DE102015224805A1 - Hybrid powertrain with multiple drive components - Google Patents

Abstract

The invention relates to a drive train (1) for a motor vehicle having two internal combustion engines (2, 3) which can be coupled together for torque transmission to a hybridized transmission (4) with an electric machine (5) and a transmission (6) and to torque transmission on the one hand to a secondary engine (7) are designed and prepared, wherein the two internal combustion engines (2, 3) are designed and prepared for operation at mutually different speeds.

Description

The invention relates to a drive train for a motor vehicle, with two mutually torque torque coupled coupled internal combustion engines for torque transmission on the one hand to a (hybridized) hybrid module with an electric machine and a bspw. Downstream transmission and on the other hand for torque transmission to a secondary drive, such as an air compressor, pump , a loader, a endless drive means, a endless drive means tensioner, such as a belt or chain tensioner and / or a starter generator, are designed and prepared.

From the prior art, various systems for crankshaft separation, in which a part of the internal combustion engine is switched off according to demand, known. In this case, a switched-off internal combustion engine or an internal combustion engine part is then started and mechanically coupled again, if required by the power requirement. However, the re-coupling is technically very complicated, since a coupling element ratchet and / or backlash has to transfer the resulting shock moments that exceed the existing mean moments many times. In addition, the coupling element must ensure a defined, precise angular position with respect to the four working cycles of the internal combustion engine. Also with regard to the variable damping systems of such a system, many questions remain unanswered in the prior art.

Thus, the international patent publication WO 2011/160619 A1 an internal combustion engine comprising a plurality of subunits each having crankshaft parts arranged parallel to one another.

The prior art also discloses so-called range extenders or serial hybrids, in which an internal combustion engine is merely connected to a generator, which transmits its power to an electric battery, which then converts it into driving performance. The unfavorable overall efficiency of such systems is evident due to the many different energy conversions.

Also known from the prior art are so-called hybrid transmission or multi-speed range extender, in which the above problem of low efficiency is improved by a mechanical connection of the internal combustion engine with the driveline over several gears. However, these transmissions have the disadvantage that if the driver requests unpredictably much more power, a delay occurs when restarting, since the electric drive train is not sufficient for high performance.

The prior art also shows concepts with two internal combustion engines and an optionally hybrid power-mixing transmission. In this regard, the disclosures are DE 2013 102 219 11 A1 and DE 2013 102 219 12 A1 to lead. Here the problems of the crankshaft separation are solved on the transmission side, so that the two burners are no longer dependent on running synchronously.

The disadvantages of the prior art disclosed in these references are that many of these systems require an undesirable overhead in terms of auxiliary equipment. As auxiliary equipment here are, for example, air compressors, water pumps, oil pumps, brake booster, turbocharger and / or alternators. Since their function in a hybrid engine must be ensured even in a non-active combustion engine, the existing solutions in terms of space and complexity to be improved.

It is therefore the object of the present invention to overcome the disadvantages of the prior art, and in particular to disclose a technical device which is able to realize a hybrid drive, which allows both a reliable driving operation, and one at any Operating conditions adapted ancillary operation provides. Here, above all, the required space and the achievable operating flexibility should be emphasized.

This is inventively achieved in that the two internal combustion engines are designed and prepared for operation at mutually different speeds. This causes an independence of the two internal combustion engines of the drive train. Thus, a hybrid drive with high spontaneity can be realized because a pulse start option of a high-performance combustor can be used.

Advantageous embodiments are claimed in the subclaims and are explained in more detail below.

Thus, it is advantageous if the one / first internal combustion engine is an asymmetrically separated or separable part of the other / second internal combustion engine. This asymmetrical separation of the internal combustion engines can be realized, for example, by a larger driving drive and a smaller auxiliary drive. The fact that these drives are operable at mutually different speeds, they can each on the prevailing Operating conditions of the respective driven load to be adjusted.

As soon as the one / first internal combustion engine has a lower power capacity than the other / second internal combustion engine, this facilitates the asymmetry of the two drives. The flexibility of the powertrain is thus increased.

A further advantage is that both internal combustion engines are arranged in the same engine block or have the same engine housing / casting block for receiving combustion-force driven pistons. This increases the compactness of the powertrain and reduces its weight because two motors are integrated in one block. In this way, a space-and weight-optimized drive train can be realized. Furthermore, it is thus avoided that the vibrations caused by the different speeds lead to a relative friction of the motors. A robust engine seat of the drive unit with different internal combustion engines is the result.

An advantageous embodiment is also characterized by the fact that the weaker, first internal combustion engine, such as a secondary engine combustor, permanently / unsolvable or releasably coupled to the secondary engine and / or the more powerful, second internal combustion engine, such as a driving power burner, permanently / insoluble or else detachable, for example via a separating clutch, for example a K0 coupling, to which the hybrid module is coupled. This separation makes it possible to adapt both the secondary drive and the hybrid module to their optimum operating conditions. In this way, on the one hand, an efficiency-optimized application can be realized, on the other hand it can be avoided that the auxiliary drive and / or the hybrid module does not meet the performance requirements. The optional arrangement of coupling units between the internal combustion engines and the units driven by them enables the internal combustion engines to be operated in the speed range which is ideal for them. If switching off the motor does not make sense in the case of a lack of power requirement with regard to the operating efficiency, this can be replaced by decoupling.

If between two internal combustion engines a clutch, for example. A friction clutch, such as an impinged with short pulses impulse clutch, is present, the operation of the two internal combustion engines at different speeds can be realized in a structurally simple and at the same time efficient manner. Both a friction and a momentum coupling is considered a standard component and thus has a positive effect on logistical aspects of the device.

It is likewise advantageous if the one / first, power-reduced internal combustion engine is used for preheating a cooling fluid of the other / second internal combustion engine or the passenger compartment. Thus, synergy effects can be used. The smaller internal combustion engine has earlier reached its optimum operating temperature because of its size than the larger internal combustion engine. Therefore, it is suitable for preheating the cooling fluid of the larger internal combustion engine. This increases the overall efficiency.

A further advantageous embodiment is characterized in that the one / first internal combustion engine has a secondary engine combustor flywheel separate / component-separate from a second-internal combustion engine travel-drive combustor flywheel. The smoothness implied by a flywheel of an internal combustion engine is thus adapted to the two internal combustion engines in their respective optimal operating point. Not only in terms of their speed, but also in terms of their design and mass, the flywheels are therefore individually adapted to the prevailing operating conditions.

In this case, it is also advantageous if the auxiliary combustion engine flywheel is designed as a single-mass flywheel or as a dual-mass flywheel. Thus, depending on the existing components in the secondary engine optimal design of the flywheel can be achieved. The one-way flywheel has the advantage of reducing rotational nonuniformity of engine speed as well and further providing power output at the engine output. Furthermore, the one-mass flywheel has a low susceptibility to damage. The dual mass flywheel, on the other hand, almost completely isolates the driven components from the rotational nonuniformities resulting from the four power strokes. This reduction of the torsional vibrations is advantageous for the reduction of noise such as rattling, but also advantageous for improving the efficiency, for example in belt drives.

Once the one / first internal combustion engine is designed so that its idle speed is higher than the idle speed of the other / second internal combustion engine, or the maximum speed of the / a first internal combustion engine is lower / lower than that of the other / second internal combustion engine, resulting in the operating conditions customizable and optimizable (narrower) speed ranges of the secondary drive. Since the requirements for those speed spread, which is from the quotient of the idle speed to the maximum speed results in the ancillary units / the secondary engine require lower values than the hybrid module, the drive train according to the invention is advantageously set by means of those speed spreads. The low speed spread of the auxiliary drives makes it possible to operate the one / first internal combustion engine in an approximately constant speed range, which contributes to increasing their efficiency / consumption. Further, since the other / second internal combustion engine does not rely on the low speed spread, it is possible to satisfy a wide range of power requirements by a driver.

Another advantage results from the fact that the interconnection of the individual components is designed such that units of the secondary engine, which is coupled to a first internal combustion engine or can be coupled, independent of the speed of the other / second internal combustion engine are operable. All drive units integrated in the auxiliary drive are reliably operable in their speed range in this way.

Even if the hybrid module has an electric machine / an electric motor logically and geometrically at a transmission transition and can be decoupled via a main clutch of a / the Fahrantriebsverbrenner, there are advantages in terms of efficiency. Accordingly, in a corresponding stage of operation, the traction drive combustor may be operated without the electric machine / motor being active.

It is also advantageous if a rigid pulley with a large mass, such as waiving a pendulum clamp, is used in the secondary drive. The large inertia resulting from the large mass can compensate for irregularities / imbalances.

It is also advantageous if the power-capacitive smaller of the two internal combustion engines for driving the motor vehicle is unsuitable / incapable. This prevents a high quality and therefore costly design of the smaller drive unit.

Even if the one / first internal combustion engine is designed as a boxer engine and / or two-cylinder engine and / or V-arrangement or as a single-cylinder engine and the other / second internal combustion engine is designed as a multi-cylinder engine in a series or V arrangement, this has advantages. Both in terms of space, as well as in terms of their thermodynamic efficiency, such a combination of the drive units is advantageous.

In other words, it can be said that the device according to the invention discloses a hybrid drive which is characterized by a high degree of spontaneity due to a pulse start option of a high-performance combustor.

The hybrid drive according to the invention can be used by means of inexpensive secondary drive / auxiliary units due to their low speed spread. Here, the core idea is to provide an asymmetric separation of the internal combustion engine into a larger drive, e.g. a 3-cylinder in-line engine, and a smaller drive, for example, a 2-cylinder boxer engine, but which are located in the same engine block to make. The ancillaries are here only simple and are driven by the smaller engine, while the larger combustion engine is used for propulsion. The traction drive motor is started by engaging a clutch, for example a friction clutch, between the two internal combustion engines.

It follows that one of the two internal combustion engines of the drive train according to the invention is not mechanically usable as travel drive, but can be used via a mechanical friction clutch as a starting unit for the other internal combustion engine. It is advantageous if the smaller internal combustion engine alone drives the only secondary drive. Also, there is an advantage in that the smaller internal combustion engine is rigidly connected to an electric machine of similar power. In an alternative embodiment, the large starter generator is located near the starting clutch or around the starting clutch.

The start of the small combustion engine by means of a torsionally rigid connected electric machine. In particular, if the state of charge of a battery falls below a first charging limit value or if, for example, the driver's driving power requirement that can be recognized by the accelerator pedal exceeds a power limit value, this is useful. Both the smaller internal combustion engine and the secondary engine can be operated with a low rotational irregularity due to the torsionally connected large generator inertia and the controllability of the generator and they require little damping measures on the pulley. It can therefore be used a rigid or classic elastomer-damped pulley.

When the small combustion engine is running and driving power is not desired, the rigidly connected electric machine is operated as a generator in such a way that the small internal combustion engine operates at a low-consumption operating point. The generator operation in this case also depends on the power requirements of others Side drive units, in particular of the air conditioning compressor, as this can attract a significant performance. The generator operation in this case also depends on the state of charge of the coupled battery. If a second charging limit value is exceeded, the charging power is reduced or the smaller internal combustion engine is stopped. This stopping of the smaller internal combustion engine is prevented until a minimum temperature required for the exhaust gas purification system is reached or until an interior temperature desired by the driver is reached.

Thus, due to the electric drive of the traction drive (for example as a P2, P3 or P4 hybrid) which is activated according to the driver's request, the vehicle can also travel longer distances without the larger internal combustion engine having to be started due to decreasing state of charge.

The start of the larger internal combustion engine is done by engaging the engine starting clutch while the engine is running. This coupling is advantageously designed as a friction clutch and particularly advantageous as a self-opening clutch. The generator leaves the regenerative mode at this engine start and changes to a motor operation if necessary. The engagement of the starting clutch takes place at a time when the angular momentum L of the small motor including the generator is greater than the angular momentum _limit L _limit . The following mathematical relationship applies: (J _{ICE small} + J _generator ) · ω _{ICE small} > L _limit > 2 · J _{ICE large} · 25 rad / s

Here, J denotes the angular momentum of the respective components, ω the rotational speed and L _limit the angular momentum limit. In the manner described above it is ensured that a pulse start leads to a sufficiently high speed of the internal combustion engine.

The starting clutch is at the latest returned to an open state when the speed of the larger internal combustion engine exceeds a first speed limit, such as a limit of 3,000 rpm. This makes it possible to operate the smaller combustion engine more fuel efficient at lower speeds than at that speed limit. The starting clutch is also returned to an open state when the speed of the large burner falls below a further speed limit, for example. A speed limit of 800 U / min. In this way, it is possible to operate the secondary engine at higher speeds than that lower limit, which allows the driving of simpler units.

The operating speed of the smaller internal combustion engine is adjustable at an open starting clutch by a controller regardless of the speed of the larger internal combustion engine. This degree of freedom allows a demand-optimized operation of individual or selected secondary drive units. In particular, charge air compressors have an efficiency-optimized operating behavior when they are operated neither at low-speed, ie at low speeds, nor at high speeds, ie high speeds. Generators and / or pumps have a similar specific behavior.

The needs-based operation of the secondary engine by the smaller internal combustion engine here includes that at high tensile load, the speed of a belt-driven supercharger and thus the boost pressure is increased quickly, so that the larger combustion engine generates high torque at low speeds from its high cylinder charge. If necessary, the auxiliary drive was already in an optimal state of increased speed before increasing the tensile force requirement, so that the increase in the draft requirement can be implemented almost instantaneously, which allows sporty driving dynamics.

Furthermore, the needs-based operation of the secondary engine by the smaller internal combustion engine that at increased cooling power requirements, for example, caused by the air conditioning, the speed of the secondary engine is increased and thus a small refrigerant compressor draws a high refrigerant compression. Similarly, the needs-based operation of the secondary engine by the small internal combustion engine includes that at high vehicle speed, if sufficient air cooling is present, the speed of the secondary engine is reduced with the cooling water pump. At low vehicle speed, but high traction, for example, in mountain driving with high weight, when also a strong cooling is required, the speed of the by-drive can be increased with the cooling water pump.

For each member of the accessory drive a demand-driven control is possible. In particular, it is advantageous if the secondary drive and the accompanying components are operated with a reduced speed compared to a standard engine drive, in particular with a reduced maximum speed. The speed spread of 8 to 10, which is widespread in the prior art, is undershot by the secondary drive according to the invention. The speed spread according to the invention is between 2 and 6, preferably about 4.

In summary, the invention, the Teilmotorabkopplung in conjunction with a first electric motor as hybrid, for example. P2 hybrid, proposes on the gearbox side engine. In this case, the second sub-motor can be operated detached from the rotational speeds of the first sub-motor. In other words, it can be said that the rotational speed of one engine is operated independently of the rotational speed of the other engine depending on the required rotational speeds of the auxiliary machinery. It is also possible to completely switch off the one engine, so that the transmission is operated exclusively via the electric machine. For this purpose, a corresponding clutch, for example. A K0 clutch is provided. The smaller part engine can start the larger part engine. For this purpose, the smaller engine on a flywheel. This continues to fulfill the function of energy storage. The clutch between the two internal combustion engines is preferably a normally open clutch. Furthermore, the smaller engine can preheat the cooling water of the larger engine. The auxiliary drive units can be designed smaller than in conventional engines, since they can be designed for an optimal speed and do not have to accept large moments and irregularities of the large engine.

The invention will be explained in more detail by means of a figure.

It shows:

1 a schematic representation of the components of the drive train according to the invention.

The figure is merely schematic in nature and is for the sole purpose of understanding the invention.

1 shows a drive train 1 for a motor vehicle. In the drive train 1 is a first internal combustion engine 2 and a second internal combustion engine 3 integrated. The two internal combustion engines 2 . 3 are combined in one unit. The second internal combustion engine 3 This is larger / more powerful than the first internal combustion engine 2 executed. The second internal combustion engine 3 is via a torsion damping system 11 , which can be shortened referred to as damping system and as a dual mass flywheel is realized, to a hybridized transmission 4 coupled. This gear 4 includes, inter alia, an electric machine 5 and a multiple-speed translation part 6 , the electric machine 5 can be upstream or downstream. The gear 4 drives the wheels of the vehicle via cardan shafts or side shafts. The first internal combustion engine 2 is on a side drive 7 connected. In the secondary drive 7 For example, air conditioning compressors, pumps, turbochargers, belt tensioners and / or an alternator are integrated.

The basic structure of a hybrid module is the German Offenlegungsschrift DE 10 2014 212 799 A1 refer to. The disclosure of that document is considered to be incorporated herein. As a hybrid module, a device is fundamentally considered which has at least one separating clutch in order to couple the internal combustion engine on the transmission side. The electric machine is also coupled to the hydraulic module and permanently connected to the transmission side.

In an alternative embodiment, the translation part is 6 arranged outside of a hybrid module.

Between the first internal combustion engine 2 and the second internal combustion engine 3 is a clutch 8th arranged. The coupling 8th is suitable for the second internal combustion engine 3 by means of the first internal combustion engine 2 to start. Furthermore, it leaves a decoupled operation of the two internal combustion engines 2 . 3 to. The first internal combustion engine 2 is to a starter generator 9 coupled.

As part of the hybridized transmission 4 is a decoupled hybrid head can be used. It is also the use of full or partial hybrids conceivable. The hybrid head is characterized by a reduction in fuel consumption, while increasing the driving dynamics. Both a support, as well as a replacement of the second internal combustion engine 3 by the electric motor / the electric machine 5 is possible.

With the reference number 10 the schematically indicated engine block is shown. The engine block 10 includes both the first internal combustion engine 2 as well as the second internal combustion engine 3 , It is characterized by a high degree of compactness.

The first internal combustion engine 2 is also coupled with a starter generator. Such is a starting of the first internal combustion engine 2 possible via the generator integrated in the secondary drive. The second internal combustion engine 3 is not necessarily equipped with a starter generator. You can over the clutch 8th and thus on the first internal combustion engine 2 to be started.

LIST OF REFERENCE NUMBERS

1

 powertrain

2

 first internal combustion engine

3

 second internal combustion engine

4

 (hybridized) transmission

5

 electric machine

6

 translation part

7

 Accessory drive

8th

 clutch

9

 starter generator

10

 block

11

 (Torsional) damping system

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2011/160619 A1 [0003]
• DE 201310221911 A1 [0006]
• DE 201310221912 A1 [0006]
• DE 102014212799 A1 [0044]

Claims (10)

Powertrain ( 1 ) for a motor vehicle with two mutually torque-coupled coupled internal combustion engines ( 2 . 3 ) which, for torque transmission, on the one hand to a hybridized transmission ( 4 ) with an electric machine ( 5 ) and a transmission ( 6 ) and, on the other hand, for transmitting torque to an auxiliary drive ( 7 ) are designed and prepared, characterized in that the two internal combustion engines ( 2 . 3 ) are designed and prepared for operation at mutually different speeds. Powertrain ( 1 ) according to claim 1, characterized in that the one combustion engine ( 2 ) an asymmetrically separated or separable part of the other internal combustion engine ( 3 ). Powertrain ( 1 ) according to one of claims 1 to 2, characterized in that the one internal combustion engine ( 2 ) has a lower power capacity than the other internal combustion engine ( 3 ) owns. Powertrain ( 1 ) according to one of claims 1 to 3, characterized in that both internal combustion engines ( 2 . 3 ) the same engine block ( 10 ). Powertrain ( 1 ) according to one of claims 2 to 4, characterized in that the less powerful, first internal combustion engine ( 2 ) permanently or detachably with the secondary drive ( 7 ) is coupled and / or the more powerful, second internal combustion engine ( 3 ) permanently or detachably with the hybridized transmission ( 4 ) is coupled. Powertrain ( 1 ) according to one of claims 1 to 5, characterized in that between the two internal combustion engines ( 2 . 3 ) a coupling ( 8th ) is available. Powertrain ( 1 ) according to one of claims 2 to 6, characterized in that the one internal combustion engine ( 2 ) for preheating a cooling fluid of the other internal combustion engine ( 3 ) is designed and / or used. Powertrain ( 1 ) according to one of claims 2 to 7, characterized in that the one internal combustion engine ( 2 ) has an auxiliary internal combustion engine flywheel, which of a traction drive flywheel of the other internal combustion engine ( 3 ) is designed separately. Powertrain ( 1 ) according to claim 8, characterized in that the auxiliary combustion engine flywheel is designed as a single flywheel or as a dual mass flywheel. Powertrain ( 1 ) according to one of claims 2 to 9, characterized in that the one internal combustion engine ( 2 ) is designed so that its idle speed is higher than the idle speed of the other internal combustion engine ( 3 ) and the maximum speed of an internal combustion engine ( 2 ) is lower than that of the other internal combustion engine ( 3 ).

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