JP2013132945A - Control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the control device of a hybrid vehicle preventing occurrence of abnormal sound in a power transmission system and effectively using driving force of an internal combustion engine operated for preventing the occurrence of the abnormal sound.SOLUTION: When an engine is driven at a low vehicle speed (YES-determination by ST1), and when the vehicle speed is within a predetermined range (YES-determination by ST4), a P-charge amount is set high, and the P-charge amount is adjusted according to the vehicle speed (ST6). Meanwhile, when the vehicle speed is out of the predetermined range, the P-charge amount is set low (ST5). Thereby, when the vehicle speed is within the predetermined range, the engine can be driven efficiently while suppressing the occurrence rattling noises. Furthermore, when the vehicle speed is out of the predetermined range, the engine is quickly stopped thereafter, to reduce the amount of fuel consumption.

Description

  The present invention relates to a control device for a hybrid vehicle in which an internal combustion engine and an electric motor are mounted as a driving force source. In particular, the present invention relates to an improvement in control for reducing or preventing abnormal noise generated in a power transmission system.

  In recent years, from the viewpoint of environmental protection, reduction of exhaust gas emissions from internal combustion engines mounted on vehicles (hereinafter sometimes referred to as “engines”) and improvement of fuel consumption rate (fuel consumption) have been desired. Hybrid vehicles equipped with a hybrid system have been put to practical use as vehicles satisfying these requirements.

  The hybrid vehicle includes an engine such as a gasoline engine or a diesel engine, and an electric motor (for example, a motor generator or a motor) that is driven by electric power generated by the output of the engine or electric power stored in a battery (power storage device). The vehicle travels while using one or both of these engines and electric motors as a driving force source.

  As a power train employed in this type of hybrid vehicle, an engine, first and second electric motors (motor generators), and a power split mechanism are configured as disclosed in Patent Documents 1 to 3 below. One having a planetary gear mechanism is known. Specifically, the engine crankshaft is connected to the planetary carrier of the power split mechanism, the first electric motor (first motor generator MG1) is connected to the sun gear, and the reduction gear (for example, a planetary gear mechanism) is configured to the ring gear. ) Is connected to the second electric motor (second motor generator MG2). The drive gear is connected to the ring gear through a reduction mechanism and a differential gear so that power can be transmitted.

  Thus, during normal travel, the driving force (torque) input from the engine to the planetary carrier is divided (torque divided) into the ring gear (drive wheel side) and the sun gear (first electric motor side). The torque divided on the ring gear side drives the drive wheels as direct torque (torque transmitted directly from the engine to the drive wheels). On the other hand, the torque divided on the sun gear side is transmitted to the first electric motor, which generates electric power. As a result, the second electric motor is driven by the electric power obtained (torque is generated), and assist torque for the drive wheels is obtained.

  Thus, the power split mechanism functions as a differential mechanism, and by the differential action, the main part of the power from the engine is mechanically transmitted to the drive wheels, and the remaining part of the power from the engine is transferred to the first electric motor. The function as a transmission (electric continuously variable transmission) in which the transmission gear ratio is electrically changed is exhibited by electrically transmitting the motor to the second electric motor using an electric path. . As a result, it is possible to obtain the engine operating state in which the fuel consumption rate is optimized while obtaining the driving force required for the driving wheels.

  Further, in a region where the engine efficiency is low, such as when the vehicle is starting or running at a low speed, the engine is stopped and the drive wheels are driven by the power of only the second electric motor.

  By the way, in the hybrid vehicle described above, there is a possibility that abnormal noise is generated in the power transmission system in a certain driving state. For example, when the vehicle is running at a low speed, such as in a traffic jam, when the driving wheel is driven by the power of only the second electric motor and the torque command value is low, the rotor of the second electric motor is used for the ring gear. In the power transmission path (eg, the reduction mechanism) up to this point, a so-called rattling noise (also referred to as “gull noise”) is generated due to the presence of rattling (backlash, etc.) between the gears. there is a possibility.

  In order to prevent the occurrence of such abnormal noise (gap sound), when the operating condition for generating the abnormal noise is satisfied (for example, when the torque command value of the second motor is within a predetermined range). An engine is started, for example, is operated at idling speed, and the backlash between the gears is reduced to one side using the engine torque (for example, Patent Document 1 below).

JP 11-93725 A JP 2008-126809 A JP 2010-89543 A

  However, since the technical idea of the conventional noise prevention operation described above is to operate the engine only for noise prevention, the fuel consumed for the engine operation (idling operation) is wasted. Since the idling operation state of the engine is an operation state with relatively low efficiency, if such a state is continued for a long period of time, there is a limit in improving the fuel consumption rate. become.

  The present invention has been made in view of the above points, and an object of the present invention is to prevent the occurrence of abnormal noise in the power transmission system and to operate the internal combustion engine that is operated to prevent the occurrence of this abnormal noise. An object of the present invention is to provide a control device for a hybrid vehicle that can effectively use the driving force of the engine.

-Summary of invention-
The outline of the present invention taken in order to achieve the above object is that the power generation amount of the generator using the driving force of the engine is increased when the driving condition of abnormal power is generated in the power transmission system of the hybrid vehicle. Thus, the engine output is increased and the engine is operated in a high efficiency region. As a result, the generation of abnormal noise is suppressed, and the output of the engine that is driven to suppress the generation of abnormal noise is effectively utilized.

-Solution-
Specifically, the present invention includes an internal combustion engine capable of outputting power for traveling and an electric motor capable of outputting power for traveling, and travels using at least one of the internal combustion engine and the motor as a travel driving force source. A control apparatus for a hybrid vehicle that drives the internal combustion engine when abnormal noise occurs in a power transmission path at low vehicle speeds when the electric motor is used as a driving force source is assumed. When the vehicle speed is outside the predetermined range with respect to the control device for the hybrid vehicle, when the vehicle speed is within a predetermined range at the low vehicle speed, the amount of power generated by using the driving force of the internal combustion engine. It is set as the structure which sets more.

  Due to this specific matter, when the vehicle speed is within a predetermined range at a low vehicle speed when the electric motor is used as a driving force source, the idling operation in which the efficiency of the internal combustion engine is conventionally low is included in the present solution. Therefore, a large amount of power generation using the driving force of the internal combustion engine is set to increase the output of the internal combustion engine. For this reason, the internal combustion engine can be operated in a highly efficient region. For this reason, the internal combustion engine can be operated efficiently while suppressing the generation of abnormal noise, and the amount of power stored in the power storage device can be increased. In addition, when the vehicle speed is outside the predetermined range, the power generation amount using the driving force of the internal combustion engine is set to be small, and then the internal combustion engine can be stopped quickly to reduce fuel consumption. To be able to.

  More specifically, the case where the vehicle speed is within the predetermined range is a case where a rattling sound may be generated due to a collision between gears existing in the power transmission path.

  Thus, only when a rattling noise (abnormal noise) is generated, the above-described control for setting a large amount of power generation is performed, so that the internal combustion engine is not operated at a higher output than necessary. As a result, the fuel consumption rate can be improved, and overcharging of the power storage device can be prevented.

  Further, in an operating state in which a large amount of power generation is performed using the driving force of the internal combustion engine, when the vehicle speed is out of the predetermined range, power generation is performed using the driving force of the internal combustion engine. The amount is set to be small, and the internal combustion engine stop process is started.

  Also in this case, the internal combustion engine can be quickly stopped in response to the request to stop the internal combustion engine, and the fuel consumption can be reduced.

  Further, the power transmission system is provided with two generator motors, and the other generator motor uses the driving force of the internal combustion engine to generate power while driving power is output from one generator motor. Yes.

  This is a case where the present invention is applied to a so-called two-motor type hybrid vehicle, and power is generated by the other generator motor while the vehicle is driven by power from one generator motor.

  In the present invention, in the hybrid vehicle, when the vehicle speed is within a predetermined range at a low vehicle speed, a large amount of power generation using the driving force of the internal combustion engine is set. As a result, the internal combustion engine can be efficiently operated while suppressing the generation of abnormal noise, and the charging efficiency can be improved.

It is a figure showing a schematic structure of a hybrid vehicle concerning an embodiment. It is a block diagram which shows schematic structure of a control system. It is a figure for demonstrating the operating point of an engine. It is a flowchart figure which shows the procedure of noise reduction control. It is a figure which shows an example of the P charge amount setting map for setting P charge amount according to a vehicle speed. It is a figure which shows the change of the vehicle speed, engine speed, intermittent operation prohibition flag, and engine output at the time of execution of noise reduction control.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a case where the present invention is applied to an FF (front engine / front drive) type hybrid vehicle will be described.

  FIG. 1 is a diagram showing a schematic configuration of a hybrid vehicle 1 according to the present embodiment. As shown in FIG. 1, a hybrid vehicle 1 has a damper 2b on an engine 2 and a crankshaft 2a as an output shaft of the engine 2 as a drive system for applying a driving force to front wheels (drive wheels) 6a and 6b. A three-shaft power split mechanism 3 connected via the power split mechanism, a first motor generator MG1 capable of generating power connected to the power split mechanism 3, and a ring gear shaft 3e as a drive shaft connected to the power split mechanism 3. And a second motor generator MG2 connected via a reduction mechanism 7. The crankshaft 2a, power split mechanism 3, first motor generator MG1, second motor generator MG2, reduction mechanism 7 and ring gear shaft 3e constitute a power transmission system.

  The ring gear shaft 3e is connected to the front wheels 6a and 6b via a gear mechanism 4 and a differential gear 5 for the front wheels.

  The hybrid vehicle 1 also includes a hybrid electronic control unit (hereinafter referred to as a hybrid ECU (Electronic Control Unit)) 10 that controls the entire drive system of the vehicle.

-Engine and engine ECU-
The engine 2 is an internal combustion engine that outputs power using a hydrocarbon-based fuel such as gasoline or light oil, and an engine electronic control unit (hereinafter referred to as an engine ECU) that receives signals from various sensors that detect the operating state of the engine 2. ) 11 performs operation control such as fuel injection control, ignition control, intake air amount adjustment control, and the like.

  The engine ECU 11 communicates with the hybrid ECU 10, controls the operation of the engine 2 based on a control signal from the hybrid ECU 10, and outputs data related to the operating state of the engine 2 to the hybrid ECU 10 as necessary. The engine ECU 11 is connected to a crank position sensor 56, a water temperature sensor 57, and the like. The crank position sensor 56 outputs a detection signal (pulse) every time the crankshaft 2a rotates by a certain angle. Based on the output signal from the crank position sensor 56, the engine ECU 11 calculates the engine speed Ne. The water temperature sensor 57 outputs a detection signal corresponding to the coolant temperature of the engine 2.

-Power split mechanism-
As shown in FIG. 1, the power split mechanism 3 includes a sun gear 3a as an external gear, a ring gear 3b as an internal gear arranged concentrically with the sun gear 3a, a plurality of gears meshed with the sun gear 3a and meshed with the ring gear 3b. A planetary gear mechanism 3d that includes a pinion gear 3c and a planetary carrier 3d that holds the plurality of pinion gears 3c so as to rotate and revolve is configured as a planetary gear mechanism that performs differential action with the sun gear 3a, the ring gear 3b, and the planetary carrier 3d as rotational elements. Yes. In the power split mechanism 3, the crankshaft 2a of the engine 2 is coupled to the planetary carrier 3d. Further, the rotor (rotor) of the first motor generator MG1 is connected to the sun gear 3a. Further, the reduction mechanism 7 is connected to the ring gear 3b via the ring gear shaft 3e.

  In the power split mechanism 3 configured as described above, when the reaction torque generated by the first motor generator MG1 is input to the sun gear 3a with respect to the output torque of the engine 2 input to the planetary carrier 3d, the output element A torque larger than the torque input from the engine 2 appears in a certain ring gear 3b. In this case, the first motor generator MG1 functions as a generator. When first motor generator MG1 functions as a generator, the driving force of engine 2 input from planetary carrier 3d is distributed according to the gear ratio between sun gear 3a and ring gear 3b.

  On the other hand, when the engine 2 is requested to start, the first motor generator MG1 functions as an electric motor (starter motor), and the driving force of the first motor generator MG1 is applied to the crankshaft 2a via the sun gear 3a and the planetary carrier 3d. Given, the engine 2 is cranked.

  Further, in the power split mechanism 3, when the rotational speed of the ring gear 3b (output shaft rotational speed) is constant, the rotational speed of the engine 2 is continuously increased by changing the rotational speed of the first motor generator MG1 up and down. Can be changed (infinitely). That is, the power split mechanism 3 functions as a transmission unit.

-Reduction mechanism-
As shown in FIG. 1, the reduction mechanism 7 includes a sun gear 7a as an external gear, a ring gear 7b as an internal gear arranged concentrically with the sun gear 7a, and a plurality of gears meshed with the sun gear 7a and meshed with the ring gear 7b. A pinion gear 7c and a planetary carrier 7d that holds the plurality of pinion gears 7c so as to rotate freely are provided. In the reduction mechanism 7, the planetary carrier 7d is fixed to the transmission case. Sun gear 7a is coupled to the rotor (rotor) of second motor generator MG2. Further, the ring gear 7b is connected to the ring gear shaft 3e.

-Power switch-
The hybrid vehicle 1 is provided with a power switch 51 (see FIG. 2) for switching between starting and stopping of the hybrid system. The power switch 51 is, for example, a rebound push switch, and the switch On and the switch Off are alternately switched every time the pressing operation is performed.

  Here, the hybrid system uses the engine 2 and the motor generators MG1 and MG2 as driving power sources for traveling, and controls the operation of the engine 2, the drive control of the motor generators MG1 and MG2, and the engine 2 and the motor generators MG1 and MG2. This is a system that controls the traveling of the hybrid vehicle 1 by executing various controls including cooperative control.

  When the power switch 51 is operated by a passenger including a driver, the power switch 51 outputs a signal (IG-On command signal or IG-Off command signal) corresponding to the operation to the hybrid ECU 10. The hybrid ECU 10 starts or stops the hybrid system based on the signal output from the power switch 51 and the like.

  Specifically, when the power switch 51 is operated while the hybrid vehicle 1 is stopped, the hybrid ECU 10 activates the hybrid system at a P position described later. As a result, the vehicle can run. Since the hybrid system is activated at the P position when the hybrid system is stopped, no driving force is output even in the accelerator-on state. The state in which the vehicle can travel is a state in which the vehicle traveling can be controlled by a command signal from the hybrid ECU 10, and the hybrid vehicle 1 can start and travel (Ready-On state) if the driver turns on the accelerator. is there. The Ready-On state includes a state where the engine 2 is stopped and the second motor generator MG2 can start and travel the hybrid vehicle 1 (a state where EV traveling is possible).

  The hybrid ECU 10 stops the hybrid system when the power switch 51 is operated (for example, short-pressed), for example, when the hybrid system is activated and is in the P position when the vehicle is stopped.

-Motor generator and motor ECU-
Each of motor generators MG1 and MG2 is configured by a known synchronous generator motor that can be driven as a generator and driven as an electric motor, and is connected to battery (power storage device) 24 via inverters 21 and 22 and boost converter 23. Power is exchanged between them. A power line 25 that connects inverters 21 and 22, boost converter 23, and battery 24 to each other is configured as a positive bus and a negative bus that are shared by inverters 21 and 22. Electric power is generated by either motor generator MG 1 or MG 2. The electric power generated can be consumed by other motors. Therefore, battery 24 is charged / discharged by electric power generated from one of motor generators MG1 and MG2 or insufficient electric power. Note that when the power balance is balanced by motor generators MG1 and MG2, battery 24 is not charged or discharged.

  Both motor generators MG1 and MG2 are driven and controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 13. The motor ECU 13 includes signals necessary for driving and controlling the motor generators MG1 and MG2, for example, an MG1 rotational speed sensor (resolver) 26 and MG2 for detecting the rotational positions of the rotors (rotating shafts) of the motor generators MG1 and MG2. A signal from rotation speed sensor 27, a phase current applied to motor generators MG1 and MG2 detected by a current sensor, and the like are input. Further, the motor ECU 13 outputs a switching control signal to the inverters 21 and 22. For example, drive control (for example, regenerative control of the second motor generator MG2) is performed using one of the motor generators MG1, MG2 as a generator, or drive control (for example, power running control of the second motor generator MG2) is performed as an electric motor. . Further, the motor ECU 13 communicates with the hybrid ECU 10, and controls the motor generators MG1 and MG2 as described above according to the control signal from the hybrid ECU 10, and also operates the motor generators MG1 and MG2 as necessary. Is output to the hybrid ECU 10.

-Battery and battery ECU-
The battery 24 is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 14. The battery ECU 14 receives signals necessary for managing the battery 24, for example, a voltage between terminals from a voltage sensor 24 a installed between terminals of the battery 24, and a power line 25 connected to an output terminal of the battery 24. The charging / discharging current from the attached current sensor 24b, the battery temperature Tb from the battery temperature sensor 24c attached to the battery 24, and the like are input, and data regarding the state of the battery 24 is communicated to the hybrid ECU 10 as necessary. Output.

  Further, in order to manage the battery 24, the battery ECU 14 calculates a remaining power SOC (State of Charge) based on the integrated value of the charge / discharge current detected by the current sensor 24b, and calculates the calculated value. Based on the remaining capacity SOC and the battery temperature Tb detected by the battery temperature sensor 24c, an input limit Win and an output limit Wout that are the maximum allowable power that may charge / discharge the battery 24 are calculated. The input limit Win and the output limit Wout of the battery 24 set basic values of the input limit Win and the output limit Wout based on the battery temperature Tb, and the input limit correction coefficient and the output based on the remaining capacity SOC of the battery 24. A limiting correction coefficient can be set, and the basic value of the set input limit Win and output limit Wout can be multiplied by the correction coefficient.

-Hybrid ECU and control system-
As shown in FIG. 2, the hybrid ECU 10 includes a CPU (Central Processing Unit) 40, a ROM (Read Only Memory) 41, a RAM (Random Access Memory) 42, a backup RAM 43, and the like. The ROM 41 stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU 40 executes various arithmetic processes based on various control programs and maps stored in the ROM 41. The RAM 42 is a memory that temporarily stores calculation results in the CPU 40, data input from each sensor, and the like. The backup RAM 43 is a non-volatile memory that stores data to be saved at the time of IG-Off, for example.

  The CPU 40, the ROM 41, the RAM 42, and the backup RAM 43 are connected to each other via the bus 46, and are also connected to the input interface 44 and the output interface 45.

  The input interface 44 includes a shift position sensor 50 that detects an operation position and the like of a shift lever 61 of a shift operation device 60, which will be described later, the power switch 51, and an accelerator opening sensor 52 that outputs a signal corresponding to the depression amount of an accelerator pedal. A brake pedal sensor 53 for outputting a signal corresponding to the depression amount of the brake pedal, a vehicle speed sensor 54 for outputting a signal corresponding to the vehicle body speed, and the like are connected.

  Thus, the hybrid ECU 10 receives the shift position signal from the shift position sensor 50, the IG-On signal and the IG-Off signal from the power switch 51, the accelerator opening signal from the accelerator opening sensor 52, and the brake pedal sensor 53. The brake pedal position signal, the vehicle speed signal from the vehicle speed sensor 54, and the like are input.

  Here, the shift operation device 60 will be briefly described. As shown in FIG. 2, the shift operation device 60 includes a shift lever (also referred to as a shift knob) 61 that is disposed in the vicinity of the driver's seat and can be displaced, and a P switch 62 that can be pushed. . The shift lever 61 includes a drive range (D range) for forward travel, a brake range (B range) for forward travel where the braking force (engine brake) when the accelerator is off is increased, and a reverse range (R range) for reverse travel. A neutral range (N range) is set, and the driver can displace the shift lever 61 to a desired range. These positions of the D range, B range, R range, and N range are detected by the shift position sensor 50. An output signal of the shift position sensor 50 is input to the hybrid ECU 10. Further, the P switch 62 sets a parking position (P position) by a driver's pushing operation, and a pushing signal of the P switch 62 is also detected by the shift position sensor 50. As the P switch 62 is pushed in, a parking ECU (not shown) receives a command signal from the hybrid ECU 10, and the parking lock mechanism is activated to indirectly lock the front wheels 6a and 6b.

  On the other hand, the input interface 44 and the output interface 45 are connected to the engine ECU 11, the motor ECU 13, the battery ECU 14, and the like. The hybrid ECU 10 receives various control signals and data between the engine ECU 11, the motor ECU 13, and the battery ECU 14. Sending and receiving.

  The hybrid ECU 10 performs various controls of the engine 2 including throttle opening control (intake air amount control), fuel injection amount control, ignition timing control, etc. of the engine 2 based on the output signals of the various sensors described above. To do. The hybrid ECU 10 also executes “abnormal noise reduction control” to be described later.

-Flow of driving force in hybrid system-
The hybrid vehicle 1 configured as described above calculates the torque (requested torque) to be output to the drive wheels 6a and 6b based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal by the driver. The engine 2 and the motor generators MG1 and MG2 are controlled to run with the required driving force corresponding to the required torque. Specifically, in order to reduce fuel consumption, the required driving force is obtained by using the second motor generator MG2 in an operating region where the required driving force is relatively low. On the other hand, in an operation region where the required driving force is relatively high, the second motor generator MG2 is used and the engine 2 is driven, and the driving force from these driving force sources (traveling driving force source) is used to generate the request. The driving force should be obtained.

  More specifically, when the driving efficiency of the engine 2 is low, such as when the vehicle starts or travels at a low speed, the vehicle travels only with the second motor generator MG2 (hereinafter also referred to as “EV travel”). Further, EV driving is also performed when the driver selects the EV driving mode with a driving mode selection switch arranged in the vehicle interior.

  On the other hand, during normal traveling (hereinafter also referred to as HV traveling), for example, the power split mechanism 3 divides the driving force of the engine 2 into two paths, and the one driving force directly drives the driving wheels 6a and 6b (by direct torque). Drive), and the first motor generator MG1 is driven by the other driving force to generate electric power. At this time, the second motor generator MG2 is driven with electric power generated by driving the first motor generator MG1 to assist driving of the driving wheels 6a and 6b (driving by an electric path).

  In this way, the power split mechanism 3 functions as a differential mechanism, and the main part of the power from the engine 2 is mechanically transmitted to the drive wheels 6a and 6b by the differential action, and the power from the engine 2 is transmitted. The remaining portion is electrically transmitted using an electric path from the first motor generator MG1 to the second motor generator MG2, thereby exhibiting a function as an electric continuously variable transmission in which the gear ratio is electrically changed. . As a result, the engine rotation speed and the engine torque can be freely operated without depending on the rotation speed and torque of the drive wheels 6a and 6b (ring gear shaft 3e), and the drive required for the drive wheels 6a and 6b. While obtaining power, it is possible to obtain the operating state of the engine 2 (the operating state on the optimum fuel efficiency operation line described later) in which the fuel consumption rate is optimized.

  This will be specifically described with reference to FIG. FIG. 3 is a diagram showing the operating point of the engine 2 with the horizontal axis as the engine rotation speed and the vertical axis as the engine torque. The solid line in the figure is the optimum fuel consumption operation line, and the engine 2 can be controlled to the operating state on this optimum fuel consumption operation line by the electric speed change function using the power split mechanism 3 described above. Yes. Specifically, the intersection (point A in the figure) of the required power line (a line indicated by a two-dot chain line in the figure) determined according to the accelerator opening and the like and the optimum fuel efficiency operation line is determined by the engine 2. The hybrid system is controlled as a target operating point (target operating point).

  Further, during high speed traveling, the electric power from the battery 24 is further supplied to the second motor generator MG2, and the output of the second motor generator MG2 is increased to add driving force to the driving wheels 6a and 6b (driving force assist). Power running).

  Furthermore, at the time of deceleration, the second motor generator MG2 functions as a generator to perform regenerative power generation, and the recovered power is stored in the battery 24. When the amount of charge (the remaining capacity; SOC) of the battery 24 is reduced and charging is particularly necessary, the output of the engine 2 is increased to increase the amount of power generated by the first motor generator MG1 to charge the battery 24. Increase the amount. Further, there is a case where control is performed to increase the output of the engine 2 as necessary even during low-speed traveling. For example, it is necessary to charge the battery 24 as described above, to drive an auxiliary machine such as an air conditioner, or to raise the temperature of the cooling water of the engine 2 to a predetermined temperature.

  Further, in the hybrid vehicle 1 of the present embodiment, the engine 2 is stopped in order to improve fuel efficiency depending on the driving state of the vehicle and the state of the battery 24. And after that, the driving | running state of the hybrid vehicle 1 and the state of the battery 24 are detected, and the engine 2 is restarted. Thus, in the hybrid vehicle 1, even if the power switch 51 is in the ON position, the engine 2 is intermittently operated (operation that repeats engine stop and restart).

-Noise reduction control-
Next, the abnormal noise reduction control that is a feature of the present embodiment will be specifically described. The rotor of the second motor generator MG2 is used when the driving wheels 6a and 6b are driven by the power of only the second motor generator MG2 and the torque command value is low, for example, during low speed running such as traffic jams. In the power transmission path (for example, the reduction mechanism 7) from the ring gear shaft 3e to the ring gear shaft 3e, rattling noise (rattle noise) is generated due to the presence of backlash (backlash, etc.) between the gears. there's a possibility that.

  For this reason, in the present embodiment, when an operation state in which the rattling noise may occur is generated, the engine 2 is started, and the backlash between the gears of the reduction mechanism 7 is reduced on one side using the engine torque. This prevents the generation of rattling noise. Furthermore, in this embodiment, as the control of the engine 2 at this time, when the vehicle speed is within a predetermined range, the target value of the charge amount to the battery 24 (the power generation by the first motor generator MG1 by the driving force of the engine 2). The target power amount when performing the engine (hereinafter, sometimes referred to as “P charge amount”) is set high, thereby increasing the required power for the engine 2 and preventing the occurrence of the rattling noise. 2 is operated in a high-efficiency operation region (operating in a high-efficiency operation region compared to idling operation; low-load operation), and the amount of charge to the battery 24 is increased.

  Next, a specific operation procedure of the noise reduction control will be described with reference to the flowchart of FIG. This flowchart is executed, for example, every predetermined time (several msec) after the power switch 51 is turned on.

  First, in step ST1, it is determined whether or not the traveling state of the hybrid vehicle 1 is a low vehicle speed state and the engine 2 is being driven. The determination that the traveling state is a low vehicle speed state is made based on an output signal from the vehicle speed sensor 54. Further, it is determined that the engine 2 is driven based on an output signal from the crank position sensor 56. Further, it may be determined that the engine 2 is driven by recognizing that an engine drive command signal is transmitted from the hybrid ECU 10 or the engine ECU 11.

  Here, the low vehicle speed state includes, for example, a state of 25 km / h or less. Further, as described above, the engine 2 is not normally driven in the low vehicle speed state, but it is determined in this step ST1 that the engine 2 is driven by some driving request. For example, when the remaining capacity SOC of the battery 24 is equal to or less than a predetermined amount, when there is a drive request for the engine 2 due to the operation of auxiliary equipment (for example, an air conditioner), The case where there is a drive request of 2 is mentioned.

  If the running state of the hybrid vehicle 1 is not a low vehicle speed state or if the engine 2 is stopped, a NO determination is made in step ST1, and the process proceeds to step ST2, where the intermittent operation of the engine 2 (engine stop if necessary) And the operation in which restarting is repeated). For example, operation control is performed such that the engine 2 is stopped when the vehicle is stopped or when traveling at a low speed, and the engine 2 is driven when traveling at a high speed or when the load is high.

  On the other hand, when the traveling state of the hybrid vehicle 1 is the low vehicle speed state and the engine 2 is driven, a YES determination is made in step ST1, and the process proceeds to step ST3. In this step ST3, it is determined whether or not an intermittent operation prohibition flag that is turned on when the operation state needs to prevent the generation of the rattling sound is ON. This intermittent operation prohibition flag is a power transmission path between the rotor of the second motor generator MG2 and the ring gear shaft 3e when the command torque for the second motor generator MG2 is a predetermined value or less (for example, 20 Nm or less). Is turned on because there is a possibility that a gear rattling sound (rattle noise) may occur.

  For example, when the command torque for the second motor generator MG2 exceeds a predetermined value and the intermittent operation prohibition flag is OFF, and when NO is determined in step ST3, the process proceeds to step ST2, and Intermittent operation is performed. In this case, the determination of YES in step ST1 is that the remaining capacity SOC of the battery 24 is equal to or less than a predetermined amount or that there is a drive request for the engine 2 due to the operation of the auxiliary machinery. Therefore, it can be determined that there is no request for driving the engine 2 for suppressing the above-mentioned rattling noise. That is, the intermittent operation is performed as necessary on the assumption that engine control for suppressing a rattling noise is not necessary. That is, the engine 2 is stopped when the remaining capacity SOC of the battery 24 exceeds a predetermined amount or when the operation of the auxiliary machinery is stopped.

  On the other hand, if the command torque for the second motor generator MG2 is equal to or less than a predetermined value, and the intermittent operation prohibition flag is ON, and YES is determined in step ST3, the process proceeds to step ST4, and It is determined whether or not the current vehicle speed recognized based on the output signal from the vehicle speed sensor 54 is within a predetermined range, that is, exceeds the vehicle speed A and falls below the vehicle speed B. Examples of the vehicle speed A include 1 km / h, and examples of the vehicle speed B include 20 km / h. These values are not limited to this, and are set by measuring the range of the vehicle speed at which a rattling sound is generated in advance through experiments and simulations.

  If the current vehicle speed is out of the predetermined range and NO is determined in step ST4, the process proceeds to step ST5, the P charge amount is set low, and the intermittent operation control is enabled. That is, when the output of the engine 2 is reduced by setting the P charge amount low (for example, the fuel injection amount from the injector is reduced, etc.) and the intermittent operation prohibition flag is turned OFF. The engine 2 can be stopped immediately.

  On the other hand, if the current vehicle speed is in the predetermined range and YES is determined in step ST4, the process proceeds to step ST6 and the P charge amount is set high. Specifically, the P charge amount is adjusted according to the vehicle speed. As a result, the required power for the engine 2 is increased (for example, the throttle valve opening is increased and the fuel injection amount from the injector is increased; an operating state equivalent to low-load operation), and the pressing torque applied to each gear by the engine 2 Is increased to prevent the generation of rattling noise, and the engine 2 is operated in a highly efficient operation region (low load operation region) to increase the amount of charge to the battery 24. In this case, various control parameters of the engine 2 for increasing the output in accordance with the P charge amount include various parameters such as the engine speed, the throttle valve opening, and the fuel injection amount.

  FIG. 5 is a P charge amount setting map referred to when setting the P charge amount in step ST6. This P charge amount setting map is stored in the ROM 41, and in the range from the vehicle speed A to the vehicle speed B, the higher the vehicle speed, the larger the P charge amount is set. The relationship between the vehicle speed and the P charge amount is not limited to this, and is set in advance through experiments and simulations so that the generation of rattling noise can be prevented and the engine 2 can be operated in a highly efficient driving range. Is done.

  The above operation is repeatedly executed.

  FIG. 6 is a diagram illustrating changes in the vehicle speed, the engine rotation speed, the intermittent operation prohibition flag, and the engine output when the abnormal noise reduction control described above is executed. In this figure, the alternate long and short dash line of the engine output indicates a change in the conventional engine output (the idling operation is performed during the noise reduction control).

  In the low vehicle speed traveling state where the second motor generator MG2 is the driving force source, when the vehicle speed reaches the predetermined range at the timing t1 in the figure, the P charge amount is set high, thereby increasing the engine output. Along with this, the engine speed has also increased. Thereafter, the intermittent operation prohibition flag is turned ON at timing t2, and the intermittent operation of the engine 2 is prohibited. That is, the operation of the engine 2 for suppressing the rattling noise is continued. In the period from timing t1 to timing t3 in the figure, the P charge amount is set high, and the engine 2 can be operated in a highly efficient region by increasing the output of the engine 2. For this reason, the engine 2 can be efficiently operated while suppressing the generation of abnormal noise. Thereafter, when the vehicle speed starts to decrease (timing t3), the P charge amount is set low, and the engine output decreases accordingly. When the vehicle speed reaches a predetermined value (timing t4), the intermittent operation prohibition flag is turned off, and the intermittent operation of the engine 2 is permitted. Thereafter, at timing t5, the engine 2 is stopped, and the traveling state using the second motor generator MG2 as a driving force source is restored.

  As described above, in the present embodiment, when the vehicle speed is within a predetermined range (A <vehicle speed <B) at a low vehicle speed when traveling using the second motor generator MG2 as a travel driving force source, the conventional engine The engine 2 is operated in a high-efficiency region by setting a large amount of P-charge, which is the amount of power generation that uses the driving force of the engine 2, and increasing the output of the engine 2, which was an idling operation with low efficiency. It becomes possible to make it. For this reason, the engine 2 can be efficiently operated while suppressing the generation of abnormal noise. In addition, when the vehicle speed is out of the predetermined range, the P charge amount is set to a small value, and then the engine 2 can be quickly stopped, so that the fuel consumption can be reduced.

  Further, only when the condition (vehicle speed) for generating a rattling sound is reached, the P charge amount is set to be large, so that the engine 2 is not operated at a higher output than necessary. As a result, the fuel consumption rate can be improved, and overcharging of the battery 24 can be prevented.

-Other embodiments-
In the embodiment described above, the example in which the present invention is applied to the control of the FF (front engine / front drive) type hybrid vehicle has been described. However, the present invention is not limited to this, and the FR (front engine / rear drive) is not limited thereto. ) Type hybrid vehicle and four-wheel drive type hybrid vehicle.

  In the above-described embodiment, an example in which the present invention is applied to control of a hybrid vehicle on which two generator motors of the first motor generator MG1 and the second motor generator MG2 are mounted has been described. However, one generator motor is mounted. The present invention can also be applied to control of hybrid vehicles and hybrid vehicles equipped with three or more generator motors.

  INDUSTRIAL APPLICABILITY The present invention can be applied to noise reduction control that starts an internal combustion engine when noise occurs in a hybrid vehicle equipped with an internal combustion engine and an electric motor.

1 Hybrid vehicle 2 Engine (internal combustion engine)
3 Power split mechanism 3e Ring gear shaft 7 Reduction mechanism 7a Sun gear 7b Ring gear 7c Pinion gear 7d Planetary carrier 54 Vehicle speed sensor MG1 First motor generator (generator motor)
MG2 Second motor generator (generator motor)

Claims (4)

An internal combustion engine capable of outputting traveling power and an electric motor capable of outputting traveling power are provided, the vehicle is driven using at least one of the internal combustion engine and the motor as a driving force source, and the electric motor is used as a driving force source. In a control device for a hybrid vehicle that drives the internal combustion engine when abnormal noise occurs in the power transmission path at low vehicle speeds traveling as
When the vehicle speed is within a predetermined range at the low vehicle speed, the power generation amount that generates power using the driving force of the internal combustion engine is set to be larger than that when the vehicle speed is outside the predetermined range. A hybrid vehicle control device. In the hybrid vehicle control device according to claim 1,
The case where the vehicle speed is within a predetermined range is a case where there is a possibility that rattling noise is generated due to a collision between gears existing in the power transmission path. . In the hybrid vehicle control device according to claim 1 or 2,
In an operating state in which a large amount of power is generated using the driving force of the internal combustion engine, when the vehicle speed deviates from the predetermined range, the amount of power generated by using the driving force of the internal combustion engine is reduced. A control apparatus for a hybrid vehicle, characterized in that it is set to a small amount and a stop process of the internal combustion engine is started. In the control apparatus of the hybrid vehicle according to claim 1, 2, or 3,
The power transmission system is provided with two generator motors, and the other generator motor uses the driving force of the internal combustion engine to generate power while driving power is output from one generator motor. A control apparatus for a hybrid vehicle, characterized in that

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