DE102004051427A1 - Internal combustion engine operating method, involves adjusting one of three adjusting units that is not failed in case of failure of one unit so that standard adjustment range of unit is shifted into changed fail-safe adjustment range - Google Patents

Abstract

The method involves using three adjusting units (1-3) in an internal combustion engine, where one of the adjusting units is used for adjusting and/or influencing a lift of a gas exchange valve. One of the adjusting units that is not failed is adjusted in case of the failure of one of the adjusting units, such that the standard adjustment range of the adjusting unit is shifted into the changed fail-safe adjustment range.

Description

Field of the invention

The The invention relates to a method for operating an internal combustion engine in emergency operation, wherein the internal combustion engine first adjustment means in the form of an intake camshaft adjuster, second adjusting means in the form of an exhaust cam phaser and third adjusting means in the form of means for adjusting or influencing the stroke having the gas exchange valves.

Internal combustion engines are usually equipped with camshaft adjusters, s. for example the DE 103 44 816 A1 in which a relative rotation can be made between an inner rotor connected to the camshaft and an outer rotor operatively connected to the crankshaft. When adjusting the inner rotor relative to the outer rotor between an "early stop" and a "late stop", the timing of the gas exchange valves are affected. For each of the intake camshaft and the exhaust camshaft a camshaft adjuster can be provided.

Next hydraulic adjusters are also electrically operated devices common.

Similarly, it is known that the internal combustion engine is equipped with means for adjusting or influencing the stroke of the gas exchange valves (Hubumschalter). Such agents are for example in the DE 101 56 309 A1 and in the US 4,796,573 described. The means are suitable for generating an additional valve lift in addition to the opening stroke of the lift valve caused by the shape of the cam of the camshaft. For this purpose, a force application device is often acted upon with hydraulic fluid, which can be done in such a way that a largely variably influenced valve lift is present.

With in such a way equipped internal combustion engine can - under specification of known characteristic fields - an optimal Operation can be achieved.

Around ensure a safe engine start too can, have to The elements of the engine system in certain relative positions to each other. In particular, the position of the intake camshaft to the crankshaft and that of the exhaust camshaft to the crankshaft and the position of the inlet to the exhaust camshaft in one certain ratio to ensure optimum operation. The same applies to the operation of the Gas exchange valves, d. H. It is important if the means of influencing the stroke of the gas exchange valves are set to "large" stroke or "small" stroke.

While it possible during normal operation of the engine is, the camshafts when stopping the engine regulated in one Base position to proceed, where they by means of a locking element can be fixed and also the valve lift for the next Engine start can be adjusted, are the camshafts when "stalling" the engine in one Undefined position and also the valves are for the next engine start possibly in the wrong position. This can cause problems if the engine should be restarted.

Appropriate Problems are to be expected if one of the components fails, ie the intake camshaft adjuster, the exhaust camshaft adjuster or the means for adjusting or influencing the stroke of the Gas exchange valves. This can z. B. then be the case when an electric variable motor in one of the camshaft adjuster fails. It is in this case difficult or impossible, to continue to operate the internal combustion engine.

in the In the prior art, there are various approaches to the engine useful To help emergency running properties.

The DE 102 20 687 A1 describes a device for releasably connecting and adjusting the camshaft and the crankshaft of the engine, wherein a trained as a three-shaft gear adjusting gear is used, which has a crankshaft-connected drive shaft, a camshaft-connected output shaft and connected to an electric adjusting motor adjusting shaft. In this case, there is a stationary gear ratio between the input and output shafts when the adjusting shaft is stationary, the height of which determines the type of transmission and the direction of adjustment of the camshaft which has a basic or emergency running position. The reliability of the device described is improved in that in case of failure of the adjusting motor or its control by braking or setting the adjustment and by simultaneously rotating the drive shaft and by a suitable stationary gear ratio, the base or emergency position of the camshaft reach and durable.

The DE 102 57 706 A1 wants to create an electric camshaft adjuster, which adjusts the camshaft in case of failure of the adjusting motor or its control or power supply in a simple manner and de-energized in their Notlauf- or base position. For a structural design of an adjustment is provided so that stationary gear Translations can be realized by an early and a late base position of the camshaft can be achieved only by braking the adjusting of the variable. In this case, the deceleration of the adjusting shaft takes place by short-circuit braking of the adjusting motor.

The DE 102 24 446 A1 shows a device for relative angular displacement between two rotating, drive-connected elements, which are connected via a actuating shaft having a transmission member which is acted upon by a rotor of an electric actuator and the relative angular position is changed by changing its relative position to the rotating elements. In order to carry out the device for relative angular displacement between two rotating elements so that the actuator has a safe emergency operation, the actuating shaft is operatively connected to at least one of the rotating elements.

Other solutions are concerned with the question of how an emergency operation of an internal combustion engine can be achieved, including the DE 101 08 055 C1 proposes a method of controlling the machine. Similarly, the DE 41 25 677 A1 an emergency-capable control device for the internal combustion engine. Another solution of this kind comes from the DE 103 07 307 A1 out.

Of the The present invention is in the light of that discussed above Prior art, the object of a method of the above which it is possible to further improve To achieve emergency operation of the internal combustion engine and it also after the "stalling of the Motors' ensure that he can be started again.

The solution this object by the invention is characterized in that in the event of failure of one of the adjustment means - ie the first adjustment means in In the form of an intake camshaft adjuster, the second adjusting means in the form of an exhaust camshaft adjuster and the third adjusting means in the form of means for adjusting or influencing the stroke the gas exchange valves - the not failed adjustment means are adjusted so that the standard setting range of Setting means in a changed Emergency stop adjustment range is shifted to start and / or to allow an emergency operation of the internal combustion engine.

Of the So the essence of the invention is that it does not attempt to the failed adjustment in case of failure in a base position to bring what most solutions according to the state Provide the technique, but that is tried by adjusting the still intact setting in a changed operating condition the Compensate for malposition of the failed agent.

• a) dass beim Ausfall des ersten oder zweiten Einstellmittels die aktuelle Position der Einlassnockenwelle und der Auslassnockenwelle zur Kurbelwelle ermittelt wird,
• b) dass dann eine Prüfung erfolgt, ob eine Ventilüberschneidung zwischen einem vorgegebenen Minimalwert und einem vorgegebenen Maximalwert durch Verstellen des nicht ausgefallenen Einstellmittels einstellbar ist,
• c') dass dann im Falle dessen, dass dies möglich ist, eine Ventilüberschneidung zwischen dem vorgegebenen Minimalwert und dem vorgegebenen Maximalwert durch Verstellen des nicht ausgefallenen Einstellmittels eingestellt wird,
• c'') dass dann im Falle dessen, dass dies nicht möglich ist, eine minimal mögliche Ventilüberschneidung durch Verstellen des nicht ausgefallenen Einstellmittels eingestellt wird und
• d) dass dann die dritten Einstellmittel so eingestellt werden, dass sich ein größtmöglicher Hub der Gaswechselventile ergibt und
• e) dass schließlich das Starten und/oder der Notlaufbetrieb der Brennkraftmaschine mit den vorgenommenen Einstellungen erfolgt.

In particular, it is provided

• a) that the failure of the first or second adjusting means, the current position of the intake camshaft and the exhaust camshaft is determined to the crankshaft,
• b) that then a check is made as to whether a valve overlap between a predefined minimum value and a predefined maximum value can be set by adjusting the non-failed setting means,
• c ') that in the event that this is possible, a valve overlap between the predetermined minimum value and the predetermined maximum value is adjusted by adjusting the non-failed setting means,
• c '') that then in the event that this is not possible, a minimum possible valve overlap by adjusting the non-failed setting means is set and
• d) that then the third adjusting means are adjusted so that the largest possible stroke of the gas exchange valves results and
• e) that finally the starting and / or the emergency operation of the internal combustion engine takes place with the settings made.

• a) dass beim Ausfall der dritten Einstellmittel der aktuelle Hub der Gaswechselventile ermittelt wird,
• b) dass dann eine Ventilüberschneidung zwischen einem vorgegebenen Minimalwert und einem vorgegebenen Maximalwert durch Verstellen der nicht ausgefallenen ersten und zweiten Einstellmittel eingestellt wird und
• c) dass schließlich das Starten und/oder der Notlaufbetrieb der Brennkraftmaschine mit den vorgenommenen Einstellungen erfolgt.

With this procedure, the failure of one of the two camshaft adjuster can be countered. Another embodiment of the invention provides

• a) that the current stroke of the gas exchange valves is determined when the third setting means fails,
• b) that then a valve overlap between a predetermined minimum value and a predetermined maximum value by adjusting the non-failed first and second adjustment means is set, and
• c) finally that the starting and / or the emergency operation of the internal combustion engine takes place with the settings made.

Of the mentioned predetermined minimum value of the valve overlap is thereby preferably 0 °; the predetermined maximum value of the valve overlap is more advantageous Way 10 °.

Of the inventive proposal is especially used when as an intake camshaft adjuster and as exhaust camshaft adjuster electrically operated phasers be used.

The Means for adjusting or influencing the stroke of the gas exchange valves can preferably controlled in non-failure or regulated a small or a big one Adjust valve lift.

A Training provides that additional for the above procedure, at least one further motor parameter according to one predetermined algorithm is adapted to the emergency operation. at this parameter may be the idling speed, the injection timing and / or the ignition timing act.

With The proposed method makes it possible under certain circumstances the "stalling" of the engine again Starting or failure of one of the adjusting means for the camshaft or for the valves maintain an emergency operation to at least the next workshop to reach.

Short description the drawings

In the drawing is an embodiment of Invention shown. Show it:

1 only very schematically an internal combustion engine with an intake camshaft adjuster, an exhaust camshaft adjuster and means for adjusting or influencing the stroke of the gas exchange valves,

2 a flowchart for the procedure in case of failure of a camshaft adjuster and

3 a flow chart for the procedure when failure of the means for adjusting or influencing the valve lift.

Full Description of the drawings

In 1 is an internal combustion engine sketched, being one on a crankshaft 8th sitting piston 9 in a cylinder 10 is indicated. The crankshaft 8th is about a chain drive 11 respectively. 12 with an intake camshaft 6 or exhaust camshaft 7 in conjunction with a first phaser 1 or a second camshaft adjuster 2 for a relative rotation between crankshaft 8th and camshafts 6 . 7 can provide. At the camshaft adjusters 1 . 2 These are electrically operated systems where the torque from the crankshaft 8th via one three-shaft gearbox each on one camshaft 6 . 7 is transmitted. Conceivable usable three-shaft transmissions are, for example, swashplate transmissions, planetary, double planetary gear, Innenexzenter-, Doppelinnenexzentergetriebe, Wolfromgetriebe or the like.

The cams 13 . 14 the camshafts 6 . 7 operate the inlet valve 4 or the outlet valve 5 , where - only very schematically shown - means 3 ( 3 ' for the inlet valve 4 and 3 '' for the exhaust valve 5 ) are provided for influencing the valve lift (for example, switchable cam followers, such as switchable cup or roller tappets or switchable drag, rocker or rocker arm or the like, or movable space cam).

The camshaft adjuster 1 for the intake camshaft 6 , the camshaft adjuster 2 for the exhaust camshaft 7 and the funds 3 for the valve control are controlled by the engine control so that they work according to a predetermined map depending on various engine parameters.

In the case of one of the three adjustment means 1 . 2 or 3 fails, it is provided according to the invention that the non-failed adjustment means are adjusted so that the standard setting range of these means in which they normally work, is moved to a modified runflat adjustment range to allow starting and / or emergency operation of the internal combustion engine ,

The procedure then provided is exemplary for the failure of a camshaft adjuster 1 respectively. 2 in 2 shown. It is assumed that only one of the camshaft adjuster, so elements 1 or 2 fails, and that, moreover, remain the third adjusting means for Ventilhubeinstellen intact.

First of all, it must be stated by means of engine control or monitoring that one of the means 1 or 2 has failed, which can be done by appropriate sensors in a simple manner, ie it is first checked whether "adjusting 1 or 2 For this purpose, sensors or trigger marks can be provided on the camshafts and on the crankshaft, if this is not the case, ie if all adjustment means are intact, then the control of the internal combustion engine takes place according to normal operation and according to the stored characteristic map; Standard run "according to the" standard setting range ".

technological It turns out that it is particularly advantageous in idle, a small valve overlap and a big one Valve lift to have. Due to the small valve overlap when flowing in the new air-fuel mixture still exhaust particles in the combustion chamber, which leads to a better mixing lead the fresh air, but their share is not that big that it is a bad ignition or combustion comes. The big hub ensures that enough Fresh charge can flow into the combustion chamber.

For the embodiment, the typical scenario is assumed that the inletno ckenwellenversteller 1 its base position in "late" and the exhaust camshaft adjuster 2 has its base position in "early." This means that the valve overlap is smallest when both adjusters 1 . 2 in base position, ie it is possible that in this case there is no valve overlap. Falls the intake camshaft adjuster 1 in the early position and he stops there, ie it is no longer possible for him to adjust to "late", it is advantageous to the exhaust camshaft adjuster 2 to drive into the early position, since then in this case the valve overlap is the smallest. If no valve overlap exists in this constellation, it is possible to use the exhaust camshaft adjuster 2 to adjust some of the base position towards "late." All other positions of the exhaust cam phaser 2 lead to higher valve overlaps.

Will the failure of the camshaft adjuster 1 or the camshaft adjuster 2 detected, so first a position determination must be made to determine in which relative position the intake camshaft 6 (NW _E ), the exhaust camshaft 7 (NW _A ) and the crankshaft 8th (KW) are related to each other. In this case, a check is made whether an adjustment of the non-failed camshaft adjuster 1 respectively. 2 in such a way is possible that a valve overlap between 0 ° and 10 ° is present.

If this is possible, in the next step, such a valve overlap between 0 ° and 10 ° is set, with the not failed camshaft adjuster 1 respectively. 2 is adjusted accordingly.

If this is not possible, a minimum possible valve overlap is set, for which the non-failed camshaft adjuster 1 respectively. 2 is operated accordingly.

Subsequently, over the third setting means for Ventilhubeinstellen a maximum valve lift set.

This is the setting for the emergency operation, ie in this mode, the internal combustion engine is operated until the failed camshaft adjuster 1 respectively. 2 can be repaired or replaced.

The non-failed camshaft adjuster 1 . 2 actuated camshaft 6 . 7 can therefore be adjusted by means of the non-failed phaser in a position so that the engine despite undefined position of the failed camshaft adjuster can still be started. This position varies depending on the position of the failed camshaft adjuster. In the event of failure of a camshaft adjuster, the non-failed phaser can be moved into any position between the end stops of the phaser and also the valve stroke can be varied so that the overall result is a setting or position in which the engine remains bootable.

Basically it is also conceivable that for the explained If other positions are approached or a smaller or smaller valve lift is set. Furthermore, for example on the intake camshaft a smaller and on the exhaust camshaft a large Valve lift can be adjusted - or vice versa. Optimal operating conditions can be achieved by known thermodynamic Investigations are determined.

The planned procedure for the failure of the funds 3 for influencing the valve lift is in 3 also shown as a flow chart. It is assumed that the two camshaft adjuster 1 and 2 stay intact.

First, it should be noted from the engine control or monitoring that the means 3 failed, which is again done by appropriate sensors, ie it is first checked whether the "adjustment 3 If this is not the case, the control of the internal combustion engine takes place in accordance with normal operation and according to the stored characteristic map, that is, the "standard run" according to the "standard setting range" takes place.

Will the failure of the funds 3 detected, the current valve lift is detected, in which the valves after failure of the funds 3 are located.

In the example case according to 3 is used both in the case of a large valve lift and in the case of a small valve lift in which the means 3 failed, a valve overlap between 0 ° and 10 ° by the non-failed camshaft adjuster 1 and 2 set.

This is the emergency mode is reached, ie in this mode, the internal combustion engine is operated until the failed funds 3 can be repaired or replaced.

In order to is a reliable one possibility created, in case of failure of an adjustment or when "stalling" the engine starting ability or to allow a run-flat.

1

first Adjustment means (intake camshaft adjuster)

2

second Adjustment means (exhaust camshaft adjuster)

3, 3 ', 3' '

third Adjustment means (valve lift adjusting means)

4

Gas exchange valve (Inlet valve)

5

Gas exchange valve (Outlet)

6

intake camshaft

7

exhaust

8th

crankshaft

9

piston

10

cylinder

11

chain transmission

12

chain transmission

13

cam

14

cam

α _min

minimum value the valve overlap

α _max

maximum value the valve overlap

Claims (11)

Method for operating an internal combustion engine, wherein the internal combustion engine has first setting means ( 1 ) in the form of an intake camshaft adjuster, second adjusting means ( 2 ) in the form of an exhaust camshaft adjuster and third adjusting means ( 3 ) in the form of means for adjusting or influencing the stroke of the gas exchange valves ( 4 . 5 ), characterized in that when one of the adjustment means ( 1 . 2 . 3 ) the non-failed setting means ( 1 . 2 . 3 ) are adjusted so that the standard setting range of the adjustment means ( 1 . 2 . 3 ) is shifted to a modified runflat adjustment range to enable starting and / or runflat operation of the internal combustion engine. A method according to claim 1, characterized in that a) that in case of failure of the first or second adjusting means ( 1 . 2 ) the current position of the intake camshaft ( 6 ) and the exhaust camshaft ( 7 ) to the crankshaft ( 8th ) is determined, b) that then takes place a check whether a valve overlap between a predetermined minimum value (α _min ) and a given before maximum value (α _max ) by adjusting the non-failed setting means ( 1 . 2 ) is adjustable, c ') that in the event that this is possible, a valve overlap between the predetermined minimum value (α _min ) and the predetermined maximum value (α _max ) by adjusting the non-failed setting means ( 1 . 2 ) is set, c '') that in the event that this is not possible, a minimal possible valve overlap by adjusting the non-failed setting means ( 1 . 2 ) and d) that then the third setting means ( 3 ) are adjusted so that a maximum stroke of the gas exchange valves ( 4 . 5 ) and e) that finally the starting and / or the emergency operation of the internal combustion engine takes place with the settings made. Method according to claim 1, characterized in that a) that in case of failure of the third setting means ( 3 ) the current stroke of the gas exchange valves ( 4 . 5 ) is determined, b) that then a valve overlap between a predetermined minimum value (α _min ) and a predetermined maximum value (α _max ) by adjusting the non-failed first and second adjusting means ( 1 . 2 ) is set and c) that finally the starting and / or the emergency operation of the internal combustion engine takes place with the settings made. A method according to claim 2 or 3, characterized in that the predetermined minimum value (α _min ) of the valve overlap is 0 °. A method according to claim 2 or 3, characterized in that the predetermined maximum value (α _max ) of the valve overlap is 10 °. Method according to claim 1, characterized in that as intake camshaft adjuster ( 1 ) and as exhaust camshaft adjuster ( 2 ) electrically operated adjuster can be used. Method according to claim 1, characterized in that the means ( 3 ) for adjusting or influencing the stroke of the gas exchange valves ( 4 . 5 ) controlled or non-failure controlled can set a small or a large valve lift. Method according to claim 1, characterized in that that in addition at least one further engine parameter according to a predetermined algorithm adapted to the emergency operation. Method according to claim 8, characterized in that that in addition the idle speed according to a predetermined algorithm is adapted to the emergency operation. Method according to claim 8, characterized in that that in addition the injection timing according to a predetermined algorithm is adapted to the emergency operation. Method according to claim 8, characterized in that that in addition the ignition point according to one predetermined algorithm is adapted to the emergency operation.