JP2011057114A - Power output device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively improve fuel economy when traveling by dividing the power of an engine into a drive shaft side and a first MG (motor generator) side with a planetary gear mechanism. <P>SOLUTION: The power of an engine 10 is divided into a sun gear shaft 18 and a ring gear shaft 19 with a first planetary gear mechanism 14. Furthermore, the power of the sun gear shaft 18 is divided into a sun gear shaft 24 and a ring gear shaft 25 with a second planetary gear mechanism 20, and the ratio of power transmitted from the engine 10 to the first MG 11 side is made small by transmitting the power of the sun gear shaft 24 to the first MG 11. On the other hand, both powers of the ring gear shaft 19 of the first planetary gear mechanism 14 and the ring gear shaft 25 of the second planetary gear mechanism 20 are transmitted to a drive shaft 26, and thereby the ratio of power transmitted from the engine 10 to the drive shaft 26 side is made large. Thus, the electric loss of the MG 11, 12 and inverters 31, 32 is reduced, and the energy loss of the whole vehicle is reduced. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power output apparatus for a vehicle equipped with an internal combustion engine, a motor, and a generator.

  In recent years, the demand for hybrid vehicles has increased due to the social demand for low fuel consumption and low exhaust emissions. Currently, in a hybrid vehicle that is commercially available, for example, as described in Patent Document 1 (Japanese Patent Laid-Open No. 2001-329884), an internal combustion engine, a motor, and a generator are mounted, and the power of the internal combustion engine is increased. The system is divided into two systems by a power split mechanism (for example, planetary gear mechanism), the drive shaft is driven by the output of one system to drive the wheels, and the generator is driven by the output of the other system to generate power by the generator. There is a split type hybrid vehicle in which a motor is driven by the generated power or battery power and the wheels are driven by the power of the motor.

JP 2001-329884 A

  In the conventional split type hybrid vehicle, the power split ratio (the ratio between the number of teeth of the sun gear and the number of teeth of the ring gear) of the power split mechanism (for example, the planetary gear mechanism) is transmitted to the drive shaft side from the internal combustion engine. The ratio between the power to be transmitted and the power transmitted to the generator is determined), but the planetary ratio (that is, the power split ratio) is within the range that allows the power split mechanism to fit within the vehicle. Therefore, there is a problem that the ratio of power transmitted from the internal combustion engine to the generator side cannot be sufficiently reduced. For this reason, when the power of the internal combustion engine is divided into the drive shaft side and the generator side by the power split mechanism and travels, the ratio of the power transmitted from the internal combustion engine to the generator side can be sufficiently reduced. In addition, the electrical output of the generator and the inverter that drives it cannot be reduced, the electrical loss increases, the energy loss of the entire vehicle increases, and a dramatic improvement in fuel efficiency cannot be expected, and the fuel efficiency is sluggish. It was an adverse effect of downsizing and cost reduction.

  Therefore, the problem to be solved by the present invention is that the ratio of power transmitted from the internal combustion engine to the generator side can be sufficiently reduced, and the fuel efficiency is effectively improved and the inverter and generator are reduced in size and low. An object of the present invention is to provide a power output device for a vehicle that can be reduced in cost.

  In order to solve the above-mentioned problem, the invention according to claim 1 is the first mechanical transmission as a power transmission path for outputting the power of the internal combustion engine in the vehicle power output device including the internal combustion engine, the motor, and the generator. It is configured to have at least a road, a second mechanical transmission path, and an electrical transmission path.

  Specifically, as in claim 2, the first power dividing means for dividing the power of the internal combustion engine into the first power transmission path and the second power transmission path, and the power of the first power transmission path Is divided into a third power transmission path and a fourth power transmission path, and the first power transmission path is used as the first mechanical transmission path, and the second power transmission. The fourth power transmission path is defined as the second mechanical transmission path via the path, the second power transmission path and the fourth power transmission path are coupled, and the motor and the vehicle are driven in the second power transmission path. The shaft may be connected, and a generator may be connected to the third power transmission path to provide an electric transmission path that can transmit power between the generator and the motor.

  In this configuration, the power of the internal combustion engine is divided into two systems of the first power transmission path and the second power transmission path by the first power split means, and further, the power of the first power transmission path is divided into the second power. Can be divided into two systems of a third power transmission path and a fourth power transmission path, and the power of the third power transmission path can be transmitted to the generator. The ratio of the power transmitted to the machine side can be reduced, and on the other hand, both the power of the second power transmission path and the power of the fourth power transmission path can be transmitted to the drive shaft. The ratio of power transmitted from the drive shaft to the drive shaft can be increased. As a result, when the power of the internal combustion engine is divided into the drive shaft side and the generator side by the power split mechanism, the ratio of the power transmitted from the internal combustion engine to the generator side can be sufficiently reduced. Because the electrical output of the generator and the inverter that drives it can be reduced, they can be reduced in size and cost, and the electrical loss can be reduced to reduce the energy loss of the entire vehicle. Can be improved effectively.

FIG. 1 is a schematic configuration diagram of an entire vehicle drive system according to an embodiment of the present invention. FIG. 2 is a collinear diagram showing the relationship between the rotational speeds of the respective parts.

Hereinafter, an embodiment embodying a mode for carrying out the present invention will be described.
First, a schematic configuration of the entire vehicle drive system will be described with reference to FIG.
An internal combustion engine 10, a first motor generator (generator: hereinafter referred to as “first MG”) 11, and a second motor generator (hereinafter referred to as “second MG”) 12 are mounted. The engine 10 and the second MG 12 are mainly power sources that drive the wheels 29. The second MG 12 corresponds to a motor in the claims.

  The power of the crankshaft 13 of the engine 10 is divided into two systems by the first planetary gear mechanism 14 (first power split means). The first planetary gear mechanism 14 includes a sun gear 15 that rotates at the center, a planetary gear 16 that revolves while rotating on the outer periphery of the sun gear 15, and a ring gear 17 that rotates on the outer periphery of the planetary gear 16. Is connected to the crankshaft 13 of the engine 10 via a carrier (not shown), and the sun gear 15 is connected to a sun gear shaft 18 as a first power transmission path (first mechanical transmission path). Is connected to a ring gear shaft 19 which is a second power transmission path (second mechanical transmission path). Thereby, the power of the crankshaft 13 of the engine 10 is divided and transmitted to the sun gear shaft 18 and the ring gear shaft 19 by the first planetary gear mechanism 14.

  Further, the power of the sun gear shaft 18 of the first planetary gear mechanism 14 is divided into two systems by the second planetary gear mechanism 20 (second power dividing means). The second planetary gear mechanism 20 includes a sun gear 21 that rotates at the center, a planetary gear 22 that revolves while rotating on the outer periphery of the sun gear 21, and a ring gear 23 that rotates on the outer periphery of the planetary gear 22. Is connected to the sun gear shaft 18 of the first planetary gear mechanism 14 via a carrier (not shown), the sun gear 21 is connected to the sun gear shaft 24 as a third power transmission path, and the ring gear 23 is connected to the first gear mechanism. A ring gear shaft 25 that is a power transmission path (second mechanical transmission path) 4 is connected. Thereby, the power of the sun gear shaft 18 of the first planetary gear mechanism 14 is divided and transmitted to the sun gear shaft 24 and the ring gear shaft 25 by the second planetary gear mechanism 20.

  Further, the ring gear shaft 19 of the first planetary gear mechanism 14 and the ring gear shaft 25 of the second planetary gear mechanism 20 are connected, and the ring gear shaft 19 of the first planetary gear mechanism 14 is connected to the second gear MG 12. The rotating shaft and the drive shaft 26 of the vehicle are connected, and the power of the drive shaft 26 is transmitted to the wheels 29 via the differential gear 27, the axle 28, and the like. Further, the sun gear shaft 24 of the second planetary gear mechanism 20 is connected to the rotation shaft of the first MG 11 mainly used as a generator. The first MG 11 corresponds to the generator referred to in the claims.

  In addition, a first inverter 31 that drives the first MG 11 and a second inverter 32 that drives the second MG 12 are provided, and the MGs 11 and 12 are connected to each other via the inverters 31 and 32, respectively. An electric transmission path capable of mutually transmitting power between the first MG 11 and the second MG 12 is formed, and each MG 11, 12 also receives power from the battery 33. It is like that.

  The vehicle ECU 34 is a computer that comprehensively controls the entire vehicle, and detects an accelerator sensor 35 that detects an accelerator operation amount (an accelerator pedal operation amount), a shift switch 36 that detects a shift lever operation position, and a brake operation. The output signals of various sensors such as the brake switch 37 and the switch are read to detect the driving state of the vehicle. The vehicle ECU 34 controls an engine ECU 38 that controls the operation of the engine 10, a first MG-ECU 39 that controls the first inverter 31 to control the first MG 11, and a second inverter 32 that controls the second inverter 32. Control signals and data signals are transmitted to and received from the second MG-ECU 40 that controls the second MG 12, and the ECUs 38 to 40 transmit the engine 10, the first MG 11, and the second MG 12 according to the driving state of the vehicle. Control.

  For example, at the time of starting or at a low load (a region where the fuel efficiency of the engine 10 is poor), the engine 10 is maintained in a stopped state, the second MG 12 is driven by the power of the battery 33, and the power of the second MG 12 is Only by driving the wheels 29, the motor travels.

  During normal travel, the power of the crankshaft 13 of the engine 10 is divided into two systems of the sun gear shaft 18 and the ring gear shaft 19 by the first planetary gear mechanism 14, and further the power of the sun gear shaft 18 of the first planetary gear mechanism 14. Is divided into two systems of a sun gear shaft 24 and a ring gear shaft 25 by the second planetary gear mechanism 20. Then, by transmitting both the power of the ring gear shaft 19 of the first planetary gear mechanism 14 and the power of the ring gear shaft 25 of the second planetary gear mechanism 20 to the drive shaft 26, the drive shaft 26 is driven and the wheels 29 are moved. To drive. Further, the power of the sun gear shaft 24 of the second planetary gear mechanism 20 is transmitted to the first MG 11 to drive the first MG 11 to generate power by the first MG 11, and the generated MG 12 generates the second MG 12. The drive shaft 26 is driven by the driving power of the second MG 12 to drive the wheels 29. Further, at the time of rapid acceleration or the like, the power of the battery 33 is supplied to the second MG 12 in addition to the generated power of the first MG 11 to increase the driving amount of the second MG 12.

  During deceleration, the second MG 12 is driven by the power of the wheels 29 and the second MG 12 is operated as a generator so that the kinetic energy of the vehicle is converted into electric power by the second MG 12 and the battery 33 is charged. to recover.

  Here, FIG. 2 shows the rotational speed Ne of the crankshaft 13 of the engine 10 connected to the carrier of the planetary gear 16 of the first planetary gear mechanism 14 and the rotational speed Ns1 of the sun gear shaft 18 of the first planetary gear mechanism 14. (= The rotational speed Nc2 of the planetary gear 22 carrier of the second planetary gear mechanism 20) and the rotational speed Np of the drive shaft 26 connected to the ring gear shafts 19 and 25 of the first and second planetary gear mechanisms 14 and 20. And a nomographic chart showing the relationship between the rotational speed Ng of the first MG 11 connected to the sun gear shaft 24 of the second planetary gear mechanism 20, and the rotational speeds are connected in a straight line.

The torque Te of the engine 10 is divided and transmitted to the sun gear shaft 18 and the ring gear shaft 19 by the first planetary gear mechanism 14. At this time, the torque Ts1 transmitted to the sun gear shaft 18 and the torque Tr1 transmitted to the ring gear shaft 19 are respectively the torque Te of the engine 10 and the planetary ratio ρ1 of the first planetary gear mechanism 14 (the number of teeth of the sun gear 15 and the ring gear). 17) and the following formulas (1) and (2).
Ts1 = Te × ρ1 / (1 + ρ1) (1)
Tr1 = Te / (1 + ρ1) (2)

Further, the torque Ts1 of the sun gear shaft 18 of the first planetary gear mechanism 14 is divided and transmitted to the sun gear shaft 24 and the ring gear shaft 25 by the second planetary gear mechanism 20. At this time, the torque Ts2 transmitted to the sun gear shaft 24 and the torque Tr2 transmitted to the ring gear shaft 25 are the torque Ts1 of the sun gear shaft 18 of the first planetary gear mechanism 14 and the planetary ratio of the second planetary gear mechanism 20, respectively. Using ρ2 (ratio of the number of teeth of the sun gear 21 and the number of teeth of the ring gear 23), it can be expressed by the following equations (3) and (4).
Ts2 = Ts1 × ρ2 / (1 + ρ2) (3)
Tr2 = Ts1 / (1 + ρ2) (4)

From the above equations (1) and (3), the torque Ts2 transmitted to the sun gear shaft 24 of the second planetary gear mechanism 20 can be expressed by the following equation (5).
Ts2 = Te × ρ1 / (1 + ρ1) × ρ2 / (1 + ρ2) (5)

Since the torque Ts2 of the sun gear shaft 24 of the second planetary gear mechanism 20 acts on the first MG11, the relationship between the torque Tg of the first MG11 and the torque Ts2 of the sun gear shaft 24 of the second planetary gear mechanism 20 Can be expressed by the following equation (6).
Tg + Ts2 = 0 (6)

  As a result, the ratio of torque transmitted from engine 10 to first MG 11 can be reduced as compared with a conventional system (a system including only one planetary gear mechanism that divides engine power).

On the other hand, both the torque Tr1 transmitted to the ring gear shaft 19 of the first planetary gear mechanism 14 and the torque Tr2 transmitted to the ring gear shaft 25 of the second planetary gear mechanism 20 out of the torque Te of the engine 11 are driven shafts 26. In addition, since the torque Tm of the second MG 12 is also transmitted to the drive shaft 26, the torque Tp transmitted to the drive shaft 26 can be expressed by the following equation (7).
Tp = Tr1 + Tr2 + Tm (7)

The torque Tp transmitted to the drive shaft 26 from the above equations (1), (2), (4), and (7) can be expressed by the following equation (8).
Tp = Te / (1 + ρ1) + Te × ρ1 / (1 + ρ1) / (1 + ρ2) + Tm (8)

  Thereby, the ratio of the torque transmitted from the engine 10 to the drive shaft 26 can be increased as compared with a conventional system (a system including only one planetary gear mechanism that divides engine power).

  In general, the power of the engine 10 is transmitted to the first MG 11, and the power of the engine 10 is less than the loss when the second MG 12 is driven by the power generated by the first MG 11 to drive the drive shaft 26. Since the loss when the drive shaft 26 is mechanically transmitted to the drive shaft 26 is smaller, the ratio of the power transmitted from the engine 10 to the first MG 11 side is reduced so that the drive shaft is driven from the engine 10. Power transmission efficiency can be improved by increasing the ratio of the torque transmitted to 26.

  In the present embodiment described above, the power of the engine 10 is divided into two systems of the sun gear shaft 18 and the ring gear shaft 19 by the first planetary gear mechanism 14, and the power of the sun gear shaft 18 of the first planetary gear mechanism 14 is further divided. Can be divided into two systems of the sun gear shaft 24 and the ring gear shaft 25 by the second planetary gear mechanism 20 and the power of the sun gear shaft 24 can be transmitted to the first MG 11. The ratio of the power transmitted to the side can be reduced, while the power of the ring gear shaft 19 of the first planetary gear mechanism 14 and the power of the ring gear shaft 25 of the second planetary gear mechanism 20 are both driven by the drive shaft 26. Therefore, the ratio of the power transmitted from the engine 10 to the drive shaft 26 side can be increased.

  As a result, the ratio of the power transmitted from the engine 10 to the first MG 11 side when the power of the engine 10 is divided by the planetary gear mechanisms 14 and 20 into the drive shaft 26 side and the first MG 11 side. Can be made sufficiently small, the electric loss in the first MG 11 and the second MG 12 and the inverters 31 and 32 that drive them can be reduced, the energy loss of the entire vehicle can be reduced, and the fuel efficiency can be reduced. It can be improved effectively.

  In the above embodiment, the engine 10 and the planetary gear 16 carrier of the first planetary gear mechanism 14 are connected, and the sun gear 15 of the first planetary gear mechanism 14 and the carrier of the planetary gear 22 of the second planetary gear mechanism 20 are connected. And the ring gear 19 of the first planetary gear mechanism 14 and the ring gear 25 of the second planetary gear mechanism 20 and the ring gear 19 of the first planetary gear mechanism 14, the second MG 12, and the drive shaft 26. And the sun gear 21 of the second planetary gear mechanism 20 and the first MG 11 are connected to each other, but the engine 10, the MGs 11, 12 and the drive shaft 26 are connected via the planetary gear mechanisms 14, 20. The connection method is not limited to the method of the above embodiment, and may be changed as appropriate according to the mounting space of the drive system and the drive method (for example, FF method, FR method, RR method). It may be.

  In the above embodiment, two planetary gear mechanisms are provided and the engine power is divided in two stages. However, as another embodiment, three or more planetary gear mechanisms are provided and the engine power is provided in three stages. You may make it divide | segment by the above.

  DESCRIPTION OF SYMBOLS 10 ... Engine (internal combustion engine), 11 ... 1st MG (generator), 12 ... 2nd MG (motor), 14 ... 1st planetary gear mechanism (1st power division means), 18 ... Sun gear shaft (First power transmission path), 19 ... ring gear shaft (second power transmission path), 20 ... second planetary gear mechanism (second power split means), 24 ... sun gear shaft (third power transmission path) ), 25 ... Ring gear shaft (fourth power transmission path), 26 ... Drive shaft, 29 ... Wheel, 31, 32 ... Inverter, 33 ... Battery, 34 ... Vehicle ECU, 38 ... Engine ECU, 39, 40 ... MG- ECU

Claims (2)

In a vehicle power output device including an internal combustion engine, a motor, and a generator,
A power output apparatus for a vehicle, comprising at least a first mechanical transmission path, a second mechanical transmission path, and an electrical transmission path as a power transmission path for outputting the power of the internal combustion engine. A first power dividing means for dividing the power of the internal combustion engine into a first power transmission path and a second power transmission path; a power of the first power transmission path; a third power transmission path and a fourth power transmission path; A second power split means for splitting the power transmission path of
The first power transmission path is the first mechanical transmission path, and the fourth power transmission path is the second mechanical transmission path via the second power transmission path.
The second power transmission path is connected to the fourth power transmission path, the motor and a drive shaft of the vehicle are connected to the second power transmission path, and the third power transmission path is connected to the third power transmission path. The power output apparatus for a vehicle according to claim 1, further comprising: an electric transmission path that is connected to a generator and is capable of mutually transmitting electric power between the generator and the motor.

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