JP2010167964A - Control device and control method for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase cruising range by extending EV travelling range to improving fuel economy while giving top priority to fuel consumption when the remaining fuel is at a low remaining amount range showing almost running out of gas and when the cruising range is emphasized. <P>SOLUTION: The driving mode of a power system is controlled. In the power system, both or either an engine or a motor selectively operates in a mode according to a set condition. A power system operation mode change control section 120 sets a different condition from a case when the remaining amount of the fuel is not less than a predetermined value when the remaining amount of the fuel according to the remaining amount of fuel information acquired by a fuel remaining amount information acquiring section 110 is in a low remaining amount range where the remaining amount of the fuel is less than a predetermined value, in this control. That is, a control mode is changed to change the condition so that the operation opportunity for the engine is relatively reduced when the remaining amount of the fuel is in the low level remaining amount range less than the predetermined value, than when the remaining amount of the fuel is not less than the predetermined value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  According to the present invention, an internal combustion engine (hereinafter referred to as an engine) and / or an electric motor (hereinafter referred to as a motor) as a power source capable of driving a drive wheel is selectively used in a mode according to a set condition. The present invention relates to a control device for a hybrid vehicle having an operating power system.

The hybrid vehicle has a mode (hereinafter, EV traveling) in which the engine is stopped and the vehicle travels only with the motor. When the remaining amount of engine fuel is low, EV traveling can be performed by the electric energy of the battery. For this reason, even when the engine fuel runs out, the vehicle can travel a certain distance, and the cruising distance can be increased (see, for example, Patent Document 1).
In the technique described in Patent Document 1, in order to extend the EV travel distance even when the engine fuel level is low and the engine runs short, if the fuel level falls below a certain threshold value, Control is performed so as to increase the control value of the remaining battery level (SOC). That is, it is a technical proposal to increase the EV travel distance by securing a larger amount of remaining battery power when the gas runs out.

JP 2004-320946 A

In this proposal, in order to increase the level of charge (SOC) of the battery before gas shortage, a charge / discharge command centered on the battery SOC higher than that during normal control is given to the battery charging circuit. Therefore, a battery power request is generated at a frequency higher than that during normal control or for a longer time.
In order to satisfy the charging request as described above, one or both of the following two measures are taken.
In one measure, the engine is controlled to operate more than necessary to drive the vehicle in order to satisfy the charging request for the battery, and the surplus energy is used for charging the battery. That is, the engine consumes traveling fuel mounted on the vehicle and generates electric power for charging the battery.

  In the other measure, the motor functions as a generator by the deceleration energy of the vehicle, and in the process of charging the battery with the electric energy generated by the power generation (hereinafter referred to as regeneration), the motor and inverter are charged. Control the electrical equipment. That is, originally, a part of the regenerative power that can be used for the next motor running or acceleration assist is used for charging to increase the SOC of the battery. For this reason, the amount of power to be used for charging must be obtained by consuming the fuel for running and operating the engine.

Therefore, even when any of the above measures is taken, it is considered that when the battery is charged to raise the battery SOC, more fuel for traveling is consumed than during normal control.
That is, the EV travel distance after the fuel runs out can be extended, but after the fuel becomes less than the predetermined value, the electric power stored in the battery is increased while consuming more fuel than during normal travel. As a result, there is a problem that the travel distance until the fuel runs out becomes short.
The present invention has been made in view of the above situation, and it is possible to increase the cruising distance comprehensively by performing traveling drive control appropriately interwoven with EV traveling under conditions where fuel is limited. An object of the present invention is to realize a control device and a control method for a hybrid vehicle.

In order to solve the above problems, the charging control device for a hybrid vehicle according to the present invention comprises the following means.
That is, the control apparatus for a hybrid vehicle according to the present invention includes a power system in which either or both of an internal combustion engine and an electric motor as a power source capable of driving drive wheels are selectively operated in a mode according to a set condition. The drive mode is controlled.

A fuel remaining amount information acquisition unit is provided, and information indicating the remaining amount of fuel of the internal combustion engine is acquired by the fuel remaining amount information acquisition unit.
In addition, a power system operation mode change control unit is provided, and a low level remaining amount region in which the remaining amount of fuel by the remaining fuel amount information acquisition unit acquired by the fuel system operation mode change control unit is less than a predetermined value If it is, the condition different from the case where the remaining amount of the fuel is not less than a predetermined value is set.
In other words, when the remaining amount of fuel is in the low level remaining amount range below the predetermined value, the operation opportunity of the internal combustion engine is relatively decreased as compared with the case where the remaining amount of fuel is greater than or equal to the predetermined value. Change the setting of the condition.

  The opportunity to operate the internal combustion engine (engine) can be adjusted appropriately, and the cruising range of the hybrid vehicle can be increased.

It is a functional block diagram showing the control apparatus of the hybrid vehicle as one embodiment of this invention. It is a flowchart showing the whole operation | movement of the hybrid vehicle control apparatus of FIG. It is a figure for demonstrating the operating point of EV driving | running | working by the hybrid vehicle control apparatus of FIG. It is a figure for demonstrating the fuel consumption characteristic by the control apparatus of the hybrid vehicle of FIG. FIG. 2 is a diagram for explaining an EV region related to the operation of the hybrid vehicle control device of FIG. 1. It is a figure for demonstrating the example of the change of the charging / discharging map by the control apparatus of the hybrid vehicle of FIG.

Hereinafter, the present invention will be clarified by describing embodiments of the present invention in detail with reference to the drawings.
(Configuration of control device for hybrid vehicle)
FIG. 1 is a functional block diagram showing a control apparatus for a hybrid vehicle as one embodiment of the present invention.

The hybrid vehicle control device 100 is a hybrid vehicle control device that includes a power system in which either or either of the engine and the motor is selectively operated in accordance with a set condition.
A fuel remaining amount information acquisition unit 110 that receives information indicating the remaining amount of fuel of the engine in response to fuel remaining amount detection data that is a detection output of the fuel gauge, and setting of conditions for selectively operating the engine and the motor And a power system operation mode change control unit 120 that changes the power.

The power system operation mode change control unit 120, when the remaining amount of fuel based on the remaining fuel amount information acquired by the remaining fuel amount information acquiring unit 110 is in a low level remaining amount region below a predetermined value, A measure is taken in which the engine operation opportunity is relatively lower than in the case where the value is equal to or greater than the predetermined value.
That is, when the remaining amount of fuel according to the remaining fuel amount information acquired by the remaining fuel amount information acquisition unit 110 is in a low level remaining amount region that is less than a predetermined value, the remaining amount of fuel is greater than or equal to a predetermined value. Also, the setting of the condition is changed so that the engine operation opportunity is relatively lowered.

When the remaining amount of fuel is in the above-described low level remaining amount region, the power system operation mode change control unit 120 defines the relationship between the remaining amount value of the battery that is the power source of the motor and the charging / discharging power. The setting of the condition is changed by switching the map to one corresponding to the low level remaining area.
Therefore, the power system operation mode change control unit 120 switches and refers to different charge / discharge maps depending on the case, and performs this switching based on the fuel remaining amount information acquired by the fuel remaining amount information acquiring unit 110.

On the other hand, the power system operation mode change control unit 120 refers to, for example, a charge / discharge map prepared in a ROM or the like that defines the relationship between the remaining battery level value and the charge / discharge power at a required timing. Either or both of the engine and the motor are selectively operated.
In other words, the charge / discharge map prescribes conditions for selectively operating either or both of the engine and the motor, the first charge / discharge map for normal driving, and the remaining amount of fuel is low. There is a second charge / discharge map applied in a specific case. In the present embodiment, the power system operation mode change control unit 120 selectively operates both or one of the engine and the motor by switching and selectively applying these two types of charge / discharge maps. To change.

The engine start and stop control is performed by issuing an engine stop command E1 and an engine start command E2 from the power system operation mode change control unit 120.
In general, in a hybrid vehicle having an EV travel mode, in order to determine the EV travel range, fuel consumption, power performance, battery life, and the like are all considered. For example, if the power for determining start / stop of the engine is low, the region in which EV traveling is possible becomes narrow, and the fuel efficiency effect by adopting the EV traveling mode in the low load region cannot be maximized. However, if the power for determining start / stop of the engine is high, the SOC of the battery rises and falls sharply, and depending on the running state, there arises a problem that drive power for assisting by the motor cannot be secured when re-acceleration is requested. In addition, the amount of charge and discharge to the battery increases, which places a burden on electrical equipment such as an inverter.

In the embodiment of the present invention, when the remaining amount of fuel is in the low level remaining amount range, such as before the so-called gas shortage, and when the driving range is high, the fuel efficiency is given the highest priority. Therefore, the EV travel range can be expanded to improve fuel efficiency and extend the cruising distance.
That is, when the remaining amount of fuel is less than the predetermined value, the driving force of the engine or the engine and the motor between the motor and the motor is compared with the driving state from the motor alone, compared to the case where the remaining amount of fuel is greater than the predetermined value. The above-mentioned conditions are changed so that it is difficult to shift to the running state by the driving force. Due to such a change in the conditions, when the remaining amount of fuel is small, traveling by only the driving force of the motor increases. Thereby, the increase in fuel consumption can be suppressed and the cruising range can be extended.

If driving by only the driving force of the motor increases, the battery will be burdened and its deterioration will be promoted, but since this control mode is entered only when the remaining amount of fuel is less than the predetermined value, It is possible to suppress the deterioration of the battery as compared with the case where the traveling by only the driving force of the motor is increased.
On the other hand, the power system operation mode change control unit 120 receives various information related to the battery from each corresponding sensor. That is, each information of battery remaining amount information (SOC) indicating the remaining amount of the battery, charging / discharging power information indicating the charging / discharging power, and battery usage state information indicating the usage state is received and acquired.

In the embodiment of the present invention, a map that specifies the required amount of charge and discharge to the battery using the SOC value of the battery as a parameter is switched and applied according to the remaining amount of fuel. That is, when the remaining amount of fuel is in a low-level remaining amount region close to a so-called gas shortage, the control condition is applied to which a map is applied so that the opportunity to operate the engine is smaller than in a normal case.
Only when the remaining amount of fuel is in a low-level remaining amount region close to the so-called out of gas, by entering the control mode in which the map applied to the control is switched as described above, the EV traveling region is expanded. A decrease in the SOC of the battery due to an increase in the battery usage frequency can be suppressed. That is, the SOC level of the battery can be kept flat before and after entering the control mode. Therefore, concerns such as insufficient driving force due to a decrease in SOC can be solved.

On the other hand, the above-described battery usage status information is not necessarily acquired from the sensor at one time, but is acquired based on the transition of usage status over a certain period of time. The power system operation mode change control unit 120 switches the charge / discharge map to be applied based on such battery usage information.
That is, based on the battery usage status information such as the charge / discharge amount of the battery while the vehicle is traveling, the EV travel range is expanded so as to adapt to the status. Thereby, the excessive charge / discharge to the battery can be suppressed, and the concern about the influence on the battery life due to the expansion of the EV travel range can be eliminated.

That is, when the battery use opportunity is relatively low, the fuel remaining amount threshold value for determining the low level remaining amount region is raised so that the control mode for expanding the EV traveling range is set. As a result, the EV travel range can be expanded from an earlier stage, the fuel efficiency can be improved, and the cruising distance can be extended.
On the other hand, when the battery is used relatively frequently, the fuel remaining amount threshold value for determining the low level remaining amount region is lowered so that the control mode is set to suppress the EV traveling range. Thereby, since the further increase in the use load to the battery due to the EV travel range expansion can be suppressed, the concern that affects the life of the battery can be eliminated.

As a result, when the remaining amount of fuel is in the low level remaining amount region, such as before the so-called gas shortage, both the requirements for the expansion of the cruising distance and the prevention of battery deterioration can be satisfied.
On the other hand, the present embodiment includes a traveling state estimation unit 130 that estimates the traveling state of the hybrid vehicle. The traveling state estimation unit 130 receives navigation information including GPS information and road traffic information from the navigation system, vehicle traveling pattern information generated by the controller of the hybrid vehicle, and the like, and estimates a traveling state based on these.

The traveling state estimation unit 130 supplies traveling state estimation information representing the traveling state obtained by estimation as described above to the power system operation mode change control unit 120.
The power system operation mode change control unit 120 changes the setting of conditions for selectively operating the engine and the motor based on the traveling state estimation information.
The improvement in fuel efficiency by changing the conditions that expands the EV driving range is significant during low-load driving with low engine work. You may take the aspect of not doing. That is, in a driving state where a fuel efficiency effect can be expected particularly on a general road or an urban area, the EV driving range can be expanded to an optimum EV driving range with a remarkable fuel efficiency effect corresponding to the driving load. As a result, a more reliable fuel efficiency improvement effect can be exhibited and the cruising distance can be extended.

(Overall operation of hybrid vehicle control system)
FIG. 2 is a flowchart showing the operation of the entire hybrid vehicle control device of FIG. 1 (including a controller not shown in FIG. 1). The overall operation of the hybrid vehicle control apparatus according to the embodiment of the present invention will be described below with reference to this flowchart.
In step S201, the accelerator opening by the driver is read.
In step S202, the brake depression amount by the driver is read.
In step S203, the speed of the vehicle body is read by the traveling speed detection means installed in the vehicle.

In step S204, the acceleration force (driving force) required by the driver for the vehicle is the accelerator opening degree indicating the driver's acceleration request read in step S201, or the brake depression amount indicating the deceleration request read in step S202, and step S203. Using the vehicle speed read in step 1, the power required for driving is calculated by obtaining from the map with these as axes.
In step S205, the remaining fuel amount F mounted on the vehicle is detected by the remaining fuel amount information acquiring unit 110.

In step S206, it is determined whether or not the remaining amount of fuel detected in step S205 is less than the threshold value Fth (step S206: Yes). If not (step S206: No), step S207 is performed. Migrate to
In step S209, the remaining fuel consumption warning signal E3 is issued, and the warning lamp is turned on using the fuel warning lamp lighting means based on the signal E3, thereby informing the driver that the gas is almost exhausted.
In step S2010, an SOC indicating the remaining amount of battery energy and a second charge / discharge map applied in a specific case where the remaining amount of fuel is at a low level are read from the map centered on the charge / discharge power.

In step S211, the battery life is estimated by reading the battery discharge integrated amount (Ah).
In step S212, the running state of the vehicle is estimated using vehicle information or navigation information.
In step S2013, the power to start the engine and the power to stop before the gas shortage are set based on the battery discharge integrated amount (Ah) and the running state estimation information, and the process proceeds to step S214.

In step S207, the first charge / discharge map for normal travel driving is read from the map with the SOC indicating the remaining energy of the battery and the charge / discharge power as an axis.
In step S208, data for normal driving of the power for starting and stopping the engine is read, and the process proceeds to S214.
In step S214, the SOC indicating the remaining energy of the battery is read.

In step S215, the charging / discharging corresponding to the SOC is performed using the normal charge driving data read in step S208 or the second charge / discharge map applied in a specific case where the remaining amount of fuel read in step S210 is low. Calculate the discharge power.
In step S216, the required power finally required for the engine is calculated by taking the sum of drive power and charge / discharge power.
In step S217, it is determined whether the engine is running and the required power is less than the stop power set in step S208 or step S213. If not (step S217: No), the process proceeds to step S219. If it is less (step S217: Yes), the process proceeds to step S218, the engine is stopped, and the process proceeds to step S219.

  In step S219, it is determined whether or not the engine is stopped and the required power exceeds the starting power set in step S208 or step S213. If not (step S219: No), the process proceeds to return. On the other hand, if it exceeds, it will transfer to step S220, will start an engine, and will transfer to a return.

  FIG. 3 is a diagram for explaining an operating point of EV traveling by the hybrid vehicle control device of FIG. 1. When the start / stop power is changed and the EV range is expanded, the operation at the engine low load operating point is not performed. As indicated by the engine average fuel consumption rate contour shown in the figure, the engine low load operating point is inefficient. By avoiding such driving, if the increase in engine work is suppressed, overall efficiency can be increased and fuel efficiency is improved.

FIG. 4 is a diagram for explaining fuel consumption characteristics by the hybrid vehicle control device of FIG. 1.
FIG. 4A shows a change example of the average fuel consumption rate in the embodiment of the present invention, and FIG. 4B shows a change example of the engine work. The average fuel consumption rate in FIG. 4 (a) is an index representing the amount of fuel consumed to obtain unit output energy, and the smaller the value, the more efficient the output is obtained with less fuel. Further, the engine work in FIG. 4B represents the total amount of work performed by the engine for traveling, and generally the fuel consumption is determined by the product of the average fuel consumption rate and the engine work. By expanding the EV region, low-load operation with poor engine efficiency is not performed, and the average fuel consumption rate is improved as much as shown in the figure. However, since the expansion of the EV region increases the engine work by increasing losses such as charging and discharging, the engine work increases as shown in the figure. Due to such a background, the efficiency of the entire vehicle increases when engine work is suppressed, such as in a low-load running state, so that fuel efficiency is improved.

  FIG. 5 is a diagram for explaining an EV region related to the operation of the hybrid vehicle control device of FIG. 1. FIG. 5 shows an example of the engine output request value and the EV region. When the engine output request value exceeds the starting power, EV traveling is stopped and the engine is started. Further, when the engine output request value falls below the stop power, the engine is stopped and the EV traveling is started. It can be seen from the figure that the EV traveling area is expanded by increasing the starting power and the stopping power as compared with the case of normal traveling driving. At that time, the engine will not operate at a low-efficiency operating point with a low load, and if the increase in engine work is suppressed, the overall efficiency is improved and the fuel efficiency is improved.

  FIG. 6 is a diagram for explaining an example of change of the charge / discharge map by the hybrid vehicle control device of FIG. 1. An example in which the setting of the charge and discharge request map is changed when the EV travel area is expanded as compared with the case of the normal travel drive is shown. As shown in the figure, even if the EV travel frequency increases and the power consumption increases by increasing the required output on the charging side, it is possible to prevent the central value of the battery SOC from rapidly decreasing.

(Effect in the embodiment of the present invention)
The effects of the embodiment of the present invention described above are listed below in relation to the configuration.
(1) Either or both of the engine and the motor control the driving mode for the power system that selectively operates in a mode according to the set condition. In this control, when the remaining amount of fuel based on the remaining fuel amount information acquired by the remaining fuel amount information acquiring unit 110 is in a low level remaining amount region below a predetermined value by the power system operation mode change control unit 120, Conditions different from the case where the remaining amount of fuel is a predetermined value or more are set. That is, when the remaining amount of fuel is in the low level remaining amount range below the predetermined value, the engine operation opportunity is relatively decreased as compared with the case where the remaining amount of fuel is equal to or greater than the predetermined value. Enter the control mode with the changed condition settings.

  For this reason, when the remaining amount of fuel is in a low level remaining amount range, such as before the so-called gas shortage, and the vehicle is in a traveling state where the demand for the cruising distance is high, the EV traveling is to be given the highest priority on fuel efficiency. The range can be expanded to improve fuel efficiency and extend the cruising range. Further, since such a control mode is entered only when the remaining amount of fuel is less than a predetermined value, it is possible to suppress the deterioration of the battery as compared with the case where the traveling by only the driving force of the motor is always increased.

(2) Particularly in the above (1), the power system operation mode change control unit 120, when the remaining amount of fuel is in the low level remaining amount region, the remaining amount value of the battery that is the power source of the motor and the charge / discharge power The above-mentioned condition setting is changed by switching the charge / discharge map that defines the relationship with the above to one corresponding to the low level remaining amount region.
Only when the remaining amount of fuel is in a low-level remaining amount region close to the so-called out of gas, by entering the control mode in which the map applied to the control is switched as described above, the EV traveling region is expanded. A decrease in the SOC of the battery due to an increase in the battery usage frequency can be suppressed. That is, the SOC level of the battery can be kept flat before and after entering the control mode. Therefore, concerns such as insufficient driving force due to a decrease in SOC can be solved.

(3) In (1) above, in particular, when the remaining amount of fuel is in the low level remaining amount region, the power system operation mode change control unit 120 is based on information representing the usage status of the battery that is the power source of the motor. To change the above condition settings.
For this reason, when the usage opportunity of the battery is relatively low, the fuel remaining amount threshold value for determining the low level remaining amount region is raised so that the control mode is set to expand the EV traveling range. Thereby, the EV travel range can be expanded from an earlier stage, fuel efficiency can be improved, and the cruising distance can be extended.

On the other hand, when the battery is used relatively frequently, the fuel remaining amount threshold value for determining the low level remaining amount region is lowered so that the control mode is set to suppress the EV traveling range. Thereby, since the further increase in the use load to the battery due to the expansion of the EV traveling range can be suppressed, the concern that affects the life of the battery can be eliminated.
As a result, when the remaining amount of fuel is in the low level remaining amount region, such as before the so-called gas shortage, both the requirements for the expansion of the cruising distance and the prevention of battery deterioration can be satisfied.

(4) Particularly in the above (1), the power system operation mode change control unit 120, when the remaining amount of fuel is in the low level remaining amount region, the estimation information on the traveling state of the hybrid vehicle (the traveling state estimating unit) The above condition setting is changed on the basis of 130 output).
For this reason, in the driving | running | working state which can anticipate especially a fuel-consumption effect on a general road, a city area, etc., the expansion of the optimal EV driving | running | working range where the fuel-consumption effect according to the driving | running | working load is remarkable can be aimed at by expanding an EV driving | running range. . As a result, a more reliable fuel efficiency improvement effect can be exhibited and the cruising distance can be extended.

(5) In the control method of the hybrid vehicle corresponding to the device of (1) above, there is a high demand for the cruising distance when the remaining amount of fuel is in a low level remaining amount region, such as before the so-called gas shortage. The cruising range can be extended when the vehicle is in a running state. That is, when the remaining amount of fuel is in the low level remaining amount region as described above, the EV traveling range can be expanded to improve the fuel efficiency so that the fuel efficiency is given the highest priority. Further, since such a control mode is entered only when the remaining amount of fuel is less than a predetermined value, it is possible to suppress the deterioration of the battery as compared with the case where the traveling by only the driving force of the motor is always increased.

DESCRIPTION OF SYMBOLS 100 ... Hybrid vehicle control apparatus 110 ... Fuel remaining amount information acquisition part 120 ... Power system operation mode change control part 130 ... Running condition estimation part

Claims (5)

A control apparatus for a hybrid vehicle having a power system that selectively operates in a mode according to a set condition, either or both of an internal combustion engine and an electric motor as a power source capable of driving a drive wheel,
A fuel remaining amount information acquisition unit for acquiring information representing the remaining amount of fuel of the internal combustion engine;
When the fuel remaining amount by the fuel remaining amount information acquired by the fuel remaining amount information acquiring unit is in a low level remaining amount region that is less than a predetermined value, the fuel remaining amount is higher than a predetermined value than A power system operation mode change control unit that changes the setting of the condition so that the operation opportunity of the internal combustion engine is relatively lowered;
A control apparatus for a hybrid vehicle, comprising:   When the remaining amount of fuel is in the low level remaining amount region, the power system operation mode change control unit regulates charging / discharging that defines a relationship between a remaining amount value of a battery that is a power source of the electric motor and charging / discharging power. 2. The control apparatus for a hybrid vehicle according to claim 1, wherein the setting of the condition is changed by switching a map corresponding to the low level remaining amount range.   The power system operation mode change control unit changes the setting of the condition based on information indicating a usage state of a battery that is a power source of the electric motor when the remaining amount of fuel is in the low level remaining amount region. The control apparatus for a hybrid vehicle according to claim 1.   The power system operation mode change control unit changes the setting of the condition based on estimation information related to a traveling state of the hybrid vehicle when the remaining amount of fuel is in the low level remaining amount region. The hybrid vehicle control device according to claim 1. A control method for a hybrid vehicle including a power system that selectively operates in a mode according to a set condition, either or both of an internal combustion engine and an electric motor,
When the remaining amount of fuel in the internal combustion engine is in a low level remaining amount region below a predetermined value, the operation opportunity of the internal combustion engine is relatively lower than in the case where the remaining amount of fuel is greater than or equal to a predetermined value. Thus, the control method for the hybrid vehicle is characterized by changing the setting of the condition.

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