JP7415361B2 - Engine power generation control device - Google Patents

Description

The present invention relates to a device for controlling a power generation device that is driven by an engine and generates electricity.

2. Description of the Related Art Conventionally, vehicles and the like have been provided with a power generation device that is driven by an engine to generate electricity, and the electric power generated by the power generation device is stored in a power storage device. Furthermore, a power generating device is also caused to generate power so that a predetermined amount of electricity is stored in the power storage device.

For example, Patent Document 1 discloses a control device for a hybrid vehicle that includes, as a drive source for running the vehicle, an engine, a motor generator driven by the engine to generate electricity, and a battery that stores electric power from the motor generator. When the amount of electricity stored in the power storage device falls below a predetermined amount while the engine is idling, the engine output is increased and the motor generator generates electricity to control the engine to a predetermined idle speed while charging the battery. A device is disclosed.

Japanese Patent Application Publication No. 2001-157306

In the device disclosed in Patent Document 1, the engine speed is maintained at a predetermined idle speed while the engine is idling, regardless of the amount of power generated by the motor generator. Therefore, if the power generation amount of the motor generator is increased in order to increase the amount of electricity stored in the power storage device when it is low, a large load will be applied to the engine while the engine rotational speed is low. Therefore, there is a problem in that engine rotational fluctuations increase and engine vibration becomes excessive.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an engine power generation control device that can suppress vibrations of the engine while ensuring the amount of power stored in the power storage device while the engine is idling. purpose.

In order to solve the above problems, the present invention provides a power generation device that is driven by an engine to generate electricity, a power storage device that can store electric power generated by the power generation device, and a control unit that controls the engine and the power generation device. and the control unit, when a specific condition including at least a condition that the amount of electricity stored in the electricity storage device is equal to or less than a preset first threshold value is satisfied during idling operation of the engine, the specific condition is satisfied. The power generation device is configured such that the rotation speed of the engine is higher than the rotation speed of the engine during idling operation and the resonance rotation speed at which the engine resonates, and the amount of electricity stored in the power storage device is increased. The present invention is characterized in that rapid charging control is executed to increase the amount of power generation compared to during idling operation when the specific condition is not satisfied (claim 1).

In this configuration, when the specific condition including at least the condition that the amount of electricity stored in the power storage device is equal to or less than the first threshold value is satisfied during idling operation of the engine, the amount of power generated by the power generation device is increased. In other words, when the amount of power stored in the power storage device is low, the amount of power generated by the power generation device is increased, so that it is possible to secure the amount of power stored. Furthermore, since the engine speed is increased when the amount of power generation increases, the combustion stability and rotation of the engine can be further stabilized, and fluctuations in engine rotation can be reduced while increasing the amount of power generation.

In addition, by being able to reduce engine rotational fluctuations, the engine rotational speed will match the resonant rotational speed when a specific condition does not hold, that is, if there is a rotational speed at which the engine resonates near the idle rotational speed that is achieved under normal conditions. This can prevent the engine from resonating during idling and causing excessive engine vibration.

In the configuration, preferably, the control unit determines that the specific condition is satisfied when the amount of power stored in the power storage device is equal to or less than the first threshold value and the amount of stored power is decreasing. ).

According to this configuration, when the amount of stored power of the power storage device is low and the amount of stored power is decreasing, and there is a risk that the amount of stored power of the power storage device may decrease to a very low amount, the quick charge control is performed. This will increase the amount of power generated by the power generation device. Therefore, it is possible to effectively suppress and ensure a reduction in the amount of electricity stored in the electricity storage device. Then, when the amount of stored power is below the first threshold value, the amount of stored power has not decreased, and it is not expected that the amount of stored power will decrease to a very low amount, the quick charging control is not implemented, so that the engine It is possible to reduce the chances of the rotation speed being changed.

In the configuration, preferably, the control unit starts the quick charging when the amount of electricity stored in the power storage device reaches or exceeds a second threshold set to a value higher than the first threshold after starting the quick charging control. The control is stopped (Claim 3).

According to this configuration, when the specific condition is satisfied, when the amount of electricity stored in the electricity storage device is low and the electricity storage device is discharging, the amount of electricity stored in the electricity storage device increases to an amount higher than when the specific condition is met. is enhanced. Therefore, even if discharging from the power storage device continues even after the quick charge control is stopped, it is possible to prevent the amount of power stored in the power storage device from becoming low early. This can reduce the chances of having to restart the quick charge control early after the quick charge control has been stopped.

In the configuration, preferably, during idling operation when the specific condition is not satisfied, when the amount of electricity stored in the electricity storage device is equal to or less than a predetermined third threshold that is larger than the first threshold, the control unit controls the Execute normal power generation control that causes the power generation device to generate power with a smaller amount of power generation than when executing the quick charge control, and when the amount of power stored in the power storage device is larger than the third threshold value, stop the power generation of the power generation device. Stop (Claim 4).

In this configuration, the power generation device generates power even when the specific condition is not satisfied and the amount of power stored in the power storage device is equal to or less than a predetermined third threshold value that is greater than the first threshold value. Therefore, the amount of power stored in the power storage device can be secured more reliably. However, when the specific condition is not satisfied, the amount of power stored in the power storage device is large or the amount of discharge from the power storage device is small, and the amount of power stored in the power storage device is likely to be maintained at a relatively high amount. In contrast, with this configuration, when the specific condition is not met and the amount of electricity stored in the power storage device is below the third threshold, the amount of power generated by the power generation device is lower than when the specific condition is met (during quick charge control). be destroyed. Therefore, while ensuring the amount of power stored in the power storage device, it is possible to prevent this from becoming excessively high. Furthermore, when the amount of power stored in the power storage device is larger than the third threshold value, the power generation of the power generation device is stopped, so that it is possible to secure the amount of power stored in the power storage device and more reliably prevent the amount of power from becoming excessively high.

In the configuration, preferably, after the start of the quick charging control, when the amount of electricity stored in the power storage device becomes equal to or higher than a second threshold set to a value higher than the first threshold, the control unit starts the quick charging. The control is stopped, and the second threshold is set to a value larger than the third threshold (claim 5).

According to this configuration, even if the amount of discharge from the power storage device is still large after the quick charge control is stopped, it is possible to prevent the amount of power stored in the power storage device from becoming low early. This can reduce the chances of having to restart the quick charge control early after the quick charge control has been stopped.

In the configuration, preferably, the control unit causes the power generation device to generate power so that the amount of power generated by the power generation device is maintained at a preset reference amount of power generation during execution of the quick charge control. Item 6).

According to this configuration, it is possible to reduce the amount of variation in the load applied to the engine from the power generation device during execution of the quick charge control, and it is possible to reduce the variation in the rotation of the engine due to the variation in the load.

In the configuration, preferably, at the start of the quick charging control, the control unit causes the power generation device to generate power and reduces the output of the engine so that the amount of power generation gradually increases toward the amount of power generation for quick charging. Increase gradually (Claim 7).

According to this configuration, it is possible to prevent a sudden increase in the load applied to the engine from the power generation device, and to reduce engine rotational fluctuations.

In the configuration, preferably, at the start of the quick charging control, the control unit causes the power generation device to generate power and reduces the output of the engine so that the amount of power generation gradually increases toward the amount of power generation for quick charging. Increase gradually (Claim 8).

According to this configuration, it is possible to prevent a sudden decrease in the load applied to the engine from the power generation device, and to reduce engine rotational fluctuations.

As described above, during idling operation of the engine, vibrations of the engine can be suppressed while ensuring the amount of power stored in the power storage device.

1 is a diagram schematically showing the configuration of a vehicle equipped with a power generation control device according to an embodiment of the present invention. FIG. 2 is a block diagram showing a control system of the vehicle. It is a flowchart showing the flow of control during idling operation. 5 is a time chart showing changes in each parameter over time when control according to an embodiment of the present invention is executed.

(1) Overall configuration of vehicle FIG. 1 is a diagram schematically showing the configuration of a vehicle in which a power generation control device 101 is mounted.

Vehicle 1 is, for example, a four-wheeled vehicle. Engine 2 is provided in the engine room of vehicle 1. The driving force of the engine 2 is transmitted from the crankshaft 2a to the wheels 1a via a transmission, a final reduction gear, a drive shaft, etc., and causes the vehicle 1 to travel.

The vehicle 1 is equipped with an engine 2 as a driving source for the vehicle, a starter 3, a motor generator 4, a Li battery (lithium battery) 9, a DC-DC converter 10, a lead battery 12, and various electrical devices. The motor generator 4 is a so-called ISG (Integrated Starter-Generator) that has a function as an electric motor and a function as a generator, and is hereinafter referred to as ISG4. The Li battery 9 corresponds to a "power storage device" in the claims, and the ISG 4 corresponds to a "power generation device" in the claims.

The engine 2 is formed with a cylinder 2c. In the example of FIG. 1, the engine 2 is an in-line four-cylinder engine, and includes four cylinders 2c arranged in a row. In this embodiment, the engine 2 is an engine driven by fuel including gasoline. Further, the engine 2 is configured such that the air-fuel mixture is partially compressed and self-ignited in each cylinder 2c in at least a part of the engine operating range (for example, in a low engine speed range), and the air-fuel mixture in each cylinder 2c is The geometric compression ratio is relatively high so that compression autoignition combustion is achieved. Partial compression self-ignition combustion refers to the air-fuel mixture that is ignited by a spark plug 31 (described later) and forcibly burns a part of the air-fuel mixture through flame propagation, and then the air-fuel mixture becomes hot and pressurized through this combustion. This is a type of combustion in which the remainder of the fuel is combusted by self-ignition.

The engine 2 includes an injector 30 (see FIG. 2) that injects fuel into each cylinder 2c, and a spark plug 31 (see FIG. 2) that ignites the mixture (air and fuel mixture) in each cylinder 2c. We are prepared. One injector 30 and one spark plug 31 are provided for each cylinder 2c. Further, an intake passage for introducing intake air into the engine 2 is provided with a throttle valve 32 (see FIG. 2) that opens and closes the intake passage.

The Li battery 9 is electrically connected to electrical equipment driven at high voltage (hereinafter referred to as high voltage equipment) via a high voltage line L1, and a high voltage circuit 14 is formed by these. The ISG 4 is included in the high voltage equipment and is connected to the Li battery 9 via the high voltage line L1. Note that in a vehicle equipped with a PTC heater for heating the interior of the vehicle 1 or a catalyst heater for heating a catalyst for purifying exhaust gas, these heaters are also connected to the Li battery 9 via the high voltage line L1.

The ISG 4 is connected to the crankshaft 2a of the engine 2 via a belt 4a. When operating as a generator, the ISG 4 generates electricity by rotating a rotor that rotates in a magnetic field in conjunction with the crankshaft 2a of the engine 2 via the belt 4a. The ISG 4 is capable of adjusting the generated voltage, that is, the amount of generated electricity, in accordance with an increase or decrease in the current supplied to the field coil that generates the magnetic field. The electric power generated by the ISG 4 is converted into direct current, outputted to the high voltage line L1, and stored in the Li battery 9 via the high voltage line L1. In this embodiment, the ISG 4 is controlled to operate as a generator when the vehicle is decelerated, and converts the rotational energy of the engine 2 into electricity. In other words, the ISG 4 is configured to perform so-called deceleration regenerative power generation.

When operating as an electric motor, the ISG 4 is rotationally driven by receiving power from the Li battery 9, transmits driving force to the crankshaft 2a of the engine 2 via the belt 4a, and provides driving force to the engine 2. do.

The vehicle 1 is configured to be able to automatically stop the engine 2, and when the engine 2 is restarted after the engine 2 is automatically stopped, the ISG 4 operates as an electric motor to forcibly drive the engine 2 to rotate. Specifically, the vehicle 1 is provided with a start/stop switch SW1 (see FIG. 2) that can be operated by a passenger to start and stop the engine 2. The engine 2 is started and stopped by operating the start/stop switch SW1, but even if the start/stop switch SW1 is not operated, the vehicle speed is below a predetermined value and the brake pedal 1b is depressed. When the conditions are met, such as when the engine is running, the driving of the engine 2 is automatically stopped. After this automatic stop, if the condition that the accelerator pedal (not shown) has been depressed or a predetermined automatic stop prohibition condition is satisfied, the engine 2 will be restarted automatically. When the engine 2 is automatically restarted, the ISG 4 is driven as an electric motor to forcibly rotate the engine 2. Note that automatic stop prohibition conditions include a case where the SOC of the Li battery 9 drops too much, a case where there is a request to drive the air conditioner, and the like.

Further, the ISG 4 operates as an electric motor to provide driving force to the engine 2 when the engine load is low. That is, in this embodiment, the ISG 4 is also configured to perform so-called torque assist.

The ISG 4 is equipped with an ISG controller 51 for controlling it. The ISG controller 51 has an inverter function, and when the ISG 4 functions as a generator, converts the alternating current generated by the ISG 4 into a DC current, and when the ISG 4 functions as a motor, converts it into a Li battery 9. Converts the direct current from the converter into alternating current and supplies it to ISG4. Further, the ISG controller 51 increases/decreases the current supplied to the field coil as described above, thereby increasing/decreasing the power generation amount of the ISG 4 and the driving force of the ISG 4. The ISG controller 51 has a microcomputer including a microprocessor, and the above-mentioned current control and the like are performed by the microcomputer.

The Li battery 9 is a battery that contains lithium in its positive electrode and is charged and discharged by movement of lithium ions between the positive electrode and the negative electrode.

The lead battery 12 is electrically connected via a low voltage line L2 to a low voltage electrical device 13 (hereinafter referred to as low voltage device) that is driven at a relatively low voltage, and a low voltage circuit 15 is formed by these. ing. The lead battery 12 includes, for example, six cells connected in series. The low voltage equipment 13 includes a starter 3 that rotates the engine when a start/stop switch SW1 (described later) is operated while the engine is stopped. In addition to the starter 3, the vehicle 1 is provided with low-voltage devices 13 such as an electric power steering mechanism (EAPS), an electric brake, an air conditioner, an audio device, and various lighting devices.

The DC-DC converter 10 is a device for stepping down the voltage of power supplied from the high voltage line L1 to the low voltage line L2. The output power from the Li battery 9 and the power generated by the ISG 4 are reduced in voltage by the DC-DC converter 10 and supplied to the low voltage equipment 13. Further, the surplus of the power generated by the ISG 4 is supplied to the lead battery 12, and the lead battery 12 is charged.

(2) Control System FIG. 2 is a block diagram schematically showing the control system of the vehicle 1. The PCM 100 shown in FIG. 2 is a microprocessor for controlling the engine in an integrated manner, and is composed of a well-known CPU, ROM, RAM, and the like.

Detection information from various sensors and operation signals from various switches are input to the PCM 100. Specifically, the vehicle 1 includes an accelerator sensor SN1 that detects the opening degree of the accelerator pedal provided in the vehicle 1, and a brake sensor SN2 that detects the amount of depression of the brake pedal 1b provided in the vehicle 1. , a vehicle speed sensor SN3 that detects the vehicle speed, a current sensor SN4 that detects the current and voltage flowing through the Li battery 9 (flowing between the Li battery 9 and the high voltage line L1), a voltage sensor SN5, and a voltage sensor SN5 that detects the engine rotation speed. A crank angle sensor SN6, a start/stop switch SW1 for a passenger to start and stop the engine, and the like are provided. Signals are input to the PCM 100 from these sensors SN1 to SN6 and the start/stop switch SW1. The PCM 100 is also connected to the injector 30, spark plug 31, ISG controller 51, starter 3 (controller that controls the starter), etc., and performs various judgments and calculations based on input information from each sensor and switch. It issues instructions to each of these parts while executing them. This PCM 100 corresponds to a "control unit" in the claims.

(3) Control during idling operation Control performed by the PCM 100 during idling operation (when the engine is idling) will be explained using FIG. 3.

In step S1, the PCM 100 reads the detection values of each sensor.

Next, in step S2, the PCM 100 calculates the amount of electricity stored in the Li battery 9. Here, the SOC (State of Charge: remaining capacity) of the Li battery 9 is calculated, and the ratio of the current amount of electricity stored in the Li battery 9 to the amount of electricity stored when the Li battery 9 is 100% charged is calculated. PCM 100 calculates the SOC of Li battery 9 from the detected values of current sensor SN4 and voltage sensor SN5.

Next, in step S3, the PCM 100 determines whether or not the engine is idling, that is, whether the engine is idling. The PCM 100 makes this determination based on detected values from the vehicle speed sensor SN3, crank angle sensor SN6, accelerator sensor SN1, and the like. For example, when the accelerator opening detected by the accelerator sensor SN1 is 0, the vehicle speed detected by the vehicle speed sensor SN3, and the engine rotation speed detected by the crank angle sensor SN6 are each below a predetermined value, idling is being performed. It is determined that

If the determination in step S3 is NO and it is determined that the vehicle is not idling, the process proceeds to step S4, and the PCM 100 executes control during running. The details of the control of ISG4 and the engine during non-idling operation will be omitted, but as mentioned above, the PCM 100 operates ISG4 as a generator to perform deceleration regenerative power generation while the vehicle 1 is decelerating, or activates ISG4. It can be operated as a machine to perform torque assist.

On the other hand, when the determination in step S3 is YES and it is determined that the vehicle is idling, the process advances to step S5.

In step S5, the PCM 100 determines whether the specific conditions that the SOC of the Li battery 9 is less than or equal to the quick charge start determination amount and that the SOC of the Li battery 9 is decreasing are satisfied. Specifically, the PCM 100 compares the SOC calculated in step S2 with the quick charge start determination amount, calculates the amount of change in SOC per unit time, and determines that this amount of change is negative and the amount of change is the same. When the absolute value is greater than or equal to a preset determination change amount, it is determined that the specific condition is satisfied. The quick charge start determination amount and the determination change amount are set in advance and stored in the PCM 100. For example, the quick charge start determination amount is set to about 35%, and the determination change amount is set to 0. The quick charging start determination amount corresponds to the "first threshold" in the claims.

When the determination in step S5 is NO and it is determined that the above-mentioned specific condition is not satisfied, that is, when the SOC of the Li battery 9 is larger than the rapid charging start determination amount, or when the SOC of the Li battery 9 is rapidly If the SOC of the Li battery 9 is not decreasing, although it is less than the charging start determination amount, the PCM 100 proceeds to step S6.

In step S6, the PCM 100 determines whether the SOC of the Li battery 9 is less than or equal to the normal charging start determination amount. The normal charge start determination amount is set to a larger value than the quick charge start determination amount. The normal charging start determination amount is set in advance and stored in the PCM 100. Normally, the charging start determination amount is set to a value of about 40 to 45%. The normal charging start determination amount corresponds to the "third threshold" in the claims.

If the determination in step S6 is NO and the SOC of the Li battery 9 is larger than the normal charge start determination amount, the process proceeds to step S7. In step S7, the PCM 100 issues a command to the ISG controller 51 to stop driving the ISG 4 and stop the power generation by the ISG 4. Further, the PCM 100 controls the engine so that the engine speed becomes the basic idle speed. The basic idle rotation speed is set near the lowest rotation speed at which the engine can independently rotate under no-load conditions. The basic idle rotation speed is, for example, about 650 rpm.

Specifically, the amount of intake air (the amount of intake air introduced into each cylinder 2c) and the amount of fuel (the amount of air supplied from the injector 30 to each cylinder 2c) when the engine is in an unloaded state and its rotational speed becomes the basic idle rotational speed. A basic idle intake air amount and a basic fuel amount, which are the amount of fuel to be used, are set in advance and stored in the PCM 100. In step S7, the PCM 100 controls the throttle valve 32 and the injector 30 so that these basic idle intake air amount and basic fuel amount are achieved. Through this control, the engine speed is set to the basic idle speed. In the following, the time when step S7 is performed will be appropriately referred to as normal idle time.

After step S7, the process ends (returns to step S1).

On the other hand, if the determination in step S6 is YES and the SOC of the Li battery 9 is equal to or less than the normal charging start determination amount, the process proceeds to step S8. In step S8, PCM 100 performs normal charging control.

Normal charging control is control that causes the ISG 4 to generate electricity while maintaining the engine speed at the basic idle speed.

In step S8, the PCM 100 drives the ISG 4 as a generator to cause the ISG 4 to generate electricity. At this time, the PCM 100 issues a command to the ISG controller 51 to cause the ISG 4 to generate power so that the amount of power generated by the ISG 4 becomes a preset normal power generation amount. In step S8, the PCM 100 controls the engine so that the engine output becomes a normal charging output higher than that during normal idling. The normal charging output is an amount obtained by adding the engine output corresponding to the energized power generation amount to the engine output during normal idling, and in step S8, the engine output is increased by the amount corresponding to the normal power generation amount with respect to the normal idling. While increasing the power generation amount, the power generation amount of ISG4 is made to be the normal power generation amount. In other words, the PCM 100 increases the engine output compared to normal idling and allows ISG4 to absorb this increase, allowing ISG4 to generate the normal amount of power while increasing the engine speed to the normal idling speed. Maintain the same basic idle speed. For example, the intake air amount and fuel amount required to make the engine output the normal charging output are set in advance and stored in the PCM 100, and the PCM 100 determines that the intake air amount and fuel amount are set to these stored amounts. The throttle valve 32 and the injector 30 are controlled so that. The normal power generation amount is constant regardless of the engine operating state and the SOC of the Li battery 9, and the power generation amount of the ISG 4 is maintained constant during normal charging control.

Normal charging control is performed when the determination in step S3 is NO and engine idling has ended, the determination in step S5 is YES and the above-mentioned specific conditions are satisfied, or the determination in step S6 is If the answer is NO and the SOC of the Li battery 9 becomes larger than the normal charging start determination amount, the process is terminated.

Returning to step S5, if the determination in step S5 is YES and it is determined that the above-mentioned specific conditions are satisfied (the SOC of the Li battery 9 is equal to or less than the quick charge start determination amount, and the SOC of the Li battery 9 is If it is determined that the power is decreasing), the process advances to step S9.

In step S9, PCM 100 executes quick charging control.

The quick charge control is a control in which the engine speed is set to a quick charging idle speed higher than the basic idle speed, the ISG 4 is caused to generate power, and the amount of power generated is made larger than during normal charge control.

In step S9, the PCM 100 issues a command to the ISG controller 51 to drive the ISG 4 as a generator to cause the ISG 4 to generate electricity. At this time, the PCM 100 causes the ISG 4 to generate power so that the power generation amount of the ISG 4 is a preset power generation amount for quick charging, which is larger than the normal power generation amount. Furthermore, in step S9, the PCM 100 controls the engine so that the engine output becomes a quick charging output higher than the normal charging output. As described above, in step S9, the amount of power generated by ISG4 is lower than in step S8 and step S7, which are executed when the engine is idling and the specific conditions are not satisfied, that is, when the quick charge control is not executed. and the engine power is increased.

The output for quick charging is the sum of the engine output corresponding to the amount of power generated for quick charging and the engine output required to bring the engine speed to the idle speed for quick charging. In other words, the PCM100 increases the engine output compared to normal idling, and by having ISG4 absorb a part of this increase, ISG4 generates the power for quick charging, and the engine output increases. The engine speed is made higher than the basic idle speed by the remainder of the minute. For example, the intake air amount and fuel amount required to make the engine output the output for quick charging are set in advance and stored in the PCM 100, and the PCM 100 determines that the intake air amount and fuel amount are the same as these stored amounts. The throttle valve 32 and the injector 30 are controlled so that.

The power generation amount for quick charge and the output for quick charge are constant regardless of the operating state of the engine and the SOC of the Li battery 9, and the power generation amount of the ISG 4 is basically maintained constant during the quick charge control. However, at the start of quick charge control, the PCM 100 does not suddenly increase the engine output and the power generation amount of ISG4 to the power generation amount for quick charge and the output for quick charge, but instead Increase gradually towards output. Also, at the end of the quick charge control, the PCM 100 gradually reduces the engine output and the power generation amount of the ISG 4 from the quick charge power generation amount and the quick charge output.

After step S9, the process advances to step S10. In step S10, the PCM 100 determines whether the SOC of the Li battery 9 is greater than or equal to a preset rapid charge termination determination amount. The quick charge end determination amount is set to a higher value than the quick charge start determination amount and the normal charge start determination amount. The quick charge end determination amount is set in advance and stored in the PCM 100. If the determination in step S10 is NO and the SOC of the Li battery 9 is less than the quick charge termination determination amount, the process returns to step S9 and the quick charge control is continued. On the other hand, if the determination in step S10 is YES and the SOC of the Li battery 9 becomes equal to or greater than the quick charge end determination amount, the process proceeds to step S11, and the PCM 100 ends the quick charge control. After step S11, the process ends (returns to step S1). The quick charging end determination amount corresponds to a "second threshold" in the claims.

In this way, once this control is started, the quick charge control is continued until the SOC of the Li battery 9 becomes higher than the SOC at the start of the control. Note that the quick charging control is terminated when the engine stops driving or when the engine operating state exits from idling.

(4) Effects, etc. FIG. 4 is a time chart schematically showing an example of changes over time in each parameter when the above control is implemented. FIG. 4 shows, from top to bottom, the SOC of the Li battery 9, the current consumed by the high voltage circuit 14, that is, the discharge current from the Li battery 9, the engine output, the amount of power generated by the ISG 4, and the engine speed. Shows a graph. Hereinafter, the current consumed by the high voltage circuit 14 will be simply referred to as consumption current. Note that the engine is in idle operation until time t6 in FIG. 4.

Until time t1, the engine is in idle operation, the current consumption is 0, and the SOC of the Li battery 9 is higher than the normal charging start determination amount X1. From this point on, until time t1, the engine speed is set to the basic idle speed N1, and the engine output is set to the normal idle output E1, which is the output corresponding to this. Furthermore, power generation at ISG4 is stopped.

On the other hand, when the current consumption increases at time t1, the SOC of the Li battery 9 decreases. At time t2, when the SOC of the Li battery 9 becomes equal to or less than the normal charging start determination amount X1, normal charging control is started. As a result, power generation in ISG4 is started at time t2. Further, the engine output is increased to the normal charging output E2, and the power generation amount of the ISG 4 is set to the normal power generation amount W1, while the engine speed is maintained at the basic idle speed N1.

Here, the load applied to the engine increases as the ISG 4 generates electricity, but since the amount of electricity generated by the ISG 4 is small, engine rotation fluctuations can be suppressed to a small level.

With the start of normal charging control, a decrease in the SOC of Li battery 9 is suppressed. However, when the current consumption increases rapidly at time t3, the SOC of the Li battery 9 decreases significantly again. At this time, if normal power generation control is continued, the SOC of the Li battery 9 will drop to a very small value as shown by the chain line in FIG. 4 because the amount of power generated by the ISG 4 is small. If the engine is stopped with the SOC reduced to a very small value in this way, the SOC of the Li battery 9 will be maintained at this small value. In the Li battery 9, deterioration is accelerated when its SOC becomes equal to or less than a predetermined deterioration acceleration amount Z. Therefore, if normal power generation control is continued as described above, the SOC of the Li battery 9 will fall below the deterioration acceleration amount Z, and deterioration will be accelerated. Furthermore, if the SOC of the Li battery 9 is low, there is a possibility that the ISG 4 may not be able to properly restart the engine, or that various high-voltage devices may not be appropriately driven when the engine is started.

In contrast, in this embodiment, when the SOC of the Li battery 9 becomes equal to or less than the quick charge start determination amount X2 at time t4 after time t3, the quick charge control is executed and the power generation amount of the ISG 4 is increased. Ru. This prevents the SOC of the Li battery 9 from decreasing, and further increases the SOC of the Li battery 9. Specifically, at time t4, the power generation amount of ISG4 is gradually increased toward the power generation amount for quick charging W2, and the engine output is gradually increased toward the output for quick charging E3. After time t4, unlike before, the engine speed is gradually increased toward the rapid charging idle speed N2. When the power generation amount of ISG4 reaches the power generation amount W2 for quick charging, the power generation amount of ISG4 is maintained at this level, and when the engine output reaches the output E3 for quick charging, the engine output is maintained at this level.

At time t5, when the SOC of the Li battery 9 becomes equal to or higher than the quick charge end determination amount Y1, the quick charge control is stopped. As a result, the amount of power generated by ISG4 is gradually reduced toward zero. Further, the engine output is gradually reduced toward the normal idle output E1.

The SOC of the Li battery 9 decreases again as the power generation in the ISG 4 is stopped while the current consumption is high, but at time t5, the SOC of the Li battery 9 is higher than the normal charge start determination amount X1 for rapid charging. By increasing the termination determination amount Y1, the SOC of the Li battery 9 is maintained at a high value. As a result, as in the example of FIG. 4, even if the engine is stopped at time t6 after time t5, the SOC of the Li battery 9 can be made higher than the deterioration acceleration amount Z. As described above, in this embodiment, by executing the quick charging control, deterioration of the Li battery 9 is suppressed, and the restart of the engine and appropriate driving of various high-voltage devices at the time of starting the engine are realized. .

Here, after time t4, the idea is to increase the engine output and the amount of power generated by ISG4 while maintaining the engine speed at the basic idle speed, in the same way as up to time t4, that is, similarly to normal charging control. It will be done. However, if the engine speed is maintained at the basic idle speed and the engine output and the amount of power generated by ISG4 are increased to high values such as the output for quick charging and the amount of power generated for quick charging, the engine speed will be low. In other words, in a state where the combustion stability of the engine is low and rotation is likely to become unstable, a very high load is applied to the engine, resulting in increased engine rotational fluctuations. Furthermore, when the engine resonance frequency N10 is near the basic idle rotation speed N1, the engine rotation speed and the resonance frequency N10 match when the engine rotation changes, and the engine rotation changes as shown by the broken line in FIG. may become very large. Therefore, if the engine output and the amount of power generated by ISG4 are increased to the output for quick charging and the amount of power generated for quick charging while maintaining the engine speed at the basic idle speed, engine vibration may become excessively large. . On the other hand, in the present embodiment, when the quick charging control is executed after time t4, the engine rotation speed is also increased while increasing the engine output and the amount of power generated by ISG4. Therefore, fluctuations in engine rotation and, in turn, increases in engine vibration are suppressed.

As described above, in this embodiment, the specific condition that the SOC of the Li battery 9 is equal to or lower than the quick charge start determination amount (X2) and that this SOC is decreasing is satisfied during idling operation of the engine. When the SOC of the Li battery 9 is low and there is a risk that the SOC of the Li battery 9 may drop to a very low value, quick charging control is executed to determine if the specific conditions are not met. In other words, the engine output is made larger than during normal idling operation and normal charge control to increase the amount of power generated by ISG4, and the engine rotational speed is increased. Therefore, the SOC of the Li battery 9 can be ensured, and the engine can be restarted and various high-voltage devices can be appropriately driven when the engine is started. Moreover, early deterioration of the Li battery 9 can be prevented. Furthermore, it is possible to increase the amount of power generated by the ISG 4 and increase the SOC of the Li battery 9 at an early stage, while suppressing fluctuations in engine rotation and thus engine vibration. Particularly in an engine in which the resonance rotation speed (N10) of the engine exists near the basic idle rotation speed (N1), it is possible to prevent the engine from significantly vibrating due to engine resonance.

Furthermore, in the present embodiment, the quick charge control is ended when the SOC of the Li battery 9 becomes equal to or higher than the quick charge end determination amount (Y1), which is higher than the quick charge start determination amount (X2). Therefore, even if the Li battery 9 continues to be discharged after the quick charge control ends, the SOC of the Li battery 9 can be ensured.

Further, in this embodiment, even when the SOC of the Li battery 9 is equal to or less than the normal charge start determination amount (X1), normal power generation control is executed and power generation by the ISG 4 is performed. Therefore, the SOC of the Li battery 9 can be ensured more reliably. Here, when the specific condition is not satisfied, it is unlikely that the SOC of the Li battery 9 will drop to a very low value. On the other hand, in normal power generation control that is executed when specific conditions are not satisfied, the power generation amount of ISG4 is set to the power generation amount for normal charging (W2) which is lower than the power generation amount for quick charging (W2), which is the power generation amount during quick charge control. W1). Therefore, while ensuring the SOC of the Li battery 9, the energy required to generate electricity from the ISG 4 can be reduced. Furthermore, it is possible to prevent the SOC of the Li battery 9 from becoming excessively high. Note that if the SOC of the Li battery 9 becomes excessively high, deceleration regenerative power generation cannot be performed sufficiently.

Further, in this embodiment, when the SOC of the Li battery 9 is larger than the normal charge start determination amount (X1), power generation by the ISG 4 is stopped. Therefore, while ensuring the SOC of the Li battery 9, it is possible to reduce the power generation opportunities of the ISG 4, thereby reducing the energy required for the ISG 4 to generate power, and it is possible to prevent the SOC of the Li battery 9 from becoming excessively high.

Furthermore, in the present embodiment, during execution of the quick charge control, the ISG 4 is controlled so that the power generation amount of the Li battery 9 is maintained at the quick charge power generation amount (W2). Therefore, during the quick charge control, fluctuations in the load applied to the engine from the ISG 4 can be reduced, and engine rotational fluctuations can be more reliably reduced.

Furthermore, in the present embodiment, at the start of quick charge control, ISG4 is controlled so that the amount of power generation gradually increases toward the amount of power generation for quick charge. Therefore, a sudden increase in the load applied to the engine from the ISG 4 can be prevented, and engine rotational fluctuations can be reduced more reliably.

Furthermore, by controlling ISG4 so that the amount of power generation is gradually increased from the amount of power generation for quick charging at the end of quick charge control, a sudden decrease in the load applied to the engine from ISG4 can be prevented, and engine rotation fluctuations can be prevented. can definitely be made smaller.

(5) Modification example
In the embodiment, in step S5, the PCM 100 determines whether the conditions that the SOC of the Li battery 9 is equal to or less than the quick charge start determination amount and that the SOC of the Li battery 9 is decreasing are satisfied; A case has been described in which, when this determination is YES, the process proceeds to step S9 and the PCM 100 executes the quick charging control. In other words, when the SOC of the Li battery 9 is less than or equal to the quick charge start determination amount and the SOC of the Li battery 9 is decreasing, the PCM 100 determines that the specific condition that is the execution condition for the quick charge control is satisfied. I explained the case. However, the specific condition that is the execution condition for the quick charge control may include at least the condition that the SOC of the Li battery 9 is less than or equal to the quick charge start determination amount. If it is less than or equal to the determination amount, it may be determined that the specific condition is satisfied regardless of whether or not the SOC is decreasing. In this example as well, when the SOC of the Li battery 9 is less than the quick charge start determination amount and not sufficiently high, the quick charge control is performed, so that the SOC of the Li battery 9 is By ensuring an SOC of 9, deterioration of the Li battery 9 and proper operation of electrical equipment can be realized. However, when the SOC of the Li battery 9 is decreasing, there is a high possibility that the SOC of the Li battery 9 will subsequently decrease to a very low value, and when the SOC of the Li battery 9 is not decreasing, the above possibility is low. Therefore, if the quick charge control is executed only when the SOC of the Li battery 9 is below the quick charge start determination amount and the SOC of the Li battery 9 is decreasing, a significant decrease in the SOC of the Li battery 9 can be effectively prevented. While avoiding this problem, it is possible to further stabilize the engine speed by reducing the opportunity to implement quick charge control and the opportunity to change the engine speed during idling.

Further, in the embodiment described above, a case has been described in which the Li battery 9 is used as the power storage device that stores the power generated by the ISG 4, but the power storage device is not limited to the Li battery 9. For example, a lead battery or a capacitor may be used as the power storage device.

Further, in the above embodiment, a case has been described in which the ISG 4 having a function as an electric motor is used as a power generation device driven by an engine to generate electricity, but this power generation device is not limited to the ISG 4. For example, as the power generation device, one having only a power generation function may be used.

2 Engine 4 ISG (power generator)
9 Li battery (power storage device)
100 PCM (control unit)

Claims (8)

A power generation device that is driven by an engine to generate electricity;
a power storage device capable of storing power generated by the power generation device;
comprising a control unit that controls the engine and the power generation device,
The control unit includes:
If a specific condition, including at least a condition that the amount of electricity stored in the power storage device is equal to or less than a preset first threshold value, is satisfied during idling operation of the engine, then the engine during idling operation where the specific condition is not satisfied is satisfied. The specific condition is established such that the power generation amount of the power generation device is set such that the rotation speed of the engine is higher than a resonance rotation speed that is a rotation speed at which the engine resonates, and the amount of electricity stored in the power storage device is increased. A power generation control device for an engine, characterized in that the engine power generation control device executes quick charging control to increase charging speed more than during idling operation. The engine power generation control device according to claim 1,
An engine power generation control device, wherein the control unit determines that the specific condition is satisfied when the amount of power stored in the power storage device is equal to or less than the first threshold value and the amount of stored power is decreasing. . The engine power generation control device according to claim 1 or 2,
The control unit is characterized in that, after the start of the quick charge control, when the amount of electricity stored in the power storage device reaches or exceeds a second threshold set to a value higher than the first threshold, the control unit stops the quick charge control. Power generation control device for the engine. The engine power generation control device according to claim 1 or 2,
During idling operation when the specific condition is not met, when the amount of electricity stored in the electricity storage device is equal to or less than a predetermined third threshold that is greater than the first threshold, the control unit controls the control unit to A normal power generation control is executed to cause the power generation device to generate power with a smaller amount of power generation, and when the amount of power stored in the power storage device is larger than the third threshold, power generation of the power generation device is stopped. A power generation control device for the engine. The engine power generation control device according to claim 4,
After the start of the quick charge control, the control unit stops the quick charge control when the amount of electricity stored in the power storage device reaches or exceeds a second threshold set to a value higher than the first threshold;
The engine power generation control device, wherein the second threshold value is set to a value larger than the third threshold value. The engine power generation control device according to any one of claims 1 to 5,
The control unit causes the power generation device to generate power so that the power generation amount of the power generation device is increased to a preset power generation amount for quick charging and then maintained at this level when executing the quick charge control. An engine power generation control device characterized by: The engine power generation control device according to claim 6,
The control unit is characterized in that, at the start of the quick charging control, the control unit causes the power generation device to generate power and gradually increases the output of the engine so that the amount of power generation gradually increases toward the amount of power generation for quick charging. A power generation control device for the engine. The engine power generation control device according to claim 6 or 7,
An engine characterized in that, when the quick charging control ends, the control unit causes the power generation device to generate power and gradually reduces the output of the engine so that the amount of power generation gradually decreases from the amount of power generation for quick charging. power generation control device.