JP4292635B2 - Vehicle drive system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention is a vehicle.DriveThe present invention relates to a system, and more particularly to a drive system that can obtain a smooth start performance.
[0002]
[Prior art]
  As a driving force source for movement for moving a moving body, a driving system for a moving body having a first driving force source and a second driving force source having a rated output smaller than that of the first driving force source is known. ing. An example of this is a hybrid vehicle drive system equipped with an engine that operates by fuel combustion and an electric motor that operates by electric energy as a driving force source for vehicle travel. In general, an engine is more rated than an electric motor. The output is large. The device described in Japanese Patent Laid-Open No. 10-136508 is one example, and a sub-transmission comprising a simple planetary planetary gear device is provided, and only an electric motor is used as a driving force source depending on the engagement state of two clutches. Various driving modes are established such as a motor driving mode for driving and an engine driving mode using only the engine as a driving force source. In such a vehicle drive system, the engine is generally stopped when the vehicle is stopped, and the engine is started in the motor travel mode, and then the engine is started and switched to the engine travel mode. .
  “Rated output” is the maximum output that can be used continuously. For example, in the case of an electric motor, “When the motor is continuously operated at the rated speed, it reaches a certain value within a range where the temperature rise does not exceed the limit. The rated output speed is “the rotational speed of the motor that operates at the rated output. The rotational speed that does not interfere with acceleration / deceleration at the maximum torque”.
[0003]
[Problems to be solved by the invention]
  However, when starting the engine after starting in the motor running mode and shifting to the engine running mode as described above, if the engine starts slowly or cannot be started, a feeling of rattling may occur even if the driving force is insufficient. There is. If a large-capacity electric motor that can produce a large output is installed as a driving force source for driving, the lack of driving force can be reduced by operating the electric motor to a higher output than usual when the engine cannot be started. Or, although it can be eliminated, it becomes an excessive quality that is not necessary during normal traveling, resulting in an increase in cost and a large installation space.
[0004]
  The present invention has been made against the background of the above circumstances, and its object is to provide an electric motor.AndThe engine with a large rated output while adopting a small and inexpensive one with a small rated outputNIt is to improve the driving force shortage due to the delay in starting operation and the inability to operate.
[0005]
[Means for Solving the Problems]
  In order to achieve this object, the present invention provides a hybrid vehicle having an engine that operates by combustion of fuel and an electric motor that operates by electric energy as a driving power source for driving the vehicle. In the drive system, (a)When the vehicle is stopped and when the brake is fully depressed, the foot brake pedal stroke is larger than the predetermined BS2, the outputs of the engine and the electric motor are both set to 0 and the vehicle is kept stopped. (B) While holding the vehicle at 100% hold force,At predetermined low speed drivingIn addition, when the brake in the area of BS1 to BS2 where the pedal stroke of the foot brake is smaller than when the brake is fully depressed, the hill hold force is reduced than when the brake is fully depressed.Low-speed motor traveling means that travels using only the electric motor as a driving force source;(c)At the predetermined low speed runningThe pedal stroke of the foot brake is smaller than when the brake is depressed slightly.When the brake is offAnd canceling the hill hold force completelyLow-speed engine traveling means for traveling using the engine as a driving force source;(d)When traveling at a higher speed than the predetermined low speed travelingAnd canceling the hill hold force completelyHigh-speed engine traveling means that travels using the engine as a driving force source.
[0007]
【The invention's effect】
  According to the vehicle drive system of the present invention, even when the vehicle is traveling at a predetermined low speed, when the brake is OFF, the low-speed engine traveling means travels using the engine as a driving force source and travels at a higher speed than the predetermined low-speed traveling. Sometimes the high-speed engine running means also uses the engine as the driving force source, so when starting normally by depressing the accelerator, the engine is operated from the beginning of the start, and the engine is started in the middle of starting acceleration. Compared with the case of switching from motor traveling to engine traveling, the feeling of stickiness associated with the switching is eliminated and smooth start performance is obtained. on the other hand,When the vehicle is stopped and the brake is fully depressed, both the output of the engine and the electric motor are set to 0 and the hill hold force is set to 100% to hold the vehicle in a stopped state.Brake at a predetermined low speedWhen stepping on a littleIn this case, that is, during creep travel that moves forward or backward simply by adjusting the braking force, the low-speed motor travel meansWhile reducing hill hold powerBecause it travels using only the electric motor as the driving force source, it can fully enjoy the fuel consumption and exhaust gas reduction effects that are one of the characteristics of the hybrid vehicle driving system that includes the engine and the electric motor as the driving power source. it can.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Of the present inventionElectric motor used as a driving force source for travelingAndTherefore, it is desirable to use an inexpensive and compact one that operates at a relatively low voltage of about several tens of volts, but it is also possible to use an electric motor that operates at a high voltage of several hundred volts. As the electric motor, a motor generator capable of generating electric power not only by generating torque as a driving force source but also by being rotationally driven by the kinetic energy of the vehicle is suitably used. As the engine, a gasoline engine or a diesel engine is preferably used.
[0009]
LowThe high-speed engine traveling means and the high-speed engine traveling means are only required to use at least the engine as a driving force source, and both the engine and the electric motor can be used as the driving force source as necessary.
[0010]
  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
  FIG. 1 is a skeleton diagram of a hybrid drive apparatus 10 that is a hybrid vehicle drive system to which the present invention is applied. The hybrid drive device 10 is for an FF (front engine / front drive) vehicle, and includes a gasoline engine 12 that operates by combustion of fuel, an electric motor that operates by electric energy, and a motor generator 14 that functions as a generator. The planetary gear type sub-transmission 16, the belt-type continuously variable transmission 18, and the differential device 20 are provided, and driving force is applied to the left and right front wheels (drive wheels) (not shown) from the output shafts 22R and 22L. Communicated. The input shafts 38 of the engine 12, the motor generator 14, the auxiliary transmission 16, and the continuously variable transmission 18 are arranged on the same axis in that order. The engine 12 and the motor generator 14 correspond to a driving force source for movement and a driving force source for traveling for moving a vehicle as a moving body. The engine 12 is a first driving force source, and the motor generator 14 is The second driving force source has a smaller rated output than the engine 12 and a shorter start time. The continuously variable transmission 18 is a main transmission, and in this embodiment, a gear ratio of about 3 to 11 can be obtained between the output shafts 22R and 22L.
[0011]
  The engine 12 is started by being rotationally driven (cranking) by an electric motor (MO) 60 for starting the engine. The electric motor 60 is a direct current motor and is operated at a low voltage such as about 12V to 36V, and is supplied with electric energy from a battery 26 as a power storage device. The crankshaft 12s of the engine 12 is mechanically connected to the electric motor 60 via a transmission device such as a belt. An auxiliary machine 64 is also connected to the crankshaft 12s via a transmission device such as a belt and an electromagnetic clutch 62, and rotationally drives a compressor of an air conditioner as the auxiliary machine 64. A motor generator 24 is further connected to the crankshaft 12s via a transmission device such as a belt. The motor generator 24 is an electric motor for driving auxiliary equipment, and is supplied with electric energy from a battery 26.
[0012]
  The battery 26 is also operated by supplying electric energy to the motor generator 14. In this embodiment, a battery having a relatively low voltage of about 36 V is used, and the vehicle is running due to regenerative braking of the motor generator 14. Are sequentially charged. When the charged amount SOC of the battery 26 falls below a predetermined value, that is, when the motor generator 14 cannot be operated as an electric motor, the engine 12 is started by the electric motor 60 and the motor generator 24 is driven by the engine 12. The battery 26 is charged by rotating and generating electric power. As a result, it is possible to travel using the motor generator 14 at all times except when a failure occurs. The battery 26 is always secured with a storage amount SOC enough to start the engine 12 by the electric motor 60. In addition, in order to supply electric energy to the electric motor 60, a battery of 12V or the like may be provided separately from the battery 26.
[0013]
  The sub-transmission 16 includes a double planetary first planetary gear device 30 and a simple planetary second planetary gear device 32 that are arranged close to each other in parallel. These planetary gear devices 30 and 32 have a common ring gear R and carrier C, and the pinion gear on the ring gear side of the carrier of the first planetary gear device 30 and the pinion gear of the carrier of the second planetary gear device 32 are integrated. The Ravigneaux type. The motor generator 14 is connected to the sun gear S1 of the first planetary gear device 30, and the engine 12 is connected to the sun gear S2 of the second planetary gear device 32 via the first clutch C1 and the damper device 34. It has become so. The sun gears S1 and S2 are connected by the second clutch C2, and the carrier C is connected to the housing 44 by the reaction force brake B so that the rotation is prevented. The ring gear R is an output member. 36 is connected to the input shaft 38 of the continuously variable transmission 18 via 36. Each of the clutches C1, C2 and the reaction force brake B is of a friction engagement type that is frictionally engaged by a hydraulic actuator.
[0014]
  The sun gear S1 is more engine 12 than the motor generator 14 via a cylindrical connecting member 40 that is disposed through the center of the motor generator 14 that is disposed adjacent to the first planetary gear device 30. The rotor of the motor generator 14 is fixed to an intermediate position of the connecting member 40 so as not to rotate relative to the second clutch C <b> 2 provided on the side. The sun gear S2 is connected to a first clutch C1 provided on the engine 12 side of the motor generator 14 via a connecting member 42 that is inserted through the connecting member 40 and is relatively rotatable. It is connected to the second clutch C2 without going through the first clutch C1. The reaction force brake B is disposed so as to fix a carrier C that extends from between the auxiliary transmission 16 and the motor generator 14 to the outer peripheral side to the housing 44.
[0015]
  As described above, the planetary gear devices 30 and 32 are composed of four rotating elements, that is, the sun gears S1 and S2, the common ring gear R, and the carrier C. Therefore, the number of clutch and brake engaging devices can be reduced. The apparatus is configured simply and compact as a whole. In particular, since it is a Ravigneaux type in which the pinion gear on the ring gear side of the carrier of the first planetary gear unit 30 and the pinion gear of the carrier of the second planetary gear unit 32 are integrated, the number of parts is reduced, and it is easier and more compact. Composed.
[0016]
  The sun gear S1 is connected to the second clutch C2 via a cylindrical connecting member 40 disposed through the center of the motor generator 14, and the rotor of the motor generator 14 is connected to the connecting member 40. The sun gear S2 is fixed to the intermediate position so as not to be relatively rotatable, and the sun gear S2 is connected to the first clutch C1 through a connecting member 42 that is inserted through the connecting member 40 and is relatively rotatable. The connecting member 42 is connected to the second clutch C2 without going through the first clutch C1, and the reaction force brake B housings the carrier C that extends from between the auxiliary transmission 16 and the motor generator 14 to the outer peripheral side. 44, and the ring gear R is connected to the input shaft 38 of the continuously variable transmission 18 through the output member 36 as it is. Gin 12 and the motor generator 14, the reaction force brake B, (such as connecting structure) routing for coupling the output member 36 is simple.
[0017]
  FIG. 2 is a collinear diagram that shows the relationship between the rotational speeds of the rotary elements S1, S2, R, and C of the auxiliary transmission 16 as straight lines, the vertical axis is the rotational speed, and the rotary elements S1, S2, The positions and intervals of R and C are uniquely determined by the connected state and the gear ratios ρ1 and ρ2 of the planetary gear devices 30 and 32. In this alignment chart, the sun gears S1 and S2 that are input rotation elements are located at opposite ends, and the ring gear R that is an output rotation element is a carrier C and a sun gear S1 that are reaction force rotation elements. Is located between. Note that the intervals between the rotating elements S1, S2, R, and C in FIG. 2 are not necessarily accurately represented based on the gear ratios ρ1 and ρ2.
[0018]
  FIG. 3 is a diagram showing the relationship between the engagement states of the clutches C1 and C2 and the reaction force brake B and the shift mode (one example) of the sub-transmission 16, and when the engine 12 is used as a driving force source, the motor generator When 14 is used as a driving force source, or according to the operation position of the shift lever (see FIG. 6) or the like. The “D” position in FIG. 6 is an automatic shift position that travels forward while continuously changing the gear ratio of the continuously variable transmission 18 according to the operating state such as the accelerator operation amount and the vehicle speed in accordance with a predetermined shift condition. The "M" position is a stepped manual shift that changes the gear ratio of the continuously variable transmission 18 stepwise as in the stepped transmission by operating the shift lever to the "+" or "-" position. In the position, the “B” position is a continuously variable manual shift position that continuously changes the gear ratio of the continuously variable transmission 18 in accordance with the position of the shift lever in the front-rear direction. “R” is a reverse position for moving the vehicle backward, “N” is a neutral position, and “P” is a parking position where the vehicle is prevented from traveling by a parking lock mechanism or the like.
[0019]
  In FIG. 3, in the “D”, “M”, and “B” positions where the engine 12 is driven forward using the driving force source, the clutches C1 and C2 are engaged together and the reaction force brake B is released to change the gear ratio. Is set to the high speed forward mode “2nd”. The high speed advance mode “2nd” corresponds to a high speed stage. In this case, if the first clutch C1 is slip-engaged, the engine low speed forward mode “2nd (low speed)” that allows the engine to start is established, and the motor generator Even when the engine 14 cannot be used, the engine 12 can generate creep torque in the forward direction or start the vehicle forward. In the “R” position, by engaging the first clutch C1 and the reaction force brake B and releasing the second clutch C2, the gear ratio is −1 / ρ2 (ρ2 is the gear ratio of the second planetary gear unit 32. (= The number of teeth of the sun gear S2 / the number of teeth of the ring gear R)) is established. In this case, if the first clutch C1 is slip-engaged, the engine low-speed reverse mode “low-speed (engine)” capable of starting the engine is established in the same way as when moving forward, and the storage amount SOC of the battery 26 decreases or malfunctions. Even if the motor generator 14 cannot be used, the creep torque in the reverse direction can be generated by the engine 12 or the vehicle can be started backward. At the “N” position, the clutches C1 and C2 are both released and the reaction force brake B is engaged to cut off the power transmission from the engine 12.
[0020]
  At the “D”, “M”, and “B” positions with the motor generator 14 as the driving force source, the clutch C1 and C2 are both released and the reaction force brake B is engaged to establish the low speed forward mode “1st”. When the vehicle is stopped, a creep torque in the forward direction is generated and the vehicle starts according to the accelerator operation. The gear ratio at this time is 1 / ρ1 (ρ1 is the gear ratio of the first planetary gear unit 30 (= the number of teeth of the sun gear S1 / the number of teeth of the ring gear R)), and a large torque amplification is obtained. Combined with the large gear ratio of the step transmission 18, the motor generator 14 that is operated by a voltage of about 36V can also obtain a practically satisfactory creep torque and start performance. This low speed advance mode “1st” is a low speed stage.
[0021]
  The transition from the low-speed forward mode “1st” to the high-speed forward mode “2nd” by the engine 12 is performed, for example, by releasing the reaction force brake B while engaging the second clutch C2 and rotating the auxiliary transmission 16 integrally. At the same time, the first clutch C1 is engaged after the rotational speed of the engine 12 is synchronized with the sun gear S2, and then the power supply to the motor generator 14 is stopped to bring it into a no-load state.
[0022]
  Further, by engaging both the clutches C1 and C2 and releasing the reaction force brake B, the assist mode “2nd (assist)” with a gear ratio of 1 that travels using both the engine 12 and the motor generator 14 as driving force sources is provided. If the first clutch C1 and the reaction force brake B are disengaged and the second clutch C2 is engaged, the gear ratio for generating the braking force while efficiently charging the motor generator 14 and charging it is established. 1 regenerative braking mode “2nd (regeneration)” is established. In the assist mode “2nd (assist)”, the motor generator 14 may be operated when the high-speed forward mode “2nd” is executed by the engine 12, and in the regenerative braking mode “2nd (regenerative)”, the high-speed advance mode “2nd” is executed. When the forward mode “2nd” is executed, the first clutch C1 is released to disconnect the engine 12, and the motor generator 14 is regeneratively controlled. Further, the assist mode “2nd (assist)” can also be performed by operating the motor generator 14 in the engine low speed forward mode “2nd (low speed)” in which the first clutch C1 is slip-engaged.
[0023]
  Further, in the “R” position where the motor generator 14 is the driving force source, the low speed reverse mode “low speed (motor)” is established by releasing both the clutches C1 and C2 and engaging the reaction force brake B. By generating reverse rotation torque in the motor generator 14, a reverse creep torque is generated when the vehicle is stopped and the vehicle starts moving backward according to the accelerator operation. Since the gear ratio at this time is relatively large at -1 / ρ1, and a large torque amplification is obtained, the motor generator 14 that is operated by a voltage of about 36 V in combination with the large gear ratio of the continuously variable transmission 18 is also practical. A satisfactory creep torque and starting performance can be obtained. This low speed reverse mode “low speed (motor)” is also a low speed stage. The transition from the low speed reverse mode “low speed (motor)” to the high speed reverse mode “high speed” by the engine 12 is to supply power to the motor generator 14 after the engine 12 is operated and the first clutch C1 is engaged. Can be stopped and put into a no-load state.
[0024]
  The use of the engine 12 and the motor generator 14 is determined as shown in a map M1 in FIG. 4A or a map M2 in FIG. 4B, for example, using the vehicle speed and output torque (accelerator operation amount) as parameters. Here, in the map M1 in (a), the engine 12 is used in the region of high vehicle speed and high torque (accelerator operation amount is large), and the motor generator 14 is used in the region of low vehicle speed and low torque (accelerator operation amount is small). However, in this embodiment using the low-voltage motor generator 14, the range of use of the motor generator 14 is relatively narrow and is limited to creep torque when the vehicle is stopped and a slight travel region. The maps M1 and M2 are selected in accordance with vehicle driving conditions such as the storage amount SOC of the battery 26. For example, when the storage amount SOC of the battery 26 is insufficient, the map M2 is selected. Although FIG. 4 is for forward travel, the same applies to reverse travel. In addition, the motor generator 14 can be used in an assisting manner in the above-mentioned “2nd” and “2nd (low speed)” regions where the engine 12 is a driving force source. Moreover, the boundary line of each area | region changes according to the gear ratio of the continuously variable transmission 18, etc.
[0025]
  FIG. 5 is a diagram showing a control system for controlling the operation of the hybrid drive apparatus 10 of the present embodiment. Various signals are input to an ECU (Electronic Control Unit) 50 from switches, sensors, etc. shown on the left side of FIG. In addition, by performing signal processing according to a program stored in advance in a ROM or the like and outputting control signals to various devices shown on the right side, for example, the vehicle speed V and the accelerator opening (accelerator pedal operation amount) θ, The shift mode of the sub-transmission 16 is switched according to the operation state such as the shift position (shift lever operation position), the battery storage amount SOC, the foot brake operation amount, etc., and the operation of the engine 12 and the motor generator 14 is controlled. To do.
[0026]
  The deceleration / torque setting switch 52 shown in FIG. 5 is constituted by a slide switch as shown in FIG. 7, for example, and is arranged near the shift lever. This manually adjusts the regenerative braking torque of the motor generator 14 when the sub-transmission 16 is in the regenerative braking mode “2nd (regeneration)”, and the braking torque increases as it is pulled forward. That is, according to the operation position of the deceleration / torque setting switch 52, the line of the regenerative braking mode “2nd (regenerative)” in FIG. 4 is moved up and down. Further, in the set deceleration indicator 54 of FIG. 8, the set state is displayed by a backward arrow that increases in length as the regenerative braking torque increases in accordance with the operation position of the deceleration / torque setting switch 52. The set deceleration indicator 54 is provided on the instrument panel.
[0027]
  The controller (MO) 66 in FIG. 5 controls the output (torque) of the electric motor 60 for starting the engine. The controller (MG14) 68 and the controller (MG24) 70 are the outputs (torque) of the motor generators 14, 24. ) An inverter that performs control and regenerative control, and the electric oil pump 72 supplies hydraulic pressure to the clutches C1, C2, the brake B, the ABS actuator 74, and the like. The system indicator 76 becomes active when the shift lever is operated to the “M” position or the “B” position, and displays the speed ratio of the entire continuously variable transmission as shown in FIG. If for some reason the gear ratio does not light at the “M” position and “B” position, a fail determination is made. At the time of failure, the gear ratio may be blinked.
[0028]
  FIG. 10 is a characteristic diagram of hill hold oil pressure for maintaining the vehicle in a stopped state. The hill hold hydraulic pressure is a hydraulic pressure of a wheel cylinder provided on the wheel and is controlled by the ABS actuator 74 of FIG. 5 and is controlled according to the pedal stroke of the foot brake. In this embodiment, the pedal stroke is detected in two stages by the foot brake upper switch 78 and the foot brake lower switch 80 of FIG. 5, and the foot brake upper switch 78 is ON and the foot brake lower switch 80 is OFF. Hill holding is performed with 50% hydraulic pressure in the area of BS1 to BS2 where the amount of pedaling (pedal stroke) is small, and hill holding is performed with 100% hydraulic pressure in the area of BS2 or more where the amount of depression is large when the foot brake lower switch 80 is large. To implement. Note that the pedal stroke of the foot brake may be detected continuously, and the hill hold oil pressure may be continuously changed as indicated by the one-dot chain line.
[0029]
  On the other hand, when the engine 12 is started for use as a driving force source, signal processing is performed by the ECU 50 according to the flowchart of FIG. In step S1, input signal processing such as reading various signals necessary for this control is performed. In step S2, the operation position of the shift lever travels based on the signal supplied from the shift position switch 82 (see FIG. 5). It is determined whether the position is “D”, “M”, “B”, or “R”. If it is the travel position, it is determined in step S3 whether or not an engine start condition for using the engine 12 as a drive power source for travel is satisfied, that is, the motor travel mode is shifted to the engine travel mode or the engine + motor travel mode. It is determined whether or not to run, or whether or not the engine 12 is simply started to run. Specifically, in the map M1 in FIG. 4A, the vehicle speed V, the accelerator operation amount θ, and the like are changed from the low speed forward mode “1st” by the motor generator 14 to the engine low speed forward mode “2nd (low speed)” by the engine 12. Alternatively, the engine low speed forward mode “by the engine 12 is switched by switching to the map M2 in FIG. 4 (b), for example, whether or not the condition for shifting to the high speed forward mode“ 2nd ”is satisfied, or when the battery 26 is not fully charged. 2nd (low speed) "or the condition for newly executing the high speed forward mode" 2nd "is satisfied.
[0030]
  If the engine start condition is satisfied, in step S4, the engine 12 is cranked by the engine start electric motor 60, and ignition timing control, fuel injection control, and the like are performed. When this engine start process is executed, the first clutch C1 is released, and the engine 12 is disconnected from the driving force transmission system. Of the signal processing by the ECU 50, the part that executes step S4 functions as an engine starting means. In the next step S5, it is determined whether or not the engine 12 has actually started within a predetermined time. If the engine 12 has started, normal travel control using the engine 12 as a driving force source in step S6. However, if the engine 12 does not start within a predetermined time for some reason such as a failure, step S7 and subsequent steps are executed following step S5, and the driving force is generated using the electric motor 60 for starting the engine. Let Of the signal processing performed by the ECU 50, the part that executes step S5 functions as a start delay determining means.
[0031]
  In step S7, the load on the electric motor 60 that generates the driving force is reduced by releasing the electromagnetic clutch 62 and disconnecting the auxiliary machine 64. In step S8, the first clutch C1 is engaged to connect the engine 12 to the auxiliary transmission 16, and the rotation of the engine 12 passes through the driving force transmission system such as the auxiliary transmission 16 and the belt-type continuously variable transmission 18 to output shaft. Transmission is performed from 22R and 22L to the drive wheels. In addition to the first clutch C1, the second clutch C2 is engaged during forward travel, and the reaction force brake B is engaged during reverse travel. In the MO special control in step S9, the electric motor 60 is operated with a torque larger than that at the time of engine start in step S4, and the driving force is generated while the engine 12 is rotated. Specifically, the output of the electric motor 60 is increased to the maximum exceeding the rated output to compensate for the lack of driving force due to the start delay of the engine 12, and the vehicle can run or a predetermined driving force is generated. To do. Since the electric motor 60 is a DC motor, such control can be easily performed. Of the signal processing by the ECU 50, the portion that executes steps S8 and S9 functions as auxiliary drive control means, and the electric motor 60 for starting the engine corresponds to a third drive force source that is not normally used as a drive force source for travel. To do. In addition, the starting time of the electric motor 60 is sufficiently shorter than that of the engine 12, and the driving force can be generated promptly. The clutches C1, C2 and the brake B are engaging devices that are engaged so that the driving force of the third driving force source is transmitted to the driving wheels.
[0032]
  During the special control of the electric motor 60, the motor generator 14 is also operated to generate a driving force that adds both outputs. That is, not only when shifting to the engine + motor traveling mode, but also when shifting to the engine traveling mode, the motor generator 14 is operated at a predetermined output, and a predetermined driving force is applied together with the electric motor 60 instead of the engine 12. It is generated.
[0033]
  In step S10, it is determined whether or not to stop the MO special control, and if so, step S12 is immediately executed to stop the MO special control. As a stop condition, for example, when the ignition switch 84 (a switch for switching ON / OFF of the drive system of the hybrid vehicle) 84 in FIG. 5 is turned OFF, the shift lever is switched to the “N” position or the “P” position. Or when the MO special control elapses for a predetermined time or more, or when the engine 12 is started when the engine starting process such as fuel injection is continuously performed. In step S11, the charged amount SOC of the battery 26 is set to the lower limit SOC._L1It is determined whether or not the following is satisfied, and SOC ≦ SOC_L1Also in this case, the MO special control is stopped in step S12. Lower limit SOC_L1Is determined based on, for example, whether or not the charged amount SOC of the battery 26 remains to withstand the MO special control.
[0034]
  As described above, when the engine 12 is started in step S4 in order to travel using the engine 12 as a driving force source, the hybrid drive device 10 of the present embodiment, when the engine 12 is started slowly, step S5. Is determined as NO, and step S7 and subsequent steps are executed, and the driving force is generated using the electric motor 60 for starting the engine in addition to the motor generator 14, so that the motor generator 14 as the second driving force source is rated. While adopting an inexpensive and compact one with a small output, start-up delay of the engine 12 and deficiency in driving force due to inability to start are improved. As a result, when shifting from the motor travel mode to the engine travel mode, or when starting with the engine 12 as a driving force source, a feeling of rattling occurs due to a delay in the start of the engine 12 or the engine 12 cannot be started due to the inability to start. Is prevented.
[0035]
  In the above-described embodiment, the shortage of the driving force is compensated by using the electric motor 60 for starting the engine as the third driving force source. However, the shortage of the driving force is compensated by using the motor generator 24 for driving the auxiliary machinery. You can also. That is, in step S 9, instead of using the electric motor 60, the motor generator 24 is power-running to generate a predetermined driving force while rotating the engine 12. The motor generator 24 is an AC motor and is controlled by an inverter. However, by designing the motor generator 24 so that a large current can flow in advance, a large torque exceeding the rated output can be generated temporarily.
[0036]
  It is also possible to start the engine 12 using the motor generator 24, in which case the electric motor 60 can be omitted.The
[0037]
  FIG. 12 shows a case where the motor generator 14 used as the second driving force source for running the vehicle is specially controlled to compensate for the driving force shortage accompanying the start delay of the engine 12, and steps SS1 to SS6 are shown in FIG. Substantially the same as steps S1 to S6. In step SS7, the motor generator 14 is adjusted by increasing the amount of electric energy supplied from the battery 26 so as to compensate for the shortage of driving force associated with the start delay of the engine 12. Drive with a large torque exceeding the rated output. The motor generator 14 is an AC motor and is controlled by an inverter. However, by designing it so that a large current can flow in advance, a large torque exceeding the rated output can be generated temporarily.
[0038]
  In step SS8, it is determined whether or not to cancel the MG special control in step SS7, and if so, step SS11 is immediately executed to stop the MG special control. As a stop condition, for example, when the ignition switch 84 is turned off, when the shift lever is switched to the “N” position or the “P” position, the engine start process in step SS4 is continuously performed. For example, when the engine 12 is started. In step SS9, the storage amount SOC of the battery 26 is set to the lower limit SOC._L2In step SS10, it is determined whether or not the duration TS of the MG special control has reached a predetermined time T1 or more, and SOC ≦ SOC_L2Alternatively, even when TS ≧ T1, MG special control is stopped in step SS11. Lower limit SOC_L2Is determined based on, for example, whether or not the storage amount SOC of the battery 26 remains to withstand MG special control, and the predetermined time T1 is based on the thermal limit of the motor generator 14 due to continuous high output. Determined.
[0039]
  In this case, the same effect as in the above embodiment can be obtained. In particular, in the case of an engine start delay at the time of transition from the motor travel mode to the engine travel mode or the engine + motor travel mode, the motor generator 14 used in the motor travel mode is used as it is and pulled to a high torque. Therefore, as compared with the case where the driving force is generated by using another electric motor 60 or motor generator 24 as in the above embodiment, the driving force can be increased smoothly and the control is easy.
[0040]
EOf the signal processing by the CU 50, the part that executes step SS4 functions as engine starting means, the part that executes step SS5 functions as starting delay determining means, and the part that executes step SS7 is auxiliary drive control means. Is functioning as
[0041]
  13 and 14 areThe present inventionIn one embodiment, the hybrid drive device 10Suitable forAnd is executed by signal processing by the ECU 50. In step Q1, input signal processing such as reading various signals necessary for this control is performed. In step Q2, the shift lever operating position is set to the travel position, that is, “D” based on the signal supplied from the shift position switch 82. ”,“ M ”,“ B ”, or“ R ”. If it is the traveling position, the charged amount SOC of the battery 26 in step Q3 is the lower limit SOC._L3Determine whether or not, SOC ≦ SOC_L3In this case, in step Q4, the vehicle travels with only the engine 12 as the driving force source according to the map M2 shown in FIG. 4 (b), but SOC> SOC_L3If so, step Q5 and subsequent steps are executed. Lower limit SOC_L3Is determined based on, for example, whether or not the stored amount SOC of the battery 26 remains so that the motor generator 14 can be driven by power running control.
[0042]
  In step Q5, it is determined whether or not the foot brake has been depressed almost completely based on whether or not the foot brake lower switch 80 is ON. In the case of ON, the vehicle speed V is set to a constant low vehicle speed that is predetermined in step Q6. V_L1It is determined whether or not: Step Q6 is for determining whether or not the vehicle is substantially stopped._L1Is set to a value of approximately 0 in consideration of the detection error of the sensor, and V ≦ V_L1If so, in step Q7, the outputs of the engine 12 and the motor generator 14 are both set to 0 to save fuel and power. In step Q8, as shown in FIG. 10, the hill hold oil pressure is set to 100%, and the wheel brake is operated with a high oil pressure to hold the vehicle in a stopped state.
[0043]
  If the determination in step Q5 is NO, that is, if the brake lower switch 80 is OFF, step Q9 and subsequent steps in FIG. 14 are executed. If the determination in step Q6 is NO, that is, the vehicle speed V is the low vehicle speed V._L1If larger, step Q11 and subsequent steps in FIG. 14 are executed. In step Q9, it is determined whether or not the foot brake is depressed a little (BS1 to BS2) based on whether or not the foot brake upper switch 78 is ON. If it is ON, the vehicle speed V is predetermined in step Q14. Constant low vehicle speed V_L2It is determined whether or not: Low vehicle speed V_L2Is, for example, approximately the same vehicle speed as the maximum vehicle speed in the low-speed forward mode “1st” in the map M1 in FIG._L2If so, the motor generator 14 is controlled in step Q15 and the hill hold force is reduced to 50% in step Q16. The torque of the motor generator 14 is set to a magnitude that generates a creep torque that the vehicle advances little by little on a substantially horizontal flat road regardless of the hill hold force (50%) and the braking force of the foot brake. The same setting is made during reverse travel. Therefore, the amount of foot brake depression (pedal stroke) is relatively small (within the range of BS1 to BS2), and the vehicle speed V is low._L2In the following cases, even when the accelerator is OFF, the vehicle is moved forward and backward by the motor generator 14, and creep driving can be performed only by the strength of the brake operation, as in a general automatic vehicle equipped with a torque converter.
[0044]
  On the other hand, when the determination at step Q9 is NO, that is, when the foot brake is not depressed, or when the determination at step Q14 is NO, that is, when the foot brake is ON, the vehicle speed V is low._L2If larger, step Q10 and subsequent steps are executed. In step Q10, a map M2 in FIG. 4B is set to travel using only the engine 12 as a driving force source. In step Q11,With electric motor 60 etc.The engine 12 is started and the vehicle travels while switching the shift mode according to the map M2. In step Q12, the shift control of the continuously variable transmission 18 is performed according to the driving state such as the vehicle speed V and the accelerator operation amount θ or the shift lever operation, and in step Q13, the hill hold is completely released.
[0045]
  In this embodiment, when the foot brake is not depressed (step Q9 is NO), the vehicle travels using only the engine 12 as a driving force source according to the map M2, and therefore, at the start of normal starting when the accelerator is depressed, the vehicle starts at the start. Compared with the case where the engine 12 is operated and the engine 12 is started in the middle of starting acceleration and the engine 12 is started and switched from the motor driving to the engine driving, the feeling of stickiness associated with the switching is eliminated and the vehicle starts smoothly. Performance is obtained. On the other hand, the foot brake depression amount (pedal stroke) is relatively small (within the range of BS1 to BS2) and the vehicle speed V is low._L2In the following cases (YES in step Q14), in other words, when creeping with only the strength of the brake operation, traveling is performed using only the motor generator 14 as a driving force source, and thus fuel consumption that is one of the characteristics of the hybrid drive device 10 And the exhaust gas reduction effect can be fully enjoyed.
[0046]
  In this case, the part that executes step Q15 in the signal processing by the ECU 50 functions as a low-speed motor traveling means, and the part that executes step Q11 functions as a low-speed engine traveling means and a high-speed engine traveling means.
[0047]
  As mentioned above, although the Example of this invention was described in detail based on drawing, these are one embodiment to the last, and this invention is implemented in the aspect which added the various change and improvement based on the knowledge of those skilled in the art. be able to.
[Brief description of the drawings]
FIG. 1 is a skeleton diagram of a hybrid drive device which is an example of a hybrid vehicle drive system to which the present invention is applied.
FIG. 2 is a collinear diagram that shows, in a straight line, the mutual relationship between the rotational speeds of the rotary elements of the sub-transmission of FIG. 1;
3 is a diagram showing a relationship between a shift mode established in the sub-transmission shown in FIG. 1 and an engagement state of the engagement device.
FIG. 4 is a diagram for explaining the proper use of a motor generator and an engine in the hybrid drive device of FIG. 1;
FIG. 5 is a block diagram illustrating a control system of the hybrid drive device of FIG. 1;
6 is a diagram showing a shift position of the hybrid drive device of FIG. 1. FIG.
7 is a diagram showing a deceleration / torque setting switch provided in the hybrid drive device of FIG. 1. FIG.
8 is a diagram showing an indicator that displays a setting state of a deceleration / torque setting switch in FIG. 7;
FIG. 9 is a diagram showing a system indicator that becomes active and displays a gear ratio when the shift lever is operated to the “M” or “B” position in FIG. 6;
FIG. 10 is a diagram showing a relationship between hill hold oil pressure and brake pedal stroke.
FIG. 11 is a flowchart for explaining an operation when starting to use an engine as a driving force source for running a vehicle.
FIG. 12 is a flowchart for explaining another embodiment and corresponding to FIG.
13 together with FIG. 14, the driving force source is switched by turning on and off the foot brake.The present inventionIt is a flowchart explaining one Example.
14 together with FIG. 13, the driving force source is switched by turning on and off the foot brake.The present inventionIt is a flowchart explaining one Example.
[Explanation of symbols]
  10: Hybrid drive device (vehicle drive system) 12: Engine 14: Motor generator (electric motor) 78: Foot brake upper switch 80: Foot brake lower switch
  Step Q11, Q13: Low-speed engine running means, high-speed engine running means
  Step Q15, Q16: Low-speed motor travel means

Claims (1)

In a hybrid vehicle drive system including an engine that operates by combustion of fuel and an electric motor that operates by electric energy, as a driving power source for traveling the vehicle,
When the vehicle is stopped and when the brake is fully depressed, the foot brake pedal stroke is larger than the predetermined BS2, the outputs of the engine and the electric motor are both set to 0 and the vehicle is kept stopped. While holding the vehicle at 100% hold force,
When the brake is depressed slightly in the region of BS1 to BS2 when the predetermined braking speed is predetermined and the pedal stroke of the foot brake is smaller than that when the brake is fully depressed, the hill hold force is greater than when the brake is fully depressed. Low-speed motor traveling means for reducing and traveling using only the electric motor as a driving force source;
When the brake is OFF at the predetermined low speed and the foot brake pedal stroke is smaller than when the brake is slightly depressed , the hill hold force is completely released and the low speed at which the engine is used as a driving force source Engine running means;
High-speed engine traveling means that travels using the engine as a driving force source while completely releasing the hill hold force when traveling at a speed higher than the predetermined low-speed traveling;
A vehicle drive system comprising:

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