WO2009146820A2

WO2009146820A2 - Hybrid drive system

Info

Publication number: WO2009146820A2
Application number: PCT/EP2009/003747
Authority: WO
Inventors: Richard Bauer; Alexander Mark
Original assignee: Robert Bosch Gmbh
Priority date: 2008-06-03
Filing date: 2009-05-27
Publication date: 2009-12-10
Also published as: DE102008026515A1; WO2009146820A3

Abstract

The invention relates to a hybrid drive system (1) having a primary aggregate (2) and a hydraulic machine (34), wherein each are connected to a drive shaft (8, 44). The primary aggregate (1) drives a hydraulic pump (10) by means of the drive shaft (8), the hydraulic machine (34) being hydraulically coupled to the hydraulic pump. The drive shafts (8, 44) can thereby be mechanically coupled.

Description

description

Hvbridantrieb

The invention relates to a hybrid drive according to the preamble of claim 1.

A hybrid drive is a combination of different drive principles or different energy sources for a drive task within an application, for example a vehicle.

Depending on the arrangement and the mechanical connection of the drive machines, a distinction is made between serial hybrid drive and parallel hybrid drive. In a serial hybrid, the entire power of the internal combustion engine via an electric generator or a hydraulic pump is converted into electrical / hydraulic energy and the drive of the vehicle takes place exclusively by an electric or hydraulic motor. The disadvantage here is that this drive has a very poor efficiency at high speeds of the vehicle and low loads.

In a parallel hybrid are two prime movers, such as an electric motor or hydraulic motor and an internal combustion engine, with a final drive in conjunction, so that the relevant vehicle with appropriate training and arrangement of the drive train, separate from the electric motor or hydraulic motor, separate from the internal combustion engine, or can be driven jointly by both prime movers.

US Pat. No. 5,495,912 discloses a parallel hybrid in which an internal combustion engine transmits energy to a drive shaft to which a hydraulic unit is connected, which can be operated as a hydraulic pump or hydraulic motor and from which a drive unit (transmission, wheels etc.) is connected. a vehicle is driven. The hydro unit is a hydraulic accumulator in operative connection, the energy to the hydraulic motor or can absorb energy from the hydraulic pump. To the shop the hydraulic accumulator either the braking energy of the vehicle and thus indirectly the internal combustion engine is used, which must supply a part of the acceleration energy before braking, or it is used directly to drive the internal combustion engine for the hydraulic pump. In addition to the internal combustion engine, another internal combustion engine can be connected to the drive shaft in order to increase the performance of the parallel hybrid. This solution has the disadvantage that this drive has a very complex structure and high production costs.

In contrast, the invention has for its object to provide a hybrid drive, which has a high efficiency and is compact.

This object is achieved by a hybrid drive with the features of claim 1.

According to the invention, a hybrid drive has at least one primary unit and one hydraulic machine, these being in operative connection with a first drive shaft and the primary unit with a second drive shaft. Via the second drive shaft, a hydraulic pump connected to the hydraulic machine is driven. The first and the second drive shaft can be connected via a coupling.

This solution has the advantage that several drive principles are made possible by this hybrid drive. In the open state of the clutch, the hybrid drive can be operated serially. When the clutch is closed, the hybrid drive can be used either in parallel or as a primary drive unit. Thus, the hybrid drive can be flexibly optimally adapted to different operating conditions with a simultaneously high efficiency.

The hydraulic machine and the first drive shaft are advantageously connected via a transmission, whereby the torque and the rotational speed between the hydraulic machine and the drive shaft can be adjusted. The transmission of the hydraulic machine can be designed in one stage, two-stage or planetary gear and is thus ideally adaptable to the application of the hybrid drive.

Preferably, the primary unit is an internal combustion engine (VKM), which can have a high performance and a high efficiency.

The VKM is connected in one embodiment of the invention via a single-stage motor gearbox with the second drive shaft, wherein the motor gearbox has very compact dimensions and is inexpensive to produce.

Via a valve block, a pressure connection of the hydraulic pump can be connected to a high-pressure accumulator or a high-pressure connection of the hydraulic motor and via the suction connection to a low-pressure accumulator or to a low-pressure connection of the hydraulic motor. Furthermore, the high-pressure accumulator can be connected to the high-pressure connection of the hydraulic motor and the low-pressure accumulator to the low-pressure connection via the valve block. be connectable to the hydraulic motor. As a result, different operating states of the hydraulic pump and the hydraulic motor are easily adjustable via the valve block.

Advantageously, with a control unit, the VKM, the hydraulic machine, the hydraulic pump, the clutch, the valve block, a gear unit and a planetary gear can be controlled via, for example, electrical control lines. Thus, an optimal adaptation of the hybrid drive to a variety of operating ranges allows, so that a high efficiency can be achieved.

The hydraulic machine and the pump can be adjusted and thus operated with different speeds and torques.

The hydromachine can be used extremely flexibly in 4-quadrant operation as a hydraulic pump and motor with different directions and torques of rotation. - A -

The first drive shaft can be in operative connection with a differential gear and a wheel drive arranged thereon, for example, in order to drive a vehicle.

Other advantageous developments of the invention are the subject of further subclaims.

In the following, preferred embodiments of the invention will be explained in more detail with reference to schematic drawings. Show it:

1 shows a hybrid drive according to a first embodiment;

2 shows a hybrid drive according to a second embodiment;

3 is a tensile diagram of the hybrid drive according to the second embodiment; and

4 shows a hybrid drive according to a third embodiment.

1 shows a hybrid drive 1, for example for a motor vehicle, shown in a schematic representation according to a first embodiment. This has an internal combustion engine 2 (VKM), which is connected via a drive shaft 4 and a motor gear in the form of a gear pair 6 with a first drive shaft 8, which drives an adjustable hydraulic pump 10. The hydropump 10 has a pressure port 12, which is connected via a pressure line 14 to a valve block 16. A suction port 18 of the hydraulic pump 10 is also connected via a suction line 20 to the valve block 16.

The valve block 16 is different adjustable. In a first position of the valve block 16, the hydraulic pump 10 driven by the VKM 2 delivers pressure medium from a low-pressure reservoir 24 via a first storage line 22, the suction line 20, the pressure line 14 and a second storage line 26 to a high pressure accumulator 28, thus storing hydraulic energy therein becomes. In a second position of the valve block 16, the hydraulic pump 10 is in fluid communication with a hydromaschine 34, supplied from the pressure line 14 and a high-pressure line 30 which is connected to a high-pressure port 32 of the hydraulic machine 34, this with pressure medium and this via a a low pressure port 36 of the hydraulic machine 34 connected low pressure line 38 and the suction line 20 is returned to the hydraulic pump 10. The hydraulic machine 34 acts as a hydraulic motor 34.

In a third position of the valve block 16, the hydraulic machine 34 is connected to the low and high pressure accumulator 24, 28 and thus independently of the hydraulic pump 10 as a hydraulic motor 34 operable. In this case, pressure medium flows from the high-pressure accumulator 28 via the second accumulator line 26, the high-pressure line 30 and the high-pressure port 32 to the hydraulic motor 34 and is returned to the low-pressure accumulator 24 via the low-pressure port 36, the low-pressure line 38 and the first accumulator line 22. On the other hand, if the hydromachine 34 is used as a hydraulic pump 34 (described in more detail later in the description), this pressure medium conveys from the low to the high-pressure accumulator 24, 28. By a four-quadrant operation, the hydraulic machine 34 can be operated flexibly with changing direction of rotation and changing moment direction.

The hydraulic machine 34 is operatively connected to a second drive shaft 44 via a drive shaft 40 and a gear designed as a gear pair 42. This drives via a differential gear 46 two output shafts 48 with wheels 50 at.

The first and second drive shaft 8, 44 are mechanically connectable via a coupling 52, which is arranged between the connected to the drive shafts 8, 44 gear pairs 6, 42.

A controller 54 is electrically connected via a branching control line 56 to the VKM 2, the hydraulic pump 10, the valve block 16, the hydraulic machine 34 and the clutch 52 and controls and controls them. For example, at the VKM 2 the speed and the hydromachine 34, the torque can be controlled.

The hybrid drive 1 in FIG. 1 is used in different operating states, which are controlled by the control unit 54. In a serial operating state, the hybrid drive 1 is operated as a serial hybrid with the clutch 52 being disconnected. The VKM 2 transmits a torque at a certain speed via the drive shaft 4 and the gear pair 6 on the first drive shaft 8, which drives the hydraulic pump 10. The mechanical energy of the VKM 2 is converted via the hydraulic pump 10 into hydraulic energy. The VKM 2 and the hydraulic pump 10 are so matched via the gear pair 6, both of which simultaneously reach their maximum speed. The hydraulic energy is stored either in the first position of the valve block 16 in the high-pressure accumulator 28 or with this, the hydraulic machine 34 is driven in the second position of the valve block 16. The hydraulic machine 34 then acts as a hydraulic motor 34 and drives on the drive shaft 40, the gear pair 42, the second drive shaft 44 and the differential gear 46, the output shafts 48 with the wheels 50 at.

The hydraulic machine 34 may also act as a hydraulic motor 34 in the third position of the valve block 16, as in the second. In this position, however, the hydromachine 34 can also be used as a hydraulic pump 34 by the braking energy into hydraulic energy at delays by, for example, braking the motor vehicle, the wheels 50, the output shafts 48, the differential gear 46, the second drive shaft 44 and the gear pair 42 transforms. This promotes pressure medium from the low pressure accumulator 24 via the first storage line 22, the low pressure line 38 and the low pressure port 36 to the high pressure accumulator 28 via the high pressure port 32, the high pressure line 30 and the second storage line 26. The serial operating state is used for example at low speeds and high loads, where this has a high efficiency.

If, for example, high speeds of the motor vehicle are required, the hybrid drive 1 is controlled by the control unit 54 in an operating state, in which this drives the motor vehicle via a purely mechanical drive train. In this case, the control unit 54 closes the clutch 52, whereby the first and second drive shaft 8, 44 are connected. At the same time, the hydraulic pump 10 and the hydraulic machine 34 are adjusted by the control unit 54 in such a way that the hydraulic pump 10 is pivoted to zero delivery volume and the hydraulic machine 34 to zero absorption volume and run along empty. Thus, the VKM 2 drives the wheels 50 directly via the gear pair 6, the two drive shafts 8, 44 and the wheel drive having the differential gear 46 and the output shafts 48, which is referred to as overdrive.

The hybrid drive 1 can also be used in a parallel operating state by the clutch 52 is closed as described above and in addition to the VKM 2, the hydraulic motor 34, the second drive shaft 44 drives. This is supplied either by the hydraulic pump 10 or by the memory arrangement of low and high pressure accumulator 24, 28 with pressure medium. In the latter case of the pressure medium supply, hybrid functions such as recuperation, boost, start-stop, engine operating point shift and operation without VKM 2 are made possible.

The various operating states of the hybrid drive 1 are set by the control unit 54 different and in such a way that the hybrid drive 1 has the optimum efficiency in any situation of use of the motor vehicle and at the same time takes into account the application request of a vehicle driver. Influencing variables for the control of the hybrid engine 1 by the control unit 54 are the respective maximum efficiencies of the VKM 2, the hydraulic pump 10 and the hydraulic machine 34. Further influencing factors are driving dynamics requirements of the driver, such as accelerator pedal and brake pedal position, the gradient of accelerator and brake pedal position and the vehicle speed and the state of charge of the accumulator assembly of low and high pressure accumulators 28, 24, such as accumulator pressure and accumulator temperature.

2 shows a hybrid drive 1 is shown in a schematic representation according to a second embodiment. The hydraulic motor 34 is in this case via a gear unit 58 in the form of two switchable gear pairs 60, 62 with the second Drive shaft 44 connected, wherein the circuit via a synchronization device 64 takes place. The gear pair 60, 62 each have a different translation, wherein the right in Figure 2 gear pair 62 corresponds to a 1st gear and the left gear pair 60 a second gear. As a result, on the one hand, a less powerful hydromotor 34 can be used and, on the other hand, the speed and torque range of the hydraulic motor 34 can be adapted more flexibly to the operational situation of the motor vehicle. Thus, two gears are selectable by the gear unit 58, which are actuated by the control unit 54 via the control line 56 which is connected to the synchronization device 64.

Based on the figure 3, the use of the hybrid motor 1 according to the second embodiment is explained in more detail in a traction diagram. The ordinate of the tensile force diagram forms a torque M in Nm and the abscissa of the diagram a speed v_Fzg km / h. The traction diagram shows a power hyperbola 66 (point line) which shows the maximum possible power of the VKM 2 (see Fig. 2), for example 110 kW, as a function of the speed and the torque. An upper line 68 (dashed line) in the tensile force diagram has a horizontal section and a section which runs along the power hyperbola 66. A second line 70 (dash-dot line) located below the line 66 also has a horizontal portion and a portion extending along the power hyperbola 68. The upper line 66 terminates at the point where the second line 70 abuts the power hyperbola 68. A third curved line 72 (dashed line) is drawn below the line 70 in the tension diagram.

When starting the motor vehicle, the hybrid engine 1 (see Fig. 2) is operated in the serial operating state with the 1st gear of the transmission unit 58 (see Fig. 2). The line 68 corresponds to the 1st gear and shows the maximum torque at a certain speed, which can make the hybrid engine 1. The acceleration is up to a speed (about 90 km / h) in this 1st gear, where the upper line 68 opens into the line 70. By the hybrid engine 1, each point between the upper line 68 and the abscissa is continuously attainable, the torque being adjusted via the hydraulic motor 34 (see Fig. 2). For example, starting from the speed zero, the maximum torque at the output is made available. When reaching the speed limit (about 90 km / h), the transmission unit 58 (see Fig. 2) is switched to the 2nd gear and the motor vehicle can with a maximum torque along the second line 70 to the maximum speed (about 230 km / h) are accelerated. Again, each operating point is operable between the line 70 and the abscissa. Before reaching the maximum speed of the hybrid drive 1 can also be controlled in the operating state where it drives the motor vehicle directly with the VKM 2 (marked by the line 72), since it has optimal efficiency at high speeds and low loads. This would be a 3rd gear.

3 shows that the hybrid drive 1 can be operated at arbitrary torques and speeds, and essentially by the maximum torque of the hydraulic machine 34 (see FIG. 2), the maximum power of the VKM 2 and the maximum speed of the engine Motor vehicle is limited. Thus, the hybrid drive is extremely flexible adaptable to energy-efficient operation.

The lines 66, 70, 72 of the tension diagram in Figure 3 correspond in principle to three gears of the hybrid engine 1, which are made possible by an extremely simple gear arrangement of the gear unit 58 (see Fig. 2) and a clutch 52. As a result, an elaborately constructed transmission, for example, a continuously variable transmission (CVT) transmission is no longer necessary.

FIG. 4 shows a hybrid engine 1 in a schematic illustration according to a third exemplary embodiment. The difference from the two other embodiments in FIGS. 1 and 2 is that the transmission between the hydraulic machine 34 and the second drive shaft 44 is designed as a planetary gear 74. This includes a planet gear carrier 76 connected to the hydromachine 34, on which a plurality of planetary gears 78 are interposed between a ring gear 82 and a sun gear 80. The ring gear 82 has a spur gear portion 84 which is connected to one at the second Drive shaft 44 arranged spur gear 86 forms a gear pair 88. The sun gear 80 is connected to a sun gear 89 at whose end a first brake disc 90 is provided which can be braked with brake shoes 92. These are actuated via the control unit 54 and the connected control line 56. In front of the brake disk 90 toward the sun gear 80, a second brake disk 94 is provided on the sun gear shaft 89, which can be braked with brake shoes 96 arranged on the ring gear 82. These are also controllable via the control line 56 to the control unit 54.

By the planetary gear 74, two gears are switchable as in the second embodiment of Figure 2, wherein this is done via a schleifendes switching by the brake shoes 92, 96 and thus when switching no interruption of traction of the hybrid drive 1 occurs. When braking the second brake disc 94, the sun gear 80 is non-positively connected to the ring gear 82 via the brake shoes 96. As a result, the planet gears 78 are fixed and the ring gear 82 is driven directly by the sun gear 80 from the hydraulic machine 34. Via the gear pair 88, the second drive shaft 44 is then rotated. This corresponds to a 1st gear. If the brake shoes 96 is released and at the same time the brake shoes 92 of the first brake disk 94 are activated, then there is a smooth transition to the second gear. In this case, the sun gear 80 is frictionally held by the brake shoes 92, which are fixed independently of the planetary gear 74 to the hybrid drive 1. Thus, the planet gears 78 on the sun gear 80 and the ring gear 82 can be unrolled, which drives the second drive shaft 44 via the gear pair 88.

In addition to the transmissions mentioned above in the exemplary embodiments, it is certainly also possible to use other types of transmissions in the hybrid engine 1 (see, for example, FIG.

Disclosed is a hybrid drive with a primary unit and a hydraulic machine, which are each connected to a drive shaft. The primary unit drives a hydraulic pump via the drive shaft, to which a hydraulic machine is hydraulically connected. The drive shafts are mechanically connectable.

Claims

claims

1. Hybrid drive with at least one primary unit (2) and a hydraulic machine (34), wherein these with a first drive shaft (44) and the primary unit (2) with a second drive shaft (8) are in operative connection, wherein on the second drive shaft (8) a hydraulic pump (10) is driven, which can be hydraulically connected to the hydraulic machine (34), wherein the first and second drive shaft (44, 8) are connectable via a coupling.

2. hybrid drive according to claim 1, wherein the hydraulic machine (34) via a transmission to the first drive shaft (44) is connected.

3. Hybrid drive according to claim 2, wherein the transmission of the hydraulic machine (34) is single-stage (42), multi-stage (58) or a planetary gear (74).

4. Hybrid drive according to one of the preceding claims, wherein the primary unit (2) is an internal combustion engine (VKM).

5. hybrid drive according to claim 4, wherein the VKM (2) via a motor gear (6) with the second drive shaft (8) is connected.

6. hybrid drive according to claim 5, wherein the motor gear (6) is single-stage.

7. Hybrid drive according to one of the preceding claims, with a valve block (16), via which a pressure port (12) of the hydraulic pump (10) with a high pressure accumulator (28) or a high pressure port (32) of the hydraulic machine (34) and with a suction port ( 18) with a low pressure accumulator (24) or with the low pressure port (36) of the hydraulic machine (34) and via which the high pressure accumulator (28) with the high pressure port (32) of the hydraulic machine (34) and the low pressure accumulator (24) with the low pressure port (36 ) of the hydraulic machine (34) is connectable.

8. hybrid drive according to claim 7, comprising a control device (54) for driving the VKM (2), the hydraulic machine (34), the hydraulic pump (10), the clutch (52) and the valve block (16) via control lines (56).

9. hybrid drive according to claim 8, wherein the control unit (54) controls a transmission unit (58) or a planetary gear (74).

10. Hybrid drive according to one of the preceding claims, wherein the hydraulic machine (34) and the hydraulic pump (10) are adjustable.

11. Hybrid drive according to one of the preceding claims, wherein the hydraulic machine (34) is to operate in 4-quadrant operation.

12. Hybrid drive according to one of the preceding claims, wherein the first drive shaft (44) with a differential gear (48) and a wheel drive arranged thereon (46, 48, 50) is in operative connection.