JP6044179B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control apparatus for a hybrid vehicle using an engine and a motor as power sources.

  Vehicles that use an engine and a motor as a power source A so-called hybrid vehicle has multiple driving patterns, such as engine-driven running using only engine power, parallel-drive running using engine power and motor power, and motor-driven running using only motor power. Have.

  In such a hybrid vehicle, when shifting from parallel driving to motor driving, the clutch between the engine and the motor is released to stop the engine, but the engine vibrates immediately before the engine stops, and the vibration May be transmitted to the occupant through the vehicle body and may cause discomfort to the occupant.

  On the other hand, when the engine is stopped, the clutch between the engine and the actuator (motor) is released, and then the clutch is engaged (connected) when the rotation speed of the actuator is reduced, and a load is applied to the engine. There has been known a vehicle in which the degree of decrease in the engine speed is increased to reduce the time during which the engine speed remains in the resonance region, thereby suppressing engine vibration (for example, Patent Document 1).

JP 2009-204065 A

  As described above, in the case of suppressing engine vibration by applying a load to the engine by engaging the clutch, the number of rotations of the actuator and the engagement of the clutch based on the number of rotations so that an unnecessary load is not applied from the actuator to the engine. It is necessary to capture timing appropriately. For this reason, there is a problem that a rotational speed sensor dedicated to the actuator is required, and the number of parts increases or the control becomes complicated. An increase in the number of parts leads to an increase in cost.

  An object of the present invention is to provide a vehicle control device that can eliminate unnecessary vibrations when the engine is stopped without increasing the number of parts or complicating the control.

  According to a first aspect of the present invention, there is provided a vehicle control device for a vehicle in which a motor is connected to an output shaft of an engine via a clutch, and the power of the engine or the motor is transmitted to driving wheels via the output shaft of the motor. The clutch is disengaged from the engine travel mode in which the clutch is engaged with a predetermined engagement force to transmit the engine power to the drive wheel and travels, and only the motor power is applied to the drive wheel. After the transition to the motor travel mode in which the motor travels by transmission, the motor is re-engaged with an engagement force smaller than the predetermined engagement force when the rotational speed of the engine decreases at a decrease rate of a predetermined value or more. Control means for transmitting power from the engine to the engine.

  The vehicle control apparatus according to the second aspect of the invention is dependent on the first aspect of the invention and limits the control means. That is, the control means engages the clutch with an engagement force smaller than the predetermined engagement force when the rate of decrease in the engine rotation speed is equal to or greater than the predetermined value and the engine rotation speed is equal to or less than a set value. To do.

  The vehicle control device of the invention according to claim 3 is dependent on the invention according to claim 1 or claim 2 and limits the control means. That is, when engaging the clutch with an engagement force smaller than the predetermined engagement force, the control means increases the drive torque of the motor if the drive torque of the motor is less than a predetermined value.

The vehicle control device of the invention according to claim 4 is dependent on the invention according to claim 3 and limits the control means. That is, when the clutch is engaged with an engagement force smaller than the predetermined engagement force, the control means maintains the motor drive torque as it is if the motor drive torque is equal to or greater than the predetermined value. .

  The vehicle control device of the invention according to claim 5 is dependent on the invention according to any one of claims 1 to 4 and limits the control means. In other words, when the clutch is engaged with an engagement force smaller than the predetermined engagement force, the control means increases the engagement force of the clutch as the rate of decrease in the engine speed increases.

  According to the present invention, unnecessary vibrations when the engine is stopped can be eliminated without increasing the number of parts or complicating the control.

The block diagram which shows the structure of one Embodiment of this invention. The flowchart which shows the control of the same embodiment. The time chart which shows an example of the engine speed of the same embodiment, the state of a clutch, and the drive torque command value of a motor. The figure which shows the state which suppressed the fluctuation | variation of the engine speed of the embodiment. The time chart which shows the other example of the engine speed of the same embodiment, the state of a clutch, and the drive torque command value of a motor.

Hereinafter, an embodiment of the present invention will be described.
As shown in FIG. 1, an output shaft (also referred to as a rotating shaft) of a motor 3 is connected to an output shaft of the engine 1 via a clutch 2, and an automatic transmission 4 and a differential device 5 are connected to the output shaft of the motor 3. The axle 7 of the drive wheel 6 is connected through the via. The engine 1, the clutch 2, the motor 3, and the automatic transmission 4 are in a so-called serial relationship.

  The clutch 2 disconnects the output shaft of the engine 1 and the output shaft of the motor 3 when released, and connects the output shaft of the engine 1 and the output shaft of the motor 3 when engaged (connected). That is, at the time of opening, only the driving torque Tm of the motor 3 is transmitted to the automatic transmission 4, and motor driving traveling only by the output of the motor 3 becomes possible (motor traveling mode). At the time of engagement, the driving torque Te of the engine 1 and the driving torque Tm of the motor 3 are transmitted to the automatic transmission 4, and the engine driving traveling only by the output of the engine 1 or the parallel driving traveling by the output of the engine 1 and the output of the motor 3 is performed. It becomes possible (engine running mode). Whether the clutch 2 is to be released or engaged is appropriately selected by a control unit 50, which will be described later, in accordance with the traveling state of the vehicle, the amount of power stored in the battery power source 40, which will be described later, and the like.

  The clutch 2 can be engaged with an arbitrary engagement force (also referred to as an engagement amount) in the range of a minimum of 0% to a maximum of 100% in accordance with the displacement of the built-in hydraulic piston. The minimum engagement force of 0% is in the released state. The smaller the engagement force, the smaller the amount of torque transmitted, and the greater the engagement force, the greater the amount of torque transmitted.

  The automatic transmission 4 has a torque converter 20 in addition to the transmission main body 10. The torque converter 20 includes an impeller 21 connected to the output shaft of the motor 3, a turbine 22 connected to the transmission main body 10, a viscous fluid for power transmission existing between the impeller 21 and the turbine 22, and the motor The drive torque transmitted from 3 is amplified and transmitted to the transmission main body 10.

  The DC voltage of the battery power supply 40 is converted into an AC voltage having a predetermined frequency and a level corresponding to the frequency by the inverter function of the power converter 42, and this is applied to the stator winding of the motor 3. By this application, the motor 3 operates. When the rotation of the drive wheel 6 is transmitted to the output shaft of the motor 3 via the axle 7, the differential device 5, and the automatic transmission 4, such as when the vehicle is idling or braking, the motor 3 functions as a generator, An AC voltage is output from the motor 3. This AC voltage is converted into a DC voltage of a predetermined level by the converter function of the power converter 42, and the battery power supply 40 is charged as regenerative energy.

  On the other hand, the engine 1, the clutch 2, the transmission main body 10, the power converter 42, the accelerator opening sensor 51, the vehicle speed sensor 52, and the crank angle sensor 53 are connected to the control unit 50. The accelerator opening sensor 51 detects the opening of the accelerator pedal of the vehicle. The vehicle speed sensor 52 detects the traveling speed of the vehicle. The crank angle sensor 53 detects a crank angle that is linked to the vertical movement of the piston of the engine 1. The rotation speed Ne of the engine 1 can be detected from the detection angle of the crank angle sensor 53.

The control unit 50 includes the following means (1) to (6) as main functions.
(1) The map data for setting the target drive torque Tt stored in the internal memory is referred to based on the detected opening of the accelerator opening sensor 51, the detected vehicle speed of the vehicle speed sensor 52, the shift position of the automatic transmission 4, and the like. Thus, setting means for setting the target drive torque Tt.

  (2) During engine drive running (engine running mode) in which the clutch 2 is engaged with a predetermined engagement force (for example, a maximum engagement force of 100%) and only the power of the engine 1 is transmitted to the drive wheels 6, the engine is driven. 1st control means which controls the output of the engine 1 so that 1 drive torque Te becomes the set target drive torque Tt.

  (3) During parallel drive travel (engine travel) in which the clutch 2 is engaged with a predetermined engagement force (for example, a maximum engagement force of 100%) and the power of the engine 1 and the power of the motor 3 are transmitted to the drive wheels 6. Mode), second control means for controlling the output of the engine 1 and the output of the power converter 42 so that the sum of the drive torque Te of the engine 1 and the drive torque Tm of the motor 3 becomes the set target drive torque Tt.

  (4) During motor drive travel (motor travel mode) in which the engine 1 is disconnected by releasing the clutch 2 (engagement force 0%) and only the power of the motor 3 is transmitted to the drive wheels 6 (motor travel mode), the drive torque Tm of the motor 3 3rd control means which controls the output of the power converter 42 so that becomes the set target drive torque Tt.

  (5) Fourth control means for selectively setting any one of the engine driving traveling, parallel driving traveling, and motor driving traveling according to the traveling state of the vehicle, the amount of power stored in the battery power source 40, and the like.

  (6) From the engine travel mode in which the clutch 2 is engaged with the predetermined engagement force and the power of the engine 1 is transmitted to the drive wheels 6 to travel, the clutch 2 is released and only the power of the motor 3 is driven. After the transition to the motor travel mode in which the vehicle travels by transmitting to the clutch 2, when the rotational speed Ne of the engine 1 (hereinafter referred to as engine rotational speed) Ne decreases at a reduction rate θe that is equal to or greater than a certain value, Fifth control means for re-engaging with a small engagement force and transmitting power from the motor 3 to the engine 1. Specifically, when the rotational speed Ne of the engine 1 decreases at a reduction rate θe that is equal to or greater than a certain value during the transition from parallel drive travel to motor drive travel, the clutch 2 is engaged less than the maximum engagement force 100%. For example, the engagement is performed with a substantially half engagement force of 50%. The engine speed Ne is detected from the detection angle of the crank angle sensor 53. The decrease rate θe of the rotational speed Ne is the rotational speed decrease amount ΔNe per unit time Δt (θe = ΔNe / Δt).

Next, the control executed by the control unit 50 will be described with reference to the flowchart of FIG. 2 and the time charts of FIGS.
At the time of transition from parallel drive travel that travels by the output of the engine 1 and monitor output to motor drive travel that travels by the output of the motor 3 (YES in step 101), that is, the clutch 2 is released and the engine 1 is stopped. When traveling with only the output of the motor 3, the decrease rate θe of the engine speed Ne is detected (step 102).

  At this time, as the stop control of the engine 1, a control for gradually closing the throttle valve opening of the engine 1 is executed so that the engine speed Ne gradually decreases. The reduction rate θe of the actual engine speed Ne is detected.

  If the detected decrease rate θe is less than a certain value (NO in step 103), the detection of the decrease rate θe is repeated (step 102).

  As the engine speed Ne decreases, even if the throttle valve opening is controlled so that the engine speed Ne gradually decreases, the fluctuation of the engine speed Ne gradually increases.

  When the detected decrease rate θe is equal to or greater than a certain value (YES in step 103), the engine speed Ne at that time is compared with a set value Ne2, for example, 300 rpm (step 104). If the engine speed Ne is higher than the set value Ne2 (NO in Step 104), the detection of the decrease rate θe is repeated (Step 102).

  When the detected decrease rate θe is equal to or greater than a certain value (YES in step 103), if the engine speed Ne at that time is equal to or less than the set value Ne2 (YES in step 104), the engine speed Ne at that time is the set value. Ne1 (<Ne2) For example, on the condition that it is 100 rpm or more (YES in Step 105), the driving torque Tm of the motor 3 is compared with the set value Tma (Step 106).

  In the low engine speed range where the engine speed Ne is equal to or less than the set value Ne2 and equal to or greater than the set value Ne1, in addition to the decrease rate θe being equal to or greater than a certain value, the fluctuation of the engine speed Ne gradually increases and the engine 1 This is a region where vibration is likely to occur.

  If the drive torque Tm of the motor 3 is equal to or greater than the set value Tma (YES in step 106), the clutch 2 is kept for t1 time in accordance with the decrease in the engine speed Ne while maintaining the command value for the drive torque Tm. Engage with only 50% engaging force (step 107). Engagement with an engagement force of 50% is a so-called half-clutch connection.

  In this way, a part of the drive torque Tm of the motor 3 is transmitted to the output shaft of the engine 1 by connecting the clutch 2 to the half clutch. Thereby, as shown in FIG. 4, the big fluctuation | variation of the engine speed Ne in a low speed area | region can be suppressed. By suppressing large fluctuations in the engine speed Ne, unnecessary vibration of the engine 1 can be eliminated. Therefore, it is possible to avoid a problem that unnecessary engine vibration is transmitted to the passenger through the vehicle body and gives the passenger an uncomfortable feeling.

  In this case, since the drive torque Tm is equal to or greater than the set value Tma, even if the clutch 2 is in a half-clutch connection and a part of the drive torque Tm is transmitted to the output shaft of the engine 1, a sufficient actual drive torque for traveling is ensured. Can do. As a result, stable motor-driven running without a feeling of deceleration can be continued.

  Since only a part of the driving torque Tm is transmitted to the engine 1 side by the half-clutch connection of the clutch 2, no extra load is applied to the engine 1. When an extra load is applied to the engine 1, the engine speed Ne may drop suddenly and cause a large engine vibration, but such a problem can be avoided.

  The detection of the engine speed Ne is essential for engine control, and the control unit 50 can grasp the driving torque Tm of the motor 3 from its own control. Increases and associated cost increases can be avoided.

  In addition, when the clutch 2 is engaged with an engagement force of 100%, all of the driving torque Tm is transmitted to the engine 1, so that the engagement timing of the clutch 2 is appropriately controlled so as not to transmit excessive torque. However, since only a small torque is transmitted to the engine 1 by connecting the clutch 2 to the half-clutch, excessive torque is not transmitted to the engine 1 and it is possible to avoid complicated control at that point. it can.

  On the other hand, when the rate of decrease θe is equal to or greater than a certain value (YES in step 103) and the engine speed Ne enters a low speed range that is equal to or less than the set value Ne2 and equal to or greater than the set value Ne1, (YES in step 104, step 105). If the drive torque Tm of the motor 3 is less than the set value Tma (NO in step 106), as shown in FIG. 5, the command value for the drive torque Tm is set to t1 in accordance with the decrease in the engine speed Ne. ΔTm is increased by time (step 108). ΔTm is a value corresponding to the difference between the current driving torque Tm and the set value Tma. Then, the clutch 2 is engaged with an engagement force of 50% for t1 time in accordance with the decrease in the engine speed Ne (step 107).

  As described above, when the driving torque Tm is less than the set value Tma, the clutch 2 is connected to the half clutch while increasing the driving torque Tm, so that even if a part of the driving torque Tm is transmitted to the output shaft of the engine 1, A sufficient actual driving torque for traveling can be ensured. As a result, stable motor-driven running without a feeling of deceleration can be continued.

  As shown in FIG. 4, large fluctuations in the engine speed Ne in the low speed region can be suppressed while continuing stable motor-driven travel without a feeling of deceleration. As a result, the unnecessary vibration of the engine 1 can be eliminated.

  When the engine speed Ne falls below the set value Ne1 (NO in step 105), the control is terminated. The engine speed Ne becomes zero and the engine 1 is completely stopped.

  In the above embodiment, the clutch 2 is half-clutch connected on condition that the rate of decrease θe of the engine speed Ne is a certain value or more and the engine speed Ne is in the low speed range. However, the clutch 2 may be half-clutch connected only if the decrease rate θe of the engine speed Ne is equal to or greater than a certain value. By so doing, fluctuations in the engine speed Ne can be suppressed even outside the low speed range.

  Further, in the above embodiment, the engagement force of 50% is engaged as the half-clutch connection of the clutch 2, but the actual engagement force of the half-clutch connection is the capacity of the clutch 2, the rated output of the motor 3, the engine It can be appropriately selected according to the displacement of 1 or the number of cylinders.

  A value proportional to the decrease rate θa of the engine speed Ne may be set for the actual engagement force of the half-clutch connection. That is, when the decrease rate θa of the engine speed Ne is small, the fluctuation of the engine speed Ne is also small. Therefore, the engagement force of the clutch 2 is reduced and the amount of torque transmitted to the engine 1 is reduced. When the decrease rate θa of the engine speed Ne is large, the fluctuation of the engine speed Ne is also large. Therefore, the engagement force of the clutch 2 is increased and the torque transmission amount to the engine 1 is increased. Thus, by making the engagement force of the clutch 2 variable so that the engagement force of the clutch 2 increases as the decrease rate θa of the engine rotation speed Ne increases, the magnitude of the actual fluctuation of the engine rotation speed Ne is increased. Appropriate fluctuation suppression can be achieved.

  Also for the time t1 when the clutch 2 is half-clutch connected, a value proportional to the decrease rate θe of the engine speed Ne may be variably set.

  Further, when the drive torque Tm of the motor 3 is less than the set value Tma, the drive torque Tm is increased by ΔTm, and a value corresponding to the difference between the current drive torque Tm and the set value Tma is set as the ΔTm. As for ΔTm, a value proportional to the decrease rate θe of the engine speed Ne may be variably set.

  The above embodiments are presented as examples, and are not intended to limit the scope of the invention. The novel embodiments and modifications can be implemented in various other forms, and various omissions, rewrites, and changes can be made without departing from the spirit of the invention. In these embodiments and modifications, the scope of the invention is included in the gist, and is included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Clutch, 3 ... Motor, 4 ... Automatic transmission, 5 ... Differential gear, 6 ... Drive wheel, 7 ... Axle, 10 ... Transmission main body, 20 ... Torque converter, 21 ... Impeller, 22 ... Turbine, 40 ... battery power source, 42 ... power converter, 51 ... accelerator opening sensor, 52 ... vehicle speed sensor, 53 ... crank angle sensor

Claims (5)

A vehicle control device for a vehicle, in which a motor is connected to an output shaft of an engine via a clutch, and the power of the engine or the motor is transmitted to driving wheels via the output shaft of the motor,
The engine is disengaged from the engine travel mode in which the clutch is engaged with a predetermined engagement force and the engine power is transmitted to the drive wheels, and only the motor power is transmitted to the drive wheels. After the transition to the motor running mode, the clutch is re-engaged with an engagement force smaller than the predetermined engagement force when the engine speed decreases at a reduction rate of a predetermined value or more, and the motor is connected to the engine. Control means for transmitting power,
A vehicle control device comprising: The control means includes
Engaging the clutch with an engagement force less than the predetermined engagement force when the rate of decrease in the engine rotation rate is equal to or greater than the predetermined value and the engine rotation rate is equal to or less than a set value;
The vehicle control device according to claim 1. The control means includes
When the clutch is engaged with an engagement force smaller than the predetermined engagement force, if the drive torque of the motor is less than a predetermined value, the drive torque of the motor is increased.
The vehicle control device according to claim 1, wherein the vehicle control device is a vehicle control device. The control means includes
When the clutch is engaged with an engagement force smaller than the predetermined engagement force, if the drive torque of the motor is not less than the predetermined value, the drive torque of the motor is maintained as it is.
The vehicle control device according to claim 3. The control means includes
When engaging the clutch with an engagement force smaller than the predetermined engagement force,
The clutch engagement force is increased as the rate of decrease in the engine speed increases.
The vehicle control device according to any one of claims 1 to 4, wherein the vehicle control device is provided.

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