JP2020111174A - Control device of power train - Google Patents

Abstract

To properly generate the reaction force of an internal combustion engine on at least one of a case that regenerative torque is exerted on a first motor generator together with a second motor generator during vehicle speed reduction, and a case that driving torque is exerted on the first motor generator together with the second motor generator during vehicle acceleration.SOLUTION: A control device calculates the regenerative reaction force of an internal combustion engine necessary for exerting regenerative torque to an MG2 and an MG1, when performing both regenerative control during vehicle speed reduction, and executes speed reduction piston position correcting processing for controlling a piston stop position so as to be a piston stop position at regeneration which satisfies reaction force at regeneration. The control device calculates reaction force at driving of the internal combustion engine necessary for exerting driving torque on the MG2 together with MG2 when performing both driving control during vehicle acceleration, and executes an acceleration piston position correcting processing for controlling the piston stop position so as to be a piston stop position at driving which satisfies reaction force at driving.SELECTED DRAWING: Figure 4

Description

The present invention relates to a power train control device, and more particularly to a power train control device for a hybrid vehicle including an internal combustion engine and an electric motor as power sources.

For example, Patent Document 1 discloses a hybrid vehicle including an internal combustion engine, first and second motor generators, and a power split mechanism as a power source. This power split mechanism has three rotary elements that are respectively coupled to the rotary shaft of the internal combustion engine, the rotary shaft of the first motor generator, and the rotary shaft of the second motor generator. Further, the internal combustion engine includes a variable valve mechanism that can change the opening/closing timing while maintaining the opening period of the intake valve.

In addition, in the hybrid vehicle, the variable valve mechanism is controlled in order to increase the amount of energy recovered by regenerative braking by using the first motor generator together with the second motor generator when the vehicle is decelerated with the operation of the internal combustion engine stopped. .. Specifically, the opening/closing timing of the intake valve is advanced to increase the engine reaction force during the compression stroke by increasing the amount of air compressed in the cylinder.

JP, 2016-130082, A

According to the method described in Patent Document 1, the reaction force of the internal combustion engine required to increase the amount of energy recovered by regenerative braking by using the first motor generator together with the second motor generator during vehicle deceleration, depending on the operating conditions of the vehicle. It is considered that there may be a shortage.

The present invention has been made in view of the problems as described above, and in the case of causing the first motor generator to generate regenerative torque together with the second motor generator during vehicle deceleration, and the first motor generator together with the second motor generator during vehicle acceleration. An object of the present invention is to provide a power train control device that can appropriately generate a reaction force of an internal combustion engine in at least one of a case where a motor generator exerts a driving torque.

A control device for a power train according to the present invention includes an internal combustion engine, a first motor generator, a second motor generator, and a power split mechanism. The power split mechanism has three rotary elements that are respectively coupled to the rotary shaft of the internal combustion engine, the rotary shaft of the first motor generator, and the rotary shaft of the second motor generator. The rotating element connected to the rotating shaft of the generator is connected to driving wheels of the vehicle.
The control device includes a regenerative control that causes the first motor generator together with the second motor generator to generate a regenerative torque when the vehicle is decelerated due to the operation stop of the internal combustion engine, and a vehicle acceleration accompanied by the operation stop of the internal combustion engine. At least one of both drive controls that causes the first motor generator to generate a drive torque together with the second motor generator is executed.
When performing the regenerative control, the control device calculates a regenerative reaction force of the internal combustion engine required to cause the first motor generator together with the second motor generator to exert a regenerative torque, and regenerates the regenerative power. A regeneration piston stop position that satisfies the time reaction force is calculated, and deceleration piston position correction processing is executed to control the piston stop position of the internal combustion engine so that the regeneration piston stop position is reached.
When performing the both drive control, the control device calculates a driving reaction force of the internal combustion engine required to cause the first motor generator together with the second motor generator to generate a driving torque, and drives the driving. A driving piston stop position that satisfies the time reaction force is calculated, and acceleration piston position correction processing is executed to control the piston stop position of the internal combustion engine so that the driving piston stop position is reached.

According to the regenerative control during vehicle deceleration according to the present invention, the regenerative reaction force of the internal combustion engine required to cause the first motor generator together with the second motor generator to generate regenerative torque is calculated, and The piston stop position is controlled toward the piston stop position during regeneration that can generate a reaction force. This makes it possible to properly secure the required regenerative reaction force. Similarly, the both-drive control during vehicle acceleration according to the present invention also calculates the driving reaction force of the internal combustion engine necessary for causing the first motor generator to exert the driving torque together with the second motor generator, and The piston stop position is controlled toward the drive piston stop position capable of generating the drive reaction force. This makes it possible to properly secure the required reaction force during driving.

It is a figure for explaining a system configuration example of a vehicle to which a control device for a power train according to an embodiment of the present invention is applied. 9 is a graph for explaining an example of operating states of MG1 and MG2 when performing deceleration both regeneration. 9 is a graph for explaining an example of operating states of MG1 and MG2 when only MG2 generates regenerative torque during regenerative braking. 5 is a flowchart showing a routine relating to a process executed by the control device in the embodiment of the present invention. It is a figure for demonstrating the force which acts on a crankshaft at the time of implementation of deceleration both regeneration. It is a figure for demonstrating an example of the calculation method of the torque reaction force (tau) _c at the time of implementation of deceleration both regeneration. It is a figure for demonstrating the force which acts on a crankshaft at the time of implementation of both acceleration drives. It is a figure for explaining an example of a calculation method of torque reaction force τ _e at the time of carrying out both acceleration drive. 6 is a graph showing a relationship between in-cylinder pressure P and elapsed time after engine stop. 6 is a graph showing the relationship between engine friction τ _f and engine temperature.

Embodiments of the present invention will be described below with reference to the accompanying drawings. However, common elements in each drawing are denoted by the same reference numerals, and overlapping description will be omitted or simplified. In the following embodiments, when the number of each element, the number, the quantity, the range, or the like is referred to, the number referred to unless otherwise specified or the principle is clearly specified. However, the present invention is not limited to this. Further, the structures, steps, and the like described in the following embodiments are not necessarily essential to the present invention, unless otherwise specified or clearly specified in principle.

1. System Configuration Example of Vehicle FIG. 1 is a diagram for explaining a system configuration example of a vehicle 1 to which the control device 28 of the power train 10 according to the embodiment of the present invention is applied. The power train 10 shown in FIG. 1 is mounted on the vehicle 1. More specifically, vehicle 1 is a hybrid vehicle including internal combustion engine 12, first motor generator 14 (MG1) and second motor generator 16 (MG2) as its power source. The vehicle 1 further includes a power split mechanism 18, a speed reduction mechanism 20, drive wheels 22, a battery 24, a PCU (Power Control Unit) 26, and a control device 28.

The internal combustion engine 12 is, for example, an in-line four-cylinder engine, and has a piston/crank mechanism 30 (see FIGS. 6 and 8 described later). The internal combustion engine 12 also includes a crank angle sensor 32 that detects a crank angle. MG1 and MG2 are, for example, three-phase AC synchronous motor generators, MG1 is mainly used as a generator, and MG2 is mainly used as an electric motor.

The power split mechanism 18 is configured to split the torque (engine torque) output from the internal combustion engine 12 into the MG 1 and the drive wheels 22. The power split mechanism 18 is composed of, for example, a planetary gear mechanism. More specifically, the sun gear of the planetary gear mechanism is connected to the rotary shaft 34 of MG1, the carrier is connected to the rotary shaft (crank shaft 36) of the internal combustion engine 12, and the ring gear is connected to the rotary shaft 38 of MG2. Are connected. The engine torque is transmitted to the drive wheels 22 via the reduction mechanism 20. Further, the torque output from MG2 (MG2 torque) is also transmitted to drive wheels 22 via reduction mechanism 20. In this way, the power train 10 can drive the vehicle 1 using the engine torque and the MG2 torque.

MG1 can regenerate electric power with the engine torque supplied from internal combustion engine 12 via power split device 18. PCU 26 is a power conversion device including an inverter for driving MG1 and MG2. The electric power generated by MG1 is converted into a voltage by PCU 26 and temporarily stored in battery 24 or directly supplied to MG2. MG2 generates MG2 torque by using the electric power stored in battery 24 or directly using the electric power generated by MG1. Further, MG2 functions as a generator during vehicle deceleration, recovers kinetic energy of the vehicle, and converts it into electric power. The electric power generated by utilizing the regenerative braking is stored in the battery 24.

The control device 28 controls the power train 10 (the internal combustion engine 12, MG1 and MG2). The control device 28 is an electronic control unit (ECU) having a processor and a memory. The memory stores a program for controlling the power train 10. The processor reads the program from the memory and executes it. The control device 28 takes in sensor signals from various sensors (such as the crank angle sensor 32) for controlling the power train 10. Further, the processor executes various programs using the captured sensor signals to operate various actuators of the power train 10 (internal combustion engine 12 (for example, throttle valve, fuel injection valve and ignition device), MG1 and MG2, etc.). The operation signal for performing is output.

2. Powertrain control (control during vehicle deceleration and vehicle acceleration)
The vehicle 1 may be required to have a braking force that exceeds the braking force of regenerative braking using the MG 2. In such a case, it is conceivable that the insufficient braking force is generated by the hydraulic brake. However, with the hydraulic brake, the kinetic energy of the vehicle is lost as heat generated in the braking device. Therefore, it is possible to increase the amount of energy recovered by regenerative braking by using MG1 in addition to MG2 for regenerative braking. If the amount of energy recovered can be increased, the fuel efficiency of the internal combustion engine 12 will be improved. When a high acceleration is required for the vehicle 1 during EV mode traveling in which the internal combustion engine 12 is stopped and the vehicle 1 is driven by the MG2, the MG1 is used for driving the vehicle 1 in addition to the MG2. If it can be used, the acceleration performance of the vehicle 1 can be improved.

Here, the power split device 18 included in the power train 10 of the present embodiment has three rotating elements that are connected to the respective rotary shafts of the internal combustion engine and MG1 and MG2, and is also connected to the rotary shaft of MG2. 2 is an example of a power split mechanism in which a rotating element that is connected to a drive wheel is used. In the case where this type of power split mechanism is used, in order to properly exert the regenerative torque or the drive torque to MG1 together with MG2, it is necessary to ensure that the reaction force necessary for internal combustion engine 12 to keep itself in a stopped state. It is desired to demonstrate.

In the present embodiment, when the vehicle is decelerated with the engine stopped, the regenerative control that causes MG1 and MG1 to exert regenerative torque is executed. Further, when the vehicle is accelerated with the engine operation stopped, both drive controls that cause MG1 and MG1 to exert a drive torque are executed. Then, in view of the above-mentioned problems, the dual regeneration control and the dual drive control are executed with the following piston position correction processing.

Specifically, the control device 28 performs the following deceleration piston position correction processing when performing the regenerative control. That is, the regenerative reaction force of the internal combustion engine 12 required to cause the MG1 and the MG1 to exert the regenerative torque is calculated. Then, the regenerative piston stop position (crank angle during engine stop) that satisfies this regenerative reaction force is calculated. Then, the piston stop position of the internal combustion engine 12 is controlled so as to reach the piston stop position during regeneration.

Performing regenerative braking by using MG1 together with MG2 during deceleration of the vehicle in the EV traveling mode will be appropriately abbreviated as “deceleration both regeneration” hereinafter. Here, with reference to FIGS. 2 and 3, as a premise of the deceleration piston position correction processing, the control of the MG1 torque during execution of deceleration both regeneration will be described. FIG. 2 shows an example of decelerating regenerative regeneration (that is, an example in which both MG1 and MG2 share regenerative torque), and FIG. 3 shows that only MG2 generates regenerative torque for comparison with FIG. In addition, an example in which the MG1 torque is zero is shown. 2 and 3, the vertical axis represents the regenerative torque (negative torque) of MG1 or MG2, and the horizontal axis represents the rotational speed of MG1 or MG2. 2 and 3, the loss contour lines of MG1 or MG2 are shown. The loss of MG1 and MG2 increases as the torque increases, and also increases as the rotation speed increases. The example shown in FIG. 2 and the example shown in FIG. 3 correspond to an example in which the torque finally applied to the axle (driving wheel 22) and the rotational speed are the same.

The MG1 limit torque in FIG. 2 corresponds to the limit value of the MG1 torque that can hold the engine stopped state when the deceleration both regeneration is performed. When the system efficiency is high (that is, the loss of MG1 is low) in the MG1 torque range that is equal to or lower than the MG1 limit torque as in the example of the plot points in FIG. It is performed while maintaining the engine stopped state in which the torque value can be held. On the other hand, when there is no MG1 torque value having a high system efficiency in the MG1 torque range equal to or lower than the MG1 limit torque, both deceleration regeneration is performed while maintaining the engine stopped state capable of holding the MG1 limit torque.

The control device 28 performs the following acceleration piston position correction processing when performing both drive control. That is, the driving reaction force of the internal combustion engine 12 required to cause the MG1 and the MG1 to exert the driving torque is calculated. Then, the driving piston stop position that satisfies the driving reaction force is calculated. Then, the piston stop position is controlled so as to be the driving piston stop position.

Driving the vehicle 1 using the MG1 together with the MG2 at the time of vehicle acceleration in the EV traveling mode is hereinafter abbreviated as "acceleration both drive" as appropriate. Although illustration is omitted here, the concept of MG1 torque control at the time of execution of both acceleration acceleration drive as a premise of the acceleration piston position correction processing is the same as that at the time of deceleration both regeneration described with reference to FIGS. Is. That is, the drive by MG1 is performed using the MG1 torque value that maximizes the system efficiency within the MG1 torque range that is equal to or less than the MG1 limit torque (positive drive torque in this case) that can maintain the engine stopped state. As a result, fuel consumption can be improved by both acceleration and driving. Further, the limit acceleration force of the vehicle in the EV traveling mode is usually determined by the driving force by MG2. However, by using the acceleration both-driving with the piston position correction process for acceleration of the present embodiment, the system efficiency is deteriorated (compared to the case of the total of MG1 and MG2 when compared with the example using only MG2 for driving). It is possible to improve the power performance of the vehicle 1 while suppressing the loss increase).

FIG. 4 is a flowchart showing a routine relating to processing executed by control device 28 in the embodiment of the present invention. The processing of this routine is repeatedly executed during the system startup of the vehicle 1.

In the routine shown in FIG. 4, the control device 28 first executes the EV mode traveling determination in step S101. Specifically, it is determined whether or not the vehicle 1 is currently running in the EV mode (a mode in which the internal combustion engine 12 is stopped and the MG 2 drives the vehicle 1). As a result, when the vehicle is not traveling in the EV mode, this processing cycle is ended.

On the other hand, if the vehicle is traveling in the EV mode, the process proceeds to step S102. In step S102, the control device 28 executes deceleration/bi-regeneration determination. Specifically, in step S102, it is determined whether or not there is a demand for deceleration of the vehicle 1 and the effect of deceleration and regeneration is recognized. For example, when a braking force that exceeds the braking force by regenerative braking using only MG2 is requested, the deceleration both-regenerative determination is affirmed. In this case, the process proceeds to step S103.

In step S103, the controller 28 executes deceleration piston position correction processing. FIG. 5 is a diagram for explaining the force that acts on the crankshaft 36 when the deceleration and regeneration are performed. In FIG. 5, the direction of the force acting on the crankshaft 36 of the internal combustion engine 12 (in other words, the carrier of the power split mechanism 18) is the forward direction (the same as the normal rotation direction of the internal combustion engine 12) on the right side of the drawing. The left direction is the opposite direction (same as the reverse rotation direction of the internal combustion engine 12). This also applies to FIG. 7 described later.

In the example of the power split device 18 having the configuration described with reference to FIG. 1, when the deceleration both-regeneration is performed (that is, the MG1 and the MG2 generate the regenerative torque), the crankshaft 36 in the stopped state. Is applied with a force from MG1 in the forward direction. On the other hand, in the direction opposite to the forward direction, the torque reaction forces τ _c and τ _e act together with the static friction force (engine friction τ _f ). These torque reaction forces τ _c and τ _e are forces caused by the in-cylinder pressures P _c and P _e . The subscripts "c" and "e" indicate the values of the compression stroke and the expansion stroke, respectively.

In the deceleration piston position correction processing of the present embodiment, the torque reaction forces τ _c and τ _e shown in FIG. 5 are increased to increase the regenerative torque of the MG1 in order to implement both deceleration regeneration. It is to properly secure the balance of the resultant force of. As a result, the engine stopped state can be appropriately maintained.

FIG. 6 is a diagram for explaining an example of a method of calculating the torque reaction force τ _c when the deceleration and regeneration are performed. As shown in FIG. 6, the piston/crank mechanism 30 of the internal combustion engine 12 includes a crankshaft 36, a piston 40, and a connecting rod 42. The torque reaction force τ _c , which is the torque reaction force from the cylinder in which the piston 40 is stopped in the compression stroke (compression stroke stopped cylinder) at the time of performing the deceleration regeneration, can be expressed by the following equation (1). .. Such a torque reaction force τ _c acts so as to resist the force from MG1 that tends to rotate the crankshaft 36 in the forward direction shown in FIG.

In the above formula (1), A is the cross-sectional area of the cylinder, r is the turning radius of the crank (length of the crank arm), and P _c is the in-cylinder pressure of the compression stroke stopped cylinder (in-cylinder pressure when the engine is stopped). Is the crank angle (the tilt angle of the crank arm) with reference to the compression top dead center position, and l is the length of the connecting rod 42. The in-cylinder pressure P _c in the equation (1) can be calculated using the equation of the adiabatic cycle shown in the equation (2), for example. The in-cylinder pressure P _icv and the in-cylinder volume V _icv in the equation (2) are values of the closing timing of the intake valve, and the in-cylinder pressure P _icv depends on the intake pressure detected by, for example, an intake pressure sensor (not shown). Can be obtained as a value, and the in-cylinder volume V _icv is a known value. Further, the cylinder volume V _c (cylinder volume when the engine is stopped) of the compression stroke stopped cylinder can be calculated using, for example, the equation (3). V _f in the equation (3) is a known combustion chamber volume (gap volume at the top dead center). In-cylinder pressure _Pc may be acquired using an in-cylinder pressure sensor in the example provided with an in-cylinder pressure sensor.

Further, an internal combustion engine (for example, the internal combustion engine 12 and the internal combustion engine 12 having a cylinder configuration in which the piston 40 is stopped in the expansion stroke together with the compression stroke stopped cylinder and the intake and exhaust valves are closed (expansion stroke stopped cylinder) is present. In the case of the same in-line four-cylinder engine), the torque reaction force τ _e can be expressed by the following equation (4) like the torque reaction force τ _c . Also such torque reaction tau _e, like the torque reaction tau _c, act to resist forces from MG1 to rotate the crankshaft 36 in the forward direction shown in FIG.

In the above formula (4), P _e is the cylinder pressure in the expansion stroke stopped cylinder (cylinder pressure when the engine is stopped). In the equation (5), _Ve is the in-cylinder volume of the expansion stroke stopped cylinder (in-cylinder volume when the engine is stopped). Further, the crank angle (inclination angle of the crank arm) β in the equation (4) has a relationship as shown in the equation (6) with respect to the crank angle α of the cylinder in which the compression stroke is stopped. X in the equation (6) is the number of cylinders. The in-cylinder pressure P _e may be acquired using the in-cylinder pressure sensor in an example including the in-cylinder pressure sensor.

In step S103, first, the control device 28 calculates the forward force (that is, the force from MG1) that acts on the internal combustion engine 12 (crankshaft 36) when the deceleration regeneration is performed. This forward force can be calculated, for example, according to the method already described with reference to FIG.

Then, the control device 28 controls the torque reaction force (τ _c) required to balance the sum of the static friction force (engine friction τ _f ) and the torque reaction forces τ _c and τ _e with the above “forward force”. And τ _e ) are calculated. This torque reaction force (τ _c +τ _e ) corresponds to the “regeneration reaction force” according to the present invention. Next, the control device 28 calculates the value of the crank angle α that satisfies this torque reaction force (τ _c +τ _e ). The value of the crank angle α (piston stop position) corresponds to the “regenerative piston stop position” according to the present invention.

The control device 28 rotationally drives the crankshaft 36 by using MG1 and MG2 so that the crank angle (piston stop position) during the current engine stop becomes the piston stop position during regeneration (that is, piston stop). Control the position).

On the other hand, if the deceleration/bi-regenerative determination is denied in step S102, the process proceeds to step S104. In step S104, the control device 28 performs acceleration/double drive determination. In step S104, it is determined whether or not there is a demand for acceleration of the vehicle 1 and the effect of both acceleration driving is recognized. Specifically, for example, when the degree of acceleration request from the driver is higher than a predetermined level, the acceleration/double drive determination is affirmed. In this case, the process proceeds to step S105. On the other hand, if the acceleration/double drive determination is denied, the current processing cycle is ended.

In step S105, the control device 28 executes acceleration piston position correction processing. FIG. 7 is a diagram for explaining a force that acts on the crankshaft 36 when the acceleration both drive is performed. In the example of the power split device 18 having the configuration described with reference to FIG. 1, when both acceleration driving is performed (that is, when MG1 and MG2 generate driving torque), the crankshaft 36 in the stopped state. , The force from MG1 acts in the opposite direction. On the other hand, in the forward direction, which is the reverse of the reverse direction, the torque reaction forces τ _c and τ _e act together with the static friction force (engine friction τ _f ).

In the acceleration piston position correction process of the present embodiment, the torque reaction forces τ _c and τ _e shown in FIG. 7 are increased to increase the drive torque of the MG1 in order to perform both acceleration drives. It is to properly secure the balance of the resultant force of. As a result, the engine stopped state can be appropriately maintained.

FIG. 8 is a diagram for explaining an example of a method of calculating the torque reaction force τ _e when performing both acceleration drives. Although the torque reaction force τ _e , which is the torque reaction force from the cylinder in which the piston 40 is stopped in the expansion stroke (cylinder in which the expansion stroke is stopped) at the time of performing both acceleration drive, the description of the mathematical expression is omitted here, but the crank angle β Instead of, the crank angle α′ shown in FIG. 8 is used, and can be expressed in the same manner as the equation (4). Such a torque reaction force τ _e acts so as to resist the force from MG1 that attempts to rotate the crankshaft 36 in the opposite direction shown in FIG. Further, also in the example of both the acceleration drive, the torque reaction force τ _c of the compression stroke stopped cylinder can be expressed in the same manner as the expression (1). Such a torque reaction force τ _c also acts in the same manner as the torque reaction force τ _e so as to resist the force from the MG 1 that tends to rotate the crankshaft 36 in the opposite direction shown in FIG. 8.

In step S105, first, the control device 28 calculates the force in the opposite direction (that is, the force from MG1) that acts on the internal combustion engine 12 (crankshaft 36) when the acceleration/double drive is performed. The force in the opposite direction can be calculated, for example, according to the method described above.

Then, the control device 28 controls the torque reaction force (τ _c) necessary to balance the sum of the static friction force (engine friction τ _f ) and the torque reaction forces τ _c and τ _e with the above “reverse direction force”. And τ _e ) is calculated. This torque reaction force (τ _c +τ _e ) corresponds to “driving reaction force” according to the present invention. Next, the control device 28 calculates the value of the crank angle α that satisfies this torque reaction force (τ _c +τ _e ). The value of the crank angle α (piston stop position) corresponds to the “driving piston stop position” according to the present invention.

The control device 28 rotationally drives the crankshaft 36 by using MG1 and MG2 so that the crank angle (piston stop position) at which the engine is currently stopped becomes the piston stop position during driving (that is, piston stop). Control the position).

3. Effect According to the deceleration piston position correction process performed by the control device 28 of the present embodiment described above, when deceleration both regeneration is executed based on a deceleration request while the engine is stopped, internal combustion required for deceleration both regeneration is performed. The piston stop position is controlled toward the regenerative piston stop position (crank angle) capable of generating the regenerative reaction force of the engine 12. This makes it possible to properly secure the required regenerative reaction force. More specifically, it is possible to create a state in which the crankshaft 36 is less likely to rotate in the forward direction. As a result, when MG1 and MG1 generate regenerative torque, it is possible to more easily maintain the engine stop state without using the engine stop mechanism. As a result, the energy loss due to the rotation of the internal combustion engine 12 due to the application of the MG1 torque can be eliminated, so that the effect of both regenerations (that is, the improvement in fuel consumption) can be increased.

Further, according to the acceleration piston position correction process, when the acceleration both-drive is executed based on the acceleration request while the engine is stopped, the internal combustion engine 12 required for the both-acceleration drive is required as in the case of deceleration both-regeneration. The piston stop position is controlled toward the drive piston stop position (crank angle) capable of generating the drive reaction force. This makes it possible to properly secure the required reaction force during driving. More specifically, it is possible to create a state in which the crankshaft 36 is less likely to rotate in the opposite direction. As a result, when MG1 and MG1 generate regenerative torque, it is possible to more easily maintain the engine stop state without using the engine stop mechanism. As a result, the energy loss due to the rotation of the internal combustion engine 12 due to the application of the MG1 torque can be eliminated, and the effect of both drives (that is, the improvement of the vehicle driving force) can be increased.

4. Modifications to Embodiment 4-1. Example in Consideration of In-Cylinder Pressure Leak after Engine Stop FIG. 9 is a graph showing the relationship between in-cylinder pressure P and elapsed time after engine stop. As shown in FIG. 9, the in-cylinder pressure P (P _c , P _e ) after the engine is stopped decreases toward the atmospheric pressure over time. The torque reaction forces τ _c and τ _e described above change according to the in-cylinder pressures P _c and P _e . Therefore, at least one of the deceleration piston position correction process and the acceleration piston position correction process according to the present invention may be performed in consideration of such in-cylinder pressure leakage.

Specifically, for example, is determined in advance as a map the relationship between the elapsed time and the in-cylinder pressure P, as shown in FIG. 9, the torque reaction force tau _c, the cylinder is used to calculate a tau _e internal pressure P _c, is P _e It may be changed according to the elapsed time. Alternatively, instead of such a map, the in-cylinder pressure P acquired according to the elapsed time by using the in-cylinder pressure sensor may be used to calculate the torque reaction forces τ _c and τ _e . As a result, the piston stop position (crank angle) can be controlled while also considering the in-cylinder pressure leakage, so that the engine stopped state can be held more appropriately.

Furthermore, the manner of changing the in-cylinder pressure P according to the elapsed time after the engine is stopped changes according to the engine temperature when the engine is stopped. More specifically, as shown in FIG. 9, the higher the engine temperature when the engine is stopped, the higher the in-cylinder pressure P at each time point after the engine is stopped. Therefore, when a map that defines the relationship between the in-cylinder pressure P and the elapsed time is used, the value of the in-cylinder pressure P in the map indicates the elapsed time as well as the engine temperature (for example, the engine temperature) as shown in the relationship shown in FIG. It may be changed according to the cooling water temperature).

4-2. Example Considering Increase in Engine Friction τ _f After Engine Stop FIG. 10 is a graph showing the relationship between engine friction τ _f and engine temperature. The engine temperature decreases toward the outside air temperature with the lapse of time after the engine is stopped. As shown in FIG. 10, when the engine temperature decreases, the engine friction τ _f increases. When the engine friction τ _f changes, the resultant force balance changes as shown in FIGS. Therefore, at least one of the deceleration piston position correction process and the acceleration piston position correction process according to the present invention may be performed in consideration of such an increase in the engine friction τ _f .

Specifically, for example, the relationship between the engine friction τ _f and the engine temperature (for example, engine cooling water temperature) as shown in FIG. 10 is defined as a map, and the regenerative reaction force is calculated in step S103, and The engine friction τ _f used to calculate the driving reaction force in step S105 may be changed according to the engine temperature after the engine is stopped. As a result, the piston stop position (crank angle) can be controlled in consideration of the increase in engine friction τ _f after the engine is stopped, so that the engine stopped state can be maintained more appropriately.

4-3. Another Example of Execution of Bi-Regenerative Control and Bi-Drive Control In the above-described embodiment, the control device 28 of the power train 10 performs both the bi-regenerative control during vehicle deceleration and the bi-drive control during vehicle acceleration according to the present invention. Is configured to run. Instead of such an example, the control device may be configured to execute only one of the dual regeneration control and the dual drive control.

1 Vehicle 10 Power Train 12 Internal Combustion Engine 14 First Motor Generator (MG1)
16 Second motor generator (MG2)
18 Power split mechanism 20 Reduction mechanism 22 Drive wheel 24 Battery 26 PCU
28 Control Device 30 Piston/Crank Mechanism 32 Crank Angle Sensor 34 Rotation Shaft of MG1 36 Crank Shaft 38 Rotation Shaft of MG2 40 Piston 42 Connecting Rod

Claims (1)

An internal combustion engine,
A first motor generator,
A second motor generator,
The rotary shaft of the internal combustion engine, the rotary shaft of the first motor-generator, and the rotary shaft of the second motor-generator are respectively connected to three rotary elements, and the rotary shaft of the second motor-generator. A power split mechanism in which the rotating element to be coupled is coupled to a drive wheel of a vehicle;
A control device for controlling a power train comprising:
The control device is
A regenerative control that causes the first motor generator together with the second motor generator to generate a regenerative torque when the vehicle is decelerated by stopping the operation of the internal combustion engine, and
At least one of both drive controls that causes the first motor generator to generate a drive torque together with the second motor generator at the time of vehicle acceleration accompanied by stoppage of operation of the internal combustion engine,
The control device, when performing the regenerative control,
Calculating a regenerative reaction force of the internal combustion engine required to cause the first motor generator together with the second motor generator to exert a regenerative torque,
Calculate the regenerative piston stop position that satisfies the regenerative reaction force,
So that the regenerative piston stop position, to perform a deceleration piston position correction process for controlling the piston stop position of the internal combustion engine,
The control device, when performing the both drive control,
Calculating a driving reaction force of the internal combustion engine necessary for causing the first motor generator together with the second motor generator to exert a driving torque,
Calculate the piston stop position during driving that satisfies the reaction force during driving,
A control device for a power train, which executes an accelerating piston position correction process for controlling a piston stop position of the internal combustion engine so that the driving piston stop position is reached.

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