JP2017140998A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle configured so that a main battery is hardly shifted into a low SOC state while the vehicle is stopped.SOLUTION: The hybrid vehicle is equipped with: an engine; a main battery which is charged with and discharged from electricity; one or more rotary electric machines that function as electric motors to generate power and function as electricity generators to generate electricity for charging the main battery; and a control device that shuts down the rotary electric machines during neutral stopping in which a neutral is selected as a shift range in a state where the vehicle is stopped. The control device outputs an alarm for prompting a user to change the shift range when duration Te of the neutral stopping is equal to prescribed reference time Tdef or more or accumulated discharged currents ΣIout during the neutral stopping are equal to prescribed threshold currents Idef or more.SELECTED DRAWING: Figure 2

Description

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

  Conventionally, hybrid vehicles having an engine and a rotating electric machine as power sources are widely known. Such a hybrid vehicle is equipped with a main battery for supplying electric power to a rotating electrical machine or the like. The rotating electrical machine functions as an electric motor that generates power by receiving power supply, and also functions as a generator that generates power by receiving power and regenerative torque from the engine. The electric power generated by the rotating electric machine is sent to the main battery, so that the main battery is charged.

  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 must not be transmitted to the wheel. Is turned off. When the power source of the rotating electrical machine is turned off, the main battery cannot be charged by the rotating electrical machine. On the other hand, electric power is required to drive an auxiliary machine or the like mounted on the vehicle. Therefore, during the N range selection, the main battery is only discharged without being charged. As a result, if the state in which the N range is selected while the vehicle is stopped for a long time, the SOC of the main battery decreases, and in some cases, the SOC may be exhausted.

JP 2008-094178 A

  Patent Document 1 discloses a technique for displaying a warning prompting the user to change the shift range if the SOC of the main battery decreases to a specified value or less in a state where the N range is selected while the vehicle is stopped in a hybrid vehicle. Is disclosed. According to such a technique, if the SOC decreases while the vehicle is stopped, the shift to a shift range (for example, a parking range or a drive range) in which the main battery can be charged is urged, so that exhaustion of SOC can be effectively prevented. .

However, the technique of Patent Document 1 prompts the change of the shift range only when the SOC of the main battery decreases. In other words, in the technique of Patent Document 1, when the SOC of the main battery is high, no warning is displayed even if the N range is selected and the vehicle is stopped.
Therefore, the user cannot recognize a 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, the SOC is likely to change to a low state while the vehicle is stopped.

  Therefore, an object of the present invention is to provide a hybrid vehicle in which the main battery is unlikely to shift to a low SOC state when the vehicle is stopped.

  The hybrid vehicle of the present invention generates power by functioning as an internal combustion engine, a main battery that charges and discharges electric power, and functions as an electric motor, and generates electric power for charging the main battery by functioning as a generator. One or more rotating electrical machines, and a control device that shuts down the rotating electrical machines during a neutral stop in which neutral is selected as a shift range in a stopped state, and the control device has a duration of neutral stopping Is output to the user when a predetermined threshold time is exceeded or the accumulated discharge current amount during the neutral stop is equal to or greater than a predetermined threshold current amount. It is characterized by.

  According to the present invention, a warning is output when the neutral stop duration or the accumulated discharge current amount during the neutral period is large regardless of the SOC. As a result, the main battery is unlikely to transition to a low SOC state.

It is a figure which shows the structure of the hybrid vehicle which is embodiment of this invention. It is a flowchart which shows the flow of a warning presentation process.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a 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 there is no need to distinguish between the first rotating electrical machine MG1 and the second rotating electrical machine MG2, they are simply referred to as “rotating electrical machine MG”.

  The engine 12 is an internal combustion engine that outputs power using a 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 control the operation of the engine 12, parameters detected by various sensors (not shown) such as a pressure value in the fuel quality, an air-fuel ratio, an intake air amount, and the like are input to the engine ECU 38.

  The rotating electrical machine MG functions as a generator or functions as an electric motor according to the traveling state of the hybrid vehicle 10. Regenerative braking is performed when this rotating electrical machine MG functions as a generator. The first rotating electrical machine MG1 mainly functions as a generator, and generates electric power using power from the engine 12. The first rotating electrical machine MG1 also functions as an electric motor (starter motor) that starts the engine. Second rotating electrical machine MG2 mainly functions as an electric motor and outputs motive power for traveling of the vehicle. The second rotating electrical machine MG2 also functions as a generator, and performs so-called regenerative power generation that decelerates the vehicle by converting the kinetic energy of the vehicle into electric energy. The inverter 22 performs current control between the main battery 28 and the rotating electrical machine MG while converting electric 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 the inverter 22 is turned off and the rotating electrical machine MG is stopped (non-driven state). )

  The power generated by the engine 12 and the rotating electrical machine MG is transmitted to the wheels 20 via the drive shaft 18 and the 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 that includes a planetary carrier, a sun gear, and a ring gear in order to distribute the power of the engine 12 to both the wheels 20 and the first rotating electrical machine MG1. Engine 12 is connected to a planetary carrier, first rotating electrical machine MG1 is connected to a sun gear, and second rotating electrical 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 mechanically always coupled. The wheels 20 are connected to the power split mechanism 14 and the second rotating electrical machine MG2 via the transmission 16. However, the mechanical connection between the wheel 20 and the power split mechanism 14 and the second rotating electrical 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, which is transmitted to the first rotating electrical machine MG1 by the sun gear and to the second rotating electrical machine MG2 and the wheel 20 by the ring gear. When the rotating engine 12 is stopped, the kinetic energy of the rotation of the engine 12 is converted into electric energy by the first rotating electrical machine MG1, and the rotational speed of the engine 12 is reduced.

  The main battery 28 is a secondary battery that stores electric power necessary for the entire hybrid system, and is composed of, for example, a lithium ion battery. The main battery 28 supplies power to the rotating electrical machine MG and the auxiliary battery 34. Moreover, the main battery 28 is charged with the electric power generated by the rotating electrical machine MG.

  The charging / discharging of the main battery 28 is managed and controlled by the battery ECU 30. Information such as a voltage between terminals, a charge / discharge current, and a battery temperature 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 steps down the power generated by the rotating electrical machine MG and sends 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 permitted, and the hybrid system can be operated. Hereinafter, a state in which the SMR 26 is turned on and 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 cut off, 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 further 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 auxiliary battery 34 and various auxiliary machines (for example, air conditioner).

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

  In addition to the SOC of the main battery 28 calculated by the battery ECU 30, 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. 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 selected when the engine 12 and the wheel 20 are separated.

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

  Further, when the hybrid ECU 40 generates regenerative power and charges the main battery 28 with the D and R ranges selected as the shift range, the hybrid ECU 40 sets the inverter 22 so that the second rotating electrical machine MG2 functions as a generator. Control. Thereby, the kinetic energy of the vehicle is converted into electric energy by the second rotating electrical machine MG2.

  When the N range is selected as the shift range, the driving force must not be transmitted to the wheels 20. Therefore, when the N range is selected, the mechanical connection between the engine 12 and the wheel 20 is released. When the N range is selected, the rotating electrical machine MG that can drive the wheels 20 is turned off. Specifically, when the N range is selected, hybrid ECU 40 turns off the switching element of inverter 22 and controls rotating electric machine MG to a stopped state (non-driven state).

  Here, as is apparent from the above description, in the above-described hybrid vehicle 10, when the N range is selected, the rotating electrical machine MG is stopped, and thus the main battery 28 is charged by the rotating electrical machine MG. I can't. On the other hand, even when the N range is selected, electric power is required to drive various auxiliary machines. Therefore, even when the N range is selected, the main battery 28 is discharged. As a result, when the state where the N range is selected continues, the SOC of the main battery 28 gradually decreases.

  Here, the main battery 28 is usually a secondary battery such as a lithium ion battery or a nickel metal hydride battery. However, such a secondary battery tends to deteriorate when used in a state where the SOC is low. For example, in a lithium ion battery, when energized in a low SOC state, an increase in internal resistance called high rate deterioration is promoted. High-rate deterioration is deterioration that occurs when a relatively large current (high-rate current) is continuously applied to the SOC and causes 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 can be said that it is desirable to select the P range without selecting the N range as the shift range when the vehicle is stopped. Hereinafter, the state where the N range is selected while the vehicle is stopped is referred to as “neutral stop”.

  In order to avoid such a problem, some prior arts have proposed to display a warning prompting the user to change to the P range when the SOC is equal to or less than a predetermined threshold when the N range is selected. According to such a technique, when the SOC is lowered to some extent, it is changed to the P range and power generation by the rotating electrical machine MG becomes possible. And since the main battery 28 is charged with the electric power generated by the rotating electrical machine MG, the SOC is prevented from excessively decreasing.

  However, in the conventional technique, the warning is not displayed unless the SOC is lowered to some extent (SOC is lowered to a threshold value or less). In other words, in the conventional technique, even if the N range is selected, a warning is not displayed in a state where the SOC is high, and thus the user has continued to maintain the N range selected state. For this reason, in the conventional technology, although the SOC is lowered in a short time, the deterioration of the main battery 28 cannot be effectively suppressed. Of course, the transition to the low SOC state can be prevented by increasing the SOC threshold value that serves as a reference for displaying the warning. However, in that case, another problem that a warning is output with high frequency is caused. Further, simply increasing the SOC threshold value does not convey to the user the intention that selection of the N range is not desirable when the vehicle is stopped. As a result, it is difficult for the user to know what to do to avoid the warning.

  Therefore, in the present embodiment, during the neutral stop, a warning that prompts the change of the shift range is required based on the neutral stop duration Te or the accumulated discharge current amount ΣIout during the neutral stop, not the SOC of the main battery 28. I try to judge no. At this time, it is desirable to notify the user of the reason for notifying the warning, that is, that the duration Te of the neutral stop is long or the accumulated discharge current amount ΣIout during the neutral period is large. With this configuration, the user can clearly recognize the cause of the warning, and can recognize what should be done in order to avoid the warning in the future.

  Next, the flow of the warning presentation process will be specifically described with reference to FIG. First, the hybrid ECU 40 resets the values of the two types of parameters, ie, the duration time Te and the integrated discharge current amount ΣIout, which serve as a reference for whether or not to present a warning, to zero (S10). Subsequently, the hybrid ECU 40 checks whether or not the vehicle is Ready On, that is, whether or not the vehicle is in a travelable state with the SMR 26 turned on (S12). If not Ready On, the hybrid ECU 40 returns to step S10. At this time, if the measurement of the duration time Te and the accumulated discharge current amount ΣIout 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 checks whether or not the vehicle is in a neutral stop (S14). Specifically, the hybrid ECU 40 checks the shift range and the vehicle speed. As a result of the confirmation, when the vehicle is not in the neutral stop state, that is, when 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 time 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 the N range is selected as the shift range and the vehicle speed is zero (stopped) and the vehicle is in a neutral stop state (Yes in S14), the hybrid ECU 40 determines the duration time Te of the neutral stop and the neutral stop period. The discharge current amount integrated value ΣIout is measured (S16). Then, the hybrid ECU 40 compares the measured duration time Te with a predefined reference time Tdef (S18). The reference time Tdef is a value that is arbitrarily set, and can be, for example, several minutes to several tens of minutes. Further, the reference time Tdef may be a fixed value, but may be a variable value that varies depending on the state of the vehicle and the surrounding environment. For example, the reference time Tdef may be made smaller as the power consumption in the vehicle is higher. Further, since the power consumption of the vehicle tends to increase at night or at low temperatures, the reference time Tdef may be reduced in such a case. Further, the reference time Tdef may be reduced as the SOC of the main battery 28 is lower.

  As a result of the comparison between the duration time Te and the reference time Tdef, if the duration time Te is less than the reference time Tdef, the hybrid ECU 40 subsequently uses the measured cumulative discharge current amount ΣIout as a predetermined reference current amount Idef. (S20). The reference current amount Idef is also an arbitrarily set value. 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, but 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 made smaller as the battery temperature or the environmental temperature is lower. This is because high rate deterioration tends to occur when the battery temperature is low.

  If the duration time Te is equal to or greater than the reference time Tdef or the accumulated discharge current amount ΣIout is equal to or greater than the reference current amount Idef (Yes in step S18 or Yes in step S20), the hybrid ECU 40 warns via the information presentation 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 a pattern for urging the change of the shift range may be displayed on the display screen, or a message for urging the change of the shift range may be output as a voice. The shift range to be changed is not particularly limited as long as it is other than the N range, and may be the P range or the D range. Further, not only the warning prompting the change of the shift range but also the reason for the warning notification (Te ≧ Tdef or ΣIout ≧ Idef) may be notified together. By notifying the reason for the warning notification, the user can recognize that it is important to avoid the neutral stop in the future in order to avoid the occurrence of the warning.

  The hybrid ECU 40 returns to step S12 after notifying the warning or when the answer is No in both steps S18 and S20. Thereafter, Steps S12 to S22 are repeated until Ready Off (No in S12) or until the neutral stop is completed (No in S14). In the middle of the control, when it becomes Ready Off (No in S12) or the neutral stop is completed (No in S14), the hybrid ECU 40 stops the measurement of the duration Te and the integrated discharge current amount ΣIout and the warning display (S24). ) And return to step S10.

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

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

DESCRIPTION OF SYMBOLS 10 Hybrid vehicle, 12 Engine, 14 Power split mechanism, 16 Transmission, 18 Drive shaft, 20 Wheel, 22 Inverter, 24 Transformer, 28 Main battery, 30 Battery ECU, 32 Step-down converter, 34 Auxiliary battery, 36 Vehicle speed sensor , 38 engine ECU, 40 hybrid ECU, 42 information presentation unit, 44 position sensor, MG1 first rotating electrical machine, MG2 second rotating electrical 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 an electric motor and generate electric 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;
With
When the duration of the neutral stop is equal to or greater than a predetermined threshold time, or the accumulated discharge current amount during the neutral stop is equal to or greater than a predetermined threshold current amount, the control device Output a warning prompting the user to change the range,
A hybrid vehicle characterized by that.

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