JP6776974B2 - Vehicle control unit - Google Patents

Description

The present invention is stopped by, for example, rotating the internal combustion engine with a cranking torque that is capable of traveling using at least one output of the internal combustion engine and the electric motor and using at least a part of the output of the electric motor. The present invention relates to a technical field of a vehicle control device for controlling a vehicle capable of starting an internal combustion engine.

Vehicles equipped with an internal combustion engine and an electric motor (so-called hybrid vehicles) are known. The hybrid vehicle has two modes of travel: EV (Electric Vehicle) mode in which the internal combustion engine is stopped and the output of the electric motor is used, and at least one output of the internal combustion engine and the electric motor is driven. It is possible to switch between the HV (Hybrid Vehicle) mode in which the vehicle is used and traveled. When the traveling mode is switched from the EV mode to the HV mode, the stopped internal combustion engine is started. In this case, the internal combustion engine is started by rotating (that is, cranking) the engine shaft of the internal combustion engine with a cranking torque using at least a part of the output of the electric motor.

Patent Document 1 describes a vehicle control device that controls the start of an internal combustion engine with a cranking torque using the output of such an electric motor. Specifically, the vehicle control device described in Patent Document 1 controls the start of an internal combustion engine that is performed while the vehicle accelerates at a relatively large acceleration due to a large depression of the accelerator pedal. At this time, since a part of the output of the electric motor is used as cranking torque, the other part of the output of the electric motor used as the driving force of the vehicle may decrease. As a result, the acceleration may drop as the internal combustion engine starts. In Patent Document 1, it is assumed that such a drop in acceleration occurs when the output of the electric motor (particularly, the output torque) reaches a limit value based on the electric power stored in the power storage device. Therefore, the vehicle control device described in Patent Document 1 has an output torque of the electric motor in response to an increase in the required torque of the electric motor in order to prevent a drop in acceleration due to the start of the internal combustion engine under such a situation. Is increased with a delay, and the delay width of the increase in the output torque is increased when the limit value (that is, the limit torque) is approached from the initial stage when the output torque is started to be increased. As a result, at the beginning of acceleration, the torque corresponding to the drive request is output from the electric motor, so that the intended acceleration feeling is obtained, and then the increasing gradient of the output torque gradually decreases so as not to be limited by the limiting torque. The feeling of acceleration does not drop.

In addition, Patent Document 2 is mentioned as a prior art document related to the present invention.

JP-A-2010-000870 Japanese Unexamined Patent Publication No. 2016-060379

However, even if the output torque of the electric motor is increased with a delay in response to the increase in the required torque of the electric motor, the output of the electric motor used as the driving force of the vehicle is as long as a part of the output of the electric motor is used as the cranking torque. There is still the possibility that some other parts will decrease. In particular, when a relatively large cranking torque is required to start the internal combustion engine relatively early, most of the output of the electric motor is used as the cranking torque, so that the driving force of the vehicle is used. It is relatively likely that the other part of the output of the motor used will be reduced. As a result, even if the output torque of the electric motor is delayed and increased with respect to the increase in the required torque as described in Patent Document 1, there is still a possibility that the acceleration feeling of the vehicle may be deteriorated. Rather, in the vehicle control device described in Patent Document 1, since the increase in the output torque of the electric motor is suppressed, not only the driving force required to realize the intended acceleration feeling cannot be secured, but also the internal combustion engine Even ensuring sufficient cranking torque for starting (especially relatively early starting) can be difficult.

Examples of the problems to be solved by the present invention include the above. The present invention provides a vehicle control device capable of appropriately realizing an intended acceleration feeling while appropriately securing the cranking torque required for starting the internal combustion engine when the internal combustion engine is started at the timing when the vehicle accelerates. That is the issue.

<1>
One aspect of the vehicle control device of the present invention is capable of traveling by using at least one output of an internal combustion engine and an electric motor as a driving force for traveling, and uses at least a part of the output of the electric motor. A vehicle control device that controls a vehicle capable of starting the internal combustion engine that is stopped by rotating the internal combustion engine with a ranking torque, and the traveling state of the vehicle is the amount of increase in the accelerator opening per unit time. When the internal combustion engine is started at the timing of transitioning from the first state where The start of the engine is started, the fluctuation of the driving force is suppressed from the start of the start of the internal combustion engine until a predetermined time elapses, and the predetermined time has elapsed since the start of the internal combustion engine is started. Later, the increase in the driving force is allowed.

According to one aspect of the vehicle control device of the present invention, the fluctuation (particularly, increase) of the driving force is suppressed from the start of starting the internal combustion engine until a predetermined time elapses, so that the fluctuation is relatively large. Cranking torque can be secured. As a result, the internal combustion engine can be started relatively early. On the other hand, since the fluctuation (particularly, decrease) of the driving force is suppressed, the vehicle can continue the steady running (or the acceleration up to that point can be maintained). Therefore, since the situation in which the acceleration decreases does not occur, the feeling of acceleration does not decrease.

After that, after a predetermined time has elapsed from the start of starting the internal combustion engine, the vehicle accelerates because the increase in the driving force is allowed. At this timing, since the rotation speed of the internal combustion engine is correspondingly increased, it is relatively likely that a relatively large cranking torque is not required to start the internal combustion engine. Alternatively, since the start of the internal combustion engine has already been completed, it is relatively likely that not only the cranking torque is not required but also the output of the internal combustion engine can be used as the driving force. As a result, the vehicle can accelerate at the intended acceleration after a predetermined time has elapsed from the start of the start of the internal combustion engine.

As a result, the vehicle control device can start the internal combustion engine so as to appropriately realize the intended acceleration feeling while appropriately securing the cranking torque required for starting the internal combustion engine at the timing when the vehicle accelerates. ..

<2>
In another aspect of the vehicle control device described above, the internal combustion engine is at the timing of transition from the third state in which the traveling state of the vehicle accelerates in a situation where the increase amount is less than the predetermined amount to the second state. The electric motor at the time when the traveling state transitions from the third state to the second state from the maximum value of the output of the electric motor that can be output by the power storage device using the electric power that can be supplied to the electric motor. The internal combustion engine is started with the cranking torque set to be smaller than the torque conversion value of the value obtained by subtracting the actual output of.

According to this aspect, if the internal combustion engine needs to be newly started while the vehicle is accelerating, the cranking torque is obtained by subtracting the actual output of the motor from the maximum output of the motor. It becomes smaller than the torque conversion value of the value to be obtained. As a result, even if a part of the output of the motor is used as the cranking torque, the actual output of the motor at the time of transition to the second state (that is, at least the first state) is used as the output of the motor used for the driving force. The minimum output required to maintain the running on the vehicle) can be secured. That is, fluctuations in the driving force are appropriately suppressed. As a result, deterioration of the acceleration feeling of the vehicle due to the start of the internal combustion engine performed while the vehicle is accelerating is appropriately suppressed.

FIG. 1 is a block diagram showing an example of the configuration of the vehicle of the present embodiment. FIG. 2 is a flowchart showing the flow of the starting operation. FIG. 3 is a flowchart showing the flow of the driving force suppressing operation. FIG. 4 is a flowchart showing the flow of the early start operation. FIG. 5 is a timing chart showing a specific example of the state of the vehicle in which the starting operation is performed. FIG. 6 is a flowchart showing a flow of a modified example of the starting operation. FIG. 7 is a flowchart showing a flow of a modified example of the early start operation. FIG. 8 is a timing chart showing a specific example of the state of the vehicle in which a modified example of the starting operation is performed.

Hereinafter, embodiments of the vehicle control device of the present invention will be described with reference to the drawings. In the following, the description will proceed using the vehicle 1 to which the embodiment of the vehicle control device of the present invention is applied.

(1) Configuration of Vehicle 1 First, the configuration of vehicle 1 of the present embodiment will be described with reference to FIG. Here, FIG. 1 is a block diagram showing an example of the configuration of the vehicle 1 of the present embodiment.

As shown in FIG. 1, the vehicle 1 includes an axle 11, wheels 12, an engine ENG which is a specific example of an "internal combustion engine", a motor generator MG which is a specific example of an "electric motor", and an inverter 400. , A battery 500, which is a specific example of a “power storage device”, and an ECU (Electronic Control Unit) 100, which is a specific example of a “vehicle control device”.

The axle 11 is a transmission shaft for transmitting at least a part of the outputs of the engine ENG and the motor generator MG to the wheels 12 as driving force. The wheels 12 are means for transmitting the driving force transmitted via the axle 11 to the road surface. In the following, unless otherwise specified, the "driving force" is the driving force of the vehicle 1 (that is, the driving force transmitted to the wheels 12 via the axle 11 to drive the vehicle 1). means.

The engine ENG is driven by burning fuel such as gasoline or light oil (in other words, it operates). The output of the engine ENG (hereinafter referred to as "engine output") is used as a driving force for the vehicle 1 to travel.

The motor generator MG is driven by using the electric power stored in the battery 500. The output of the motor generator MG (hereinafter referred to as "motor output") is used as a driving force for the vehicle 1 to travel. Further, at least a part of the motor output is used as a cranking torque TC for starting the stopped engine ENG.

The inverter 400 converts the DC power taken out from the battery 500 into AC power and supplies it to the motor generator MG. The battery 500 is a power supply source that supplies electric power for driving the motor generator MG to the motor generator MG.

The ECU 100 is an electronic control unit configured to be able to control the entire operation of the vehicle 1. The ECU 100 can switch the traveling mode of the vehicle 1 between the EV (Electric Vehicle) mode and the HV (Hybrid Vehicle) mode. The EV mode is a traveling mode in which the vehicle 1 travels by using the output of the motor generator MG after stopping the engine ENG. The HV mode is a traveling mode in which the vehicle 1 travels by driving the engine ENG (that is, without stopping) and using the output of at least one of the engine ENG and the motor generator MG.

When the traveling mode of the vehicle 1 is switched from the EV mode to the HV mode, the ECU 100 starts the stopped engine ENG. In order to start the engine ENG, the ECU 100 outputs the cranking torque TC to the engine ENG and controls the motor generator MG so as to rotate the engine shaft (in other words, the crankshaft) of the engine ENG.

(2) Starting operation performed by the ECU 100 Subsequently, a starting operation for starting the stopped engine ENG will be described with reference to FIG. FIG. 2 is a flowchart showing a flow of starting operation for starting the stopped engine ENG.

As shown in FIG. 2, the ECU 100 acquires the accelerator opening degree Ap from the accelerator opening degree sensor included in the vehicle 1 (step S1). In the following description, t means a variable that is incremented by 1 each time the accelerator opening Ap is acquired once. Therefore, in the following description, the accelerator opening Ap (t) means the latest accelerator opening Ap, and the accelerator opening Ap (t-1) means the previously acquired accelerator opening Ap. .. Further, the ECU 100 acquires the vehicle speed V from the vehicle speed sensor included in the vehicle 1 (step S1).

After that, the ECU 100 sets a target value of the driving force required for the vehicle 1 to travel (hereinafter, referred to as “target driving force”) based on the accelerator opening Ap (t) and the vehicle speed V acquired in step S1. Calculate (step S2). Since the existing operation can be used as the operation for calculating the target driving force based on the accelerator opening Ap (t) and the vehicle speed V, detailed description thereof will be omitted.

After that, the ECU 100 sets the driving force suppression counter C to 0, which is the initial value (step S3). The driving force suppression counter C is a variable indicating the length of the period during which the driving force suppression operation (step S7) described later is performed. The driving force suppressing operation is an operation for suppressing fluctuations (specifically, increase and decrease) of the driving force of the vehicle 1. As will be described in detail later, the driving force suppressing operation suppresses the deterioration of the acceleration feeling of the vehicle 1 due to the start of the stopped engine ENG while securing the cranking torque TC required for starting the engine ENG. It is done to do.

After that, the ECU 100 calculates the accelerator opening opening increase amount dAp (step S4). The accelerator opening degree increase amount dAp indicates the amount of increase in the accelerator opening degree Ap per unit time. The ECU 100 calculates the accelerator opening degree increase amount dAp (t) by subtracting the accelerator opening degree Ap (t-1) from the accelerator opening degree Ap (t).

After that, the ECU 100 determines whether or not the accelerator opening opening increase amount dAp (t) calculated in step S4 is equal to or greater than a predetermined threshold value α (however, α> 0) (step S5). Further, the ECU 100 determines whether or not the previously calculated accelerator opening degree increase amount dAp (t-1) is less than the predetermined threshold value α (step S5). The accelerator opening degree increase amount dAp (t-1) is a value obtained by subtracting the accelerator opening degree Ap (t-2) from the accelerator opening degree Ap (t-1).

The determination operation in step S5 is an operation for determining whether or not the accelerator opening opening increase amount dAp, which is smaller than the predetermined threshold value α, becomes equal to or more than the predetermined threshold value α. In the situation where the accelerator opening increase amount dAp, which was smaller than the predetermined threshold α, becomes equal to or higher than the predetermined threshold α, the driver who has not or has already depressed the accelerator pedal depresses the accelerator pedal relatively quickly (that is,). Corresponds to the situation (increased the speed of stepping on). Therefore, when the accelerator opening increase amount dAp, which is smaller than the predetermined threshold value α, becomes the predetermined threshold value α or more, the driver has stopped until then, is in steady running, or accelerates relatively slowly. It is presumed that he has an intention to accelerate the vehicle 1 that has been made to accelerate relatively rapidly. Therefore, in the determination operation of step S5 for determining whether or not the accelerator opening increase amount dAp, which is smaller than the predetermined threshold value α, becomes the predetermined threshold value α or more, the vehicle 1 that has not accelerated relatively rapidly is relative. It can be said that it is equivalent to the operation of determining whether or not it is necessary to accelerate rapidly. That is, the determination operation in step S5 is an operation for determining whether or not the vehicle 1 that has stopped, is running constantly, or is accelerating relatively slowly needs to accelerate relatively rapidly. It can be said that they are equivalent.

The predetermined threshold value α is a parameter set so that whether or not the traveling state of the vehicle 1 is in a sudden acceleration state can be specified from the accelerator opening opening increase amount dAp. The sudden acceleration state is a state in which the vehicle 1 needs to accelerate relatively rapidly as compared with the non-rapid acceleration state (specifically, the stopped state, the steady running state, and the slow acceleration state). In particular, the sudden acceleration state is preferably a state in which the vehicle 1 needs to accelerate after starting the engine ENG. The stopped state is a state in which the vehicle 1 is stopped. The steady running state is a state in which the vehicle 1 is running steadily. The slow acceleration state is a state in which the vehicle 1 needs to accelerate relatively slowly. In particular, the slow acceleration state is preferably a state in which the vehicle 1 can accelerate without starting the engine ENG. The determination in step S5 based on such a predetermined threshold value α is substantially equivalent to the operation of determining whether or not the traveling state of the vehicle 1 transitions from the non-rapid acceleration state to the sudden acceleration state.

The predetermined threshold value α may be a fixed value. The predetermined threshold value α may be a variable value. When the predetermined threshold value α is a variable value, the predetermined threshold value α may be set based on, for example, the vehicle speed V.

As a result of the determination in step S5, when it is determined that the accelerator opening opening increase amount dAp (t) is not equal to or more than the predetermined threshold value α, or the accelerator opening opening increase amount dAp (t-1) is not less than the predetermined threshold value α ( Step S5: No), the ECU 100 does not perform the driving force suppressing operation (step S7) and the early start operation (step S8) described later. In this case, the ECU 100 may start the engine ENG using an existing method. For example, the ECU 100 ENGs the engine based on the target driving force calculated in step S2, the charging state of the battery 500 (so-called SOC (State Of Charge)), the power consumption of the electrical components included in the vehicle 1, and the like. May be determined whether or not it is necessary to start. When it is determined that it is necessary to start the engine ENG while the engine ENG is stopped, the ECU 100 may start the stopped engine ENG. After that, the ECU 100 ends the starting operation shown in FIG. After that, the ECU 100 performs the starting operation shown in FIG. 2 again after a certain period of time has elapsed. That is, the starting operation shown in FIG. 2 is repeated.

On the other hand, as a result of the determination in step S5, it is determined that the accelerator opening increase amount dAp (t) is equal to or more than the predetermined threshold value α and the accelerator opening opening increase amount dAp (t-1) is less than the predetermined threshold value α. (Step S5: Yes), the ECU 100 determines whether or not it is necessary to start the engine ENG (step S6). In this case as well, the ECU 100 may determine whether or not it is necessary to start the engine ENG based on the target driving force, the SOC, the power consumption of the electrical components, and the like.

If, as a result of the determination in step S6, it is determined that it is not necessary to start the engine ENG (step S6: No), the ECU 100 ends the starting operation shown in FIG.

On the other hand, when it is determined that it is necessary to start the engine ENG as a result of the determination in step S6 (step S6: Yes), the traveling state of the vehicle 1 is such that the accelerator opening opening increase amount dAp is less than the predetermined threshold value α. It is presumed that it is necessary to start the engine ENG at the timing of transition from the non-rapid acceleration state to the sudden acceleration state in which the accelerator opening opening increase amount dAp is equal to or higher than the predetermined threshold value α.

In this case, the target driving force becomes relatively large because the accelerator opening increase amount dAp is equal to or greater than the predetermined threshold value α (that is, the vehicle 1 needs to accelerate relatively rapidly). There is a high possibility that it is. Therefore, in order to satisfy a relatively large target driving force, it is desired to complete the start of the engine ENG relatively quickly. Here, the larger the cranking torque TC, the faster the start of the engine ENG can be completed. However, as the cranking torque TC becomes larger, the output used as the cranking torque TC (hereinafter referred to as "cranking motor output") among the motor outputs which are the outputs of the motor generator MG becomes larger, while the motor output becomes larger. Of these, the output used as the driving force of the vehicle 1 (hereinafter, referred to as "driving motor output") becomes small. As a result, there is a possibility that the acceleration will decrease (or the vehicle 1 will decelerate) in a situation where the vehicle 1 needs to accelerate relatively rapidly. Such a decrease in acceleration (that is, a drop) gives the driver the impression that the feeling of acceleration is significantly insufficient. That is, there is a possibility that the acceleration feeling of the vehicle 1 deteriorates.

Therefore, in the present embodiment, when it is necessary to newly start the engine ENG at the timing when the traveling state of the vehicle 1 changes from the non-rapid acceleration state to the sudden acceleration state, the engine is suppressed while suppressing the deterioration of the acceleration feeling. In order to complete the start of the ENG at an early stage, the ECU 100 performs a driving force suppressing operation (step S7) and an early start operation (step S8).

The driving force suppressing operation is increased by changing the running state of the vehicle 1 from the non-rapid acceleration state to the sudden acceleration state even after the running state of the vehicle 1 has changed from the non-rapid acceleration state to the sudden acceleration state. This is an operation for suppressing (typically maintaining) the fluctuation of the actual driving force of the vehicle 1 for a predetermined period with respect to the target driving force. According to the driving force suppressing operation, the running state of the vehicle 1 in the stopped state is maintained in the stopped state, or the running state of the vehicle 1 in the steady running state is maintained in the steady running state. .. Therefore, since the vehicle 1 does not start accelerating in the first place, a situation in which the acceleration drops cannot occur. Alternatively, since the driving force of the vehicle 1 in the slow acceleration state is maintained, the acceleration in the slow acceleration state is also maintained. Therefore, the acceleration does not drop. As a result, deterioration of the feeling of acceleration is suppressed.

However, as long as the fluctuation (particularly, increase) of the driving force is suppressed, the actual acceleration remains smaller than the acceleration based on the target driving force. For this reason, if the predetermined period in which the increase in the driving force is suppressed (hereinafter referred to as the "driving force suppressing period") is excessively long, the driver lacks a feeling of acceleration with respect to the amount of depression of the accelerator pedal. You may get the impression that you are there. Therefore, the driving force suppression period is set to a short period so that the driver does not care that the acceleration feeling is insufficient with respect to the amount of depression of the accelerator pedal.

The early start operation is to increase the cranking torque TC as much as possible from the start of the engine ENG until the start of the engine ENG is completed (or until the above-mentioned driving force suppression period elapses). , This is an operation for completing the start of the engine ENG relatively quickly.

Hereinafter, the driving force suppressing operation and the early starting operation will be described in order.

(3) Driving force suppressing operation The driving force suppressing operation will be described with reference to FIG. FIG. 3 is a flowchart showing the flow of the driving force suppressing operation.

As shown in FIG. 3, the ECU 100 sets the driving force change rate to zero (step S71). The driving force change rate is a parameter indicating whether or not the driving force of the vehicle 1 is changed. When the driving force change rate is set to zero, the ECU 100 does not change the driving force. Therefore, the ECU 100 controls the motor generator MG so that the running motor output matches the running motor output at the time when the running state of the vehicle 1 that was not in the sudden acceleration state transitions to the sudden acceleration state. As a result, the acceleration of the vehicle 1 does not drop.

While the driving force change rate is set to zero, the ECU 100 updates the driving force suppression counter C by adding the driving force suppression counter C to the driving force suppression counter C each time the predetermined time dT elapses (step). S72). The predetermined time dT corresponds to, for example, the calculation cycle in the driving force suppression operation (that is, the cycle in which the operations of steps S72 to S73 are performed). After that, the ECU 100 determines whether or not the driving force suppression counter C is larger than the upper limit time T0 (step S73).

The upper limit time T0 is the upper limit of the driving force suppression period. As described above, the upper limit time T0 is set to a short time so that the driver does not care that the acceleration feeling is insufficient with respect to the amount of depression of the accelerator pedal. The upper limit time T0 may be a fixed value or a variable value. When the upper limit time T0 is a variable value, the upper limit time T0 may be set based on, for example, the vehicle speed V and the accelerator opening opening increase amount dAp. For example, the upper limit time T0 may be set based on a map that defines the relationship between the vehicle speed V, the accelerator opening opening amount increase dAp, and the upper limit time T0.

If, as a result of the determination in step S73, it is determined that the driving force suppression counter C is not larger than the upper limit time T0 (step S73: No), the operations after step S71 are repeated. That is, the running motor output continues to match the running motor output at the time when the running state of the vehicle 1 that was not in the sudden acceleration state transitions to the sudden acceleration state. On the other hand, if it is determined as a result of the determination in step S73 that the driving force suppression counter C is larger than the upper limit time T0 (step S73: Yes), the ECU 100 ends the driving force suppression operation shown in FIG. At the end of the driving force suppressing operation, the ECU 100 sets the driving force change rate to a value other than zero. As a result, fluctuations in driving force are allowed. In this case, the ECU 100 may change the driving force according to the target driving force and the like. For example, the ECU 100 may control the motor generator MG so as to increase the driving force in order to realize the acceleration commensurate with the target driving force. Further, the ECU 100 may reduce the cranking torque TC (that is, reduce the cranking motor output) in order to increase the driving force (that is, increase the traveling motor output).

In step 73 of FIG. 3, the ECU 100 newly acquires the accelerator opening Ap (t) in addition to or instead of determining whether or not the driving force suppression counter C is larger than the upper limit time T0. The accelerator opening opening increase amount dAp (t) may be newly calculated, and it may be determined whether or not the newly calculated accelerator opening opening increase amount dAp (t) is smaller than the predetermined threshold value α'. The predetermined threshold value α'is a value obtained by subtracting a certain margin th from the predetermined threshold value α. When the accelerator opening opening increase amount dAp (t) is smaller than the predetermined threshold value α', the traveling state of the vehicle 1 is in a non-rapid acceleration state (or in a deceleration state in which the vehicle 1 is decelerating). Presumed. In this case, since it is not necessary for the vehicle 1 to accelerate relatively rapidly, it is necessary to complete the start of the engine ENG relatively quickly until the exceptional processing of suppressing the fluctuation of the driving force is performed. The sex becomes smaller. Therefore, even when the accelerator opening opening increase amount dAp (t) is smaller than the predetermined threshold value α', the ECU 100 may end the driving force suppressing operation shown in FIG.

(4) Early Start Operation Subsequently, the early start operation will be described with reference to FIG. FIG. 4 is a flowchart showing the flow of the early start operation.

As shown in FIG. 4, the ECU 100 determines whether or not the accelerator opening Ap (t) is equal to or greater than the predetermined threshold value β (step S81). The predetermined threshold value β determines the situation in which a relatively large engine output is required to satisfy the target driving force and the situation in which a relatively small engine output is sufficient to satisfy the target driving force. ) Is a parameter set so that it can be specified.

If it is determined as a result of the determination in step S81 that the accelerator opening Ap (t) is not equal to or greater than the predetermined threshold value β (step S81: No), the ECU 100 sets the target value of the cranking torque TC to be relatively small. The cranking torque is set to TCl (step S833). Further, the ECU 100 sets the cranking rate TCR, which is the target value of the increase speed of the cranking torque TC, to a relatively small cranking rate TCRl (step S833). In this case, the ECU 100 controls the motor generator MG so as to output the cranking torque TC that increases to the relatively small cranking torque TCl at the relatively small cranking rate TCRl to the engine ENG. As a result, the engine shaft of the engine ENG is rotated by the cranking torque TC, so that the rotation speed Ne of the engine ENG increases. At this time, the ECU 100 is for cranking, which is necessary for the motor output to output the traveling motor output Pv and the cranking torque TCl necessary for suppressing the fluctuation of the driving force (that is, maintaining the driving force). The motor generator MG is controlled so as to match the sum of the motor output Pcrank.

After the cranking torque TCl is output, the ECU 100 acquires the engine ENG rotation speed Ne (step S834), and determines whether or not the acquired rotation speed Ne becomes a relatively small predetermined rotation speed Ne or more. Determine (step S835). The predetermined rotation speed Ne is a situation in which the increase speed of the rotation speed Ne may be decreased after the early start operation is completed, and the early start operation is continued to maintain the increase speed of the rotation speed Ne (that is, the engine ENG). It is a parameter set so that the situation in which the rotation speed Ne needs to be increased relatively quickly for the early completion of the start of the rotation speed Ne can be specified from the rotation speed Ne.

If, as a result of the determination in step S835, it is determined that the rotation speed Ne is not equal to or higher than the predetermined rotation speed Nel (step S835: No), the operations after step S81 are repeated. On the other hand, if it is determined that the rotation speed Ne is equal to or higher than the predetermined rotation speed Ne as a result of the determination in step S835 (step S835: Yes), the ECU 100 ends the early start operation shown in FIG. In this case, the ECU 100 reduces the cranking torque TC. Further, the ECU 100 starts combustion of the fuel in the combustion chamber by supplying fuel to the combustion chamber of the engine ENG at a desired timing. As a result, the start of the engine ENG is completed. However, if the combustion of fuel in the combustion chamber of the engine ENG has already started before the early start operation is completed, it is sufficient for the ECU 100 to continue supplying the fuel to the combustion chamber as it is.

On the other hand, when it is determined as a result of the determination in step S81 that the accelerator opening Ap (t) is equal to or greater than the predetermined threshold value β (step S81: Yes), the ECU 100 sets the target value of the cranking torque TC. The relatively large cranking torque TCh (TCh> TCl) is set (step S823). Further, the ECU 100 sets the cranking rate TCR to a relatively large cranking rate TCRh (TCRh> TCRl) (step S823). In this case, the ECU 100 controls the motor generator MG so as to output the cranking torque TC, which increases to a relatively large cranking torque TCh at a relatively large cranking rate TCRh, to the engine ENG. As a result, the engine shaft of the engine ENG is rotated by the cranking torque TC, so that the rotation speed Ne of the engine ENG increases. Also in this case, the ECU 100 also cranks the motor output to output the traveling motor output Pv and the cranking torque TCh necessary to suppress the fluctuation of the driving force (that is, maintain the driving force). The motor generator MG is controlled so as to match the sum of the motor outputs Prank. However, in order to secure a relatively large cranking torque TCh, the ECU 100 may control the motor generator MG so that the motor output matches the maximum value Pmax corresponding to the output limit value Wout of the battery 500. Good.

After the cranking torque TC is output, the ECU 100 acquires the engine ENG rotation speed Ne (step S824), and the acquired rotation speed Ne becomes equal to or higher than a relatively large predetermined rotation speed Neh (Neh> Nel). It is determined whether or not it has become (step S825). The predetermined rotation speed Neh is a parameter set from the same viewpoint as the predetermined rotation speed Nel.

If, as a result of the determination in step S825, it is determined that the rotation speed Ne is not equal to or higher than the predetermined rotation speed Neh (step S825: No), the operations after step S823 are repeated. On the other hand, when it is determined as a result of the determination in step S825 that the rotation speed Ne is equal to or higher than the predetermined rotation speed Neh (step S825: Yes), the ECU 100 ends the early start operation shown in FIG. In this case, the ECU 100 reduces the cranking torque TC. Further, the ECU 100 starts combustion of the fuel in the combustion chamber by supplying fuel to the combustion chamber of the engine ENG at a desired timing. As a result, the start of the engine ENG is completed. However, if the combustion of fuel in the combustion chamber of the engine ENG has already started before the early start operation is completed, it is sufficient for the ECU 100 to continue supplying the fuel to the combustion chamber as it is.

(5) State of Vehicle 1 Performing Starting Operation Subsequently, a specific example of the state of vehicle 1 performing the starting operation will be described with reference to FIG. FIG. 5 is a timing chart showing a specific example of the state of the vehicle 1 in which the starting operation is performed.

As shown in FIG. 5, at time t50, the vehicle 1 is running steadily in the EV mode. In this case, the driver depresses the accelerator pedal by a certain amount so that the vehicle 1 runs steadily. Further, the target driving force according to the accelerator opening degree Ap is satisfied by the motor output (that is, the running motor output).

After that, at time t51, the driver sharply increases the amount of depression of the accelerator pedal so that the amount of increase in accelerator opening dAp (t) becomes equal to or higher than the predetermined threshold value α. In this case, after the time t51, the accelerator opening Ap suddenly increases. As a result, it is determined that the accelerator opening opening increase amount dAp (t) becomes equal to or higher than the predetermined threshold value α at the time t52. That is, at time t52, it is determined that the traveling state of the vehicle 1 changes from the non-rapid acceleration state (in the example shown in FIG. 5, the steady traveling state) to the rapid acceleration state. Further, the target driving force also increases as the accelerator opening degree Ap increases. As a result, after time t52, the target driving force increases to the extent that it is necessary to start the engine ENG. Therefore, at time t52, the above-mentioned driving force suppressing operation and early starting operation are performed.

Specifically, by the driving force suppressing operation, the driving force after the time t52 is maintained as the driving force at the time t52. As a result, the acceleration after the time t52 is maintained at zero, which is the acceleration at the time t52. This driving force suppressing operation ends at time t53 when the upper limit time T0 has elapsed from time t52. As a result, after the time t53, the driving force increases according to the target driving force, and the acceleration of the vehicle 1 increases.

Further, since it is determined that the accelerator opening dAp (t) is less than the predetermined threshold value β at the time t52, the engine of the engine ENG with a relatively small cranking torque TCl after the time t52 due to the early start operation. The shaft is rotated. As a result, after time t52, the engine ENG rotation speed Ne increases. After that, since it is determined that the accelerator opening dAp (t) becomes equal to or higher than the predetermined threshold value β at the time t54, the engine shaft of the engine ENG is rotated with a relatively large cranking torque TCh after the time t54. As a result, the rate of increase of the engine ENG rotation speed Ne becomes larger after the time t54 than before the time t54. After that, at time t53, it is determined that the rotation speed Ne becomes equal to or higher than the predetermined rotation speed Neh. As a result, the early start operation ends at time t53. Therefore, after the time t53, the cranking torque TC decreases and the speed of increase of the engine ENG rotation speed Ne decreases. Further, after the time t53, since the driving force suppressing operation is completed, the driving force increases as the cranking torque TC decreases. Note that FIG. 5 shows an example in which the time at which the early start operation ends coincides with the time at which the driving force suppression operation ends.

Note that FIG. 5 is driven in order to give priority to suppressing deterioration of the feeling of acceleration in a situation where it is necessary to newly start the engine ENG at the timing when the traveling state of the vehicle 1 changes from the non-rapid acceleration state to the sudden acceleration state. The state of the vehicle 1 (particularly, driving force, acceleration, cranking torque TC, and rotation speed Ne) when the starting operation of the first comparative example in which the force matches the target driving force is performed is shown by a thick dotted line. .. In the first comparative example, after the time t52, the driving force becomes large so as to correspond to the increased target driving force. As a result, deterioration of the feeling of acceleration is suppressed. However, in the first comparative example, after the time t52, the cranking torque TC becomes excessively small due to the increase in the driving force. As a result, it takes a relatively long time to complete the start of the engine ENG.

Further, FIG. 5 shows that in a situation where it is necessary to newly start the engine ENG at the timing when the traveling state of the vehicle 1 changes from the non-rapid acceleration state to the sudden acceleration state, priority is given to the early completion of the engine ENG start. In addition, the state of the vehicle 1 (particularly, driving force, acceleration, cranking torque TC and rotation speed Ne) when the starting operation of the second comparative example for maximizing the cranking torque TC is performed is a thick one-point chain line. It is shown by. In the second comparative example, after the time t52, the engine ENG is started with the cranking torque TC maximized to the maximum, so that the start of the engine ENG is completed early. However, in the second comparative example, the driving force is greatly reduced due to the increase in the cranking torque TC. As a result, the acceleration may drop (or the vehicle 1 may decelerate) after the time t52. Therefore, the feeling of acceleration may be significantly deteriorated.

Compared with these first and second comparative examples, in the present embodiment, in a situation where it is necessary to newly start the engine ENG at the timing when the traveling state of the vehicle 1 changes from the non-rapid acceleration state to the sudden acceleration state. It is possible to complete the start of the engine ENG at an early stage while suppressing the deterioration of the feeling of acceleration. That is, the present embodiment is advantageous in comparing the first and second comparative examples in that both the deterioration of the feeling of acceleration and the early completion of the start of the engine ENG can be appropriately compatible with each other. ..

(6) Modification Example Next, a modification will be described.

(6-1) Deformed Example of Starting Operation First, a modified example of the starting operation will be described with reference to FIG. FIG. 6 is a flowchart showing a flow of a modified example of the starting operation. The same steps as the processes performed in the starting operation shown in FIG. 2 are given the same step numbers, and detailed description thereof will be omitted.

As shown in FIG. 6, in the modified example, the processes from step S1 to step S4 described above are performed. After that, also in the modified example, the ECU 100 determines whether the accelerator opening opening increase amount dAp (t) is equal to or more than the predetermined threshold value α and whether the accelerator opening opening increase amount dAp (t-1) is less than the predetermined threshold value α. Whether or not it is determined (step S5a). In the modified example, the ECU 100 further determines whether or not the accelerator opening opening increase amount dAp (t-1) is larger than zero (step S5a). That is, the ECU 100 determines whether or not the situation in which the accelerator opening opening increase amount dAp is larger than zero continues.

A situation in which the accelerator opening increase amount dAp is larger than zero corresponds to a situation in which the driver continues to depress the accelerator pedal (in other words, the accelerator pedal depressing amount continues to increase). It is presumed that the driver who keeps depressing the accelerator pedal has an intention to accelerate the vehicle 1. Therefore, it can be said that the determination operation in step S5 is equivalent to the operation of determining whether or not the vehicle 1 is in a state of continuous acceleration.

Further, as described above, in the determination operation of step S5, does the traveling state of the vehicle 1 transition from the non-rapid acceleration state (specifically, the stopped state, the steady traveling state and the slow acceleration state) to the sudden acceleration state? It is equivalent to the operation of determining whether or not. Therefore, the determination operation in step S5 is substantially equivalent to the operation of determining whether or not the traveling state of the vehicle 1 transitions from the slow acceleration state to the sudden acceleration state.

As a result of the determination in step S5a, the accelerator opening increase amount dAp (t) is not equal to or more than the predetermined threshold α, the accelerator opening increase amount dAp (t-1) is not less than the predetermined threshold α, or the accelerator opening increase amount dAp (t− If it is determined that 1) is not greater than zero (step S5a: No), the ECU 100 does not perform the driving force suppression operation (step S7) and the early start operation (step S8a).

On the other hand, as a result of the determination in step S5a, the accelerator opening increase amount dAp (t) is equal to or more than the predetermined threshold value α, the accelerator opening opening increase amount dAp (t-1) is less than the predetermined threshold value α, and the accelerator opening increase When it is determined that the amount dAp (t-1) is larger than zero (step S5a: Yes), the ECU 100 determines whether or not it is necessary to start the engine ENG (step S6).

If, as a result of the determination in step S6, it is determined that it is not necessary to start the engine ENG (step S6: No), the ECU 100 ends the starting operation shown in FIG.

On the other hand, when it is determined that it is necessary to start the engine ENG as a result of the determination in step S6 (step S6: Yes), the traveling state of the vehicle 1 is such that the accelerator opening opening increase amount dAp is less than the predetermined threshold value α. It is presumed that it is necessary to start the engine ENG at the timing of transition from the slow acceleration state where the vehicle accelerates under the above-mentioned situation to the sudden acceleration state where the accelerator opening increase amount dAp becomes the predetermined threshold value α or more. To. Also in this case, the ECU 100 performs the driving force suppressing operation (step S7) and the early start operation (step S8a). Since the driving force suppressing operation of the modified example is the same as the driving force suppressing operation shown in FIG. 3 described above, detailed description thereof will be omitted. On the other hand, in the early start operation of the modified example, the upper limit value TCmax of the cranking torque TC is set in order to secure the driving force capable of maintaining the acceleration of the hybrid vehicle 1 in the slow acceleration state. It is different from the early start operation shown in 4. Hereinafter, a modified example of the early start operation will be further described.

(6-2) Modification Example of Early Start Operation A modification of the early start operation will be described with reference to FIG. 7. FIG. 7 is a flowchart showing a flow of a modified example of the early start operation. The same process as the process performed in the early start operation shown in FIG. 4 is given the same step number, and detailed description thereof will be omitted.

As shown in FIG. 7, also in the modified example, the ECU 100 determines whether or not the accelerator opening degree Ap (t) is equal to or greater than the predetermined threshold value β (step S81). If, as a result of the determination in step S81, it is determined that the accelerator opening Ap (t) is not equal to or greater than the predetermined threshold value β (step S81: No), the processing of steps S833 to S835 described above is performed even in the modified example. Will be.

On the other hand, when it is determined as a result of the determination in step S81 that the accelerator opening Ap (t) is equal to or greater than the predetermined threshold value β (step S81: Yes), the ECU 100 determines the actual driving force F of the vehicle 1. Calculate (step S821a). At this stage, since the motor generator MG has not yet output the cranking torque TC, the driving force F substantially matches the value obtained by converting the motor output into the driving force. Further, the ECU 100 acquires the rotation speed Ng of the motor generator MG (step S821a).

After that, the ECU 100 sets the upper limit value TCmax of the cranking torque TC based on the driving force F and the rotation speed Ng (step S822a). As described above, the upper limit value TCmax is set in order to secure the running motor output capable of maintaining the acceleration of the vehicle 1 in the slow acceleration state. Here, the traveling motor output Pv required to maintain the acceleration of the vehicle 1 in the slow acceleration state can be calculated from the formula of traveling motor output Pv = driving force F × vehicle speed V. Further, as described above, the maximum value Pmax of the motor output substantially coincides with the output limit value Wout of the battery 500. Therefore, in order to secure the traveling motor output Pv capable of maintaining the acceleration of the vehicle 1 in the slow acceleration state, the cranking motor output Prank must satisfy the condition of Prank ≦ Pmax-Pv. The relationship between the cranking torque TC and the cranking motor output Pcrank can be expressed by the mathematical formula TC = Prank × 60 / (2 × π × Ng). As a result, the cranking torque TC capable of maintaining the acceleration of the vehicle 1 in the slow acceleration state satisfies the formula TC ≦ (Pmax−Pv) × 60 / (2 × π × Ng). Therefore, the upper limit value TCmax is (Pmax-Pv) × 60 / (2 × π × Ng).

After that, also in the modified example, the processes of steps S823 to S825 described above are performed. However, in the modified example, the ECU 100 controls the motor generator MG so that the cranking torque TC does not exceed the upper limit value TCmax.

(6-3) State of Vehicle 1 in which a Modified Example of Starting Operation is Performed Subsequently, a specific example of a state of vehicle 1 in which a modified example of starting operation is performed will be described with reference to FIG. FIG. 8 is a timing chart showing a specific example of the state of the vehicle 1 in which a modified example of the starting operation is performed.

As shown in FIG. 8, at time t80, the vehicle 1 is running steadily in the EV mode. After that, at time t81, the driver gradually increases the amount of depression of the accelerator pedal so that the amount of increase in accelerator opening dAp (t) does not exceed the predetermined threshold value α. In this case, after the time t81, the accelerator opening degree Ap increases. The target driving force also increases as the accelerator opening Ap increases. As a result, the vehicle 1 accelerates. However, at time t81, it is assumed that the target driving force does not increase to the extent that it is necessary to start the engine ENG. Further, although the vehicle 1 is accelerating, the accelerator opening opening increase amount dAp (t) does not exceed the predetermined threshold value α. Therefore, it is estimated that the traveling state of the vehicle 1 is a slow acceleration state (that is, it has not transitioned to a sudden acceleration state). Therefore, the above-mentioned driving force suppressing operation and early starting operation are not performed.

After that, at time t82, the driver sharply increases the amount of depression of the accelerator pedal so that the amount of increase in accelerator opening dAp (t) becomes equal to or higher than the predetermined threshold value α. In this case, after the time t82, the accelerator opening Ap increases more rapidly than before the time t82. As a result, it is determined that the accelerator opening opening increase amount dAp (t) becomes equal to or higher than the predetermined threshold value α at the time t83. That is, at the time t83, it is determined that the traveling state of the vehicle 1 changes from the slow acceleration state to the rapid acceleration state. Further, the target driving force also increases as the accelerator opening degree Ap increases. As a result, after time t83, the target driving force increases to the extent that it is necessary to start the engine ENG. Therefore, at time t83, the above-mentioned driving force suppressing operation and early starting operation are performed.

Specifically, by the driving force suppressing operation, the driving force after the time t83 is maintained as the driving force at the time t83. As a result, the acceleration after the time t83 is maintained as the acceleration at the time t83. This driving force suppressing operation ends at the time t84 when the upper limit time T0 has elapsed from the time t83. As a result, after the time t84, the driving force increases according to the target driving force, and the acceleration of the vehicle 1 increases.

Further, since the accelerator opening dAp (t) is equal to or higher than the predetermined threshold value β at the time t83, the engine shaft of the engine ENG is rotated with a relatively large cranking torque TCh by the early start operation. As a result, after time t83, the engine ENG rotation speed Ne increases. Further, FIG. 8 shows an example in which the cranking torque TCh coincides with the upper limit value TCmax. As a result, the running motor output capable of maintaining the acceleration at the time t83 (that is, not causing a drop) is appropriately secured.

After that, at time t84, it is determined that the rotation speed Ne becomes equal to or higher than the predetermined rotation speed Neh. As a result, the early start operation ends at time t84. As a result, after the time t84, the cranking torque TC decreases and the speed of increase of the engine ENG rotation speed Ne decreases. Further, after the time t84, since the driving force suppressing operation is completed, the driving force increases as the cranking torque TC decreases. Note that FIG. 8 shows an example in which the time at which the early start operation ends coincides with the time at which the driving force suppression operation ends.

Also in FIG. 8, similarly to FIG. 5, the state of the vehicle 1 when the starting operation of the first comparative example is performed is shown by a thick dotted line, and the starting operation of the second comparative example is performed. The state of vehicle 1 is indicated by a thick alternate long and short dash line. Compared with these first and second comparative examples, in the modified example, the feeling of acceleration is felt in a situation where the engine ENG needs to be newly started at the timing when the traveling state of the vehicle 1 changes from the slow acceleration state to the sudden acceleration state. It is possible to complete the start of the engine ENG at an early stage while suppressing the deterioration of the engine ENG. Therefore, even in the modified example, the above-mentioned effect can be appropriately enjoyed.

In particular, in the modified example, the upper limit value TCmax of the cranking torque TC is set from the viewpoint of ensuring the running motor output capable of maintaining the acceleration of the vehicle 1 in the slow acceleration state. Therefore, when it is necessary to start the engine ENG in a situation where the vehicle 1 is already accelerating in a slow acceleration state, the start of the engine ENG is completed early while suppressing the deterioration of the acceleration feeling more appropriately. Can be made to.

It should be noted that the present invention can be appropriately modified within the scope of the claims and within the range not contrary to the gist or idea of the invention that can be read from the entire specification, and the vehicle control device accompanied by such a modification is also included in the technical idea of the present invention. included.

1 vehicle 100 ECU
500 Battery ENG Engine MG Motor Generator

Claims (1)

It is possible to travel by using at least one output of the internal combustion engine and the electric motor as a driving force for traveling, and by rotating the internal combustion engine with a cranking torque using at least a part of the output of the electric motor. A vehicle control device that controls a vehicle that can start the internal combustion engine that is stopped.
Timing of transition from the first state in which the amount of increase in the accelerator opening per unit time is less than a predetermined amount to the second state in which the traveling state of the vehicle accelerates in a situation where the amount of increase is greater than or equal to the predetermined amount. When the internal combustion engine is started in, the internal combustion engine is started by the cranking torque, and the fluctuation of the driving force is suppressed until a predetermined time elapses after the start of the internal combustion engine is started. Moreover, the increase in the driving force is allowed after the predetermined time has elapsed from the start of the start of the internal combustion engine .
When the internal combustion engine is started at the timing of transition from the third state in which the traveling state of the vehicle accelerates in a situation where the increase amount is less than the predetermined amount to the second state, the power storage device is the electric motor. A value obtained by subtracting the actual output of the electric motor at the time when the traveling state transitions from the third state to the second state from the maximum value of the output of the electric motor that can be output using the electric power that can be supplied to the motor. A vehicle control device characterized in that the internal combustion engine is started with the cranking torque set to be smaller than the torque conversion value of .

Images