JP6471860B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a control device for a hybrid vehicle including a traveling motor and a generator driven by an engine.

  In recent years, hybrid vehicles in which a driving motor and an engine are combined to obtain a driving force of the vehicle have been developed and put into practical use. As a hybrid vehicle, not only a vehicle (PHV) that charges a battery that drives a generator by an engine to generate electricity and supplies power to a traveling motor but also a battery (PHEV) that can be charged by an external commercial power source is also used. Development and practical use are progressing.

  In such a hybrid vehicle, an EV mode in which driving wheels are driven by using only a traveling motor as a power source, and a generator is driven by an engine while the traveling motor is used as a power source, and electric power is supplied to the battery and the traveling motor. There is known a series mode to be supplied, or a parallel mode in which both the engine and the traveling motor are used as power sources, depending on the driving situation.

  In the hybrid vehicle, the generator is driven by the operation of the engine, and the generated power is charged in the battery. When driving the generator, the target engine rotation speed and engine torque are set according to the required power generation power, the engine is controlled to achieve the desired generated power, the generator is driven, and constant power generation Electric power is obtained (see, for example, Patent Document 1). Therefore, the engine can be operated with good fuel consumption efficiency to obtain desired generated power.

  By the way, in the high state area | region where the charge ratio of a battery exceeds a predetermined charge ratio, the electric power of charge required is little. For this reason, when charging is performed in an area where the charging rate of the battery is higher than the predetermined charging rate, when the engine is operated with good fuel consumption efficiency at the target engine rotation speed and engine torque, charging is performed. In addition, it is conceivable that a large amount of current flows due to an increase in power supply to the battery. If too much current flows, there is a risk that the voltage becomes too high and a large burden is placed on the battery.

JP 2003-9305 A

  The present invention has been made in view of the above situation, and a control device for a hybrid vehicle in which when the engine is operated with good fuel consumption efficiency to generate electric power, the voltage becomes too high and a large burden is not caused on the battery. The purpose is to provide.

In order to achieve the above object, a control apparatus for a hybrid vehicle according to a first aspect of the present invention includes a travel motor that transmits driving force to drive wheels, a battery that supplies electric power to the travel motor, and an engine operation. A hybrid vehicle control device having a generator for generating required power including at least electric power to be supplied to the battery, the charging status detection means for detecting the charging status of the battery, and the engine Fuel efficiency point deriving means for obtaining an operating point with good fuel consumption efficiency based on the rotational speed and torque, and operating the engine so that the generated power increases with respect to the required power, whereby the fuel efficiency point deriving means a power generation control means for controlling the power generation of the generator by operating the engine on the basis of the obtained operating point determined by the running of the hybrid vehicle And a high degree detecting means for detecting the altitude of the place, the power generation control unit, when the charging rate detected by said charging state detection means is less than a predetermined charging rate, perform the power generation control of the generator, the The amount of increase in the generated power when the altitude of the traveling location of the hybrid vehicle detected by the altitude detecting means is higher than the standard altitude is smaller than the amount of increase in the generated power at the standard altitude. Reduce the amount of increase in the generated power per unit time when the altitude is higher than the standard altitude, and set the slope of the change over time in the charging rate when charging when the altitude is higher than the standard altitude. It is characterized by being made smaller than the standard altitude .
When the altitude of the driving location is higher than the standard altitude, the engine speed needs to be high in order to obtain the same output or generated power as the standard altitude.
.

According to the first aspect of the present invention, the engine is operated to control the power generation of the generator so that the generated power is increased with respect to the required power in accordance with the operating state of the hybrid vehicle. In this case, the power generation control of the generator is executed when the charging rate detected by the charging status detecting means is equal to or lower than a predetermined charging rate. When the battery charge rate is less than or equal to the specified charge rate, the engine operating point is optimally changed to adjust the generated power.If the battery charge rate exceeds the specified charge rate, the engine operation is stopped. Thus, power generation control can be performed by shortening the engine operation time (e.g., increasing the travel time of the travel motor), such as supplying power from the battery to the travel motor. Thereby, charging in a state where a large amount of current flows and the voltage becomes high can be suppressed.
The power generation control means is set so that the amount of increase in the generated power in the highland is less than the lowland (flat land) which is the standard altitude. Therefore, when the traveling place is the highland, the lowland (flat ground) In contrast, the generated electric power is suppressed, and the engine speed is lowered so that noise caused by the engine speed can be suppressed.
When the driving location is higher than the lowland (flat land), the amount of increase in the generated power is set to be small, so the increase in the charge rate per unit time is small, and the charge rate is charged at the highland. The slope of the change over time is smaller than when the ground is low (flat).

  In other words, when the battery charge rate is higher than the predetermined charge rate, the engine is operated so that the required power for charging (required power) is small and the generated power increases in a region where the power required for charging is low. When charging is performed, it is conceivable that the supply of power to the battery increases and a large amount of current flows. If too much current flows, the voltage will become too high and a heavy burden will be placed on the battery.However, since the charging rate of the battery is higher than the specified charging rate and charging can not be performed, the voltage becomes too high. Thus, it is possible to suppress a large burden on the battery.

  For this reason, when the engine is operated with good fuel consumption efficiency, that is, when generating power by operating the engine at an operating point with good fuel consumption efficiency by increasing the generated power with respect to the required power, the voltage is high. Therefore, it is possible to eliminate a large burden on the battery due to becoming too much.

A hybrid vehicle control device according to a second aspect of the present invention is the hybrid vehicle control device according to the first aspect , wherein the power generation control means uses the travel motor as a travel power source of the hybrid vehicle. In addition, power generation control of the generator is executed in a series mode in which the generator is driven by the engine and power is supplied to at least one of the battery and the travel motor.

According to the second aspect of the present invention, when the power generation is performed according to the engine rotation speed and the engine torque in the series mode, it is possible to eliminate a large burden on the battery due to the voltage becoming too high.

  The control device for a hybrid vehicle of the present invention operates the engine with good fuel consumption efficiency, that is, generates power by operating the engine at an operating point with good fuel consumption efficiency by increasing the generated power with respect to the required power. In doing so, it is possible to eliminate a significant burden on the battery due to the voltage becoming too high.

1 is an overall schematic configuration diagram of a hybrid vehicle equipped with a control device according to an embodiment of the present invention. It is a block block diagram for performing power generation control. It is a map explaining the operating point of generated electric power. It is a map explaining the relationship between vehicle speed and generated electric power (required electric power). It is a graph explaining the time-dependent change of the charge ratio (power generation control) at the time of acceleration. It is a graph explaining the time-dependent change of the charge ratio (power generation control) at the time of deceleration. It is a graph explaining the time-dependent change of the charge ratio (power generation control) in a lowland and a highland. It is a flowchart of electric power generation control.

The overall configuration of the hybrid vehicle will be described with reference to FIG. FIG. 1 shows an overall schematic configuration of a hybrid vehicle equipped with a control device according to an embodiment of the present invention.
As shown in the figure, a hybrid vehicle (vehicle) 1 is provided with a traveling motor 3 that transmits power to the drive wheels 2 and an engine 4. The driving force of the traveling motor 3 is transmitted to the driving wheel 2 via the transmission mechanism 5. A battery 7 is connected to the traveling motor 3 via a circuit 6 such as an inverter. Electric power corresponding to the passenger's pedal operation is supplied from the battery 7 to the traveling motor 3 via the circuit 6.

  A generator 9 is connected to the engine 4 via an output system 8, and the generator 9 is connected to a battery 7 (and a traveling motor 3) via a circuit 6. The output system 8 is connected to the generator 9 while being connected to the transmission mechanism 5 via the clutch 10.

  When the engine 4 is operated according to the driving state of the vehicle 1, the driving force of the engine 4 is transmitted to the generator 9 via the output system 8. The generator 9 is rotated (driven) by the operation of the engine 4 to generate power. The electric power generated by the generator 9 is supplied to the battery 7 and the traveling motor 3. When the output system 8 and the transmission mechanism 5 are connected by the clutch 10 according to the driving state of the vehicle 1, the driving force of the engine 4 is transmitted to the generator 9 and the driving wheels 2.

  The vehicle 1 is provided with a control device 11 that comprehensively controls various devices. Information about the rotational speed of the engine 4 and information about the vehicle speed sensor 12 are input to the control device 11. The vehicle 1 is provided with a charging status detection unit 15 that detects a charging status (charging ratio: SOC) of the battery 7, and information on the charging status detection unit 15 is input to the control device 11. Further, the vehicle 1 is provided with an accelerator position sensor (APS) 13 as required torque detection means, and detection information (requested torque information) of the APS 13 is input to the control device 11. Further, the vehicle 1 is provided with an atmospheric pressure measuring unit 14 as an altitude detecting unit, and detection information of the atmospheric pressure measuring unit 14 is input to the control device 11.

  As the required torque detection means, means for deriving the required torque based on the rotational speed of the traveling motor 3 can be used instead of (in addition to) the accelerator position sensor (APS) 13.

  The vehicle 1 having the above configuration has an EV mode in which the travel motor 3 is a power source for vehicle travel, and a series mode in which the travel motor 3 is used as a power source for vehicle travel and the engine 4 is used as a power source for the generator 9. doing. Furthermore, it has a parallel mode in which the traveling motor 3 and the engine 4 are used as a power source for traveling the vehicle. Each operation mode is appropriately selected and switched according to the traveling state of the vehicle 1.

The hybrid vehicle control device according to the embodiment of the present invention is characterized by, for example, power generation control of the generator 9 during operation in the series mode. The power generation control according to one embodiment of the present invention will be specifically described with reference to FIGS.
FIG. 2 is a block diagram for performing power generation control of a hybrid vehicle control device according to an embodiment of the present invention, and FIG. 3 is a map for explaining operating points of generated power in relation to engine torque and rotational speed. 4 is a map for explaining the relationship between the vehicle speed and the generated power (required power), FIG. 5 is a change with time in the charge ratio during acceleration (change with time in power generation control), and FIG. 6 is a charge ratio during deceleration. FIG. 7 shows the change with time (change with time in power generation control) of the charging ratio in traveling in the lowland (flat area) and highland. FIG. 8 shows a flowchart for explaining an example of the power generation control process in the hybrid vehicle control apparatus according to the embodiment of the present invention.

  As shown in FIG. 2, detection information of the APS 13, detection information of the atmospheric pressure measurement unit 14, and detection information of the charging status detection unit 15 are input to the control device 11. The control device 11 is provided with fuel efficiency point deriving means 21 for obtaining an operating point with good fuel consumption efficiency based on the rotational speed and torque of the engine 4. Further, the control device 11 is provided with power generation control means 22 for operating the engine 4 according to the required power for power generation, and the engine 4 is configured so that the generated power increases according to the operating state of the vehicle 1 (see FIG. 1). Is provided with an increase amount setting function 23.

  The fuel efficiency point deriving means 21 stores the map shown in FIG. As shown in FIG. 3, the region where the fuel consumption efficiency is good due to the relationship between the torque and the rotational speed of the engine 4 is, for example, equal fuel consumption lines P1, P2, and P3 (lines connecting the same fuel consumption efficiency: The fuel efficiency of P1 <the fuel efficiency of P2 <the fuel efficiency of P3). And, for example, an operating point S with good fuel efficiency of the engine 4 when generating electric power of generated power x0kW, x1kW, x2kW, x3kW (x0 <x1 <x2 <x3) indicated by a one-dot chain line in the figure (solid line in the figure) Is set).

Based on the map shown in FIG. 3, the generated power is increased according to the driving state of the vehicle 1. As a result, the operation of the engine 4 is controlled by the rotational speed and torque of the operating point S with good fuel consumption efficiency, and the generator 9 is driven to generate necessary power (power generation control means 22).
The increase amount setting function 23 generates power when the torque required for the engine 4 (derived based on the detection information of the APS 13) is in an acceleration state (slow acceleration state and steady state) as compared with that in a deceleration state. A function for setting a large amount of increase is provided. That is, the increase amount setting function 23 stores the map shown in FIG. As shown by a dotted line in FIG. 4, a reference required power is set according to the vehicle speed, and the generated power in the acceleration state (slow acceleration state and steady state) and the deceleration state according to the required torque. Is set to increase. When the required torque is in the accelerated state (slowly accelerating state and steady state) (shown by a solid line in FIG. 4), the generated power is lower than that in the decelerating state (shown by a one-dot chain line in FIG. 4). A large amount of increase is set.

  For example, when the reference required power is x0 kW and the engine 4 is operated in a region outside the equal fuel consumption line P1 (region outside P1 where fuel consumption efficiency is low) in the map shown in FIG. Becomes lower than P1, and the operation is performed in a region where the fuel consumption efficiency is not good. In this embodiment, the generated power is increased according to the operating state, and the generated power is increased in the acceleration state (slow acceleration state and steady state) and the deceleration state according to the required torque. 3 is increased to x1 kW and x2 kW, and the engine 4 is operated in the region inside the equal fuel consumption lines P2 and P3 in the map shown in FIG. 3, and the operation is performed in the region where the fuel consumption efficiency is good.

  And, in the acceleration state (slow acceleration state and steady state), the amount of increase in the generated power is set larger than in the deceleration state, so in the acceleration state (slow acceleration state and steady state) When the engine 4 is operated so as to increase the generated power and is in a deceleration state, the engine 4 is operated in a state in which the increase in generated power is suppressed and the increase in noise is suppressed. The engine can be operated to generate electricity at an operating point with good fuel consumption efficiency.

  Specifically, as will be described later, when the torque required for the vehicle 1 is in an acceleration state (slow acceleration state and steady state) compared to when the vehicle is in a deceleration state, the amount of increase in generated power is set larger. In the acceleration state, the slope of the change over time during charging of the charge ratio becomes larger than the slope of the change over time during charging during the deceleration state.

  Then, the power generation control means 22 operates the engine 4 based on the map shown in FIG. 3 when the SOC detected by the charge status detection means 15 is less than or equal to a predetermined charge ratio (for example, only when it is 30% or less). . That is, power generation control of the generator 9 (see FIG. 1) is executed only when the SOC of the battery 7 is equal to or lower than a predetermined charging rate.

  That is, as shown in FIGS. 5 and 6, the SOC of the battery 7 (see FIG. 1) decreases with traveling by the traveling motor 3 (see FIG. 1), and the SOC becomes a predetermined charging rate S <b> 1 or less. For example, when the charging rate S2 decreases by several percent (time t1), the engine 4 (see FIG. 1) is operated to perform charging. When the SOC is equal to or lower than the predetermined charging rate S1, charging and discharging are repeated between the predetermined charging rate S1 and the charging rate S2.

  As described above, since the amount of increase in the generated power is set more when the torque required for the vehicle 1 is in the acceleration state (slow acceleration state and steady state) than in the deceleration state, FIG. In the acceleration state shown (slow acceleration state and steady state), the amount of increase in the charge rate per unit time is larger than that in the deceleration state shown in FIG. . For this reason, the slope of change over time during charging of the charging rate in the acceleration state (see FIG. 5) is larger than the slope of change over time of charging during the deceleration state (see FIG. 6). ing.

In the region where the SOC of the battery 7 is equal to or less than the predetermined charging rate S1, the operation of the engine 4 is stopped and the electric power is continuously supplied from the battery 7 to the traveling motor 3 until the SOC reaches the charging rate S2. Even in the region where the charging ratio is not more than the predetermined charging ratio S1, the power generation control can be performed by shortening the operation time of the engine 4 (increasing the travel time of the travel motor 3).
And in the state where SOC of the battery 7 is high exceeding the predetermined charging rate S1, it is possible to suppress power generation in a state where a large amount of current flows and the voltage of the battery 7 becomes high.

  When the SOC of the battery 7 is less than the predetermined charging rate S1, the required charging power (required power) is small, and the operation of the engine 4 for generating the required power is performed at a low rotational speed and low torque. There is a risk of driving in a region where the fuel consumption efficiency is low. In the present embodiment, when the SOC of the battery 7 is equal to or less than the predetermined charging rate S1, power generation is performed by optimally changing the operating point of the engine 4 and adjusting the generated power, so that the fuel consumption efficiency is low. The operation of the engine 4 can be suppressed.

  In addition, when charging is performed in a region where the SOC of the battery 7 is higher than the predetermined charging rate S1, that is, in a region where the required power is low, the supply of power to the battery 7 increases and a large amount of current flows. It is possible. If too much current flows through the battery 7, the voltage becomes too high, causing a heavy burden on the battery 7. In the present embodiment, since charging cannot be performed in a state where the charging rate of the battery 7 is higher than the predetermined charging rate S1, it is possible to suppress a large burden on the battery 7 due to excessive voltage. .

  In the increase amount setting function 23, when the altitude of the travel location of the vehicle 1 (derived based on the detection information of the atmospheric pressure measuring means 14) is higher than the standard altitude (when the altitude is low) (when the altitude is high) ) Has a function of setting the amount of increase in the generated power to be smaller than the amount of increase in the generated power when the ground is low. When the altitude of the travel location of the vehicle 1 is higher than the reference altitude, that is, when the travel location is high, the engine rotation speed is high in order to obtain the same output as the low ground or generated power. Need speed.

  In this embodiment, since the amount of increase in the generated power is set to be lower than that in the lowland when the land is high, power generation is performed on the lowland when the traveling place is highland. Electric power is suppressed, and noise caused by engine speed can be suppressed.

  As shown in FIG. 7, when the SOC of the battery 7 decreases and the SOC is equal to or lower than the predetermined charging rate S1, charging and discharging are repeated between the predetermined charging rate S1 and the charging rate S2. When the travel location is higher than the lowland, the amount of increase in the generated power is set to be small, so that the increase in the charging rate per unit time is smaller than that in the lowland. For this reason, the slope of change over time during charging of the charging rate in the case of high altitude (shown by a two-dot chain line in the figure) is the time-dependent change during charging of the reference charging rate (charging rate in the case of low altitude). It is smaller than the inclination (shown by a solid line in the figure).

A process of an example of power generation control in the above-described hybrid vehicle control device will be described with reference to FIG.
The required power is set according to the power for driving the vehicle 1, the charging power of the battery 7, and the power consumption of the auxiliary machine, and power generation is performed according to the required power depending on the driver's direct intention and the driving state of the vehicle 1. Is done. For example, the engine 4 is driven to charge the battery 7 by an operation to charge the driver or when the vehicle 1 (battery 7) is in a state where charging is forcibly required. It is then determined whether the charging mode is set.

  When the process starts, it is determined in step S5 whether or not the SOC of the battery 7 is equal to or less than a predetermined charging rate S1. If it is determined in step S5 that the SOC of the battery 7 exceeds the predetermined charging rate S1, the SOC is high in a state that is not in the charge mode, so that the engine does not require power generation by 4 (EV traveling). End.

  If it is determined in step S5 that the SOC of the battery 7 is equal to or lower than the predetermined charging rate S1, that is, if it is determined that the state is equal to or lower than the predetermined charging rate S1 in FIGS. 5 and 6, the required torque is determined in step S6. Is in an acceleration state (slow acceleration state and steady state). That is, based on the required torque of the vehicle 1 derived based on the detection information of the APS 13, it is determined whether or not the required torque is in an acceleration state (slow acceleration state and steady state).

  If it is determined in step S6 that the required torque is in the acceleration state (slow acceleration state and steady state), charging corresponding to the generated power in the acceleration state is set in step S7. That is, the amount of increase in the acceleration state set in advance (compared to that in the deceleration state) so that charging is started from time t1 (charging ratio S2) when the time until the required torque of the vehicle 1 is determined. The generated power is set with a large increase amount (see FIGS. 3 and 4).

  In step S8, the upper limit of the SOC is set (predetermined charging rate S1). In step S3, a request for operation is output to the engine 4 so that the generated power is in an accelerated state. . By repeating the process. When the SOC is equal to or lower than the set upper limit (predetermined charge rate S1), charging and discharging are repeated between the predetermined charge rate S1 and the charge rate S2 (see FIG. 5).

  If it is determined in step S6 that the vehicle 1 is not in an accelerated state (slowly accelerating state and steady state), that is, in a decelerating state, charging corresponding to the generated power in the decelerating state is set in step S9. That is, the amount of increase in the deceleration state set in advance (compared to that in the acceleration state) so that charging is started from time t1 (charge ratio S2) when the time until the required torque of the vehicle 1 is determined. The generated power is set with a small increase amount (see FIGS. 3 and 4).

  In step S8, the upper limit of the SOC is set (predetermined charging rate S1). In step S3, an operation request is output to the engine 4 so that the generated power is in a decelerated state, and the generator 9 generates power and ends. . By repeating the process. When the SOC is equal to or lower than the set upper limit (predetermined charge rate S1), charging and discharging are repeated between the predetermined charge rate S1 and the charge rate S2 (see FIG. 6).

  In the charge setting in step S7 and step S9, when the traveling place is highland, the generated power is suppressed with respect to the lowland, and the rotational speed of the engine 4 is lowered, resulting in the engine rotational speed. The generated power is adjusted to suppress noise. That is, for each of the generated power in the accelerated state and the generated power in the decelerated state, the amount of increase in the generated power is adjusted to be smaller when the travel location is higher than the low ground (see FIG. 7). .

  The above-described hybrid vehicle control device controls the power generation of the generator 9 by operating the engine 4 so that the generated power increases with respect to the required power depending on the driving state of the vehicle 1. It is possible to drive at an efficient operating point. In this case, the power generation control of the generator 9 is performed when the SOC detected by the charging status detection means 15 is equal to or less than the predetermined charging rate S1, and the generated power is adjusted by optimally changing the operating point of the engine 4. Therefore, in a region where the electric power required for charging is small, the supply of electric power to the battery does not increase so that a large amount of current does not flow, and the voltage becomes too high to cause a large burden on the battery 7. .

  Therefore, when generating power by operating the engine 4 at an operating point with good fuel consumption efficiency by increasing the generated power with respect to the required power, the voltage becomes too high and a large burden is not caused on the battery 7. Can do.

  In the above-described embodiment, the amount of increase in the generated power is set more in the acceleration state (slow acceleration state and steady state) than in the deceleration state of the vehicle 1, but in the deceleration state and acceleration state. It is also possible to increase the same amount. It is also possible to increase the generated power by the same amount in the lowland (flat land) and highland.

  INDUSTRIAL APPLICABILITY The present invention can be used in the industrial field of hybrid vehicle control devices including a travel motor and a generator driven by an engine.

1 Hybrid vehicle (vehicle)
DESCRIPTION OF SYMBOLS 2 Drive wheel 3 Driving motor 4 Engine 5 Transmission mechanism 6 Circuit 7 Battery 8 Output system 9 Generator 10 Clutch 11 Control device 12 Vehicle speed sensor 13 Acceleration position sensor (APS)
14 Atmospheric pressure measurement means 15 Charging status detection means 21 Fuel efficiency point deriving means 22 Power generation control means 23 Increase amount setting function

Claims (2)

A traveling motor that transmits driving force to the driving wheels;
A battery for supplying electric power to the traveling motor;
A control device for a hybrid vehicle, which is driven by the operation of an engine and has a generator for generating required power including at least power to be supplied to the battery,
Charging status detection means for detecting the charging status of the battery;
Fuel efficiency point deriving means for obtaining an operating point with good fuel consumption efficiency based on the rotational speed and torque of the engine;
By operating the engine so that the generated power increases with respect to the required power, the engine is operated based on the operating point obtained by the fuel efficiency point deriving means to control the power generation of the generator. Power generation control means ;
Altitude detecting means for detecting the altitude of the travel location of the hybrid vehicle,
The power generation control means includes
When the charging rate detected by the charging status detection means is equal to or lower than a predetermined charging rate, the power generation control of the generator is executed ,
The increase amount of the generated power when the altitude of the traveling location of the hybrid vehicle detected by the altitude detection means is higher than the reference altitude is larger than the increase amount of the generated power at the reference altitude. Set less,
The amount of increase in the generated power per unit time when the altitude is higher than the standard altitude is reduced, and the slope of the change over time in the charging rate when charging when the altitude is higher than the standard altitude A control device for a hybrid vehicle, which is smaller than that at an altitude . In the hybrid vehicle control device according to claim 1 ,
The power generation control means includes
In the series mode in which the driving motor is used as a driving power source of the hybrid vehicle and the generator is driven by the engine to supply power to at least one of the battery and the driving motor. A control apparatus for a hybrid vehicle, characterized by executing power generation control.

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