JP2021148143A - Control device of vehicle - Google Patents

Abstract

To provide a control device of a vehicle which can change a gear change ratio of a transmission to a desired gear change ratio while the rotation of an engine is stopped even if drop promotion control of an engine rotational speed is performed.SOLUTION: In a control device of a vehicle which has an engine, a CVT, a hydraulic circuit and an oil pump for performing a gear change operation for changing a gear change ratio γ of the CVT, and an ISG which can transmit power to the engine, and in which the oil pump is driven by the power of the engine, the control device comprises a control part which can perform drop promotion control for promoting the decrease of the rotation of the engine by the ISG in a period in which the rotation of the engine is stopped after a prescribed engine stop condition is established. The control part performs the drop promotion control on condition that a prescribed execution condition is established, and the prescribed execution condition can change the gear change ratio γ of the CVT to a target gear change ratio γtgt by driving the oil pump up until the rotation of the engine is stopped when the drop promotion control is performed.SELECTED DRAWING: Figure 4

Description

The present invention relates to a vehicle control device.

According to Patent Document 1, it is determined that the engine rotation speed is in a predetermined rotation speed range including at least the resonance region of the engine during the rotation reduction period when the engine rotation speed drops to zero after the combustion of the engine is stopped. In this case, the first rotation descent process that increases the descent speed of the engine rotation speed by the regenerative power generation of the revolving electric machine, and the second rotation that increases the descent speed of the engine rotation speed by driving the revolving electric machine to the reverse rotation side. A technique for selectively performing one of the descent treatments is disclosed.

JP-A-2017-202726

By the way, as a transmission that shifts the rotation of an engine, there is a transmission that performs a shifting operation by the flood pressure generated by a hydraulic device such as an oil pump driven by the power of the engine. In such a transmission, if the rotation of the engine is stopped, the hydraulic system cannot be operated, so that the shifting operation cannot be performed.

When the technique described in Patent Document 1 described above is applied to a vehicle equipped with a transmission as described above, when the first rotation descent process or the second rotation descent process is executed, the descent speed of the engine rotation speed becomes large. Along with this, the rate of decrease in the inertial torque of the engine also increases. As a result, the time from the stop of combustion of the engine to the stop of rotation of the engine is shortened, and the oil pressure generated by the hydraulic system is reduced.

Therefore, when the first rotation descent process or the second rotation descent process is executed, the gear ratio of the transmission may not be changed to a desired gear ratio between the stop of combustion of the engine and the stop of rotation of the engine. ..

If the gear ratio of the transmission cannot be changed to the desired gear ratio between the stop of engine combustion and the stop of engine rotation, for example, when the engine that has stopped idling is restarted and accelerated or started while the vehicle is decelerating. A shift operation for changing the gear ratio to a desired gear ratio is required when the engine is restarted. In this case, the responsiveness of acceleration or starting after restarting the engine may deteriorate.

The present invention has been made in view of the above circumstances, and even when the reduction promotion control of the engine rotation speed is executed, the gear ratio of the transmission is desired until the rotation of the engine is stopped. It is an object of the present invention to provide a vehicle control device capable of changing the gear ratio of.

In order to achieve the above object, the present invention relates to an engine, a transmission that shifts and outputs the rotation of the engine, a transmission that performs a shifting operation that changes the gear ratio of the transmission, and the engine. A vehicle control device including a motor capable of transmitting power and the transmission is driven by the power of the engine, from the time when a predetermined engine stop condition is satisfied until the rotation of the engine is stopped. During the period, the motor includes a control unit capable of executing descent promotion control for promoting a decrease in the rotation of the engine, and the control unit executes the descent promotion control on condition that a predetermined execution condition is satisfied. Then, under the predetermined execution condition, when the descent promotion control is executed, the transmission is driven to set the gear ratio of the transmission to the target gear ratio until the rotation of the engine is stopped. It has a configuration that is changeable.

According to the present invention, even when the reduction promotion control of the engine rotation speed is executed, the gear ratio of the transmission can be changed to a desired gear ratio until the engine rotation is stopped. A control device can be provided.

FIG. 1 is a schematic configuration diagram of a vehicle equipped with a vehicle control device according to the first embodiment of the present invention. FIG. 2 is a graph showing an example of a change in engine rotation speed during execution of descent promotion control by an ECU of a vehicle equipped with a vehicle control device according to a first embodiment of the present invention. FIG. 3 is a flowchart showing a flow of post-engine stop processing executed by the ECU of the vehicle equipped with the vehicle control device according to the first embodiment of the present invention. FIG. 4 is an example of a time chart when descent promotion control is executed in a vehicle equipped with the vehicle control device according to the first embodiment of the present invention. FIG. 5 is an example of a time chart when the descent promotion control is executed while the output of the ISG is limited in the vehicle equipped with the vehicle control device according to the first embodiment of the present invention. FIG. 6 is an example of a time chart when descent promotion control is executed in a vehicle equipped with a vehicle control device according to a modification of the first embodiment of the present invention. FIG. 7 is a schematic configuration diagram of a vehicle equipped with a vehicle control device according to a second embodiment of the present invention. FIG. 8 is a flowchart showing a flow of post-engine stop processing executed by the ECU of the vehicle equipped with the vehicle control device according to the second embodiment of the present invention. FIG. 9 is a flowchart showing a flow of a shiftability determination process executed by the ECU of the vehicle equipped with the vehicle control device according to the second embodiment of the present invention.

The shift control device according to an embodiment of the present invention includes an engine, a transmission that shifts and outputs the rotation of the engine, a shift device that performs a shift operation for changing the gear ratio of the transmission, and an engine. A vehicle control device that includes a motor capable of transmitting power and whose transmission is driven by the power of the engine, during the period from when a predetermined engine stop condition is satisfied until the rotation of the engine is stopped. , A control unit capable of executing descent promotion control that promotes a decrease in engine rotation by a motor is provided, and the control unit executes descent promotion control on the condition that a predetermined execution condition is satisfied, and the predetermined execution condition is The feature is that the gear ratio of the transmission can be changed to the target gear ratio by driving the transmission until the rotation of the engine is stopped when the descent promotion control is executed. do.

As a result, the speed change control device according to the embodiment of the present invention desires the speed change ratio of the transmission until the rotation of the engine is stopped even when the reduction promotion control of the engine rotation speed is executed. It can be changed to the gear ratio of.

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

(First Example)
As shown in FIG. 1, the vehicle 1 equipped with the vehicle control device according to the first embodiment includes an internal combustion engine type engine 2, a torque converter 3, and a CVT (Continuously Variable Transmission) 4 as a transmission. , A hydraulic circuit 5, a planetary gear mechanism 6, a differential gear 7, a drive wheel 8a and a drive wheel 8b, and an ECU (Electronic Control Unit) 9.

A plurality of cylinders are formed in the engine 2. In this embodiment, the engine 2 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.

An ISG (Integrated Starter Generator) 20 as a motor is connected to the engine 2. The ISG 20 is connected to the crankshaft of the engine 2 via a power transmission member such as a belt or a chain (not shown). The ISG 20 has a function as an electric motor capable of transmitting power to the engine 2 and a function of a generator that converts a rotational force input from a crankshaft into electric power. When the ISG 20 functions as an electric motor, the ISG 20 rotates by being supplied with electric power to rotationally drive the crankshaft of the engine 2.

The torque converter 3 is provided on the power transmission path between the engine 2 and the CVT 4. The torque converter 3 amplifies the torque generated by the engine 2 and outputs the torque to the CVT 4. A counter drive gear 10 and a counter driven gear 11 are provided between the torque converter 3 and the CVT 4.

The CVT 4 is composed of a belt-type continuously variable transmission, and is a transmission that shifts the rotation of the engine 2 and outputs it to the planetary gear mechanism 6. The CVT 4 has a primary pulley 12, a secondary pulley 13, and a belt 14.

The primary pulley 12 and the secondary pulley 13 are each formed with grooves whose widths are adjusted by flood control. The belt 14 is wound around the grooves of the primary pulley 12 and the secondary pulley 13 and sandwiched between the primary pulley 12 and the secondary pulley 13.

The primary pulley 12 has a movable sheave 12a, a fixed sheave 12b, and an input side hydraulic cylinder 15. The movable sheave 12a is provided so as to rotate integrally with the input shaft connected to the torque converter 3 and move in the axial direction thereof.

The fixed sheave 12b is provided so as to rotate integrally with the input shaft and not move in the axial direction thereof. The input side hydraulic cylinder 15 is adapted to move the movable sheave 12a in the axial direction by the primary sheave pressure corresponding to the gear ratio γ of the CVT 4.

Therefore, the primary pulley 12 has a V-shaped groove width between the movable sheave 12a and the fixed sheave 12b by moving the movable sheave 12a in the axial direction by the input side hydraulic cylinder 15 (hereinafter, simply referred to as “V groove width”). Can be changed. That is, the primary pulley 12 changes the winding diameter of the belt 14 by changing the V-groove width.

The secondary pulley 13 has a movable sheave 13a, a fixed sheave 13b, and an output side hydraulic cylinder 16. The movable sheave 13a is provided so as to rotate integrally with the output shaft of the CVT 4 and move in the axial direction thereof.

The fixed sheave 13b is provided so as to rotate integrally with the output shaft and not move in the axial direction thereof. The output-side hydraulic cylinder 16 is adapted to move the movable sheave 13a in the axial direction by the belt pinching pressure required for sandwiching the belt 14.

Therefore, the secondary pulley 13 can change the V-groove width between the movable sheave 13a and the fixed sheave 13b by moving the movable sheave 13a in the axial direction by the output side hydraulic cylinder 16. That is, the secondary pulley 13 changes the winding diameter of the belt 14 by changing the V-groove width.

In this way, in the CVT 4, the V-groove widths of the primary pulley 12 and the secondary pulley 13 change due to the oil pressure supplied from the hydraulic circuit 5 to the input side hydraulic cylinder 15 and the output side hydraulic cylinder 16, and the belt 14 The winding diameter is changed. Therefore, the CVT 4 can change the gear ratio γ steplessly.

Further, in the CVT 4, the force for holding the belt 14 of the output side hydraulic cylinder 16 is the hydraulic circuit 5 so that the “belt slip” in which the belt 14 is slipping on at least one of the primary pulley 12 and the secondary pulley 13 does not occur. It is designed to be adjusted by.

The vehicle 1 is provided with an oil pan in which oil is stored and an oil pump 50 that draws oil from the oil pan and supplies it to the flood control circuit 5. In this embodiment, the oil pump 50 is composed of a mechanical oil pump that generates flood pressure by being driven by the driving force of the engine 2.

The hydraulic circuit 5 adjusts the oil pressure of the oil supplied to the lockup clutch of the torque converter 3, the planetary gear mechanism 6, the input side hydraulic cylinder 15, the output side hydraulic cylinder 16, and the like under the control of the ECU 9.

Specifically, the hydraulic circuit 5 has solenoid valves each constituting a plurality of pressure regulating valves, and the duty ratio between the open state and the closed state of each solenoid valve is controlled by the ECU 9.

In this embodiment, the hydraulic circuit 5 and the oil pump 50 adjust the oil pressure generated by the oil pump 50 by the hydraulic circuit 5, so that the oil pressure of the oil supplied to the input side hydraulic cylinder 15 and the output side hydraulic cylinder 16 is increased. To adjust. As a result, the winding diameter of the belt 14 with respect to the primary pulley 12 and the secondary pulley 13 is changed, and the gear ratio γ of the CVT 4 is changed. Therefore, the hydraulic circuit 5 and the oil pump 50 perform a shift operation for changing the gear ratio γ of the CVT 4 by the flood control. The hydraulic circuit 5 and the oil pump 50 in this embodiment constitute a transmission and a hydraulic device.

The planetary gear mechanism 6 switches the rotation direction of the driving force output from the CVT 4 between the forward direction and the reverse direction by the hydraulic circuit 5 controlled by the ECU 9. The driving force output from the planetary gear mechanism 6 is transmitted to the drive wheels 8a and the drive wheels 8b via the reduction gear 60 and the differential gear 7, and the drive wheels 8a and the drive wheels 8b are driven. The planetary gear mechanism 6 may further constitute an auxiliary transmission.

The ECU 9 is composed of a computer unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, and an output port.

The ROM of the ECU 9 stores various control constants, various maps, and the like, as well as a program for causing the computer unit to function as the ECU 9. That is, in the ECU 9, the computer unit functions as the ECU 9 when the CPU executes the program stored in the ROM.

The input port of the ECU 9 has an accelerator opening sensor 41 that detects the opening degree of the accelerator pedal (hereinafter, simply referred to as "accelerator opening degree"), a vehicle speed sensor 42 that detects the vehicle speed, and a shift position sensor that detects the shift position. 43, a crank angle sensor 44, and a brake sensor 45 that detects the amount of depression of the brake pedal are connected. The ECU 9 calculates the engine rotation speed RPM, which is the rotation speed of the engine 2, based on the detection information from the crank angle sensor 44.

Further, at the input port of the ECU 9, a primary pulley speed sensor 46 that detects the rotation speed of the primary pulley 12, a secondary pulley speed sensor 47 that detects the rotation speed of the secondary pulley 13, an input side hydraulic cylinder 15 and an output side oil pressure. A hydraulic sensor 48 that detects the hydraulic pressure P, which is the pressure (line pressure) of the oil supplied to the cylinder 16, is connected.

Further, in the output port of the ECU 9, in addition to the solenoid valve of the hydraulic circuit 5, an injector 51 that injects fuel into the engine 2 and a throttle valve that adjusts the opening degree of the throttle valve 52 that adjusts the intake air amount of the engine 2 The actuator 53 is connected.

The ROM of the ECU 9 contains a shift map in which the gear ratio γ is associated with the vehicle speed and the accelerator opening, and the target oil pressure of the oil required to hold the belt 14 with respect to the gear ratio γ of the CVT 4. The target oil pressure map associated with is stored.

The ECU 9 refers to the shift map and the target oil pressure map on the condition that the shift position selected by the shift position sensor 43 indicates forward or reverse, and determines the accelerator opening detected by the accelerator opening sensor 41. The gear ratio γ of the CVT 4 is determined based on the vehicle speed detected by the vehicle speed sensor 42, and the gear ratio γ of the CVT 4 is controlled via the hydraulic circuit 5.

When a predetermined engine stop condition is satisfied, the ECU 9 executes idling stop control for stopping fuel injection from the injector 51 to stop the engine 2.

The predetermined engine stop condition includes, for example, that the vehicle speed is smaller than the predetermined value, that the brake pedal is depressed, that the SOC (State of charge) of the battery (not shown) is greater than the predetermined value, and the like. Even during deceleration of the vehicle 1, the ECU 9 can stop the engine 2 when the above-mentioned engine stop condition is satisfied.

The ECU 9 drives the ISG 20 to restart the engine 2 when a predetermined engine restart condition is satisfied while the engine 2 is stopped by the idling stop control. The predetermined restart conditions include, for example, that the accelerator pedal has been depressed, that the brake pedal has been released, and the like.

The ECU 9 promotes a decrease in the rotation of the engine 2 by the ISG 20 during a period from the establishment of a predetermined engine stop condition to the stop of the rotation of the engine 2 (hereinafter, this period is referred to as a “rotation descent period”). It has a function as a control unit 100 capable of executing descent promotion control.

The descent promotion control is executed on the condition that a predetermined execution condition is satisfied during the rotation descent period. In the present embodiment, the descent promotion control is a control that promotes a decrease in the engine rotation speed so that the rotation of the engine 2 that decreases during the rotation descent period passes through the resonance region of the engine 2 in a short time.

As shown in FIG. 2, when the engine rotation speed decreases after the fuel injection is stopped, the engine rotation speed passes through the resonance region of the engine 2 shown by the diagonal lines in FIG. The resonance region of the engine 2 is a rotation speed region with 1st_RPM as the upper limit and 2nd_RPM as the lower limit. In the resonance region of the engine 2, the vibration of the engine 2 increases. The descent promotion control suppresses vibration when the rotation of the engine 2 passes through the resonance region by shortening the time during which the rotation of the engine 2 stays in the resonance region.

In the descent promotion control, the torque in the direction opposite to the torque in the forward direction applied to the rotation direction of the crankshaft of the engine 2 is applied to the crankshaft from the ISG 20. As the torque applied to the crankshaft as the torque in the reverse direction from the ISG20, the regenerative torque of the ISG20 by making the ISG20 function as a generator or the torque in the reverse direction to the crankshaft is driven by force. It is possible to use the power running torque when the crank is made to run.

In the descent promotion control, since the torque in the opposite direction is applied from the ISG 20 to the crankshaft as described above, the decrease speed of the engine rotation speed becomes large, and the decrease of the engine rotation speed is promoted.

The predetermined execution condition is that, when the descent promotion control is executed, the oil pump 50 is driven by the inertial force of the engine 2 until the rotation of the engine 2 is stopped, and the gear ratio γ of the CVT 4 is set as the target gear ratio. It is possible to change to γtgt.

Specifically, in this embodiment, it is a predetermined execution condition that the gear ratio γ of the CVT 4 becomes a predetermined gear ratio γth or more during the rotation descent period. The predetermined gear ratio γth sets the gear ratio γ of the CVT 4 as the target gear ratio γtgt by driving the oil pump 50 by the inertial force of the engine 2 between the time when the descent promotion control is executed and the time when the rotation of the engine 2 is stopped. It is a gear ratio that can be changed to.

The predetermined gear ratio γth is a matching value experimentally obtained in advance, and may be a fixed value or a variable according to the state of the vehicle 1 such as the vehicle speed. Further, the predetermined gear ratio γth may be a different value depending on whether the output of the ISG 20 is not limited or limited.

When the output of the ISG20 is limited, a large torque in the opposite direction is not applied from the ISG20 to the crankshaft as compared with the case where the output of the ISG20 is not limited. The rate of decrease in speed becomes smaller. Therefore, as compared with the case where the output of the ISG 20 is not limited, the inertial force of the engine 2 for driving the oil pump 50 becomes large, and the descent promotion control is executed until the rotation of the engine 2 is stopped. Time will be longer.

As a result, even if the timing of executing the descent promotion control is advanced, the gear ratio γ of the CVT 4 can be changed to the target gear ratio γtgt between the execution of the descent promotion control and the stop of the rotation of the engine 2. It becomes.

Therefore, when the output of the ISG 20 is limited, the predetermined gear ratio γth is preferably set to a smaller gear ratio than when the output of the ISG 20 is not limited. As a result, when the output of the ISG 20 is restricted, the timing of executing the descent promotion control can be advanced as compared with the case where the output of the ISG 20 is not restricted.

As a result, even when the output of the ISG 20 is limited, the gear ratio γ of the CVT 4 is targeted while shortening the time until the rotation of the engine 2 is stopped by advancing the timing of executing the descent promotion control. The gear ratio can be changed to γtgt.

In this embodiment, the target gear ratio γtgt is a gear ratio that is larger than the predetermined gear ratio γth and is suitable when the vehicle 1 starts or the vehicle speed is low. The target gear ratio γtgt may be a gear ratio smaller than the predetermined gear ratio γth. For example, when an upshift request is made during execution of descent promotion control, it is possible to shift the gear ratio γ of the CVT 4 to a gear ratio smaller than a predetermined gear ratio γth by the inertial force of the engine 2. In such a case, the target gear ratio γtgt can be set as a gear ratio smaller than the predetermined gear ratio γth.

Next, with reference to FIG. 3, the flow of post-engine stop processing executed by the ECU 9 will be described. The post-engine stop processing shown in FIG. 3 is executed when a predetermined engine stop condition is satisfied.

As shown in FIG. 3, when a predetermined engine stop condition is satisfied in step S1, the ECU 9 stops fuel injection to the engine 2 (step S2).

After that, the ECU 9 determines whether or not the engine rotation speed RPM calculated based on the detection information of the crank angle sensor 44 is 1st_RPM or less, which is the upper limit of the resonance region of the engine 2 (step S3).

When the ECU 9 determines in step S3 that the engine rotation speed RPM is not 1st_RPM or less, the ECU 9 executes the process of step S3 again.

When the ECU 9 determines in step S3 that the engine rotation speed RPM is 1st_RPM or less, it determines whether or not a predetermined execution condition related to descent promotion control is satisfied (step S4). In this embodiment, as described above, the ECU 9 determines whether or not the gear ratio γ of the CVT 4 is equal to or greater than the predetermined gear ratio γth.

When the ECU 9 determines in step S4 that the predetermined execution condition related to the descent promotion control is not satisfied, the ECU 9 returns the process to step S3.

When it is determined in step S4 that the predetermined execution conditions related to the descent promotion control are satisfied, the ECU 9 executes the descent promotion control (step S5).

After that, the ECU 9 determines whether or not the engine rotation speed RPM calculated based on the detection information of the crank angle sensor 44 is lower than the lower limit of the resonance region of the engine 2, 2nd_RPM (step S6).

When the ECU 9 determines in step S6 that the engine rotation speed RPM is not lower than 2nd_RPM, the ECU 9 executes the process of step S6 again.

When the ECU 9 determines in step S6 that the engine rotation speed RPM is lower than 2nd_RPM, the ECU 9 stops the descent promotion control that started execution in step S5 (step S7), and ends the post-engine processing. The descent promotion control may be continued until the engine speed RPM becomes "0".

Next, with reference to FIG. 4, the transitions of the gear ratio γ, the oil pressure P, and the engine rotation speed RPM when the descent promotion control is executed in the vehicle 1 of the present embodiment will be described. The oil pressure P is the oil pressure supplied to the input side hydraulic cylinder 15 and the output side hydraulic cylinder 16.

As shown in FIG. 4, when the fuel injection to the engine 2 is stopped at the time t2 after the predetermined engine stop condition is satisfied at the time t1, the engine rotation speed RPM starts to gradually decrease. Along with this, the oil pressure P supplied to the input side hydraulic cylinder 15 and the output side hydraulic cylinder 16 also begins to gradually decrease. The gear ratio γ gradually increases until time t4, which will be described later, that is, the gear ratio gradually shifts to the gear ratio on the low speed side.

Next, at time t3, when the gear ratio γ reaches a predetermined gear ratio γth, the ECU 9 executes descent promotion control. After the time t3 during which the descent promotion control is being executed, the engine rotation speed RPM decreases in a state where the reduction speed is larger than the engine rotation speed when the descent promotion control shown by the solid line in FIG. 4 is not executed. Along with this, the oil pressure P supplied to the input side hydraulic cylinder 15 and the output side hydraulic cylinder 16 also decreases at a higher rate of decrease than the oil pressure when the descent promotion control shown by the solid line in FIG. 4 is not executed.

After that, at time t4, when the engine rotation speed RPM reaches "0", that is, when the rotation of the engine 2 is stopped, the oil pressure P supplied to the input side hydraulic cylinder 15 and the output side hydraulic cylinder 16 also becomes "0", and the speed is changed. The ratio γ reaches the target gear ratio γtgt. The engine rotation speed RPM seems to decrease at a predetermined decrease rate between the time t3 and the time t4, but when the engine rotation speed PRM falls below 2nd_RPM, the descent promotion control stops and the decrease rate decreases. It becomes gradual.

In this embodiment, as shown in FIG. 4, the gear ratio γ of the CVT 4 is changed to the target gear ratio γtgt between the time when the descent promotion control is executed and the time t4 when the rotation of the engine 2 is stopped.

Further, when the output of the ISG 20 is restricted, as shown in FIG. 5, the descent promotion control is executed at an earlier timing than when the output of the ISG 20 is not restricted. The times t1, t2, t3 and t4 in FIG. 5 have the same timings as the times t1, t2, t3 and t4 shown in FIG.

Specifically, when the output of the ISG20 is restricted, the predetermined gear ratio γth is set to a smaller gear ratio γth_lim as compared with the case where the output of the ISG20 is not restricted. The descent promotion control is executed by the ECU 9 at a time t3'at a timing earlier than t3.

After time t3', the engine speed RPM is lower than the decrease speed of the engine speed RPM (shown by the broken line in FIG. 5) when the output of the ISG 20 is not restricted, as shown by the fine solid line in FIG. Gradually decreases at a small rate of decrease. Along with this, the oil pressure P supplied to the input side hydraulic cylinder 15 and the output side hydraulic cylinder 16 is also the oil pressure P when the output of the ISG 20 is not restricted, as shown by a fine solid line in FIG. 5 (in FIG. 5). , Shown by a broken line) Gradually decreases at a decrease rate smaller than the decrease rate.

After that, when the engine rotation speed RPM reaches "0", that is, when the rotation of the engine 2 is stopped at the time t4'at a timing later than the time t4 shown in FIG. 4, the input side hydraulic cylinder 15 and the output side hydraulic cylinder 16 are set. The supplied hydraulic pressure P is also "0".

As shown by the solid line in FIG. 5, the gear ratio γ is the gear ratio γ when the output of the ISG 20 is not restricted after the time t3'when the descent promotion control is started (indicated by the broken line in FIG. 5). It gradually increases toward the target gear ratio γtgt at a slower speed, and reaches the target gear ratio γtgt at time t4'.

As described above, the vehicle control device according to the present embodiment indicates that the predetermined execution condition is satisfied during the rotation descent period from the establishment of the predetermined engine stop condition to the stop of the rotation of the engine 2. The condition is configured to perform descent promotion control.

Further, the predetermined execution condition is that, when the descent promotion control is executed, the oil pump 50 is driven by the inertial force of the engine 2 until the rotation of the engine 2 is stopped, and the gear ratio γ of the CVT 4 is targeted. It is possible to change the gear ratio γtgt, and specifically, the gear ratio γ of the CVT 4 becomes a predetermined gear ratio γth or more during the rotation descent period.

Further, the predetermined gear ratio γth sets the gear ratio γ of the CVT 4 as the target shift by driving the oil pump 50 by the inertial force of the engine 2 between the time when the descent promotion control is executed and the time when the rotation of the engine 2 is stopped. It is a gear ratio that can be changed to the ratio γtgt.

As described above, the vehicle control device according to the present embodiment executes the descent promotion control on the condition that the gear ratio γ of the CVT 4 can be changed to the target gear ratio γtgt. Even if there is, the gear ratio γ of the CVT 4 can be changed to the target gear ratio γtgt, which is a desired gear ratio, until the rotation of the engine 2 is stopped. This makes it possible to prevent the responsiveness of acceleration or starting after restarting the engine 2 from deteriorating.

Further, in the vehicle control device according to the present embodiment, the target gear ratio γtgt is larger than the predetermined gear ratio γth and is a gear ratio suitable for starting or at a low vehicle speed. As a result, the gear ratio γ of the CVT 4 when the descent promotion control is executed to stop the rotation of the engine 2 can be set to a gear ratio suitable for starting or at a low vehicle speed.

Therefore, the vehicle control device according to the present embodiment is suitable for the gear ratio γ of the CVT 4 when starting or accelerating from the gear ratio for medium vehicle speed or high vehicle speed when restarting the engine 2 and starting or accelerating. It is not necessary to change the gear ratio, and it is possible to improve the responsiveness of acceleration or start after restarting the engine 2.

In this embodiment, the descent promotion control has been described as a control for promoting a decrease in the engine rotation speed so that the rotation of the engine 2 passes through the resonance region of the engine 2 in a short time, but the present invention is limited to this. Instead, it may be executed when it is desired to stop the rotation of the engine 2 at an early stage.

Further, in the present embodiment, the predetermined execution condition of the descent promotion control is that the gear ratio γ of the CVT 4 becomes equal to or higher than the predetermined gear ratio γth during the rotation descent period, but the present invention is not limited to this, and for example, rotation. The fact that the oil pressure P detected by the oil pressure sensor 48 during the descent period becomes equal to or less than the predetermined oil pressure Pth may be set as a predetermined execution condition of the descent promotion control.

In this case, as shown in FIG. 6, when the fuel injection to the engine 2 is stopped at the time t12 after the predetermined engine stop condition is satisfied at the time t11, the engine rotation speed RPM starts to gradually decrease. Along with this, the oil pressure P supplied to the input side hydraulic cylinder 15 and the output side hydraulic cylinder 16 also begins to gradually decrease. The gear ratio γ gradually increases until time t14, which will be described later, that is, the gear ratio gradually shifts to the gear ratio on the low speed side.

Next, at time t13, when the oil pressure P reaches a predetermined oil pressure Pth, the ECU 9 executes descent promotion control. After the time t13 when the descent promotion control is being executed, the engine rotation speed RPM decreases in a state where the reduction speed is larger than the engine rotation speed when the descent promotion control shown by the solid line in FIG. 6 is not executed. Along with this, the oil pressure P supplied to the input side hydraulic cylinder 15 and the output side hydraulic cylinder 16 also decreases at a higher rate of decrease than the oil pressure when the descent promotion control shown by the solid line in FIG. 6 is not executed.

After that, at time t14, when the engine rotation speed RPM reaches "0", that is, when the rotation of the engine 2 is stopped, the oil pressure P supplied to the input side hydraulic cylinder 15 and the output side hydraulic cylinder 16 also becomes "0", and the speed is changed. The ratio γ reaches the target gear ratio γtgt.

As described above, even in the example shown in FIG. 6, the gear ratio γ of the CVT 4 is changed to the target gear ratio γtgt between the time when the descent promotion control is executed and the time t14 when the rotation of the engine 2 is stopped. ..

The predetermined flood control Pth drives the oil pump 50 by the inertial force of the engine 2 from the execution of the descent promotion control to the stop of the rotation of the engine 2 to set the gear ratio γ of the CVT 4 to the target gear ratio γtgt. It is a changeable oil pressure. The predetermined oil pressure Pth is a conforming value experimentally obtained in advance, may be a fixed value, or may be a variable according to the state of the vehicle 1 such as the vehicle speed. The discharge pressure of the oil pump 50 may be used as the oil pressure P.

(Second Example)
Next, the vehicle control device according to the second embodiment will be described with reference to FIGS. 7 to 9.

As shown in FIG. 7, the vehicle 1 of the present embodiment has an auxiliary drive unit 21 capable of performing a speed change operation in the CVT 4 in addition to the oil pump 50, and a battery (not shown) that is a drive source of the auxiliary drive unit 21. Although it differs from the first embodiment in that it has and, other configurations are the same as those of the first embodiment.

As the auxiliary drive unit 21 of this embodiment, for example, a starter motor provided separately from the ISG 20 or a dedicated motor capable of applying a rotational force to the crankshaft of the engine 2 can be used. By making the ISG 20 function as an electric motor, the ISG 20 may be used as the auxiliary drive unit 21.

The auxiliary drive unit 21 drives the oil pump 50 by rotating the crankshaft of the engine 2 with the electric power supplied from the battery for the auxiliary drive unit 21. The battery for the auxiliary drive unit 21 is a battery different from the battery that supplies power to the ISG 20.

Next, with reference to FIG. 8, the flow of post-engine stop processing executed by the ECU 9 will be described. The post-engine stop processing shown in FIG. 8 is executed when a predetermined engine stop condition is satisfied.

As shown in FIG. 8, when a predetermined engine stop condition is satisfied in step S21, the ECU 9 stops fuel injection to the engine 2 (step S22).

After that, the ECU 9 determines whether or not the engine rotation speed RPM calculated based on the detection information of the crank angle sensor 44 is 1st_RPM or less, which is the upper limit of the resonance region of the engine 2 (step S23).

When the ECU 9 determines in step S23 that the engine speed RPM is not 1st_RPM or less, the ECU 9 executes the process of step S23 again.

When the ECU 9 determines in step S23 that the engine rotation speed RPM is 1st_RPM or less, it determines whether or not a predetermined execution condition related to descent promotion control is satisfied (step S24).

In this embodiment, the predetermined execution condition is that, when the descent promotion control is executed, the oil pump 50 is driven by the inertial force of the engine 2 until the rotation of the engine 2 is stopped, and the gear ratio of the CVT 4 is changed. It is possible to change γ to the target gear ratio γtgt.

In this embodiment, whether or not the predetermined execution condition is satisfied is determined based on the result of the shiftability determination shown in FIG. 9, which will be described later. In addition, the gear ratio γ of the CVT 4 became equal to or higher than the predetermined gear ratio γth during the rotation descent period, or the oil pressure P detected by the oil pressure sensor 48 during the rotation descent period became equal to or less than the predetermined oil pressure Pth. This may be a predetermined execution condition in this embodiment.

When the ECU 9 determines in step S24 that the predetermined execution condition related to the descent promotion control is not satisfied, it determines whether or not it is possible to bring the gear ratio γ of the CVT 4 closer to the target gear ratio γtgt (step). S29).

The ECU 9 can bring the gear ratio γ closer to the target gear ratio γtgt, for example, when it is presumed that the engine rotation speed RPM gradually decreases and it takes a relatively long time for the engine 2 to stop rotating. It can be determined that there is. On the other hand, the ECU 9 brings the gear ratio γ closer to the target gear ratio γtgt, for example, when it is presumed that a long time cannot be secured until the rotation of the engine 2 stops due to a sudden decrease in the engine rotation speed RPM. Can be determined not to be possible.

When the ECU 9 determines in step S29 that the gear ratio γ of the CVT 4 can be brought close to the target gear ratio γtgt, the ECU 9 continuously performs a shifting operation to bring the gear ratio γ closer to the target gear ratio γtgt (step). S30), the process is returned to step S24. As a result, the gear ratio γ is changed to the target gear ratio γtgt until the predetermined execution condition related to the descent promotion control is satisfied, that is, until the rotation of the engine 2 is stopped when the descent promotion control is executed. Until it becomes possible, the gear ratio γ can be brought close to the target gear ratio γtgt without executing the descent promotion control.

When the ECU 9 determines in step S29 that it is not possible to bring the gear ratio γ of the CVT 4 closer to the target gear ratio γtgt, the ECU 9 determines whether or not the descent limit control can be executed (step S31).

The descent limit control is a control that limits the regenerative torque or the power running torque of the ISG 20 that is applied to the crankshaft as a torque in the opposite direction in the descent promotion control. Specifically, the ECU 9 reduces the regenerative torque or power running torque of the ISG 20 in the descent promotion control as compared with the case where the descent limit control is not executed. As a result, the reduction speed of the engine rotation speed in the descent promotion control is reduced, that is, limited, so that the time until the rotation of the engine 2 is stopped becomes long. As a result, when the descent limit control is executed, the period from the execution of the descent promotion control to the stop of the rotation of the engine 2 becomes longer, and the gear ratio γ of the CVT 4 is targeted by the time the rotation of the engine 2 stops. It is possible to change the gear ratio to γtgt or approach the target gear ratio γtgt.

The ECU 9 can determine that the descent limit control cannot be executed when the remaining capacity of the battery that supplies power to the ISG 20 is small and the required discharge power for the battery is high. In such a case, it is determined that the descent limit control is not feasible because there is a possibility that the battery that supplies power to the ISG 20 cannot supply power to other in-vehicle devices. On the other hand, the ECU 9 can determine that the drop limit control can be executed when the remaining capacity of the battery that supplies power to the ISG 20 is large or the required discharge power for the battery is low.

When the ECU 9 determines in step S31 that the descent limit control can be executed, the ECU 9 executes the descent limit control (step S32) and shifts the process to step S25.

When the ECU 9 determines in step S31 that the descent limit control cannot be executed, the process shifts to step S33.

When it is determined in step S24 that the predetermined execution conditions related to the descent promotion control are satisfied, the ECU 9 executes the descent promotion control (step S25).

After that, the ECU 9 determines whether or not the engine rotation speed RPM calculated based on the detection information of the crank angle sensor 44 is lower than the lower limit of the resonance region of the engine 2, 2nd_RPM (step S26).

When the ECU 9 determines in step S26 that the engine rotation speed RPM is not lower than 2nd_RPM, the ECU 9 executes the process of step S26 again.

When the ECU 9 determines in step S26 that the engine rotation speed RPM is lower than 2nd_RPM, the ECU 9 stops the descent promotion control that started execution in step S25 (step S27). The descent promotion control may be continued until the engine speed RPM becomes "0".

After that, the ECU 9 determines whether or not the gear ratio γ of the CVT 4 has been changed to the target gear ratio γtgt (step S28). When the ECU 9 determines in step S28 that the gear ratio γ of the CVT 4 has been changed to the target gear ratio γtgt, the ECU 9 ends the post-engine processing.

When the ECU 9 determines in step S28 that the gear ratio γ of the CVT 4 has not been changed to the target gear ratio γtgt, the process shifts to step S33.

In step S33, the ECU 9 drives the auxiliary drive unit 21 to perform a shifting operation so that the gear ratio γ of the CVT 4 becomes the target gear ratio γtgt. After that, the ECU 9 ends the processing after stopping the engine.

Next, with reference to FIG. 9, the flow of the shiftability determination process executed in the process of step S24 of the engine stop post-processing shown in FIG. 8 will be described.

As shown in FIG. 9, the ECU 9 calculates the degree of first engine descent from the traveling load including the gear ratio γ, the engine rotation speed RPM, the vehicle speed, and the road gradient (step S41). The traveling load including the road gradient can be obtained based on, for example, map information or road information obtained from a car navigation device, detection information of an acceleration sensor (not shown), or the like.

The ROM of the ECU 9 stores a map in which the relationship between the gear ratio γ, the engine rotation speed RPM, the vehicle speed, the running load, and the degree of descent of the first engine is experimentally obtained in advance. Based on the map, the ECU 9 can calculate the degree of descent of the first engine from the traveling load including the vehicle speed and the road gradient. The first engine descent degree is the decrease rate of the engine rotation speed RPM when the descent promotion control is not executed.

Next, the ECU 9 calculates the output torque of the ISG 20 from the remaining capacity of the battery that supplies power to the ISG 20, the battery temperature of the battery, the substrate temperature, and the winding temperature (step S42).

The remaining capacity of the battery can be determined based on the detection information of the battery sensor (not shown). The battery temperature is detected by a battery temperature sensor (not shown). The substrate temperature is the temperature of the substrate for controlling the ISG20, and may be directly detected by a sensor such as a thermistor or estimated from the winding temperature, for example. The winding temperature is the temperature of the winding of the ISG20, and may be detected directly by a sensor such as a thermistor, or may be calculated based on the resistance value of the winding.

The ROM of the ECU 9 stores a map in which the remaining capacity of the battery that supplies power to the ISG 20, the battery temperature of the battery, the substrate temperature, the winding temperature, and the relationship between the output torque of the ISG 20 are experimentally obtained in advance. There is. The output torque of the ISG 20 is the regenerative torque or power running torque of the ISG 20 applied to the crankshaft as a torque in the opposite direction. Based on the map, the ECU 9 can calculate the output torque of the ISG 20 from the remaining capacity of the battery that supplies power to the ISG 20, the battery temperature of the battery, the substrate temperature, and the winding temperature.

Next, the ECU 9 calculates the degree of descent of the second engine during descent promotion control from the degree of descent of the first engine and the outputable torque of the ISG 20 (step S43). The second engine descent degree is the decrease rate of the engine rotation speed RPM when the descent promotion control is executed. That is, the second engine descent degree is calculated based on the first engine descent degree when the descent promotion control is not executed and the output torque of the ISG 20.

The ROM of the ECU 9 stores a map in which the relationship between the first engine descent degree and the output torque of the ISG 20 and the second engine descent degree is experimentally obtained in advance. Based on the map, the ECU 9 can calculate the degree of descent of the second engine during descent promotion control from the degree of descent of the first engine and the outputable torque of the ISG 20.

Next, the ECU 9 determines whether or not the gear ratio γ of the CVT 4 can be changed to the target gear ratio γtgt between the execution of the descent promotion control and the stop of the rotation of the engine 2 based on the degree of descent of the second engine. (Step S44).

As described above, the vehicle control device according to the present embodiment indicates that the predetermined execution condition is satisfied during the rotation descent period from the establishment of the predetermined engine stop condition to the stop of the rotation of the engine 2. The condition is configured to perform descent promotion control.

As described above, the vehicle control device according to the present embodiment executes the descent promotion control on the condition that the gear ratio γ of the CVT 4 can be changed to the target gear ratio γtgt. Even if there is, the gear ratio γ of the CVT 4 can be changed to the target gear ratio γtgt, which is a desired gear ratio, until the rotation of the engine 2 is stopped. This makes it possible to prevent the responsiveness of acceleration or starting after restarting the engine 2 from deteriorating.

Further, the vehicle control device according to the present embodiment targets the gear ratio γ of the CVT 4 even if the oil pump 50 is driven until the rotation of the engine 2 is stopped when the descent promotion control is executed. When the gear ratio γtgt cannot be changed, the oil pump 50 is driven to bring the gear ratio γ closer to the target gear ratio γtgt before executing the descent promotion control.

With this configuration, the vehicle control device according to the present embodiment does not execute the descent promotion control until the gear ratio γ approaches the target gear ratio γtgt. Therefore, the gear ratio γ is set by executing the descent promotion control at an inappropriate timing. It is possible to suppress a situation in which the target gear ratio γtgt cannot be changed.

Further, the vehicle control device according to the present embodiment targets the gear ratio γ of the CVT 4 even if the oil pump 50 is driven until the rotation of the engine 2 is stopped when the descent promotion control is executed. When the gear ratio γtgt cannot be changed, the descent limit control is configured to limit the decrease rate of the engine rotation speed RPM during the execution of the descent promotion control.

With this configuration, the vehicle control device according to the present embodiment can reduce the decrease speed of the engine rotation speed in the descent promotion control as compared with the case where the descent limit control is not executed, and the rotation of the engine 2 is stopped. You can lengthen the time it takes to do this. As a result, the gear ratio γ of the CVT 4 can be changed to the target gear ratio γtgt or approached to the target gear ratio γtgt by the time the rotation of the engine 2 is stopped. As a result, when the engine 2 is stopped, at least the gear ratio γ of the CVT 4 can be kept close to the target gear ratio γtgt, so that it is possible to prevent the responsiveness of acceleration or starting after the restart of the engine 2 from deteriorating. Can be done.

Further, the vehicle control device according to the present embodiment targets the gear ratio γ of the CVT 4 even if the oil pump 50 is driven until the rotation of the engine 2 is stopped when the descent promotion control is executed. When the gear ratio γtgt cannot be changed, the auxiliary drive unit 21 is driven to change the gear ratio γ to the target gear ratio γtgt.

With this configuration, the vehicle control device according to the present embodiment can surely change the gear ratio γ to the target gear ratio γtgt even when the descent promotion control is executed.

Although the embodiments of the present invention have been disclosed, it is clear that some skilled in the art can make changes without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

In each of the above-described embodiments, a vehicle using an internal combustion engine as an engine has been described, but a vehicle using a motor generator that generates power by electric power of a battery instead of the internal combustion engine may be used as the engine.

Further, in each of the above-described embodiments, an example in which the CVT 4 is used as the transmission has been described, but the transmission is not limited to the CVT, and for example, the transmission operation is performed by the hydraulic pressure of the oil pump 50 driven by the power of the engine 2. It may be a stepped automatic transmission, a transmission using a planetary gear mechanism, or the like.

When a stepped automatic transmission is used as the transmission, when the output of the ISG 20 is limited, it is preferable to limit the skip shift such that one or more gears are skipped. As a result, in the stepped automatic transmission, the descent promotion control cannot be executed by skipping the shift gear corresponding to the gear ratio smaller than that in the case where the output of the ISG 20 is not limited. The situation can be prevented.

Further, the vehicle 1 of each of the above-described embodiments may be provided with a plurality of traveling modes having different shifting conditions, and one of the traveling modes may be selectable. In this case, at least one of the predetermined gear ratio γth and the target gear ratio γtgt is changed according to the selected traveling mode.

Therefore, at least one of the predetermined gear ratio γth and the target gear ratio γtgt is changed according to the gear ratio and the gear shift map of the traveling mode, so that the desired gear ratio for shifting during the descent promotion control is set according to the traveling mode. Can be considered. For example, when the driving mode is the 2nd speed start mode in which the vehicle starts at a gear ratio smaller than the gear ratio equivalent to the 1st gear, which is the normal gear ratio for starting, the target gear ratio γtgt is the gear ratio corresponding to the 2nd gear. Set to.

Further, in each of the above-described embodiments, the gear ratio γ is set by setting the execution condition of the descent promotion control to be such that the gear ratio γ is equal to or higher than the predetermined gear ratio γth and the oil pressure P reaches the predetermined oil pressure Pth. The certainty of shifting to the target gear ratio γtgt may be increased.

Further, in each of the above-described embodiments, when the planetary gear mechanism 6 is used as an auxiliary transmission, the present invention can also be applied to the planetary gear mechanism 6 used as an auxiliary transmission.

1 Vehicle 2 Engine 4 CVT (Transmission)
5 Hydraulic circuit (transmission device, hydraulic system)
9 ECU
20 ISG (motor)
21 Auxiliary drive unit 41 Accelerator opening sensor 42 Vehicle speed sensor 43 Shift position sensor 44 Crank angle sensor 45 Brake sensor 46 Primary pulley speed sensor 47 Secondary pulley speed sensor 48 Hydraulic sensor 50 Oil pump (transmission device, hydraulic device)
100 Control unit γ Gear ratio γth Predetermined gear ratio γtgt Target gear ratio P Oil pressure Pth Predetermined oil pressure

Claims (10)

With the engine
A transmission that shifts the rotation of the engine and outputs it,
A transmission that performs a shifting operation that changes the gear ratio of the transmission, and a transmission that performs a shifting operation.
A motor capable of transmitting power to the engine is provided.
The transmission is a vehicle control device driven by the power of the engine.
A control unit capable of executing descent promotion control for promoting a decrease in the rotation of the engine by the motor during a period from the establishment of a predetermined engine stop condition to the stop of the rotation of the engine is provided.
The control unit executes the descent promotion control on condition that a predetermined execution condition is satisfied.
Under the predetermined execution condition, when the descent promotion control is executed, the transmission gear can be driven to change the gear ratio of the transmission to the target gear ratio until the rotation of the engine is stopped. A vehicle control device characterized by being. The predetermined execution condition is that the gear ratio of the transmission becomes equal to or higher than the predetermined gear ratio during the period from the establishment of the predetermined engine stop condition to the stop of the rotation of the engine. The vehicle control device according to claim 1. The predetermined gear ratio sets the gear ratio of the transmission to the target by driving the transmission by the inertial force of the engine between the time when the descent promotion control is executed and the time when the rotation of the engine is stopped. The vehicle control device according to claim 2, wherein the gear ratio can be changed to a gear ratio. The vehicle control device according to claim 2 or 3, wherein the target gear ratio is larger than the predetermined gear ratio and is a gear ratio suitable for starting or at a low vehicle speed. A second to claim, wherein when the output of the motor is limited, the predetermined gear ratio is set to a smaller gear ratio as compared with the case where the output of the motor is not limited. The vehicle control device according to any one of 4. The transmission is a hydraulic device driven by the power of the engine.
The hydraulic device is configured to perform a shifting operation by hydraulic pressure.
The predetermined execution condition is characterized in that the oil pressure reaches the predetermined oil pressure during the period from the establishment of the predetermined engine stop condition to the stoppage of the rotation of the engine. The vehicle control device according to 1. The predetermined hydraulic pressure drives the hydraulic system by the inertial force of the engine between the time when the descent promotion control is executed and the time when the rotation of the engine is stopped, and the gear ratio of the transmission is set to the target speed change. The vehicle control device according to claim 6, wherein the oil pressure is changeable to a ratio. When the descent promotion control is executed, the control unit cannot change the gear ratio of the transmission to the target gear ratio even if the transmission is driven until the rotation of the engine is stopped. In this case, any one of claims 1 to 7, wherein the transmission is driven to bring the gear ratio of the transmission closer to the target gear ratio before the descent promotion control is executed. The vehicle control device described. When the descent promotion control is executed, the control unit cannot change the gear ratio of the transmission to the target gear ratio even if the transmission is driven until the rotation of the engine is stopped. In this case, the vehicle control device according to any one of claims 1 to 7, wherein the reduction speed of the rotation of the engine during execution of the descent promotion control is limited. The vehicle includes an auxiliary drive unit capable of driving the transmission in addition to the engine.
When the descent promotion control is executed, the control unit cannot change the gear ratio of the transmission to the target gear ratio even if the transmission is driven until the rotation of the engine is stopped. The vehicle control device according to any one of claims 1 to 7, wherein the auxiliary drive unit is driven to change the gear ratio of the transmission to a target gear ratio.

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