JP6504071B2 - Hybrid vehicle - Google Patents

Description

  The present invention relates to a hybrid vehicle having an engine and a rotating electrical machine as power sources.

  BACKGROUND ART Conventionally, a hybrid vehicle having an engine and a rotating electrical machine as a power source is widely known. Such a hybrid vehicle is equipped with a main battery for supplying electric power to a rotating electrical machine and the like. The rotary electric machine functions as an electric motor that receives power supply and generates power, and also functions as a generator that receives power from an engine and regenerative torque to generate electric power. The electric power generated by the rotating electrical machine is sent to the main battery to charge the main battery.

  By the way, in such a hybrid vehicle, when the shift range is set to the neutral range (hereinafter referred to as "N range"), the driving force should not be transmitted to the wheels, so the rotating electric machine capable of driving the wheels Is turned off. When the power of the rotating electrical machine is turned off, of course, the main battery can not be charged by the rotating electrical machine. On the other hand, electric power is required to drive accessories and the like mounted on the vehicle. Therefore, while the N range is selected, the main battery is only discharged without being charged. As a result, when the N range is selected for a long time while the vehicle is stopped, the SOC of the main battery may decrease, and in some cases, the SOC may be depleted.

JP, 2008-094178, A

  Patent Document 1 discloses a hybrid vehicle that displays a warning for prompting the user to change the shift range if the SOC of the main battery falls below a prescribed value while the N range is selected while the vehicle is stopped. Is disclosed. According to this technology, if the SOC decreases while the vehicle is stopped, a change to a shift range (for example, a parking range or drive range) in which the main battery can be charged is prompted, so that SOC exhaustion can be effectively prevented. .

However, the technology of Patent Document 1 only promotes the change of the shift range when the SOC of the main battery decreases. In other words, in the technology of Patent Document 1, when the SOC of the main battery is high, the warning is not displayed even if the N range is stopped while being selected.
Therefore, the user can not recognize the problem when the N range is selected while the vehicle is stopped, and the N range may be frequently used while the vehicle is stopped. In this case, it is easy to transition to a low SOC state while the vehicle is stopped.

  Therefore, it is an object of the present invention to provide a hybrid vehicle in which it is difficult for the main battery to transition to a low SOC state while the vehicle is stopped.

The hybrid vehicle according to the present invention generates power by functioning as an internal combustion engine, a main battery that charges and discharges electric power, and a motor, and generates power to charge the main battery by functioning as a generator. The vehicle control system further includes: at least one rotating electric machine; and a control device that shuts down the rotating electric machine during a neutral stop in which neutral is selected as a shift range in a stopped state, and the control device If there was Tsu Do a predefined threshold value or more hours, the prompt changes the shift range to output a warning to the user, further, also the duration is less than the threshold time, integrated in the neutral stop when the amount of discharge current Tsu Do a predefined threshold amount of current more than the user a warning for prompting a change of the shift range Output, characterized in that.

  According to the present invention, regardless of the magnitude of the SOC, a warning is output when the amount of accumulated discharge current during the neutral stopping period or during the neutral period is large. As a result, it is difficult for the main battery to transition to a low SOC state.

FIG. 1 is a diagram showing a configuration of a hybrid vehicle according to an embodiment of the present invention. It is a flowchart which shows the flow of a presentation process of a warning.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of a hybrid vehicle 10 according to an embodiment of the present invention. Hybrid vehicle 10 includes an engine 12, a first rotating electrical machine MG1 and a second rotating electrical machine MG2 as drive sources. In the following description, when it is not necessary to distinguish between the first rotary electric machine MG1 and the second rotary electric machine MG2, the first rotary electric machine MG1 and the second rotary electric machine MG2 are simply referred to as "rotary electric machine MG".

  The engine 12 is an internal combustion engine that outputs power by hydrocarbon-based fuel such as gasoline or light oil. The operating state of the engine 12 is controlled by the engine ECU 38. In order to perform operation control of the engine 12, parameters detected by various sensors (not shown), for example, a pressure value in fuel quality, an air-fuel ratio, an intake air amount, and the like are input to the engine ECU 38.

  The rotary electric machine MG functions as a generator or functions as an electric motor according to the traveling state of the hybrid vehicle 10. When the rotary electric machine MG functions as a generator, regenerative braking is performed. The first rotary electric machine MG1 mainly functions as a generator, and generates electric power by the power from the engine 12. The first rotary electric machine MG1 also functions as a motor (starter motor) for starting the engine. The second rotating electrical machine MG2 mainly functions as an electric motor and outputs power for traveling the vehicle. In addition, the second rotating electrical machine MG2 also functions as a generator, and performs so-called regenerative power generation that decelerates the vehicle by converting kinetic energy of the vehicle into electrical energy. The inverter 22 performs current control between the main battery 28 and the rotary electric machine MG while converting power from direct current to alternating current or from alternating current to direct current. As will be described in detail later, when the neutral range (hereinafter referred to as “N range”) is selected as the shift range, the switching element of inverter 22 is turned off and rotary electric machine MG is stopped (non-drive state ).

  The power generated by engine 12 and rotary electric machine MG is transmitted to wheels 20 via drive shaft 18 and transmission 16. Further, the power generated by the engine 12 is distributed by the power split mechanism 14 into two paths of the wheel 20 and the first rotating electrical machine MG1. The power split mechanism 14 is a planetary gear mechanism provided with a planetary carrier, a sun gear and a ring gear in order to distribute the power of the engine 12 to both the wheel 20 and the first rotary electric machine MG1. The engine 12 is connected to a planetary carrier, the first rotary electric machine MG1 is connected to a sun gear, and the second rotary electric machine MG2 is connected to a ring gear. As a result, the engine 12, the first rotating electrical machine MG1, and the second rotating electrical machine MG2 are in a state of being always mechanically coupled. Further, the wheel 20 is connected to the power split mechanism 14 and the second rotary electric machine MG2 via the transmission 16. However, the mechanical connection between the wheel 20 and the power split mechanism 14 and the second rotating electric machine is released when the N range is selected as the shift range.

  The rotational force of the engine 12 is input to the planetary carrier and transmitted to the first rotary electric machine MG1 by the sun gear and to the second rotary electric machine MG2 and the wheel 20 by the ring gear. When stopping the engine 12 during rotation, kinetic energy of the rotation of the engine 12 is converted to electrical energy by the first rotary electric machine MG1 to reduce the rotational speed of the engine 12.

  The main battery 28 is a secondary battery that stores electric power necessary for the entire hybrid system, and is formed of, for example, a lithium ion battery. The main battery 28 supplies power to the rotary electric machine MG and the accessory battery 34. Further, main battery 28 is charged by the electric power generated by rotating electric machine MG.

  Charge and discharge of the main battery 28 are managed and controlled by the battery ECU 30. Information such as inter-terminal voltage, charge / discharge current, battery temperature and the like is input to the battery ECU 30 from a voltage sensor, a current sensor, and a temperature sensor (all not shown) provided in the main battery 28. The battery ECU 30 calculates the SOC (State Of Charge) of the main battery 28 based on these pieces of information, and transmits a signal representing the calculation result to the hybrid ECU 40.

  An SMR 26 and a transformer 24 are provided between the main battery 28 and the inverter 22. The transformer 24 boosts the power from the main battery 28 and sends it to the rotating electrical machine MG, and reduces the power generated by the rotating electrical machine MG to send it to the main battery 28. The SMR 26 electrically connects or disconnects the battery and the transformer 24. When the SMR 26 is turned on, charging / discharging of the main battery 28 is allowed, and the hybrid system becomes operable. Hereinafter, this SMR 26 is turned on, and a state where the hybrid system can operate is referred to as "Ready On". On the other hand, when the SMR 26 is turned off, charging / discharging of the main battery 28 is interrupted, and the entire hybrid system is stopped. Thereby, the engine 12 is also stopped. Hereinafter, the state in which the SMR 26 is turned off is referred to as "ready off".

  A step-down converter 32 is also provided between the transformer 24 and the SMR 26. The step-down converter 32 steps down the power from the main battery 28 and sends it to the accessory battery 34 and various accessories (for example, air conditioning etc.).

  The hybrid ECU 40 controls the engine ECU 38, the battery ECU 30, the SMR 26 and the inverter 22 according to the state of the hybrid vehicle 10, and controls the entire hybrid system so that the hybrid vehicle 10 can operate most efficiently. is there. In addition, the hybrid ECU 40 presents various information to the user via the information presentation unit 42 as needed. The information presentation unit 42 includes, for example, a display screen for displaying various images, a speaker for outputting sound, and the like. In the present embodiment, as will be described in detail later, warning information prompting a change of the shift range is presented via the information presentation unit 42.

  The hybrid ECU 40 receives the vehicle speed V detected by the vehicle speed sensor 36 and the shift range detected by the position sensor 44 provided on the shift lever, in addition to the SOC of the main battery 28 calculated by the battery ECU 30. The shift range selected by the user includes a D range selected when the vehicle is driven, a P range selected when the vehicle is parked, an R range selected when the vehicle is backed, and There is an N range or the like which is selected when the engine 12 and the wheel 20 are disconnected.

  When the D, R, and P ranges are selected as the shift range, the hybrid ECU 40 causes the first rotary electric machine MG1 to function as an electric motor to start the engine 12 when the SOC of the main battery 28 decreases. The inverter 22 is controlled so that the rotary electric machine MG1 functions as a generator. Thereby, the first rotary electric machine MG1 generates electric power by the power of the engine 12, and the main battery 28 is charged with the obtained electric power.

  In addition, when the hybrid ECU 40 generates regenerative power to charge the main battery 28 in a state where the D and R ranges are selected as the shift range, the inverter 22 is set such that the second rotary electric machine MG2 functions as a generator. Control. Thereby, kinetic energy of the vehicle is converted into electric energy by the second rotating electrical machine MG2.

  If N range is selected as the shift range, the driving force should not be transmitted to the wheel 20. Therefore, when the N range is selected, the mechanical connection between the engine 12 and the wheel 20 is released. Further, when the N range is selected, the rotary electric machine MG capable of driving the wheel 20 is in a state where the power is turned off. Specifically, when the N range is selected, the hybrid ECU 40 turns the switching element of the inverter 22 to the off state, and controls the rotating electrical machine MG to the stop state (non-driving state).

  Here, as is apparent from the above description, in the above-described hybrid vehicle 10, when the N range is selected, the rotary electric machine MG is in the stop state, and therefore, the main battery 28 is charged by the rotary electric machine MG. I can not On the other hand, even when the N range is selected, power is required to drive various accessories. Therefore, discharge from the main battery 28 is performed even during the N range selection. As a result, when the N range continues to be selected, the SOC of the main battery 28 gradually decreases.

  Here, usually, the main battery 28 is a secondary battery such as a lithium ion battery or a nickel hydrogen battery, but such a secondary battery is likely to be deteriorated when used in a state of low SOC. For example, in a lithium ion battery, when power is supplied in a low SOC state, an increase in internal resistance called high rate deterioration is promoted. The high rate deterioration is a deterioration caused by continuously supplying a relatively large current (high rate current) to the SOC, resulting in an increase in internal resistance. The early deterioration of the main battery 28 causes deterioration of fuel consumption, shortening of the replacement cycle of the main battery 28, and the like. Therefore, it is preferable to select the P range without selecting the N range as the shift range when the vehicle is at a stop. In the following, a state in which the N range is selected in a stopped state is referred to as "neutral stop".

  In some prior arts, in order to avoid such a problem, it is proposed to display a warning prompting a change to the P range when the SOC becomes less than a prescribed threshold when selecting the N range. According to this technology, when the SOC decreases to some extent, the P range is changed to enable power generation by the rotary electric machine MG. Then, since the main battery 28 is charged by the electric power generated by the rotary electric machine MG, the SOC is prevented from being excessively reduced.

  However, in the prior art, the warning is not displayed unless the SOC drops to some extent (SOC drops below the threshold). In other words, in the prior art, even if the N range is selected, the warning is not displayed when the SOC is high, and the user continues to maintain the state of the N range selection. Therefore, in the conventional technique, although the SOC is reduced for a short time, the deterioration of the main battery 28 can not be effectively suppressed. Of course, the transition to the low SOC state can be prevented by raising the threshold value of the SOC, which is a reference for displaying a warning. However, in this case, another problem arises that the warning is frequently output. In addition, simply raising the SOC threshold does not convey to the user the intention that the selection of the N range is undesirable when the vehicle is stopped. As a result, the user is confusing what to do to avoid the warning.

  Therefore, in the present embodiment, during the neutral stop, a warning that urges the change of the shift range is not based on the SOC of the main battery 28 but on the neutral stop duration Te or the integrated discharge current amount IIout during the neutral stop. I try to judge no. At this time, it is desirable to notify the user of the reason for notifying the warning, that is, the duration of the neutral stop Te is long or that the integrated discharge current amount IIout during the neutral period is large. With this configuration, the user can clearly recognize the cause of the warning and can recognize what to do to avoid the warning from now on.

  Next, the flow of the warning presentation process will be specifically described with reference to FIG. The hybrid ECU 40 first resets the two types of parameters serving as the basis of whether or not a warning is presented, the duration time Te, and the integrated discharge current amount IIout to zero (S10). Subsequently, the hybrid ECU 40 confirms whether the vehicle is Ready On, that is, whether the SMR 26 is in a travelable state (S12). If not, the hybrid ECU 40 returns to step S10. Further, at this time, if the measurement of the continuation time Te and the integrated discharge current amount IIout and the warning display have already been started, these are stopped (S24).

  On the other hand, if it is "Ready On", the hybrid ECU 40 subsequently confirms whether or not the neutral stop is in progress (S14). Specifically, the hybrid ECU 40 confirms the shift range and the vehicle speed. As a result of the check, if the vehicle is not in neutral stop, that is, if the shift range is other than the N range or the vehicle speed exceeds zero, the hybrid ECU 40 returns to step S10. At this time, if the measurement of the duration Te and the integrated discharge current amount ΣIout and the warning display have already been started, these are stopped (S24).

  On the other hand, if N range is selected as the shift range and the vehicle is in the neutral stop state where the vehicle speed is zero (stopped) (Yes in S14), the hybrid ECU 40 continues the neutral stop duration Te and the neutral stop period. The integrated value IIout of the discharge current amount is measured (S16). Then, the hybrid ECU 40 compares the measured continuation time Te with a predetermined reference time Tdef (S18). The reference time Tdef can be set to an arbitrary value, for example, several minutes to several tens of minutes. Further, the reference time Tdef may be a fixed value, or may be a variable value that changes according to the state of the vehicle and the surrounding environment. For example, the reference time Tdef may be smaller as the power consumption of the vehicle is higher. In addition, since the power consumption of the vehicle is likely to increase at night or at low temperatures, in such a case, the reference time Tdef may be reduced. Further, the reference time Tdef may be made smaller as the SOC of the main battery 28 is lower.

  If the continuation time Te is less than the reference time Tdef as a result of comparison between the continuation time Te and the reference time Tdef, the hybrid ECU 40 subsequently measures the integrated discharge current amount IIout that has been measured in advance as the predetermined reference current amount Idef. And (S20). The reference current amount Idef is also a value set arbitrarily. The reference current amount is determined according to the capacity of the main battery 28 and the like. The reference current amount Idef may also be a fixed value, or may be a variable value that changes according to the state of the vehicle and the surrounding environment. For example, the reference current amount Idef may be smaller as the battery temperature or the environmental temperature is lower. This is because high rate deterioration easily occurs when the battery temperature is low.

  If duration time Te is equal to or greater than reference time Tdef or integrated discharge current amount IIout is equal to or greater than reference current amount Idef (Yes in step S18 or Yes in step S20), hybrid ECU 40 issues a warning via information presenting unit 42. Is notified to the user (S22). The warning is not particularly limited as long as it prompts the user to change the shift range. Therefore, for example, a message or symbol prompting a change in shift range may be displayed on the display screen, or a message prompting a change in shift range may be output as voice. The shift range to be changed is not particularly limited as long as it is other than N range, and may be P range or D range. Not only the warning for prompting a change of the shift range, but also the reason (Te ≧ Tdef or IIout ≧ Idef) of the warning notification may be notified together. By notifying the reason of the warning notification, the user can recognize that it is important to avoid the neutral stop in order to avoid the occurrence of the warning.

  After notifying the warning, or when the result of step S18 or S20 is No, the hybrid ECU 40 returns to step S12. Then, after that, steps S12 to S22 are repeated until it becomes Ready Off (No in S12) or the neutral stop is ended (No in S14). During the control, if the Ready OFF (No in S12) or the neutral stop is ended (No in S14), the hybrid ECU 40 stops the measurement of the continuation time Te and the integrated discharge current amount IIout and the warning display (S24 ) And then return to step S10.

  As described above, in the present embodiment, when the duration Te of the neutral stop is long, or when the integrated discharge current amount IIout is large, a warning for prompting a shift range change is output. With this configuration, it is possible to urge change of the shift range regardless of the size of the SOC of the main battery 28. As a result, it is possible to effectively prevent the SOC of the main battery 28 from transitioning to a low level, and thus to effectively prevent the deterioration of the main battery 28.

  The configuration described so far is an example, and in the case of a neutral stop, if it outputs a warning prompting a change of the shift range when the duration Te is long or the integrated discharge current amount IIout is large, The configuration of may be changed as appropriate. For example, in the present embodiment, both the neutral stop duration Te and the integrated discharge current amount IIout are measured and compared with the reference value, but only one of them may be measured. Therefore, for example, only the duration Te of the neutral stop may be measured, and the integrated discharge current amount IIout may not be measured. Further, in addition to the duration Te and the integrated discharge current amount IIout, the SOC is also measured, and a warning to prompt the change of the shift range is output even when the SOC becomes less than a predetermined reference value. May be

DESCRIPTION OF SYMBOLS 10 hybrid vehicles, 12 engines, 14 power split mechanisms, 16 transmissions, 18 drive shafts, 20 wheels, 22 inverters, 24 transformers, 28 main batteries, 30 battery ECUs, 32 step-down converters, 34 accessory batteries, 36 vehicle speed sensors , 38 engine ECU, 40 hybrid ECU, 42 information presentation unit, 44 position sensor, MG1 first rotary electric machine, MG2 second rotary electric machine.

Claims (1)

An internal combustion engine,
A main battery that charges and discharges power,
One or more rotating electrical machines that generate power by functioning as a motor and generate power for charging the main battery by functioning as a generator;
A control device that shuts down the rotating electrical machine during a neutral stop where neutral is selected as a shift range in a stopped state;
Equipped with
Wherein the control device, if the duration of the neutral stop is Tsu Do a predefined threshold value or more hours, and outputs a warning for prompting a change of the shift range to the user, further, the duration is less than the threshold time even, if the accumulated amount of discharge current in the neutral stop is Tsu Do a predefined threshold amount of current or also outputs a warning for prompting a change of the shift range to the user,
A hybrid vehicle characterized by

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