JP2005012929A - Controller for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To elongate the life by effectively preventing the temperature rise of a battery, in a controller for a hybrid vehicle. <P>SOLUTION: The controller 10 for a hybrid vehicle, which has an engine 12 and a motor generator (MG)14 as drive sources, is equipped with a temperature detector 26 which detects the temperature of the battery 16 serving as a power source for MG14, and an HV-ECU(hybrid control unit)24 which decides the torque command value of MG14, based on the temporal change of the temperature of the battery 16 detected by the temperature detector 26. HV-ECU24 reduces the output torque of MG14 when the degree of temporal change of the temperature of the battery 16 gets over specified threshold. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control apparatus for a hybrid vehicle having an engine and a motor as drive sources, and more particularly to a technique that can improve the life of a battery serving as a power source for the motor.
[0002]
[Prior art]
When a battery for a motor of a hybrid vehicle exceeds an allowable temperature, problems such as electrode plate deterioration and liquid leakage may occur. Therefore, conventionally, a temperature detection unit for detecting the temperature of the battery is provided, and an allowable power value allowed for charging and discharging of the battery is derived at the detected temperature at that time, and the input power of the inverter obtained from the allowable power value is calculated. There has been proposed one that suppresses a battery temperature rise by determining a torque command value of a motor based on an allowable value (Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-112110
[Problems to be solved by the invention]
However, in the above prior art, when the power consumption of the battery is large, such as when the vehicle is accelerating or decelerating (during regeneration), the temperature may rapidly increase and reach the upper limit temperature. It was.
[0005]
Moreover, in the said prior art, although the upper limit temperature was not exceeded, there existed a case where the state of the temperature vicinity continued and deterioration of a battery advanced.
[0006]
[Means for Solving the Problems]
A hybrid vehicle control device according to the present invention is a hybrid vehicle control device having an engine and a motor as drive sources, the temperature detection unit detecting the temperature of a battery serving as a power source of the motor, and the temperature detection unit. And a controller that determines a torque command value of the motor based on a time change of the battery temperature.
[0007]
In the hybrid vehicle control device, it is preferable that the control unit determines the torque command value so that the torque of the motor becomes lower as the battery temperature increases with time.
[0008]
In the hybrid vehicle control device, it is preferable that the control unit further determines a torque command value according to a driving state and / or a traveling state of the vehicle.
[0009]
In the hybrid vehicle control device, it is preferable that the control unit determines a torque command value in accordance with a requested acceleration amount of the vehicle.
[0010]
In the control apparatus for a hybrid vehicle, when the degree of battery temperature rise exceeds a predetermined threshold value, the motor torque is reduced as compared with the case where the battery temperature does not exceed the threshold value, and the reduction amount is further reduced between the engine and the motor. It is preferable to change according to the elapsed time from the rise of the total output torque.
[0011]
In the hybrid vehicle control device, the control unit detects the temporary torque command value of the motor corresponding to the driving state and / or the traveling state of the vehicle from the temporary torque command value by the temperature detection unit. It is preferable to determine the torque command value as a value obtained by reducing the torque by an amount corresponding to the time change of the battery temperature.
[0012]
The hybrid vehicle control device preferably further includes an engine control unit that controls the output torque variable mechanism of the engine in accordance with a temporal change in the temperature of the battery detected by the temperature detection unit.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main configuration of a hybrid control apparatus 10 according to the present embodiment.
[0014]
As shown in FIG. 1, an engine 12 (for example, a gasoline engine) and a motor (for example, a motor / generator; hereinafter referred to as MG) 14 are mounted as drive sources in the hybrid vehicle. The sum of the output torque Te of the engine 12 and the output torque Tm of the MG 14 is the total driving torque T (= Te + Tm) of the vehicle. In the present embodiment, the case where a motor / generator having a function as a generator is used as the MG 14 is exemplified, but the present invention is also applicable to a vehicle provided with a separate generator.
[0015]
The power of MG 14 is supplied from battery 16 via inverter 18. A motor control unit (hereinafter referred to as MG-ECU) 20 controls the output torque Tm of MG 14 by controlling inverter 18.
[0016]
An engine control unit (hereinafter referred to as engine ECU) 22 controls the fuel injection amount, ignition timing, throttle opening, and the like of the engine 12. Further, the engine 12 is equipped with a variable output torque mechanism (for example, a variable valve system or an electronically controlled throttle), and the engine ECU 22 controls this according to the driving state and the traveling state, and the engine 12 is appropriately selected. The output torque Te can be increased or decreased. This torque control is used to compensate for the reduced motor torque Tm in order to suppress the temperature rise of the battery 16.
[0017]
The hybrid control unit (hereinafter referred to as HV-ECU) 24 includes various parameters (for example, engine speed, requested acceleration amount [for example, accelerator depression amount], vehicle, etc.) Speed, deceleration request amount (for example, brake pedal ON / OFF and depression amount, shift stage, steering angle, etc.) are acquired. Further, the HV-ECU 24 acquires the battery temperature tb from the temperature sensor 26 provided in the battery 16.
[0018]
And HV-ECU24 respond | corresponds to the said parameter, battery temperature tb, and the time change (for example, battery temperature change in a predetermined time interval) with reference to the map (information) hold | maintained, for example. An engine torque Te and a motor torque Tm are acquired.
[0019]
FIG. 2 is a diagram illustrating an example of a temporal change in the temperature of the battery 16. As shown in FIG. 2, even if the temperature tb _{0 of the} battery 16 detected at a certain time is the same, the ultimate temperatures tb _1s and tb _2s differ depending on the magnitude of the time changes Δtb ₁ and Δtb ₂ of the temperature at that time. If the degree of increase is large, the upper limit temperature may be exceeded. Therefore, the HV-ECU 24 according to the present embodiment generates the engine torque Te and the motor torque Tm for preventing the upper limit temperature from being reached based on the time change of the battery temperature in addition to the battery temperature tb acquired in each case. get. Thereby, it is possible to more reliably prevent the battery temperature from exceeding the upper limit temperature (allowable temperature), and to extend the life of the battery 16.
[0020]
The HV-ECU 24 obtains the temporary engine torque Te ′ and the temporary motor torque Tm ′ corresponding to the above parameters without considering the temperature tb and temperature change of the battery 16, and uses them as the battery temperature tb and / or its time. You may make it acquire engine torque Te and motor torque Tm by correct | amending based on a change. That is, when the battery temperature tb and / or its change over time (for example, the degree of time rise) is less than a predetermined threshold (that is, when reaching the upper limit temperature [allowable temperature] of the battery temperature is not predicted), the temporary engine torque Te ′ and provisional motor torque Tm ′ are directly used as engine torque Te and motor torque Tm, and on the other hand, when battery temperature tb and / or its change over time exceeds a threshold value (that is, reaching the upper limit temperature [allowable temperature] of battery temperature). Is predicted), the temporary engine torque Te ′ and the temporary motor torque Tm ′ are corrected according to the battery temperature tb and / or its change over time with reference to the map, and the corrected values are used as the engine torque. Te and motor torque Tm may be used.
[0021]
The HV-ECU 24 inputs a torque command value Te * corresponding to the engine torque Te to the engine ECU 22 and inputs a torque command value Tm * corresponding to the motor torque Tm to the MG-ECU 20. The engine ECU 22 controls the engine 12 based on the torque command value Te *, and the MG-ECU 20 controls the inverter 18 based on the torque command value Tm *.
[0022]
Next, a specific example of control of the motor torque Tm and the engine torque Te by the HV-ECU 24 according to the present embodiment will be described with reference to the drawings.
[0023]
FIG. 3 is a diagram showing temporal changes in the total drive torque (T, T1, T2), the engine torque Te, and the motor torque (Tm, Tm1, Tm2) in a certain driving state (or running state). (A) is a diagram when the motor torque Tm is not limited (normal state), and (b) is a diagram when the motor torque Tm is limited according to the temperature Tb of the battery 16 and its change over time. is there. The horizontal axis is time, and the vertical axis is torque.
[0024]
When the temperature tb of the battery 16 and its change over time (time increase degree) are sufficiently small and the motor torque Tm is not limited, an acceleration request (depressing the accelerator) is made as shown in FIG. Then, the total driving torque T is set to a stepped shape that rises sharply from time ts. At this time, since the engine torque Te increases gently, the step-like total driving torque T is realized by setting the motor torque Tm in the hatched region of FIG.
[0025]
On the other hand, when the temperature tb of the battery 16 and / or its time change (time increase degree) is large and exceeds a predetermined threshold set for them, the MG 14 outputs the motor torque Tm of FIG. When the temperature tb of the battery 16 may reach the upper limit temperature, the motor torque Tm is limited as shown in FIG. 3B to suppress the power consumption of the battery 16. The motor torque (Tm1 [upwardly hatched], Tm2 [shaded]) is smaller than in the case of (a) (Tm>Tm1> Tm2), and the engine torque Te is the same as in the case of (a). T1 and T2 are smaller than in the case of (a) (T>T1> T2). Thus, by reducing the motor torque Tm, the power consumption of the battery 16 is reduced, the temperature rise is suppressed, and the effect that the life is extended is obtained. Note that, as the motor torque Tm increases, the power consumption of the battery 16 increases and the temperature tb increases. In this embodiment, the motor torque Tm decreases as the temperature tb of the battery 16 or the degree of time rise increases. To do.
[0026]
FIG. 4 is a diagram showing temporal changes in total drive torque (T, T11, T12), engine torque Te, and motor torque (Tm, Tm11, Tm12) in an operation state (or running state) different from FIG. . FIG. 4 shows an example in which the required acceleration amount (for example, accelerator depression amount) is larger than that in FIG. In the case of FIG. 3A, the motor torque Tm is output until the engine torque Te reaches a predetermined value from the time of rising, and the output of the motor torque Tm is stopped when the engine torque Te reaches the predetermined value. Yes. On the other hand, if the requested acceleration amount is large, the total drive torque T needs to be increased correspondingly. Therefore, in the case of FIG. 4A, the motor torque Tm is added to the engine torque Te even after startup. In this way, the motor torque Tm is continuously output. Also in this figure, (a) is a diagram when the motor torque Tm is not limited, and (b) is a case when the motor torque Tm is limited according to the temperature tb of the battery 16 and its change over time. FIG. The horizontal axis is time, and the vertical axis is torque.
[0027]
When the temperature tb of the battery 16 and its change over time (degree of time increase) are sufficiently small and the motor torque Tm is not limited, as shown in FIG. 4A, an acceleration request (depressing the accelerator) is performed at a certain time. ), The total driving torque T is set to a stepped shape that rises sharply from time ts. At this time, since the engine torque Te increases gently, the step-like total driving torque T is realized by setting the motor torque Tm in the hatching region of FIG.
[0028]
On the other hand, when the temperature tb of the battery 16 and / or its time change (degree of time rise) is large and exceeds a predetermined threshold set for the battery 16 and the MG 14 outputs the motor torque Tm of FIG. When the temperature tb may reach the upper limit temperature, the motor torque Tm is limited as shown in FIG. 4B to suppress the power consumption of the battery 16. The motor torque (Tm11 [upwardly hatched], Tm12 [shaded]) is smaller than that in (a) (Tm>Tm11> Tm12), and the engine torque Te is the same as in (a). T11 and T12 are smaller than in the case of (a) (T>T11> T12). Thus, since the power consumption of the battery 16 is reduced by reducing the motor torque Tm, an increase in the temperature of the battery 16 is suppressed, and the life of the battery 16 is increased. Even in this case, the motor torque Tm is reduced as the temperature tb of the battery 16 or the degree of time rise thereof is higher.
[0029]
Now, comparing the case of FIG. 4B and the case of FIG. 3B, it can be seen that the time-varying characteristics of the motor torque limited to suppress the temperature rise of the battery 16 are different. Specifically, for example, in the case of FIG. 4B, when a predetermined time elapses from the rising time ts and the engine torque Te reaches a predetermined value (time t1), the motor torque (Tm11, Tm12). ), And the motor torque Tm when the time change of the temperature of the battery 16 is small and the motor torque (Tm11, Tm12) when the time change exceeds a predetermined threshold are different values. . On the other hand, in the case of FIG. 3B, the motor torques Tm1 and Tm2 are zero regardless of the time change of the temperature of the battery 16 at the time t1 when the same time has elapsed from the rising time ts. In other words, in the present embodiment, the motor torque Tm (the limit amount) is not determined on a one-to-one basis with respect to the detected temperature tb of the battery 16 and / or its change over time, but the driving state and / or traveling of the vehicle. The motor torque Tm (the limit amount) is appropriately determined according to the state (for example, the requested acceleration amount).
[0030]
FIG. 5 shows the total driving torque (T21, T22), engine torque Te, and motor torque (Tm21, Tm22) when the same operating state (or running state) as FIG. It is a figure which shows a time-dependent change. FIG. 5 is a diagram when the motor torque Tm is limited in accordance with the temperature tb of the battery 16 and its change over time. The case where the motor torque Tm is not limited is the same as that shown in FIG. The horizontal axis represents time, and the vertical axis represents torque, and the notation is the same as in FIGS.
[0031]
As shown in FIG. 5, in this case, even when an abnormality is detected in the temperature tb of the battery 16 and its change over time, the motor torque Tm at the rise of the total drive torque T (within a predetermined time from the start of the rise). I am trying not to restrict it. If the motor torque Tm is limited from the start of the rise of the total drive torque T as in the case of FIG. 4B, the acceleration performance from the vehicle stop state deteriorates. By not limiting the motor torque Tm within a predetermined time from the start time ts), it can be suppressed. This also provides an effect that it is difficult for the driver to feel a sense of discomfort associated with the decrease in the acceleration performance. Note that after a predetermined time has elapsed since the start of rising ts, the motor torque Tm is limited as in FIG.
[0032]
FIG. 6 shows the total drive torque (T31, T32), engine torque Te, and motor torque (Tm31, Tm32) when control is performed with different logic for the same operating state (or traveling state) as in FIG. 4 and FIG. It is a figure which shows a time-dependent change. FIG. 6 is a diagram in the case where the motor torque Tm is limited according to the temperature tb of the battery 16 and its change over time. The case where the motor torque Tm is not limited is the same as that shown in FIG. The horizontal axis represents time, and the vertical axis represents torque, and the notation is the same as in FIGS.
[0033]
As shown in FIG. 6, in this case, the HV-ECU 24 causes the engine 12 to output an engine torque Te1 that is larger than the engine torque Te in the case of FIG. 5, thereby driving the total drive by limiting the motor torques Tm31 and Tm32. The decrease in torque T31, T32 is compensated. By doing so, it is possible to suppress a decrease in acceleration performance from the vehicle stop state even during a period in which the motor torque Tm is limited. This also provides an effect that it is difficult for the driver to feel a sense of discomfort associated with the decrease in the acceleration performance. In this case, the motor torque Tm is also limited after a predetermined time has elapsed from the rising start ts, as in FIG.
[0034]
【The invention's effect】
As described above, according to the present invention, since the output torque of the motor is limited not only based on the temperature of the battery but also based on the time change (especially the degree of time rise) of the temperature, It is more reliably suppressed and the lifetime can be extended. In addition, by appropriately controlling the motor output torque according to the driving state and running state of the vehicle, the time from the start of start-up, etc., it is possible to suppress the reduction in various performances of the vehicle due to the limitation of the motor torque. Can do.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a main part of a hybrid control device according to an embodiment of the present invention.
FIG. 2 is a diagram showing a difference in reached temperature due to a change in battery temperature with time.
FIG. 3 is a diagram illustrating an example of torque control by the hybrid control device according to the embodiment of the present invention.
FIG. 4 is a diagram showing another example of torque control by the hybrid control device according to the embodiment of the present invention.
FIG. 5 is a diagram showing another example of torque control by the hybrid control device according to the embodiment of the present invention.
FIG. 6 is a diagram showing another example of torque control by the hybrid control device according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Hybrid control apparatus, 12 Engine, 14 Motor, 16 Battery, 18 Inverter, 20 MG-ECU (motor control part), 22 Engine ECU (engine control part), 24 HV-ECU (hybrid control part), 26
Temperature sensor.

Claims (7)

A control device for a hybrid vehicle having an engine and a motor as drive sources,
A temperature detector that detects the temperature of the battery that is the power source of the motor;
A control unit for a hybrid vehicle, comprising: a control unit that determines a torque command value of a motor based on a change in battery temperature with time detected by the temperature detection unit. 2. The control apparatus for a hybrid vehicle according to claim 1, wherein the control unit determines a torque command value so that the torque of the motor decreases as the degree of time increase of the battery temperature increases. The said control part further determines a torque command value according to the driving | running state and / or driving | running | working state of a vehicle, The control apparatus of the hybrid vehicle of Claim 1 or 2 characterized by the above-mentioned. The control device for a hybrid vehicle according to claim 3, wherein the control unit determines a torque command value according to a requested acceleration amount of the vehicle. When the time rise in battery temperature exceeds a predetermined threshold, the control unit reduces the motor torque as compared with the case where the threshold does not exceed the threshold, and further reduces the amount of increase of the total output torque of the engine and the motor. The hybrid vehicle control device according to any one of claims 1 to 4, wherein the control device is changed according to an elapsed time from the vehicle. The control unit is configured to detect a motor temporary torque command value corresponding to a driving state and / or a traveling state of the vehicle according to a time change of a battery temperature detected by the temperature detection unit from the temporary torque command value. The control apparatus for a hybrid vehicle according to any one of claims 1 to 5, wherein the torque command value is determined as a value obtained by reducing the torque only. Furthermore, the engine control part which controls an engine output torque variable mechanism according to the time change of the temperature of the battery detected by the said temperature detection part is provided, It is any one of Claims 1-6 characterized by the above-mentioned. The hybrid vehicle control apparatus described.

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