JP6863312B2 - Hybrid vehicle control device - Google Patents

Description

The present invention relates to a control device for a hybrid vehicle that includes an engine and a motor (or a motor having a power generation function) as a driving force source, and can travel using at least one driving force of the engine and the motor. is there.

An example of this type of hybrid vehicle is described in Patent Document 1. The hybrid vehicle is equipped with an engine and a motor as a driving force source, a stepped automatic transmission is connected to the output side of the engine, and a motor is provided in a power transmission path between the automatic transmission and the drive wheels. Has been done. In addition, when the vehicle speed is high and the accelerator opening is large, the automatic transmission sets a predetermined shift stage, drives the engine, and sets the engine driving mode in which the hybrid vehicle is driven by the output of the engine. It is configured in. On the other hand, when the vehicle speed is low and the accelerator opening is small, the automatic transmission is set to the neutral state, the engine is stopped, and the motor driving mode in which the vehicle is driven by the output of the motor is set. ing. In the motor running mode, one of the plurality of engaging mechanisms of the automatic transmission that is engaged to form a predetermined gear is released to set the pseudo gear. It has become. For example, when the operating point or region of the hybrid vehicle is in the operating region corresponding to the third gear, the engagement mechanism that is commonly engaged in the first to third gears is engaged. Release the other engaging mechanisms that are engaged to form each gear. By doing so, when the accelerator opening is increased to switch from the motor traveling mode to the engine traveling mode and downshift from the third gear to the second gear, another gear forming the second gear is formed. It is said that the engagement mechanism can be engaged quickly.

In the vehicle described in Patent Document 2, a stepped automatic transmission is connected to the output side of the engine via a clutch, and a motor is connected to the output shaft of the automatic transmission. Further, the vehicle is configured to set various traveling states. For example, the clutch is engaged with an EV traveling mode in which the clutch is released, the engine is stopped, and the vehicle is driven only by the output of the motor. It is configured so that an EG driving mode in which the vehicle is driven only by the output of the engine and an HV driving mode in which the vehicle is driven by the output of the engine and the output of the motor by engaging the clutch can be set. Further, when the vehicle speed is equal to or higher than a predetermined vehicle speed, the shift stage of the automatic transmission is changed according to the vehicle speed and the accelerator opening even when the EV driving mode is set. ing.

Japanese Unexamined Patent Publication No. 2010-83351 Japanese Unexamined Patent Publication No. 2013-63715

In the configuration described in Patent Document 1, even in the motor traveling mode, the engaging mechanism that is commonly engaged in the first to third gears is engaged, so that the engaging mechanism is engaged. Rotating members such as gears connected to the output shaft are rotated by the torque transmitted from the drive wheels. That is, since the automatic transmission is carried around, there is a possibility that energy efficiency, fuel consumption, electricity cost, etc. may deteriorate due to power loss due to friction or the like. Further, in the motor running mode, since the mechanical oil pump is stopped together with the engine, the electric oil pump is driven to lubricate the automatic transmission that is being carried around, which worsens the so-called electricity cost. there is a possibility. Note that the configuration described in Patent Document 2 has the same problems as in Patent Document 1 because a predetermined shift stage is set by the automatic transmission even when the EV traveling mode is set.

The present invention has been conceived by paying attention to the above technical problems, and can achieve both reduction of running resistance to suppress deterioration of electricity consumption and fuel consumption and improvement of responsiveness to drive requirements. It is an object of the present invention to provide a control device for a hybrid vehicle capable of providing a control device.

In order to achieve the above object, the present invention comprises an engine, a transmission in which a plurality of shift stages including a neutral state are set according to the engagement and disengagement states of a plurality of friction engagement mechanisms, and the engine. It has a clutch provided between the engine and the transmission to selectively connect the engine and the transmission, and a motor for outputting the motor torque for traveling, and the engine torque output by the engine is calculated as described above. The first traveling mode in which the engine is transmitted to one of the drive wheels via the clutch and the transmission to travel, and the motor torque output by the motor in a state where the clutch is released and the engine is disconnected from the drive wheels. In a hybrid vehicle control device capable of setting a second traveling mode in which When at least one of the required driving force and the vehicle speed of the hybrid vehicle is detected and the required driving force when traveling in the second traveling mode is less than a predetermined reference driving force, and the above-mentioned When the vehicle speed is less than a predetermined reference vehicle speed, all of the plurality of friction engagement mechanisms are released and the clutch is released, and the required driving force when traveling in the second traveling mode is the reference. When the driving force or more, or when the vehicle speed is equal to or higher than the reference vehicle speed, any one of the plurality of friction engagement mechanisms is engaged in a state where a predetermined shift stage is set and the clutch is released. It is characterized by being configured.

According to the present invention, when the vehicle travels in the second traveling mode, the required driving force is less than the preset reference driving force, and the vehicle speed is less than the reference vehicle speed, a plurality of frictions are present. All of the engaging mechanisms are released and the transmission is set to a neutral state where no torque is transmitted. Also, the clutch is released. Therefore, the power loss and the drag loss in the transmission when traveling in the second traveling mode can be reduced as much as possible, and the traveling resistance can be reduced. As a result, it is possible to suppress deterioration of so-called electricity consumption and fuel consumption when the second traveling mode is set. Further, when the required driving force is equal to or higher than the reference driving force, or when the vehicle speed is equal to or higher than the reference vehicle speed, the transition from the second driving mode to the first driving mode is predicted due to the large required driving force and vehicle speed. As a result, the shift stage is set according to the required driving force and the vehicle speed. Therefore, when the required driving force and the vehicle speed are further increased, the transition to the first traveling mode can be promptly performed, and the acceleration responsiveness and the control responsiveness to the driving request can be improved.

It is a figure which shows typically the power train of the hybrid vehicle in embodiment of this invention. It is a chart which collectively shows a plurality of traveling modes which can be set in the hybrid vehicle in embodiment of this invention. It is a figure which shows an example of the map for defining a plurality of traveling modes set in the hybrid vehicle in embodiment of this invention. It is a skeleton figure which shows typically the structure of the transmission in embodiment of this invention. It is a figure which shows the engaging and disengaging state of each clutch and each brake of a transmission in the embodiment of this invention collectively. It is a figure which shows the engagement order of three engagement mechanisms together in the case of setting a predetermined gear stage in the transmission in embodiment of this invention. It is a flowchart which shows an example of the control in embodiment of this invention. The change between the torque of the starting clutch, the torque of each engaging mechanism for setting a predetermined gear stage, and the engine speed when the switching control from the EV driving mode to the parallel HV driving mode shown in FIG. 7 is performed is shown. It is a time chart. Changes in the torque of the starting clutch, the torque of each engagement mechanism that sets a predetermined gear stage, and the engine speed when switching control from the series HV driving mode to the parallel HV driving mode shown in FIG. 7 is performed. It is a time chart which shows. It is a figure which shows the example which changed the value of the required driving force according to the remaining charge of a battery.

FIG. 1 is a diagram schematically showing a power train of a hybrid vehicle according to an embodiment of the present invention. The hybrid vehicle 1 shown in FIG. 1 is a four-wheel drive vehicle based on a front engine / rear wheel drive vehicle (FR vehicle), and includes an engine 2 and two motors 3 and 4 as a driving force source. The engine 2 and the first motor 3 drive the rear wheels (not shown), and the second motor 4 drives the front wheels (not shown). Specifically, the engine 2 is arranged in a so-called vertical position toward the rear of the hybrid vehicle 1 at the front side of the hybrid vehicle 1 and substantially at the center in the vehicle width direction. The engine 2 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 (Exhaust Gas Recirculation) system, and the like are electrically controlled.

The damper mechanism 5, the first motor 3, the start clutch C0, and the transmission 6 are arranged in this order on the output side of the engine 2 and on the same axis as the engine 2. The damper mechanism 5 reduces the fluctuation of the engine torque generated by the engine 2 and transmits it to the downstream side. As an example, between the plate on the driving side and the plate on the driven side and each plate in the torque transmission direction. It is provided with coil springs arranged in, and is configured to reduce fluctuations in engine torque by compressing the coil springs by applying engine torque to those plates and rotating each plate relative to each other.

The first motor 3 has a function as a generator that generates electricity by being driven by receiving the engine torque output by the engine 2 (power generation function), and is driven by being supplied with electric power to output the motor torque. It has a function as an electric motor (electric function). That is, the first motor 3 is a motor generator having a power generation function, and is composed of, for example, a permanent magnet type synchronous motor, an induction motor, or the like. Further, a battery (not shown) is connected to the first motor 3 via an inverter. Therefore, the first motor 3 can be driven as a generator, and the electric power generated at that time can be stored in the battery or supplied to the second motor 4. Further, the first motor 3 can be driven by the electric power stored in the battery to output the motor torque.

The starting clutch C0 corresponds to the clutch in the embodiment of the present invention, and in the example shown here, power is selectively transmitted and cut off between the engine 2 and the first motor 3 and the rear wheels. It is a hydraulic friction engagement device configured in. The start clutch C0 has a friction plate on the drive side connected to the rotor shaft of the first motor 3 and a friction plate on the driven side connected to the input shaft 7 of the transmission 6. Then, the oil pressure supplied from the oil pump (not shown) is increased, and the friction plates come into contact with each other to be in an engaged state, so that the engine 2 and the first motor 3 are connected to the drive system of the hybrid vehicle 1. Further, the oil pressure is lowered and the friction plates are separated from each other to be in an released state, and the engine 2 and the first motor 3 are separated from the drive system of the hybrid vehicle 1. The start clutch C0 has a plurality of friction plates on the drive side and a plurality of friction plates on the driven side, and is composed of a multi-plate clutch in which the friction plates on each drive side and the friction plates on each driven side are alternately arranged. You can also do it.

The transmission 6 is basically a mechanism capable of appropriately changing the ratio of the input rotation speed to the output rotation speed, and is composed of a forward 10-speed multi-stage automatic transmission described later. Further, the transmission 6 includes at least one transmission clutch TC capable of transmitting torque by engaging and blocking torque transmission by disengaging to set a neutral state. In the embodiment of the present invention, the transmission 6 is not limited to a multi-speed transmission having 10 forward speeds, and a multi-speed transmission having a speed lower than or higher than that can be used.

The rear propeller shaft 9 is connected to the output shaft 8 of the transmission 6. The rear propeller shaft 9 extends rearward from the transmission 6 in the front-rear direction of the hybrid vehicle 1, and the rear differential gear 10 is connected to the rear propeller shaft 9. The left and right rear wheels (drive wheels) are connected to the rear differential gear 10 via a drive shaft (not shown).

The above-mentioned second motor 4 corresponds to the motor in the embodiment of the present invention, and is connected to the left and right front wheels so as to be able to transmit power. In the example shown here, the second motor 4 has a function as a prime mover that is driven by being supplied with electric power to output motor torque, and a power generator that generates electricity by being driven by receiving torque from the outside. It has a function as a machine. That is, the second motor 4 is a motor generator having a power generation function like the first motor 3, 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 second motor 4 via an inverter, and the second motor 4 can be driven by electricity from the battery to output motor torque. Further, since the second motor 4 is connected to the front wheels so as to be able to transmit power, the second motor 4 can be driven as a generator by the torque transmitted from the front wheels, and the electric power generated by the second motor 4 can be stored in the battery. it can. Further, the first motor 3 and the second motor 4 described above are connected to each other via an inverter so that electric power can be exchanged with each other. For example, the electricity generated by the first motor 3 is transferred to the second motor 4. It is also possible to directly supply to the motor 4 and output the motor torque with the second motor 4.

The front propeller shaft 11 is connected to the rotor shaft of the second motor 4. The front propeller shaft 11 is arranged parallel to the rear propeller shaft 9 and extends forward from the second motor 4 in the front-rear direction of the hybrid vehicle 1. The front differential gear 12 is connected to the front propeller shaft 11. The left and right front wheels (drive wheels) are connected to the front propeller shaft 11 via a drive shaft (not shown). The front propeller shaft 11 is arranged so as to be biased to either the right side or the left side with respect to the central portion in the vehicle width direction with the engine 2 and the transmission 6 sandwiched in the vehicle width direction. Further, the second motor 4 is housed inside the motor case 13.

An electronic control device (hereinafter referred to as an ECU) 15 corresponding to the controller according to the embodiment of the present invention that controls the operating state of the engine 2 shown in FIG. 1, the gear ratio of the transmission 6, and the operation of the transmission clutch TC is provided. ing. The ECU 15 is mainly composed of, for example, a microcomputer, performs a calculation using input data and data stored in advance, outputs the result of the calculation as a control command signal, and outputs the result of the calculation to the engine 2 and the engine 2. It is configured to control the transmission 6 and the transmission clutch TC, respectively. The data input to the ECU 15 is data from various sensors, switches, or other systems. Examples of these sensors, switches, or systems include a vehicle speed sensor 16 and an accelerator opening sensor 17.

In the hybrid vehicle 1 having the configuration shown in FIG. 1, it is possible to set a plurality of traveling modes and travel. FIG. 2 is a chart showing a plurality of traveling modes that can be set in the hybrid vehicle 1 according to the embodiment of the present invention. As shown in FIG. 2, the hybrid vehicle 1 is driven by the motor torque output by the second motor 4 with the start clutch C0 and the transmission clutch TC released and the engine 2 and the first motor 3 stopped. The EV driving mode can be set. Further, the engine 2 is operated with the start clutch C0 and the transmission clutch TC released, the first motor 3 is driven by the engine 2 to generate power, and the second motor 4 is driven by the generated power. The series HV driving mode in which the hybrid vehicle 1 is driven can be set by the motor torque of the two motors 4. Further, it is possible to set a parallel HV traveling mode in which the engine 2 is operated with the starting clutch C0 and the transmission clutch TC engaged, and the hybrid vehicle 1 is driven by the engine torque and the motor torque of the second motor 4. .. In this parallel HV traveling mode, the hybrid vehicle 1 can be driven by the motor torque output by the first motor 3 in addition to the engine torque and the motor torque of the second motor 4. Further, in the parallel HV driving mode, the reaction force torque with respect to the target engine torque is controlled to be output to the first motor 3. In this case, regenerative control that causes the first motor 3 to function as a generator can be executed. In each of the above-described traveling modes, regenerative control for causing the second motor 4 to function as a generator can be performed during deceleration or the like, and the electric power generated by the regenerative control can be stored in the battery. The parallel HV traveling mode described above corresponds to the first traveling mode in the embodiment of the present invention, and the EV traveling mode and the series HV traveling mode described above correspond to the second traveling mode in the embodiment of the present invention.

FIG. 3 is a diagram showing an example of a map for determining a plurality of traveling modes set in the hybrid vehicle 1 according to the embodiment of the present invention. The horizontal axis in FIG. 3 indicates the vehicle speed V, and the vertical axis indicates the driving force. In the example shown in FIG. 3, the EV traveling mode is set when the vehicle is traveling forward and the vehicle speed V is equal to or less than the predetermined EV traveling maximum vehicle speed Va and the driving force is relatively small. The area in which the EV driving mode is set is shown with hatching in FIG. The maximum driving force in the EV traveling mode is predetermined based on the characteristics of the second motor 4, the performance of the battery, and the like. As shown in FIG. 3, the maximum driving force in the EV traveling mode is set to decrease as the vehicle speed V increases. The maximum EV traveling vehicle speed Va described above corresponds to the reference vehicle speed in the embodiment of the present invention.

When the vehicle speed V is equal to or less than the maximum EV traveling speed Va and the driving force is equal to or greater than the maximum driving force in the EV traveling mode, the series HV traveling mode is set. The maximum driving force in the series HV driving mode is predetermined based on the characteristics of the second motor 4, the performance of the battery, the characteristics of the first motor 3 that functions as a generator, and the like. As shown in FIG. 3, the maximum driving force in the series HV driving mode is set to decrease as the vehicle speed V increases. When the vehicle speed V is equal to or greater than the maximum EV traveling vehicle speed Va or the driving force is equal to or greater than the maximum driving force in the series HV traveling mode, the parallel HV traveling mode is set. Since each of the above-mentioned HV driving modes can output the driving force from the low vehicle speed range to the high vehicle speed range, the EV driving mode is used when the remaining charge SOC of the battery (not shown) is close to the lower limit value. The HV driving mode may be set even in the area where is to be set.

Further, the solid line shown in FIG. 3 indicates a running resistance corresponding to a required driving force in the case of steady traveling on a flat road, that is, when traveling on a flat road at a predetermined constant vehicle speed. Further, the broken line shown in FIG. 3 indicates a driving force (hereinafter, referred to as a required driving force) Fa required for driving the hybrid vehicle 1 at a predetermined acceleration G against the traveling resistance as described above. Is shown. As the required driving force Fa, it is preferable to set the driving force when traveling on an uphill road having a gradient of about 5%. Since the above-mentioned traveling resistance increases as the vehicle speed V increases, the required driving force Fa is set so as to increase as the vehicle speed V increases. That is, the required driving force Fa shown in FIG. 3 is a driving force when the hybrid vehicle 1 is driven in a state where a relatively large running resistance or a high load is acting on the hybrid vehicle 1, and is a driving force when the hybrid vehicle 1 is driven, and is a transmission clutch in the transmission 6. It is used as a threshold for driving force to determine whether to engage the TC and set the torque transmission state in the transmission 6 or to release the transmission clutch TC and set the neutral state in which the transmission 6 does not transmit torque. Can be done. The required driving force Fa can be set in advance based on the results of a running experiment or a simulation, and the required driving force Fa corresponds to the reference driving force in the embodiment of the present invention.

Here, a specific configuration of the transmission 6 described above will be described. FIG. 4 is a skeleton diagram showing a 10-speed forward transmission that can be adopted as an embodiment of the present invention. The transmission 6 includes a labinho type first planetary gear mechanism 18, a single pinion type second planetary gear mechanism 19, and a single pinion type third planetary gear mechanism 20 as main gear mechanisms. The first planetary gear mechanism 18 meshes with two sun gears S181 and S182, a ring gear R18, and a first pinion gear P181 and a second sun gear S182 and a first pinion gear P181 meshing with the sun gear S181 and the ring gear R18. A carrier C18 holding the two pinion gears P182 is provided as a rotating element that performs a differential action with each other. A first brake B1 for selectively fixing the first sun gear S181 to a fixed portion such as a transmission case 14 is provided.

The second planetary gear mechanism 19 and the third planetary gear mechanism 20 are arranged on the same axis as the first planetary gear mechanism 18 described above, and the second planetary gear mechanism 19 includes a sun gear S19, a ring gear R19, and the like. A carrier C19 holding a pinion gear P19 meshing with the sun gear S19 and the ring gear R19 is provided as a rotating element that performs a differential action with each other. Similarly, the third planetary gear mechanism 20 is a rotating element that differentially acts on the sun gear S20, the ring gear R20, and the carrier C20 holding the pinion gear P20 that meshes with the sun gear S20 and the ring gear R20. Prepared as.

The sun gear S19 of the second planetary gear mechanism 19 and the sun gear S20 of the third planetary gear mechanism 20 are integrated with each other, and these sun gears S19 and S20 and the ring gear R18 in the first planetary gear mechanism 18 described above are selectively selected. A first clutch C1 connected to is provided. Further, a second clutch C2 for selectively connecting the sun gears S19 and S20 integrated with each other and the second sun gear S182 in the first planetary gear mechanism 18 is provided. Further, a third clutch C3 is provided which selectively connects the ring gear R19 of the second planetary gear mechanism 19 and the ring gear R18 of the first planetary gear mechanism 18. A second brake B2 that selectively stops the rotation of the ring gear R19 of the second planetary gear mechanism 19 is provided.

The carrier C18 in the first planetary gear mechanism 18 and the carrier C20 in the third planetary gear mechanism 20 are connected to the input shaft 7, and these carriers C18 and C20 are input elements of the transmission 6. Further, the carrier C19 of the second planetary gear mechanism 19 is connected to the output shaft 8 of the transmission 6, and the carrier C19 of the second planetary gear mechanism 19 is an output element. A fourth clutch C4 that selectively connects the carrier C19 of the second planetary gear mechanism 19 and the ring gear R20 of the third planetary gear mechanism 20, which is the output element, is provided. When the fourth clutch C4 is engaged, the second planetary gear mechanism 19 and the third planetary gear mechanism 20 are connected to each other by two rotating elements without causing a differential action. It rotates as one.

Each of the first clutch C1, the second clutch C2, the third clutch C3, the fourth clutch C4, the first brake B1 and the second brake B2 described above is, for example, a friction type engaging mechanism that is engaged and released by hydraulic pressure. It is configured so that their torque capacities can be continuously changed. The clutches C1, C2, C3, C4 and the brakes B1 and B2 correspond to the friction engagement mechanism in the embodiment of the present invention and the transmission clutch TC described above.

In the above-mentioned transmission 6 shown in FIG. 4, 10 forward speeds (1st to 10th) and reverse speed (Rev) can be set. The engaging mechanisms for engaging and disengaging in these gears are summarized in FIG. In FIG. 5, the “◯” mark indicates the engaged state, and the blank indicates the released state. The control for engaging and disengaging these engaging mechanisms can be performed by a conventionally known hydraulic control device (not shown), and the hydraulic control device can now be electrically controlled. ing.

In the example shown in FIG. 5, the first forward speed stage is set by engaging the first clutch C1, the second clutch C2, and the second brake B2. The second forward speed stage is set by engaging the first clutch C1, the first brake B1 and the second brake B2. The third forward speed stage is set by engaging the second clutch C2, the first brake B1 and the second brake B2. The fourth forward speed stage is set by engaging the fourth clutch C4, the first brake B1 and the second brake B2. The fifth forward speed stage is set by engaging the second clutch C2, the fourth clutch C4, and the first brake B1. The sixth forward speed stage is set by engaging the first clutch C1, the fourth clutch C4, and the first brake B1. The 7th forward speed stage is set by engaging the 1st clutch C1, the 3rd clutch C3, and the 4th clutch C4. The 8th forward speed stage is set by engaging the 3rd clutch C3, the 4th clutch C4, and the 1st brake B1. The ninth forward speed stage is set by engaging the first clutch C1, the third clutch C3, and the first brake B1. The 10th forward speed stage is set by engaging the second clutch C2, the third clutch C3, and the first brake B1. The reverse stage Rev is set by engaging the second clutch C2, the third clutch C3, and the second brake B2.

The operating state of the transmission 6, that is, the setting state of the gear stage described above can be electrically and appropriately set. For the setting of the gear stage, a gear stage suitable for the running state is calculated based on the drive data such as the vehicle speed V and the accelerator opening ACC using the shift map prepared in advance, and each gear stage is set so as to set the gear stage. The engaging mechanisms such as the clutches C1, C2, C3 and C4 and the brakes B1 and B2 are engaged and disengaged. Further, in the embodiment of the present invention, when engaging the three engaging mechanisms forming the gear stage, the three engaging mechanisms are used in order to suppress over-rotation of each rotating element such as a gear in the transmission 6. The mechanisms are engaged in a predetermined order. The engagement order can be preset by simulation or the like.

FIG. 6 shows the engagement order of the three engagement mechanisms of the clutches C1, C2, C3, C4 and the brakes B1 and B2 when the predetermined gear stage is set by the transmission according to the embodiment of the present invention. It is a chart which shows collectively. When setting the first forward speed stage, the control for engaging the second brake B2 is started first, then the control for engaging the second clutch C2 is started, and then the first clutch C1 is engaged. Control is started. When setting the forward second speed stage, the control for engaging the first brake B1 is started first, then the control for engaging the second brake B2 is started, and then the first clutch C1 is engaged. Control is started. When setting the forward third speed, the control for engaging the first brake B1 is started first, then the control for engaging the second brake B2 is started, and then the second clutch C2 is engaged. Control is started. When setting the forward fourth speed stage, the control for engaging the first brake B1 is started first, then the control for engaging the second brake B2 is started, and then the fourth clutch C4 is engaged. Control is started. When setting the forward fifth speed, the control for engaging the first brake B1 is started first, then the control for engaging the fourth clutch C4 is started, and then the second clutch C2 is engaged. Control is started. When setting the forward sixth speed, the control for engaging the first brake B1 is started first, then the control for engaging the fourth clutch C4 is started, and then the first clutch C1 is engaged. Control is started. When setting the 7th forward speed stage, the control for engaging the third clutch C3 is started first, then the control for engaging the first clutch C1 is started, and then the control for engaging the fourth clutch C4 is started. Control is started. When setting the forward eighth speed stage, the control for engaging the third clutch C3 is started first, then the control for engaging the fourth clutch C4 is started, and then the first brake B1 is engaged. Control is started. When setting the forward 9th speed, the control for engaging the third clutch C3 is started first, then the control for engaging the first clutch C1 is started, and then the first brake B1 is engaged. Control is started. When setting the 10th forward speed stage, the control for engaging the third clutch C3 is started first, then the control for engaging the second clutch C2 is started, and then the first brake B1 is engaged. Control is started.

In the hybrid vehicle 1 according to the embodiment of the present invention, as described above, when traveling in the EV traveling mode, the stopped engine 2, the first motor 3, the transmission 6, and the like become traveling resistance. Therefore, these are separated from the drive wheels. Further, when traveling in the series HV traveling mode, the transmission 6 becomes a traveling resistance, which is separated from the drive wheels. In such disconnection control, the start clutch C0 is released, and the transmission 6 is set to the neutral state in which torque is not transmitted. Further, when the required driving force increases while traveling in the EV traveling mode or the series HV traveling mode, the switching to the parallel HV traveling mode is executed. In the hybrid vehicle 1 according to the embodiment of the present invention, in order to achieve both reduction of the above-mentioned traveling resistance to suppress deterioration of electricity consumption and fuel consumption and improvement of responsiveness of switching to the parallel HV traveling mode. Then, the control described below is executed.

FIG. 7 is a flowchart for explaining an example of the control, which is repeatedly executed at predetermined short time intervals. The control shown in FIG. 7 is executed by the above-mentioned ECU 15.

In the flowchart shown in FIG. 7, first, it is determined whether or not the required driving force at the present time is in the region where the parallel HV traveling mode is set (step S101). The required driving force is obtained based on the vehicle speed V and the accelerator opening ACC by the driver. As described above, the driving force in the parallel HV driving mode is larger than the maximum driving force in the series HV driving mode. Therefore, in step S101, whether or not the required driving force is equal to or greater than the maximum driving force in the series HV driving mode. Is judged. As shown in FIG. 3, the maximum driving force in the series HV driving mode is set so that the higher the vehicle speed V, the smaller the value. Therefore, at the current vehicle speed V, the above-mentioned determination is made, and if the required driving force is equal to or greater than the maximum driving force in the series HV driving mode, a positive determination is made in step S101, and the process proceeds to step S102.

In step S102, the parallel HV traveling mode is set. That is, when the engine 2 is started, the start clutch C0 is engaged, and in the transmission 6, a gear stage suitable for the traveling state is selected, and three engaging mechanisms for setting the gear stage are in the order described above. Engage. Then return.

If a negative determination is made in step S101, the process proceeds to step S103. In step S103, it is determined whether or not the required driving force at the present time is in the region for setting the series HV driving mode. That is, it is determined whether or not the required driving force is equal to or greater than the maximum driving force in the EV driving mode and smaller than the maximum driving force in the series HV driving mode. As shown in FIG. 3, the maximum driving force in the EV traveling mode is set so that the higher the vehicle speed V, the smaller the value. Therefore, at the current vehicle speed V, the above-mentioned determination is made, and if the required driving force is equal to or greater than the maximum driving force in the EV driving mode and is in the series HV driving mode, a positive determination is made in step S103. The process proceeds to step S104.

In step S104, the series HV driving mode is set. That is, the engine 2 is started and the start clutch C0 is set to the released state. Then, the first motor 3 is driven by the engine 2 as a generator, the second motor 4 is driven by the electricity generated by the first motor 3, and the vehicle travels by the power generated by the second motor 4. Then, the process proceeds to step S106.

If a negative determination is made in step S103, the process proceeds to step S105. In step S105, the EV traveling mode is set. That is, both the engine 2 and the first motor 3 are set to the stopped state, and the start clutch C0 is set to the released state. Then, the second motor 4 is driven by the electricity supplied from the battery, and travels by the power generated by the second motor 4. Then, the process proceeds to step S106.

In step S106, it is determined whether or not the required driving force at the present time is equal to or greater than the required driving force Fa. When the required driving force at the present time is equal to or greater than the required driving force Fa, a large driving force is required for the hybrid vehicle 1, and in the future, when accelerating and traveling, the parallel HV driving mode is adopted. It can be determined that switching is necessary. Therefore, if a positive determination is made in step S106, the process proceeds to step S107.

In step S107, in preparation for the transition to the parallel HV traveling mode, a gear stage suitable for the current traveling state is selected, and three engaging mechanisms for setting the gear stage are engaged. Then return.

If a negative determination is made in step S106, the process proceeds to step S108. In step S108, it is determined whether or not the current vehicle speed V is equal to or higher than the maximum EV traveling vehicle speed Va. For example, when the vehicle is accelerated by coasting on a downhill without depressing the accelerator pedal or the brake pedal and the vehicle speed V is equal to or higher than the maximum EV traveling speed Va, it is positively determined in step S108 and described above. The process proceeds to step S107. On the other hand, if a negative determination is made in step S108, the process proceeds to step S109. In step S109, the transmission 6 is set or maintained in a neutral state in which all engaging mechanisms are released in order to minimize unnecessary rotation of the transmission 6. Then return.

Changes in the torque of the starting clutch C0, the torque of each engaging mechanism that sets a predetermined gear stage, and the engine speed when switching control from the EV driving mode to the parallel HV driving mode shown in FIG. 7 is performed. FIG. 8 is a time chart. When the hybrid vehicle 1 is traveling in the EV driving mode, the accelerator opening ACC is increased in that state, and the required driving force based on the vehicle speed V and the accelerator opening ACC becomes the required driving force Fa or more at t1 point, the present Control to set the gear stage suitable for the running condition of the vehicle is started. Specifically, the gear stage is calculated according to the current vehicle speed V and the required driving force using the shift map, and the control for engaging the three engaging mechanisms for setting the gear stage in the above-mentioned order is started. Will be done. As shown in FIG. 8, when the forward eighth speed stage is set, the control for engaging the third clutch C3 is started first, then the control for engaging the fourth clutch C4 is started, and then the control for engaging the fourth clutch C4 is started. The control for engaging the first brake B1 is started. Therefore, the third clutch C3, the fourth clutch C4, and the first brake B1 are engaged in this order.

When the accelerator opening ACC further increases at t2 and the required driving force becomes larger than the switching driving force from the EV driving mode to the parallel HV driving mode at t3, the engine 2 is started. In the example shown here, in order to switch from the EV driving mode to the parallel HV driving mode, the switching driving force described above may be the maximum driving force in the series HV driving mode, or may be preset by simulation. Good. Further, in the hybrid vehicle 1 having the above configuration, the engine 2 is started by cranking the engine 2 by the first motor 3 or by a starter motor (not shown), and the engine speed gradually increases. When the engine speed and the input shaft speed of the transmission 6 at the eighth forward speed are synchronized at t4, the control for engaging the start clutch C0 is started. After that, when the start clutch C0 is completely engaged at t5, the switching from the EV traveling mode to the parallel HV traveling mode is completed. On the other hand, conventionally, at t3 when the required driving force becomes larger than the parallel HV switching driving force, control for forming a gear stage suitable for the current traveling state is started. In the example shown here, the third clutch C3, the fourth clutch C4, and the first brake B1 forming the eighth forward speed stage are engaged in the order described above. Then, the engagement of the start clutch C0 starts from the time t6 when the engagement of the first brake B1 ends, and the engagement of the start clutch C0 ends at the time t7. As described above, in the embodiment of the present invention, the time required for engaging each engaging mechanism as a whole of the device can be shortened as compared with the conventional case. That is, the responsiveness to the drive request can be improved unprecedentedly.

FIG. 9 shows the torque of the starting clutch C0 when the switching control from the series HV driving mode shown in FIG. 7 to the parallel HV driving mode is performed, the torque of each engaging mechanism for setting a predetermined gear stage, and the engine rotation. It is a time chart showing a change from a number. As shown in FIG. 9, the hybrid vehicle 1 is traveling in the series HV driving mode, and the accelerator opening ACC is increased in that state, and a required driving force based on the vehicle speed V and the accelerator opening ACC is required at t8. When the driving force becomes Fa or more, the control for setting the gear stage suitable for the current running state is started. Specifically, the gear stage is calculated according to the current vehicle speed V and the required driving force using the shift map, and the control for engaging the engaging mechanism for setting the gear stage in the above-mentioned order is started. .. As shown in FIG. 9, when the forward eighth speed stage is set, the control for engaging the third clutch C3 is started first, then the control for engaging the fourth clutch C4 is started, and then the control for engaging the fourth clutch C4 is started. The control for engaging the first brake B1 is started. Therefore, the third clutch C3, the fourth clutch C4, and the first brake B1 are engaged in this order.

When the accelerator opening ACC and the required driving force based on the accelerator opening ACC are further increased at t9, the amount of power generated by the first motor is increased, so that the engine speed is gradually increased. The driving mode is switched to the parallel HV mode at t10 when the required driving force becomes larger than the switching driving force from the series HV driving mode to the parallel HV driving mode (hereinafter referred to as the parallel HV switching driving force). Then, when the engine speed and the input shaft speed of the transmission 6 at the eighth forward speed are synchronized at t10, the control for engaging the start clutch C0 is started. After that, when the start clutch C0 is completely engaged at t11, the switching from the series HV driving mode to the parallel HV driving mode is completed. On the other hand, conventionally, a gear stage suitable for the current running state is formed at a time point between t9 and t10, and at t12 when the required driving force becomes larger than the parallel HV switching driving force. Control is started. In the example shown here, the third clutch C3, the fourth clutch C4, and the first brake B1 forming the eighth forward speed stage are engaged in the order described above. Then, the engagement of the start clutch C0 is started from the time of t13 when the engagement of the first brake B1 is completed, and the engagement of the start clutch C0 is finished at the time of t14. As described above, also in the example shown in FIG. 9, the time required for engaging each engaging mechanism as a whole of the device can be shortened as compared with the conventional case. That is, the responsiveness to the drive request can be improved unprecedentedly.

Therefore, in the above control, the vehicle travels in the EV driving mode or the series HV driving mode and when the required driving force exceeds the required driving force Fa, and in the EV driving mode or the series HV driving mode. If the vehicle speed exceeds the maximum EV traveling vehicle speed Va, it is determined that the vehicle is expected to travel under a high load in the future. Then, the setting of the gear stage suitable for the current running state is started. Therefore, after that, when the required driving force is further increased to switch to the parallel HV driving mode, the start clutch C0 is promptly engaged when the engine speed reaches the synchronous speed corresponding to the gear stage. Can be done. As a result, the switching time of the traveling mode is shortened, and the control responsiveness or the acceleration responsiveness is improved. When the required driving force is smaller than the required driving force Fa, the clutches C1, C2, C3, C4 and the brakes B1 and B2 are set to the fully released state in the transmission 6, and the state is maintained. Will be done. Therefore, power loss and drag loss due to friction and the like can be reduced as much as possible, and deterioration of electricity consumption and fuel consumption can be suppressed. Further, since the electric oil pump (not shown) that lubricates the transmission 6 can be stopped, it is possible to suppress the deterioration of the electricity cost.

Although a plurality of embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned examples, and may be appropriately modified as long as the object of the present invention is achieved. FIG. 10 shows an example in which the value of the required driving force Fa is changed to a large or small value according to the remaining charge SOC of the battery. As shown in FIG. 10, when the remaining charge SOC is low, the required driving force Fa is set to a relatively small value, and when the remaining charge SOC is high, the required driving force Fa is set to a relatively large value. Set. That is, when the remaining charge SOC is low, it is easy to shift from the EV driving mode or the series HV driving mode to the parallel HV driving mode. Even with such a configuration, it is possible to obtain the same action / effect as the configuration shown in FIG. 1 described above. Further, when the required driving force is smaller than the required driving force Fa and the transmission 6 is set to the neutral state, at least one of the three engaging mechanisms for setting a predetermined gear stage is released. You may set the neutral state. In short, it suffices to be configured so that the running resistance can be reduced by reducing the power loss and the drag loss as much as possible.

1 ... Hybrid vehicle, 2 ... Engine, 3 ... 1st motor, 4 ... 2nd motor, 6 ... Transmission, 15 ... Electronic controller (controller), C0, C1, C2, C3, C4 ... Clutch, B1, B2 …brake.

Claims (1)

The engine, a transmission in which a plurality of shift stages including a neutral state are set according to the engagement and disengagement states of the plurality of friction engagement mechanisms, and the engine provided between the engine and the transmission. It has a clutch that selectively connects the engine and the transmission, and a motor that outputs motor torque for traveling, and the engine torque output by the engine is transmitted to any of the drive wheels via the clutch and the transmission. The first traveling mode in which the engine is disengaged from the driving wheels, and the motor torque output by the motor is transmitted to one of the driving wheels to travel in a state where the clutch is released and the engine is disconnected from the driving wheels. In a hybrid vehicle control device that can set two driving modes
The plurality of friction engaging mechanisms and a controller for controlling the clutch are provided.
The controller
Detecting at least one of the required driving force and the vehicle speed of the hybrid vehicle,
When the required driving force during traveling in the second traveling mode is less than a predetermined reference driving force and the vehicle speed is less than a predetermined reference vehicle speed, the plurality of friction engagements are performed. Release all of the mechanism and release the clutch,
When the required driving force during traveling in the second traveling mode is equal to or higher than the reference driving force, or when the vehicle speed is equal to or higher than the reference vehicle speed, any one of the plurality of friction engagement mechanisms is specified. A control device for a hybrid vehicle, which is configured to engage with a state in which a gear is set and to release the clutch.

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