JP2006158154A - Control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for vehicles by which a discharge load of a battery is not made excessive without losing a feeling of driving, when the vehicles are driven using a motor generator supplied from the battery. <P>SOLUTION: An HV_ECU executes a program which includes a step to detect an opening of an accelerator (S200), a step to detect a vehicle speed V (S400) when the opening of the accelerator does not correspond to a WOT (YES in S300), a step to compute target torque based on the opening of the accelerator (S600) when the vehicle speed V is in a region of higher vehicle speeds (YES in S500), a step to calculate an annealing parameter P based on the vehicle speed V (S700), a step to calculate a correction target torque using the target torque and the annealing parameter P (S800), and a step to compute engine torque and motor torque based on the correction target torque (S900). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for a vehicle driven by an electric motor using electric power of a power storage mechanism, and more particularly to a control device for avoiding a load on the power storage mechanism during acceleration of the vehicle without impairing driving feeling.

  A vehicle equipped with a power train called a hybrid system combining an engine (for example, a known engine such as a gasoline engine or a diesel engine) and an electric motor has been developed and put into practical use. In such a vehicle, regardless of the amount of accelerator operation by the driver, the operation by the engine and the operation by the electric motor are automatically switched and controlled so as to obtain the highest efficiency. For example, when the engine is operated in a steady state to operate a generator that charges a secondary battery (battery), or the engine is operated intermittently during traveling according to the amount of charge of the secondary battery, etc. In such a case, the engine is repeatedly operated and stopped regardless of the amount of accelerator operation by the driver. That is, by operating the engine and the electric motor individually or in cooperation, it becomes possible to improve fuel consumption and significantly reduce exhaust gas.

  With regard to such a hybrid system, Japanese Patent Application Laid-Open No. 2000-78705 (Patent Document 1) discloses a hybrid vehicle that suppresses vibration caused by motor control. This hybrid vehicle is mechanically coupled to an internal combustion engine, a power adjustment device that is coupled to both the output shaft and the axle of the internal combustion engine and can adjust power input / output on both shafts by exchanging electric power, and the axle. A hybrid vehicle capable of converting at least the power output from the internal combustion engine to be output from the axle and traveling, the target torque setting means for setting the target torque of the motor generator; Setting means for controlling the operation of the motor generator, specifying means for specifying the running state of the hybrid vehicle, target torque correcting means for correcting the target torque to achieve a predetermined response according to the running state Motor generator control means for outputting the target torque. The specifying means is means for specifying whether or not the hybrid vehicle is in a stopped state, and the responsiveness in the target torque correcting means is determined to be higher when the hybrid vehicle is stopped than when the hybrid vehicle is running. It is what.

According to this hybrid vehicle, since the passenger is generally very sensitive to the vibration of the vehicle while the vehicle is stopped, if the response of the motor generator is set by the target torque correcting means, the vehicle is higher when the vehicle is stopped than when the vehicle is traveling. The motor generator can be controlled with responsiveness. That is, even when the operating states of the internal combustion engine and the power adjustment device change and the torque output from both changes to the axle, the fluctuation can be quickly compensated by the motor generator. Therefore, the torque output to the axle can be maintained at a substantially constant value, and vibrations caused by changes in the operating state of the internal combustion engine and the power adjustment device can be suppressed while the vehicle is stopped.
JP 2000-78705 A

  However, the hybrid vehicle disclosed in Patent Document 1 can avoid load fluctuations of a power storage mechanism (for example, a secondary battery) during normal travel even if the target torque correction means can suppress vibration during stopping. Can not. That is, when the accelerator pedal is depressed during traveling, the vehicle is driven not only by the engine but also by the motor. In such a case, due to the difference in responsiveness between the engine and the motor (the motor is more responsive), the motor is operated or the torque generated from the motor is reduced in response to an increase in torque demand by the driver. When the vehicle speed is increased, a preferable acceleration feeling can be obtained in a region where the vehicle speed is low. However, in a region where the vehicle speed is relatively high, there may be a case where a preferable feeling of acceleration or the like cannot be obtained even if the torque generated from the motor is excessively increased as compared with a region where the vehicle speed is low. At this time, a large discharge load is applied to the secondary battery. When the accelerator pedal is returned in such a state, such a large discharge load disappears. If the occurrence or disappearance of a large discharge load is repeated in a short period of time (when load fluctuations occur frequently), the secondary battery may be quickly deteriorated. In other words, despite the fact that the load fluctuation is large and may cause deterioration of the secondary battery, the vehicle speed is relatively high, so that a large acceleration cannot be expressed and the driver feels sufficient acceleration. I can not feel.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to use an electric device (an electric motor or a motor generator (motor generator)) supplied from a power storage mechanism such as a battery or a capacitor. An object of the present invention is to provide a control device for a vehicle that can prevent an excessive discharge load of a power storage mechanism without impairing driving feeling when driving the vehicle.

  A vehicle control device according to a first aspect of the invention controls a vehicle that is driven by operating an electric device using electric power of a power storage mechanism. The control device includes a detection unit for detecting the speed of the vehicle, a calculation unit for calculating the required driving force, and a control unit for controlling at least one of the electric device and the power storage mechanism. The control means controls the electric device so as to suppress the responsiveness of the increase in the driving force using the electric device with respect to the increase in the required driving force when the vehicle speed of the vehicle is high compared to when the vehicle speed is low Including means.

  According to the first invention, in a region where the vehicle speed is relatively high, when the driver performs an accelerator operation in the partial region, a large required driving force is calculated and an electric device (here, a motor or a motor generator for driving the vehicle) is calculated. ) Is supplied with large electric power. However, at high speeds, it is difficult to realize an acceleration feeling that satisfies the driver even if the electric device is operated with a large amount of electric power compared to low speeds. In addition, if the driver frequently performs the accelerator operation, large discharge power may be generated or lost. For this reason, a control means suppresses the responsiveness of the increase in the driving force using an electric device with respect to the increase in the required driving force when the vehicle speed is high compared to when the vehicle speed is low. In this way, it is possible to prevent the discharge power from the power storage mechanism from increasing in a high-speed region where the driver cannot expect the acceleration feeling even when large electric power is discharged, and the driver's frequent accelerator It is possible to suppress variations in the discharge load (variations in which a large discharge load is generated or disappears) without sensitively responding to the operation. Even in this case, since a great acceleration feeling can be obtained at low speed, there is little possibility of impairing the driving feeling of the driver. When the discharge load is reduced in this way, deterioration of the power storage mechanism can be suppressed. As a result, when driving a vehicle using an electric device supplied from a power storage mechanism such as a battery or a capacitor, the vehicle control can prevent the discharge load of the power storage mechanism from becoming excessive without impairing the driving feeling. An apparatus can be provided.

  In addition to the configuration of the first invention, the control device according to the second invention further includes detection means for detecting an accelerator operation by the driver of the vehicle. The calculating means includes means for calculating the required driving force based on the detected accelerator operation.

  According to the second aspect, since the required driving force is calculated based on the accelerator operation indicating the driver's acceleration request, it is possible to correspond to the driving feeling of the driver.

  In addition to the configuration of the first invention, the control device according to the third invention further includes detection means for detecting an accelerator operation by the driver of the vehicle. The control means controls the electric device so as to suppress responsiveness in a region where the detected accelerator operation is not an operation corresponding to WOT (Wide Open Throttle) and the vehicle speed is higher than a predetermined speed. Means for doing so.

  According to the third invention, when the driver depresses the accelerator strongly and the accelerator opening degree corresponds to the WOT, discharge restriction is not performed, and the driver's driving feeling is satisfied. It is not an accelerator operation corresponding to WOT, and in a high vehicle speed range where sufficient acceleration can not be obtained even with a large discharge power, the increase in the discharge power from the power storage mechanism is suppressed, and the driver's frequent accelerator operation It is possible to suppress fluctuations in the discharge load without responding sensitively.

  In the control device according to the fourth invention, in addition to the configuration of any one of the first to third inventions, the control means increases the required driving force when the vehicle speed is high compared to when the vehicle speed is low. On the other hand, a means for controlling the electric device is included so as to suppress the responsiveness of the increase in the driving force using the electric device by smoothing the required driving force.

  According to the fourth aspect of the invention, the required driving force is corrected by the smoothing process, and the rate of change is suppressed, so that the discharge power from the power storage mechanism can be prevented from increasing, and the driver can frequently operate the accelerator. Variations in the discharge load can be suppressed without sensitively responding.

  In the control device according to the fifth invention, in addition to the configuration of any one of the first to third inventions, the control means increases the required driving force when the vehicle speed is high compared to when it is low. Means for controlling the electric device is included so as to suppress the responsiveness of the increase in driving force using the electric device by smoothing the output of the electric device.

  According to the fifth aspect of the present invention, the output from the electrical storage mechanism is increased by correcting the output from the electric device (vehicle driving motor or motor generator) by the smoothing process and suppressing the rate of change. While being able to suppress, the fluctuation | variation of discharge load can be suppressed, without responding sensitively to a driver | operator's frequent accelerator operation.

  In the control device according to the sixth invention, in addition to the configuration of the first invention, the control means increases the discharge power limit value in the power storage mechanism when the vehicle speed is high compared to when the vehicle speed is low. Includes means for controlling the power storage device.

  According to the sixth aspect of the invention, the discharge power from the power storage mechanism that supplies power to the electrical device can be more strongly limited at high speeds, and the increase in the discharge power from the power storage mechanism can be suppressed. Variations in the discharge load can be suppressed without sensitively responding to the accelerator operation.

  In the control device according to the seventh invention, in addition to the configuration of any one of the first to sixth inventions, the electric device is at least one of a motor and a motor generator, and the vehicle is an internal combustion engine in addition to the electric device. It is driven by operating the engine.

  According to the seventh invention, in a hybrid vehicle equipped with an internal combustion engine (engine) and a motor, it is possible to suppress an increase in discharge power from the power storage mechanism, and to respond sensitively to a driver's frequent accelerator operation. Therefore, fluctuations in the discharge load can be suppressed.

  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.

  A control block diagram of a hybrid vehicle according to an embodiment of the present invention will be described with reference to FIG. The present invention is not limited to the hybrid vehicle shown in FIG. It may be a hybrid vehicle having another aspect. Further, it may be an electric vehicle or a fuel cell vehicle. In addition, a power storage mechanism such as a capacitor may be used instead of the traveling battery.

  The hybrid vehicle includes an internal combustion engine (hereinafter simply referred to as an engine) 120 such as a gasoline engine or a diesel engine, and a motor generator (MG) 140 as drive sources. In FIG. 1, for convenience of explanation, the motor generator 140 is expressed as a motor 140A and a generator 140B (or a motor generator 140B), but the motor 140A functions as a generator depending on the traveling state of the hybrid vehicle. The generator 140B functions as a motor.

In addition to this, the hybrid vehicle transmits a power generated by the engine 120 and the motor generator 140 to the drive wheels 160, and a reduction gear 180 that transmits the drive of the drive wheels 160 to the engine 120 and the motor generator 140, and the engine 120. Power split mechanism (for example, planetary gear mechanism) 200 that distributes the generated power to two paths of drive wheel 160 and generator 140B, travel battery 220 that charges power for driving motor generator 140, and travel Inverter 240 that performs current control while converting the direct current of battery 220 and the alternating current of motor 140A and generator 140B, and a battery control unit (hereinafter referred to as a battery ECU (Electronic Control Unit)) that manages and controls the charge / discharge state of traveling battery 220 260) and En Engine ECU controlling an operation state of the emission 120
280 and MG_ECU 300 that controls motor generator 140, battery ECU 260, inverter 240, etc., and battery ECU 260, engine ECU 280, MG_ECU 300, etc. according to the state of the hybrid vehicle are mutually managed and controlled so that the hybrid vehicle can operate most efficiently. HV_ECU 320 and the like for controlling the entire hybrid system.

  In the present embodiment, converter 242 is provided between battery for traveling 220 and inverter 240. This is because the rated voltage of the traveling battery 220 is lower than the rated voltage of the motor 140A or the motor generator 140B, and therefore when the power is supplied from the traveling battery 220 to the motor 140A or the motor generator 140B, the converter 242 boosts the power. To do. This converter 242 has a built-in smoothing capacitor, and when the converter 242 performs a boosting operation, electric charge is stored in this smoothing capacitor.

  In FIG. 1, each ECU is configured separately, but may be configured as an ECU in which two or more ECUs are integrated (for example, MG_ECU 300 and HV_ECU 320, as shown by a dotted line in FIG. 1). An example is an integrated ECU).

  The power split mechanism 200 uses a planetary gear mechanism (planetary gear) in order to distribute the power of the engine 120 to both the drive wheel 160 and the motor generator 140B. By controlling the rotation speed of motor generator 140B, power split device 200 also functions as a continuously variable transmission. The rotational force of the engine 120 is input to the planetary carrier (C), which is transmitted to the motor generator 140B by the sun gear (S) and to the motor and the output shaft (drive wheel 160 side) by the ring gear (R). When the rotating engine 120 is stopped, since the engine 120 is rotating, the kinetic energy of this rotation is converted into electric energy by the motor generator 140B, and the rotational speed of the engine 120 is reduced.

  In a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, the hybrid vehicle travels only by the motor 140 </ b> A of the motor generator 140 when the engine 120 is inefficient, such as when starting or running at a low speed. During normal travel, for example, the power split mechanism 200 divides the power of the engine 120 into two paths, and on the other hand, the drive wheels 160 are directly driven, and on the other hand, the generator 140B is driven to generate power. At this time, the motor 140A is driven by the generated electric power to assist driving of the driving wheels 160. Further, at the time of high speed traveling, electric power from the traveling battery 220 is further supplied to the motor 140A to increase the output of the motor 140A and to add driving force to the driving wheels 160. On the other hand, at the time of deceleration, motor 140 </ b> A driven by drive wheel 160 functions as a generator to perform regenerative power generation, and the collected power is stored in traveling battery 220. When the amount of charge of traveling battery 220 decreases and charging is particularly necessary, the output of engine 120 is increased to increase the amount of power generated by generator 140B to increase the amount of charge for traveling battery 220. Of course, there is a case where control is performed to increase the drive amount of the engine 120 as necessary even during low-speed traveling. For example, it is necessary to charge the traveling battery 220 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 120 to a predetermined temperature.

  The technical feature of the present embodiment is that the discharge load of the traveling battery 220 is not excessive when driving the motor 140A during the above-described normal traveling to assist driving of the driving wheels 160. In the following description, the required driving force is calculated from the opening degree of the accelerator pedal, and the required driving force is smoothed so that the responsiveness is lowered at high speed compared to that at low speed.

  A control structure of a program executed by HV_ECU 320 of FIG. 1 will be described with reference to the flowchart of FIG.

  In step (hereinafter, step is abbreviated as S) 100, HV_ECU 320 determines whether or not the accelerator is in an ON state. This determination is made based on a signal input to HV_ECU 320 from a sensor provided on the accelerator pedal. If the accelerator is ON (YES in S100), the process proceeds to S200. If not (NO in S100), the process returns to S100.

  In S200, HV_ECU 320 detects the accelerator opening. In S300, HV_ECU 320 determines whether or not the accelerator opening is not the accelerator opening corresponding to WOT. This determination is made based on the magnitude relationship between the accelerator pedal opening and the accelerator opening threshold set in advance corresponding to WOT. If the accelerator opening is not the accelerator opening corresponding to WOT (YES in S300), it is determined that the vehicle is in the partial area (intermediate area), and the process proceeds to S400. If not (NO in S300), it is determined that the area is the WOT area, and the process ends without performing the processes of S400 to S900. At this time (NO in S300), the annealing process is not performed, and a large motor torque is generated so as to correspond to WOT.

  In S400, HV_ECU 320 detects vehicle speed V. At this time, for example, the vehicle speed V is detected based on the output shaft speed of the speed reducer 180 input from the ECT_ECU 1100 to the HV_ECU 320.

  In S500, HV_ECU 320 determines whether or not vehicle speed V is greater than a predetermined vehicle speed threshold value. If vehicle speed V is greater than the vehicle speed threshold (YES in S500), it is determined that the vehicle is in the high vehicle speed region, and the process proceeds to S600. Otherwise (NO in S500), it is not determined that the vehicle is in the high vehicle speed region, and this process ends.

  In S600, HV_ECU 320 calculates target torque Ttarget based on the accelerator opening. Note that the target torque Ttarget may be calculated based not only on the accelerator opening but also on the required driving force from an automatic driving control device (auto cruise) or the like. In S700, HV_ECU 320 calculates annealing parameter P based on the vehicle speed. At this time, the smoothing parameter P increases as the vehicle speed increases, and the annealing parameter P decreases as the vehicle speed decreases. For example, as shown in FIG. 3, any of a solid line, a one-dot chain line, and a two-dot chain line may be used. The higher the vehicle speed, the larger the annealing parameter P becomes. Further, the relationship between the vehicle speed and the tempering parameter P may be other than that shown in FIG.

  In S800, HV_ECU 320 calculates corrected target torque T. At this time, the corrected target torque T is calculated by T = (P−1) × Tpre / P + Ttarget / P. Tpre is the value of the corrected target torque T when this processing routine was executed last time. When the corrected target torque T is calculated in this way, the rate of change of the corrected target torque T can be suppressed as the value of the annealing parameter P increases. The corrected target torque may be calculated using an arithmetic expression other than this.

  In S900, HV_ECU 320 calculates engine torque and engine assist torque (motor torque) based on corrected target torque T. Thereafter, motor control is performed by the MG_ECU 300 so that the motor 140 generates the calculated motor torque.

  The operation of the vehicle equipped with the control device according to the present embodiment based on the structure and flowchart as described above will be described.

  While the vehicle is running, the driver performs an accelerator operation (depresses the accelerator pedal) (YES in S100), and if the accelerator opening is not an opening corresponding to WOT (YES in S300), the vehicle speed V is Detected.

  If vehicle speed V is greater than a predetermined threshold and is in a high vehicle speed range (YES in S500), target torque Ttarget is calculated based on the accelerator opening (S600). Furthermore, the annealing parameter P is calculated based on the vehicle speed V and the relationship between the vehicle speed V and the annealing parameter P as shown in FIG.

  The corrected target torque T is calculated using the target torque Ttarget and the annealing parameter P and the corrected target torque Tpre calculated in the previous processing routine (S800). Based on the corrected target torque T, the engine torque and the motor torque are calculated (S900).

  In this way, the motor torque can be calculated at a high speed so that the response of the target torque is slower (a rate of change is suppressed) than at a low speed.

  Referring to FIG. 4, for example, a case where the low vehicle speed is 20 km / h and the high vehicle speed is 80 km / h is compared. As shown in FIG. 4, in the case of a high vehicle speed, the responsiveness with respect to the request torque from a driver | operator is suppressed compared with the case of a low vehicle speed. In this way, it is possible to suppress an increase in the discharge power from the traveling battery 220 and to change the discharge load (a large discharge load is generated or lost without sensitively responding to the driver's frequent accelerator operation). Fluctuation).

  As described above, according to the control device of the present embodiment, the response to the required torque based on the driver's accelerator operation is suppressed at high speeds than at low speeds. For this reason, it is possible to avoid the generation of a large load of electric power used for acceleration at high speed and a large change rate. As a result, deterioration of the traveling battery can be prevented.

  In the above-described embodiment, the required torque is more strongly smoothed (lower responsiveness is processed) at higher speeds than at low speeds, but the required torque is not smoothed. May be subjected to an annealing process. Further, the discharge output limit value of the traveling battery 220 may be increased at higher speeds than at low speeds so that large power is not discharged at high speeds. In any case, when high acceleration is not obtained even when high discharge power is used from the traveling battery 220 at high speed, the discharge power from the traveling battery 220 can be limited. . In addition, the driver's frequent accelerator work is not responded with good responsiveness. Thereby, since the magnitude | size of load and the frequency of a load fluctuation can be reduced, the discharge load of the battery 220 for driving | running | working can be suppressed and deterioration of the battery 220 for driving | running | working can be avoided.

  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.

It is a control block diagram of the hybrid vehicle which concerns on embodiment of this invention. It is a flowchart which shows the control structure of the engine stop process performed by HV_ECU. It is a figure which shows the relationship with the vehicle speed V and the parameter P which is memorize | stored in HV_ECU. It is a timing chart which shows the time change of torque.

Explanation of symbols

  120 engine, 140 motor generator, 140A motor, 140B generator, 160 drive wheel, 180 reducer, 200 power split mechanism, 220 battery, 240 inverter, 242 converter, 260 battery ECU, 280 engine ECU, 300 MG_ECU, 320 HV_ECU.

Claims (7)

A control device for a vehicle driven by operating an electric device using electric power of a power storage mechanism,
Detecting means for detecting the speed of the vehicle;
A calculating means for calculating the required driving force;
Control means for controlling at least one of the electrical device and the power storage mechanism,
When the vehicle speed of the vehicle is high, the control means suppresses the responsiveness of the increase in the driving force using the electric device with respect to the increase in the required driving force. A control apparatus for a vehicle, including means for controlling an apparatus. The control device further includes a detecting means for detecting an accelerator operation by a driver of the vehicle,
The vehicle control device according to claim 1, wherein the calculating means includes means for calculating the required driving force based on the detected accelerator operation. The control device further includes a detecting means for detecting an accelerator operation by a driver of the vehicle,
The control means controls the electrical device so as to suppress the responsiveness in a region where the detected accelerator operation is not an operation corresponding to WOT and the vehicle speed is higher than a predetermined vehicle speed. The vehicle control device according to claim 1, comprising:   When the vehicle speed of the vehicle is high, the control means smoothes the required driving force with respect to the increase in the required driving force with respect to the increase in the driving force using the electric device. The vehicle control device according to claim 1, comprising means for controlling the electric device so as to be suppressed by processing.   When the vehicle speed of the vehicle is high, the control means performs the response of the increase of the driving force using the electric device to the increase of the required driving force, and the output of the electric device. The vehicle control device according to any one of claims 1 to 3, further comprising means for controlling the electric device so as to be suppressed by further processing.   The control means includes means for controlling the power storage device so as to increase a discharge power limit value in the power storage mechanism when the vehicle speed of the vehicle is high compared to when the vehicle speed is low. The vehicle control device described. The electrical device is at least one of a motor and a motor generator,
The vehicle control device according to claim 1, wherein the vehicle is driven by operating an internal combustion engine in addition to the electric device.

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