JP2010174775A - Vehicle control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the excessive lowering of a capacity of a storage device caused by an engine stop demand, in a control device for a vehicle equipped with a rotary electric machine capable of generating electric power by an engine, and the storage device storing electric power generated by the rotary electric machine. <P>SOLUTION: This vehicle control device 40 for a hybrid vehicle includes a start instruction module 42 instructing the cranking start of the engine 14, a stop demand acquisition module 44 acquiring a stop demand of the engine 14, a SOC determination module 46 determining whether an SOC value of the storage device 22 is not greater than a predetermined threshold SOC, and a stop delay process module 48 continuing the operation of the engine 14 during a prescribed time necessary for the SOC value to exceed the threshold SOC when the SOC value is not greater than the threshold SOC and the stop demand of the engine 14 is acquired. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle control device, and more particularly, to a vehicle control device including a rotating electrical machine that can generate electric power with an engine and a power storage device that charges electric power generated by the rotating electrical machine.

  A vehicle including a rotating electrical machine that can generate electricity with an engine and a power storage device that charges electric power generated by the rotating electrical machine is called a hybrid vehicle. Since the performance of a power storage device mounted on a hybrid vehicle decreases or deteriorates when overdischarge or overcharge is performed, SOC (State Of Charge) is monitored as a state of charge indicator, and a predetermined charge limit threshold and discharge are monitored. Charging and discharging of the entire vehicle system is controlled so that the SOC is between the limit threshold value.

  For example, in Patent Document 1, as a method for operating a power generation internal combustion engine in a hybrid vehicle including an internal combustion engine for driving a power generator and a motor for driving a vehicle, the vehicle is stopped by operating a start key. In some cases, it is disclosed that when it is determined that the battery storage amount is lower than the predetermined battery storage amount, the engine is operated until the predetermined battery storage amount is reached, and the battery is reliably charged.

  Patent Document 2 discloses heat management control and exhaust gas regulation that are automatically activated during a soak time when an ignition switch (IGSW) is turned off in a vehicle electronic control system and the operating power of the electronic control system is not supplied. It is pointed out that the battery power is consumed for so-called perforated confirmation (evaporation check). Here, it is disclosed that after the IGSW is turned off, the engine is continuously driven to charge the battery until the charge amount of the battery becomes equal to or greater than a predetermined set value.

  In Patent Literature 3, as a charge control device for a hybrid vehicle, as a means for calculating the state of charge of the battery when the ignition switch is turned off, the engine performs intermittent idling with the rotational speed varying, and the resulting battery charge voltage is generated. It is disclosed that the internal resistance of the battery is obtained from the upper limit value and the lower limit value of the fluctuation of the charging current to know the charging state. Then, it is stated that the engine is rotated until the battery is in the start start state by the electric motor, and the battery is charged until the start start state is reached.

JP-A-5-328520 JP 2004-169670 A JP-A-11-33016

  As shown in the prior art, when the SOC is lower than a predetermined value, the generator is driven by the engine and charging is performed. To indicate this when the SOC is low, for example, a display prompting charging appears on the driver's seat or the like. By the way, if this display is ignored and the engine is stopped, the power storage device continues to discharge, so that the SOC continues to decrease. In this case, when the discharge of a certain value or more continues due to the decrease in the output of the power storage device, the READY-OFF control is automatically activated, and further discharge is suppressed.

  By the way, when the vehicle is started and cranking is started, the user may manually stop the engine. For example, cranking and manual stop may be repeated in a dealer inspection work or the like. In such a case, the READY-OFF control does not work because the discharge is short once. For this reason, it may occur that the capacity of the power storage device is too low.

  The objective of this invention is providing the vehicle control apparatus which can prevent that the capacity | capacitance of an electrical storage apparatus falls too much by the engine stop request | requirement.

  A vehicle control device according to the present invention is a vehicle control device including a rotating electrical machine that can generate electric power by an engine and a power storage device that charges electric power generated by the rotating electrical machine. A start instruction means for instructing start of cranking, a stop request acquisition means for acquiring an engine stop request, and an SOC determination for determining whether or not the SOC value indicating the state of charge of the power storage device is equal to or less than a predetermined threshold SOC When the engine stop request is acquired when the SOC value is equal to or less than the threshold SOC, the engine stop request is rejected or delayed for a predetermined time required for the SOC value to exceed the threshold SOC. And stop delay processing means for continuing the operation of the engine and thereafter receiving an engine stop request.

  With the above configuration, when the vehicle control apparatus acquires an engine stop request when the SOC value is equal to or lower than the threshold SOC, the vehicle control device requests the engine stop for a predetermined time required for the SOC value to exceed the threshold SOC. The engine operation is continued with refusal or delay, and then an engine stop request is accepted. Thus, even if there is an engine stop request, the engine operation is continued until the SOC exceeds the threshold SOC, so that it is possible to prevent the capacity of the power storage device from being excessively reduced due to the engine stop request.

It is a figure explaining the structure of the control system of the vehicle containing the vehicle control apparatus in embodiment which concerns on this invention. It is a flowchart explaining the procedure of the vehicle control of embodiment which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, a rotating electric machine connected to the power supply apparatus will be described as a representative example using one motor / generator having a motor function and a generator function, but this is a rotating electric machine having only a motor function. It is also possible to use one rotating electric machine having only one generator function. Further, as described in the embodiment, one motor generator may be used, or three or more motor generators may be used.

  The configuration of the power supply circuit connected to the rotating electrical machine will be described as having a power storage device, a voltage converter, a smoothing capacitor, and an inverter, but other elements other than these elements may be appropriately added. For example, a DC / DC converter, a low voltage power supply, a system main relay, or the like may be used. Further, a plurality of power storage devices may be used, and in this case, a plurality of voltage converters may be used. A plurality of inverters may be used.

  Below, the same code | symbol is attached | subjected to the same element in all the drawings, and the overlapping description is abbreviate | omitted. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is a diagram illustrating a configuration of a vehicle control system 10 including a vehicle control device 40. This vehicle control system 10 includes an engine 14, two rotating electrical machines 16 and 18, a power supply circuit 20 including a power storage device 22 and connected to the two rotating electrical machines 16 and 18, and these as control objects 12. The hybrid vehicle includes a vehicle control device 40 that controls the operation.

  The vehicle in this configuration is driven by the rotating electrical machine 18 and the engine 14 that are supplied with electric power from the power storage device 22, and the rotating electrical machine 16 is driven by the engine 14 to generate power to charge the power storage device 22. When the vehicle is braked, the regenerative energy is recovered by the rotating electrical machine 18 and the power storage device 22 is charged. However, depending on the specifications of the vehicle, the number of rotating electrical machines can be three or more. Further, as a configuration of the vehicle, only one rotating electric machine having a power generation function and an electric motor function may be connected to the engine.

  The engine 14 is an internal combustion engine, and has a function of driving the drive wheels of the vehicle and driving the rotating electrical machine 16 to generate electric power based on the output.

  The rotating electrical machine (MG1) 16 and the rotating electrical machine (MG2) 18 are motor generators (MG) mounted on the vehicle, and function as a motor when electric power is supplied from the power storage device 22, and are not illustrated. This is a three-phase synchronous rotating electric machine that functions as a generator when driven by an engine or braking a vehicle.

  The rotating electrical machine (MG1) 16 and the rotating electrical machine (MG2) 18 are motor generators (M / G) mounted on the vehicle, and function as a motor when electric power is supplied, and function as a generator during braking. It is a three-phase synchronous rotating electric machine. In the example of FIG. 1, one of the two rotating electrical machines 16 and 18 is used as a generator for charging the power storage device 22, and the other is used mainly as a drive motor for driving the vehicle. That is, as described above, one rotating electrical machine (MG1) 16 is driven by the engine 14 to be used as a generator, and the generated electric power is used to supply the power storage device 22. Also, the other rotating electrical machine (MG2) 18 is used for vehicle travel, receives power from the power storage device 22 during power running, functions as a motor to drive the vehicle axle, and functions as a generator during braking. Thus, the regenerative energy can be recovered and supplied to the power storage device 22.

  The power supply circuit 20 is a circuit connected to the rotating electrical machines 16 and 18 and supplies power to the rotating electrical machines 16 and 18 when they function as drive motors, or the rotating electrical machines 16 and 18 function as generators. Sometimes, it has a function of receiving the regenerative power and charging the power storage device 22. The power supply circuit 20 includes a power storage device 22 that is a secondary battery, a smoothing capacitor 24 on the power storage device 22 side, a voltage converter 26, a smoothing capacitor 28 on the inverters 30 and 32 side, and inverters 30 and 32. Is done.

  As the power storage device 22, for example, a lithium ion assembled battery or a nickel hydride assembled battery having a terminal voltage of about 200 V, a capacitor, or the like can be used.

  The voltage converter 26 is a circuit having a function of boosting the voltage on the power storage device 22 side to, for example, about 650 V using the energy storage action of the reactor, and is also called a boost converter. The voltage converter 26 has a bidirectional function, and when the power from the inverters 30 and 32 is supplied to the power storage device 22 as charging power, the high voltage on the inverters 30 and 32 is a voltage suitable for the power storage device 22. It also has an action to lower the blood pressure.

  The inverters 30 and 32 are configured to include a plurality of switching elements that operate under the control of the vehicle control device 40, and are circuits that perform power conversion between AC power and DC power. As shown in FIG. 1, the (MG1) inverter 30 is connected to the rotating electrical machine (MG1) 16, and the (MG2) inverter 32 is connected to the rotating electrical machine (MG2) 18.

  When the rotating electrical machine (MG1) 16 is caused to function as a generator, the inverter 30 converts the AC three-phase regenerative power from the rotating electrical machine (MG1) 16 into DC power and supplies it as a charging current to the power storage device 22 side. Has AC / DC conversion function. The inverter 32 connected to the rotating electrical machine (MG2) 18 converts DC power from the power storage device 22 side into AC three-phase driving power when the vehicle is in power running, and supplies the rotating electrical machine (MG2) 18 as driving power. An orthogonal conversion function to be supplied, and an AC / DC conversion function to convert alternating current three-phase regenerative power from the rotating electrical machine (MG2) 18 into direct current power and supply it as a charging current to the power storage device 22 when the vehicle is braking. Have.

  The smoothing capacitor 24 on the power storage device 22 side and the smoothing capacitor 28 on the inverters 30 and 32 side have a function of suppressing and smoothing fluctuations in voltage and current between the positive electrode bus and the negative electrode bus on the respective sides.

  The SOC detection unit 34 has a function of detecting an SOC value indicating the state of charge of the power storage device 22. Specifically, the input current to the power storage device 22 and the output current from the power storage device 22 are monitored, and the charge amount from time to time for the charge / discharge capability of the power storage device 22 is combined with the state of the terminal voltage of the power storage device 22. Is calculated and output to the vehicle control device 40.

  The start request unit 36 is an operator having a function of requesting start of the vehicle control system 10. Here, in particular, the operating element has a function of requesting start of cranking start of the engine 14. As the start request unit 36, for example, an ignition switch or the like can be used. The state of the start request unit 36 is transmitted to the vehicle control device 40 through an appropriate signal line.

  The READY-OFF unit 38 is an operator having a function of cutting a READY-ON signal that is a signal indicating that the vehicle can travel. The READY-ON signal is a signal that is automatically generated inside the vehicle control system 10 when a condition that the vehicle can run is satisfied. When this signal is output, for example, the engine 14 is started. be able to. Accordingly, when the READY-OFF unit 38 functions, this READY-ON signal is disconnected, so that, for example, the started engine 14 can be forcibly stopped. In that sense, the READY-OFF unit 38 is an operator that is operated when the user requests to stop the engine. As such a READY-OFF section, a READY-OFF switch provided separately from the ignition switch can be used. The state of the READY-OFF unit 38 is transmitted to the vehicle control device 40 through an appropriate signal line.

  The vehicle control device 40 has a function of controlling the operation of the rotating electrical machines 16 and 18 and the engine 14 mounted on the vehicle as a whole for the control object 12 through control of the power supply circuit 20 and the like. In particular, here, it has a function of performing control to prevent the capacity of the power storage device 22 from being excessively reduced due to an engine stop request. Such a vehicle control device 40 can be configured by a computer or the like suitable for mounting on a vehicle. The function of the vehicle control device 40 may be a part of the function of another on-vehicle computer. For example, the function of the vehicle control device 40 can be given to a hybrid ECU that controls the entire vehicle.

  The vehicle control device 40 acquires a vehicle start request and instructs the start of cranking of the engine 14, a stop request acquisition module 44 that acquires a stop request of the engine 14, and the SOC value of the power storage device 22. When the engine stop request is acquired when the SOC determination module 46 determines whether or not the threshold value SOC is lower than the predetermined threshold SOC and the SOC value is lower than the threshold SOC, the SOC value exceeds the threshold SOC. The engine is configured to include a stop delay processing module 48 that rejects or delays the engine stop request for a predetermined time required to continue the engine operation and then receives the engine stop request.

  Such a function can be realized by executing software, and specifically, can be realized by executing a vehicle control program. Some of these functions may be realized by hardware.

  The operation of the above configuration, particularly each function of the vehicle control device 40, will be described in detail with reference to the flowchart of FIG. FIG. 2 is a flowchart for explaining the procedure of vehicle control when a vehicle start request is issued and a stop request is made. Each procedure shows each processing procedure in the vehicle control program.

  When the vehicle is started, for example, an ignition key is turned on. In this case, the start request unit 36 shown in FIG. 1 serves as the ignition key. And the ON state of an ignition key is acquired, a power supply is supplied to the vehicle control apparatus 40, and a vehicle control program starts. Then, when the operation of the vehicle control device 40 starts, cranking of the engine 14 starts (S10). This step is executed by the function of the start instruction module 42 of the vehicle control device 40. Specifically, the vehicle control device 40 is initialized after the ignition key is turned on, and then cranking of the engine 14 is started according to a predetermined procedure of the vehicle control program.

  Alternatively, a start key or the like may be provided separately from the ignition key, and cranking of the engine 14 may be started by turning on the key. In addition, when one key having two operation positions is rotated, when it is turned to the first operation position, power is supplied to the vehicle control device 40, and when it is turned to the next operation position, cranking of the engine 14 is performed. May be performed. Since power can be supplied in a short time, in practice, the cranking of the engine 14 can be started by turning the key to the second operation position as it is with the first operation position as the elapsed position. .

  Next, it is determined whether a READY-OFF request has been acquired (S12). Here, the READY-OFF request is an engine stop request by the user, and means that the READY-OFF unit 38 in FIG. This process is executed by the function of the stop request acquisition module 44. Specifically, it is determined whether or not the READY-OFF switch that is the READY-OFF unit 38 is operated. A case where the READY-OFF switch is acquired is a READY-OFF request acquisition.

  If the READY-OFF request is not acquired, step S12 is repeated. That is, the engine 14 remains in the drive mode where the cranking is started and the engine 14 continues to operate. When the initial state of cranking has elapsed, the rotating electrical machine 16 can be driven as a generator by the engine 14, and the power storage device 22 can be charged by the start of power generation. Whether or not charging is actually performed can be determined according to the result of monitoring the SOC.

  If a READY-OFF request is acquired in S12, it is next determined whether or not the SOC value is equal to or less than a predetermined threshold SOC (S14). This process is executed by the function of the SOC determination module 46. The threshold SOC can be set with reference to a battery capacity reduction risk area where the state of charge of the power storage device 22 is overdischarged. For example, SOC = 30% can be set as the threshold SOC. Of course, this value is merely an example, and a different value may be set.

  When the determination of S14 is negative, that is, when it is determined that the SOC value exceeds the threshold SOC, the process of S14 is repeated. That is, the engine 14 remains in the drive mode where the cranking is started and the engine 14 continues to operate. Therefore, according to the result of monitoring the SOC, if necessary, the rotating electrical machine 16 generates power, the power storage device 22 is charged, and the SOC can be improved to an appropriate value range.

  If the determination in S14 is affirmative, that is, cranking is started and the engine stop request is continuously acquired, and the SOC value is equal to or less than the threshold SOC, the predetermined time required for the SOC value to exceed the threshold SOC It is determined whether or not elapses (S16). That is, only when the SOC is low, the READY-OFF request is delayed or temporarily rejected, and the operation of the engine 14 is continued until a predetermined time elapses after the engine start state is confirmed and the battery is confirmed to be charged. The

  For example, in the above example, if the threshold SOC is 30% and the SOC value at the time of determination in S14 is 20%, the engine stop request is acquired, but the request is not executed and the engine is not executed. 14 is kept in the cranking state and the operation of the engine 14 is continued. As a result, the rotating electrical machine 16 generates power with the driving force of the engine 14 and the power storage device 22 is charged. The predetermined time may be when the SOC value is monitored and the SOC value increases and exceeds the threshold SOC. Therefore, the predetermined time is a value that varies depending on the SOC value of power storage device 22.

  When the predetermined time has elapsed, a READY-OFF request acceptance process is performed (S18). Specifically, the operation of the engine 14 is stopped. The steps S16 and S18 are executed by the function of the stop delay processing module 48. When the predetermined time has elapsed, the state of charge of the power storage device 22 leaves the over-discharged battery capacity reduction risk area and exceeds the threshold SOC, so the READY-OFF request is executed for the first time individually. Thus, only when the SOC is low, the READY-OFF request is delayed or temporarily rejected, and when the battery assist is confirmed after exiting the engine start state, the READY-OFF request is permitted. Like repeated cranking and READY-OFF, it is possible to prevent the capacity of the power storage device from being excessively reduced due to an engine stop request.

  The vehicle control device according to the present invention can be used as a vehicle control device including a rotating electrical machine capable of generating electric power and a power storage device that charges electric power generated by the rotating electrical machine, like a hybrid vehicle. A plurality of rotating electrical machines may be used.

  DESCRIPTION OF SYMBOLS 10 Vehicle control system, 12 Control object, 14 Engine, 16, 18 Rotating electric machine, 20 Power supply circuit, 22 Power storage device, 24, 28 Smoothing capacitor, 26 Voltage converter, 30, 32 Inverter, 34 SOC detection part, 36 Start Request section, 38 READY-OFF section, 40 vehicle control device, 42 start instruction module, 44 stop request acquisition module, 46 SOC determination module, 48 stop delay processing module.

Claims (1)

A vehicle control device comprising: a rotating electrical machine that can generate electricity with an engine; and a power storage device that charges electric power generated by the rotating electrical machine,
Start instruction means for acquiring a vehicle start request and instructing start of cranking of the engine;
Stop request acquisition means for acquiring an engine stop request;
SOC determination means for determining whether or not the SOC value indicating the state of charge of the power storage device is equal to or less than a predetermined threshold SOC;
If the engine stop request is acquired when the SOC value is equal to or lower than the threshold SOC, the engine stop request is rejected or delayed for a predetermined time required for the SOC value to exceed the threshold SOC. And a stop delay processing means for subsequently accepting an engine stop request,
The vehicle control apparatus characterized by including.

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