Hybrid vehicle drivetrain

Abstract

To provide a hybrid vehicle drive device capable of reducing the costs of overall system.SOLUTION: In a hybrid vehicle drive device, a first motor generator and a first rotary element are coupled, an engine and a second rotary element are coupled, a wheel and a third rotary element are coupled, and a second motor generator and a forth rotary element are coupled. Transmission ratio between a third motor generator and the second rotary element / the third rotary element can be controlled continuously variably. If it is a predetermined engine torque or more, the first motor generator and the second motor generator receive the engine torque. If it is less than the predetermined engine torque and is a predetermined transmission ratio or more, the second motor generator receives the engine torque. If it is less than the predetermined engine torque and is less than a predetermined transmission ratio, the first motor generator receives the engine torque.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a drive system for a hybrid vehicle. [Background technology]

[0002] Patent document 1 discloses a structure in which a hybrid vehicle has a power distribution device consisting of first and second planetary gear mechanisms provided between the engine and the wheels, and a first motor generator and a second motor generator connected to the power distribution device, in which the reaction force against the engine torque is borne by the lower-output of the first motor generator or the second motor generator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4069901 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to have each of the first motor generator and the second motor generator independently handle the maximum engine torque, it is necessary to use a high-output motor generator, which increases the cost of the entire system. Therefore, in such cases, there has been a demand for technology that can reduce the cost of the entire system.

[0005] The present disclosure has been made in view of the above, and has an object to provide a drive device for a hybrid vehicle that can reduce the cost of the entire system. [Means for solving the problem]

[0006] The drive device of a hybrid vehicle according to the present disclosure includes an engine, a first motor generator, a second motor generator, a third motor generator connected to a wheel so as to be able to transmit power, and a power distribution device provided in a power transmission path between the engine and the wheel and having first, second, third, and fourth rotating elements that can differentially rotate relative to each other. The first motor generator is connected to the first rotating element, the engine is connected to the second rotating element, the wheel is connected to the third rotating element, the second motor generator is connected to the fourth rotating element, and in the drive device of a hybrid vehicle capable of continuously controlling the gear ratio between the third motor generator and the second and third rotating elements, when the engine torque is greater than or equal to a predetermined engine torque, the first motor generator and the second motor generator receive the engine torque, when the engine torque is less than the predetermined engine torque and the gear ratio is greater than or equal to a predetermined gear ratio, the second motor generator receives the engine torque, and when the engine torque is less than the predetermined engine torque and the gear ratio is less than the predetermined gear ratio, the first motor generator receives the engine torque.

Advantages of the Invention

[0007] According to the present disclosure, the cost of the entire system can be reduced.

Brief Description of the Drawings

[0008] [Figure 1] FIG. 1 is a skeleton diagram schematically showing the configuration of a hybrid vehicle including a drive device according to an embodiment. [Figure 2] FIG. 2 is a collinear diagram at low vehicle speed (Ng1≧Ng2) and high Te (high engine torque) in the drive device of a hybrid vehicle according to an embodiment. [Figure 3] FIG. 3 is a collinear diagram at high vehicle speed (Ng1<Ng2) and high Te (high engine torque) in the drive device of a hybrid vehicle according to an embodiment. [Figure 4]FIG. 4 is a collinear diagram of the drive device of a hybrid vehicle according to an embodiment at low vehicle speed (Ng1≧Ng2) and low Te (low engine torque). [Figure 5] FIG. 5 is a collinear diagram of the drive device of a hybrid vehicle according to an embodiment at high vehicle speed (Ng1<Ng2) and low Te (low engine torque). [Figure 6] FIG. 6 is a graph showing Tg (motor generator torque) with respect to Te (engine torque) at low vehicle speed (Ng1≧Ng2) in the drive device of a hybrid vehicle according to an embodiment. [Figure 7] FIG. 7 is a graph showing Tg (motor generator torque) with respect to Te (engine torque) at high vehicle speed (Ng1<Ng2) in the drive device of a hybrid vehicle according to an embodiment. [Figure 8] FIG. 8 is a flowchart showing the operation of the drive device of a hybrid vehicle according to an embodiment.

Embodiments for Carrying Out the Invention

[0009] The drive device of a hybrid vehicle according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the components in the following embodiments include those that can be replaced by those skilled in the art and are easy to replace, or those that are substantially the same.

[0010] (Device Configuration) FIG. 1 is a skeleton diagram schematically showing the configuration of a hybrid vehicle 1 equipped with a drive device according to an embodiment of the present invention. As shown in the figure, the hybrid vehicle 1 includes an engine 10, an output shaft 11, a power distribution mechanism 20, a first motor generator (MG1) 30, a second motor generator (MG2) 40, a rotating shaft (MG2 shaft) 41, a counter driven gear 42, a counter shaft 43, a counter drive gear 44, a differential 45, an axle 46 to which wheels are connected, a third motor generator (MG3) 50, and a rotating shaft (MG3 shaft) 51.

[0011] In FIG. 1, only the components of the hybrid vehicle 1 that are necessary to realize the present invention are shown, and other components (e.g., ECU (Electronic Control Unit), battery, inverter, wheels, etc.) are not shown.

[0012] The engine 10 converts the combustion energy of fuel into the rotational motion of the output shaft 11 and outputs the rotational motion. The output shaft 11 is connected to a first carrier 22 of the power distribution mechanism 20 and transmits the rotational motion to the power distribution mechanism 20.

[0013] The power distribution mechanism 20 is disposed between the engine 10 and the axle 46 (wheels), and distributes the power of the engine 10 between the first motor-generator 30 and the second motor-generator 40 side and the axle 46 side (output side). The power distribution mechanism 20 has two single-pinion planetary gear mechanisms. The power distribution mechanism 20 also has a first rotation element, a second rotation element, a third rotation element, and a fourth rotation element that are capable of differential rotation relative to one another.

[0014] Specifically, power distribution mechanism 20 includes a first sun gear 21, a first carrier 22, a first ring gear 23, a first pinion gear 24, a second sun gear 25, a second carrier 26, a second ring gear 27, and a second pinion gear 28. Of the components of power distribution mechanism 20, first sun gear 21, first carrier 22, first ring gear 23, and first pinion gear 24 constitute a first planetary gear mechanism. Also, of the components of power distribution mechanism 20, second sun gear 25, second carrier 26, second ring gear 27, and second pinion gear 28 constitute a second planetary gear mechanism.

[0015] The first sun gear 21 is connected to the first motor generator 30. The first sun gear 21 functions as a "first rotating element" of the power distribution mechanism 20. The first carrier 22 is connected to the engine 10 via the output shaft 11. The first carrier 22 functions as a "second rotating element" of the power distribution mechanism 20.

[0016] The first ring gear 23 is connected to the second carrier 26. The first pinion gear 24 is rotatably supported by the first carrier 22, and is in mesh with the first sun gear 21 and the first ring gear 23, respectively.

[0017] Second sun gear 25 is connected to second motor-generator 40 via a rotating shaft 41. Second sun gear 25 functions as a "fourth rotating element" of power distribution mechanism 20. Second carrier 26 is connected to first ring gear 23. Second carrier 26 is also connected to axles 46 (wheels) via first ring gear 23, a counter driven gear 42, a counter shaft 43, a counter drive gear 44, and a differential 45. Second carrier 26 functions as a "third rotating element" of power distribution mechanism 20.

[0018] Second ring gear 27 is connected to first carrier 22. Second pinion gear 28 is rotatably supported by second carrier 26, and is in mesh with second sun gear 25 and second ring gear 27, respectively.

[0019] The first motor generator 30, the second motor generator 40, and the third motor generator 50 are connected to a battery (not shown) via an inverter (not shown). This inverter is configured with an electric circuit that enables the exchange of electric power between the motor generators. The third motor generator 50 is also coupled to an axle 46 (wheel) so as to be able to transmit power.

[0020] The counter driven gear 42 is connected to a counter drive gear 44 via a counter shaft 43. The counter driven gear 42 is also connected to a third motor generator 50 via a rotary shaft 51. The counter drive gear 44 meshes with a differential ring gear 45a of a differential 45. Wheels (drive wheels) (not shown) are connected to the differential 45 via left and right axles 46.

[0021] In the hybrid vehicle 1 equipped with the drive device as described above, it is possible to control the state of the hybrid vehicle 1 to a continuously variable transmission state. In this continuously variable transmission state, the speed ratio between the second rotating element (first carrier 22) and the third rotating element (second carrier 26) in the power split mechanism 20 is controlled continuously.

[0022] Also, in the drive device of the hybrid vehicle according to the embodiment, according to the engine torque and the speed ratio, the reaction force of the engine torque is controlled to be borne by at least one of the first motor generator 30 and the second motor generator 40.

[0023] FIG. 2 is a collinear diagram when the hybrid vehicle 1 is at a low vehicle speed (Ng1 ≧ Ng2) and has a high Te (high engine torque). FIG. 3 is a collinear diagram when the hybrid vehicle 1 is at a high vehicle speed (Ng1 < Ng2) and has a high Te (high engine torque). Here, "Ng1" represents the rotational speed of the first motor generator 30, "Ng2" represents the rotational speed of the second motor generator 40, and "Te" represents the engine torque. Also, in FIGS. 2 and 3, "S1" represents the first sun gear 21, "C1" represents the first carrier 22, "R1" represents the first ring gear 23, "S2" represents the second sun gear 25, "C2" represents the second carrier 26, and "R2" represents the second ring gear 27, respectively.

[0024] In the drive device of the hybrid vehicle according to the embodiment, as shown in FIGS. 2 and 3, when the engine torque is greater than or equal to a predetermined engine torque, the first motor generator 30 and the second motor generator 40 receive the reaction force of the engine torque.

[0025] FIG. 4 is a collinear diagram when the hybrid vehicle 1 is at a low vehicle speed (Ng1 ≧ Ng2) and has a low Te (low engine torque). FIG. 6 is a graph showing Tg (motor generator torque) with respect to Te (engine torque) when the vehicle speed is low (Ng1 ≧ Ng2).

[0026] Also, in FIG. 6, “Tg1” is the torque of the first motor generator 30, “Tg2” is the torque of the second motor generator 40, “ρ” is the gear ratio of the power distribution mechanism 20, “ρ1” is the gear ratio of the first planetary gear mechanism constituting the power distribution mechanism 20 (specifically, the value obtained by dividing the number of teeth of the first sun gear 21 by the number of teeth of the first ring gear 23), “ρ2” is the gear ratio of the first planetary gear mechanism constituting the power distribution mechanism 20 (specifically, the value obtained by dividing the number of teeth of the second sun gear 25 by the number of teeth of the second ring gear 27), and “Te_max” is the upper limit torque of the engine torque.

[0027] In the drive device of the hybrid vehicle according to the embodiment, as shown in FIGS. 4 and 6, when the engine torque is less than a predetermined engine torque and is greater than or equal to a predetermined gear ratio, the second motor generator 40 receives the reaction force of the engine torque.

[0028] FIG. 5 is a collinear diagram when the hybrid vehicle 1 has a high vehicle speed (Ng1 < Ng2) and a low Te (low engine torque). FIG. 7 is a graph showing Tg (motor generator torque) with respect to Te (engine torque) when the vehicle speed is high (Ng1 < Ng2).

[0029] As shown in FIGS. 5 and 7, when the engine torque is less than a predetermined engine torque and less than a predetermined gear ratio, the first motor generator 30 receives the reaction force of the engine torque.

[0030] (Operation) The operation of the drive device of the hybrid vehicle according to the embodiment will be described with reference to FIG. 8. The operation described in this figure is specifically implemented mainly by the ECU of the hybrid vehicle 1.

[0031] Also, in FIG. 8, "Ng1" is the rotational speed of the first motor generator 30, "Ng2" is the rotational speed of the second motor generator 40, "Te" is the engine torque, "Tg1_max" is the upper limit torque of the first motor generator 30, "Tg2_max" is the upper limit torque of the second motor generator 40, "ρ1" is the gear ratio of the first planetary gear mechanism constituting the power split mechanism 20 (specifically, the value obtained by dividing the number of teeth of the first sun gear 21 by the number of teeth of the first ring gear 23), and "ρ2" is the gear ratio of the two second planetary gear mechanism constituting the power split mechanism 20 (specifically, the value obtained by dividing the number of teeth of the second sun gear 25 by the number of teeth of the second ring gear 27).

[0032] First, it is determined whether it is "Ng1 ≧ Ng2" (step S1). In step S1, if it is determined that it is "Ng1 ≧ Ng2" (Yes in step S1), it is determined whether "Te < Tg2_max / (ρ1 / (ρ1 + 1))" (step S2).

[0033] In step S2, if it is determined that "Te < Tg2_max / (ρ1 / (ρ1 + 1))" (Yes in step S2), Tg1 is set to "0" and Tg2 is set to "Te * ρ2" (step S3), and this process is completed.

[0034] In step S2, if it is determined that "Te < Tg2_max / (ρ1 / (ρ1 + 1))" is not true (No in step S2), Tg1 is set to "(Te - Tg2_max * ρ2) * ρ1 / (ρ1 + 1)" and Tg2 is set to "Tg2_max" (step S4), and this process is completed.

[0035] In step S1, if it is determined that it is not "Ng1 ≧ Ng2" (No in step S1), it is determined whether "Te < Tg1_max / (ρ1 / (ρ1 + 1))" (step S5).

[0036] In step S5, if it is determined that "Te < Tg1_max / (ρ1 / (ρ1 + 1))" (Yes in step S5), set Tg1 to "Te*ρ1 / (ρ1 + 1)" and set Tg2 to "0" (step S6), and complete this process.

[0037] In step S5, if it is determined that "Te < Tg1_max / (ρ1 / (ρ1 + 1))" is not true (No in step S5), set Tg1 to "Tg1_max" and set Tg2 to "(Te - Tg1_max / (ρ1 / (ρ1 + 1)))*ρ2" (step S7), and complete this process.

[0038] In the drive device of the hybrid vehicle according to the embodiment described above, when the engine torque is above a predetermined value, the first motor generator 30 and the second motor generator 40 receive the reaction force of the engine torque. When the engine torque is less than the predetermined value and above a predetermined gear ratio, the second motor generator 40 receives the reaction force of the engine torque. When the engine torque is less than the predetermined value and less than the predetermined gear ratio, the first motor generator 30 receives the reaction force of the engine torque.

[0039] Thereby, since the maximum torque (upper limit torque) of the first motor generator 30 and the second motor generator 40 can be reduced, the cost of the entire system can be reduced.

[0040] Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various changes can be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

Explanation of Reference Signs

[0041] 1 Hybrid vehicle 10 Engine 11 Output shaft 20 Power distribution mechanism 21 First sun gear 22 First Carrier 23 First ring gear 24 First pinion gear 25 Second sun gear 26 Second Career 27 Second ring gear 28 Second pinion gear 30 First motor generator 40 Second motor generator 41 Rotation axis 42 Counter driven gear 43 Countershaft 44 Counter drive gear 45 differential 45a differential ring gear 46 axles 50 Third motor generator 51 Rotation axis

Claims

[Claim 1] a power distribution device provided in a power transmission path between the engine and the wheels, the power distribution device having a first rotation element, a second rotation element, a third rotation element and a fourth rotation element capable of differentially rotating relative to one another; the first motor generator and the first rotating element are connected to each other, the engine and the second rotating element are connected to each other, The wheel and the third rotating element are connected to each other, the second motor generator and the fourth rotating element are connected to each other, a drive device for a hybrid vehicle capable of continuously controlling a gear ratio between the third motor generator and the second rotating element and between the third motor generator and the second rotating element and the third rotating element, When the engine torque is equal to or greater than a predetermined engine torque, the engine torque is received by the first motor generator and the second motor generator; When the engine torque is less than a predetermined value and the gear ratio is equal to or greater than a predetermined value, the engine torque is received by the second motor generator; When the engine torque is less than a predetermined value and the gear ratio is less than a predetermined value, the engine torque is received by the first motor generator; receiving the engine torque by the second motor generator when the engine torque is less than a predetermined engine torque and is equal to or greater than a predetermined gear ratio means controlling the rotation speed of the second motor generator to Tg2=Te×ρ2 when the rotation speed of the first motor generator is equal to or greater than the rotation speed of the second motor generator and the engine torque is smaller than a predetermined value based on an upper limit torque of the second motor generator; receiving the engine torque by the first motor generator when the engine torque is less than a predetermined engine torque and less than a predetermined gear ratio means controlling the rotation speed of the first motor generator to Tg1=Te×ρ1 / (ρ1+1) when the rotation speed of the first motor generator is less than the rotation speed of the second motor generator and the engine torque is smaller than a predetermined value based on an upper limit torque of the first motor generator; Te is engine torque, ρ2 is a gear ratio of a second planetary gear mechanism constituting the power distribution device, and ρ1 is a gear ratio of a first planetary gear mechanism constituting the power distribution device. Hybrid vehicle drivetrain.

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