Control system for a vehicle

Abstract

Control system for a vehicle (1) comprising: an engine (2) as a prime mover connected to a pair of drive wheels (7) to supply torque to the drive wheels (7), an electrical storage device (3) connected to the motor (2) to supply electrical power to the motor (2), and whose available output power is reduced due to an increase in an internal resistance value (R(n)) as a result of continuous discharging of the electrical power, a generation system (4) connected to the motor (2) for supplying electrical power to the motor (2) without passing through the electrical storage device (3), and a control device (13) which controls an output power of the electrical storage device (3) and a generation quantity (Pg(n)) of the generation system (4), characterized in that the control device (13) is configured to calculate a command value (Pc(n)) of the output power of the electrical storage device (3) to be transmitted to the motor (2) at a future time, predict the internal resistance value (R(n)) of the electrical storage device (3) at a point for discharging the electrical power from the electrical storage device (3) in a size of the command value (Pc(n)), to calculate a predicted value (Pp(n)) of the available output power of the electrical storage device at a future time based on the predicted internal resistance value (R(n)), to determine whether it is possible to discharge the electrical power from the electrical storage device (3) in the size of the command value (Pc(n)) at a future time, and to execute load reduction control for reducing the output power of the electrical storage device (3) by increasing an amount of electric power supplied to the motor (2) from the generation system (4) such that it becomes greater than an amount of electric power supplied to the motor (2) from the generation system (4) in a case where the electrical storage device (3) is expected to be able to discharge the electric power in the amount of the command value (Pc(n)) before a point at which the electrical storage device (3) can no longer discharge the electric power in the amount of the command value (Pc(n)) when the electrical storage device (3) is expected to be unable to discharge the electric power in the amount of the command value (Pc(n)), wherein the control device (13) is further configured to calculate the command value (Pc(n)) based on a change in the output power of the electrical storage device (3) within a predetermined past period (L1), and to increase the command value (Pc(n)) according to reductions in an external temperature and an external pressure.

Description

BackgroundField of the invention

[0001] Embodiments of the present invention relate to the technology of a drive control system for a vehicle driven by supplying electricity to a drive motor from a generator and / or a battery. Description of the state of the art

[0002] JP 2011-79447 A describes a hybrid drive control system for a hybrid vehicle, including a generator that converts power generated by an engine into electric power, and a motor to which the electric power generated by the generator and power accumulated in a battery are supplied to generate driving force. To avoid limiting the battery output due to an increase in internal resistance, the control system taught in JP 2011-79447 A calculates a total current charged and discharged to / from the battery within a predetermined period of time, as well as a square of the current. According to the teachings of JP 2011-79447 A, the battery current is controlled such that the total current does not exceed a first threshold, and the total square of the current does not exceed a second threshold.

[0003] JP H10-295045 A discloses a hybrid electric vehicle with battery management. According to the teachings of JP H10-295045 A, a maximum electric power is calculated based on a battery temperature and a battery state of charge. When the battery cannot output a requested electric power, an engine output is converted into electric power by a generator, and the electric power converted by the generator is supplied to a motor.

[0004] JP 2013-177091 A describes a control device of a hybrid vehicle configured to consume electricity (power) accumulated in a battery up to a lower limit of a charging amount when the vehicle reaches a predetermined scheduled charging point. According to the teachings of JP 2013-177091 A, when a distance to the predetermined scheduled charging point is reduced to become shorter than a predetermined value, an intermediate target level of a battery state of charge is reduced with a reduction in the distance to the predetermined scheduled charging point, and a maximum generation amount of a generator is increased.

[0005] JP 2017 - 94 894 A describes a control method for a hybrid vehicle having a motor connected to an output shaft of an engine, a high-voltage battery, an inverter that converts direct current supplied from the battery into alternating current and supplies it to the motor, a low-voltage battery connected to the high-voltage battery, and a DC-DC converter arranged between the high-voltage battery and the low-voltage battery.According to the teachings of JP 2017 - 94 894 A, when a charging rate of the high-voltage battery becomes equal to or lower than a predetermined lower limit, a control device performs control in which a power consumption of a DC-DC converter is acquired and a motor generator is caused to start a power generation operation by an engine, thereby generating power equal to or greater than the power consumption to charge the high-voltage battery.

[0006] As described, according to the teachings of JP 2011-79447A, the battery current is reduced when the total sum of the current charged and discharged to / from the battery and the square of the current exceed the threshold values. In this case, in order to generate the power required to drive the hybrid vehicle, it is necessary to cover the power deficit by generating electric power through the generator and supply the electric power generated by the generator to the motor, as taught by JP H10-295045A. Otherwise, it is necessary to cover the power deficit with the engine and supply the power generated by the engine to the drive wheels. However, if the maximum power of the engine is relatively small, for example,For example, when used in a range-extender vehicle, the power required to propel the vehicle may not be generated even if the engine produces maximum power. In this case, the motor must cover the power deficit by supplying electricity to the motor from the battery. As a result, the battery's output current cannot be limited as taught by JP 2011-79447 A, which may damage the battery. In addition, if the battery is thermally damaged, the power required to propel the vehicle may not be generated.

[0007] US 9 174 524 B2 discloses a control device for a vehicle comprising a drive motor, a power supply source comprising at least one generator and supplying power to the drive motor, and a control device.The control device is programmed to calculate a required drive torque based on the running condition of the vehicle, calculate a power supply value representing the power to be supplied from the power supply source to the drive motor based on the required drive torque, control the drive motor to enable the drive motor to output a drive torque determined by reducing a frequency component in the required drive torque that corresponds to a torsional vibration of the drive system, and control the power supply source to enable the power supply source to supply power to the drive motor obtained by reducing the frequency component in the power supply that corresponds to the torsional vibration of the drive system.

[0008] DE 29 45 436 T5 discloses a method and apparatus for recharging dry batteries, wherein the dry batteries are charged with one of several periods of an intermittently pulsating alternating current, and the batteries are allowed to discharge slightly during the periods between the charging pulses. The charging current is balanced according to the state of charge of the batteries, so that the batteries are charged with a constant average current regardless of the state of charge, possibly with variations depending on the sensitivity of the charging components to temperature and current intensity.The device comprises a transformer that steps down a mains current to a suitable charging voltage, a diode that allows periodic charging pulses to pass through, a resistor connected in parallel across the diode, and terminals for one or more dry batteries between the diode and the resistor on the one hand and a second terminal on the other. A Zener diode is connected in parallel across the dry batteries, and a resistor with a positive temperature coefficient is connected in series with it. The resistor is designed to compensate for the average charging current through the dry batteries in order to keep this current as constant as possible.

[0009] DE 10 2011 113 828 A1 discloses a method for determining the battery charge level of a battery in a battery-operated device with temporally varying power consumption. The method involves measuring the battery voltage and deriving a criterion for the battery charge level from this. The battery voltage is measured under at least two different load conditions or a selected characteristic load condition.

[0010] JP H10-271695 A1 discloses a battery remaining capacity detection device, wherein an internal resistance and an open-circuit voltage of the corresponding cell are determined according to a battery current and a lowest cell voltage of a battery. Depending on the internal resistance and the open-circuit voltage, a battery voltage required when the motor is delivering maximum power is determined. Then, a remaining time (equivalent to a remaining capacity of the battery) until the battery voltage drops to a voltage limit is estimated when the motor continues to deliver maximum power according to the battery voltage, and an internal combustion engine is driven to start power generation according to the remaining time. Summary

[0011] Modifications of embodiments of the present invention have been conceived in consideration of the above-described technical problems, and it is therefore an object of the present invention to provide a control system for a vehicle configured to prevent a reduction in driving force due to an increase in an internal resistance of an electric storage device.

[0012] This object is achieved by a control system for a vehicle as defined in claim 1.

[0013] Advantageous embodiments are specified in the dependent patent claims.

[0014] Thus, according to the exemplary embodiment of the present invention, the control device predicts the required power to be discharged from the electric storage device, and determines whether it is possible to discharge the predicted required power from the electric storage device in the future based on the internal resistance of the electric storage device, which increases depending on an operating condition.When it is expected that the electric storage device will not be able to discharge the required electric power, the control device performs the load reduction control to reduce a load of the electric power storage device by increasing, before a point at which the electric storage device can no longer discharge the required electric power, an amount of electric power supplied to the motor from the generation system so as to become larger than the amount of electric power supplied to the motor from the generation system in the case where it is expected that the electric storage device can discharge the electric power by the amount of the command value.Therefore, according to the exemplary embodiment of the present invention, the electric power supplied to the motor is not reduced due to an increase in the internal resistance of the electric storage device. Therefore, the driving force for propelling the vehicle is not limited due to a limitation in the output power of the electric storage device. Short description of the drawings

[0015] Features, embodiments and advantages of exemplary embodiments of the present invention will become more apparent from the following description and the accompanying drawings, which are not intended to limit the invention in any way. Fig. 1 is a schematic diagram illustrating a structure of a vehicle to which a control system according to an exemplary embodiment of the present invention is applied, Fig. 2 is a flowchart illustrating an example of a routine executed by the control system according to the exemplary embodiment of the present invention, Fig. 3 shows a map for predicting a future change in an output power of an electrical storage device, Fig. 4 is a block diagram illustrating procedures for calculating a predicted value of the output power of the electrical storage device, Fig. 5 shows a flowchart illustrating an example of a subroutine for executing load reduction control, Fig. 6 is a timing chart illustrating an example of a command value and the predicted value of an output power of the electric storage device, Fig. 7 is a timing chart illustrating an example of correcting the command value by increasing a power quantity of the generator, Fig. Fig. 8 is a timing chart illustrating an example of the predicted value of the output power of the electric storage device corrected based on the corrected command value, Fig. Fig. 9 is a timing chart illustrating the command value for a case where the generation size of the generator has been increased to the maximum value, Fig. 10 is a timing chart illustrating an example of advancing a timing for starting power generation of the generator, Fig. Fig. 11 is a flowchart illustrating another example of the subroutine for executing the load reduction control, Fig. 12 is a timing chart illustrating an example of a deficit in the output power of the electric storage device, Fig. 13 is a timing chart illustrating an example of the generation amount of the generator being increased based on the deficit of the output power of the electric storage device, Fig. Fig. 14 is a timing chart illustrating another example of correction of the command value by increasing the generation size of the generator, Fig. 15 is a timing chart illustrating another example of the predicted value of the output power of the electric storage device corrected based on the corrected command value, and Fig. 16 is a timing chart illustrating another example of advancing the timing for starting power generation of the generator. Detailed description of the preferred embodiments

[0016] An exemplary embodiment of the present invention is described below with reference to the accompanying drawings. With reference to Fig. 1 shows an example of a structure of a range-extending electric vehicle (hereinafter referred to simply as the “vehicle”) 1 to which the drive control system according to the exemplary embodiment of the present invention is applied. As shown in Fig. 1, the vehicle 1 comprises an engine (which is Fig. 1 is designated as “M”) 2, which serves as a prime mover, an electrical storage device (which is Fig. 1 is designated as “BATT”) 3, which supplies electric power to the motor 2, and an electric power generation system 4, also referred to as a generation system, which generates electric power for charging the electric storage device 3 and for covering a deficit of the electric power supplied from the electric storage device 3 to the motor 2.

[0017] For example, as in conventional hybrid vehicles and electric vehicles, a permanent magnet synchronous motor may be used as the motor 2, and a pair of drive wheels 7 are connected to an output shaft 5 of the motor 2 through a differential gear unit 6. Optionally, an additional gear train such as a gearbox may be arranged between the motor 2 and the drive wheels 7 to change a speed ratio between the motor 2 and the drive wheels 7. Thus, in the Fig. 1, a torque generated by the engine 2 is distributed to the drive wheels 7. Nevertheless, the control system according to the exemplary embodiment can also be applied to a vehicle in which each drive wheel is driven by an in-wheel motor, and to a vehicle in which the front wheels are driven by a front engine and the rear wheels are driven by a rear motor.

[0018] The motor 2 serves as a prime mover for generating torque to propel the vehicle 1 in both directions when electric power is supplied thereto. In addition, the motor 2 can also serve as a generator to partially convert kinetic energy of the vehicle 1 into electric power when torque is generated in one direction to reduce a speed of the drive wheel 7. The motor 2 is connected to the electric storage device 3 such that the motor 2 is operated as a motor by supplying electric power to the motor 2, and the electric storage device 3 is charged with the electric power generated by the motor 2.

[0019] For example, a lithium-ion battery, a capacitor, and an all-solid-state battery can be used as the electric storage device 3, wherein the electric storage device 3 outputs direct current electricity (hereinafter abbreviated as "DC electricity"). In contrast, the motor 2 is an alternating current motor (i.e., an "AC motor"). Therefore, an inverter 8 is arranged between the motor 2 and the electric storage device 3 so that the direct current electricity supplied from the electric storage device 3 is converted into alternating current electricity (hereinafter abbreviated as "AC electricity") of a predetermined frequency, and that the alternating current electricity generated by the motor 2 is converted into direct current electricity. Optionally, an additional converter may be arranged to raise a voltage of the electricity applied to the motor 2 (i.e., an input voltage).

[0020] To charge the electrical storage device 3 and to generate electric power to be supplied to the engine 2 in addition to the electric power supplied from the electrical storage device 3, the vehicle 1 is provided with the electric power generation system 4. According to the exemplary embodiment of the present disclosure, the electric power generation system 4 includes an engine (shown in Fig. 1 is designated as “ENG”) 9 and a generator (which is in Fig. 1 is designated as “G”) 10, which converts the kinetic power or kinetic energy generated by the engine 9 into electrical power.

[0021] For example, a gasoline engine and a diesel engine can be used as the engine 9, where the engine 9 generates power by combusting an air-fuel mixture. An output of the engine 9 can be controlled by controlling intake air, fuel injection, and ignition timing. As described above, the engine 9 is used to charge the electrical storage device 3 and generate electricity to be supplied to the engine 2. For these purposes, a small engine whose maximum output is smaller than a maximum output of the engine 2 is used as the engine 9.

[0022] Various types of conventional generators can be applied to the generator 10. According to the exemplary embodiment of the present disclosure, as with the engine 2, an AC motor such as a permanent magnet synchronous motor is applied as the generator 10. The generator 10 is connected to an output shaft 11 of the engine 9 such that the output of the engine 9 is partially converted into electric power by producing a reaction torque by the generator 10, and that a speed of the engine 9 is controlled in a manner with optimal fuel efficiency by controlling the reaction torque of the generator 10. In addition, the engine 9 is cranked (started) by operating the generator 10 as a motor.

[0023] As described, the AC motor is used as the generator 10. To convert the AC electricity generated by the generator 10 into DC electricity, an inverter 12 is arranged between the generator 10 and the electrical storage device 3. Optionally, a converter may be arranged between the generator 10 and the electrical storage device 3.

[0024] The inverter 8 and the inverter 12 are connected to each other in such a way that the electrical power can be exchanged directly between the inverters 8 and 12 without passing through the electrical storage device 3. This means that the electrical power generated by the generator 10 can be directly supplied to the engine 2 instead of the electrical storage device 3.

[0025] To control the motor 2, the inverter 8, the generator 10, the inverter 12, the engine 9, etc., the vehicle 1 is provided with an electronic control unit (hereinafter abbreviated as "ECU") 13 as a control device. The ECU 13 has a microcomputer as its main component, which is configured to perform calculation based on input data and equations and maps installed in advance, and to send the calculation results in the form of command signals to, for example, the motor 2, the generator 10, and the engine 9.

[0026] For example, the ECU 13 receives data from: an acceleration sensor that detects an operation amount of an accelerator pedal (gas pedal), a vehicle speed sensor that detects a speed of the vehicle 1, a resolver that detects a rotation angle and a speed of the motor 2, a pressure sensor that detects an external pressure, a temperature sensor that detects an outside temperature, a level sensor that detects a state of charge level (the state of charge is abbreviated as “SOC” (state of charge) hereinafter) of the electric storage device 3, a battery temperature sensor that detects a temperature of the electric storage device 3, a current sensor that detects a current value of the electricity supplied from the electric storage device 3, and a voltage sensor that detects a voltage of the electricity supplied to the motor 2.

[0027] To perform the calculation, for example, a map that determines a required power (or a driving force) for propelling the vehicle 1 based on a position of the accelerator pedal and a vehicle speed, a map that determines an internal resistance value of the electric storage device 3, and a map that determines deterioration of the electric storage device 3 are installed in the ECU 13.

[0028] The ECU 13 calculates the current value and current frequency supplied to the motor 2, the amounts of fuel and air supplied to the engine 9, and the current value and current frequency supplied to the generator 10 based on the input data and the maps. Calculation results are sent in the form of a command signal from the ECU 13 to the inverter 8 and the inverter 12, or to a throttle valve and a fuel injector (neither of which are shown).

[0029] As described, a required driving force (or power) for propelling the vehicle 1 is calculated based on a position of the accelerator pedal and a speed of the vehicle 1, and a required output torque of the motor 2 to achieve the required driving force is calculated. A target current value of the input current of the motor 2 is calculated based on the required output torque of the motor 2, and electric power is supplied from the electric storage device 3 to the motor 2 based on the target current value. In addition, the engine 9 is actuated (activated) as required to generate the electric power to be supplied to the motor 2 by the generator 10.For example, when the SOC level of the electric storage device 3 drops near a lower limit level, the electric power required to achieve the power required to propel the vehicle 1 cannot be supplied to the engine 2 only from the electric storage device 3. In this case, the engine 9 is actuated to drive the generator 10, thereby generating electric power corresponding to a deficit in the power for propelling the vehicle 1, and the electric power generated by the generator 10 is also supplied to the engine 2.

[0030] However, if the electric storage device 3 continuously charges or discharges electricity, an internal resistance value of the electric storage device 3 will temporarily increase, and as a result, an output current from the electric storage device 3 will be restricted. Specifically, when a large current is continuously discharged from the electric storage device 3 or when the electric storage device 3 is continuously charged with a large current, the internal resistance value of the electric storage device 3 will promptly increase. That is, the internal resistance value of the electric storage device 3 increases with an increase in the load of the electric storage device 3.

[0031] According to the exemplary embodiment of the present invention, the control system is configured to prevent a reduction in the driving force for propelling the vehicle 1 due to a temporary increase in the internal resistance value of the electrical storage device 3. For this purpose, in particular, the ECU 13 carries out a Fig. 2. In step S1, the ECU 13 calculates a command value Pc(n) of an output power of the electric storage device 3 to be transmitted at a future time. Specifically, based on a drive history up to the present time, including a history of the output power, the command value Pc(n) is continuously calculated at predetermined time intervals within a predetermined future time period from the present time.

[0032] An example of a method (or device) for calculating the command value Pc(n) is shown in Fig. 3. First, a change in the output power of the electrical storage device 3 within a predetermined elapsed time L1 before the current time is stored in the ECU 13, and a map is prepared for predicting a future change in the output power of the electrical storage device 3 based on a change in the output power of the electrical storage device 3 within the elapsed time L1. As indicated by a dashed line, according to the Fig. 3, the map is prepared such that the future change in the output power of the electric storage device 3 is predicted from the present time for a period of time three times longer than the past period L1.

[0033] Then, the map prepared in this way is corrected based on changes in the outside temperature and pressure. For example, when both the outside temperature and pressure gradually decrease, the ECU 13 assumes that the vehicle is traveling uphill and corrects the map so that the output of the electric storage device 3 gradually increases. In this case, if a reduction rate of the outside pressure gradually increases, the ECU 13 assumes that a road gradient gradually increases and gradually increases a correction amount of the map. In contrast, if the reduction rate of the outside pressure gradually decreases, the ECU 13 assumes that the road gradient gradually decreases and gradually reduces the correction amount of the map.

[0034] In addition, the ECU 13 predicts whether a condition for operating (activating) the generator 10 for preventing a reduction in the SOC level of the electric storage device 3 from the lower limit level will be satisfied after the elapse of a predetermined future time period T1. For example, the condition for operating the generator 10 is satisfied when the SOC level of the electric storage device 3 drops to the lower limit level. If the condition for operating the generator 10 is expected to be satisfied after the elapse of the future time period T1, the output power of the electric storage device 3 is corrected in consideration of a fact that the electric power generated by the generator 10 will be supplied to the motor 2 after the elapse of the future time period T1.Specifically, a generation amount of the generator 10 is subtracted from the output power of the electric storage device 3 after the elapse of the future time period T1. In this case, it is preferable to calculate the generation amount of the generator 10 based on an average speed of the vehicle 1 and a reduction (or reduction rate) of the SOC level of the electric storage device 3 during the past time period L1.

[0035] In addition, the output of the engine 9 varies depending on the intake air. That is, the output of the engine 9 decreases with a decrease in external pressure. Therefore, the generation amount of the generator 10 is corrected according to the external pressure.

[0036] In the upper part of Fig. 3, the solid line represents a change in the command value Pc(n) of the output power of the electric storage device 3 calculated in this way. In the lower part of Fig. 3, the dashed line drawn after the lapse of the future time period T1 indicates a change in the output of the engine 9 without correction according to the external pressure, and the solid line drawn after the lapse of the future time period T1 indicates the output of the engine 9 with correction according to the external pressure.

[0037] With further reference to Fig. 2, in step S2, the ECU 13 calculates a predicted value Pp(n) of the output power of the electrical storage device 3 at a future time. Specifically, the predicted value Pp(n) is also continuously calculated at predetermined time intervals within the predetermined future time period from the current time. An example of processing for calculating the predicted value Pp(n) is shown in Fig. 4. First, the command value Pc(n) at a time point for calculating the predicted value Pp(n), a temperature Tb(n-1) of the electric storage device 3 at a predetermined time before the time point for calculating the predicted value Pp(n), and a current outside temperature T0 are sent to a temperature predictor 14. Then, a temperature Tb(n) of the electric storage device 3 at the time point for calculating the predicted value Pp(n) is calculated based on the above-described data sent to the temperature predictor 14. Specifically, the temperature Tb(n) of the electric storage device 3 is calculated based on an amount of heat generation and an amount of heat discharge (heat dissipation) of the electric storage device 3, provided that the electric storage device 3 discharges the command value Pc(n).

[0038] To calculate the amount of heat generation of the electric storage device 3, a predetermined internal resistance of the electric storage device 3 in a case where the internal resistance value is not temporarily increased may be used. Otherwise, since the amount of heat generation of the electric storage device 3 increases with an increase in the internal resistance value of the electric storage device 3, a predicted value Rp(n-1) of the internal resistance calculated at a predetermined time before the time at which the predicted value Pp(n) is calculated may also be used to calculate the amount of heat generation of the electric storage device 3.

[0039] At the same time, the command value Pc(n) at the time of calculating the predicted value Pp(n) and an SOC level SOC(n-1) of the electric storage device 3 at a predetermined time before the time of calculating the predicted value Pp(n) are sent to an SOC predictor 15. Then, an SOC level SOC(n) of the electric storage device 3 at the time of calculating the predicted value Pp(n) is calculated based on the above-described data sent to the SOC predictor 15. For example, an SOC level SOC(n+1) of the electric storage device 3 after a predetermined time from the current time is calculated based on a command value Pc(n+1) after the predetermined time from the current time and a current SOC level SOC(n).Similarly, an SOC level SOC(n+2) of the electric storage device 3 after a predetermined time from a time point at which the SOC level SOC(n+1) has been calculated is calculated based on a command value Pc(n+2) after the predetermined time from the time point at which the SOC level SOC(n+1) has been calculated and the SOC level SOC(n+1).

[0040] Then, an internal resistance value R(n) of the electric storage device 3 at the time of calculating the predicted value Pp(n) is predicted by an internal resistance value predictor 16. For this purpose, the temperature Tb(n) of the electric storage device 3, the SOC level SOC(n) of the electric storage device 3, the command value Pc(n), and a degree of deterioration D of the electric storage device 3 at the time of calculating the predicted value Pp(n) are sent to the internal resistance value predictor 16. For example, the degree of deterioration D of the electric storage device 3 can be calculated based on an integrated value of the input power and the output power to / from the electric storage device 3.Note that the internal resistance value R(n) of the electrical storage device 3 may be predicted based on at least one of the input data described above. Alternatively, the internal resistance value R(n) of the electrical storage device 3 may also be predicted by referring to a map for determining the internal resistance value R(n) based on an integrated value of the current value during operation of the electrical storage device 3.

[0041] Next, the command value Pc(n), the SOC level SOC(n), and the internal resistance value R(n) are sent to a power prediction device 17, and the power prediction device 17 calculates the predicted value Pp(n) of the output power of the electric storage device 3 based on these input data. Specifically, the power prediction device 17 calculates an available output power of the electric storage device 3 by considering the SOC level SOC(n) and the internal resistance value R(n), and selects the smaller of the thus calculated available output power and the command value Pc(n) as the predicted value Pp(n).

[0042] With further reference to Fig. 2, in step S3, it is determined whether it is possible to discharge the electric power from the electric storage device 3 in the magnitude of the command value Pc(n) in the future. In other words, in step S3, it is determined whether the command value Pc(n) and the predicted value Pp(n) at a predetermined future time are equal to each other. If the output power of the electric storage device 3 is limited due to, for example, an increase in its internal resistance value, and thus the predicted value Pp(n) at the predetermined future time is smaller than the command value Pc(n), it may not be possible to discharge the electric power from the electric storage device 3 in the magnitude of the command value Pc(n) at the predetermined future time, and thus the answer of step S3 will be NO.In this case, the routine proceeds to step S4 to perform load reduction control to reduce a load on the electric storage device 3 (that is, to reduce the output power of the electric storage device 3). Specifically, in step S4, the load on the electric storage device 3 is reduced by increasing a generation amount of the electric power generation system 4 or advancing a timing for starting power generation of the electric power generation system 4 while obtaining the required driving force for propelling the vehicle 1. Thereafter, the routine returns. For example, when the SOC level of the electric storage device 3 is expected to drop to the lower limit level, an output power of the engine 9 is increased to increase the generation amount of the generator 10.Before a point at which the electric storage device 3 can no longer discharge the electric power in the magnitude of the command value Pc(n), the generation amount of the generator 10 is increased to be larger than a generation amount of the generator 10 in a case where the electric storage device 3 is expected to be able to discharge the electric power in the magnitude of the command value Pc(n) at the predetermined future time. Therefore, the amount of electric power supplied to the motor 2 from the electric storage device 3 is reduced. Otherwise, the engine 9 is started before the SOC level of the electric storage device 3 drops to the lower limit level, and the driving force is restricted due to an increase in the internal resistance value of the electric storage device 3.In this case, if the SOC level of the electric storage device 3 is not expected to drop to the lower limit level, the engine 9 may be started to a desired point to reduce the amount of electric power supplied to the motor 2 from the electric storage device 3 as necessary.

[0043] In contrast, if the command value Pc(n) and the predicted value Pp(n) are equal to each other at the predetermined future time, the electric power from the electric storage device 3 can be supplied to the motor 2 in the amount of the command value Pc(n). In this case, the answer of step S3 will be YES, and the routine proceeds to step S5 to control the output power of the electric storage device 3 based on the command value Pc(n) without executing the load reduction control. Thereafter, the routine returns.

[0044] Below, load reduction control processing is described in more detail with reference to Fig. 5. As described, the command value Pc(n) of the output power of the electric storage device 3 is calculated in step S1, and the predicted value Pp(n) of the output power of the electric storage device 3 is calculated in step S2.

[0045] With reference to Fig. 6 shows an example of the command value Pc(n) and the predicted value Pp(n) calculated based on the assumption that the vehicle 1 is driven by a constant power. In Fig. 6, the solid line represents the command value Pc(n), the dashed line represents the predicted value Pp(n), and the dash-dotted line represents the generation quantity Pg(n) of the electric power generation system 4. According to the Fig. In the example shown in Figure 6, at a point t0, the command value Pc is set to a value by which it is possible to obtain a required power for propelling the vehicle 1, and the electric power generation system 4 is not actuated (activated). Then, it is predicted that the condition for actuating the generator 10 is satisfied at a point t1. Consequently, a gradual increase in the generation amount Pg(n) of the electric power generation system 4 begins from the point t1, and at the same time, a gradual decrease in the command value Pc(n) begins from the point t1.

[0046] At point t2, the generation amount Pg(n) of the electric power generation system 4 is increased to a maximum value, but the power required to propel the vehicle 1 cannot be obtained solely by the electric power generated by the electric power generation system 4. Therefore, in this situation, the electric storage device 3 discharges a certain amount of electric power even after point t2 to cover a deficit of the electric power supplied to the motor 2. As described above, the internal resistance value of the electric storage device 3 is increased as a result of continuous discharge of the electric power from the electric storage device 3, and from point t3, the electric storage device 3 cannot further discharge the electric power in the amount of the command value Pc(n).Consequently, as indicated by the dashed line, the predicted value Pp(n) gradually decreases from the point t3 to below the command value Pc(n).

[0047] With further reference to Fig. 5, as already described, it is determined in step S3 whether the command value Pc(n) and the predicted value Pp(n) are equal to each other at the predetermined future time. According to the Fig. 6, the predicted value Pp(n) drops below the command value Pc(n) from the point t3, so the answer of step S3 will be NO. In this case, the routine proceeds to step S6 to determine whether it is possible to increase an amount of electric power Pg generated by the electric power generation system 4. For example, such a determination may be made in step S6 by determining whether there is (or will be) a time point at which the engine 9 does not generate (or will not generate) the maximum power currently or in the future. In this case, if there is (or will be) a time point at which the engine 9 does not generate (or will not generate) the maximum output power, the answer of step S6 is YES.Otherwise, such a determination can also be made in step S6 by determining whether the generator 10 is generating the maximum output power, which can be changed depending on a temperature of the generator 10. In this case, if the generator 10 is generating the current maximum power, the answer of step S6 is NO. According to the method shown in . Fig. In the example shown in Figure 6, the generation quantity Pg of the electric power generation system 4 is less than its maximum output power within a period from point t1 to point t2. Therefore, the answer of step S6 will be YES within the period from point t1 to point t2.

[0048] If the generation amount Pg of the electric power generation system 4 can be increased so that the answer of step S6 is YES, the routine proceeds to step S7 to calculate a command value Pc'(n) based on an assumption that the generation amount Pg of the electric power generation system 4 is increased by a predetermined amount ΔP. Specifically, in step S7, the command value Pc'(n) is calculated based on an assumption that the generation amount Pg(n) of the electric power generation system 4 is increased by the predetermined amount ΔP at the point at which the command value Pc(n) was calculated in step S1. That is, in step S7, the command value Pc(n) calculated in step S1 is corrected to the command value Pc'(n) by subtracting the increased amount ΔP of the generation amount Pg(n) of the electric power generation system 4 from the command value Pc(n).An example of the command value Pc'(n) calculated in step S7 is shown in . Fig. 7 shown. In Fig. 7, the solid line represents the command value Pc'(n) calculated in step S7, the dashed line broken by two dots represents the command value Pc(n) calculated in step S1, the dashed line represents a generation amount Pg'(n) of the electric power generation system 4 at the point at which the command value Pc'(n) was calculated in step S7, and the one-dot chain line represents the generation amount Pg(n) of the electric power generation system 4 at the point at which the command value Pc(n) was calculated in step S1.

[0049] Then, in step S8, a predicted value Pp'(n) is calculated based on an assumption that the electric storage device 3 discharges the electric power in an amount equal to the command value Pc'(n) calculated in step S7. Specifically, the predicted value Pp'(n) is calculated by replacing the command value Pc(n) calculated in step S1 with the command value Pc'(n) calculated in step S7 in the procedures for calculating the predicted value Pp(n) in step S2. In other words, the predicted value Pp'(n) is calculated by replacing the internal resistance value calculated in advance with an internal resistance value predicted based on an assumption that the electric storage device 3 discharges the electric power in an amount equal to the command value Pc'(n).That is, the internal resistance value R(n) of the electric storage device 3 is corrected based on the generation amount of the electric power generation system 4.

[0050] Next, in step S9, it is determined whether the predicted value Pp'(n) calculated in step S8 is substantially equal to the command value Pc'(n) calculated in step S7. That is, as in the previous step S3, in step S9, it is determined whether the electric power from the electric storage device 3 can be supplied to the motor 2 in the magnitude of the command value Pc'(n).

[0051] If the predicted value Pp'(n) is substantially equal to the command value Pc'(n) so that the answer of step S9 is YES, the routine proceeds to step S10 to set the target output power of the electric storage device 3 to the command value Pc'(n) and to set a target generation amount of the electric power generation system 4 to the generation amount Pg'(n). After that, the routine returns.

[0052] In contrast, if the predicted value Pp'(n) is smaller than the command value Pc'(n), as shown in Fig. 8, so that the answer of step S9 is NO, the routine returns to step S6. In this case, the command value Pc'(n) is repeatedly updated while increasing the generation amount Pg(n) of the electric power generation system 4 until the electric power can be supplied to the motor 2 in the amount of the command value Pc'(n), or until the generation amount Pg(n) cannot be increased further.

[0053] Otherwise, if the generation quantity Pg of the electric power generation system 4 cannot be further increased, the answer of step S6 will be NO. For example, as shown in Fig. 9, if the generation amount Pg(n) of the electric power generation system 4 has been increased to the maximum value as a result of repeating step S7, the answer of step S6 will be NO. In this case, the routine proceeds to step S11 to determine whether it is possible to advance a timing for starting power generation of the electric power generation system 4. If the electric power generation system 4 has already started power generation, so that the answer of step S11 is NO, the routine proceeds to step S12 to resume power generation of the electric power generation system 4.Specifically, in step S12, the generation amount of the electric power generation system 4 is set to the maximum value, and a target value of the output power of the electric storage device 3 is set to the command value Pc(n) calculated based on the generation amount of the electric power generation system 4. After that, the routine returns.

[0054] In contrast, when the timing for starting power generation of the electric power generation system 4 can be advanced so that the answer of step S11 is YES, the routine proceeds to step S13 to calculate a command value Pc'(n) based on an assumption that power generation of the electric power generation system 4 is started at a predetermined time Δt earlier than an end point of the future period T1 at which the condition for starting the engine 9 is satisfied. Specifically, in step S13, the command value Pc'(n) is calculated based on an assumption that power generation of the electric power generation system 4 is started by a predetermined time Δt earlier than the timing at which power generation of the electric power generation system 4 is started at the time of calculating the command value Pc(n) in step S1.For example, the timing for starting power generation of the electric power generation system 4 can be advanced by setting the lower limit level of the SOC level of the electric storage device 3 to a higher level.

[0055] Then, in step S14, a predicted value Pp'(n) is calculated based on an assumption that the electric storage device 3 discharges the electric power in an amount equal to the command value Pc'(n) calculated in step S13. Specifically, the predicted value Pp'(n) is calculated by replacing the command value Pc(n) calculated in step S1 with the command value Pc'(n) calculated in step S13 in the procedures for calculating the predicted value Pp(n) in step S2.

[0056] Next, in step S15, it is determined whether the predicted value Pp'(n) calculated in step S14 is equal to the command value Pc'(n) calculated in step S13. That is, as in the previous step S3, in step S15, it is determined whether the electric power from the electric storage device 3 can be supplied to the motor 2 in the magnitude of the command value Pc'(n).

[0057] If the predicted value Pp'(n) is equal to the command value Pc'(n), so that the answer of step S15 is YES, the routine proceeds to step S16. In step S16, a target output of the electric storage device 3 is set to the command value Pc'(n), the timing for starting power generation of the electric power generation system 4 is advanced to a time point at which the predicted value Pp'(n) and the command value Pc'(n) are equal to each other, and a target generation amount of the electric power generation system 4 after starting power generation is set to the maximum value. Thereafter, the routine returns.

[0058] In contrast, if the predicted value Pp'(n) is smaller than the command value Pc'(n), so that the answer of step S15 is NO, the routine returns to step S11. In this case, the timing for starting power generation of the electric power generation system 4 is repeatedly advanced by the predetermined time Δt until the predicted value Pp'(n) and the command value Pc'(n) are equal to each other, or until the timing for starting power generation of the electric power generation system 4 cannot be advanced any further. Fig. 10 shows an example of the command value Pc'(n) in the case where the predicted value Pp'(n) and the command value Pc'(n) are equal to each other as a result of advancing the timing for starting power generation of the electric power generation system 4. In Fig. 10, the solid line represents the command value Pc'(n) and the dashed line represents a power generation amount Pg'(n) of the electric power generation system 4 in this case.

[0059] When the command value Pc(n) and the predicted value Pp(n) are equal to each other so that the answer of step S3 is YES, the routine proceeds to step S5 to control the output power of the electric storage device 3 based on the command value Pc(n) without executing the load reduction control.

[0060] Thus, when it is expected that the electric storage device 3 will not be able to discharge the electric power equal to the command value Pc(n), for example, due to an increase in the internal resistance value, a generation amount of the electric power generation system 4 is increased, or a timing for starting power generation of the electric power generation system 4 is advanced to a point before the point at which the electric storage device 3 no longer discharges the electric power equal to the command value Pc(n). Therefore, according to the exemplary embodiment of the present invention, the load of the electric storage device 3 can be reduced in advance before the output power thereof is restricted due to an increase in the internal resistance value.For this reason, the driving force for propelling the vehicle 1 will not be reduced due to a lack of electrical power supplied to the motor 2.

[0061] Furthermore, the required output power of the electric storage device 3 is calculated according to the current time while determining whether the vehicle 1 is traveling uphill and predicting a road gradient. Therefore, according to the exemplary embodiment of the present invention, the command value Pc(n) can be accurately calculated in accordance with an actual required output power of the electric storage device 3.

[0062] Furthermore, a temperature and an SOC level of the electric storage device 3 in the future are predicted based on the predicted output power of the electric storage device 3 (ie, the command value), and an internal resistance value of the electric storage device 3 is predicted based on the predicted command value, the temperature, and the SOC level. Therefore, according to the exemplary embodiment of the present invention, the electric power that can be discharged from the electric storage device 3 in the future can be accurately predicted.

[0063] Furthermore, when the power generation amount of the electric power generation system 4 cannot be further increased, the timing for starting power generation of the electric power generation system 4 is advanced. Therefore, according to the exemplary embodiment of the present invention, the engine 9 can be prevented from being frequently actuated (activated), and an operating time of the engine 9 can be reduced.

[0064] With reference to Fig. Figure 11 shows another example of the subroutine for executing load reduction control. As described, the command value Pc(n) of the output power of the electric storage device 3 is calculated in step S1, and the predicted value Pp(n) of the output power of the electric storage device 3 is calculated in step S2.

[0065] With reference to Fig. Figure 12 shows another example of the command value Pc(n) and the predicted value Pp(n) calculated based on the assumption that the vehicle 1 is driven by a constant power. Fig. 12, the solid line represents the command value Pc(n), the dashed line represents the predicted value Pp(n), and the dash-dotted line represents the generation quantity Pg(n) of the electric power generation system 4. According to the Fig. In the example shown in Figure 12, at point t10, the command value Pc is set to a value that can generate the required power for propelling the vehicle 1, and the electric power generation system 4 is not actuated. Then, satisfaction of the condition for actuating (activating, putting into operation) the generator 10 is predicted at point t11. Consequently, the generation amount Pg(n) of the electric power generation system 4 starts gradually increasing from point t11, and at the same time, the command value Pc(n) starts gradually decreasing from point t11.

[0066] At point t12, the generation amount Pg(n) of the electric power generation system 4 is increased to the maximum value, but the power required to propel the vehicle 1 cannot be obtained solely by the electric power generated by the electric power generation system 4. Therefore, in this situation, the electric storage device 3 discharges a certain amount of electric power even after point t12 to cover a deficit of the electric power supplied to the motor 2. As described above, the internal resistance value of the electric storage device 3 is increased as a result of the continuous discharge of electric power from the electric storage device 3, and the electric storage device 3 cannot further discharge the electric power in the amount of the command value Pc(n) from point t13.Consequently, as indicated by the dashed line, the predicted value Pp(n) gradually decreases from point t13 to below the command value Pc(n).

[0067] With further reference to Fig. 11, as also described, it is determined in step S3 whether the command value Pc(n) and the predicted value Pp(n) are equal to each other at the predetermined future time. According to the Fig. 12, the predicted value Pp(n) drops below the command value Pc(n) from point t13, so the answer of step S3 will be NO. In this case, the routine proceeds to step S21 to calculate a deficit ΔPh of the electric power (i.e., energy) for propelling the vehicle 1 by calculating the area of the dashed region after point t13. Specifically, the deficit ΔPh can be calculated by integrating a difference between the command value Pc(n) and the predicted value Pp(n) from point t13, at which the predicted value Pp(n) starts to drop below the command value Pc(n), to an end point of a calculation period.

[0068] Then, in step S22, it is determined whether it is possible to cover the deficit ΔPh calculated in step S21 by increasing the generation amount of the electric power generation system 4. For example, if it is estimated that the generation amount of the electric power generation system 4 will be increased to the maximum value, it is determined in step S22 whether it is possible to cover the deficit ΔPh by reducing a time for increasing the generation amount of the electric power generation system 4 to the maximum value. An example of a procedure for increasing the generation amount of the electric power generation system 4 is shown in Fig. 13. According to the Fig. In the example shown in Figure 13, as indicated by the dashed two-dotted line, an increase rate of the power generation of the electric power generation system 4 is increased from a point after the lapse of a predetermined period of time from a point at which the power generation of the electric power generation system 4 was started. Consequently, the generation amount of the electric power generation system 4 is immediately increased to the maximum value. For this purpose, the increase rate of the power generation of the electric power generation system 4 and the timing for starting the increase rate increase can be adjusted in such a way that the dotted region in Fig. 13 is adjusted to the deficit ΔPh.

[0069] If the deficit ΔPh can be covered by increasing the generation amount of the electric power generation system 4, so that the answer of step S22 is YES, the routine proceeds to step S23 to calculate a command value Pc'(n) based on an assumption that the generation amount Pg of the electric power generation system 4 is increased. As with the previous step S7, in step S23, the command value Pc'(n) is calculated based on an assumption that the generation amount Pg(n) of the electric power generation system 4 is increased to the point at which the command value Pc(n) was calculated in step S1. That is, in step S23, the command value Pc'(n) is calculated by subtracting the increase amount ΔP of the generation amount Pg(n) of the electric power generation system 4 from the command value Pc(n) calculated in step S1. An example of the command value Pc'(n) calculated in step S23 is shown in Fig. 14 shown. In Fig. 14, the solid line represents the command value Pc'(n) calculated in step S23, the dashed line broken by two dots represents the command value Pc(n) calculated in step S1, the dashed line represents a generation amount Pg'(n) of the electric power generation system 4 at the point at which the command value Pc'(n) was calculated in step S23, and the one-dot chain line represents the generation amount Pg(n) of the electric power generation system 4 at the point at which the command value Pc(n) was calculated in step S1.

[0070] Then, in step S24, a predicted value Pp'(n) is calculated based on an assumption that the electric storage device 3 discharges the electric power in an amount equal to the command value Pc'(n) calculated in step S23. As in the previous step S23, the predicted value Pp'(n) can be calculated by replacing the command value Pc(n) calculated in step S1 with the command value Pc'(n) calculated in step S23 in the procedures for calculating the predicted value Pp(n) in step S2.

[0071] Next, in step S25, it is determined whether the predicted value Pp'(n) calculated in step S24 is equal to the command value Pc'(n) calculated in step S23. That is, as in the previous step S23, in step S25, it is determined whether the electric power from the electric storage device 3 can be supplied to the motor 2 by the command value Pc'(n). As described, the command value Pc'(n) is calculated based on the electric power deficit, which is calculated assuming that the electric storage device 3 discharges the electric power by the command value Pc(n) calculated in step S1. Therefore, the predicted value Pp'(n) substantially corresponds to the command value Pc'(n). However, the command value may be changed due to a deviation from actual values of an external temperature and a driving load from predicted values of these parameters.That is, such a determination is made in step S25 for the purpose of confirmation.

[0072] If the predicted value Pp'(n) is equal to the command value Pc'(n) so that the answer of step S25 is YES, the routine proceeds to step S26 to set the target output power of the electric storage device 3 to the command value Pc'(n) and to set the target generation amount of the electric power generation system 4 to the generation amount Pg'(n). After that, the routine returns.

[0073] Conversely, if the predicted value Pp'(n) is smaller than the command value Pc'(n) so that the answer of step S25 is NO, the routine proceeds to step S27 to recalculate the deficit ΔPh and then returns to step S22. In this case, steps S22 to S25 and step S27 are repeated until the predicted value Pp'(n) and the command value Pc'(n) equalize, or until the generation amount Pg(n) of the electric power generation system 4 cannot be further increased.

[0074] Otherwise, if the deficit ΔPh cannot be covered even if the generation amount Pg(n) of the electric power generation system 4 has been increased to the maximum value by repeating steps S22 to S25 and step S27 as shown in Fig. 15, the answer of step S22 will be NO. In this case, the routine proceeds to step S28 to determine whether it is possible to cover the deficit ΔPh calculated in step S21, S27, or step S34 described below by advancing the timing for starting power generation of the electric power generation system 4. If the electric power generation system 4 has already started power generation, or if the deficit ΔPh cannot be generated even if the electric power generation system 4 starts power generation immediately, the answer of step S28 will be NO.

[0075] If the answer of step S28 is NO, the routine proceeds to step S29 to continue the power generation of the electric power generation system 4 or to immediately start the power generation of the electric power generation system 4. Specifically, in step S29, an increase in the internal resistance value of the electric storage device 3 is suppressed as much as possible. To this end, the generation amount of the electric power generation system 4 is set to the maximum value, and the target value of the output power of the electric storage device 3 is maintained at the command value Pc'(n) calculated based on the generation amount of the electric power generation system 4. Thereafter, the routine returns.

[0076] In contrast, if the deficit ΔPh can be covered by advancing the timing for starting power generation of the electric power generation system 4, so that the answer of step S28 is YES, the routine proceeds to step S30 to calculate a command value Pc'(n) based on an assumption that the timing for starting power generation of the electric power generation system 4 is advanced to cover the deficit ΔPh. Specifically, in step S30, the command value Pc'(n) can be calculated by changing the timing for starting power generation of the electric power generation system 4 at the time of calculating the command value Pc(n) in step S1 to a timing at which it is possible to cover the deficit ΔPh.

[0077] Then, in step S31, a predicted value Pp'(n) is calculated based on an assumption that the electric storage device 3 discharges the electric power in an amount equal to the command value Pc'(n) calculated in step S30. Specifically, the predicted value Pp'(n) is calculated by replacing the command value Pc(n) calculated in step S1 with the command value Pc'(n) calculated in step S30 in the procedures for calculating the predicted value Pp(n) in step S2.

[0078] Next, in step S32, it is determined whether the predicted value Pp'(n) calculated in step S31 is equal to the command value Pc'(n) calculated in step S30. That is, as in the previous step S3, in step S31, it is determined whether the electric power from the electric storage device 3 can be supplied to the motor 2 by the command value Pc'(n). As described, the command value Pc'(n) is calculated based on the electric power deficit, which is calculated on the assumption that the electric storage device 3 discharges the electric power by the command value Pc(n) calculated in step S1. Therefore, the predicted value Pp'(n) substantially corresponds to the command value Pc'(n). However, the command value may be changed due to a deviation from actual values of an external temperature and a driving load from predicted values of these parameters.That is, such a determination is also made in step S32 for the purpose of confirmation.

[0079] If the predicted value Pp'(n) is equal to the command value Pc'(n), so that the answer of step S32 is YES, the routine proceeds to step S33. In step S33, the target output of the electric storage device 3 is set to the command value Pc'(n), the timing for starting power generation of the electric power generation system 4 is advanced to the time at which the predicted value Pp'(n) and the command value Pc'(n) are equal to each other, and the target generation amount of the electric power generation system 4 after starting power generation is set to the maximum value. Thereafter, the routine returns.

[0080] Conversely, if the predicted value Pp'(n) is smaller than the command value Pc'(n), so that the answer of step S32 is NO, the routine proceeds to step S34 to recalculate the deficit ΔPh and then returns to step S28. In this case, the timing for starting power generation of the electric power generation system 4 is advanced until the predicted value Pp'(n) and the command value Pc(n) are equal to each other, until it cannot be advanced any further, or until the deficit ΔPh becomes unmanageable (practical) even if the timing for starting power generation of the electric power generation system 4 is advanced. Fig. 16 shows another example of the command value Pc'(n) for the case where the predicted value Pp'(n) and the command value Pc(n) are equalized by advancing the timing for starting power generation of the electric power generation system 4. In Fig. 16, the solid line represents the command value Pc'(n) and the dashed line represents a generation amount Pg'(n) of the electric power generation system 4 in this case.

[0081] When the command value Pc(n) and the predicted value Pp(n) are equal to each other so that the answer of step S3 is YES, the routine proceeds to step S5 to control the output power of the electric storage device 3 based on the command value Pc(n) without executing the load reduction control.

[0082] As described above, the internal resistance value of the electric storage device is temporarily increased when the load of the electric storage device 3 is relatively high. Therefore, the advantages of the Fig. 2 by increasing the generation amount of the electric power generation system 4 based on the deficit ΔPh as an integrated value of the difference between the command value Pc(n) and the predicted value Pp(n).

[0083] Although the above-described exemplary embodiment of the present invention has been described, it will be understood by those skilled in the art that the present invention should not be limited to the described exemplary embodiments, and various changes and modifications can be made within the scope of the present invention. For example, execution of the load reduction control can be achieved by executing any of the Fig. 5 or Fig. 11 shown subroutines.

[0084] As described above, a control system for a vehicle for preventing a reduction in driving force due to an increase in the internal resistance value of an electric storage device (battery) is provided. A controller 13 calculates a command value Pc(n) of an output power of the battery 3 to be transmitted to a motor in the future, and predicts an internal resistance value R(n) of the electric storage device 3 at the point of discharging the electric power from the electric storage device 3 in the magnitude of the command value Pc(n).When it is expected that the electric storage device 3 will not be able to discharge the electric power in the magnitude of the command value Pc(n), the controller 13 reduces a load of the electric storage device 3 by increasing an amount of electric power supplied to the motor 2 from the generator 10 before the electric storage device 3 can no longer discharge the electric power in the magnitude of the command value Pc(n).

Claims

[1] Control system for a vehicle (1) comprising: an engine (2) as a prime mover connected to a pair of drive wheels (7) to supply torque to the drive wheels (7), an electrical storage device (3) connected to the motor (2) to supply electrical power to the motor (2), and whose available output power is reduced due to an increase in an internal resistance value (R(n)) as a result of continuous discharging of the electrical power, a generation system (4) connected to the motor (2) for supplying electrical power to the motor (2) without passing through the electrical storage device (3), and a control device (13) which controls an output power of the electrical storage device (3) and a generation quantity (Pg(n)) of the generation system (4), characterized by that the control device (13) is configured to calculate a command value (Pc(n)) of the output power of the electrical storage device (3) to be transmitted to the motor (2) at a future time, predict the internal resistance value (R(n)) of the electrical storage device (3) at a point for discharging the electrical power from the electrical storage device (3) in a size of the command value (Pc(n)), to calculate a predicted value (Pp(n)) of the available output power of the electrical storage device at a future time based on the predicted internal resistance value (R(n)), to determine whether it is possible to discharge the electrical power from the electrical storage device (3) in the size of the command value (Pc(n)) at a future time, and to execute load reduction control for reducing the output power of the electrical storage device (3) by increasing an amount of electric power supplied to the motor (2) from the generation system (4) such that it becomes greater than an amount of electric power supplied to the motor (2) from the generation system (4) in a case where the electrical storage device (3) is expected to be able to discharge the electric power in the amount of the command value (Pc(n)) before a point at which the electrical storage device (3) can no longer discharge the electric power in the amount of the command value (Pc(n)) when the electrical storage device (3) is expected to be unable to discharge the electric power in the amount of the command value (Pc(n)), wherein the control device (13) is further configured to calculate the command value (Pc(n)) based on a change in the output power of the electrical storage device (3) within a predetermined past period (L1), and to increase the command value (Pc(n)) according to reductions in an external temperature and an external pressure. [2] The control system for the vehicle (1) according to claim 1, wherein the load reduction control comprises a control to increase the generation amount (Pg(n)) of the generation system (4) before the point at which the electric storage device (3) can no longer discharge the electric power in the amount of the command value (Pc(n)) when the electric power is supplied to the motor (2) from the generation system (4). [3] Control system for the vehicle (1) according to claim 1, wherein the control device (13) is further configured to predict a time at which a predetermined condition for starting power generation of the generation system (4) will be met, and the load reduction control comprises a control for increasing the amount of electric power supplied to the motor (2) from the generation system (4) by advancing a timing for starting power generation of the generation system (4) to a point before a point at which the predetermined condition for starting power generation of the generation system (4) will be satisfied. [4] Control system for the vehicle (1) according to claim 1, wherein the control device (13) is further configured to predict a time at which a predetermined condition for starting the power generation of the generation system (4) will be met, and the load reduction controller comprises a controller for increasing the amount of electric power supplied to the motor (2) from the generation system (4) by advancing a timing for starting power generation of the generation system (4) to a point before a point at which the predetermined condition for starting power generation of the generation system (4) will be satisfied, while increasing the generation amount (Pg(n)) of the generation system (4) to a maximum value after starting power generation. [5] The control system for the vehicle (1) according to any one of claims 1 to 4, wherein the control means (13) is further configured to correct the command value (Pc(n)) and the internal resistance value (R(n)) based on the generation quantity (Pg(n)) of the generation system (4) during the execution of the load reduction control. [6] The control system for the vehicle (1) according to any one of claims 1 to 5, wherein the control means (13) is further configured to predict an internal resistance value (R(n)) based on a temperature, a state of charge level, and / or deterioration of the electric storage device (3) on the assumption that the electric storage device (3) discharges the electric power in the magnitude of the command value (Pc(n)). [7] Control system for the vehicle (1) according to one of claims 1 to 6, wherein the generating system (4) comprises a prime mover (9) and a generator (10), and a maximum output power of the prime mover (9) is smaller than a maximum output power of the motor (2).

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