DE102013224890A1 - Method for controlling an internal combustion engine of a drive train of a motor vehicle and motor vehicle - Google Patents

Abstract

A method for controlling an internal combustion engine (3) of a drive train (2) of a motor vehicle (1), wherein the drive train (2) comprises the internal combustion engine (3), a transmission (6) and a vibration damping member (4) which is disposed between the internal combustion engine ( 3) and the transmission (6), comprises the steps of: determining a rotational speed of the internal combustion engine (3); Analyzing the determined rotational speed of the internal combustion engine; Determining, based on the speed analysis, whether there is a predetermined load operating condition in which an undesired load is applied from the driveline (2) to the vibration damping member (4); and if the predetermined load operating state is present, controlling the internal combustion engine (3) such that the torque of the internal combustion engine (3) is changed ramp-shaped.

Description

The invention relates to a method for controlling an internal combustion engine of a drive train of a motor vehicle and a motor vehicle having a controller that is configured to carry out the method.

In motor vehicles it is known to provide in the driveline between an internal combustion engine and a transmission of the motor vehicle a vibration damping member, such as e.g. a flywheel or a torsional damper or the like to absorb torsional vibrations generated by the internal combustion engine. The flywheel is typically designed as a dual mass flywheel, also called ZMS.

Internal combustion engines that operate in particular on the four-stroke principle, generate vibrations due to ignition and inertial forces that can lead to the excitation of gear and drive shaft vibrations. Such vibrations may be damped by the above-mentioned vibration damping member such as the twin-mass flywheel or the torsion damper or the like.

The dual mass flywheel typically has a primary flywheel disposed toward the internal combustion engine and a secondary flywheel disposed toward the transmission. The primary and the secondary flywheel are connected to each other with spring-damper units and attenuate resulting vibrations in the drive train from.

Despite the provision of a dual-mass flywheel, resonances may occur at certain rotational speeds of the internal combustion engine which typically occur at speeds of the internal combustion engine which are below their idling speed. However, such resonances can lead to high loads acting on the dual mass flywheel and claim it accordingly.

In order to avoid such loads for a dual-mass flywheel in a drive train of a motor vehicle, it is for example from the German patent specification DE 10 2009 019 081 B4 It is known to detect changes in a rotational speed of an internal combustion engine which may indicate the occurrence of a resonance. This is done by determining a speed difference between a local maximum speed value and a minimum speed value of the internal combustion engine. If the speed difference exceeds a threshold value, the injection of a fuel into the internal combustion engine is stopped, as a result of which the internal combustion engine itself is also stopped.

A similar method for protecting a dual-mass flywheel in a powertrain of a motor vehicle is known from the European published patent application EP 2 071 163 A2 known. Here, a first speed of a crankshaft of an internal combustion engine is determined at a first crankshaft angle and a second speed at a second crankshaft angle, and a speed difference is determined therefrom. If the speed difference exceeds a first threshold value, then a throttle valve is closed, if it exceeds a second threshold value, then an injection quantity of a fuel is reduced and if it exceeds a third threshold value, the fuel injection is stopped, which leads to the stopping of the internal combustion engine.

Although these methods are suitable for taking appropriate countermeasures when resonances occur. However, resonances are not the only effects that can cause a high load on a vibration attenuator and in particular a dual mass flywheel.

The object of the present invention is to provide an improved method for the method for controlling an internal combustion engine of a drive train of a motor vehicle and a motor vehicle which at least partially overcome the abovementioned disadvantages.

This object is achieved by the method according to the invention claim 1 and the motor vehicle according to claim 10.

An inventive method for controlling an internal combustion engine of a drive train of a motor vehicle, wherein the drive train the Internal combustion engine, a transmission and a vibration damping member which is coupled between the internal combustion engine and the transmission comprises the steps:
Determining a speed of the internal combustion engine;
Analyzing the determined rotational speed of the internal combustion engine;
Determining, based on the speed analysis, whether there is a predetermined load operating condition in which an undesirable load is applied from the driveline to the vibration damping member; and
if the predetermined load operating state is present, controlling the internal combustion engine such that the torque of the internal combustion engine is changed ramp-shaped.

A motor vehicle according to the invention comprises a power train having an internal combustion engine, a transmission and a vibration damping member coupled between the internal combustion engine and the transmission, and a controller, the controller configured to execute the above-mentioned method.

Further advantageous embodiments of the invention will become apparent from the subclaims and the following description of preferred embodiments of the present invention.

As already indicated above, it is known from the prior art to initiate countermeasures when resonances occur, e.g. to shut off the fuel injection for the internal combustion engine and / or also to actuate a parking flap, which prevents the supply of oxygen to the internal combustion engine.

It has been recognized that other events or effects may also create a high load on a vibration damping member in the driveline of a motor vehicle disposed between an internal combustion engine and a transmission of the drivetrain. The vibration damping member may be a torsional damper or a flywheel, in particular a dual mass flywheel as described above.

It may, for example, in the "stalling" of an internal combustion engine by under braking with gear engaged and clutch closed a high load on the vibration damping member act by the abrupt stopping of the internal combustion engine and the subsequent dragging of the internal combustion engine by the drive wheels, the transmission and thus over the vibration damping member driving the internal combustion engine occurs. Even when suddenly switching on or off an injection of fuel into the internal combustion engine, high loads can occur, since the angular momentum of the internal combustion engine and the angular momentum of the gear wheels driven by the drive differ greatly. Accordingly strong are the forces acting on the side of the internal combustion engine and from the side of the transmission to the vibration damping member.

In addition, there is a high speed gradient between the internal combustion engine side and the transmission side of the vibration damping both in the switch and in the Abschaltfall the internal combustion engine, for example. By switching on and off the fuel injection and concomitant on or off the combustion of the internal combustion engine.

If, for example, the motor vehicle is in motion when the switch-off event occurs, the drive train is typically biased by the drive through the internal combustion engine. If the internal combustion engine is switched off, e.g. by switching off the injection, as is known from the prior art, or by "stalling" the internal combustion engine by braking with gear and clutch engaged, the transition from the train to the pushing state of the motor vehicle leads to said high speed gradient at the vibration damping element because the rotational speed of the internal combustion engine differs greatly from the transmission-side rotational speed, which is generated by the sliding motor vehicle via the drive wheels. The higher the drag torque generated by the internal combustion engine in this case and the stronger the bias of the drive train, the higher the load that acts on the vibration damping member when the internal combustion engine is switched off. The same applies to the switch-on case.

Accordingly, some embodiments relate to a method of controlling an internal combustion engine of a powertrain of a motor vehicle, the powertrain having the internal combustion engine, a transmission, and a vibration damping member coupled between the internal combustion engine and the transmission. As mentioned, the vibration damping member may be a torsion damper or a flywheel, in particular a dual mass flywheel, or the like.

Typically, the vibration damping member is coupled on a primary side to an output shaft of the internal combustion engine and on a secondary side to a transmission input shaft of the transmission. As mentioned earlier, the dual mass flywheel typically has a primary flywheel disposed toward the internal combustion engine and a secondary flywheel disposed toward the transmission. The primary and the secondary flywheel are connected to each other with spring-damper units and attenuate resulting vibrations in the drive train from.

The method includes determining a speed of the internal combustion engine. The speed can e.g. at a crankshaft of the internal combustion engine via a crankshaft sensor, which includes a sensor wheel, are determined. Depending on the embodiment, the crankshaft sensor may detect a crank angle of less than 10 °, such as e.g. 6 °, without the present invention being limited to these exemplary angle values.

The determination of the rotational speed can take place continuously and / or at certain predetermined time intervals. Accordingly, in some embodiments, a plurality of rotational speed values are determined, which, for example, represent a rotational speed profile.

The determined speed of the internal combustion engine or e.g. a speed curve is analyzed. The analysis of the speed will be explained in detail below. It can e.g. comprise the comparison of a determined speed with a threshold and / or e.g. the analysis of a speed curve and the determination of speed oscillations and / or speed amplitudes or speed oscillation amplitudes.

Based on the speed analysis, it is determined whether there is a predetermined load operating condition in which an undesirable load is applied from the driveline to the vibration damping member. As stated above, for example, turning on or off the internal combustion engine or occurring resonances may cause loads acting on the vibration damping member and such operating conditions may be a predetermined load operating condition.

If the predetermined load operating state is present, the internal combustion engine is controlled such that the torque of the internal combustion engine is changed ramp-shaped. The torque of the internal combustion engine generates the internal combustion engine through the combustion of fuel taking place in it.

By ramping the torque of the internal combustion engine loads can be reduced or even avoided, which act on the vibration damping member in the load operating state. If e.g. During a switch-on or switch-off operation of the internal combustion engine changes the torque ramped, so there is a soft transition from a train to a pushing operation, since the torque generated by the internal combustion engine changes slowly and not abruptly, as e.g. when switching off the fuel supply or when suddenly changing the fuel supply happens. In the case of present resonances can be left by a ramp-shaped change in the torque of the internal combustion engine, the resonance range and thus also the load on the vibration damping member can be reduced.

Due to the ramp-shaped change in the torque of the internal combustion engine and the above-mentioned high speed gradients are avoided because the internal combustion engine does not stop abruptly, but reduces its torque over a longer period of time or builds up in the reverse of switching over a longer period.

The ramp-shaped change can be predetermined by a defined characteristic curve, which is pre-stored or mathematically determined. The ramp-shaped change may be linear or else follow a higher-order function such as a quadratic or exponential function. In addition, in some embodiments, the ramping may also be dynamic, e.g. based on an input parameter, the torque change is determined. The ramp change may e.g. also be dependent on which gear is engaged in the transmission.

In some embodiments, the ramp change of the torque of the internal combustion engine is e.g. achieved by a corresponding change in the fuel supply to the internal combustion engine or a corresponding control of an injection of the fuel or by other suitable means.

The ramp-like change of the torque takes place in a significantly longer time interval than e.g. takes a fuel injection on or off, which typically takes less than 10 milliseconds. The ramp-like change of the torque occurs in this case e.g. over a period of 100 milliseconds or more, e.g. 200 milliseconds. While the present invention is not limited to any particular time period, the duration of the ramp change in the embodiments is significantly longer than that required for a typical fuel injection on or off cycle. For example, the duration of the ramp change may be twice, three times, ..., ten times, or any other multiple of the duration of a fuel injection cutoff period.

In some embodiments, the step of analyzing the determined speed includes comparing the detected speed with a predetermined speed threshold. The predetermined speed threshold value may be zero, for example, so that in the case of starting, in which the speed increases, the above steps are performed. However, the speed threshold value can also be, for example, an idling speed, and the above steps are carried out when the speed of the internal combustion engine falls below the idling speed. In some embodiments, the comparison with the speed threshold also takes into account a hysteresis of the determined Speed, so that, for example, not every time the procedure is carried out when the determined speed falls below the speed threshold, but only if the speed for a certain period of time is below the speed threshold. This is helpful in some embodiments, since, for example, the idle speed of the internal combustion engine can fluctuate and, for example, by switching on a power consumer or by another event briefly fall below the idle speed. In such a case, it is not necessary to reduce the torque of the internal combustion engine, which can be prevented by the hysteresis.

In some embodiments, the predetermined load operating condition includes a power-on operation of the internal combustion engine, typically a starting operation or a re-engagement operation, and the torque of the internal combustion engine is ramped up. As stated above, the turn-on operation can be achieved by exceeding a determined speed of a predetermined speed threshold, e.g. is equal to zero or another low speed. As mentioned, by the ramp-shaped increase in the torque at a switch-on of the internal combustion engine occurring loads for the vibration damper member can be reduced.

In some embodiments, the predetermined load operating state comprises a shutdown operation of the internal combustion engine and the torque of the internal combustion engine is reduced in a ramp. As stated above, the turn-off operation can be recognized by the fact that a determined speed falls below a predetermined speed threshold value, e.g. the idling speed of the internal combustion engine falls. Characterized in that the torque of the internal combustion engine is ramped, occurring loads for the vibration damper member can be reduced even in a shutdown of the internal combustion engine.

In some embodiments, the predetermined load operating state includes a state in which speed vibration amplitudes (also called speed amplitudes) occur at the speeds of the internal combustion engine, which are above a predetermined amplitude threshold. Such speed vibration amplitudes typically occur when resonance occurs in the driveline, which can cause a high load on the vibration damper member. In order to detect such a load operating state, the analysis of the determined rotational speed of the internal combustion engine may comprise analyzing a curve of a plurality of determined rotational speeds, wherein the course of the rotational speeds determines rotational vibration amplitudes and the presence of the predetermined load state is determined, if a rotational speed amplitude above the predetermined amplitude threshold lies.

In some embodiments, a slope of the ramp change of the torque of the internal combustion engine is determined based on a current torque of the internal combustion engine. In this case, e.g. the higher the actual torque, the greater the slope of the ramp change, and vice versa. Thus, depending on the current torque, the torque change can be adjusted so that e.g. at a high current torque, the torque is changed faster and thus the load on the vibration damper member is reduced faster than at a low current torque. At a low torque and the load on the vibration damper member is lower, so that in such cases, a ramp-like change can be made with a lower pitch.

In some embodiments, the torque of the internal combustion engine is changed by a predetermined torque value. Thereby, in a load operation state in which resonance occurs, the resonance range can be exited by decreasing the torque by the predetermined torque value. The torque is changed ramped until the torque is lowered by the predetermined torque value. If e.g. after lowering the torque by the predetermined torque value further determines that a determined speed amplitude is still above the predetermined speed amplitude threshold, the torque can be lowered by a further predetermined torque value. If, on the other hand, it is determined that a determined speed amplitude is below the predetermined speed amplitude threshold value, the torque can be maintained at the value reduced by the predetermined torque value. If the reduction of the torque does not bring success in the sense that e.g. If the speed amplitude drops below the speed amplitude threshold value, it is possible, for example, to fall short of the ascertained speed of a further speed threshold value, e.g. initiated a shutdown of the internal combustion engine, wherein the torque, as stated above, is ramped down. This speed threshold may be below the idle speed, e.g. at 400 revolutions per minute, without the present invention being limited thereto.

In some embodiments, a reduction in torque may be reversed if a particular one Event is present. This event may be, for example, that the determined speed again exceeds a speed threshold, for example, the idle speed, which was previously exceeded and has led to the reduction of torque. Alternatively, such an event may be that it is determined that the driveline is open. The open driveline can be determined, for example, by a signal from a clutch switch, which emits a signal when the clutch is actuated / is. In an open driveline, the loads described above typically do not act on the vibration damper member. In such cases, the torque may be ramped up again to the initial value it had before the previous reduction. In some embodiments, the same function or characteristic may be used for increasing the torque as for the reduction.

For the determination of the speed of the internal combustion engine, a modeled speed can also be used that is not influenced by vibrations of the drive train and / or in which such vibration influences are reduced. For example, from a wheel speed and the knowledge of an engaged gear, a speed of the internal combustion engine can be determined, the wheel speed is typically not or if only very slightly influenced by vibrations of the drive train. Alternatively, the speed determined, for example, by a crankshaft sensor or the like can also be smoothed by a filter so that influences of vibrations of the drive train are at least reduced even at such a rotational speed.

In addition, in some embodiments, one or more measures may be taken to assist the shutdown process of the internal combustion engine, such as e.g. opening a decompression valve that causes decompression in a cylinder of the internal combustion engine or other cylinder-selective shutdown mechanisms.

Some embodiments relate to a motor vehicle having a driveline having an internal combustion engine, a transmission, and a vibration damping member coupled between the internal combustion engine and the transmission, as set forth above. The motor vehicle further comprises a controller, wherein the controller is adapted to at least partially carry out the method described above.

The controller may include other controllers or controls, such as those shown in FIG. a control element for the engine control (injection), controls for controlling the clutch, the transmission, etc. Since the control of the individual components of a motor vehicle is basically known, a detailed description of the control and its components is not required.

In addition, the controller may be coupled to different sensors, e.g. a speed sensor which is designed as a crankshaft sensor, and / or a wheel speed sensor which measures the wheel speed of a drive wheel, etc. The controller can receive signals from the speed sensor and determine therefrom a corresponding speed for the internal combustion engine, as also stated above.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

1 schematically shows an embodiment of a motor vehicle with a drive train and a controller;

2 schematically an embodiment of a shutdown process for the internal combustion engine of the drive train of the motor vehicle of 1 shows;

3 schematically an embodiment of a starting process for the internal combustion engine of the drive train of the motor vehicle of 1 shows; and

4 schematically an embodiment of a torque reduction for the internal combustion engine of the drive train of the motor vehicle of 1 shows;

An embodiment of a motor vehicle 1 is in 1 illustrated and the method described above will be described below with reference to the 2 to 4 explained.

The car 1 has a drive train 2 in which an internal combustion engine 3 , a dual-mass flywheel 4 , a clutch 5 and a gearbox 6 coupled with each other and it has a controller 12 Essentially adapted to the one described herein and below in connection with the 2 to 4 explained method at least partially executed.

The internal combustion engine 3 is designed here as a diesel engine with four cylinders and has a fuel injection with the control 12 connected via a connecting line.

The dual mass flywheel 4 has a primary flywheel 4a , which forms the primary mass and the internal combustion engine 3 is arranged and a secondary flywheel 4b that forms the secondary mass and to the clutch 5 and the transmission 6 is arranged. The primary flywheel 4a and the secondary flywheel 4b are via a spring element 4c mechanically coupled to each other, so that vibrations in the drive train 2 occur from the dual mass flywheel 4 be recorded.

The primary flywheel 4a is with a crankshaft 8th the internal combustion engine 3 coupled and the secondary flywheel 4b is about a shaft with the clutch 5 coupled. The coupling 5 is in turn via a transmission input shaft 9 with the gearbox 6 coupled. The gear 6 is on its output side via a drive shaft 10 with two drive wheels 11a and 11b coupled. The dual mass flywheel 4 is between the internal combustion engine 3 and the rest of the driveline 2 arranged out of clutch 5 , Transmission 6 and drive wheels 11a and 11 with the associated shafts, namely the transmission input shaft 9 and the drive shaft 10 and other unexplained parts of the drive train 2 is formed.

For measuring the speed of the internal combustion engine 3 is a speed sensor 7 provided the rotation of the crankshaft 8th detects and from this a speed of the internal combustion engine 3 determined. The speed sensor 7 Here is a rotation of the crankshaft 8th detect an angle of 6 °, so that depending on the speed of the internal combustion engine, a temporal resolution in the range of about 10 milliseconds is given for the detection of the speed. The speed sensor 7 transmits the determined speed values to the controller 12 he is connected to.

Alternatively or additionally, a wheel speed sensor 14 be provided, the one wheel speed to the controller 12 transmitted via an appropriate connection line. The control 12 may be from the wheel speed of the drive wheel 11a and one in the transmission 6 engaged gear a speed of the internal combustion engine 3 determine the gear 6 the engaged gear via a connecting line to the controller 12 transmitted.

It is also on the clutch 5 a clutch switch 13 provided, which is an actuation of the clutch 5 and thus an opening of the drive train 2 determined and this via a connection line to the controller 12 transfers.

The control 12 Although here is shown as a single control, but this is purely schematic to understand. The same applies to the connections to the internal combustion engine 2 , the speed sensor 7 , the clutch switch 13 and the wheel speed sensor 14 , which are also to be understood schematically as logical connections. The actual realization of the connections and the control 12 is not limited to the present embodiment, but includes all common in the automotive field embodiments.

2 shows an embodiment in which during a shutdown, the torque of the internal combustion engine 3 is reduced in a ramp. 2 illustrates on the abscissa the time "t" and on the ordinate in the upper region of a determined speed "D" of the internal combustion engine 3 and in the lower region a torque "M" of the internal combustion engine 3 ,

Before a time t0, the motor vehicle is in a normal operating state, in which the internal combustion engine 3 provides a constant torque M and the speed D is almost constant and only slightly oscillates. The vibrations are from the dual mass flywheel 4 attenuated.

At a time t0, the controller determines 12 in that the speed D has dropped below a speed threshold value Dmin1, for example by braking the motor vehicle 1 when the gear is engaged and in a load operating state, in which the internal combustion engine 3 possibly switched off. The speed threshold value Dmin1 here corresponds, for example, to the idling speed of the internal combustion engine 3 and is, for example, at 900 1 / min.

Accordingly, the controller controls 12 the fuel injection of the internal combustion engine 3 from the time t0 such that the torque M of the internal combustion engine via a linear characteristic (ramp) 21 between the time t0 and a later time 1 is continuously reduced to zero torque. At the same time, the engine speed D of the internal combustion engine also decreases over a linear speed curve 20 from the speed threshold Dmin1 to a zero speed reached at the time t1. The time interval between t0 and t1 is here, for example, 150 milliseconds and the torque has been reduced between t0 and t1 by a torque amount of ΔM1. The torque amount ΔM1 here corresponds to the torque change of the internal combustion engine at the time t0 at the idling speed Dmin1 and the torque value from zero at the time t1 at which the internal combustion engine 3 is completely stopped.

3 shows an embodiment in which at a switch-on the torque of the internal combustion engine 3 ramped is increased. 3 illustrates on the abscissa the time "t" and on the ordinate in the upper region of a determined speed "D" of the internal combustion engine 3 and in the lower region a torque "M" of the internal combustion engine 3 ,

Before a time t0, the motor vehicle is in a switched-off operating state, in which the internal combustion engine 3 no torque M supplies and the speed D is zero.

The internal combustion engine 3 is turned on and at a time t0 determines the controller 12 in that speed D has increased above a speed threshold value Dmin2 and is consequently in a load operating state in which the internal combustion engine is switched on. The speed threshold Dmin2 here is for example 100 1 / min, but can of course be at a different value below or above.

Accordingly, the controller controls 12 the fuel injection of the internal combustion engine 3 from the time t0 such that the torque M of the internal combustion engine via a linear characteristic (ramp) 23 between the time t0 and a later time 1 is continuously increased until the same time in a linear speed curve 22 increasing speed has reached an upper speed threshold Dmax1,

which is in the present example at the idling speed of 900 1 / min, without that the present invention is limited thereto.

Upon reaching the upper speed threshold Dmax1 at time t1, the control ends 12 in order to increase the torque M ramp-shaped and the internal combustion engine 3 goes into a normal operating state in which it delivers a constant torque M after time t1.

The time interval between t0 and t1 is here, for example, 150 milliseconds and the torque has been increased between t0 and t1 by a torque amount of ΔM2.

4 shows an embodiment in which speed oscillations of the internal combustion engine 3 be observed and the torque of the internal combustion engine 3 is reduced by a predetermined torque value ΔM3 when an allowable speed amplitude is exceeded. 4 illustrates on the abscissa the time "t" and on the ordinate in the upper region of a determined speed "D" of the internal combustion engine 3 and in the lower region a torque "M" of the internal combustion engine 3 ,

The control 12 For example, a speed vibration analysis may begin when the speed falls below a speed threshold, such as idle speed (see Dmin1 in FIG 2 ) and / or when a certain gear is engaged, etc.

First, the motor vehicle 1 at a time t0 in a normal operating condition and the speed D oscillating at a normal amplitude which is within a maximum allowable amplitude band Amax. The internal combustion engine 3 provides a constant torque M.

At a time t0, the controller determines that the rotational speed is a vibration amplitude 24 has reached, which exceeds the amplitude band Amax both at the upper and at the lower limit and thus is in a load operating state, in the resonances in the drive train 2 may occur. Accordingly, the control reduces the torque M of the internal combustion engine from the time t0 3 by a predetermined torque amount ΔM3 (also called offset). The reduction of the torque M takes place ramp-like over a linear course 25 until a time t1. At time t1, the speed oscillation amplitude is 24 again in the amplitude band Amax.

Accordingly, at the time t1, the change of the torque M of the internal combustion engine ends.

Should the controller 12 recognize that there is again an operating state, which allows to increase the torque M to the initial value, so increases the control 12 the torque M ramped by the amount of torque ΔM3, eg analogous to the ramp curve 25 only with mirrored slope. This is the case, for example, when the speed is again above the speed threshold of the idle speed or when the controller 12 based on a signal from the clutch switch 13 recognizes that the drivetrain 2 is open.

As already stated above, it may also occur after the reduction of the torque M, that the oscillation amplitude 24 still outside the allowable amplitude range Amax. In such a case, the controller can 12 again reduce the torque by a torque amount, for example, the amount of torque ΔM3 ramp. If the speed falls below a further speed threshold value, which can be, for example, 400 rpm, then so can the shutdown process, such as in connection with 2 was declared to be performed.

In the above embodiments, a linear characteristic has been used for the ramp-shaped change of the torque, for example, in the controller 12 is stored. As already stated above, the slope of the characteristic curve may depend on the magnitude of an output torque and / or on an engaged gear. In addition, the magnitude of the amount by which the torque is changed may also depend on an output torque, an engaged gear, and / or how much the speed amplitude is above the allowable amplitude value.

The above embodiments may be implemented individually or in any combination.

LIST OF REFERENCE NUMBERS

1

motor vehicle

2

drive train

3

Internal combustion engine

4

Dual mass flywheel (vibration damping element)

4a

primary flywheel

4b

secondary flywheel

4c

spring element

5

clutch

6

transmission

7

Speed sensor

8th

crankshaft

9

gear shaft

10

drive shaft

11a, b

drive wheels

12

control

13

clutch switch

14

wheel speed sensor

20

Speed curve when switching off

21

ramped torque change at shutdown

22

Speed curve when switching on

23

ramped torque change at power up

24

Speed vibration

25

ramped torque change by a predetermined amount

Amax

 amplitude threshold

D

rotation speed

Dmin1

 Speed threshold (idle speed) for shutdown case

d min 2

 Speed threshold (idling speed) for switch-on event

Dmax1

 Speed threshold (idling speed) for switch-on event

ΔM1

Torque change shutdown case

ΔM2

Torque change switch-on case

ΔM3

Torque change preset amount

M

torque

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 102009019081 B4 [0006]
• EP 2071163 A2 [0007]

Claims (10)

Method for controlling an internal combustion engine ( 3 ) of a drive train ( 2 ) of a motor vehicle ( 1 ), whereby the drive train ( 2 ) an internal combustion engine ( 3 ), a transmission ( 6 ) and a vibration damping member ( 4 ), which between the internal combustion engine ( 3 ) and the transmission ( 6 ), characterized by the steps of: determining a rotational speed of the internal combustion engine ( 3 ); Analyzing the determined rotational speed of the internal combustion engine; Determining, based on the speed analysis, whether there is a predetermined load operating condition in which an undesirable load from the driveline ( 2 ) on the vibration damping member ( 4 ) is exercised; and if the predetermined load operating condition exists, controlling the internal combustion engine ( 3 ) such that the torque of the internal combustion engine ( 3 ) is changed ramp-shaped.  The method of claim 1, wherein the step of analyzing the determined speed comprises comparing the detected speed with a predetermined speed threshold (Dmin1, Dmin2, Dmax1). Method according to one of the preceding claims, wherein the predetermined load operating state a switch-on of the internal combustion engine ( 3 ) and the torque of the internal combustion engine ( 3 ) is ramped. Method according to one of the preceding claims, wherein the predetermined load operating state a shutdown operation of the internal combustion engine ( 3 ) and the torque of the internal combustion engine ( 3 ) is reduced in a ramp. Method according to one of the preceding claims, wherein the predetermined load operating state comprises a state in which speed oscillation amplitudes ( 24 ) occur which are above a predetermined amplitude threshold (Amax). The method of claim 5, wherein analyzing the determined speed of the internal combustion engine ( 3 ) comprises analyzing a course from a plurality of determined rotational speeds, rotational speed amplitudes being determined from the course of the rotational speeds ( 24 ) and the presence of the predetermined load condition is determined when a speed oscillation amplitude ( 24 ) is above the predetermined amplitude threshold (Amax). Method according to one of the preceding claims, wherein a slope of the ramp-shaped change of the torque of the internal combustion engine ( 3 ) is determined based on a current torque of the internal combustion engine. Method according to one of the preceding claims, wherein the torque of the internal combustion engine ( 3 ) is changed by a predetermined torque value (ΔM3). Method according to one of the preceding claims, wherein it is additionally determined whether the drive train ( 2 ) is open. Motor vehicle with a drive train ( 2 ), which is an internal combustion engine ( 3 ), a transmission ( 6 ) and a vibration damping member ( 4 ), which between the internal combustion engine ( 3 ) and the transmission ( 6 ) and with a controller ( 12 ), whereby the controller ( 12 ) is adapted to carry out the method according to one of the preceding claims.

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