Patent Description:
Conventionally, as a hybrid vehicle of this type, there has been proposed a vehicle that restricts at least one output out of an output of an electric motor and an output of an internal combustion engine when change in a parameter, which corresponds to fuel consumption consumed by the internal combustion engine from the time of external charging of the battery, reaches a specified value (see, for example, <CIT>). In the hybrid vehicle, when change in the parameter reaches the specified value, at least one output out of the output of the electric motor and the output of the internal combustion engine is restricted so as to encourage a driver to conduct external charging and to promote traveling independent of the internal combustion engine. Accordingly, it becomes possible to sufficiently implement an effect of suppressing atmospheric contamination, which is an original purpose of the electric vehicles, while reserving a capacity of the internal combustion engine to allow traveling in emergency situations.

Further background is disclosed in <CIT> "Charging and Discharging Control Apparatus and Electric Motor Vehicle" and <CIT> "Methods and Systems for Monitoring a Vehicle's Energy Source".

However, since the aforementioned hybrid vehicle uses the parameter corresponding to fuel consumption consumed by the internal combustion engine from the time of external charging of the battery, it is sometimes difficult to properly determine how much electric travel, which does not involve operation of the internal combustion engine, is being performed or how appropriately the external charging is being conducted.

The present invention provides an electronic control unit configured to be included in a hybrid vehicle as specified in claims <NUM> to <NUM>.

Now, a mode for carrying out the present invention will be described in detail based on an embodiment.

<FIG> is a block diagram illustrating an outlined configuration of a hybrid vehicle <NUM> as an embodiment of the present invention. The hybrid vehicle <NUM> of the embodiment includes, as illustrated in the drawing, an engine <NUM>, a planetary gear <NUM>, motors MG1, MG2, inverters <NUM>, <NUM>, a battery <NUM>, a battery charger <NUM>, and a hybrid electronic control unit <NUM> (hereinafter referred to as "HVECU").

The engine <NUM> is configured as an internal combustion engine that outputs motive power by using fuel such as gasoline and gas oil from a fuel tank <NUM>. The operation of the engine <NUM> is controlled by an engine electronic control unit <NUM> (hereinafter referred to as "engine ECU").

Although not illustrated, the engine ECU <NUM> is configured as a microprocessor having a CPU as a main component. The engine ECU <NUM> includes, in addition to the CPU, a ROM that stores processing programs, a RAM that temporarily stores data, input and output ports, and a communication port. The engine ECU <NUM> receives, through the input port, signals from various sensors needed for operation control of the engine <NUM>, the signals including, for example, a crank angle θcr from a crank position sensor <NUM> that detects a rotational position of a crankshaft <NUM> of the engine <NUM>. The engine ECU <NUM> outputs various control signals for operation control of the engine <NUM> through the output port. The engine ECU <NUM> is connected with the HVECU <NUM> through the communication port. The engine ECU <NUM> calculates a speed Ne of the engine <NUM> based on the crank angle θcr from the crank position sensor <NUM>.

The planetary gear <NUM> is configured as a single pinion-type planetary gear mechanism. The planetary gear <NUM> has a sun gear connected to a rotator of the motor MG1. The planetary gear <NUM> has a ring gear connected to a driving shaft <NUM> coupled with wheels 38a, 38b through a differential gear <NUM>. The planetary gear <NUM> has a carrier connected to the crankshaft <NUM> of the engine <NUM> through a damper <NUM>.

The motor MG1, which is configured as a synchronous generator-motor for example, has a rotator connected to the sun gear of the planetary gear <NUM> as stated before. The motor MG2, which is configured as a synchronous generator-motor for example, has a rotator connected to the driving shaft <NUM>. The inverters <NUM>, <NUM> are connected with the battery <NUM> through an electric power line <NUM>. The motors MG1, MG2 are rotationally driven when a motor electronic control unit <NUM> (hereinafter referred to as "motor ECU") performs switching control of a plurality of unillustrated switching elements of the inverters <NUM>, <NUM>.

Although not illustrated, the motor ECU <NUM> is configured as a microprocessor having a CPU as a main component. The motor ECU <NUM> includes, in addition to the CPU, a ROM that stores processing programs, a RAM that temporarily stores data, input and output ports, and a communication port. The motor ECU <NUM> receives, through the input port, signals from various sensors needed for controlling the operation of the motors MG1, MG2, the signals including, for example, rotational positions θm1, θm2 from rotational position detection sensors <NUM>, <NUM> that detect rotational positions of the rotators of the motors MG1, MG2. The motor ECU <NUM> outputs, through the output port, signals such as a switching control signal to a plurality of unillustrated switching elements of the inverters <NUM>, <NUM>. The motor ECU <NUM> is connected with the HVECU <NUM> through the communication port. The motor ECU <NUM> calculates the numbers of rotations Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2 of the rotators of the motors MG1, MG2 from the rotational position detection sensors <NUM>, <NUM>.

The battery <NUM> is configured, for example, as a lithium-ion secondary battery or a nickel-hydrogen secondary battery. The battery <NUM> is connected with the inverters <NUM>, <NUM> through the electric power line <NUM> as stated before. The battery <NUM> is managed by a battery electronic control unit (hereinafter referred to as "battery ECU") <NUM>.

Although not illustrated, the battery ECU <NUM> is configured as a microprocessor having a CPU as a main component. The battery ECU <NUM> includes, in addition to the CPU, a ROM that stores processing programs, a RAM that temporarily stores data, input and output ports, and a communication port. The battery ECU <NUM> receives signals from various sensors needed to manage the battery <NUM> through the input port. Examples of the signals include a battery voltage Vb from a voltage sensor 51a disposed between terminals of the battery <NUM>, and a battery current Ib from a current sensor 51b attached to an output terminal of the battery <NUM>. The battery ECU <NUM> is connected with the HVECU <NUM> through the communication port. The battery ECU <NUM> calculates a state of charge SOC based on an integrated value of the battery current Ib from the current sensor 51b. The state of charge SOC refers to a ratio of capacity of electric power dischargeable from the battery <NUM> to the total capacity of the battery <NUM>.

The battery charger <NUM> is connected to the electric power line <NUM> and is configured to be able to perform external charging of the battery <NUM> with electric power from an external power supply <NUM>, such as a household power supply and an industrial power supply, when a power supply plug <NUM> of the battery charger <NUM> is connected to the external power supply <NUM> at a charging point such as a residence and a charging station.

A navigation device <NUM> includes a main body incorporating a control unit, the control unit having a storage medium such as a hard disk, input and output ports, a communication port and the like, the storage medium storing information such as map information. The navigation device <NUM> also includes a GPS antenna configured to receive information about a present location of the vehicle, and a touch-sensitive display configured to display a variety of information, such as the information about the present location of the vehicle and a travel route to a destination and to enable an operator to input various instructions. Here, the map information is stored as a database including service information (such as sightseeing information, parking area information, and charging station information) and traffic information on each preset traveling section (such as sections between signaling devices and between junctions). The traffic information includes distance information, width information, area information (urban areas and suburban areas), classification information (general roads and highways), slope information, legal speeds, and the number of signaling devices. As the service information, a residential parking space and desired locations can be registered as registered locations. When a destination is set by the operator, the navigation device <NUM> searches for a travel route from the present location of the vehicle to the destination based on the map information, the present location of the vehicle and the destination, and outputs the searched travel route on the display to provide route guidance. The navigation device <NUM> also calculates route information (such as a remaining distance Ln to the destination, and a direction Dn of the destination) for the travel route.

Although not illustrated, the HVECU <NUM> is configured as a microprocessor having a CPU as a main component. The electronic control unit <NUM> includes, in addition to the CPU, a ROM that stores processing programs, a RAM that temporarily stores data, a flash memory <NUM>, input and output ports, and a communication port. The HVECU <NUM> receives signals from various sensors through the input port. Examples of the signals input into the HVECU <NUM> include an ignition signal from an ignition switch <NUM>, a shift position SP from a shift position sensor <NUM>, an accelerator opening Acc from an accelerator pedal position sensor <NUM>, a brake pedal position BP from a brake pedal position sensor <NUM>, and a vehicle speed V from a vehicle speed sensor <NUM>. The examples of the signals also include a fuel quantity Qf from a fuel gauge 25a attached to the fuel tank <NUM>, a connection signal SWC from a connection switch <NUM> attached to the power supply plug <NUM> so as to determine whether or not the power supply plug <NUM> is connected to the external power supply <NUM>. The HVECU <NUM> outputs signals such as a control signal to the battery charger <NUM> through the output port. As described before, the HVECU <NUM> is connected with the engine ECU <NUM>, the motor ECU <NUM>, and the battery ECU <NUM> through the communication port. When fuel is supplied to the fuel tank <NUM>, the HVECU <NUM> calculates a fuel supply quantity Qin based on the fuel quantity Qf from the fuel gauge 25a.

In the thus-configured hybrid vehicle <NUM> of the embodiment, hybrid traveling (HV traveling) or electric traveling (EV traveling) is performed in a Charge Depleting (CD) mode or a Charge Sustaining (CS) mode. Here, the CD mode is a mode that prioritizes the EV traveling more than the CS mode. The HV traveling is a mode of traveling involving operation of the engine <NUM>. The EV traveling is a mode of traveling without involving operation of the engine <NUM>.

In the embodiment, the HVECU <NUM> controls the battery charger <NUM> such that the battery <NUM> is charged with electric power from the external power supply <NUM> when the power supply plug <NUM> is connected to the external power supply <NUM> while the vehicle is parked in a charging point such as a residence and a charging station with a system of the vehicle being turned off (the system being stopped). If the state of charge SOC of the battery <NUM> is larger than a threshold Shv1 (that is a value such as <NUM>%, <NUM>%, and <NUM>%) when the system is turned on (the system is started), the vehicle travels in the CD mode until the state of charge SOC of the battery <NUM> reaches a thresholds Shv2 (that is a value such as <NUM>%, <NUM>%, and <NUM>%) or less. After the state of charge SOC of the battery <NUM> reaches the threshold Shv2 or less, the vehicle travels in the CS mode until the system is turned off. When the state of charge SOC of the battery <NUM> is equal to or less the threshold Shv when the system is turned on, the vehicle travels in the CS mode until the system is turned off.

A description is now given of operation of the thus-configured hybrid vehicle <NUM> of the embodiment, and particularly the operation of calculating and storing a charging frequency Fchg used as a utilization index of charging (external charging) of the battery <NUM> by the battery charger <NUM>. <FIG> is a flowchart illustrating one example of a charging date storage processing routine executed by the HVECU <NUM>. <FIG> is a flowchart illustrating one example of a charging frequency calculation processing routine executed by the HVECU <NUM>. In the embodiment, the charging date storage processing routine and the charging frequency calculation processing routine are executed when the vehicle is parked and the system is turned off (system is stopped), and then the system is turned on (system is started). A detailed description will be provided in sequence.

When the charging date storage processing routine is executed, the HVECU <NUM> first acquires a parking position from the navigation device <NUM> (step S100) and determines whether the acquired parking location is a residential parking space or a charging station (step S110). When the parking location is not the residential parking space nor the charging station, it is determined that the vehicle is parked at a location where external charging is not available, and the present routine is ended. When the parking location is the residential parking space or the charging station, it is determined that the vehicle is parked in the location where external charging is available, and a present date is stored in a parking date storage area predetermined in the flash memory <NUM> (step S120). Then, it is determined whether or not external charging was performed (step S130). Whether or not the external charging was performed can be determined based on a connection signal SWC from the connection switch <NUM> indicative of connection between the power supply plug <NUM> of the battery charger <NUM> and the external power supply <NUM> and based on whether or not the state of charge SOC of the battery <NUM> was increased from the SOC at the time when the system was turned off. When external charging was performed, the pertinent date is stored in the charging date storage area predetermined in the flash memory <NUM> (step S140), and the present routine is ended. When the external charging was not performed, the present routine is ended without the date being stored.

When the charging frequency calculation processing routine is executed, the HVECU <NUM> first searches for dates within a predetermined period (for example, a period of past <NUM> days, and a period of past <NUM> trips) from the parking date storage area of the flash memory <NUM>, and counts the number of the dates as the number of opportunities Copp (step S200). Next, the HVECU <NUM> searches for dates within the same period (predetermined period) from the charging date storage area of the flash memory <NUM>, and counts the number of dates as the number of times of charging Cchg (step S210). The HVECU <NUM> then divides the number of times of charging Cchg by the number of opportunities Copp to calculate a charging frequency Fchg, and stores the charging frequency Fchg in a prescribed area of the flash memory <NUM> (step S220). Since the charging frequency Fchg is a ratio of the number of times of external charging performed to the number of opportunities where the external charging is available in the predetermined period, it can be determined that as the ratio is larger, utilization of the external charging is promoted more. Accordingly, the ratio can be used as an index that can offer more accurate determination regarding the utilization status of the external charging. Once the charging frequency Fchg is calculated and stored in this way, the charging frequency Fchg is compared with a threshold Fref (step S230). When the charging frequency Fchg is equal to or larger than the threshold Fref, it is determined that the utilization status of the external charging is sufficient and the present routine is ended. When the charging frequency Fchg is less than the threshold Fref, it is determined that the utilization status of the external charging is not sufficient. Accordingly, some processing is conducted to promote the external charging, such as notification processing to perform processing such as announcement of a message "Use an external power supply to charge the vehicle", and function restriction processing to perform processing such as restricting the torque necessary for traveling (step S240), and the present routine is ended.

In the hybrid vehicle <NUM> in the embodiment described in the foregoing, the number of opportunities Copp and the number of times of charging Cchg are obtained, the number of opportunities Copp being counted as the number of opportunities where external charging of a vehicle parked in a residential parking space or a charging station is available in a predetermined period, the number of times of charging Cchg being counted as the number of times of the external charging performed in the opportunities where the external charging is available in the same predetermined period. The number of times of charging Cchg is then divided by the number of opportunities Copp to calculate and store the charging frequency Fchg. Since the charging frequency Fchg is a ratio of the number of times that the external charging was performed to the number of opportunities where the external charging is available in the predetermined period, the ratio is used as an index that can offer more accurate determination regarding the utilization status of the external charging. As a result, various processing to promote external charging can be executed more properly.

In the hybrid vehicle <NUM> of the embodiment, the residential parking space and the charging station are used as a parking location where the number of opportunities Copp is counted. However, a location to count the number of opportunities Copp may be a charging station within a specified distance (such as <NUM> or <NUM>) from the residential parking space and the residence, or may be a charging station registered in advance as a regular charging location.

The hybrid vehicle <NUM> of the embodiment includes the battery charger <NUM> that charges the battery <NUM> with the power supply plug <NUM> being connected to the external power supply <NUM>. However, the hybrid vehicle <NUM> may include a battery charger that charges the battery <NUM> by receiving electric power from the external power supply <NUM> in a non-contact manner.

The hybrid vehicle <NUM> of the embodiment is configured such that the engine <NUM>, the motor MG1, and the driving shaft <NUM> are connected to the planetary gear <NUM>, and the driving shaft <NUM> is connected to the motor MG2. Like a hybrid vehicle <NUM> in a modification illustrated in <FIG>, the present invention may be configured such that a driving shaft <NUM> coupled with wheels 38a, 38b is connected to a motor MG through a transmission <NUM>, and a rotating shaft of the motor MG is connected to an engine <NUM> through a clutch <NUM>. In this case, motive power from the engine <NUM> may be output to the driving shaft <NUM> through the rotating shaft of the motor MG and the transmission <NUM>, and motive power from the motor MG may be output to the driving shaft through the transmission <NUM>. The present invention may also be configured as so-called a series-hybrid vehicle. That is, the present invention may be a hybrid vehicle of any configuration as long as the hybrid vehicle includes an engine, a motor, a battery, and a battery charger connected to an external power supply to charge the battery.

Correspondence relation between the main elements of the embodiment and the main elements of the present invention described in Summary of the Invention will be described. In the embodiment, the engine <NUM> corresponds to "the engine", the fuel tank <NUM> corresponds to "the fuel tank", the motor MG2 corresponds to "the motor", the battery <NUM> corresponds to "the battery", the battery charger <NUM> corresponds to "the battery charger", and the HVECU <NUM> that executes the charging date storage processing routine in <FIG> and the charging frequency calculation processing routine in <FIG> corresponds to "the control unit".

Since the embodiment is one example for specific description of the mode for carrying out the present invention described in Summary of the Invention, the correspondence relation between the main elements of the embodiment and the main elements of the present invention described in Summary of the Invention is not intended to limit the elements of the invention described in Summary of the Invention. More specifically, the invention disclosed in Summary of the Invention should be interpreted based on the description therein, and the embodiment is merely a specific example of the invention disclosed in Summary of the Invention.

Although the mode for carrying out the present invention has been described using the embodiment, the present invention is not limited in any manner to the embodiment disclosed, but is defined by the claims. It should naturally be understood that the present invention can be carried out in various modes without departing from the scope of the present invention.

The present invention is applicable in the fields such as manufacturing of the hybrid vehicle.

The number of opportunities where external charging of a vehicle parked in a residential parking space or a charging station in a predetermined period is available is counted as the number of opportunities (S200), and the number of times of the external charging performed in the opportunities in the same predetermined period is counted as the number of times of charging (S210). The number of times of charging is then divided by the number of opportunities to calculate and store a charging frequency (S220). Since the charging frequency is a ratio of the number of times that the external charging was performed to the number of opportunities where the external charging is available in the predetermined period, the ratio is used as an index that can offer more accurate determination regarding an external charging utilization status. As a result, various processing to promote external charging can be executed more properly.

Claim 1:
An electronic control unit (<NUM>) configured to be included in a hybrid vehicle, and further configured to
i) count the number of times of charging opportunities that the hybrid vehicle is in a state where external charging is available in a predetermined period, as the number of times of opportunities,
ii) count the number of times of the external charging that the vehicle performed in the predetermined period, as the number of times of charging, and
iii) calculate and store a ratio of the number of times of charging to the number of times of opportunities, as a charging frequency.