HV-ECU <NUM> calculates the non-assisted battery remaining amount by subtracting from the non-assisted battery remaining amount before IG-off the amount consumed by traveling and the amount consumed by auxiliaries in the vehicle <NUM> from the last IG-on to the present time.

In S108, the HV-ECU <NUM> determines whether or not an assist condition is established. The assist condition includes, for example, a condition that a destination is set and a travel route to the destination is set. In addition to the above conditions, the assist condition may include at least one condition out of a condition that no system abnormality occurs in the vehicle <NUM>, a condition that the vehicle <NUM> is traveling on the travel route, and a condition that the SOC of the power storage device <NUM> is higher than the threshold. When it is determined that the assist condition is established (YES in S108), the processing is shifted to S110. When it is determined that the assist condition is not established (NO in S108), the processing is ended.

In S110, the HV-ECU <NUM> determines whether or not look-ahead information received from the navigation ECU <NUM> is updated. The HV-ECU <NUM> determines that the look-ahead information is updated when, for example, various information relating to the look-ahead information, such as prescribed road traffic information, is received. When it is determined that the look-ahead information is updated (YES in S110), the processing is shifted to S112. When it is determined that the look-ahead information is not updated (NO in S110), the processing is returned to S108, and put in a standby state until the look-ahead information is determined to be updated.

In S112, the HV-ECU <NUM> calculates the energy consumption En for each of the travel sections based on information included in the look-ahead information, such as slope information, road type information, and road traffic information on each of the travel sections. Since the method of calculation is as described above, the detailed description thereof is not repeated. The HV-ECU <NUM> also calculates a sum (sum total) of the energy consumption En for each of the travel sections as the total energy consumption Esum.

In S114, the HV-ECU <NUM> determines whether or not the total energy consumption Esum is greater than the remaining energy Er of the power storage device <NUM>, or whether or not there is any assist implementation history. Since the remaining energy Er and the assist implementation history are as described above, the detailed description thereof is not repeated. When the total energy consumption Esum is determined to be greater than the remaining energy Er, or when the assist implementation history is determined to be present (YES in S114), the processing is shifted to S116. When it is determined that the total energy consumption Esum is equal to or less than the remaining energy Er and no assist implementation history is present (NO in S114), the processing is shifted to S128.

In S116, the HV-ECU <NUM> generates a travel plan. More specifically, the HV-ECU <NUM> assigns the CD mode to the travel sections specified as the CD mode priority section. The CD mode priority section is set in advance according to, for example, the type of the road type information (information such as urban areas, highways, and general road) included in the look-ahead information. For example, the travel sections including urban areas and narrow streets are stored in advance as the CD mode priority sections in the HV-ECU <NUM> or the navigation ECU <NUM>, or the travel sections corresponding to the CD mode priority section are received as the road traffic information.

Furthermore, the HV-ECU <NUM> assigns the CD mode to the travel sections other than the CD mode priority sections. The HV-ECU <NUM> sorts the travel sections not specified as the CD mode priority section in order of lower energy consumption En, and assigns the CD mode to the sorted travel sections in order of lower energy consumption En. The HV-ECU <NUM> allocates the CD mode until the sum total of the energy consumption in the travel sections assigned with the CD mode exceeds the remaining energy. The HV-ECU <NUM> stops allocation of the CD mode at the point when the sum total of the energy consumption in the travel sections assigned with the CD mode exceeds the remaining energy.

Furthermore, the HV-ECU <NUM> assigns the CS mode to CD mode non-allocation sections. The HV-ECU <NUM> assigns the CS mode to the travel sections not allocated with the CD mode. A travel plan is generated by assigning one of the CD mode and the CS mode to a plurality of travel sections. Switching the control modes in accordance with the travel plan makes it possible to keep the SOC of the power storage device <NUM> within a prescribed range when the vehicle <NUM> reaches the destination. This makes it possible to use up just enough storage amount of the electric power in the power storage device <NUM>.

In S118, the HV-ECU <NUM> executes switching control of the control modes in accordance with the generated travel plan. At the time, the HV-ECU <NUM> may display on the HMI device <NUM> information indicating, for example, that the switching control is in operation in accordance with the driving plan. When the switching control is executed, the HV-ECU <NUM> shifts the processing to S120.

In S120, the HV-ECU <NUM> determines whether or not there is no assist implementation history. The HV-ECU <NUM> determines that there is no assist implementation history when, for example, the history flag is in an OFF state. When it is determined that there is no assist implementation history (YES in S120), the processing is shifted to S <NUM>.

In S122, the HV-ECU <NUM> sets the non-assisted battery remaining amount. The non-assisted battery remaining amount indicates the amount of electric power available in the power storage device <NUM> during selection of the CS mode when the mode switching control in accordance with the travel plan is not executed. For example, the HV-ECU <NUM> uses the SOC of the power storage device <NUM> to set the non-assisted battery remaining amount. Since the method of calculating the SOC of the power storage device <NUM> is as described above, the detailed description thereof is not repeated. For example, the HV-ECU <NUM> sets the amount of electric power that is equivalent to the value obtained by subtracting a prescribed value from the value indicating the current SOC of the power storage device <NUM> as the non-assisted battery remaining amount. The prescribed value may be, for example, a switching threshold of the SOC for switching from the CD mode to the CS mode, or may be a value obtained by adding or subtracting a predetermined value to or from the switching threshold. Once the non-assisted battery remaining amount is set, the HV-ECU <NUM> shifts the processing to S124.

In S124, the HV-ECU <NUM> sets the history flag to the ON state. Once the history flag is set to the ON state, the HV-ECU <NUM> shifts the processing to S126. When it is determined in S120 that the assist implementation history is present (NO in S122), the processing is shifted to S126.

In S126, the HV-ECU <NUM> calculates the non-assisted EV travel distance and the assisted EV travel distance. Specific methods for calculating the non-assisted EV travel distance and the assisted EV travel distance will be described later with <FIG>.

In S128, the HV-ECU <NUM> determines whether or not a control termination condition is established. The control termination condition includes, for example, a condition that the vehicle <NUM> reaches the destination. The HV-ECU <NUM> determines that the vehicle <NUM> reaches the destination when, for example, the current position of the vehicle <NUM> received from the navigation ECU <NUM> is within a prescribed range including the destination. In addition, the control termination condition includes a condition that the IG is turned off. The control termination condition may further include, for example, a condition that abnormality occurs in the vehicle <NUM>. When it is determined that the control termination condition is established (YES in S128), the processing is shifted to S130. When it is determined that the control termination condition is not established (NO in S128), the processing returns to S108.

In S130, the HV-ECU <NUM> ends the switching control in accordance with the travel plan. The HV-ECU <NUM> sets the history flag to the OFF state when the control termination condition is established due to, for example, establishment of the condition that the vehicle <NUM> reaches the destination. The non-assisted EV travel distance and the assisted EV travel distance are reset to initial values after the information on the effects of executing the switching control shown in <FIG> is displayed on the HMI device <NUM>, for example.

When the vehicle <NUM> does not yet reach the destination and the control termination condition is established due to the IG being turned off, the HV-ECU <NUM> stores a value representing the last non-assisted EV travel distance in the memory <NUM> as the non-assisted EV travel distance before IG-off, and stores a value representing the last assisted EV travel distance in the memory <NUM> as the assisted EV travel distance before IG-off.

Next, an example of the processing to calculate the non-assisted EV travel distance and the assisted EV travel distance implemented in the processing of S126 in <FIG> will be described in detail with reference to <FIG> is a flowchart showing an example of the processing to calculate the non-assisted EV travel distance and the assisted EV travel distance.

In S200, the HV-ECU <NUM> determines whether or not the non-assisted battery remaining amount is greater than zero. When it is determined that the non-assisted battery remaining amount is greater than zero (YES in S200), the processing is shifted to S202. When it is determined that the non-assisted battery remaining amount is equal to or less than zero (NO in S200), the processing is shifted to S206.

In S202, the HV-ECU <NUM> calculates the non-assisted EV travel distance (present value). Specifically, the HV-ECU <NUM> calculates the non-assisted EV travel distance (present value) by adding a movement distance from the time of calculating the previous value to the non-assisted EV travel distance (previous value). The non-assisted EV travel distance (previous value) is the last calculated non-assisted EV travel distance, and its initial value is zero. The HV-ECU <NUM> calculates the movement distance from the time of previous calculation by using the time elapsed from the time of calculating the previous value and the vehicle speed. The HV-ECU <NUM> may use the current vehicle speed detected by the vehicle speed sensor to calculate the movement distance from the time of calculating the previous value, or may calculate the movement distance from the time of calculating the previous value by using an average vehicle speed value during the period from the time of calculating the previous value to the time of calculating the present value.

In S204, the HV-ECU <NUM> calculates the non-assisted battery remaining amount (present value). The HV-ECU <NUM> estimates, as the non-assisted battery remaining amount (present value), the battery remaining amount of the power storage device <NUM> after electric power is consumed by electric driving using the electric power of the power storage device <NUM> in the case where the switching control is not executed since the time of calculating the previous value.

Specifically, the HV-ECU <NUM> calculates the non-assisted battery remaining amount (present value) by subtracting from the non-assisted battery remaining amount (previous value) the amount of electric power corresponding to the amount consumed by traveling during the period from the time of calculating the previous value to the time of calculating the present value and the amount of electric power corresponding to the amount consumed by the auxiliaries during the period. The HV-ECU <NUM> uses the calculated non-assisted battery remaining amount (present time) to update the value of the non-assisted battery remaining amount stored in the memory <NUM>.

For example, the HV-ECU <NUM> calculates the actual energy consumed in the second MG <NUM> (energy consumed by traveling) during the period from the time of calculating the previous value to the time of calculating the present value as the amount consumed by traveling. The HV-ECU <NUM> may calculate the energy consumed by traveling based on, for example, the current and voltage supplied to the second MG <NUM> as the amount consumed by traveling. The HV-ECU <NUM> calculates the energy consumed by traveling by defining a maximum value of the output energy from the second MG <NUM> as a maximum value of the energy consumed by traveling.

For example, the HV-ECU <NUM> calculates the actual energy consumed in the auxiliaries of the vehicle <NUM> (energy consumed by auxiliaries) during the period from the time of calculating the previous value to the time of calculating the present value as the amount consumed by auxiliaries. The auxiliaries of the vehicle <NUM> include, for example, at least one of the air conditioner <NUM>, various cooling fans (for example, electrical devices such as a cooler for the power storage device <NUM>), and various power converters such as DCDC converters. The HV-ECU <NUM> may calculate the energy consumed by auxiliaries based on, for example, the current and voltage supplied to the auxiliaries as the amount consumed by auxiliaries. The non-assisted battery remaining amount (previous value) is the last calculated non-assisted battery remaining amount. Once the non-assisted battery remaining amount (present value) is calculated, the HV-ECU <NUM> shifts the processing to S206.

In S206, the HV-ECU <NUM> determines whether or not the control mode is the CD mode. The HV-ECU <NUM> reads information about the set control mode from the memory <NUM>, and uses the read information to determine whether or not the control mode is the CD mode. When it is determined that the control mode is the CD mode (YES in S206), the processing is shifted to S208. When it is determined that the control mode is not the CD mode (NO in S206), the processing is ended.

In S208, the HV-ECU <NUM> calculates the assisted EV travel distance (present value). Specifically, the HV-ECU <NUM> calculates the assisted EV travel distance (present value) by adding a movement distance from the time of calculating the previous value to the assisted EV travel distance (previous value). The assisted EV travel distance (previous value) is the last calculated assisted EV travel distance, and its initial value is zero. The HV-ECU <NUM> calculates the movement distance from the time of calculating the previous value by using the time elapsed from the time of calculating the previous value and the vehicle speed. Since the method for calculating the movement distance is as described above, the detailed description thereof is not repeated.

Description is given of the operation of the HV-ECU <NUM> mounted on the vehicle <NUM> in the present embodiment based on the structure and flowchart as described in the foregoing.

For example, when the control system of the vehicle <NUM> is started up by the start-up operation of the user, the IG flag is put in the ON state (YES in S100). Accordingly, the HV-ECU <NUM> determines whether or not there is an assist implementation history (S102). When the history flag is in the OFF state, and thereby it is determined that there is no assist implementation history (No in S102), the HV-ECU <NUM> determines whether or not the assist condition is established (S108).

When the destination and the travel route of the vehicle <NUM> are set, it is determined that the assist condition is established (YES in S108). Accordingly, the HV-ECU <NUM> determines whether the look-ahead information is updated (S110). When the navigation ECU <NUM> receives road traffic information and generates the look-ahead information corresponding to the set travel route, and the HV-ECU <NUM> receives the generated look-ahead information from the navigation ECU <NUM>, the HV-ECU <NUM> determines that the look-ahead information is updated (YES in S110). As a result, the HV-ECU <NUM> calculates the energy consumption En in each of a plurality of travel sections that constitute the travel route based on the look-ahead information, and calculates the sum total of the energy consumption En as the total energy consumption Esum (S112).

When the total energy consumption Esum is greater than the remaining energy Er (YES in S114) even though there is no assist implementation history (i.e. the history flag is in the OFF state), the travel plan is generated (S116). In generation of the travel plan, first the CD mode is assigned to the CD mode priority sections, among a plurality of travel sections constituting the travel route. The CD mode is then allocated to the travel sections, out of the travel sections other than the CD mode priority section, in order of lower energy consumption until the total energy consumption in the travel sections allocated with the CD mode exceeds the remaining energy of the power storage device <NUM>. Then, the CS mode is assigned to the travel sections not allocated with the CD mode.

Once the travel plan corresponding to the travel route having all the travel sections assigned with the control modes is generated, the HV-ECU <NUM> executes the switching control of the control modes in accordance with the travel plan (S118).

At this time, since there is no assist implementation history (YES in S120), the HV-ECU <NUM> sets the non-assisted battery remaining amount (S122), sets the history flag to the ON state (S124), and calculates the non-assisted EV travel distance and the assisted EV travel distance (S126).

In other words, when the non-assisted battery remaining amount is greater than zero (YES in S200), the HV-ECU <NUM> calculates the non-assisted EV travel distance (present value) by adding the movement distance since the time of calculating the previous value to the non-assisted EV travel distance (previous value (S202).

Then, the HV-ECU <NUM> calculates the non-assisted battery remaining amount (present value) by subtracting from the non-assisted battery remaining amount (previous value) the amount consumed by traveling and the amount consumed by auxiliaries since the time of calculating the previous value (S204).

In addition, when the CD mode is maintained as the control mode (YES on S206), the HV-ECU <NUM> calculates the assisted EV travel distance (present value) by adding the movement distance since the time of calculating the previous value to the assisted EV travel distance (previous value) (S208). As long as the control termination condition is not established, such as when the vehicle <NUM> has not yet reached the destination (NO in S <NUM>), the HV-ECU <NUM> continuously implements the switching control.

When the control termination condition is established (YES in S128) before the vehicle <NUM> reaches the destination, as in the case where the IG is turned off due to refueling or user breaks, the HV-ECU <NUM> ends the switching control (S130). In this case, the history flag is kept in the ON state because the control termination condition is established by IG-off before reaching the destination. Therefore, when the IG is subsequently turned on (YES in S100), it is determined that there is an assist implementation history (YES in S102). Accordingly, the HV-ECU <NUM> refers to the non-assisted EV travel distance before IG-off and the assisted EV travel distance before IG-off, and the non-assisted battery remaining amount before IG-off stored in the memory <NUM> (S104), and calculates the non-assisted EV travel distance, the assisted EV travel distance, and the non-assisted battery remaining amount (S106). In this case, when the non-assisted battery remaining amount is greater than zero, the HV-ECU <NUM> calculates the non-assisted EV travel distance by adding the movement distance after IG-on to the non-assisted EV travel distance before IG-off. Furthermore, the HV-ECU <NUM> calculates the assisted EV travel distance by adding the movement distance after IG-on to the assisted EV travel distance before IG-off. Accordingly, the non-assisted EV travel distance and the assisted EV distance are calculated by adding the travel distance, by electric traveling using the electric power of the power storage device <NUM> until the switching control is resumed after the IG is temporarily turned off and then turned on, to the non-assisted EV travel distance before IG-off and the assisted EV travel distance before IG-off, respectively.

After that, when the assist condition is established (YES in S108) and the look-ahead information is updated (YES in S110), the HV-ECU <NUM> calculates the non-assisted EV travel distance until the non-assisted battery remaining amount becomes equal to or less than zero, and also calculates the assisted EV travel distance (S126).

As described in the foregoing, in the hybrid vehicle according to the present embodiment, when the IG is temporarily turned off and then turned on while the switching control is in operation, the non-assisted EV travel distance and the assisted EV travel distance are calculated using the execution history (non-assisted EV travel distance before IG-off, non-assisted battery remaining amount before IG-off, and assisted EV travel distance before IG-off), and also at least the assisted EV travel distance is calculated by adding the travel distance by electric traveling with the engine <NUM> being in the stopped state during a period until the switching control is started after IG-on. Hence, it is possible to accurately calculate the non-assisted EV travel distance and the assisted EV travel distance. Therefore, it is possible to provide the hybrid vehicle that accurately calculates the travel distance by electric driving using electric power from an onboard battery in the case where switching control is executed according to the traveling situations and in the case where the switching control is not executed.

Hereinafter, modifications will be described.

In the embodiment, the vehicle <NUM> has been described, for example, as a series parallel hybrid vehicle. However, as long as the CD mode and the CS mode can be set, the vehicle <NUM> may be any hybrid vehicle, such as a series hybrid vehicle, other than the series parallel hybrid vehicle.

Furthermore, in the embodiment, the remaining energy Er has been described as the energy equivalent to the amount of electric power taken required the current SOC of the power storage device <NUM> to be within the prescribed range. However, the remaining energy Er may be obtained by adding a certain margin to that energy.

Furthermore, in the embodiment described in the foregoing, the HV-ECU <NUM> and the navigation ECU <NUM> each execute their prescribed processing, and exchange various information to operate in cooperation. However, a single ECU having the functions of the HV-ECU <NUM> and the functions of the navigation ECU <NUM> may execute the prescribed processing.

Furthermore, in the embodiment described in the foregoing, the information about switching control as shown in <FIG> has been described as being displayed on the HMI device <NUM>. However, the information may be displayed on the display device of a mobile terminal owned by the user instead of or in addition to the HMI device <NUM>.

<FIG> shows an example of the configuration of a hybrid vehicle in a modification. The vehicle <NUM> shown in <FIG> is different from the vehicle <NUM> shown in <FIG> in that a communication device <NUM> is provided. The communication device <NUM> can communicate with at least one of a mobile terminal <NUM> owned by the user and a server <NUM> provided outside the vehicle <NUM>. The configuration of the vehicle <NUM> shown in <FIG> is similar to the configuration of the vehicle <NUM> shown in <FIG> except for the communication device <NUM>. Therefore, the detailed description is not repeated.

As shown in <FIG>, the vehicle <NUM> further includes the communication device <NUM>. The communication device <NUM> is configured to be communicable with at least one of the mobile terminal <NUM> owned by the user of the vehicle <NUM> and a mobile terminal <NUM> via the server <NUM> provided outside the vehicle <NUM>.

The communication device <NUM> and the mobile terminal <NUM> may be connected so as to be communicable through prescribed near-range wireless communication by, for example, executing pairing processing in advance. The communication device <NUM> and the mobile terminal <NUM> may be connected so as to be communicable through wireless communication such as a wireless local area network (LAN) via a base station not illustrated. Alternatively, the communication device <NUM> and the mobile terminal <NUM> may be directly connected through wired connection.

The mobile terminal <NUM> is provided with a display unit <NUM>. The display unit <NUM> is configured to be able to display information received from the communication device <NUM> in a prescribed format. The HV-ECU <NUM> may transmit information about the switching control to the mobile terminal <NUM> via the communication device <NUM>. The mobile terminal <NUM> may display the information received from the communication device <NUM> on the display unit <NUM>. This configuration also enables the user to recognize the information about the switching control, such as the effect of executing the switching control. When the HV-ECU <NUM> transmits the information about the switching control to the mobile terminal <NUM> via the communication device <NUM>, the HV-ECU <NUM> may not display the information received from the communication device <NUM> on the HMI device <NUM>.

The communication device <NUM> and the server <NUM> may also be connected so as to be communicable through, for example, wireless communication such as wireless LAN via a base station not illustrated. The server <NUM> and the mobile terminal <NUM> may also be connected so as to be communicable through, for example, wireless communication such as wireless LAN via a base station not illustrated.

The mobile terminal <NUM> is provided with a display unit <NUM>. The display unit <NUM> is configured to be able to display information received from the communication device <NUM> via the server <NUM> in a prescribed format. The HV-ECU <NUM> may transmit information about the switching control to the mobile terminal <NUM> via the communication device <NUM> and the server <NUM>. The mobile terminal <NUM> may display the information received from the server <NUM> on the display unit <NUM>. This configuration also enable the user to recognize the information about the switching control, such as the effect of executing the switching control.

In the embodiment described in the foregoing, in the case where the control termination condition is established due to the IG being turned off before the vehicle <NUM> reaches the destination, and the switching control is ended, the non-assisted EV travel distance before IG-off, the assisted EV travel distance before IG-off, and the non-assisted battery remaining amount before IG-off are stored in the memory <NUM> while the history flag is kept in the ON state, and the travel distance by electric traveling until the switching control is restarted after the IG is turned on is added to both the travel distances so as to calculate the non-assisted EV travel distance and the assisted EV travel distance. However, the non-assisted EV travel distance and the assisted EV travel distance may be calculated as below.

Specifically, in the case where the control termination condition is established due to the switching control being temporarily interrupted before the vehicle <NUM> reaches the destination, and then the switching control returns from the interrupted state, the travel distance by the electric traveling in the period in the interrupted state and the travel distance by the electric traveling in the period until the switching control is restarted after the switching control is put in the interrupted state may be calculated, and the calculated travel distances may be added to calculate the assisted EV travel distance.

<FIG> is a flowchart showing an example of the processing executed in the HV-ECU <NUM> in a modification.

The processing shown in the flowchart in <FIG> is different from the processing shown in the flowchart in <FIG> in the following points. That is, the processing of S104 is omitted, processing of S300 is executed instead of the processing of S108, and processing of S302, processing of S304, processing of S306, and processing of S308 are executed in place of the processing of S128 and the processing of S130. The processing other than the above-stated processing are the same as that shown in the flowchart in <FIG> and designated by the same step number, unless otherwise described below. Therefore, the detailed description thereof is not repeated.

When it is determined that there is no assist implementation history (NO in S102), the processing is shifted to S300. Alternatively, when it is determined that there is an assist implementation history (YES in S102), and the non-assisted EV travel distance and the assisted EV travel distance are calculated (S106), the processing is shifted to S300.

In S300, the HV-ECU <NUM> determines whether or not the assist condition is established. Since the assist condition is as described above, the detailed description thereof is not repeated. When it is determined that the assist condition is established (YES in S300), the processing is shifted to S110. When it is determined that the assist condition is not established (NO in S300), the processing is shifted to S302. Alternatively, when the non-assisted EV travel distance and the assisted EV travel distance are calculated in S126, the processing is shifted to S302.

In S302, the HV-ECU <NUM> determines whether or not the control termination condition is established. Since the control termination condition is as described above, the detailed description thereof is not repeated. When it is determined that the control termination condition is established (YES in S302), the processing is shifted to S304. When it is determined that the control termination condition is not established (NO in S302), the processing is shifted to S306.

In S304, the HV-ECU <NUM> ends the switching control in accordance with the travel plan. For example, the HV-ECU <NUM> sets the history flag to the OFF state. In addition, the non-assisted EV travel distance and the assisted EV travel distance are reset to initial values after the information on the effects of executing the switching control shown in <FIG> is displayed on the HMI device <NUM>, for example.

In S306, the HV-ECU <NUM> determines whether or not a control interruption condition is established. The control interruption condition includes, for example, a condition that at least one condition is established out of a condition that abnormal temperature of the power storage device <NUM> occurs, a condition that electric power of the power storage device <NUM> is depleted, a condition that the vehicle <NUM> is out of the travel route, and a condition that the engine <NUM> is started in the CD mode.

The HV-ECU <NUM> determines that the abnormal temperature has occurred in the power storage device <NUM> when, for example, the power storage device <NUM> is in the state of high temperature higher than a threshold. In addition, the HV-ECU <NUM> determines that electric power of the power storage device <NUM> is depleted when, for example, the SOC of the power storage device <NUM> is equal to or less than a threshold (for example, a value indicating a lower limit value of the SOC). In addition, the HV-ECU <NUM> determines that the vehicle <NUM> is out of the travel route when the current position of the vehicle <NUM> is moving on a route that is different from the set travel route (or a route distanced by a prescribed distance or more). In addition, the HV-ECU <NUM> determines that the engine <NUM> is started in the CD mode when the condition for starting the engine <NUM> is established (or when the engine speed is equal to or more than a threshold) during selection of the CD mode. The condition for starting the engine <NUM> may include, for example, a condition that the accelerator operation amount is equal to or more than a threshold.

When it is determined that the control interruption condition is established (YES in S306), the processing is shifted to S308. When it is determined that the control interruption condition is not established (NO in S306), the processing returns to S300.

In S308, the HV-ECU <NUM> sets the switching control to the interrupted state. In this case, the HV-ECU <NUM> continues to select the CD mode. When the information indicating that the switching control is in operation in accordance with the travel plan is being displayed on the HMI device <NUM>, the HV-ECU <NUM> may put the HMI device in a non-display state. When the switching control is set to the interrupted state, the HV-ECU <NUM> returns the processing to S102.

Description is given of the operation of the HV-ECU <NUM> in the modification based on the structure and flowchart as described in the foregoing.

For example, when the control system of the vehicle <NUM> is started up by the start-up operation of the user, the IG flag is put in the ON state (YES in S100). Accordingly, the HV-ECU <NUM> determines whether or not there is an assist implementation history (S102). When the history flag is in the OFF state, and thereby it is determined that there is no assist implementation history (No in S102), then the HV-ECU <NUM> determines whether or not the assist condition is established (S300).

When the destination and the travel route of the vehicle <NUM> are set, it is determined that the assist condition is established (YES in S300). Accordingly, the HV-ECU <NUM> determines whether the look-ahead information is updated (S110). When the navigation ECU <NUM> receives road traffic information, and generates the look-ahead information corresponding to the set travel route, and the HV-ECU <NUM> receives the generated look-ahead information from the navigation ECU <NUM>, the HV-ECU <NUM> determines that the look-ahead information is updated (YES in S110). As a result, the HV-ECU <NUM> calculates the energy consumption En in each of a plurality of travel sections that constitute the travel route based on the look-ahead information, and calculates the sum total of the energy consumption En as the total energy consumption Esum (S112).

When the total energy consumption Esum is greater than the remaining energy Er (YES in S114) even though there is no assist implementation history, the travel plan is generated (S116), and the switching control of the control modes is executed in accordance with the travel plan (S118).

In other words, when the non-assisted battery remaining amount is greater than zero (YES in S200), the HV-ECU <NUM> calculates the non-assisted EV travel distance (present value) by adding the movement distance since the time of calculating the previous value to the non-assisted EV travel distance (previous value) (S202).

Then, the HV-ECU <NUM> calculates the non-assisted battery remaining amount (present value) by subtracting the amount consumed by traveling and the amount consumed by auxiliaries since the time of calculating the previous value from the non-assisted battery remaining amount (previous value) (S204).

In addition, when the CD mode is maintained as the control mode (YES on S206), the HV-ECU <NUM> calculates the assisted EV travel distance (present value) by adding the movement distance since the time of calculating the previous value to the assisted EV travel distance (previous value) (S208). When the control termination condition is not established, such as when the vehicle <NUM> does not yet reach the destination (NO in S <NUM>), the HV-ECU <NUM> continuously implement the switching control.

When the abnormal temperature occurs in the power storage device <NUM> before the vehicle reaches the destination (No in S302, YES in S306), the HV-ECU <NUM> sets the switching control to the interrupted state (S308). At this time, the information indicating that the switching control is in operation is not displayed on the HMI device <NUM>. Meanwhile, since the history flag is kept in the ON state, it is determined that there is an assist implementation history (YES in S102). Therefore, during the period until the assist condition is established (No in S300), the non-assisted EV travel distance and the assisted EV travel distance are continuously calculated (S106). Once the abnormal temperature of the power storage device <NUM> is eliminated, the control interruption condition is no longer established (NO in S306), and the support condition is again established (YES in S300). Hence, the look-ahead information is updated (YES in S110), and the switching control is restarted (S118). In this case, since the non-assisted EV travel distance and the assisted EV travel distance are continuously calculated (S126), the travel distance by electric driving using the electric power of the power storage device <NUM> during the period that the switching control is interrupted, and the travel distance by electric drive using the electric power of the power storage device <NUM> during the period until the switching control is started after the control interruption condition is not established are added to calculate the non-assisted EV travel distance and the assisted EV travel distance, respectively.

Thus, after the switching control is returned from a temporarily interrupted state, the non-assisted EV travel distance and the assisted EV travel distance are calculated by using the execution history of the switching control, and also the travel distance by electric traveling with the engine <NUM> being in the stopped state during the period until the switching control is started after the switching control is returned is added to calculate at least the assisted EV travel distance. Hence, it is possible to accurately calculate the non-assisted EV travel distance and the assisted EV travel distance.

Claim 1:
A hybrid vehicle, comprising:
a second electric motor generator (<NUM>) and an engine (<NUM>) configured to generate drive force for the vehicle;
a power storage device (<NUM>) configured to supply electric power to the second electric motor generator (<NUM>);
a first electric motor generator (<NUM>) configured to generate electric power generated to charge the power storage device (<NUM>) by receiving motive power from the engine; and
a controller (<NUM>) configured to control the engine (<NUM>) and the second electric motor generator (<NUM>) in accordance with one of a plurality of control modes, wherein:
the control modes include a charge depleting (CD) mode and a charge sustaining (CS) mode;
the controller is configured to
execute switching control for switching the control modes in accordance with a travel plan by using external information acquired from outside of the vehicle after a predetermined condition is established, the travel plan including a travel route of the vehicle to a destination, the travel route including a plurality of sections each assigned with one of the CD mode and the CS mode,
calculate, when there is an execution history of the switching control prior to establishment of the predetermined condition, a first travel distance and a second travel distance by using the execution history, the first travel distance being a distance by electric traveling using electric power from the power storage device (<NUM>) with the engine (<NUM>) being in a stopped state when the switching control is not executed, the second travel distance being a distance by the electric traveling with the engine (<NUM>) being in the stopped state when the switching control is executed, and
calculate the second travel distance by adding a travel distance by the electric traveling with the engine (<NUM>) being in the stopped state during a period until the switching control is restarted after the predetermined condition is established.