JP6011289B2 - Vehicle driving force control device - Google Patents

Description

The present invention relates to a device for controlling the driving force of a vehicle equipped with an internal combustion engine as a driving force source, and particularly to a device for controlling the driving force when an acceleration request is made.

An internal combustion engine (hereinafter referred to as an engine) is widely used as a driving force source for a vehicle, and recently, an engine and a motor have come to be used together as a driving force source. In any of these types of vehicles, the engine output is controlled to meet drive requirements and to improve fuel economy as much as possible. On the other hand, the rotation speed of the engine can be controlled by the gear ratio of the transmission connected to the output side, and recently, a continuously variable transmission that can change the gear ratio steplessly has been used. The engine speed is controlled to a speed that improves fuel efficiency. Further, even in a hybrid vehicle in which the engine speed can be continuously changed by a motor or a motor generator, the engine speed is controlled to a speed at which fuel efficiency is improved.

However, if fuel efficiency is always prioritized as control of the engine speed, for example, when the accelerator pedal is depressed and an acceleration request is made, the increase in the engine speed or its output becomes slow and the feeling of acceleration is felt. It may be impaired. Therefore, for example, the invention described in Patent Document 1 aims to improve the acceleration feeling when a sudden acceleration request is made in a vehicle equipped with a continuously variable transmission and to secure a sufficient driving force. , Accelerate by executing downshift during acceleration to increase the target input rotation speed of the continuously variable transmission by a predetermined amount, and when the input rotation speed reaches the upper limit rotation speed according to the amount of depression of the accelerator pedal, the target input rotation speed Control is performed to reduce the number by a predetermined amount, and such an increase in the target input rotation speed and a decrease in the rotation speed when the input rotation speed reaches the above upper limit rotation speed are repeatedly performed.

Japanese Unexamined Patent Publication No. 2004-125072

In the device described in Patent Document 1 above, when a sudden acceleration request is made, the input rotation speed is increased once, but the target input rotation speed is decreased after the input rotation speed reaches the upper limit rotation speed. , The engine speed corresponding to the input speed increases once and then decreases. The feeling of acceleration that the driver has is obtained not only from the acceleration felt but also from the engine sound, so if the engine speed is increased or decreased as described above, even if the feeling of acceleration can be obtained at the initial stage of acceleration, immediately after that, Since the output torque decreases together with the engine speed, the feeling of acceleration may decrease or may not be obtained.

Such a situation is the same in a hybrid vehicle in which the engine speed can be controlled by a motor and a vehicle equipped with a continuously variable transmission capable of continuously changing the gear ratio. That is, in this type of vehicle, taking advantage of the fact that the engine speed can be controlled by a motor or a continuously variable transmission, the speed at the operating point with good fuel efficiency is set as the target speed, and the target speed and the actual speed are combined. The engine speed is feedback-controlled based on the deviation. Therefore, if the target rotation speed is set based on the acceleration request and the engine speed overshoots in the process of reaching the target rotation speed, the engine speed is set based on the newly generated rotation speed deviation. It will be lowered. The overshoot of the actual engine speed may also occur when the engine speed is decreased, and as a result, the increase control and the decrease control of the engine speed are repeatedly generated, and the decrease control is performed to impair the feeling of acceleration. There is a possibility that

The present invention has been made by paying attention to the above technical problems, and is a driving force control device configured to perform feedback control for making an engine speed follow a target speed, and there is a demand for acceleration. It is an object of the present invention to provide a driving force control device that does not impair the feeling of acceleration in the case of such a case.

To achieve the above object, according to claim 1 invention, the engine based on the acceleration demand in a vehicle engine and a motor or the motor-generator is equipped with a hybrid drive device which are connected by the power distribution mechanism setting a target rotational speed, and the target speed and the actual rotation speed with the actual rotational speed of the engine is feed-forward control torque of the motor so as to change to follow the pre-Symbol target speed the feedback control torque of the motor or the motor generator on the basis of the deviation, in the driving force control apparatus for vehicles, in the case includes an electronic control unit, the electronic control unit, there is an acceleration request, the acceleration The engine rotation speed threshold is set based on the acceleration request amount so as to satisfy the requirement, and when the engine rotation speed increased based on the acceleration request exceeds the engine rotation speed threshold, the engine rotation speed is targeted. without feedback control for the motor or the motor generator torque Ru to follow the rotational speed, to set the rotational speed of the above rotational speed of the actual rotational speed exceeds the target speed of the engine the motor or it is characterized in that it is configured to perform feedforward control of the torque of the motor generator.

According to a second aspect of the invention, in the invention of claim 1, wherein the engine speed threshold value, the constant rotation speed at the order Toe large increase the rotational speed of the Sadamari based on the acceleration demand and pre-SL engine, the design a driving force control apparatus for a vehicle, characterized in that a rotational speed obtained by adding a value where determined.

In the driving force control device according to the present invention, the target rotation speed of the engine is set according to the required drive amount, and the actual rotation speed of the engine changes according to the target rotation speed of the motor or the motor generator. performing feedforward control and feedback control of the torque. Therefore, when there is an acceleration request, the target rotation speed is set according to the request, and the actual rotation speed of the engine is increased accordingly. Further, the engine speed threshold value is set based on the acceleration request amount. Then, actual rotational speed of the engine, the feedforward torque of the motor or the motor-generator so that the target speed based on the acceleration demand control and feedback system the actual rotational speed of the engine in the course of increasing size by control is engine When the number of revolutions exceeds the threshold, the feedback control is not performed, and the actual number of revolutions of the engine is set to a number equal to or higher than the number of revolutions exceeding the threshold of the engine. Incidentally, the engine speed threshold value is set based on the acceleration demand to meet the acceleration demand, therefore it is possible to close the rotational speed to the target engine rotational speed that is set based on the acceleration demand. Therefore, it is avoided or suppressed that the actual engine speed is reduced in the process of increasing the engine speed based on the acceleration request, so that the engine speed does not decrease and the engine torque does not decrease accordingly. , It is possible to avoid or suppress that the feeling of acceleration is impaired.

Further, according to the present invention, since the feedback control is stopped and the actual rotation speed of the engine is controlled as described above by the feedforward control, the rotation speed exceeding the engine rotation speed threshold is not lowered or the target rotation speed is not reduced. Since the actual number of revolutions can be increased according to the increasing gradient of, the feeling of acceleration is improved.

According to the present invention, it is possible to improve the acceleration responsiveness or the feeling of acceleration of the hybrid vehicle.

It is a flowchart for demonstrating an example of the control executed by the driving force control device which concerns on this invention. It is a time chart which shows the change of the engine speed when the control shown in FIG. 1 is performed. It is a block diagram which shows typically an example of the vehicle to which this invention can apply. It is a skeleton diagram for demonstrating the hybrid drive device. It is a block diagram for demonstrating the basic control of the hybrid drive device.

The vehicle targeted by the present invention is provided with an engine such as a gasoline engine or a diesel engine as a driving force source, and is configured so that the rotation speed of the engine can be continuously changed and controlled to an appropriate rotation speed. There is. Such control of the number of revolutions can be performed by a so-called continuously variable transmission mechanism, and a specific example of the continuously variable transmission mechanism is a continuously variable transmission such as a belt type or a toroidal type, or an engine and a motor. Alternatively, it is a hybrid drive device in which a motor / generator is connected by a power distribution mechanism including a differential mechanism. In the following specific example, an example applied to a hybrid vehicle will be described. FIG. 3 is a schematic block diagram of the hybrid drive system, in which the engine 1 is connected to the hybrid drive device 2 and the power output from the hybrid drive device 2 is transmitted to the drive wheels 3 to travel. Has been done.

FIG. 4 schematically shows an example of the hybrid drive device 2, and the example shown here includes two motors, a first motor generator (MG1) 4 and a second motor generator (MG2) 5. It is a so-called two-motor type device equipped. In order to control the rotation speed of the engine 1 by the first motor generator 4, the first motor generator 4 and the engine 1 are connected to a power distribution mechanism 6 composed of a differential mechanism. The power distribution mechanism 6 includes a sun gear 7, a ring gear 8 arranged concentrically with respect to the sun gear 7, and a carrier 9 holding a pinion gear that meshes with the sun gear 7 and the ring gear 8 to rotate and revolve. It has. The carrier 9 is an input element for inputting the power of the engine 1, the sun gear 7 is connected to the first motor generator 4 to be a reaction force element, and the ring gear 8 is directed toward the drive wheels 3. A second motor / generator 5 is connected to the ring gear 9, which is an output element that outputs power. Therefore, this power distribution mechanism 6 causes the first motor / generator 4 to function as a generator or a motor when the engine 1 outputs power and the vehicle is traveling at a constant speed when the vehicle speed is constant. The engine speed can be appropriately controlled by changing the speed of the sun gear 7 to a large or small size. Therefore, the power distribution mechanism 6 and the first motor generator 4 function as a continuously variable transmission mechanism.

Further, each of the motor generators 4 and 5 is electrically connected to a hybrid controller (HV controller) 11 including an inverter and a power storage device, and power is supplied from the power storage device to any of these motor generators 4 and 5. The electric power generated by supplying and functioning as a motor or by operating any of these motor generators 4 and 5 as a generator is charged to the power storage device, and the electric power generated by the first motor generator 4 is used as the first. 2 It is configured to supply to the motor generator 5.

A hybrid drive device 2 including the above motor generators 4 and 5, an HV controller 11, and an electronic control device (ECU) 12 for controlling the engine 1 are provided. The electronic control device 12 is mainly composed of a microcomputer, performs calculations using various input data and data stored in advance, and uses the result of the calculation as a control command signal for the engine 1 and the hybrid drive device. It is configured to output to 2 or the HV controller 11. The input data is a detection signal (engine rotation speed) by the engine rotation speed sensor 13, an accelerator opening degree (drive request amount) by the accelerator opening degree sensor 14, a vehicle speed, and the like.

The basic control or steady control of the hybrid drive device 2 is shown in a block diagram in FIG. The required driving force F is obtained based on the accelerator opening PAP and the vehicle speed V while traveling at a predetermined accelerator opening PAP. The required driving force F can be obtained from a map prepared in advance. Then, the target output Pt of the engine 1 is calculated based on the required driving force F and the vehicle speed V. On the other hand, the target engine speed NEt is calculated based on the target output Pt. This can be obtained as the number of revolutions of the operating point that outputs the target output Pt with the optimum fuel consumption, and a map prepared in advance can be used. On the other hand, the target throttle opening θth, which is the target engine torque, is obtained from the target engine speed NEt and the target output Pt. Then, the torque or the rotation speed of the first motor generator 4 is controlled so that the actual rotation speed of the engine 1 becomes the above-mentioned target engine rotation speed NEt, and the control is performed by the target engine rotation speed NEt and the actual engine rotation speed. It is performed by feedback control based on the deviation of. When an acceleration operation such as depressing the accelerator pedal is performed, a driving point away from the above-mentioned optimum fuel consumption operating point is transiently set according to the acceleration request, and the operating point is set. Control is performed with the engine speed at the target speed as the target speed. Therefore, the feedforward control value for reaching the target rotation speed is set, and the feedback control is executed so that the actual engine speed matches the target rotation speed.

In the driving force control device according to the present invention, in addition to the fuel consumption priority feedback control shown in FIG. 5, control is executed so as not to impair the feeling of acceleration when an acceleration request is made. An example of the control is shown in a flowchart in FIG. The routine shown in FIG. 1 is repeatedly executed at predetermined short time intervals when an acceleration request such as depression of the accelerator pedal is made. First, the torque TGiner of the first motor generator 4 for satisfying the acceleration request is executed. It is calculated (step S1). This torque TGiner is a torque for increasing the engine speed during the time (cycle time) for repeating the routine of FIG. 1 once. Therefore, the target engine speed increase amount dNEtag is read and used. The operation is performed. Here, the target engine speed increase amount dNEtag is an amount to be increased during the cycle time of the routine of FIG. 1 in the process of increasing to the target speed determined based on the acceleration request. In other words, the target engine speed increase amount dNEtag is a value obtained by converting a predetermined target gradient when increasing the engine speed into an increase amount per cycle time of the routine of FIG. Therefore, since the target engine speed increase dNEtag is an angular acceleration, the torque TGiner of the first motor generator 4 sets the inertia of the first motor generator 4 and the engine 1 to the target engine speed increase dNEtag. It is obtained by multiplying the moments and further multiplying by a conversion coefficient for converting to the shaft torque of the first motor / generator 4.

Then, the torque TGff of the first motor generator 4 when the engine speed is increased by feedforward control is obtained (step S2). This is the base value TGbase, which is the torque of the first motor generator 4 required to maintain the engine speed at that time, and the engine speed obtained in the above step S1 during one cycle time. It can be obtained by adding the TGiner for the torque increase of the first motor / generator 4 required for the increase. Therefore, the torque increase TGiner obtained here corresponds to the torque that increases the engine speed with a predetermined gradient based on the acceleration request.

Then, the operation determination of the feedback control of the engine speed is performed (step S3). This determination is a determination as to whether or not to execute feedback control of the engine speed, and when the drive request amount is large, that is, when the acceleration request is large, the feedback control is performed so as not to impair the feeling of acceleration. It is for determining the cancellation. Specifically, it is determined whether or not the engine speed NE is larger than the predetermined threshold value NEsh. The engine speed threshold NEsh is the process of increasing the engine speed NE based on the acceleration request, and the degree of increase in the engine speed NE is insufficient for the acceleration request, or the engine speed NE decreases. It is a value to be set in order to avoid such a situation, and can be predetermined as a value according to the acceleration request amount based on an experiment or a simulation from these viewpoints. Specifically, the rotation speed can be obtained by adding a predetermined value determined in the design to the increase amount of the engine rotation speed NE that can be determined based on the acceleration requirement amount.

When the target engine speed is set based on the acceleration request, the feedback control is executed at that time, so the engine speed NE is increased according to the deviation between the target value and the actual value of the engine speed NE. Control is executed. In the vehicle equipped with the hybrid drive device 2 described above, the torque TGfb of the first motor generator 4 required to increase the engine speed NE is calculated (step S4). The relationship of torque of each rotating element in the differential mechanism constituting the power distribution mechanism 6 described above is geometrically based on the gear ratio (ratio of the number of teeth of the sun gear 7 to the number of teeth of the ring gear 8) and the like. Therefore, the torque TGfb of the first motor generator 4 can be obtained by using this. Then, as the torque command value TG of the first motor / generator 4, the value obtained by adding the torque TGff by the feedforward control obtained in the above step S2 and the torque TGfb by the feedback control obtained in the step S4 is obtained. (Step S5). This is normal control.

On the other hand, when a positive judgment is made in step S3 above, that is, when the engine speed NE exceeds the threshold value NEsh, the feedback control for bringing the actual engine speed to or close to the target speed is stopped (step S6). .. Specifically, in this control, the torque TGfb of the first motor generator 4 obtained by the rotation speed feedback control based on the deviation between the actual engine speed and the target rotation speed is set to "0" regardless of the calculated value by the feedback control. It is done by setting. Then, the process proceeds to step S5 described above, and therefore, the torque TG of the first motor generator 4 obtained in this case becomes the value TGff only by the feedforward control because the value TGfb by the feedback control is “0”. Become.

The change in engine speed NE when the control shown in FIG. 1 is performed is shown in the time chart in FIG. 2. In the example shown here, the accelerator pedal is returned and the opening degree becomes "0". This is an example of the case where the accelerator pedal is depressed and accelerates from the state where the accelerator pedal is depressed, and when the accelerator pedal is depressed at the time of T1 and the opening degree exceeds the threshold value PAP0 for determining whether the feedback control is executed or not executed. The target engine speed NE and the above-mentioned threshold value NEsh for the engine speed are set based on the accelerator opening. Along with this, feedback control is executed so that the actual engine speed NE matches or approaches the target speed, and the feedback control amount (F / B torque) of the first motor generator 4 increases. Further, feedforward control is executed so as to raise the actual engine speed to the target speed, and a feedforward control amount (F / F torque) for increasing the torque of the first motor generator 4 is obtained.

By executing such feedforward feedback control for the first motor generator 4, the actual engine speed gradually increases. In the process, the increasing gradient of the target engine speed becomes gentle, so that the torque value (F / F torque) by the feedforward control is reduced accordingly. Then, when the actual engine speed NE reaches the threshold value NEsh described above (at the time of T2), the feedback control is stopped and the control amount (F / B torque) is set to "0". That is, the control to match or bring the actual engine speed to or close to the target speed is no longer performed, and the above-mentioned threshold NEsh for the engine speed is the amount of increase (raise amount) of the engine speed determined based on the acceleration request amount. ) With a predetermined value determined by design, the actual engine speed does not decrease toward the target speed, and is set to the above threshold NEsh or a speed higher than the target speed. Be maintained.

As described above, the control amount by the feedforward control is the amount obtained by adding the TGiner for the increase in the engine speed to the base value TGbase. Therefore, the feedback control is stopped and the feedforward control is continued, so that the actual engine speed is rotated. The number increases with a gradient equal to or close to the increasing gradient of the target rotation speed. Then, when the accelerator pedal is returned and the opening degree is reduced toward "0", and in the process becomes the threshold value PAP0 or less for the accelerator opening degree (at T3), the target rotation speed rotates according to the accelerator opening degree. The number is reduced to the number, and the feedback control is restarted, so that the feedback control amount and the feedforward control amount of the first motor generator 4 are reduced to the negative control amount.

As described above, according to the control device according to the present invention, when there is an acceleration request, the engine speed is increased so as to satisfy the acceleration request, and in the process, the actual engine speed is a predetermined value close to the target speed. When the value (threshold) is exceeded, the feedback control for bringing the actual engine speed to or close to the target speed is stopped. As a result, according to the driving force control device of the present invention, the actual engine speed does not decrease after the actual engine speed exceeds the target speed during acceleration, so that the feeling of acceleration is not impaired. Alternatively, it can be suppressed.

1 ... Engine, 2 ... Hybrid drive unit, 3 ... Drive wheel, 4 ... 1st motor generator (MG1), 6 ... Power distribution mechanism, 7 ... Sun gear, 8 ... Ring gear, 9 ... Carrier, 11 ... Hybrid controller (HV) Controller), 12 ... Electronic control device (ECU).

Claims (2)

Sets a target rotational speed of the engine based on the acceleration demand in a vehicle engine and a motor or the motor-generator is equipped with a hybrid drive device which are connected by the power distribution mechanism, the actual rotation speed of the engine is before serial the actual speed and the deviation feedback system the torque of the motor or the motor-generator based on the target rotational speed as well as feed-forward control torque of the motor so as to change to follow the target rotational speed to control, the driving force control apparatus for vehicles,
Equipped with an electronic control device
When an acceleration request is made, the electronic control device sets an engine speed threshold based on the acceleration request amount so as to satisfy the acceleration request, and the engine speed increased based on the acceleration request is the engine speed. If it exceeds the engine speed threshold value, without performing the feedback control for the torque of the motor or the motor generator Ru to follow the rotational speed of the engine to the target rotational speed, the target rotation the actual rotational speed of the engine driving force control apparatus for a vehicle, characterized in that it is configured to perform feedforward control of the torque of the motor or the motor-generator to set the rotational speed of the above rotational speed exceeds the number. Wherein the engine speed threshold value, the acceleration request based Sadamari and a constant rotational speed at the order Toe large increase the rotational speed of the front SL engine, a rotational speed obtained by adding the value at that defines the design The vehicle driving force control device according to claim 1.

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