WO2018168389A1

WO2018168389A1 - Vehicle control apparatus

Info

Publication number: WO2018168389A1
Application number: PCT/JP2018/006568
Authority: WO
Inventors: 石田　稔; 工藤　弘康
Original assignee: 株式会社デンソー
Priority date: 2017-03-15
Filing date: 2018-02-22
Publication date: 2018-09-20
Also published as: JP2018150018A; DE112018001350T5; JP6705403B2

Abstract

This vehicle control apparatus is applied to a vehicle (10) provided with an engine (11), a clutch device (17) that is provided to a power transmission path connected to an output shaft (12) of the engine, and a regeneration device (13) that recovers kinetic energy of the vehicle via the output shaft. The vehicle control apparatus is provided with: a travel control unit that executes inertial traveling of the vehicle by cutting off the clutch device in accordance with establishment of an inertial traveling execution condition, and executes transition from the inertial traveling to regeneration traveling using the regeneration device by executing adjustment of the engine rotation speed and connection of the clutch device in accordance with establishment of a regeneration execution condition during the inertial traveling; and an estimation unit that, when a braking operation is performed as the regeneration execution condition during the inertial traveling, estimates consumed energy used by the adjustment of the engine rotation speed, and estimates regeneration energy recovered by the regeneration traveling. The travel control unit executes the transition from inertial traveling to regeneration traveling on the basis of a comparison between the consumed energy and the regeneration energy.

Description

Vehicle control device

Cross-reference of related applications

This application is based on Japanese Patent Application No. 2017-049745 filed on March 15, 2017, the contents of which are incorporated herein by reference.

This disclosure relates to a vehicle control device.

In recent years, for the purpose of improving fuel efficiency and the like, a technology for putting a vehicle in an inertial running state by disengaging a clutch device provided between an engine and a transmission when an accelerator is off while the vehicle is running has been put into practical use (for example, Patent Document 1). This inertial traveling is a technology that uses the kinetic energy of a vehicle as it is for traveling, and it is possible to improve fuel efficiency by extending the traveling distance of the vehicle.

On the other hand, so-called regenerative travel is known in which kinetic energy at the time of deceleration of the vehicle is recovered as regenerative energy to improve the energy efficiency of the vehicle. For example, in regenerative power generation that converts kinetic energy into electrical energy, the motor functions as a generator by the rotation of an engine output shaft or the like, and the electrical energy generated by the power generation is stored in a battery.

Japanese Unexamined Patent Publication No. 2016-22727

Here, from the viewpoint of further improvement in fuel consumption, it is desirable to be able to travel appropriately using each travel while enabling mutual switching between inertial travel and regenerative travel. By the way, when shifting from inertial traveling to regenerative traveling, it is necessary to connect a clutch that is in a disconnected state. In this case, in order to reduce vibration, noise, and the like when the clutch is connected, it is desirable to connect the clutch with the engine speed increased, which involves energy consumption. Therefore, depending on the embodiment of the regenerative travel, it is considered that the energy consumed for increasing the engine rotation speed may be larger than the energy recovered by the regenerative travel. In such a case, it is not preferable from the viewpoint of improving fuel consumption.

The present disclosure has been made in view of the above circumstances, and a main purpose thereof is to provide a vehicle control device capable of appropriately switching between inertial traveling and regenerative traveling.

In the first means,
Applied to a vehicle comprising an engine as a travel drive source, a clutch device provided in a power transmission path connected to the output shaft of the engine, and a regenerative device for recovering kinetic energy of the vehicle via the output shaft,
In response to the establishment of predetermined inertial running conditions, the clutch device is disengaged to perform inertial running of the vehicle, and in accordance with the establishment of predetermined regeneration execution conditions during inertial running, the engine rotation speed is adjusted. A travel control unit that performs connection to the regenerative travel using the regenerative device from the inertia travel by performing connection of the clutch device;
In the case where a braking operation is performed as the regeneration execution condition during the inertia traveling, an estimation is performed for estimating the energy consumed by adjusting the engine rotation speed and estimating the regeneration energy recovered by the regeneration traveling. And
With
The traveling control unit performs a transition from the inertia traveling to the regenerative traveling based on a comparison between the consumed energy and the regenerative energy.

移行 When shifting from inertial running to regenerative running, it is necessary to adjust the engine speed and connect the clutch device. This adjustment of the engine speed involves energy consumption. Therefore, from the viewpoint of energy efficiency, it is desirable to shift to regenerative travel in consideration of energy consumption.

In this regard, in the above configuration, when a braking operation is performed as a predetermined regeneration execution condition during inertial traveling, the energy consumption consumed by adjusting the engine speed is estimated, and the regeneration recovered by the regenerative traveling is estimated. Estimate energy. Then, based on the comparison between the consumed energy and the regenerative energy, the transition from the inertia travel to the regenerative travel is performed. In this case, the shift to the regenerative travel can be suppressed from the viewpoint of energy efficiency, for example, by shifting to the regenerative travel in consideration of the energy consumption. In addition, the frequency of switching from coasting to regenerative traveling can be suppressed, leading to improved drivability. Thereby, inertial running and regenerative running can be switched appropriately.

Note that the brake operation as the regeneration execution condition may be a brake pedal operation by a driver or a deceleration determination by a vehicle operation control unit (for example, an automatic operation control unit). In addition, when a braking operation is performed during inertial running, it is considered that the engine rotational speed is adjusted by driving the rotating machine, and the electrical energy required to drive the rotating machine is estimated as consumed energy. Good.

The second means includes a determination unit that determines that the regenerative energy estimated by the estimation unit is greater than the consumed energy, and the travel control unit has the regenerative energy greater than the consumed energy. When it is determined, a transition from the inertia traveling to the regenerative traveling is performed, and when it is determined that the regenerative energy is smaller than the consumed energy, the inertia traveling is maintained.

When it is determined that the regenerative energy is larger than the consumed energy, the transition from the inertial running to the regenerative running is performed, so that the energy more than the consumed energy can be recovered by the regenerative running. In addition, since coasting is maintained when it is determined that the regenerative energy is smaller than the consumed energy, the fuel efficiency effect by coasting can be obtained, and the shift to unfavorable regeneration from the viewpoint of energy efficiency is suppressed. be able to.

In the third means, the estimation unit estimates the energy consumption based on the vehicle speed when the brake operation as the regeneration execution condition is performed during the inertial traveling.

The energy consumption is energy required to rotate the output shaft of the engine up to the target engine speed, and is considered to correlate with the vehicle speed. That is, when the vehicle speed is high, the target engine rotation speed increases, and energy consumption increases accordingly. Considering this point, the energy consumption is estimated based on the vehicle speed, so that the energy consumption can be accurately estimated. As a result, it is possible to appropriately determine the transition from inertial travel to regenerative travel.

In the fourth means, the estimation unit estimates the regenerative energy based on the amount of brake operation when the brake operation is performed as the regeneration execution condition during the inertia traveling.

Regenerative energy is considered to correlate with the amount of brake operation. For example, when the brake operation amount is large, the driver's request for deceleration is large and the regenerative energy is also large. Considering this point, the regenerative energy is estimated based on the brake operation amount, so that the regenerative energy can be estimated with high accuracy. As a result, it is possible to appropriately determine the transition from inertial travel to regenerative travel.

The fifth means includes a setting unit that sets a duration of the regenerative travel when the brake operation is performed during the inertia travel, and the estimation unit determines the brake operation amount and the duration. Based on this, the regenerative energy is estimated.

Regenerative energy is considered to correlate with the duration of regenerative travel. For example, the longer the duration of regenerative travel, the greater the regenerative energy. Considering this point, when the braking operation is performed during coasting, the duration of regenerative travel is set, and the regenerative energy is estimated based on the set duration and the amount of brake operation. Energy can be estimated accurately.

The sixth means includes a storage unit that stores the duration when the regenerative travel is performed, and the setting unit is configured to perform the duration based on the history of the duration stored in the storage unit. Set.

When the regenerative driving is performed, the duration is stored, and the duration is set based on the history of the stored duration, so the duration is set according to the tendency of the regenerative driving for each vehicle. be able to. Thereby, a continuation time can be set suitably.

In the seventh means, the storage unit stores the duration for each of a plurality of vehicle driving conditions, and the setting unit, when the brake operation is performed during the inertia running, The history is acquired according to the traveling condition of the vehicle, and the duration is set based on the history.

The regeneration time of regenerative driving is thought to affect the driving conditions in each case. For example, it is considered that the regeneration time becomes longer as the vehicle speed increases. Considering this point, when a braking operation is performed during inertial traveling, a history of duration is acquired according to the traveling condition of the vehicle, and the duration is set based on the history. In this case, by acquiring the history of the duration according to each traveling condition, the duration can be set in consideration of the conditions affecting the regeneration time. As a result, the duration time can be set with high accuracy in accordance with each operating condition.

In an eighth means, the regenerative device is a rotating electrical machine that performs regenerative power generation that recovers kinetic energy of the vehicle as electrical energy, and based on a state of a storage battery that stores power generated by the rotating electrical machine, A correction unit that corrects the regenerative energy estimated by the estimation unit is provided.

In the configuration in which the electric power generated by the regenerative power generation by the rotating electrical machine is stored in the storage battery, for example, when the storage battery is nearly fully charged, it is considered that the energy recovery is limited even if the regenerative travel is shifted from the inertia travel. Considering this point, the regenerative energy is corrected based on the state of the storage battery. In this case, in addition to the energy balance, the shift to the regenerative travel that is disadvantageous from the viewpoint of energy efficiency can be suitably suppressed by taking into account the state on the energy storage side.

In a ninth means, the regenerative device is a rotating electrical machine that performs regenerative power generation that recovers kinetic energy of the vehicle as electrical energy, and the regenerator estimated by the estimation unit based on a state of the rotating electrical machine. A correction unit for correcting energy is provided.

In a configuration in which regenerative power generation is performed by a rotating electrical machine, for example, when the temperature inside the rotating electrical machine is high, it is considered that energy recovery is limited even when the inertia traveling is changed to the regenerative traveling. Considering this point, the regenerative energy is corrected based on the state of the rotating electrical machine. In this case, in addition to the energy balance, the transition to the regenerative travel that is disadvantageous from the viewpoint of energy efficiency can be suitably suppressed by taking into account the state on the energy recovery side.

In the tenth means, in the vehicle, it is possible to apply a rotational force to the output shaft by a rotating machine, and the traveling control unit changes the engine rotational speed when shifting from the inertia traveling to the regenerative traveling. Is less than a predetermined value, the rotating machine is operated to increase the engine rotation speed, and if the engine rotation speed is equal to or higher than a predetermined value, the engine rotation speed is increased by combustion of the engine.

When increasing the engine rotation speed, the combustion efficiency of the engine is poor in the low rotation speed range, so it is considered that driving by a rotating machine is more efficient than engine combustion. On the other hand, the combustion efficiency of the engine is good in the high rotation speed region. Considering this point, when shifting from inertial running to regenerative running, if the engine rotation speed is less than a predetermined value, the rotating machine is operated, and if the engine rotation speed is higher than a predetermined value, the engine rotation speed is increased by engine combustion. Since it was made to do, the energy consumption at the time of transfering to regenerative driving | running can be made as small as possible, and energy efficiency can be improved.

In an eleventh means, the regenerative device is a rotating machine, and is applied to a vehicle in which a transmission gear ratio between the output shaft and a rotating shaft of the rotating machine is variable. A shift control unit for changing the engine rotation speed to the side that suppresses the decrease is provided.

In the above configuration, in inertial running, the gear ratio between the engine output shaft and the rotating shaft of the rotating machine is changed to the side that suppresses the decrease in engine rotating speed. In this case, by changing the gear ratio, the inertia of the engine during inertial running increases, and the period during which the engine output shaft rotates can be extended. This makes it difficult for the engine rotation speed to decrease after the start of inertial traveling. For example, when shifting from inertial traveling to normal traveling immediately, rotation of the engine output shaft is ensured and energy consumption associated with the transition is reduced. be able to.

In a twelfth means, the speed ratio is a ratio of a rotational speed of the rotary shaft of the rotating machine to a rotational speed of the output shaft, and the speed change control unit is configured to execute the predetermined inertial running condition. The speed ratio is made larger than before, and the speed ratio is made smaller when the inertia running is released.

¡When traveling by combustion of the engine, the rotating machine is rotated and sliding loss occurs with the rotation. Considering this point, the gear ratio is reduced when inertial running is canceled. In this case, the rotational speed of the rotating machine with respect to the engine rotational speed after the inertia traveling cancellation is smaller than that during inertia traveling. Thereby, in the non-inertial running state after cancellation of inertial running, sliding loss accompanying rotation of the rotating machine can be reduced, and accordingly, running due to engine combustion can be suitably performed.

In a thirteenth aspect, the transmission ratio is a ratio of a rotational speed of the rotary shaft of the rotating machine to a rotational speed of the output shaft, and the shift control unit is configured to satisfy the predetermined inertial running condition. The speed ratio is made larger than before, and the speed ratio is made smaller when the engine speed becomes equal to or higher than a predetermined speed as the engine speed is adjusted.

When increasing the engine rotation speed by driving the rotating machine, it is considered that a large torque is not required if the engine rotation speed is in a rotation speed range equal to or higher than a predetermined rotation speed. In consideration of this point, in the above configuration, when the engine rotation speed becomes equal to or higher than the predetermined rotation speed due to the adjustment of the engine rotation speed, the gear ratio is made small. Can be reduced, and as a result, energy consumption accompanying the shift to non-inertial running can be reduced.

In a fourteenth aspect, the regenerative device is a rotating electrical machine that performs regenerative power generation that collects kinetic energy of the vehicle as electric energy, and the regenerative power generation by the rotating electrical machine is performed at a predetermined output or less. When the brake operation is applied during the inertial traveling, a setting unit that sets a duration of the regenerative traveling and a request output for requesting the regenerative traveling, and the duration is a predetermined time or less, And when the said request | requirement output is more than predetermined, the permission part which permits the said regenerative power generation with an output larger than the said predetermined output is provided.

Regenerative power generation by a rotating electrical machine is performed at a predetermined output or less (output is limited) in consideration of heat associated with the power generation operation. For this reason, for example, even when the amount of brake operation is large and the required output for regenerative travel is large, the regenerative energy may not be sufficiently recovered due to the output restriction.

In this regard, in the above configuration, when the brake operation is performed during inertial traveling, when the duration of the regenerative traveling is equal to or shorter than a predetermined time and the required output is equal to or higher than the predetermined output, the output is larger than the predetermined output. Allowed regenerative power generation. For example, when the duration of regenerative travel is extremely short and the required output is large, regenerative power generation with an output larger than a predetermined output is possible. That is, in this case, if the regenerative power generation time is extremely short, the temperature rise of the rotating electrical machine can be suppressed even if the regenerative power generation is performed at or above the output limit. Thereby, the regenerative energy according to the required output can be efficiently recovered while suppressing an excessive temperature rise of the rotating electrical machine.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. The drawing
FIG. 1 is a configuration diagram showing an outline of a vehicle control system, FIG. 2 is an explanatory diagram showing an outline of each traveling state. FIG. 3 is a timing chart when transitioning from the inertia running state to the regenerative running state, FIG. 4 is a flowchart showing the travel control process. FIG. 5 is a correlation diagram showing the relationship between the SOC and the coefficient α. FIG. 6 is a flowchart showing a travel control process in the second embodiment. FIG. 7 is a flowchart showing a regenerative energy estimation process in the third embodiment. FIG. 8 is a correlation diagram showing the relationship between the vehicle speed, the road surface gradient, and the regeneration duration time. FIG. 9 is a configuration diagram showing an outline of the vehicle control system in the fourth embodiment. FIG. 10 is a flowchart showing a processing procedure of shift control in the fourth embodiment. FIG. 11 is a timing chart during inertial running in the fourth embodiment. FIG. 12 is a flowchart showing a processing procedure of regenerative power generation in the fifth embodiment. FIG. 13 is a correlation diagram illustrating the relationship among the brake operation amount, the road surface gradient, and the regeneration request output.

(First embodiment)
Hereinafter, an embodiment embodying the present disclosure will be described with reference to the drawings. In this embodiment, in a vehicle including an engine as a travel drive source, normal travel that travels with the clutch in the power transmission state, coasting travel that travels with the clutch in the power cut-off state (coasting travel), and power for the clutch It is assumed that the regenerative running in which the kinetic energy of the vehicle is regenerated in the transmission state is selectively performed.

In the vehicle 10 shown in FIG. 1, an engine 11 is a multi-cylinder internal combustion engine driven by combustion of fuel such as gasoline or light oil, and appropriately includes a fuel injection valve, an ignition device, and the like as is well known. The engine 11 is integrally provided with an ISG 13 as a generator and an electric motor. A rotating shaft 14 of the ISG 13 is drivingly connected to the engine output shaft 12 by a belt or the like. In this case, the rotation shaft 14 of the ISG 13 is rotated by the rotation of the engine output shaft 12, while the engine output shaft 12 is rotated by the rotation of the rotation shaft 14 of the ISG 13. That is, the ISG 13 has a power generation function for generating power (regenerative power generation) by rotation of the engine output shaft 12 and a power output function for applying a rotational force to the engine output shaft 12. When the engine is started, an initial rotation (cranking rotation) is applied to the engine 11 by the rotation of the ISG 13.

An in-vehicle battery 15 as a storage battery is electrically connected to the ISG 13. In this case, the power is supplied from the battery 15 to drive the ISG 13 and the battery 15 is charged by the generated power of the ISG 13. The electric power of the battery 15 is used to drive various electric loads mounted on the vehicle.

In addition to the ISG 13, an auxiliary device 16 such as a water pump or a fuel pump is mounted on the vehicle 10 as a driven device that is driven by the rotation of the engine output shaft 12. In addition, an air conditioner compressor may be included as the driven device. Driven devices include those directly coupled to the engine output shaft 12 and those coupled to the engine output shaft 12 by the clutch means in addition to those coupled to the engine 11 by a belt or the like. .

A transmission 18 is connected to the engine output shaft 12 via a clutch device 17 having a power transmission function. The clutch device 17 is, for example, a friction clutch, and includes a disk (flywheel or the like) on the engine 11 side connected to the engine output shaft 12 and a disk (clutch disk) on the transmission 18 side connected to the transmission input shaft 21. Etc.) and a set of clutch mechanisms. When both disks come into contact with each other in the clutch device 17, the power is transmitted between the engine 11 and the transmission 18 (clutch connection state), and both the disks are separated from each other. Then, a power cut-off state (clutch cut-off state) is established in which power transmission between the engine 11 and the transmission 18 is cut off. The clutch device 17 of the present embodiment is configured as an automatic clutch that performs switching between a clutch engagement state / clutch disengagement state by an actuator such as a motor. The clutch device 17 may be provided inside the transmission 18.

The transmission 18 is, for example, a continuously variable transmission (CVT) or a multi-stage transmission having a plurality of shift stages. The transmission 18 shifts the motive power of the engine 11 input from the transmission input shaft 21 at a gear ratio according to the vehicle speed V and the engine rotation speed, and outputs it to the transmission output shaft 22.

Wheels 27 are connected to the transmission output shaft 22 via a differential gear 25 and a drive shaft 26 (vehicle drive shaft). Each wheel 27 is provided with a brake device 28 that applies a braking force to each wheel 27 by being driven by a hydraulic circuit (not shown) or the like. The brake device 28 adjusts the braking force for each wheel 27 in accordance with the pressure of a master cylinder (not shown) that transmits the depression force of the brake pedal to the hydraulic oil.

Further, the present system includes an engine ECU 31 that controls the operating state of the engine 11 and a transmission ECU 32 that controls the clutch device 17 and the transmission 18 as on-vehicle control means. Each of these

ECUs

31 and 32 is a well-known electronic control device including a microcomputer or the like, and controls the engine 11, the transmission 18 and the like based on detection results of various sensors provided in this system. Are implemented as appropriate. The

ECUs

31 and 32 are communicably connected to each other, and can share control signals, data signals, and the like. In the present embodiment, the ECU 31 includes two

ECUs

31 and 32, and the engine ECU 31 constitutes a “vehicle control device”. However, the present invention is not limited to this, and two or more ECUs constitute a vehicle control device. May be.

As sensors, an accelerator sensor 41 that detects an operation amount (accelerator operation amount) of an accelerator pedal as an accelerator operation member, and a brake sensor 42 that detects an operation amount (brake operation amount) of a brake pedal as a brake operation member. A vehicle speed sensor 43 for detecting the vehicle speed V, an inclination angle sensor 44 for detecting the inclination angle of the road surface of the vehicle 10, a rotation speed sensor 45 for detecting the engine rotation speed, a battery sensor 46 for detecting the state of the battery 15, and the like. The detection signals of these sensors are sequentially input to the engine ECU 31. In addition, the system is provided with a load sensor (air flow meter, intake pressure sensor) for detecting engine load, a cooling water temperature sensor, an outside air temperature sensor, an atmospheric pressure sensor, and the like, which are not shown.

The engine ECU 31 performs various engine controls such as fuel injection amount control by a fuel injection valve and ignition control by an ignition device based on detection results of various sensors, engine start by ISG 13, engine torque assist and power generation control, brake device Brake control by 28 is performed. Further, the transmission ECU 32 performs intermittent control of the clutch device 17 and shift control of the transmission 18 based on detection results of various sensors.

The vehicle 10 according to the present embodiment has a function of performing inertial running while the clutch device 17 is in a disconnected state under the situation where the vehicle 10 is running by driving the engine 11. Moreover, it has the function to perform the regenerative driving | running | working which makes the clutch apparatus 17 a connection state, collect | recovers kinetic energy. This is intended to improve fuel efficiency.

FIG. 2 is an explanatory diagram showing an outline of each traveling state of the vehicle 10. As each running state,
(1) Normal traveling state (2) Inertial traveling state (3) Regenerative traveling state is defined, and the vehicle 10 shifts to each traveling state as a predetermined condition is established. (1) The normal running state is a state in which the vehicle 10 is caused to travel with the engine 11 in an operating state and the clutch device 17 in a connected state (specifically, a state corresponding to a shift operation position by a driver). (2) The inertia traveling state is a state in which the vehicle 10 is coasted with the engine 11 stopped and the clutch device 17 disconnected. (3) The regenerative travel state is a state in which the engine 11 is in an operating state (no fuel injection), the clutch device 17 is in a connected state, regenerative power generation is performed by the ISG 13, and the vehicle 10 travels.

Here, (1) the transition from the normal traveling state to (2) the inertial traveling state and (2) the transition from the inertial traveling state to (1) the normal traveling state are each performed according to the establishment of known conditions. The For example, when the vehicle 10 is (1) in the normal traveling state, the engine ECU 31 shifts the vehicle 10 to (2) the inertial traveling state in accordance with establishment of predetermined coasting conditions including the accelerator condition and the brake condition. . The predetermined coasting conditions include that the engine rotational speed is stable at a predetermined value or higher (for example, idle rotational speed or higher), the vehicle speed V is within a predetermined range (for example, 20 to 120 km / h), road surface It may be included that the gradient (tilt) is within a predetermined range. On the other hand, when the vehicle 10 is in the (2) inertia traveling state, the engine ECU 31 shifts the vehicle 10 to (1) the normal traveling state in accordance with establishment of predetermined coast release conditions including the accelerator condition and the brake condition. . At this time, the inertial running state may be canceled as the predetermined coast implementation condition is not established.

Further, (1) transition from the normal travel state to (3) regenerative travel state, and (3) transition from the regenerative travel state to (1) normal travel state are each performed according to the establishment of a known condition. . For example, when the vehicle 10 is (1) in the normal running state, the engine ECU 31 (3) in the regenerative running state according to the establishment of predetermined regeneration execution conditions including the brake condition and the storage state of the battery 15. To move to. At this time, regenerative power generation is performed by the ISG 13, and kinetic energy is stored in the battery 15 as electric energy. On the other hand, when the vehicle 10 is in the (3) regenerative travel state, the engine ECU 31 shifts to (1) the normal travel state in accordance with the establishment of a predetermined regenerative release condition including the accelerator condition.

Here, in the present embodiment, (2) the transition from the inertia traveling state to (3) the regenerative traveling state and (3) the transition from the regenerative traveling state to (2) the inertia traveling state can be performed.

(2) The transition from the inertia running state to the (3) regenerative running state will be described in detail. When shifting from inertial running to regenerative running, it is necessary to connect the clutch device 17 that is in the disconnected state. In this case, in order to reduce vibration and noise when the clutch is connected, the rotational speed of the engine output shaft 12 is adjusted according to the rotational speed of the transmission input shaft 21 (that is, the rotational speed corresponding to the vehicle speed V). It is desirable to connect the clutch device 17. In the present embodiment, the engine 11 is started by driving the ISG 13 to increase the engine rotation speed. The driving of the ISG 13 involves energy consumption. Therefore, depending on the embodiment of the regenerative travel, it is considered that the energy (energy consumption) consumed for increasing the engine rotation speed may be larger than the energy recovered by the regenerative travel (regenerative energy). In such a case, it is not preferable from the viewpoint of improving fuel consumption.

The relationship between energy consumption and regenerative energy will be described with reference to FIG. In FIG. 3, when a predetermined brake operation is performed during coasting based on a known coast release condition (for example, when the amount of braking operation is greater than a predetermined threshold Th), It is supposed to shift to regenerative driving. That is, in this case, the brake operation is included in the predetermined regeneration execution condition during inertial running. The brake operation here may be a brake operation by a driver or a deceleration control (automatic brake or the like) by a vehicle operation control unit.

In FIG. 3, before the timing t11, the inertial running is being performed. In this state, the clutch is turned off (disengaged) and the engine 11 is stopped. And if brake operation is implemented at the timing t11, control for transfering to regenerative driving will be implemented. That is, the engine 11 is started by driving the ISG 13 and a rotational force is applied to the engine output shaft 12. As a result, the engine speed increases. When the engine rotational speed corresponding to the vehicle speed V is reached (timing t12), the coasting is switched to regenerative traveling. At this time, the clutch is turned on (connected), and regenerative power generation by the ISG 13 is performed. Thereafter, when the brake operation is released during the regenerative travel (timing t13), the clutch is turned off and the regenerative travel is switched to the inertia travel. Then, when the engine 11 is stopped along with the shift to the inertia traveling, the engine rotation speed converges to zero.

When the brake operation amount increases again at timing t14, the engine 11 is started by driving the ISG 13. Then, the engine speed increases, and the coasting is switched to the regenerative traveling at timing t15. Thereafter, when the brake operation is released during the regenerative travel and the accelerator operation is performed (timing t16), the regenerative travel is switched to the normal travel.

In FIG. 3, the vehicle 10 is in the coasting state before the timing t12 and at the timings t13 to t14, is in the regenerative traveling state at the timings t12 to t13 and the timings t15 to t16, and is in the normal traveling state after the timing t16. .

Here, the energy consumed when shifting to the regenerative traveling at timing t12 to t13 is A1, and the energy recovered by the regenerative traveling at timing t12 to t13 is B1, and when shifting to the regenerative traveling at timing t15 to t16. The consumed energy is A2, and the energy recovered by regenerative travel at timings t15 to t16 is B2. In this case, in the regenerative travel at timings t15 to t16, the regenerative energy B2 is larger than the consumed energy A2, and the fuel efficiency effect by the regenerative travel is obtained. On the other hand, in the regenerative travel at timings t12 to t13, the consumed energy A1 is larger than the regenerative energy B1, and the consumed energy cannot be recovered by the regenerative energy. That is, in the regenerative travel at the timing t12 to t13, energy is lost by shifting from the inertia travel to the regenerative travel, which is considered disadvantageous from the viewpoint of energy efficiency.

Therefore, in the present embodiment, when a braking operation is performed as a predetermined regeneration execution condition during inertial traveling, energy consumption consumed by adjustment (increase) of the engine speed is estimated and recovered by regenerative traveling. The regenerative energy to be estimated is estimated. Then, based on the comparison between the consumed energy and the regenerative energy, the transition from the inertia travel to the regenerative travel is performed. Specifically, when it is determined that the regenerative energy is larger than the consumed energy, the inertial traveling is canceled and the regenerative traveling is performed, and when it is determined that the regenerative energy is smaller than the consumed energy, the inertial traveling is maintained. . That is, the transition from the inertia traveling to the regenerative traveling is enabled, and the transition to the disadvantageous regenerative traveling from the viewpoint of energy efficiency is suppressed.

The aspect of this embodiment will be described with reference to FIG. At timing t11 when the brake operation is performed during inertial running, the engine ECU 31 estimates the consumed energy A1 and the regenerative energy B1. If it is determined that the consumed energy A1 is larger than the regenerative energy B1, the inertia traveling is maintained without shifting from the inertia traveling to the regeneration traveling. In other words, in this case, the clutch is kept off (disengaged) at timings t12 to t13, and neither energy consumption A1 nor regenerative energy B1 is generated. On the other hand, at the timing t14, it is determined that the regenerative energy B2 is larger than the consumed energy A2, and at the timing t15, the inertia traveling is switched to the regenerative traveling. As described above, in the present embodiment, the regenerative travel at the timings t12 to t13, which is disadvantageous from the viewpoint of energy efficiency, is not performed in FIG. 3, but the regenerative travel at the advantageous timings t15 to t16 is performed.

The engine ECU 31 estimates the energy consumption Erec and the regenerative energy Eregen, respectively, when a brake operation is performed during inertial running.

In the present embodiment, the energy consumption Erec refers to the energy required to rotate the engine output shaft 12 by the ISG 13. Specifically, the energy consumption Erec is estimated based on the sum of the required rotational energy calculated from the vehicle speed V and the loss energy including friction loss. More specifically, it is estimated based on the following formula (1).

The definition of each symbol in the above formula (1) will be briefly described. j represents the inertia (moment of inertia) of the engine 11, ωt represents the target rotational speed of the engine 11, ω0 represents the current engine rotational speed, Ploss represents the loss output, Tst represents the return target time, Effmot Represents the output efficiency in the power running drive of the ISG 13, and Effbatt_out represents the output efficiency of the battery 15. The loss output is engine friction or the like and can be calculated by a known method.

Here, ωt is calculated based on the vehicle speed V. In this case, ωt is calculated as a larger value as the vehicle speed V increases. On the other hand, since the engine 11 is stopped during coasting, ω0 is considered to be zero in many cases. Further, it is considered that other parameters do not fluctuate greatly in each coasting. Then, it is considered that the energy consumption Erec greatly depends on the vehicle speed V.

Further, the engine ECU 31 estimates the regenerative energy Eregen. In the present embodiment, regenerative energy Eregen refers to energy that can be recovered by regenerative travel. Specifically, the regenerative energy Eregen is estimated using a regenerative output Pregen calculated based on the brake operation amount and a regenerative duration Tgen that is predicted to continue regenerative travel. More specifically, it is estimated based on the following formula (2).

The definition of each symbol in the above formula (2) will be briefly described. Effgen represents the output efficiency in the power generation of the ISG 13, and Effbatt_in represents the input efficiency of the battery 15. Here, the regeneration continuation time Tgen is a predetermined value determined in advance by adaptation or the like, and is, for example, 10 seconds.

Then, the engine ECU 31 controls the transition from inertial running to regenerative running by comparing the estimated energy consumption Erec and regenerative energy Eregen, respectively.

Next, the traveling control process of the vehicle control device according to the present disclosure will be described with reference to the flowchart of FIG. This process is repeatedly performed by the engine ECU 31 at a predetermined cycle.

4, in step S11, it is determined whether or not the vehicle 10 is currently in an inertia running state with the clutch off. If YES, the process proceeds to step S12, and if NO, the process proceeds to step S21. In step S12, it is determined whether or not the brake is on. Whether or not the brake is on is determined based on, for example, that the amount of brake operation detected by the brake sensor 42 is greater than zero. If step S12 is YES, the process proceeds to step S13.

In step S13, energy consumption Erec is estimated. The consumed energy Erec is estimated based on the above-described equation (1), for example. In step S14, the regenerative energy Eregen is estimated. The regenerative energy Eregen is estimated based on the above-described equation (2), for example. In step S15, it is determined whether or not the estimated regenerative energy Eregen is larger than the consumed energy Erec. When step S15 is YES, that is, when the regenerative energy Eregen is larger than the consumed energy Erec, the inertia traveling is canceled and the transition to the regenerative traveling is performed (step S16). If step S15 is NO, that is, if the consumed energy Erec is larger than the regenerative energy Eregen, coasting is maintained (step S17).

On the other hand, when step S12 is NO, it progresses to step S18 and it is determined whether it is in the accelerator-on state. Whether or not the accelerator is on is determined based on, for example, that the accelerator operation amount detected by the accelerator sensor 41 is greater than zero. If step S18 is YES, the inertia traveling is canceled and the transition to the normal traveling is performed (step S19). If step S18 is NO, this process is ended as it is. That is, the vehicle 10 maintains the coasting state.

In step S21, it is determined whether or not the vehicle 10 is currently in a regenerative running state. If YES, the process proceeds to step S22. If NO, the process is terminated. In step S22, it is determined whether or not the accelerator is on. When step S22 is YES, that is, when the accelerator is turned on during the regenerative travel, the regenerative travel is canceled and the shift to the normal travel is performed (step S23).

On the other hand, when step S22 is NO, it progresses to step S24, and it is determined whether it is in a brake-off state. The brake-off state is determined based on, for example, that the brake operation amount detected by the brake sensor 42 is zero. In step S24, in addition to the brake off state, for example, the SOC of the battery 15 is equal to or higher than a predetermined value (for example, a value close to full charge), or the vehicle speed V is equal to or lower than a predetermined value (for example, 30 km / h). The following may be determined. If step S24 is YES, a transition from regenerative travel to inertial travel is performed (step S25). If step S24 is NO, this process is ended as it is. That is, the vehicle 10 maintains the regenerative travel state.

Steps S13 and S14 correspond to an “estimator”, step S15 corresponds to a “determination unit”, and steps S16 and S17 correspond to a “travel controller”.

As described above, when shifting from inertial running to regenerative running, energy consumption Erec is required as the engine speed increases (adjusts). On the other hand, when shifting from regenerative travel to inertial travel, energy consumption Erec is not required. That is, the conditions for transition between inertial running and regenerative running are different. Note that the energy consumption Erec is also required when shifting from inertial traveling to normal traveling.

According to the embodiment described above in detail, the following excellent effects can be obtained.

In the above configuration, when a braking operation is performed as a regeneration execution condition during inertial traveling, the energy consumption Erec consumed by adjusting the engine speed is estimated, and the regenerative energy Eregen recovered by the regenerative traveling is estimated. To do. Then, based on the comparison between the consumed energy Erec and the regenerative energy Eregen, the transition from the inertia traveling to the regenerative traveling is performed. Specifically, when it is determined that the regenerative energy Eregen is larger than the consumed energy Erec, the transition from the inertia traveling to the regenerative traveling is performed. Therefore, the energy exceeding the consumed energy Erec can be recovered by the regenerative traveling. In addition, coasting is maintained when it is determined that the regenerative energy Eregen is smaller than the energy consumption Erec, so that the fuel efficiency effect by coasting can be obtained, and the shift to unfavorable regeneration from the viewpoint of energy efficiency can be achieved. Can be suppressed. Furthermore, the frequency of switching from coasting to regenerative driving can be suppressed, leading to improved drivability. Thereby, inertial running and regenerative running can be switched appropriately.

The consumed energy Erec is energy required for rotating the engine output shaft 12 to the target engine speed, and is considered to correlate with the vehicle speed V. That is, when the vehicle speed V is high, the target engine speed increases, and the energy consumption Erec increases accordingly. In consideration of this point, the energy consumption Erec is estimated based on the vehicle speed V, so that the energy consumption Erec can be estimated with high accuracy. As a result, it is possible to appropriately determine the transition from inertial travel to regenerative travel.

Regenerative energy Eregen is considered to correlate with the amount of brake operation. For example, when the brake operation amount is large, the driver's request for deceleration is large, and the regenerative energy Eregen is also large. Considering this point, the regenerative energy Eregen is estimated based on the brake operation amount, so that the regenerative energy Eregen can be estimated with high accuracy. As a result, it is possible to appropriately determine the transition from inertial travel to regenerative travel.

(Modification of the first embodiment)
In the above embodiment, the engine 11 is stopped during inertial running, but this may be changed. For example, the engine rotation speed may be maintained at an idle rotation speed (for example, 700 rpm) without stopping the engine 11 during inertial traveling. In such a configuration, the range in which the engine rotation speed is increased by driving the ISG 13 is smaller than the configuration in which the engine 11 is stopped. Therefore, energy consumption Erec when shifting from inertial traveling to regenerative traveling is reduced. Further, since the engine rotation speed is maintained at the idle rotation speed, the responsiveness at the time of releasing the inertial running is improved as compared with the case where the engine 11 is stopped.

∙ When the brake operation is performed during coasting, the engine rotation speed may be adjusted by means other than driving the ISG 13. For example, the engine rotation speed is adjusted by the operation (combustion) of the engine 11. In this case, the energy required for operating the engine 11 may be estimated as the consumed energy Erec.

Further, a configuration in which the engine rotation speed is increased by combining the driving of the ISG 13 and the combustion of the engine 11 may be employed. Here, when the engine rotation speed is increased, the combustion efficiency of the engine 11 is poor in the low rotation speed region, so that the driving by the ISG 13 is considered to be more efficient than the combustion of the engine 11. On the other hand, in the high rotation speed region, the combustion efficiency of the engine 11 is good. Considering this point, it is preferable to select driving of the ISG 13 and combustion of the engine 11 according to the engine rotation speed. For example, in a low rotational speed range where the engine rotational speed is less than a predetermined value K, the engine rotational speed is increased by driving the ISG 13, and in a high rotational speed range where the engine rotational speed is equal to or higher than the predetermined value K, combustion of the engine 11 occurs. It is good to increase the engine speed. The predetermined value K is, for example, an idle rotation speed. In this case, for example, if the energy consumption Erec is estimated as energy consumed by driving the ISG 13, the energy consumption Erec when shifting from inertia traveling to regenerative traveling is reduced.

The engine rotation speed may be increased by a combination of a starter (not shown) and the combustion of the engine 11 instead of the combination of the drive of the ISG 13 and the combustion of the engine 11.

In the above embodiment, the ISG 13 is used as the regeneration device, but the regeneration device is not limited to this. For example, an alternator having only a power generation function may be used as the regeneration device, and a flywheel may be used as the regeneration device. In the latter case, the kinetic energy of the vehicle 10 is stored as rotational energy in the flywheel. At this time, a starter may be used as a device for starting the engine 11.

(Second Embodiment)
In the second embodiment, when the regenerative energy Eregen is estimated, the SOC is acquired as a parameter indicating the storage state of the battery 15, and the regenerative energy Eregen estimated based on the SOC is corrected.

For example, even if the transition from inertial travel to regenerative travel is possible, it is conceivable that the recovery of regenerative energy Eregen is limited depending on the SOC of the battery 15. For example, when the SOC of the battery 15 is close to full charge, the power that can be charged to the battery 15 is small, and even if regenerative power generation is performed, the regenerative energy Eregen that is recovered may be limited. is there.

Therefore, when the regenerative energy Eregen is estimated, the engine ECU 31 acquires the SOC of the battery 15 and corrects the regenerative energy Eregen estimated based on the SOC. Then, the regenerated energy Eregen after correction is used to compare with the consumed energy Erec. With regard to the correction, for example, when the SOC of the battery 15 is close to full charge, the electric energy that can be charged in the battery 15 becomes small, so that the estimated regenerative energy Eregen is corrected to be reduced. Although the correction method is not particularly limited, for example, there is a method of multiplying the estimated regenerative energy Eregen by a coefficient α. In this case, the SOC within the usage range of the battery 15 and the coefficient α (value of 0 or more and 1 or less) have a correlation as shown in FIG. 5, for example. In FIG. 5, the coefficient α is 1 when the SOC is equal to or less than the predetermined value P. In such a case, the regenerative energy Eregen does not change before and after the correction. On the other hand, when the SOC is equal to or greater than the predetermined value P, the coefficient α decreases as the SOC increases.

FIG. 6 is a flowchart showing a processing procedure of the travel control process in the second embodiment, and this process is repeatedly performed by the engine ECU 31 at a predetermined period in place of FIG. 4 described above. In FIG. 6, the same processes as those in FIG. The changes from the process of FIG. 4 are the addition of steps S31 and S32 and the change of the processing content of step S15.

In FIG. 6, when the vehicle 10 is coasting and the brake is on (when both steps S11 and S12 are YES), the consumed energy Erec is estimated (step S13), and the regenerative energy Eregen is estimated. Is estimated (step S14). In subsequent step S31, the engine ECU 31 acquires the SOC of the battery 15. In step S32, the regenerative energy Eregen is corrected based on the acquired SOC. Specifically, the regenerative energy Eregen is corrected based on the above-described correlation between the SOC and the coefficient α.

In step S15, it is determined whether the corrected regenerative energy Eregen is larger than the consumed energy Erec. If step S15 is YES, it will progress to step S16 and will transfer to regeneration driving | running | working. If step S15 is NO, it will progress to step S17 and will maintain inertial running. Step S32 corresponds to a “correction unit”.

In the above configuration, since the regenerative energy Eregen is corrected based on the SOC of the battery 15, in addition to the energy balance between the consumed energy Erec and the regenerative energy Eregen, the state on the side where the regenerative energy Eregen is stored can be considered. The transition to the regenerative travel that is disadvantageous from the viewpoint of energy efficiency can be suitably suppressed.

(Modification of the second embodiment)
In the second embodiment, the regenerative energy Eregen is corrected based on the SOC of the battery 15. However, the regenerative energy Eregen may be corrected based on other parameters indicating the state of the battery 15. For example, the regenerative energy Eregen may be corrected based on the temperature of the battery 15.

Further, the regenerative energy Eregen may be corrected based on a parameter indicating the state of the ISG 13. That is, in this case, the regenerative energy Eregen is corrected in consideration of the state on the energy recovery side. For example, in the configuration in which the regenerative energy Eregen is corrected based on the temperature of the ISG 13, the temperature of the ISG 13 (for example, the temperature of the switching element of the inverter unit or the temperature of the stator of the motor unit) is acquired in step S31 in FIG. In step S32, the regenerative energy Eregen is corrected based on the temperature. Even when the transition from inertial travel to regenerative travel is possible, it is considered that regenerative power generation is limited when the temperature of the ISG 13 is equal to or higher than a predetermined value. In consideration of this point, by correcting the regenerative energy Eregen based on the temperature of the ISG 13, in addition to the energy balance, it is possible to take into account the state of the energy recovery side, and to a disadvantageous regenerative running from the viewpoint of energy efficiency Can be suitably suppressed.

In the second embodiment, the method of multiplying the coefficient α is used as a method for correcting the regenerative energy Eregen, but the present invention is not limited to this. For example, the battery acceptable energy is calculated based on the SOC of the battery 15 and the battery capacity, and a smaller value of the calculated battery acceptable energy and the estimated regenerative energy Eregen is used as the corrected regenerative energy Eregen. Good.

In the second embodiment, the regenerative energy Eregen is corrected based on the SOC. However, for example, when the SOC is a predetermined value or more, the transition from inertial running to regenerative running may be prohibited. In such a configuration, the predetermined value is set to, for example, an SOC close to full charge. In addition, based on a parameter indicating the state of the battery 15 such as the temperature of the battery 15 or a parameter indicating the state of the ISG 13, a transition from inertia traveling to regenerative traveling may be prohibited. In the latter case, for example, when the temperature of the ISG 13 (for example, the temperature of the switching element of the inverter unit or the temperature of the stator of the motor unit) is equal to or higher than a predetermined value, the transition to the regenerative traveling is prohibited and the inertia traveling is maintained. You may make it do.

(Third embodiment)
In the said 1st Embodiment, it was set as the structure which uses the predetermined value predetermined as regeneration continuation time Tgen. Here, since the vehicle traveling tendency varies depending on the vehicle 10 and the driver, the duration of the regenerative traveling is considered to be different due to the tendency. Furthermore, since the traveling conditions differ depending on the regenerative traveling, it is considered that the duration of the regenerative traveling is different due to this.

Therefore, in the third embodiment, when a brake operation is performed during inertial traveling, the past duration is acquired according to the traveling condition of the vehicle 10, and the current duration (regeneration is based on the duration). Set the duration (Tgen). Then, the regeneration energy Eregen is estimated using the set regeneration duration Tgen.

The engine ECU 31 stores the duration of regenerative travel as a history in a memory or the like in the engine ECU 31 for each travel condition in each regenerative travel in the past. The traveling conditions include, for example, vehicle speed V, road surface gradient, and the like. In this case, it is considered that the longer the vehicle speed V is, the longer the duration of regenerative travel is. In addition, it is considered that the longer the road gradient, the longer the duration of regenerative travel.

FIG. 7 describes the processing procedure for estimating the regenerative energy Eregen in step S14 of FIG. This process is performed by the engine ECU 31 as a subroutine process when step S14 of FIG. 4 is performed. That is, in FIG. 4, when the vehicle 10 is in an inertia running state and the brake is on (when both steps S11 and S12 are YES), the consumed energy Erec is estimated (step S13). Then, the process proceeds to step S101 in FIG.

In step S101, the traveling condition of the vehicle 10 is acquired. For example, the vehicle speed V is acquired based on the detection value by the vehicle speed sensor 43, and the road surface gradient is acquired based on the detection value by the inclination angle sensor 44. In step S102, the duration of past regenerative travel is acquired according to the acquired travel conditions. For example, the duration of regenerative travel that has been performed in the past at a vehicle speed V that is approximately the same as the current vehicle speed V is acquired. In addition, you may consider a road surface gradient. In step S103, the current regeneration duration Tgen is set based on the obtained duration. Here, for example, the average value of the duration of regenerative travel for the past 10 times under the same travel conditions is set as the regeneration duration Tgen. In step S104, the regenerative energy Eregen is estimated based on the set regeneration continuation time Tgen, and the process returns to step S15 in FIG. In the present embodiment, step S103 corresponds to a “setting unit”, and step S104 corresponds to an “estimating unit”.

Regenerative energy Eregen is considered to correlate with the duration of regenerative travel. Considering this point, in the above configuration, when the brake operation is performed during inertial driving, the regeneration duration Tgen is set as the current duration, and based on the set regeneration duration Tgen and the brake operation amount. Therefore, the regenerative energy Eregen can be estimated with high accuracy.

In addition, when the regenerative travel is performed, the duration time is stored each time, and the regeneration duration time Tgen is set based on the stored history of the continuous time. Therefore, according to the tendency of the regenerative travel for each vehicle 10. The regeneration duration Tgen can be set appropriately. Furthermore, since the history of the past duration is acquired according to the driving conditions of the vehicle 10 and the regeneration duration Tgen is set based on the history, the conditions affecting the duration of the regeneration running are taken into account. The regeneration duration Tgen can be set. As a result, the regeneration continuation time Tgen can be appropriately set according to the operating conditions at each time, and as a result, the regenerative energy Eregen can be estimated with high accuracy.

(Modification of the third embodiment)
In the third embodiment, the regeneration duration Tgen is set based on the past regeneration travel duration stored in a memory or the like. However, this may be changed. For example, the regeneration duration Tgen may be set each time based on the traveling conditions of the vehicle 10. In such a configuration, for example, a correlation map as shown in FIG. 8 can be used. In FIG. 8, the regeneration duration Tgen is longer as the vehicle speed V is higher, and the regeneration duration Tgen is longer as the road gradient is steeper. Alternatively, the regeneration duration time Tgen may be set using traffic information such as traffic lights and traffic congestion on the road. In this case, for example, if the traffic light that exists in the traveling direction of the vehicle 10 is a red signal, the vehicle 10 needs to stop, so the regeneration duration Tgen is set short.

(Fourth embodiment)
Next, the fourth embodiment will be described focusing on the differences from the first embodiment. In FIG. 9, schematic structure of the vehicle control system in 4th Embodiment is shown. The fourth embodiment is directed to a vehicle control system including a transmission 51 between the engine output shaft 12 and the rotating shaft 14 of the ISG 13. The transmission 51 can change the speed ratio of the rotational power by the ISG 13 (the rotational speed of the rotary shaft 14 / the rotational speed of the engine output shaft 12). Here, if the rotation speed of the engine output shaft 12 is N1 and the rotation speed of the rotation shaft 14 is N2, the gear ratio is N2 / N1. The engine ECU 31 controls the gear ratio of the transmission 51 according to the state of the vehicle 10. Except that this transmission 51 is provided, it is the same as the configuration diagram of FIG.

In the first embodiment, the control when shifting from (2) the inertia running state to (3) the regenerative running state is shown in FIG. 2, but in the fourth embodiment, (2) in the inertia running state, in particular. The control will be described. When the vehicle 10 shifts to coasting, the engine 11 is stopped and the engine speed decreases as time passes.

In the fourth embodiment, in inertial running, the gear ratio of the transmission 51 is changed to a side that suppresses the decrease in engine rotation speed. Specifically, when the vehicle 10 is in a normal running state and a predetermined coasting condition is satisfied, the gear ratio (the rotational speed of the rotary shaft 14 / the rotational speed of the engine output shaft 12) is set to be higher than the previous gear ratio. Enlarge. Then, the vehicle 10 is switched to coasting with the gear ratio increased, and coasting is performed. Then, the gear ratio is reduced when shifting from inertia traveling to normal traveling. That is, the increased gear ratio is restored.

In this case, by increasing the gear ratio before shifting to inertial running, the kinetic energy at the time of deceleration can be recovered as rotational energy by the ISG 13, and after recovering, it is possible to shift to inertial driving. As a result, the inertia of the engine 11 during inertial traveling is increased, a decrease in engine rotation speed during inertial traveling is suppressed, and the period during which the engine output shaft 12 rotates during inertial traveling can be extended. As a result, for example, when inertial running is released in a short time, the rotation of the engine output shaft 12 is ensured to reduce the energy consumption Erec associated with the transition. Here, the transition between the normal traveling and the inertia traveling is shown, but the same applies to the transition between the regenerative traveling and the inertia traveling.

The processing procedure of the shift control of the transmission 51 by the engine ECU 31 will be described with reference to the flowchart of FIG. This process is repeatedly performed by the engine ECU 31 at a predetermined cycle.

In step S41, it is determined whether or not the vehicle 10 is currently in the non-inertial traveling state (normal traveling state or regenerative traveling state). If step S41 is YES, the process proceeds to step S42, and if step S41 is NO, the process proceeds to step S46. In step S42, it is determined whether or not the coast execution condition is satisfied. For example, regarding the transition from normal travel to inertial travel, it is determined that the accelerator is off and the brake is off. If step S42 is YES, it will progress to step S43, and if step S42 is NO, this process will be complete | finished as it is.

In step S43, the gear ratio of the transmission 51 is increased. Specifically, the gear ratio is changed so that the rotation speed of the rotation shaft 14 of the ISG 13 is larger than the rotation speed of the engine output shaft 12. In step S44, it is determined whether or not a predetermined time T has elapsed since the gear ratio of the transmission 51 was changed. While this predetermined time T elapses, the kinetic energy is recovered as rotational energy by the ISG 13. Then, when the predetermined time T has elapsed (S44: YES), the process proceeds to step S45, where the clutch is turned off (disengaged) and the vehicle shifts to coasting.

When the vehicle 10 shifts to the inertial running state and step S46 is affirmed, the process proceeds to step S47. In step S47, it is determined whether a coast release condition is satisfied. For example, regarding the transition to normal travel, it is determined whether or not the accelerator is turned on. Regarding the transition to regenerative travel, it is determined whether the brake is turned on and the regenerative energy Eregen is greater than the consumed energy Erec. If step S47 is YES, it will progress to step S48 and will start drive of ISG13.

In the subsequent step S49, it is determined whether or not it is a transition timing to normal driving or regenerative driving. Specifically, the engine ECU 31 determines whether or not the engine rotational speed has increased to a rotational speed corresponding to the vehicle speed V by driving the ISG 13. If it is determined that it is the transition timing (step S49: YES), the process proceeds to step S50. In step S50, the transmission ratio of the transmission 51 is reduced. That is, the gear ratio is returned to the state before the coast execution condition is established. In step S51, inertial running is canceled and the routine proceeds to normal running or regenerative running. On the other hand, if step S46 and step S47 are NO, this process will be complete | finished as it is. Steps S43 and S50 correspond to a “shift control unit”.

Subsequently, FIG. 11 shows a timing chart showing the processing of FIG. 10 more specifically. Here, reference control (control that does not change the transmission ratio of the transmission 51) and control in this embodiment (control that changes the transmission ratio of the transmission 51) are shown. In FIG. Thus, the control in this embodiment is indicated by a solid line. FIG. 11 shows a scene in which the vehicle 10 shifts from the normal driving state to the inertial driving state and then shifts from the inertial driving state to the regenerative driving state.

First, reference control will be described. In this control, the transmission gear ratio of the transmission 51 remains constant regardless of the running state. Prior to timing t21, a state in which normal traveling is being performed is shown, and in this state, the clutch is turned on (connected). When the coast execution condition is satisfied at timing t21, the clutch is turned off (disengaged), and the normal traveling is switched to the inertia traveling. Then, the engine rotation speed decreases as the engine 11 stops, and the engine rotation speed becomes zero at timing t23. Thereafter, when the regeneration execution condition is satisfied at timing t24, the driving of the ISG 13 is started, and the engine rotation speed is increased. Thereafter, the coasting is switched to the regenerative traveling at timing t25. In this reference control, it is necessary to increase the engine speed by ΔNE1 when shifting to regenerative travel.

In contrast, in the control according to the present embodiment, the transmission gear ratio of the transmission 51 is changed from LOW to HIGH at the timing t21 when the coast execution condition is satisfied. That is, in this case, the gear ratio is made larger than the gear ratio in the reference control. Then, the kinetic energy is recovered, and at a timing t22 after a predetermined time T has elapsed, the clutch is turned off and switched to inertial running. That is, in this case, the predetermined time T is a delay time from the establishment of the coast execution condition until the coasting is actually started. Thereafter, the engine rotation speed decreases, but the decrease speed becomes slower than that in the reference control. When the regeneration execution condition is satisfied at timing t24, the driving of the ISG 13 is started, and the inertia traveling is switched to the regeneration traveling at timing t25. In the control in this embodiment, it is necessary to increase the engine rotational speed by ΔNE2 when shifting to regenerative travel.

Here, in the control according to the present embodiment, the range of increase in the engine rotation speed by driving the ISG 13 is smaller than that in the reference control (ΔNE2 <ΔNE1). That is, by increasing the gear ratio in inertia traveling, it is possible to reduce the energy consumption Erec when shifting from inertia traveling to non-inert inertia traveling.

In the above configuration, the gear ratio was changed to the side that suppresses the decrease in engine speed during inertial running. Specifically, the gear ratio is changed from LOW to HIGH when the coast execution condition is satisfied, and coasting is performed in the state of HIGH. In this case, by setting the gear ratio to HIGH, it is possible to suppress a decrease in the engine rotation speed as compared with a case where coasting is performed with LOW. Thereby, the period during which the engine output shaft 12 rotates can be extended, and as a result, it is possible to reduce the energy consumption Erec when shifting from inertia traveling to non-inert inertia traveling.

When traveling by the combustion of the engine 11, the ISG 13 is rotated, and a sliding loss occurs with the rotation. Considering this point, when the inertia traveling is canceled, that is, when the transition from the inertia traveling to the non-inert inertia traveling (normal traveling and regenerative traveling) is performed, the gear ratio is changed from HIGH to LOW. In this case, the rotational speed of the ISG 13 with respect to the engine rotational speed in non-inertial travel is smaller than that during inertial travel. Thereby, the sliding loss accompanying the rotation of the ISG 13 can be reduced in the non-inertial traveling, and accordingly the traveling by the combustion of the engine 11 can be suitably performed. Further, in the configuration in which the cooling fan is drivingly connected to the rotating shaft 14 of the ISG 13, the rotation speed of the ISG 13 is reduced, so that the rotation sound of the cooling fan can be reduced.

(Modification of the fourth embodiment)
In the fourth embodiment, the gear ratio is reduced when releasing the inertia running (the state before the coast execution condition is satisfied), but the timing for reducing the gear ratio is not limited to this. For example, the gear ratio may be reduced when the engine rotation speed reaches a predetermined threshold value NEth during a period in which the engine rotation speed is increased by driving the ISG 13 at the time of transition from inertial running to regenerative running.

In this case, for example, a step of determining whether or not the engine speed is equal to or higher than the threshold NEth is provided as a step that proceeds when step S49 of FIG. 10 is NO. If the engine speed is equal to or higher than the threshold value NEth, the process proceeds to step S50, and the gear ratio is reduced. That is, the gear ratio is reduced before the inertia running is released. On the other hand, if the engine speed is less than the threshold value NEth, the present process is terminated as it is. The threshold value NEth is set to a value larger than the engine rotation speed range where a large torque (passing torque) at the time of starting the engine is required. According to this configuration, the sliding loss of the ISG 13 can be reduced before the inertia traveling is canceled by reducing the gear ratio at a timing when a large torque is not required at the time of starting the engine. It is possible to reduce the energy consumption Erec associated with the transition to.

In the fourth embodiment, the transmission 51 is provided between the engine output shaft 12 and the rotating shaft 14 of the ISG 13. However, the present invention is limited to this as long as the gear ratio of the rotational power by the ISG 13 is variable. Not. For example, it is good also as a structure which provides a speed change function to ISG13 and changes a gear ratio by ISG13.

In the fourth embodiment, instead of the ISG 13, for example, an alternator having only a power generation function or a rotating machine (flywheel or the like) having no power generation function may be used. In such a configuration, a transmission is provided between the engine output shaft 12 and a rotation shaft such as an alternator, and the gear ratio of the transmission is changed to a side that suppresses a decrease in engine rotation speed during inertial running.

(Fifth embodiment)
When performing regenerative power generation, the engine ECU 31 transmits a power generation command to the ISG 13. At this time, the engine ECU 31 sets the regeneration request output based on the brake operation amount, the storage state of the battery 15, and the like. Then, based on the regeneration request output, the ISG 13 is caused to perform regenerative power generation. Thereby, the electric power according to the state of the vehicle 10 is obtained by regenerative power generation.

On the other hand, in order to prevent the temperature of the ISG 13 from excessively rising due to the power generation operation of the regenerative power generation, an output limit may be provided for the regenerative power generation of the ISG 13. Therefore, even when the regenerative request output is large, regenerative power generation may be suppressed to a predetermined output value Wth or less due to the output limitation, and in this case, recovery of the regenerative energy Eregen is limited. The output limit of regenerative power generation is set in consideration of the duration of regenerative travel, and is set assuming regenerative travel of about 30 seconds, for example.

In this embodiment, the engine ECU 31 sets the regeneration duration Tgen and the regeneration request output when the regeneration execution condition is satisfied. And if regeneration continuation time Tgen is below predetermined threshold TA and regeneration required output is above predetermined threshold WA, regenerative power generation with an output larger than output value Wth is permitted. Here, the threshold value TA is a determination value for determining regenerative travel for an extremely short time, and is set to 3 seconds, for example. The threshold value WA is set to a value corresponding to the output limit of regenerative power generation. That is, in this case, regenerative power generation with a large output (output exceeding the output limit of regenerative power generation) is performed in an extremely short time. Thereby, the regenerative energy Eregen can be efficiently recovered.

The processing procedure of regenerative power generation by the engine ECU 31 will be described with reference to the flowchart of FIG. This process is repeatedly performed by the engine ECU 31 at a predetermined cycle.

In step S61, it is determined whether or not the vehicle 10 is currently in a non-regenerative traveling state (normal traveling state or inertial traveling state). If step S61 is YES, the process proceeds to step S62. If step S61 is NO, the process is terminated. In step S62, it is determined whether or not a regeneration execution condition is satisfied. For example, regarding the transition from inertial running to regenerative running, it is determined whether the brake is turned on and the regenerative energy Eregen is greater than the consumed energy Erec. If step S62 is YES, the process proceeds to step S63, and if step S62 is NO, the process ends.

In step S63, the regeneration duration Tgen is set. For example, the regeneration continuation time Tgen is set in the same manner as the process of step S103 in FIG. In a succeeding step S64, a regeneration request output is set. For example, the regeneration request output is set by applying the brake operation amount and the road surface gradient to the map shown in FIG. In the map of FIG. 13, the regeneration request output increases as the brake operation amount increases, and the regeneration request output increases as the road surface gradient increases. The road surface gradient is acquired by the inclination angle sensor 44, GPS information, a gyro sensor (not shown), or the like. Steps S63 and S64 correspond to a “setting unit”.

In step S65, it is determined whether or not the regeneration continuation time Tgen is equal to or less than the threshold value TA and the regeneration request output is equal to or greater than the threshold value WA. If step S65 is NO, it will progress to step S66 and will implement regenerative power generation below the output value Wth. That is, in this case, regenerative power generation is performed within the range of the normal output limit. On the other hand, if step S65 is YES, the process proceeds to step S67, and regenerative power generation with an output larger than the output value Wth is permitted. Specifically, the engine ECU 31 transmits a power generation command to the ISG 13 to generate power with an output larger than Wth, and regenerative power generation is performed. Step S67 corresponds to a “permission unit”.

Further, when regenerative power generation is performed by the ISG 13, excitation of the rotor of the motor unit of the ISG 13 is started based on a power generation command from the engine ECU 31, and regenerative power generation is performed after the excitation is completed. That is, it takes time to complete the excitation of the rotor, and when regenerative power generation is performed in an extremely short time, the time required for this excitation greatly affects the power generation efficiency.

Therefore, in order to efficiently perform regenerative power generation in an extremely short time, the engine ECU 31 may cause the ISG 13 to start a preparatory operation for regenerative power generation before the regenerative execution condition is satisfied. Specifically, when the amount of brake operation becomes equal to or greater than the threshold value Th1, the engine ECU 31 causes the ISG 13 to start exciting the rotor. In this configuration, the regeneration operation condition is set such that the brake operation amount is equal to or greater than the threshold Th2, and the magnitude relationship between the threshold Th1 and the threshold Th2 is Th1 <Th2. Therefore, the brake operation is performed in the non-regenerative running state, and when the brake operation amount becomes equal to or greater than the threshold value Th1, the excitation of the rotor is first started, and when the brake operation amount becomes equal to or greater than the threshold value Th2, regenerative power generation is performed. In other words, according to this configuration, the excitation of the rotor is started before the power generation command by the engine ECU 31 so that the regenerative power generation is performed quickly, and the regenerative energy Eregen can be efficiently obtained even in an extremely short time regenerative power generation. It can be recovered.

In the above configuration, when the regenerative execution condition is satisfied, regenerative power generation with an output larger than the output value Wth is permitted when the regenerative duration Tgen is equal to or smaller than the threshold TA and the regenerative request output is equal to or greater than the threshold WA. I did it. For example, when the regeneration continuation time Tgen is extremely short and the regeneration request output is large, regenerative power generation with an output larger than the output value Wth is possible. In this case, if the time for regenerative power generation is extremely short, even if regenerative power generation is performed at an output limit or more, an increase in temperature of the ISG 13 can be suppressed. Thereby, the regenerative energy Eregen corresponding to the regenerative request output can be efficiently recovered while suppressing an excessive temperature rise of the ISG 13.

(Modification)
In the above-described embodiment, the ISG 13 in which the generator and the motor are integrated as the regenerative device is provided, but an alternator (generator) as the regenerative device and an electric motor that applies a rotational force to the engine output shaft 12 are provided. It is good also as a structure.

Although the present disclosure has been described based on the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

Claims

An engine (11) as a travel drive source, a clutch device (17) provided in a power transmission path connected to the output shaft (12) of the engine, and a regenerative device (which collects kinetic energy of the vehicle via the output shaft) 13) and a vehicle (10) comprising:
In response to the establishment of predetermined inertial running conditions, the clutch device is disengaged to perform inertial running of the vehicle, and in accordance with the establishment of predetermined regeneration execution conditions during inertial running, the engine rotation speed is adjusted. A travel control unit that performs connection to the regenerative travel using the regenerative device from the inertia travel by performing connection of the clutch device;
In the case where a braking operation is performed as the regeneration execution condition during the inertia traveling, an estimation is performed for estimating the energy consumed by adjusting the engine rotation speed and estimating the regeneration energy recovered by the regeneration traveling. And
With
The travel control unit is a vehicle control device that performs a transition from the inertia travel to the regenerative travel based on a comparison between the consumed energy and the regenerative energy.
A determination unit that determines that the regenerative energy estimated by the estimation unit is greater than the consumed energy;
When the regenerative energy is determined to be greater than the consumed energy, the travel control unit performs a transition from the inertia travel to the regenerative travel, and the regenerative energy is determined to be smaller than the consumed energy. The vehicle control device according to claim 1, wherein the inertia running is maintained in a case.
The vehicle control device according to claim 1 or 2, wherein the estimation unit estimates the energy consumption based on a vehicle speed of the vehicle when a braking operation is performed as the regeneration execution condition during the inertia traveling.
The said estimation part, When the brake operation as said regeneration implementation conditions is implemented during the said inertial driving | running | working, The said regeneration energy is estimated based on the amount of brake operation as described in any one of Claim 1 thru | or 3 Vehicle control device.
In the case where the brake operation is performed during the inertia traveling, a setting unit for setting a duration of the regenerative traveling is provided,
The vehicle control device according to claim 4, wherein the estimation unit estimates the regenerative energy based on the brake operation amount and the duration.
A storage unit for storing the duration when the regenerative running is performed;
The vehicle control device according to claim 5, wherein the setting unit sets the duration based on a history of the duration stored in the storage unit.
The storage unit stores the duration time for each of the plurality of vehicle driving conditions determined.
The setting unit acquires the history according to a traveling condition of the vehicle and sets the duration based on the history when the brake operation is performed during the inertia traveling. The vehicle control device described.
The regenerative device is a rotating electrical machine (13) that performs regenerative power generation that recovers kinetic energy of the vehicle as electrical energy,
8. The vehicle control device according to claim 1, further comprising: a correction unit that corrects the regenerative energy estimated by the estimation unit based on a state of a storage battery that stores electric power generated by the rotating electrical machine. .
The regenerative device is a rotating electrical machine (13) that performs regenerative power generation that recovers kinetic energy of the vehicle as electrical energy,
The vehicle control device according to claim 1, further comprising a correction unit that corrects the regenerative energy estimated by the estimation unit based on a state of the rotating electrical machine.
In the vehicle, it is possible to apply a rotational force to the output shaft by a rotating machine (13),
When the engine control speed is less than a predetermined value when the travel control unit shifts from the inertia travel to the regenerative travel, the travel control unit operates the rotating machine to increase the engine speed, and the engine speed is predetermined. If it is above, the vehicle control device according to any one of claims 1 to 9 which raises the engine speed by combustion of the engine.
The regenerative device is a rotating machine (13), and is applied to a vehicle in which a gear ratio between the output shaft and the rotating shaft (14) of the rotating machine is variable.
The vehicle control device according to any one of claims 1 to 10, further comprising a shift control unit that changes the speed ratio to a side that suppresses a decrease in the engine rotation speed in the inertia traveling.
The speed ratio is a ratio of the rotational speed of the rotary shaft of the rotating machine to the rotational speed of the output shaft,
The shift control unit according to claim 11, wherein when the predetermined inertial travel execution condition is satisfied, the shift ratio is increased more than before, and when the inertial travel is canceled, the shift ratio is decreased. Vehicle control device.
The speed ratio is a ratio of the rotational speed of the rotary shaft of the rotating machine to the rotational speed of the output shaft,
The shift control unit increases the gear ratio more than before when the predetermined inertial running execution condition is satisfied, and when the engine rotation speed becomes equal to or higher than a predetermined rotation speed due to the adjustment of the engine rotation speed. The vehicle control device according to claim 11, wherein the gear ratio is reduced.
The regenerative device is a rotating electrical machine (13) that performs regenerative power generation that recovers kinetic energy of the vehicle as electrical energy, and is applied to a vehicle in which the regenerative power generation by the rotating electrical machine is performed at a predetermined output or less,
When the brake operation is performed during the inertial traveling, a setting unit that sets a duration of the regenerative traveling and a request output that requests the regenerative traveling;
A permission unit that permits the regenerative power generation at an output larger than the predetermined output when the duration is equal to or shorter than a predetermined time and the required output is equal to or greater than a predetermined value;
The vehicle control device according to any one of claims 1 to 4 and claim 8 to 13.