JP6064336B2 - Vehicle control device - Google Patents

Description

  The present invention relates to torque assist control using an electric motor mechanically coupled to an output shaft of an internal combustion engine via a belt or the like.

  Reference 1 discloses a configuration in which an electric motor having both an alternator function and a motor function is mechanically connected to an output shaft of an internal combustion engine via a belt or the like, and the internal combustion engine is started using the motor function of the electric motor. .

Japanese Patent No. 4451468

  By the way, in the configuration of Patent Document 1, the range of use of the motor function of the electric motor is limited at the time of starting the internal combustion engine. From the viewpoint of improving fuel efficiency, the motor function of the electric motor is used even during traveling, so-called torque. It is desirable to assist.

  However, the situation differs between when the internal combustion engine is started and when the vehicle is running. For example, the driver does not feel uncomfortable with the vibration of the internal combustion engine when starting the internal combustion engine, but feels uncomfortable with the vibration due to torque fluctuation during traveling even if the vibration is the same level as when starting. Probability is high. Also, with regard to belt slip, the state where the pulley is stationary and the state where it is rotating cannot be handled in the same way. That is, for torque assist by the electric motor, it is necessary to consider a control different from the internal combustion engine start by the electric motor.

  Therefore, an object of the present invention is to provide a control device that performs control suitable for torque assist during traveling.

The vehicle control device according to the present invention includes an operating state detecting means for detecting an operating state of the internal combustion engine, an electric motor mechanically connected to a drive shaft of the internal combustion engine by a belt or a chain, and operating the electric motor according to the operating state. Electric motor control means. The motor control means determines whether or not torque assist for applying driving force to the drive shaft of the internal combustion engine being driven by the electric motor is necessary based on the driving state, and executes the torque assist when executing the torque assist. to set based on the magnitude of the assist torque applied to the drive shaft to the operating state. Then, the motor control means, Rutotomoni gradually increasing the assist torque to the torque assist start to start torque assist, gradually reducing the assist torque when torque assist Exit to terminate the torque assist, the driver accelerator pedal When the accelerator operation for decreasing the opening is performed, or when the predetermined time has elapsed from the start of the torque assist, the torque assist is terminated, and the torque reduction speed for assist when the torque assist is terminated after the lapse of the predetermined time, Compared to the case where the operation is terminated according to the driver's accelerator operation, the size is reduced .

  According to the present invention, the assist torque is gradually increased at the time of starting the torque assist, so that the tension of the belt or the like can be prevented from abruptly increasing at the start of the torque assist and the slip of the belt or the like can be prevented.

FIG. 1 is a configuration diagram of a system according to an embodiment of the present invention. 2A shows the belt tension in the stationary state, FIG. 2B shows the belt tension in the state without torque assist, and FIG. 2C shows the belt tension in the state with torque assist. It is. FIG. 3 is a flowchart showing a control routine for torque assist. FIG. 4 is a time chart when the control routine of FIG. 3 is executed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a system configuration diagram showing an embodiment of the present invention. In the figure, solid lines indicate hard wire connections, broken lines indicate power transmission paths, and alternate long and short dash lines indicate a controller area network (hereinafter referred to as CAN). In the following description, the upper side in the figure is the front end side, and the lower side is the base end side.

  As shown in FIG. 1, the internal combustion engine 1 includes an electric motor 2 on one side surface and an air conditioner compressor 4 on the other side surface via brackets (not shown). A belt 8 is wound around a crank pulley 5 attached to the crankshaft tip of the internal combustion engine 1, an electric motor pulley 6 attached to the tip of the rotating shaft of the electric motor 2, and a compressor pulley 7 attached to the tip of the rotating shaft of the air conditioner compressor 4. These are mechanically connected.

  In FIG. 1, the three pulleys of the crank pulley 5, the motor pulley 6, and the compressor pulley 7 are mechanically connected by a single belt 8, but the motor pulley 6 and the compressor pulley 7 are respectively connected to different belts 8. May be mechanically connected to the crank pulley 5. A chain may be used instead of the belt.

  The internal combustion engine 1 includes a starter 9 in the vicinity of a connecting portion with a continuously variable transmission (hereinafter referred to as CVT) 11. The starter 9 includes a pinion gear that moves forward and backward in the same manner as a general starter, and during operation, the pinion gear engages with a gear provided on the outer periphery of a drive plate attached to the base end of the crankshaft to perform cranking. Do. The starter 9 is controlled by an under hood switching module (hereinafter referred to as USM) 23, and electric power necessary for operation is supplied from the main battery 16. The USM 23 also controls the air conditioner amplifier 22 and the like.

  The CVT 11 includes an oil pump 10 for shifting. The oil pump 10 operates in accordance with a shift instruction from the CVT controller 20.

  The electric motor 2 includes an inverter 3 and has a motor function that is driven by electric power supplied from the main battery 16 and a power generation function that is driven by the driving force of the internal combustion engine 1 to generate electric power. Further, when the power generation function of the electric motor 2 is used, the generated voltage can be variably controlled.

  Switching between the motor function and the power generation function is performed by an engine control module (hereinafter referred to as ECM) 19. The motor function is used mainly when returning from the idle stop and when executing torque assist during acceleration. Torque assist refers to assisting the output of the internal combustion engine 1 using the motor function of the electric motor 2 when a large output is required, such as during acceleration or traveling on an uphill road. The torque assist control will be described later.

  The main battery 16 supplies power to the first electric load group 40. The first electrical load group 40 is an electrical component group that can tolerate an instantaneous voltage drop called a so-called instantaneous drop during torque assist. In addition to the ECM 19, the starter 9, and the inverter 11, for example, a headlight, a wiper, and the like are included.

  Further, the system includes a sub battery 15. The sub battery 15 supplies power to the second electric load group 30. The second electrical load group 30 is an electrical component group that cannot tolerate a sag during torque assist, and includes, for example, each meter, a navigation system, and an air conditioner.

  Both the main battery 16 and the sub battery 15 are charged with the electric power generated by the electric motor 2. However, a relay 17 is interposed between the sub battery 15 and the electric motor 2. The relay 17 includes two relays, a relay 17A and a relay 17B, and is a so-called redundant system. The ECM 19 switches between the relay 17A and the relay 17B.

The ECM 19 reads detection signals from sensors that detect the operating state of the internal combustion engine 1, such as the accelerator opening sensor 18 and the crank angle sensor 12, and based on these signals, controls the general fuel injection amount, ignition timing, etc., and the relay described above. In addition to the control 17, torque assist control described later is performed. The ECM 19 includes a microcomputer that includes a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). It is also possible to configure the ECM 19 with a plurality of microcomputers.

  The ECM 19 forms a CAN with the CVT controller 20, the electric power steering controller 21, the air conditioner amplifier 22, the USM 23, and each meter 24.

  Next, switching of the motor function and power generation function of the electric motor 2 and switching of the relay 17 will be described for each operation scene.

  (A) In the system stop state, for example, from the end of vehicle operation to the next operation, both the relay 17A and the relay 17B are turned OFF.

  (B) When the internal combustion engine 1 is started by the driver's operation, the relay 17A and the relay 17B are both OFF and power is supplied from the main battery 16 to the starter 9, and the starter 9 starts the internal combustion engine 1. After the internal combustion engine 1 is completely exploded, the electric motor 2 generates power and turns on either the relay 17A or the relay 17B. Here, the target power generation voltage of the electric motor 2 is 14V, and the main battery 16 and the sub battery 15 are 14V in a fully charged state. Thereby, the charging of the main battery 16 and the sub battery 15 is completed by the electric power generated by the electric motor 2.

  (C) At the time of steady running or acceleration that does not involve torque assist, the state in which either the relay 17A or the relay 17B is turned on is maintained as in the start. And the electric motor 2 is made into a non-power-generation state by reducing the target electric power generation voltage of the electric motor 2 to about 12V, for example. Thereby, the load of the internal combustion engine 1 is reduced, and the fuel efficiency is improved.

  (D) At the time of deceleration, the state where either the relay 17A or the relay 17B is turned ON is maintained in the same manner as at the start. The electric motor 2 performs regenerative power generation with a target power generation voltage of 14 V and charges the main battery 16 and the sub battery 15.

  (E) When performing a so-called idle stop during vehicle operation, both the relay 17A and the relay 17B are turned OFF and the system is stopped.

  (F) When returning from the idle stop, both the relay 17A and the relay 17B remain OFF. Electric power is supplied from the main battery 16 to the electric motor 2, and the internal combustion engine 1 is started by causing the electric motor 2 to function as a motor. That is, when returning from the idle stop, the internal combustion engine 1 is restarted by the motor function of the electric motor 2 without using the starter 9.

  (G) After the complete explosion at the time of restart, the relay 17 opposite to that during the operation before the idle stop is turned on to switch the electric motor 2 to the power generation function.

  (H) When torque assist is executed, both the relay 17A and the relay 17B are turned OFF, and power is supplied from the main battery 16 to the electric motor 2. By turning off both relay 17A and relay 17B, sub battery 15 and electric motor 2 are electrically disconnected. Accordingly, it is possible to stably supply power from the sub battery 15 to the second electric load group 30 even during torque assist, and to prevent the second electric load group 30 from dropping instantaneously.

In this embodiment, for the sake of simplicity, torque assist is started when the change rate of the accelerator opening becomes equal to or greater than a predetermined value, and torque assist is performed until the accelerator opening decreases or until a predetermined time elapses from the start of torque assist. Shall continue .

  (I) After the torque assist is completed, the relay 17 opposite to that before the torque assist is performed is turned ON.

  Next, the control content of torque assist will be described. The “assist torque” in the following description is the torque that is applied to the crank pulley 5 by generating an output in the electric motor 2.

  FIG. 2 is a view of the crank pulley 5 and the motor pulley 6 as viewed from the front of the engine. For the sake of simplicity, the compressor pulley 7 is omitted, and a belt 8 is wound around the crank pulley 5 and the motor pulley 6. 2A shows a system stop state, FIG. 2B shows a state during engine operation without torque assist, and FIG. 2C shows a state where torque assist is being executed.

  As shown in FIG. 2A, the belt 8 is wound around the crank pulley 5 and the motor pulley 6 with a tension Tp. This tension Tp is called static tension.

  During steady running, that is, in a state where the electric motor 2 uses the power generation function during operation of the internal combustion engine 1, the balance of the tension of the belt 8 is lost as shown in FIG. The larger Tt and the other Ts smaller than the static tension Tp. Due to this tension difference, the power of the internal combustion engine 1 is transmitted to the motor pulley 6. Here, the tension Tt is called a tension side tension, and the tension Ts is called a loose side tension.

  When the torque assist is executed, the motor pulley 6 is driven, so that the tension side tension Tt is smaller and the loose side tension Ts is larger than that during steady running. When the torque assist is finished, the state returns to the state shown in FIG. That is, when the torque assist is started, the tension side tension Tt is small and the loose side tension Ts is large, and when the torque assist is finished, the tension side tension Tt is large and the loose side tension Ts is small.

  By the way, when the tension applied to the belt 8 is rapidly increased, the belt 8 may be deteriorated. On the other hand, if the tension applied to the belt 8 is rapidly reduced, belt slip may occur.

  The output generated by the electric motor 2 is transmitted to the internal combustion engine 1 via the belt 8 and becomes torque input to the crank pulley 5, that is, assist torque. Therefore, as the belt tension changes more rapidly, the vehicle acceleration changes more rapidly, and the driver is more likely to feel a torque shock. Therefore, the ECM 19 performs torque assist control as described below in order to suppress rapid fluctuations in belt tension.

  FIG. 3 is a flowchart showing a torque assist control routine executed by the ECM 19. This control routine is repeatedly executed at short intervals of about 10 milliseconds, for example.

In step S100, ECM19 is-out based on the detection signal of an accelerator opening sensor 18 reads the accelerator opening APO such as the operating state of the internal combustion engine 1.

  In step S110, the ECM 19 determines whether or not the accelerator opening change rate ΔAPO is equal to or higher than a predetermined determination value. The determination value is arbitrarily set for each vehicle specification to which the present system is applied. If ΔAPO is greater than or equal to the determination value, the process of step S120 is executed, and if ΔAPO is smaller than the determination value, the process of step S160 is executed.

  In step S120, the ECM 19 determines whether or not a set time has elapsed since the start of torque assist. The elapsed time (also referred to as assist time) since the start of torque assist is measured by a timer built in the ECM 19. That is, measurement is started at the start of torque assist, and a timer is initialized at the end of torque assist. The set time is provided to prevent excessive power consumption of the main battery 16 due to torque assist, and is set in advance according to the capacity of the main battery 16 and the like.

  If the assist time is within the set time, the process of step S130 is executed, and if the set time has elapsed, the process of step S180 is executed. If the assist time is not measured, the process of step S130 is executed.

  In step S130, the ECM 19 determines whether torque assist is possible based on the state of charge of the main battery 16, for example. If the charging state is such that torque assist can be executed for the set time described above, it is determined that torque assist is possible.

  The ECM 19 executes the process of step S140 if the torque assist is possible, and ends the current routine if it is not possible.

  In step S140, the ECM 19 turns on the assist command, and further sets the magnitude of the assist torque and the increase speed of the assist torque. Here, first, the magnitude of the assisting torque is set based on the driving state such as the vehicle speed, the engine rotational speed, the accelerator opening APO, the accelerator opening changing speed ΔAPO, and the like. The generated torque of the electric motor 2 is set based on the rotation speed. Then, an increasing speed of the assisting torque is set based on the changing speed of the torque generated by the electric motor 2 described later.

  In step S150, the ECM 19 executes torque assist by controlling the current supplied to the electric motor 2 so that the assist torque increases at the increasing speed set in step S140. When the assist torque reaches the set value, the value is maintained until the torque assist command is turned off.

  On the other hand, if it is determined in step S110 that the accelerator opening change speed is smaller than the determination value, the ECM 19 determines in step S160 whether the accelerator opening is decreasing. When the accelerator opening is decreasing, the process of step S170 is executed, and when it is not decreasing, the process of step S200 is executed. In step S200, the ECM 19 determines whether or not the assist time exceeds the set time. If the assist time exceeds the set time, the process of step S170 is executed, and if not, the current routine is terminated.

  In step S170, the ECM 19 determines whether or not torque assist is being executed. If it is being executed, the process of step S180 is executed. If not, the current routine is terminated.

  In step S180, the ECM 19 turns off the assist command, and further sets the assist torque decreasing speed. Note that when the assist time exceeds the set time and the assist command is turned OFF, the rate of decrease in the assist torque is made slower than when the accelerator opening APO is decreased and the assist command is turned OFF. Set. This is because the driver can predict the occurrence of the subsequent torque shock when the operation is terminated by the accelerator operation, while the driver cannot predict the operation when the operation is terminated after the set time has elapsed. In other words, the torque torque that can be tolerated by the driver is smaller when the operation is terminated by the elapse of the set time than when the operation is terminated by the accelerator operation.

  Here, the setting of the reduction speed of the assist torque will be described.

  In this embodiment, the assist torque decrease speed is set so that the change speed of the generated torque of the electric motor 2 is the same as that at the start of torque assist. The changing speed of the torque generated by the electric motor 2 is set in advance within a range of speeds in which torque shocks, belt slips, and the like can be prevented in advance.

  The generated torque of the electric motor 2 has a characteristic that it is higher at a low rotation and lower at a high rotation. And since the rotational speed of the electric motor 2 is lower than that at the end when torque assist is started, a higher torque is generated, and at the end, the torque is reduced by the increase in rotational speed. Therefore, if the change speed of the torque generated by the electric motor 2 is the same at the start and end of torque assist, the assist torque decrease speed becomes slower than the assist torque increase speed.

  When the increase speed and decrease speed of the assist torque are set as described above, the time required for the change of the assist torque (hereinafter referred to as the assist torque change time) is longer at the end than at the start of the torque assist. Shorter. In other words, when the generated torque of the electric motor 2 becomes high, torque shock or the like is prevented by gradually increasing the torque, and as the generated torque becomes low, the torque is reduced more quickly so that the assist torque disappears after the assist command is turned off. The responsiveness up to can be improved.

  Return to the description of the flowchart.

  In step S190, the ECM 19 ends the torque assist by controlling the current supplied to the electric motor 2 so that the assist torque decreases at the decreasing speed set in step S180.

  FIG. 4 is a time chart when the control routine is executed. The broken line in FIG. 4 is a chart described for comparison, and is a chart when the assist torque is changed stepwise at the start and end of torque assist. Note that “vehicle generation G” in the chart is not the acceleration of the entire vehicle but the acceleration due to the assist torque.

  At timing T1, the accelerator opening increases at an accelerator opening changing speed ΔAPO that is equal to or greater than the above-described determination value, and the assist command is turned ON accordingly, and the assist torque starts to increase. Actually, since the accelerator opening change speed ΔAPO is calculated after the accelerator opening starts to change, a delay time occurs from when the accelerator opening begins to change until the assist command is turned on. For simplicity, it is assumed that the assist command is turned ON when the accelerator opening changes at timing T1.

  Since the assist torque gradually increases after the start of torque assist, the vehicle generation G also gradually increases. On the other hand, when the assist torque is increased stepwise, the vehicle generation G is also increased stepwise. That is, by gradually increasing the assist torque as in the present embodiment, the increase in the vehicle generation G becomes moderate, and as a result, the torque shock applied to the vehicle occupant can be reduced.

  In addition, by gradually increasing the assist torque, the belt tension changes more gently than in the case where the assist torque is increased stepwise in both the tension side tension Tt and the loose side tension Ts. As a result, it is possible to prevent deterioration of the belt 8, slippage of the belt, and squeal when wet.

  When the accelerator pedal is closed and the assist command is turned OFF at timing T2 after the accelerator opening becomes constant, the assist torque starts to gradually decrease. When the assist torque gradually decreases, the vehicle generation G gradually decreases as compared with the case where the assist torque decreases stepwise. Thereby, the torque shock given to the passenger | crew of a vehicle can be reduced. Further, since the belt tension gradually changes, the deterioration of the belt 8 and the belt slip can be prevented as in the case where the assist torque is increased.

  At timing T3, the accelerator opening again increases, the assist command is turned on, and the assist torque gradually increases. Also here, the assist torque gradually increases, so that it is possible to reduce torque shock, promote deterioration of the belt 8, and prevent belt slipping.

  At the timing T4 when the set time of the assist time has elapsed from the timing T3, the accelerator pedal remains depressed, but the assist command is turned off when the set time has elapsed. Therefore, the assist torque is gradually decreased as compared with the timing T2. This makes it difficult for the driver to feel a torque shock even if the torque assist is terminated at a timing not intended by the driver.

  The effect of this embodiment described above will be described.

  When starting the torque assist, the assist torque is gradually increased, so that the tension fluctuation of the belt 8 can be moderated. That is, it is possible to prevent the tension side tension Tt from increasing suddenly and the loose side tension Ts from decreasing suddenly with the start of torque assist. If the belt tension increases abruptly, the deterioration of the belt 8 is promoted. Conversely, if the belt tension decreases abruptly, belt slip is likely to occur. It is possible to prevent deterioration and belt slippage. Further, torque shock due to sudden torque fluctuation can be suppressed.

  When the torque assist is finished, the assist torque is gradually decreased. As in the torque assist start, the torque shock is suppressed, and the belt tension fluctuation is moderated to promote the deterioration of the belt 8 and the belt slip. Can be prevented. In addition, it is possible to prevent squeal in the state where the belt 8 is flooded by traveling in a puddle.

  The torque reduction speed for assist at the end of torque assist is made faster than the torque increase speed for assist at the start of torque assist, so torque shock, belt slip, etc. without sacrificing responsiveness to start and end torque assist Can be prevented.

  When torque assist is terminated by operating the accelerator pedal, the assist torque reduction speed is set to be smaller than when the assist time ends because the set time has elapsed, so that it is difficult for the vehicle occupant to feel torque shock. be able to.

  In the system configuration diagram of FIG. 1, CVT 11 is described as a transmission, but other transmissions such as a stepped automatic transmission and a manual transmission may be used.

  The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made within the scope of the technical idea described in the claims.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Electric motor 3 Inverter 5 Crank pulley 6 Motor pulley 8 Belt 9 Starter 15 Sub battery 16 Main battery 17 Relay 19 Engine control module (ECM)

Claims (1)

An operating state detecting means for detecting an operating state of the internal combustion engine;
An electric motor mechanically coupled to the drive shaft of the internal combustion engine by a belt or chain;
Electric motor control means for operating the electric motor according to the operating state;
In a vehicle control device comprising:
The motor control means determines whether or not torque assist for applying driving force by the motor to the drive shaft of the driving internal combustion engine is necessary based on the driving state, and executes torque assist when executing torque assist. The magnitude of the assist torque to be applied to the drive shaft of the internal combustion engine is set based on the operating state, and the assist torque is gradually increased at the start of the torque assist to start the torque assist, and the torque The assist torque is gradually reduced at the end of the torque assist to end the assist,
The electric motor control means further terminates the torque assist when the driver performs an accelerator operation to decrease the accelerator pedal opening, or when a predetermined time has elapsed from the start of the torque assist, and performs the torque assist. A vehicle control device characterized in that an assist torque reduction speed when the operation is terminated after the predetermined time has elapsed is made smaller than when the operation is terminated in response to a driver's accelerator operation.

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