JP2020142633A - Control device and hybrid vehicle - Google Patents

Abstract

To provide a control device and a hybrid vehicle capable of generating assistive torque, required when a vehicle starts moving, in accordance with a state of the vehicle.SOLUTION: A control device comprises: an assist electric energy derivation section 32 which derives required assisting electric energy (first electric energy) required to enable a motor generator 11 to generate torque assisting an engine 10 when a hybrid vehicle 1 starts moving on the basis of information on a grade of a ground surface where the hybrid vehicle 1 is stopped; a target SOC determination section 34 which determines a target charging rate of a battery 16 on the basis of a state of charge (SOC) of a battery and the required assisting electric energy; and a motor generator control section 35 which causes the motor generator 11 to generate electricity necessary to charge the battery 16 to the target SOC while the hybrid vehicle 1 is stopped.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a hybrid vehicle control device and a hybrid vehicle that assist the torque of a prime mover required at the time of starting or the like by a motor.

Hybrid electric vehicles (HEVs) equipped with a motor generator and an internal combustion engine as power sources have become widespread. Such an HEV includes a parallel system in which a motor generator assists power in an inefficient rotation region (low rotation region such as when starting or sudden acceleration) in an internal combustion engine such as an engine.

In such a parallel type HEV, the power generated by the internal combustion engine may be input to the motor generator, and the motor generator may be operated as a generator to charge the battery. For example, Patent Document 1 discloses a technique for charging a battery by operating a generator by driving an engine while the vehicle is stopped when the remaining battery capacity is less than a preset capacity when the vehicle is stopped. ..

Japanese Unexamined Patent Publication No. 2012-116271

In the technique disclosed in Patent Document 1, when the remaining capacity of the battery becomes less than a predetermined determination value, the battery is charged while the vehicle is stopped, and when the battery is charged to the determination value or more, the power input to the battery is cut off for charging. To stop. That is, the maximum value of the remaining capacity of the battery charged while the vehicle is stopped is constant regardless of the state of the vehicle.

When the HEV starts from a stopped state, the electric power charged in the battery drives the motor generator to assist the torque required at the time of starting. For example, when starting uphill, more driving force is required than when starting on flat ground, so the torque generated by the motor generator for assist is increased. This improves the startability of the vehicle. When starting on such an uphill, the motor generator requires a larger amount of power than when starting on flat ground, so a large load is applied to the battery and the voltage drops, and assist when the battery charge is small. The required torque may not be obtained.

In view of such circumstances, it is an object of the present disclosure to provide a control device and a hybrid vehicle capable of assisting the torque required at the time of starting according to the state of the vehicle.

The control device according to one aspect of the present disclosure includes an internal combustion engine, a motor generator, and a battery, and the battery can be charged by causing the motor generator to generate electricity by the power generated by the internal combustion engine while the vehicle is stopped. In order to generate a torque for assisting the internal combustion engine in the motor generator when the hybrid vehicle starts, based on information on the slope of the ground on which the hybrid vehicle is stopped. The assist power amount derivation unit that derives the first electric energy required for the battery, the target charge rate determination unit that determines the target charge rate of the battery based on the current charge rate of the battery and the first electric energy, and the above. It has a motor generator control unit that generates electricity so as to charge the battery to the target charge rate while the hybrid vehicle is stopped.

The hybrid vehicle according to one aspect of the present disclosure has the above control device.

According to the present disclosure, it is possible to assist the torque required at the time of starting according to the state of the vehicle.

The figure which shows the configuration example of the hybrid vehicle in this embodiment The figure which shows an example of the functional block about idle charge in a control device. Flow chart for explaining the process related to idle charging by the control device Diagram exemplifying the performance curve of the hybrid system used to create the required assist power map Schematic diagram showing an example of the results of a hybrid vehicle start acceleration simulation at a given gradient and vehicle weight

Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. However, more detailed explanations than necessary, such as detailed explanations of already well-known matters and duplicate explanations for substantially the same configuration, may be omitted.

FIG. 1 is a diagram showing a configuration example of the hybrid vehicle 1 according to the present embodiment. The dotted line in FIG. 1 is a line schematically showing the flow of an electric signal.

The hybrid vehicle 1 shown in FIG. 1 is a vehicle including an ordinary passenger car, a bus, a truck, and the like. The hybrid vehicle 1 has a hybrid system 20 including an engine 10 and a motor generator 11 that are complexly controlled according to the driving state of the vehicle.

The engine 10 rotates and drives the crankshaft 12 by the thermal energy obtained by burning the fuel. A diesel engine or a gasoline engine is used for the engine 10. The rotational power of the engine 10 is transmitted to drive wheels (not shown) via a clutch 13 (for example, a wet multi-plate clutch or the like) connected to one end of the crankshaft 12 and a transmission 14. As a result, the hybrid vehicle 1 runs.

A battery 16 is connected to the motor generator 11 via an inverter 15. The inverter 15 mutually converts a direct current and an alternating current. The battery 16 is a rechargeable secondary battery, and is composed of, for example, a lithium ion battery, a nickel hydrogen battery, or the like.

Although the description is omitted in the present embodiment, as another configuration using the electric power of the battery 16, a DC / DC converter for supplying electric power to the low-voltage battery, a vehicle electrical component, or the like is connected to the battery 16. May be good. Examples of vehicle electrical components include electric air conditioners, electric hydraulic pumps, and the like.

An endless belt-shaped member 17 is hung around the output shaft of the motor generator 11 between the other end of the crankshaft 12 of the engine 10 (the end opposite to the transmission 14 side). Power is transmitted between the motor generator 11 and the engine 10 by the belt-shaped member 17.

The control device 30 controls the operation of the hybrid system 20 including the engine 10 and the motor generator 11. Although not shown, the control device 30 includes a CPU that performs various processes, an internal storage device that can read and write programs and processing results used for performing the various processes, and various interfaces.

The configuration of the hybrid vehicle 1 according to the present embodiment has been described above. The control of the hybrid system 20 by the control device 30 will be described below.

For example, when the hybrid vehicle 1 starts or accelerates, the control device 30 drives the motor generator 11 and controls the engine 10 to assist the engine 10 by using the driving force generated by the motor generator 11. As a result, the engine 10 which cannot obtain a large torque at low rotation due to its characteristics can be assisted by using the driving force of the motor generator 11, so that the torque required at the time of starting or accelerating is secured and is quick. It is possible to start and accelerate. In the present embodiment, the torque assisted by the motor generator 11 at the time of starting is referred to as an assist torque.

Further, the control device 30 controls to charge the battery 16 by converting the surplus kinetic energy into electric power by performing regenerative power generation by the motor generator 11 during inertial running or braking of the hybrid vehicle 1. As a result, fuel efficiency (electricity cost) can be improved.

Further, when the hybrid vehicle 1 is stopped, the control device 30 drives the engine 10 to rotate the motor generator 11 based on the charge rate (SOC: State of Charge) of the battery 16 to rotate the battery. 13 are charged. In the following description, driving the engine 10 to charge the vehicle when the vehicle is stopped will be referred to as idle charging.

Hereinafter, the control related to idle charging by the control device 30 will be described in detail. FIG. 2 is a diagram showing an example of a functional block related to idle charging in the control device 30. As shown in FIG. 2, the control device 30 includes a chargeability determination unit 31, an assist electric energy derivation unit 32, a usable electric energy derivation unit 33, a target SOC (State of Charge) determination unit 34, and a motor generator control unit 35. Has.

Further, FIG. 3 is a flowchart for explaining a process related to idle charging by the control device 30.

In step S1, the chargeability determination unit 31 determines whether or not idle charging is possible based on the vehicle speed information of the hybrid vehicle 1 obtained from a vehicle speed sensor or the like (not shown). For example, the chargeability determination unit 31 determines that idle charging is possible when the vehicle speed is 0 (hybrid vehicle 1 is stopped), and when it is not (hybrid vehicle 1 is running). Determines that idle charging is not possible. If it is determined that idle charging is possible (step S1: YES), the process proceeds to step S2, and if not (step S1: NO), the process repeats step S1.

In step S2, the assist electric energy deriving unit 32 derives the electric energy for the motor generator 11 to perform the necessary assist (hereinafter, the required assist electric energy) based on the gradient information and the vehicle weight information. The gradient information is information regarding the gradient of the ground on which the hybrid vehicle 1 is currently stopped, which is obtained from a gradient sensor or the like (not shown). Further, the vehicle weight information is information on the current vehicle weight of the hybrid vehicle 1 obtained from a vehicle weight sensor or the like (not shown). In addition, in this embodiment, the present time means the time when processing is performed.

The required assist power amount means the amount of power required by the motor generator 11 to generate the assist torque described above. The assist electric energy derivation unit 32 determines the required assist electric energy based on the gradient information and the vehicle weight information by using the required assist electric energy map created in advance. The required assist electric energy map is a map (for example, a table) showing the relationship between the gradient, the vehicle weight, and the required assist electric energy, and is stored in advance in a memory or the like (not shown).

Examples of the method for creating the required assist electric energy map include the following methods. First, for example, based on the performance curve of the hybrid system 20, the start acceleration simulation of the hybrid vehicle 1 is performed for each gradient and for each vehicle weight, and the total amount of required assist torque is derived. Then, the required assist power amount for each gradient and each vehicle weight is derived based on the total amount of the required assist torque. By tabulating the required assist electric energy derived in this way for each gradient and for each vehicle weight, a required assist electric energy map is created. The required assist electric energy map may be created by a simulator or the like (not shown).

FIG. 4A is a diagram illustrating a performance curve of the hybrid system 20 used for creating a required assist electric energy map. The horizontal axis of FIG. 4A corresponds to the engine speed, and the vertical axis corresponds to the torque. FIG. 4A shows a torque curve (maximum torque for each rotation speed) 41 of the hybrid system 20 and a region 42 showing the relationship between the engine rotation speed and the assist torque by the motor generator 11. As shown in region 42 of FIG. 4A, in the hybrid system 20, the magnitude of the assist torque by the motor generator 11 is determined by the engine speed. In the example shown in FIG. 4A, when the predetermined engine speed R1 is exceeded, the assist torque by the motor generator 11 becomes 0. The performance curve of the hybrid system 20 shown in FIG. 4A is an example, and the present invention is not limited thereto.

Based on the performance curve shown in FIG. 4A, changes in the vehicle speed of the hybrid vehicle 1 and changes in the required assist torque at a predetermined gradient and vehicle weight are simulated. FIG. 4B is a schematic diagram showing an example of the result of the start acceleration simulation of the hybrid vehicle 1 at a predetermined gradient and vehicle weight. FIG. 4B schematically shows a curve 43 showing a change in the vehicle speed of the hybrid vehicle 1 obtained as a result of the simulation, and lines 44, 45, 46 showing a change in the required assist torque. In the example of the simulation result shown in FIG. 4B, it is assumed that the predetermined gradient continues even after the hybrid vehicle 1 starts. The horizontal axis of FIG. 4B corresponds to time, and the vertical axis corresponds to vehicle speed or torque.

In FIG. 4B, it is simulated that the hybrid vehicle 1 starts from a vehicle speed of 0, accelerates, and is assisted by the motor generator 11 until it reaches a constant speed. Lines 44 to 46 indicate assist torques in different gears, and line 44 corresponds to 1st speed, line 45 corresponds to 2nd speed, and line 45 corresponds to 3rd speed. The assist by the motor generator 11 is started at the rising start time (assist start time in the first speed) of the line 44, and the required assist torque gradually decreases as the engine speed increases (see FIG. 4A). Then, when the engine speed exceeds the speed R1 shown in FIG. 4A, the required assist torque once becomes 0 (the region between the falling edge of the line 44 and the rising edge of the line 45). In this state, when the engine speed is lowered by shifting up to the second speed and becomes smaller than the speed R1, the assist by the motor generator 11 is started again as shown by the line 45. Further, as the engine speed increases, the required assist torque becomes 0 again (the region between the falling edge of the line 45 and the rising edge of the line 46). By shifting up to the third speed in this state, the engine speed decreases, and as shown by line 46, the assist by the motor generator 11 is started again.

By integrating the change in the required assist torque shown in FIG. 4B over time, the total amount of the required assist torque (the total area of the shaded areas in FIG. 4B) can be obtained. The required assist power amount corresponds to the total amount of the required assist torque, and if the total amount of the required assist torque is known, it can be derived on a simulation. In this way, the required assist power amount at a predetermined gradient and vehicle weight is derived. The required assist electric energy map is created by performing the above-mentioned simulation with various changes in the gradient and the vehicle weight.

Returning to the description of FIG. In step S3, the usable electric energy derivation unit 33 currently uses the electric energy (usable electric energy) that can be used for assist by the motor generator 11 based on the SOC information of the battery 16 and the other configuration electric energy information. Is derived. The SOC information is information on the charge rate of the battery 16 at the present time. Further, the other configuration power consumption information is information on the current power consumption of other devices connected to the battery 16 and using the power of the battery 16. The SOC information and other configuration power consumption information are information acquired from, for example, the battery 16. The usable electric energy derivation unit 33 derives the usable electric energy that can be used at the present time by, for example, subtracting the electric energy used by another configuration from the SOC at the present time.

In step S4, the target SOC determination unit 34 determines the target SOC (SOC _object ) based on the current SOC (SOC _present ), the required assist power amount ( _System ), and the available power amount ( _Qoverable ). To do. The target SOC is a target value of the SOC of the battery 16 charged by idle charging.

The target SOC determination unit 34 determines the target SOC using, for example, the following mathematical formula (1).
_{SOC object = SOC present + (Q} assist -Q available) / Q battery (1)

The Q _battery is the amount of power corresponding to the usable range of the total capacity of the battery 16 (hereinafter, referred to as the total amount of battery power).

A specific example will be given. For example, (required assist power amount / total battery power amount) is 20% of SOC 100%, (usable power amount / total battery power amount) is 15%, and the current SOC is 50%. Then, the target SOC is 50% + (20% -15%) = 55%. The method for determining the target SOC by the target SOC determination unit 34 described above is an example, and the present invention is not limited thereto.

In step S5, the motor generator control unit 35 transmits a motor generator control signal for controlling the motor generator 11 so as to charge the battery 16 to the target SOC. In the idle charging process, the engine 10 maintains rotation at a predetermined rotation speed, and the motor generator 11 can be charged by the rotation of this engine. The motor generator control unit 35 causes the motor generator 11 to generate power until the SOC of the battery 16 reaches the target SOC, and stops the power generation of the motor generator 11 when the target SOC is reached.

By the process described above, the amount of assist power required for starting is derived based on the slope of the ground on which the hybrid vehicle 1 is stopped, and the battery 16 is charged to the target SOC accordingly. Therefore, even when the vehicle is stopped at a place where a large assist torque is required, such as an uphill, a sufficient amount of assist power can be supplied to the motor generator 11 to output a large assist torque.

<Action / effect>
As described above, the control device according to the embodiment of the present disclosure has an engine (internal engine) 10, a motor generator 11, and a battery 16, and the motor generator 11 is driven by the power generated by the engine 10 while the vehicle is stopped. The control device 30 of the hybrid vehicle 1 capable of charging the battery 16 by generating electric power, and when the hybrid vehicle 1 starts based on information on the slope of the ground on which the hybrid vehicle 1 is stopped. The assist power amount derivation unit 32 that derives the required assist power amount (first power amount) required to generate the torque for assisting the engine 10 in the motor generator 11, the current charge rate (SOC) of the battery, and the required assist power. A target SOC determination unit 34 that determines a target charge rate of the battery 16 based on the amount, and a motor generator control unit 35 that generates a motor generator 11 so as to charge the battery 16 to the target charge rate while the hybrid vehicle 1 is stopped. And have.

With such a configuration, the battery 16 can be charged to the SOC that can sufficiently supply the assist power amount required when the hybrid vehicle 1 starts according to the slope of the ground on which the hybrid vehicle 1 is stopped. As a result, since the target SOC is set large in a situation where a large amount of assist power is required such as uphill, it is possible to avoid a situation in which the required amount of assist power is not supplied because the SOC is insufficient. Therefore, the torque according to the state of the hybrid vehicle 1 is always assisted by the motor generator 11, and smooth starting and acceleration are possible even when the vehicle is stopped at any slope.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and can be appropriately modified and implemented without departing from the spirit of the present disclosure.

In the above-described embodiment, an example in which the driving force of the engine 10 is assisted by driving the motor generator 11 with the electric power of the battery 16 has been described, but the present disclosure is not limited to this. For example, an electric supercharger (electric turbo or electric supercharger) that supercharges the engine with the electric power of the battery may be used to assist the driving force of the engine. Further, it may be configured to have both a motor generator and an electric supercharger. Even when assisting with an electric supercharger, the target SOC is derived by deriving the amount of power required for assisting with the electric supercharger using a map or the like created in advance, as in the embodiment described above. It may be configured to determine.

In the above embodiment, the case where the hybrid vehicle 1 continues to stop until the target SOC has been described, but when the driver performs the start operation of the hybrid vehicle 1 while the hybrid vehicle 1 is not charged to the target SOC, the hybrid vehicle 1 is charged. It is sufficient to interrupt and start appropriately. If the vehicle starts uphill and is not charged to the target SOC, the required assist power amount may be insufficient. Therefore, when starting on an uphill and when the vehicle is not charged to the target SOC, the assist amount by the motor generator 11 may be smaller than that when the vehicle is charged to the target SOC.

In the above-described embodiment, an example of adopting a belt alternator starter (BAS: Belt Alternator Starter) type hybrid system 20 in which the engine 10 and the motor generator 11 are connected by a belt-shaped member 17 has been described. However, the present disclosure is not limited to this, and other hybrid systems may be adopted as long as the motor is a hybrid system that assists the driving force of the engine.

The present disclosure is useful for hybrid vehicles in which the motor assists the driving force of the engine.

1 Hybrid vehicle 10 Engine 11 Motor generator 12 Crank shaft 13 Clutch 14 Transmission 15 Inverter 16 Battery 17 Belt-shaped member 20 Hybrid system 30 Control device 31 Chargeability judgment unit 32 Assist electric energy extraction unit 33 Usable electric energy extraction unit 34 Target SOC Decision unit 35 Motor generator control unit

Claims (4)

A control device for a hybrid vehicle including an internal combustion engine, a motor generator, and a battery, and capable of charging the battery by causing the motor generator to generate electricity by the power generated by the internal combustion engine while the vehicle is stopped.
Based on the information about the slope of the ground on which the hybrid vehicle is stopped, the first electric energy required to generate the torque for assisting the internal combustion engine when the hybrid vehicle starts is derived from the motor generator. Assist electric energy derivation unit and
A target charge rate determining unit that determines a target charge rate of the battery based on the current charge rate of the battery and the first electric energy.
A motor generator control unit that generates electricity so as to charge the battery to the target charge rate while the hybrid vehicle is stopped.
Has a control device. The assist electric energy deriving unit derives the assist electric energy by using an assist electric energy map showing the relationship between the gradient and the weight of the hybrid vehicle and the assist electric energy.
The control device according to claim 1. The hybrid vehicle further includes an electric supercharger that supercharges the internal combustion engine using the electric power of the battery.
Based on the information, the assist electric energy deriving unit is required to generate a torque for assisting the internal combustion engine in the motor generator and / or the electric supercharger when the hybrid vehicle starts. Derived the amount of power,
The target charge rate determining unit determines the target charge rate of the battery based on the current charge rate of the battery and the second electric energy.
The control device according to claim 1 or 2. A hybrid vehicle having the control device according to any one of claims 1 to 3.

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