KR101231393B1

KR101231393B1 - power train of an hybrid electric vehicle and manipulating method thereof

Info

Publication number: KR101231393B1
Application number: KR1020060049745A
Authority: KR
Inventors: 조성태
Original assignee: 현대자동차주식회사
Priority date: 2006-06-02
Filing date: 2006-06-02
Publication date: 2013-02-07
Also published as: KR20070120625A

Abstract

According to the present invention, in a power train of a hybrid vehicle, it is possible to secure a wider speed ratio range with good power train efficiency, and operate the power train in a relatively efficient state in accordance with the change of the speed ratio. Make sure

Description

Dual-mode powertrain for hybrid electric vehicle and its operation method {power train of an hybrid electric vehicle and manipulating method

1 is a view showing the configuration of a dual-mode powertrain for a hybrid electric vehicle according to the present invention,

2 is a view illustrating a state in which the powertrain of FIG. 1 operates in a first mode;

3 is a view illustrating a state in which the powertrain of FIG. 1 operates in a second mode;

4 is a lever analysis of the powertrain of FIG.

5 is a lever analysis diagram illustrating a state of forming two mechanical points possible in the first mode;

6 is a lever analysis diagram illustrating a state in which two mechanical points are formed in the second mode;

7 is a graph showing the efficiency of the power train according to the transmission ratio in the case of controlling according to the control method of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

One; First carrier 3; Drive wheel

5; First ring gear 7; 1st Sun Gear

9; First planetary gearset 11; 2nd Sun Gear

13; Second carrier 15; 2nd motor generator

17; Second ring gear 19; 2nd planetary gear set

21; First motor generator 23; 3rd carrier

25; Third ring gear 27; 3rd Planetary Gear Set

29; First clutch 31; Second clutch

33; Power train case 22; 3rd Sun Gear

The present invention relates to a dual-mode powertrain for hybrid electric vehicles and a method of operating the same, and more particularly, to a technology for more efficient power transmission of a powertrain according to a vehicle transmission ratio.

A hybrid power transmission device using a planetary gear set and two motor generators can serve as an continuously actuated continuously variable transmission by controlling the speed of the motor generator without a separate transmission, and controlling the speed of the motor generator. Motor mode, engine mode, hybrid mode, and regenerative braking mode can be implemented, and the engine can be controlled on and off as needed to further improve fuel economy, and regenerative braking efficiency by minimizing the use of friction brakes during braking. Can increase.

Conventionally, a method widely used as a power train for a hybrid electric vehicle using two motor generators has an input split type structure in which one of the two motor generators is fixedly connected to the output shaft.

The power train having the above structure has the best efficiency at the gear ratio which forms a mechanical point at which the speed of the remaining motor generator, which is not directly connected to the output shaft, becomes zero, and if the gear ratio increases or decreases, the efficiency is the highest. This starts to fall, and the decrease in efficiency when the speed ratio decreases is sharply larger than when the speed ratio increases.

That is, as the speed ratio decreases beyond the mechanical point (as the vehicle speed increases), there is a problem in that the efficiency of the power train decreases rapidly.

The present invention has been devised in view of the above-described problems, and it is possible to secure a wider speed ratio range of the power train more efficiently, and operate the power train in a relatively efficient state according to the change of the speed ratio. The purpose of the present invention is to provide a dual mode powertrain for hybrid electric vehicles and a method of operating the same.

The dual mode powertrain for a hybrid electric vehicle of the present invention for achieving the above object is

A first planetary gear set having a first carrier connected to the engine, a first ring gear connected to the driving wheel, and a first sun gear;

A second planetary gear set including a second sun gear connected to a first ring gear of the first planetary gear set, a second carrier connected to the first sun gear, and a second ring gear connected to a second motor generator;

A third planetary gear set including a third sun gear connected to a first motor generator, a third carrier connected to the second carrier, and a third ring gear;

A first clutch provided to connect and disconnect the second ring gear of the second planetary gear set and the third ring gear of the third planetary gear set;

A second clutch installed to convert the third ring gear of the third planetary gear set into a fixed state and a rotatable state;

And a control unit.

In addition, the operating method of the dual mode powertrain for a hybrid electric vehicle of the present invention

The first clutch is connected and the second clutch is disconnected in a region with a high speed ratio based on the mechanical point at which the speed of the second motor generator becomes zero. In the region where the speed ratio is low, the first clutch is disconnected and the second clutch is disconnected. It is characterized by connecting two clutches.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Referring to FIG. 1, a power train according to an embodiment of the present invention includes a first carrier 1 connected to an engine, a first ring gear 5 connected to a driving wheel 3, and a first sun gear 7. A planetary gear set 9; A second sun gear 11 connected to the first ring gear 5 of the first planetary gear set 9, a second carrier 13 connected to the first sun gear 7, and a second motor generator 15. A second planetary gear set 19 having a second ring gear 17 connected thereto; A third planetary gear set including a third sun gear 22 connected to the first motor generator 21, a third carrier 23 connected to the second carrier 13, and a third ring gear 25 ( 27); A first clutch 29 installed to connect and disconnect the second ring gear 17 of the second planetary gear set 19 and the third ring gear 25 of the third planetary gear set 27; ; And a second clutch 31 installed to switch the third ring gear 25 of the third planetary gear set 27 to a fixed state and a rotatable state.

In the present exemplary embodiment, the second clutch 31 is installed between the power train case 33 and the third ring gear 25 of the third planetary gear set 27 to connect the third ring gear 25. The power train case 33 can be switched between a fixed state and a rotatable state.

Of course, the second clutch 31 may be installed between the vehicle body part and the third ring gear 25 instead of the power train case 33.

The first planetary gear set 9, the second planetary gear set 19 and the third planetary gear set 27 are all composed of a single pinion planetary gear.

The power train configured as described above may be operated in a first mode and a second mode, which are compound split modes according to the states of the first clutch 29 and the second clutch 31.

Hereinafter, a case in which the first clutch 29 is in a connected state and the second clutch 31 is in a disconnected state as shown in FIG. 2 will be referred to as a first mode, and the first clutch 29 is in a disconnected state as shown in FIG. The case where the second clutch 31 is in the connected state is referred to as a second mode.

The power train is expressed in lever analysis as shown in FIG. 4, and a part of the state in which the power train is operated in the first mode is shown in FIG. 5. In FIG. 5, the upper side shows the case of the transmission ratio which forms the mechanical point M1-1 whose speed of the 2nd motor generator 15 is 0, and the lower side has 0 the speed of the 1st motor generator 21. In FIG. The case of the transmission ratio which forms the mechanical point M1-2 is shown by comparison.

That is, in the state in which the powertrain of the present invention is in the first mode, it has two mechanical points M1-1 and M1-2 shown in FIG. 5 in accordance with the change of the speed ratio; The battery is not interposed between the first motor generator 21 and the second motor generator 15, and electricity generated on one side is consumed on the other side, so that the sum of the amount of power generated and the consumption is zero, and the speed of the motor generator is zero. Under the condition of ignoring energy loss to maintain, the efficiency at the two mechanical points becomes a maximum of 1; This can be confirmed in the efficiency graph of the power train according to the shift ratio of FIG. 7.

In FIG. 7, the curve representing the efficiency of the first mode is illustrated as having a maximum value of 1, and two mechanical points (M1-M) that the powertrain has in the first mode have two positions where the efficiency is the maximum value. 1, M1-2), and it turns out that efficiency falls rapidly as a speed ratio becomes small from the position indicated by the mode change point.

For reference, in Figures 4 to 6, O = output, I = input (engine), MG1 = first motor generator 21, MG2 = second motor generator 15, respectively,

I is 1 unit distance from O,

The distance that MG1 is

, The distance MG2 is from O

In the first mode,

= -0.625,

= 3.75 and in the second mode

= 2.5,

It is located at = 3.75. Thus, both the first mode and the second mode

Wow

Since is not zero (0), it can be seen that all of them are in compound branch mode.

Of course, the distance that the I, MG1, MG2 is away from the O corresponds to the gear ratio in the actual powertrain.

On the other hand, the graph of Figure 7 is shown by the following equation (1).

here,

Powertrain efficiency,

,

Is the above value for each mode,

Speed ratio

,

Is the efficiency when the first motor generator 21 and the second motor generator 15 are charged and discharged, respectively, where values of 0.949 and 1 / 0.949 are used, and values smaller than 1 are used for charging. (0.949 here) and a value greater than 1 (1 / 0.949 here) at the time of discharge.

Part of the state in which the powertrain is operated in the second mode is represented as shown in FIG. 6. In FIG. 6, the upper side shows a case of a transmission ratio forming a mechanical point M2-1 in which the speed of the second motor generator 15 is zero, and the lower side has a speed of 0 in the first motor generator 21. The case of the transmission ratio which forms the mechanical point M2-2 is shown by comparison.

That is, in the state in which the powertrain of the present invention is in the second mode, it has two mechanical points M2-1 and M2-2 shown in FIG. 6 in accordance with the change of the speed ratio; The battery is not interposed between the first motor generator 21 and the second motor generator 15, and electricity generated on one side is consumed on the other side, so that the sum of the amount of power generated and the consumption is zero, and the speed of the motor generator is zero. Under the condition of ignoring energy loss to maintain, the efficiency at the two mechanical points becomes a maximum of 1; This can be confirmed in the efficiency graph of the power train according to the shift ratio of FIG. 7.

In FIG. 7, the curve representing the efficiency of the second mode is shown in a state having 1, the maximum value of 2, and two mechanical points (M2-) that the powertrain has in the second mode have two positions where the efficiency is the maximum value. 1, M2-2), where the efficiency of the first mode is the maximum while the efficiency of the second mode is the maximum at the position indicated by the mode change point. It can be seen that the coincidence of the second mode is that the point M2-2 at which the remaining efficiency is the maximum value is located on the left side of the mode change point, so that the efficiency of the second mode is higher than the first mode in the range on the left side of the mode change point. Can be.

Meanwhile, the mode change point corresponds to a speed ratio in which the speed of the second motor generator 15 becomes 0 in the first mode, and corresponds to a speed ratio in which the speed of the second motor generator 15 is 0 in the second mode. do.

Therefore, in the present invention, the first clutch 29 is connected and the second clutch 31 is connected in a region where the speed ratio is high based on the mode change point, which is a mechanical point at which the speed of the second motor generator 15 becomes zero. By operating in the first mode by disconnecting the first clutch 29 in the low speed ratio region, by operating the second mode by disconnecting the first clutch 29 and connecting the second clutch 31, the speed ratio region having a good powertrain efficiency can be obtained. In addition to ensuring a wide range, it also allows the powertrain to operate in a relatively efficient state as the speed ratio changes.

Therefore, the first mode is used in a section in which a high speed ratio of a power train is required because the vehicle speed is relatively low, and the second mode is used in a section in which a low speed ratio of the power train is required because the vehicle speed is relatively high. will be.

In the first and second modes, the first motor generator 21 and the second motor generator 15 alternately perform charging and discharging according to the speed ratio of the power train, and the first motor generator 21. Alternatively, the power generated by the second motor generator 15 is combined with the power of the engine and provided to the driving wheel 3.

As described above, according to the present invention, in a power train of a hybrid vehicle, it is possible to secure a wider speed ratio range with a good power train efficiency, and to maintain a relatively high efficiency of the power train as the speed ratio changes. Make it work.

In addition, as described above, by selecting and operating a state in which the power train has good efficiency, the mechanical load that the first motor generator and the second motor generator have to deal with can be reduced to the maximum, and thus a motor generator having a relatively small capacity can be used. To help.

Claims

Dual mode powertrain for a hybrid electric vehicle, characterized in that configured to include.

The method according to claim 1,

The second clutch is installed between the power train case and the third ring gear of the third planetary gear set.

Dual mode powertrain for hybrid electric vehicles, characterized in that.

The method according to claim 1,

The first planetary gear set, the second planetary gear set, and the third planetary gear set are single pinion planetary gears.

Dual mode powertrain for hybrid electric vehicles, characterized in that.

In the method of controlling the powertrain of claim 1,

The first clutch is connected and the second clutch is disconnected in a region with a high speed ratio based on the mechanical point at which the speed of the second motor generator becomes zero. In the region where the speed ratio is low, the first clutch is disconnected and the second clutch is disconnected. Connecting two clutches

Dual mode powertrain operation method for a hybrid electric vehicle characterized in that.