DE102016206591A1 - Method and device for controlling an internal combustion engine - Google Patents

Abstract

Method for controlling an automated clutch (20) in a drive train of a motor vehicle (1), characterized in that the opened clutch (20) is closed when an input speed (n) of a transmission (30) exceeds a predefinable sail breakage speed (nmaxcont).

Description

State of the art

From the DE 10 2013 215 101 A1 a method for engaging a drive motor to a drive train is known in which a speed difference (ndiff) between an input side and an output side of a clutch is determined and then the clutch is controlled by specifying a target clutch torque to be transmitted depending on the speed difference.

Disclosure of the invention

The method with the features of independent claim 1, in which an open automated clutch is closed in a motor vehicle, when the input speed exceeds a predetermined sail breakage speed in contrast, especially when used in a motor vehicle has the advantage that sailing times, ie times during which the clutch is open and an internal combustion engine can be switched off or operated at idle speed, can be maximized and at the same time a driving dynamics can be upheld. At the same time the driver intuitive intervention options remain in the behavior of the motor vehicle.

By maximizing the proportion of sail, fuel can be saved and emissions reduced. By reducing the number of sailing phases results in a reduction of the clutch wear by less frequent closing operations.

Namely, it may be provided in such a method that the sailing mode, so the rolling of the motor vehicle with the clutch open, is terminated when an actuation of an accelerator pedal is detected. If the input speed of the clutch then too high, the speed of the engine-side crankshaft (which is, for example, when the clutch is open or rotates at idle speed) must first be raised to the input speed, which can be both acoustically uncomfortable at high input speed and uncomfortable take long. The sail breakage speed can be selected in particular depending on a currently engaged or a gear engaged at the time of opening the clutch.

Furthermore, it is possible that the driver of the motor vehicle wishes to express by switching to a lower gear that he wishes an engine braking intervention of the motor vehicle. By the method with the features of independent claim 1 can be particularly easy to achieve an expected behavior of the motor vehicle.

It may be provided here that the clutch is then closed when the input speed drops when the clutch is initially below the sail breakage speed and then exceeds it again. That The clutch is continuously open during the fall below the sail breakage speed until it is exceeded again.

This has the advantage that in the event that the gear engaged in the gear is changed to a lower gear, can cover particularly well, i. that long sailing phases and comfortable ending of the sailing phase can be arranged particularly well.

In a further aspect it can be provided that the clutch is closed even when the input speed falls below a predefinable minimum speed. The minimum speed is suitably lower than the sail break speed. This can be prevented that the speed of the crankshaft is lower than the idle speed, which would be uncomfortable at a restart of the internal combustion engine. The minimum speed can be selected as low as possible to allow as long as possible a sailing of the motor vehicle.

In a further aspect, it can be provided that a driver of the motor vehicle is indicated to switch to a lower gear when the input rotational speed falls below a predefinable interaction rotational speed. The interaction speed is suitably higher than the minimum speed and optionally lower than the sail break speed. In this way, it can be acted on in a particularly simple manner that a currently engaged gear is chosen so that a closing of the clutch and a corresponding synchronization of the rotational speed of the crankshaft with the input speed is particularly well possible. Advantageously, interaction speed and skip rotation speed may be tuned to the gear ratio of the transmission such that downshifting by one gear and the concomitant increase in input speed will not result in the sail skip speed being exceeded if this downshift is performed at an input speed less than or equal to the interaction speed. Thus, unnecessary interruption of the sailing phase are avoided by the gear change. This can avoid interference of an internal combustion engine and / or an electric motor for speed synchronization and thus leads to further fuel economy. For this purpose, it makes sense if sail breakage speed and / or interaction speed can be specified depending on the gear engaged.

In another aspect, it may be provided that the automated clutch (before clutch closure) is opened depending on the input speed of the transmission when the input speed falls below a maximum speed. The maximum speed is expediently higher than the minimum speed, and / or higher than the sail break speed and / or higher than the interaction speed. It is possible, for example, that the maximum speed is selected depending on the gear. For example, the sail breaking speed for a particular gear may always be selected so that it corresponds to the maximum speed of the next lower gear - in this way can be achieved in a particularly simple manner clearly predictable for the driver behavior of the motor vehicle.

In particular, it may be provided that the clutch is closed again when the input speed exceeds the maximum speed again. Hereby can be prevented in a particularly simple manner that the synchronization of the input speed with the speed of the crankshaft after closing the clutch is perceived as uncomfortable.

In a further aspect, it can be provided that the internal combustion engine of the motor vehicle is switched off when the clutch is open. This mode of operation is also referred to as "engine stoppage sailing".

In a further aspect it can be provided that the internal combustion engine of the motor vehicle is operated with the clutch open at a predeterminable speed, in particular at an idling speed. This mode of operation is also referred to as "idle sailing".

The invention can be carried out both in connection with engine stoppage sails and in conjunction with idling sails.

In another aspect, it can be provided that the internal combustion engine of the motor vehicle after closing the clutch in a coasting operation, ie with overrun fuel cutoff, i. operated with shut off injection and / or ignition. In particular, it can be provided that the internal combustion engine is then operated in overrun mode when the accelerator pedal is not actuated and the input rotational speed has exceeded the sail abort speed. In this way, a predictable system behavior can be achieved particularly easily.

In further aspects, it may be provided that the input speed is determined as a function of a gear selection information and a vehicle speed. That The input speed is determined depending on which gear is currently engaged. The vehicle speed here is a measure of a wheel speed of the motor vehicle.

In other aspects, the invention relates to apparatuses adapted to carry out the method, in particular a computer program, a machine-readable storage medium and a control unit.

Hereinafter, embodiments of the invention will be explained in more detail with reference to the accompanying drawings. In the drawing show:

1 a system in which the method according to the invention can be used;

2 a flowchart of the method according to one aspect of the invention;

3 - 7 exemplary curves of the input speed.

1 shows a motor vehicle 1 with an internal combustion engine 10 whose crankshaft has a clutch 20 with a manual transmission 30 connected is. By the rotation of the crankshaft in a known manner drive wheels 40 driven.

Between coupling 20 and manual transmission 30 rotates the crankshaft with the input speed. This can, for example, with a speed sensor 25 be recorded. A control unit 50 can be provided, the measured values of the speed sensor 25 to receive and via an actuator (not shown) the clutch 20 to open or close. The control unit 50 has a machine-readable storage medium 51 on which a computer program can be stored, which is set up to carry out the method according to the invention.

The speed sensor 25 can also be between manual transmission 30 and wheel 40 or at the wheel 40 be attached and a speed of the wheel 40 to capture. Is then an information about the currently in the manual transmission 30 engaged gear available (for example via a sensor in shift lanes of the gear selector lever), the input speed can also be determined from the speed of the wheel and associated with the currently selected gear ratio.

2 shows by way of example the sequence of the method, as for example by the control unit 50 is performed. The procedure begins in step 1000 in which the internal combustion engine is in overrun operation, for example. The sail break speed nmaxcont and the maximum speed nmax are set. For example, predefinable values can be specified, but it is also possible that an engaged gear of the transmission 30 is determined and dependent on this engaged gear, the sail break speed nmaxcont and / or the maximum speed nmax is set.

It follows step 1010 in which the input side of the transmission 30 incoming input speed n of the crankshaft is determined. It can be checked whether the input speed n is smaller than the maximum speed nmax. Once this is the case, follow step 1030 , Alternatively, in step 1010 also be checked whether a control element was actuated to initiate the sailing operation, and in this case to step 1030 be branched. This actuation of the operating element can be, for example, that both the accelerator pedal and a brake pedal of the motor vehicle 1 not be operated. It can also consist in pressing a button.

In step 1030 will the clutch 20 opened, and the internal combustion engine 10 either switched off or continued with a predefinable speed. The predeterminable speed may for example be selected equal to an idle speed. It follows step 1040 ,

In step 1040 it is checked whether the input speed n is smaller than the sail break speed nmaxcont. Once this is the case, follow step 1050 ,

In step 1050 it is checked whether the input speed n has become greater again than the sail break speed nmaxcont. If this is the case, follow step 1060 otherwise step follows 1070 ,

In step 1060 will the clutch 20 closed. Optionally, it may be provided that before closing the clutch 20 a speed of the internal combustion engine 10 is accelerated to the value of the input speed n, for example, by injecting fuel and igniting the resulting fuel / air mixture or by appropriate control of a coupled to the crankshaft electric machine. It can be provided that the internal combustion engine 10 after closing the clutch 20 operated in overrun to achieve a braking effect.

In the optional step 1070 it is checked whether the input speed n is smaller than the interaction speed nhmi. If this is the case, follow step 1080 otherwise it will be branched back to step 1070 , Will step on 1070 renounced, immediately becomes step 1090 further branched.

In step 1080 a message is issued to switch back a gear. This message can be displayed to the driver of the motor vehicle, for example by an optical signal in a combination instrument, or by an acoustic signal, or by a haptic signal such as by a vibration of the gear selector lever. It follows step 1090 ,

In the optional step 1090 it is checked whether the input speed n is smaller than the minimum speed nmin. If this is the case, follow step 1100 otherwise it will be traced back to step 1040 , Will step on 1090 renounced, instead of step 1090 immediately step 1050 called.

In step 1100 is optionally the speed of the internal combustion engine 10 synchronized with the input speed n and then the clutch 20 closed. Subsequently, it is possible that the internal combustion engine 10 is operated in overrun, but it is also possible that the internal combustion engine 10 is operated fired and, for example, with a fixed speed, in particular the idle speed, operated.

This ends the procedure. Throughout the procedure it can be provided that it is checked whether an accelerator pedal is actuated. If this is the case, then optionally the speed of the internal combustion engine 10 synchronized with the input speed n, the clutch 20 closed and the internal combustion engine 20 driven according to a degree of actuation of the accelerator pedal to the motor vehicle 1 to accelerate.

During the entire process, provision may also be made for checking whether a brake pedal is actuated. If this is the case, optionally the speed of the internal combustion engine 10 synchronized with the input speed n and then the clutch 20 getting closed. This closing procedure with previous speed synchronization is particularly comfortable and leads to particularly low clutch wear. Alternatively, by first closing the clutch 20 directly the speed of the internal combustion engine 10 be synchronized with the input speed n without applying the necessary acceleration work by an internal combustion engine or an electric motor. This process is particularly energy efficient. Mixed forms with a partial synchronization of the input speed n are also possible.

It will be understood by those skilled in the art that the method may be implemented in software, or in hardware, or in a hybrid of software and hardware.

3 shows an exemplary first curve of the input speed n. The input speed n falls at time t0 below the maximum speed nmax. The coupling 20 is opened and the internal combustion engine 10 is turned off, for example. At time t1, the input speed n falls below the minimum speed nmin. The coupling 20 is closed and the internal combustion engine 10 operated so that the input speed n approximately assumes a constant value nmin.

4 shows an exemplary second curve of the input speed n. The input speed n falls at time t0 below the maximum speed nmax. The coupling 20 is opened and the internal combustion engine 10 is turned off, for example. The input speed n falls below the sail breakage speed nmaxcont before time t1. At time t1, the driver of the motor vehicle switches 1 a gear back. The input speed n increases and exceeds the sail break speed nmaxcont. The internal combustion engine 10 is started, the clutch 20 closed and internal combustion engine 10 operated in overrun mode. In the example shown, the motor vehicle travels 1 from this point on a sloping road, so that the input speed n increases slightly.

5 shows an exemplary third curve of the input speed n. The input speed n falls at time t0 below the maximum speed nmax. The coupling 20 is opened and the internal combustion engine 10 is turned off, for example. The input speed n falls before the time t2 below the sail break speed nmaxcont and at time t2 below the interaction speed nhmi. The driver of the motor vehicle 1 is displayed to switch back a gear. At time t1, the driver switches back a gear, so that the input speed n increases. However, the input speed n remains lower than the sail break speed nmaxcont, so the clutch 20 remains open and the sailing operation is continued.

6 shows an exemplary fourth course of the input speed n. In contrast to in 5 the driver switches back by two gears at time t1. Due to the associated larger jump of the input speed n, this exceeds the sail breakage speed nmaxcont. The coupling 20 is closed and the vehicle 1 operated in overrun mode.

7 shows an exemplary fifth curve of the input speed n. The input speed n falls at time t0 below the maximum speed nmax. The coupling 20 is opened and the internal combustion engine 10 is turned off, for example. At time t1, the driver of the motor vehicle switches 1 a gear back, and the input speed n exceeds the maximum speed nmax again. The coupling 20 is closed again and the motor vehicle 1 is operated again in overrun mode.

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 102013215101 A1 [0001]

Claims (15)

Method for controlling an automated clutch ( 20 ) in a drive train of a motor vehicle ( 1 ), characterized in that the opened coupling ( 20 ) is closed when an input speed (n) of a transmission ( 30 ) exceeds a predefinable sail breakage speed (nmaxcont). Method according to claim 1, wherein the coupling ( 20 ) is then closed when the input speed (s) initially drops below the sail break speed (nmaxcont) and then exceeds again. Method according to claim 1 or 2, wherein the coupling ( 20 ) is closed even if the input speed (n) falls below a predetermined minimum speed (nmin). Method according to one of the preceding claims, wherein a driver of the motor vehicle ( 1 ) is displayed, to shift to a lower gear when the input speed (n) falls below a predeterminable interaction speed (nhmi). Method according to one of the preceding claims, wherein the coupling ( 20 ) is opened when the input speed (n) drops below a maximum speed (nmax). Method according to claim 5, wherein the coupling ( 20 ) is closed again when the input speed (n) again exceeds the maximum speed (nmax). Method according to one of claims 1 to 6, wherein sail breaking speed (nmaxcont) and / or maximum speed (nmax) are selected depending on a currently engaged gear. Method according to one of the preceding claims, wherein an internal combustion engine ( 10 ) of the motor vehicle ( 1 ) with the clutch open ( 20 ) is switched off. Method according to one of claims 1 to 7, wherein an internal combustion engine ( 10 ) of the motor vehicle ( 1 ) with the clutch open ( 20 ) is operated at an idle speed. Method according to one of the preceding claims, wherein an internal combustion engine ( 10 ) of the motor vehicle ( 1 ) after closing the clutch ( 20 ) is operated in a pushing operation. Method according to one of the preceding claims, wherein the input speed (n) by means of a speed sensor ( 25 ) is determined. Method according to one of claims 1 to 11 wherein the input speed (n) is determined depending on a gear selection information and a vehicle speed. Computer program adapted to carry out the method according to one of claims 1 to 12. Machine-readable storage medium ( 51 ) on which the computer program according to claim 13 is stored. Control and / or regulating device ( 50 ) arranged to carry out the method according to one of claims 1 to 12.

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