DE4344053B4 - Method for operating a hybrid vehicle and device for carrying out the method - Google Patents

Abstract

eingehalten wird, worin
N_F die Fahr- bzw. Vortriebsleistung des Verbrennungsmotors,
N_L die „überlagerte" Generatorleistung, d.h. die zum Antrieb der...Method for operating a hybrid vehicle having an internal combustion engine (6) and an electric machine (4) which can be operated as a motor that can be fed from a rechargeable electrochemical energy store (drive battery 7) or as a generator that can be driven by the internal combustion engine (6) and charges the energy store (7), wherein the propulsion of the hybrid vehicle either solely by the internal combustion engine (6), solely by the electric motor operated as a motor (4) or simultaneously by both takes place and wherein the internal combustion engine (6) during the propulsion of the vehicle at times simultaneously also operated as a generator electric machine (4) drives, characterized
that the combustion engine (6) in driving phases, in which its specific fuel consumption is high, then, when the electrochemical energy store (7) is at least partially discharged, additionally charged with the generator-operated electric machine (4),
and that the electric machine (4) is regulated in such a way that the relationship

is maintained, in which
N _F the driving or driving power of the internal combustion engine,
N _{L is} the "superimposed" generator power, ie the power to drive the ...

Description

The The invention relates to a method for operating a hybrid vehicle referred to in the preamble of claim 1 and a kind Device for performing of the procedure.

Hybrid vehicles in which the vehicle, if necessary, either alone by an internal combustion engine, in particular a gasoline or diesel engine, solely by one from a rechargeable electrochemical energy storage (battery) and for recharging the energy storage also regeneratively operable electric machine or simultaneously by the internal combustion engine and the Electric machine is driven, are known in many variations, including from the DE 21 33 485 A DE-29 43 554-A1, DE-29 45 303-C2 and DE-31 12 629-C2.

in the In general, such hybrid vehicles will operate in a lower performance or speed range and / or in an environment where it is low emissions, z. B. on city trips, only from the Electric machine driven and in the overlying Leistungsungs- or Speed ranges or for overland trips in general only from the combustion engine.

Generally it is known while the internal combustion engine operating phases of the hybrid drive on downgrades as well as when decelerating the vehicle to couple the electric machine - if they are not anyway constantly is coupled - and in the genera torbetrieb to control during these operating phases the charge or recharge electrochemical energy storage.

Basically, it is also known ( DE 21 33 485 A ), during internal combustion engine overland driving the electric machine - driven by the internal combustion engine - to operate as a generator and to charge the electrochemical energy storage. This mode of operation is therefore considered to be particularly advantageous because the internal combustion engine should then be loaded more uniformly on overland routes, which should lead to a substantial reduction in the exhaust emissions of the internal combustion engine. Considerations regarding the fuel consumption and the fuel optimization for the entire vehicle were not made. In the hybrid vehicles operated in this way, the power of the internal combustion engine should preferably be made larger than is necessary for normal overland travel, ie without a coupled generator, so as to charge the energy storage device when traveling overland, independently of the respective traction conditions or requirements can.

at Another known hybrid vehicle (DE-29 43 554-A1), which due to its special design not only by a high Regelspontanität, but also characterized by particularly low fuel consumption, it is also common the electric machine not only on downhill gradients and / or during deceleration phases the combustion engine driving - the electrochemical energy storage loading - regenerative but also if the energy content of the continuously monitored electrochemical energy storage during the electromotive itself Driving operation falls below a predetermined minimum value. In this Trap will happen the internal combustion engine automatically switched on and the electric machine from their motor operation Out and to charge the energy storage in the regenerative Operation reversed.

This continuous monitoring the energy content of the electrochemical energy storage and changing the Operating mode 'is mandatory in this known hybrid vehicle, because the electric machine here - apart from their generator function - not only as a prime mover for the vehicle is used, but in particular as a starting machine for the flywheel-trained engine is needed and therefore constantly must at least be sure that the engine operated Electric machine for starting the internal combustion engine from standstill out on the needed Minimum speed of the internal combustion engine can be accelerated.

at Hybrid vehicles, optionally by means of an electrochemical Energy storage powered electric motor or by an internal combustion engine It is specially designed for consumption optimization important that both Engines as possible each in a consumption at least comparatively Great Be operated, except in special Other cases Points of view, z. As the issue, priority will be given got to.

It is therefore already known (eg DE-31 12 629 C2) for the purpose of optimizing consumption of the burn tion motor to operate a hybrid vehicle such that in a lower power or speed range, only the electric machine and in a subsequent upper power or speed range, only the internal combustion engine is effective as a prime mover. This operating method is based on the knowledge that the specific fuel consumption of internal combustion engines, especially petrol or diesel engines in the lower part load range is particularly high and in the upper part load range - near full load - comparatively low and that in contrast electric machines in this lower part load range of the hybrid vehicle in particular with a comparatively good efficiency work when compared to the combustion engine, a comparatively small power of z. B. only 10 to 20% of the internal combustion engine. In this known hybrid vehicle (DE-31 12 629 C2), the switchover from the electric motor operated as a motor to the internal combustion engine for the purpose of further fuel consumption optimization at a power or speed value is now made, which changes depending on the expected still lying behind daily driving distance of the hybrid vehicle becomes.

Furthermore, the document discloses DE 41 13 386 C2 a hybrid drive assembly for motor vehicles, with an internal combustion engine, an auxiliary drive device, a device for branching off excess power of the internal combustion engine in one of the auxiliary drive means associated memory and with a higher-level control device for the operation of the internal combustion engine and / or the operating mode of the auxiliary drive device. Here, a design _{output is} determined by the intersection of a curve of the actual specific fuel consumption of the internal combustion engine and the permissible specific fuel consumption curve (b _ezul ), the latter curve being defined by the following formula:

Here are:
b _eEck the minimum specific _{power consumption} at the smallest driving speed of the internal combustion engine
η1 the efficiency for the conversion of the mechanical energy of the internal combustion engine in the storage energy
η2 the efficiency for the conversion of the storage energy into the energy of the auxiliary drive device
P the retrieved performance
P _corner the maximum power of the engine at minimum operating speed

there The design performance of the auxiliary drive device is chosen so that the specific power consumption for services below the Design performance in the operation of internal combustion engine and auxiliary drive device better is than when driven by the internal combustion engine alone.

In front In this background, the invention is based on the object, to provide a method of operating a hybrid vehicle, with the Help the overall consumption of the hybrid vehicle is further optimized.

These Task is in a method in the preamble of the claim 1 according to the invention by the characterizing features of claim 1 solved.

advantageous Embodiments and developments of the invention are specified in the subclaims.

Based an embodiment the invention will be described in more detail below explained.

In show the drawing

1 a hybrid vehicle with a series arrangement of internal combustion engine and electric machine,

2 the schematic representation of a control and regulating device for the hybrid vehicle,

3 a common engine map of an internal combustion engine and,

4 an (unusual) engine consumption map of an internal combustion engine.

In the embodiment according to 1 a hybrid vehicle is shown, as it from its structure, for example, from the DE-OS 29 43 554 or from the magazine "Gute Fahrt" 1/90, page 8 is known. In this hybrid vehicle, the input shaft 1 a conventional automotive gearbox 2 via a first switchable disconnect clutch 3 with an optionally operable as an electric motor or as a generator electric machine 4 as well as a second switchable disconnect clutch 5 with an internal combustion engine 6 connected.

The hybrid vehicle can in a known manner as needed either alone by the electric motor operated as an electric motor 4 be driven, the first disconnect clutch 3 closed and the second disconnect clutch 5 is open, or alone by the internal combustion engine 6 , in which case both separating couplings 3 and 5 are closed and the electric motor or regenerative electric machine 4 as a flywheel with revolves. In this combustion engine operating phase, the electric machine could 4 but also (eg on gradients or during special acceleration phases) in principle additionally be used for the drive of the hybrid vehicle by being connected to the electrochemical energy storage 7 (Drive battery) is connected or controlled in their motor operation.

Each an internal combustion engine and an electric machine having hybrid vehicles are u. a. designed to be in the same vehicle after Need the specific advantages of an electric motor or to take advantage of an internal combustion engine, z. B. in special inner city Areas the emission-free and / or the low-noise of the electric motor and outside these areas, z. B. for overland trips o. Ä. That Capital, with the internal combustion engine also longer Distances without refueling and if it is the road conditions if necessary, even at higher speeds to be able to.

With the inventive method for operating a hybrid vehicle z. B. the in 1 shown type is optimized while maintaining the aforementioned fundamental operational opportunities and advantages of such a hybrid vehicle, the fuel consumption of the entire vehicle in previously unaccustomed manner, namely simply in that the internal combustion engine 6 in driving phases in which its specific fuel consumption is high, in a special way additionally with regenerative power for charging the on-board electrochemical energy store (traction battery) 7 is loaded so that it is operated as a result of the resulting increase in the torque demanded at one point of its consumption map with compared to previously decidedly lower specific fuel consumption.

The superimposed generator power N _{L of} the electric machine 4 is controlled so that the total fuel consumption of the engine 6 , based on the total distance traveled (internal combustion engine without and with superimposed generator power and electric motor) is lower than the fuel consumption required for the same route with a pure internal combustion engine (ie without superimposed regenerative power) operation.

The total fuel consumption is thus composed of the fuel consumption for the internal combustion engine operated propulsion of the hybrid vehicle and the fuel consumption for driving the generator-operated electric machine 4 , The electrical energy generated thereby initially in the electrochemical energy storage 7 stored and made available in a later driving phase again for the electromotive propulsion of the hybrid vehicle.

In cases where the electrochemical energy storage 7 at this time still at least approximately fully charged, so z. B. still has about 70% of its load capacity, the internal combustion engine 6 on the other hand simply switched off and the propulsion of the hybrid vehicle alone by the then from the electrochemical energy storage 7 powered electric motor driven electric machine 4 causes, and so long until the operating conditions of the hybrid vehicle have changed so that the internal combustion engine 6 as a single drive could be operated again in more fuel-efficient higher load ranges, or so long until the electrochemical energy storage 7 As far as it is discharged that it is cheaper again, the hybrid vehicle in the aforementioned manner by the internal combustion engine 6 to drive and at the same time the energy storage 7 by the generator working electric machine 4 reload.

Insofar as a hybrid vehicle type is present, in which the electric machine or its rotating part deviates during combustion engine operation of the hybrid vehicle 1 is not always mechanically coupled to the internal combustion engine anyway, it is of course necessary to first mechanically couple the electric machine with the engine before they charge for charging the electrochemical En energy storage is controlled in the generator mode.

Ultimately it is by the method according to the invention advantageously possible to use the fuel so that the fuel consumption of the Hybrid vehicle is lower than in a conventional, d. H. purely internal combustion engine powered vehicle.

It understood in this context, that in this case the efficiency chain for the electrical energy conversion and the electromotive propulsion of the hybrid vehicle is of particular importance.

In the in 3 Exemplary illustrated typical engine map of an internal combustion engine are shown as a function of speed in addition to the thick solid full load curve and three thinly drawn hyperbolic torque curves for three different gears of the hybrid vehicle dashed three medium-pressure characteristics for three different constant engine power and also several lines each with constant specific fuel consumption. Although this map has of course been created using a specific internal combustion engine, it applies apart from the absolute sizes tend to be for all gasoline and diesel engines.

Out This engine map is easily recognizable that the specific fuel consumption an internal combustion engine in the unte ren partial load areas strong increases.

For the explanation the invention is assumed that a hybrid vehicle about the Golf class exists with an electric machine with a rated power equipped by only about 6 kW is.

If such a hybrid vehicle according to the currently prevailing operating conditions of the internal combustion engine 6 z. B. at about 2000 min ^-1 with a propulsive power N _F of about 6 kW is driven, in the example assumed so it runs at about 50 km / h, then works the internal combustion engine 6 in a comparatively low consumption lower part load range with a specific fuel consumption b _e of about 360 g / kWh, as can be seen from the engine map of 3 can be seen.

When in this combustion engine phase of the hybrid vehicle, the electric machine 4 is controlled according to the invention in its generator mode to the electrochemical energy storage 7 recharge, then the internal combustion engine 6 Instead of the previously required for the pure propulsion of the hybrid vehicle only 6 kW power N _F now a higher total power N _F + N _L , z. B. 8 kW, namely the power N _F for the propulsion of the hybrid vehicle and additionally the superimposed generator power N _L for driving the generator operating as an electric machine 4 , For the internal combustion engine 6 then results in the gross engine power N _F + N _L of 8 kW at 2000 min ^-1 a specific fuel consumption b _e 'of about 305 g / kWh. In 3 the corresponding mean-pressure curve at constant engine power of 8 kW is not shown further, but it is approximately in the lower third between the medium-pressure curve for 6 kW and 11 kW.

While in the pure combustion engine propulsion with the engine power N _F of 6 kW so a fuel consumption per hour of 6 × 360 g = 2160 g of fuel is present, the fuel consumption of the engine 6 with simultaneous drive of the generator powered by 2 kW electric machine 4 a total of 8 × 305 g = 2,440 g of fuel per hour. The additional consumption due to the 2 kW generator power (charging power N _L ) is thus 280 g of fuel. The specific generator power consumption, ie the additional consumption per kilowatt-hour generated, is therefore 140 g / kWh.

For the evaluation of the fuel consumption of the entire vehicle, it is of course not only interesting and important, which specific fuel consumption must be spent to generate a kilowatt-hour of generator power, but also how much of it in the electromotive operation of the electric machine 4 can be used again as a drive power for the vehicle. A key role therefore plays the efficiency chain of the electrical function chain, ie the overall efficiency η _ges of electrical energy generation, storage and conversion into drive energy. The following individual efficiencies can be assumed today on the basis of modern components:

für den rein elektromotorischen Vortrieb des Hybridfahrzeugs, d. h. wenn diese generatorisch erzeugte und im Energiespeicher 7 gespeicherte Energie später von der für den Vortrieb des Hybridfahrzeugs elektromotorisch betriebenen Elektromaschine 4 dem Energiespeicher 7 wieder entnommen wird.A specific generator power consumption according to the above example of z. B. 140 g / kWh, ie the specific fuel consumption of the engine 6 to generate a kilowatt-hour of generator power, thus resulting in an equivalent specific fuel consumption of

for the purely electromotive propulsion of the hybrid vehicle, that is, when this generator generated and in the energy storage 7 stored energy later from the electromotive for the propulsion of the hybrid vehicle electric machine 4 the energy storage 7 is removed again.

erfüllt wird.In order to obtain a positive energy balance, thus the generator power (charging power N _L ) must be controlled so that the condition

is fulfilled.

If this condition is not met, the superposition of regenerative power (N _L ) would lead to a specific fuel consumption for the (later) pure electromotive propulsion, which is at least as great as for the purely internal combustion engine propulsion. In this case, it would therefore not make sense to burden the internal combustion engine with additional generator power; It would then be better, despite the per se bad specific fuel consumption to continue purely internal combustion engine.

It is readily apparent that, in addition to the choice of the operating point of the internal combustion engine, this type of overall fuel consumption optimization of the hybrid vehicle 6 and the choice of the controlled or adjusted generator power (charging power N _L ) of the electric machine 4 the efficiency chain, ie the overall efficiency η _{ges is} of particular importance. The better the overall efficiency for the electrical energy conversion, etc., the more fuel can be saved in this way.

With a hybrid vehicle can thus in certain use profiles of the vehicle, so if it comparatively often in fuel-efficient lower part load ranges of the engine 6 should be operated when using the operating method of the invention even compared to purely internal combustion engine driven vehicles fuel saved.

With preference the electric machine 4 regulated such that the superimposed generator power N _L is defined well limited to a value at which with the propulsive power N _F and in addition to the drive of the generator-operated electric machine 4 loaded internal combustion engine 6 achieves a specific fuel consumption b _e 'that is at least close to its specific fuel consumption minimum.

This can be achieved with little effort in terms of control technology simple way that the electric machine 4 is controlled or regulated so that the relationship N _L = K × n - N _{F is} satisfied, wherein n is the engine speed and K is a the stroke volume H of the engine proportional and under Zuhil Determining the engine fuel consumption map identifiable and definable characteristic constant of the internal combustion engine 6 is.

This is based on the in 4 illustrated map explained in more detail.

Deviating from the usual representation of engine maps is in 4 the effective average combustion pressure P _{e is shown} as a function of the specific fuel consumption b _{e of} the internal combustion engine, with different engine speeds n as parameters.

It has been shown that in such a representation of both petrol and diesel engines, regardless of their number of cylinders, a field of closely juxtaposed, approximately hyperbolic curves results, so that it is sufficient for the present purpose, this characteristic field by a medium hyperbolic Characteristic to be replaced mathematically by the equation P e = k × b e l where k and l are each characteristic constants for each type of engine present.

This in 4 shown engine consumption map has of course been created using a specific internal combustion engine, namely a 6-cylinder gasoline engine with a displacement of 2.8 l.

As it turned out, however, this engine fuel economy map, apart from the absolute figures, tends to apply to all petrol and diesel engines. Thus, for each type of internal combustion engine, an engine fuel consumption map P _e = k × b _e ^l can be created whose characteristic constants k and l can, of course, differ somewhat from one engine type to another.

zunächst kontinuierlich ab. Im oberen Druckbereich oberhalb eines mit P*_e bezeichneten mittleren effektiven Verbrennungsdrucks ändert sich dann der spezifische Kraftstoffverbrauch b_e nicht mehr nennenswert. Der zu diesem mittleren effektiven Verbrennungsdruck gehörige spezifische Kraftstoffverbrauch ist mit b_e* gekennzeichnet.As 4 reveals the specific fuel consumption b _e with increasing mean effective combustion pressure P _e , ie, with increasing engine power

initially continuously. In the upper pressure range above a mean effective combustion pressure, designated P * _e , the specific fuel consumption b _{e then} no longer appreciably changes. The specific fuel consumption associated with this mean effective combustion pressure is indicated by b _e *.

To illustrate the invention are in 4 only by way of example two different operating cases arbitrarily indicated. On the one hand, it was assumed that the vehicle would be moved at a driving speed of about 50 km / h (in the example engine used in the 5th gear at a speed n = 1095 min ^-1 ) pure combustion engine. For this propulsion, the internal combustion engine must apply a power N _F (50) = 4 kW, where it has a comparatively high specific fuel consumption b _e (50). If during this driving phase the internal combustion engine 6 now in addition to the drive of the generator-operated electric machine 4 is used and z. B. a superimposed generator power N _{L is} also controlled by 4 kW, then the internal combustion engine 6 Apply a total power N _F + N _L = 8 kW, working with a much lower specific fuel consumption b ' _e (50). Similarly, it was assumed that the hybrid vehicle in the 5th gear at about 70 km / h (with a speed n = 1570 min ^-1 ) is moved purely by internal combustion engine, including the internal combustion engine 6 must apply a power N _F (70) = 7.2 kW. This results in a specific fuel consumption b _e (70). For this example, it was assumed that the internal combustion engine is alternatively additionally loaded with a superimposed generator power N _L = 6 kW, that is to say a total power N _F + N _L = 13.2 kW must be applied. As can be seen, this also results in a significant reduction in specific fuel consumption to b ' _e (70).

It is based on the in 4 illustrated engine consumption map easily understand that an optimal total consumption of the hybrid vehicle is achieved when during hybrid operation of the internal combustion engine 6 in appropriate situations, in each case in addition to the power serving for propulsion N _F just about such a superimposed generator power is applied that he works in about straight with the mean effective pressure P * _e , when exceeding the specific fuel consumption b ' _e no longer would significantly reduce.

beträgt.Optimum fuel consumption during the hybrid driving operation thus results when the generator-operated electric machine is controlled such that the superimposed generator power N _L just about

is.

Since the stroke volume H and this average effective combustion pressure P * _e to be determined and determined from the engine consumption map P _e = f (b _e ) represent characteristic constant quantities known for each engine type, this relationship can also be represented as N L = K × n - N F . where K is a constant characteristic of the respective engine type.

Due to the well-defined limitation of the superimposed generator power N _L to such a value at which the internal combustion engine 6 just about works with the average effective combustion pressure P * _e , it is achieved that on the one hand the specific fuel consumption for the acted upon by the traction power N _F and the superimposed generator power engine is kept as low as possible during this time and on the other hand, that the propulsion of the Vehicle occupying internal combustion engine 6 as long as possible with the low specific fuel consumption b * _e associated with this combustion pressure P * _e .

Without this limitation of the superimposed generator power N _L , the internal combustion engine would then be operated with this low specific fuel consumption or a slightly lower during this operating phase, but only for a possibly much shorter operating time, as a - not limited - higher superimposed generator power the electrochemical energy storage 7 Of course, charging would be unnecessarily faster than the generator power limited in the aforementioned manner.

As already mentioned, a hybrid vehicle can basically be operated as needed in three different operating modes. Pure electric motor, if it depends on emission-free and / or low noise in special applications, purely internal combustion engine, if it is z. B. at longer cross-country journeys to higher speeds and ultimately hybrid in the context of the present invention, ie that is automatically switched according to the prevailing driving and operating conditions and the specifications of the driver automatically in the for the overall consumption of the vehicle most favorable operation, which at times a purely electromotive propulsion, a purely internal combustion engine propulsion or an internal combustion engine propulsion with superimposed generator power can be. Whether one mode of operation or the other mode of operation automatically occurs depends, inter alia, on the state of charge of the electrochemical energy store 7 and also on whether the specific fuel consumption b _{e of} the internal combustion engine 6 in the current operating state with purely internal combustion engine propulsion greater than in 4 b * ₂ , specific fuel consumption associated with P * _e would be equal or, if necessary, slightly lower.

Therefore, a control device required for the operation according to the invention of a hybrid vehicle must, inter alia, also have the state of charge of the electrochemical energy store 7 have monitoring and the actual electronic control and regulating device of the vehicle signaling charging control device and a device for determining the instantaneous specific fuel consumption b _{e of} the internal combustion engine 6 and comparing this instantaneous specific fuel consumption with the aforementioned specific fuel consumption b * _e , which is a known constant characteristic of each type of engine. Such a device for determining and comparing the instantaneous specific fuel consumption b _e contains customary electronic logic and comparison components as well as electronic memory devices in which, in addition to characteristic vehicle constants, the engine characteristic field also corresponds in the usual way 3 and / or the engine consumption map accordingly 4 of the internal combustion engine 6 are stored.

• A. Die Kapazität des elektrochemischen Energiespeichers 7 entspricht zumindest annähernd seiner Nennkapazität K_Ahist ≥ ~ 0,7 × K_Ahnenn: Bei praktisch vollgeladenem Energiespeicher würde dem Verbrennungsmotor 6 generell keine Generatorleistung überlagert werden. Je nach vorliegender Betriebsbedingung würde ein rein elektromotorischer Vortrieb, ein rein verbrennungsmotorischer Vortrieb oder aber ein gemischter Vortrieb, d. h. ein gleichzeitiger Antrieb durch Verbrennungsmotor und Elektromotor eingestellt werden. Wenn sich bei der vorliegenden Betriebssituation für einen rein verbrennungsmotorischen Vortrieb ein spezifischer Kraftstoffverbrauch b_e ergeben würde, der größer, also ungünstiger als der vorerwähnte spezifische Kraftstoffverbrauch b*_e ist, dann würde für den Fall, daß die Leistung der vergleichsweise kleinen Elektromaschine 4 für den Vortrieb ausreicht rein elektromotorisch gefahren werden, jedoch für den Fall, daß eine höhere Vortriebsleistung erforderlich ist, rein verbrennungsmotorisch. Wenn sich dagegen bei der vorliegenden Betriebssituation bei rein verbrennungsmotorischem Vortrieb ein spezifischer Kraftstoffverbrauch b_e ergeben würde, der gleich oder möglicherweise sogar geringfügig kleiner ist als der vorerwähnte spezifische Kraftstoffverbrauch b*_e, dann wäre ein gemischter Antrieb sinnvoll, d. h. ein Antrieb durch den Verbrennungsmotor 6 und zusätzlich durch die Elektromaschine 4; durch den (Teil)Antrieb durch die Elektromaschine 4 würde der elektrochemische Energiespeicher 7 nämlich wieder zum Teil entladen werden, wodurch wieder die Voraussetzung geschaffen wird, bei entsprechender Betriebssituation verbrauchsoptimierend mit überlagerter Generatorleistung zu fahren.
• B. Die Kapazität des elektrochemischen Energiespeichers 7 ist erheblich niedriger als ihre Nennkapazität K_Ahist < ~ 0,7 K_Ahnenn: Bei teilentladenem elektrochemischen Energiespeicher 7 wird je nach Betriebssituation entweder rein verbrennungsmotorisch oder aber verbrennungsmotorisch mit überlagerter Generatorleistung gefahren, je nach dem was in dieser Situation für den Gesamtverbrauch des Hybridfahrzeugs günstiger ist. Wenn der spezifische Kraftstoffverbrauch b_e bei rein verbrennungsmotorischen Betrieb gleich oder aber sogar geringfügig niedriger als der vorerwähnte spezifische Kraftstoffverbrauch b*_e ist, dann wird dem Verbrennungsmotor 6 lediglich die Traktionsleistung abverlangt, d. h. N_V = N_F worin N_V die vom Verbrennungsmotor aufzubringende Gesamtleistung darstellt und N_F wie bereits zuvor ausgeführt die vom Verbrennungsmotor für den Vortrieb des Fahrzeugs zur Verfügung zu stellende Leistung. Wenn sich jedoch bei rein verbrennungsmotorischem Betrieb ein spezifischer Kraftstoffverbrauch b_e ergeben würde, der größer als der vorerwähnte spezifische Kraftstoffverbrauch b*_e ist, dann würde der Verbrennungsmotor 6 zusätzlich die in den Generatorbetrieb gesteuerte Elektromaschine 4 antreiben, wobei dann die überlagerte Generatorleistung N_L in zuvor beschriebener Weise gesteuert bzw. geregelt wird. Eine für die in diesem Sinne automatische Aussteuerung der überlagerten Generatorleistung N_L geeignete elektronische Steuer- und Regeleinrichtung, die Teil einer für den Betrieb des Hybridfahrzeugs vorgesehenen Gesamtregeleinrichtung ist, ist in 2 prinzipienhaft dargestellt. Diese Steuer- und Regeleinrichtung wird durch eine elektronische Logikbausteine bzw. Logikstufen enthaltende Hybridsteuereinheit 12 gebildet, bei der es sich z. B. um einen bekannten Mikroprozessor handeln kann. Diese Hybridsteuereinheit 12 enthält im Ausführungsbeispiel im wesentlichen als Kern einen Rechenbaustein 13, zwei Vergleichsglieder 14, 15 und ein Addierglied 16.

With the help of the means for determining and comparing the instantaneous specific fuel consumption b _{e is} the electronic control device would during hybridischen mode according to the different conditions ready for operation automatically select the following modes:

• A. The capacity of the electrochemical energy store 7 corresponds at least approximately to its nominal capacity K _Ahist ≥ ~ 0.7 × K _Ancestors : With virtually fully charged energy storage would the internal combustion engine 6 generally no generator power are superimposed. Depending on the existing operating condition, a purely electromotive propulsion, a purely internal combustion engine propulsion or a mixed propulsion, ie a simultaneous drive by internal combustion engine and electric motor would be set. If in the present operating situation for a purely internal combustion engine propulsion specific fuel consumption b _e would result, which is greater, that is unfavorable than the aforementioned specific fuel consumption b * _e , then in the event that the performance of the comparatively small electric machine 4 sufficient for the drive sufficient to be driven by an electric motor, but in the event that a higher propulsive power is required, purely internal combustion engine. If, on the other hand, a specific fuel consumption b _e would result in the present operating situation with purely internal combustion engine propulsion, which is equal to or possibly even slightly smaller than the abovementioned specific fuel consumption b * _e , then a mixed drive would be meaningful, ie a drive by the internal combustion engine 6 and additionally by the electric machine 4 ; through the (partial) drive through the electric machine 4 would the electrochemical energy storage 7 namely again be partially discharged, which again the condition is created to drive in a corresponding operating situation consumption optimized with superimposed generator power.
• B. The capacity of the electrochemical energy store 7 is considerably lower than its rated capacity K _Ahist <~ 0.7 K _Ancestors : With partially _discharged electrochemical energy storage 7 Depending on the operating situation, either purely internal combustion engine or internal combustion engine driven with superimposed generator power, depending on what is cheaper in this situation for the total consumption of the hybrid vehicle. If the specific fuel consumption b _e in pure internal combustion engine operation is equal to or even slightly lower than the aforementioned specific fuel consumption b * _e, then the internal combustion engine 6 demanded only the traction power, ie N _V = N _F where N _V represents the total power to be applied by the engine and N _F as already stated before the power to be provided by the internal combustion engine for the propulsion of the vehicle. However, if in pure-engine operation, a specific fuel consumption b _e greater than the aforementioned specific fuel consumption b * _e would result, then the engine would become 6 in addition, the electric machine controlled in the generator mode 4 drive, in which case the superimposed generator power N _{L is} controlled or regulated in the manner described above. An electronic control and regulating device which is suitable for the automatic control of the superimposed generator power N _L in this sense and which is part of an overall control device provided for the operation of the hybrid vehicle is disclosed in US Pat 2 presented in a principled way. This control and regulating device is by a hybrid logic unit containing electronic logic modules or logic stages 12 formed, in which it is z. B. may be a known microprocessor. This hybrid control unit 12 contains in the embodiment essentially as a core a computing block 13 , two comparators 14 . 15 and an adder 16 ,

Through the calculation block 13 is during the driving phase in which the internal combustion engine 6 not only with the required for the propulsion of the vehicle power N _F , but additionally with a superimposed generator power N _L for driving the controlled in the generator mode electric machine 4 is acted upon, on the one hand a control and regulating signal M _L for the desired optimum modulation of the electric machine 4 and on the other hand, a control and regulating signal for the corresponding modulation of the internal combustion engine 6 generated.

erfüllt wird.By the relationship M _L = K * × P * _e - M _F (n) is symbolized that the computing block 13 generates an output or control signal M _L , through which the electric machine 4 and the internal combustion engine 6 be controlled or regulated such that for the superimposed generator power N _L as desired, the previously explained relationship

is fulfilled.

As in practice usually not the power, but ultimately the moment of the two machines 6 . 4 is controlled or regulated, not the power relationship, but the corresponding torque relationship is entered in the computing block.

da ja K*, P*_e und k, l und b*_e jeweils für jeden Motortyp charakteristische bekannte Konstanten sind.The registered torque relationship was written using the mean effective combustion pressure P * _e , because previously described with reference to 4 explained explanations of the invention in particular to this value. But just as well, this moment relationship can also be formulated using the specific fuel consumption b * _{e associated} with P * _e

since K *, P * _e and k, l and b * _e are characteristic constants characteristic of each type of motor.

That of the calculation block 13 thus generated control and regulating signal M _L causes via an only schematically indicated electronic actuator 11 the corresponding modulation or control of the generator-operated electric machine 4 , wherein it is indicated that the from the computing block 13 predetermined setpoint M _L in the comparison element 14 with the corresponding actual value of the electric machine supplied there 4 is compared. The resulting deviation is designated M ' _E.

As the internal combustion engine 6 In this phase of operation with superimposed generator power, not only the power N _F required for propulsion of the vehicle, or the motor torque M _F (n) required to compensate for the driving resistances, must be generated by the hybrid control unit 12 At the same time, it is also ensured that the internal combustion engine is operated with a correspondingly higher overall output N _V = N _F + N _L or generates a correspondingly higher total torque M _F (n) + M _L , although the driver controls the gas or accelerator pedal 8th in fact only has operated so far that the internal combustion engine is operated with a required to reach and maintain the desired driving speed power N _F or generates only a correspondingly large moment for the propulsion M _F (n).

In an adder 16 the hybrid control unit 12 is therefore one for this modulation of the internal combustion engine 6 Required setpoint M _F (n) + M _L generated, which also has only indicated by an electronic actuator 10 the internal combustion engine 6 as required, this setpoint M _F (n) + M _L in turn in a comparison element 15 is compared with a corresponding actual value M _{V of} the internal combustion engine. The resulting deviation is designated M '(v).

With 9 is still an electronic logic modules or logic levels containing electronic mode switch indicated, according to the previously explained criteria on the basis of stored maps and supplied operating parameters automatically each for the respective operating state consumption-optimal mode of operation, namely purely electric motor propulsion, pure internal combustion engine propulsion or internal combustion engine propulsion superimposed generator power turns on.

Only in internal combustion engine propulsion with superimposed generator power is the hybrid control unit 12 activated.

As in 2 is indicated, however, is the electronic mode switch 9 in pure electromotive propulsion of the actuator 11 the electric machine 4 and with purely internal combustion engine propulsion to the actuator 10 of the internal combustion engine 6 each directly fed a control signal to the electric machine 4 or the internal combustion engine 6 according to the driver by pressing the accelerator or accelerator pedal 8th expressed desire to auszusteuern.

1

input shaft of the vehicle gearbox

2

Car change gear

3

first switchable disconnect clutch

4

electric machine

5

second switchable disconnect clutch

6

internal combustion engine

7

electrochemical Energy storage (drive battery)

8th

accelerator

9

electronic Mode switch

10

actuator for the internal combustion engine

11

actuator for the electric machine

12

Hybrid control unit z. B. microprocessor

13

computing chip

14

comparator

15

comparator

16

adder

NF

driving or propulsive power of the internal combustion engine

NL

"superimposed" generator power, d. H. the for the

generator drive applied power of combustion

motors

b _e

specific Fuel consumption of the internal combustion engine

at pure propulsion

b _e '

specific Fuel consumption of the internal combustion engine

at additional Drive of regeneratively operated

electric machine

b _e *

one on the basis of the engine consumption map

specified specific value of the specific fuel

consumption

η _ges

Overall efficiency for the electrical energy production,

-storage and reconversion in drive energy

Claims (5)

Method for operating a hybrid vehicle with an internal combustion engine ( 6 ) and an electric machine ( 4 ), which as a rechargeable electrochemical energy storage (drive battery 7 ) or as an internal combustion engine ( 6 ) drivable, the energy storage ( 7 ) is driving, the propulsion of the hybrid vehicle either alone by the internal combustion engine ( 6 ), solely by the electric motor operated as a motor ( 4 ) or at the same time by both and whereby the internal combustion engine ( 6 ) during the propulsion of the vehicle at times simultaneously also operated as a generator electric machine ( 4 ), characterized in that the internal combustion engine ( 6 ) in driving phases in which its specific fuel consumption is high, when the electrochemical energy store ( 7 ) is at least partially discharged, in addition to the generator-operated electric machine ( 4 ) and that the electric machine ( 4 ) is regulated in such a way that the relationship

is maintained, wherein N _F driving or propulsion power of the engine, N _L the "superimposed" generator power, ie the power to drive the electric machine operated as a generator additionally applied power of the engine, η _ges the overall efficiency of electrical energy production, storage and reconversion in drive energy, b _e the specific fuel consumption of the internal combustion engine with pure propulsion, ie without additional generator load and b _e 'the specific fuel consumption of additionally loaded with the generator drive Verbrennungsmo gate mean. Method according to claim 1, characterized in that the electric machine ( 4 ) is regulated such that the superimposed generator power N _{L is} limited to a value at which the with the propulsive power N _F and in addition to the drive of the regenerative electric machine ( 4 ) loaded internal combustion engine ( 6 ) reaches a specific fuel consumption (b _e ') which is at least near its specific fuel consumption minimum. Method according to claim 2, characterized in that the electric machine ( 4 ) is regulated in such a way that the relationship N L = K · n - N F is satisfied, wherein N _{L is} the superimposed generator power N _F driving or propulsion power of the engine, n is the engine speed and K is a the stroke volume of the engine proportional as well as on the basis of the engine fuel consumption map determined and definable characteristic constant of the engine. Method according to one of claims 1 to 3, characterized that the internal combustion engine is a gasoline or diesel engine. Device for carrying out the method according to claims 1 to 4, comprising a state of charge of the electrochemical energy store ( 7 ) monitoring charging control device, an electronic storage device for storing the engine map and the engine consumption map and characteristic vehicle data, a device containing electronic logic and computing devices for determining the instantaneous specific fuel consumption b _{e of} the non-regenerative combustion engine ( 6 ) and comparing this value with a fuel-efficient specific fuel consumption b * _e determined or determined on the basis of the stored engine fuel consumption map P _e = f (b _e ), an electronic operating mode switch ( 9 ) based on the comparison of the instantaneous specific fuel consumption b _e with the specified fuel consumption specific fuel consumption b * _e and the charge state of the electrochemical energy storage device determined by the charge control device ( 7 ) automatically in the present operating state for the total consumption respectively most favorable mode of operation of the hybrid vehicle, ie the purely electromotive propulsion, the pure internal combustion engine propulsion or internal combustion engine propulsion with superimposed generator power N _L selects an electronic computing modules ( 13 ), Comparison members ( 14 . 15 ) and adders ( 16 ) hybrid control unit ( 12 ), which, during the operation of the electronic mode switch ( 9 ) selected hybrid mode with internal combustion engine propulsion and superimposed generator power N _L on the one hand in accordance with a in the computing module ( 13 ) stored torque relationship M _L = K * · P * _e - M _F (n) or a corresponding power relationship tuned to the current driving condition and the desired optimal total consumption target value M _L for controlling and regulating the electric machine ( 4 ) and, on the other hand, a setpoint value M _L + M _F (n) for the internal combustion engine ( 6 ) generated.