Starting control device for internal combustion engine

Abstract

To provide a starting control device for an internal combustion engine that allows pulsations in torque transmitted from the internal combustion engine to be easily reduced by an electric motor.SOLUTION: A control device for starting an internal combustion engine by outputting torque from an electric motor coupled to a torque transmission path from the internal combustion engine to drive wheels in a manner of being capable of transmitting torque. The control device calculates a pulsation component of reaction torque generated by starting the internal combustion engine, calculates the pulsation component of the torque input to a synthetic position on the basis of the spring constant, a damping coefficient, and a moment of inertia of a power transmission member between the internal combustion engine and the synthetic position where the torque is transmitted from the electric motor to the torque transmission path, and the pulsation component of the reaction torque (Step S4), and determines a torque command value for the electric motor at the time of starting the internal combustion engine by adding an AC component torque corresponding to the pulsation component of the torque input to the synthetic position and cranking torque required for motoring the internal combustion engine (Step S6).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control device that starts an internal combustion engine by motoring it by transmitting torque from an electric motor to the internal combustion engine. [Background technology]

[0002] Patent Document 1 describes a hybrid vehicle in which an engine is connected to a carrier in a single-pinion planetary gear mechanism, a first motor is connected to a sun gear, an intermediate shaft is connected to a ring gear, and a drive wheel is connected to the output side of the intermediate shaft via a speed change mechanism capable of setting a plurality of speed stages including neutral. This hybrid vehicle is configured to be able to set a driving range in which the intermediate shaft and the drive wheel are connected so as to be able to transmit torque by setting a predetermined speed stage by the speed change mechanism, and a non-driving range in which the intermediate shaft and the drive wheel are disconnected by setting the speed change mechanism to a neutral state. Patent Document 1 also describes a start control device configured to switch engine start control based on these driving ranges.

[0003] This start control device is configured to output a cranking torque for motoring the engine from a first motor, and the torque command value of the first motor is configured to be set to a value obtained by adding a damping torque in phase with the pulsation component of the engine torque to the cranking torque for motoring the engine when the driving range is set, and to be set to a value obtained by adding a damping torque in phase opposite to the pulsation component of the engine torque to the cranking torque when the non-driving range is set.

[0004] Patent Document 2 describes a hybrid vehicle in which an engine is connected to a carrier in a single-pinion type planetary gear mechanism, a first motor is connected to a sun gear, drive wheels are connected to a ring gear via a gear train, and a second motor is further connected to the gear train so as to be capable of transmitting torque. This hybrid vehicle also includes a starting control device configured to output cranking torque and vibration damping torque from the first motor to motor the engine, similar to the starting control device described in Patent Document 1. This starting control device is configured to establish an equation of motion for a one-dimensional moment of inertia in the torsional direction of the drive shaft with respect to the resonance of a damper provided between the engine and the carrier, the resonance of the drive shaft, and the resonance of the suspension system of the engine, calculate each resonance frequency in a coupled state based on the equation of motion, calculate an effective torque pulsation map by subtracting the resonance component at each resonance frequency from the torque pulsation map, and calculate the vibration damping torque using the effective torque pulsation map. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-203809 A [Patent Document 2] JP 2019-119405 A Summary of the Invention [Problem to be solved by the invention]

[0006] The starting control device described in Patent Document 1 determines a torque command value for the first motor by adding a damping torque in phase or opposite to a pulsating component of engine torque that is mapped in advance to a cranking torque. However, since the pulsating component of the engine torque fluctuates due to torsion or inertia of members that constitute the power transmission path between the engine and the first motor, even if a damping torque in phase or opposite to the pulsating component is output from the first motor, there is a possibility that the phases will not match at the portion where the torque transmitted from the engine is combined with the torque of the first motor, and sufficient vibration damping cannot be achieved.

[0007] Furthermore, the start control device described in Patent Document 2 is configured to reduce torque pulsation at the time when torque is transmitted from the engine to the drive wheels, and therefore controls the output torque of the first motor and the second motor in a coordinated manner. Therefore, when performing such coordinated control, it is necessary to take into account the control delay of the first motor and the control delay of the second motor, which may make the control complicated.

[0008] The present invention has been made in consideration of the above-mentioned technical problems, and aims to provide an internal combustion engine start control device that can easily reduce torque pulsation transmitted from the internal combustion engine by using an electric motor. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the present invention provides a start control device for an internal combustion engine in which an electric motor is connected to a torque transmission path from the internal combustion engine to a drive wheel so as to be able to transmit torque, and which starts the internal combustion engine by outputting torque from the electric motor, the start control device including a controller for controlling the electric motor, the controller calculating a pulsating component of a reaction torque generated by starting the internal combustion engine, calculating a pulsating component of the torque to be input to the composite position based on at least one parameter of a spring constant, a damping coefficient, and a moment of inertia of a power transmission member between the internal combustion engine and a composite position where torque is transmitted from the electric motor to the torque transmission path, and the pulsating component of the reaction torque, and determining 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 cranking torque required to motor the internal combustion engine.

[0010] In the present invention, the power transmission member may include a damper mechanism that reduces pulsation of the 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.

[0011] In the present invention, the controller may include a map for determining the AC component torque based on a rotation angle of a crankshaft of the internal combustion engine.

[0012] In this invention, the vehicle may include a differential mechanism constituted by a first rotating element to which torque is transmitted from the internal combustion engine, a second rotating element to which torque is transmitted from the electric motor, and a third rotating element connected to the drive wheels so as to be able to transmit torque, and another electric motor connected to a torque transmission path between the third rotating element and the drive wheels. Effect of the Invention

[0013] According to this invention, the pulsation component of the torque input to the composite position is calculated based on at least one of the parameters of the spring constant, damping coefficient, and moment of inertia of the power transmission member between the composite position where the torque is transmitted from the electric motor and the internal combustion engine, and the pulsation component of the reaction torque generated by starting the internal combustion engine, and the torque command value of the electric motor is determined by adding the AC component torque corresponding to the pulsation component of the torque input to the composite position and the cranking torque required to motor the internal combustion engine. By determining the torque command value of the electric motor in this manner, the torque pulsation can be reduced in the process of transmitting the torque from the internal combustion engine to the drive wheels. In addition, the torque command value for reducing the torque pulsation can be determined based on the pulsation of the reaction torque caused by starting the internal combustion engine and the spring constant, damping coefficient, or moment of inertia determined by the structure of the power transmission member that transmits the torque. Therefore, since the pulsation of the torque input to the composite position can be calculated in advance, the torque command value can be determined by feedforward control, and the control can be simplified. [Brief description of the drawings]

[0014] [Figure 1] 1 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. [Diagram 2] FIG. 4 is a diagram showing a change in reaction torque generated during motoring of the engine. [Diagram 3] 3 is a flowchart illustrating an example of control executed by a starting control device according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing an example of a vibration damping map showing the relationship between the torque input from the engine to the carrier and the crank angle. [Diagram 5] 5 is a time chart for illustrating changes in engine speed, crank angle, torque input from the engine to the carrier (input torque), vibration damping gain, and AC component torque of the first motor when the engine is started. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention will be described based on the embodiment shown in the drawings. Note that the embodiment described below is merely one example of a specific embodiment of the present invention, and is not intended to limit the present invention.

[0016] 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 is modeled and shown in Figure 1. The hybrid vehicle (hereinafter referred to simply as a vehicle) Ve shown in Figure 1 includes an engine 1, a first motor 2, and a second motor 3 as driving power sources.

[0017] The engine 1 shown in Fig. 1 can be configured in the same manner as a conventional gasoline engine or diesel engine. That is, it includes a plurality of cylinders (not shown), pistons that reciprocate inside the cylinders, and a connecting rod that transmits the load caused by the reciprocating pistons as torque of the crankshaft 4, which is an output shaft. The engine 1 can be configured as a four-stroke engine that performs an intake stroke in which air is drawn into the cylinders, a compression stroke in which a mixture of air and fuel in the cylinders is compressed, a combustion stroke in which the mixture is combusted, and an exhaust stroke in which exhaust gas generated by the combustion of the mixture is discharged from the cylinders.

[0018] The first motor 2 and the second motor 3 can be configured in the same manner as a motor provided as a driving force source for a conventional hybrid vehicle. That is, in addition to functioning as a motor that outputs driving torque by receiving power from a power storage device (not shown), the motor also functions as a generator that converts at least a part of the motive power into electric power by rotating the output shaft. Specifically, the motor can be configured as a synchronous motor with a permanent magnet in the rotor, an induction motor, or the like.

[0019] A torsional damper 5 for reducing torque pulsation of the engine 1 is connected to the crankshaft 4 of the engine 1. This torsional damper 5 can be configured similarly to a conventional torsional damper, and is configured 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. In FIG. 1, the spring constant of the torsional damper 5 is indicated as "Kdamp" and the damping coefficient of the torsional damper 5 is indicated as "Cdamp". This torsional damper 5 corresponds to the "damper mechanism" in this embodiment of the present invention.

[0020] A power split mechanism 7 is connected to an output rotating member of the torsional damper 5 via an input shaft 6. In Fig. 1, the moment of inertia of the input shaft 6 is marked as "Iinp." This input shaft 6 corresponds to the "torque transmission shaft" in this embodiment of the present invention.

[0021] The power split mechanism 7 can be configured by a differential mechanism that splits the torque of the engine 1 to the first motor 2 and the driving wheels 8. The power split mechanism 7 shown in FIG. 1 is configured by a single-pinion type planetary gear mechanism, in which the first motor 2 is connected to the sun gear S, the input shaft 6 is connected to the carrier C, and the driving wheels 8 are connected to the ring gear R via a gear train unit 9 described later. That is, when transmitting driving torque from the engine 1 to the driving wheels 8, the carrier C functions as an input element, the sun gear S functions as a reaction element, and the ring gear R functions as an output element. In other words, the power split mechanism 7 combines the torque output from the engine 1 with the torque of the first motor 2, and this power split mechanism 7 corresponds to a "combination position" in the embodiment of the present invention. In addition, the carrier C corresponds to the "first rotating element" in an embodiment of this invention, the sun gear S corresponds to the "second rotating element" in an embodiment of this invention, and the ring gear R corresponds to the "third rotating element" in an embodiment of this invention.

[0022] A parking gear 10 is formed on the outer circumferential surface of the ring gear R. In addition, in Fig. 1, the moment of inertia of the parking gear 10 is indicated as "Ipg", and is indicated on the output side of the ring gear R for convenience.

[0023] In the example shown in Fig. 1, an output shaft 11 is connected to the ring gear R, and a drive gear 12 is connected to the output shaft 11. In Fig. 1, the moment of inertia of the output shaft 11 is indicated as "Iop". A power transmission shaft 13 such as a propeller shaft is disposed in parallel to the output shaft 11 of the power split mechanism 7, and a driven gear 14 that meshes with the drive gear 12 is attached to one end of the power transmission shaft 13. The driven gear 14 is formed with a larger diameter than the drive gear 12, and these gear pairs form a reduction mechanism.

[0024] The drive wheels 8 are connected to the power transmission shaft 13 via a differential gear unit 15 and a pair of drive shafts 16. In FIG. 1, the moment of inertia of the differential gear unit 15 is indicated as "Idiff", the spring constant of the drive shaft 16 is indicated as "Kds", the damping coefficient thereof is indicated as "Cds", the moment of inertia of the tires 8a constituting the drive wheels 8 is indicated as "Itire", the spring constant is indicated as "Ktire", and the damping coefficient is indicated as "Ctire". In addition, the longitudinal acceleration of the vehicle body changes due to a change in the driving force caused by factors such as the pulsation of the torque of the engine 1, and as a result, the occupants feel vibration. Therefore, in the example shown in FIG. 1, for the sake of convenience, the moment of inertia equivalent to the weight of the vehicle body is indicated as "Ibody" on the output side of the drive wheels 8 as a model for calculating the longitudinal acceleration of the vehicle body.

[0025] 1, the torque of the second motor 3 is configured to be combined at the driven gear 14. Specifically, the rotor shaft 3a of the second motor 3 is disposed in parallel to the output shaft 11 and the power transmission shaft 13, and an output gear 17 that meshes with the driven gear 14 is attached to the end of the rotor shaft 3a.

[0026] The vehicle Ve described above is further 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. Like ECUs provided in conventional vehicles, this ECU 18 is mainly composed of a microcomputer, and outputs signals to the engine 1, the first motor 2, and the second motor 3 based on input signals and pre-stored arithmetic expressions, maps, and the like. This ECU 18 corresponds to the "controller" in the embodiment of the present invention.

[0027] ECU 18 receives signals from, for example, an accelerator opening sensor that detects the amount of accelerator pedal operation, a vehicle speed sensor that detects the vehicle speed, a crank angle sensor that detects the crank angle of engine 1, a first resolver that detects the rotation angle of first motor 2, a second resolver that detects the rotation angle of second motor 3, a SOC sensor that detects the remaining charge of the power storage device, and a temperature sensor that detects the temperature of the power storage device and each of motors 2 and 3.

[0028] The vehicle Ve described above can be set to at least two driving modes: an engine driving mode in which the engine 1 is driven, and an EV driving mode in which the engine 1 is stopped and the vehicle runs on the power of the second motor 3. Even when the engine driving mode is set, the vehicle is configured to be able to execute idle stop control that stops the engine 1 when the vehicle is stopped.

[0029] 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 to drive the vehicle, and a reaction torque equivalent to the output torque of the engine 1 is output from the first motor 2. The rotation speed of the first motor 2 is controlled so that the torque and rotation speed of the engine 1 change on a predetermined optimum fuel consumption line so that the engine 1 is driven at a driving point with good fuel efficiency. That is, the power split 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. Note that, when the first motor 2 functions as a generator when the reaction torque is output from the first motor 2, the generated power is appropriately supplied to the second motor 3, so that the vehicle can run by adding the power of the second motor 3 at the driven gear 14.

[0030] In the EV driving mode, power equivalent to the power required for the vehicle Ve is output from the second motor 3. When the vehicle is traveling with power output from the second motor 3 in this way, the ring gear R of the power split mechanism 7 rotates at a rotation speed corresponding to the vehicle speed, the first motor 2 rotates freely, and the engine 1 is stopped. This is because the inertia of the engine 1 is greater than the inertia of the first motor 2.

[0031] The vehicle Ve described above is configured to be able to switch between an EV driving mode and an engine driving mode based on the required driving force, the vehicle speed, or the remaining charge of the power storage device. When starting the engine 1 to switch from the EV driving mode to the engine driving mode, or when starting the engine 1 after the idle stop control ends, the engine 1 is motored (cranked) by the first motor 2. Specifically, the engine speed is increased to a predetermined starting speed by controlling the rotation speed of the first motor 2. The first motor 2 corresponds to the "electric motor" in the embodiment of the present invention.

[0032] When motoring the engine 1, the air in the cylinder is compressed as the piston rises, and a compression reaction force acts on the crankshaft 4. That is, a reaction torque acting in a direction to stop the rotation of the crankshaft 4 varies depending on the rotation angle of the crankshaft 4. In addition to the reaction torque associated with the compression reaction force, a reaction torque based on various resistance forces such as the sliding resistance between the piston and the cylinder bore also acts on the crankshaft 4, and this reaction torque changes depending on the rotation angle of the crankshaft 4. That is, when motoring the engine 1, a reaction torque acts against the torque for motoring, and this reaction torque pulsates as shown in FIG. 2. Note that the horizontal axis in FIG. 2 indicates the crank angle (corresponding to time), and the vertical axis indicates the reaction torque.

[0033] Meanwhile, since a torsional damper 5 and an input shaft 6 are provided between the engine 1 and the carrier C, the amplitude and frequency of the reaction torque of the engine 1 fluctuates according to the spring constant, damping coefficient, and the like, and is input to the carrier C. The output torque of the first motor 2 is divided between the carrier C and the ring gear R, and the magnitude of the divided torque depends on the magnitude of the reaction torque acting on the carrier C. Therefore, when a constant torque is output from the first motor 2, the torque output from the ring gear R pulsates in accordance with the pulsation of the reaction torque input to the carrier C. Therefore, the starting control device in the embodiment of the present invention is configured to suppress the pulsation of the torque output from the ring gear R by pulsating the output torque of the first motor 2 according to the magnitude of the reaction torque input to the carrier C.

[0034] A flow chart for explaining an example of this control is shown in Fig. 3. In the control example shown in Fig. 3, first, it is determined whether or not engine start determination is in progress (step S1). This step S1 can be determined based on a flag indicating that it is a transitional period for starting the engine 1, for example, by switching a flag for engine start determination on when it is determined that the EV driving mode has been switched to the engine driving mode or when the idle stop control has ended, and switching the flag off when the engine 1 has reached full combustion.

[0035] If the result of step S1 is NO because the engine start determination is not in progress, the reaction torque of the first motor 2 determined according to the required driving force is output to the first motor 2 as a torque command value for the first motor 2 (step S2), and this routine ends for the time being. That is, the output torque of the engine 1 is calculated based on the required driving force, and 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 split mechanism 7, and the reaction torque is output from the ECU 18 to the first motor 2 as a torque command value for the first motor 2.

[0036] On the other hand, if the engine start determination is in progress and therefore the answer is YES in step S1, the pulsation 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 pulsation torque of the first motor 2 is referred to as the "AC component torque of the first motor."

[0037] Specifically, first, the crank angle is detected (step S3), and a vibration control map is read (step S4). This vibration control map is constructed in advance by experiments and simulations and stored in the ECU 18. Specifically, first, the relationship between the crank angle and the reaction torque of the engine 1 is obtained by experiments and simulations as shown in FIG. 2, and the torque input to the carrier C is obtained based on the pulsating reaction torque of the engine 1 and parameters such as the spring constant, damping coefficient, and moment of inertia of the power transmission member 19 between the engine 1 and the carrier C, such as the torsional damper 5 and the input shaft 6. Specifically, the torque input to the carrier C is obtained by the equation of motion shown in formula (1). To = Te-Kθ-Cdθ / dt-Id 2 θ / dt 2 …(1)

[0038] In addition, in equation (1), To is the torque input from the engine 1 to the carrier C, Te is the torque of the engine 1, K is the total spring constant of the power transmission member 19, C is the total damping constant of the power transmission member 19, I is the total moment of inertia of the power transmission member 19, and θ is the torsion angle of the power transmission member 19.

[0039] Then, the relationship between the crank angle and the torque input to the carrier C is mapped and stored in the ECU 18. Fig. 4 shows an example of a vibration damping map indicating the relationship between the torque input to the carrier C and the crank angle, with the horizontal axis representing the crank angle and the vertical axis representing the torque transmitted to the carrier C.

[0040] Next, the AC component torque of the first motor 2 is calculated based on the crank angle detected in step S3 and the vibration control map (step 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 carrier C and the torque transmitted from the first motor 2 to the carrier C are equal, that is, so that the pulsation component Tin of the combined torque obtained by combining the torque input to the carrier C and the torque input from the first motor 2 to the power split mechanism 7 becomes zero. That is, the AC component torque of the first motor 2 is calculated based on the formula (2). Tin = Tg - To ... (2) Therefore, a 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. For convenience, the gear ratio of the power split mechanism 7 is set to "1".

[0041] Following step S5, the torque obtained by adding the AC component torque of the first motor 2 to the cranking torque required for motoring the engine 1 is output to the first motor 2 as a torque command value for the first motor 2 (step S6), and this routine is temporarily terminated. Note that in the low rotation speed range of the engine 1, the rotation speed becomes the resonance frequency of the power transmission member 19, so that the AC component torque of the first motor 2 may be multiplied by a predetermined gain (vibration damping gain) that is determined in advance according to the rotation speed of the engine 1.

[0042] 5 shows a time chart for explaining the changes in engine speed, crank angle, torque input from engine 1 to carrier C (input torque), vibration damping gain, and AC component torque of first motor 2 (MG1) at engine start. Note that, in order to facilitate calculation of the AC component torque of first motor 2, the crank angle when the piston is in a specified position is set as the reference (zero), and the crank angle at which the piston is located above the reference position (compression side) is shown as a positive value, and the crank angle at which the piston is located below the reference position (expansion side) is shown as a negative value.

[0043] 5, at time t0, the engine 1 is stopped due to the EV driving mode or the idle stop control being in progress. 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, the vibration damping gain, and the AC component torque of the first motor 2 are maintained at zero.

[0044] At time t1, a switch from the EV driving mode to the engine driving mode or an end of the idle stop control is determined, and starting of the engine 1 is requested. Therefore, at time t2, a torque for cranking the engine 1 is output from the first motor 2. Specifically, a torque obtained by adding up the torque required for cranking the engine 1 (cranking torque) and an AC component torque required for suppressing the pulsation of the reaction torque generated by the rotation of the engine 1 is output from the first motor 2. Therefore, as shown in FIG. 5, the AC component torque of the first motor 2 and the pulsation of the torque input from the engine 1 to the carrier C are in phase.

[0045] In this way, the engine speed gradually increases by outputting torque from the first motor 2. In the example shown in Fig. 5, the AC component torque of the first motor 2 is multiplied by a vibration damping gain corresponding to the engine speed, and the vibration damping gain is set to be maximum before the engine speed passes through a predetermined speed band (resonance band).

[0046] Then, at time t3, the engine speed increases to a predetermined speed, and the speed of the power transmission member 19 exceeds the resonant speed (frequency), thereby ending the vibration damping control by the first motor 2. In other words, the addition of the AC component torque to the torque command value of the first motor 2 is stopped.

[0047] As described above, the pulsation component of the torque input from the engine 1 to the carrier C is calculated based on the spring constant, damping coefficient, and moment of inertia of the power transmission member 19 and the pulsation component of the reaction torque generated by starting the engine 1, and the AC component torque of the first motor 2 is determined in accordance with this pulsation component, thereby making it possible to reduce the pulsation of the torque output from the ring gear R.

[0048] Furthermore, the AC component torque of the first motor 2 can be determined based on the pulsation of the reaction torque caused by starting the engine 1 and the spring constant, damping coefficient, or moment of inertia determined by the structure of the power transmission member 19 that transmits the torque. Therefore, since the pulsation of the torque input to the carrier C can be obtained in advance, the torque command value of the first motor 2 can be determined by feedforward control, simplifying the control.

[0049] Furthermore, when starting the engine 1 while the vehicle is running, a braking torque is transmitted to the drive shaft 16 via the power split mechanism 7, which may result in twisting of the drive shaft 16. However, when a torque for suppressing twisting of the drive shaft 16 is output from the second motor 3, by reducing the pulsation of the torque output from the ring gear R as described above, it is not necessary to take into account the pulsation component of the torque transmitted to the drive shaft 16, and vibration suppression control by the second motor 3 can be simplified.

[0050] The internal combustion engine in the embodiment of the present invention is not limited to one connected to a differential mechanism such as the power split mechanism 7, but may be, for example, an internal combustion engine provided on the input side of a torque transmission path in which an electric motor and a speed change mechanism are connected in series. In that case, the pulsation component of the torque input from the electric motor to the position to which the torque is transmitted can be obtained based on the spring constant, damping coefficient, or moment of inertia of the power transmission member provided between the internal combustion engine and the electric motor. Furthermore, in the case of a configuration in which electric motors are connected in series as described above, the AC component torque of the electric motor can be made to have an opposite phase to the pulsation component of the torque input from the electric motor to the position to which the torque is transmitted, thereby reducing the torque pulsation on the output side of the electric motor.

[0051] In the above-mentioned control example, the vibration damping map is stored in advance in the ECU 18, but the pulsation component of the torque input from the carrier C may be constantly calculated. Furthermore, the power split mechanism 7 may be formed of a double pinion type planetary gear mechanism, or may be formed of a compound planetary gear mechanism in which a plurality of planetary gear mechanisms are appropriately connected by a clutch or the like. [Explanation of symbols]

[0052] 1 Engine 2,3 Motor 4 Crankshaft 5 Torsional Damper 6 Input shaft 7 Power split mechanism 8 Drive wheels 18 Electronic Control Unit (ECU) 19 Power transmission components C Carrier R ring gear S Sun gear Ve Hybrid Vehicle

Claims

1. A start control device for an internal combustion engine, in which an electric motor is connected to a torque transmission path from an internal combustion engine to a drive wheel so as to be capable of transmitting torque, and which starts the internal combustion engine by outputting torque from the electric motor, A controller for controlling the electric motor is provided, The controller: A pulsation component of a reaction torque generated by starting the internal combustion engine is obtained; determining a pulsation component of torque input to a combined position where torque is transmitted from the electric motor to the torque transmission path, based on at least one parameter 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, and based on a pulsation component of the reaction torque; A torque command value of the electric motor when starting the internal combustion engine is determined by adding an AC component torque corresponding to a pulsating component of the torque input to the combined position and a cranking torque required for motoring the internal combustion engine. A start control device for an internal combustion engine.

2. 2. A start control device for an internal combustion engine according to claim 1, The power transmission member includes a damper mechanism that reduces pulsation of the 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. A start control device for an internal combustion engine.

3. 2. A start control device for an internal combustion engine according to claim 1, The controller: A map for determining the AC component torque based on the rotation angle of the crankshaft of the internal combustion engine is provided. A start control device for an internal combustion engine.

4. 2. A start control device for an internal combustion engine according to claim 1, a differential mechanism including a first rotating element to which torque is transmitted from the internal combustion engine, a second rotating element to which torque is transmitted from the electric motor, and a third rotating element connected to the drive wheels in a torque transmitting manner; and another electric motor connected to a torque transmission path between the third rotating element and the drive wheels. A start control device for an internal combustion engine.

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