JP2021098485A - Control device of hybrid vehicle - Google Patents

Abstract

To improve energy efficiency and make both excellent riding comfort and driving force-responsiveness compatible.SOLUTION: A control device of a hybrid vehicle comprises a start-up clutch and an automatic transmission having a plurality of engagement mechanisms, and can set an EV travel mode in which the vehicle travels only by output of a motor and a parallel HV travel mode in which the vehicle travels at least by output of an engine. In the EV travel mode, the start-up clutch is made to engage and torque transmissibility of at least one engagement mechanism is decreased. In the parallel HV travel mode, the start-up clutch is made to engage and at least two engagement mechanisms are made to engage. When the EV transfer mode is transferred to the parallel HV travel mode, torque transmissibility of the start-up clutch is decreased once, and the torque transmissibility of the engagement mechanism is increased, and after the engagement mechanism is made to engage, the start-up clutch is made to engage.SELECTED DRAWING: Figure 4

Description

The present invention relates to a control device for a hybrid vehicle capable of switching between an EV traveling mode using a motor as a driving force source and at least a parallel HV traveling mode using an engine as a driving force source.

Patent Document 1 describes a hybrid drive device for a vehicle including an engine, a first motor, a second motor, a transmission, and a start clutch. The first motor is directly connected to the engine. The second motor outputs a driving torque as a driving force source to drive the driving wheels. The transmission shifts the number of revolutions of the engine and transmits the output torque of the engine to the drive wheels side. The start clutch selectively disengages power transmission between the engine and the first motor and the drive wheels. Further, Patent Document 1 also discloses a gear train of a hybrid vehicle including an engine, a starter motor (first motor), a rear drive motor (second motor), an automatic transmission, and a start clutch. The starter motor cranks the engine when it starts. The rear drive motor is incorporated in the rear wheel drive device and drives the rear wheels via a gear mechanism. The automatic transmission is a stepped transmission having a planetary gear mechanism and a plurality of engaging mechanisms, and is arranged between the engine and the drive wheels on the front wheel side. The start clutch is located between the engine and the automatic transmission.

The hybrid vehicle described in Patent Document 1 has an EV traveling mode in which the start clutch is released and the second motor (rear drive motor) is used as a driving force source to engage the start clutch to drive at least the engine. It is possible to switch the driving mode between the HEV driving mode in which the vehicle travels as a power source. Then, in the hybrid vehicle described in Patent Document 1, the first transition mode in which the engine is cranked by the first motor, the engine is ignited, the engine is started, and then the start clutch is engaged, and the first motor After cranking the engine with, and engaging the start clutch, the driving mode is switched in two transition modes, that is, the second transition mode in which the engine is ignited and the engine is started. In the first transition mode, since the start clutch is engaged after the engine is started, the torque fluctuation at the time of starting the engine does not affect the driving force. Therefore, it is possible to suppress the occurrence of shock and discomfort caused by unintended fluctuations in the driving force, and to secure a good ride quality. On the other hand, in the second shift mode, since the engine is started after the start clutch is engaged, the synchronous control when the start clutch is engaged can be quickly executed without being affected by the engine torque. Therefore, in particular, when shifting from the EV driving mode to the HEV driving mode, the transition of the driving mode can be executed quickly, and a large driving force can be obtained with good responsiveness. Therefore, when the driver desires to drive with an emphasis on the power performance of the vehicle, the transition of the travel mode is performed in the second transition mode.

Japanese Patent No. 5492400

As described above, in the hybrid drive device described in Patent Document 1, when the driving mode is shifted between the EV driving mode and the HEV driving mode, there are two types of transitions, the first transition mode and the second transition mode. By properly using the modes, it is possible to achieve both ensuring ride comfort and improving driving force responsiveness. However, in the case of a hybrid vehicle equipped with a stepped automatic transmission having a plurality of engaging mechanisms as described in Patent Document 1, the inside of the automatic transmission is in the EV traveling mode. If a plurality of engaging mechanisms are always engaged, a drag loss occurs in the automatic transmission, and the energy efficiency of the hybrid vehicle is lowered. In order to prevent such a decrease in energy efficiency of the hybrid vehicle, when traveling in the EV driving mode, by releasing the engagement mechanism in the automatic transmission together with the starting clutch, the drag loss as described above can be reduced. Occurrence can be avoided. However, in that case, when shifting from the EV traveling mode to the HEV traveling mode (that is, the parallel HV traveling mode), both the starting clutch and the engaging mechanism in the automatic transmission must be engaged. Therefore, it takes time until the power can be transmitted between the engine and the driving wheels, and the driving force responsiveness of the hybrid vehicle is lowered. In addition, there is a possibility that the engagement mechanism in the automatic transmission operates with the start clutch engaged, and in that case, a shock occurs when the engagement mechanism in the automatic transmission operates, and the vehicle operates. There is a risk of giving a sense of discomfort to people and occupants.

In this way, for hybrid vehicles that switch between EV driving mode and parallel HV driving mode, both good riding comfort and driving force responsiveness are achieved without lowering the energy efficiency of the hybrid vehicle. There was still room for improvement to make it happen.

The present invention has been conceived by paying attention to the above technical problems, and is intended to improve the energy efficiency of a hybrid vehicle for a hybrid vehicle that travels by switching between an EV driving mode and a parallel HV driving mode. It is an object of the present invention to provide a control device for a hybrid vehicle capable of achieving both good riding comfort and driving force responsiveness.

In order to achieve the above object, the present invention has a torque transmission rate (or transmission torque capacity) in a power transmission path between an engine, at least one motor, a drive wheel, and the engine and the drive wheel. ), An automatic transmission that is arranged between the start clutch and the drive wheels and transmits torque between the engine and the drive wheels, and the automatic transmission. A plurality of engagements provided between the input shaft and the output shaft of the transmission and capable of continuously changing the torque transmission rate (or transmission torque capacity) between the input shaft and the output shaft. An EV traveling mode in which the engine, the motor, the starting clutch, and a controller for controlling the engaging mechanism are provided and the motor is used as the driving force source, and at least the engine is used as the driving force source. In a hybrid vehicle control device capable of selectively setting a parallel HV traveling mode in which the vehicle travels as a vehicle, the automatic transmission has a predetermined speed change by engaging at least one of the two engaging mechanisms. The controller engages the start clutch (that is, the torque transmission rate of the start clutch is set to 100%) in the EV drive mode, and at least one of the above is set. The torque transmission rate of the engaging mechanism is lowered, and in the parallel HV traveling mode, the starting clutch is engaged and at least any two of the engaging mechanisms (for setting a predetermined shift stage) are engaged. When engaging (that is, setting the torque transmission rate of the engaging mechanism to 100%) and shifting from the EV traveling mode to the parallel HV traveling mode, the torque transmission rate of the starting clutch is temporarily lowered. In addition, the torque transmission rate of the engaging mechanism whose torque transmission rate is lowered in the EV traveling mode is increased, and after engaging the engaging mechanism, the torque transmission rate of the starting clutch is increased to obtain the above. It is characterized by engaging the starting clutch.

The control device for the hybrid vehicle of the present invention is provided with a start clutch in which the torque transmission rate or the transmission torque capacity is continuously variable, so that the start clutch is controlled to be in a slip-engaged state at the time of starting or at a low vehicle speed. Smooth power transmission is possible. Further, by providing an automatic transmission that shifts the engine speed and amplifies the engine torque, for example, the drive torque output by the engine can be effectively utilized when a high load is required. Further, in the control device for the hybrid vehicle of the present invention, a predetermined shift stage of the automatic transmission is set by controlling the operation of a plurality of engaging mechanisms provided inside the automatic transmission. At the same time, the power transmission in the automatic transmission can be cut off. That is, by disengaging at least one of the at least two engaging mechanisms that are engaged to set a predetermined gear, the automatic transmission is between the input shaft and the output shaft. Power transmission can be cut off. Therefore, when traveling in the EV traveling mode, the power transmission in the automatic transmission can be cut off with the start clutch engaged. Therefore, it is possible to reduce the drag loss in the automatic transmission while traveling in the EV traveling mode. Further, for example, by configuring the start clutch using the return spring, it is not necessary to maintain the start clutch in the released state by using the flood control, so that the energy consumption can be suppressed by the amount that the hydraulic pressure becomes unnecessary. Then, in the hybrid vehicle control device of the present invention, when the traveling mode is changed from the EV traveling mode to the parallel HV traveling mode, so-called replacement control of the starting clutch and the engagement mechanism of the automatic transmission is performed. Power can be transmitted with good responsiveness while suppressing torque fluctuations and clutch engagement shocks caused by the inner shuttlek inside the automatic transmission. Therefore, according to the hybrid vehicle control device of the present invention, it is possible to improve the energy efficiency of the hybrid vehicle by targeting the hybrid vehicle that travels by switching between the EV traveling mode and the parallel HV traveling mode. It is possible to achieve both good riding comfort and good driving force responsiveness.

It is a figure which shows an example of the gear train and the control system of the hybrid vehicle which is the object of control in this invention. This is an example of a collinear diagram showing the states of each element of the planetary gear mechanism in the automatic transmission of the hybrid vehicle of FIG. 1, and the state in which the automatic transmission is in the “second speed” in the “EV traveling mode” will be described. It is a figure for. It is an example of a collinear diagram showing the state of each element of the planetary gear mechanism in the automatic transmission of the hybrid vehicle of FIG. 1, and is an example of the control executed by the prior art (the automatic transmission is changed from "second speed" to "second speed". It is a figure for demonstrating (the state which carried out the engagement preparation for shifting to "1st speed"). It is a flowchart for demonstrating an example of the control executed by the control device of the hybrid vehicle of this invention. This is an example of a collinear diagram showing the state of each element of the planetary gear mechanism in the automatic transmission of the hybrid vehicle shown in FIG. It is a figure for demonstrating the state which carried out the engagement preparation for shifting to "". This is an example of a collinear diagram showing the state of each element of the planetary gear mechanism in the automatic transmission of the hybrid vehicle shown in FIG. It is a figure for demonstrating (the state of "first speed"). It is a time chart for demonstrating the behavior of each part of a hybrid vehicle when the control shown in the flowchart of FIG. 3 is executed.

An embodiment of the present invention will be described with reference to the drawings. It should be noted that the embodiments shown below are merely examples of cases where the present invention is embodied, and do not limit the present invention.

The vehicle to be controlled in the embodiment of the present invention is a hybrid vehicle using an engine and at least one motor as a driving force source. Further, the hybrid vehicle to be controlled in the embodiment of the present invention has a start clutch that changes the torque transmission rate in the power transmission path between the driving force source and the driving wheels, and torque between the engine and the driving wheels. It is equipped with an automatic transmission that transmits. The automatic transmission is provided with engaging mechanisms such as a plurality of clutches and brakes, and each engaging mechanism is operated in an engaged or disengaged state to switch a torque transmission state (shift stage). It is configured. FIG. 1 shows an example of a drive unit (drive system and control system) of a hybrid vehicle to be controlled in the embodiment of the present invention.

The hybrid vehicle (hereinafter referred to as vehicle) Ve shown in FIG. 1 includes an engine (ENG) 1, a first motor (MG1) 2, and a second motor (MG2) 3 as driving force sources. In addition, the vehicle Ve has four other main components, a drive wheel (rear wheel) 4, a drive wheel (front wheel) 5, a start clutch 6, an automatic transmission (AT) 7, a detection unit 8, and a controller (ECU). ) 9 is provided.

The engine 1 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine, and is configured to adjust the output and electrically control operating states such as start and stop. In the case of a gasoline engine, the opening degree of the throttle valve, the amount of fuel supplied or injected, the execution and stop of ignition, and the ignition timing are electrically controlled. In the case of a diesel engine, the fuel injection amount, the fuel injection timing, the opening degree of the throttle valve in the EGR system, and the like are electrically controlled.

The first motor 2 converts electrical energy into mechanical energy (or rotational energy), or converts mechanical energy (or rotational energy) into electrical energy. The first motor 2 is arranged coaxially with the engine 1 and is connected to the drive wheels 4 and 5 so as to be able to transmit power via an automatic transmission 7 and a transfer 15 described later. The first motor 2 also has a function as a generator that generates electric power by being driven by receiving the torque output by the engine 1. That is, the first motor 2 is a motor having a power generation function (so-called motor generator), and is composed of, for example, a permanent magnet type synchronous motor, an induction motor, or the like. A battery (not shown) is connected to the first motor 2 via an inverter (not shown). Therefore, the first motor 2 can function as a generator, and the electric power generated at that time can be stored in the battery. It is also possible to supply the electric power stored in the battery to the first motor 2 and make the first motor 2 function as a prime mover to output the drive torque.

The second motor 3 converts electrical energy into mechanical energy (or rotational energy) or mechanical energy (or rotational energy) into electrical energy. The second motor 3 is connected to the drive wheels (front wheels) 5 so as to be able to transmit power via a reduction gear 10 and a transmission mechanism 11 using, for example, a planetary gear mechanism. The second motor 3 also has a function as a generator that generates electric power by being driven by receiving torque from the outside. That is, the second motor 3 is a motor having a power generation function (so-called motor generator) like the first motor 2 described above, and is composed of, for example, a permanent magnet type synchronous motor, an induction motor, or the like. ing. A battery (not shown) is connected to the second motor 3 via an inverter (not shown). Therefore, the electric power stored in the battery can be supplied to the second motor 3, and the second motor 3 can function as a prime mover to output the drive torque. Further, the second motor 3 can be made to function as a generator by the torque transmitted from the drive wheels (front wheels) 5, and the regenerative power generated at that time can be stored in the battery. Further, the first motor 2 and the second motor 3 are connected to each other via an inverter so that electric power can be exchanged with each other. Therefore, for example, it is possible to directly supply the electric power generated by the first motor 2 to the second motor 3 and output the drive torque by the second motor 3.

The drive wheels (rear wheels) 4 generate the driving force of the vehicle Ve by transmitting the driving torque output from the driving force sources (engine 1 and the first motor 2). In the example shown in FIG. 1, the drive wheel (rear wheel) 4 is provided via an automatic transmission 7, a transfer 15, a rear propeller shaft 12, a rear differential gear 13, and a rear drive shaft 14, which will be described later. It is connected to a driving force source (that is, an engine 1, a first motor 2, and a second motor 3).

The drive wheels (front wheels) 5 generate the driving force of the vehicle Ve by transmitting the driving torque output from the driving force sources (engine 1, first motor 2, and second motor 3). That is, in the example shown in FIG. 1, the vehicle Ve is a four-wheel drive vehicle or an all-wheel drive vehicle that transmits drive torque to both the front wheels 5 and the rear wheels 4 to generate a driving force. Therefore, the drive wheel (front wheel) 5 is connected to the drive force source (that is, the engine 1 and the first motor 2) via the transfer 15, the front propeller shaft 16, the front differential gear 17, and the front drive shaft 18. It is connected. Further, as described above, the drive wheels (front wheels) 5 are connected to the drive force source (that is, the second motor 3) via the reduction gear 10 and the transmission mechanism 11.

The transfer 15 is a mechanism that distributes the output torque of the driving force source to the driving wheel (rear wheel) 4 side and the driving wheel (front wheel) 5 side, and is the output side of the automatic transmission 7 (right side in FIG. 1). Is located in. The rear propeller shaft 12 is connected to the output member (not shown) on the drive wheel (rear wheel) 4 side of the transfer 15, and the front propeller shaft 16 is connected to the output member (not shown) on the drive wheel (front wheel) 5 side. Are concatenated. The transfer 15 can be configured by, for example, a winding transmission mechanism using a chain or a belt, or a gear mechanism. Further, the transfer 15 includes a differential mechanism that enables differential rotation between the drive wheels (front wheels) 5 and the drive wheels (rear wheels) 4, and a differential limiting mechanism that limits the differential rotation by a friction clutch or the like. You may have it. Further, the transfer 15 is a full-time four-wheel drive mechanism including a differential mechanism provided with the above-mentioned differential limiting mechanism, or a part that selectively cuts off the transmission of torque to the drive wheel (front wheel) 5 side. It can be configured by a time four-wheel drive mechanism or the like. Further, the transfer 15 is an electronically controlled four-wheel drive capable of arbitrarily setting the distribution of the torque transmitted to the drive wheel (front wheel) 5 side and the torque transmitted to the drive wheel (rear wheel) 4 side. It may be configured by a mechanism.

The start clutch 6 selectively transmits and disengages power in a power transmission path between the engine 1 and the drive wheels 4 and 5. By releasing the start clutch 6, the engine 1 and the first motor 2 are disconnected from the drive system of the vehicle Ve. By engaging the start clutch 6, the engine 1 and the first motor 2 are connected to the drive system of the vehicle Ve. Further, the start clutch 6 is configured so that the torque transmission rate (or transmission torque capacity) can be continuously changed in the power transmission path between the engine 1 and the drive wheels 4 and 5. .. Specifically, the start clutch 6 is composed of a friction clutch capable of slip engagement (or semi-engagement). The starting clutch 6 has a torque transmission coefficient of 0% when it is completely released, and a torque transmission coefficient of 100% when it is fully engaged. Therefore, when the output torque (engine torque) of the engine 1 is transmitted to the drive wheels 4 and 5, the engagement state of the start clutch 6 is controlled to continuously change the torque transmission rate of the start clutch 6. , Smooth power transmission can be performed. Alternatively, a smooth start can be performed by the engine torque.

In the vehicle Ve, the engine 1 and the first motor 2 are connected so as to be able to transmit power as described above. Therefore, it is also possible to start or smoothly transmit power by the engine torque of the engine 1 without using the start clutch 6. For example, when the engine torque is transmitted to the drive wheels 4 and 5, the engine torque is controlled to increase or decrease by the first motor 2, so that the vehicle Ve can be started or smoothly without using the start clutch 6. Power transmission is possible. However, in the case of steady running by the engine torque at an extremely low vehicle speed (for example, about 1 km / h to 3 km / h), a differential rotation between the idle rotation speed of the engine 1 and the wheel speed occurs. In such a case, smoother power transmission can be performed by absorbing the differential rotation using the start clutch 6.

The automatic transmission 7 is arranged between the start clutch 6 and the drive wheels 4 and 5. Specifically, the automatic transmission 7 is arranged coaxially with the engine 1 and the first motor 2 on the output side (right side in FIG. 1) of the first motor 2. The automatic transmission 7 transmits the torque input from the engine 1 and the first motor 2 to the drive wheels (rear wheels) 4. The automatic transmission 7 is a mechanism capable of appropriately changing the ratio of the rotation speed (output rotation speed) of the output shaft 7b to the rotation speed (input rotation speed) of the input shaft 7a, and is a control target in the embodiment of the present invention. The vehicle Ve is composed of a stepped transmission capable of automatic control. The automatic transmission 7 has a plurality of engaging mechanisms 19 provided inside, that is, between the input shaft 7a and the output shaft 7b. In the example shown in FIG. 1, the engaging mechanism 19a and the engaging mechanism 19b are provided. Each of the engaging mechanisms 19 is configured so that the torque transmission rate (or transmission torque capacity) can be continuously changed between the input shaft 7a and the output shaft 7b. The automatic transmission 7 is configured to set a predetermined shift stage by engaging at least one of the two engaging mechanisms 19. Therefore, the automatic transmission 7 engages with at least one of the two engaging mechanisms 19, that is, by controlling the torque transmission rate of at least one of the two engaging mechanisms 19 to 100%, respectively. A predetermined shift stage is set, and power transmission is possible between the input shaft 7a and the output shaft 7b. On the other hand, by disengaging at least one of the at least two engaging mechanisms 19 that are engaged to set a predetermined speed change, that is, at least one engaging mechanism 19. By lowering the torque transmission rate, the power transmission between the input shaft 7a and the output shaft 7b is cut off.

The detection unit 8 is a device or device for acquiring various data and information necessary for controlling the vehicle Ve, and includes, for example, a power supply unit, a microcomputer, a sensor, an input / output interface, and the like. In particular, the detection unit 8 in the embodiment of the present invention controls the driving force source (engine 1, first motor 2, second motor 3), the start clutch 6, and the engagement mechanism 19 in the automatic transmission 7, respectively. Detect data to do. For example, the detection unit 8 determines the amount of operation of the vehicle speed sensor (or wheel speed sensor) 8a for detecting the vehicle speed, the engine rotation speed sensor 8b for detecting the rotation speed of the engine 1, and the accelerator pedal (not shown) by the driver. The accelerator position sensor 8c to be detected, the motor rotation speed sensor (or resolver) 8d to detect the rotation speeds of the first motor 2 and the second motor 3, respectively, and the input rotation to detect the rotation speed of the input shaft 7a of the automatic transmission 7. The number sensor 8e, the output rotation speed sensor 8f that detects the rotation speed of the output shaft 7b of the automatic transmission 7, the actuator of the start clutch 6 (not shown), and the actuator of each engagement mechanism 19 in the automatic transmission 7 It has various sensors such as a hydraulic sensor 8g that detects the hydraulic pressure supplied to (not shown). Then, the detection unit 8 is electrically connected to the controller 9 described later, and outputs an electric signal corresponding to the detection value or the calculated value of various sensors, devices / devices, etc. as described above to the controller 9 as detection data. To do.

The controller 9 is, for example, an electronic control device mainly composed of a microcomputer. In particular, the controller 9 in the embodiment of the present invention mainly includes an engine 1, a first motor 2, a second motor 3, and a start. The operation of the clutch 6 and each engaging mechanism 19 in the automatic transmission 7 is controlled. Various data detected or calculated by the detection unit 8 is input to the controller 9. The controller 9 performs a calculation using various input data, data stored in advance, a calculation formula, and the like. Then, the controller 9 outputs the calculation result as a control command signal, and engages the engine 1, the first motor 2, the second motor 3, the start clutch 6, and the automatic transmission 7 as described above. It is configured to control the operation of the mechanism 19 and the like. Although FIG. 1 shows an example in which one controller 9 is provided, a plurality of controllers 9 may be provided for each device or device to be controlled or for each control content.

The configuration (gear train) of the vehicle Ve in the embodiment of the present invention is not limited to the example shown in FIG. For example, the drive wheel (front wheel) 5 may be driven only by the second motor 3 without using the transfer 15. Alternatively, the engine 1 and the second motor 3 may be mounted as the driving force source, and the first motor 2 may not be mounted. In that case as well, the drive wheels (rear wheels) 4 may be driven only by the engine 1 and the drive wheels (front wheels) 5 may be driven only by the second motor 3 without using the transfer 15. Alternatively, the drive wheels (rear wheels) 4 are driven by the engine 1, the first motor 2, and the second motor 3, and the drive wheels (front wheels) 5 are driven by the engine 1, the first motor 2. You may. Alternatively, the drive wheels (rear wheels) 4 may be driven only by the second motor 3, and the drive wheels (front wheels) 5 may be driven only by the engine 1.

The vehicle Ve in the embodiment of the present invention is equipped with an engine 1 and at least one motor as a driving force source. In the example shown in FIG. 1, the vehicle Ve is equipped with an engine 1, a first motor 2, and a second motor 3 as driving force sources. Then, the vehicle Ve controls the operating state of each driving force source and the operation of each engaging mechanism 19 in the start clutch 6 and the automatic transmission 7, thereby performing the "EV traveling mode" and the "parallel HV". It is possible to selectively set a plurality of driving modes such as "driving mode" to drive.

The "EV driving mode" is a driving mode in which only the motor is used as the driving force source when the engine 1 is stopped. In the example shown in FIG. 1, the driving force is generated by the driving torque output by the second motor 3. It is a driving mode. In the "EV traveling mode", the vehicle Ve according to the embodiment of the present invention engages the start clutch 6 and shuts off the power transmission in the automatic transmission 7 by the engaging mechanism 19, and the engine 1 (shown in FIG. 1). In the example, the engine 1 and the first motor 2) are separated from the drive system of the vehicle Ve, and the driving force is generated by the drive torque output by the second motor 3 to drive the vehicle.

The "parallel HV driving mode" is a driving mode in which at least the engine 1 is used as a driving force source, and in the example shown in FIG. 1, the driving force is generated by at least the driving torque output by the engine 1. The driving force may be generated by using the driving torque output by both the engine 1 and the second motor 3 together. Alternatively, the driving force may be generated by using the driving torques output by all of the engine 1, the first motor 2, and the second motor 3 in combination. In the "parallel HV traveling mode", the vehicle Ve in the embodiment of the present invention engages the start clutch 6 and sets a predetermined shift stage of the automatic transmission 7 by the engaging mechanism 19 to set the engine 1 (FIG. 1). In the example shown in the above, the engine 1 (or the engine 1 and the second motor 3 or the engine 1, the first motor 2, and the engine 1 and the first motor 2) are connected to the drive system of the vehicle Ve. The driving force is generated by the driving torque output by the second motor 3) to drive the vehicle.

In the example shown in FIG. 1, the vehicle Ve can be driven by selectively setting the "series HV driving mode" in addition to the above-mentioned "EV driving mode" and "parallel HV driving mode". is there. The "series HV driving mode" is a driving mode in which the engine 1 drives the first motor 2 as a generator and generates a driving force with the driving torque output by the second motor 3. That is, the "series HV traveling mode" is a traveling mode in which only the second motor 3 is used as the driving force source without using the engine 1 and the first motor 2 as the driving force source. In this "series HV driving mode", as in the above-mentioned "EV driving mode", the engagement mechanism 19 cuts off the power transmission in the automatic transmission 7, and the engine 1 and the first motor 2 are driven by the vehicle Ve. In a state of being separated from the above, the driving force is generated by the driving torque output by the second motor 3 to drive the vehicle. Therefore, the "series HV driving mode" can be included in the "EV driving mode" as the "EV driving mode" in a broad sense. In the control example according to the embodiment of the present invention described below, the "series HV driving mode" will be described by including the "EV driving mode".

As described above, in a vehicle Ve equipped with a stepped automatic transmission having a plurality of engaging mechanisms 19 such as the automatic transmission 7, a plurality of the vehicles in the automatic transmission 7 are traveling in the "EV traveling mode". If the engaging mechanism 19 of the above is always engaged, a drag loss occurs in the automatic transmission 7, and the energy efficiency of the vehicle Ve is lowered. By releasing the engagement mechanism 19 in the automatic transmission 7 together with the start clutch 6 in the "EV driving mode", the occurrence of the above-mentioned drag loss can be avoided, but in that case, "EV driving" When shifting from the "mode" (or "series HV driving mode") to the "parallel HV driving mode", the driving force responsiveness of the vehicle Ve is lowered. Further, a shock may occur when the engaging mechanism 19 in the automatic transmission 7 is engaged, which may give a sense of discomfort to the driver or the occupant.

For example, the collinear diagram of FIG. 2 shows a state in which the vehicle Ve is traveling in the "EV traveling mode" and the automatic transmission 7 is in the "second speed". In the collinear diagram of FIG. 3, in order to shift from the "EV driving mode" to the "parallel HV driving mode", the automatic transmission 7 is set to the "first speed" standby state (engaged) under the control contents of the [conventional technology]. It shows the state of transition to the ready state).

It should be noted that the collinear diagrams of FIGS. 2 and 3 above, and the collinear diagrams of FIGS. 5 and 6 described later, have 10 forward speeds of the 1st to 10th speeds set as a reference. An example of a 10-speed automatic transmission 7 capable of being used is shown. Although not shown, the 10-speed automatic transmission 7 includes four sets of planetary gear mechanisms of the first planetary gear mechanism, the second planetary gear mechanism, the third planetary gear mechanism, and the fourth planetary gear mechanism, and the first planetary gear mechanism. It is composed of a plurality (six) engaging mechanisms 19 of the clutch C1, the second clutch C2, the third clutch C3, the fourth clutch C4, the first brake B1, and the second brake B2. The first planetary gear mechanism has a first sun gear, a first carrier, and a first ring gear. The second planetary gear mechanism has a second sun gear, a second carrier, and a second ring gear. The third planetary gear mechanism has a third sun gear, a third carrier, and a third ring gear. The fourth planetary gear mechanism has a fourth sun gear, a fourth carrier, and a fourth ring gear.

By releasing the first brake B1 and engaging the second clutch C2 and the second brake B2 together from the state shown in the collinear diagram of FIG. 2 (EV driving mode, second speed), FIG. It becomes the state shown by the collinear diagram of No. 3 (EV running mode, 1st speed engagement ready state). As is clear from the comparison between the collinear diagram of FIG. 2 and the collinear diagram of FIG. 3, in the [conventional technique], the automatic transmission 7 is shifted from the "second speed" to the "first speed" standby state. At that time, the number of rotations of each internal rotating element changes greatly. Therefore, the inertia shuttlek in the automatic transmission 7 fluctuates greatly, which causes a shock and an unintended torque fluctuation (vibration) of the output shaft 7b.

The hybrid vehicle according to the embodiment of the present invention in order to reduce the drag loss in the automatic transmission 7 as described above, and to avoid or suppress the occurrence of unintended shocks and torque fluctuations at the time of transition to the traveling mode. The control device of the above is configured to execute the control shown in the flowchart of FIG. 4 below, for example.

The control shown in the flowchart of FIG. 4 is executed when the vehicle Ve travels in the "EV traveling mode". First, in step S1, it is determined whether or not the vehicle Ve is traveling in the "EV traveling mode".

If the vehicle Ve is traveling in another driving mode (that is, "parallel HV driving mode"), or the vehicle Ve is stopped, and the vehicle Ve is negatively determined in this step S1, the following. The routine shown in the flowchart of FIG. 4 is temporarily terminated without executing the control of. On the other hand, if the vehicle Ve is traveling in the "EV traveling mode" and is positively determined in step S1, the process proceeds to step S2. Even when the vehicle Ve travels in the "series HV travel mode" with the drive torque of only the second motor 3, it is positively determined in step S1 as the "EV travel mode" in a broad sense.

In step S2, for example, the traveling state of the vehicle Ve, which is determined based on the vehicle speed, the required driving force (accelerator pedal opening), and the like, is the first speed traveling region in which the "first speed" should be set by the automatic transmission 7. It is determined whether or not it is in (AT / 1st speed region). In the automatic transmission 7, shift control similar to that of a conventional general stepped automatic transmission is executed. For example, shift control of the automatic transmission 7 is executed based on a shift map that defines a traveling region in which each shift stage should be set according to a vehicle speed and a required driving force (accelerator pedal opening degree).

If the traveling state of the vehicle Ve is not in the first speed traveling region (AT / first speed region) and is negatively determined in step S2, the process proceeds to step S3.

In step S3, it is determined whether or not there is an acceleration request by the driver. For example, it is possible to determine whether or not there is an acceleration request by the driver based on the amount of operation of the accelerator pedal by the driver detected by the accelerator position sensor 8c, the amount of change in the accelerator position (accelerator pedal opening), and the like. When there is an acceleration request from the driver, an engagement instruction (clutch engagement request) is given to the engagement mechanism 19 in the automatic transmission 7.

If it is negatively determined in step S3 because there is no acceleration request (clutch engagement request) by the driver, the routine shown in the flowchart of FIG. 4 is temporarily terminated without executing the subsequent control. .. On the other hand, if the driver makes an acceleration request (clutch engagement request) and affirmatively determines in step S3, the process proceeds to step S4.

In step S4, all the engaging elements of the automatic transmission 7 are engaged. In this case, all the engaging elements are all the engaging mechanisms 19 that are engaged to form a predetermined shift stage (other than the "first speed") set by the automatic transmission 7. Therefore, in this step S4, by engaging all the engaging elements of the automatic transmission 7, a predetermined speed change other than the "first speed" is set in the automatic transmission 7, and the automatic transmission 7 is powered. It becomes a state where it can be transmitted. Further, in this case, although there is an acceleration request by the driver, a large driving force that requires the automatic transmission 7 to be downshifted to the "first speed" is not required. Therefore, it can be assumed that a large shock or torque fluctuation that gives a sense of discomfort to the driver or occupant does not occur when the driving mode is changed. Therefore, in this case, control for suppressing shock and torque fluctuation is not particularly performed, and the transition of the traveling mode is performed with the normal (conventional) control content.

On the other hand, if the traveling state of the vehicle Ve is in the first speed traveling region (AT / first speed region) and is positively determined in step S2 described above, the process proceeds to step S5.

In step S5, it is determined whether or not there is an acceleration request by the driver. For example, it is possible to determine whether or not there is an acceleration request by the driver based on the amount of operation of the accelerator pedal by the driver detected by the accelerator position sensor 8c, the amount of change in the accelerator position (accelerator pedal opening), and the like. When there is an acceleration request from the driver, an engagement instruction (clutch engagement request) is given to the engagement mechanism 19 in the automatic transmission 7.

If it is negatively determined in step S5 because there is no acceleration request (clutch engagement request) by the driver, the routine shown in the flowchart of FIG. 4 is temporarily terminated without executing the subsequent control. .. On the other hand, if the driver makes an acceleration request (clutch engagement request) and affirmatively determines in step S5, the process proceeds to step S6.

In step S6, the automatic transmission 7 is put into a downshift standby state. In the example shown in the collinear diagram of FIG. 2 described above, the automatic transmission 7 is shifted down from the "second speed" to the "first speed", and the automatic transmission 7 is changed from the "second speed" to the "first speed". The engagement preparation for shifting to the "first speed" is carried out (the automatic transmission 7 is put into the standby state of the "first speed"). Specifically, the first clutch C1 and the second clutch C2 are engaged. Further, the first brake B1 is released. In the collinear diagram of FIG. 5, in order to shift from the "EV driving mode" to the "parallel HV driving mode", the state in which the automatic transmission 7 is shifted to the "first speed" standby state (engagement ready state) is shown. It is shown.

By releasing the first brake B1 and engaging the first clutch C1 and the second clutch C2 together from the state shown in the collinear diagram of FIG. 2 (EV driving mode, second speed), FIG. It becomes the state shown by the collinear diagram of No. 5 (EV driving mode, 1st speed). Compared with the example of the [conventional technique] shown in the collinear diagram of FIG. 3, each internal rotation of the automatic transmission 7 when shifting from the "second speed" to the "first speed" state. The rotation speed of the element does not change. Therefore, the inertia shuttlek in the automatic transmission 7 does not fluctuate significantly, and shocks and unintended torque fluctuations (vibrations) of the output shaft 7b due to the fluctuations do not occur. Therefore, it is possible to smoothly shift the driving mode to the "parallel HV driving mode" after that.

Next, in step S7, the engine 1 is cranked so that the engine speed increases to the synchronous speed of the input shaft 7a of the automatic transmission 7. In the example shown in FIG. 1, the engine 1 is cranked (motored) by the torque output by the first motor 2.

Then, in step S8, the engaged starting clutch 6 is temporarily released. As described above, in the "EV traveling mode", the vehicle Ve in the embodiment of the present invention engages the start clutch 6 and releases any of the engaging mechanisms 19 in the automatic transmission 7. The engine 1 is disconnected from the Ve drive system. In this step S7, the starting clutch 6 engaged in order to set the "EV traveling mode" is temporarily controlled to the released state. Specifically, the torque transmission rate (transmission torque capacity) of the starting clutch 6 is reduced, and the starting clutch 6 is temporarily controlled to be in a slip-engaged (half-engaged) state.

Then, in step S9, the final engaging element of the automatic transmission 7 is engaged. Specifically, of the plurality of engaging mechanisms 19 that are engaged to form the shift stage set by the automatic transmission 7, the engaging mechanism 19 (final engaging element) that has not yet been engaged is engaged. Controlled by state. In this case, among the engaging mechanisms 19 that are engaged in order to form the "first speed" in the automatic transmission 7, the engaging mechanism 19 that is not yet engaged is engaged. In the example shown in the collinear diagram of FIG. 2 described above, the automatic transmission 7 is shifted down from the “second speed” to the “first speed”, and here, as shown in the collinear diagram of FIG. The second brake B2 is engaged as the final engaging element of the automatic transmission 7. The collinear diagram of FIG. 6 shows a state in which the automatic transmission 7 has been shifted from the “second speed” to the “first speed” after shifting from the “EV driving mode” to the “parallel HV driving mode”. There is.

Next, in step S10, the starting clutch 6 is engaged to bring the vehicle into a state in which power can be transmitted. That is, the torque transmission rate (transmission torque capacity) of the start clutch 6 temporarily released (slip engagement) in step S8 after the final engagement element of the automatic transmission 7 is engaged is changed. It gradually increases and is brought into an engaged state (a state in which the torque transmission rate is 100%) again.

When the start clutch 6 is engaged again in step S10, the transition of the traveling mode from the "EV traveling mode" to the "parallel HV traveling mode" is completed. That is, in step S11, the transition from the "EV driving mode" to the "parallel HV driving mode" is completed, the engine 1 starts the combustion operation, and the drive torque output by the engine 1 causes the "parallel HV". Driving in "driving mode" becomes possible.

Then, when the transition to the "parallel HV driving mode" is completed in step S11 and the vehicle Ve travels in the "parallel HV driving mode", the routine shown in the flowchart of FIG. 4 is temporarily terminated.

Changes in the behavior of the vehicle Ve (vehicle speed) and the state of the automatic transmission 7 (engagement / disengagement state of each engagement mechanism 19) when the control shown in the flowchart of FIG. 4 is executed as described above. , It is shown in the time chart of FIG.

In the example shown in the time chart of FIG. 7, first, at time t1, the automatic transmission 7 is shifted down from the "second speed" (2nd) to the "first speed" (1st). In the state of "second speed" before time t1, only the first brake B1 is engaged in advance in preparation for engagement of "first speed". In this case, the automatic transmission 7 is in an released state in which the power transmission in the automatic transmission 7 is cut off.

In the "first speed" state from time t1 to time t2, the engaging elements (first clutch C1, second clutch C2, and the first clutch C1, the second clutch C2, and the engaging elements that are engaged to form the "first speed" in the automatic transmission 7 are Of the second brake B2), the first clutch C1 and the second clutch C2 are engaged in advance (prior to the engagement of the second brake B2) in preparation for the transition to the "parallel HV driving mode". ing.

When the engine 1 is started at time t2, that is, when the cranking of the engine 1 by the first motor 2 is started, the input shaft rotation speed of the automatic transmission 7 starts to increase, and the synchronous rotation speed starts at time t3. Matches. That is, the rotation speed of the input shaft of the automatic transmission 7 is synchronized with the target rotation speed of the input shaft 7a in the "first speed".

In the transition transition period of the traveling mode after the time t2, the engaging pressure of the starting clutch 6 is reduced, and the starting clutch 6 is put into the slip engaging state. Then, immediately before the rotation speed synchronization at time t3, the engagement pressure of the start clutch 6 is reduced to the engagement pressure corresponding to the touch point of the start clutch 6. That is, the start clutch 6 is in an released state in which the power transmission is cut off.

While the start clutch 6 is in the released state before and after the time t3, specifically, at the time t3, the input shaft rotation speed of the automatic transmission 7 becomes the target rotation speed of the input shaft 7a at the "first speed". At the same time as synchronization, the final engaging element of the automatic transmission 7, that is, the second brake B2 for forming the "first speed" in the automatic transmission 7 is engaged. Then, after the engagement of the second brake B2 is completed, that is, after the shift of the automatic transmission 7 to the "first speed" is completed, the starting clutch 6 is returned to the engaged state. Specifically, the engagement pressure of the starting clutch 6, which has been lowered to the engagement pressure corresponding to the touch point or less, is increased to the engagement pressure corresponding to the touch point or more.

After that, the starting clutch 6 is put into the slip engaging state toward the fully engaged state of the starting clutch 6, and the engaging pressure of the starting clutch 6 is gradually increased. Then, when the start clutch 6 is in a completely engaged state at time t4, the transition of the traveling mode from the "EV traveling mode" to the "parallel HV traveling mode" is completed.

As described above, the control device for the hybrid vehicle according to the embodiment of the present invention includes the start clutch 6 in which the torque transmission rate or the transmission torque capacity is continuously variable, so that the start clutch 6 can be engaged at the time of starting or at a low vehicle speed. By controlling the slip-engaged state, smooth power transmission becomes possible. Further, by providing the automatic transmission 7 that shifts the engine speed and amplifies the engine torque, for example, the drive torque output by the engine 1 can be effectively utilized when a high load is required. Further, in the hybrid vehicle control device of the present invention, a predetermined shift stage of the automatic transmission 7 is set by controlling the operation of a plurality of engaging mechanisms 19 provided inside the automatic transmission 7. At the same time, the power transmission in the automatic transmission 7 can be cut off. That is, the input shaft 7a and the output shaft 7b of the automatic transmission 7 are released by releasing at least one engagement mechanism 19 of at least two engagement mechanisms 19 that are engaged to set a predetermined shift stage. Power transmission between can be cut off. Therefore, when traveling in the "EV traveling mode", the power transmission in the automatic transmission 7 can be cut off with the starting clutch 6 engaged. Therefore, it is possible to reduce the drag loss in the automatic transmission 7 while traveling in the "EV traveling mode". Then, in the hybrid vehicle control device of the present invention, the so-called replacement of the starting clutch 6 and the engaging mechanism 19 of the automatic transmission 7 is performed when the traveling mode is changed from the "EV traveling mode" to the "parallel HV traveling mode". By performing the control, it is possible to perform power transmission with good responsiveness while suppressing torque fluctuations and clutch engagement shocks due to the inner shuttlek inside the automatic transmission 7. Therefore, according to the hybrid vehicle control device of the present invention, the energy efficiency of the hybrid vehicle Ve is improved by targeting the hybrid vehicle Ve that travels by switching between the "EV driving mode" and the "parallel HV driving mode". It is possible to achieve both good riding comfort and good driving force responsiveness.

1 Engine (driving force source; ENG)
2 1st motor (driving force source; MG1)
3 Second motor (driving force source; MG2)
4 Drive wheels (rear wheels)
5 Drive wheels (front wheels)
6 Start clutch 7 Automatic transmission 7a (automatic transmission) input shaft 7b (automatic transmission) output shaft 8 Detector 8a Vehicle speed sensor (or wheel speed sensor)
8b Engine speed sensor 8c Accelerator position sensor 8d Motor speed sensor (or resolver)
8e Input rotation sensor (for automatic transmission) 8f Output rotation sensor (for automatic transmission) 8g Hydraulic sensor 9 Controller (ECU)
10 Reduction gear 11 Speed change mechanism 12 Rear differential shaft 13 Rear differential gear 14 Rear drive shaft 15 Transfer 16 Front propeller shaft 17 Front differential gear 18 Front drive shaft 19, 19a, 19b (inside the automatic transmission) Engagement mechanism Ve Vehicle (inside the automatic transmission) Hybrid vehicle)

Claims (1)

An engine, at least one motor, a drive wheel, a start clutch capable of continuously changing the torque transmission rate in a power transmission path between the engine and the drive wheel, and the engine and the drive. An automatic transmission that transmits torque between the wheels is provided between the input shaft and the output shaft of the automatic transmission, and the torque transmission rate is continuously changed between the input shaft and the output shaft. An EV traveling mode in which a plurality of engaging mechanisms capable of being operated, the engine, the motor, the starting clutch, and a controller for controlling the engaging mechanism are provided, and only the motor is used as a driving force source. And at least in a hybrid vehicle control device capable of selectively setting a parallel HV driving mode in which the engine is used as a driving force source.
The automatic transmission is configured to set a predetermined shift stage by engaging at least one of the two engaging mechanisms.
The controller
In the EV traveling mode, the starting clutch is engaged and the torque transmission coefficient of at least one of the engaging mechanisms is reduced.
In the parallel HV traveling mode, the starting clutch is engaged, and at least any two of the engaging mechanisms are engaged, and the vehicle is engaged.
When shifting from the EV traveling mode to the parallel HV traveling mode, the torque transmission rate of the engaging mechanism in which the torque transmission rate of the starting clutch is once lowered and the torque transmission rate is lowered in the EV running mode is lowered. A hybrid vehicle control device, characterized in that, after engaging the engaging mechanism, the torque transmission rate of the starting clutch is increased to engage the starting clutch.

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