JP2004092455A - Output control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a driving loss of a supercharger, to decrease the fuel consuming rate of an engine, and to improve fuel economy, by controlling a supercharging degree and motor torque according to a battery charging state with a simply structured device. <P>SOLUTION: In the output control device 10 for a hybrid vehicle 1 comprising the engine 2 provided with the supercharger 15 and a motor generator 3, a charging state detecting means 22, a supercharging degree adjusting means 20, and a motor generator torque adjusting means 21 are provided. When a discharging state of the battery is not less than a specified value, the supercharging degree adjusting means 20 decreases the supercharging degree of the supercharger 15, and the motor generator torque adjusting means 21 adds the motor torque to engine torque. When the charging state of the battery is less than the specified value, the supercharging degree adjusting means increase the supercharging degree of the supercharger 15. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides an engine provided with a supercharger, a motor having both a function as an electric motor for assisting the driving force of the engine and a function as a generator for charging a battery using the driving force of the engine. The present invention relates to an output control device for a hybrid vehicle including a generator.
[0002]
[Prior art]
Conventionally, a hybrid vehicle including an engine with a turbocharger and a motor generator has been known. The turbocharger sends compressed air to the engine to increase the engine torque, and at the same time, drives the motor / generator. By driving the motor, the motor torque can be added to the engine torque.
[0003]
FIG. 5 is a graph showing the contents of output control with respect to engine load when the engine speed is kept constant in a conventional hybrid vehicle equipped with a supercharged engine and a motor generator. The thick solid line on the graph indicates the operation when the state of charge of the battery is high, and the thin solid line indicates the operation when the state of charge is low. The broken line represents the engine fuel consumption rate when there is no supercharger.
[0004]
First, when the state of charge of the battery is low (thin solid line), when the accelerator pedal is depressed and the required power plant load increases, the throttle valve is gradually opened, and the supercharging pressure increases in proportion to the throttle valve opening. . On the other hand, the motor / generator torque does not drive the motor / generator because the state of charge of the battery is not sufficient, and remains at 0. Therefore, the vehicle is driven only by the engine torque.
The fuel consumption rate decreases in accordance with the opening degree of the throttle valve, and the fuel efficiency is slightly improved. However, the fuel consumption rate increases again near the full opening of the throttle valve, and the fuel efficiency deteriorates.
[0005]
On the other hand, when the state of charge of the battery is high (thick solid line), when the required load of the power plant exceeds a predetermined load (R ₁ ), the motor-generator functions as a motor and functions to assist the engine torque. . Since the throttle valve is not opened any more, the boost pressure also takes a constant value. Therefore, the fuel consumption rate of the R ₁ or more power plant required load range is slightly improved as compared with the case of low charge state, it takes an almost constant value.
[0006]
Here, for each fuel consumption rate, compared to the engine fuel consumption rate without a supercharger, indicated by the broken line in the figure, the power plant required load is large and the entire battery is large except when the battery charge state is high, Fuel economy is poor. This is because the supercharged engine consumes energy due to the driving of the supercharger and the resistance accompanying the driving. That is, in the supercharged engine, there is a problem that a loss in supercharger driving (supercharge loss) occurs, and therefore, the fuel consumption rate of the engine is large and the fuel consumption is correspondingly poor.
[0007]
In order to solve such a problem, in the related art, a turbocharger driven by exhaust gas is provided with a generator (turbo generator) having a function as a generator, and the electric power generated by the turbo generator is stored in a battery, and the torque is reduced. It is designed to be used for assisting, and the fuel consumption rate can be reduced by using exhaust energy (for example, see Patent Document 1).
[0008]
In addition, a cranking motor for driving the supercharger is provided, and the supercharger is driven by this cranking motor instead of the engine. A technique for reducing the consumption rate is also disclosed (see Patent Document 1).
[0009]
[Patent Document 1]
JP-A-11-332015 (pages 3-5, FIGS. 1, 7)
[0010]
[Problems to be solved by the invention]
However, the former technique cannot be applied to a general turbocharged engine because a turbocharger is provided with a generator having a function as a generator. This technology also relates to the reuse and operation of exhaust energy, which generates power by the driving force of the turbocharger and acts to offset the driving loss of the turbocharger by using the generated energy. Things. That is, this is not a technique for reducing the drive loss of the supercharger, but merely for increasing the additional power to the supercharger.
[0011]
In the latter technology, the vehicle is provided with a cranking motor for driving the supercharger.However, when applied to a conventional turbocharged engine, additional equipment is required, Is also complicated. This technique is not for reducing the drive loss of the supercharger, but for transferring the load of the supercharger driving force from the engine to the cranking motor. In other words, this is merely a technique for transferring the burden of the power for driving the supercharger to other than the engine, instead of reducing the drive loss of the supercharger.
[0012]
SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and is an output control device of a hybrid vehicle having an engine provided with a supercharger and a motor / generator. By controlling the supercharging degree and the motor torque, the drive loss of the supercharger is reduced, and the fuel consumption rate of the engine is reduced to improve the fuel efficiency.
[0013]
[Means for Solving the Problems]
Therefore, the output control device for a hybrid vehicle according to the first aspect of the present invention utilizes an engine provided with a supercharger, a function as an electric motor for assisting the driving force of the engine, and the driving force of the engine. In an output control device for a hybrid vehicle including a motor generator having a function as a generator for charging a battery, a supercharge degree adjusting means adjusts a supercharge degree of the supercharger to detect a charge state. Means for detecting the state of charge of the battery; motor / generator torque adjusting means for adjusting the motor / generator torque; and when the state of charge of the battery detected by the state of charge detection means is equal to or higher than a predetermined value, the supercharging is performed. The degree adjusting means reduces the supercharging degree of the supercharger and the motor / generator torque adjusting means drives the motor / generator to a motor. When the state of charge of the battery detected by the state-of-charge detecting means is less than a predetermined value, the supercharge degree adjusting means increases the supercharge degree of the supercharger. And
[0014]
Preferably, the supercharging degree adjusting means adjusts the supercharging degree by opening and closing the waste gate valve (claim 2). On the other hand, preferably, the supercharger is a variable capacity supercharger, and the supercharge degree adjusting means adjusts the supercharge degree by changing the capacity of the supercharger (claim 3).
In addition, when the state of charge of the battery is less than a predetermined value, it is preferable that the motor / generator torque adjusting means does not drive the motor / generator by motor (claim 4), and the state of charge of the battery is not less than a predetermined value. In some cases, it is more preferable that the motor / generator torque adjusting means adds the motor torque according to the magnitude of the difference between the required torque and the engine torque (claim 5), and furthermore, the state of charge of the battery is less than a predetermined value. In this case, it is preferable that the supercharging degree adjusting means adjusts the supercharging degree in accordance with the magnitude of the required torque (claim 6).
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIGS. 1 to 4 show an output control device for a hybrid vehicle as an embodiment of the present invention. FIG. 1 is a schematic diagram showing the overall configuration of the hybrid vehicle, and FIG. FIG. 3 is a flowchart illustrating the determination, and FIG. 3 is a diagram illustrating a control operation in the present control device. FIG.
[0016]
As shown in FIG. 1, the hybrid vehicle 1 according to the present embodiment includes an engine 2, a motor / generator 3, a transmission 5, a controller (output control device) 10, a turbocharger (supercharger) 15, and the like as main devices. I have.
The engine 2 is configured as a general internal combustion engine equipped with a turbocharger 15, and its driving torque is transmitted to the motor generator 3 via the engine output shaft 2a, and the motor / generator output shaft 3a, the clutch 4, the transmission 5 and The drive wheel 7 is transmitted to the left and right drive shafts 11 a and 11 b via the differential device 6 to drive the drive wheels 7. The engine output shaft 2a and the motor / generator output shaft 3a are connected to each other directly or via a gear inside the motor / generator 3 so as to rotate integrally.
[0017]
The turbocharger 15 uses a pressure of exhaust gas passing through an exhaust pipe 16 of the engine 2 to rotate a turbine that rotates integrally with a compressor (not shown) in an intake pipe 17, and functions to supercharge intake air in the intake pipe 17. I do. Further, the turbocharger 15 includes a wastegate valve 12 that adjusts the degree of supercharging by allowing exhaust gas to escape to the downstream side of the turbine by bypassing the turbine.
[0018]
The motor / generator 3 has both a function as a motor and a function as a generator. When functioning as a generator, the motor / generator 3 generates electric power using torque input from the engine output shaft 2a and charges a battery (not shown). Has become. When functioning as a motor, a driving force is generated by using the power of a battery (not shown), and the torque input from the engine output shaft 2a is added to the torque by the motor and output to the motor / generator output shaft 3a. It has become. The motor / generator output shaft 3a is connected to a transmission 5 via a clutch 4 that can be connected and disconnected.
[0019]
The controller 10 is a control device for cooperatively controlling the engine 2 and the motor / generator 3, and has a storage device (not shown) provided for storing various sensors (not shown), input / output devices, control programs, control maps, and the like. ROM, RAM, etc.), a central processing unit (CPU), a counter, and the like. An external input side of the controller 10 includes an accelerator pedal stroke sensor 13 for detecting an operation amount of the accelerator pedal 9 and an engine speed for detecting an engine speed (equivalent to an engine speed per predetermined time, that is, an engine speed). A speed sensor 14, a supercharging pressure sensor (supercharging pressure detecting means) 19 for detecting a supercharging pressure, and the like are connected. A waste gate valve 12, a throttle valve 18, and the like are connected to an external output side of the controller 10.
[0020]
Next, the main part of the output control device of the present embodiment will be described.The present control device controls the supercharging degree and the motor torque in accordance with the state of charge of the battery to reduce the supercharging loss of the supercharger. The controller 10 includes a supercharging degree adjusting section (supercharging degree adjusting means) 20, a motor / generator torque adjusting section (motor / generator torque adjusting means) 21, and a charged state detecting section (charged state detecting means). The wastegate valve 12, the throttle valve 18, and the motor generator 3 are controlled in accordance with the flowchart shown in FIG. 2 based on information from the various sensors 13, 14, 19 and the like.
[0021]
Hereinafter, the control performed by the supercharging degree adjustment unit 20, the motor / generator torque adjustment unit 21, and the charge state detection unit 22 will be specifically described with reference to the flowchart shown in FIG. Note that this process is a subroutine subordinate to the main routine processed inside the controller 10, so that the process is repeated as appropriate.
[0022]
In step S10, first, a power plant required torque (T _tq ) is determined from information on the accelerator opening by the accelerator pedal stroke sensor 13 and the engine speed (N _e ) by the engine speed sensor 14 using a correspondence map (not shown). I do.
In the next step S20, it is determined whether or not the battery charge detected by the charge state detector 22 is greater than a predetermined value. This predetermined value is referred to as a motor assistable charge amount, and this value is preset based on a map (not shown) as an index indicating a charge amount sufficient to operate the motor / generator by the motor. If the battery charge is equal to or greater than the motor assistable charge, the process proceeds to step S30.
[0023]
In step S30, the supercharging degree adjusting unit 20 is controlled to open the waste gate valve 12 and reduce the supercharging degree.
In the next step S40, it is determined whether or not the power plant required torque (T _tq ) obtained in step S10 is larger than the maximum engine generated torque (T _em ) when the _wastegate is opened. The engine maximum generated torque when the _wastegate is open (T _em ) represents the maximum value of the torque that can be generated by the engine 2 when the wastegate valve 12 is open. If (T _tq )> (T _em ), the process proceeds to step S50, and the motor required torque (T _qm ) for driving the motor / generator 3 and adding it to the engine torque is calculated according to the following equation. The motor generator 3 is controlled by the controller 10 so as to output the required motor required torque (T _qm ).
[0024]
_{(T qm) = (T tq} ) - (T em) ··· (1)
T _qm: required motor torque _{T tq:} Power plant required torque _{T em:} at the maximum opening wastegate when the engine torque and the step S60, the engine required torque _{(T qe),} when open wastegate maximum engine torque _{(T em)} Is set, and the engine 2 is controlled by the controller 10 so as to output the set engine required torque (T _qe ), and this routine ends.
[0025]
If (T _tq ) ≦ (T _em ) in step S40, the process proceeds to step S70, where the power plant required torque (T _tq ) is set as the engine required torque (T _qe ), and the set engine is set. The engine 2 is controlled by the controller 10 so as to output the required torque (T _qe ), and this routine ends.
On the other hand, if the battery charge is less than the motor assistable charge in step S20, the process proceeds to step S80 because the motor assist is not performed.
[0026]
In step S80, the required motor torque (T _qm ) is set to 0, and the motor / generator torque adjusting unit 21 is controlled so as not to perform the motor assist.
Then, in the next step S90, the power plant required torque (T _tq ) obtained in step S10 is compared with the _wastegate opening determination torque. The wastegate opening determination torque is a value set in advance on a map (not shown) in order to open and close the wastegate valve 12 based on the determination of whether the torque can be output even when the wastegate valve 12 is open. is there. If (T _tq ) is smaller than the _wastegate opening determination torque, the process proceeds to step S100, where the supercharging degree adjusting unit 20 is controlled to open the _wastegate valve 12, and the process proceeds to step S70.
[0027]
If (T _tq ) is _{equal to} or greater than the _wastegate opening determination torque in step S90, the process proceeds to step S110, in which the supercharging degree adjusting unit 20 is controlled to close the _wastegate valve 12, and the process proceeds to step S70.
Then at step S70, the set power plant required torque as an engine required torque _{(T qe) (T tq)} is, to output the set required engine torque _{(T qe),} the engine 2 is controlled by the controller 10, This routine ends.
[0028]
With the above-described control, according to the present invention, the following operation and effect can be obtained. Hereinafter, the operation and effect of the present control device will be described with reference to FIGS.
As shown in the diagram showing the basic control on the engine load when the engine speed is kept constant in the present control device of FIG. 3, the amount of charge detected by the charge state detection unit 22 of the controller 10 can be motor assisted. When the charge amount is equal to or more than the charge amount, the wastegate valve 12 is always opened by the supercharging degree adjusting unit 20 as shown by the thick solid line in the figure. Therefore, supercharging by the supercharger is scarcely performed, and supercharging loss is eliminated, so that the fuel consumption rate of the engine 2 is generally reduced and fuel efficiency is improved. When it is determined that the power plant required load is large and the engine torque alone cannot cover the power plant required torque (T _tq ), the motor / generator torque adjusting unit 21 outputs the power plant required torque (T _tq). ) And the maximum engine generated torque (T _em ) when the _wastegate valve is opened and set as the required motor torque (T _qm ), and the motor / generator 3 outputs an output corresponding to the required motor torque (T _qm ). _Is generated, it is possible to accurately output a torque corresponding to the power plant required torque (T _tq ) as a whole.
When the motor / generator 3 operates with the required motor torque (T _qm ), the fuel consumption rate of the engine 2 is further reduced, and the fuel efficiency is improved.
[0029]
On the other hand, when the charge amount detected by the charge state detection unit 22 is less than the motor assistable charge amount, as shown by the thin solid line in the figure, the motor generator 3 does not add the motor torque. However, by comparing the _wastegate valve opening determination torque with the power plant required torque (T _tq ), if supercharging by the supercharger is not necessary, the supercharge degree adjusting unit 20 opens the _wastegate valve 12. , The supercharging loss is eliminated, the fuel consumption rate of the engine 2 is reduced, and the fuel efficiency is improved. Further, when supercharging by the supercharger is necessary, the supercharging degree adjusting unit 20 closes the wastegate valve 12 and performs the conventional control. Therefore, it is necessary to secure sufficient torque by increasing the supercharging pressure. Can be.
[0030]
Further, as shown in the diagram showing the relationship between the engine speed and the power plant torque in the present control device in FIG. 4, in the case of a naturally-supplied engine in which the wastegate valve 12 is fully opened and supercharging is not performed by the supercharger. , The power plant torque changes in a mountain-like manner as indicated by a broken line A with respect to the engine speed.
On the other hand, in the present control device, when the charge amount detected by the charge state detection unit 22 is low, the supercharging degree adjusting unit 20 closes the wastegate valve 12 to perform supercharging. The torque is controlled to generally exceed the broken line A as shown by the thin solid line B. When the charge amount detected by the charge state detection unit 22 is high, the motor / generator torque adjustment unit 21 drives the motor / generator 3 by a motor. In a state where the engine speed is low, the torque is controlled to greatly exceed the thin solid line B.
[0031]
Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and can be variously modified and implemented without departing from the gist of the present invention.
For example, in the above embodiment, the supercharging degree adjusting section (supercharging degree adjusting means) adjusts the supercharging degree only by opening and closing the wastegate valve attached to the supercharger. The degree adjusting section (supercharging degree adjusting means) may be configured so that the opening degree of the wastegate valve can be adjusted to several levels. Specifically, the supercharging degree adjusting unit (supercharging degree adjusting means) sets the wastegate valve opening in several stages according to the magnitude of the battery charge amount in the processing of steps S20 to S30 in FIG. Open. Similarly, in the processing of steps S90 to S100 in FIG. 2, the wastegate valve opening in several stages is set and opened according to the magnitude of the power plant required torque. By doing so, it is possible to suppress the consumption of battery power while improving the fuel consumption rate, and it is possible to apply torque to the engine by the motor for a longer time.
[0032]
Further, a variable capacity supercharger is used instead of the supercharger provided with the wastegate valve in the above-described embodiment, and the supercharge degree adjusting unit (supercharge degree adjusting means) adjusts the capacity of the variable capacity supercharger. The supercharging degree may be adjusted by changing it. With this configuration, the present invention can be applied to a hybrid vehicle having an engine provided with a conventional variable-capacity supercharger, and similar effects can be obtained.
[0033]
【The invention's effect】
As described in detail above, according to the output control device for a hybrid vehicle of the present invention, when the charge amount of the battery is sufficient, the assist by the motor and the supercharge by the supercharger are not performed. Therefore, the supercharging loss can be eliminated, and the fuel efficiency corresponding to the supercharging loss can be improved while securing a sufficient torque. When the charge amount of the battery is not sufficient, control is performed to increase the degree of supercharging of the supercharger, so that sufficient torque by the supercharger can be secured.
[0034]
Further, according to the output control device for a hybrid vehicle of the present invention described in claim 2, the effect of claim 1 can be obtained by opening and closing a general wastegate valve to adjust the degree of supercharging. .
According to the third aspect of the present invention, the effect of the first aspect can be obtained by adjusting the degree of supercharging using a general variable-capacity supercharger. it can.
[0035]
Further, according to the output control device for a hybrid vehicle according to the present invention, it is possible to prevent the state of charge from further lowering.
According to the output control device for a hybrid vehicle of the present invention, when the engine torque is less than the required torque, the shortage is supplemented by the motor torque of the motor / generator, while the required torque is obtained only by the engine torque. Is obtained, the addition of the motor torque is not performed, so that the required torque can always be secured while obtaining the effects of claims 1 to 4.
[0036]
Further, according to the output control device for a hybrid vehicle of the present invention, when the torque by the supercharger is required, the degree of supercharging can be increased to secure a sufficient torque. When the torque by the machine is not required, the degree of supercharging can be reduced to improve the fuel efficiency corresponding to the supercharging loss. Further, the degree of supercharging can be adjusted to an appropriate degree according to the situation.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of an output control device for a hybrid vehicle according to an embodiment of the present invention.
FIG. 2 is a flowchart showing control judgment of an output control device for a hybrid vehicle according to an embodiment of the present invention.
FIG. 3 is a diagram showing a control action on an engine load of the output control device for the hybrid vehicle according to the embodiment of the present invention.
FIG. 4 is a diagram showing a torque control operation of the output control device for the hybrid vehicle according to the embodiment of the present invention.
FIG. 5 is a diagram showing basic control on engine load in a conventional hybrid vehicle output control device.
[Explanation of symbols]
Reference Signs List 1 hybrid vehicle 2 engine 3 motor / generator 10 controller (output control device)
12 Wastegate valve 15 Turbocharger (supercharger)
20 Supercharging degree detector (supercharging degree adjusting means)
21 Motor / generator torque adjustment unit (motor / generator torque adjustment means)
22 Charge state detection unit (charge state detection means)

Claims (6)

An engine provided with a supercharger, and a motor generator having both a function as an electric motor for assisting the driving force of the engine and a function as a generator for charging a battery using the driving force of the engine. In the output control device of the hybrid vehicle equipped with
Charge state detection means for detecting a charge state of the battery;
Supercharging degree adjusting means for adjusting the supercharging degree of the supercharger,
Motor / generator torque adjusting means for adjusting the motor / generator torque,
When the state of charge of the battery detected by the state-of-charge detection means is equal to or greater than a predetermined value, the supercharge degree adjusting means reduces the supercharge degree of the supercharger and the motor / generator torque adjust means Drive the motor generator to add the motor torque to the engine torque,
When the state of charge of the battery detected by the state-of-charge detection means is less than a predetermined value, the supercharge degree adjusting means increases the supercharge degree of the supercharger, wherein the output control of the hybrid vehicle is performed. apparatus. 2. The hybrid vehicle output control device according to claim 1, wherein said supercharging degree adjusting means adjusts a supercharging degree of said supercharger by opening and closing a wastegate valve. The supercharger is a variable capacity supercharger, and the supercharge degree adjusting means adjusts the supercharge degree of the supercharger by changing the capacity of the supercharger. 2. The output control device for a hybrid vehicle according to claim 1. 4. The motor / generator torque adjusting means does not drive the motor / generator when the state of charge of the battery detected by the state of charge detecting means is less than a predetermined value. 2. The output control device for a hybrid vehicle according to claim 1. When the state of charge of the battery detected by the state-of-charge detection means is equal to or greater than a predetermined value, the motor-generator torque adjustment means drives the motor-generator to a motor, and adjusts the magnitude of the difference between the required torque and the engine torque. The output control device for a hybrid vehicle according to any one of claims 1 to 4, wherein a motor torque is added in accordance with the output. 6. The supercharger according to claim 1, wherein the supercharger adjusts the supercharger according to the required torque when the state of charge of the battery is less than a predetermined value. The output control device for a hybrid vehicle according to any one of the preceding claims.

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