JP6222158B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention belongs to a technical field related to a control device for a hybrid vehicle.

  Conventionally, an engine, a motor provided on the downstream side of the power transmission path of the engine, a clutch for connecting / disconnecting power transmission between the engine and the motor, and a downstream side of the power transmission path of the motor are provided. A parallel-type hybrid vehicle including an automatic transmission is known (for example, see Patent Document 1). In Patent Document 1, when the vehicle is decelerated at the time of vehicle deceleration and regenerative, first shift control means for executing shift control based on at least one of transmission efficiency of the transmission and power generation efficiency of the motor, and at the time of vehicle deceleration When the clutch is engaged and regenerated, the second shift control means for executing a shift control for reducing the transmission gear ratio of the transmission compared to the execution of the shift control by the first shift control means; As a result, when the clutch is disengaged and regenerated during vehicle deceleration, the transmission efficiency of the transmission and the power generation efficiency of the motor can be made appropriate to increase the regeneration efficiency during vehicle deceleration, and the clutch is engaged and the motor When the engine is in a connected state, the engine torque loss is reduced so that the regeneration efficiency during deceleration can be increased.

JP2012-224321A

  By the way, the above-mentioned clutch between the engine and the motor is usually a wet multi-plate clutch having a plurality of friction plates immersed in oil. A loss (so-called clutch drag loss) occurs in the clutch due to the viscous resistance of oil between the plate and the friction plate that is connected to the engine side and does not rotate. The loss in the clutch increases as the rotational speed difference between the motor-side friction plate and the engine-side friction plate increases.

  Here, in Patent Document 1, gear shifting control is executed based on at least one of transmission transmission efficiency and motor power generation efficiency during vehicle deceleration when the clutch is in a released state. Since loss is not taken into consideration, it is insufficient from the viewpoint of further increasing the regeneration efficiency of the motor.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a motor that is operated when the engine is stopped and the clutch is disengaged and the vehicle is driven by the motor. The purpose is to increase the regeneration efficiency of the motor by reducing the loss in the clutch (the drag loss) as much as possible when the regeneration state is reached.

  In order to achieve the above object, in the present invention, an engine, a motor provided on the downstream side of a power transmission path of the engine, a clutch for connecting / disconnecting power transmission between the engine and the motor, Targeting a control apparatus for a hybrid vehicle including an automatic transmission provided downstream of a power transmission path of a motor, an engine control unit that controls the operation of the engine, and a motor control unit that controls the operation of the motor A clutch control unit that controls the operation of the clutch, a gear ratio control unit that controls a gear ratio of the automatic transmission so as to become a basic gear ratio set in advance according to a traveling state of the vehicle, The motor controlled by the motor control unit when the engine is stopped by the engine control unit and the clutch is released by the clutch control unit. When the motor is in a regenerative state under the control of the motor control unit in response to a deceleration request from the vehicle occupant when the vehicle is running, the speed ratio of the automatic transmission is set to the speed ratio. And a gear ratio changing unit that executes a gear ratio changing process for changing the basic gear ratio by the control unit to a gear ratio on the higher speed side than the basic gear ratio.

  With the above configuration, when the motor is in the regenerative state, the gear ratio changing unit changes the gear ratio of the automatic transmission from the basic gear ratio to a gear ratio on the higher speed side than the basic gear ratio. The rotational speed of the input shaft of the automatic transmission, that is, the rotational speed of the motor is lower than that in the case where the gear ratio changing process is not executed. As a result, the rotational speed difference between the motor-side friction plate and the engine-side friction plate in the clutch is reduced, and the loss (drag loss) in the clutch is reduced. The running resistance of the vehicle is reduced by the amount of loss in the clutch, and as a result, the motor regeneration efficiency is increased.

The hybrid vehicle control device further includes an inter-vehicle distance sensor that detects an inter-vehicle distance between the vehicle and a preceding vehicle that travels in front of the vehicle, wherein the speed ratio changing unit is When the vehicle is running by the motor controlled by the motor control unit when the vehicle is running by the motor controlled by the motor control unit. Even if the motor is in a regenerative state under the control of the motor control unit, the gear ratio changing process is not executed when the inter-vehicle distance detected by the inter-vehicle distance sensor is equal to or less than a predetermined distance. It is preferable.

That is, when the speed change ratio process is executed when the motor is in the regenerative state and the speed change ratio is set to the high speed side, if there is an acceleration request within a predetermined time, the high speed side It becomes necessary to switch (shift down) from a gear ratio to a gear ratio on the low speed side, and a large downshift occurs in a short time after the upshift, resulting in a decrease in drivability. Therefore, in the situation where the inter-vehicle distance detected by the inter-vehicle distance sensor is equal to or less than the predetermined distance, the vehicle will follow the preceding vehicle and there is a high possibility that acceleration and deceleration are repeated frequently. The driver at the time of an acceleration request after a deceleration request is determined by determining that there is a high possibility that an acceleration request will occur within a predetermined time from the start and the speed ratio changing process is not executed even when the motor is in a regenerative state. Can be improved.

In the hybrid vehicle control device, the speed ratio changing unit is controlled by the motor control unit when the engine is stopped by the engine control unit and the clutch is released by the clutch control unit. When the vehicle is traveling by the motor, even if the motor is in a regenerative state by the control of the motor control unit due to a deceleration request from the occupant of the vehicle, When the positive motor torque decrease amount from the time point before the first reference time to the time when the regenerative state is reached is greater than or equal to the first reference value, or when the motor is in the regenerative state, When the amount of decrease in the negative motor torque until the reference time has elapsed is equal to or greater than the second reference value, the speed ratio changing process is not executed. In which, it is preferable.

Thus, before or after the time when the motor is in the regenerative state, the motor torque decrease rate (the motor torque decrease amount within the first or second reference time) is large. After a sudden deceleration, there is a high possibility that the vehicle will be accelerated to recover the speed.Therefore, it is determined that there is a high possibility that an acceleration request will occur within a predetermined time from the deceleration request. By preventing the gear ratio changing process from being executed even in the regenerative state, it is possible to improve the drivability at the time of the acceleration request after the deceleration request.

  In the hybrid vehicle control device, the vehicle further includes a descending slope determination unit that determines whether or not the traveling path on which the vehicle is traveling is a descending slope having a gradient equal to or greater than a predetermined value, and the transmission ratio changing unit includes: If the gear ratio after the change by the gear ratio changing unit is determined by the descending slope determining unit to be a descending slope having a gradient equal to or greater than a predetermined value, It is preferable that it is configured so as to be on the higher speed side.

  That is, when the traveling road on which the vehicle is traveling is a descending slope with a slope of a predetermined value or more, the speed stage at the time of acceleration request can be set to the high speed side compared to the case where it is not, and as a result, Even if there is an acceleration request after a deceleration request when the travel path is a slope with a slope of a predetermined value or more, even if the shift down amount is small, even if a higher speed ratio is set at the time of the deceleration request, the deceleration There will be no reduction in drivability when requesting acceleration after a request. In addition, by making the gear ratio on the higher speed side, the rotational speed difference between the motor-side friction plate and the engine-side friction plate in the clutch can be further reduced, and the loss in the clutch can be further reduced. It becomes possible.

  As described above, according to the hybrid vehicle control device of the present invention, when the engine is stopped by the engine controller and the clutch is released by the clutch controller, the motor controlled by the motor controller is used. When the vehicle is running, when the motor is in a regenerative state under the control of the motor control unit in response to a deceleration request from the occupant of the vehicle, the speed ratio of the automatic transmission is set to the basic ratio by the speed ratio control unit. By providing a speed ratio changing unit that executes a speed ratio changing process for changing the speed ratio to a speed ratio on the higher speed side than the basic speed ratio, when the motor is in a regenerative state, the motor in the clutch By reducing the difference in rotational speed between the friction plate on the engine side and the friction plate on the engine side, the loss in the clutch (drag loss) is reduced. Rukoto can, thus, it is possible to increase the regeneration efficiency of the motor.

It is a figure which shows the outline | summary of the system of the hybrid vehicle by which the control apparatus which concerns on embodiment of this invention is mounted. It is a flowchart which shows an example of the control in VCM. It is a time chart which shows the vehicle speed of a hybrid vehicle, an engine speed, the state of a clutch, the motor torque, the presence or absence of a gear ratio change process, and the change of the loss power in a clutch. It is a flowchart which shows another example of the control in VCM. It is a map which shows the relationship between a downward gradient and the value of a bias.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an outline of a system of a hybrid vehicle 1 (hereinafter simply referred to as a vehicle 1) equipped with a control device according to an embodiment of the present invention. The vehicle 1 includes an engine 2, a motor 3 provided on the downstream side of the power transmission path of the engine 2, and a power transmission between the engine 2 and the motor 3. And an automatic transmission 4 (hereinafter simply referred to as a transmission 4) provided on the downstream side of the power transmission path of the motor 3. The output of the transmission 4 is transmitted to the left and right drive wheels 8 (only one drive wheel 8 is shown in FIG. 1) via the differential device 6.

  The clutch C1 is a wet multi-plate clutch having a plurality of friction plates immersed in oil. The plurality of friction plates are an engine side friction plate connected to the engine 2 side and a motor connected to the motor 3 side. The engine-side friction plate and the motor-side friction plate are alternately arranged.

  When the clutch C1 is in the engaged state, the drive wheels 8 are basically driven by the engine 2 via the transmission 4, while when the clutch C1 is in the released state, the drive wheels 8 are driven by the motor 3 via the transmission 4. Drive. In the present embodiment, normally, the driving wheel 8 is driven by the motor 3, and the driving wheel 8 is driven by the engine 2 when a driving force that cannot be handled by the motor 3 is required, for example, when a predetermined acceleration or more is required. To drive. When the driving wheel 8 is driven by the engine 2, the motor 3 is driven by the engine 2 and enters a power generation state in which power is generated.

  The transmission 4 includes an input shaft 4a connected to the motor 3, an output shaft 4b connected to the differential device 6, and a plurality of power transmission paths (from the input shaft 4a to the output shaft 4b) in the transmission case 4c. A plurality of planetary gear sets (not shown) for forming a plurality of power transmission paths having different gear ratios and a power transmission path (that is, a gear ratio) by selecting one of the plurality of power transmission paths. And a clutch C2 for switching between. In FIG. 1, only one clutch C <b> 2 is drawn for the sake of simplicity, but actually there are a plurality of clutches C <b> 2, and some of the plurality may be brakes. Here, the clutch including the brake is called the clutch C2.

  The vehicle 1 includes an accelerator opening sensor 112 that detects an accelerator opening degree of the vehicle 1 (an accelerator pedal depression amount by an occupant of the vehicle 1), a vehicle speed sensor 112 that detects a vehicle speed of the vehicle 1, and a rotational speed of the engine 2. An engine speed sensor 113 for detecting the vehicle, a vehicle-to-vehicle distance sensor 114 for detecting a vehicle-to-vehicle distance between the vehicle 1 and a preceding vehicle traveling in front of the vehicle 1, and a gradient for detecting the gradient of the travel path on which the vehicle 1 travels. Various sensors such as the sensor 115 are provided, and a VCM (Vehicle Control Module) 10 to which information from these various sensors is input is provided. The VCM 10 acquires information from the various sensors, and controls the gear ratios of the engine 2, the motor 3, the clutch C1, and the transmission 4 based on these information. The VCM 10 is a known microcomputer-based control device that integrates control of individual control modules (PCM 21 and TCM 41) and controls the entire hybrid vehicle 1.

  The VCM 10 includes a central processing unit (CPU) that executes programs, a memory that is configured by, for example, RAM and ROM, and stores programs and data, and input / output (I / O) for inputting and outputting various signals. Including bus. The PCM 21 and TCM 41 have the same configuration as the VCM 10.

  In the VCM 10, an engine control unit 101 that controls the operation of the engine 2, a motor control unit 102 that controls the operation of the motor 3, a clutch control unit 103 that controls the operation of the clutch C <b> 1, and the gear ratio of the transmission 4. A transmission ratio control unit 104 for controlling the transmission ratio to be a basic transmission ratio described later, and a transmission ratio changing unit 105 for changing the transmission ratio of the transmission 4 from the basic transmission ratio by the transmission ratio control unit 104 as described later. Is provided.

  The engine control unit 101 controls the operation of the engine 2 via a PCM (Powertrain Control Module) 21. That is, the engine control unit 101 outputs an engine torque command value to the PCM 21, and the PCM 21 controls the fuel supply amount to the engine 2 so that the engine torque becomes the command value.

  A generator 22 is connected to the engine 2 via a belt 23. The generator 22 is for starting the engine 2 in a stopped state. The engine control unit 101 also controls the operation of the generator 22 via the PCM 21. That is, when the engine needs to be started, the engine control unit 101 outputs an engine ON command to the PCM 21, and in response to this, the PCM 21 starts the engine 2 by operating the generator 22.

  The motor 3 operates as an electric motor driven by electric energy charged in the battery 31 and also operates as a generator that charges the battery 31 with electric energy. The inverter 32 is controlled by the motor control unit 102 of the VCM 10 to control driving of the motor 3 and power generation by the motor 3. Specifically, when the inverter 32 receives a positive motor torque command value output from the motor control unit 102, the inverter 32 controls power supply from the battery 31 to the motor 3 so that the motor torque becomes the command value. Thereby, the motor 3 will be in a power running state. On the other hand, when the inverter 32 receives the negative motor torque command value output from the motor control unit 102, the inverter 32 generates power so that the motor torque becomes the command value, and charges the battery 31 with the generated power. Thus, the motor 3 enters a power generation state or a regeneration state in accordance with a positive or negative motor torque command value from the motor control unit 102. Thus, the motor control unit 102 controls the operation of the motor 3 via the inverter 32.

  The clutch control unit 103 outputs a clutch ON / OFF command to the clutch C1, and controls the engagement / release of the clutch C1. The clutch C1 is engaged when receiving a clutch ON command from the clutch control unit 103, and is released when receiving a clutch OFF command.

  The gear ratio control unit 104 controls the gear ratio of the transmission 4 via a TCM (Transmission Control Module) 41. That is, the gear ratio control unit 104 informs the TCM 41 of information on the required gear stage as to which gear stage (that is, gear ratio) of the transmission 4 should be set, and for each clutch C2 corresponding to this required gear stage. Clutch ON / OFF command is output. The information on the required shift speed output from the gear ratio control unit 104 to the TCM 41 depends on the traveling state of the vehicle 1 (in this embodiment, the accelerator opening by the accelerator opening sensor 111 and the vehicle speed by the vehicle speed sensor 112). This is information about a preset basic gear position (that is, a basic gear ratio). The relationship between the traveling state (accelerator opening and vehicle speed) of the vehicle 1 and the basic gear position according to the traveling state is set in advance in the map, and the gear ratio control unit 104 determines the above from the accelerator opening and the vehicle speed. The basic gear position is set using a map. The TCM 41 receives information on the basic shift speed and a clutch ON / OFF command for each clutch C2 corresponding to the basic shift speed, and controls the engagement / release of each clutch C2. The shift speed is set to the basic shift speed according to the traveling state of the vehicle 1. That is, the gear ratio control unit 104 controls the gear stage (gear ratio) of the transmission 4 so as to be the basic gear stage (basic gear ratio) corresponding to the traveling state of the vehicle 1.

  The gear ratio changing unit 105 is configured to drive the vehicle 1 by the motor 3 controlled by the motor control unit 102 when the engine 2 is stopped by the engine control unit 101 and the clutch C1 is released by the clutch control unit 103. When the motor 3 is in a regenerative state under the control of the motor control unit 102 in response to a deceleration request from the vehicle occupant, the gear ratio (transmission ratio) of the transmission 4 is changed by the transmission ratio control unit 104. A gear ratio changing process for changing to a gear speed (speed ratio) on the higher speed side than the basic gear speed (basic speed ratio) is executed. Then, the gear ratio changing unit 105 outputs, to the TCM 41, information on the changed gear stage as information on the required gear stage as to which gear stage of the transmission 4 should be changed. A clutch ON / OFF command to each clutch C2 corresponding to the gear position is output. When the gear ratio changing process is executed by the gear ratio changing unit 105, assuming that the basic gear stage by the gear ratio control unit 104 is, for example, the third speed when the motor 3 is in the regenerative state, the transmission 4 Is changed from the third speed, which is the basic speed, to, for example, the fourth speed or the fifth speed (upshifted by, for example, one or two stages with respect to the basic speed).

In the present embodiment, the VCM 10 includes an acceleration request possibility determination unit 106 that determines whether or not there is a high possibility that an accelerating request for an occupant of the vehicle 1 within a predetermined time from the deceleration request, and the vehicle 1 travels. A downhill road determination unit 107 is further provided for determining whether or not the running road is a downhill road having a gradient equal to or greater than a predetermined value. The acceleration request possibility determination unit 106 and the downhill determination unit 107 are not essential, and either or both of them may be omitted.

  For example, the acceleration request possibility determination unit 106 determines that the possibility is high when the inter-vehicle distance detected by the inter-vehicle distance sensor 114 is equal to or less than a predetermined distance. That is, in a situation where the inter-vehicle distance between the vehicle 1 and the preceding vehicle ahead thereof is equal to or less than the predetermined distance, the vehicle 1 travels following the preceding vehicle, and acceleration and deceleration are repeated frequently. Since there is a high possibility that it will be performed, it is determined that there is a high possibility that an acceleration request will occur within the predetermined time from the deceleration request.

  Instead of this, or in addition to this, the acceleration request possibility determination unit 106 switches the motor 3 from the positive value to the negative value when the motor 3 enters the regenerative state as described above. When the motor torque decreasing speed is large before and after the time point (hereinafter referred to as switching time point), it may be determined that the possibility of an acceleration request within the predetermined time from the deceleration request is large. That is, when the positive motor torque decrease amount ΔT1 from the time point before the first reference time (for example, 1 second to several seconds) to the switching time point to the switching time point is equal to or greater than the first reference value Ta, It is determined that there is a high possibility of an acceleration request within the predetermined time from the deceleration request. Also, the negative motor torque decrease amount ΔT2 (increment amount in terms of the absolute value of the motor torque) between the switching time and the elapse of the second reference time (for example, 1 second to several seconds) is equal to or greater than the second reference value Tb. In this case, it is determined that there is a high possibility of an acceleration request within the predetermined time from the deceleration request. As described above, the fact that the motor torque decrease speed (the motor torque decrease amount within the first or second reference time) is large means that rapid deceleration has been performed. Since there is a high possibility that the vehicle will be accelerated to recover, it is determined that there is a high possibility that an acceleration request will occur within the predetermined time from the deceleration request. On the other hand, when the vehicle is slowly decelerating, it can be determined that the deceleration continues for the predetermined time or longer (no acceleration request is generated), and it is determined that the possibility is not great.

  Based on the information from the gradient sensor 115, the downhill determination unit 107 determines whether or not the traveling road on which the vehicle 1 is traveling is a downhill road having a gradient greater than or equal to a predetermined value. In addition, an acceleration sensor is provided instead of the gradient sensor 115, and it is determined whether or not the traveling road is a downhill road having a gradient of a predetermined value or more from information from the acceleration sensor and the vehicle speed sensor and the motor torque. You may do it.

  The gear ratio changing unit 105 is configured such that the engine 2 is stopped by the engine control unit 101 and the clutch C1 is released by the clutch control unit 103, and the vehicle 1 is driven by the motor 3 controlled by the motor control unit 102. In the case where the acceleration request possibility determination unit 106 determines that the possibility is high even if the motor 3 is in a regenerative state by the control of the motor control unit 102 due to the deceleration request of the occupant of the vehicle 1 Is configured not to execute the gear ratio changing process.

  That is, when the motor 3 is in the regenerative state and the speed ratio changing process is executed to set the speed ratio on the high speed side, if there is an acceleration request within the predetermined time period, It is necessary to switch (shift down) from the speed ratio on the side to the speed ratio on the low speed side, and a large shift down occurs in a short time after the shift up, resulting in a decrease in drivability. In the present embodiment, in order to prevent such a decrease in rivability, the gear ratio changing unit 105 performs a gear ratio changing process when the acceleration request possibility determining unit 106 determines that the possibility is high. Do not execute.

  Further, the gear ratio changing unit 105 determines that the gear ratio after the change by the gear ratio changing unit 105 is a downhill road in which the traveling road has a slope greater than or equal to the predetermined value by the downhill road judgment unit 107. In some cases, the speed is set higher than in the case where it is determined that this is not the case. For example, when the traveling road is not a downhill road having a gradient equal to or higher than the predetermined value (that is, a flat road or an uphill road), the gear position of the transmission 4 is shifted by one stage with respect to the basic gear position. In the case where the gear is shifted up and the traveling road is a downhill road having a slope greater than or equal to the predetermined value, the gear is shifted up by two from the basic gear.

  In other words, when the traveling road is a downhill road having a slope equal to or greater than a predetermined value, the speed stage at the time of requesting acceleration can be set to a higher speed than when the traveling road is not, and as a result, the traveling road is predetermined. Even if there is an acceleration request after a deceleration request in the case of a downhill road with a slope greater than the value, even if the shift down amount is small, even if the higher speed ratio is set at the time of the deceleration request, There will be no decrease in drivability when acceleration is requested. In addition, the loss in the clutch C1 can be further reduced by setting the gear ratio on the higher speed side.

  Next, an example of control in the VCM 10 (control related to change of the gear ratio when the motor 3 is in the regenerative state) will be described based on the flowchart of FIG.

  In the first step S1, information is acquired from various sensors, and in the next step S2, it is determined whether or not the engine 2 is in a stopped state. When the determination in step S2 is NO, the process proceeds to step S3, where the gear ratio control unit 104 sets the gear position of the transmission 4 to the basic gear position, and then returns.

  When the determination in step S2 is YES, the process proceeds to step S4 to determine whether or not the clutch C1 is in a released state. When the determination in step S4 is NO, the process proceeds to step S3.

  When the determination in step S4 is YES, the process proceeds to step S5, and it is determined whether or not the motor 3 is in a regenerative state according to a deceleration request from the occupant of the vehicle 1. When the determination in step S5 is NO, the process proceeds to step S3.

When the determination in step S5 is YES, the process proceeds to step S6, and in the acceleration request possibility determination unit 106, is there a high possibility that an acceleration request from the occupant of the vehicle 1 within the predetermined time from the deceleration request is generated? (For example, whether the inter-vehicle distance detected by the inter-vehicle distance sensor 114 is equal to or less than the predetermined distance). When the determination in step S6 is YES, the process proceeds to step S3.

  When the determination in step S6 is NO, the process proceeds to step S7, and the downhill road determination unit 107 determines whether or not the road on which the vehicle 1 is traveling is a downhill road having a gradient greater than the predetermined value. judge.

  When the determination in step S7 is NO, the process proceeds to step S8, and the gear ratio changing unit 105 sets the gear position of the transmission 4 to a gear position shifted up by one step from the basic gear speed, and then Return. On the other hand, when the determination in step S7 is YES, the process proceeds to step S9, where the gear ratio changing unit 105 sets the gear position of the transmission 4 to a gear position shifted up by two from the basic gear speed. Then return.

  In steps S7 and S8, the gear ratio changing unit 105 executes a gear ratio changing process for changing the gear position of the transmission 4 to a gear ratio on the higher speed side than the basic gear ratio. The shift stage is shifted up by one stage or two stages. The gear ratio after the change by the gear ratio changing unit 105 is determined when the downhill road determination unit 107 determines that the travel road is a downhill road having a gradient equal to or greater than the predetermined value (YES in step S7). In some cases, compared to the case where it is determined that this is not the case (when the determination in step S7 is NO), the speed is increased.

  Here, it is assumed that the vehicle speed, the engine speed, the state of the clutch C1 (engaged state or released state), and the motor torque of the vehicle 1 are changed as shown in FIG. That is, until time t1, the vehicle is accelerating due to the acceleration request of the occupant 1 and cannot be handled by the motor 3 at this time. Therefore, the engine 2 drives the drive wheels 8, and the motor 3 is in a power generation state. (The motor torque is negative). Eventually, the required level of acceleration becomes smaller, and at time t1, the motor 3 is switched to traveling (the motor torque becomes a positive value). As a result, the engine 2 is stopped and the clutch C1 is released.

  From time t1 to time t2, the required level of acceleration gradually decreases and the positive motor torque gradually decreases. Then, at time t2, the request changes to a deceleration request, whereby the motor 3 enters a regenerative state (the motor torque changes from a positive value to a negative value). In this example, the reduction amount ΔT1 is not a sudden deceleration, and the decrease amount ΔT1 is smaller than the first reference value Ta, and the decrease amount ΔT2 is smaller than the second reference value Tb. That is, the acceleration request possibility determination unit 106 does not determine that the possibility of an acceleration request within the predetermined time from the deceleration request (time t2) is high.

  Then, as shown in the graph in the second column from the bottom of FIG. 3, at the time t2, the gear ratio changing process by the gear ratio changing unit 105 is executed (for example, one step up with respect to the basic gear). The gear ratio changing process continues until time t3. The time (t3-t2) between time t3 and time t2 is longer than the predetermined time. Assuming that the gear ratio changing process is not executed from time t2 to time t3 as indicated by a two-dot chain line in the graph of the second column from the bottom in FIG. 3, the loss power in the clutch C1 is as shown in FIG. As shown by the two-dot chain line in the lowermost graph, the loss power at the clutch C1 is changed as shown by the solid line in the lowermost graph when the gear ratio change process is executed. This is lower than when the gear ratio changing process is not executed. When the clutch C1 is in the engaged state (before time t1 and after time t4), the loss power in the clutch C1 becomes zero.

  At time t3, an acceleration request is made again, and the motor torque switches from a negative value to a positive value. At time t4, the motor 3 cannot respond, so the engine 2 is started, the clutch C1 is engaged, and the engine 2 To drive the drive wheel 8. At this time, the motor 3 is in a power generation state (the motor torque is a negative value) as before time t1.

  Next, another example of control in the VCM 10 will be described based on the flowchart of FIG.

  In steps S21 to S25, processing operations similar to those in steps S1 to S5 are executed, respectively. When the determination in step S25 is NO, the process proceeds to step S23, and the shift stage of the transmission 4 is set to the basic shift stage. Then return. On the other hand, when the determination in step S25 is YES, the process proceeds to step S26.

  In step S26, the decrease amount ΔT1 is calculated, and in the next step S27, it is determined whether or not the decrease amount ΔT1 is equal to or greater than the first reference value Ta. When the determination in step S27 is YES, the process proceeds to step S23.

  On the other hand, when the determination in step S27 is NO, the process proceeds to step S28 to calculate the amount of decrease ΔT2, and in the next step S29, whether or not the amount of decrease ΔT2 is greater than or equal to the second reference value Tb. Determine. When the determination in step S29 is YES, the process proceeds to step S23.

  On the other hand, when the determination in step S29 is NO, the process proceeds to step S30 to calculate the first loss power. This first loss power is the total loss power including the loss power in the clutch C1, the loss power in the motor 3, and the loss power in the transmission 4 when the transmission gear 4 is set to the basic shift speed. It is. The loss power at the clutch C1, the loss power at the motor 3, and the loss power at the transmission 4 are stored in the memory of the VCM 10 for each gear position of the transmission 4.

  In the next step S31, the second loss power is calculated. The second loss power is a value obtained by adding a bias amount for considering a downward gradient to the total loss power when the shift stage of the transmission 4 is shifted up by one stage from the basic shift stage.

  In the next step S32, the third loss power is calculated. The third loss power is a value obtained by adding the bias amount to the total loss power when the shift stage of the transmission 4 is shifted to a shift stage that is shifted up by two stages with respect to the basic shift stage.

  The bias value is stored in the memory of the VCM 10 as a map as shown in FIG. 5, for example. According to this, the value of the bias decreases as the descending slope increases, and the bias when the shift stage of the transmission 4 is shifted to a shift stage that is one step up from the basic shift stage. This is smaller than the bias when the shift stage is shifted up by two stages.

  In the next step S33, the minimum loss power is selected from the first loss power, the second loss power, and the third loss power, and the shift speed that provides the minimum loss power is selected.

  In the next step S34, it is determined whether or not the number of rotations of the motor 3 at the shift speed at which the minimum loss power is obtained is greater than a predetermined number of rotations. That is, if the rotational speed of the motor 3 is equal to or lower than the predetermined rotational speed, the engine 2 cannot output the required torque when the clutch C1 is engaged. In order to prevent such a low rotational speed, The determination in step S34 is performed. The predetermined rotation speed is, for example, 1000 rpm.

  When the determination in step S34 is NO, the shift stage is shifted down by one stage with respect to the shift stage having the minimum loss power, and the process proceeds to step S36. On the other hand, if the determination in step S34 is YES, the process proceeds directly to step S36.

  In step S36, it is determined whether the inter-vehicle distance detected by the inter-vehicle distance sensor 114 is equal to or less than the predetermined distance. If the determination in step S36 is YES, the process proceeds to step S23. If the determination in step S36 is NO, the process returns.

  In another example of the above control, the speed of the transmission 4 when the motor 3 is in the regenerative state is set to the speed with the smallest total loss power. The power loss at 3 and the power loss at the transmission 4 do not vary greatly depending on the shift speed, and the loss power of the clutch C1 varies greatly depending on the shift speed. 2 Loss power becomes small, and 3rd loss power becomes smaller than 2nd loss power. However, due to the bias, the third loss power is larger than the second loss power and the second loss power is the smallest on a flat road or a downhill road close to the predetermined value, for example, on a downhill road close thereto. Thus, the third loss power becomes the smallest when the downward gradient is equal to or greater than the predetermined value. As a result, the gear ratio changing unit 105 changes the gear stage of the transmission 4 to a gear stage shifted up by one or two stages with respect to the basic gear stage. When it is determined that the traveling road that is running is a downhill road having a slope greater than or equal to the predetermined value, the road is on the higher speed side than when it is determined that it is not.

  Even if the speed of the transmission 4 is changed to a speed that is shifted up by one or two stages relative to the basic speed, the minimum loss power can be obtained as long as the rotational speed of the motor 3 is not more than a predetermined speed. Thus, the shift stage is shifted down by one stage with respect to the shift stage.

In another example of the control, the steps S27, S29, and S36 may cause an acceleration request of the occupant of the vehicle 1 within the predetermined time from the deceleration request in the acceleration request possibility determination unit 106. This corresponds to the determination of whether or not it is large, and when it is determined that the possibility is high (when the determinations in steps S27, S29, and S36 are YES), the transmission ratio change unit 105 performs the transmission ratio change. The process is not executed, and the shift speed of the transmission 4 is set to the basic shift speed.

  Therefore, in the present embodiment, when the engine 2 is stopped and the clutch C1 is in the disengaged state, when the vehicle 1 is traveling by the motor 3, the motor control unit is controlled by a deceleration request from the occupant of the vehicle 1. When the motor 3 is in the regenerative state by the control by 102, the transmission ratio changing unit 105 changes the transmission ratio of the transmission 4 from the basic transmission ratio by the transmission ratio control unit 104 to a higher-speed shift than the basic transmission ratio. Since the gear ratio changing process for changing to the ratio is executed, when the motor 3 is in the regenerative state, the rotational speed of the input shaft of the transmission 4, that is, the rotational speed of the motor 3 is changed to the speed ratio changing process. As a result, the rotational speed difference between the motor friction plate and the engine-side friction plate in the clutch C1 is reduced, and as a result, the loss in the clutch C1 ( Sliding loss can) is reduced. The travel resistance of the vehicle 1 is reduced by the amount of the loss in the clutch C1, so that the regeneration efficiency of the motor 3 can be increased.

  The present invention is not limited to the embodiment described above, and can be substituted without departing from the spirit of the claims.

  The above-described embodiments are merely examples, and the scope of the present invention should not be interpreted in a limited manner. The scope of the present invention is defined by the scope of the claims, and all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  The present invention relates to an engine, a motor provided downstream of the power transmission path of the engine, a clutch provided between the engine and the motor, and an automatic provided downstream of the power transmission path of the motor. This is useful for a control device of a hybrid vehicle including a transmission.

DESCRIPTION OF SYMBOLS 1 Hybrid vehicle 2 Engine 3 Motor 4 Automatic transmission 10 VCM (control apparatus)
DESCRIPTION OF SYMBOLS 101 Engine control part 102 Motor control part 103 Clutch control part 104 Transmission ratio control part 105 Transmission ratio change part 106 Acceleration request possibility determination part 107 Downhill road determination part C1 Clutch which connects / disconnects power transmission between an engine and a motor

Claims (4)

An engine, a motor provided downstream of the power transmission path of the engine, a clutch for connecting / disconnecting power transmission between the engine and the motor, and an automatic provided downstream of the power transmission path of the motor A control device for a hybrid vehicle comprising a transmission,
An engine control unit for controlling the operation of the engine;
A motor control unit for controlling the operation of the motor;
A clutch control unit for controlling the operation of the clutch;
A gear ratio control unit for controlling the gear ratio of the automatic transmission to a preset basic gear ratio according to the traveling state of the vehicle;
When the vehicle is running by the motor controlled by the motor control unit when the engine is stopped by the engine control unit and the clutch is released by the clutch control unit, When the motor is in a regenerative state under the control of the motor control unit in response to a deceleration request from a vehicle occupant, the speed ratio of the automatic transmission is changed from the basic speed ratio by the speed ratio control unit to the basic speed ratio. A control apparatus for a hybrid vehicle, comprising: a gear ratio changing unit that executes a gear ratio changing process for changing to a higher gear ratio. In the hybrid vehicle control device according to claim 1,
An inter-vehicle distance sensor for detecting an inter-vehicle distance between the vehicle and a preceding vehicle traveling in front of the vehicle ;
The speed ratio changing unit is configured such that the vehicle is driven by the motor controlled by the motor control unit when the engine is stopped by the engine control unit and the clutch is released by the clutch control unit. When the vehicle distance detected by the inter-vehicle distance sensor is equal to or less than a predetermined distance even when the motor is in a regenerative state under the control of the motor control unit due to a deceleration request from the vehicle occupant The hybrid vehicle control device is configured not to execute the speed ratio changing process. In the hybrid vehicle control device according to claim 1,
The speed ratio changing unit is configured such that the vehicle is driven by the motor controlled by the motor control unit when the engine is stopped by the engine control unit and the clutch is released by the clutch control unit. Even when the motor is in the regenerative state by the control of the motor control unit due to the deceleration request of the vehicle occupant, the time point before the first reference time with respect to the time point when the motor is in the regenerative state When the positive motor torque decrease amount from the time when the motor enters the regenerative state to the first reference value or more, or from the time when the motor enters the regenerative state until the second reference time elapses. The hybrid vehicle is configured not to execute the speed ratio changing process when the amount of decrease in the negative motor torque is equal to or greater than the second reference value. The control device. In the control apparatus of the hybrid vehicle as described in any one of Claims 1-3,
A further downhill road determination unit for determining whether or not the road on which the vehicle is running is a downhill road having a gradient equal to or greater than a predetermined value;
The gear ratio changing unit determines the gear ratio after the change by the gear ratio changing unit when the downhill road judging unit determines that the travel road is a downhill road having a gradient greater than or equal to a predetermined value. A control device for a hybrid vehicle, characterized in that the control device is configured to be on the high speed side as compared to a case where it is determined that it is not.

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