Starting control device for internal combustion engine

Abstract

Provided is a control device for starting an internal combustion engine by outputting torque from an electric motor connected to a torque transmission path from the internal combustion engine to a drive wheel so as to be able to transmit torque, in which: a pulsation component of a reaction torque generated by starting the internal combustion engine is obtained; the pulsation component of the torque input to a resultant position is obtained on the basis of a spring constant, an attenuation coefficient, and an inertia moment of a power transmission member between the resultant position at which the torque is transmitted from the motor to the torque transmission path and the internal combustion engine, and the pulsation component of the reaction torque. The torque command value of the motor when the internal combustion engine is started is determined by adding the AC component torque to the cranking torque.

Description

Technical Field

[0001] The present invention relates to a control device for starting an internal combustion engine by transmitting torque from an electric motor to the internal combustion engine to drive the internal combustion engine. Background Art

[0002] Japanese Patent Application Laid-Open No. 2016-203809 describes a hybrid electric vehicle. In the hybrid electric vehicle, an engine is connected to a gear carrier in a single pinion type planetary gear mechanism. A first motor is connected to the sun gear. An intermediate shaft is connected to the ring gear. A drive wheel is connected to the output side of the intermediate shaft via a transmission mechanism capable of setting a plurality of shift stages including a neutral gear. The hybrid electric vehicle is configured to be able to set a driving gear and a non-driving gear by setting a predetermined shift stage by the transmission mechanism. In the driving gear, the intermediate shaft and the drive wheel are connected in a manner capable of transmitting torque. In the non-driving gear, the intermediate shaft and the drive wheel are disconnected by the transmission mechanism being in a neutral state. In addition, Japanese Patent Application Laid-Open No. 2016-203809 describes a start control device configured to switch the start control of the engine based on these driving gears.

[0003] The starting control device is configured to output a starting torque for dragging the engine from the first motor. When the driving gear is set, the torque command value of the first motor is set to a value obtained by adding a damping torque in phase with the pulsation component of the engine torque to the starting torque for dragging the engine. In addition, when the non-driving gear is set, the torque command value of the first motor is set to a value obtained by adding a damping torque in phase opposite to the pulsation component of the engine torque to the starting torque.

[0004] A hybrid vehicle is described in Japanese Patent Laid-Open No. 2019-119405. In the hybrid vehicle, an engine is connected to a gear carrier in a single pinion type planetary gear mechanism. A first motor is connected to the sun gear. A drive wheel is connected to the ring gear via a gear train. Moreover, the gear train is connected to a second motor in a manner capable of transmitting torque. The hybrid vehicle is provided with a starting control device. The starting control device is also configured to output a starting torque and a damping torque from a first motor to drag the engine, similarly to the starting control device described in Japanese Patent Laid-Open No. 2016-203809. The starting control device described in Japanese Patent Laid-Open No. 2019-119405 is described below. The starting control device is configured to establish an equation of motion. The equation of motion is an equation of motion for a one-dimensional moment of inertia about the torsional direction of the drive shaft for the resonance of a damper disposed between the engine and the gear carrier, the resonance of a drive shaft, and the resonance of a suspension system of the engine. The starting control device is configured to calculate each resonance frequency in a coupled state based on the equation of motion. The start control device is configured to calculate an execution torque ripple map by subtracting a resonance component at each resonance frequency from the torque ripple map. The start control device is configured to calculate a vibration reduction torque using the execution torque ripple map. Summary of the invention

[0005] In the starting control device described in Japanese Patent Laid-Open No. 2016-203809, the torque command value of the first motor is determined by adding the vibration reduction torque in phase or in phase with the pulsation component of the pre-mapped engine torque to the starting torque. However, the pulsation component of the engine torque varies due to the torsion and inertia of the components constituting the power transmission path between the engine and the first motor. Therefore, even if the vibration reduction torque in phase or in phase with the pulsation component is output from the first motor, the phase of the synthesized portion of the torque of the first motor and the torque transmitted from the engine is inconsistent, and it may not be possible to fully reduce vibration.

[0006] In addition, the starting control device described in Japanese Patent Application Laid-Open No. 2019-119405 is configured to reduce the pulsation of the torque at the time when the torque is transmitted from the engine to the drive wheel, so the output torque of the first motor and the second motor are coordinated and controlled. Therefore, when such coordinated control is performed, the control delay of the first motor and the control delay of the second motor need to be considered, and the control may become complicated.

[0007] The present invention has been made in view of the above technical problems, and an object of the present invention is to provide a start control device for an internal combustion engine that can easily reduce the pulsation of torque transmitted from the internal combustion engine by an electric motor.

[0008] In order to achieve the above-mentioned purpose, the present invention relates to a starting control device for an internal combustion engine, wherein an electric motor is connected to a torque transmission path from the internal combustion engine to a driving wheel in a manner capable of transmitting torque, and the internal combustion engine is started by outputting torque from the electric motor. The starting control device for the internal combustion engine is characterized in that the starting control device for the internal combustion engine includes a controller for controlling the electric motor, the controller calculates a pulsating component of a reaction torque generated by starting the internal combustion engine, the controller calculates a pulsating component of a torque input to a composite position at which torque is transmitted from the electric motor to the torque transmission path based on at least any one parameter among a spring constant, a damping coefficient and a moment of inertia of a power transmission member between the internal combustion engine and the composite position at which torque is transmitted from the electric motor to the torque transmission path, and the pulsating component of the reaction torque, the controller determines a torque command value of the electric motor when starting the internal combustion engine by adding an AC component torque corresponding to the pulsating component of the torque input to the composite position and a starting torque required for dragging the internal combustion engine.

[0009] In the present invention, the power transmission member may include: a damper mechanism for reducing pulsation of torque of the internal combustion engine and outputting the torque; and a torque transmission shaft for transmitting torque from the internal combustion engine to the combined position.

[0010] In the present invention, the controller may include a map for obtaining the AC component torque based on a rotation angle of a crankshaft of the internal combustion engine.

[0011] In the present invention, the starting control device of the internal combustion engine may also include: a differential mechanism, which is composed of a first rotating element that transmits torque from the internal combustion engine, a second rotating element that transmits torque from the electric motor, and a third rotating element connected to the drive wheel in a manner capable of transmitting torque; and other electric motors connected to the torque transmission path between the third rotating element and the drive wheel.

[0012] According to the present invention, the pulsating component of the torque input to the synthesis position is obtained based on at least any one parameter of the spring constant, attenuation coefficient and inertia moment of the power transmission member and the pulsating component of the reaction torque. The power transmission member is arranged between the synthesis position where the torque is transmitted from the motor and the internal combustion engine. The pulsating component of the reaction torque is generated by starting the internal combustion engine. The torque command value of the motor is determined by adding the AC component torque corresponding to the pulsating component of the torque input to the synthesis position and the starting torque required to drag the internal combustion engine. By determining the torque command value of the motor in this way, the pulsation of the torque can be reduced in the process of transmitting the torque from the internal combustion engine to the drive wheel. In addition, the torque command value for reducing the pulsation of the torque can be determined based on the pulsation of the reaction torque associated with starting the internal combustion engine and the spring constant, attenuation coefficient or inertia moment determined by the structure of the power transmission member that transmits the torque. Therefore, since the pulsation of the torque input to the synthesis position can be obtained in advance, the torque command value can be determined by feedforward control, and the control can be simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0014] Figure 1 This is a diagram showing a model of an example of a hybrid vehicle equipped with an internal combustion engine according to an embodiment of the present invention.

[0015] Figure 2 This is a diagram showing changes in reaction torque generated when the engine is cranked.

[0016] Figure 3 This is a flowchart for explaining an example of control executed by the startup control device in the embodiment of the present invention.

[0017] Figure 4 This is a diagram showing an example of a vibration reduction map showing the relationship between the torque input from the engine to the carrier and the crank angle.

[0018] Figure 5 It is a timing chart for explaining changes in the engine speed, crank angle, torque input from the engine to the carrier (input torque), vibration reduction gain, and AC component torque of the first motor when the engine is started. DETAILED DESCRIPTION

[0019] The present invention will be described based on the embodiments shown in the drawings. The embodiments described below are merely examples of the present invention, and do not limit the present invention.

[0020] exist Figure 110 is a diagram showing a model of an example of a hybrid vehicle equipped with an internal combustion engine (hereinafter referred to as an engine) according to an embodiment of the present invention. Figure 1 The hybrid vehicle (hereinafter simply referred to as a vehicle) Ve shown includes an engine 1, a first motor 2, and a second motor 3 as drive power sources.

[0021] Figure 1 The engine 1 shown can be constructed in the same manner as conventional gasoline engines and diesel engines. That is, it is provided with a plurality of cylinders not shown, pistons that reciprocate inside these cylinders, and connecting rods that transmit the load that causes the pistons to reciprocate as the torque of the output shaft, i.e., the crankshaft 4. In addition, the engine 1 can be composed of a four-stroke engine that performs an intake stroke, a compression stroke, a combustion stroke, and an exhaust stroke. In the intake stroke, air is sucked into the cylinder. In the compression stroke, the mixture of air and fuel in the cylinder is compressed. In the combustion stroke, the mixture burns. In the exhaust stroke, the exhaust gas generated by the combustion of the mixture is discharged from the cylinder.

[0022] The first motor 2 and the second motor 3 can be configured in the same manner as the motors provided as the driving force source of the conventional hybrid vehicle. That is, in addition to the function of a motor that outputs a driving torque by supplying electric power from an unillustrated power storage device, they also have the function of a generator that converts at least a part of its power into electric power by rotating the output shaft. Specifically, they can be configured by a synchronous motor or an induction motor having a permanent magnet on the rotor.

[0023] A torsional vibration damper 5 for reducing the pulsation of the torque of the engine 1 is connected to the crankshaft 4 of the engine 1. The torsional vibration damper 5 can be constructed in the same manner as a conventional torsional vibration damper, and is constructed to transmit torque from an input rotating member connected to the crankshaft 4 to an output rotating member via a spring that expands and contracts in the circumferential direction of the input rotating member. Figure 1 In FIG. 1 , the spring constant of the torsional vibration damper 5 is represented by “Kdamp”, and the damping coefficient of the torsional vibration damper 5 is represented by “Cdamp”. The torsional vibration damper 5 corresponds to the “damping mechanism” in the embodiment of the present invention.

[0024] The output rotating member of the torsional vibration damper 5 is connected to a power distribution mechanism 7 via an input shaft 6. Figure 1 In FIG. 1 , the inertia moment of the input shaft 6 is expressed as “Iinp.” The input shaft 6 corresponds to the “torque transmission shaft” in the embodiment of the present invention.

[0025] The power split mechanism 7 may be formed of a differential mechanism that distributes the torque of the engine 1 to the first motor 2 and the drive wheels 8 . Figure 1The power distribution mechanism 7 shown is composed of a single pinion type planetary gear mechanism. In the power distribution mechanism 7, the first motor 2 is connected to the sun gear S, the input shaft 6 is connected to the gear carrier C, and the drive wheel 8 is connected to the ring gear R via the gear train 9 described later. That is, when the driving torque is transmitted from the engine 1 to the drive wheel 8, the gear carrier C is configured to function as an input element, the sun gear S functions as a reaction force element, and the ring gear R functions as an output element. In other words, the torque of the first motor 2 and the torque output from the engine 1 are synthesized by the power distribution mechanism 7, and the power distribution mechanism 7 is equivalent to the "synthesized position" in the embodiment of the present invention. In addition, the gear carrier C is equivalent to the "first rotating element" in the embodiment of the present invention, the sun gear S is equivalent to the "second rotating element" in the embodiment of the present invention, and the ring gear R is equivalent to the "third rotating element" in the embodiment of the present invention.

[0026] A parking gear 10 is formed on the outer peripheral surface of the ring gear R. Figure 1 In the figure, the inertia moment of the parking gear 10 is marked as "Ipg" and is marked on the output side of the ring gear R for convenience.

[0027] exist Figure 1 In the example shown, the output shaft 11 is connected to the ring gear R, and the drive gear 12 is connected to the output shaft 11. Figure 1 In the figure, the inertia moment of the output shaft 11 is recorded as "Iop". In addition, a power transmission shaft 13 such as a transmission shaft is arranged in parallel with the output shaft 11 of the power distribution mechanism 7, and a driven gear 14 meshing with the drive gear 12 is installed at one end of the power transmission shaft 13. In addition, the driven gear 14 is formed to have a larger diameter than the drive gear 12, and a speed reduction mechanism is formed by these gear pairs.

[0028] Furthermore, the power transmission shaft 13 is connected to the drive wheels 8 via the differential gear unit 15 and a pair of drive shafts 16. Figure 1 In the figure, the inertia moment of the differential gear unit 15 is recorded as "Idiff". Figure 1 In the figure, the spring constant of the drive shaft 16 is recorded as "Kds" and the attenuation coefficient thereof is recorded as "Cds". Figure 1 In the figure, the inertia moment of the tire 8a constituting the driving wheel 8 is denoted as "Itire". Figure 1 In the example, the spring constant is recorded as "Ktire" and the damping coefficient is recorded as "Ctire". The driving force changes mainly due to the pulsation of the torque of the engine 1, so that the front and rear acceleration of the vehicle body changes, and as a result, the occupants feel vibration. Figure 1In the example shown, as a model for calculating the longitudinal acceleration of the vehicle body, for convenience, the inertia moment corresponding to the weight of the vehicle body on the output side of the drive wheel 8 is denoted as “Ibody”.

[0029] In addition, Figure 1 In the example shown, the torque of the second motor 3 can be synthesized at the driven gear 14. Specifically, the rotor shaft 3a of the second motor 3 is arranged parallel to the output shaft 11 and the power transmission shaft 13, and the output gear 17 meshing with the driven gear 14 is installed at the end of the rotor shaft 3a.

[0030] The vehicle Ve is also provided with an electronic control unit (hereinafter referred to as ECU) 18 for controlling the engine 1, the first motor 2, and the second motor 3. The ECU 18 is mainly composed of a microcomputer, similar to the ECU provided in the conventional vehicle. The ECU 18 outputs signals to the engine 1, the first motor 2, and the second motor 3 based on input signals and pre-stored calculation formulas, maps, etc. The ECU 18 is equivalent to the "controller" in the embodiment of the present invention.

[0031] A signal is input to ECU18. For example, a signal is input to ECU18 from an accelerator opening sensor that detects the amount of operation of the accelerator pedal. For example, a signal is input to ECU18 from a vehicle speed sensor that detects the vehicle speed. For example, a signal is input to ECU18 from a crank angle sensor that detects the crank angle of the engine 1. For example, a signal is input to ECU18 from a first rotary transformer that detects the rotation angle of the first motor 2. For example, a signal is input to ECU18 from a second rotary transformer that detects the rotation angle of the second motor 3. For example, a signal is input to ECU18 from an SOC sensor that detects the remaining charge of the power storage device. For example, a signal is input to ECU18 from a temperature sensor that detects the temperature of the power storage device and each motor 2, 3.

[0032] The vehicle Ve can be set to at least two driving modes: an engine driving mode for driving the engine 1 and an EV driving mode for stopping the engine 1 and driving with the power of the second motor 3. In addition, even when the engine driving mode is set, an idle stop control for stopping the engine 1 can be executed when the vehicle is parked.

[0033] The engine driving mode is a mode in which a part of the torque output from the engine 1 is transmitted to the drive wheels 8 for driving, and a reaction torque equivalent to the output torque of the engine 1 is output from the first motor 2. In addition, the rotation speed of the first motor 2 is controlled so that the torque and the rotation speed of the engine 1 change on a predetermined optimal fuel consumption line, so that the engine 1 is driven at an operating point with good fuel consumption. That is, the power distribution mechanism 7 functions as a continuously variable transmission that controls the rotation speed of the engine 1 by controlling the rotation speed of the first motor 2. In addition, when the first motor 2 functions as a generator when the reaction torque is output from the first motor 2, by appropriately providing the generated power to the second motor 3, the vehicle can travel by adding the power of the second motor 3 to the driven gear 14.

[0034] In the EV driving mode, the second motor 3 outputs power equivalent to the power required by the vehicle Ve. In addition, when the vehicle is driven by outputting power from the second motor 3, the ring gear R of the power distribution mechanism 7 rotates at a speed corresponding to the vehicle speed, the first motor 2 idles, and the engine 1 stops. This is because the inertia of the engine 1 is greater than the inertia of the first motor 2.

[0035] The vehicle Ve is configured to be switchable between the EV driving mode and the engine driving mode based on the required driving force, the vehicle speed, or the remaining charge of the power storage device. When the engine 1 is started to switch from the EV driving mode to the engine driving mode, or when the engine 1 is started after the idling stop control is terminated, the engine 1 is dragged (started) by the first motor 2. Specifically, the engine speed is increased to a preset starting speed by controlling the speed of the first motor 2. In addition, the first motor 2 is equivalent to the "electric motor" in the embodiment of the present invention.

[0036] When the engine 1 is driven, as the piston rises, the air in the cylinder is compressed, and therefore, its compression reaction force acts on the crankshaft 4. That is, according to the rotation angle of the crankshaft 4, the reaction torque acting in the direction of stopping the rotation of the crankshaft 4 changes. In addition, in addition to the reaction torque accompanying the compression reaction force, the reaction torque based on various resistances such as the sliding resistance between the piston and the cylinder hole also acts on the crankshaft 4, and this reaction torque changes according to the rotation angle of the crankshaft 4. That is, when the engine 1 is driven, the reaction torque acts against the torque used for the driving, and this reaction torque is as follows. Figure 2 In addition, Figure 2 The horizontal axis in the figure uses the crankshaft angle (equivalent to time), and the vertical axis uses the reaction force torque.

[0037] On the other hand, since the torsional vibration damper 5 and the input shaft 6 are provided between the engine 1 and the gear carrier C, the amplitude and frequency of the reaction torque of the engine 1 vary according to their spring constants, attenuation coefficients, etc., and are input to the gear carrier C. In addition, the output torque of the first motor 2 is distributed to the gear carrier C and the ring gear R, and the magnitude of the distributed torque depends on the magnitude of the reaction torque acting on the gear carrier C. Therefore, when a constant torque is output from the first motor 2, the torque output from the ring gear R pulsates as the reaction torque input to the gear carrier C pulsates. Therefore, the starting control device in the embodiment of the present invention is configured to cause the output torque of the first motor 2 to pulsate according to the magnitude of the reaction torque input to the gear carrier C, thereby suppressing the pulsation of the torque output from the ring gear R.

[0038] A flowchart for explaining an example of this control is shown in FIG. Figure 3 .exist Figure 3 In the control example shown, first, it is determined whether the engine start determination is in progress (S1). This S1 can be determined based on a flag indicating that the engine 1 is in a transition period. In S1, for example, at the time point when the switch from the EV driving mode to the engine driving mode is determined, or at the time point when the idle stop control ends, the flag for engine start determination is switched on. In S1, for example, at the time point when the engine 1 reaches complete explosion, the flag is switched off.

[0039] When the judgment in S1 is negative because the engine start judgment is not in progress, the reaction torque of the first motor 2 determined based on the required driving force is output to the first motor 2 as the torque command value of the first motor 2 (S2), and the routine is temporarily terminated. That is, the output torque of the engine 1 is calculated based on the required driving force. The reaction torque of the first motor 2 is calculated by multiplying the output torque of the engine 1 by the gear ratio of the power distribution mechanism 7. The reaction torque is output from the ECU 18 to the first motor 2 as the torque command value of the first motor 2.

[0040] On the contrary, when the determination in S1 is affirmative because the engine start determination is in progress, the pulsating torque of the first motor 2 required to reduce the pulsation of the torque output from the ring gear R is determined. In the following description, the pulsating torque of the first motor 2 is referred to as "AC component torque of the first motor".

[0041] Specifically, first, the crank angle is detected (S3), and the vibration reduction map is read (S4). The vibration reduction map is constructed in advance through experiments and simulations and stored in the ECU 18. Specifically, first, as Figure 2As shown, the relationship between the crankshaft angle and the reaction torque of the engine 1 is obtained through experiments and simulations. Next, based on the reaction torque of the pulsating engine 1 and parameters such as the spring constant, attenuation coefficient or inertia moment of the power transmission component 19, the torque input to the gear carrier C is calculated. The power transmission component 19 is arranged between the engine 1 and the gear carrier C, such as the torsional vibration damper 5 and the input shaft 6. Specifically, the torque input to the gear carrier C is calculated by the motion equation shown in formula (1).

[0042] To=Te-Kθ-Cdθ / dt-Id 2 θ / dt 2 … (1)

[0043] In addition, To in the formula (1) is the torque input from the engine 1 to the gear carrier C. Te in the formula (1) is the torque of the engine 1. K in the formula (1) is the total spring constant of the power transmission component 19. C in the formula (1) is the total attenuation constant of the power transmission component 19. I in the formula (1) is the total inertia moment of the power transmission component 19. θ in the formula (1) is the torsion angle of the power transmission component 19.

[0044] Then, the relationship between the crank angle and the torque input to the carrier C is mapped and stored in the ECU 18. Figure 4 2 shows an example of a vibration reduction map indicating the relationship between the torque input to the carrier C and the crank angle. The crank angle is used as the horizontal axis, and the torque transmitted to the carrier C is used as the vertical axis.

[0045] Next, based on the crankshaft angle detected by S3 and the vibration reduction map, the AC component torque of the first motor 2 is calculated (S5). Specifically, the AC component torque Tg of the first motor 2 is calculated so that the torque input from the engine 1 to the gear carrier C is equal to the torque transmitted from the first motor 2 to the gear carrier C. That is, the AC component torque Tg of the first motor 2 is calculated so that the pulsating component Tin of the composite torque obtained by synthesizing the torque input to the gear carrier C and the torque input from the first motor 2 to the power distribution mechanism 7 becomes zero. That is, the AC component torque of the first motor 2 is calculated based on formula (2).

[0046] Tin=Tg-To … (2)

[0047] Therefore, the torque having the same phase and magnitude as the torque input from the engine 1 to the carrier C is obtained as the AC component torque Tg of the first motor 2. In addition, for convenience, the gear ratio of the power split mechanism 7 is set to "1".

[0048] Then, in step S5, the torque obtained by adding the starting torque required for dragging the engine 1 to the AC component torque of the first motor 2 is output to the first motor 2 as the torque command value of the first motor 2 (S6), and the routine is temporarily terminated. In addition, when the rotation speed of the engine 1 is in the low rotation speed region, it becomes the resonance frequency of the power transmission member 19, so the predetermined gain (vibration reduction gain) predetermined according to the rotation speed of the engine 1 may be multiplied by the AC component torque of the first motor 2.

[0049] Figure 5 There are shown time charts for explaining changes in the engine speed, crank angle, input torque, vibration reduction gain, and AC component torque of the first motor 2 (MG1) at the time of engine startup. Figure 5 The input torque is the torque input from the engine 1 to the gear carrier C. In order to easily calculate the AC component torque of the first motor 2, the crankshaft angle is based on the crankshaft angle when the piston is at a predetermined position (zero). A positive value represents the crankshaft angle when the piston is located above the reference position (compression side), and a negative value represents the crankshaft angle when the piston is located below the reference position (expansion side).

[0050] exist Figure 5 In the example shown, at time t0, the vehicle is in EV driving mode or in idle stop control, and the engine 1 is stopped. Therefore, the engine speed is maintained at zero, the crank angle is maintained at a predetermined angle when the engine is stopped, and the input torque, vibration reduction gain, and AC component torque of the first motor 2 are maintained at zero.

[0051] At time point t1, it is determined that the EV driving mode is switched to the engine driving mode, or it is determined that the idle stop control is terminated, and it is required to start the engine 1. Therefore, at time point t2, the torque for starting the engine 1 is output from the first motor 2. Specifically, the torque obtained by adding the starting torque and the AC component torque is output from the first motor 2. The starting torque is the torque required to start the engine 1. The AC component torque is the torque required to suppress the pulsation of the reaction torque generated by the rotation of the engine 1. Therefore, as Figure 5 As shown, the pulsations of the AC component torque of the first motor 2 and the torque input from the engine 1 to the carrier C are in the same phase.

[0052] By outputting torque from the first motor 2 in this way, the engine speed gradually increases. Figure 5 In the example shown, a vibration reduction gain according to the rotation speed of the engine 1 is multiplied by the AC component torque of the first motor 2. The vibration reduction gain is set to be maximum until the engine rotation speed passes through a predetermined rotation speed band (resonance band).

[0053] Then, at time t3, the engine speed increases to a predetermined speed and the speed of the power transmission member 19 exceeds the resonance speed (frequency), thereby ending the vibration reduction control by the first motor 2. That is, the addition of the AC component torque to the torque command value of the first motor 2 is stopped.

[0054] As described above, the pulsation component of the torque input from the engine 1 to the gear carrier C is obtained based on the spring constant, damping coefficient and inertia moment of the power transmission member 19 and the pulsation component of the reaction torque generated by starting the engine 1. By determining the AC component torque in the first motor 2 based on the pulsation component, the pulsation of the torque output from the ring gear R can be reduced.

[0055] In addition, the AC component torque of the first motor 2 can be determined based on the pulsation of the reaction torque associated with starting the engine 1 and the spring constant, damping coefficient or inertia moment determined by the structure of the power transmission member 19 that transmits the torque. Therefore, since the pulsation of the torque input to the gear carrier C can be obtained in advance, the torque command value of the first motor 2 can be determined by feedforward control, which can simplify the control.

[0056] Furthermore, when the engine 1 is started during driving, the braking torque is transmitted to the drive shaft 16 via the power split mechanism 7, and as a result, a torsion may be generated in the drive shaft 16. However, when the second motor 3 outputs a torque for suppressing the torsion of the drive shaft 16, the vibration reduction control performed by the second motor 3 can be simplified. This is because, by reducing the pulsation of the torque output from the ring gear R as described above, it is not necessary to consider the pulsation component of the torque transmitted to the drive shaft 16.

[0057] In addition, the internal combustion engine in the embodiment of the present invention is not limited to the internal combustion engine connected to the differential mechanism such as the power distribution mechanism 7, and can also be, for example, an internal combustion engine arranged on the input side of the torque transmission path that connects the electric motor and the speed change mechanism in series. In this case, it is sufficient to find the pulsating component of the torque input to the position where the torque is transmitted from the electric motor based on the spring constant, attenuation coefficient or inertia moment of the power transmission member arranged between the internal combustion engine and the electric motor. Moreover, in the case of a structure in which the electric motors are connected in series as described above, the AC component torque in the electric motor is a torque of opposite phase to the pulsating component of the torque input to the position where the torque is transmitted from the electric motor. Thereby, the pulsation of the torque on the output side of the electric motor can be reduced.

[0058] In the above control example, an example in which a vibration reduction map is stored in advance in the ECU 18 is used for explanation, but the pulsation component of the torque input from the carrier C may be always calculated and obtained. Furthermore, the power distribution mechanism 7 may be composed of a double pinion type planetary gear mechanism, or may be composed of a compound planetary gear mechanism formed by appropriately connecting a plurality of planetary gear mechanisms using a clutch or the like.

Claims

1. A starting control device for an internal combustion engine, wherein: An electric motor is connected to a torque transmission path from the internal combustion engine to the drive wheels in a torque-transmittable manner, and the internal combustion engine is started by outputting torque from the electric motor. The internal combustion engine start control device includes a controller for controlling the electric motor. The controller obtains a pulsating component of a reaction torque generated by starting the internal combustion engine. The controller obtains the pulsating component of the torque input to the combined position at which the torque is transmitted from the electric motor to the torque transmission path based on at least any one of a spring constant, a damping coefficient and a moment of inertia of a power transmission member between the internal combustion engine and the combined position at which the torque is transmitted from the electric motor to the torque transmission path, and the pulsating component of the reaction torque, The controller adds an AC component torque corresponding to a pulsating component of the torque input to the combined position and a cranking torque required for cranking the internal combustion engine to determine a torque command value for the electric motor when starting the internal combustion engine.

2. The internal combustion engine starting control device according to claim 1, wherein: The power transmission member includes: a damper mechanism that reduces pulsation of torque of the internal combustion engine and outputs the torque; and a torque transmission shaft that transmits torque from the internal combustion engine to the combined position.

3. The internal combustion engine starting control device according to claim 1, wherein: The controller includes a map for obtaining the AC component torque based on a rotation angle of a crankshaft of the internal combustion engine.

4. The internal combustion engine start control device according to claim 1, wherein: The internal combustion engine starting control device comprises: a differential mechanism including a first rotating element that transmits torque from the internal combustion engine, a second rotating element that transmits torque from the electric motor, and a third rotating element that is connected to the drive wheels in a torque-transmittable manner; and The other electric motor is connected to a torque transmission path between the third rotating element and the drive wheel.

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