DE102012025001A1 - Method and device for starting an internal combustion engine - Google Patents

Abstract

The invention relates to a device (1) and a method for starting an internal combustion engine (2), wherein a crankshaft (3) is coupled in a torsionally flexible manner to a rotor (6) of a starter motor (4), the starter motor (4) being engaged in a starting process Starting torque (AM) is generated, which is transmitted to the crankshaft (3) via the torsionally flexible coupling, a negative or positive starting torque (AM) being generated at a starting point in the starting process, with at least one sign change of the starting torque (AM) taking place during the starting process , wherein a rotation of the crankshaft (3) is mechanically blocked before or at the start time, the rotation of the crankshaft (3) being released if or after an energy stored in a torsional vibration system has a maximum permissible energy or that for starting the internal combustion engine (2) necessary energy is achieved, the torsional vibration system at least from the torsionally flexible coupling and the rotor (6) of the starter motor (4).

Description

The invention relates to a method and a device for starting an internal combustion engine.

The DE 10 2009 033 544 A1 discloses a method for starting an internal combustion engine of a motor vehicle, wherein the internal combustion engine exerts a drive torque in a preferred direction of the internal combustion engine to a crankshaft. A starter motor applies a starting torque to the crankshaft in a starting operation to achieve a minimum speed of the internal combustion engine, with a control unit controlling the starting torque. Here, the control unit in the starting process controls the starting torque time-dependent between a positive maximum starting torque and a negative minimum starting torque, with a positive starting torque in the direction and a negative starting torque against the preferred direction acts on the crankshaft.

• 1. Das einzige rotierende Element des Anlassmotors, nämlich der Rotor, kann eine Sekundärmasse eines Zweimassenschwungrades (ZMS) ersetzen. Hierdurch kann sich für das mechanische Gesamtsystem aus Kurbelwelle und Anlassvorrichtung ein kleineres Trägheitsmoment ergeben, welches wiederum höhere Drehzahlgradienten bei Drehzahl-Änderungen erlaubt und somit eine höhere Dynamik im Betrieb des Kraftfahrzeugs ermöglicht.
• 2. Durch geeignete Ansteuerung des Anlassmotors können Dreh-Ungleichförmigkeiten der Kurbelwelle vollständig oder teilweise kompensiert werden. Die Anordnung erlaubt somit eine aktive Schwingungstilgung oder -dämpfung.
• 3. Da zur Ansteuerung des Anlassmotors in der Regel ein elektrischer Rotorwinkel erforderlich ist, kann dieser mit wenig mehr Aufwand in einen mechanischen Rotorwinkel umgerechnet werden. Ist auch ein Kurbelwellenwinkel bekannt, so kann aus der Differenz zwischen dem Kurbelwellenwinkel und dem mechanischen Rotorwinkel ein Verdrehwinkel eines elastischen Kopplungselements, beispielsweise einer Drehfeder, bestimmt werden. In Abhängigkeit dieses Verdrehwinkels kann ein aktuell übertragenes Drehmoment zwischen Rotor und Kurbelwelle bestimmt werden. Somit ergibt sich vorteilhaft, dass keine direkte Messung des Drehmoments erforderlich ist.
• 4. Ist, wie vorhergehend erläutert, der Drehwinkel bekannt, so kann in Abhängigkeit des Drehwinkels eine verbesserte Lastwechselregelung erfolgen, bei der trotz des sich elastisch verhaltenen Triebstrangs schnelle und komfortable Laständerungen ausgeregelt werden können.
• 5. In Abhängigkeit des Drehwinkels kann ebenfalls eine Regelung des Anlassvorgangs derart erfolgen, dass ein maximaler Betrag des Verdrehwinkels nicht überschritten wird. Hierdurch kann z. B. eine mechanische Beanspruchung von Endanschlägen verhindert werden. Als Stellgröße für eine solche Regelung kann beispielsweise das von dem Anlassmotor erzeugte Anlassmoment, das von der Verbrennungskraftmaschine erzeugte Moment oder, bei einem Automatikgetriebe, eine Kupplungskapazität als Stellgröße verwendet werden.
• 6. Es fällt bei einer solchen Triebstrang-Anordnung kein Verschleiß von z. B. Riemen an.
• 7. Weiter werden in einer solchen Anordnung keine Riemen-Verluste erzeugt.

The document also discloses a drive train arrangement in which the rotor of the electric motor designed as a starter motor is rotationally connected to the crankshaft of the internal combustion engine. Such an arrangement offers a number of advantages:

• 1. The only rotating element of the starter motor, namely the rotor, can replace a secondary mass of a dual mass flywheel (DMF). This can result in a smaller moment of inertia for the overall mechanical system comprising the crankshaft and the starting device, which in turn permits higher rotational speed gradients with changes in rotational speed and thus allows greater dynamics in the operation of the motor vehicle.
• 2. By suitable control of the starter motor rotational non-uniformities of the crankshaft can be fully or partially compensated. The arrangement thus allows active vibration damping or damping.
• 3. Since an electric rotor angle is usually required to control the starter motor, it can be converted into a mechanical rotor angle with little effort. If a crankshaft angle is also known, a twist angle of an elastic coupling element, for example a torsion spring, can be determined from the difference between the crankshaft angle and the mechanical rotor angle. Depending on this angle of rotation, a currently transmitted torque between the rotor and the crankshaft can be determined. Thus, it is advantageous that no direct measurement of the torque is required.
• 4. Is, as previously explained, the rotation angle known, it can be done depending on the angle of rotation an improved load change control, in spite of the elastically behaved drive train fast and comfortable load changes can be compensated.
• 5. Depending on the angle of rotation can also be a control of the starting process done in such a way that a maximum amount of the rotation angle is not exceeded. As a result, z. B. a mechanical stress on end stops can be prevented. As a control variable for such a control, for example, the starting torque generated by the starter motor, the torque generated by the internal combustion engine or, in an automatic transmission, a clutch capacity can be used as a control variable.
• 6. It falls in such a drive train arrangement no wear of z. B. belts.
• 7. Further, no belt losses are generated in such an arrangement.

A disadvantage of such an arrangement, however, is that in particular for the cold start of the internal combustion engine high torques must be generated by the starter motor, especially when there is no torque ratio between the crankshaft and the rotor.

Will that be in the DE 10 2009 033 544 A1 As applied to methods disclosed in such a drive train arrangement, the crankshaft of the internal combustion engine will move even before reaching a maximum allowable angle of rotation of the torsionally flexible coupling element, ie resonate. By in particular at low temperatures high friction torque of the crankshaft, including coupled to the crankshaft further components, eg. As the piston and the camshaft, the arrangement energy is withdrawn, which should be desirable for starting available. In particular, it may come to an equilibrium, in which the energy supplied by the starting torque corresponds to the discharged friction energy. In this case, starting the internal combustion engine would not be possible.

The DE 10 2012 201 102 A1 discloses a vehicle with an internal combustion engine and an electric machine, which is kinematically coupled to the internal combustion engine for starting the internal combustion engine and which is kinematically decoupled from the internal combustion engine during operation of the internal combustion engine. Furthermore, the vehicle comprises an energy recuperation and storage device, wherein the energy recuperation and storage device can be kinematically coupled to the internal combustion engine during the switching off or during the coasting of the internal combustion engine is and at least part of the kinetic energy stored in the engine at the moment of switching off the internal combustion engine and stores.

There is a technical problem to provide a method and apparatus for starting an internal combustion engine, which allow reliable starting of the internal combustion engine, wherein requirements can be reduced to a height of a maximum to be generated starting torque.

The solution of the technical problem results from the objects with the features of claims 1 and 10. Further advantageous embodiments of the invention will become apparent from the dependent claims.

It is a basic idea of the invention to prevent a crankshaft of the internal combustion engine from rotating until a rotary oscillator formed from the crankshaft, a rotor of the starter motor and a mechanically coupling elastic coupling element reaches a state in which a stored energy in the rotary oscillator, which is composed of a potential energy of the torsionally elastic coupling element and a kinetic energy of the rotor of the starter motor, sufficient to start the internal combustion engine. In particular, the stored energy in the rotary oscillator is sufficient to a z. B. to overcome by a static friction of the internal combustion engine required breakaway torque and compression and Gleitreibungsmomente the internal combustion engine.

Proposed is a method for starting an internal combustion engine, wherein a crankshaft is rotationally elastically coupled to a rotor of an electric machine, for example via an elastic coupling element. In a starting process, the starter motor generates a starting torque, which is transmitted via the torsionally flexible coupling to the crankshaft. The starter motor can be designed here as an electric machine.

At a starting time of the starting process, a negative or positive starting torque is generated. Here, a positive starting torque denotes a starting torque, which acts in a preferred direction of rotation of the crankshaft to the crankshaft. Correspondingly, a negative starting torque refers to a torque which acts counter to the preferred direction of rotation on the crankshaft. The preferred direction of rotation of the crankshaft corresponds to the direction of rotation of the crankshaft during operation of the internal combustion engine. Thus, the starting operation can begin either with a torque acting in the preferred direction of rotation or a torque acting counter to the preferred direction of rotation. During the starting process, at least one sign change of the starting torque takes place. Thus, after the start time, the starting engine is controlled in such a way that, following a negative starting torque at the starting time, a positive starting torque or, following a positive starting torque generated at the starting time, a negative starting torque is generated. Preferably, several sign changes of the starting torque occur during the starting process. This can also be described as a modulation of the starting torque. The modulation of the starting torque thus describes a control of the starting torque, the starting torque alternating between a positive starting torque and a negative starting torque. A change of sign of the starting torque can z. B. time-dependent, so after a predetermined period of time. Preferably, a sign change of the starting torque takes place at a time or shortly after a point in time at which a change of sign of the rotary movement of the rotor takes place.

In this case, a control device may be provided which regulates the starting torque according to the previously described modulation of the starting torque. In particular, the starting torque between a positive maximum starting torque and a negative minimum starting torque can be controlled, with only the positive maximum starting torque or the negative minimum starting torque is generated by the starter motor.

Corresponds to a sign of the starting torque always the sign of the rotational movement of the rotor of the starter motor, it is operated exclusively in a motor operating mode.

According to the invention, a rotation of the crankshaft is mechanically blocked before or at the start time. The mechanical blockage can in this case be carried out, for example, by a blocking agent. For example, rotation of the crankshaft with a crankshaft brake, i. H. be blocked by a frictional connection between the crankshaft and the blocking means. Alternatively, the crankshaft may be rotated by a crankshaft lock, i. H. a positive connection between the crankshaft and the blocking means to be blocked.

The rotation of the crankshaft is released again when or after energy stored in a torsional vibration system reaches a maximum allowable energy or energy necessary to start the internal combustion engine. Thus, the rotation of the crankshaft can be released precisely at the time when the energy stored in the torsional vibration system reaches the maximum permissible energy or the energy required to start the internal combustion engine. Alternatively, the rotation of the crankshaft can be released in time after the time at which the energy stored in the torsional vibration system has reached the maximum allowable energy or the energy required to start the internal combustion engine. The time difference between reaching the maximum or necessary energy and the release, for example, be a predetermined period of time, for. B. a period of time that is needed to achieve a desired phase of the torsional vibration.

When the crankshaft is blocked, the torsionally flexible coupling and the rotor of the starter motor and optionally further parts mechanically connected to the rotor form a torsional vibration system or a so-called rotary oscillator. During the starting process, potential energy stored in torsionally elastic coupling is converted into kinetic energy of the rotor of the starter motor and vice versa. Thus, in each period between two similar sign changes of the rotor speed, there are two times when the potential energy is maximum and the kinetic energy is zero, and two times when the potential energy is zero and the kinetic energy is maximum. During cranking, when the crankshaft is locked, the energy stored in the torsional vibration system will increase because the energy supplied by the starter motor is greater than the energy essentially dissipated by friction.

The energy required to start the internal combustion engine may be less than the maximum allowable energy. The maximum allowable energy may, for. B. be a potential energy in a state amount maximum torsions, in the corresponding state, the torsionally flexible coupling is not damaged.

Preferably, the crankshaft rotation is released when the potential energy is zero and the kinetic energy of the torsional vibration system is maximum. In time, this may be the case a quarter of a period after passing through a minimum angle of rotation.

For example, the rotation of the crankshaft may be released even if or after a potential energy stored in the torsionally flexible coupling of the rotary vibrator reaches a maximum allowable energy or the potential energy stored in the torsionally flexible coupling of the rotary vibrator reaches a power necessary to start the internal combustion engine. A maximum allowable energy is z in this case. B. achieved when a twist angle reaches a magnitude maximum twist angle. The angle of rotation describes the rotation of the rotor relative to the crankshaft. An energy required for starting the internal combustion engine can be achieved, for example, if a predetermined angle of rotation is achieved which is smaller in magnitude than the maximum permissible angle of rotation. As a result, a power required for the starting process can be reduced in an advantageous manner. In particular, in cold internal combustion engines, higher starting power is required than with warm internal combustion engines.

The proposed method thus describes a swinging or swinging of the existing of the elastic coupling element and the rotating mass of the rotor mechanical system against a braked crankshaft. If the crankshaft is released again, the energy stored in the oscillated system can be used to drive the crankshaft.

It is also possible that a change in sign of the starting torque takes place in such a time that a resonant frequency of the rotary oscillator is excited. Here, the sign change z. B. temporally corresponding to the resonant frequency.

It is possible that the blockage of the crankshaft already at a previous shutdown or exhibition of the internal combustion engine, for. B. when parking the vehicle takes place. Thus, in a subsequent turn on or when activating the ignition described the starting process immediately.

The proposed method advantageously makes it possible to use an electric motor with a very low maximum starting torque which can be generated as the starting motor, since no friction losses of the crankshaft during starting by the starter motor have to be compensated for by preventing rotation of the crankshaft.

In a further embodiment, the rotation of the crankshaft is released after a minimum allowable twist angle or a predetermined twist angle has been reached and / or a change in sign of the starting torque has occurred during the application of a negative starting torque. The modulation of the starting torque can thus take place until a minimum permissible angle of rotation is reached, and preferably not exceeded, and a sign change of the negative starting torque to a positive starting torque takes place. In this case, the potential energy stored in the rotary vibrator is applied to the Crankshaft transmitted, that a rotation of the crankshaft takes place in the preferred direction of rotation. Thus, the internal combustion engine can be started in an advantageous manner in the preferred direction of rotation.

Preferably, the release of the rotation of the crankshaft occurs after a minimum allowable twist angle or a predetermined minimum twist angle has been reached during a negative starting torque application, a sign change of the starting torque and during the subsequent application of a positive starting torque an amount of a difference between a current twist angle and a zero angle falls below a predetermined threshold. Thus, the release occurs in the vicinity of the zero crossing of the rotation angle.

Further preferably, after release of the rotation of the crankshaft, only a positive starting torque can be generated by the starter motor and transmitted to the crankshaft via the elastic coupling element.

As a result, a torque acting on the released crankshaft is maximized in an advantageous manner, as a result of which the above-explained static friction of the internal combustion engine as well as compression and sliding friction torques of elements of the internal combustion engine can be overcome.

In a further embodiment, after the rotation of the crankshaft has been released, ignition of a fuel-air mixture takes place in a combustion chamber of at least one cylinder of the internal combustion engine. Preferably, an ignition takes place when a piston of the internal combustion engine reaches a top dead center in or after a compression stroke during a rotation of the crankshaft in the preferred direction of rotation.

The ignition can be a spark ignition or auto-ignition. In spark ignition, for example, an ignition timing of at least one of the at least one cylinder associated spark plug can be adjusted accordingly. In a spark ignition, for example, a temperature and / or pressure in the combustion chamber can be adjusted accordingly.

By the ignition, which takes place in particular at the time of reaching the top dead center in or after a compression stroke, another, acting in the preferred direction, torque is generated on the crankshaft, which supports the starting process. In this way, a maximum producible torque of the starter motor can be further reduced.

In another embodiment, before the blockage of the rotation of the crankshaft, a starting torque curve of the starting torque is generated such that a rotation of the crankshaft takes place. Here, the rotation of the crankshaft is mechanically released. In particular, a starting torque curve can be generated such that a static friction torque of the crankshaft and of elements, for. B. piston, the internal combustion engine is overcome and a breakaway of the crankshaft takes place. For example, the starting torque in the starting torque curve may be generated such that the crankshaft is positioned at a predetermined crankshaft position. The predetermined position may for example be a blocking position, wherein the crankshaft is mechanically blocked only in the blocking position. The starting torque curve can be generated such that it has at least one change of sign (modulation of the starting torque).

Alternatively or cumulatively, the starting torque curve, z. B. with at least one change of sign of the starting torque, carried out such that the crankshaft is pre-positioned in a predetermined crankshaft position. In this way, advantageously, a starting cylinder and / or a volume of the combustion chamber of the starting cylinder can be adjusted before the starting operation. A starting cylinder here describes a cylinder of the internal combustion engine, which reaches its upper compression dead center in a (shared) rotation of the crankshaft in the preferred direction of rotation as the first of several cylinders, wherein the upper compression dead center describes the top dead center in or after a compression stroke.

Also, the starting torque curve can be generated such that a predetermined fuel pressure is built up. For this purpose, the crankshaft mechanically directly or indirectly, for. B. via a camshaft, drive a pump of a fuel injection system. This is the case in particular in so-called common rail Otto or common rail diesel engines. Thus, advantageously by rotation of the crankshaft before the start of the actual starting process, a desired fuel pressure can be built up, which is necessary for subsequent injection and ignition, in particular in diesel internal combustion engines.

This is so even before a mechanical blockage of the rotation of the crankshaft, z. B. generated by a modulation of the starting torque a rotational movement of the crankshaft. However, this rotation does not serve to start the internal combustion engine, but a pressure build-up and / or a pre-positioning of the crankshaft.

In a preferred embodiment, the crankshaft is positioned at a predetermined blocking position prior to the starting time. Here, the blocking position may designate a position of the crankshaft in which rotation of the crankshaft may be blocked.

In particular, the blocking position can be predetermined by a mechanical design of the blocking agent. Preferably, therefore, the blocking means is designed such that it can mechanically block the rotation of the crankshaft in more than one crankshaft position.

The blocking position can also be adjusted depending on a desired start cylinder. Here, the crankshaft can be positioned such that, starting from the current position of the crankshaft, a desired cylinder during a rotation of the crankshaft in the preferred direction of rotation as the first of several cylinders reaches the top compression dead center.

Also, the blocking position can be adjusted depending on a desired volume of a combustion chamber of the (start) cylinder. So z. B. a small volume of the (start) cylinder at the beginning of the starting process overcoming the following upper compression dead center, however, an ignition of the fuel-air mixture is possibly difficult, whereby a labor contribution to overcome the second upper compression dead center is difficult , On the other hand, a large volume of the combustion space at the start of the cranking operation requires a higher energy to overcome the first following upper compression dead center, but facilitates the first combustion and thus the further startup operation due to the higher work contribution due to the ignition.

Positioning of the crankshaft in a predetermined blocking position can also be at a previous shutdown or shutdown of the internal combustion engine, for. B. by a suitable deceleration of the rotation of the crankshaft. As a result, rotational energy of the crankshaft which is still present when the engine is switched off can advantageously be used to set the desired blocking position.

In another embodiment, a regenerative operation mode of the starter motor is activated when a termination condition of the cranking operation is satisfied after the rotation of the crankshaft is blocked. In the generator operating mode, kinetic energy generated by the rotary oscillator is converted into electrical energy by the starter motor, which can also be operated as a generator. As a result, the rotational oscillator energy can be withdrawn in an advantageous manner.

If a termination condition of the starting operation is fulfilled, then the blockage of the rotation of the crankshaft can be released immediately or upon reaching a predetermined counter-torque, wherein the counter-torque designates the torque exerted by the crankshaft on the elastic coupling torque. As a result, an amplitude of the torsional vibration can be reduced as quickly as possible in an advantageous manner. Alternatively, the mechanical blockade can be solved upon reaching a lower threshold value of a fuel pressure, wherein the lower threshold value defines a fuel pressure, which no longer allows a start of the internal combustion engine safely. Further alternatively, the release of the blockade only at the beginning of a renewed starting operation, but before the proposed start time, take place, for example, when the internal combustion engine is reactivated after a previous shutdown of the internal combustion engine.

A regenerative operation mode of the starter motor may also be activated when the condition (s) for releasing the blockage of the crankshaft is / are satisfied, but the release does not occur due to a malfunction. As a result, the rotary oscillator can be actively deprived of energy, whereby operational reliability is increased.

An abort condition of the starting process can be met, for example, if a defect of the blocking agent and / or its activation is detected.

This results in an advantageous manner that an operational safety during the starting process is ensured even if energy is already stored in the rotary oscillator, but the starting process must be terminated. This energy can be converted into electrical energy by a so-called recuperation in an advantageous manner, whereby z. B. a battery of the vehicle can be charged.

In a further embodiment, a target torque of the starter motor increases continuously with decreasing difference between a current twist angle and the minimum allowable or the predetermined negative twist angle. Here, a sign-sensitive consideration of both the setpoint torque and the difference takes place. This can be done in particular in a half-oscillation from a positive reversal angle to a negative reversal angle, wherein a reversal angle denotes a rotation angle at which a reversal of the direction of rotation of the rotor takes place. Approaching the current twist angle the minimum allowable Angle of rotation, so decreases the previously described difference. At the same time, however, the nominal torque of the starter motor increases. Thus, the rotation of the rotor against the preferential direction of rotation, which is caused by a negative target torque, less supported with decreasing difference or, if the target torque is positive, this even counteracted.

As a result, a mechanical damage of the elastic coupling element can be avoided in an advantageous manner, as falling below the minimum allowable or the predetermined negative rotation angle is avoided. Alternatively, the target torque of the starter motor may gradually increase in one or more steps as the difference between the actual twist angle and the minimum allowable or the predetermined negative twist angle decreases. So z. B. conceivable that falls below a predetermined difference, the target torque is suddenly set to a desired value of zero and when reversing the direction of rotation of the rotor or upon reaching the minimum allowable or predetermined negative rotation angle abruptly a positive target torque is set. Another alternative is conceivable that when falling below a predetermined difference, the target torque is suddenly set to a positive or negative target torque.

Alternatively or cumulatively, the target torque of the starter motor decreases gradually with decreasing difference between the maximum allowable twist angle or a predetermined positive twist angle and a current twist angle, or in one or more steps. This can be done in particular in a half-oscillation from a negative angle of return to a positive angle of reversal.

The predetermined negative angle of rotation or the predetermined angle of rotation in this case denote angle of rotation, when it reaches enough energy is stored in the rotary oscillator to start the internal combustion engine.

This results in an advantageous manner an increased reliability in the excitation of the previously described rotary vibrator for starting the internal combustion engine, since permissible angle of rotation is not exceeded or exceeded.

In a further embodiment, a defect of the torsional vibration system is detected if a frequency of the sign change of the starting torque deviates from a predetermined resonance frequency by more than a predetermined amount. If the sign of the starting torque is always changed, even if the direction of rotation of the rotor of the starter motor is reversed, then times of the change of sign can be detected and from this a frequency of the change of sign can be determined. If this frequency deviates from a known resonant frequency of the torsional vibration system determined, for example, by tests or modeling, then a defect of the rotary vibrator can be detected.

Alternatively or cumulatively, a defect of the torsional vibration system may be detected when a difference between amounts of the reversing angle immediately following the starting operation, for example, the maximum positive and maximum negative rotational angles, exceeds a predetermined difference. During cranking, an amount of twist angle may increase continuously. However, this increase is limited by dynamic properties of the rotary oscillator in height. If the difference between the amounts of successive reversal angles exceeds a predetermined level, the angle of rotation actually achieved during the starting process thus increases or decreases disproportionately. Also in this case, a defect of the torsional vibration system can be detected.

Alternatively or cumulatively, a defect of the torsional vibration system can be detected if a temporal twist angle course deviates from an expected course by more than a predetermined amount. The expected course here refers to a time course of the angle of rotation, which will adjust due to the dynamic properties of the rotary vibrator. In a torsionally flexible coupling with linear properties, such as a linear torsion spring, z. B. set as expected course a sinusoidal course.

Alternatively or cumulatively, a defect of the torsional vibration system can be detected when an amount ratio between reversing angles immediately following each other during the starting operation exceeds or falls below a predetermined amount.

Further alternatively or cumulatively, a defect of the torsional vibration system can be detected if a ratio of the mechanical power generated by the starter motor exceeds the predetermined angle of rotation reaches a predetermined level. For this purpose, a current twist angle and the mechanical power generated by the starter motor can be detected or determined. The mechanical power generated by the starter motor can be determined, for example, as a function of an electric power required by the starter motor.

If a defect of the torsional vibration system is detected, then a termination condition of the starting operation can be fulfilled.

This results in an advantageous manner an increase in reliability during a starting operation, since the functionality of the rotary vibrator can be monitored.

Further proposed is a device for starting an internal combustion engine of a motor vehicle. The device comprises at least one internal combustion engine, at least one crankshaft, at least one starter motor, at least one torsionally flexible coupling element and at least one control device. A rotor of the starter motor is mechanically connected via the torsionally flexible coupling element with the crankshaft. By means of the internal combustion engine, a drive torque in a preferred direction of the internal combustion engine can be exerted on the crankshaft. By the starter motor in a starting process, a starting torque can be generated and transmitted via the elastic coupling element to the crankshaft. By means of the control device, the starting torque is adjustable.

According to the invention the device comprises at least one locking means for the crankshaft, wherein by means of the blocking means a rotation of the crankshaft is mechanically blocked and released. In particular, the blocking means, as explained above, be designed as a crankshaft brake or as a crankshaft lock.

The proposed device allows this advantageously the execution of the previously described method.

In a preferred embodiment, the crankshaft and / or the blocking means is / are configured and / or arranged such that a blockage of the rotation of the crankshaft in several crankshaft positions can be carried out. As a result, a desired starting cylinder and optionally a desired volume of a combustion chamber of the starting cylinder can be set at the beginning of the starting operation in an advantageous manner.

The invention will be explained in more detail with reference to an embodiment. The figures show:

1 a schematic block diagram of a drive train,

2 a schematic diagram of a blocking agent in a first embodiment,

3 a schematic diagram of a blocking agent in a second embodiment,

4 a schematic diagram of a blocking agent in a third embodiment and

5 a schematic time course of a starting torque, a rotational speed of an internal combustion engine, a speed of the starter motor and an angle of a torsionally flexible coupling element.

Hereinafter, like reference numerals designate elements having the same or similar technical features.

In 1 is a schematic block diagram of a device according to the invention 1 for starting an internal combustion engine 2 shown. The device 1 includes in addition to the internal combustion engine 2 a crankshaft 3 the internal combustion engine 2 , a starter motor 4 and a torsionally elastic coupling element 5 through which the crankshaft 3 with a rotor 6 the starter motor 4 mechanically connected. The torsionally elastic coupling element 5 in this case forms the torsionally flexible coupling according to the invention and may for example be a torsion spring. Furthermore, the device comprises 1 a blocking agent 7 through which a rotation of the crankshaft 3 mechanically blocked or released. Also shown is a transmission 8th , a drive shaft 9 and one through the drive shaft 9 drivable rotatable wheel 10 of a motor vehicle.

Not shown is a control device which the starter motor 4 so controls that during a starting process that of the starter motor 4 generated starting torque AM (see 5 ) has at least one, but preferably several, sign changes. At a starting time of the starting process or before the start time, the blocking agent 7 be activated, causing a rotation of the crankshaft 3 is mechanically blocked. Mechanically blocked here means that a rotation of the crankshaft 3 not possible. At the start time is by the starter motor 4 z. B. generates a negative starting moment AM. This will cause the rotor 6 the starter motor 4 contrary to a preferential direction of rotation, indicated by an arrow 11 is shown twisted. Because a rotation of the crankshaft 3 is blocked, the rotor tenses 6 the torsionally elastic coupling element 5 , Thus, the starting torque AM counteracts that of the torsionally elastic coupling element 5 generated restoring moment. This increases with a decreasing, ie increasing in magnitude, angle of rotation W (see 5 ). The restoring torque exceeds that of the starter motor 4 generated torque from the amount, so there is a spin reversal. At this time or after this time, a reversal of the direction of rotation can also take place. At the time of reversing the direction of rotation Then there is a change of sign of the starting torque AM, the starter motor 4 generated from this point on a positive starting moment AM and the rotor 6 in preferred direction 11 drives. A further change of sign to a negative starting torque AM occurs when a renewed reversal of the direction of rotation of the rotor 6 from a direction of rotation in the preferred direction of rotation in a direction opposite to the preferred direction of rotation. Thus, a swinging occurs through the blocked crankshaft 3 , the torsionally flexible coupling element 5 and the rotor 6 formed rotary vibrator. During the excitation energy is stored in the rotary oscillator, wherein at the time of reversal of the rotor 6 the stored energy in the rotary oscillator is completely stored as potential energy.

If a minimum allowable angle of rotation W, ie a maximum allowable angle of rotation W, during a rotation of the rotor 6 achieved contrary to the preferred direction of rotation, it takes place, as previously described, a change of sign of the starting torque AM. In the following on this change of sign as next in time next zero crossing of the angle of rotation W is the blocking agent 7 disabled, causing the rotation of the crankshaft 3 is released. Thus, the energy stored in the torsional vibrator at this time as kinetic and potential energy at least partially becomes a rotation of the crankshaft 3 in preferred direction 11 cause. That at this time on the crankshaft 3 transmitted torque can advantageously greater than a breakaway torque and in the internal combustion engine 2 be existing compression and sliding friction moments. Thus, the crankshaft 3 be driven so that the internal combustion engine 2 can be started.

Even before the crankshaft is locked 3 can the released crankshaft 3 be positioned by generating an appropriate course of the starting torque AM in a predetermined blocking position. For this purpose, for example, a modulation of the starting torque AM take place, that is to say a chronological progression of the starting torque AM is generated with at least one change of sign.

The described method for starting the internal combustion engine 2 can be combined with other starting methods. Thus, it is possible to carry out a known towing start-up method in an operating internal combustion engine, wherein the starter motor 4 without activation of the blocking agent 7 and without change of sign a starting moment AM in preferred direction of rotation 11 , So a positive starting torque AM, and thus generates the internal combustion engine 2 anlässt.

Also, the proposed method may be combined with a method in which energy of a rolling vehicle for starting or starting the internal combustion engine 2 is used by a torque transmitting connection between a wheel 10 of the vehicle and the internal combustion engine 2 is activated. A control device can, for example, in dependence on input variables such as a temperature of the internal combustion engine 2 , a state of the blocking agent 7 , a vehicle speed, a pedal position and / or a selector lever position determine which method is carried out for starting. The control device can also monitor the selected method and, if appropriate, stop it and subsequently carry out a different method.

It is also possible that before blocking the crankshaft 3 through the blocking agent 7 a modulation of the starter motor 4 generated starting torque AM is such that a desired fuel pressure is built up.

In order to store a maximum possible energy in the rotary oscillator, the starting torque AM is controlled such that in a last half period with a negative starting torque AM just a minimum allowable angle of rotation W is achieved, but to damage the elastic coupling element 5 to avoid, is not exceeded. Will the minimum allowable angle of rotation W of the elastic coupling element 5 reaches a sign change of the starting torque AM, which is now positive. If no deactivation of the blocking agent occurs due to a malfunction 7 So, the crankshaft remains 3 locked, the starting torque AM can be changed immediately after detection of the malfunction to a minimum value and a generator operating mode of the starter motor 4 to be activated. Thus, the starter motor 4 operated until reaching a maximum angle of rotation W as a generator, whereby the rotary oscillator is actively deprived of energy. In this case, for example, a predetermined number of further deactivation attempts of the blocking agent can take place or the starting process can be aborted.

Will, z. B. in the case of a defect of the rotary oscillator, the starter motor 4 or the blocking agent 7 , a minimum allowable or a predetermined negative twist angle W is not reached after a predetermined period of time, a termination condition of the cranking operation may be satisfied. An abort condition can also be met, for example, if an amount ratio of successive reversal angles is one or more times below a predetermined minimum value.

Is the blocking agent 7 designed such that the crankshaft 3 can be blocked only in predetermined crankshaft positions, so the number of cylinders can be limited, which can be used as a starting cylinder. In this case, a start cylinder is understood to be the one cylinder whose top dead center in the case of a rotation of the crankshaft 3 in preferred direction 11 is overcome first from this predetermined crankshaft position out. This can usually, but not necessarily, be the cylinder that is also ignited first. For a four-stroke engine with an even number of cylinders, the number of starting cylinders may be two, for a three-cylinder engine the number is usually one. Is, z. B. due to an embodiment of the blocking agent 7 , not every cylinder can be used as a start cylinder, so can already when switching off the internal combustion engine 2 by a corresponding crankshaft position control the crankshaft 3 be positioned so that a desired start cylinder is set.

Advantageously, the blocking agent 7 designed or configured so that in more than one crankshaft position, the rotation of the crankshaft 3 can block. For example, the blocking agent 7 be formed such that it is the crankshaft 3 can block in 36 equidistant crankshaft positions, so every 10 ° crankshaft angle. In this case, the blocking agent can 7 z. B. by a not shown on a housing of the internal combustion engine 2 fastened radially displaceable bolt may be formed, which can be inserted into bores or recesses in the crankshaft 3 are introduced.

It is also possible that the blocking agent 7 not directly a rotation of the crankshaft 3 blocked, so directly with the crankshaft 3 interacts, but on one with the crankshaft 3 coupled further shaft of the internal combustion engine 2 , z. B. on a camshaft acts.

For a reliable cold start of diesel engines is usually a preheating of sucked air and z. B. of parts of a combustion chamber by appropriate heating or annealing, z. B. glow plugs performed. The proposed method for starting the internal combustion engine 2 in this case advantageously allows a content of a combustion chamber of a cylinder, in contrast to conventional starting methods, to be replaced before the first compression. This results in an advantageous manner that the heating or annealing means have a longer period over which they can act on the contents of the combustion chamber. Of course, it is conceivable that a cylinder-dependent control of the heating or annealing occurs, so z. B. a preheating of the starting cylinder or introduced into the combustion chamber of the starting cylinder air is intense or begins earlier. In a motor with spark ignition, z. As in a gasoline engine, an ignition energy can be increased in an ignition of the starting cylinder to achieve a reliable ignition. Furthermore, compared to conventional starting methods, very early fuel pre-injections can take place in the starting cylinder, since, as explained above, the contents of the combustion chamber are no longer exchanged during the starting process and thus a longer time is available for vaporization of the fuel.

The proposed method for starting the internal combustion engine 2 allows advantageously that a maximum to be generated starting torque AM of the starter motor 4 can be dimensioned as small as possible. Under these conditions, it may be advantageous for the internal combustion engine 2 During the starting process as early as possible makes its own contribution to torque, possibly already with overcoming the first upper compression dead center.

To determine an injection or ignition timing is usually required that a crankshaft or camshaft angle is known. For example, (absolute) angle sensors can be used to detect such an angle. These can be improved at low resolution by existing incremental sensors. Maintaining conventional incremental sensors on the crankshaft 3 and / or camshaft, a number and location of signal edges may be optimized for early detection of injection angles or ignition angles. Such a detection can also in a contrary to the preferred direction of rotation 11 rotating starter motor 4 respectively. When parking the internal combustion engine 2 At this time, information available, eg. Example, a present crankshaft angle, are used as initial values for a new startup, possibly even after a non-volatile storage when the control units were switched off in the meantime. It is also possible that locally in a control unit existing information with a bus system, z. B. a CAN bus, transmitted information from other control units are adjusted and used only as initial values, if there is no deviation.

Will the blocking agent 7 already at the shutdown of the internal combustion engine 2 actuates and remains the blocking agent 7 until the next start of the internal combustion engine 2 activated at the time of activation of the blocking agent 7 set crankshaft angles are used as initial value at the next start.

A rotor angle of the rotor 6 can, together with a certain crankshaft angle, for determining the angle of rotation W between the crankshaft 3 and the rotor 6 and thus for determining the rotation of the elastic coupling element 5 be used. In this case, the angle of rotation W can be made plausible by predetermined and / or determined torques and / or detected rotational accelerations using mathematical models.

It is also possible that means for valve train, for example, camshaft phaser, a cylinder deactivation in addition to or alternatively to set a predetermined crankshaft position with activated blocking agent 7 control such that a predetermined filling of a combustion chamber is adjusted.

Further, a defect of the blocking agent 7 and / or its activation are detected. This z. B. be detected, whether in an activated state of the blocking agent 7 Movements of the crankshaft 3 respectively. These movements can z. B. be detected by the aforementioned crankshaft or camshaft sensor. This may be an impermissible movement of the crankshaft 3 detected when an amplitude of the movement is above a predetermined value, wherein the predetermined value is an elasticity of the crankshaft 3 and the blocking agent 7 considered.

Alternatively, the blocking agent 7 a means for detecting a Einrückweges, z. B. of pins or a locking bar 18 (see eg 2 ), wherein in an engaged state, the rotation of the crankshaft 3 is blocked. If an output signal of the means for detecting the engagement path does not change in a predetermined manner upon activation, a defect can be detected.

In the case of an electric magnet acting as an actuator for the blocking agent 7 is used, a current waveform in windings of the electric magnet or a change in an inductance of the electric magnet, for. B. in response to a current gradient at a given voltage jump, are detected, wherein a defect is detected when these sizes differ from predetermined sizes.

In the case of an electric motor as an actuator for the blocking agent 7 can be detected, whether a rotation of the rotor of the electric motor of a desired rotation upon activation of the blocking means 7 corresponds to whether a voltage is induced in the electric motor or a current consumption of the electric motor deviates from a predetermined current consumption. It is also possible to detect whether there is no commutation in the case of a BLDC motor.

Also may be a defect of the blocking agent 7 be detected if after deactivation of the blocking agent 7 no or little movement of the crankshaft for a predetermined period of time 3 he follows.

2 shows a schematic diagram of a blocking agent 7 in a first embodiment. The blocking agent 7 includes a gear 12 which is about a central axis of rotation 13 rotatably mounted. The gear 12 can be on the crankshaft 3 (please refer 1 ) be fixed torsionally rigid. This is where the gearwheel points 12 teeth 14 on top of each, a rounded section 15 and a straight section 16 exhibit. Here are the teeth 14 in a cross section with a sectional plane perpendicular to the central axis of rotation 13 a quarter-circle-shaped cross section. The straight sections 16 in this case run in the radial direction relative to a center 17 of the gear 12 ,

Furthermore, the blocking agent comprises 7 a stop bar 18 which is rotatable about an axis of rotation 19 of the stop bar 18 is stored. The locking bar 18 has a latching nose on a gear-side end 20 on, with the latch 20 with the teeth 14 can interact. The rounded sections 15 the teeth 14 are here designed such that when the gear 12 counterclockwise, based on the central axis of rotation 13 defined, turns, a bit 21 of the ratchet tooth 20 along the rounded tooth surface of the teeth 14 can slide without latching with your teeth. In this case, a rotational movement of the gear 12 and thus also the crankshaft 3 Approved. The straight sections 16 the teeth 14 are here designed such that when the gear 12 turns clockwise, one of the latch 20 trained stop surface 22 at the straight section 16 strikes, causing the gear 12 with the locking bar 18 locked. In this case, a rotational movement of the gear 12 and thus also the crankshaft 3 blocked.

The blocking agent 7 further includes a first spring 23 and another spring 24 , Here is the other spring 24 at a detention-side section of the locking beam 18 attached, with the first spring relative to the axis of rotation 19 of the stop bar 18 on a section of the locking bar opposite the latching-side-side section 18 is attached. Furthermore, the blocking agent comprises 7 an actor 25 who is the other spring 24 in or against a vertical direction indicated by an arrow 26 is shown, can move. In a release position, the other spring 24 through the actor 25 in a vertical direction 26 positioned in the upper position. In this release position exercises, especially exclusively, the first spring 23 a force on the stop bar 18 on, so that the latch 20 due to the rotation of the locking bar about the axis of rotation 19 contrary to in 3 illustrated vertical direction 26 moved upwards and thus the rotational movement of the gear 12 releases in both directions of rotation.

In a blocking position, the other spring 24 through the actor 25 in a vertical direction 26 positioned lower position. This exercises both the first spring 23 as well as the other spring 24 a force in the vertical direction 26 on the stop bar 18 on. As both forces, with respect to the axis of rotation 19 , on opposite sections of the locking beam 18 act, no rotation of the locking bar 18 and thus no release of the rotational movement in both directions of rotation. Rather, in this blocking position, the rotational movement of the gear 12 locked clockwise. Counterclockwise, the rotational movement, as previously described, against the spring force of the other spring 24 possible.

3 shows a schematic diagram of a blocking agent 7 in a second embodiment. The blocking agent 7 includes a gear 12 which is about a central axis of rotation 13 rotatably mounted. The gear 12 can be on the crankshaft 3 (please refer 1 ) be fixed torsionally rigid. This is where the gearwheel points 12 teeth 14 on, with the teeth 14 in a cross section with a sectional plane perpendicular to the central axis of rotation 13 have a trapezoidal cross-section.

Furthermore, the blocking agent comprises 7 a stop bar 18 which is rotatable about an axis of rotation 19 of the stop bar 18 is stored. The locking bar 18 has a latching nose on a gear-side end 20 also with a trapezoidal cross-section, wherein the locking lug 20 with the teeth 14 can interact. The blocking agent 7 further includes a first spring 23 and another spring 24 , Here is the other spring 24 at a detention-side section of the locking beam 18 attached, with the first spring 23 relative to the axis of rotation 19 of the stop bar 18 on a section of the locking bar opposite the latching-side-side section 18 is attached. Furthermore, the blocking agent comprises 7 an actor 25 who is the other spring 24 in a vertical direction, by an arrow 26 is shown, can move. In a release position, the other spring 24 through the actor 25 in a vertical direction 26 positioned in the upper position. In this release position exercises, especially exclusively, the first spring 23 a force on the stop bar 18 on, so that the latch 20 due to the rotation of the locking bar 18 around the axis of rotation 19 contrary to in 3 illustrated vertical direction 26 moved upwards and thus the rotational movement of the gear 12 releases in both directions of rotation.

In a blocking position, the other spring 24 through the actor 25 in a vertical direction 26 positioned lower position. In this blocking position exercises both the first spring 23 as well as the other spring 24 a force in the vertical direction on the locking bar 18 on. Because both forces are on, with respect to the axis of rotation 19 , opposite sections of the locking beam 18 act, no rotation of the locking bar 18 and thus no release of both rotational movement. Rather, in this blocking position, the rotational movement of the gear 12 locked in both directions.

4 shows a schematic diagram of a blocking agent 7 in a third embodiment. The blocking agent 7 includes two brake pads 27 on opposite sides of the crankshaft 3 (please refer 1 ) are arranged. Furthermore, the blocking agent comprises 7 an actor 25 in and against a longitudinal direction, indicated by an arrow 28 symbolized, can be moved. Furthermore, the blocking agent comprises 7 the respective brake pads 27 assigned lever arms 29 , each rotatable about axes of rotation 30 are stored. Here, the axes of rotation run 30 perpendicular to the longitudinal direction 28 , In 4 is shown that the lever arms 29 have two arm portions. A first arm section 31 extends here from the axis of rotation 30 to the corresponding brake pad 27 , A second arm section 32 extends from the brake pad 27 away and includes with the first arm portion an angle α. At a free end of the second arm portion 32 is the lever arm 29 mechanically with the actuator 25 , z. B. via a pull rope connected. Furthermore, the blocking agent comprises 7 a feather 33 between the brake pads 27 is arranged. In a starting position of the spring 33 , in which the spring is not biased, are the brake pads 27 not in mechanical contact with the crankshaft 3 , Will now the actor 25 longitudinal 28 procedure, so are the brake pads 27 due to the mechanical connection of the actuator 25 with the lever arms 29 and due to the training and storage of the lever arms 29 against the spring 33 generated spring force to the crankshaft 3 pressed, creating a mechanical contact between the brake pads 27 and the crankshaft 3 is made and the crankshaft 3 is slowed down. In this blocking state is a rotational movement of the crankshaft 3 not possible. Will the actor 25 against the longitudinal direction 28 procedure, so the brake pads are by the spring 33 generated spring force from the crankshaft 3 moved away. This achieves a release state in which a rotational movement of the crankshaft 3 is released.

5 shows a schematic course of a starting torque AM by a solid line, a speed DV of an internal combustion engine 2 (please refer 1 ) by a dashed line, a speed DA of the starter motor 4 by a dash-dot line and a twist angle W of a torsionally flexible coupling element 5 by a dotted line over a time t.

In a first phase P1 is a modulation of the starting torque AM such that the crankshaft 3 breaks loose. This takes place at the end time E_P1 of the first phase P1. In a second phase P2 is a modulation of the starting torque AM such that the crankshaft 3 is moved in a predetermined angular range such that one with the crankshaft 3 coupled fuel pump can build a desired injection pressure. From the end time E_P2 of the second phase P2, the starting torque AM is controlled such that the crankshaft 3 is positioned in a crankshaft position, in which a blockage of the crankshaft 3 is possible. At a blocking time B, the rotational movement of the crankshaft 3 blocked. In a fourth phase P4 energy is now accumulated in the above-explained rotary oscillator, with maximum and minimum amplitudes of the speed DA and the angle W increase. After an end time E_P4 of the fourth phase P4 takes place in a fifth phase P5, a release of the blockade, resulting in a release time L, the speed DV of the internal combustion engine 2 fast in time, z. B. suddenly, increased.

It can also be a control of the blocking agent 7 temporally before the blocking time 3 and / or before the release time L done.

So can side surfaces of the teeth 14 and the latch 20 (please refer 2 and 3 ) be frictionally connected when acting on these surfaces a force, for. B. during a blockage of the crankshaft 3 , This force is essentially a twist angle W of the elastic coupling element 5 dependent. In particular, the frictional force generated by the frictional connection can prevent release, for example when the frictional force is greater than that of the springs 23 . 24 on the stop bar 18 is exercised lifting power. However, the frictional force will be low when the elastic coupling element 5 is relaxed, so has a magnitude small twist angle W.

Thus, the time interval in which the blocking agent is 7 the rotation of the crankshaft 3 should be released, small. During the fourth phase P1, a period duration, that is to say a time duration between two consecutive identical sign changes of the direction of rotation, can be for example approximately 120 ms. Thus, even temporally successive magnitude maxima of the angle of rotation W are only about 60 ms apart. As a result, a time interval for release can include periods of time from 0 ms to 20 ms.

In general, the cost and the space requirements of a setting device, z. B. of in 2 and 3 represented actuator 25 , the blocking agent 7 with increasing maximum power, which is determined by the product of force and displacement per operating time. Thus, if a positioning time, which in this case corresponds to the duration of the release of the rotation, increased, so costs and space can be reduced.

In an advantageous design of the blocking agent 7 So instead of a direct mechanical coupling of the actuator 25 with the locking bar 18 a mechanical coupling via the other spring 24 realized. This further spring 24 practically serves as a buffer for one of the actuator 25 generated job energy.

Is the actor 25 z. B. as an electric motor, optionally with a transmission, designed, this actuator can 25 be addressed before the release time L, wherein at the latest to the release time L, a movement of the locking bar 18 should be done. This control can until the end of the movement of the locking bar 18 or even beyond.

Is the adjusting device of the blocking agent 7 , ie z. B. the actuator 25 , via a spring, for example, the other spring 24 , with a release element, eg. B. the locking bar 18 , coupled, so can the actor 25 at a drive time which is a predetermined period of time, e.g. B. 70 ms, before the desired release time L is controlled such that a aktorseitiges end of the other spring 24 in a release direction, in this case against the vertical direction 26 is oriented, is moved. From this point on is z. B. a motor of the actuator 25 accelerated. The during this movement in the release direction building up spring force, the release element, so the locking bar 18 , also accelerated in the release direction, this does not exceed the above-explained frictional force by the angle of rotation W of the elastic coupling element until a further time, which is temporally after the activation time and before the release time L 5 dependent frictional connection between the teeth 14 and the ratchet tooth 20 is produced. In this case, the activation time and that of the actuator 25 generated driving force such as a function of a time course of the angle of rotation W of the elastic coupling element 5 chosen that the spring force exceeds the friction force and thus the locking bar to the previously explained further time 18 accelerated in the release direction and thus moved. In such a method, the release time L is thus set virtually automatically.

Here only the locking bar must 18 and part of the other spring 24 be accelerated, wherein in the case of a direct mechanical coupling of the actuator 25 with the locking bar 18 also a possibly via a transmission with the other spring 24 connected rotor of the actuator 25 to accelerate and thus a comparatively larger moment of inertia would be overcome. This would increase the performance of the actuator 25 require.

At the in 3 illustrated trapezoidal cross sections of the teeth 14 and the latch 20 takes with increasingly traveled path of the stop bar 18 in the release direction, the distance between a tooth 14 and the latch 20 continuously to, so after the beginning of the movement of the locking bar 18 the likelihood of unwanted re-contact of the side surfaces, the friction-based braking of the locking bar 18 would cause sinks. The locking bar 18 is therefore accelerated unchecked. The spring force hardly decreases, because the actuator 25 the actuator end of the other spring 24 now moves faster accordingly.

Accordingly, a control of the blocking agent 7 take place before the blocking time B, wherein the frictional force when moving the latch 20 against the release direction, ie in the vertical direction 26 , is overcome.

The increasing angle of rotation W of the elastic coupling element 5 causes an increasing torque on the crankshaft 3 being accelerated. The locking bar 18 is now so far in the release direction 18 Moves that no mechanical contact between the teeth 14 and the latch 20 can occur more.

After this, the activation of the actuator 25 be switched off.

Previously, the method of premature activation of an actuator of the blocking agent 7 for the in 2 and 3 illustrated embodiments explained. Of course, the method explained is also for further embodiments of the blocking agent 7 executable, in particular for embodiments in which the adjusting device of the blocking agent 7 is connected via a resilient element with a release element. In this case, in time before a blocking time B and / or before a desired release time L, the adjusting device can be controlled in such a way that a device-side end of the elastic element is moved counter to or in a release direction. In this case, a drive time and / or the force generated by the actuating device in such a manner depending on a time profile of the angle of rotation W of the elastic coupling element 5 be selected that at a further time, the force of the elastic member on the release member exceeds a frictional force between the release member and a crankshaft side corresponding element of the blocking means.

LIST OF REFERENCE NUMBERS

1

contraption

2

Internal combustion engine

3

crankshaft

4

starter motor

5

elastic coupling element

6

rotor

7

blocking agent

8th

transmission

9

drive shaft

10

wheel

11

Preferred direction of rotation

12

gear

13

rotation axis

14

tooth

15

rounded section

16

straight section

17

Focus

18

Rest bar

19

axis of rotation

20

locking lug

21

top

22

stop surface

23

first spring

24

another spring

25

actuator

26

vertical direction

27

brake pads

28

longitudinal direction

29

lever arm

30

axis of rotation

31

first arm section

32

another arm section

33

feather

AT THE

starting torque

THERE

Speed of the starter motor

DV

Speed of the internal combustion engine

W

angle of twist

P1

first phase

P2

second phase

P3

third phase

P4

fourth phase

P5

fifth phase

E_P1

End time of the first phase

E_P2

End time of the second phase

B

Blocking time

E_P4

End time of the fourth phase

L

Release time

t

Time

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• DE 102009033544 A1 [0002, 0005]
• DE 102012201102 A1 [0006]

Claims (10)

Method for starting an internal combustion engine ( 2 ), where a crankshaft ( 3 ) torsionally elastic with a rotor ( 6 ) of a starter motor ( 4 ), wherein in a starting process the starter motor ( 4 ) generates a starting torque (AM), which via the torsionally flexible coupling to the crankshaft ( 3 ), wherein at a starting time of the starting operation, a negative or positive starting torque (AM) is generated, wherein during the starting operation, at least one change of sign of the starting torque (AM), characterized in that before or at the starting time, a rotation of the crankshaft ( 3 ) is mechanically blocked, whereby the rotation of the crankshaft ( 3 ) is released, if or after a stored in a torsional vibration energy a maximum allowable energy or to start the internal combustion engine ( 2 ) reaches the required energy, wherein the torsional vibration system at least from the torsionally flexible coupling and the rotor ( 6 ) of the starter motor ( 4 ) consists. Method according to claim 1, characterized in that the rotation of the crankshaft ( 3 ) is released after a minimum allowable twist angle (W) or a predetermined negative twist angle (W) has been reached during exercise of a negative starting torque (AM) and / or a change in sign of the starting torque (AM). Method according to one of claims 1 or 2, characterized in that after release of the rotation of the crankshaft ( 3 ) an ignition of a fuel-air mixture in a combustion chamber of at least one cylinder of the internal combustion engine ( 2 ) he follows. Method according to one of claims 1 to 3, characterized in that before the blockage of the rotation of the crankshaft ( 3 ) a starting torque curve of the starting torque (AM) is generated such that a rotation of the crankshaft ( 3 ) he follows. Method according to one of claims 1 to 4, characterized in that the crankshaft ( 3 ) is positioned in a predetermined blocking position before the start time. Method according to one of claims 1 to 5, characterized in that when a termination condition of the starting operation is satisfied after the rotation of the crankshaft ( 3 ), a generator operating mode of the starter motor ( 4 ) is activated. Method according to one of claims 1 to 6, characterized in that a desired torque of the starter motor ( 4 ) continuously increases with decreasing difference between a current twist angle (W) and the minimum allowable or the predetermined negative twist angle (W) or gradually increases in one or more steps and / or that the target torque of the starter motor ( 4 ) decreases continuously as the difference between the maximum allowable twist angle (W) or a predetermined positive twist angle (W) and a current twist angle (W) decreases, or gradually decreases in one or more steps. Method according to one of claims 1 to 7, characterized in that a defect of the torsional vibration system is detected if a frequency of the sign change of the starting torque (AM) by more than a predetermined amount deviates from a predetermined resonant frequency and / or a difference between amounts during of the starting operation of immediately successive positive and negative reversal angles exceeds a predetermined difference and / or a deviation of a time angle course of an expected course exceeds a predetermined level and / or an amount ratio between during the starting process immediately successive positive and negative reversal angles exceeds or exceeds a predetermined amount and / or a ratio of the mechanical power generated by the starter motor to the achieved twist angle (W) exceeds a predetermined level. Device for starting an internal combustion engine ( 2 ) of a motor vehicle, comprising at least one internal combustion engine ( 2 ), at least one crankshaft ( 3 ), at least one starter motor ( 4 ), at least one torsionally elastic coupling element ( 5 ) and at least one control device, wherein a rotor ( 6 ) of the starter motor ( 4 ) via the torsionally elastic coupling element ( 5 ) with the crankshaft ( 3 ) is mechanically connected, wherein by means of the internal combustion engine ( 2 ) a drive torque in a preferred direction of the internal combustion engine ( 2 ) on the crankshaft ( 3 ) is exercisable, whereby by the starter motor ( 4 ) in a starting process a starting torque (AM) can be generated and via the elastic coupling element ( 5 ) on the crankshaft ( 3 ), wherein the starting torque (AM) can be regulated by means of the control device, characterized in that the device ( 1 ) at least one blocking agent ( 7 ) for the crankshaft ( 3 ), wherein by means of the blocking agent ( 7 ) a rotation of the crankshaft ( 3 ) is mechanically blocked and releasable. Device according to claim 9, characterized in that the crankshaft ( 3 ) and / or the blocking agent ( 7 ) is configured and / or arranged such that a blockage of the rotation of the crankshaft ( 3 ) is feasible in several crankshaft positions.

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