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> "System and Method of Converting a Standard Hybrid Vehicle into a Plug-In Hybrid Electric Vehicle (PHEV)" and <CIT> "Hybrid Vehicle, Informing Method for Hybrid Vehicle, and Computer Readable Recording Medium Having Recorded thereon Program for Causing Computer to Execute the Informing Method".

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 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 (hereinafter referred to as "HVECU") <NUM>.

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 (hereinafter referred to as "engine ECU") <NUM>.

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, input of 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 a pair of driving 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 (hereinafter referred to as "motor ECU") <NUM> 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, input of signal 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 input of 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 as a battery that can 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.

Although not illustrated, the HVECU <NUM> is configured as a microprocessor having a CPU as a main component. The HVECU <NUM> includes, in addition to the CPU, a ROM that stores processing programs, a RAM that temporarily stores data, a flash memory, 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 oil is supplied to the fuel tank <NUM>, the HVECU <NUM> calculates an 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 than 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 more particularly operation of calculating and storing a utilization index IDX of charging (external charging) of the battery <NUM> by the battery charger <NUM> based on a ratio of an EV traveling utilization level to an HV traveling utilization level or a total traveling utilization level. <FIG> is a flowchart illustrating one example of a utilization index calculation processing routine executed by the HVECU <NUM>. The routine is executed in predetermined startup timing, such as when the system is turned on (started), when the system is turned off (stopped), when charging of the battery <NUM> is completed with the power supply plug <NUM> being connected to the external power supply <NUM>, and when oil is supplied to the fuel tank <NUM>. In the following description, the present routine is assumed to be executed when the system is turned on (started).

When the utilization index calculation processing routine is executed, the HVECU <NUM> first executes processing of inputting data that reflects a vehicle utilization status necessary to calculate a utilization index IDX in a predetermined plurality of trips (step S <NUM>). Since the HV traveling utilization level, the total traveling utilization level, and the EV traveling utilization level are based on the utilization status of the vehicle, the data reflecting the vehicle utilization status is input. The data reflecting the vehicle utilization status is defined as data from the time of turning on the system in a previous trip to the time of turning on the system in a present trip. Examples of the data include presence of charging of the battery <NUM> by the battery charger <NUM>, charging time (battery charger connection time) with the power supply plug <NUM> of the battery charger <NUM> being connected to the external power supply <NUM>, and a charge amount of the battery <NUM> by the battery charger <NUM>. Examples of the data also include an fuel supply quantity, fuel quantity Qf, a vehicle stop time from the time of turning off the system in the previous trip to the time of turning on the system in the present trip, a traveling distance in the previous trip, and travel time of the previous trip. Examples of the data further include an EV traveling distance in the previous trip, EV traveling time in the previous trip, an HV traveling distance in the previous trip, and HV traveling time in the previous trip. Examples of the data also include energy consumed by EV traveling in the previous trip, the energy consumed by HV traveling in the previous trip, and the state of charge SOC. Here, "one trip" starts when the system of the hybrid vehicle <NUM> is turned on (started) and ends when the system is turned off (stopped).

The presence of charging of the battery <NUM> by the battery charger <NUM> may be determined by determining whether the power supply plug <NUM> is connected to the external power supply <NUM> based on a connection signal SWC from the connection switch <NUM> and by determining increase in the state of charge SOC of the battery <NUM>. The charging time of connecting the power supply plug <NUM> of the battery charger <NUM> to the external power supply <NUM> (battery charger connection time) can be obtained by measuring the time of connecting the power supply plug <NUM> to the external power supply <NUM>. The charge amount of the battery <NUM> charged by the battery charger <NUM> can be obtained by integrating the battery current Ib of the battery <NUM> while the power supply plug <NUM> is connected to the external power supply <NUM>. The fuel supply quantity can be calculated based on values of the fuel gauge 25a before and after supply of oil to the fuel tank <NUM>. The fuel quantity Qf may be detected with the fuel gauge 25a. The vehicle stop time from the time of turning off the system in the previous trip to the time of turning on the system in the present trip can be obtained by counting time from the time of turning off the system in the previous trip to the time of turning on the system in the present trip.

The traveling distance in the previous trip can be obtained by subtracting a traveling distance at the time of turning on the system in the previous trip from a traveling distance at the time of turning on the system in the present trip. The traveling time in the previous trip can be obtained by counting time from the time of turning on the system in the previous trip to the time of turning off the system in the previous trip. The EV traveling time in the previous trip can be obtained as a sum total of the EV traveling time in the previous trip. The EV traveling distance in the previous trip can be obtained as a sum total of the EV traveling distance in the previous trip. The HV traveling time in the previous trip can be obtained as a sum total of the HV traveling time in the previous trip. The HV traveling distance in the previous trip can be obtained as a sum total of the HV traveling distance in the previous trip. The energy consumed by the EV traveling in the previous trip can be obtained by time-integrating the result obtained by multiplying a vehicle weight M by a vehicle speed V during EV traveling (∫M·Vdt). The vehicle weight M may be measured with a vehicle weight sensor, or may be calculated based on a slope sensor and on torque and acceleration of the motor MG2, or may be predetermined. The energy consumed by the HV traveling in the previous trip can be obtained by time-integrating the result obtained by multiplying the vehicle weight M by the vehicle speed V during HV traveling (fM. The state of charge SOC may be calculated based on an integrated value of the battery current Ib from the current sensor 51b.

Once the data necessary to calculate the utilization index IDX is input, the utilization index IDX is calculated using the input data, and is stored in an unillustrated RAM or an unillustrated flash memory of the HVECU <NUM> (step S110). In the embodiment, the utilization index IDX is calculated based on one or more of the following parameters (<NUM>) to (<NUM>). As the respective parameters are larger, charging (external charging) of the battery <NUM> by the battery charger <NUM> is determined to be performed more sufficiently.

The number of times of charging can be obtained by counting up the number based on the presence of charging of the battery <NUM> by the battery charger <NUM> input in step S100. The number of trips can be obtained by counting up the number whenever the system is turned on. It can be considered that the ratio of the number of times of charging to the number of trips reflects a ratio of the EV traveling utilization level to the total traveling utilization level. As the ratio is larger, utilization of charging of the battery <NUM> by the battery charger <NUM> can be determined to be 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.

The total time of connecting the battery charger <NUM> to the external power supply <NUM> can be obtained by integrating the charging time input in step S <NUM> during which the power supply plug <NUM> of the battery charger <NUM> is connected to the external power supply <NUM>. The total time of stopping the vehicle with the system being turned off (stop total time) can be obtained by integrating the vehicle stop time input in step S <NUM>, the vehicle stop time extending from the time of turning off the system in the previous trip to the time of turning on the system in the present trip. It can be considered that the ratio of the total time of connecting the battery charger <NUM> to the external power supply <NUM> to the total time of stopping the vehicle with the system being turned off serves as one factor that reflects the ratio of the EV traveling utilization level to the total traveling utilization level. As the ratio is larger, utilization of charging of the battery <NUM> by the battery charger <NUM> can be determined to be 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.

The total EV traveling distance can be obtained by integrating the EV traveling distance in the previous trip input in step S100. The total HV traveling distance can be obtained by integrating the HV traveling distance in the previous trip input in step S100. The ratio of the total EV traveling distance to the total HV traveling distance can be considered as a ratio of the EV traveling utilization level to the HV traveling utilization level. As the ratio is larger, the ratio of the EV traveling becomes larger, so that utilization of charging of the battery <NUM> by the battery charger <NUM> can be determined to be 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.

The total EV traveling time can be obtained by integrating the EV traveling time in the previous trip input in step S <NUM>. The total HV traveling time can be obtained by integrating the HV traveling time in the previous trip input in step S <NUM>. The ratio of the total EV traveling time to the total HV traveling time can be considered as a ratio of the EV traveling utilization level to the HV traveling utilization level. As the ratio is larger, the ratio of the EV traveling becomes larger, so that utilization of charging of the battery <NUM> by the battery charger <NUM> can be determined to be 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.

The total traveling distance can be obtained by integrating the traveling distance in the previous trip input in step S <NUM>. It can be considered that the ratio of the total EV traveling distance to the total traveling distance reflects a ratio of the EV traveling utilization level to the total traveling utilization level. As the ratio is larger, the ratio of the EV traveling becomes larger, so that utilization of charging of the battery <NUM> by the battery charger <NUM> can be determined to be 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.

The total traveling time can be obtained by integrating the traveling time in the previous trip input in step S100. It can be considered that the ratio of the total EV traveling time to the total traveling time reflects the ratio of the EV traveling utilization level to the total traveling utilization level. As the ratio is larger, the ratio of the EV traveling becomes larger, so that utilization of charging of the battery <NUM> by the battery charger <NUM> can be determined to be 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.

The total charge amount of the battery <NUM> charged by the battery charger <NUM> can be obtained by integrating the charge amount of the battery <NUM> by the battery charger <NUM> input in step S100. The total fuel supply quantity to the fuel tank <NUM> can be obtained by integrating the fuel supply quantity input in step S100. The ratio of the total charge amount of battery <NUM> charged by battery charger <NUM> to the total fuel supply quantity to the fuel tank <NUM> can be considered to reflect the ratio of the EV traveling utilization level to the HV traveling utilization level. As the ratio is larger, charging of the battery <NUM> by the battery charger <NUM> is utilized more, so that utilization of charging of the battery <NUM> by the battery charger <NUM> can be determined to be 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.

The integrated value of energy used for charging the battery <NUM> with electric power from the external power supply <NUM> can be obtained by integrating the charge amount. The integrated value of energy consumed for traveling can be obtained as an integrated value of EV traveling energy, and an integrated value of HV traveling energy. It can be considered that the ratio of the integrated value of energy used for charging the battery <NUM> with electric power from external power supply <NUM> to the integrated value of energy consumed for traveling reflects the ratio of the EV traveling utilization level to the total traveling utilization level. As the ratio is larger, external charging is performed more, so that utilization of charging of the battery <NUM> by the battery charger <NUM> can be determined to be 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.

The integrated value of energy consumed for the EV traveling can be obtained by integrating the EV traveling energy. The integrated value of energy consumed for the HV traveling can be obtained by integrating the HV traveling energy. It can be determined that the ratio of the integrated value of energy consumed for EV traveling to the integrated value of energy consumed for HV traveling reflects the ratio of the EV traveling utilization level to the HV traveling utilization level. As the ratio is larger, EV traveling is performed more, so that utilization of charging of the battery <NUM> by the battery charger <NUM> can be determined to be 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.

The total emission of carbon dioxide can be calculated as a sum of the result obtained by multiplying the total fuel supply quantity by a fuel coefficient and the result obtained by multiplying the total charge amount by an external charging coefficient. It can be considered that the ratio of the total traveling distance to the total emission of carbon dioxide reflects the ratio of the EV traveling utilization level to the total traveling utilization level. Carbon-dioxide emission per traveling distance is larger during traveling by fuel consumption than traveling by external charging. Therefore, as the ratio is larger, traveling by external charging is performed more, so that utilization of charging of the battery <NUM> by the battery charger <NUM> can be determined to be 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 utilization index IDX is calculated and stored in this way, the utilization index IDX is compared with a threshold IDXref (step S120). When the utilization index IDX is equal to or more than the threshold IDXref, the utilization status of external charging is determined to be sufficient, and the present routine is ended. When the utilization index IDX is less than the threshold IDXref, it is determined that the utilization status of the external charging is not sufficient. Accordingly, some processing, such as notification processing and function restriction processing, is conducted (step S130) to encourage the external charging, the notification processing being configured to perform notification such as announcement of a message "use external power supply to charge the vehicle" for example, the function restriction processing being configured to restrict the torque necessary for traveling and the like. Then, the present routine is ended.

In the hybrid vehicle <NUM> of the embodiment described in the foregoing, the utilization index IDX is calculated based on one or more of the aforementioned parameters (<NUM>) to (<NUM>) obtained based on the data reflecting the vehicle utilization status, and the calculated utilization index IDX is stored. Since the utilization index IDX is calculated such that as each parameter is larger, utilization of external charging is performed more sufficiently. Accordingly, the utilization index IDX can be used as an index that offers more accurate determination regarding the utilization status of external charging. As a result, various processing to promote external charging can be executed more appropriately.

In the hybrid vehicle <NUM> of the embodiment, the utilization index IDX is calculated based on one or more of the aforementioned parameters (<NUM>) to (<NUM>) obtained based on the data reflecting the vehicle utilization status. However, one of the parameters (<NUM>) to (<NUM>) may directly be used as the utilization index IDX.

According to a first aspect of the present invention, in the case of using any one of the parameters including (<NUM>) the ratio of the total EV traveling distance to the total HV traveling distance, (<NUM>) the ratio of the total EV traveling time to the total HV traveling time, (<NUM>) the ratio of the total EV traveling distance to the total traveling distance, (<NUM>) the ratio of the total EV traveling time to the total traveling time, and (<NUM>) the ratio of the total charge amount of the battery <NUM> charged by the battery charger <NUM> to the total fuel supply quantity to the fuel tank <NUM> for calculation of the utilization index IDX, the following is taken into consideration. In a trip with a large traveling distance or a traveling time, such as a trip with a traveling distance more than twice the EV traveling distance travelable with a fully-charged battery <NUM>, and a trip with a traveling time taken for normally traveling the traveling distance more than twice the EV traveling distance, execution of the EV traveling decreases the state of charge SOC of the battery <NUM> even with the battery <NUM> being fully charged at the start of traveling. As a result, the EV traveling shifts to the HV traveling, so that the distance and time of the HV traveling increases. Therefore, the fuel consumption also increases, which also causes increase in the fuel supply quantity to the fuel tank <NUM>. Accordingly, if the utilization index IDX is calculated based on any one of the parameters (<NUM>) to (<NUM>), which are calculated in the same way as in the case of a trip with a small traveling distance or with a short traveling time even though the trip has a long traveling distance or a long traveling time, the calculated utilization index IDX ends up leading to the determination that the utilization status of external charging is low. In order to avoid such inconvenience, the influence of the traveling distance or the traveling time on the utilization index IDX in the trip with a large traveling distance or the trip with a long traveling time is decreased. In this case, in the calculation of the utilization index IDX in step S <NUM> of the utilization index calculation processing routine in <FIG>, calculation of the parameters (<NUM>) to (<NUM>) may be skipped to use previous calculation values, or other parameters may be used instead of the parameters (<NUM>) to (<NUM>).

A parameter calculation processing routine illustrated in <FIG> may be used for parameter calculation in the case of maintaining the previous values. In the routine, first, the data inputting processing of the data same as that in step S <NUM> of the utilization index calculation processing routine in <FIG> is performed (step S200). The input traveling distance is compared with a distance threshold <NUM>, and the traveling time is compared with a time threshold <NUM> (step S210). Here, as the distance threshold <NUM>, a traveling distance more than twice the EV traveling distance travelable with the fully-charged battery <NUM> may be used for example. As the time threshold <NUM>, the time normally taken for traveling the traveling distance more than twice the EV traveling distance travelable with the fully-charged battery <NUM> may be used for example. When the traveling distance is equal to or more than the distance threshold <NUM> or when the traveling time is equal to more than the time threshold <NUM>, previous values are maintained (step S250) without calculation of the respective parameters (<NUM>) to (<NUM>), and the present routine is ended. That is, calculation of the respective parameters (<NUM>) to (<NUM>) is skipped. Thus, when the traveling distance is equal to or more than the distance threshold <NUM> or when the traveling time is equal to more than the time threshold <NUM>, calculation of the respective parameters (<NUM>) to (<NUM>) is skipped. Accordingly, it becomes possible to avoid inconvenience caused by calculating the respective parameters (<NUM>) to (<NUM>) using the vehicle utilization status data of a trip with a large traveling distance or a trip with a long traveling time. As a consequence, even in the case of a trip with a large traveling distance or a trip with a long traveling time, a more appropriate utilization index IDX can be calculated.

Meanwhile, when the traveling distance is less than the distance threshold <NUM> and the traveling time is less than the time threshold <NUM>, then it is determined whether or not the state of charge SOC at the time of turning on the system in the previous trip is equal to or more than a SOC threshold (step S220). Here, the SOC threshold is to indicate that the battery <NUM> is charged to some extent before the previous trip. For example, the SOC threshold may be a value such as <NUM>% and <NUM>%. When the state of charge SOC at the time of turning on the system in the previous trip is less than the SOC threshold, the respective parameters (<NUM>) to (<NUM>) are calculated as described in step S <NUM> of the utilization index calculation processing routine in <FIG> (step S240), and the present routine is ended. Meanwhile, when the state of charge SOC at the time of turning on the system in the previous trip is equal to or more than the SOC threshold, the traveling distance is compared with a distance threshold <NUM> that is smaller than the distance threshold <NUM>, and the traveling time is compared with a time threshold <NUM> that is smaller than the time threshold <NUM> (step S230). When the traveling distance is equal to or more than the distance threshold <NUM> or when the traveling time is equal to or more than the time threshold <NUM>, previous values are maintained (step S250) without calculation of the respective parameters (<NUM>) to (<NUM>), and the present routine is ended. When the state of charge SOC at the time of turning on the system in the previous trip is equal to or more than the SOC threshold, it indicates that charging was conducted before the previous trip. Accordingly, the above steps are performed to avoid, to some extent, the situation where the utilization index IDX leads to the determination that the utilization status of charging of the battery <NUM> by the battery charger <NUM> is low.

When the traveling distance is less than the traveling threshold <NUM> and the traveling time is less than the time threshold <NUM>, the respective parameters (<NUM>) to (<NUM>) are calculated as described in step S <NUM> of the utilization index calculation processing routine in <FIG> (step S240), and the present routine is ended. In the parameter calculation processing routine of <FIG>, when the traveling distance in the previous trip is equal to or more than the distance threshold <NUM>, when the traveling time is equal to or more than traveling time threshold <NUM>, or when the state of charge SOC at the time of turning on the system in the previous trip is equal to or more than the SOC threshold and the traveling distance in the previous trip is equal to or more than the distance threshold <NUM> or the traveling time is equal to or more than the time threshold <NUM>, calculation of the respective parameters (<NUM>) to (<NUM>) is skipped. However, calculation of the respective parameters (<NUM>) to (<NUM>) may be performed by multiplying the HV traveling distance, the HV traveling time, the traveling distance, and the traveling time by a coefficient smaller than the value <NUM>, the coefficient becoming smaller as the traveling distance is larger, or the traveling time becoming longer.

According to a second aspect of the present invention, in the case of using any one of the parameters including (<NUM>) the ratio of the number of times of charging to the number of trips and <NUM>) the ratio of the total time of connecting the battery charger <NUM> to the external power supply <NUM> to the total time of stopping the vehicle with the system being turned off, the following is be taken into consideration. When the state of charge of the battery <NUM> at the time of turning off the system in the previous trip is large, charging of the battery <NUM> by the battery charger <NUM> is not performed, or if performed, the charging process is completed in a short time. Accordingly, if the utilization index IDX is calculated based on any one of the parameters (<NUM>) and (<NUM>), which are calculated in the same way as in the case where the state of charge SOC of the battery <NUM> at the time of turning off the system in the previous trip is large, even when the state of charge SOC of the battery <NUM> at the time of turning off the system in the previous trip is small, the calculated utilization index IDX ends up leading to the determination that the utilization status of external charging is low. In order to avoid such inconvenience, the influence of charging or battery charger connection time on the utilization index IDX when the state of charge SOC of the battery <NUM> at the time of turning off the system is large is decreased. Also in this case, in the calculation of the utilization index IDX in step S <NUM> of the utilization index calculation processing routine in <FIG>, calculation of the parameters (<NUM>) and (<NUM>) may be skipped to use previous calculation values, or other parameters may be used instead of the parameters of (<NUM>) and (<NUM>).

A parameter calculation processing routine illustrated in <FIG> may be used for parameter calculation in the case of maintaining the previous values. In the routine, first, the data inputting processing of the data same as that in step S100 of the utilization index calculation processing routine in <FIG> is performed (step S300). The state of charge SOC of the battery <NUM> at the time of turning off the system in the previous trip is compared with a threshold (step S310). Here, the state of charge SOC of the battery <NUM> at the time of turning off the system in the previous trip is calculated based on an integrated value of the battery current Ib from the battery ECU <NUM> at the time of turning off the system in the previous trip. The battery ECU <NUM> inputs and stores the calculated SOC in an unillustrated RAM through the through communication, so that the calculated SOC can be obtained by reading the calculated SOC from the RAM. As the threshold, values in the vicinity of full-charge of the battery <NUM>, such as <NUM>% and <NUM>%, can be used, for example.

When the state of charge SOC of the battery <NUM> is less than the threshold, the respective parameters (<NUM>) and (<NUM>) are calculated as described in step S110 of the utilization index calculation processing routine in <FIG> (step S320), and the present routine is ended. When the state of charge SOC is equal to or more than the threshold, previous values are maintained (step S330) without calculation of the respective parameters (<NUM>) and (<NUM>), and the present routine is ended. That is, calculation of the respective parameters (<NUM>) and (<NUM>) is skipped. Thus, when the state of charge SOC of the battery <NUM> at the time of turning off the system in the previous trip is equal to or more than the threshold, calculation of the respective parameters (<NUM>) and (<NUM>) is skipped. Accordingly, it becomes possible to avoid the inconvenience caused by turning off the system while the state of charge SOC of the battery <NUM> is large. As a result, even when the state of charge SOC of the battery <NUM> at the time of turning off the system in the previous trip is large, a more appropriate utilization index IDX can be calculated. In the parameter calculation processing routine of <FIG>, calculation of the respective parameters (<NUM>) and (<NUM>) is skipped when the state of charge SOC of the battery <NUM> at the time of turning off the system in the previous trip is equal to or more than the threshold. However, the respective parameters (<NUM>) and (<NUM>) may be calculated by multiplying a coefficient smaller than the value <NUM>, the coefficient becoming smaller as a count value of the number of trips or the vehicle stop time becoming larger.

According to a third aspect of the present invention, in the case of using the parameter that is (<NUM>) the ratio of the number of times of charging to the number of trips for the calculation of the utilization index IDX, the following is taken into consideration. A connection of the power supply plug <NUM> of the battery charger <NUM> with the external power supply <NUM> without causing change in the state of charge SOC of the battery <NUM> or a trip without causing change in the state of charge SOC of the battery <NUM> may cause the inconvenience of calculating the utilization index IDX that leads to determination that the utilization status of external charging is higher or lower than the actual utilization status. Here, the connection of the power supply plug <NUM> of the battery charger <NUM> with the external power supply <NUM> without causing change in the state of charge SOC of the battery <NUM> includes connection of the power supply plug <NUM> to the battery <NUM> while the external power supply <NUM> is in a full-charge state, and connection of the power supply plug <NUM> of the battery charger <NUM> to the external power supply <NUM> immediately followed by cancel of the connection. The trip without causing change in the state of charge SOC of the battery <NUM> includes a trip in which the system is turned on (the system is started) but is then turned off (the system is stopped) without involving traveling. In order to avoid such inconvenience, in the case of the connection of the power supply plug <NUM> of the battery charger <NUM> with the external power supply <NUM> without causing change in the state of charge SOC of the battery <NUM> or the trip without causing change in the state of charge SOC of the battery <NUM>, the utilization index IDX is calculated, without counting up the number of times of charging and the number of trips. Also in this case, in the calculation of the utilization index IDX in step S110 of the utilization index calculation processing routine in <FIG>, calculation of the parameter (<NUM>) may be skipped to use a previous calculation value, or another parameter may be used instead of the parameter (<NUM>).

A parameter calculation processing routine illustrated in <FIG> may be used for parameter calculation in the case of maintaining the previous value. In the routine, first, the data inputting processing of the data same as that in step S100 of the utilization index calculation processing routine in <FIG> is performed (step S400). It is determined whether or not the state of charge SOC of the battery <NUM> has been changed by charging performed from the time of turning off the system in the previous trip to the time of turning on the system in the present trip and whether or not the state of charge SOC of the battery <NUM> has been changed by the previous trip (step S410). Here, whether or not the state of charge SOC of the battery <NUM> has been changed by charging may be determined based on whether or not the charge amount is equal to or more than a threshold or whether or not charger connection time is equal to or more than a threshold. Whether or not the state of charge SOC of the battery <NUM> has been changed by the previous trip may be determined based on the state of charge SOC at the time of turning on the system in the previous trip and the state of charge SOC at the time of turning off the system.

When the state of charge SOC of the battery <NUM> has been changed by charging, or when the state of charge SOC of the battery <NUM> has been changed by the previous trip, the parameter (<NUM>) is calculated as described in step S110 of the utilization index calculation processing routine in <FIG> (step S420), and the present routine is ended. Meanwhile, when the state of charge SOC of the battery <NUM> has not been changed by charging, or when the state of charge SOC of the battery <NUM> has not been changed by the previous trip, a previous value is maintained (step S430) without calculation of the parameter (<NUM>), and the present routine is ended. That is, calculation of the parameter (<NUM>) is skipped. By skipping the calculation of the parameter (<NUM>) in this way when the state of charge SOC of the battery <NUM> has not been changed by charging, or when the state of charge SOC of the battery <NUM> has not been changed by the previous trip, it becomes possible to avoid the inconvenience of calculating the utilization index IDX that leads to determination that the utilization status of charging is higher or lower than the actual utilization status. Accordingly, even when the case where the state of charge SOC of the battery <NUM> has not been changed by charging, or the case where the state of charge SOC of the battery <NUM> has not been changed by the previous trip occur, more appropriate utilization index IDX can be calculated.

According to the third aspect of the present invention, in the case of using the parameter that is (<NUM>) the ratio of the number of times of charging to the number of trips for the calculation of the utilization index IDX, the following is taken into consideration. When the traveling distance and traveling time in the previous trip are small, the inconvenience of calculating the utilization index IDX that leads to determination that the utilization status of external charging is higher or lower than the actual utilization status may occur. In order to avoid such inconvenience, when the traveling distance and traveling time of the previous trip are small, the utilization index IDX is counted, without counting up the number of times of charging and the number of trips. Also in this case, in the calculation of the utilization index IDX in step S110 of the utilization index calculation processing routine in <FIG>, calculation of the parameter (<NUM>) may be skipped to use a previous calculation value, or another parameter may be used instead of the parameter (<NUM>).

A parameter calculation processing routine illustrated in <FIG> may be used for parameter calculation in the case of maintaining the previous value. In the routine, first, the data inputting processing of the data same as that in step S100 of the utilization index calculation processing routine in <FIG> is performed (step S500). The traveling distance in the previous trip is compared with a distance threshold <NUM>, and the traveling time is compared with a time threshold <NUM> (step S510). Here, the distance threshold <NUM> may be a small distance, such as <NUM> and <NUM>. The time threshold <NUM> may be a short time such as <NUM> minutes and <NUM> minutes. When the traveling distance in the previous trip is equal to or more than the traveling threshold <NUM> and the traveling time is equal to or more than the time threshold <NUM>, the parameter (<NUM>) is calculated as described in step S110 of the utilization index calculation processing routine in <FIG> (step S520), and the present routine is ended. Meanwhile, when the traveling distance in the previous trip is less than the traveling threshold <NUM> or the traveling time is less than the time threshold <NUM>, the previous value is maintained (step S530) without calculation of the parameter (<NUM>), and the present routine is ended. That is, calculation of the parameter (<NUM>) is skipped. By skipping calculation of the parameter (<NUM>) in this way when the traveling distance and the traveling time in the previous trip is short, it becomes possible to avoid the inconvenience of calculating the utilization index IDX that leads to determination that the utilization status of charging is higher or lower than the actual utilization status. Accordingly, even when the case where the traveling distance and traveling time in the previous trip are short occurs, more appropriate utilization index IDX can be calculated.

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 driving 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>, so that motive power from the engine <NUM> is 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 is output to the driving shaft through the transmission <NUM>. The present invention may also be configured as a so-called 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 so as 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 utilization index 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 limited by the claims.

Claim 1:
An electronic control unit (<NUM>) configured to be included in a hybrid vehicle, and further configured to
i) calculate a utilization index of charging of a battery (<NUM>) by a battery charger (<NUM>) based on a ratio of an electric traveling utilization level to a hybrid traveling utilization level or a ratio of the electric traveling utilization level to a total traveling utilization level; and
ii) store the calculated utilization index
characterized in that
the electronic control unit (<NUM>) is configured to calculate the utilization index based on at least one of
a) a ratio of the number of times that the battery charger (<NUM>) charges the battery (<NUM>) to the number of trips, and
b) a ratio of total time of connecting the battery charger (<NUM>) to an external power supply to total vehicle stop time with a system of the vehicle being turned off,
c) a ratio of total electric traveling time achieved without involving operation of an engine to total hybrid traveling time achieved involving operation of the engine,
d) a ratio of the total electric traveling distance to a total traveling distance,
e) a ratio of the total electric traveling time to total traveling time,
f) a ratio of an integrated value of energy used to charge the battery by the battery charger to an integrated value of energy consumed for traveling,
g) a ratio of a total charge amount of the battery charged by the battery charger to a total fuel supply quantity to a fuel tank, and
h) a ratio of the total traveling distance to total emission of carbon dioxide,
wherein
the electronic control unit (<NUM>) is configured to calculate the utilization index such that influence of a vehicle utilization status on the utilization index is smaller in a trip with a large traveling distance than in a trip with a small traveling distance, based on at least one of
c) the ratio of the total electric traveling time to the total hybrid traveling time,
d) the ratio of the total electric traveling distance to the total traveling distance,
e) the ratio of the total electric traveling time to the total traveling time, and
g) the ratio of the total charge amount of the battery charged by the battery charger to the total fuel supply quantity to the fuel tank.