DE102007017239A1 - Method for building up torque reserves in a hybrid drive - Google Patents

Abstract

A method of operating a hybrid drive having an internal combustion engine and an aggregate connectable thereto, the method comprising: operating the internal combustion engine at a first discrete operating point corresponding to a first generation torque; Setting a second discrete operating point corresponding to a second generating torque different from the first filling level. The aggregate provides a compensation torque that is opposite to the change from the first generation torque to the second generation torque. The invention further relates to a control device for controlling the torque provided by the unit according to the method.

Description

State of the art

The Invention is based on a hybrid drive with an internal combustion engine and an electric machine.

At the Operation of the internal combustion engine will improve the driving dynamics or to compensate for torque changes by switching on or separating torque sinks of the internal combustion engine, depending on the desired Acceleration too high generation torque, d. H. an excess torque Compensation of the excess torque can then be quickly reduced to a corresponding acceleration to realize, with the engine already in a corresponding Operating area was driven. For example, in increasing the filling there is an excess torque. However, that should be done by the surplus increased Generating torque to drive only if this the desired Acceleration requires, otherwise a jerky acceleration results.

Therefore will be according to the state the technology of the ignition angle changed so that opposing interventions of the internal combustion engine by deteriorating the Zündwinkelwirkungsgrads the excess torque compensate, creating an undesirable Acceleration is avoided. To the built-up torque reserves it is only necessary to compensate for this by Adjust the ignition angle repealed.

To the however, one is the degree of compensation of the excess torque by the maximum adjustable ignition angle limited. On the other hand, only an excess can be obtained by reducing the torque be compensated. Furthermore, the change in the ignition angle the ignition angle efficiency impaired.

Disclosure of the invention

The The invention provides a method of operating an internal combustion engine and at least one unit before that with the internal combustion engine is connected, wherein the internal combustion engine on one for the internal combustion engine optimal or for other reasons desirable Operating point defined by one or more operating parameters is, is operated. Operating on the selected operating point can lead to a torque, that differs from the torque required for the drive is or is currently for the drive desired is. The difference becomes, for example, beside the compensation by annihilation by means of ignition angle adjustment, according to the invention of the connected aggregate either dismantled, d. H. destroyed, or recorded and converted into storable energy and cached. As an aggregate, an electric machine can be used, the the excess (or still missing) torque compensated to cache it (or to generate). By ignition angle adjustment Although the engine can be compensated for part of the torque However, this goes with a deterioration of the efficiency is accompanied by a low maximum possible torque destruction limited. The invention allows a more flexible and far-reaching Compensation by intermediate storage and / or by dismantling (or destruction). As an aggregate, an electric machine is preferably used, the torque caches as electrical energy and / or the Torque destroyed, for example by conversion to heat. Farther Another combustion engine in question, by appropriate Triggering, for example the ignition angle or other parameters, can perform the torque compensation in whole or in part. Further a fuel cell can be used that, over one Generator, absorb mechanical power and heat and / or can convert chemical energy. In the following description will be often used as an aggregate an electric machine, for example the electric machine, the traction power in a hybrid drive generated and mechanical power when recuperating into electrical, storable power or energy converts.

The inventive method allows the compensation of excess torque, which is not limited by a maximum ignition angle. Furthermore, despite built-up torque compensation of the engine with a higher one ignition angle work. In addition, can be to make the driving dynamics more flexible, with a torque compensation can be built more dynamic and reduced, especially at low speeds of the internal combustion engine. Another advantage is that the operating parameters of the internal combustion engine in other areas. In particular, can be increase the generation torque more flexibly and to a greater extent, without an undesirable Acceleration or an undesirable ignition angle to have to accept. The inventive method also allows a finely controlled and time-dynamic control an acceleration.

Changes in discrete operating points result in strong torque fluctuations For example, when switching off or on of individual cylinders or cylinder groups when turning off or on the turbocharger, or the abrupt change from the rich mixture to lean mixture or vice versa, resulting in strong step-shaped torque fluctuations in both directions, ie surpluses and shortage. Such step changes may also result from switching operations, such as switching the hub from low to high, or vice versa. The change of the stroke preferably comprises the change of the valve lift of at least one intake valve, a part of all or all of the intake valves. Further, the change of the stroke preferably includes the change of at least one exhaust valve, a part of all or all of the exhaust valves.

Step-like changes are also associated with sudden load point changes, for example when adding or disconnecting decelerating or accelerating Elements, d. H. Torque sinks or sources.

The On the one hand, this invention allows these fluctuations despite operating point / or To compensate for operating mode change to a large extent, and on the other hand, a compensation in both directions. Furthermore, strong Reductions in ignition angle efficiency be avoided by Zündwinkelfehleinstellungen used only to a limited extent or not at all for compensation and instead the electric motor provides compensation.

The underlying inventive concept is in a Switching, which results in a sudden change in torque has, for example, in the context of an increase in the degree of filling for the construction of Torque reserves, not only the internal combustion engine, but also the electric motor to compensate for a sudden increase or fallen generation torque to torque compensation in both directions as well as in higher To make scope and to be able to set by controlling the electric machine targeted.

Therefore recorded, according to a preferred embodiment the invention, the controller or another element the occurrence or the imminence of a mode change, with a sudden change the torque generated by the internal combustion engine is connected, and changes the torque that is provided by the electric motor to the erratic change the torque generated by the engine at least partially to compensate. Is the change positive, d. H. the torque jumps from a low value a high value, in addition to Compensation by means of electric motor of the Zündwinkelwirkungsgrad deteriorated be to reduce the torque difference by partial removal of the Internal combustion engine generated torque (i.e., the generation torque) to reduce. In other words, in addition to the electric motor, which serves absorbs part of the excess torque, a deterioration of the ignition angle efficiency to reduce the torque difference with the torque jump accompanied.

It However, it should be noted that the reduction of torque or the associated Share of compensation by means of deterioration of the ignition angle is limited by the maximum ignition angle to be set. In one Example is the ignition angle only be worsened so far that a maximum of 20% of the production torque by deterioration of the ignition angle efficiency can be reduced. Alternatively you can also other shares, eg. 25% -50% or 30% -45% or 40% maximum by change, d. H. by deteriorating the ignition angle efficiency as the maximum compensation be used. Further, by deterioration of the generation torque only torque can be reduced. The compensation is therefore on only one direction limited, it can only too high generation torques are reduced; too low generation torques can through Zündwinkelveränderungen can not be compensated.

Therefore The compensation by the electric motor offers an alternative Compensation possibility, for the ignition angle adjustment can be added, the positive and negative torque differences can compensate, and provide a wider range of compensation covering, in particular in combination with the ignition angle change.

A change in the generation torque, ie the torque generated by the internal combustion engine is caused by the change in the energy generated by the ignition of a cylinder of the internal combustion engine and by the change in the energy transfer or the efficiency with which the explosion energy within the cylinder as rotational energy of the drive shaft of the internal combustion engine. Further, the generation torque changes by adding or disconnecting torque sinks (output, accumulator charging devices or the like) or torque sources. In particular, the energy released by ignition of the cylinder contents depends on the fuel quantity, the fuel concentration, the turbocharger precharge pressure, the lift, and the number of cylinders participating in the power generation. Furthermore, there is a sudden change in the generation torque in particular by changes gen the number of cylinders ignited based on the number of all cylinders, the amount of fuel or the fuel concentration. Other sources of abrupt changes are due to changes in the precharge pressure (eg, by a turbocharger), the cylinder stroke, and / or the engagement / removal of torque sources or torque sinks.

All these (and other) parameters that represent the operating point or operating mode of the internal combustion engine and influence the generation torque, can change from one discrete value to another discrete value and thereby causing a jump in the generation torque. Examples for such changes are: on / off individual cylinders, the turbocharger and change from one hub to another hub or from rich to lean fuel mixture or vice versa, as well as adding or separating elements, which slow down or accelerate the drive shaft.

to Optimizing the efficiency of a hybrid engine will make such changes generally, resulting in a discrete decrease / increase of the generation torque. According to the invention this discrete decrease / increase, at least in part, due to the adjustment compensated for the torque of the electric machine.

is therefore, for example, a desired acceleration or a positive dynamic of the moment to be set (eg by Change of operating mode or connection of consumers), this will be the degree of filling of the internal combustion engine increases, causing a higher Generating torque is provided. To avoid that higher Generating torque, which corresponds to a second, higher degree of filling, to a undesirable Acceleration leads, At least a portion of the generation torque surplus, i. H. the difference between the second, higher Generation torque and the first, lower generation torque, from the electrical Motor received, instead of being passed on to the drive. The first generation torque is the torque, that the engine generates before increasing the charge, whereas the second generation torque corresponds to the torque that the Internal combustion engine in another operating point, preferably in terms of efficiency is optimal, for example, at increased filling generated and its surplus across from At least partially compensated for the first generation torque or destroyed, resulting in undesirable accelerations to avoid. In the same way, the compensation of a defect be achieved at generation torque, in which the electric motor Torque in height generated, which corresponds to the defect. The operation of the internal combustion engine For example, if the generation torque is too low, if this corresponds to a high efficiency of the internal combustion engine and the internal combustion engine at a higher generation torque would degrade its efficiency or the overall efficiency of the drive. Consequently let yourself for example, the Zündwinkelwirkungsgrad improve or optimize, with the electric motor the lack of (or excess) torque compensated for this operating point.

By receiving at least a portion of the excess generating torque The electric machine can lower the internal combustion engine Dimensions or not used to compensate for the generation torque increase be, whereby the internal combustion engine at a higher or optimal ignition angle efficiency can work. While the inclusion of the excess generation torque in the internal combustion engine to a loss of energy or a changed Efficiency leads, can the at least partial compensation by means of the electric Machine can be used to control the excess generating torque, d. H. the built-up torque reserves to convert into electrical energy, in an electrical energy storage, for example in a Accumulator, cached and retrieved later can.

to at least partial absorption of the torque reserves is the electrical Machine with the internal combustion engine for the transmission of mechanical power connected, for example via a switchable clutch or over a permanent connection, the electric machine that of the Internal combustion engine supplied mechanical power in electrical Performance that can be at least partially stored.

By compensating for the increased generation torque by means of a connected accumulator electric machine, the power flow may be changed in an alternative cumulative manner than by a change in the firing angle, for example, a change in the control current if the electric machine is a DC motor. Preferably, the charge balance of the battery connected to the electric machine is taken into account in order to avoid overcharging in the intermediate buffering of an excessive generation torque. According to a preferred embodiment of the invention, the electric machine is a synchronous machine by means of electric current or by means of egg nes permanent magnet is energized. The operating state and / or the current balance of the synchronous motor can be adjusted by means of the frequency, phase position and / or height of the voltage or the current which is applied to the stator windings or flows through them.

The Buffering or compensation of the increased generation torque can be provided by the electric energy storage alone. Alternatively, the internal combustion engine can be consulted, its firing angle changed is going to be a part of the raised Generating torque via Reduce efficiency deterioration. According to one embodiment, the Difference between the increased, second generation torque and the first, initial generation torque Completely or partially stored in an electrical energy store, preferably after conversion of kinetic energy by means of electrical Machine into electrical energy. If, for example, the power consumption of the electrical energy storage is limited, for example at a rechargeable battery with maximum charging current, can at a high Difference between the second generation torque and the first Generation torque of the internal combustion engine are involved, by a part of the torque surplus reduce or compensate, leaving the remaining proportion corresponds to a converted electrical power, the smaller as a maximum charging power. In determining the share, with which the electric machine the excess generating torque in converts electrical energy and in the electrical energy storage stores, may depend on the state of charge and / or the temperature of the depend on electrical energy storage. For example, at an elevated one Temperature or high charge level of the electrical energy storage only a lower electrical power to absorb the generation torque surplus be used, as at low temperatures or empty battery. The temperature and / or the charge level or the still permissible charge current of the electrical energy storage is therefore preferably in the control of the internal combustion engine and the electric machine with a.

In a further embodiment of the invention is the excess generation torque, d. H. the difference between the second generation torque and the first generation torque by a change in the ignition angle or ignition angle efficiency degraded or absorbed by the internal combustion engine, as far as the difference does not exceed a threshold. According to the invention, the excess generation torque, which is above the threshold value of the electric machine converted into electrical power and in the electrical energy storage cached. The threshold value may correspond to an excess generation torque. in which the efficiency of the internal combustion engine by a changed ignition angle is still acceptable. Alternatively, at an excess generation torque, which is below a certain threshold, the excess difference of the generation torque as electrical power over the electric machine to be stored in the electrical energy storage. The threshold may in this case, for example, a torque surplus corresponding to a maximum charging current or nominal charging current leads.

Preferably corresponds to the first generation torque of a drive power, the second generation torque minus the to the electric Engine and / or delivered to the engine torque equivalent. Alternatively, the second generation torque may be the delivered to the internal combustion engine and / or to the electric machine Performance, the required drive power and an additional Acceleration performance correspond. In other words, the increase the torque from the first generation torque to the second generation torque not Completely by taking the surplus compensated by the electric machines and / or by the internal combustion engine so that only part of the surplus is compensated and the remaining portion to a purposefully controlled acceleration, d. H. increase the drive power is used. Further, by discharging means of the internal combustion engine and / or by means of the electric machine Torque excess overcompensated so that's available standing drive power despite increase of the generation torque is reduced. This allows a powered vehicle targeted be braked, preferably by partial or complete conversion of Power difference between generated power and drive power in electrical power to be stored in the context of recuperation through the electric machine. Because of partial, complete or excessive compensation one raised Generating torque according to the invention an electric machine is used, which operates in this operating state as a generator, can, for example, in combination with the on the internal combustion engine based compensation, flexible generation and flexible Control of the drive power can be provided.

Due to the additional combination with the electric machine, the otherwise existing due to a maximum existing ignition angle of the engine restrictions significantly expanded. At the same time the control is provided more flexible and can be provided more dynamic over time. In addition, the total efficiency is increased by the compensation by means of the electric machine, since the compensation does not lead to the destruction of mechanical energy, but at least partial caching in electrical energy, which in turn can be retrieved for drive purposes. The compensation can be provided in part by the internal combustion engine and / or partially or completely by the electric machine, which allows a further degree of freedom in the control. Thus, despite the maximum possible change in the ignition angle, the generation torque can be increased while at the same time reducing the drive power. The resulting difference can be compensated not only by the internal combustion engine, but also by the conversion of the excess torque into electrical energy to be stored. If the ignition angle conversion and the braking generator operation of the electric machine is not sufficient, a conventional brake for partial compensation of the excess torque can be used.

In an execution the method according to the invention a differential control value is provided, which has a limit above of the first generation torque, above which the excess generation torque Completely the electric machine is supplied to the intermediate storage. The torque range between this limit and the first Generation torque is equal to the proportion of the internal combustion engine and / or the drive for additional acceleration performance supplied becomes. The difference threshold refers to the difference between the first and second generation torque, this difference, the excess torque corresponds to the electric machine, the internal combustion engine with changed ignition angle and additional Acceleration performance is distributed. The difference threshold marks the limit from which the excess generating torque Completely taken up by the electric machine and converted into electrical energy becomes.

Lies the difference threshold at zero, the total excess generating torque of the electric Machine supplied, where a maximum difference threshold a limit below corresponds to the excess generation torque through a changed one firing angle intercepted or compensated. The maximum difference threshold For example, is a maximum limit for the change of the ignition angle or a limit for the change of the ignition angle, from the efficiency of the internal combustion engine or the overall efficiency of the hybrid drive falls below a certain limit. Alternatively, the compensation be also allocated inversely, so that a first to be compensated Differential torque range, the values below the threshold corresponds, is compensated by the electric machine, during the about that lying proportion of the excess torque by change, d. H. Deterioration of the ignition angle efficiency is caught.

Divided according to the invention the difference between the second generation torque and the first generation torque, d. H. the excess torque, on 3 power sinks, d. H. the electric machine operated as a generator, the internal combustion engine with changed ignition angle and an additional one Drive power to accelerate a vehicle. The shares are preferably positive, with two of the three parts also zero could be. Furthermore, negative shares are conceivable, for example, a negative additional Acceleration share, which leads to the deceleration of the vehicle. Further can the proportion of the electric machine or the internal combustion engine be negative, in which case no production torque recorded is, but is delivered. In the case of the electric machine this means the operation as a drive motor and in the case of the internal combustion engine does this mean a firing angle setting, the extra torque rather than a portion of the excess generation torque reduce or compensate. This is the case for example if an operating point of the internal combustion engine, the one too high Torque corresponds, for example, in terms of efficiency better or optimal, and the resulting excess torque is intercepted by the electric machine and as described above is transformed into storable electrical energy.

The division of proportions may depend on the desired drivability (ie, keeping the speed, acceleration, deceleration constant) and the desired amount of excess torque converted to electrical power. The proportion of the electrical machine may depend on the readiness of the electrical storage to absorb energy, which in turn may depend on the state of charge, the nominal charging current and / or the temperature of the electrical storage. Furthermore, the proportion of the internal combustion engine can depend on the operating point at which the internal combustion engine is to operate, ie in which efficiency, with which fuel / air mixture, etc. Thus, for example, it may be desirable to change the fuel quantity or the fuel con tion to heat the catalyst, with a deterioration of the efficiency is deliberately accepted, which also leads to a torque excess / torque deficiency, which in turn must be intercepted or compensated by the electric machine.

The inventive concept is further implemented by a controller, the one Hybrid drive with at least one electric machine and one Internal combustion engine controls, whereby the control with the individual Components of the hybrid drive is connected to the degree of filling of the internal combustion engine and the torque absorption of the electric To control the machine. Furthermore, the control device can be set up be to control a controllable clutch, the internal combustion engine partially or completely connects to or disconnects from the electrical machine. The control device according to the invention includes entrances, receiving a desired signal representing the desired acceleration, for example, the signal of an accelerator pedal. According to the invention Set up control device, a degree of filling for the internal combustion engine provide, which leads to a torque output, which an excess torque so that the internal combustion engine is not only sufficient Torque for a desired one Acceleration holds, but about that In addition, the electric machine supplied with mechanical power. The control device is therefore set up according to the invention, to control the electric machine, preferably its excitation, to achieve that the electrical machine partially or completely the excess or to be compensated torque in electrical energy to be stored transforms. If the electric machine, the excess torque of the engine not completely A part of the torque can be absorbed by a corresponding change the ignition angle be intercepted and / or converted into an additional, controlled acceleration. Is the desired Acceleration equal to zero or less than zero (for example during a Braking process), so the excess torque at least partially converted into electrical energy to an extent which corresponds to the deceleration or keeping the speed constant.

The Control device can therefore the degree of filling of the internal combustion engine increase, leaving an excess torque produced by conversion into electrical energy, by changing the ignition angle, or by controlled acceleration of a vehicle or by a combination of these can be compensated. Furthermore, an excess torque by elevating the degree of filling of the internal combustion engine and generated by braking the vehicle be, with this excess torque by means of ignition angle change and / or by converting the excess torque can be compensated for in electrical energy. The control device is set up according to the invention, the respective proportions of the excess torque to be compensated in corresponding ignition angle, Excitation control of the electric machine and / or targeted Accelerate the vehicle implement.

Therefore are the outputs the control device preferably set the ignition angle to control, preferably further, the inputs are arranged, the To detect state of charge of the electrical energy storage, with electrical machines is connected and loaded by this to the share of surplus, to determine the torque generated by the internal combustion engine, the is converted into electrical energy and from the electrical Memory should be stored. Preferably, the controller is set up not to exceed a certain charging current, that of the nominal value, the temperature or the state of charge of the accumulator depend can. According to the lower charging currents can be so by a suitable change the ignition angle of the internal combustion engine are compensated, so that a larger proportion the excess torque through the changes the ignition angle is caught up to an overload to prevent the energy storage.

alternative the control device preferably comprises outputs which are set, the ignition angle to control and inputs, which are set up, a state of charge one with the at least to record an aggregate connected electrical energy storage, the over the desired Acceleration exceeding proportion of the torque generation of the Internal combustion engine by controlling the torque absorption or torque output the at least one unit depending on the state of charge of the electrical energy storage is saved by this, and partly by change the triggering of the ignition angle is reduced by the control of the internal combustion engine.

Brief description of the drawings

embodiments The invention is illustrated in the drawings and in the following Description closer explained.

It demonstrate

1 is an overview diagram of a hybrid drive system with which the inventive Procedure can be implemented.

2 shows an exemplary course of working sizes, based on which the mode of action of the method is explained.

Embodiments:

This in 1 shown hybrid drive system includes an internal combustion engine 10 and an electric machine 20 ,

In the in 1 Example shown is the internal combustion engine 10 via a switchable coupling 30 with the electric machine 20 coupled. In an embodiment of the invention, not shown, the internal combustion engine is coupled directly to the electric machine. The electric machine is via a shiftable output clutch 40 with an output connection 50 connected. The drive connection 50 is intended to be connected to wheels of a vehicle in order to drive them. The internal combustion engine 10 obtained from a compression device 60 For example, a supercharger, an air-fuel mixture. In particular, the air / fuel mixture is the individual or groups of the four cylinders of the internal combustion engine 10 received, controllable. Alternatively, the internal combustion engine 10 Get the fuel from a fuel supply, for example from a fuel pump.

The electric machine 20 is about a charging device 70 with an accumulator 80 connected, which serves as an electrical energy storage. The entire system is powered by a controller 90 controlled. For this purpose, the compression device 60 with the controller 90 connected to receive and execute control signals. Further, the controller 90 with the internal combustion engine 10 connected to the individual firing angle or all the firing angle of the internal combustion engine 10 to control at the same time. Preferably, the controller 90 with the internal combustion engine 10 connected to deliver individual ignition pulses for igniting the air / fuel mixture in the individual cylinders.

The control 90 is also with the switchable coupling 30 connected to the drive shafts of the internal combustion engine 10 with the electric machine 20 can be connected controlled.

The electric machine 20 is with the control device 90 connected to be supplied by this with an electrical excitation power. Alternatively, the control device 90 Signals to the electric machine 20 send information about the magnitude of the excitation current. The control device 90 also receives from the electric machine 20 Speed signals representing the rotational speed of the electric machine. Furthermore, the control device receives 90 a voltage signal representing the voltage on the stator winding of the electric machine. The electric machine 20 is also via a charging device 70 with the accumulator 80 connected, the charging device 70 to the accumulator 80 flowing electricity and / or the battery 80 to the electric machine 20 flowing current controls. Furthermore, the control device receives 90 a current signal from that of the accumulator 80 flowing current or to the accumulator 80 flowing current. The control device 90 is also ver with the output clutch connected to control this. The control device 90 also has an input (not shown) for detecting the position of the drive shaft of the internal combustion engine 10 and a device for determining the state of charge of the accumulator 80 , preferably via the charging device 70 integrated flowing electricity. The control device 90 also has an input for signals representing the desired acceleration or drive torque. For this purpose, the control device 90 be connected to an accelerator pedal and / or with a brake pedal.

Therefore, the controller controls to change the operating point 90 the charger 60 to increase the degree of filling. Alternatively, instead of a charging device 60 also the setting of a throttle valve can be controlled. This generates the internal combustion engine 10 a higher torque. The increase can also be caused by adding cylinders or changing the cylinder stroke. This increase of the torque is compensated by the change of the ignition angle of the internal combustion engine 10 and preferably additionally by the control of the electrical machine 20 as a generator that converts at least a portion of the power generated in the engine into storable electrical energy. For this purpose, the control device controls 90 the electric machine 20 with a corresponding excitation current, the clutch 30 is at least partially closed to a transfer of mechanical energy before internal combustion engine 10 to the electric machine 20 to enable. The of the electric machine 20 generated electrical energy is for example partially used to supply the electrical system of a motor vehicle. The electrical energy is transmitted via the charging device 70 the accumulator 80 fed. The charging device 70 is preferably also configured for controlled power output, for example, to the electrical machine or to the electrical system. The accumulator may be a lead-acid battery, a NiCd or NiMH, or another accumulator having a relatively high energy density, has a high discharge / charge current and a favorable price / capacity ratio.

The 2A and 2 B show an example course for working variables of a hybrid drive, for example, the in 1 illustrated hybrid drive system.

The 2A shows the course of the externally requested torque reserve, which corresponds to a torque surplus, and which results, for example due to desired speed changes, ie accelerations and / or occurring slopes. The cause may also be that the valve lift (of the one or more intake valves and / or the exhaust valve or a respective part thereof) is changed, a turbo is engaged, a supercharger throttle is opened, a cylinder group is engaged, or otherwise the operating point or the load point is moved abruptly. Between the two points t ₀ and t ₁ and after the time t ₆ , no torque reserve is requested from the outside, or the generation torque is not increased. Further, in these time intervals, it is not necessary to increase the degree of filling to produce a higher torque. However, between the times t ₁ -t _{6 there} are different torque reserves, that is, an excess of generation torque, wherein the surplus of generation torque and the torque reserves are to be provided by the internal combustion engine, for example, by changing the degree of filling of the internal combustion engine, or by changing the number of cylinders, by switching on / off a supercharger or turbo or by reducing the stroke or by other measures described above.

The 2 B shows the corresponding course of the output to the output torque M _output , as well as generated by the internal combustion engine generation torque M _generated . Furthermore, the shows 2 B the power consumed by the electric machine torque M _{aufn, el,} and the maximum degraded by the combustion engine or by changing the ignition angle to be compensated torque _{aufn M, max.} The index "aufn" in this context means the compensation by recording, ie conversion into storable energy or the compensation by degradation, ie destruction of torque.

The output to the output torque M _output is constant at all times. The generation torque M _generated is constant between the times t ₀ and t ₁ and after the time t ₆ 'and corresponds to the first generation torque according to the invention, which is generated at a first degree of filling. Since after the time t _1, the required torque reserve increases or the operating point / operating mode is changed, see. 2A , and the torque surplus is greater than zero, the torque generated by the internal combustion engine is increased.

In order to keep the same time, the power delivered to the output torque M _output constant, the amount by which _produces the second generation torque M will exceed the to be kept constant output torque M _dispensing degraded by variation of the ignition angle of the engine from the engine. The in reserve or the excess torque, which is characterized by the distance of the second generation torque M _generated to the output torque M _output , can be released immediately when the ignition angle of the internal combustion engine is switched to the original state, so that the proportion of the generation torque that is dissipated by the internal combustion engine becomes zero.

Between the times t ₂ and t ₃ , the operating point changes again and the excess torque decreases, so that, as in 2 B is shown, which is reduced by the internal combustion engine by reducing the ignition angle torque compensated or reduced torque share. Due to the inertia of the engine, the setting of the engine and the fuel mixture supply of the internal combustion engine, changes in the desired torque reserve are not abruptly implemented, but require a certain settling time, which have substantially the form of a negative-exponential development. When changing the operating point by adjusting the ignition phase and the ignition angle, the generation torque can be changed within one or within a few ignition cycles.

From the 2A It can be seen that between the times t ₃ and t ₄ and the times t ₄ and t ₅ particularly high torque reserves are built up, so that the generating torque has a high excess portion. The second generation torque, as shown in 2 B can be seen, between the times t ₃ and t ₅ particularly high values, at the time t ₃ '(due to the above delay, or, if only a negligible delay occurs already at t ₃ ) generating a generation torque is caused, that can no longer be completely compensated by changing the ignition angle of the internal combustion engine. This limit, in the 2 B shown as dashed horizontal, marks a smallest possible ignition angle, or a firing angle at which the internal combustion engine reaches an efficiency that is below predetermined minimum requirements.

Therefore, in order to keep the output torque M _output constant, further measures must be taken to completely destroy or compensate for the excess. This is achieved according to the invention, in which between the times t ₃ 'and t _5, the electric machine is connected to the engine and is driven so that it also receives a share of the excess torque to be destroyed. The absorbed by the electric machine share is in the 2 B shown as a hatched area and is above the limit (dashed horizontal), which is characterized by the maximum torque to be absorbed by the internal combustion engine. Between the times t ₃ 'and t ₅ , the ignition angle of the engine is not changed and remains unchanged at the maximum possible setting. Since between the times t ₃ 'and t _5, the electric machine is used to compensate for portions of the generation torque by recording, resulting from the lower inertia of the electric machine, a much faster setting or settling to the target value, especially at low Speeds and change in the operating point of the internal combustion engine by changing the amount of fuel supplied or the fuel / air concentration, in particular by changing the amount of air. This can be seen from the curve slopes of the curve in the interval directly after the time t ₃ 'and directly after the time t ₄ , which characterize the higher dynamics of the electric machine. The proportion of the torque which the electric machine has to absorb is lower between the times t ₃ 'and t ₄ than between the times t ₄ and t ₅ , since a higher torque excess is generated between t ₄ and t ₅ than between the times t ₃ and t ₄ . At time t ₅ , the generated excess torque falls to a value below the maximum value which can be compensated by the internal combustion engine by changing the ignition angle. Therefore, the generation torque at time t _{5 reaches} a value that can be completely compensated by the engine by changing the ignition angle, so that the excess torque is exclusively compensated by the engine. From time t ₆ , the torque surplus falls to zero, which also causes the generation torque with a certain inertia, which is caused by the internal combustion engine, to fall back to the output torque, which is delivered to the output.

Between the times t ₃ 'and t ₅ , the electric machine receives a torque which is above the maximum torque to be absorbed by the internal combustion engine. Since the electric machine receives the torque by converting and storing electrical power, the dashed area represents the energy that can be stored in an accumulator to provide the torque reserve. The corresponding power to be stored electrically can be limited by the maximum charging current of the accumulator.

In one embodiment, not shown, not the internal combustion engine but first the electric machine is used to compensate for the excess torque. That is, if an excess torque threshold is not exceeded, the electric machine takes over the torque compensation, and the internal combustion engine preferably operates at an optimum ignition angle efficiency. It can, as in the 2A and 2 B that the torque output at the output is constant. The internal combustion engine is controlled in such a way that it operates in accordance with the specifications given in 2A is shown, generates a torque. In this embodiment, therefore, results in the same basic course as in 2 B , wherein the curve M _generated corresponds to the torque _generated by the internal combustion engine, and at the same time represents the torque received by the electric machine, that is converted into electrical cal energy. Furthermore, the electrical energy store to be charged, for example an accumulator, can be charged 80 , Have a maximum charging power, so that the torque which receives the electric machine is limited. This leads to a curve as in the 2 B where M is _{on, max} . corresponds to the maximum torque that can be absorbed by the electric machine due to the limited charging current. The additional torque is then reduced by changing the firing angle of the internal combustion engine from the engine, which thus compensates for a share of the excess torque, as well as the electric machine. M _{max, max} thus corresponds to the torque which is used for at least partial compensation of the generated torque, ie generally by ignition angle adjustment, generator operation of the electric machine, by additional vehicle acceleration or by another unit by destruction or conversion into storable and / or not storable energy to the internal combustion engine (or another drive unit) is withdrawn.

This results in a course, as he also in the 2 B between the times t ₃ 'and t ₅ , wherein the dashed area corresponds to the torque which is compensated by the internal combustion engine or degraded by efficiency deterioration. Due to the reversed tasks, the dashed area denoted by _{Mnn, el} would then be compensated by the internal combustion engine and not by the electric machine or by the destruction of the motion be absorbed.

The basis of the 2A and 2 B The illustrated embodiments illustrate exemplary inventive methods in which the proportion of torque received by the electric machine and the proportion of torque received by the engine by changing the firing angle are determined by limits, with either the electric machine or the internal combustion engine receives the base load of the reserve torque and the respective other component receives the excess reserve torque. Thus, the component that receives the base load is 100% full at a high excess torque required by operating point settings. Therefore, a further embodiment of the inventive method provides for a division of the proportions of the electric machine and the internal combustion engine into equal parts, or depending on the temperature of the internal combustion engine and / or the electric machine of the state of charge of the electrical energy storage and / or the desired driving dynamics. In this case, it is preferably considered that the electric machine and the internal combustion engine basically have different ways of reducing the excess torque, which have different dynamics. For example, if the electrical energy store can provide the electric machine with high power in the short term, the compensation of the surplus torque can be reduced faster (for example, for acceleration), when the torque reserve is largely formed by the electric machine, and not by the internal combustion engine, when the engine is running at a low speed.

In another embodiment the invention, the efficiency of the internal combustion engine is taken into account, so that the internal combustion engine contribute only to the extent to the excess formation can, as a certain minimum efficiency due to the changed firing angle not fallen below.

alternative or in combination with this, the efficiency of energy storage considered by the electric machine, in particular Warmth- and friction losses of the electric machine, the charging device and the electrical storage.

In another embodiment, only a portion of the generation torque generated by the internal combustion engine is compensated for by the internal combustion engine and / or the electric machine as surplus torque, but forms a torque component that is used to accelerate an engine Vehicle is used. Although in the 2 B For example, due to a driver's desire, it may be necessary to generate a lower or higher excess torque in the electric machine and / or in the electric combustion engine than a constant output torque would require. Therefore, an embodiment of the invention includes a method in which the operating point that affects the output power and / or the generation torque results from the excess torque of the internal combustion engine, the excess torque of the electric machine and the torque used for the Driver performs the desired acceleration.

The maximum total excess torque results from the maximum torque generated by the internal combustion engine by change the ignition angle can be compensated, and from the maximum excess torque that the maximum torque corresponding to the electric machine due to mechanical constraints or due to maximum charging currents of the accumulator can record.

Claims (10)

Method for operating a hybrid drive, comprising an internal combustion engine ( 10 ) and at least one aggregate ( 20 ), the method comprising: operating the internal combustion engine ( 10 at a first discrete operating point corresponding to a first generating torque; Setting a second discrete operating point corresponding to a second generating torque different from the first filling level, characterized in that the at least one aggregate ( 20 ) provides a compensation torque that is opposite to the change from the first generation torque to the second generation torque. The method of claim 1, wherein the at least one Aggregate at least one intended for driving electric machine, a synchronous motor, a self-excited or separately excited DC machine, an asynchronous motor, another internal combustion engine and / or an electric generator with a fuel cell connected thereto. The method of claim 1, wherein the compensation torque is converted by the at least one aggregate into storable electrical energy when it is positive, and compensation torque is generated by at least one aggregate when it is negative, the minima at least one unit comprises at least one electric machine and / or at least one further internal combustion engine ... The method of claim 1, wherein the compensation torque less than or equal to the difference between the second generation torque and the first generation torque. Method according to claim 1, wherein the internal combustion engine ( 10 ) reduces the difference between the second generation torque and the first generation torque by changing the ignition angle. The method of claim 1, wherein a portion of the second generation torque from the aggregate ( 20 ) is compensated when the difference between the second generation torque and the first generation torque is above a threshold difference, and that portion of the difference between the second generation torque and the first generation torque that is below the threshold difference is, from the internal combustion engine ( 10 ) by means of variation of the ignition angle of the internal combustion engine ( 10 ) is compensated. The method of claim 1, wherein the difference between the second generation torque and the first generation torque is positive and minus a difference threshold completely from the at least one aggregate. 20 ) and an output ( 50 ) to provide a desired acceleration, the difference threshold being between zero and a maximum difference threshold. The method of claim 1, wherein a first portion of the difference between the second generation torque and the first generation torque from the generator-operated aggregate ( 20 ), a second portion of the difference between the second generation torque and the first generation torque from the internal combustion engine ( 10 ) is compensated by ignition angle changes and a third portion of the difference between the second generation torque and the first generation torque of an output ( 50 ) for acceleration of a vehicle, wherein the first, second and third portions together constitute the difference between the second generation torque and the first generation torque, and each between zero and the difference between the second generation torque and the first generation torque Generation torque are variable. A method according to claim 7, wherein the first portion of a capacity available for storing electrical energy of a working with the generator as at least one unit ( 20 ) connected memory ( 80 ) depends on electrical energy. Control device ( 90 ) for controlling the operation of a hybrid drive, the at least one unit ( 20 ) and an internal combustion engine ( 10 ), wherein the control device ( 90 ) Outputs, which are set up, the operating state of the internal combustion engine ( 10 ) and the torque absorption of the at least one unit ( 20 ), the control device ( 90 ) further comprises inputs arranged to receive a desired acceleration, characterized in that the control device ( 90 ) sets at a desired positive, negative or not to be provided acceleration an operating condition, the torque output of the internal combustion engine ( 10 ), which goes beyond the torque which corresponds to the desired acceleration, and for the control of the at least one unit ( 20 ) is set up such that the portion of the torque output of the internal combustion engine which exceeds the desired acceleration ( 10 ) at least partially from the at least one aggregate ( 20 ) is provided.