JP2024098876A - Hybrid vehicle control device - Google Patents

Abstract

To provide a control device of a hybrid vehicle which control device can properly perform automatic stop and restart of an engine.SOLUTION: A hybrid vehicle includes: an engine; a motor connected to a crank shaft of the engine and driven by output torque of the engine to be capable of generating power; and a battery capable of supplying and receiving power to/from the motor. The hybrid vehicle performs automatic stop and restart of the engine. When performing the automatic stop, a control device of the hybrid vehicle, executes engine stop position control of applying braking torque to the crank shaft by regenerating the motor and stopping the crank shaft at a prescribed target stop position, and also acquires allowable charge power as the allowable power to charge the battery, and prohibits execution of the automatic stop when the allowable charge power is less than a prescribed reference power (step S4).SELECTED DRAWING: Figure 3

Description

This invention relates to a control device for a hybrid vehicle equipped with an engine (internal combustion engine) and a motor as a driving force source.

Patent Document 1 describes a control device for a hybrid vehicle that aims to control the crankshaft to stop within a predetermined target stopping range when the engine is stopped, regardless of the battery state. When stopping the engine, the control device for a hybrid vehicle described in Patent Document 1 controls the motor so that the stopping position of the crankshaft falls within the target stopping range if the remaining battery charge (SOC) is equal to or greater than a judgment threshold. When the battery SOC is less than the judgment threshold, the control device controls the engine valve mechanism so that the stopping position of the crankshaft falls within the target stopping range.

Patent Document 2 describes a vehicle control device that aims to improve the restart performance of the engine while maintaining the remaining battery charge appropriately. When the automatic engine stop condition is met and fuel supply is stopped, the vehicle control device described in Patent Document 2 activates the restart motor for a predetermined time to drive the engine crankshaft. After the predetermined time has elapsed, the restart motor is switched to either an active state, a neutral state, or a generating state to adjust the driving force or load (resistance) on the crankshaft so that the position of the piston in the expansion stroke cylinder of the engine when the engine is stopped is a preset stopping position. When the remaining battery charge is less than the lower limit, the restart motor is switched to either a neutral state or a generating state, and only the load on the output shaft is adjusted to adjust the stopping position of the piston. On the other hand, when the remaining battery charge is greater than the upper limit, the restart motor is activated to extend the predetermined time for driving the crankshaft.

Patent Document 3 also describes an engine drive device that aims to restart the engine even when the output of the starting motor is reduced. The engine drive device described in Patent Document 3 targets an engine configured such that when one of a plurality of cylinders is in a compression stroke, the other cylinder is in an expansion stroke, and performs pre-restart control by applying torque to the crankshaft by the starting motor until the exhaust valve of the cylinder in the expansion stroke opens before restarting the engine. Specifically, the engine drive device described in Patent Document 3 detects the temperature of the starting motor and the deterioration level of the battery, and performs pre-restart control when the temperature and deterioration level are in a first range, and does not perform pre-restart control when the temperature and deterioration level are in a second range smaller than the first range. Furthermore, when the temperature and deterioration level are in a third range larger than the first range, the engine idling stop is not performed, and the pre-restart control is not performed either.

JP 2012-126269 A JP 2006-170068 A JP 2020-200798 A

In the control device for a hybrid vehicle described in the above Patent Document 1, the engine in the hybrid vehicle is automatically stopped and restarted. When the engine is automatically stopped, the motor is powered to stop the crankshaft within a target stop range (i.e., engine stop position control is executed), thereby reducing torque and vibration when restarting the engine and improving startability. However, since the rotational position of the crankshaft is adjusted by powering the motor, the stop time when the engine is stopped cannot be shortened. In contrast, the motor is regenerated when the engine stop position control is executed to brake the rotation of the crankshaft, so that the engine can be stopped quickly and accurately. As shown in the time chart of FIG. 1, when the motor is regenerated to stop the engine (dashed line), the stop time can be shortened compared to when the engine is stopped naturally without motor control or when the motor is powered to stop the engine (solid line). In addition, by shortening the stop time, the engine speed Ne can be reduced by quickly passing through the rotation speed range (or frequency range) where resonance is likely to occur. Therefore, the occurrence of resonance when the engine is stopped can be suppressed, and the engine can be stopped smoothly.

However, depending on the state of the battery that exchanges power with the motor, the motor may not be able to regenerate, and the engine stop position control described above may not be able to be executed properly. For example, if the motor has been in a regenerative state for the previous drive and the battery does not have any extra chargeable power (remaining chargeable capacity), the motor cannot be regenerated to stop the engine. Therefore, as shown by the arrow in the time chart of FIG. 1, it is ultimately impossible to shorten the engine stop time. And because the rotational position of the crankshaft cannot be adjusted by the regenerative torque of the motor, engine stop position control cannot be executed when the engine is automatically stopped, and the crankshaft cannot be stopped accurately within the target stop range. As a result, the startability of the engine is reduced when it is restarted.

This invention was conceived with a focus on the above technical problems, and aims to provide a control device for a hybrid vehicle that can appropriately automatically stop and restart the engine, for hybrid vehicles that perform engine stop position control using the regenerative torque of a motor connected to the engine crankshaft.

To achieve the above object, the present invention provides a control device for a hybrid vehicle that includes an engine, a motor that is connected to the crankshaft of the engine so as to be capable of transmitting power and is driven by the output torque of the engine to generate electricity, and a battery that can supply and receive power from the motor, and that performs automatic stopping and restarting of the engine, and includes a controller that controls the engine and the motor, and that, when performing the automatic stopping, performs engine stop position control that regenerates the motor to apply a braking torque to the crankshaft and stops the crankshaft at a predetermined target stop position, and the controller obtains an allowable charging power as the power allowed for charging the battery, and prohibits the execution of the automatic stopping when the allowable charging power is smaller than a predetermined reference power amount.

The controller in this invention may also be configured to set a time interval during which the execution of the automatic stop is prohibited before prohibiting the execution of the automatic stop.

On the other hand, the present invention may be a control device for a hybrid vehicle that includes an engine, a motor that is connected to the crankshaft of the engine so as to be capable of transmitting power and is driven by the output torque of the engine to generate electricity, and a battery that can supply and receive power from the motor, and that performs automatic stopping and restarting of the engine, and includes a controller that controls the engine and the motor, and that, when performing the automatic stopping, performs engine stop position control by regenerating the motor to apply a braking torque to the crankshaft and stopping the crankshaft at a predetermined target stop position, and the controller calculates battery damage that quantitatively estimates the deterioration state of the battery based on the current value of the battery, and prohibits the execution of the automatic stopping when the battery damage is greater than a predetermined reference damage amount.

The controller of the present invention may also be configured to set a time interval for prohibiting the execution of the automatic stop based on the battery damage before prohibiting the execution of the automatic stop.

Furthermore, the present invention relates to a control device for a hybrid vehicle that includes an engine, a motor that is connected to the crankshaft of the engine and is driven by the output torque of the engine to generate electricity, and a battery that can supply and receive power from the motor, and that performs automatic stopping and restarting of the engine, and includes a controller that controls the engine and the motor, and that, when performing the automatic stopping, performs engine stop position control that regenerates the motor to apply a braking torque to the crankshaft and stops the crankshaft at a predetermined target stop position, and that calculates battery damage that quantitatively estimates the deterioration state of the battery based on the current value of the battery, and may be characterized in that, prior to performing the automatic stopping, the controller calculates battery damage that quantitatively estimates the deterioration state of the battery, and sets a time interval for prohibiting the execution of the automatic stopping based on the battery damage in advance.

The controller in this invention may be configured to lengthen the time interval as the battery damage increases.

The hybrid vehicle controlled by this invention has an engine and a motor as driving power sources. It also has a battery that receives and transmits power to the motor, that is, supplies power to the motor, and is charged (stores) with regenerative power generated by the motor. The motor is connected to the crankshaft of the engine so that it can transmit power, and is driven by the output torque of the engine to generate power. In other words, when the motor receives the output torque of the engine and regenerates power, it applies a regenerative torque (braking torque) to the crankshaft and brakes the rotation of the crankshaft. The control device of the hybrid vehicle of this invention automatically stops and restarts the engine, for example, when idling stop or switching between driving modes. When automatically stopping the engine, engine stop position control is executed. The engine stop position control brakes the crankshaft of the engine with the regenerative torque of the motor, stops the rotation of the crankshaft so that the rotation position of the crankshaft falls within a predetermined target stop position range, and stops the operation of the engine. This allows the engine to be automatically stopped quickly and smoothly. It also improves engine startability when restarting the engine.

Furthermore, the hybrid vehicle control device of the present invention prohibits the automatic engine stop from being executed when the battery's allowable charging power (input limit) is smaller than a reference power amount that sets the lower limit of the battery's input limit. When the battery's allowable charging power is small and the motor's regenerative power cannot be charged, engine stop position control using the motor's regenerative torque cannot be executed. If the engine is automatically stopped in such a state, it may not be possible to reliably stop the crankshaft within the target stop position range, and subsequent restart may not be executed properly. Therefore, in the hybrid vehicle control device of the present invention, when the battery's allowable charging power is small and engine stop position control using the motor's regenerative torque cannot be executed, the automatic engine stop is prohibited from being executed. This makes it possible to avoid failure of engine stop position control.

In addition, when the hybrid vehicle control device of the present invention prohibits the execution of automatic engine stop as described above, a time interval during which the execution of automatic engine stop is prohibited is set in advance before the execution of the automatic engine stop is prohibited. In other words, a time interval during which the automatic engine stop can be executed is set in advance. Therefore, by prohibiting the execution of automatic engine stop based on the battery's allowable charging power and setting a time interval during which the execution of the automatic engine stop is prohibited in advance, it is possible to avoid the automatic engine stop being prohibited for a long period of time.

On the other hand, the control device for a hybrid vehicle of the present invention prohibits the automatic engine stop from being executed when the battery damage of the battery is greater than the reference damage amount. Battery damage is an index that quantitatively estimates the deterioration state of the battery based on the battery current value. When the battery damage is great and the battery deterioration progresses, the battery's charging allowable power becomes small, and there are cases where the battery cannot charge the regenerative power of the motor. If the engine is automatically stopped in such a state, it may not be possible to reliably stop the crankshaft within the target stop position range, and subsequent restart may not be executed properly. Therefore, in the control device for a hybrid vehicle of the present invention, when the battery damage of the battery is great and there is a possibility that engine stop position control using the regenerative torque of the motor cannot be executed, execution of automatic engine stop is prohibited. Therefore, it is possible to avoid failure of engine stop position control.

In addition, when the hybrid vehicle control device of the present invention prohibits the execution of automatic engine stop as described above, a time interval during which the execution of automatic engine stop is prohibited is set in advance before the execution of the automatic engine stop is prohibited. In other words, a time interval during which the execution of automatic engine stop can be executed is set in advance. Therefore, by prohibiting the execution of automatic engine stop based on battery damage and setting a time interval during which the execution of the automatic stop is prohibited in advance, it is possible to avoid the automatic engine stop being prohibited for a long period of time.

Furthermore, when the control device for a hybrid vehicle of the present invention performs an automatic engine stop, a time interval during which the execution of the automatic engine stop is prohibited is set in advance before the automatic engine stop is executed. In other words, a time interval during which the automatic engine stop can be executed is set in advance. Therefore, by setting a time interval during which the execution of the automatic engine stop is prohibited in addition to executing the automatic engine stop, it is possible to avoid the automatic engine stop being prohibited for a long period of time.

In the hybrid vehicle control device of the present invention, the time interval for prohibiting the execution of automatic engine stop is set based on the battery damage. For example, the greater the battery damage, the longer the time interval is set. When engine stop position control is performed using the regenerative torque of the motor, the regenerative power of the motor that is charged to the battery is small, so there are few cases in which the battery becomes fully charged by executing engine stop position control. On the other hand, if the battery damage becomes large, there is a concern that it may cause problems with charging the battery. In the hybrid vehicle control device of the present invention, the time interval for prohibiting the execution of automatic engine stop based on the battery damage is preset, so that the execution of automatic engine stop and the control for prohibiting the execution of the automatic engine stop can be appropriately performed in accordance with the actual battery state.

Therefore, the hybrid vehicle control device of this invention can appropriately perform automatic engine stopping and restarting for a hybrid vehicle that performs engine stop position control using the regenerative torque of a motor connected to the engine crankshaft.

FIG. 1 is a time chart for explaining problems with engine stop position control of the prior art, showing an image comparing the engine stop time when engine stop position control is executed using the regenerative torque of a motor with the engine stop time when engine stop position control is executed naturally (or using the powering torque of a motor). FIG. 1 is a diagram for explaining a hybrid vehicle that is an object of control in the present invention, showing an example of the configuration and control system of the hybrid vehicle. FIG. 4 is a flow chart for explaining the control executed by the control device for a hybrid vehicle of the present invention, showing the control for determining whether or not to prohibit the automatic stop of the engine based on the allowable charging power of the battery. FIG. 2 is a flow chart for explaining the control executed by the control device for a hybrid vehicle of the present invention, showing the control for determining whether or not to prohibit the automatic stop of the engine based on the battery damage. FIG. 2 is a diagram for explaining the control executed by the control device for a hybrid vehicle of the present invention, showing the relationship between the charge allowable power and battery damage, a reference damage amount, etc.; FIG. 1 is a flowchart for explaining the control executed by the control device of the hybrid vehicle of the present invention, showing the control for setting a time interval (engine stop interval time) for prohibiting automatic engine stop based on battery damage. FIG. 13 is a diagram for explaining the control executed by the control device for a hybrid vehicle of the present invention, and is a diagram showing the time interval (engine stop interval time) that is set to a large value depending on battery damage, etc.

The embodiment of the present invention will be described with reference to the drawings. Note that the embodiment shown below is merely an example of how the present invention can be realized, and is not intended to limit the present invention.

The vehicle to be controlled in this embodiment of the invention is a hybrid vehicle equipped with an engine and a motor as driving power sources. The motor is connected to the crankshaft of the engine so that it can transmit power, and is configured to be driven by the output torque of the engine to generate electricity. The motor is also equipped with a battery that can supply and receive power to the motor. Figure 2 shows an overview of the configuration of a hybrid vehicle to be controlled in this embodiment of the invention.

The vehicle Ve shown in FIG. 2 is a hybrid vehicle equipped with a hybrid system known as a mild hybrid or 48V hybrid, and is equipped with an engine (ENG) 1 and a motor (MG) 2 as driving power sources. The vehicle Ve also has a high-voltage battery (High-Voltage Battery) 3 and an automatic transmission (T/M) 4. The vehicle Ve also has a detection unit 5 and a controller (ECU) 6 to execute various controls.

Engine 1 is an internal combustion engine, such as a gasoline engine or a diesel engine, that burns fuel to obtain power (mechanical energy). Engine 1 is configured so that the output adjustment and operating states such as starting and stopping are electrically controlled. In the case of a gasoline engine, the throttle valve opening, the amount of fuel supplied or injected, the on/off of ignition, and the ignition timing are electrically controlled. In the case of a diesel engine, the fuel injection amount, fuel injection timing, or the throttle valve opening in the EGR system are electrically controlled.

The motor 2 is connected to the crankshaft 1a of the engine 1 so as to be capable of transmitting power. Therefore, the motor 2 is configured to be driven by the output torque of the engine 1 and to generate electricity through regeneration. In the example shown in FIG. 2, the motor 2 is a so-called motor generator used in the above-mentioned mild hybrid system or 48V hybrid system, and functions as a starter motor that cranks the engine 1, an assist motor that assists the output of the engine 1, and a generator (generator or alternator).

2, the motor 2 transmits the torque output by the motor 2 to the engine 1 via the belt transmission mechanism 7 to crank the engine 1. The belt transmission mechanism 7 is a winding transmission mechanism consisting of a pulley and a transmission belt wound around the pulley. The belt transmission mechanism 7 is composed of a large-diameter pulley 7a integrally attached to the crankshaft 1a of the engine 1, a small-diameter pulley 7b integrally attached to the output shaft 2a of the motor 2, and a transmission belt 7c wound around the pulleys 7a and 7b. In the example shown in FIG. 2, an air conditioner compressor (A/C Compressor) 8 is connected to the engine 1 by a belt transmission mechanism 9 similar to the belt transmission mechanism 7. The belt transmission mechanism 7 and the belt transmission mechanism 9 may be configured as a so-called multi-shaft transmission, in which the transmission belt 7c is shared and the power is transmitted integrally.

The high-voltage battery 3 corresponds to the "battery" in the embodiment of the present invention, and is electrically connected to the motor 2 so that it can supply and receive power to and from the motor 2. The high-voltage battery 3 is a secondary battery, for example, a lithium-ion battery with a rated voltage of 48V, and supplies power to the motor 2 when the vehicle Ve starts or accelerates. The torque output by the motor 2 assists the driving force of the vehicle Ve. The high-voltage battery 3 is charged by the power generated by the motor 2 when the vehicle Ve decelerates. In the example shown in FIG. 2, the power generated by the motor 2 is converted in voltage by a DC/DC converter (DC/DC) 10, and charges a low-voltage battery 11 with a rated voltage of, for example, 12V. The low-voltage battery 11 is a secondary battery such as a lead-acid battery that has been commonly used in the past, and supplies power to a starter motor 12 and accessories 13. The starter motor 12 is a motor commonly used for starting engines, and is driven by power supplied from the low-voltage battery 11 to crank the engine 1.

The automatic transmission 4 is connected to the output side of the engine 1 via a torque converter (not shown). The automatic transmission 4 changes the rotation speed of the engine 1 and transmits the torque output by the engine 1 to drive wheels (not shown) via a drive shaft (not shown) or the like. The automatic transmission 4 is a conventional and commonly used vehicle transmission, for example a stepped (stepped) automatic transmission that controls the power transmission state between multiple planetary gear mechanisms (not shown). Alternatively, it may be another type of transmission, such as a belt-type continuously variable transmission or a dual clutch transmission.

Note that in a vehicle Ve equipped with a 48V mild hybrid system such as the example shown in FIG. 2, normal running using only the output of the motor 2 is not assumed. However, for example, when the vehicle Ve starts moving or runs at very low speeds, it is possible to perform so-called creep running using only the output of the motor 2, or similar running at very low speeds and low loads. Therefore, in this embodiment of the invention, the motor 2 as described above is also considered to be a driving force source in a broad sense. Furthermore, the vehicle Ve in this embodiment of the invention is not limited to the vehicle Ve configured as shown in FIG. 2, but may be a hybrid vehicle of another configuration that includes an engine 1 and a motor 2 (motor generator) connected to the crankshaft 1a of the engine 1 so as to be capable of transmitting power.

The detection unit 5 is a device or apparatus for acquiring various data and information required for controlling the vehicle Ve, and includes, for example, a power supply unit, a microcomputer, a sensor, and an input/output interface. In particular, the detection unit 5 in this embodiment of the present invention detects data for controlling the engine 1 and the motor 2. For example, the detection unit 5 has various sensors and devices such as an engine speed sensor 5a for detecting the rotation speed of the engine 1, a motor speed sensor 5b for detecting the rotation speed of the motor 2, a battery current sensor 5c for detecting the current value of the high-voltage battery 3, an SOC sensor 5d for detecting the state of charge (SOC) of the high-voltage battery 3, a battery temperature sensor 5e for detecting the temperature of the high-voltage battery 3, and a timer 5f for measuring the elapsed time of the control content. The detection unit 5 is electrically connected to the controller 6 described later, and outputs an electric signal corresponding to the detection value or the calculated value of the various sensors, devices, and apparatuses as described above to the controller 6 as detection data.

The controller 6 is, for example, an electronic control device mainly composed of a microcomputer, and mainly controls the operation of the engine 1 and the motor 2. Various data detected or calculated by the above-mentioned detection unit 5 is input to the controller 6. The controller 6 performs calculations using the various input data and pre-stored data, calculation formulas, etc. The controller 6 then outputs the calculation results as control command signals, and is configured to control the operation of the engine 1 and the motor 2, etc., as described above. In particular, the controller 6 in this embodiment of the present invention performs automatic stopping and restarting of the engine 1, for example, when idling stop of the engine 1 or when switching the driving mode of the vehicle Ve.

When the engine 1 is automatically stopped with the vehicle Ve as the control target, the controller 6 executes engine stop position control. In the engine stop position control, the motor 2 is driven as a generator, and the crankshaft 1a of the engine 1 is braked by the regenerative torque (i.e., braking torque) of the motor 2 generated at that time, so that the rotational position of the crankshaft 1a falls within a predetermined target stop position range, and the rotation of the crankshaft 1a is stopped. In other words, the operation of the engine 1 is stopped. By executing this engine stop position control with the regenerative torque of the motor 2, the engine can be automatically stopped quickly and smoothly. And, by stopping the crankshaft 1a within the target stop position range by the engine stop position control, the engine 1 can be restarted smoothly, and the startability at the time of restarting the engine 1 can be improved. Note that only one controller 6 is illustrated in FIG. 2, but multiple controllers 6 may be provided for each device or equipment to be controlled, or for each control content.

As described above, the control device for a hybrid vehicle in this embodiment of the invention is configured for the purpose of appropriately automatically stopping and restarting the engine 1 for a vehicle Ve that executes engine stop position control using the regenerative torque of the motor 2 as described above. An example of the control executed by the controller 6 for this purpose is shown in the flowchart of FIG. 3.

In the flowchart of FIG. 3, first, in step S1, the allowable charging power of the high-voltage battery 3 is calculated. The allowable charging power is the input limit of the power allowed for charging the high-voltage battery 3, and the high-voltage battery 3 can be charged by the remaining allowable charging power. As with conventional control technology, the allowable charging power can be calculated based on the detected temperature and SOC of the high-voltage battery 3. The allowable charging power is also called the "charge limit power," "input limit," "Win," etc., and may be expressed as a negative number. However, in the description of the embodiment of this invention, the allowable charging power is treated as an absolute value, and is expressed as a positive number in the graph of FIG. 5 described later, for example.

In step S2, it is determined whether the calculated allowable charging power is smaller than a reference power amount. The reference power amount is a threshold value for determining whether the regenerative power of the motor 2 can be charged to the high-voltage battery 3 based on the calculated allowable charging power. The reference power amount is determined in advance based on the results of experiments, simulations, etc. If the allowable charging power is equal to or greater than the reference power amount, it is determined that the regenerative power of the motor 2 can be charged to the high-voltage battery 3, that is, engine stop position control can be performed with the regenerative torque of the motor 2.

Therefore, if the charging allowable power is equal to or greater than the reference power amount and the result of step S2 is negative, the process proceeds to step S3, where the execution of automatic stopping of engine 1 is permitted. Then, if the state permitting the execution of automatic stopping of engine 1 is set or continues in step S3, the routine shown in the flowchart of FIG. 3 is temporarily terminated.

On the other hand, if the charging allowable power is smaller than the reference power amount and thus the answer is affirmative in step S2, the process proceeds to step S4, where the execution of automatic stopping of engine 1 is prohibited. Then, if the state in which the execution of automatic stopping of engine 1 is prohibited is set or continues in step S4, the routine shown in the flowchart of FIG. 3 is temporarily terminated.

On the other hand, in the hybrid vehicle control device according to the embodiment of the present invention, it is also possible to control the engine 1 to determine whether to prohibit automatic stopping based on battery damage to the high-voltage battery 3, as shown in the flowchart in Figure 4 below.

In the flowchart of FIG. 4, first, in step S11, the battery damage of the high-voltage battery 3 is calculated. The battery damage is a value that quantitatively estimates the degradation state of the high-voltage battery 3 based on the current value of the high-voltage battery 3. When the degradation of the high-voltage battery 3 progresses and the value of the battery damage increases, the power allowed for charging the high-voltage battery 3 is limited, and the allowable charging power becomes smaller. Therefore, in the control shown in the flowchart of FIG. 4, when the battery damage is large, the automatic stop of the engine 1 is prohibited.

Note that, similar to conventional control technology, battery damage can be calculated based on the current value of electricity input/output to/from the high-voltage battery 3. For example, the specification of JP 2021-93258 A describes a method for calculating the "amount of damage" of a battery caused by bias in the salt concentration in the battery based on the current value of electricity input/output to/from the battery and the duration of current flow, as well as the "degree of deterioration" of the battery calculated using an integrated value of the "amount of damage." Similar to such known control technology, or with reference to known control technology, battery damage (amount of damage) in an embodiment of the present invention can be calculated.

In step S12, it is determined whether the calculated battery damage is greater than a reference damage amount. The reference damage amount is a threshold value for determining whether the regenerative power of the motor 2 can be charged to the high-voltage battery 3, based on the calculated battery damage. The reference damage amount is determined in advance based on the results of experiments, simulations, etc. If the battery damage is less than the reference damage amount, it is determined that the regenerative power of the motor 2 can be charged to the high-voltage battery 3, that is, engine stop position control can be performed with the regenerative torque of the motor 2.

Therefore, if the battery damage is less than the reference damage amount and the result of step S12 is negative, the process proceeds to step S13, where the execution of automatic stopping of the engine 1 is permitted. Then, if the state permitting the execution of automatic stopping of the engine 1 is set or continues in step S13, the routine shown in the flowchart of FIG. 4 is temporarily terminated.

On the other hand, if the battery damage is greater than the reference damage amount and a positive determination is made in step S12, the process proceeds to step S14, and execution of automatic stopping of engine 1 is prohibited. Then, if a state permitting execution of automatic stopping of engine 1 is set or continues in step S14, the routine shown in the flowchart of FIG. 4 is temporarily terminated.

As described above, when the deterioration of the high voltage battery 3 progresses and the value of the battery damage increases, the charging allowable power of the high voltage battery 3 decreases. At the same time, since the battery damage is the result of long-term accumulation, once the battery damage exceeds a predetermined amount of damage and the charging allowable power decreases, it takes a long time for the charging allowable power to recover. For example, as shown in FIG. 5, when the prohibition of the automatic stop of the engine 1 is judged based on the battery damage, the above-mentioned reference damage amount d ₁ is set as the judgment threshold at that time. In addition, in order to avoid hunting of the control, a reference damage amount d ₂ (d ₂ <d ₁ ) having hysteresis in the direction of releasing the prohibition of the automatic stop may be set for the reference damage amount d _1. In such a case, when the battery damage exceeds the reference damage amount d ₁ and the automatic stop of the engine 1 is prohibited, it takes even more time for the battery to recover from the damage and the prohibition of the automatic stop to be released.

In the hybrid vehicle control device according to the embodiment of the present invention, in addition to determining whether to prohibit the automatic stopping of the engine 1 based on the charge allowable power or battery damage of the high-voltage battery 3, if the automatic stopping is to be prohibited, a time interval (period) for prohibiting the execution of the automatic stopping is set in advance before the execution of the automatic stopping is prohibited. The following flowchart in Figure 6 shows an example of control for determining whether to prohibit the automatic stopping of the engine 1 based on battery damage to the high-voltage battery 3 and setting a time interval for prohibiting the execution of the automatic stopping of the engine 1.

In the flowchart of FIG. 6, first, in step S21, the battery damage of the high-voltage battery 3 is calculated. As described above, the battery damage can be calculated based on the current value of electricity input and output to the high-voltage battery 3, similar to conventional control technology.

In step S22, an engine stop interval is calculated. The engine stop interval is a time interval during which the execution of automatic stopping of the engine 1 is prohibited. When this engine stop interval is set, when the execution of automatic stopping of the engine 1 is prohibited based on the charging allowable power or battery damage of the high-voltage battery 3, the execution of the automatic stopping is prohibited for a period until the engine stop interval has elapsed. That is, in the control shown in the flowchart of FIG. 6, a time interval during which the execution of automatic stopping of the engine 1 is prohibited (engine stop interval) is set in advance prior to the control for prohibiting the execution of automatic stopping of the engine 1 in step S24 described later.

The engine stop interval (the time interval during which execution of automatic stopping of the engine 1 is prohibited) may be set to change according to the degree of battery damage. As shown in FIG. 5 above, the charging allowable power (Win) of the high-voltage battery 3 is almost constant while the battery damage is small. However, when the battery damage increases and exceeds a predetermined damage amount _d0 , the charging allowable power decreases (approaches 0) as the battery damage increases. Based on such characteristics of the high-voltage battery 3, the engine stop interval may be set to be longer as the battery damage increases in the region where the battery damage exceeds the damage amount _d0 , as shown in FIG. 7.

In step S23, it is determined whether the engine ON time is shorter than the engine stop interval time. The engine ON time is the time during which the engine 1 is continuously operating. While this engine ON time is shorter than the engine stop interval time, execution of automatic stopping of the engine 1 is prohibited. In other words, execution of automatic stopping of the engine 1 is prohibited until the time during which the engine 1 is continuously operating reaches the engine stop interval time.

Therefore, if the engine ON time is shorter than the engine stop interval time and thus the answer is YES in step S23, the process proceeds to step S24, where execution of automatic stopping of engine 1 is prohibited. In other words, execution of automatic stopping of engine 1 is prohibited and continuous operation of engine 1 continues until the engine stop interval time has elapsed. Then, if a state in which execution of automatic stopping of engine 1 is prohibited is set or continues in step S24, the routine shown in the flowchart of FIG. 6 is temporarily terminated.

On the other hand, if the engine ON time is equal to or longer than the engine stop interval time and therefore step S23 returns a negative answer, the process proceeds to step S25, where execution of automatic stopping of engine 1 is permitted. In other words, the engine stop interval time has elapsed, and execution of automatic stopping of engine 1 is permitted, making it possible to automatically stop engine 1. Then, in step S245, when the state permitting execution of automatic stopping of engine 1 is set or continues, the routine shown in the flowchart of FIG. 6 is temporarily terminated.

The control shown in the flowchart of FIG. 6 above may be executed in parallel with the control shown in the flowchart of FIG. 3 or the flowchart of FIG. 4, or in combination with the control shown in the flowchart of FIG. 4. Alternatively, the controls shown in each flowchart may be executed individually or selectively.

For example, the control contents shown in the flowchart of FIG. 3 may be combined with part of the control contents shown in the flowchart of FIG. 6 to execute control such that "prior to prohibiting the execution of automatic engine stop according to the allowable charging power of the battery, a time interval for prohibiting the execution of automatic engine stop is set in advance."

Alternatively, a part of the control contents shown in the flowchart of FIG. 6 may be excerpted and the control may be executed so that "based on battery damage that is a quantitative estimate of the deterioration state of the battery, a time interval for prohibiting the execution of automatic engine stop is set in advance before the execution of automatic engine stop."

As described above, in the control device for a hybrid vehicle in the embodiment of the present invention, when the charging allowable power of the high-voltage battery 3 is small and engine stop position control by the regenerative torque of the motor 2 cannot be executed, or when the battery damage of the high-voltage battery 3 is large and there is a possibility that engine stop position control by the regenerative torque of the motor 2 cannot be executed, execution of automatic stopping of the engine 1 is prohibited. Therefore, it is possible to avoid a failure of engine stop position control due to automatic stopping of the engine 1. Furthermore, in the control device for a hybrid vehicle in the embodiment of the present invention, when the execution of automatic stopping of the engine 1 is prohibited as described above, a time interval for prohibiting the execution of the automatic stopping is preset. By setting such a time interval based on the battery damage of the high-voltage battery 3, it is possible to appropriately avoid the automatic stopping of the engine being prohibited for a long period of time.

Therefore, the hybrid vehicle control device according to the embodiment of the present invention can appropriately automatically stop and restart the engine 1 for the vehicle Ve that performs engine stop position control using the regenerative torque of the motor 2 connected to the crankshaft 1a of the engine 1.

1. Engine (ENG)
1a (engine) crankshaft 2 motor (MG)
2a (Motor) Output Shaft 3 High-Voltage Battery
4. Automatic transmission (T/M)
5 Detection unit 5a (detection unit) engine speed sensor 5b (detection unit) motor speed sensor 5c (detection unit) battery current sensor 5d (detection unit) SOC sensor 5e (detection unit) battery temperature sensor 5f (detection unit) timer 6 Controller (ECU)
7 Belt transmission mechanism 7a (of the belt transmission mechanism) large diameter pulley 7b (of the belt transmission mechanism) small diameter pulley 7c (of the belt transmission mechanism) transmission belt 8 Compressor (A/C Compressor)
9 Belt transmission mechanism (for compressor) 10 DC/DC converter (DC/DC)
11. Low-Voltage Battery
12 Starter motor
13 Accessories
Ve vehicle (hybrid vehicle)

Claims (6)

A control device for a hybrid vehicle, comprising: an engine; a motor connected to a crankshaft of the engine and capable of generating electricity by being driven by an output torque of the engine; and a battery capable of supplying and receiving electric power to the motor, the control device automatically stopping and restarting the engine,
a controller that controls the engine and the motor, and executes an engine stop position control that, when performing the automatic stop, causes the motor to regenerate and applies a braking torque to the crankshaft to stop the crankshaft at a predetermined target stop position;
The controller:
obtaining a charging allowable power as a power allowable for charging the battery;
A control device for a hybrid vehicle, comprising: a control unit for controlling a hybrid vehicle, the control unit for controlling the hybrid vehicle being stopped automatically when the allowable charging power is smaller than a predetermined reference power amount. The control device for a hybrid vehicle according to claim 1,
The controller:
13. A control device for a hybrid vehicle, comprising: a control unit for controlling a hybrid vehicle, the control unit setting a time interval during which execution of the automatic stop is prohibited before prohibiting execution of the automatic stop. A control device for a hybrid vehicle, comprising: an engine; a motor connected to a crankshaft of the engine and capable of generating electricity by being driven by an output torque of the engine; and a battery capable of supplying and receiving electric power to the motor, the control device automatically stopping and restarting the engine,
a controller that controls the engine and the motor, and executes an engine stop position control that, when performing the automatic stop, causes the motor to regenerate and applies a braking torque to the crankshaft to stop the crankshaft at a predetermined target stop position;
The controller:
Calculating battery damage by estimating a deterioration state of the battery based on a current value of the battery;
A control device for a hybrid vehicle, comprising: a control unit for controlling a hybrid vehicle, the control unit for controlling a hybrid vehicle being driven; and a control unit for controlling a hybrid vehicle being driven. The control device for a hybrid vehicle according to claim 3,
The controller:
4. A control device for a hybrid vehicle, comprising: a control unit for controlling a hybrid vehicle, the control unit setting a time interval for prohibiting execution of the automatic stop based on the battery damage, prior to prohibiting execution of the automatic stop. A control device for a hybrid vehicle, comprising: an engine; a motor connected to a crankshaft of the engine and capable of generating electricity by being driven by an output torque of the engine; and a battery capable of supplying and receiving electric power to the motor, the control device automatically stopping and restarting the engine,
a controller that controls the engine and the motor, and executes an engine stop position control that, when performing the automatic stop, causes the motor to regenerate and applies a braking torque to the crankshaft to stop the crankshaft at a predetermined target stop position;
The controller:
Calculating battery damage by estimating a deterioration state of the battery based on a current value of the battery;
4. A control device for a hybrid vehicle, comprising: a control unit for controlling a hybrid vehicle, the control unit setting a time interval for prohibiting execution of the automatic stop based on the battery damage, prior to executing the automatic stop. The control device for a hybrid vehicle according to claim 4 or 5,
The controller:
A control device for a hybrid vehicle, characterized in that the greater the battery damage, the longer the time interval.

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