Hybrid vehicle control device

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

[Technical Field]

[0001] The present invention relates to a control device for a hybrid vehicle equipped with an engine (internal combustion engine) and a motor as driving power sources. [Background technology]

[0002] Patent Document 1 describes a control device for a hybrid vehicle that controls the crankshaft to stop within a predetermined target stopping range when stopping the engine, 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 crankshaft stops within the target stopping range if the battery's remaining capacity (SOC) is equal to or greater than a determination threshold. When the battery's SOC is less than the determination threshold, the control device controls the engine's valve mechanism so that the crankshaft stops within the target stopping range.

[0003] Patent Document 2 describes a vehicle control device that aims to improve engine restart performance while maintaining an appropriate remaining battery charge. When an automatic engine stop condition is met and fuel supply is stopped, the vehicle control device described in Patent Document 2 activates a 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 piston position in the expansion stroke cylinder of the engine when the engine is stopped is a preset stopping position. When the remaining battery charge is lower than a 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 higher than an upper limit, the restart motor is activated to extend the predetermined time for driving the crankshaft.

[0004] Furthermore, Patent Document 3 describes an engine drive device that aims to restart the engine even when the output of the starting motor is reduced. This engine drive device, targeted at an engine configured such that one of multiple cylinders is in the compression stroke while the other is in the expansion stroke, performs pre-restart control before restarting the engine, in which the starting motor applies torque to the crankshaft until the exhaust valve of the cylinder in the expansion stroke opens. Specifically, the engine drive device described in Patent Document 3 detects the temperature of the starting motor and the deterioration level of the battery. If the temperature and deterioration level are within a first range, the pre-restart control is performed, but if the temperature and deterioration level are within a second range that is lower than the first range, the pre-restart control is not performed. Furthermore, if the temperature and deterioration level are within a third range that is higher than the first range, the engine idling stop is not performed, and neither is the pre-restart control. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-126269 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-170068 [Patent Document 3] Japanese Patent Application Publication No. 2020-200798 Summary of the Invention [Problem to be solved by the invention]

[0006] The hybrid vehicle control device described in the aforementioned Patent Document 1 automatically stops and restarts the engine of a hybrid vehicle. When automatically stopping the engine, 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 during engine restart and improving startability. However, because the rotational position of the crankshaft is adjusted by powering the motor, the engine stop time cannot be shortened. In contrast, by regenerating the motor and braking the crankshaft rotation during engine stop position control, the engine can be stopped quickly and accurately. As shown in the time chart of FIG. 1 , when the engine is stopped by regenerating the motor (dashed line), the engine stop time can be shortened compared to when the engine is stopped naturally without motor control or when the engine is stopped by powering the motor (solid line). Furthermore, by shortening the stop time, the engine speed Ne can be reduced by quickly passing through a rotation speed range (or frequency range) where resonance is likely to occur. Therefore, resonance is suppressed when the engine is stopped, allowing the engine to be stopped smoothly.

[0007] 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 properly executed. For example, if the motor continued to regenerate power during the preceding driving session and the battery's chargeable power (remaining chargeable capacity) is insufficient, the motor cannot be regenerated to stop the engine. As a result, as shown by the arrow in the time chart of FIG. 1, it becomes impossible to shorten the engine stop time. Furthermore, because the rotational position of the crankshaft cannot be adjusted using the motor's regenerative torque, engine stop position control cannot be executed when the engine is automatically stopped, and the crankshaft cannot be accurately stopped within the target stop range. As a result, the startability of the engine when it is restarted is reduced.

[0008] This invention was devised with an eye on the above-mentioned technical problems, and aims to provide a control device for a hybrid vehicle that is capable of appropriately automatically stopping and restarting the engine, for a hybrid vehicle that performs engine stop position control using the regenerative torque of a motor connected to the engine crankshaft. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention provides a control device for a hybrid vehicle that includes an engine, a motor connected to the crankshaft of the engine and driven by the output torque of the engine to generate electricity, and a battery that can supply and receive electric power to the motor, and that performs automatic stopping and restarting of the engine, the control device including a controller that controls the engine and the motor and, when performing the automatic stopping, performs engine stop position control that causes the motor to regenerate electricity and applies braking torque to the crankshaft to stop the crankshaft at a predetermined target stop position, the controller obtains allowable charging power as power that is allowable 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. and before prohibiting the execution of the automatic stop, a time interval for prohibiting the execution of the automatic stop is set in advance. It is characterized by the above. [Effects of the Invention]

[0015] The hybrid vehicle controlled by this invention includes an engine and a motor as driving power sources. The vehicle also includes a battery that supplies power to the motor, i.e., that is charged (stores) with regenerative power generated by the motor. The motor is power-transmittably connected to the engine crankshaft and is driven by the engine's output torque to generate power. In other words, when the motor receives the engine's output torque and regenerates power, it applies regenerative torque (braking torque) to the crankshaft, braking the rotation of the crankshaft. The hybrid vehicle control device of this invention automatically stops and restarts the engine, for example, during an idling stop or when switching between driving modes. When automatically stopping the engine, it executes engine stop position control. The engine stop position control brakes the engine crankshaft with the motor's regenerative torque, stopping the rotation of the crankshaft so that the rotational position of the crankshaft falls within a predetermined target stop position range, thereby stopping the engine operation. This allows the engine to be automatically stopped quickly and smoothly. Furthermore, the startability of the engine can be improved when it is restarted.

[0016] Furthermore, the hybrid vehicle control device of the present invention prohibits the execution of automatic engine stop 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 were to be automatically stopped in such a state, it would be impossible to reliably stop the crankshaft within the target stop position range, and subsequent restart may not be properly executed. Therefore, the hybrid vehicle control device of the present invention prohibits the execution of automatic engine stop when the battery's allowable charging power is small and the motor's regenerative torque cannot be used to execute engine stop position control. This prevents engine stop position control from failing.

[0017] Furthermore, when the control device for a hybrid vehicle 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 prohibition of the execution of automatic engine stop. In other words, a time interval during which the execution of automatic engine stop is enabled is set in advance. Therefore, by prohibiting the execution of automatic engine stop based on the allowable charging power of the battery and setting the time interval during which the execution of automatic engine stop is prohibited in advance, it is possible to avoid the automatic engine stop being prohibited for a long period of time.

[0022] Therefore, according to the hybrid vehicle control device of the present invention, automatic stopping and restarting of the engine can be performed appropriately for hybrid vehicles that perform engine stop position control using the regenerative torque of a motor connected to the engine crankshaft. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a time chart illustrating the problems with engine stop position control of the prior art, comparing the engine stop time when engine stop position control is performed using the regenerative torque of the motor with the engine stop time when engine stop position control is performed naturally (or using the powering torque of the motor). [Figure 2] 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. [Figure 3] 4 is a flowchart for explaining the control executed by the control device for a hybrid vehicle of the present invention, and is a control flow for determining whether to prohibit automatic engine stop based on the allowable charging power of the battery. FIG. [Figure 4] FIG. 10 is a flowchart for explaining a reference example of control executed by a control device of a hybrid vehicle, showing control for determining prohibition of automatic engine stop based on battery damage. [Figure 5] FIG. 10 is a diagram for explaining a reference example of control executed by a control device of a hybrid vehicle, showing the relationship between allowable charging power and battery damage, a reference damage amount, etc. [Figure 6] FIG. 10 is a flowchart illustrating another example of control executed by a control device of a hybrid vehicle, showing control for setting a time interval (engine stop interval time) for prohibiting automatic stopping of the engine based on battery damage. [Figure 7] FIG. 10 is a diagram for explaining another reference example of control executed by a control device for a hybrid vehicle, showing time intervals (engine stop interval times) that are set to larger values ​​depending on battery damage, etc. DETAILED DESCRIPTION OF THE INVENTION

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are merely examples of specific embodiments of the present invention and are not intended to limit the scope of the present invention.

[0025] The vehicle to be controlled in this embodiment of the present invention is a hybrid vehicle equipped with an engine and a motor as driving power sources. The motor is connected to the engine crankshaft so that power can be transmitted and is configured to be driven by the engine's output torque to generate electricity. The motor is also equipped with a battery that can supply and receive power to the motor. Figure 2 shows an outline of the configuration of the hybrid vehicle to be controlled in this embodiment of the present invention.

[0026] 2 is a hybrid vehicle equipped with a hybrid system known as a mild hybrid or a 48V hybrid, and includes an engine (ENG) 1 and a motor (MG) 2 as driving power sources. The vehicle Ve also includes a high-voltage battery 3 and an automatic transmission (T / M) 4. The vehicle Ve also includes a detector 5 and a controller (ECU) 6 for executing various controls.

[0027] The engine 1 is an internal combustion engine, such as a gasoline engine or a diesel engine, that burns fuel to obtain power (mechanical energy). The engine 1 is configured so that its operating state, such as output adjustment, starting and stopping, etc., is electrically controlled. In the case of a gasoline engine, the throttle valve opening, the fuel supply or injection amount, ignition on / off, and ignition timing are electrically controlled. In the case of a diesel engine, the fuel injection amount, fuel injection timing, or throttle valve opening in the EGR system are electrically controlled.

[0028] The motor 2 is coupled 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 power generator (generator or alternator).

[0029] In the example shown in FIG. 2, the motor 2 transmits the torque output by the motor 2 to the engine 1 via a belt transmission mechanism 7 to crank the engine 1. The belt transmission mechanism 7 is a winding transmission mechanism made up of pulleys and a transmission belt wound around the pulleys. The belt transmission mechanism 7 is made up 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 also have a so-called multi-shaft transmission configuration in which they share the transmission belt 7c to transmit power together.

[0030] The high-voltage battery 3 corresponds to the "battery" in the embodiments of the present invention and is electrically connected to the motor 2 so as to be able to supply and receive electric power to the motor 2. The high-voltage battery 3 is a secondary battery, such as a lithium-ion battery with a rated voltage of 48 V, and supplies electric 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 with electric power generated by the motor 2 when the vehicle Ve decelerates. In the example shown in FIG. 2 , the electric 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 12 V, for example. The low-voltage battery 11 is a secondary battery, such as a commonly used lead-acid battery, and supplies electric power to a starter motor 12, accessories 13, and the like. The starter motor 12 is a conventional motor commonly used for starting an engine, and is driven by electric power supplied from the low-voltage battery 11 to crank the engine 1.

[0031] 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, commonly used vehicle transmission, and is, for example, a stepped (stepped) automatic transmission that controls the power transmission state between multiple planetary gear mechanisms (not shown). Alternatively, the automatic transmission 4 may be another type of transmission, such as a belt-type continuously variable transmission or a dual clutch transmission.

[0032] 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 generally anticipated. However, for example, when the vehicle Ve starts moving or when running at extremely low speeds, so-called creep running or similar extremely low-speed, low-load running using only the output of the motor 2 is possible. Therefore, in this embodiment of the present invention, the motor 2 as described above is also considered a driving power source in a broad sense. Furthermore, the vehicle Ve in this embodiment of the present 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.

[0033] The detection unit 5 is a device or apparatus for acquiring various data and information required to control the vehicle Ve, and includes, for example, a power supply unit, a microcomputer, sensors, 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 includes 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 control operations. The detection unit 5 is electrically connected to the controller 6 (described later) and outputs, as detection data, electrical signals corresponding to the detected or calculated values ​​of the various sensors, devices, and apparatuses described above to the controller 6.

[0034] The controller 6 is an electronic control device mainly composed of, for example, a microcomputer, and mainly controls the operations 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 input various data as well as pre-stored data, calculation formulas, etc. The controller 6 then outputs the calculation results as control command signals and is configured to control the operations of the engine 1 and the motor 2, etc., as described above. In particular, the controller 6 in this embodiment of the present invention executes automatic stopping and restarting of the engine 1, for example, when idling stop of the engine 1 is performed or when switching the driving mode of the vehicle Ve.

[0035] Furthermore, when the controller 6 controls the vehicle Ve as described above and automatically stops the engine 1, it executes engine stop position control. The engine stop position control involves driving the motor 2 as a generator, braking the crankshaft 1a of the engine 1 with the regenerative torque (i.e., braking torque) generated by the motor 2, and stopping the rotation of the crankshaft 1a so that the rotational position of the crankshaft 1a falls within a predetermined target stop position range. In other words, the operation of the engine 1 is stopped. By executing this engine stop position control using the regenerative torque of the motor 2, the engine can be automatically stopped quickly and smoothly. Furthermore, by stopping the crankshaft 1a within the target stop position range through the engine stop position control, the engine 1 can be restarted smoothly, improving the startability of the engine 1 when it is restarted. Although only one controller 6 is shown in FIG. 2 , multiple controllers 6 may be provided for each device or equipment to be controlled or for each control content.

[0036] As described above, the control device for a hybrid vehicle according to the embodiment of the present invention is configured to appropriately automatically stop and restart the engine 1 for the vehicle Ve that executes engine stop position control using the regenerative torque of the motor 2. An example of the control executed by the controller 6 for this purpose is shown in the flowchart of FIG.

[0037] 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 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. Note that the allowable charging power is also referred to as the "limit charging power," "input limit," or "Win," and may be expressed as a negative number. However, in the description of the embodiments of the present invention, the allowable charging power is treated as an absolute value, and is expressed as a positive number, for example, in the graph of FIG. 5 described below.

[0038] 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, it is determined that engine stop position control can be performed using the regenerative torque of the motor 2.

[0039] Therefore, if the charging allowable power is equal to or greater than the reference power amount and the result of the determination in step S2 is negative, the process proceeds to step S3, where execution of automatic stopping of the engine 1 is permitted. If the state in which execution of automatic stopping of the engine 1 is permitted is set or continues in step S3, the routine shown in the flowchart of Fig. 3 is temporarily terminated.

[0040] On the other hand, if the charging allowable power is smaller than the reference power amount and the answer to step S2 is affirmative, the process proceeds to step S4, where the execution of automatic stopping of the engine 1 is prohibited. If the state in which the execution of automatic stopping of the engine 1 is prohibited is set or continues in step S4, the routine shown in the flowchart of Fig. 3 is temporarily terminated.

[0041] on the other hand , Ha The control device for a hybrid vehicle can also perform control so as to determine whether or not to prohibit automatic stopping of the engine 1 based on battery damage to the high-voltage battery 3, as shown in the flowchart of FIG.

[0042] In the flowchart of FIG. 4, first, in step S11, battery damage to the high-voltage battery 3 is calculated. Battery damage is a value that quantitatively estimates the state of degradation of the high-voltage battery 3 based on the current value of the high-voltage battery 3. When degradation of the high-voltage battery 3 progresses and the value of 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 battery damage is significant, automatic stopping of the engine 1 is prohibited.

[0043] Similar to conventional control techniques, battery damage can be calculated based on the current value of electricity input and output to the high-voltage battery 3. For example, the specification of JP 2021-93258 A describes a method for calculating the "amount of damage" to a battery caused by an imbalance in the salt concentration in the battery based on the current value of electricity input and output to the battery and the duration of current flow, as well as a "level of deterioration" of the battery calculated using an integrated value of this "amount of damage." Similar to such known control techniques, or with reference to known control techniques, battery damage (amount of damage) in embodiments of the present invention can be determined.

[0044] 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 using the regenerative torque of the motor 2.

[0045] Therefore, if it is negatively determined in this step S12 because the battery damage is less than the reference damage amount, the process proceeds to step S13, and the execution of the automatic stop of the engine 1 is permitted. And when the state permitting the execution of the automatic stop of the engine 1 is set or continued in step S13, the routine shown in the flowchart of FIG. 4 is once terminated.

[0046] On the other hand, if it is positively determined in step S12 because the battery damage is greater than the reference damage amount, the process proceeds to step S14, and the execution of the automatic stop of the engine 1 is prohibited. And when the state permitting the execution of the automatic stop of the engine 1 is set or continued in step S14, the routine shown in the flowchart of FIG. 4 is once terminated.

[0047] As described above, as the deterioration of the high-voltage battery 3 progresses and the value of the battery damage increases, the charge allowable power of the high-voltage battery 3 decreases. At the same time, since the battery damage is the result of accumulation over a long period, when the battery damage exceeds a predetermined damage amount and once the charge allowable power decreases, it takes a long time for the charge allowable power to recover. For example, as shown in FIG. 5, when determining the prohibition of the automatic stop of the engine 1 based on the battery damage, the reference damage amount d1 as described above is set as the determination threshold value at that time. Also, with respect to the reference damage amount d1, in order to avoid hunting of control, a reference damage amount d2 (d2 < d1) having hysteresis in the direction of releasing the prohibition of the automatic stop may be set. In such a case, when the automatic stop of the engine 1 is prohibited because the battery damage exceeds the reference damage amount d1, it takes even more time until the battery damage recovers and the prohibition of the automatic stop is released.

[0048] Therefore ,highThe hybrid vehicle control device determines whether to prohibit automatic stopping of the engine 1 based on the allowable charging power or battery damage of the high-voltage battery 3, and if the automatic stopping is to be prohibited, sets a time interval (period) for prohibiting the automatic stopping before prohibiting the automatic stopping. The flowchart in Figure 6 shows an example of control that determines whether to prohibit automatic stopping of the engine 1 based on battery damage to the high-voltage battery 3, and sets a time interval for prohibiting the automatic stopping of the engine 1.

[0049] 6, first, in step S21, the battery damage to the high-voltage battery 3 is calculated. As described above, the battery damage can be calculated based on the current value of electricity input to and output from the high-voltage battery 3, similar to conventional control techniques.

[0050] In step S22, an engine stop interval is calculated. The engine stop interval is a time interval during which execution of automatic stopping of the engine 1 is prohibited. Once this engine stop interval is set, when execution of automatic stopping of the engine 1 is prohibited based on the allowable charging power of the high-voltage battery 3 or battery damage, execution of the automatic stopping of the engine 1 is prohibited for a period until the engine stop interval has elapsed. That is, in the control shown in the flowchart of FIG. 6, prior to control for prohibiting execution of automatic stopping of the engine 1 in step S24, which will be described later, a time interval during which execution of automatic stopping of the engine 1 is prohibited (engine stop interval) is set in advance.

[0051] The engine stop interval (the time interval during which execution of automatic engine 1 stop is prohibited) may be set to vary depending on the degree of battery damage. As shown in FIG. 5 above, the allowable charging power (Win) of the high-voltage battery 3 remains approximately constant while the battery damage is small. However, once the battery damage increases and exceeds a predetermined amount of damage d0, the allowable charging power decreases (approaching zero) 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 range where the battery damage exceeds the amount of damage d0, as shown in FIG. 7.

[0052] In step S23, it is determined whether the engine ON time is shorter than the engine stop interval. 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, 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.

[0053] Therefore, if the engine ON time is shorter than the engine stop interval and the answer to this step S23 is affirmative, the process proceeds to step S24, where execution of automatic stop of the engine 1 is prohibited. In other words, execution of automatic stop of the engine 1 is prohibited and continuous operation of the engine 1 continues until the engine stop interval has elapsed. Then, if a state in which execution of automatic stop of the engine 1 is prohibited is set or continues in this step S24, the routine shown in the flowchart of FIG. 6 is temporarily terminated.

[0054] On the other hand, if the engine ON time is equal to or longer than the engine stop interval and therefore the answer to step S23 is NO, the process proceeds to step S25, where execution of automatic stop of the engine 1 is permitted. In other words, the lapse of the engine stop interval permits execution of automatic stop of the engine 1, and a state is established in which automatic stopping of the engine 1 can be performed. Then, in step S245, if the state in which execution of automatic stop of the engine 1 is permitted is set or continues, the routine shown in the flowchart of FIG. 6 is temporarily terminated.

[0055] The control shown in the flowchart of Fig. 6 may be executed in parallel with or in combination with the control shown in the flowchart of Fig. 3 or the flowchart of Fig. 4. Alternatively, the controls shown in each flowchart may be executed independently or selectively.

[0056] 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 in accordance with the allowable charging power of the battery, a time interval for prohibiting the execution of automatic engine stop may be set in advance."

[0057] Alternatively, a part of the control contents shown in the flowchart of FIG. 6 may be extracted and the control may be executed so that "based on battery damage quantitatively estimated from 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."

[0058] As described above, in the control device for a hybrid vehicle according to the embodiment of the present invention, when the charge allowable power of the high voltage battery 3 is small and the engine stop position control using the regenerative torque of the motor 2 cannot be executed, In the eventWhen the automatic stop of the engine 1 is prohibited, the automatic stop of the engine 1 is prohibited. This makes it possible to avoid a situation where the automatic stop of the engine 1 is performed and the engine stop position control fails. Furthermore, in the control device for a hybrid vehicle according to the embodiment of the present invention, when the automatic stop of the engine 1 is prohibited as described above, a time interval for prohibiting the automatic stop is set in advance. By setting such a time interval based on battery damage to the high-voltage battery 3, it is possible to appropriately avoid the automatic stop of the engine being prohibited for a long period of time.

[0059] Therefore, according to the hybrid vehicle control device of this embodiment of the present invention, automatic stopping and restarting of the engine 1 can be appropriately performed 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. [Explanation of symbols]

[0060] 1 Engine (ENG) 1a (engine) crankshaft 2 motors (MG) 2a (Motor) output shaft 3 High-Voltage Battery 4 Automatic transmission (T / M) 5. Detection unit 5a (Detection section) Engine speed sensor 5b (detection part) motor rotation speed sensor 5c (Detection section) Battery current sensor 5d SOC sensor (detection section) 5e Battery temperature sensor (detection section) 5f (detector) timer 6 Controller (ECU) 7 Belt transmission mechanism 7a (Belt transmission mechanism) large diameter pulley 7b (belt transmission mechanism) small diameter pulley 7c Transmission belt (of a belt transmission mechanism) 8. Compressor (A / C Compressor) 9 Belt transmission mechanism (for compressors) 10 DC-DC converter (DC / DC) 11 Low-Voltage Battery 12 Starter motor 13 Accessories Vehicle (hybrid vehicle)

Claims

[Claim 1] A control device for a hybrid vehicle that includes an engine, a motor that is connected to a crankshaft of the engine and is driven by an output torque of the engine to generate electricity, and a battery that can supply and receive electric power to and from the motor, and that automatically stops and restarts the engine, a controller that controls the engine and the motor, and that executes engine stop position control that, when performing the automatic stop, causes the motor to regenerate power to apply a braking torque to the crankshaft and stops the crankshaft at a predetermined target stop position; The controller acquiring an allowable charging power as the power allowable for charging the battery; prohibiting the automatic stop when the allowable charging power is smaller than a predetermined reference power amount; Prior to prohibiting the execution of the automatic stop, a time interval for prohibiting the execution of the automatic stop is set in advance. A control device for a hybrid vehicle.

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