JP7003516B2 - Vehicle control device - Google Patents

Description

The present invention relates to a vehicle control device.

Conventionally, as a technique for efficiently recovering deceleration energy by increasing the amount of power generation of a generator such as an alternator during deceleration operation, the one described in Patent Document 1 is known. The one described in Patent Document 1 increases the amount of power generation when the fuel is cut and the automatic transmission is locked up during deceleration operation, and the throttle valve is opened for the excess or deficiency for the required deceleration. Compensation is made by controlling the degree and controlling the brake operation. Further, in Patent Document 1, the pumping loss is reduced by increasing the throttle valve opening degree by the amount of increasing the amount of power generation. As a result, the one described in Patent Document 1 can efficiently recover the deceleration energy at the time of fuel cut, and can control the deceleration to meet the driver's request.

Japanese Unexamined Patent Publication No. 11-107805

However, in the case described in Patent Document 1, as a result of determining the amount of power generation according to the required deceleration, fuel injection may be restarted in a state where the throttle valve opening degree is large and the intake air amount is large. Therefore, when the intake air amount is large when the fuel injection is restarted, it is necessary to increase the fuel injection amount, which causes an increase in fuel consumption.

The present invention has been made by paying attention to the above-mentioned problems, and provides a vehicle control device capable of suppressing fuel consumption at the time of recovery from a fuel cut and improving fuel efficiency. It is the purpose.

The present invention is a vehicle control device mounted on a vehicle having an engine, a generator connected to the engine, and a battery charged by the generator, and the vehicle speed is accompanied by a fuel cut of the engine. The vehicle is provided with a control unit that controls the generator so as to generate a reference regenerative torque, which is the regenerative torque of the generator in response to the driver's deceleration request during deceleration fuel cut. The control unit includes a stepless transmission having an input shaft to which the rotation of the vehicle is input, and when the control unit determines that there is a deceleration request when the vehicle speed is within a predetermined low vehicle speed region, the control unit receives the reference regeneration torque. When it is determined that there is no deceleration request, a decrease correction is performed with respect to the reference regeneration torque, and the amount of change in the regeneration torque caused by the increase correction or the decrease correction is based on the change in pumping loss. It has a shift map that controls the intake air amount of the engine so as to cancel each other out, and defines the relationship between the speed of the vehicle, the number of revolutions of the input shaft, and the amount of depression of the accelerator pedal by the gear ratio of the stepless transmission. In the shift map, a region below a predetermined vehicle speed at which the shift line applied when the accelerator pedal is not depressed and the minimum shift ratio line at which the shift ratio is minimized intersect is set as the low vehicle speed region. It is characterized by that.

As described above, according to the above-mentioned invention, the fuel consumption at the time of returning from the fuel cut can be suppressed, and the fuel consumption can be improved.

FIG. 1 is a configuration diagram of a vehicle including a vehicle control device according to an embodiment of the present invention. FIG. 2 is a flowchart illustrating a regenerative power generation operation by a vehicle control device according to an embodiment of the present invention. FIG. 3 is a lockup clutch control table used for engagement control of the lockup clutch by the vehicle control device according to the embodiment of the present invention. FIG. 4 is a regenerative torque correction map used during regenerative power generation of ISG by the vehicle control device according to the embodiment of the present invention. FIG. 5 is a shift map used for shift control of a transmission by a vehicle control device according to an embodiment of the present invention. FIG. 6 is a timing chart illustrating the transition of the vehicle state at the time of executing the regenerative power generation operation by the vehicle control device according to the embodiment of the present invention.

The vehicle control device according to an embodiment of the present invention is a vehicle control device mounted on a vehicle having an engine, a generator connected to the engine, and a battery charged by the generator. A control unit that controls the generator to generate a reference regenerative torque, which is the regenerative torque of the generator in response to the driver's deceleration request, is provided during deceleration when the vehicle speed decreases with the engine fuel cut. When the vehicle speed is within the predetermined low vehicle speed region, the control unit makes an increase correction for the reference regenerative torque when it determines that there is a deceleration request, and when it determines that there is no deceleration request, it applies to the reference regenerative torque. It is characterized in that a decrease correction is performed and the intake air amount of the engine is controlled so that the change amount of the regenerative torque caused by the increase correction or the decrease correction is offset by the change amount of the pumping loss. Thereby, the vehicle control device according to the embodiment of the present invention can suppress the fuel consumption at the time of returning from the fuel cut, and can improve the fuel efficiency.

Hereinafter, a vehicle control device according to an embodiment of the present invention will be described with reference to the drawings. 1 to 6 are diagrams illustrating a vehicle control device according to an embodiment of the present invention.

As shown in FIG. 1, the vehicle 10 includes an engine 20, an ISG (Integrated Starter Generator) 40, a continuously variable transmission 30, a drive wheel 12, and an ECU (ECU) as a control unit that comprehensively controls the vehicle 10. Electronic Control Unit) 50 and.

A plurality of cylinders are formed in the engine 20. In this embodiment, the engine 20 is configured to perform a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke for each cylinder. The engine 20 is provided with an intake port 20C communicating with the combustion chamber 20B of each cylinder and an intake pipe 22 for introducing air into the intake port 20C. The intake pipe 22 forms a diverse portion (manifold) that branches toward each intake port 20C at the end on the intake port 20C side, and air is introduced into each intake port 20C.

The intake pipe 22 is provided with a throttle valve 23, and the throttle valve 23 adjusts the amount of air passing through the intake pipe 22 (intake intake amount). The throttle valve 23 includes an electronically controlled throttle valve that is opened and closed by a motor (not shown).

The throttle valve 23 is electrically connected to the ECU 50, and the opening degree of the throttle valve 23 (hereinafter, also referred to as a throttle opening degree) is controlled by the ECU 50.

The engine 20 is provided with an injector 24 for injecting fuel into the combustion chamber 20B via the intake port 20C and a spark plug 25 for igniting the air-fuel mixture in the combustion chamber 20B for each cylinder. The injector 24 and the spark plug 25 are electrically connected to the ECU 50.

The fuel injection amount and fuel injection timing of the injector 24, the ignition timing and the discharge amount of the spark plug 25 are controlled by the ECU 50.

The engine 20 is provided with a crank angle sensor 27, which detects the engine rotation speed based on the rotation position of the crank shaft 20A and transmits a detection signal to the ECU 50.

The continuously variable transmission 30 is provided between the engine 20 and the drive wheels 12, and shifts the rotation transmitted from the engine 20 to drive the drive wheels 12 via the drive shaft 11. There is. The continuously variable transmission 30 includes an input shaft 30A, a torque converter 30B, a lockup clutch 30C, a speed change mechanism 30E, and a differential mechanism 30F.

The torque converter 30B amplifies the torque by converting the rotation transmitted from the engine 20 into torque via the working fluid. When the lockup clutch 30C is released, power is mutually transmitted between the engine 20 and the transmission mechanism 30E via the working fluid.

When the lockup clutch 30C is engaged (engaged), power is directly transmitted between the engine 20 and the speed change mechanism 30E via the lockup clutch 30C.

The power whose torque is amplified in the torque converter 30B is transmitted to the input shaft 30A of the transmission mechanism 30E.

The speed change mechanism 30E is composed of a CVT (Continuously Variable Transmission), and automatically shifts gears steplessly by a set of pulleys wound with a metal belt. The change of the gear ratio in the continuously variable transmission 30 and the engagement or disengagement of the lockup clutch 30C are controlled by the ECU 50.

The differential mechanism 30F is connected to the left and right drive shafts 11, and the power shifted by the speed change mechanism 30E is transmitted to the left and right drive shafts 11 so as to be differentially rotatable.

The vehicle 10 includes an accelerator opening sensor 13A, and the accelerator opening sensor 13A detects an operation amount of the accelerator pedal 13 (hereinafter, simply referred to as an accelerator opening) and transmits a detection signal to the ECU 50.

The vehicle 10 includes a brake stroke sensor 14A, which detects the operation amount of the brake pedal 14 (hereinafter, simply referred to as “brake stroke”) and transmits a detection signal to the ECU 50.

The vehicle 10 includes a vehicle speed sensor 12A, which detects the vehicle speed based on the rotational speed of the drive wheels 12 and transmits a detection signal to the ECU 50. The detection signal of the vehicle speed sensor 12A is used in the ECU 50 or another controller to calculate the slip ratio of each drive wheel 12 with respect to the vehicle speed.

The vehicle 10 includes an atmospheric pressure sensor 81, a MAF sensor 82, a P sensor 83, and an intake air temperature sensor 84. The atmospheric pressure sensor 81 is provided on the upstream side of the throttle valve 23 inside the intake pipe 22, measures the atmospheric pressure, and transmits the measured atmospheric pressure to the ECU 50.

The MAF sensor 82 is provided on the upstream side of the throttle valve 23 inside the intake pipe 22, measures the intake amount (the amount of intake air), and transmits the measured intake amount to the ECU 50.

Further, the P sensor 83 is provided on the downstream side of the throttle valve 23 inside the intake pipe 22, measures the intake pressure (MAP: Manifold Absolute Pressure), and transmits the measured intake pressure to the ECU 50.

The intake air temperature sensor 84 is provided on the downstream side of the throttle valve 23 inside the intake pipe 22, measures the intake air temperature (intake air temperature), and transmits the measured intake air temperature to the ECU 50.

The vehicle 10 includes a starter 26, which includes a motor (not shown) and a pinion gear fixed to the rotating shaft of the motor. On the other hand, a disk-shaped drive plate (not shown) is fixed to one end of the crank shaft 20A of the engine 20, and a ring gear is provided on the outer peripheral portion of the drive plate.

The starter 26 drives the motor according to the command of the ECU 50, engages the pinion gear with the ring gear, and rotates the ring gear to start the engine 20. In this way, the starter 26 starts the engine 20 via a gear mechanism including a pinion gear and a ring gear.

The ISG 40 is a rotary electric machine that integrates a starting device for starting the engine 20 and a generator for generating electric power. The ISG 40 has a function of a generator that generates electric power by external power and a function of an electric motor that generates power by being supplied with electric power.

The ISG 40 is always connected to the engine 20 via a winding transmission mechanism including a pulley 41, a crank pulley 21 and a belt 42, and mutually transmits power to and from the engine 20. More specifically, the ISG 40 includes a rotating shaft 40A, and a pulley 41 is fixed to the rotating shaft 40A.

A crank pulley 21 is fixed to the other end of the crank shaft 20A of the engine 20. A belt 42 is hung on the crank pulley 21 and the pulley 41. A sprocket and a chain can also be used as the winding transmission mechanism.

The ISG 40 is driven as an electric motor to rotate the crank shaft 20A and start the engine 20. Here, the vehicle 10 of this embodiment includes an ISG 40 and a starter 26 as a starting device for the engine 20.

The starter 26 is mainly used for cold start of the engine 20 based on the start operation of the driver, and the ISG 40 is mainly used for restarting the engine 20 from the idling stop.

The ISG 40 can also start the cold engine 20, but the vehicle 10 is equipped with a starter 26 for a reliable cold start of the engine 20.

For example, in winter in a cold region or the like, it may be difficult to start the engine 20 with the power of the ISG 40 due to an increase in the viscosity of the lubricating oil, or the ISG 40 may fail. In consideration of such a case, the vehicle 10 is provided with both the ISG 40 and the starter 26 as a starting device.

The power generated by the ISG 40 is transmitted to the drive wheels 12 via the crank shaft 20A of the engine 20, the continuously variable transmission 30, and the drive shaft 11.

Therefore, the vehicle 10 can realize not only traveling by the power of the engine 20 (engine torque) (hereinafter, also referred to as engine traveling) but also traveling by assisting the engine 20 by the power of the ISG 40 (motor torque).

As described above, the vehicle 10 constitutes a parallel hybrid system capable of traveling by using at least one of the power of the engine 20 and the power of the ISG 40.

Further, a part of the driving force of the engine 20 is transmitted to the ISG 40 and used for power generation in the ISG 40. At this time, a load torque corresponding to the amount of power generation acts on the engine 20 from the ISG 40. Further, the rotation of the drive wheels 12 is transmitted to the ISG 40 via the drive shaft 11, the continuously variable transmission 30, and the crank shaft 20A of the engine 20, and is used for regeneration (power generation) in the ISG 40.

The vehicle 10 includes a battery 70, which comprises a rechargeable secondary battery. The number of cells and the like of the battery 70 is set so as to generate an output voltage of about 12 V.

The battery 70 is provided with a battery state detection unit 70A, which detects the voltage between terminals of the battery 70, the ambient temperature, and the input / output current, and outputs a detection signal to the ECU 50. The ECU 50 detects the state of charge (SOC) based on the voltage between the terminals of the battery 70, the ambient temperature, and the input / output current. The state of charge of the battery 70 is managed by the ECU 50.

Power cables 61 and 64 are connected to the battery 70. The power cable 61 connects the battery 70 and the starter 26, and supplies the power of the battery 70 to the starter 26.

The power cable 64 connects the battery 70 and the ISG 40 so that the power of the battery 70 is supplied to the ISG 40 when the ISG 40 is powered, and the power generated by the ISG 40 is supplied to the battery 70 when the ISG 40 is regenerated. It has become.

The battery 70 also supplies electric power to other electric loads (not shown). The electric load includes a stability control device that prevents the vehicle from skidding, an electric power steering control device that electrically assists the operating force of the steering wheel, a headlight, a blower fan, and the like.

Electrical loads also include wipers, electric cooling fans that blow cooling air to radiators (not shown), instrument panel lamps and meters (not shown), and car navigation systems.

The ECU 50 is a computer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data, an input port, and an output port. It is composed of units.

The ROM of the computer unit stores various constants, various maps, and the like, as well as a program for making the computer unit function as an ECU 50. That is, when the CPU executes the program stored in the ROM with the RAM as the work area, these computer units function as the ECU 50 in this embodiment.

Various sensors including the crank angle sensor 27, the accelerator opening sensor 13A, the brake stroke sensor 14A, the vehicle speed sensor 12A, and the battery status detection unit 70A are connected to the input port of the ECU 50.

Further, various sensors such as the above-mentioned atmospheric pressure sensor 81, MAF sensor 82, P sensor 83, and intake air temperature sensor 84 are connected to the input port of the ECU 50.

Various control objects including the throttle valve 23, the injector 24, the spark plug 25, the ISG 40, the continuously variable transmission 30, and the starter 26 of the engine 20 are connected to the output port of the ECU 50. The ECU 50 controls various control targets including the engine 20 and the continuously variable transmission 30 based on the information obtained from the various sensors.

In this embodiment, the ECU 50 controls the ISG 40 so as to generate a regenerative torque according to the driver's deceleration request during the deceleration fuel cut in which the vehicle speed decreases due to the fuel cut of the engine 20. Here, the regenerative torque corresponding to the deceleration request of the driver is the regenerative torque of the ISG 40 associated with the braking force requested by the driver to the vehicle 10 by the brake operation.

That is, the ECU 50 generates the regenerative torque according to the brake stroke and the like by the ISG 40, so that at least a part of the braking force required by the driver by the brake operation is generated by the regenerative torque.

As long as the braking force required by the driver can be satisfied, the braking force of the friction brake may be weakened by the amount of the braking force generated by the regenerative torque by an ABS device (not shown). By doing so, the energy lost as heat by the friction brake can be reduced, and the energy corresponding to that amount can be recovered as electric energy.

Further, in the present embodiment, when the vehicle speed is within a predetermined low vehicle speed region, the ECU 50 performs an increase correction on the reference regenerative torque when it is determined that there is a deceleration request, and when it is determined that there is no deceleration request. Decrease correction is performed for the reference regenerative torque. Further, the ECU 50 controls the intake air amount of the engine 20 so that the change amount of the regenerative torque caused by the increase correction or the decrease correction is offset by the change amount of the pumping loss.

Further, the ECU 50 determines that there is no deceleration request when the depression amount of the brake pedal 14 is less than the predetermined depression amount or the brake hydraulic pressure is less than the predetermined hydraulic pressure.

Further, the ECU 50 has a shift map that defines the relationship between the vehicle speed, the rotation speed of the input shaft, and the stepping amount of the accelerator pedal 13 with respect to the gear ratio of the continuously variable transmission 30. Then, the ECU 50 sets the region of the predetermined vehicle speed or less at the intersection of the shift line applied when the accelerator pedal 13 is not depressed and the minimum gear ratio line at which the gear ratio is minimized in the shift map as a low vehicle speed region. Set.

Further, the ECU 50 has a first vehicle speed as a predetermined vehicle speed and a second vehicle speed which is smaller than the first vehicle speed and is a threshold value for switching the lockup clutch from engagement to release, and is the first in the shift map. The region below the vehicle speed and above the second vehicle speed is set as the low vehicle speed region.

Further, the ECU 50 may further reduce the intake air amount by a correction amount according to the amount of fuel adhering to the intake port 20C of the engine 20 when the vehicle speed decreases with the fuel cut. That is, a part of the fuel adhering to the inner wall of the intake port 20C due to the fuel injection before the fuel cut stays in the intake port 20C even during the fuel cut.

Therefore, when resuming fuel injection, the fuel injection amount should be increased or decreased according to the amount of stagnant fuel, and if the fuel injection amount is adjusted to the decreasing side, it is adjusted according to the adjustment amount. It is preferable to further reduce the intake air amount by the correction amount.

The regenerative power generation operation by the ECU 50 of the vehicle 10 configured as described above will be described with reference to the flowchart shown in FIG.

In FIG. 2, the ECU 50 repeats the determination of whether or not the regeneration condition is satisfied (step S1). Here, the ECU 50 determines that the regeneration condition is satisfied, for example, when the fuel is cut. It should be noted that the condition that the vehicle speed is decreasing may be further added.

When the regeneration condition is satisfied in step S1, the ECU 50 calculates the charging torque of the ISG 40 (step S2). The charging torque is a torque when the ISG 40 generates electricity, and is a torque that acts as a load on the engine 20 and decelerates the vehicle 10.

In this step S2, the ECU 50 calculates the charging torque with reference to a predetermined regenerative torque map (not shown) based on the vehicle speed, the brake stroke, and the charging state of the battery 70. The charging torque calculated in step S2 corresponds to the reference regenerative torque in the present invention.

Here, in this embodiment, referring to the lockup clutch control table shown in FIG. 3, the ECU 50 releases the lockup clutch 30C when the vehicle speed is decelerated to a vehicle speed corresponding to the accelerator opening degree. In the lockup clutch control table of FIG. 3, the vehicle speed at which the lockedup clutch 30C in the engaged state should be released during fuel cut during deceleration is determined for each accelerator opening, and the ECU 50 is obtained in advance by experiments or the like. It is stored in the ROM of.

According to the lockup clutch control table, for example, when the accelerator opening degree is 0%, the lockup clutch 30C is released by the control of the ECU 50 when the vehicle speed is decelerated to A [km / h]. The vehicle speed A [km / h] corresponds to the second vehicle speed described later.

Further, the ECU 50 not only releases the lockup clutch 30C at the vehicle speed A, but also ends the fuel cut and restarts the combustion injection. As a result, when the lockup clutch 30C is released, the engine 20 resumes autonomous rotation by fuel injection, so that engine stall is prevented.

Next, the ECU 50 detects the brake stroke and the vehicle speed (step S3), and calculates the regenerative torque correction coefficient (step S4). In step S4, the ECU 50 calculates the regenerative torque correction coefficient with reference to the regenerative torque correction map shown in FIG. 4 based on the brake stroke and the vehicle speed detected in step S3.

The regenerative torque correction coefficient is a correction coefficient that is multiplied by the charging torque calculated in step S2. The regenerative torque correction map is stored in the ROM of the ECU 50 after being obtained in advance by an experiment or the like.

In the regenerative torque correction map, a shaded area where the vehicle speed is a low vehicle speed region equal to or lower than the first vehicle speed and higher than the second vehicle speed, and the brake stroke is an open region (referred to as an open region of the brake pedal in the figure). In (hereinafter, also referred to as a reduction correction region), the correction coefficient is set to 0.5. Therefore, in the reduction correction region, the charging torque, which is the reference regeneration torque, is corrected to the reduction side by the ECU 50 (hereinafter, also referred to as reduction correction).

The open area of the brake stroke is a region in which the brake pedal 14 is depressed with a slight brake stroke less than a predetermined depression amount to the extent that braking force is not generated. The brake stroke of this regenerative torque correction map can be replaced with the brake hydraulic pressure, and in that case, the region where the brake hydraulic pressure is less than the predetermined hydraulic pressure is set as the open region.

Further, in the regenerative torque correction map, the region other than the reduction correction region is divided into a plurality of regions according to the combination of the brake stroke and the vehicle speed, and the correction coefficient is set to 1 or more in each of the divided regions. ing.

Therefore, in the region other than the reduction correction region, the charging torque, which is the reference regeneration torque, is corrected to the increase side by the ECU 50 (hereinafter, also referred to as increase correction). In this embodiment, 1.0, 1.2, 1.5, and 2.0 are set as correction coefficients in each area other than the reduction correction area in the regenerative torque correction map.

Following step S4, the ECU 50 determines the regenerative torque corrected by the complementary coefficient (step S5). Here, the ECU 50 calculates the regenerative torque by multiplying the charge torque by the correction coefficient.

Next, the ECU 50 controls the ISG 40 so as to generate the corrected regenerative torque in step S6. Further, in step S6, the ECU 50 controls the throttle opening of the throttle valve 23 and controls the intake air amount of the engine 20 so that the change amount of the regenerative torque caused by the correction is offset by the change amount of the pumping loss.

Here, the regenerative torque and the pumping loss act as a so-called engine brake for decelerating the vehicle. Further, the pumping loss becomes smaller as the throttle opening becomes larger, and becomes larger as the throttle opening becomes smaller.

Therefore, for example, when the regenerative torque is reduced and corrected, the ECU 50 reduces the throttle opening and increases the pumping loss so as to offset (complement) the action of the engine brake that is reduced by the correction. do.

In this embodiment, when the vehicle speed is within the predetermined low vehicle speed region and the brake pedal 14 is not depressed, the vehicle speed falls within the reduction correction region of FIG. 4, so that the ECU 50 determines the charging torque (reference regeneration torque). ) Is reduced by using a correction coefficient of 0.5. In this case, the ECU 50 reduces the throttle opening degree so as to offset the action of the engine brake by the amount reduced by the reduction correction.

On the other hand, when the vehicle speed is outside the predetermined low vehicle speed region, or when the brake pedal 14 is depressed, it corresponds to the region outside the reduction correction region in FIG. 4, so that the ECU 50 determines the vehicle speed and the brake stroke according to the vehicle speed and the brake stroke. , The charge torque (reference regeneration torque) is increased and corrected by using the correction coefficients 1.0, 1.2, 1.5 or 2.00. In this case, the ECU 50 increases the throttle opening degree so as to offset the action of the engine brake increased by the increase correction.

Since the purpose of the process in step S6 is to finally control the pumping loss, instead of controlling the throttle opening to adjust the intake air amount, the valve timings of the intake valve and the exhaust valve (not shown) are set. It may be controlled to adjust the intake air amount.

After step S6, the ECU 50 determines whether or not the predetermined regeneration end condition is satisfied (step S7), returns to step S2 and repeats the processing up to step S6 until the regeneration end condition is satisfied, and repeats the process up to step S6. When is satisfied, this operation ends.

The CVT shift map shown in FIG. 5 is a map used by the ECU 50 when controlling the gear ratio of the continuously variable transmission 30, and is a vehicle speed and a rotation speed of the input shaft 30A of the transmission 30 (hereinafter, also referred to as an input shaft rotation speed). ) And the gear ratio corresponding to the accelerator opening.

The shift line corresponding to 0% of the accelerator opening is the shift line used for regenerative power generation during fuel cut during deceleration (indicated as deceleration in the figure) and the shift line used for acceleration by creep torque. There is a line (in the figure, it is added as "acceleration"). In this embodiment, the shift line described as 0% (during deceleration) is used, but the shift line described as 0% (during acceleration) may be used.

Further, in the CVT shift map, the minimum gear ratio line that minimizes the gear ratio (denoted as the highest Hi line in the figure) and the maximum gear ratio line that maximizes the gear ratio (denoted as the lowest line in the figure). And are set. It should be noted that the names of the highest Hi line and the highest Low line described in the figure are names when distinguishing from the viewpoint of whether the gear ratio is for high-speed running or low-speed running.

Further, the above-mentioned first vehicle speed and the second vehicle speed are set in the CVT shift map. In the CVT shift map, the predetermined vehicle speed at the point where the shift line with the accelerator opening of 0% (during deceleration) and the minimum shift ratio line intersect (referred to as point P (1) in the figure) is the above-mentioned first. Vehicle speed. Then, the region below the first vehicle speed and above the second vehicle speed is set as the above-mentioned low vehicle speed region.

In the CVT shift map, when the accelerator opening is 0% and the vehicle speed decreases, the gear ratio moves from point P (0) to point P (1) along the minimum gear ratio line, and then the accelerator opening is 0. It moves to the point P (2) along the shift line of% (during deceleration). The point P (2) is a point where the vehicle speed becomes the second vehicle speed. This second vehicle speed is a threshold value for switching the lockup clutch 30C from engagement to release when the accelerator opening degree is 0% (during deceleration) as described above.

In FIG. 6, the vertical axis indicates the fuel cut state, the regenerative power generation state, the brake stroke, the regenerative torque before correction (referred to simply as the regenerative torque in the figure), and the regenerative torque after correction (Qel after regenerative correction in the figure). (Note), deceleration torque, intake air amount are shown, and the horizontal axis shows time. The regenerative torque before correction is the charging torque as the reference regenerative torque.

Here, the deceleration torque in the figure represents a plurality of braking torques for decelerating the vehicle 10, the regenerative torque after the reduction correction shown by the broken line, the pumping loss shown by the thin solid line, and the brake shown by the thick solid line. It consists of braking torque (denoted as hydraulic brake in the figure). The brake braking torque represents the braking force of the friction brake operated via the brake pedal 14 in terms of torque.

In addition, in FIG. 6, the vehicle state and the like according to this embodiment are shown by a solid line, and the value for comparison or the comparison example is shown by a broken line. Specifically, in the column of the regenerative torque after the correction, the value of the regenerative torque after the correction is shown by a solid line, and the value of the regenerative torque before the correction is also shown by a broken line as a value for comparison.

Further, in the column of the intake air amount, the intake air amount according to the present embodiment is shown by a solid line, and the intake air amount according to the comparative example is also shown by a broken line. The intake air amount according to the comparative example is the intake air amount when the regenerative torque is not corrected and the pumping loss is not adjusted by controlling the throttle opening degree. Further, in the column of deceleration torque, the value of the regenerative torque when the correction is not performed, that is, the value of the regenerative torque before the correction is also shown by a broken line as a comparative example.

At time t0 in the initial state, the accelerator opening is constant, fuel cut and regenerative power generation are not performed, and the vehicle 10 is accelerating or traveling at a constant speed. After that, at time t1, the accelerator opening is reduced to fully closed, so that fuel cut and regenerative power generation are carried out.

In this embodiment, when the brake is not operated, the regenerative torque (reference regenerative torque, charging torque) is corrected for reduction, and the regenerative torque after the reduction correction is generated by the ISG 40. Further, the throttle opening is controlled to the valve closing side in order to cancel the regenerative torque corresponding to the reduced correction, and the pumping loss is increased.

Therefore, the deceleration torque at time t1 is composed of the regenerative torque (shown by the alternate long and short dash line) after the reduction correction and the pumping loss (shown by the solid line) increased by the reduction correction of the regenerative torque.

Therefore, it is possible to make the state where the pumping loss is large and the throttle opening is small as compared with the regenerative torque (indicated by the broken line) in the comparative example when the reduction correction is not performed. Therefore, the amount of intake air at time t1 is smaller than that of the comparative example shown by the broken line.

After that, the brake stroke increases at time t2 and becomes constant at time t3. When the brake pedal 14 is depressed as at time t3, the deceleration torque is composed of the regenerative torque after the increase correction, the pumping loss reduced by the increase correction of the regenerative torque, and the braking torque of the friction brake. Will be done. Therefore, the efficiency of the engine 20 can be improved by the reduction of the pumping loss.

After that, at time t4, the driver releases the depression of the brake pedal 14 in order to switch to the accelerator pedal 13, and the brake stroke is set to 0. As a result, as at time t1, the pumping loss is large and the throttle opening is small.

After that, when the driver depresses the accelerator pedal 13 at time t5, the fuel cut is completed and the fuel injection is restarted in a state where the throttle opening is small and the intake air amount is smaller than that in the comparative example. Therefore, the engine 20 restarts the self-sustaining operation with a small fuel injection amount corresponding to the small intake air amount. Therefore, it is possible to suppress the fuel consumption at the time of returning from the fuel cut.

As described above, in the present embodiment, when the vehicle speed is within the predetermined low vehicle speed region, when it is determined that there is a deceleration request, the ECU 50 performs an increase correction on the reference regenerative torque and determines that there is no deceleration request. If so, the reduction correction is performed for the reference regenerative torque. Further, the ECU 50 controls the intake air amount of the engine 20 so that the change amount of the regenerative torque caused by the increase correction or the decrease correction is offset by the change amount of the pumping loss.

Here, when the vehicle speed is in the low vehicle speed region, it is assumed that the accelerator pedal 13 is depressed again and fuel injection is restarted. Therefore, in this embodiment, when it is determined that the vehicle speed is within the predetermined low vehicle speed region and there is a deceleration request, an increase correction is performed for the reference regenerative torque in advance prior to restarting the fuel injection. The amount of intake air can be reduced. As a result, the fuel injection amount at the time of restarting the fuel injection can be reduced.

Therefore, it is possible to suppress the fuel consumption at the time of returning from the fuel cut, and it is possible to improve the fuel efficiency. In addition to this, in this embodiment, by suppressing the fuel consumption at the time of returning from the fuel cut, it is possible to suppress the sudden increase in the engine torque immediately after the restart of fuel injection, so that a shock occurs due to the sudden increase in the engine torque. Can be prevented.

Further, in the present embodiment, the ECU 50 determines that there is no deceleration request when the depression amount of the brake pedal 14 is less than the predetermined depression amount or the brake hydraulic pressure is less than the predetermined hydraulic pressure.

As a result, the presence or absence of a deceleration request can be reliably and clearly determined, and the intake air amount can be reliably reduced when the fuel injection is restarted.

Further, in the present embodiment, the vehicle 10 includes a continuously variable transmission 30 having an input shaft 30A to which the rotation of the engine 20 is input. The ECU 50 has a shift map that defines the relationship between the vehicle speed, the number of rotations of the input shaft, and the stepping amount of the accelerator pedal 13 and the gear ratio of the stepless transmission 30, and the accelerator pedal 13 in the shift map is depressed. A region below a predetermined vehicle speed at which the shift line applied when the gear ratio is not present intersects with the minimum gear ratio line that minimizes the gear ratio is set as the low vehicle speed region.

As a result, the predetermined vehicle speed and the low vehicle speed region are set in relation to the minimum gear ratio line and the like in the shift map. Therefore, in such a low vehicle speed region, the regenerative torque is compared with the case where the vehicle speed region exceeds the predetermined vehicle speed. The amount of influence on the deceleration of the vehicle 10 and the like due to the increase correction is reduced. Therefore, even if the regenerative torque is increased and corrected, the braking effect does not occur more than requested by the driver, and it is possible to prevent the driver from feeling uncomfortable.

Further, in the present embodiment, the continuously variable transmission 30 has a torque converter 30B with a lockup clutch 30C between the continuously variable transmission 30 and the engine 20. The ECU 50 has a first vehicle speed as a predetermined vehicle speed and a second vehicle speed that is smaller than the first vehicle speed and is a threshold value for switching the lockup clutch from engagement to release, and is the first in the shift map. The region below the vehicle speed and above the second vehicle speed is set as the low vehicle speed region.

As a result, even if the rise of the engine torque becomes large when the engine 20 returns to the combustion operation after finishing the fuel cut, the lockup clutch 30C is released, so that the fluctuation of the engine torque changes in the vehicle 10. It can be prevented from being transmitted to. Further, in this embodiment, the vehicle speed at which the lockup clutch 30C is released is set to the lower limit of the low vehicle speed region, and if the vehicle speed is lower than this, the regenerative torque is not corrected and the throttle opening is not adjusted according to this correction. It is possible to prevent the intake air amount required for returning to the combustion operation from being insufficient, and it is possible to prevent the engine from stall due to the insufficient intake air amount.

Further, in the present embodiment, the ECU 50 further reduces the intake air amount by a correction amount according to the amount of fuel adhering to the intake port 20C of the engine 20 when the vehicle speed decreases due to the fuel cut. You may.

As a result, when the amount of fuel adhering to the intake port 20C is small, the amount of fuel at the time of returning to the combustion operation may increase, but the amount of intake air is further reduced by the correction amount according to the amount of adhering fuel. By setting the fuel injection amount, the fuel injection amount at the time of returning to the combustion operation can be further reduced. The amount of adhered fuel may be calculated based on the adhered fuel model obtained in advance by experiments or the like, or may be estimated based on the duration of the fuel cut state.

Although embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

10 Vehicle 13 Accelerator pedal 14 Brake pedal 20 Engine 20C Intake port 23 Throttle valve 30 Continuously variable transmission 30A Input shaft 30B Torque converter 30C Lock-up clutch 40 ISG (generator)
50 ECU (control unit)

Claims (4)

A vehicle control device mounted on a vehicle having an engine, a generator connected to the engine, and a battery charged by the generator.
A control unit that controls the generator so as to generate a reference regenerative torque, which is the regenerative torque of the generator in response to the driver's deceleration request during the deceleration fuel cut in which the vehicle speed decreases with the fuel cut of the engine. Equipped with
The vehicle comprises a continuously variable transmission having an input shaft into which the rotation of the engine is input.
The control unit
When the vehicle speed is within a predetermined low vehicle speed region, when it is determined that there is a deceleration request, an increase correction is performed on the reference regenerative torque, and when it is determined that there is no deceleration request, the reference regenerative torque is applied. And make a reduction correction
The intake air amount of the engine is controlled so that the change amount of the regenerative torque caused by the increase correction or the decrease correction is offset by the change amount of the pumping loss .
It has a shift map that defines the relationship between the speed of the vehicle, the number of revolutions of the input shaft, and the amount of depression of the accelerator pedal with respect to the gear ratio of the continuously variable transmission.
In the shift map, a region below a predetermined vehicle speed where the shift line applied when the accelerator pedal is not depressed and the minimum gear ratio line at which the gear ratio is minimized intersect is set as the low vehicle speed region. A vehicle control device characterized by that. A vehicle control device mounted on a vehicle having an engine, a generator connected to the engine, and a battery charged by the generator.
A control unit that controls the generator so as to generate a reference regenerative torque, which is the regenerative torque of the generator in response to the driver's deceleration request during the deceleration fuel cut in which the vehicle speed decreases with the fuel cut of the engine. Equipped with
The control unit
When the vehicle speed is within a predetermined low vehicle speed region, when it is determined that there is a deceleration request, an increase correction is performed on the reference regenerative torque, and when it is determined that there is no deceleration request, the reference regenerative torque is applied. And make a reduction correction
The intake air amount of the engine is controlled so that the change amount of the regenerative torque caused by the increase correction or the decrease correction is offset by the change amount of the pumping loss.
A vehicle control characterized by further reducing the intake air amount by a correction amount according to the amount of fuel adhering to the intake port of the engine when the vehicle speed decreases with the fuel cut. Device. The continuously variable transmission has a torque converter with a lockup clutch between the continuously variable transmission and the engine.
The control unit
The first vehicle speed as the predetermined vehicle speed and
It has a second vehicle speed that is smaller than the first vehicle speed and is a threshold value for switching the lockup clutch from engagement to release.
The vehicle control device according to claim 1, wherein a region of the first vehicle speed or lower and higher than the second vehicle speed in the shift map is set in the low vehicle speed region . The control unit
The vehicle according to any one of claims 1 to 3, wherein when the amount of depression of the brake pedal is less than the predetermined amount of depression or the brake hydraulic pressure is less than the predetermined hydraulic pressure, it is determined that there is no deceleration request. Control device.

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