DE2353724B2 - Hybrid drive with two drive machines working on the output shaft via a power split gear - Google Patents

Description

The invention relates to a hybrid drive t two via a power split transmission : Drive machines working on the output shaft, one of which is at a fixed speed a gyro memory is assigned to compensate for power peaks, while the second The drive machine is an electric machine, the speed of which in the power split transmission corresponds to the speed of the first drive machine is added or subtracted from this.

Such a hybrid drive (DT-OS 2153 961) is particularly suitable for an unsteady mode of operation, e.g. B. in motor vehicles, which is known in particular are subject to "stop and go" traffic to a large extent in metropolitan areas Way there are also applications for electric roads and / or rail vehicles with changing Drive loads as a result of acceleration or deceleration (e.g. in local high-speed traffic). The usage for stationary systems, especially with changing loads, is also provided.

The transient mode of operation not only has a disadvantageous effect on conventional drives Overall efficiency, but also brings significant problems in terms of noise and Pollutant emission with it.

This is usually a drive for maximum loads is designed, result when the peak performance exceeds the basic performance many times over, Disadvantage ·. *, E.g. B. unfavorable consumption and emission ratios nisse in the lower partial load range for heat engines and a high expenditure for power control devices.

Attempts have already been made to counter these conditions with a hybrid drive, in which one electric drive machine was combined with a different type of drive machine.

DT-OS 21 53 961 describes a hybrid drive of the type mentioned at the beginning, in which the output shafts of an electric machine and an internal combustion engine each connected to a differential gear serving as a power split gear whose output shaft is the sum of the individual power to the drive wheels of a vehicle gives away. The output shaft of the first drive machine is also via a transmission gear with a connected to the flywheel acting as a gyro memory. Furthermore, one is assigned to the two drive machines, common control device provided. Each output shaft of a prime mover is also included provided with a brake so that each drive machine may also be effective on its own can.

In principle, the two drive machines, which can have different control characteristics, serve the coverage of the basic performance, while the gyro storage due to its favorable power-to-weight ratio and its power multiplication ability is able to cover power peaks. It is thus possible to use relatively small, but roughly the same size drive machines.

While the conventional motor vehicle drive generally consists of a very small one, only for starting or for the electrical power supply of the auxiliary units serving electrical machine and all power peaks covering heat engine exists, which is only used to reduce the degree of irregularity a flywheel is assigned, there is the hybrid drive described in DT-OS 21 53 961 from a much smaller heat engine and an electric machine of about the same size, whereby both have to cover a base load in terms of performance, while the peaks through the assigned gyro memory can be collected.

If you want a hybrid drive of this type that makes use of the gyro memory, a high dynamic Performance, e.g. B. to start up, so requires This includes the installation of a relatively large electric machine, i.e. roughly equivalent to the heat engine.

However, it must be taken into account that such an electric machine is many times larger in size It must be used as the starter and alternator of a conventional drive. Apart from the fact that one relatively large electrical machine also a relatively large - and therefore heavy - electrical storage device requires, there is a further disadvantage in this hybrid version that there is regenerative braking the recoverable kinetic energy is distributed roughly in equal parts to the electric machine and the electric storage unit on the one hand and on the Gyrospeicb ^ r on the other hand. The energy recovery through the various however, electrical equipment is significant because of the multiple conversion of the form of energy less favorable than with the gyro memory. As a result is the resulting overall degree of recovery and thus also the energy consumption are still unsatisfactory. Also the production costs for the electrical part are due to the unfavorable power to weight ratio and Weight price higher than for the other branch of the hybrid drive.

In addition, there is the fact that a relatively large electric machine compared to conventional starters high operating voltage, e.g. 144 volts versus 12 or 24 volts, and associated additional Requires safety devices and another low-voltage electrical system.

Thus, the inherent principle advantage of the hybrid drive is largely inefficient Factors impaired or almost canceled.

If you want to improve such a hybrid drive in terms of its economy, then it comes It is essential to make the electrical part as small as possible, but as large as necessary.

When considering the torque equilibrium at the power-split transmission, it emerges that the drive torque (Ma) is equal to the product of the torque (Me) of the electric machine and the reduction ratio (ie) assigned to it, if η is initially neglected the moment of inertia (Qe) of the electric machine:

Vi, = ,, ■ VJ,

If one strives for a hybrid drive with a small electric machine, this requires a large reduction ratio ie. However, there are two fundamental limits to this. When accelerating from standstill of the output shaft, the speeds of the shafts of the drive machines connected to the power-split gearbox are oppositely equal, and because of the reduction ie the speed of the electric machine is greater by the factor //: higher than the speed of the other drive machine.

However, the speed of the electric machine is structurally limited. On the one hand, because of the given power of the electric machine, its torque Me and thus the starting torque Ma would be very small at very high speeds of the electric machine. On the other hand, the moment of inertia Qe of the electric machine during acceleration cannot be neglected, since it is multiplied by the square of the reduction ratio k and is included in the consideration of the moment. The relationship is thus:

where h is the rotational acceleration of the electric machine

This consideration shows that a hybrid drive with a very small electric machine in the known design would have significant deficiencies in acceleration performance.

The invention is therefore based on the object of improving the known hybrid drive so that it Capable of doing this even with an electric machine with a low output without significant additional effort is to meet the desired operating conditions.

Starting from a hybrid drive of the type mentioned at the outset, this object is achieved according to the invention solved in that the electrical machine is dimensioned significantly smaller than in terms of its performance the first prime mover and the gyro memory that between the electric machine and the output shaft the first drive machine, a reduction gear is provided, and that between the electric machine and the power-split transmission, a disconnect clutch that can be slidably actuated at least when starting up is arranged.

The reduction ratio between the electric machine and the other machine can here be chosen relatively large, since the speed limitation of the electric machine by the installation of the Separating clutch has become obsolete.

During coupling, the electrical torque (e · Me) and the moment of inertia add up

because the electric machine initially during the acceleration of the vehicle, i. H. during coupling, z. B. from standstill is accelerated to a negative speed. The output torque thus results in:

M ₄ = U ₁ ■ M ₁ ) + Ui · (->,.; ■ »,,)

The transmission ratio (ie) has a positive effect on Ma in both terms and can therefore be chosen to be large. This is advantageously chosen so that the moment of inertia of the electric machine reduced to the circumference of the drive wheels of the vehicle is approximately of the same order of magnitude as the vehicle mass.

The introduction of a starting and separating clutch between the electric machine and the power Splitting gear makes it possible to use a relatively small electric machine in the hybrid drive to be provided. If the power of the electric machine is actually low, the desired high * dynamic drive power achieved.

The possibility of using a much smaller elec tromasehine leads to lower expansion and maintenance costs including the costs for the Electric storage. At the same time, the weight savings of a larger payload come with the Hybrid-An drove the equipped vehicle. Ultimately, there is a higher energy recovery rate efficiency. Overall, an extremely favorable overall economic efficiency can be achieved.

Theoretically, the separating clutch could also be at the output of the power split transmission be fine, but it would have to have the entire drive there

transmission and not just the much lower power of the electric machine. The disconnect clutch can be designed as a mechanical, hydraulic or electrical coupling and should preferably be electrically operated.

According to one embodiment of the invention, it is advantageous if the first drive machine with regard to their control behavior is slower and more limited in terms of the speed and load range to be controlled is than the electric machine.

The first drive machine assigned to the gyro memory, e.g. B. a heat engine at a vehicle the component for a long range as well as for the essentially stationary States, while the more easily controllable electric machine, the z. B. be assigned to an electrical storage device can, with the gyro memory enables the handling of the transient operating mode

Since a heat engine in the hybrid drive according to the invention has essentially little acceleration and can be driven in favorable areas of its map, it offers an excellent Combustion efficiency, so that the energy consumption is low and exhaust gases with an extremely form a low proportion of pollutants.

In the hybrid drive according to the invention, at least the drive machines, the gyro memory, the power split gear and the reduction gear with the separating clutch in one Block summarized

The hybrid drive according to the invention is also particularly suitable for vehicles in which No emissions at all should occur! In this case it is advantageous if all prime movers except for the gyro memory there are electric machines.

These can be fed from the grid as well as from suitable electrical storage systems. It results This has the further advantage that the battery and / or the network have lower power demands are exposed.

Here, too, the electrical machines are of different sizes, the larger of which is assigned to the gyro memory and the smaller one is provided with a separating clutch via a reduction gear The above-mentioned principles can also be supported by the drive machine assigned to the gyro memory or be more controllable than the others and essentially take on the task of continuous operation, where it only requires a simple, inexpensive control device

Another advantageous embodiment of the invention is that on the shaft of the gyro memory an eddy current brake is arranged An eddy current brake can because of the reduction gear be dimensioned relatively small between the gyro memory and the associated drive machine. You can z. B. used as a retarder when driving downhill with a vehicle provided with the hybrid drive will.

Exemplary embodiments are explained in more detail below with reference to the drawing

F i g. 1 is a block diagram of a hybrid drive according to the invention for driving a vehicle,

F i g. 2 a modified version of a hybrid drive,

3 shows an embodiment of a hybrid vehicle drive,

F i g. 4 another embodiment of a hybrid vehicle drive,

F i g. 5 is a plan view of a vehicle equipped with a hybrid drive;
F i g. 6 a detail and

F i g. 7 is a block diagram of a hybrid drive for two electric drive machines.

In the drawing, the same parts are provided with the same reference numbers.

F i g. 1 shows the hybrid drive according to the invention

ίο as a drive for a vehicle. A first prime mover 4 acts via a shaft 5 on a power split transmission 3 to which an output shaft 6 is connected is. This drives drive wheels 7 via a vehicle differential 18. The power split transmission can be designed as a differential gear, in particular as a planetary gear or the like. On the Power split transmission 3 acts as a second drive machine, an electric machine 1 with the interposition a reduction gear 24 and a separating clutch 25 with output shaft 26. The Electric machine 1 draws its energy from an electric storage unit 2.

Due to the reduction gear 24, it is possible, the first drive machine 4, which is either Heat engine or can be designed as a further electric machine, in terms of their performance and Design energy to be significantly greater than that of the electric machine 1. The first drive machine 4 is expedient slower in terms of their control behavior or in terms of the speed and load range to be regulated more narrowly limited than the electric machine 1 and thus suitably an essentially constant one To carry the basic load of the drive.

As a further drive means, in particular to address the disadvantages described at the outset in the case of discontinuous Avoid operation (too high positive and negative power peaks in the electrical part) and around to operate the first drive machine 4 as continuously as possible even in this operating mode, d. H. with only little and / or slow change of the actuator, z. B. a throttle valve for torque and speed, a gyro memory (flywheel) 8 is provided, which has a brake 16, advantageously one Eddy current brake (F i g. 6) can be assigned

and via a reduction gear 9 with the Output shaft 5 of the first drive machine 4 is in connection

The overall drive thus consists of three different types of components: large first

prime mover, small electric machine and gyro storage.

In order to adapt to different driving resistances, a torque converter 11 is located in the output shaft 6 intended. In order to make the hybrid drive so that it can be decoupled from the drive wheels 7, a clutch 10 is required provided in the output shaft 6. Between the power split transmission 3 and the torque converter 11 is e.g. a parking brake to lock the vehicle in the output shaft 6 12 installed between the first drive machine 4 and the power split transmission 3 is also a parking brake 14 is arranged which only allows the electric machine 1, for. B. with emission-free Driving in metropolitan areas. A controller for the entire hybrid drive is designated by 13.

A sensor 19 acts on the output shaft 6, the speed changes, d. H. Accelerations or decelerations the output shaft 6 via a sensor line

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JO enters a (preferably electronic) control device 17 for the electric machine 1. These Control device 17 has an adjusting device 21, for example a shift lever, for preselecting certain Driving characteristics.

By known, suitable but not shown devices of the power transmission, it is possible to the Electric storage 2 when the vehicle is stationary, especially at night, or when the track-bound operation of the Vehicle, for example on guardrails, from the outside z. B. to charge from the electrical network, as far as that The vehicle is not only fed from the grid anyway, i.e. without an electric storage device. He's with a den Battery charge status indicating sensor 22 connected via a line 23 also with the Control device 17 can be connected. With the help of the regulation by the sensors 19 and 22 for example, an unnecessary upshift is prevented or the preselected operating condition is modified will. In addition, the sensor 22 prevents the battery from being overcharged.

The operation of the in F i g. The hybrid drive of a vehicle shown in FIG. 1 is based on the example of starting described:

First of all, the vehicle is at a standstill, with the separating clutch 25 open, the first drive machine 4 z. B. runs at medium speed and drives the output shaft 26 in the opposite direction of rotation via the power split transmission 3. The gyro store 8 rotates at a corresponding, higher constant speed. By gradually engaging the separating clutch 25, the electric machine 1 is switched on and initially accelerated in a negative direction of rotation. In doing so, influenced by the controllers 13 and 17, it emits both an electrical moment and a moment due to the inertia of its mass.

Since the driving torque of the first drive machine 4 is not only very slow changes or an imbalance of the moments at the inputs and outputs of the power branching transmission 3, as the torque on the shaft 5 ht initially too small, the speed of this input and therefore of the Gyrospeichers 8 therefore begins to diminish and "by itself" (inertia of the gyromass) creates a supporting moment at this entrance.

With a gradual decrease in speed, the gyro memory then transfers its kinetic energy to the Vehicle drive from. After the coupling process has been completed, the negative speed of the changes Electric machine 1, then goes through its zero value (transition from generator - to engine operation) and is increased by means of the controller 13 as required by the desired driving speed. The for the The electrical energy required for motor operation of the electrical machine 1 is taken from the electrical storage unit 2. Deceleration processes run in the opposite direction, with the kinetic energy being a smaller part with conversion losses as electrical energy in the electrical storage unit 2 and for the most part almost Is collected lossless as kinetic energy in the gyro memory 8.

To change the speed range, e.g. B. when accelerating or driving slowly of inclines, the torque converter 11 is used.

By means of a corresponding circuit and actuation of the controller 13, the energy from the electrical storage unit 2 «« • ■ Most electrical machines 1 also for starting the first drive machine 4 can be used if it is designed as an internal combustion engine. Furthermore, the Electric storage 2, or a part of it, used to feed the electrical system of the motor vehicle will.

The controller 13 can be designed so that with the power division between the electric machine and the first, which can be selected in wide operating ranges Drive machine 4, especially if this one

ίο is the heat engine, whose operating status is as possible be controlled so that the resulting heat losses, z. B. cooling water and exhaust gases, the Cover the heat demand of the vehicle heating system. So when the vehicle is stationary, the heat engine can at the same time

is the function of battery charging and auxiliary heating fulfill. This means that the additional unit that is often installed as a parking heater today is no longer necessary.

F i g. FIG. 2 shows an embodiment equivalent to FIG. Provided that the reduction gear 9 and 24 of the gyro memory 8 and the electric machine 1 are about the same, it is also possible the power split transmission 3 directly to the shafts 27 and 28 of the gyro memory 8 and the To connect electric machine 1 and the already existing reduction gear 9 as a reduction gear to use the drive machine 4, so that its output power from the output shaft 5 via the Transmission gear 9 is transferred to the shaft 27 and introduced into the power split gear 3 will.

As already mentioned, the output shaft 27 of the Gyro memory 8 expediently assigned a brake 16 designed as an eddy current brake, which z. B. when the gyro memory 8 runs out to absorb energy. Like F i g. 6 shows the rotor of this Eddy current brake can also be designed as part of the gyro memory 8 or be permanently connected to it.

A practical embodiment of a hybrid drive on a motor vehicle, FIG. 3, the drive wheels 7 as either rear or front Wheels of a motor vehicle can be understood. The first drive machine 4 drives here by means of their Output shaft 5, which the energy of the gyro memory 8 via a reduction gear, not shown is switched on, the sun gear 29 of the power split gear 3 designed as a planetary gear, on whose web 30 connected to the output shaft 6 planet gears 31 are mounted, which with a Face gear 32 are in engagement, which in turn over the reduction gear 24, designed in this case as a bevel gear, and the separating clutch 25 is connected to the electric machine 1. This electric machine 1 is in energy exchange with the Electric storage 2.

The sensor 1 connected to the output shaft 6 « is connected to a control device 44 via a second output 43, which is based on the non-driven wheels 45 arranged vehicle brakes 46 acts otherwise corresponds to the wide Structure of this exemplary embodiment corresponds to that of FIGS. 1 and 2.

The hybrid drive can only be electric! Drive machines and a connected gyro memory exist. The electric drive machine!

can draw their energy from the energy store 2 or directly from a line network.

If, on the other hand, the first drive machine 4 is designed as a heat engine, this can al

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Internal combustion engine or as a steam engine or turbo engine.

F i g. 5 shows a top view of a motor vehicle 33, the hybrid drive 34 according to the invention being advantageous is arranged as a front-wheel drive.

By arranging the hybrid drive as a front-wheel drive of a vehicle, one achieves a cheaper transmission, especially the braking torque and is able to use all gears, in particular also the vehicle differential, to be accommodated in a single load-bearing transmission block. This embodiment the block construction is shown in FIG. 4. Here are the power split transmission 3, the torque converter II in the form of a gearbox and the vehicle differential 18, as well as the prime movers 1, 4 and the gyro memory 8 combined as a self-supporting block 35.

The electric machine 1, which is fed by the electric store 2, drives in via the separating clutch 25 Sun gear 36 of the power split gear 3, designed as a planetary gear.

On the output shaft 26 of the electric machine 1, the web 37 of the planetary gear is rotatably mounted and carries the planet gears 38 meshing with the sun gear 36. Each of these planet gears 38 is rigid with it connected to a coaxial planetary gear 39 which in turn meshes with a sun gear 40 which connected to the output shaft 5 of the first drive machine 4 and coaxially aligned with the sun gear 36 is arranged The transmission or reduction ratios between the two sun gear-planet gear pairs 36, 38 on the one hand and 39, 40 on the other hand are chosen so that they correspond to one another. Of the Gyro memory 8 is connected to output shaft 5 via reduction gear 9.

The web 37 is designed as a spur gear and is connected to a much smaller gear 41 of the Gearbox 11 in engagement, which is designed as a conventional gearshift gearbox and the Stegrad 42 of the vehicle differential 18 drives.

The hybrid drive shown in FIG. 7 has two electric drive machines 1 and 4 and is suitable to drive network-dependent vehicles. He

ίο also enables in particular with unsteady operation here an improvement in the overall efficiency and a significant reduction in the power peaks in the Network.

Those with the F i g. 1 to 6 functionally identical parts are provided with the same reference numerals.

The main advantage of the hybrid drive according to the invention consists in both types of embodiment in that the prime movers only need to be designed for an average load and not as usual for a peak load. The required peak loads are through the gyro store mechanically controlled by the electric machine 1 via the power split transmission 3 covered. The gyro memory 8 in particular also enables the use of small drive machines, which is particularly useful in vehicle construction The gyro memory is advantageously dimensioned so that its kinetic energy is in the The order of magnitude of the kinetic energy of the vehicle is approximately at maximum speed, and that the the first drive machine 4 assigned to the gyro memory 8 is dimensioned in terms of its power so that it covers the stationary driving resistances.

See S sheet drawings

Claims (8)

Patent address: 1. Hybrid drive with two via a power split transmission on the output shaft working prime movers, one of which Drive machine with a fixed speed relationship, a gyro memory to compensate for power peaks is assigned, while the second drive machine is an EJektromaschine whose speed im Power split transmission added to the speed of the first drive machine or from this is subtracted, characterized in that the electric machine (1) with regard to its Power is dimensioned much smaller than the first drive machine (4) and the gyro memory (8), that between the electric machine (1) and the output shaft (5) of the first drive machine (4) a reduction gear (24; 9) is provided, and that between the electric machine (1) and the Power-split transmission (3) has a disconnecting clutch that can be operated slidingly at least when starting up (2S) is arranged. 2. Hybrid drive according to claim 1, characterized in that the first drive machine (4) is also an electric machine. 3. Hybrid drive according to claim 1 or 2, characterized in that the first drive machine (4) sluggish in terms of their control behavior and in terms of the speed and speed to be regulated Load range is more narrowly limited than the electric machine (1). 4. Hybrid drive according to one of claims 1 to 3, characterized in that between the Power split transmission (3) and the output shaft (6) a torque converter (11) is provided is. 5. Hybrid drive according to one of claims 1 to 4 for a vehicle, characterized in that the Gyro storage (8) is dimensioned so that its kinetic energy is of the order of magnitude kinetic energy of the vehicle is approximately at maximum speed. 6. Hybrid drive according to one of claims 1 and 3 to 5 with a heat engine as the first Drive machine, characterized in that the electric machine (1) with its control device as Starter device is designed for the heat engine. 7. Hybrid drive according to one of claims 1 to so 6, characterized in that an eddy current brake is installed on the shaft of the gyro storage drive (8) (16) is arranged. 8. Hybrid drive according to one of claims 1 to 7, characterized in that at least the drive machines (1, 4) of the gyro memory (8), the Power split gear (3) and the reduction gear (9, 24) with separating clutch (25) in are combined in a block. ho