JP2006341848A - Controller for hybrid vehicle with transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve fuel consumption, emission, and drivability by selecting a suitable gear stage in a hybrid vehicle with a transmission. <P>SOLUTION: The priority of driving force adjustment control to a request of a vehicle driving force is set in the order of engine power increase, motor output increase, and gear ratio increase. To be more specific, a gear stage with the smallest gear ratio is selected in a range in which engine speed more than a predetermined minimum speed is achieved S12, S14, a requested driving force is attained with an engine power at the selected gear stage S16, the requested driving force is attained with the engine output and the motor output when the requested driving force cannot be attained only with the engine power S18, and gear stage is changed such that the gear ratio increases when the requested driving force cannot be attained with the engine power and the motor output S20. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for a hybrid vehicle with a transmission having an engine, a motor, and a transmission, and more particularly to improvements in fuel efficiency, emission, power performance, and the like.

  As is well known, a hybrid vehicle has an engine and a motor as a driving force source. The motor is preferably used not only for generating vehicle driving torque but also as a generator. From this point of view, the motor is also called a motor generator. In the hybrid vehicle, the fuel efficiency can be improved by efficiently operating the engine and the motor.

  Currently, a mechanical distribution type hybrid vehicle has been put into practical use, and an engine and two motors are connected to a planetary gear unit. This type is not provided with a transmission. On the other hand, a hybrid vehicle in which an engine, a motor, and a transmission are connected has been proposed, and is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-168104. In addition to the conventional stepped transmission (a type that selects a plurality of gear stages), a system in which a continuously variable transmission is mounted has also been proposed.

  The above-described mechanically distributed hybrid device is optimized from the viewpoint of fuel consumption and the like by controlling the operating states of the engine and the motor. However, this type is not provided with a transmission for selecting a gear stage.

  Next, considering a conventional vehicle that is not a hybrid vehicle, the shift characteristic (shift line) of the automatic transmission is set to correspond to the vehicle speed and the accelerator opening. Based on this speed change characteristic, the gear stage of the transmission is determined. In a so-called MMT (multi-mode manual transmission: a transmission in which the clutch pedal is eliminated and the clutch engagement / disengagement operation is automatically performed by an actuator), the gear stage is similarly determined using the shift line.

  When a motor for assist torque is further added to the system in which the engine and the transmission are connected, the hybrid vehicle with the transmission is configured. In a hybrid vehicle with a transmission, it is not possible to select the gear stage that allows the most efficient driving if the shift line for only the conventional engine is applied as it is despite the addition of a motor, and the efficiency, It is difficult to properly control emissions and power performance.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a control device capable of appropriately controlling a hybrid vehicle having a transmission in terms of efficiency, emission, power performance, and the like. is there.

  (1) In order to achieve the above object, the present invention provides a transmission having an engine and a motor as a vehicle driving force source, and capable of changing driving force transmission by selecting a plurality of gear stages between the engine and driving wheels. In the control device for a hybrid vehicle with a transmission, the priority of driving force adjustment control with respect to the request for vehicle driving force is set in the order of engine output increase, motor output increase, and gear ratio change in the direction of gear ratio increase. It is characterized by that.

  For example, the control device of the present invention selects (i) a gear stage having the smallest gear ratio within a range where an engine speed equal to or higher than a predetermined lower limit speed is obtained, and (ii) outputs engine power at the selected gear stage. (Iii) If the required driving force cannot be achieved by engine output alone, the required driving force can be achieved by engine output and motor output. (Iv) The required driving force can be achieved by engine output and motor output. If it cannot be achieved, the gear stage is changed in the direction of increasing the gear ratio.

  According to the present invention, the required driving force is achieved by adjusting the engine output, the motor output, and the gear stage in this order. The priority for changing the gear position is low, and the priority for changing the engine output is high. Therefore, when a driving force request is generated, the engine output is increased by setting the gear stage low. As a result, fuel efficiency is improved because the engine is efficiently operated at low speed and high load. Furthermore, if the priority order is set as described above, the number of shift changes is reduced, so that frequent downshifts are eliminated, drivability is improved, and emission is improved.

  Preferably, the control device of the present invention further changes the gear stage according to a factor that affects motor control. Factors that affect motor control include, for example, SOC (battery charge state), battery temperature, or inverter temperature. According to this aspect, it is possible to secure a stable output supply capability on the motor side, and to prevent a decrease in power performance.

  (2) Another aspect of the present invention is a shift having an engine and a motor as a vehicle driving force source, and further including a transmission capable of changing driving force transmission by selecting a plurality of gear stages between the engine and driving wheels. In the control device for a hybrid vehicle with a machine, the gear stage of the transmission is operated so that the engine is operated in a predetermined high-efficiency operation state, and the difference between the requested vehicle driving force and the engine output is filled by powering or regeneration of the motor. The engine operating state is set. Preferably, while operating the engine in a predetermined high-efficiency driving state, the gear stage with the smallest gear ratio is set to the transmission within a range in which the difference between the required vehicle driving force and the engine output is filled by powering or regeneration of the motor. Set.

  According to the present invention, since the engine is operated with high efficiency by selecting an appropriate gear stage, fuel efficiency can be improved. The engine is preferably operated at the maximum efficiency point. Further, by selecting a gear stage having a small gear ratio, as described above, fuel efficiency, emission, and drivability can be improved.

  Preferably, the predetermined high-efficiency operation state is a state where the product of the engine efficiency and the transmission transmission efficiency is maximized. According to this aspect, the gear ratio and the engine operating state are set so that the highest efficiency operation including the transmission system is possible, and the fuel efficiency can be improved.

  Preferably, the transmission gear stage and the engine operating state are further set such that the engine is operated in a predetermined good emission region. This can improve emissions.

  (3) Another aspect of the present invention is a shift that includes an engine and a motor as a vehicle driving force source, and further includes a transmission that can change driving force transmission by selecting a plurality of gear stages between the engine and driving wheels. In the control apparatus for a hybrid vehicle with a machine, when the driving force required for the vehicle is negative, the gear stage of the transmission is set so that the efficiency of regenerative braking by the motor is maximized.

  In a hybrid vehicle with a transmission, the efficiency of motor regenerative braking changes according to the gear stage of the transmission. For example, in a state where the engine is driven by the motor, the rotational resistance force on the engine side is reduced and the regenerative braking efficiency on the motor side is increased when the gear ratio is reduced. Focusing on this point, the present invention selects the gear stage that maximizes the efficiency of regenerative braking, so that it is possible to improve fuel consumption and emissions.

  In the present invention, preferably, a different gear stage is selected depending on whether or not the engine rotation is stopped during the motor regenerative operation. This aspect assumes a configuration in which engine rotation can be stopped by means such as a clutch. If the engine is rotating, as described above, the smaller the gear ratio, the smaller the rotational resistance on the engine side and the higher the regenerative braking efficiency on the motor side. If the engine is not rotating, it is not necessary to consider the rotational resistance force on the engine side, so a gear stage that increases the efficiency on the motor side is selected. In this way, by selecting different gear stages according to the presence or absence of engine rotation, fuel efficiency and emissions can be further improved.

  The aspect of the present invention is not limited to the hybrid vehicle control apparatus as described above. Another aspect of the present invention is, for example, a hybrid vehicle or a hybrid system, and a control method for the hybrid vehicle or the hybrid system.

  As described above, according to the present invention, in a hybrid vehicle with a transmission, an appropriate gear stage capable of efficiently operating an engine and a motor is selected to improve efficiency, emission, power performance, and the like. Can do.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments (hereinafter referred to as embodiments) of the invention will be described with reference to the drawings.

<1-1. >
FIG. 1 is a block diagram illustrating a configuration example of a direct-coupled hybrid vehicle with a transmission. The hybrid vehicle 1 has an engine 3 and a motor generator 5 as driving force sources. The engine 3 and the motor generator 5 are connected, an automatic transmission 7 is connected to the motor generator 5, and the automatic transmission 7 is connected to drive wheels (not shown). When the motor generator 5 functions as a motor, it receives power supply from the battery 9 and generates driving force. When the motor generator 5 functions as a generator, the motor generator 5 rotates with engine output to generate electric power, and sends electric power to the battery 9.

  Within the scope of the present invention, the motor generator 5 is not limited to the arrangement shown in FIG. 1 and may be provided, for example, on the drive wheel side of the automatic transmission 7. The motor generator 5 may be connected to an engine output shaft or the like, an input / output shaft of a transmission, or the like via a clutch.

  In place of the automatic transmission 7, a so-called MMT (multimode manual transmission) may be arranged. In the MMT, unlike the conventional manual transmission, the clutch pedal is abolished, and an actuator for automatically operating the clutch is provided instead of the driver. By the mode setting, the gear stage is automatically determined by the control device as in the case of the automatic transmission. As described above, the present invention is similarly applied to transmissions other than the automatic transmission as long as the transmission can select a plurality of gear stages.

  The engine 3, the motor generator 5, and the automatic transmission 7 are controlled by a hybrid ECU 11. The hybrid ECU 11 may be a single computer or a plurality of computers. For example, the engine control unit 13, the motor generator control unit 15, and the automatic transmission control unit 17 may be configured by three separate ECUs.

  The hybrid ECU 11 receives the accelerator operation amount of the driver from the accelerator sensor 21, the vehicle speed from the vehicle speed sensor 23, the engine speed from the engine rotation sensor 27, and a detection indicating the battery charge state from the battery sensor 25. A signal is input. The hybrid ECU 11 appropriately operates the engine 3, the motor generator 5, and the automatic transmission 7 based on the traveling state of the vehicle, the operation of the driver, and the state of charge of the battery using these input information.

  Here, it is assumed that the motor generator is not provided in the system of FIG. In this case, the same control as that of a conventional vehicle equipped with an automatic transmission that is not a hybrid may be performed. That is, a shift line (shift map) set according to the vehicle speed and the accelerator operation amount is stored, a gear stage is determined according to the shift line, and the transmission is controlled.

  In the case of this embodiment, a motor generator as a torque assist device is further added. Therefore, when the automatic transmission is controlled using the conventional shift map, high-efficiency driving as a hybrid vehicle is not performed. For example, it is assumed that a significant increase in vehicle driving force is required because the driver suddenly steps on the accelerator. At this time, in the configuration of FIG. 1, it is conceivable to increase the motor output or to perform a downshift. What kind of control should be performed properly determines whether the engine 3, the motor generator 5, and the automatic transmission 7 can be used properly. In the present embodiment, in consideration of such points, the hybrid ECU 11 performs the following control.

  Referring to FIG. 2, the hybrid ECU 11 reads the vehicle speed and the accelerator operation amount in S10, and in S12 and S14, selects the gear stage with the smallest gear ratio (for high speed) at which an engine speed equal to or higher than a predetermined value is obtained. select. The predetermined value (engine speed lower limit) is set to a low value within a range where the engine torque fluctuation does not adversely affect the vehicle behavior, vibration, and the like, and is about 1200 rpm, for example. Specifically, it is determined in S12 whether or not the engine speed is greater than or equal to a predetermined value. If S12 is NO, the gear stage is changed to the first stage low side (in the direction in which the gear ratio increases) in S14, and the process returns to S12. If S12 is YES, the process proceeds to S16. The gear set in S12 and S14 is referred to as “temporarily set gear”.

  In S16, it is determined whether or not the required driving force can be achieved only by the engine output. The required driving force is obtained based on the accelerator operation amount and the vehicle speed. Here, using the vehicle speed read in S10 and the temporarily set gear set in S12 and S14, the engine speed when the temporarily set gear is adopted is obtained. Then, an engine maximum torque Temax corresponding to the engine speed is obtained. Temax is a value converted on the drive shaft.

  In the present embodiment, the engine maximum torque Temax is set to a value that maximizes the energy efficiency of the engine. That is, as the engine torque is increased at a certain engine speed, the energy efficiency gradually increases and becomes maximum. As the engine torque is further increased, the energy efficiency decreases. Temax is set at this maximum point.

  In S16, the required driving force is compared with Temax. If Temax is equal to or greater than the required driving force, the required driving force can be achieved only by the engine output. Therefore, the process proceeds to S22 and the gear stage is determined. The gear stage selected in S12 and S14 is adopted as it is. Then, the hybrid ECU 11 causes the engine 3 to generate a required driving force.

  If S16 is NO (the required driving force cannot be achieved only by the engine output), it is determined in S18 whether the required driving force can be achieved by the engine output and the motor output. Here, the engine speed when the temporarily set gear stage is employed is obtained, and the motor maximum torque Tmmax corresponding to the engine speed is obtained. This Tmmax is also a value converted on the drive shaft.

  In S18, the required driving force is compared with Temax + Tmmax. If Temax + Tmmax is equal to or greater than the required driving force, the required driving force can be achieved by engine output and motor output. Therefore, the process proceeds to S22 and the gear stage is determined. The gear stage selected in S12 and S14 is adopted as it is. Then, the hybrid ECU 11 causes the engine 3 and the motor generator 5 to generate the required driving force. Here, the maximum torque Tmmax is generated in the engine 3 and the deficient driving force is generated in the motor generator 5.

  If S18 is NO (the required driving force cannot be achieved even if the engine output and the motor output are used together), the process proceeds to S20, and the gear stage is changed to the first stage low side (the side where the gear ratio increases). As a result, the temporary setting gear set in S12 and S14 is changed by one step. Then, the process proceeds to S16 and the same process is repeated.

  As described above, according to this embodiment, the priority order of the driving force adjustment control is determined in the order of the engine output, the motor output, and the gear stage, and the required driving force is achieved by the adjustment according to this priority order. . Specifically, first, a gear stage having a gear ratio as small as possible is temporarily set, and if the required driving force can be covered by the engine output at the temporarily set gear stage, the engine output is used. Further, when the driving force requirement is high, torque assist is performed by the motor, and when the driving force requirement is further high, the transmission is shifted to the low speed gear.

  By such control, the gear stage is set low and the engine torque is set high. In addition, the engine can be operated with high efficiency at as low a rotation and high load as possible, and fuel efficiency can be improved.

  Further, until the motor torque reaches the maximum, the required driving force is achieved with the motor torque assist without downshifting. As a result, frequent downshifts do not occur, and drivability can be improved. In addition, if the number of downshifts is small, it is possible to reduce the influence (problem of AF controllability) of the sudden change in engine speed due to the downshift and to improve the emission.

<1-2. >
Next, a more preferable control process of the hybrid ECU 11 in the present embodiment will be described. Here, the hybrid ECU 11 changes the gear position based on a factor affecting the motor control, particularly a factor affecting the torque assist amount by the motor generator 5.

  Factors that affect the torque assist amount are, for example, SOC (battery charge state), battery temperature, inverter temperature, or the like. In the present embodiment, attention is paid to the fact that the torque that can be supplied from the motor side increases and decreases depending on the values of these parameters, and the gear stage on the transmission side is set in consideration of this increase and decrease.

  FIG. 3 shows an example of the control process of the present embodiment. Here, SOC is used as a factor that affects the torque assist amount. In FIG. 3, in addition to the control process of FIG. 2, S19 is provided after S18. In S19, the SOC of the battery is obtained. The SOC is represented, for example, by the ratio of the current charged amount to the charged amount in the fully charged state. The SOC is obtained using the battery voltage and current, and it is preferable to appropriately use the battery temperature. The SOC obtained by a separate battery ECU or the like may be input to the hybrid ECU.

  In S19, the current SOC is compared with a predetermined value. If the SOC is equal to or less than the predetermined value, the process proceeds to S20 and the gear stage is changed to the first stage low side. If the SOC exceeds the predetermined value in S19, the process proceeds to S22 and the gear stage is determined.

  Thus, in the present embodiment, the gear stage is set based on factors that affect the torque assist amount and torque assist capability of the motor generator 5. Thereby, the stable supply capability of assist torque is ensured, and the fall of power performance by torque shortage can be prevented. Furthermore, deterioration of the battery or the like can be prevented.

<2-1. >
Next, another embodiment of the present invention will be described. In the present embodiment, the configuration of the hybrid vehicle and its control device may be the same as in the first embodiment described above. In the present embodiment, control processing by the hybrid ECU 11 is improved, and further efficiency and fuel consumption can be improved.

  In the present embodiment, the hybrid ECU 11 selects the gear stage having the smallest gear ratio (the gear stage on the high speed side) within the range where the required driving force can be achieved by the engine output and the motor output at the current vehicle speed. Then, the engine is operated in a predetermined high efficiency operation state at the selected gear stage. The difference between the engine output and the required driving force is covered by the power running or regenerative operation of the motor.

  FIG. 4 shows a specific example of the control processing of the present embodiment, in which the horizontal axis is the axle rotation speed Np, and the vertical axis is the axle torque Tp. In the figure, a low gear required driving force attainable area AL and a high gear required driving force attainable area AH are shown.

  In the region AL, the center line L is the engine torque when the engine is operated at the highest efficiency when the low gear is set (converted to the axle torque, the same applies hereinafter). The upper limit line LU is above the line L by the maximum value of the motor power running torque. The lower limit line LB is lower than the line L by the maximum value of the motor regeneration torque. In the present embodiment, this area AL is defined as a range in which the required driving force can be achieved with low gear. The high gear required driving force attainable area AH is set similarly to the low gear area AL. However, the shape and position of the region differ depending on the difference in gear ratio.

  In the example of FIG. 4, the hybrid ECU 11 controls the transmission, the engine, and the motor as follows. As described above, the hybrid ECU 11 first selects the gear stage having the smallest gear ratio within a range where the required driving force can be achieved with the engine output (maximum efficiency operation) and the motor output at the current vehicle speed.

  For example, it is assumed that the combination of the required driving force and the axle rotation speed (vehicle speed) is a point Pa in FIG. In this case, the point Pa is included only in the high gear required driving force attainable region AH. Accordingly, the high gear is selected.

  Further, it is assumed that the combination of the required driving force and the axle rotational speed is a point Pc in FIG. In this case, the point Pc belongs to both the areas AL and AH, and either gear can be selected. Therefore, the hybrid ECU 11 selects a gear stage having a smaller gear ratio, that is, a high gear.

  The above gear stage selection process can be expressed using the following equation.

(Equation 1)
Temax (i, v) -Tm regeneration max (i, v)
≤ Required driving force ≤ Temax (i, v) + Tm power running max (i, v)
Temax (i) is torque (converted to axle torque, the same applies hereinafter) in the engine maximum efficiency operating state at the gear stage i and the vehicle speed v. Tm regeneration max (i, v) and Tm power running max (i, v) are also the maximum values of the regenerative torque and power running torque at gear stage i and vehicle speed v (however, the motor is provided on the wheel side of the transmission). If so, the motor torque is not affected by the gear ratio). In the present embodiment, the gear stage i having the smallest gear ratio that satisfies the above equation is selected.

  The gear selection process flow may be substantially the same as in FIG. That is, first, based on the vehicle speed, a gear stage having the smallest gear ratio that can obtain an engine speed equal to or higher than a predetermined lower limit speed is temporarily set. If the above equation is satisfied at the temporarily set gear stage, the gear stage is adopted as it is. If the above equation is not satisfied, the gear stage is changed to the first stage low side. This process is continued until the above equation is satisfied. As a result, the highest gear that can satisfy the required driving force is selected.

  In the example of FIG. 4, the number of gear stages is two, but the same gear stage selection process may be performed for transmissions with three or more stages.

  Next, engine control and motor control at the selected gear stage will be described. In the present embodiment, as described above, the engine is operated in the high-efficiency operation state, and the difference between the engine output and the required driving force is covered by the power running or regenerative operation of the motor.

  Specifically, in the example of FIG. 4, it is assumed that the combination of the required driving force and the axle rotation speed is a point Pa. In this case, the engine is operated at a point Pb on the line H. As described above, the line H indicates the output torque in the engine maximum efficiency operation state when the high gear is set. Since the engine output exceeds the required driving force, the difference between the two is absorbed by the motor regenerative operation. The electric power obtained by regeneration is stored in the battery.

  On the other hand, it is assumed that the combination of the required driving force and the axle rotation speed is a point Pc in FIG. In this case, the engine is operated at a point Pd on the line H. Since the engine output does not reach the required driving force, the shortage is compensated by motor power running. At this time, power is taken out from the battery.

  As described above, in this embodiment, the engine operating range and the gear stage are selected so that the engine efficiency is maximized by the regeneration and power running of the motor generator, so that the engine can be operated with high efficiency. Can improve fuel efficiency.

<2-2. >
A modification of the above embodiment will be described. In the above embodiment, the engine operating range and the gear stage are selected so that the engine is operated at the highest efficiency. In this modification, the engine operating range and gear stage are selected so that the product of the engine efficiency and the transmission transmission rate is maximized.

  In the example of FIG. 4, the line H that defines the output torque in the maximum efficiency operation state of the engine is used. Instead of this line H, a line that maximizes “engine efficiency × transmission transmission efficiency” is used. The transmission transmission efficiency is determined according to the gear stage and the axle rotation speed.

  According to the present embodiment, not only the engine but also the transmission system can be operated at the highest efficiency, and the fuel consumption can be further improved.

<2-3. >
Another modification of this embodiment will be described. In this modification, the engine operating range and the gear stage are selected so that the emission is further optimized in the above control. That is, in consideration of the fact that the emission varies depending on the engine operating range, an operating range in which the emission is good is selected.

  In the specific example of FIG. 5, it is assumed that the engine of the hybrid vehicle is a diesel engine. As shown in FIG. 5, in the case of a diesel engine, there is an emission deterioration region where EGR does not enter at a low rotation and high load. Therefore, avoid this area and select the engine operating range and gear stage.

  For example, it is assumed that the combination of the axle rotation speed and the required driving force is a point Pe in FIG. If the engine is operated at the maximum efficiency point (on line H), the operating point enters the emission deterioration region. In order to avoid this, the point Pg in the figure is selected as the operating range. In this case, since the engine output is insufficient with respect to the required driving force, the shortage is supplemented by the motor output (power running).

  As described above, in this embodiment, since the transmission gear stage and the engine operating state are set so as to avoid the emission deterioration region, that is, the engine is operated in the emission good region, the emission can be improved. .

<3-1. >
So far, the control in the case where the required driving force is positive has been mainly described. Here, a suitable control when the required driving force is negative will be described.

  When the required driving force is negative, regenerative braking is basically performed by the motor generator, and the obtained electric power is charged in the battery. Here, the present invention is directed to a hybrid vehicle with a transmission, and there is a problem of how to control the transmission during regenerative braking. In the present invention, when the required driving force is negative, the gear stage is set on the transmission side so that the efficiency of regenerative braking on the motor side is maximized.

  For example, consider a hybrid vehicle having the configuration shown in FIG. A transmission is connected to the engine, and a motor generator is connected between the transmission and the wheels. It is assumed that the motor generator is directly connected to the output shaft of the transmission.

  In this case, the engine is driven by the motor during regenerative braking. Engine friction (rotational resistance) is a factor that reduces regenerative braking efficiency. Therefore, the control device for the hybrid vehicle selects the gear stage having the smallest gear ratio (the highest gear stage) during regenerative braking, and causes the transmission to perform a shift change to that gear stage.

  This control reduces the gear ratio, minimizes the friction loss given from the engine to the motor generator via the transmission, and increases the efficiency of regenerative braking.

  As described above, according to the present embodiment, when the required driving force is negative, the gear stage having the highest regeneration efficiency is selected by the transmission, so that it is possible to improve fuel consumption and emission.

<3-2. >
Next, a second example of transmission control when the required driving force is negative will be described. Here, a hybrid vehicle configured to be able to stop engine rotation is assumed. In this embodiment, when selecting the gear stage having the maximum regeneration efficiency, an optimum gear stage that is different depending on whether or not the engine rotation is stopped is set.

  This embodiment is applied, for example, to the hybrid vehicle control device of FIG. The motor generator is disposed between the engine and the transmission. The rotating shaft of the motor generator is connected to the input shaft of the transmission. A clutch is interposed between the motor rotation shaft and the engine rotation shaft.

  When the required driving force is negative, the control device determines whether the engine is rotating or stopped. If the clutch is connected, the engine is rotating in the fuel cut state. On the other hand, if the clutch is disengaged, the engine is stopped.

  The control device selects the gear stage having the smallest gear ratio when the engine is rotating. As a result, the transmission amount of the engine rotation resistance force is reduced, and the efficiency of regenerative braking is increased. On the other hand, when the engine is stopped, the gear stage at which the efficiency of the motor generator is maximized is selected. When the engine is stopped, it is not affected by the engine rotation resistance, so that the regenerative braking efficiency is maximized by this gear selection. The control device performs shift change control to the gear stage selected in this way. In addition, the motor generator is caused to perform regenerative braking.

  As described above, according to the present embodiment, by setting the gear stage differently depending on whether the engine is rotated or stopped, the efficiency of regenerative braking can be increased in both modes, and fuel efficiency and emission can be improved.

1 is a block diagram showing an overall configuration of a hybrid vehicle in an embodiment of the present invention. It is a flowchart which shows the control processing by hybrid ECU of FIG. 6 is a flowchart showing a second example of control processing by the hybrid ECU of FIG. 1. It is a figure which shows the control processing of the hybrid vehicle in another embodiment of this invention. It is a figure which shows the modification of the control processing of FIG. It is a figure which shows an example of a hybrid vehicle for demonstrating the control processing when the request | requirement driving force with respect to a vehicle is negative. It is a figure which shows an example of a hybrid vehicle for demonstrating another example of the control processing when the request | requirement driving force with respect to a vehicle is negative.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Hybrid vehicle, 3 engine, 5 motor generator, 7 automatic transmission, 11 hybrid ECU, 13 engine control part, 15 motor generator control part, 17 transmission control part, 21 accelerator sensor, 23 vehicle speed sensor, 25 battery sensor, 27 Engine rotation sensor.

Claims (9)

In a control apparatus for a hybrid vehicle with a transmission, which has an engine and a motor as a vehicle driving force source, and further has a transmission capable of changing driving force transmission by selecting a plurality of gear stages between the engine and driving wheels.
A control device for a hybrid vehicle, wherein the priority of driving force adjustment control with respect to a request for vehicle driving force is set in the order of engine output increase, motor output increase, and gear stage change in a gear ratio increasing direction. In the hybrid vehicle control device according to claim 1,
Select the gear stage with the smallest gear ratio in the range where the engine speed equal to or higher than the predetermined lower speed can be obtained,
Achieving the required driving force with the engine output at the selected gear stage,
If the required driving force cannot be achieved by engine output alone, the required driving force is achieved by engine output and motor output.
A control apparatus for a hybrid vehicle, characterized in that when the required driving force cannot be achieved by engine output and motor output, the gear stage is changed in a direction to increase the gear ratio. In the hybrid vehicle control device according to claim 1 or 2,
Furthermore, the control apparatus of the hybrid vehicle characterized by changing a gear stage according to the factor which affects motor control. In a control apparatus for a hybrid vehicle with a transmission, which has an engine and a motor as a vehicle driving force source, and further has a transmission capable of changing driving force transmission by selecting a plurality of gear stages between the engine and driving wheels.
The gear stage of the transmission and the engine operating state are set so that the engine is operated in a predetermined high-efficiency driving state and the difference between the required vehicle driving force and the engine output is filled by powering or regeneration of the motor. A control device for a hybrid vehicle. The hybrid vehicle control device according to claim 4,
Set the gear stage with the smallest gear ratio for the transmission within the range where the difference between the required vehicle driving force and the engine output can be filled by the power running or regeneration of the motor while the engine is operated in a predetermined high efficiency operation state. A hybrid vehicle control device. In the hybrid vehicle control device according to claim 4 or 5,
The control apparatus for a hybrid vehicle, wherein the predetermined high-efficiency driving state is a state in which a product of engine efficiency and transmission transmission efficiency is maximized. In the hybrid vehicle control device according to claim 4,
Furthermore, a control apparatus for a hybrid vehicle, wherein a transmission gear stage and an engine operating state are set so that the engine is operated in a predetermined good emission region. In a control apparatus for a hybrid vehicle with a transmission, which has an engine and a motor as a vehicle driving force source, and further has a transmission capable of changing driving force transmission by selecting a plurality of gear stages between the engine and driving wheels.
A control apparatus for a hybrid vehicle, wherein a gear stage of a transmission is set so that the efficiency of regenerative braking by a motor is maximized when a driving force required for the vehicle is negative. In the hybrid vehicle control device according to claim 8,
A control apparatus for a hybrid vehicle, wherein different gear stages are selected depending on whether or not engine rotation is stopped during motor regenerative operation.

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