JP2016210241A - Control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stop a crank angle at a desirable position while suppressing preferably variations of twist angles of a damper when stopping an internal combustion engine.SOLUTION: The control device of a hybrid vehicle controls the hybrid vehicle equipped with an internal combustion engine which outputs torque to a power transmission portion via a damper, an electric motor which outputs torque to the power transmission portion and crank angle control means which when stopping the internal combustion engine, executes crank angle control by which a crank angle of the internal combustion engine is stopped at a predetermined position. The control device of a hybrid vehicle comprises: torque calculating means S104 that calculates variation suppressing torque which should be outputted from the electric motor in order to reduce variations of twist angles of a damper which occurs when executing the crank angle control; and output control means S107 which compares normal and negative absolute values of the variation control torque with each other (S105), aligns a larger absolute value with a smaller absolute value (S106) and then controls the electric motor so that the variation suppression torque is outputted.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a technical field of a control device for a hybrid vehicle applied to a hybrid vehicle including an internal combustion engine and an electric motor.

  As this type of device, a device for reducing vibration caused by torque fluctuation of an internal combustion engine is known. For example, Patent Document 1 discloses a technique of reducing vibration caused by torque pulsation by outputting torque having an opposite phase to torque pulsation of an internal combustion engine from an electric motor.

  On the other hand, an apparatus that performs control for adjusting the position of the crank angle when the internal combustion engine is stopped is also known. For example, Patent Document 2 discloses a technique of setting a target rotational speed of an electric motor so that a crank angle of an internal combustion engine becomes a target stop position.

Japanese Patent Laid-Open No. 11-082904 JP 2005-016505 A

  However, when the control for suppressing the torque fluctuation as described in Patent Document 1 and the stop position control of the crank angle as described in Patent Document 2 are to be made compatible, an appropriate effect is obtained. May not be obtained. Specifically, for example, when torque is output from an electric motor in order to suppress torque fluctuation of an internal combustion engine, energy applied to the drive shaft of the hybrid vehicle changes, and as a result, the crank angle is stopped at a desired stop position. This causes a technical problem that it becomes difficult.

  The present invention has been made in view of, for example, the above-described problems, and when stopping the internal combustion engine, it is possible to set the crank angle to a desired stop position while suitably suppressing the twist angle fluctuation of the damper. It is an object to provide a control device for a hybrid vehicle.

  In order to solve the above-described problems, a control apparatus for a hybrid vehicle of the present invention includes an internal combustion engine that outputs torque to a power transmission unit via a damper, and an electric motor that outputs torque to the power transmission unit, and further includes the internal combustion engine. A control device for a hybrid vehicle, comprising crank angle control means for executing crank angle control for stopping the crank angle of the internal combustion engine at a predetermined position when the engine is stopped. In order to reduce the torsional angle fluctuation of the damper that occurs, the torque calculation means for calculating the fluctuation suppression torque to be output from the electric motor is compared with the positive and negative absolute values of the fluctuation suppression torque, and the larger one Output control means for controlling the electric motor so as to output the fluctuation suppression torque after aligning the absolute value with the smaller absolute value.

  The hybrid vehicle according to the present invention includes an internal combustion engine and an electric motor as power sources. The internal combustion engine is, for example, a gasoline engine, and is configured to be able to output torque to a power transmission unit via a damper. The electric motor is, for example, a motor / generator, and is configured to be able to output torque to the power transmission unit. The power transmission unit is, for example, a planetary gear mechanism, and is configured to be able to transmit torque from the internal combustion engine and the electric motor to the drive shaft of the hybrid vehicle. The power transmission unit can also transmit torque from the electric motor to the internal combustion engine side.

  The hybrid vehicle according to the present invention further includes crank angle control means for performing crank angle control of the internal combustion engine. The crank angle control is a control for stopping the crank angle of the internal combustion engine at a predetermined position when the internal combustion engine is stopped. Specifically, when the internal combustion engine is requested to stop, the electric motor is controlled by the crank angle control means, and torque for stopping the crank angle of the internal combustion engine at a predetermined position is output. When the electric motor outputs torque for reducing the rotational speed of the internal combustion engine, torque for adjusting the crank angle is output in addition to the reduction torque. If the crank angle can be set to a desired stop position, it is possible to effectively reduce vibration that may occur at the next start of the internal combustion engine.

  The hybrid vehicle control device according to the present invention is a control device that controls such a hybrid vehicle, and includes, for example, one or a plurality of CPUs (Central Processing Units), MPUs (Micro Processing Units), various processors, or various controllers. Alternatively, various processing units such as a single or a plurality of ECUs (Electronic Control Units), which may appropriately include various storage means such as a ROM (Read Only Memory), a RAM (Random Access Memory), a buffer memory or a flash memory. Various computer systems such as various controllers or microcomputer devices can be used.

  When stopping the internal combustion engine of the hybrid vehicle, fluctuations in the torsion angle of the damper may occur due to torque pulsation of the internal combustion engine. For this reason, in the hybrid vehicle control apparatus according to the present invention, in order to reduce the torsional angle fluctuation of the damper that occurs when the internal combustion engine is stopped (in other words, when the crank angle control described above is performed), the fluctuation is further changed from the electric motor. Output suppression torque.

  The fluctuation suppression torque is calculated by a torque calculation unit. The torque calculation means calculates, for example, a torque whose phase is shifted by 180 degrees with respect to the torque pulsation of the internal combustion engine as the fluctuation suppression torque. The fluctuation suppression torque may be any torque that can reduce the fluctuation of the torsion angle of the damper to some extent. In other words, the fluctuation suppressing torque need not be such that fluctuation of the torsion angle of the damper is completely zero.

  The calculated fluctuation suppression torque is not output as it is, but the output control means compares the positive and negative absolute values with each other. The fluctuation suppression torque is actually output after aligning the larger absolute value of the positive and negative absolute values with the smaller absolute value. Specifically, when the positive absolute value is larger than the negative absolute value, the fluctuation suppression torque is output after the positive absolute value is aligned with the negative absolute value. On the other hand, when the positive absolute value is smaller than the negative absolute value, the fluctuation suppression torque is output after the negative absolute value is aligned with the positive absolute value.

  Here, the fluctuation suppression torque at the stage calculated by the torque calculation means is a value obtained by measuring and mapping the compression torque during the stop control of the internal combustion engine, for example. For this reason, the magnitude of torque at the time of compression and expansion differs due to, for example, air leakage from the valve in the compression stroke or the presence of crank offset, and as a result, the positive and negative integrated values are zero. It will be calculated as a non-value. Therefore, if the calculated fluctuation suppression torque is output as it is, the energy given to the drive shaft changes, and the crank angle may not be brought to a desired stop position by crank angle control.

  However, in this embodiment, in particular, as described above, the fluctuation suppression torque is output after the positive and negative absolute values are aligned. When the positive and negative absolute values of the fluctuation suppression torque are aligned, the positive and negative integrated values of the fluctuation suppression torque become zero (or a value very close to zero). For this reason, even if the fluctuation suppression torque is output, the energy given to the drive shaft of the hybrid vehicle does not change, and the crank angle control can be suitably executed.

  It should be noted that the output fluctuation suppression torque preferably has the same positive and negative absolute values. However, even if the larger absolute value is brought closer to the smaller absolute value, the above-described effects are appropriate. Is obtained. In other words, “alignment” here is a broad concept that includes not only the meaning of aligning so that the values are completely the same, but also the meaning of bringing the larger absolute value closer to the smaller absolute value.

  In addition, the absolute value of the fluctuation suppression torque according to the present invention can be rephrased as an integrated value of the fluctuation suppression torque. That is, the positive torque integrated value and the negative torque integrated value are aligned with each other, so that the above-described effect is exhibited.

  Incidentally, the fluctuation suppressing torque has a cycle in which positive torque and negative torque are alternately output. Here, from the viewpoint of bringing the accumulated energy of the fluctuation suppression torque close to zero, a situation in which the stop control of the internal combustion engine ends before the fluctuation suppression torque is output for one cycle (for example, only positive torque is output). Thus, it is preferable to avoid a situation where the process ends without outputting a negative torque. For this reason, when the stop timing of the internal combustion engine can be predicted from the rotational speed of the internal combustion engine, the output of the fluctuation suppression torque is finished before the final cycle (that is, the cycle in which one of the positive and negative torque is applied). You may make it.

  As described above, according to the control apparatus for a hybrid vehicle according to the present invention, when the internal combustion engine is stopped, the crank angle can be set to a desired stop position while suitably suppressing the twist angle fluctuation of the damper. Is possible.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

It is a schematic structure figure showing the whole hybrid vehicle composition concerning an embodiment. It is a conceptual diagram which shows the control content of the control apparatus of the hybrid vehicle which concerns on embodiment. It is a conceptual diagram which shows the fluctuation | variation of each stroke and engine torque in a 4-cylinder internal combustion engine. It is a flowchart which shows the flow of operation | movement of the control apparatus of the hybrid vehicle which concerns on embodiment. It is a graph which shows an example of the fluctuation suppression torque at the time of calculation. It is a time chart which shows the fluctuation | variation of MG1 torque and crank angle in the engine stop control which concerns on a comparative example. It is a graph which shows an example of the fluctuation suppression torque after adjustment. It is a time chart which shows the fluctuation | variation of MG1 torque and crank angle in the engine stop control which concerns on embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

<Configuration of hybrid vehicle>
First, a configuration of a hybrid vehicle to which the hybrid vehicle control device according to the present embodiment is applied will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing the overall configuration of the hybrid vehicle according to the present embodiment.

  In FIG. 1, the hybrid vehicle 1 according to the present embodiment includes an engine 3, a first motor / generator 4, and a second motor / generator 5 as power sources.

  The engine 3 is an example of an “internal combustion engine” according to the present invention, and is configured as an in-line two-cylinder spark ignition engine including two cylinders 2. Since the engine 3 is a two-cylinder four-stroke one-cycle engine, the ignition interval of each cylinder 2 is set to 360 degrees as a crank angle.

  The first motor / generator 4 includes a stator 4a and a rotor 4b. The stator 4a is fixed to the case 10. The first motor / generator 4 functions as a generator that generates power by receiving the power of the engine 3 divided by the power split mechanism 6 and also functions as an electric motor driven by AC power. Similarly, the second motor / generator 5 includes a stator 5a and a rotor 5b fixed to the case 10, and functions as an electric motor and a generator, respectively. The first motor / generator 4 is an example of the “motor” according to the present invention.

  The engine 3, the first motor / generator 4 and the second motor / generator 5 are connected to a power split mechanism 6 provided in the transmission path Tp. The power split mechanism 6 is an example of a “power transmission unit” according to the present invention, and is configured as a single pinion type planetary gear mechanism. The power split mechanism 6 is a planet that holds a sun gear S as an external gear, a ring gear R as an internal gear arranged coaxially with the sun gear S, and a pinion P meshing with these gears S and R so as to be able to rotate and revolve. Carrier C. The engine torque output by the engine 3 is transmitted via the torsional damper 17 to the planet carrier C of the power split mechanism 6 provided in the transmission path Tp.

  The rotor 4 b of the first motor / generator 4 is connected to the sun gear S of the power split mechanism 6. Torque output from the power split mechanism 6 via the ring gear R is transmitted to the output gear 20. Torque output from the output gear 20 is transmitted to drive wheels (not shown) via various transmission mechanisms.

  Control of each part of the hybrid vehicle 1 is controlled by an electronic control unit (ECU) 30, which is an example of a “hybrid vehicle control device”. The ECU 30 performs various controls on the engine 3 and the motor / generators 4 and 5.

  Various information on the hybrid vehicle 1 is input to the ECU 30. For example, the ECU 30 outputs an output signal of the first resolver 31 that outputs a signal according to the rotation angle of the first motor / generator 4 and a second resolver that outputs a signal according to the rotation angle of the second motor / generator 5. 32, an output signal of an accelerator opening sensor 33 that outputs a signal corresponding to the amount of depression of the accelerator pedal 34, an output signal of a vehicle speed sensor 35 that outputs a signal corresponding to the vehicle speed of the hybrid vehicle 1, and an engine And an output signal of a crank angle sensor 36 that outputs a signal corresponding to a crank angle of 3 is input.

  The ECU 30 calculates the required driving force requested by the driver with reference to the output signal of the accelerator opening sensor 33 and the output signal of the vehicle speed sensor 35, and performs various operations so that the system efficiency for the required driving force is optimized. The hybrid vehicle 1 is controlled while switching modes. For example, in the low load region where the thermal efficiency of the engine 3 is reduced, the EV mode in which the combustion of the engine 3 is stopped and the second motor / generator 5 is driven is selected. When the torque is insufficient with only the engine 3, the hybrid mode is selected in which the engine 3 and the second motor / generator 5 are used as a driving source for traveling.

<Variation suppression torque output control>
Next, with reference to FIG.2 and FIG.3, the basic matter of the fluctuation suppression torque output control which the hybrid vehicle control apparatus which concerns on this embodiment performs is demonstrated. FIG. 2 is a conceptual diagram showing the control contents of the hybrid vehicle control device according to this embodiment. FIG. 3 is a conceptual diagram showing variations in each stroke and engine torque in a four-cylinder engine.

  FIG. 2 shows the stroke of each cylinder 2 of the engine 3, the input torque input from the engine 3 to the torsional damper 17, the input torque input from the first motor / generator 4 to the torsional damper 17, and these inputs. A change corresponding to the crank angle of the combined torque obtained by combining the torque is shown in one cycle. 2 and 3 are schematic torque waveforms in which fine torque fluctuations of actual machines, torque variations of each cylinder, and the like are omitted.

  As shown in FIG. 2, the stroke of each cylinder 2 of the engine 3 is as shown, and the ignition interval between the # 1 and # 2 cylinders is 360 degrees in crank angle. The input torque input from the engine 3 to the torsional damper 17 changes as shown in the figure, and has a positive peak in the expansion stroke of each cylinder 2 and a negative peak in the compression stroke of each cylinder 2. A discontinuous torque waveform Te in which the input between the peaks is 0 is obtained. This waveform Te corresponds to the torque pulsation of the engine torque output from the engine 3.

  On the other hand, in the present embodiment, the motor torque having the same period that is 180 degrees out of phase with the torque pulsation of the engine torque is output from the first motor / generator 4 as the fluctuation suppression torque. Therefore, the input torque input to the torsional damper 17 from the first motor / generator 4 has a waveform Tm that is 180 degrees out of phase with the waveform Te as shown in the figure.

  A waveform Tc obtained by synthesizing these waveforms Te and Tm is continuous, and the frequency of the torque input to the torsional damper 17 increases as compared with the case where only the engine torque of the engine 3 is input. That is, it appears to be equivalent to the torque waveform of the engine torque of the 4-cylinder engine shown in FIG.

  In the case of the present embodiment, the frequency of the engine torque passes through the resonance point of the torsional damper 17 at a predetermined engine speed in the process of stopping the engine 3, but the torsional torque is controlled by performing the fluctuation suppression torque output control shown in FIG. The resonance point of the torsional damper 17 can be avoided by increasing the frequency of the input torque input to the damper 17. Therefore, resonance of the torsional damper 17 can be avoided in the process in which the engine 3 is stopped.

<Description of processing>
Below, with reference to FIG. 4, the flow of the various processes which the control apparatus of the hybrid vehicle which concerns on this embodiment performs is demonstrated in detail. FIG. 4 is a flowchart showing the flow of operation of the hybrid vehicle control device according to this embodiment.

  In FIG. 4, when the hybrid vehicle control device according to the present embodiment is operating, it is first determined whether or not there is a stop request for the engine 3 (step S101). The engine 3 is requested to be stopped, for example, from the hybrid mode (that is, the mode in which the engine 3 and the first motor / generator 4 and the second motor / generator 5 are driven) to the EV mode (that is, the engine 3 is stopped). This occurs when a predetermined condition is satisfied, such as when switching to a mode in which only the first motor / generator 4 and the second motor / generator 5 are driven to travel.

  If there is no stop request for the engine 3 (step S101: NO), the series of processing ends. On the other hand, when there is a stop request for the engine 3 (step S101: YES), stop control of the engine 3 is started (step S102). Since the stop control of the engine 3 can be executed, for example, as a well-known one with a fuel cut, a detailed description thereof is omitted here.

  When the stop control of the engine 3 is started, the crank angle of the engine 3 is acquired with reference to the crank angle sensor 36 (step S103).

  When the crank angle of the engine 3 is acquired, the fluctuation suppression torque to be output from the first motor / generator 4 is calculated based on the acquired crank angle (step S104). Specifically, the fluctuation suppression torque is calculated using a map in which the crank angle and the motor torque are associated in advance. This map is created on the basis of a survey result obtained by examining the engine torque for each crank angle from the start to the end of the stop control in advance, and is stored in the ECU 30. In this map, as the motor torque to be calculated, the torque obtained by multiplying the engine torque that is 180 degrees out of phase with the engine torque at a certain crank angle and the gear ratio of the power split mechanism 6 corresponds to each crank angle. It is attached.

  The ECU 30 serving as the control device for the hybrid vehicle functions as “torque calculation means” according to the present invention by executing the above steps S103 to S104.

  The torque to be output from the first motor / generator 4 includes, in addition to the fluctuation suppression torque, a rotation reduction torque for reducing the rotational speed of the engine 3 and a crank angle for stopping the crank angle at a desired position. A position control torque is calculated. Here, a detailed description of the calculation method of the rotational speed reduction torque and the crank angle position control torque is omitted.

  In the present embodiment, the calculated fluctuation suppression torque is not output as it is, but is output after adjustment processing. Below, with reference to FIG.5 and FIG.6, the reason which should perform adjustment of a fluctuation suppression torque is demonstrated concretely. FIG. 5 is a graph showing an example of fluctuation suppression torque at the time of calculation. FIG. 6 is a time chart showing fluctuations in MG1 torque and crank angle in engine stop control according to the comparative example.

  As shown in FIG. 5, the calculated fluctuation suppression torque may not have the same positive torque integrated value and negative torque integrated value. This is due to the fact that the magnitude of torque during compression and expansion varies depending on, for example, air leakage from the valve during the compression stroke or crank offset.

  As shown in FIG. 6, when the rotation speed reduction torque and the crank angle position control torque excluding the fluctuation suppression torque are output from the first motor / generator 4, the crank angle after the engine 2 is stopped becomes the target angle (in the figure). (See dashed line). In this way, if the crank angle can be stopped at a target angle near top dead center, it is possible to effectively reduce vibrations that occur when the engine 2 is started next time.

  On the other hand, when the fluctuation suppression torque is output from the first motor / generator 4 in addition to the rotation speed reduction torque and the crank angle position control torque, it is difficult to accurately control the stop position of the crank angle ( (See the solid line in the figure). This is because the integrated value of the positive torque and the integrated value of the negative torque of the fluctuation suppression torque are different (that is, the integrated energy is not zero). As for the fluctuation suppression torque output immediately before the engine 2 is stopped, only the positive torque is output and the negative torque is not output because of the timing of ending the torque output control. As a result, the difference between the integrated value of the positive torque and the integrated value of the negative torque in the fluctuation suppression torque is greatly widened.

  In order to solve the above-described problem, the control apparatus for a hybrid vehicle according to the present embodiment performs an adjustment process to be described later on the calculated fluctuation suppression torque.

  Returning to FIG. 4, when the motor torque is calculated, the integrated value of the positive torque and the integrated value of the negative torque of the fluctuation suppressing torque are compared (step S <b> 105). That is, the magnitude relationship between the positive torque and the negative torque is determined. Then, the fluctuation suppression torque is adjusted so that the torque having the larger integrated value of the positive torque and the negative torque is aligned with the torque having the smaller integrated value (step S106). After the fluctuation suppression torque is adjusted, the first motor / generator 4 is controlled so as to output the rotation reduction torque and the crank angle position control torque in addition to the fluctuation suppression torque (step S107).

  The ECU 30 serving as the control device for the hybrid vehicle functions as “output control means” and “crank angle control means” according to the present invention by executing the above steps S105 to S107.

  After the output of torque from the first motor / generator 4 is started, it is determined whether or not the rotational speed of the engine 2 is equal to or less than a predetermined value (step S108). Here, the “predetermined value” is a threshold value for determining that the timing for ending the output of torque from the first motor / generator 4 is approaching, and is obtained and stored in advance through experiments or the like. Yes.

  Here, when it determines with the rotation speed of the engine 2 not being below a predetermined value (step S108: NO), the process after step S103 is repeated. That is, torque including fluctuation suppression torque is continuously output from the first motor / generator 4. On the other hand, when it is determined that the rotational speed of the engine 2 is equal to or lower than the predetermined value (step S108: YES), torque output from the first motor / generator 4 is ended (step S109).

  Note that the above-described termination of torque output is performed in order to prevent the occurrence of a rattling sound due to the fluctuation suppression torque straddling positive and negative when, for example, the rotational speed of the engine 2 becomes low. However, in this embodiment, if the torque output is terminated only considering the suppression of the above-described rattling noise, the torque output is terminated in a state where only a positive torque is output as shown in FIG. A situation can occur. For this reason, the “predetermined value” according to the present embodiment is set as a value that can prevent the fluctuation suppression torque from being partially output. Specifically, the “predetermined value” according to the present embodiment is set as a larger value than usual, and as a result, the output of torque is terminated early.

  Finally, with reference to FIG. 7 and FIG. 8, the adjustment method of the fluctuation suppression torque and the effect thereof will be described in detail. FIG. 7 is a graph showing an example of the fluctuation suppression torque after adjustment. FIG. 8 is a time chart showing fluctuations in MG1 torque and crank angle in the engine stop control according to the present embodiment.

  As shown in FIG. 7, in the fluctuation suppression torque at the time of calculation (see FIG. 5), the integrated value of the negative torque is larger than the integrated value of the positive torque. It is aligned with the integrated value. Accordingly, the positive torque integrated value and the negative torque integrated value of the fluctuation suppressing torque are the same value, and the integrated energy of the fluctuation suppressing torque is zero.

  As shown in FIG. 8, according to the adjusted fluctuation suppressing torque, since the accumulated energy is zero, the crank angle stop position control is not adversely affected as described with reference to FIG. For this reason, it is possible to set the crank angle to a desired stop position while suppressing the fluctuation of the torsional angle of the torsional damper 17 by the fluctuation suppressing torque.

  Further, in the present embodiment, the output of torque from the first motor / generator 4 is terminated at an appropriate timing by the processing of steps S108 to S109 described above. For this reason, the fluctuation suppression torque is prevented from being partially output, and the crank angle stop position can be controlled more accurately.

  As described above, according to the control apparatus for a hybrid vehicle according to the present embodiment, the crank angle is set to a desired stop position while suppressing the fluctuation of the twist angle of the torsional damper 17 during the stop control of the engine 3. It is possible.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and control of a hybrid vehicle involving such a change. The apparatus is also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Hybrid vehicle 2 Cylinder 3 Engine 4 1st motor generator 5 Second motor generator 6 Power split mechanism 17 Torsional damper 20 Output gear 30 ECU
31 First resolver 32 Second resolver 33 Accelerator opening sensor 34 Accelerator pedal 35 Vehicle speed sensor 36 Crank angle sensor Tp Transmission path

Claims (1)

An internal combustion engine that outputs torque to a power transmission unit via a damper, and an electric motor that outputs torque to the power transmission unit, and when the internal combustion engine is stopped, the crank angle of the internal combustion engine is stopped at a predetermined position. A control device for a hybrid vehicle, comprising crank angle control means for executing crank angle control for causing
Torque calculation means for calculating a fluctuation suppression torque to be output from the electric motor in order to reduce the torsional angle fluctuation of the damper that occurs during execution of the crank angle control;
Output control means for comparing the positive and negative absolute values of the fluctuation suppression torque and controlling the electric motor so as to output the fluctuation suppression torque after aligning the larger absolute value with the smaller absolute value. A control apparatus for a hybrid vehicle, comprising:

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