JP6658170B2 - Engine stop control device for hybrid vehicle - Google Patents

Description

  The present invention relates to an engine stop control device for a hybrid vehicle, and more particularly to a technique for suppressing generation of abnormal noise such as rattling noise when stopping rotation of an engine.

  (a) a power split section that splits the power transmitted from the engine into a first rotating machine and an output member, and outputs the power to the drive wheel from the output member; and (b) the drive wheel through a mechanical meshing mechanism. Or a second rotating machine that outputs power to the other drive wheels, and (c) the first rotating machine of the first rotating machine through a predetermined preparation such as a fuel cut or a torque change while the vehicle is running. There is known an engine stop control device in which the rotation speed of the engine is reduced by torque control to stop the rotation, and the driving force fluctuation caused by the torque control is compensated by the second rotating machine. The device described in Patent Literature 1 is an example of such a device. In order to prevent an intermittent operation in which an engine is automatically stopped while a vehicle is running and a driving force increases due to a reaction force when the engine stops rotating. The torque of the second rotating machine is reduced to compensate. Further, when the power running torque of the second rotating machine is reduced in this way, if the torque of the second rotating machine reaches near 0 or shifts below 0 to the regenerative side, mechanical engagement occurs. Since the mechanism (reduction gear, etc.) is in a floating state to generate gar noise (also referred to as jarring noise), or the direction of the transmitted torque is reversed to generate rattling noise, the vehicle speed is low and the predetermined speed is low. The intermittent operation is prohibited in the case of the driving force range described above.

JP 2006-257894 A

  However, when traveling resistance is high, such as when climbing a hill or towing (towing), the vehicle travels with a relatively large driving force, so that intermittent operation is permitted even at low vehicle speeds, and engine rotation stop control is permitted. If the driving force suddenly decreases due to the operation of returning the accelerator during the control process, the torque of the second rotating machine decreases to around 0 or less, generating abnormal noises such as garbling noise and rattling noise, causing the passenger to feel uncomfortable. There was a possibility. In order to prevent this, it is conceivable to expand the driving force range in which intermittent operation is prohibited, but intermittent operation is also prohibited except when the driving force suddenly decreases, which may cause abnormal noise such as rattling noise. This will result in poor fuel economy.

  In the case of normal running resistance such as on a flat road, the vehicle speed is rapidly increased by a large driving force, and abnormal noise such as rattling noise is buried by running noise. Even if abnormal noise such as rattling noise is generated due to a sudden decrease in force, there is no danger that the occupant will feel uncomfortable. This is a particular problem when running resistance is large and vehicle speed is difficult to increase.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to allow rattling noise due to a decrease in driving force while permitting engine rotation stop control during traveling with large traveling resistance. It is to appropriately suppress the generation of abnormal noise such as.

The present invention provides (a) a power splitting unit that splits the power transmitted from an engine into a first rotating machine and an output member, and outputs the power to the drive wheels from the output member; and (b) a power splitting unit through a mechanical engagement mechanism. A second rotating machine that outputs power to the driving wheels or other driving wheels. (C) While the vehicle is traveling, the torque is controlled by the first rotating machine through a predetermined preparation. In the engine stop control device for performing rotation stop control in which the rotation speed of the engine is reduced to stop the rotation and the driving force fluctuation caused by the torque control is compensated by the second rotating machine, When the resistance satisfies a predetermined resistance determination condition, a change rate of the driving force command value or the driving force request value, and a predetermined preparation time required for the preparation , after the preparation , The rotation stop control estimates the driving force when executed, that when estimated estimated driving force is a driving force is within a predetermined limited range greater than 0 limits the rotation stop control in It has a rotation stop restriction part.

  The predetermined preparation is a process before stopping the engine rotation, such as a fuel cut for stopping the fuel supply to the engine and a drive source transfer process for switching the driving force of the engine to the torque of the second rotating machine. is there. In addition, the limited range of the estimated driving force is such that when the torque of the second rotating machine is close to 0 and the mechanical meshing mechanism is in a floating state, the garbled sound generated and the torque of the second rotating machine are 0. It is desirable to set so as to avoid both rattling noises that occur when the direction of the transmission torque of the mechanical meshing mechanism reverses due to the change to the regenerative side beyond It may be set so that it can be performed. Further, instead of the estimated driving force, it is also possible to use another physical quantity such as an estimated driving torque that changes according to the driving force or a torque of the second rotating machine controlled according to the driving force. Also, the rotation stop control is substantially limited based on the estimated driving force, which belongs to the technical scope of the present invention.

  According to such an engine stop control device for a hybrid vehicle, when the running resistance is large, the driving force when the rotation stop control of the engine is executed is estimated, and the estimated driving force is set to a predetermined limited range. When the rotation speed is within the range, the rotation stop control is restricted, so that the driving force is rapidly reduced by the operation of returning the accelerator or the like, and the torque of the second rotating machine is reduced to around 0 or less by compensation at the time of the engine rotation stop control. In such a case, the rotation stop control is limited before the rotation stop control of the engine is actually executed, so that generation of abnormal noise such as rattling noise can be appropriately suppressed. Further, since the rotation stop control is limited based on the estimated driving force, the fuel consumption performance is appropriately secured as compared with the case where the stop control (intermittent operation) of the engine is uniformly prohibited when the running resistance is large.

FIG. 1 is a skeleton diagram of a hybrid vehicle to which the present invention is applied, and also shows a main part of a control system. 2 is a flowchart specifically illustrating signal processing (operation) performed by the intermittent operation restriction unit in FIG. 1. 3 is a time chart illustrating a case where intermittent operation is prohibited according to the flowchart of FIG. 2. FIG. 7 is a view for explaining another embodiment of the present invention, and is a flowchart corresponding to FIG. 2. 5 is a time chart for explaining a case where an intermittent operation is performed with a reduction torque reduced according to the flowchart of FIG. 4.

  As the power split unit, a single pinion type or double pinion type planetary gear device is preferably used, but a paired rotor motor having an inner rotor and an outer rotor can also be used, and the engine is mounted on one of the rotors. The output member is connected to the other. The anti-rotor motor can selectively output the powering torque and the regenerative torque similarly to the motor generator, and also functions as the first rotating machine. A clutch, a speed change gear, and the like may be provided at a connection portion between the power split unit and the engine or the output member, if necessary.

  As the first rotating machine and the second rotating machine, a motor generator which can be selectively used as an electric motor and a generator is appropriate. However, a generator is adopted as the first rotating machine and an electric motor is used as the second rotating machine. A motor can also be employed. The mechanical meshing mechanism between the second rotating machine and the drive wheels generates a gurgling noise or rattling noise when the transmission torque is in a floating state where the transmission torque is substantially zero or when the transmission torque changes over the zero torque. And a transmission gear mechanism or a spline coupling mechanism having a backlash.

The rotation stop restriction unit may limit the rotation stop control based only on the estimated driving force, but may also limit the rotation stop control based on, for example, that the vehicle speed is equal to or less than a predetermined upper limit determination value as an and condition. etc. can, Ru can be provided various other and conditions or or conditions.

  The present invention relates to a hybrid vehicle that performs an intermittent operation in which the engine is stopped while the vehicle is operating, for example, an EV driving mode in which the engine is stopped and the second rotating machine is driven as a drive source, and an engine drive mode in which the engine is driven as a drive source. The engine stop control device executes control when the engine is stopped in the intermittent operation. In this case, the rotation stop restriction unit is configured to, for example, prohibit the intermittent operation and maintain the operation state of the engine (such as an idle operation state), but continue the intermittent operation (operation stop of the engine). On the other hand, the rotation stop control for reducing the engine rotation speed by the first rotating machine may be simply prohibited.

  The rotation stop restriction unit is configured to, for example, prohibit the intermittent operation or prohibit the rotation stop control. However, when the rotation stop control is performed, the torque of the first rotating machine, that is, the reduction speed of the engine rotation speed is reduced. May be limited so that the torque of the second rotating machine does not decrease to around 0 or less.

  The rotation stop restriction unit of the present invention restricts the rotation stop control under a certain condition when the running resistance is large, but regardless of the running resistance, the vehicle speed is equal to or less than a predetermined second upper limit determination value, Further, when the driving force (for example, a command value or a required value) is within a predetermined second restriction range larger than 0, a second rotation stop restriction unit that restricts the rotation stop control may be provided. . In that case, it is desirable to first determine whether or not to restrict the rotation stop control by the second rotation stop restriction unit, and to perform the processing by the rotation stop restriction unit of the present invention when the rotation stop control is not restricted.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a skeleton diagram illustrating a schematic configuration of a hybrid vehicle 10 having an engine stop control device according to an embodiment of the present invention, and also shows a main part of a control system for controlling each part of the hybrid vehicle 10. FIG. The hybrid vehicle 10 is an FF (front engine / front drive) type and includes an engine (ENG) 12 used as a drive source for traveling and a transaxle 14 as a power transmission device. The engine 12 is an internal combustion engine such as a gasoline engine and a diesel engine. The transaxle 14 includes a damper 18, an input shaft 20, a power split mechanism 22, a counter gear pair 24, a final gear pair 26, and a differential gear in a case 16 as a non-rotating member attached to a vehicle body, in order from the engine 12. A device (final speed reducer) 28 and the like are provided.

  Power split device 22 corresponds to a power split unit, and splits the power output from engine 12 to first motor generator MG1 and output gear 30. A second motor generator MG2 is connected to the output gear 30 via a transmission gear mechanism 34 functioning as a speed reducer. Each of the first motor generator MG1 and the second motor generator MG2 can be selectively used as an electric motor that generates a power running torque and a generator that generates a regenerative torque, and the first motor generator MG1 has a first rotation. And the second motor generator MG2 corresponds to a second rotating machine. The output gear 30 corresponds to an output member, and the transmission gear mechanism 34 corresponds to a mechanical meshing mechanism.

  The counter gear pair 24 includes the output gear 30 and a counter driven gear 36. One end of the input shaft 20 is connected to the engine 12 via the damper 18, and is driven to rotate by the engine 12. An oil pump 38 is connected to the other end of the input shaft 20. The rotation of the input shaft 20 causes the oil pump 38 to rotate, thereby driving each part of the transaxle 14, for example, the power split mechanism 22, Lubricating oil is supplied to a gear meshing portion, a bearing portion, and the like of the transmission gear mechanism 34.

  In such a transaxle 14, the power of the engine 12 and the power of the second motor generator MG2 input via the damper 18 and the input shaft 20 are transmitted from the output gear 30 to the counter gear pair 24, the final gear pair 26, The power is transmitted to a pair of front drive wheels 40 via a gear device 28, a pair of axles, and the like.

  The power split device 22 is a single pinion type planetary gear device including three rotating elements of a first sun gear S1, a first carrier CA1, and a first ring gear R1, and the first carrier CA1 is connected to the input shaft 20, that is, to the engine 12. The first sun gear S1 is connected to the first motor generator MG1, and the first ring gear R1 is connected to the output gear 30. The first sun gear S1, the first carrier CA1, and the first ring gear R1 can rotate relative to each other, so that the output of the engine 12 is divided into the first motor generator MG1 and the output gear 30, and the first motor The first motor generator MG1 is rotated by the power of the engine 12 divided into the generator MG1 to generate power, and the generated electric energy is stored in the power storage device 52 via the inverter 50, or The second motor generator MG2 is rotationally driven by the energy. That is, the power split device 22 is in a continuously variable transmission state (electric CVT state), and the electric continuously variable transmission in which the gear ratio γ0 (= engine rotation speed Ne / output rotation speed Nout) is continuously changed. Function as This type of hybrid type is called a machine split type or a split type.

  The transmission gear mechanism 34 is a single pinion type planetary gear device including three rotating elements of a second sun gear S2, a second carrier CA2, and a second ring gear R2, and the second carrier CA2 is a case 16 that is a non-rotating member. The second sun gear S2 is connected to the second motor generator MG2, and the second ring gear R2 is connected to the output gear 30. The transmission gear mechanism 34 functions as a speed reducer, and when the second motor generator MG2 outputs a torque during power running, the rotation of the second motor generator MG2 is adjusted to a gear ratio (= the number of teeth of the sun gear S2 / the number of teeth of the ring gear R2). Accordingly, the torque is increased, and the torque is increased and transmitted to output gear 30. The second motor generator MG2 functions as a driving source for traveling, and in this embodiment, drives the front drive wheel 40 in the same manner as the engine 12, but the engine 12 drives the front drive wheel 40 to rotate, and the second motor Generator MG2 may be configured to rotationally drive the rear wheels.

  The hybrid vehicle 10 configured as described above includes the electronic control device 80. The electronic control unit 80 is configured to include a so-called microcomputer having a CPU, a ROM, a RAM, and an input / output interface, and performs signal processing according to a program stored in the ROM in advance while using the temporary storage function of the RAM. By doing so, it functions as a controller that controls the operating states of engine 12 and motor generators MG1, MG2. The electronic control unit 80 receives an engine rotation speed sensor 60, an output rotation speed sensor 62, an MG1 rotation speed sensor 64, an MG2 rotation speed sensor 66, an accelerator operation amount sensor 68, a tilt sensor 70, and an SOC sensor 72 from the engine 12 respectively. Rotation speed (engine rotation speed) Ne, rotation speed of output gear 30 (output rotation speed) Nout, rotation speed of first motor generator MG1 (MG1 rotation speed) Nmg1, rotation speed of second motor generator MG2 (MG2 rotation speed) Nmg2, an accelerator pedal operation amount (accelerator operation amount) Acc, a road surface gradient Φ, a signal indicating the remaining power SOC of the power storage device 52 are supplied, and various information necessary for various controls is supplied. Has become. The output rotation speed Nout corresponds to the vehicle speed spd.

  The electronic control unit 80 has a hybrid control unit 82 functionally. The hybrid control unit 82 calculates the required driving force of the hybrid vehicle 10 by the driver based on, for example, the accelerator operation amount Acc and the vehicle speed spd, and considers the required charging amount of the power storage device 52 and the like, and calculates the required driving force and the required driving force. Engine 12 and motor generators MG1 and MG2 are controlled so as to obtain a charge amount. The hybrid control unit 82 also stops the operation of the engine 12 and executes an EV running (motor running) in which only the second motor generator MG2 is used as a drive source for running. By transmitting the power by the power generation of the first motor generator MG1, the motive power of the engine 12 is transmitted to the output gear 30, and the power generated by the first motor generator MG1 drives the second motor generator MG2 to generate a torque on the output gear 30. And selectively establishes an engine traveling mode or the like for executing an engine traveling in which the vehicle travels using at least the engine 12 as a traveling drive source in accordance with the driving state. In the engine traveling mode, assist traveling can be performed in which the vehicle travels by adding the power of second motor generator MG2 using the electric power from power storage device 52.

  The running modes such as the EV running mode and the engine running mode are switched according to a predetermined mode switching map or the like using the operating state such as the vehicle speed spd and the required driving force as parameters. By switching the traveling mode in this manner, intermittent control for automatically stopping the engine 12 during vehicle operation is performed. In this intermittent control, the operation of the engine 12 is stopped by fuel cut or the like, and a drive source transfer process for replacing the driving force by the engine 12 with the torque of the second motor generator MG2 is performed. Further, by controlling the regenerative torque or the powering torque of the first motor generator MG1, the rotation stop control for forcibly reducing the engine rotation speed Ne and stopping the rotation immediately is performed. At this time, a rotational torque corresponding to the torque of the first motor generator MG1 is added to the output gear 30 by the reaction force due to the inertia of the engine 12, and the driving force is increased by that amount, so that the power running of the second motor generator MG2 is performed. Compensation control is performed to reduce the torque and suppress fluctuations in the driving force. The hybrid control unit 82 has a function of an intermittent operation control unit that stops the engine 12.

  Here, when the powering torque of the second motor generator MG2 is reduced to suppress the fluctuation of the driving force, the torque (MG2 torque) of the second motor generator MG2 becomes close to 0 as shown in a time chart of FIG. 3, for example. When the speed reaches the regenerative torque side after reaching 0 or the regenerative torque side, the speed change gear mechanism 34 to which the second motor generator MG2 is connected is brought into a floating state to generate gar noise, or the speed change gear mechanism 34 The direction of the transmitted torque may be reversed, and a rattling noise may be generated. In order to prevent this, the electronic control unit 80 is functionally provided with an intermittent operation restriction unit 84, which restricts the intermittent operation under predetermined conditions. The intermittent operation restriction unit 84 constitutes an engine stop control device together with the hybrid control unit 82.

  The intermittent operation restriction unit 84 performs signal processing according to steps S1 to S8 (hereinafter, simply referred to as S1 to S8) of the flowchart shown in FIG. The intermittent operation restriction unit 84 includes a basic restriction unit 86 and a high resistance restriction unit 88. S3 and S7 in FIG. 2 correspond to the basic restriction unit 86, and S4 to S7 correspond to the high resistance restriction unit 88. However, the high-resistance limiting section 88 functions as the rotation stop limiting section of the present invention.

  The flowchart of FIG. 2 is executed, for example, when the hybrid control unit 82 makes an intermittent engine determination for stopping the engine 12, such as a mode switching determination for shifting from the engine traveling mode to the EV traveling mode. It is determined whether or not the vehicle is running, for example, based on the vehicle speed spd or the like. If the vehicle is not running, S8 is executed to permit execution of the engine intermittent control (stop control). If the vehicle is running, S2 is executed. In S2, it is determined whether or not the engine 12 is operating based on the presence or absence of fuel injection control. If not, S8 is executed. If it is operating, S3 is executed.

In S3, it is determined whether or not a predetermined basic intermittent prohibition condition is satisfied. This intermittent prohibition condition is the same as that conventionally performed. Specifically, it is determined whether or not both of the following equation (1) regarding the driving force command value TP and the following equation (2) regarding the vehicle speed spd are satisfied. to decide. Equation (1) indicates that the powering torque of the second motor generator MG2, which is controlled according to the driving force command value TP after the engine is stopped, decreases to around 0 or less as shown in FIG. When there is a possibility that a girling noise or a rattling noise may occur, the driving force lower limit determination threshold value TPmin and the driving force upper limit determination threshold value TPmax are determined in advance by experiments and the like in consideration of a change in the driving force. For example, 0 is set as the driving force lower limit determination threshold TPmin. The driving force upper limit determination threshold value TPmax is appropriately determined according to the torque reduction amount of the second motor generator MG2 during the compensation control, that is, the torque of the first motor generator MG1 when the engine rotation speed Ne is forcibly reduced. If the torque of the first motor generator MG1 is constant, the driving force upper limit determination threshold value TPmax may be a constant value. If the torque of the first motor generator MG1 is variably set, the driving force upper limit determination threshold value is set according to the torque. It is desirable that TPmax is also variably set. If only the garbled noise is to be avoided, a relatively narrow range in which the torque of the second motor generator MG2 is close to 0 may be set during the compensation control. Instead of the driving force command value TP, the determination can be made using the required driving force, the power running torque of the second motor generator MG2 controlled according to the driving force command value TP, or the like. Equation (2) determines that whether the vehicle speed is lower than a vehicle speed upper threshold SPDmax1 determined in advance through experiments or the like, because when the vehicle speed spd increases, abnormal noise such as rattling noise is not bothered by running noise. . If the determination in S3 is YES (affirmative), that is, if both the expressions (1) and (2) are satisfied, the process proceeds to S7, and the execution of the intermittent control for stopping the engine 12 is prohibited. Thereby, the engine 12 is maintained in an operating state such as an idle state. The basic restriction unit 86 that executes S3 corresponds to a second rotation stop restriction unit, the expression (1) corresponds to a second restriction range regarding the driving force, and the vehicle speed upper threshold SPDmax1 in the expression (2) corresponds to the second rotation stop restriction unit. This corresponds to an upper limit determination value of 2.
TPmin <TP <TPmax (1)
spd <SPDmax1 (2)

If the determination in S3 is NO (negative), that is, if at least one of the equations (1) and (2) is not satisfied, the steps from S4 are executed. S4 to S6 are conditions for judging prohibition of intermittent engine during high resistance. That is, at the time of high resistance, even if the driving force command value TP is equal to or greater than the driving force upper limit determination threshold TPmax and the determination in S3 is NO, the vehicle may run at a relatively low vehicle speed, and the engine intermittent control process may be performed. When the driving force suddenly decreases due to the accelerator returning operation, the torque of the second motor generator MG2 decreases to 0 or less as shown in FIG. 3, and rattling noises and the like may be generated, which may cause the driver to feel uncomfortable. There is. S4 to S6 are for prohibiting the engine intermittent control under a certain condition at the time of such a high resistance. In S4, it is determined whether the running resistance satisfies a predetermined high resistance determination condition that is large. Determines whether at least one of the following equation (3) relating to the road surface gradient Φ and the following equation (4) relating to the estimated vehicle weight Wguess is satisfied. Equation (3) determines whether the road surface gradient Φ is large and is greater than a gradient lower limit threshold Φmin predetermined by experiments or the like. Although the road surface gradient Φ is detected by the inclination sensor 70, it can be calculated from the driving force command value TP, the output rotation speed Nout, and the like. Equation (4) is for a case where the estimated vehicle weight Wguess is large. In the present embodiment, it is determined whether or not the towed vehicle weight Wtowing when the towed vehicle is connected is larger than the towed vehicle weight Wtowing. The estimated vehicle weight Wguess can be calculated from, for example, the road surface gradient Φ, the driving force command value TP, the output rotation speed Nout, and the like. Instead of the estimated vehicle weight Wguess, whether or not the running resistance is large may be determined based on an ON / OFF signal of a towing switch that is switched ON / OFF depending on the presence or absence of a towing vehicle. If neither of the equations (3) and (4) is satisfied, that is, if the running resistance is relatively small, S8 is executed to permit the execution of the engine intermittent control, but the equations (3) and (4) If at least one of the expressions is satisfied, S5 is executed.
Φ> Φmin ・ ・ ・ (3)
Wguess> Wtowing ・ ・ ・ (4)

In S5, it is determined whether or not the vehicle is traveling at a predetermined low speed according to the following equation (5). Equation (5) determines whether the vehicle speed spd is lower than a predetermined vehicle speed upper threshold SPDmax2. The vehicle speed upper threshold SPDmax2 may be the same as the vehicle speed upper threshold SPDmax1 of S3, Is large, the change (decrease) in the vehicle speed at the time of the accelerator return operation is large. Therefore, it is desirable to set a value larger than the vehicle speed upper threshold SPDmax1. If the equation (5) is not satisfied, that is, if the vehicle speed spd is relatively high, even if a rattling noise or the like occurs when the engine stops rotating, the noise is canceled by the running noise and the occupant does not feel uncomfortable. , S8 are executed to permit the execution of the engine intermittent control, but if the equation (5) is satisfied, S6 is executed.
spd <SPDmax2 (5)

  In S6, when the execution of the engine intermittent control is permitted and the rotation stop control is performed, it is determined whether or not the intermittent prohibition condition regarding the estimated driving force TPSTP when the rotation stop control is executed is satisfied. That is, as shown in FIG. 3, when the engine intermittent determination is made at time t1, even if the execution of the engine intermittent control is permitted as it is, the engine speed Ne is reduced by the torque control of the first motor generator MG1. The rotation stop control for stopping is performed after performing preparations such as stopping the operation of the engine 12 by fuel cut or the like, or performing a drive source transfer process of switching the driving force by the engine 12 to the torque of the second motor generator MG2, The driving force TPSTP after a predetermined preparation time tprep (time t1 to t2 in FIG. 3) required for the preparation is estimated. Specifically, the estimated driving force TPSTP is calculated by adding the estimated driving force change amount ΔTP to the current driving force command value TP. The estimated driving force change amount ΔTP can be calculated from, for example, the change rate of the driving force command value TP, the required driving force, the preparation time tprep, and the like. The pre-preparation time tprep may be a constant value, but may be variably set using the throttle valve opening, engine torque, and the like as parameters. In addition, since the driving force may decrease during the execution of the rotation stop control, the driving force when the torque of the second motor generator MG2 is decreased by the compensation control may be estimated.

The intermittent prohibition condition regarding the estimated driving force TPSTP in S6 determines whether the estimated driving force TPSTP is within a predetermined limit range according to the following equation (6). That is, the power running torque of the second motor generator MG2 controlled in accordance with the driving force command value TP is within a range in which the compensating control during the rotation stop control may drop to around 0 or less as shown in FIG. It is determined whether or not. The estimated driving force lower limit determination threshold value TPSTPmin and the estimated driving force upper limit determination threshold value TPSTPmax are determined in advance by experiments or the like in the same manner as the driving force lower limit determination threshold value TPmin and the driving force upper limit determination threshold value TPmax. , The same value as the driving force upper limit determination threshold value TPmax. The estimated driving force lower limit determination threshold value TPSTPmin and the estimated driving force upper limit determination threshold value TPSTPmax shown in FIG. 3 are values converted into the torque of the second motor generator MG2, and when the MG2 torque is predicted to change as indicated by the solid line. , S6, the intermittent prohibition condition is satisfied. If the equation (6) is satisfied, the garbled sound, rattling noise, and the like may be generated due to the decrease in the torque of the second motor generator MG2 during the compensation control. Therefore, the execution of the engine intermittent control is prohibited in S7. If the equation (6) does not hold, S8 is executed to permit execution of the engine intermittent control. The driving force determination in S3 can also be performed using the estimated driving force TPSTP.
TPSTPmin <TPSTP <TPSTPmax (6)

  According to such a hybrid vehicle 10, when the running resistance is large (the determination in S4 is YES), the driving force TPSTP when the rotation stop control of the engine 12 is executed is estimated, and the estimated driving force TPSTP is calculated. When Expression (6) is satisfied within the predetermined limit range (YES in S6), execution of the engine intermittent control is prohibited (S7). For this reason, when the driving force suddenly decreases due to the operation of returning the accelerator or the like, and the torque of the second motor generator MG2 decreases to around 0 or less due to compensation during the rotation stop control of the engine 12, the engine 12 Before the intermittent control is executed, the intermittent control is prohibited, and generation of abnormal noise such as rattling noise can be appropriately suppressed. Further, since the execution of the intermittent engine control is prohibited based on the estimated driving force TPSTP, the fuel consumption performance is appropriately secured as compared with the case where the intermittent operation of the engine 12 is uniformly prohibited when the running resistance is large.

  Further, in this embodiment, when the vehicle speed spd is equal to or greater than the predetermined vehicle speed upper threshold SPDmax2 (NO in S5), the execution of the engine intermittent control is permitted in S8. The intermittent operation is not prohibited until such a situation as to cancel the occupant does not cause a sense of incongruity. In this respect, the fuel consumption performance is appropriately secured. Note that S5 is omitted, and S6 is always executed when the running resistance is large. When the estimated driving force TPSTP is within a predetermined limit range (YES in S6), execution of the engine intermittent control is prohibited. You may do it.

Next, another embodiment of the present invention will be described.
FIG. 4 is a flowchart executed by the intermittent operation limiting unit 84 instead of FIG. 2, and the estimated driving force TPSTP is determined in two stages as compared with the flowchart of FIG. S6-1 and S6-2 are provided in place of, and S9 is executed when the determination in S6-2 is YES. S4, S5, S6-1, S6-2, S7, and S9 correspond to the high-resistance limiter 88 that functions as the rotation stop limiter of the present invention.

In S6-1 of FIG. 4, as shown in the following equation (7), the intermittent operation in which the estimated driving force TPSTP is larger than the first determination threshold value TPSTP1 and is within a relatively low driving force range equal to or less than the second determination threshold value TPSTP2. It is determined whether or not the prohibition condition is satisfied. If Expression (7) is satisfied, S7 is executed to prohibit execution of the engine intermittent control. If the equation (7) does not hold and the determination in S6-1 is NO, S6-2 is executed, and the estimated driving force TPSTP is larger than the second determination threshold TPSTP2 as shown in the following equation (8). Then, it is determined whether or not an intermittent restriction condition that falls within a relatively high driving force range smaller than the third determination threshold value TPSTP3 is satisfied. If the determination in S6-2 is YES, that is, if equation (8) is satisfied, step S9 is executed, and if equation (8) is not satisfied, step S8 is executed. The first determination threshold TPSTP1 is, for example, the same as the estimated driving force lower limit determination threshold TPSTPmin, the third determination threshold TPSTP3 is, for example, the same as the estimated driving force upper determination threshold TPSTPmax, and the second determination threshold TPSTP2 is, for example, the first determination threshold. This is an intermediate value between TPSTP1 and the third determination threshold value TPSTP3.
TPSTP1 <TPSTP ≦ TPSTP2 (7)
TPSTP2 <TPSTP <TPSTP3 (8)

  In S9, the torque of the first motor generator MG1 when the engine rotation speed Ne is forcibly reduced during the rotation stop control of the engine 12 is reduced, and execution of the engine intermittent control is permitted. That is, when the MG1 torque at the time of lowering the engine rotation speed Ne is reduced, the increase in the rotation torque of the output gear 30 due to the reaction force due to the inertia of the engine 12 is suppressed, and the second motor generator for compensating the increase in the torque. The decrease in the powering torque of the MG2 is reduced, and the reduction of the MG2 torque to around 0 or less is suppressed. The MG2 torque indicated by the solid line in FIG. 5 is an example of a time chart in the case where the reduction torque is reduced in S9, and the chain line is the MG2 torque during the normal rotation stop control, and the decrease amount of the MG2 torque decreases. Is reduced to around 0 or less, and generation of abnormal noise such as rattling noise is suppressed. If the reduction torque of the engine rotation speed Ne by the first motor generator MG1 is reduced, the reduction speed of the engine rotation speed Ne slows down and it takes time, and there is a possibility that abnormal noise due to resonance or the like may occur. MG1 torque is determined so that no abnormal noise is generated, and second determination threshold value TPSTP2 is determined based on the decrease amount of MG2 torque for suppressing a change in driving force due to the MG1 torque. The first determination threshold TPSTP1, the second determination threshold TPSTP2, and the third determination threshold TPSTP3 shown in FIG. 5 are values converted into the torque of the second motor generator MG2.

  In the present embodiment, the range of the estimated driving force TPSTP for prohibiting the execution of the engine intermittent control is reduced to the second determination threshold value TPSTP2 or less while appropriately suppressing generation of abnormal noise such as rattling noise. In the range larger than the second determination threshold value TPSTP2, the engine intermittent control is performed, and the fuel efficiency is improved.

  As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, these are merely examples, and the present invention is implemented in various modified and improved forms based on the knowledge of those skilled in the art. be able to.

  10: Hybrid vehicle 12: Engine 22: Power split mechanism (power split section) 30: Output gear (output member) 34: Speed change gear mechanism (meshing mechanism) 40: Drive wheel 80: Electronic control device 82: Hybrid control section ( Engine stop control unit) 84: Intermittent operation limit unit (engine stop control unit) 88: High resistance limit unit (rotation stop limit unit) MG1: First motor generator (first rotating machine) MG2: Second motor generator (No. TPSTP: Estimated driving force

Claims (1)

A power splitting unit that splits the power transmitted from the engine into a first rotating machine and an output member, and outputs the power to the drive wheels from the output member;
A second rotating machine that outputs power to the driving wheel or another driving wheel via a mechanical meshing mechanism,
A hybrid vehicle having
During running of the vehicle, the torque of the first rotating machine is reduced by a torque control of the first rotating machine to stop the rotation of the engine after a predetermined preparation, and the driving force fluctuation caused by the torque control is reduced by the second rotating machine. In the engine stop control device that performs the rotation stop control that is compensated by
When the running resistance satisfies a predetermined high resistance determination condition, the pre-preparation is performed based on a change rate of the driving force command value or the driving force request value and a predetermined pre-preparation time required for the pre- preparation. of the rotating driving force when the rolling stop control is executed estimated after, when the estimated estimated driving force is a driving force is within a predetermined limited range greater than 0, the rotation stop control An engine stop control device for a hybrid vehicle, comprising: a rotation stop limiting unit that limits the rotation.

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