JP2011218854A - Start control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of insufficient drive force, even if charging amount of a battery is comparatively small in a hybrid vehicle.SOLUTION: A start control device (100) is carried on the hybrid vehicle (1) which includes rotary electric machines (MG1, MG2), energy storage device (12) which can supply power to the rotary electric machines, and power supply (11) which has output smaller than maximum output of a capacitor device. The start control device includes a controller (20) which starts the power supply on condition that the sum total of output of the capacitor device and output of the power supply becomes lower than the maximum output of the hybrid vehicle when the hybrid vehicle is running in an EV mode wherein the vehicle runs only with the power supplied from the capacitor device.

Description

  The present invention relates to a technical field of a start control device mounted on a vehicle including an engine and a motor such as a hybrid vehicle.

  As this type of device, for example, the engine is not started until the amount of charge of the battery reaches a limit value at which an output necessary for engine cranking is obtained, and when the limit value is reached, the remaining output is used to An apparatus for performing cranking has been proposed (see Patent Document 1). Alternatively, an apparatus that starts an engine and generates electric power when the driver request value is larger than the battery output limit value has been proposed (see Patent Document 2).

JP 2008-279970 A JP 2009-154715 A

  However, according to the background art described above, a case where an engine having an output smaller than the output by the battery (so-called low output engine) is mounted on the vehicle is not taken into consideration. Then, even if the engine is started when the amount of charge of the battery is small, there is a technical problem that the output requested by the user may not be provided.

  The present invention has been made in view of the above-described problems, for example, and proposes a start control device that can suppress the occurrence of insufficient driving force even when the amount of charge of a battery is relatively small. And

  In order to solve the above problems, a start control device of the present invention includes a rotating electrical machine, a power storage device capable of supplying power to the rotating electrical machine, and a power source having an output smaller than the maximum output of the power storage device. When the hybrid vehicle is traveling in the EV mode in which only the electric power supplied from the power storage device is traveling, the sum of the output of the power storage device and the output of the power source is And control means for starting the power source on the condition that the output is lower than the maximum output of the hybrid vehicle.

  According to the start control device of the present invention, the hybrid vehicle includes a rotating electrical machine, a power storage device, and a power source. The rotating electrical machine is, for example, various motors / generators capable of powering and power generation (that is, power regeneration). The power storage device is, for example, a lithium ion battery.

  The power source is, for example, an internal combustion engine, an external combustion engine, a fuel cell, a second power storage device different from the power storage device, or the like. Here, in particular, the power source is a power source whose output is smaller than the maximum output of the power storage device.

  For example, the control means including a memory, a processor, and the like is configured so that when the hybrid vehicle is traveling in an EV (Electric Vehicle) mode in which only the electric power supplied from the power storage device is traveling, the output of the power storage device and the power source The power source is started on the condition that the sum of the output and the output is lower than the maximum output of the hybrid vehicle.

  The “maximum output of the power storage device” means the output of the power storage device when the power storage device is fully charged (and the temperature of the power storage device is within an appropriate temperature range). On the other hand, the “output of the power storage device” means an output that can be currently taken out according to the current charging state of the power storage device, the current temperature, and the like.

  According to the inventor's research, the following matters have been found. That is, when the output of the power storage device decreases due to the decrease in the SOC (state of charge) of the power storage device as the hybrid vehicle continues in the EV mode, the output of the power storage device and the output of the power source May be less than the output required by the driver of the hybrid vehicle. On the other hand, for example, when the power source is started immediately when the output of the power storage device decreases (that is, when the EV mode is shifted to the HV (Hybrid Vehicle) mode), for example, the amount of exhaust gas, the running cost, and the like increase. there is a possibility.

  However, in the present invention, when the hybrid vehicle is traveling in the EV mode by the control means, the total of the output of the power storage device and the output of the power source is lower than the maximum output of the hybrid vehicle. The power source is started. That is, in the present invention, the power source is started when the sum of the output of the power storage device and the output of the power source becomes lower than the maximum output of the hybrid vehicle, which is the maximum value of the output that can be requested by the driver. (Ie, transition from EV mode to HV mode).

  For this reason, for example, while suppressing an increase in the amount of exhaust gas, traveling cost, etc., the total of the output of the power storage device and the output of the power source is suppressed to be lower than the output required by the driver (ie, insufficient driving force). In addition, a decrease in drivability can be suppressed.

  In one aspect of the start control device of the present invention, the maximum output of the hybrid vehicle is selected by a driver of the hybrid vehicle.

  According to this aspect, the maximum output of the hybrid vehicle (that is, the upper limit value of the output of the hybrid vehicle that is the maximum output that can be requested by the driver) is selected by the driver of the hybrid vehicle. It is set as a value less than the theoretical maximum output. In other words, the maximum output of the hybrid vehicle that determines whether or not the hybrid vehicle shifts from the EV mode to the HV mode is changed by the driver to a side that makes it difficult to shift from the EV mode to the HV mode.

  For this reason, since the period during which the hybrid vehicle travels in the EV mode becomes relatively long, it is possible to reduce the amount of exhaust gas during travel of the hybrid vehicle while suppressing a shortage of driving force. In addition, the fuel efficiency of the hybrid vehicle can be improved.

  In another aspect of the start control device of the present invention, the output of the power source is an output in the vicinity of the optimum fuel efficiency operating point of the power source or an output in the vicinity of the maximum output of the power source.

  Here, “near” means not only the output of the optimum operating point of the power source or the maximum output of the power source under ideal conditions, but also the intake air when the power source is an internal combustion engine or the like. The value includes the value included in the fluctuation range of the output of the optimum fuel consumption or the maximum output resulting from the temperature, the oil / water temperature, the secular change, the driving efficiency, and the like.

  In another aspect of the start control device of the present invention, the control means further outputs an output requested by a driver of the hybrid vehicle when the hybrid vehicle is traveling in the EV mode. The power source is started on condition that the output is larger than the output.

  According to this aspect, when the hybrid vehicle is traveling in the EV mode, if the output requested by the driver is larger than the output of the power storage device, the control means outputs the output of the power storage device and the output of the power source. Regardless of whether the total is lower than the maximum output of the hybrid vehicle, the power source is started (ie, the EV mode is shifted to the HV mode). For this reason, the output requested by the driver can be appropriately provided, which is very advantageous in practice.

  In another aspect of the start control device of the present invention, the hybrid vehicle is a hybrid vehicle (so-called plug-in hybrid vehicle) that can charge the power storage device from an external energy source.

  The effect | action and other gain of this invention are clarified from the form for implementing demonstrated below.

It is a block diagram which shows the structure of the hybrid vehicle by which the starting control apparatus which concerns on 1st Embodiment is mounted. It is a characteristic view which shows an example of the relationship between SOC of a battery and the output which can be output. It is a flowchart which shows the engine starting control process which ECU which concerns on 1st Embodiment performs. It is a timing chart explaining the effect of the starting control device concerning a 1st embodiment. It is a characteristic view which shows an example of the relationship between SOC of a battery and the output of a hybrid vehicle. It is a flowchart which shows the engine starting control process which ECU which concerns on 2nd Embodiment performs. It is a timing chart explaining the effect of the starting control device concerning a 2nd embodiment. It is a block diagram which shows the structure of the hybrid vehicle by which the starting control apparatus which concerns on 3rd Embodiment is mounted.

  An embodiment of a start control device according to the present invention will be described with reference to the drawings.

<First Embodiment>
A first embodiment of a start control device according to the present invention will be described with reference to FIGS. 1 to 4.

  First, the configuration of a hybrid vehicle on which the start control device according to the present embodiment is mounted will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing a configuration of a hybrid vehicle on which the start control device according to the present embodiment is mounted. In FIG. 1, dotted lines indicate electrical connection, and alternate long and short dash lines indicate signals. In FIG. 1, for convenience of explanation, only members that are directly related to the present embodiment are shown, and other members are not shown.

  In FIG. 1, a hybrid vehicle 1 includes an engine (ENG) 11, motor generators MG1 and MG2, a battery (BAT) 12, a PCU (Power Control Unit) 13, and an ECU (Electronic Control Unit) 20. Yes.

  For example, the battery 12 such as a lithium ion battery can supply power to the motor / generators MG1 and MG2 via the PCU 13, and the regenerative power of the motor / generators MG1 and MG2 is supplied via the PCU 13. It can be charged.

  The motor generator MG1 has a rotor connected to the drive shaft of the engine 11. The motor / generator MG1 generates electric power when the rotor rotates as the drive shaft of the engine 11 rotates. On the other hand, the motor / generator MG1 can crank the engine 11 when electric power is supplied from the battery 12 via the PCU 13.

  The motor / generator MG2 has a rotor connected to a power transmission mechanism. The motor / generator MG2 is supplied with power from the battery 12 or the motor / generator MG1 via the PCU 13, or is supplied with power from the battery 12 and the motor / generator MG1, via the power transmission mechanism. Driving force is output to the driving wheel 14. On the other hand, the motor / generator MG2 also functions as a regenerative brake.

  The hybrid vehicle 1 is a series-type hybrid vehicle that uses the engine 11 only for power generation and uses the motor / generator MG2 as a drive source of the hybrid vehicle 1.

  Here, the engine 11 will be described with reference to FIG. FIG. 2 is a characteristic diagram showing an example of the relationship between the state of charge of the battery and the output that can be output. In general, it is assumed that the SOC is 100% in the fully charged state, while the SOC is 0% indicates that the state of charge is zero.

  As shown in FIG. 2, the output of the engine 11 (refer to “low output engine output” represented by a one-dot chain line in FIG. 2) is lower than the maximum output of the battery 12. Therefore, it is difficult to provide the output requested by the driver of the hybrid vehicle 1 (hereinafter referred to as “user” as appropriate) only with the output of the engine 11.

  Returning to FIG. 1 again, when the hybrid vehicle 1 is traveling in the EV mode where only the electric power supplied from the battery 12 is traveling, the start control device 100 adds the output of the battery 12 and the output of the engine 11. However, the ECU 20 is configured to control the engine 11 so that the engine 11 is started on the condition that the output is lower than the maximum output of the hybrid vehicle 1.

  The “engine 11”, “motor / generators MG1 and MG2”, “battery 12”, and “ECU 20” according to the present embodiment are the “power source”, “rotary electric machine”, “power storage device” and It is an example of “control means”. In the present embodiment, a part of the ECU 20 for various electronic controls of the hybrid vehicle 1 is used as a part of the start control device 100.

  Next, an engine start control process executed by the ECU 20 during traveling mainly of the hybrid vehicle 1 equipped with the start control device 100 configured as described above will be described with reference to a flowchart of FIG. The engine start control process is executed regularly or irregularly or continuously while the hybrid vehicle 1 is mainly traveling.

  In FIG. 3, when the hybrid vehicle 1 is traveling in the EV mode, the ECU 20 determines whether or not the output that the battery 12 can output is equal to or less than the output requested by the user (step S101). Here, the output that can be output by the battery 12 means a control limit value that is changed depending on the SOC and temperature in consideration of deterioration and life of the battery 12. Further, the output requested by the user means a requested value of output based on the user's operation (for example, accelerator pedal depression amount) at a certain temporary point.

  When it is determined that the output that can be output by the battery 12 is less than or equal to the output requested by the user (step S101: Yes), the ECU 20 shifts the travel mode of the hybrid vehicle 1 from the EV mode to the HV mode (that is, The engine 11 is controlled so that the engine 11 is started) (step S102).

  On the other hand, when it is determined that the output that the battery 12 can output is larger than the output requested by the user (step S101: No), the ECU 20 determines that the sum of the output that the battery 12 can output and the output of the engine 11 is: It is determined whether it is below the maximum output of the hybrid vehicle 1 (step S103). Here, the output of the engine 11 means a value having a predetermined fluctuation range depending on, for example, the intake air temperature, the oil water temperature, the secular change, the operation efficiency, and the like. Moreover, the output of the hybrid vehicle 1 means a value having a fluctuation range that is allowable in consideration of, for example, merchantability.

  When it is determined that the sum of the output that can be output by the battery 12 and the output of the engine 11 is equal to or less than the maximum output of the hybrid vehicle 1 (step S103: Yes), the ECU 20 executes the process of step S102. On the other hand, if it is determined that the sum of the output that can be output by the battery 12 and the output of the engine 11 is greater than the maximum output of the hybrid vehicle 1 (step S103: No), the process returns to stop and enters a standby state. . That is, until the next processing start time that is uniquely determined by a predetermined cycle is reached, the execution of the processing in step S101 is stopped and a standby state is entered.

  Next, the effect of this embodiment will be described with reference to the timing chart of FIG. In FIG. 4, the solid line represents the case where the engine control process according to the present embodiment is performed, and the broken line represents the case where the engine control process according to the present embodiment has not been performed (that is, a conventional example). ing.

  As shown in FIG. 4, when the SOC of the battery 12 is an SOC that can output the maximum output of the hybrid vehicle 1, the maximum output of the hybrid vehicle 1 can be output only by the battery 12 (FIG. 4). (See time t1).

  When the output that can be output from the battery 12 decreases due to the decrease in the SOC of the battery 12, the sum of the output of the battery 12 and the output of the engine 11 becomes smaller than the maximum output of the hybrid vehicle 1.

  In this case, when the hybrid vehicle 1 continues the EV mode (see the broken line after time t2 in FIG. 4) and the user requests an output larger than the output that the battery 12 can output (see time t3 in FIG. 4). Assuming that the engine 11 is started, the user has the following problems: (i) the output that the battery 12 can output is reduced, and (ii) the output of the engine 11 is lower than the maximum output of the battery 12. The requested output may not be supplied.

  However, in this embodiment, when the sum of the output of the battery 12 and the output of the engine 11 becomes equal to or less than the maximum output of the hybrid vehicle 1 (see time t2 in FIG. 4), the engine 11 is started by the ECU 20, The travel mode is shifted from the EV mode to the HV mode. For this reason, the state which can supply the maximum output of the hybrid vehicle 1 which is the maximum value of the output which a user requests | requires can be maintained. In addition, since the EV mode can be continued until the sum of the output of the battery 12 and the output of the engine 11 becomes equal to or less than the maximum output of the hybrid vehicle 1, for example, an increase in the amount of exhaust gas, travel cost, etc. Can be suppressed.

  In this embodiment, for example, the engine 11 is controlled so that the SOC of the battery 12 can be maintained. However, for example, when the output of the battery 12 changes depending on the temperature of the battery 12, the battery The engine 11 may be controlled according to the temperature of 12.

  The hybrid vehicle 1 may be a hybrid vehicle (so-called plug-in hybrid vehicle) that can charge the battery 12 from an energy source outside the vehicle. That is, the start control device 100 according to this embodiment can be applied to a plug-in hybrid vehicle.

<Modification>
Next, a modified example of the start control device 100 according to the present embodiment will be described.

  In this modification, in the process of step S103 of the engine start control process shown in FIG. 3, the ECU 20 determines that “the sum of the output that can be output by the battery 12 and the output of the engine 11 is less than or equal to the maximum output of the hybrid vehicle 1. Instead of determining whether or not there is, it is determined whether or not the sum of the output that the battery 12 can output and the “maximum” output of the engine 11 is equal to or less than the maximum output of the hybrid vehicle 1. .

  In other words, in this modification, the hybrid vehicle 1 is allowed to operate in the EV mode by increasing the ratio of the output of the engine 11 to the maximum output of the hybrid vehicle 1 (see the second graph from the bottom in FIG. 4) as much as possible. The period during which the car can run is extended.

  As a result, the amount of exhaust gas while the hybrid vehicle 1 is traveling can be further reduced, and the fuel efficiency can be improved.

Second Embodiment
A second embodiment of the start control device of the present invention will be described with reference to FIGS. In the second embodiment, the configuration is the same as that of the first embodiment except that the maximum output of the hybrid vehicle is selected by the user. Accordingly, the description of the second embodiment that is the same as that of the first embodiment is omitted, and common portions in the drawing are denoted by the same reference numerals, and only the points that are basically different are shown in FIGS. The description will be given with reference.

  In the present embodiment, the maximum output of the hybrid vehicle 1 that is the maximum value of the output that can be requested by the user is selected in advance by the user within the range of the original maximum output of the hybrid vehicle 1 (see FIG. 5). That is, in this embodiment, the upper limit value of the output of the hybrid vehicle 1 is limited by the user.

  FIG. 5 is a characteristic diagram showing an example of the relationship between the SOC of the battery and the output of the hybrid vehicle. In FIG. 5, “vehicle maximum output” means the original maximum output of the hybrid vehicle 1, and “required upper limit power” means the maximum output of the hybrid vehicle 1 selected by the user (that is, limited by the user). The upper limit value of the output of the hybrid vehicle 1 is meant.

  Next, engine start control processing executed by the ECU 20 during traveling mainly of the hybrid vehicle 1 equipped with the start control device 100 configured as described above will be described with reference to the flowchart of FIG. 6.

  In FIG. 6, first, the ECU 20 determines whether or not there is a request for changing the maximum output value that can be requested by the user (step S201). When it is determined that there is no change request (step S201: No), the ECU 20 executes a process of step S203 described later. On the other hand, when it is determined that there is a change request (step S201: Yes), the ECU 20 sets the maximum value of the output that can be requested by the user to the value selected by the user (that is, the upper limit value of the output of the hybrid vehicle 1). ) Is changed (step S202).

  Next, when the hybrid vehicle 1 is traveling in the EV mode, the ECU 20 determines whether or not the output that the battery 12 can output is equal to or less than the output requested by the user (“threshold 1” in FIG. 5). (Refer to step S203).

  When it is determined that the output that can be output by the battery 12 is equal to or less than the output requested by the user (step S203: Yes), the ECU 20 shifts the travel mode of the hybrid vehicle 1 from the EV mode to the HV mode (step). S204).

  On the other hand, when it is determined that the output that the battery 12 can output is larger than the output requested by the user (step S203: No), the ECU 20 determines that the sum of the output that the battery 12 can output and the output of the engine 11 is: It is determined whether or not it is equal to or less than the maximum output value that can be requested by the user (that is, the upper limit value of the output of the hybrid vehicle 1 restricted by the user) (step S205).

  When it is determined that the sum of the output that can be output by the battery 12 and the output of the engine 11 is equal to or less than the maximum value that can be requested by the user (step S205: Yes), the ECU 20 executes the process of step S204. To do. On the other hand, if it is determined that the sum of the output that can be output by the battery 12 and the output of the engine 11 is greater than the maximum value that can be requested by the user (step S205: No), the process returns to stop and wait It becomes a state. In other words, until the next process start time that is uniquely determined by a predetermined cycle is reached, the execution of the process of step S201 is stopped and a standby state is entered.

  Next, the effect of this embodiment will be described with reference to the timing chart of FIG. In FIG. 7, the solid line represents the case where the upper limit value of the output of the hybrid vehicle 1 is restricted by the user (that is, corresponding to the second embodiment), and the broken line represents the upper limit value of the output of the hybrid vehicle 1 Represents the case where it is not limited by (that corresponds to the first embodiment).

  As can be seen from FIG. 7, when the upper limit value of the output of the hybrid vehicle 1 is restricted by the user, the ECU 20 can lower the SOC of the battery 12 that controls the engine 11 so that the engine 11 is started.

  For this reason, the period during which the hybrid vehicle 1 travels in the EV mode can be extended by a difference between the time t2 and the time t1 compared to the first embodiment. Accordingly, it is possible to further reduce the amount of exhaust gas during the traveling of the hybrid vehicle 1 and improve the fuel efficiency.

<Modification>
Next, a modified example of the start control device 100 according to the present embodiment will be described.

  In the present modification, in the process of step S205 of the engine start control process shown in FIG. 6, the ECU 20 determines that “the sum of the output that can be output by the battery 12 and the output of the engine 11 is the maximum output that the user can request. Instead of determining whether or not the value is equal to or less than the value, whether or not the sum of the output that can be output by the battery 12 and the “maximum” output of the engine 11 is equal to or less than the maximum value that the user can request No "is determined.

  That is, in this modification, the hybrid vehicle 1 is configured to increase the ratio of the output of the engine 11 (see the second graph from the bottom in FIG. 7) to the maximum output that can be requested by the user as much as possible. The period in which the vehicle can travel in the EV mode is extended.

<Third Embodiment>
A third embodiment of the start control device of the present invention will be described with reference to FIG. The third embodiment is the same as the configuration of the first embodiment except that the configuration of the hybrid vehicle on which the start control device is mounted is partially different. Therefore, the description of the third embodiment that is the same as that of the first embodiment is omitted, and common portions in the drawing are denoted by the same reference numerals, and only the points that are basically different refer to FIG. explain.

  The configuration of the hybrid vehicle on which the start control device according to this embodiment is mounted will be described with reference to FIG. FIG. 8 is a block diagram showing the configuration of a hybrid vehicle equipped with the start control device according to the present embodiment having the same concept as in FIG. 1.

  In FIG. 8, the hybrid vehicle 2 includes an engine 11, motor generators MG1 and MG2, a battery 12, a PCU 13, a planetary gear mechanism 15, and an ECU 20.

  The planetary gear mechanism 15 includes, for example, a sun gear S, a pinion gear, a carrier CA that supports the pinion gear so that it can rotate and revolve, and a ring gear R. The sun gear S of the planetary gear mechanism 15 is connected to the rotor of the motor / generator MG1, the carrier CA is connected to the engine 11 and the oil pump (O / P), and the ring gear R is connected to the power transmission mechanism. The motor / generator MG2 is coupled to the rotor.

  In the hybrid vehicle 2, the power of the engine 11 is divided by the planetary gear mechanism 15 and used for power generation by the motor / generator MG <b> 1 and driving of the hybrid vehicle 2. That is, the hybrid vehicle 2 uses at least a part of the motive power of the engine 11 for power generation, and uses a series / parallel system in which the other part of the motive power of the engine 11 and the motor / generator MG2 are used as a drive source of the hybrid vehicle 2. It is a hybrid vehicle.

  The present invention is not limited to a series type hybrid vehicle or a series / parallel type hybrid vehicle. For example, a hybrid vehicle that can switch between a series type and a parallel type, or a series type and a series / parallel type The present invention can also be applied to hybrid vehicles that can be switched to each other.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. Is also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 1, 2 ... Hybrid vehicle, 11 ... Engine, 12 ... Battery, 13 ... PCU, 20 ... ECU, 100 ... Start-up control apparatus, MG1, MG2 ... Motor generator

Claims (5)

Mounted on a hybrid vehicle comprising a rotating electrical machine, a power storage device capable of supplying power to the rotating electrical machine, and a power source having an output smaller than the maximum output of the power storage device,
When the hybrid vehicle is traveling in the EV mode where only the electric power supplied from the power storage device is traveling, the sum of the output of the power storage device and the output of the power source is greater than the maximum output of the hybrid vehicle. And a control means for starting the power source on the condition that the power source is low.   The start control apparatus according to claim 1, wherein the maximum output of the hybrid vehicle is selected by a driver of the hybrid vehicle.   The start control device according to claim 1, wherein the output of the power source is an output in the vicinity of an optimum operating point of fuel efficiency of the power source or an output in the vicinity of a maximum output of the power source.   The control means is further configured on the condition that an output requested by a driver of the hybrid vehicle is larger than an output of the power storage device when the hybrid vehicle is traveling in the EV mode. The start control device according to any one of claims 1 to 3, wherein the start control device is started.   The start control device according to any one of claims 1 to 4, wherein the hybrid vehicle is a hybrid vehicle capable of charging the power storage device from an external energy source.

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