JP2012224304A - Damping control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease vibration that can be generated caused by the output torque of an engine while reducing the sound that can be generated caused by damping control.SOLUTION: An ECU eliminates the vibration caused by the output torque of the engine by controlling the output torque of a motor-generator according to the output torque of the engine and executes decreasing damping control. During execution of the start processing of the engine, concretely during the cranking of the engine (when YES in S100), the prescribed gain G1 is used in the damping control in S104 before the initial explosion (YES in S102). That is, gain G1 is used as for the period from the cranking to the initial explosion. When it is after the initial explosion (NO in S102), the prescribed gain G2 that differs from the gain G1 is used in S106.

Description

  The present invention relates to a vehicle vibration damping control device, and more particularly, to a technique for changing a gain used in vibration damping control for reducing vibration caused by engine output torque.

  In addition to the engine, a hybrid vehicle equipped with an electric motor as a drive source is known. Hybrid vehicles may be classified as a type of electric vehicle. The hybrid vehicle can travel using only the electric motor while the engine is stopped. When the hybrid vehicle travels in such a manner, there is no torque output from the engine, so vibration generated in the vehicle is very small. However, for example, when the engine is started, the fluctuation in the output torque of the engine is large, so that the vibration generated in the vehicle due to the output torque of the engine can be large. Such vibration can cause discomfort to the passenger.

  Therefore, as described in Japanese Patent Application Laid-Open No. 2008-24022 (Patent Document 1), by controlling the output torque of the electric motor according to the output torque of the engine, vibration caused by the output torque of the engine is canceled and reduced. The vibration suppression control is executed.

Japanese Patent Laid-Open No. 2008-24022

  However, for example, if the damping torque output from the electric motor is constantly increased in order to cancel the vibration by increasing the gain with respect to the output torque of the engine, the vibration is effectively reduced under a driving situation where a large vibration can occur. On the other hand, the vehicle is vibrated on the contrary by the damping torque output from the electric motor in a driving situation where large vibrations are unlikely to occur. For example, in the process of starting the engine, a large vibration can be generated at the first explosion, while a vibration that can be generated after the first explosion is reduced, so that a large gain is not necessary. If the gain remains large, sound may be generated in the vehicle due to vibration of the vehicle by the electric motor.

  The present invention has been made in view of the above-described problems, and an object thereof is to reduce vibration while reducing sound that can be generated.

  A vibration suppression control device for a vehicle cranks the engine by using a vibration suppression control means for outputting torque for reducing vibration caused by torque output from the engine and a gain used in the vibration suppression control means. And a changing means for changing the period from the first explosion to the period after the first explosion.

  According to this configuration, the gain used in the vibration suppression control is appropriately determined for each of the period from the cranking of the engine to the first explosion and the period after the first explosion. For example, the gain is increased during the period up to the first explosion when large vibrations can occur, while the gain is decreased during the period after the first explosion when large vibrations are unlikely to occur. Thereby, while the vibration is effectively reduced in the period before the first explosion, the sound that can be generated due to the vibration suppression control can be reduced in the period after the first explosion.

1 is an overall block diagram of a vehicle. It is a figure which shows the alignment chart of a power split device. It is a figure which shows the flowchart of the process which ECU performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, an overall block diagram of a vehicle 1 according to the present embodiment will be described. The vehicle 1 includes an engine 10, a drive shaft 16, a first motor generator (hereinafter referred to as a first MG) 20, a second motor generator (hereinafter referred to as a second MG) 30, and a power split device 40. , A reduction gear 58, a PCU (Power Control Unit) 60, a battery 70, a drive wheel 80, a start switch 150, a braking device 151, and an ECU (Electronic Control Unit) 200.

  The vehicle 1 travels with driving force output from at least one of the engine 10 and the second MG 30. The power generated by the engine 10 is divided into two paths by the power split device 40. One of the two routes is a route transmitted to the drive wheel 80 via the speed reducer 58, and the other route is a route transmitted to the first MG 20.

  First MG 20 and second MG 30 are, for example, three-phase AC rotating electric machines. First MG 20 and second MG 30 are driven by PCU 60.

  The first MG 20 has a function as a generator that generates power using the power of the engine 10 divided by the power split device 40 and charges the battery 70 via the PCU 60. Further, first MG 20 receives electric power from battery 70 and rotates a crankshaft that is an output shaft of engine 10. Thus, the first MG 20 has a function as a starter for starting the engine 10.

  Second MG 30 has a function as a driving motor that applies driving force to driving wheels 80 using at least one of the electric power stored in battery 70 and the electric power generated by first MG 20. Second MG 30 also has a function as a generator for charging battery 70 via PCU 60 using electric power generated by regenerative braking.

  The engine 10 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine. The engine 10 includes a plurality of cylinders 102 and a fuel injection device 104 that supplies fuel to each of the plurality of cylinders 102. Based on the control signal S1 from the ECU 200, the fuel injection device 104 injects an appropriate amount of fuel to each cylinder at an appropriate time, or stops fuel injection to each cylinder.

  Furthermore, the engine 10 is provided with an engine rotation speed sensor 11 for detecting the rotation speed Ne (hereinafter referred to as engine rotation speed) Ne of the crankshaft of the engine 10. The engine rotation speed sensor 11 transmits a signal indicating the detected engine rotation speed Ne to the ECU 200.

  Power split device 40 mechanically connects each of the three elements of drive shaft 16 for rotating drive wheel 80, the output shaft of engine 10 and the rotation shaft (output shaft) of first MG 20. The power split device 40 enables transmission of power between the other two elements by using any one of the three elements described above as a reaction force element. The rotation shaft (output shaft) of second MG 30 is connected to drive shaft 16.

  Power split device 40 is a planetary gear mechanism including sun gear 50, pinion gear 52, carrier 54, and ring gear 56. Pinion gear 52 meshes with each of sun gear 50 and ring gear 56. The carrier 54 supports the pinion gear 52 so as to be capable of rotating, and is connected to the crankshaft of the engine 10. Sun gear 50 is coupled to the rotation shaft of first MG 20. Ring gear 56 is coupled to the rotation shaft of second MG 30 and reduction gear 58 via drive shaft 16.

  When engine 10, first MG 20 and second MG 30 are connected by power split device 40, rotation speed Nm1 of first MG 20, engine rotation speed Ne, and rotation speed Nm2 of second MG 30 are on the collinear diagram of FIG. Thus, the rotational speeds Nm1, Ne, and Nm2 of each element change so as to maintain the relationship connected by one straight line.

  The left vertical axis of the three vertical axes in the alignment chart shown in FIG. 2 indicates the rotational speed of the sun gear 50, that is, the rotational speed Nm1 of the first MG 20. Further, the vertical axis at the center of the alignment chart shown in FIG. 2 indicates the rotational speed of the carrier 54, that is, the engine rotational speed Ne. Also, the vertical axis on the right side of the alignment chart shown in FIG. 2 indicates the rotational speed of the ring gear 56, that is, the rotational speed Nm2 of the second MG 30. In addition, the direction of the arrow of each vertical axis | shaft of the alignment chart of FIG. 2 shows a normal rotation direction, and the direction opposite to the arrow direction shows a negative rotation direction.

  As an example, as indicated by the solid line in FIG. 2, the vehicle 1 has a rotation speed Nm1 of the first MG 20 of Nm1 (0), an engine rotation speed Ne of Ne (0), and a rotation of the second MG 30. Assume that the speed Nm2 is Nm2 (0).

  On the other hand, when the fuel injection to the engine 10 is stopped during traveling, the engine rotation speed Ne is reduced to zero. At this time, as indicated by a broken line in FIG. 2, the rotation speed Nm1 of the first MG 20 increases in the negative rotation direction from Nm1 (0) to Nm1 (1).

  It is assumed that the engine 10 is started using the first MG 20 when the vehicle 1 is traveling and the engine rotation speed Ne is zero. In this case, the engine 10 is cranked by raising the rotational speed Nm1 of the first MG 20 from Nm1 (1) (broken line in FIG. 2) to Nm1 (0) (solid line in FIG. 2), and the engine rotational speed Ne is increased.

  Returning to FIG. 1, the speed reducer 58 transmits the power from the power split device 40 and the second MG 30 to the drive wheels 80. Reducer 58 transmits the reaction force from the road surface received by drive wheels 80 to power split device 40 and second MG 30.

  PCU 60 converts the DC power stored in battery 70 into AC power for driving first MG 20 and second MG 30. PCU 60 includes a converter and an inverter (both not shown) controlled based on control signal S2 from ECU 200. The converter boosts the voltage of the DC power received from battery 70 and outputs it to the inverter. The inverter converts the DC power output from the converter into AC power and outputs the AC power to first MG 20 and / or second MG 30. Thus, first MG 20 and / or second MG 30 are driven using the electric power stored in battery 70. The inverter converts AC power generated by the first MG 20 and / or the second MG 30 into DC power and outputs the DC power to the converter. The converter steps down the voltage of the DC power output from the inverter and outputs the voltage to battery 70. Thereby, battery 70 is charged using the electric power generated by first MG 20 and / or second MG 30. The converter may be omitted.

  The battery 70 is a power storage device and is a rechargeable DC power source. As the battery 70, for example, a secondary battery such as nickel metal hydride or lithium ion is used. The voltage of the battery 70 is about 200V, for example. Battery 70 may be charged using electric power supplied from an external power source (not shown) in addition to being charged using electric power generated by first MG 20 and / or second MG 30 as described above. The battery 70 is not limited to a secondary battery, but may be a battery capable of generating a DC voltage, such as a capacitor, a solar battery, or a fuel battery.

  The battery 70 includes a battery temperature sensor 156 for detecting the battery temperature TB of the battery 70, a current sensor 158 for detecting the current IB of the battery 70, and a voltage sensor 160 for detecting the voltage VB of the battery 70. And are provided.

  Battery temperature sensor 156 transmits a signal indicating battery temperature TB to ECU 200. Current sensor 158 transmits a signal indicating current IB to ECU 200. Voltage sensor 160 transmits a signal indicating voltage VB to ECU 200.

  The start switch 150 is, for example, a push switch. The start switch 150 may be configured to insert a key into a key cylinder and rotate it to a predetermined position. Start switch 150 is connected to ECU 200. In response to the driver operating the start switch 150, the start switch 150 transmits a signal ST to the ECU 200.

  For example, when the signal ST is received when the system of the vehicle 1 is in a stopped state, the ECU 200 determines that an activation instruction has been received, and shifts the system of the vehicle 1 from the stopped state to the activated state. Further, when the signal ST is received when the system of the vehicle 1 is in the activated state, the ECU 200 determines that the stop instruction has been received, and shifts the system of the vehicle 1 from the activated state to the stopped state.

  The first resolver 12 detects the rotational speed Nm1 of the first MG 20. The first resolver 12 transmits a signal indicating the detected rotation speed Nm1 to the ECU 200. The second resolver 13 detects the rotational speed Nm2 of the second MG 30. The second resolver 13 transmits a signal indicating the detected rotation speed Nm2 to the ECU 200.

  The wheel speed sensor 14 detects the rotational speed Nw of the drive wheel 80. The wheel speed sensor 14 transmits a signal indicating the detected rotation speed Nw to the ECU 200. ECU 200 calculates vehicle speed V based on the received rotational speed Nw. ECU 200 may calculate vehicle speed V based on rotation speed Nm2 of second MG 30 instead of rotation speed Nw.

  Braking device 151 includes a brake actuator 152 and a disc brake 154. The disc brake 154 includes a brake disc that rotates integrally with the wheel, and a brake caliper that restricts rotation of the brake disc using hydraulic pressure. The brake caliper includes a brake pad provided so as to sandwich the brake disc in a direction parallel to the rotation shaft, and a wheel cylinder for transmitting hydraulic pressure to the brake pad. Based on the control signal S3 received from the ECU 200, the brake actuator 152 adjusts the hydraulic pressure generated when the driver depresses the brake pedal and the hydraulic pressure generated using a pump, a solenoid valve, and the like, and supplies the hydraulic pressure to the wheel cylinder. Adjust the hydraulic pressure. In FIG. 1, the braking device 151 is illustrated only on the right side of the rear wheel, but the braking device 151 is provided for each wheel.

  ECU 200 generates a control signal S1 for controlling engine 10, and outputs the generated control signal S1 to engine 10. ECU 200 also generates a control signal S2 for controlling PCU 60 and outputs the generated control signal S2 to PCU 60. Further, ECU 200 generates a control signal S3 for controlling brake actuator 152, and outputs the generated control signal S3 to brake actuator 152.

  The ECU 200 controls the entire hybrid system, that is, the charging / discharging state of the battery 70 and the operating states of the engine 10, the first MG 20 and the second MG 30 so that the vehicle 1 can operate most efficiently by controlling the engine 10, the PCU 60, and the like. .

  ECU 200 calculates a required driving force corresponding to the amount of depression of an accelerator pedal (not shown) provided in the driver's seat. ECU 200 determines the torque of first MG 20 and second MG 30 according to the calculated required driving force. And the output of the engine 10 is controlled.

  In the vehicle 1 having the above-described configuration, when only the second MG 30 is running when starting or running at a low speed and the efficiency of the engine 10 is poor. Further, during normal travel, for example, the power split device 40 divides the power of the engine 10 into two paths of power. The drive wheel 80 is directly driven by one power. The first MG 20 is driven with the other power to generate power. At this time, ECU 200 drives second MG 30 using the generated electric power. In this way, driving of the driving wheel 80 is performed by driving the second MG 30.

  Further, ECU 200 controls the output torque of second MG 30 in accordance with the output torque of engine 10, thereby executing vibration suppression control that cancels and reduces vibration caused by output torque of engine 10. For example, the output torque of second MG 30 is controlled so as to cancel the vibration according to the product of the output torque of engine 10 and a predetermined gain. In addition, since it is sufficient to use a known general technique for vibration suppression control, detailed description thereof will not be repeated here.

  When the vehicle 1 decelerates, the second MG 30 driven by the rotation of the drive wheels 80 functions as a generator to perform regenerative braking. The electric power recovered by regenerative braking is stored in the battery 70. ECU 200 increases the output of engine 10 to increase the first MG 20 when the remaining capacity of the power storage device (described in the following description as SOC (State of Charge)) decreases and charging is particularly necessary. Increase the amount of power generated by Thereby, the SOC of the battery 70 is increased. In addition, the ECU 200 may perform control to increase the driving force from the engine 10 as necessary even during low-speed traveling. For example, the battery 70 needs to be charged as described above, an auxiliary machine such as an air conditioner is driven, or the temperature of the cooling water of the engine 10 is raised to a predetermined temperature.

  When controlling the amount of charge and the amount of discharge of the battery 70, the ECU 200 determines the input power allowed when the battery 70 is charged based on the battery temperature TB and the current SOC (in the following description, “charging power upper limit value”). Output power (to be described as “discharge power upper limit value Wout” in the following description). For example, when the current SOC decreases, discharge power upper limit Wout is set to be gradually lower. On the other hand, when the current SOC increases, charging power upper limit value Win is set to gradually decrease.

  Further, the secondary battery used as the battery 70 has temperature dependency that the internal resistance increases at a low temperature. Further, at a high temperature, it is necessary to prevent the temperature from excessively rising due to further heat generation. For this reason, it is preferable to reduce each of the discharge power upper limit value Wout and the charge power upper limit value Win when the battery temperature TB is low and high. ECU 200 sets charge power upper limit value Win and discharge power upper limit value Wout by using, for example, a map or the like according to battery temperature TB and the current SOC.

  In the present embodiment, when engine 10 is started using first MG 20 while vehicle 1 is traveling, the torque of first MG 20 is limited so that the power generated by first MG 20 is smaller than charging power upper limit Win. Is done.

  With reference to FIG. 3, the process performed by ECU 200 mounted on vehicle 1 according to the present embodiment will be described. The processing described below may be executed by software, may be executed by hardware, or may be executed by cooperation of software and hardware.

  In step (hereinafter, step is described as S) 100, ECU 200 determines whether engine 10 is being started, specifically, whether engine 10 is being cranked by first MG 20 or not. Determine. If the starting process is being executed (YES in S100), in S102, ECU 200 determines whether or not rotation speed Ne of engine 10 is equal to or greater than a predetermined threshold value. By determining whether or not the rotational speed Ne of the engine 10 is equal to or higher than a predetermined threshold value, it is determined whether or not the engine 10 is before the first explosion.

  If it is before the first explosion (YES in S102), a predetermined gain G1 is used in vibration suppression control in S104. That is, the gain G1 is used during the period from cranking to the first explosion. If it is after the first explosion (NO in S102), a predetermined gain G2 different from gain G1 is used in S106. For example, the gain G2 is smaller than the gain G1.

  If the engine 10 is not being started (NO in S100), a predetermined gain G3 different from gain G1 and gain G2 is used in S108. An appropriate value may be used as the gain G3 according to the driving state of the vehicle.

  As described above, according to the present embodiment, the gain used in the vibration suppression control is relative to each of the period from the cranking of engine 10 to the first explosion and the period after the first explosion. Appropriately determined. For example, the gain is increased during the period up to the first explosion when large vibrations can occur, while the gain is decreased during the period after the first explosion when large vibrations are unlikely to occur. Thereby, while the vibration is effectively reduced in the period before the first explosion, the sound that can be generated due to the vibration suppression control can be reduced in the period after the first explosion.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Vehicle, 10 Engine, 11 Engine rotational speed sensor, 12 1st resolver, 13 2nd resolver, 14 Wheel speed sensor, 16 Drive shaft, 20 1st motor generator, 30 2nd motor generator, 40 Power split device, 50 Sun gear , 52 pinion gear, 54 carrier, 56 ring gear, 58 speed reducer, 70 battery, 80 drive wheel, 102 cylinder, 104 fuel injection device, 150 start switch, 156 battery temperature sensor, 158 current sensor, 160 voltage sensor, 200 ECU.

Claims (1)

Vibration suppression control means for outputting torque for reducing vibration caused by torque output from the engine;
A vehicle vibration damping control device comprising: a changing means for changing a gain used in the vibration damping control means between a period from cranking the engine to a first explosion and a period after the first explosion.

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