Drive system with a drive engine, an electrical machine and a battery

The invention relates to a drive system with a drive motor, specifically an internal combustion engine A motor vehicle and an electric machine.

Drive systems of motor vehicles with internal combustion engine Are conventionally two Electrical machines. An electric Machine serves as generator for power supply (Alternator), another for starting the internal combustion engine (Starter).

Further, a motor vehicle has a battery which The function of a chemical store of the Generator. In the Battery stored energy is used to start the battery Motor vehicle and for operating electrical loads Is used.

Electrical machinery, internal combustion engine And battery will be for the particular application Matched. The battery is used in drive systems Conventional vehicles To provide the power required for internal combustion engines High starting power. Furthermore, In particular in the case of a non-driven alternator, Electrical energy for electrical consumers provide.

Conventionally, in the motor vehicle A lead / sulfuric acid accumulator is used as a battery (See Robert Bosch GmbH, "Automotive Engineering Handbuch ", VDI-Verlag, Dusseldorf 1991, p.763 f.). This is characterized by high cycle number and high Reliability and at the same time is cost-effective. The Known motor vehicle drive systems Lead / sulfuric acid accumulator have the disadvantage, however, That it is limited in its power and energy density are.

From the publication L. Küng et al., Hybrid III, Concepts for the electric system of a hybrid Passenger car, Symp Proc 11 th Int Vehicle Symp, 1992, according to which the concept of Claim 1 has been formed The invention relates to a hybrid vehicle in which Drive battery at an elevated voltage level Of an intermediate circuit. At a very low power requirement, this works Vehicle pure electric, at slightly higher Performance requirement in a combustion engine Or electrical cycle operation, and At high power requirement combustion engine. For acceleration support in the Cycle operation is a mechanical flywheel Provided.

The present invention is based on the Technical problem, a simple Built hybrid vehicle with good Performance.

It achieves this with a drive system according to Claim 1.

The drive system is installed in a vehicle, In particular in a motor vehicle. As (Main) drive unit, it has a motor, in particular A combustion engine. The combustion engine is When driving the vehicle in time By an electrical machine. It can Also several motors and / or several electrical Machinery. The electric machine (s) Will be from one or more short-term batteries . These are compared to the batteries Conventional drive systems of motor vehicles Highly load-bearing and have a short discharge duration on. For this reason, the short-time battery can Powered electric machine Additional, can only be sustained over a short period of time Drive (short-term acceleration, "Boost").

The drive system according to the invention provides Ie a high-performance memory for short-term additional Acceleration reserves.

Such a drive system can be arranged opposite Conventional systems With the same fuel consumption To reduce fuel consumption. The reason is the following:

Average trips with motor vehicles Are characterized in that they are long lasting Phases of lower demand for the drive power With short-lasting phases of higher requirements alternate. For example, a short Acceleration phase after start a long phase Of driving at higher constant speed, Followed by a brief acceleration phase Overtaking, etc.

With conventional drive systems The internal combustion engine alone for the drive. This Must therefore be lesser in the long-lasting phases Requirement to drive a low, and In the short-term phases of higher requirements To the drive output a high torque. To achieve independence from the motor size, Refer to the torque supplied by the engine The stroke volume of the engine (so - called effective pressure or Effective medium pressure). The engine is thus relatively long In the range of lower effective average pressures (ie Teillast), and relatively short in the range of higher effective (Ie, at or near full load).

Effective medium pressure and speed set the Operating point of the motor. The operating point is affected Substantial noise, exhaust emission, stress And specific fuel consumption of the Motor.

The specific fuel consumption (ie the Fuel consumption related to engine power) Of the engine is essentially determined by the effective medium pressure, And only slightly influenced by the rotational speed. At lower effective mean pressures the specific Fuel consumption is generally relatively high, While at higher effective mean pressures Is generally relatively low

The specific fuel consumption of the engine Its efficiency is inversely proportional. The engine of conventional drive systems As a result of which, over long periods of time, Operated over short periods at high efficiency. This results in an unfavorable overall efficiency And a high fuel consumption.

In the drive system according to the invention, The motor is advantageously designed to be smaller, ie, That it is already in the phases of lower power requirement At or near full load, ie in energy More effective range of higher effective medium pressures becomes.

In phases of higher performance requirements Then provides the electrical machine, and not the motor For the additional drive ( "boost"). The short-time battery Is designed such that its (short) discharge duration Is greater than the duration of a phase of a higher power requirement. Even if in phases higher Power requirement the system motor - electrical Machine has a lower efficiency than A motor which alone is responsible for the drive An increase in the overall efficiency. The reason Is, as explained above, the phases of higher power requirement Are shorter than the phases Performance requirement.

The drive system according to the invention is used As a result of which time periods are high and high Short periods with low efficiency. This results in a higher overall efficiency. The drive system according to the invention thus increases A reduction in fuel consumption and thus Also to a reduction in pollutant emissions.

In addition, the drive system according to the invention has The advantage of small size, low Weight and low cost. The reason lies on the one hand In the smaller interpretation of the Combustion engine, and secondly, in use A high-capacity battery with a short discharge duration (Short-time battery). In principle, the use would also be A battery with the same high load Long discharge time, ie correspondingly higher capacity (And thus stored energy). batteries But are technically and technically advanced The more complex the higher energy weight (in Wh / kg) And energy volume (in Wh / l). This would happen when using A heavy duty battery with a long battery life Discharge time compared to a short-time battery Larger size and weight and / or increased Higher costs.

Except a heavy duty battery In principle also the use of a low load-bearing Battery conceivable. Since, however, Batteries Power weight (in W / kg) and power volume (In W / I) are lower, the same as for the above The fuel-efficient effect required The electric machine only with large and Heavy, light-weight batteries. This would result in using a low load Battery to a large and heavy total system Resulting in increased fuel consumption As a result. The system according to the invention With a high-voltage (short-time) battery The advantage of small size and small size Weight and therefore also lower fuel consumption.

The drive system according to the invention has Thus summarizing the advantages<ul><li>low weight</li><li>small size</li><li>low cost</li><li>low fuel consumption</li><li>Low pollutant emission.</li></ul>

It will thus be a light, compact and inexpensive Drive system is provided which is arranged opposite Conventional drive systems Maximum fuel consumption is reduced and Thus a step on the way to the consumption-optimized motor vehicle

The drive system according to the invention allows Also, a higher maximum power Conventional drive systems with the same fuel consumption to provide.

The engine is a reciprocating piston engine With internal combustion, like an ottooder Diesel engine. Also conceivable is another internal combustion engine, Such as a reciprocating piston engine with external Combustion (sterling engine) or a circular piston engine (Eg Wankel motor).

The electric machine is any type of machine For rotational or translational movements, Which as an electric motor driving on the vehicle Can be effective. It can be used as a synchronous, asynchronous or Reluctance machine, in particular also in sectoral construction Respectively.

The electric machine can be used for driving Of the vehicle directly or indirectly to the engine be. For example, a part of the machine, In particular the rotor, with the drive train of the motor Non - rotatably coupled, with an additional Torque To drive the motor. Moreover, the electrical Machine indirectly via one or more elements, For example by means of pinions, via a shoulder The crankshaft, etc., a torque on the drive train Of the engine, which is in addition to the engine Accelerating effect.

The electric machine can also be used as a Part of a drive device decoupled from the motor Drive the vehicle in addition to the engine. For example The electric machine can provide a torque To their own drive train and so In addition to the engine accelerating.

In addition, the electric machine can be advantageous Additionally have a braking effect on the vehicle. The generated energy is at least partial Can be stored in the short-term battery (claim 2). The electric machine is thus operated as a generator. It supports the mechanical braking system When braking the vehicle. For the mechanical Braking is kinetic energy of the vehicle in Heat, which is not generally used any more. In the case of electric braking, however, kinetic Energy of the vehicle into electrical energy. By the at least partial storage Of the electrical energy generated during braking Of the short-time battery, this is achieved Is available to the system (eg Later acceleration of the vehicle). The storage Of the braking energy in the short-term battery leads A further increase in the overall efficiency Of the drive system.

A battery is generally a combination Of two or more parallel or series connected Galvanic elements. In contrast to one Capacitor, in which the energy is essentially in one Electromagnetic field is stored In a battery the storage is essentially electrochemical. A distinction is made between once-use Primary and rechargeable secondary batteries. Preferably, according to the invention Secondary accumulators (accumulators) are used, the After unloading by the supply of a corresponding Energy quantity back into its original state Can be returned and so on a Longer period.

The short-time battery is as described above Compared to those used in conventional vehicles Batteries highly loadable and has a short Discharge time.

Preferably, the discharge duration of the Battery 4 minutes (Claim 3). Under discharge time, the minimum Time duration between full charge and discharge state Battery at maximum permissible continuous load. This (minimum) discharge time is oriented On the one hand in the duration of the usual use Of the motor vehicle Phases of higher demands on drive power. During such a phase the Electric machine the engine while driving the vehicle. The electrical machine is operated by the (Partial) discharge becomes. On the other hand, the duration of the Phases of higher performance requirements Lower performance requirements will. During such a phase, the battery becomes Loaded. The battery may only be unloaded before That the time between two phases with higher Performance requirement essentially for recharging Is sufficient.

Due to the short discharge time of the battery That a high power is achieved at the same time Capacity is provided. Due to the low Battery capacity can reduce their weight. Size of frame And costs are kept low. This leads to, That the drive system is also light, small and inexpensive is

The short-time battery can handle high currents Respectively. The maximum discharge current is More than 10 CA, in particular 15 CA (claim 4). Of the Pulse current is more than 100 A, in particular 120 A (claim 5). The discharge current is set to the nominal capacity Referred to in CA. For example, A battery with a nominal capacity of 4 Ah at 400 MA with 0.1 CA, with 4 A with 1 CA and with 40 A with 10 CA Loaded. The maximum discharge current is the maximum Permissible current, with which the battery over a longer period Period (from full charge to discharge) Can be loaded. The pulse current is Maximum allowable current with which the battery is connected via a Shorter period (two seconds) Can

Due to the high maximum pulse current The electric power supplied by the short-time battery can be reduced Machine over a very short period of time a very Large, by the high maximum discharge current A short period of time. The large or very large drive power of the Electrical machine serves high in the short phases Requirement for the total driving power of the Vehicle to assist the internal combustion engine. Because of the large or very large of the electrical Machine-capable drive power The internal combustion engine then only becomes a relatively smaller one Drive power. It can therefore be appropriate To lower drive power, so Smaller. This is achieved by the fact that, Already in the long phases with low requirement To the total power of the vehicle (during Of which he alone provides the drive) with higher Effective medium pressure (and thus higher efficiency) is operated. This results in a high overall efficiency Of the drive system.

Besides high impulse and discharge currents The short-term battery preferably also has a one High power density of more than 250 W / kg, in particular 300 W / kg (claim 6). So become weight And size of the short - time battery and thus also of the Drive system.

The short-time battery has a total capacity Of less than 1200 Ah, in particular 1000 Ah (Claim 7). Short - time batteries, in particular with high - Performance and high performance Elaborate starting materials and a complex Production process. The cost of a battery Specific power density and output volume Is essentially determined by the total capacity. The use of a battery of low total capacity Leads to low costs for this Drive system.

In the drive system according to the invention, The short-term battery preferably comprises an alkaline secondary system (Claim 8), preferably one Nickel / cadmium system (claim 9). Others are also conceivable Alkaline accumulators such as nickel / iron systems (Claim 10). Advantage of alkaline systems, in particular Of nickel / cadmium or nickel / iron systems Are high energy density, high energy volume, High power density and high performance. The use of an alkaline short-time battery Leads to a drive system of small size And light weight. Also have alkaline Systems, in particular nickel / cadmium and Nickel / iron systems a long service life in the discharged State, are capable of being deeply discharged, can cope with operator errors, Can also be discharged at low temperatures and Mechanically stable.

The short-time battery contains sintered electrodes (Claim 11) or fiber structure electrodes (claim 12). The sintered electrodes can be used as sintered plates Or sintered foil plates. With these A fine mesh nickel wire mesh or a thin, Perforated nickel strip, whereby a Large effective active surfaces and a reduced Internal resistance.

In the case of fiber structure electrodes, the electrode consists From a three-dimensional polypropylene fiber structure, Whose single fibers, coated with nickel, are so Are thin, that, compared to sintered electrodes, the effective Active surface further enlarged and the internal resistance Is further reduced.

The large active surface and the low Internal resistance have high power and energy densities As well as power and energy volumes. The use of short-time batteries with sintering or heating Fiber structure electrodes thus leads to a smaller one And lighter drive system.

The short-time battery is preferably designed such that, That the energy stored in it is also reduced to Power supply of the electric machine for starting Of the internal combustion engine 13). The short-time battery is characterized by high load-bearing capacity And low discharge duration. It should be preferred Fulfill those tasks in the vehicle, Which correspond to this interpretation. The electric machine Needed to start, similar to the short-term Additional acceleration ( "boost"), in the short term High currents. The short-time battery is therefore capacity-dependent Designed so as to always have one to start the Motor Is. Acceleration and starting are carried out Thus from one and the same battery, whereby The expenditure on power electronics is reduced; and Size and weight of the overall system kept low will.

The drive system is preferably designed such that, Characterized in that the electric machine is connected to the drive train Of the motor, in particular rotationally fixed . The coupling can be indirectly over about Pinion, V-belt, a shoulder on the crankshaft Etc., so that the electric machine is operated indirectly A torque is transmitted to the drive shaft of the engine Can Particularly advantageous is a part of the machine, In particular the rotor or the stator, directly with Of the drive shaft of the motor. An advantage Is that then the electrical machine has rotational irregularities Of the drive shaft Can Rotational irregularities occur in internal combustion engines Due to the drive shaft due to the design Acting gas and mass forces.

This can be countered by the fact that, Characterized in that the short-time battery is designed in such a way that the short- Energy stored in it to counteract Wherein the electrical Machine the wave at a negative rotational uniformity With an accelerating (additional) Torque. The For the reduction of the combustion engine Rotational inequalities To be very large. Specifically, one of a conventional one Vehicle battery powered Machine is not sufficiently large cause. The short-term battery used, on the other hand, As explained, can be subjected to high stress in the short term, so that the Electric machine the propulsion shaft with a sufficient And so on Can effectively reduce rotational irregularities. This leads to a protection of the drive shaft and to A reduction in driving noise. Furthermore, The idling speed can be lowered.

In addition, rotational irregularities Can also be reduced by the electric machine The shaft with a positive rotational nonuniformity A braking (additional) torque is applied (Claim 15). Because the short-time battery, like Mentioned above, is advantageously a secondary battery, The energy thus obtained can be stored therein. This has the advantage that the stored Energy can be reused, for example For counteracting negative rotational irregularities, To booting or starting.

Preferably, for optimal reduction Of rotational irregularities both measures Together. The shaft is thus provided with a Rapidly varying, alternating torque, With a negative rotational uniformity With a driving and a positive Rotational uniformity with a braking Torque.

Preferably, the short-term battery is such Designed to cope with the torque generated during braking of the shaft Reduction of traction slip Is loadable (claim 16). Reduction of driving slip Is caused by a reduction in the driving torque, In particular by braking the shaft reached. The short-term battery will be beneficial Gained energy, thereby reducing fuel consumption Is further reduced. A reduction Of the drive slip leads to increased driving safety.

The short-time battery can also be charged When the shaft is used for the purpose of a gear synchronization As well as for a starting and shifting clutch Is braked by the electric machine. Correspondingly Can be stored in the short time battery Energy for accelerating the shaft for transmission synchronization (Claim 17). this function As well as the previously mentioned accelerating functions And braking the vehicle, starting the internal combustion engine, rotation uniformity reduction, Traction slip reduction, etc. can be applied to several Electrical machines. Especially However, these functions are advantageously carried out by a single, From the short-term battery powered electrical Machine. This results in the fact that The drive system is small in size and smaller Weight and is also inexpensive.

If the electric machine is equipped with a generator Function, the resulting energy becomes To charge the short-time battery. Of course The short-term battery can also be replaced by an additional Battery. This is advantageous - in contrast to the short-term battery - a small one Performance / capacity ratio. The second battery Can therefore be referred to the energy stored by it Are not subjected to high loads. This leads to a large Discharge time with low discharge currents. The drive system Thus advantageously has a short-time battery Yet a long-term battery (claim 18). The Long-term battery is advantageous for the power supply Electrical consumer with low power, but High total energy requirements (climate machines, etc.), While the short-term battery electrical consumers With high performance, but low total energy requirement provided. Low-weight batteries are supplied To the available capacity more cost-effectively As heavy duty batteries. Because the highly resilient Short term battery capacity small and the Not long-lasting battery Large, can cost the overall system Are kept low. The invention thus has The advantage of providing a drive system, In which the power supply in the respective type By consumers.

For this reason, Short-time battery, a capacitor is also provided (Claim 19). This is opposite the short-time battery A lower capacity. On the other Page, it can be unloaded and loaded faster. Advantageously, it relieves the short-term battery in particular In tasks where a very high performance Or high energy quantities in a short time Time, eg in the case of reduction Of rotational irregularities.

The drive system comprises a Inverter. This provides the electrical machine Which are used to generate the electromagnetic fields Necessary currents and voltages are more variable Amplitude, frequency, and phase. The short-time battery is present Is connected to the intermediate circuit of the inverter. The same applies to the shortⁱbattery Supporting capacitor. The exact Control option with the inverter has the Advantageous, in particular, the sleeve-varying rotational nonuniformities Quickly and precisely can be.

The invention will now be described with reference to exemplary embodiments And the attached schematic Drawing. In the drawing: FIG.<dl tsize="6"><dt>FIG</dt><dd>An inordinate-schematic representation A first embodiment of the drive system;</dd><dt>FIG</dt><dd>A schematic sectional representation of the Construction of a Ni-Cd short-time battery;</dd><dt>FIG</dt><dd>4 is a schematic representation of a consumption characteristic field Of the internal combustion engine;</dd><dt>FIG</dt><dd>An inordinate-schematic representation A second embodiment of the drive system;</dd><dt>FIG</dt><dd>A schematic exemplary illustration The operation of the drive system of FIG.</dd></dl>

In the figures, essentially functionally equivalent Parts have the same reference symbols.

A drive system of a vehicle, eg 1, as a drive unit A combustion engine 1, in which It is, for example, a four-cylinder ottomotor Is used. The torque generated by the internal combustion engine 1 Can be driven on a drive train 2 on driving wheels 3. In the output direction, Drive train 2 downstream of the internal combustion engine 1 An electric machine 4 is arranged. Follow these A clutch 5, a transmission 6 and an axle drive 7, which applies the torque to the driving wheels 3. In other embodiments (not shown) Is located in the drive train 2 between the internal combustion engine 1 and electric machine 4 another (Control actuated) clutch While braking with the electric machine 4 Of the internal combustion engine 1.

The electric machine 4 - here a three-phase machine In asynchronous or synchronous design - Comprises a stand 8 and a rotor 9. The former Is non-rotatably supported against the internal combustion engine 1, A vehicle chassis (not shown) or a vehicle chassis (not shown) Shown), whereas the latter On an extension of a crankshaft 10 of the internal combustion engine 1 and is rotationally coupled thereto Is. They therefore rotate together, without an intermediate circuit Of a transmission.

The electric machine 4 functions as an auxiliary motor ( "Booster") to the internal combustion engine 1 In accelerating the vehicle. It also serves as a starter for the internal combustion engine 1 And can thus also be a conventional Motor vehicle separately provided starter ( "starter") replace. It also acts as a generator for the Charge of several short-time batteries 11, a long-term battery 13 and for supplying electrical loads And thus replaces a conventional one in the Vehicle alternator.

An inverter 14 supplies the stator 8 Of the electric machine 4 at a high clock frequency Pulse - width modulated voltage pulses Under the effect of the machine inductance Sinusoidal three-phase currents of which Amplitude, frequency and phase is freely selectable.

The inverter 14 is a voltage intermediate circuit inverter And comprises three assemblies: A DC converter 18 (input module), Which dc voltage from a low (Here 12 V) to a higher intermediate circuit level (Here 270 V) and in the opposite direction, An electrical intermediate circuit store 15, Here a capacitor or an arrangement in parallel Capacitors, and a machine inverter 16 (output module), which consists of the DC phase voltage (pulsed) three-phase alternating voltage Variable amplitude, frequency And phase, or - in the case of regenerative Operation of electrical machine Any alternating voltages into the intermediate circuit dc voltage Can be implemented.

The intermediate circuit store 15 is provided with several, Short-time batteries 11 connected in series here With a nominal voltage of 1.2 V each (in the drawing Only three short-term batteries are shown). It results An intermediate circuit voltage of 270 V.

The short-time battery 11 with known per se The basic form is shown in FIG. It is a cylindrical Ni-Cd secondary systems with positive sintered electrodes 23 and negative electrode positive electrodes 24. These are highly porous, spirally wound carriers With large effective active masses. The electrodes 23, 24 are located in tightly closed, cylindrical Steel housings. A separator 25 serves as the separator Plastic fleece. The housing is a cup 26 of nickel-plated Steel sheet. The cup 26 serves simultaneously As a negative pole, the cell cover 27 as a positive pole. By the coatings of the negative electrode 24, Which increase the gas consumption, and additives in the positive Electrode charge 23 is increased And thus the charging time is kept low.

Each short-time battery 11 is continuously connected to Flows of up to 15 CA highly loadable. The discharge time Is then 4 minutes. Short term (up to 2 seconds) An impulse current of 120 A is possible. The Short-time battery has a power density of 300 W / kg and a nominal capacity of 4 Ah at 0.2 CA. they Is fastadbar with streams of up to 2 CA.

Such cylindrical Ni-Cd cells are obtained Usually in household appliances, power tools And telephones, but not in conventional drive systems Of motor vehicles.

The circuit shown in FIG. 1 with the intermediate circuit of FIG Inverter 19, connected in series Short-term batteries 11 can provide high performance in the short term To provide This serves to increase the short-term Additional boosting ( "boosting") of the electrical Engine 4 required power available put. In addition, the short-time batteries 11 supply the Energy for starting the internal combustion engine 1 Supply various high-performance consumers, Such as a climate machine and servo drives (Not shown) with electrical energy. While Such high-performance consumers By mechanical coupling of the internal combustion engine 1, allows for this Available high voltage level an efficiency Cheaper, purely electric drive.

The short-time batteries 11 are also used The storage of the energy that occurs during braking Of the vehicle through the electric machine 4.

In FIG. 1, the DC voltage converter 16 of the inverter 14 on the low-voltage side The long-term battery 13 and various electrical Consumers (not shown) with low power consumption, Such as lighting and electronic lighting Devices. The inverter 14 Can be electricity on low voltage level For charging the long - term battery 13 and supplying the Electrical consumers, on the other hand he can Of long-term battery 13 Low-voltage current remove.

A control device 17 supplies the inverter 14 by appropriate control of its Semiconductor switch at any time, which amplitude, Frequency and phase to be generated by it To have the alternating voltage of the electrical Engine 4 to be delivered .

The control device 17 communicates with one Variety of other control devices: A (not shown) Energy consumption control unit indicates how much energy For charging the short-term battery 11, the long-term battery 13, for the supply of the low voltage and the High-performance consumer is required, so that the Control device 17 may have a braking effect Electrical machine 4.

A motor control unit (not shown) is provided Control device 17, whether and how strong the electrical Machine 4 (eg to achieve a start or Boost function) or (eg for support The mechanical brake). The Engine control unit also controls power, Torque and fuel consumption of the engine 1 Fuel injection, throttle position, fuel injection (Time and amount), ignition timing, etc.

Control of the system electrical machine 4 combustion engine 1 takes place as a function of the fuel consumption Of user-controlled variables such as accelerator pedal position, Preselected driving speed, selected gear ratio, Brake and clutch actuation, Driving characteristics in driving history, etc. and Operational variables such as speed, crankshaft angle, Torque, gas pressure, knocking, traction slip, Driving speed, etc.

In particular, the engine control unit controls The system electric machine 4 - engine 1 so that The engine 1 predominantly, namely, during the long period of time Phases of lower demand on the overall drive power In the energetically favorable range Higher effective mean pressures. The motor 1 then provides solely for the drive of the vehicle. During the short-term phases of higher requirements To the total drive power, eg during start-up Or during overtaking, supports the electrical Engine 4, the engine 1 Same maximum output of the drive system Be designed.

The resultant fuel-saving effect FIG. 3 shows the consumption characteristic diagram Of a four-stroke ottomotor. In this are Torque and effective mean pressure as ordinate and Speed ​​as abscissa. It is registered And three lines b1, b2, b3 are constant-specific Fuel consumption. At b1 the motor 1 has A high one, at b2 a middle one and at b3 one Low specific fuel consumption. Clearly Is that the specific fuel consumption to a Large part of the effective medium pressure, and to a Small part depends on the rotational speed. Shown are Also the (medium-pressure) areas, during which Long - lasting low - demand phases Total driving power Engines of conventional drive systems (Longitudinally hatched) and of the invention Drive system (cross-hatched) will. The internal combustion engine 1 thus becomes predominant With low specific fuel consumption And thus operated at high efficiency.

To start the internal combustion engine 1, The engine control unit sets the target torque on the Basis of stored values ​​that the Temporal desired course of the rotational speed or the torque Of the electric machine 4 during the starting process , Supplemented if necessary by a measurement Of these variables, and a feedback control which Compliance with the requirements.

In addition, an ASR control unit (not Shown) in the presence of a drive slip, That the electric machine 4 is temporarily operated as a generator Brake is to be operated. A transmission synchronization control unit (Not shown) In that the electric machine drives the shaft for transmission synchronization Accelerate or brake.

For counteracting rotational nonuniformities Is the embodiment shown in FIG advantageous. FIG. 5 a illustrates (with a through-drawn Line) the torque Mv of an engine 1 as a function Of the crankshaft angle b. This periodically To an average torque torque fluctuations To smaller and larger torques, In this idealized example, a total of Substantially sinusoidal shape. The relative Large torque fluctuations are caused by the In the engine 1.

In FIG. 5 b, the torque Me, Electrical machine to reduce torque fluctuations As a function of the Wave angle b. The course of this torque Corresponds largely to that of the engine torque Mv, however, is oppositely directed. It There is a reduction or even practically one Disappearance of torque fluctuations In FIG. 5a by the dashed line Is.

In the operation shown in FIG. 5b The negative and positive torque terms same size. The value obtained in a braking phase Energy is thus essentially the same Such as the energy required in the following drive phase.

An example of a modified Operation of the system is shown in FIG. 5c. The man Course of the total torque corresponds to the Of Fig. 5b, but it is a certain amount DMe in the positive direction. The electrical Mechanical energy is supplied to the machine, Whereby a driving effect, for example For short-term acceleration.

Is the course of the total torque shown in FIG. 5b In the negative direction (here Not shown), the electric machine 4 acts in the Medium braking. The resulting energy serves For charging the short-time battery 11.

When counter-rotating vibrations Or when applying an additional braking Torque is the system shaft motor mechanical Energy and converted into electrical energy. The electric machine 4 then acts as Generator.

According to FIG. 4, the electric machine is 4 With a rotary transformer 19 (so-called resolver). This provides a rotational-angle-dependent signal, Which is fed to a control device 18. These Controls the inverter 14 such that rotational irregularities In the manner described above becomes.

When saving the negative values ​​when decreasing a positive Rotation uniformity The short-term battery 11 is controlled by a capacitor 12 Supported. This is also used to provide the While decreasing a negative rotational uniformity Necessary energy.

The control of the reduction of the rotational irregularities From the electric machine 4 To be applied via the control device 17 is carried out, for example, by means of a characteristic field control, in that The control device 17 as the input information angle position Of the shaft 10, the instantaneous mean rotational speed And possibly further operating parameters, such as the throttle position, And from a stored Is the currently expected rotational uniformity As a function of these operating parameters Is determined. Another possibility is actually To determine rotational nonuniformities. A combination of regulation is also possible And control.

From the determined value for the current Rotational uniformity, corresponding (antiphase) Values ​​of the electromagnetic action device Applied, rapidly varying torques Which may be a positive or negative one Additional torque of desired strength additive Is superimposed.

It will therefore be a fuel-efficient, compact And light drive system, With which, in addition, rotational nonuniformities are also counteracted can be.