JP2004316502A - Control device for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the blow-up of an engine speed and an increase in drive torque. <P>SOLUTION: A power-generation quantity is determined by SOC calculated by an SOC calculation section 21, and the quantity and the present motor rotational speed are delivered to a power generation engine torque calculation section 22, and the power generation quantity is converted into torque from the present motor rotational speed. Engine torque for travelling obtained by the power generation engine torque calculation section and a travelling engine torque calculation section 23 is added and given to an engine torque command value calculation section 25, thus commanding toque to an engine 1. Throttle opening correction torque and engine torque for power generation after the correction are calculated by a torque correction calculation section 26 by the engine torque for power generation and an estimated motor rotational speed, and the throttle opening correction torque is subtracted from the engine torque to subtract excessive torque. The engine torque for power generation is determined by obtaining the correction value of the corrected engine torque for power generation in consideration of rotation control. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hybrid vehicle control device including an engine and a motor.
[0002]
[Prior art]
In a conventional hybrid vehicle including an engine and a motor, when the state of charge (SOC) of the battery is equal to or lower than a predetermined value, the engine operates the motor as a generator to generate power. To charge. At this time, the engine outputs a torque obtained by adding the torque for driving the vehicle corresponding to the accelerator operation amount operated by the driver and the torque for generating the motor.
[0003]
[Patent Document 1]
JP 2000-115908 A
[Problems to be solved by the invention]
As described above, in the conventional hybrid vehicle, when charging the battery, the engine outputs a torque obtained by adding the generated torque for generating the motor and the driving torque for running the vehicle. Was.
[0005]
However, since the motor has an output characteristic in which the torque that can be generated is reduced when the rotation speed exceeds a certain rotation speed, when the engine (= motor) is rotating beyond the certain rotation speed, the power generation torque output by the engine is reduced. Cannot be completely absorbed by the motor.
[0006]
For this reason, the power generation torque that could not be absorbed is added to the drive torque, and the engine speed is increased and the drive power is increased, which may give a passenger an uncomfortable feeling.
[0007]
The present invention has been made in view of such a problem, and restricts the engine torque to an additional torque that can be absorbed by the motor, thereby preventing the engine speed from rising and increasing the driving torque of the vehicle. An object of the present invention is to prevent an occupant from feeling uncomfortable by preventing such a situation.
[0008]
[Means for Solving the Problems]
The present invention is a hybrid vehicle including an engine and a motor,
The engine is controlled by the engine control means so as to output an added torque obtained by adding the power generation torque and the driving torque,
The motor calculates the torque that can be generated by the calculation means,
The engine control means is configured to subtract the correction torque corresponding to the surplus torque obtained by subtracting the power generation torque from the power generation torque from the addition torque and output the correction torque to the engine.
[0009]
【The invention's effect】
According to the present invention, since the addition torque is limited to the amount that can be absorbed by the motor, the engine speed does not increase, the driving torque does not increase, and the occupant does not feel uncomfortable.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system configuration diagram showing a schematic configuration of a hybrid vehicle control device according to the present invention. This hybrid vehicle has a motor / generator (hereinafter referred to as a motor) 2 connected to an engine 1. As the motor 2, a three-phase AC motor is used, and the motor 2 is charged and discharged with a battery 5 via an inverter 4.
[0011]
When the driving force of the vehicle is assisted by the motor 2 or when the engine 1 is started, the DC power charged in the battery 5 is supplied to the motor 2 so that the motor 2 runs. The motor 2 generates electric power by being rotated by the engine 1, and charges the electric power to the battery 5.
[0012]
Reference numeral 8 denotes a resolver that detects the number of revolutions of the motor 2, and the number of revolutions of the motor 2 detected by the resolver 8 is input to the controller 3. In the present embodiment, since the rotation speed of the engine 1 and the rotation speed of the motor 2 are the same, the motor rotation speed detected by the resolver 8 is the same as the engine rotation speed. It becomes.
[0013]
The battery 5 is provided with a current sensor 6 for detecting a charge / discharge current flowing through the battery 5 (hereinafter referred to as a battery current) and a voltage sensor 7 for detecting a voltage between terminals of the battery 5 (hereinafter referred to as a battery voltage). ing. The battery current detected by the current sensor 6 and the battery voltage detected by the voltage sensor 7 are output to the controller 3, and the controller 3 uses the battery current and the battery voltage to determine the state of charge (State Of Of) of the battery 5. Charge).
[0014]
The controller 3 is connected to an accelerator opening sensor 10 for detecting the accelerator opening, and receives the accelerator opening detected by the accelerator opening sensor 10.
[0015]
The controller 3 calculates the torque of the engine 1 using the motor rotation speed detected by the resolver 8, the accelerator opening detected by the accelerator opening sensor 10, the calculated battery SOC, and the like, and opens the throttle based on the engine torque. The throttle valve 9 is controlled based on the throttle opening.
[0016]
The controller 3 includes a CPU, a ROM, a RAM, an input / output interface, and the like.
[0017]
The controller 3 also calculates a command value for each actuator (not shown). Note that a controller may be provided for each actuator, and a command value to each actuator may be calculated. Outputs of the engine 1 and the motor 2 are transmitted to an axle 12 via a transmission mechanism 11.
[0018]
In the above embodiment, a system in which the engine 1 and the motor 2 are arranged on the same axis has been described. However, a system in which the engine 1 and the motor 2 are interlocked via a crank pulley and a belt may be used. It is sufficient that the engine 1 generates power from the motor 2.
[0019]
FIG. 2 is a block diagram showing a control function calculated by the controller.
[0020]
In FIG. 2, SOC calculating section 21 calculates the state of charge SOC of battery 5 using the battery current detected by current sensor 6 and the battery voltage detected by voltage sensor 7. The SOC is calculated by accumulating and integrating the battery current detected by the current sensor 6, or by performing a regression calculation on the battery voltage and the battery current to calculate the battery voltage at no load. There is a method of calculating from the correlation with the SOC.
[0021]
The SOC of the battery 5 calculated by the SOC calculation unit 21 is output to the necessary power generation amount calculation unit 29. The required power generation amount calculation unit 29 converts the battery SOC output from the SOC calculation unit 21 into a map shown in FIG. By comparing them, the required power generation amount tpw1 is calculated, and the required power generation amount tpw1 is output to the generated engine torque calculation unit 22.
[0022]
As shown in FIG. 3, the required power generation amount tpw1 is set to be a constant power generation amount (for example, 20 [kw]) when the battery SOC is 60% or less, and when the SOC exceeds 60%, the required power generation amount tpw1 is set. tpw1 is set so as to gradually decrease, and when the SOC is 100%, the required power generation amount is set to be 0 [kw], so that the charge amount of the battery 5 is kept in a certain range.
[0023]
The correlation between the SOC shown in FIG. 3 and the required power generation amount tpw1 is stored in the controller 3 in advance.
[0024]
The power generation engine torque calculation unit 22 calculates the power generation engine torque tpw based on the required power generation amount tpw1 output from the required power generation amount calculation unit 29 and the rotation speed of the motor 2 detected by the resolver 8, and calculates the power generation engine torque tpw. The minute engine torque tpw is output to the adder 24 and the torque correction calculator 26.
[0025]
If the generated engine torque tpw calculated by the generated engine torque calculation unit 22 cannot be absorbed by the motor-capable torque tgn of the motor 2, a margin for controlling the rotation speed of the motor 2 will be described later. The corrected power generation engine torque tpw ′ output from the torque correction calculation unit 26 is used as the power generation engine torque tpw and output to the addition unit 24. The details will be described later.
[0026]
The running engine torque calculator 23 calculates the running engine torque tern based on the accelerator opening of the engine 1 detected by the accelerator opening sensor 10 and outputs the calculated engine torque tern to the adder 24.
[0027]
The adder 24 adds the generated engine torque tpw output from the generated engine torque calculator 22 and the running engine torque tern output from the running engine torque calculator 23 to the engine torque teng (= tpw + tern). Is output to the engine torque command value calculation unit 25.
[0028]
The engine torque command value calculator 25 calculates a command value such as an ignition timing or a fuel injection amount of the engine 1 based on the engine torque teng output from the adder 24 and the rotation speed of the motor 2 detected by the resolver 8. Is determined, and the engine 1 is controlled. The engine torque command value calculation unit 25 outputs the engine torque teng input from the addition unit 24 to the subtraction unit 27.
[0029]
The torque correction calculator 26 receives the power generation engine torque tpw from the power generation engine torque calculator 22 and the rotation speed of the motor 2 detected by the resolver 8. The torque correction calculator 26 performs a predetermined process on the input motor rotation speed to estimate the motor rotation speed after a certain time.
[0030]
Based on the estimated motor rotation speed tgn calculated in accordance with the estimated motor rotation speed and the generated engine torque tpw input from the generated engine torque calculation unit 22, the motor generated torque tgn is calculated based on the generated engine torque. When the torque is smaller than the torque, the throttle opening correction torque tsrh is calculated, and the throttle opening correction torque tsrh is output to the subtraction unit 7.
[0031]
Further, when the motor power-producible torque tgn is smaller than the power generation engine torque tpw, the torque correction calculation unit 26 determines the corrected power generation engine torque in order to secure a margin for controlling the rotation speed of the motor 2. tpw ′ is calculated, and the corrected power generation engine torque tpw ′ is output to the power generation engine torque calculation unit 22. The details of the calculation performed by the torque correction calculator 26 will be described later.
[0032]
The subtraction unit 27 calculates a corrected engine torque teng ′ obtained by subtracting the throttle opening correction torque tsrh output from the torque correction calculation unit 26 from the engine torque teng output from the engine torque command value calculation unit 25. Output to the unit 28.
[0033]
The throttle opening calculator 28 converts the corrected engine torque teng ′ output from the subtractor 27 into a throttle opening command value, and controls the opening of the throttle valve 9.
[0034]
The operation of the block diagram of FIG. 2 can be summarized by calculating the SOC of the battery 5 based on the battery voltage and the battery current, calculating the required power generation amount tpw1 corresponding to the SOC, and generating power to obtain the required power generation amount tpw1. The minute engine torque tpw is calculated. On the other hand, the running engine torque tern corresponding to the accelerator opening is calculated.
[0035]
A throttle opening command value for obtaining an engine torque teng obtained by adding the generated engine torque tpw and the running engine torque tern is calculated by the throttle opening calculator 28, and the opening of the throttle valve 9 is controlled. .
[0036]
In this manner, the engine 1 outputs the engine torque teng obtained by adding the running engine torque tern for driving the vehicle and the generated engine torque tpw for generating the motor 2 to charge the battery 5.
[0037]
On the other hand, if the motor-generable torque tgn is smaller than the generated engine torque tpw, the motor 2 cannot absorb (generate) the generated engine torque tpw required to charge the battery 5, and the driving force of the vehicle Becomes larger, so that the surplus is corrected.
[0038]
That is, the throttle opening correction torque terh corresponding to the surplus torque tover corresponding to the difference between the power generation engine torque tpw of the motor 2 and the motor power generation possible torque tgn is subtracted from the engine torque teng to obtain the corrected engine torque teng. ′ Is calculated, and a throttle opening command value for obtaining the corrected engine torque teng ′ is calculated by the throttle opening calculator 28 to control the opening of the throttle valve 9.
[0039]
Further, when the motor power-generating torque tgn is smaller than the power generation engine torque tpw, the corrected power generation engine torque tpw ′ is calculated in order to secure a margin for controlling the rotation speed of the motor 2. The corrected power generation engine torque tpw ′ is output to the power generation engine torque calculation unit 22, and the corrected power generation engine torque tpw ′ is used as the power generation engine torque tpw.
[0040]
FIG. 4 is a flowchart showing a control program executed by the controller 3. Hereinafter, the control program will be described with reference to this flowchart.
[0041]
The process shown in the flowchart of FIG. 4 starts when an ignition switch (not shown) is turned on.
[0042]
First, in step S1, based on the battery current detected by the current sensor 6 and the battery voltage detected by the voltage sensor 7, the SOC calculator 21 shown in FIG. The necessary power generation amount tpw1 is read out by comparing the SOC with the map shown in FIG. 3 by the required power generation amount calculation unit 29, and the required power generation amount tpw1 read by the required power generation amount calculation unit 29 is read out by the power generation engine torque calculation unit 22. Based on the rotational speed of the motor 2 detected by the resolver 8, the generated engine torque tpw is calculated.
[0043]
When the corrected generated engine torque tpw ′ is calculated in step S8 described later, the corrected generated engine torque tpw ′ is used as the generated engine torque tpw. Further, based on the accelerator opening of the engine 1 detected by the accelerator opening sensor 10, the running engine torque tern is calculated. Next, the engine torque teng is calculated by adding the generated engine torque tpw and the running engine torque tern.
[0044]
Next, in step S2, the torque correction calculator 26 estimates the motor rotation speed in the next calculation cycle. This estimates the motor rotation speed in the next calculation cycle from the deviation between the motor rotation speed gn _-1 in the previous calculation cycle and the motor rotation speed gn in the current calculation cycle in consideration of the response delay of the throttle of the engine. Then, control is performed by using the estimated motor rotation speed as the current motor rotation speed, so that the effect of the throttle response delay is reduced as much as possible.
[0045]
Specifically, as shown in FIG. 5, _assuming that the motor rotation speed in the current calculation cycle t is gn and the motor rotation speed in the previous calculation cycle t-1 is gn _-1 , the next calculation cycle t + 1 motor speed _{g n + 1} in is considered to be a _{gn + (gn-g n-} 1), the motor speed _{g n + 1} in the next computation cycle t + 1 is used. As described above, by using the motor rotation speed g _{n + 1} in the next calculation cycle for the calculation, the read-ahead control in consideration of the delay of the throttle response, that is, the feedforward control is performed.
[0046]
Next, in step S3, the motor power generation torque tgn corresponding to the motor rotation speed is read by comparing the motor rotation speed g _{n + 1} calculated in step S2 with the map shown in FIG. As shown in FIG. 6, the motor power generation possible torque tgn can output the maximum power generation possible torque tgn up to a certain rotation speed in a region where the rotation speed is low, but when the rotation speed exceeds the certain rotation speed, It has a characteristic that the power generation possible torque tgn gradually decreases.
[0047]
Next, in step S4, the power generation engine torque tpw calculated in step S1 is compared with the motor power generation possible torque tgn read in step S3. If the power generation engine torque tpw is equal to or smaller than the motor power generation possible torque tgn, the battery 5 is discharged. It is determined that the generated engine torque tpw required for charging can be absorbed by the motor 2 (power generation is possible), and the process returns to the start. On the other hand, in step S4, when the generated engine torque tpw is larger than the motor power-producible torque tgn, the motor 2 cannot absorb (generate) the generated engine torque tpw required to charge the battery 5. Since the rotation speed of the engine 1 increases, the process proceeds to step S5 in order to perform a process for correcting the generated engine torque tpw output by the engine 1 in order to avoid this.
[0048]
In step S5, of the generated engine torque tpw, a surplus torque over that cannot be absorbed by the motor 2 is calculated. As shown in FIG. 6, the surplus torque “over” is calculated by subtracting the motor power generation possible torque tgn calculated in step S3 from the generated engine torque tpw calculated in step S1.
[0049]
Next, in step S6, the throttle opening correction torque tsrh corresponding to the excess torque “over” is read by comparing the excess torque “over” obtained in step S5 with the map shown in FIG. The map shown in FIG. 7 is set such that the throttle opening correction torque tsrh increases quadratically as the excess torque tover increases. Next, the corrected engine torque teng ′ is calculated by subtracting the throttle opening correction torque tsrh from the engine torque teng calculated in step S1, and the throttle opening corresponding to the corrected engine torque teng ′ is calculated. The opening of the throttle valve 9 is controlled so as to achieve this throttle opening.
[0050]
Next, in step S7, when fluctuations in the amount of air flowing into the engine 1 and misfires (misfires) occur to cause fluctuations in the rotational speed of the engine 1, the motor 1 is rotated to suppress fluctuations in the rotational speed. Leave enough power to perform numerical control. This is because not all the motor power-producible torque tgn of the motor 2 calculated in step S3 is used as the power-generating engine torque tpw, but the motor power-producable torque tgn is multiplied by a predetermined rotational speed control coefficient tgp to generate power. The minute engine torque tpw is corrected (reduced).
[0051]
As shown in FIG. 8, the difference between the rotation speeds obtained by subtracting the rotation speed gn of the current calculation cycle from the estimated rotation speed gn _{+ 1 of} the next calculation cycle calculated in step S2 is set on the horizontal axis. A rotation speed control coefficient tgp is set on the shaft, and the rotation speed control coefficient tgp is set to gradually increase as the rotation speed difference increases. As described above, based on the rotation speed difference calculated in step S2, the rotation speed control component coefficient tgp is read out with reference to the map shown in FIG.
[0052]
Next, the motor-controllable torque tgn calculated in step S3 is multiplied by a rotation-control-dependent coefficient tgp to calculate a rotation-control-dependent torque tygn.
[0053]
Next, in step S8, the corrected generated engine torque tpw 'is calculated. The corrected engine torque tpw ′ for the power generation is calculated by subtracting the torque tygn for the rotation speed control calculated in step S7 from the motor power generation possible torque tgn. The engine 1 is controlled so as to generate the generated engine torque tpw having a margin for performing the rotation speed control by using the calculated corrected generated engine torque tpw ′ as the new generated engine torque tpw. Is done.
[0054]
That is, as shown in FIG. 9, the motor power-producable torque tgn is decomposed into a rotational speed control torque tygn and a corrected power-produced engine torque tpw ′, and all the motor power-producable torque tgn is used for the power-generated engine torque tpw. Instead, the corrected power generation engine torque tpw ′ obtained by reducing the rotational speed control torque tygn is used as the power generation engine torque tpw. After calculating the corrected generated engine torque tpw ′ in step S8, the process returns to step S1.
[0055]
As described above, in the present embodiment, the running engine torque tern is calculated based on the accelerator opening detected by the accelerator opening sensor 10, and the generated engine torque tpw is calculated based on the SOC of the battery 5. The engine torque teng, which is obtained by adding the running engine torque tern and the generated engine torque tpw, is output to the engine 1. The generated engine torque tpw is the motor power generating torque tgn that the motor 2 can generate. If the engine torque is larger than the engine torque teng, the engine 1 is controlled so that the throttle opening correction torque tsrh corresponding to the surplus torque tover becomes the corrected engine torque teng ′ obtained by subtracting the engine torque teng. Output engine torque tpw output by the motor 2, it is possible to absorb (power generation), and it is possible to prevent an occupant from feeling uncomfortable due to an increase in engine speed and an increase in driving torque of the vehicle.
[0056]
Further, in the present embodiment, the motor-generable torque tgn of the motor 2 is calculated based on the motor rotation speed in the next calculation cycle estimated from the motor rotation speed in the previous calculation cycle and the motor rotation speed in the current calculation cycle. Since the calculation is performed based on the rotation speed, control can be performed in consideration of the delay in the response of the throttle of the engine 1, and the engine 1 can be further prevented from being blown up.
[0057]
Further, in the present embodiment, instead of using all the power-generating torque tgn of the motor of the motor 2 as the power-generating engine torque tpw, the rotational speed control-dependent torque tygn for performing the rotational speed control from the motor power-generating torque tgn is used. Since the reduced value is used as the generated engine torque tpw, when the rotation speed fluctuates, the rotation speed control is performed using the rotation speed control torque tygn, thereby suppressing the rotation speed fluctuation. can do.
[0058]
In this embodiment, the throttle opening correction torque tsrh is increased as the excess torque tover obtained by subtracting the motor-generating torque tgn of the motor 2 from the generated engine torque tpw increases. When the over is large, the throttle valve 9 can be closed earlier.
[0059]
Further, in the present embodiment, when the difference between the motor rotation speed in the previous calculation cycle and the motor rotation speed in the current calculation cycle is large, the ratio of the rotation speed control component torque tygn used for the rotation speed control is reduced. Since the rotation speed is increased, it is possible to cope with the rotation speed fluctuation when the rotation speed fluctuation occurs.
[0060]
The correspondence between the components of the claims and the configuration of the present embodiment is as follows.
[0061]
The engine 1 constitutes the engine, the motor 2 constitutes the motor, and the controller 3 constitutes the engine control means and the power generation possible torque calculation means.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram showing a schematic configuration of a hybrid vehicle control device according to the present invention.
FIG. 2 is a block diagram showing a control function of a controller.
FIG. 3 is a characteristic diagram showing a required power generation amount with respect to a state of charge SOC.
FIG. 4 is a flowchart showing a control program executed by a controller.
FIG. 5 is a characteristic diagram showing a change in motor rotation speed with respect to time.
FIG. 6 is a diagram illustrating a relationship among a motor rotation speed, a motor-generable torque, a generated engine torque, and a surplus torque.
FIG. 7 is a diagram showing a relationship between surplus torque and throttle opening correction torque.
FIG. 8 is a diagram illustrating a relationship between a deviation of a motor rotation speed and a rotation speed control component coefficient.
FIG. 9 is an explanatory diagram when a motor power-producible torque is used as a generated engine torque.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Motor / generator 3 ... Controller 4 ... Inverter 5 ... Secondary battery (battery)
6 Current sensor 7 Voltage sensor 8 Speed sensor (resolver)
9 Throttle valve 10 Accelerator opening sensor

Claims (5)

In a hybrid vehicle including an engine and a motor,
Power generation torque set according to the state of charge of the battery,
A driving torque for driving the vehicle set by an operator's request,
Engine control means for controlling the engine so that the engine outputs an added torque obtained by adding the power generation torque and the drive torque,
Power generating torque calculating means for calculating the power generating torque that the motor can generate,
With
The engine control means outputs, when the generated torque is greater than the power-generating torque, a correction torque corresponding to a surplus torque obtained by subtracting the power-generating torque from the power-generating torque from the added torque to the engine. A hybrid vehicle control device comprising: The power generation possible torque calculation means calculates the power generation possible torque based on a next motor rotation speed estimated from a difference between a previous motor rotation speed and a current motor rotation speed. The hybrid vehicle control device according to any one of the preceding claims. The power generation possible torque calculation means calculates a torque obtained by subtracting a torque for controlling the rotation speed of the motor from a power generation possible torque determined from the rotation speed of the motor as the power generation possible torque. 3. The hybrid vehicle control device according to 1 or 2. 3. The hybrid vehicle control device according to claim 1, wherein the engine control unit increases the correction torque as the surplus torque increases. 4. 4. The hybrid vehicle control device according to claim 3, wherein a ratio of the torque for controlling the rotation speed of the motor is increased when the deviation is large. 5.

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