JP2010023637A - Control device for hybrid car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of a hybrid car easily and inexpensively configured, and equipped with an internal combustion engine and an electric power generator as a drive source for properly maintaining charging amounts of a battery, and for highly maintaining regenerative capability, and for promoting lengthening of a lifetime as well as durability of a battery. <P>SOLUTION: The control device of the hybrid car equipped with the internal combustion engine 1 and the electric power generator 2 as the drive source controls the driving of an electric power generator as a motor by a control circuit 5 in such a travel status that the drive torque of the hybrid car becomes negative while the electric power generator 2 is not driven as a motor. Thus, it is possible to consume electric energy stored in a battery 3, and to secure a regenerative power by making proper the charging status of the battery 3, and to promote the lengthening of a lifetime as well as the durability of the battery. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for a HEV (Hybrid Electric Vehicle) including an internal combustion engine and a motor generator as drive sources.

Conventionally, for example, in Patent Document 1, in a hybrid vehicle including an internal combustion engine and a motor generator as drive sources, regenerative braking is performed to charge a battery when decelerating or going down a slope. An apparatus is described in which the charging capacity is observed and the braking method can be selected in the order of only regenerative braking, combined use of regenerative braking and exhaust braking, and only exhaust braking according to the chargeable margin.
In Patent Document 2, in a hybrid vehicle, when an internal combustion engine (engine) is in an idling state, fuel supply to the internal combustion engine is cut off or restricted, while electric power is supplied from a battery to drive the motor generator. Is controlled to rotate the internal combustion engine at a necessary rotational speed, for example, to drive accessories.
JP 2007-168719 A JP 2003-235109 A

  Here, in a hybrid vehicle equipped with an internal combustion engine and a motor generator as drive sources, there is a demand for improving the durability of the battery and promoting a longer life so that the battery is not overcharged. .

  For this purpose, for example, in the device described in Patent Document 1, when the state of charge (SOC) of the battery is acquired and the amount of charge of the battery is not excessive, the amount of charge is large. It is assumed that exhaust braking is preferentially performed without performing regenerative braking.

  In the device described in Patent Document 2, the electric power stored in the battery is used in order to use the motor generator as an electric motor by shutting off or limiting the fuel supply to the internal combustion engine in the idling state of the internal combustion engine. Thus, the amount of charge of the battery can be reduced, and thus the desired amount of charge can be maintained.

  However, there is a possibility that the charge amount of the battery cannot be sufficiently reduced under a traveling state in which the idling state is less frequently or the idling state is maintained for a short time. The actual situation is that inefficient control is performed such that the electric energy generated without charging or recharging during the regenerative braking is discharged as thermal energy.

  The present invention has been made in view of such circumstances, and in a hybrid vehicle equipped with an internal combustion engine and a motor generator as drive sources, while maintaining a simple and inexpensive configuration, the charge amount of the battery can be appropriately maintained. Accordingly, an object of the present invention is to provide a control device for a hybrid vehicle that can maintain the regeneration performance high and promote the durability and the life extension of the battery.

For this reason, the control device for a hybrid vehicle according to the present invention provides:
A control device for a hybrid vehicle comprising an internal combustion engine and a motor generator as drive sources,
In a traveling state in which the driving torque of the hybrid vehicle is negative when the motor generator is not driven as a motor, the motor generator is driven and controlled as a motor.

  In the present invention, when the motor generator is driven and controlled as an electric motor in the traveling state, fuel supply to the internal combustion engine is limited.

  In the present invention, the traveling state in which the driving torque is negative may be a traveling state in which the internal combustion engine is driven by the drive shaft of the hybrid vehicle to provide traveling resistance.

  The present invention may be characterized in that the motor generator is driven and controlled as an electric motor in the traveling state on the condition that the motor generator battery is charged to a predetermined level or more.

  The present invention may be characterized in that the motor generator is driven and controlled as an electric motor in the traveling state while the vehicle speed is maintained within a predetermined range.

  According to the present invention, in a hybrid vehicle equipped with an internal combustion engine and a motor generator as drive sources, it is possible to appropriately maintain the amount of charge of a battery, and thus to achieve a regenerative capacity, with a simple and inexpensive configuration. It is possible to provide a control device for a hybrid vehicle capable of promoting the durability of the battery and extending its life while maintaining high.

  Hereinafter, an embodiment according to the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the examples described below.

  As shown in FIG. 1, the hybrid vehicle (HEV: Hybrid Electric Vehicle) according to the first embodiment of the present invention includes an internal combustion engine 1, a motor generator 2 rotationally connected to the internal combustion engine 1, a battery 3, and the like. The inverter circuit 4 provided between the battery 3 and the motor generator 2 is mounted. For example, as shown in FIGS. 2 and 3, the clutch mechanism includes a motor generator 2 that is rotationally connected to the output shaft of the internal combustion engine 1 and a transmission, or an internal combustion engine 1 and a motor generator. It is a hybrid vehicle that has an internal combustion engine 1 and a motor generator 3 as drive sources, and can be disposed between a transmission that is rotationally connected to the output shaft of the machine 2, and is driven by extending the drive shaft. The configuration is not limited to the configuration illustrated in FIGS. 1 to 3 and the like as long as the internal combustion engine 1 is rotated by receiving a reverse input from the wheel.

  When the motor generator 2 is driven by supplying a three-phase alternating current that gives a rotating magnetic field having a rotational speed larger than the rotational speed of the rotating shaft to the field winding, the motor generator 2 operates as an electric motor, When a three-phase alternating current that provides a rotating magnetic field having a rotational speed smaller than the rotational speed is supplied, the mechanical energy applied to the rotating shaft is converted into electric energy, which can be extracted from the field winding as a three-phase alternating current. It is configured as follows.

  The AC current supplied to the motor generator 2 so that the motor generator 2 functions as a vehicle drive source is obtained by converting the DC current supplied from the battery 3 by the inverter circuit 4. Further, the three-phase alternating current generated when the motor generator 2 is operated as a generator is converted into a direct current by the inverter circuit 4 and regenerated by charging the battery 3.

  The frequency on the AC side of the inverter circuit 4 (that is, the rotational speed of the rotating magnetic field of the motor generator 2) takes in the output of the rotation sensor 6 that detects the rotational speed of the rotating shaft of the internal combustion engine 1, that is, the motor generator 2. The control circuit 5 that controls the inverter circuit 4 is controlled based on the fetched output.

  That is, when the motor generator 2 is operated as an electric motor to perform auxiliary acceleration (assist), the control circuit 5 takes in the output of the accelerator sensor 17 that is interlocked with the operation of the accelerator pedal 21 and, for example, the rotation sensor 6 detects it. The inverter circuit 4 is controlled so that a rotating magnetic field slightly larger than the rotation speed (positive slip rate of 0 to several%) is generated in the field winding of the motor generator 2. At this time, energy is supplied from the battery 3 to the motor generator 2.

  When electric braking (regenerative braking) is performed by operating the motor generator 2 as a generator, the control circuit 5 is a rotating magnetic field that is slightly smaller (negative, that is, a rate of 0 to several percent) than the rotation speed detected by the rotation sensor 6. Is generated in the field winding of the motor generator 2. At this time, energy is supplied from the motor generator 2 to the battery 3 or is consumed by the resistor 11 via the semiconductor switch circuit 12.

  At this time, the terminal voltage of the battery 3 is observed by the detection circuit 13. If the battery 3 has a margin for charging, the switch control circuit 14 sets the semiconductor switch circuit 12 in a non-conducting state, and the current charges the battery 3. Flowing into.

  On the other hand, when the battery 3 is charged to a predetermined level and does not need to be charged, the switch control circuit 14 sets the semiconductor switch circuit 12 in a conductive state, and the electric energy generated by the regenerative braking of the motor generator 2 is a resistor. 11 is consumed.

  The vehicle speed sensor 16 is a sensor for detecting a vehicle speed by detecting, for example, wheel rotation or rotation on the output side of the transmission. The ratio of the rotational speed to the rotational speed on the output side) can be used to know which gear position the transmission is currently in. The transmission may be either an automatic transmission or a manual transmission. In the case of a continuously variable transmission, the gear ratio can be used as it is in the control described below without knowing the gear position.

  The standard terminal voltage of the battery 3 is, for example, 300V, which is converted to 24V by the DC / DC converter 19 for use in the electric equipment of the vehicle.

  The inverter circuit 4 sends energy from the battery 3 to the motor generator 2 when the motor generator 2 operates as an auxiliary acceleration motor, and the motor generator 2 operates when the motor generator 2 operates as a generator that performs electric braking. The electric energy generated in 2 is regenerated in the battery 3. The operation of the inverter circuit 4 is computer controlled by a control program set in the control circuit 5.

  Here, in the control circuit 5 according to the present embodiment, in the hybrid vehicle, the charge amount of the battery 3 can be appropriately maintained, so that the durability of the battery can be extended and the life can be increased, and the regenerative power can be increased. The following control is performed so that it can be appropriately secured.

That is, as shown in the flowchart of FIG.
In S (step, the same applies hereinafter) 1, the vehicle speed is acquired based on the signal from the vehicle speed sensor 16, and the vehicle speed is determined. For example, as shown in FIG. 5, the ON determination is maintained until the acquired actual vehicle speed exceeds a predetermined vehicle speed Vh until it falls below a predetermined vehicle speed VL (<Vh).

  If it is determined to be ON in S1, the process proceeds to S2, and if it is determined to be OFF, conventional control (for example, based on the state of charge of the battery 3, the amount of depression of the accelerator pedal 21, the vehicle traveling state such as the vehicle speed, etc.) Control for charging the battery 3 with electric energy generated during regenerative braking with reference to a map or the like, or using the resistor 11, or vehicle running conditions such as the amount of depression of the accelerator pedal 21 or the vehicle speed The internal combustion engine 1 and the motor generator so as to obtain the burden torques of the internal combustion engine 1 and the motor generator 2 with respect to the driver's required torque by referring to a predetermined map or the like based on Control for controlling the operation of the machine 2).

  In addition, while the fuel supply to the internal combustion engine 1 is cut off or restricted in the idling state of the internal combustion engine 1 as described in Patent Document 2, electric power is supplied from the battery 3 and the motor generator 2 is used as the motor. By controlling, it is also possible to perform control such that the internal combustion engine 2 is rotated at a necessary rotational speed and, for example, auxiliary machinery is driven.

In S2, a state of charge (SOC) such as a charge amount of the battery 3 is acquired based on a detection signal of a voltage sensor (not shown), and SOC determination is performed. For example, as shown in FIG. 6, the ON determination is maintained until the acquired actual SOC exceeds a predetermined charge amount SOCh and falls below a predetermined charge amount SOCL (<SOCh).
If it is determined ON in S2, the process proceeds to S3, and if it is determined OFF, conventional control is executed.
Note that when the driver depresses the brake pedal 22 and the brake sensor 18 outputs an ON signal, the ON determination is canceled and the conventional control can be executed.

In S3, the rotation speed (rotation speed) of the internal combustion engine 2 is acquired from the output signal of the rotation sensor 6, and the operation amount (depression amount) of the accelerator pedal 21 is acquired from the output signal of the accelerator sensor 17, and the driver's The required torque Treq is acquired.
Then, it is determined whether or not the following condition (1) is satisfied, and if satisfied (satisfied), the process proceeds to S4, and if not satisfied (unsatisfied), the process proceeds to the conventional control.
Treq−Tfric ≦ k × Tmmax and Ne> N (1)

Tfric: friction torque of the internal combustion engine 1 (where negative torque is expressed in absolute value)
Tmmax: full torque that can be generated by the motor generator 2 (rotary machine) k: aperture coefficient set according to the state of charge (SOC) (see the map in FIG. 7)
Ne: Actual rotational speed (rotational speed) of the internal combustion engine 1 (motor generator 2)
N: Lower limit value of the rotational speed (number of revolutions) of the internal combustion engine 1 (motor generator 2) for permitting the transition to this control

That is, if the speed is too low, vibration or the like may occur, so that the shift to this control is prohibited (determined based on the condition of Ne> N), but the rotation speed (vehicle speed) exceeds a predetermined value, and the driver's When the required torque Treq and the friction torque Tfric and the deviation of the internal combustion engine 1 are equal to or less than the torque (k × Tmmax) that permits the shift to the present control determined according to the state of charge, the motor generator 2 is used as a generator. The process proceeds to S4 in order to allow the shift to the main control for consuming the electric energy stored in the battery 3 by driving to make the charged state of the battery 3 appropriate.
However, the condition of Ne> N can be omitted when the required characteristics are satisfied or according to various requirements.

  On the other hand, when the driver's required torque Treq and the friction torque Tfric and the deviation of the internal combustion engine 1 are larger than the torque (k × Tmmax) that permits the start of this control determined according to the state of charge, the battery Since the charging amount of 3 is smaller than a predetermined amount, the control is shifted to the conventional control to prohibit the shift to the main control in which the motor generator 2 is driven as a generator.

In S4, the control circuit 5 controls the inverter circuit 4 so that the torque generated by the motor generator 2 is Tm = Treq + Tfric.
Further, the control circuit 5 sends a control command to the engine control circuit so that the generated torque Te = Tfric of the internal combustion engine 2 is satisfied, and in accordance with this, the engine control circuit stops the fuel supply or reduces the fuel supply amount, for example. Therefore, it is necessary to perform control for limiting the fuel supply.

  Specifically, when the charge amount of the battery 3 is more than a predetermined amount, the drive torque (the internal combustion engine 1 and / or the internal combustion engine 1 and / or the drive torque (EV start torque) Tev curve) of the motor generator 2 shown in the map of FIG. Alternatively, a traveling state in which the torque (including negative torque) generated by the motor generator 2 is on the upper side and the rotation speed of the internal combustion engine 1 (motor generator 2) is a predetermined or higher rotation speed (vehicle speed) ( When the required torque Treq belongs to the area A), the driving (assist) by the motor generator 2 is permitted, the electric energy stored in the battery 3 is consumed, and the state of charge of the battery 3 is made appropriate. This control for ensuring regenerative power is executed.

  Note that the drive torque is smaller than the full torque Tmmax that can be generated by the motor generator 2 above the horizontal axis (that is, drive torque = 0) in the map of FIG. 8, and the rotational speed of the internal combustion engine 1 (motor generator 2) is higher. In a traveling state (region A1) at a rotational speed (vehicle speed) that is equal to or higher than a predetermined value, the battery 3 consumes electric energy stored in the battery 3 by permitting driving (assist) by the motor generator 2 in the past. This is a region where control for making the state of charge appropriate is performed.

  That is, in the present embodiment, in addition to the area A1 where the conventional control has been performed in the past, in addition to the lower side of the horizontal axis (that is, driving torque = 0) in the map of FIG. In the inertial traveling region, etc., in the region where the internal combustion engine 1 is driven by the drive shaft and becomes resistance of traveling), the driving torque is higher than the driving start torque (EV start torque) Tev curve by the motor generator 2. In a running state (region A2) where the internal combustion engine 1 (motor generator 2) has a rotational speed (vehicle speed) that is equal to or higher than a predetermined value, the motor generator is Control for permitting the driving (assist) by 2 and consuming electric energy stored in the battery 3 to make the state of charge of the battery 3 appropriate is performed.

  Thus, for example, in a region where the driving torque is negative, such as when driving downhill (in a traveling state in which the internal combustion engine 1 is driven by the drive shaft to cause traveling resistance when the vehicle is coasting, etc.), the driver Even when the accelerator opening (the amount of depression of the accelerator pedal 21) is 0 or in a relatively small traveling state (corresponding to the area A2), driving by the motor generator 2 (assist is performed when the charge amount of the battery 3 is more than a predetermined value. ) Is permitted, the driving state (region) for permitting and executing the driving (assist) by the motor generator 2 is expanded as compared with the conventional case, and the frequency (opportunity) at which the control is permitted and executed is increased. Therefore, the electric energy stored in the battery 3 can be consumed more reliably, and the charged state of the battery 3 can be maintained in a more appropriate state.

  Region A2 is a traveling state (region) in which the driving torque is negative, for example, when driving downhill, and a traveling state (region) in which the driver's required torque is relatively small. For example, the region A2 has a gentle road surface gradient. It is assumed that the vehicle is coasting while maintaining a predetermined vehicle speed on a downhill. For example, the friction of the internal combustion engine 1 or the vehicle running resistance (road slope, air resistance, rolling resistance, etc.) The driving state is such that the driver depresses the accelerator pedal 21 to compensate for the decrease in the vehicle speed due to the vehicle. In such a state, driving (assist) by the motor generator 2 is executed, Reducing the burden on the driver without giving a sense of incongruity while consuming electric energy stored in the battery 3 and ensuring the regenerative power by making the state of charge of the battery 3 appropriate. It can become.

  In addition, the fuel supply to the internal combustion engine 1 can be limited (supply stop or reduction in supply amount) by executing driving (assist) by the motor generator 2 in such a traveling state (area A2). As a result, the emission amount of harmful components can be reduced, which can contribute to environmental protection.

  In the present embodiment, the friction torque of the internal combustion engine 1 is exemplified as a typical negative torque as Tfric, but vehicle running resistance (road surface gradient, air resistance, rolling resistance, etc.) is added to Tfric. It is also possible. The vehicle running resistance (road surface gradient, air resistance, rolling resistance, etc.) can be estimated from the vehicle running state (operation of the accelerator pedal 21, vehicle acceleration, etc.), for example.

  As described above, according to the present embodiment, the configuration in which the region of the traveling state in which the driving (assist) by the motor generator 2 has been permitted in the past is expanded to the inertial traveling region, for example, during downhill, Therefore, while reducing the burden on the driver without giving the driver a sense of incongruity, the electric energy stored in the battery 3 can be consumed to ensure the regenerative power by making the state of charge of the battery 3 appropriate. It becomes possible.

  In addition, according to the present embodiment, the area for permitting and executing the driving (assist) by the motor generator 2 is expanded as compared with the conventional case, and the fuel supply to the internal combustion engine 1 is restricted (supply stop) in this expanded area. In other words, the fuel consumption can be improved, the exhaust emission can be reduced, and the environment can be protected.

  The embodiments described above are merely examples for explaining the present invention, and various modifications can be made without departing from the scope of the present invention.

1 is a diagram schematically showing an overall configuration of a control apparatus for a hybrid vehicle according to an embodiment of the present invention. It is a figure which shows an example of the drive system layout which concerns on an Example same as the above. It is a figure which shows another example of the drive system layout which concerns on an Example same as the above. It is a flowchart explaining the traveling control which the control apparatus of the hybrid vehicle which concerns on an Example same as the above performs. It is a time chart for demonstrating the vehicle speed determination utilized in control same as the above. It is a time chart for demonstrating the SOC determination utilized in control same as the above. It is a figure which shows an example of the setting map of SOC aperture coefficient k utilized in control same as the above. It is the figure which showed an example of the travel map by the control apparatus of the hybrid vehicle which concerns on an Example same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Motor generator 3 Battery 5 Control circuit 6 Rotation sensor 16 Vehicle speed sensor 21 Accelerator pedal 22 Brake pedal

Claims (5)

A control device for a hybrid vehicle comprising an internal combustion engine and a motor generator as drive sources,
A control apparatus for a hybrid vehicle, wherein the motor generator is driven and controlled as an electric motor in a traveling state where the driving torque of the hybrid vehicle is negative when the motor generator is not driven as an electric motor.   The hybrid vehicle control device according to claim 1, wherein, when the motor generator is driven and controlled as an electric motor in the traveling state, fuel supply to the internal combustion engine is limited.   3. The hybrid vehicle according to claim 1, wherein the traveling state in which the driving torque is negative is a traveling state in which an internal combustion engine is driven by a drive shaft of the hybrid vehicle to generate traveling resistance. 4. Control device.   4. The drive control of the motor generator as a motor in the running state is performed on the condition that the battery for the motor generator is charged more than a predetermined value. 5. Hybrid vehicle control device. 5. The hybrid vehicle control according to claim 1, wherein the motor generator is driven and controlled as an electric motor in the traveling state while the vehicle speed is maintained within a predetermined range. apparatus.

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